JCLB-03874; No of Pages 6 Clinical Biomechanics xxx (2014) xxx–xxx
Contents lists available at ScienceDirect
Clinical Biomechanics journal homepage: www.elsevier.com/locate/clinbiomech
Bilateral symmetry in lower extremity mechanics during stair ascent and descent following a total hip arthroplasty: A one-year longitudinal study☆ Robin M. Queen a,b,⁎, David E. Attarian a, Michael P. Bolognesi a, Robert J. Butler b,c a b c
Department of Orthopaedic Surgery, Duke University Medical Center, Box 3956, Durham, NC 27710, USA Michael W. Krzyzewski Human Performance Research Laboratory, DUMC 3435, Duke University Medical Center, Durham, NC 27710, USA Division of Physical Therapy, Department of Orthopaedic Surgery, 2200 West Main St., Durham, NC 27705, USA
a r t i c l e
i n f o
Article history: Received 29 April 2014 Accepted 11 November 2014 Keywords: Total hip arthroplasty Limb symmetry Stair climbing Hip osteoarthritis Walking mechanics
a b s t r a c t Background: Total hip arthroplasty is the standard treatment to reduce pain and improve function in people with advanced hip osteoarthritis; however, persisting asymmetrical gait patterns have been identified in level walking. Therefore, this study evaluated limb asymmetries during stair ascent and descent in patients pre-operatively through 1 year after a hip replacement. It was hypothesized that lower extremity mechanics would improve on the surgical side, but asymmetries would persist through one year. Methods: Kinematics and kinetics were collected during seven ascending and descending trials pre-operatively, 6 weeks, and 1 year post-operatively for 42 hip replacement patients. Data were analyzed using 2 ∗ 3 (Limb ∗ Time) within-subject repeated measures analyses of variance (ANOVAs) to determine significant differences between limbs across time (P b .05). Findings: Significant changes across time, independent of limb included: peak hip flexion, extension, and adduction during ascent. Peak hip flexion and extension, hip flexion moment, adduction and abduction moments, and propulsive vertical ground reaction force were different during descent (P b .05). Independent of time, significant asymmetries between limbs were observed in peak hip flexion, hip abduction, and hip extension moments during ascent, and in peak hip abduction moment during descent (P b .05). Interpretation: Abnormal movement patterns on the surgical side increase demands on other joints and could lead to permanent joint damage. These side-to-side differences in joint mechanics should be addressed during the early post-operative period through additional interventions in an attempt to normalize the differences and potentially improve long-term joint health throughout the lower extremity. © 2014 Elsevier Ltd. All rights reserved.
1. Introduction Symptomatic hip osteoarthritis (OA) affects 9.2% of people over the age of 45 and this prevalence increases with age (Arden and Nevitt, 2006; Lawrence et al., 2008). End-stage hip OA is a debilitating condition that limits mobility and physical function, and for many patients, palliative care provides no pain relief or lifestyle improvement (Croft et al., 2002). Total hip arthroplasty (THA) has therefore become the standard of care to reduce pain and improve function in individuals with advanced hip OA (Kiebzak et al., 1997). In the United States, over 285,000 hip replacements are performed each year to address this painful and functionally limiting pathology (JRH, 2011).
☆ Source of funding: No funding was received for this study. ⁎ Corresponding author at: Michael W. Krzyzewski Human Performance Lab, Department of Orthopaedic Surgery, Duke University Medical Center, Box 3435, Durham, NC 27710, USA. E-mail address: [email protected] (R.M. Queen).
Most THA patients report improvement in outcomes with respect to pain relief, improved functional mobility during daily activities, overall health and quality of life following surgery (Berend et al., 2004; Espehaug et al., 1998; Jones et al., 2001; Kiebzak et al., 1997; Laupacis et al., 1993; Montin et al., 2008; Ogonda et al., 2005). Despite these positive post-operative self-reported measures, asymmetrical gait patterns between limbs during level walking have been reported up to 1-year after surgery. Prior gait analysis studies of THA patients have reported unequal spatiotemporal variables and asymmetric gait mechanics between limbs following surgery (Isobe et al., 1998; McCrory et al., 2001). Decreased peak hip flexion and peak extension as well as the associated range of motion (Miki et al., 2004) have also been found for the surgical limb during post-operative level walking (Queen et al., 2011b). Additionally, reduced muscle strength (Shih et al., 1994) and decreased energy expenditure have been observed for the operative limb in comparison with the non-operative limb (Loizeau et al., 1995) which confirms the presence of post-operative functional asymmetries following THA. In addition, post-operative ipsilateral muscle weakness
http://dx.doi.org/10.1016/j.clinbiomech.2014.11.004 0268-0033/© 2014 Elsevier Ltd. All rights reserved.
Please cite this article as: Queen, R.M., et al., Bilateral symmetry in lower extremity mechanics during stair ascent and descent following a total hip arthroplasty: A one-year longitudinal study, Clin. Biomech. (2014), http://dx.doi.org/10.1016/j.clinbiomech.2014.11.004
2
R.M. Queen et al. / Clinical Biomechanics xxx (2014) xxx–xxx
(Reardon et al., 2001) and atypical joint motion have been associated with asymmetrical limb loading (Talis et al., 2008). As a result of these issues, much research has focused on asymmetries during level walking after THA (Beaulieu et al., 2010; Isobe et al., 1998; McCrory et al., 2001; Queen et al., 2011b); however, few studies have examined the functional adaptations of the surgical limb adopted during more challenging tasks, such as stair climbing (Queen et al., 2013a; Shrader et al., 2009). Mechanically, stair ascent requires larger hip range of motion combined with greater muscle force at the hip in order to lift the subject's body mass, and therefore, may emphasize asymmetries otherwise undetected during level walking (Costigan et al., 2002; Talis et al., 2008). Compared to level walking, it has been reported that ascending stairs increases implant torque by 83% (Bergmann et al., 2001) and generates greater sagittal plane moments, placing greater strain on the hip extensor mechanism (Kirkwood et al., 1999; Nadeau et al., 2003). Previous studies in the area of knee osteoarthritis and total knee replacement (TKA) have examined stair climbing. These studies have reported that improvements in stair climbing ability were directly related to an increase in lower limb muscle strength and decreased pain (Hicks-Little et al., 2011; Unver et al., 2014; Whitchelo et al., 2014). The few kinematic studies that have examined stair climbing capabilities in hip replacement populations have found both angular and loading asymmetries (Shrader et al., 2009). THA patients 3 months following surgery exhibit reduced abduction and extension moments and irregular muscle firing of the hip while ascending stairs, which alter hip mechanics and hip joint loading following surgery (Shrader et al., 2009). Overall, a 20% difference in vertical ground reaction forces between the surgical and non-surgical limbs has been reported during tasks as physically demanding as stair climbing (Talis et al., 2008). Furthermore, previous studies have reported that THA patients ascend stairs with increased hip flexion angles and decreased hip extension angles, and descend stairs with decreased hip flexion moments 18 months post-op when compared to healthy controls (Queen et al., 2013a). Further assessment of limb symmetry during stair climbing is necessary to identify the subtle, but clinically important, biomechanical strategies adopted in post-operative THA patients that highlight areas of focus for early post-operative physical therapy in order to optimize surgical outcomes. While previous research on stair ascent and descent early after THA has focused on kinematic comparisons between approaches or treatment groups, these have been limited in statistical power. Little is known regarding the functional adaptations adopted by THA patients immediately following surgery compared to pre-operative mechanics. Therefore, the purpose of this study was to evaluate limb asymmetry during stair ascent and descent in patients across time from prior to surgery through 6 weeks and 1 year post-THA. It was hypothesized that stair climbing mechanics would improve on the surgical side during the first year of recovery following THA. In addition, it was hypothesized that significant side-to-side asymmetry would exist pre-operatively and that these asymmetries would persist up to 1 year following THA. 2. Methods 2.1. Subjects An a-priori power analysis was completed utilizing data that was collected in the laboratory environment to provide estimates of normative values for stair climbing as well as expected bilateral differences in THA patients (Queen et al., 2013a, 2014). To complete the analysis an α = 0.05, β = 0.20, and clinically relevant difference of 15% were utilized as standard coefficients for all of the variables of interest in the study. The results of the power analysis suggested that between 10 and 35 subjects were necessary to observe statistically significant findings. As a result of this analysis, a total of 42 subjects (22 men, 20 women) were recruited and fully completed the study. The mean age,
height, and weight were 55.8 (SD 8.9 years), 1.73 (SD 0.10 m), and 80.4 (SD 19.4 kg), respectively. To participate, all subjects had to be older than 35 years and had to be scheduled to have a primary THA within four weeks of pre-operative testing. Patients with lower extremity surgery in the past five years, serious neurological disorders, and current pain in any other lower extremity joint were excluded from consideration for the study. 75 total subjects were initially enrolled for the study, however 21 were excluded due to missing a time point at either 6 weeks or 1 year following surgery and 12 were excluded due to an inability to complete the stair climbing task in accordance with study design (only one foot on a step at a time) at one of the time points. All patients reviewed and signed the medical center's institutional review board-approved informed consent form prior to participation. 2.2. Data collection and stair negotiation analysis Data collection consisted of preliminary questionnaires, anthropometric data, and stair climbing analysis. Harris hip scores (HHS) were obtained, as well as the 12-item Short-Form Health Survey (SF-12), UCLA Score, and Duke Activity Scale for Arthroplasty Patients (ASAP). Anthropometric measures recorded include bilateral foot length and width, height, weight, age, and time from surgical intervention. Reflective markers were placed by a single tester, using the methodology that has been previously reported, on 39 prominent anatomical landmarks with one offset marker placed posteriorly on the right scapula (Queen et al., 2011a, 2011b). Patients were then instructed to stand with a neutral posture within view of the motion capture system in order to record a static standing trial. Markers were recorded using an 8 camera real-time motion capture system (Motion Analysis Inc., Santa Rosa, CA, USA) sampling at 120 Hz. Once static data was obtained, 10 of the markers were removed for the remainder of study (Queen et al., 2011a). Dynamic assessment consisted of 7 stair ascending and 7 descending trials using a step-over-step technique at the patients' desired, self-selected speed. Stair dimensions were measured to be 29 cm in width and 17.5 cm in tread height. Ground reaction forces were measured using 4 force plates (AMTI, Watertown, MA, USA) embedded in the floor at 1200 Hz. The set of four stairs were mounted on 2 of the plates in order to obtain ground reaction force data during both stair ascending and descending (Fig. 1). For stair climbing trials, subjects were asked to walk barefoot to avoid changes in ground reaction forces due to footwear. The 3D coordinate data were filtered using a low-pass Butterworth filter at 7 Hz and the ground reaction force data were filtered using a low-pass Butterworth filter at 100 Hz using Visual 3D software (C-Motion, Bethesda, Maryland, USA). The global optimization method available in Visual 3D was used to minimize any soft tissue artifact. Joint angles were calculated as Cardan angles between adjacent local segments with an order of rotation of flexion– extension, abduction–adduction, and internal rotation–external rotation. Joint moments were calculated through an inverse dynamic approach and transferred into the local segment coordinate system and were expressed as internal moments. The lower extremity variables of interest to determine significant differences between the surgical and non-surgical limbs or between the preoperative and post-operative time points included: bilateral peak hip flexion and extension, hip abduction and adduction kinematics and kinetics and peak vertical ground reaction forces (vGRFs). Variables were normalized from initial contact to toe off on both the surgical and non-surgical sides as a percentage of the stance phase, vGRF data was normalized to the body weight, while moments were normalized to height and weight for each subject. The timing of the analysis took place from initial contact of one foot on the second step to toe off of the contralateral foot on the third step. This procedure was repeated at 6 weeks and one year following surgery to examine the changes in mechanics across time. The choice of these two time points was based on the times that these patients returned for clinical assessments with the treating surgeon.
Please cite this article as: Queen, R.M., et al., Bilateral symmetry in lower extremity mechanics during stair ascent and descent following a total hip arthroplasty: A one-year longitudinal study, Clin. Biomech. (2014), http://dx.doi.org/10.1016/j.clinbiomech.2014.11.004
R.M. Queen et al. / Clinical Biomechanics xxx (2014) xxx–xxx
3
3.2. Stair ascent During the stair ascent, the most common findings were reported either between limbs or across time with no observable interactions. Peak hip flexion (P = .002), hip extension (P = .001) and hip adduction (P = .039) all demonstrated changes across time, independent of limb, during stair ascent. Peak hip flexion decreased while peak hip extension increased over time with the greatest difference existing between 6 weeks and one year post-operatively. During this same time period it was also observed that peak hip adduction increased (Table 1). In addition to the changes in kinematics it was also observed that there was an increase in the flexion (P = 0.001), adduction (P b 0.001), and abduction (P = 0.027) moments as well as the weight acceptance (P = 0.024) and propulsion (P = 0.039) vertical ground reaction forces. Peak hip flexion (P = .001), peak hip abduction (P = .009), and peak hip extension moments (P = .013) all demonstrated differences between the surgical and non-surgical limbs, with the surgical limb exhibiting lower values for all variables independent of time (Fig. 2). No differences existed for any of the other study variables of interest. 3.3. Stair descent
Fig. 1. Example of data collection set-up with the stairs attached to the force plates.
2.3. Data analysis Subjects underwent one of three surgical approaches: the DL or modified Hardinge (n = 13), the standard Posterior (n = 19), or the AL or modified Watson–Jones approach (n = 10). Surgeries were performed by one of three surgeons. Previous comparisons of hip mechanics during gait between surgical approaches have found no significant kinematic, kinetic, or spatiotemporal differences (Queen et al., 2011a, 2013b, 2014) and therefore, in our statistical analysis, these groups were not compared. Data were collected bilaterally to examine side-to-side differences in lower extremity mechanics during stair ascending and descending across different time points; pre-operatively, 6 weeks, and one year following THA. The surgical and non-surgical sides were examined across time using a 2 × 3 (Limb × Time) within subject repeated measures ANOVA with appropriate Tukey's post-hoc testing. In addition, the patient reported outcomes (Harris Hip score and SF-12) were compared across time using a 1 × 3 within subject repeated measures ANOVA. The level of significance set was set a-priori at P b .05.
3. Results 3.1. Patient reported outcomes The Harris Hip score as well as the Physical Composite Score (PCS) for the SF-12 were different (P b 0.001) between each time point (pre-op, 6 weeks, and 1 year). The Harris Hip Score improved from 57.35 (SD 9.92) pre-op to 75.18 (SD 11.14) at 6 weeks post-op and by 1 year post-op that Harris Hip score in these THA patients was 91.18 (SD 7.64). When examining the SF-12 PCS these THA patients demonstrated an improvement from 32.18 (SD 7.36) pre-op to 36.47 (SD 6.90) at 6 weeks post-op and then finally reported an SF-12 PSC of 54.80 (SD 5.54) by 1 year following surgery. No difference (P = 0.107) was found in the Mental Health Composite Score (MCS) between any of the time points (57.41 [SD 11.94] — pre-op, 59.59 [SD 4.55] — 6 weeks, and 54.18 [SD 7.59] 1 year post-op).
During stair descent, the majority of the variables differed solely between sides or over time with only one variable exhibiting an interaction between sides and across time. During stair descent, peak hip flexion (P b .001), hip extension (P b .001), hip flexion moment (P = .007), hip adduction moment (P = .004), hip abduction moment (P b .001), and propulsive vGRF (P b .001) were all different across time, independent of limb. Peak hip flexion, and the propulsive GRF decreased, while the peak hip extension, adduction, and abduction moments all increased by one year following THA when compared to the pre-operative time point (Table 2). Independent of time, a difference was observed in the peak hip abduction moment (P = .003) between the surgical and non-surgical limbs, with the surgical limb experiencing a smaller abduction moment than the surgical limb (Table 2). The peak vertical ground reaction force during weight acceptance was the only variable to display an interaction between limbs over the course of the study. The weight acceptance vertical GRF increased post-operatively for both the surgical and non-surgical limbs with the surgical limb demonstrating a greater increase in the weight acceptance GRF when compared to the non-surgical side (Fig. 3). 4. Discussion Total hip arthroplasty (THA) for the treatment of end-stage hip OA has been previously shown to significantly improve patient pain and clinical outcomes (Berend et al., 2004; Espehaug et al., 1998; Jones et al., 2001; Kiebzak et al., 1997; Laupacis et al., 1993; Montin et al., 2008; Ogonda et al., 2005). The results of the current study are in agreement with previous studies that have demonstrated improvements in patient reported outcomes following THA (Berend et al., 2004; Espehaug et al., 1998; Jones et al., 2001; Kiebzak et al., 1997; Laupacis et al., 1993; Montin et al., 2008; Ogonda et al., 2005). In addition, this study provides important longitudinal information regarding the post-operative function between limbs of THA patients during the physically-demanding tasks of ascending and descending stairs. We expected that lower extremity mechanics during stair negotiation would improve during the first year of recovery, and our results demonstrate that by one year post-operatively, THA patients do demonstrate improvements in the range of motion sagittal plane kinematics, that shift the pre-operative values towards those that have previously been associated with healthy subjects at one year following THA (Nadeau et al., 2003; Protopapadaki et al., 2007; Queen et al., 2013a). Specifically, these THA patients significantly decreased the amount of peak hip flexion and increased the amount of peak hip extension over time, independent of limb. Although not measured in this study, the
Please cite this article as: Queen, R.M., et al., Bilateral symmetry in lower extremity mechanics during stair ascent and descent following a total hip arthroplasty: A one-year longitudinal study, Clin. Biomech. (2014), http://dx.doi.org/10.1016/j.clinbiomech.2014.11.004
4
R.M. Queen et al. / Clinical Biomechanics xxx (2014) xxx–xxx
Table 1 Peak hip kinematics and kinetics across time independent of limb during stair ascent. (Values reported as the mean (SD).)
Flexion (deg)* Extension (deg)* Adduction (deg)* Abduction (deg) Flexion moment (BW ∗ BH)¥ Extension moment (BW ∗ BH) ADD moment (BW ∗ BH)* ABD moment (BW ∗ BH)* WA vertical GRF (BW)* Prop. vertical GRF (BW)*
Pre-op
6-weeks post-op
1-year post-op
P value
62.3 (12.1) 11.4 (13.4) 8.06 (5.63) −4.39 (4.55) 0.078 (0.104) −0.792 (0.283) 0.161 (0.118) −0.758 (0.183) 0.955 (0.123) 1.053 (0.146)
63.1 (8.9) 11.5 (9.3) 8.73 (4.33) −3.38 (3.92) 0.130 (0.138) −0.782 (0.192) 0.159 (0.069) −0.780 (0.150) 0.956 (0.077) 1.085 (0.107)
58.0 (6.3) 5.6 (6.8) 10.4 (4.28) −3.35 (3.83) 0.162 (0.143) −0.870 (0.307) 0.221 (0.089) −0.840 (0.185) 0.996 (0.067) 1.100 (0.098)
0.003 0.001 0.013 0.203 0.001 0.092 b0.001 0.027 0.024 0.039
* = Significant difference between pre-op and Post-1-year, Post-6-weeks and Post-1-year. ¥ = Significant difference between every time points. + = Significant difference between pre-op and Post-1-year. BW ∗ BH = Normalization of the joint moments to the product of body weight and body height. ADD = Adduction. ABD = Abduction. WA = Weight acceptance. Prop. = Propulsive.
Surgical
Non-Surgical
Flexion Angle (Deg)
75
*
70 65 60 55 50 Surgical
Non-Surgical
A) Hip Flexion Surgical
Non-Surgical
ABD Angle (Deg)
0 -1 -2 -3 -4 -5 -6 -7 -8 -9 -10
* B) Hip Abducon Surgical
Non-Surgical
Extension Moment (NM/kg)
1.2 1
*
0.8 0.6 0.4 0.2 0
C) Hip Extension Moment Fig. 2. Hip kinematics and kinetics between limbs independent of time during stair ascent. The * indicates a significant difference between the surgical and non-surgical limbs. A) Hip flexion, B) hip abduction and C) hip extension moments.
initial increase in hip flexion on the surgical limb that was observed pre-operatively may be due to increased forward trunk lean in order to propel the body forward while ascending the stairs which may have developed as a compensatory strategy due to the pain and disability associated with end stage hip osteoarthritis (Queen et al., 2013a). This compensatory action shifts the body's center of mass in a more forward position, thus accomplishing the task while reducing the joint compressive force on the affected hip. Decreased hip flexion seen one year after surgery may be indicative of improved strength and decreased pain resulting in a patients' willingness to use the surgical hip more while maintaining a more neutral trunk position. However, while the peak hip extension angle increased one year after surgery, the peak hip extension value indicated that these patients were still in a small degree of hip flexion during stair climbing, whereas healthy control subjects usually ascend the stairs with some hip extension at the end of the stance phase (Lamontagne et al., 2011; Nadeau et al., 2003; Protopapadaki et al., 2007; Shrader et al., 2009). This suggests that despite improvements in stair climbing mechanics, THA patients do not achieve the same level of hip extension as healthy individuals and as a result are still using compensatory strategies during stair climbing potentially as a result of persistent extensor mechanism weakness or mobility limitations (Queen et al., 2013a; Shrader et al., 2009). Side-to-side differences in lower extremity mechanics continue to persist up to 1 year following THA, as hypothesized. Although significant differences were observed across time for both the surgical and nonsurgical limbs, the non-surgical side was still being used more than the surgical side, indicated by the decreased peak hip flexion and abduction angles and peak hip extension moment on the non-surgical side. Previous literature has indicated that the internal extension moment correlates with the activation of the extensor mechanism during stair ascent in order to make this step transition (McFadyen and Winter, 1988). Therefore, the asymmetrical side-to-side peak extension moments reported in this study highlight the inability, even one year following surgery, of the extensor mechanism to achieve the normal extension moments bilaterally that are required during stair negotiation (Queen et al., 2013a). It is no surprise that deficits in the hip abduction angle on the surgical limb were also noted in comparison with the non-surgical limb, a finding that has previously been reported in this patient population during level walking (Shrader et al., 2009). Previous literature has indicated the importance of the hip abductors in controlling lateral pelvic obliquity and for raising the pelvis on the contralateral side in order to acquire sufficient lateral elevation so that the swing leg can successfully avoid the intermediate step (Nadeau et al., 2003). In addition, previous work
Please cite this article as: Queen, R.M., et al., Bilateral symmetry in lower extremity mechanics during stair ascent and descent following a total hip arthroplasty: A one-year longitudinal study, Clin. Biomech. (2014), http://dx.doi.org/10.1016/j.clinbiomech.2014.11.004
R.M. Queen et al. / Clinical Biomechanics xxx (2014) xxx–xxx
5
Table 2 Peak hip kinematics and kinetics across time independent of limb during stair descent. (Values reported as mean (standard error of the mean).)
Flexion (deg)* Extension (deg)* Adduction (deg) Abduction (deg) Flexion moment (BW ∗ BH)* Extension moment (BW ∗ BH) ADD moment (BW ∗ BH)* ABD moment (BW ∗ BH)¥ WA vertical GRF (BW)* Prop. vertical GRF (BW)*
Pre-op
6-weeks post-op
1-year post-op
P value
34.3 (8.9) 19.1 (8.5) 5.4 (4.8) −2.3 (4.3) 0.390 (0.234) −0.266 (0.319) 0.099 (0.055) −0.880 (0.277) 1.19 (0.21) 0.93 (0.05)
32.1 (9.0) 16.9 (8.3) 6.1 (4.0) −2.6 (3.2) 0.418 (0.324) −0.286 (0.252) 0.105 (0.072) −0.982 (0.256) 1.26 (0.27) 0.94 (0.08)
25.6 (8.0) 11.2 (7.2) 6.5 (4.2) −2.7 (3.6) 0.594 (0.557) −0.323 (0.300) 0.138 (0.077) −1.025 (0.222) 1.35 (0.16) 0.89 (0.08)
b0.001 b0.001 0.076 0.842 0.007 0.298 0.004 b0.001 b0.001 b0.001
* = Significant difference between pre-op and Post-1-year, Post-6-weeks and Post-1-year. ¥ = Significant difference between pre-op and Post-6-weeks, pre-op and Post-1-year. BW ∗ BH = Normalization of the joint moments to the product of body weight and body height. ADD = Adduction. ABD = Abduction. WA = Weight acceptance. Prop. = Propulsion.
in this patient population indicated that these patients demonstrated distal compensations, notably on the contralateral limb, to account for the limited hip motion in order to climb the stairs (Lamontagne et al., 2011). Further research is warranted to understand the residual effects that compensatory mechanics at the affected joint could have on adjacent joints and the potential for joint damage at these joints. This may result from increased loading and motion in order to compensate for limitations in motion at the surgical joint. The differences observed during stair descending were very similar to those reported for stair ascending with the THA patients demonstrating a more symmetrical movement pattern with an improved range of motion by one year post-operatively (Protopapadaki et al., 2007). The ability of our THA patients to achieve a peak hip flexion moment similar to healthy controls is indicative of improved muscle activation of the extensor mechanism. On the contrary, while the peak hip flexion and extension angles found in our patients were similar to those found in previous hip replacement populations during stair descent (Queen et al., 2013a), these values still did not reach those associated with healthy controls, indicating that these patients were still using compensatory strategies during stair descent. A significant side-to-side asymmetry continued to persist in the peak hip abduction moment, even one year following surgery. When the foot strikes the stair below, the abductors must generate a moment with enough magnitude to sustain the body weight as it is transferred medially to the stance limb (Kirkwood et al., 1999). This prevents the drop of the contralateral pelvis, thus potentially
playing a pivotal role in maintaining balance and stability (Jacquelin Perry, 1992). Therefore, abductor weakness, present following a THA, could play a crucial role in the functional limitations experienced by this patient population while performing more difficult daily tasks that require more strength and stability during single leg stance. One of the limitations of this study is the small sample size. Although there was sufficient power to detect side-to-side differences it is possible that additional biomechanical differences could be observed with an increase in the sample size. In addition, no healthy control data was collected as part of this study. As a result, our subject data was compared to normative values reported previously in the literature. The lack of standardized methods, such as stair dimensions, results in difficult comparisons of stair climbing data across studies. In addition, the use of skin based motion capture techniques introduces some soft tissue artifact which cannot be avoided and is a known limitation of this type of data collection. Finally, the operations performed as part of this study were not completed by a single surgeon and more than one surgical implant was used. Differences in surgical experience and implant could have altered patient function following surgery, however, limited information exists in the literature to support the idea that implant and surgeon would alter lower extremity mechanics following THA. Conclusions The asymmetries reported in this study that could have resulted from abductor and extensor weakness are more noticeable during stair ascending and descending due to the increased demands placed on these muscle groups during stair climbing when compared
Surgical
Non-Surgical
1.8 1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 0 Pre
6 weeks
1 year
Fig. 3. Changes across time and between limbs for weight acceptance GRF during stair ascent.
Please cite this article as: Queen, R.M., et al., Bilateral symmetry in lower extremity mechanics during stair ascent and descent following a total hip arthroplasty: A one-year longitudinal study, Clin. Biomech. (2014), http://dx.doi.org/10.1016/j.clinbiomech.2014.11.004
6
R.M. Queen et al. / Clinical Biomechanics xxx (2014) xxx–xxx
with level walking. These abnormal movement patterns on the surgical limb could be the result of either the patients' inability or reluctance to utilize the affected hip; nevertheless, the increased demand on other joints may lead to long term joint wear and pain. Based on the results of this study, future work should examine whether the addition of a focused physical therapy intervention could decrease the side-to-side asymmetries and restore more normal function in this patient population. The addition of more dynamic and demanding tasks needs to be considered when assessing post-operative physical function as the patients receiving THA continue to place more demand on these implants through increasing activity. The side-to-side differences in joint mechanics reported in this study should potentially be addressed during the early post-operative period through additional interventions in an attempt to normalize the differences and potentially improve long-term joint health throughout the lower extremity. References Arden, N., Nevitt, M.C., 2006. Osteoarthritis: epidemiology. Best Pract. Res. Clin. Rheumatol. 20, 3–25. Beaulieu, M.L., Lamontagne, M., Beaule, P.E., 2010. Lower limb biomechanics during gait do not return to normal following total hip arthroplasty. Gait Posture 32, 269–273. Berend, K.R., Lombardi, A.V., Mallory, T.H., Dodds, K.L., Adams, J.B., 2004. Cementless double-tapered total hip arthroplasty in patients 75 years of age and older. J. Arthroplast. 19, 288–295. Bergmann, G., Deuretzbacher, G., Heller, M., Graichen, F., Rohlmann, A., Strauss, J., Duda, G.N., 2001. Hip contact forces and gait patterns from routine activities. J. Biomech. 34, 859–871. Costigan, P.A., Deluzio, K.J., Wyss, U.P., 2002. Knee and hip kinetics during normal stair climbing. 16, 31–37. Croft, P., Lewis, M., Wynn Jones, C., Coggon, D., Cooper, C., 2002. Health status in patients awaiting hip replacement for osteoarthritis. Rheumatology 41, 1001–1007. Espehaug, B., Havelin, L.I., Engesaeter, L.B., Langeland, N., Vollset, S.E., 1998. Patient satisfaction and function after primary and revision total hip replacement. Clin. Orthop. Relat. Res. 135–148. Hicks-Little, C.A., Peindl, R.D., Hubbard, T.J., Scannell, B.P., Springer, B.D., Odum, S.M., Fehring, T.K., Cordova, M.L., 2011. Lower extremity joint kinematics during stair climbing in knee osteoarthritis. Med. Sci. Sports Exerc. 43, 516–524. Isobe, Y., Okuno, M., Otsuki, T., Yamamoto, K., 1998. Clinical study on arthroplasties for osteoarthritic hip by quantitative gait analysis. Comparison between total hip arthroplasty and bipolar endoprosthetic arthroplasty. Biomed. Mater. Eng. 8, 167–175. Jacquelin Perry, B.S., 1992. Gait Analysis: Normal and Pathological Function. Slack Incorporated. Jones, C.A., Voaklander, D.C., Johnston, D.W., Suarez-Almazor, M.E., 2001. The effect of age on pain, function, and quality of life after total hip and knee arthroplasty. Arch. Intern. Med. 161, 454–460. JRH, F., 2011. Total Hip Replacement. American Academy of Orthopaedic Surgeons. Kiebzak, G.M., Vain, P.A., Gregory, A.M., Mokris, J.G., Mauerhan, D.R., 1997. SF-36 general health status survey to determine patient satisfaction at short-term follow-up after total hip and knee arthroplasty. J. South. Orthop. Assoc. 6, 169–172. Kirkwood, R.N., Culham, E.G., Costigan, P., 1999. Hip moments during level walking, stair climbing, and exercise in individuals aged 55 years or older. Phys. Ther. 79, 360–370. Lamontagne, M., Beaulieu, M.L., Beaule, P.E., 2011. Comparison of joint mechanics of both lower limbs of THA patients with healthy participants during stair ascent and descent. J. Orthop. Res. 29, 305–311. Laupacis, A., Bourne, R., Rorabeck, C., Feeny, D., Wong, C., Tugwell, P., Leslie, K., Bullas, R., 1993. The effect of elective total hip replacement on health-related quality of life. J. Bone Joint Surg. Am. 75, 1619–1626.
Lawrence, R.C., Felson, D.T., Helmick, C.G., Arnold, L.M., Choi, H., Deyo, R.A., Gabriel, S., Hirsch, R., Hochberg, M.C., Hunder, G.G., Jordan, J.M., Katz, J.N., Kremers, H.M., Wolfe, F., National Arthritis Data, W., 2008. Estimates of the prevalence of arthritis and other rheumatic conditions in the United States. Part II. Arthritis Rheum. 58, 26–35. Loizeau, J., Allard, P., Duhaime, M., Landjerit, B., 1995. Bilateral gait patterns in subjects fitted with a total hip prosthesis. Arch. Phys. Med. Rehabil. 76, 552–557. McCrory, J.L., White, S.C., Lifeso, R.M., 2001. Vertical ground reaction forces: objective measures of gait following hip arthroplasty. Gait Posture 14, 104–109. McFadyen, B.J., Winter, D.A., 1988. An integrated biomechanical analysis of normal stair ascent and descent. J. Biomech. 21, 733–744. Miki, H., Sugano, N., Hagio, K., Nishii, T., Kawakami, H., Kakimoto, A., Nakamura, N., Yoshikawa, H., 2004. Recovery of walking speed and symmetrical movement of the pelvis and lower extremity joints after unilateral THA. J. Biomech. 37, 443–455. Montin, L., Leino-Kilpi, H., Suominen, T., Lepisto, J., 2008. A systematic review of empirical studies between 1966 and 2005 of patient outcomes of total hip arthroplasty and related factors. J. Clin. Nurs. 17, 40–45. Nadeau, S., McFadyen, B.J., Malouin, F., 2003. Frontal and sagittal plane analyses of the stair climbing task in healthy adults aged over 40 years: what are the challenges compared to level walking? Clin. Biomech. 18, 950–959. Ogonda, L., Wilson, R., Archbold, P., Lawlor, M., Humphreys, P., O'Brien, S., Beverland, D., 2005. A minimal-incision technique in total hip arthroplasty does not improve early postoperative outcomes. A prospective, randomized, controlled trial. J. Bone Joint Surg. Am. 87, 701–710. Protopapadaki, A., Drechsler, W.I., Cramp, M.C., Coutts, F.J., Scott, O.M., 2007. Hip, knee, ankle kinematics and kinetics during stair ascent and descent in healthy young individuals. Clin. Biomech. 22, 203–210. Queen, R.M., Butler, R.J., Watters, T.S., Kelley, S.S., Attarian, D.E., Bolognesi, M.P., 2011a. The effect of total hip arthroplasty surgical approach on postoperative gait mechanics. J. Arthroplasty 26, 66–71. Queen, R.M., Watters, T.S., Abbey, A.N., Sabesan, V.J., Vail, T.P., Bolognesi, M.P., 2011b. Gait symmetry: a comparison of hip resurfacing and jumbo head total hip arthroplasty patients. J. Arthroplasty 26, 680–685. Queen, R.M., Newman, E.T., Abbey, A.N., Vail, T.P., Bolognesi, M.P., 2013a. Stair ascending and descending in hip resurfacing and large head total hip arthroplasty patients. J. Arthroplast. 28, 684–689. Queen, R.M., Schaeffer, J.F., Butler, R.J., Berasi, C.C., Kelley, S.S., Attarian, D.E., Bolognesi, M.P., 2013b. Does surgical approach during total hip arthroplasty alter gait recovery during the first year following surgery? J. Arthroplast. 28, 1639–1643. Queen, R.M., Appleton, J.S., Butler, R.J., Newman, E.T., Kelley, S.S., Attarian, D.E., Bolognesi, M.P., 2014. Total hip arthroplasty surgical approach does not alter postoperative gait mechanics one year after surgery. PM R 6, 221–226 (quiz 226). Reardon, K., Galea, M., Dennett, X., Choong, P., Byrne, E., 2001. Quadriceps muscle wasting persists 5 months after total hip arthroplasty for osteoarthritis of the hip: a pilot study. Intern. Med. J. 31, 7–14. Shih, C.H., Du, Y.K., Lin, Y.H., Wu, C.C., 1994. Muscular recovery around the hip joint after total hip arthroplasty. Clin. Orthop. Relat. Res. 115–120. Shrader, M.W., Bhowmik-Stoker, M., Jacofsky, M.C., Jacofsky, D.J., 2009. Gait and stair function in total and resurfacing hip arthroplasty: a pilot study. Clin. Orthop. Relat. Res. 467, 1476–1484. Talis, V.L., Grishin, A.A., Solopova, I.A., Oskanyan, T.L., Belenky, V.E., Ivanenko, Y.P., 2008. Asymmetric leg loading during sit-to-stand, walking and quiet standing in patients after unilateral total hip replacement surgery. Clin. Biomech. 23, 424–433. Unver, B., Ertekin, O., Karatosun, V., 2014. Pain, fear of falling and stair climbing ability in patients with knee osteoarthritis before and after knee replacement: 6 month follow-up study. J. Musculoskelet. Rehabil. 27, 77–84. Whitchelo, T., McClelland, J.A., Webster, K.E., 2014. Factors associated with stair climbing ability in patients with knee osteoarthritis and knee arthroplasty: a systematic review. Disabil. Rehabil. 36 (13), 1051–1060.
Please cite this article as: Queen, R.M., et al., Bilateral symmetry in lower extremity mechanics during stair ascent and descent following a total hip arthroplasty: A one-year longitudinal study, Clin. Biomech. (2014), http://dx.doi.org/10.1016/j.clinbiomech.2014.11.004
Contents lists available at ScienceDirect
Clinical Biomechanics journal homepage: www.elsevier.com/locate/clinbiomech
Bilateral symmetry in lower extremity mechanics during stair ascent and descent following a total hip arthroplasty: A one-year longitudinal study☆ Robin M. Queen a,b,⁎, David E. Attarian a, Michael P. Bolognesi a, Robert J. Butler b,c a b c
Department of Orthopaedic Surgery, Duke University Medical Center, Box 3956, Durham, NC 27710, USA Michael W. Krzyzewski Human Performance Research Laboratory, DUMC 3435, Duke University Medical Center, Durham, NC 27710, USA Division of Physical Therapy, Department of Orthopaedic Surgery, 2200 West Main St., Durham, NC 27705, USA
a r t i c l e
i n f o
Article history: Received 29 April 2014 Accepted 11 November 2014 Keywords: Total hip arthroplasty Limb symmetry Stair climbing Hip osteoarthritis Walking mechanics
a b s t r a c t Background: Total hip arthroplasty is the standard treatment to reduce pain and improve function in people with advanced hip osteoarthritis; however, persisting asymmetrical gait patterns have been identified in level walking. Therefore, this study evaluated limb asymmetries during stair ascent and descent in patients pre-operatively through 1 year after a hip replacement. It was hypothesized that lower extremity mechanics would improve on the surgical side, but asymmetries would persist through one year. Methods: Kinematics and kinetics were collected during seven ascending and descending trials pre-operatively, 6 weeks, and 1 year post-operatively for 42 hip replacement patients. Data were analyzed using 2 ∗ 3 (Limb ∗ Time) within-subject repeated measures analyses of variance (ANOVAs) to determine significant differences between limbs across time (P b .05). Findings: Significant changes across time, independent of limb included: peak hip flexion, extension, and adduction during ascent. Peak hip flexion and extension, hip flexion moment, adduction and abduction moments, and propulsive vertical ground reaction force were different during descent (P b .05). Independent of time, significant asymmetries between limbs were observed in peak hip flexion, hip abduction, and hip extension moments during ascent, and in peak hip abduction moment during descent (P b .05). Interpretation: Abnormal movement patterns on the surgical side increase demands on other joints and could lead to permanent joint damage. These side-to-side differences in joint mechanics should be addressed during the early post-operative period through additional interventions in an attempt to normalize the differences and potentially improve long-term joint health throughout the lower extremity. © 2014 Elsevier Ltd. All rights reserved.
1. Introduction Symptomatic hip osteoarthritis (OA) affects 9.2% of people over the age of 45 and this prevalence increases with age (Arden and Nevitt, 2006; Lawrence et al., 2008). End-stage hip OA is a debilitating condition that limits mobility and physical function, and for many patients, palliative care provides no pain relief or lifestyle improvement (Croft et al., 2002). Total hip arthroplasty (THA) has therefore become the standard of care to reduce pain and improve function in individuals with advanced hip OA (Kiebzak et al., 1997). In the United States, over 285,000 hip replacements are performed each year to address this painful and functionally limiting pathology (JRH, 2011).
☆ Source of funding: No funding was received for this study. ⁎ Corresponding author at: Michael W. Krzyzewski Human Performance Lab, Department of Orthopaedic Surgery, Duke University Medical Center, Box 3435, Durham, NC 27710, USA. E-mail address: [email protected] (R.M. Queen).
Most THA patients report improvement in outcomes with respect to pain relief, improved functional mobility during daily activities, overall health and quality of life following surgery (Berend et al., 2004; Espehaug et al., 1998; Jones et al., 2001; Kiebzak et al., 1997; Laupacis et al., 1993; Montin et al., 2008; Ogonda et al., 2005). Despite these positive post-operative self-reported measures, asymmetrical gait patterns between limbs during level walking have been reported up to 1-year after surgery. Prior gait analysis studies of THA patients have reported unequal spatiotemporal variables and asymmetric gait mechanics between limbs following surgery (Isobe et al., 1998; McCrory et al., 2001). Decreased peak hip flexion and peak extension as well as the associated range of motion (Miki et al., 2004) have also been found for the surgical limb during post-operative level walking (Queen et al., 2011b). Additionally, reduced muscle strength (Shih et al., 1994) and decreased energy expenditure have been observed for the operative limb in comparison with the non-operative limb (Loizeau et al., 1995) which confirms the presence of post-operative functional asymmetries following THA. In addition, post-operative ipsilateral muscle weakness
http://dx.doi.org/10.1016/j.clinbiomech.2014.11.004 0268-0033/© 2014 Elsevier Ltd. All rights reserved.
Please cite this article as: Queen, R.M., et al., Bilateral symmetry in lower extremity mechanics during stair ascent and descent following a total hip arthroplasty: A one-year longitudinal study, Clin. Biomech. (2014), http://dx.doi.org/10.1016/j.clinbiomech.2014.11.004
2
R.M. Queen et al. / Clinical Biomechanics xxx (2014) xxx–xxx
(Reardon et al., 2001) and atypical joint motion have been associated with asymmetrical limb loading (Talis et al., 2008). As a result of these issues, much research has focused on asymmetries during level walking after THA (Beaulieu et al., 2010; Isobe et al., 1998; McCrory et al., 2001; Queen et al., 2011b); however, few studies have examined the functional adaptations of the surgical limb adopted during more challenging tasks, such as stair climbing (Queen et al., 2013a; Shrader et al., 2009). Mechanically, stair ascent requires larger hip range of motion combined with greater muscle force at the hip in order to lift the subject's body mass, and therefore, may emphasize asymmetries otherwise undetected during level walking (Costigan et al., 2002; Talis et al., 2008). Compared to level walking, it has been reported that ascending stairs increases implant torque by 83% (Bergmann et al., 2001) and generates greater sagittal plane moments, placing greater strain on the hip extensor mechanism (Kirkwood et al., 1999; Nadeau et al., 2003). Previous studies in the area of knee osteoarthritis and total knee replacement (TKA) have examined stair climbing. These studies have reported that improvements in stair climbing ability were directly related to an increase in lower limb muscle strength and decreased pain (Hicks-Little et al., 2011; Unver et al., 2014; Whitchelo et al., 2014). The few kinematic studies that have examined stair climbing capabilities in hip replacement populations have found both angular and loading asymmetries (Shrader et al., 2009). THA patients 3 months following surgery exhibit reduced abduction and extension moments and irregular muscle firing of the hip while ascending stairs, which alter hip mechanics and hip joint loading following surgery (Shrader et al., 2009). Overall, a 20% difference in vertical ground reaction forces between the surgical and non-surgical limbs has been reported during tasks as physically demanding as stair climbing (Talis et al., 2008). Furthermore, previous studies have reported that THA patients ascend stairs with increased hip flexion angles and decreased hip extension angles, and descend stairs with decreased hip flexion moments 18 months post-op when compared to healthy controls (Queen et al., 2013a). Further assessment of limb symmetry during stair climbing is necessary to identify the subtle, but clinically important, biomechanical strategies adopted in post-operative THA patients that highlight areas of focus for early post-operative physical therapy in order to optimize surgical outcomes. While previous research on stair ascent and descent early after THA has focused on kinematic comparisons between approaches or treatment groups, these have been limited in statistical power. Little is known regarding the functional adaptations adopted by THA patients immediately following surgery compared to pre-operative mechanics. Therefore, the purpose of this study was to evaluate limb asymmetry during stair ascent and descent in patients across time from prior to surgery through 6 weeks and 1 year post-THA. It was hypothesized that stair climbing mechanics would improve on the surgical side during the first year of recovery following THA. In addition, it was hypothesized that significant side-to-side asymmetry would exist pre-operatively and that these asymmetries would persist up to 1 year following THA. 2. Methods 2.1. Subjects An a-priori power analysis was completed utilizing data that was collected in the laboratory environment to provide estimates of normative values for stair climbing as well as expected bilateral differences in THA patients (Queen et al., 2013a, 2014). To complete the analysis an α = 0.05, β = 0.20, and clinically relevant difference of 15% were utilized as standard coefficients for all of the variables of interest in the study. The results of the power analysis suggested that between 10 and 35 subjects were necessary to observe statistically significant findings. As a result of this analysis, a total of 42 subjects (22 men, 20 women) were recruited and fully completed the study. The mean age,
height, and weight were 55.8 (SD 8.9 years), 1.73 (SD 0.10 m), and 80.4 (SD 19.4 kg), respectively. To participate, all subjects had to be older than 35 years and had to be scheduled to have a primary THA within four weeks of pre-operative testing. Patients with lower extremity surgery in the past five years, serious neurological disorders, and current pain in any other lower extremity joint were excluded from consideration for the study. 75 total subjects were initially enrolled for the study, however 21 were excluded due to missing a time point at either 6 weeks or 1 year following surgery and 12 were excluded due to an inability to complete the stair climbing task in accordance with study design (only one foot on a step at a time) at one of the time points. All patients reviewed and signed the medical center's institutional review board-approved informed consent form prior to participation. 2.2. Data collection and stair negotiation analysis Data collection consisted of preliminary questionnaires, anthropometric data, and stair climbing analysis. Harris hip scores (HHS) were obtained, as well as the 12-item Short-Form Health Survey (SF-12), UCLA Score, and Duke Activity Scale for Arthroplasty Patients (ASAP). Anthropometric measures recorded include bilateral foot length and width, height, weight, age, and time from surgical intervention. Reflective markers were placed by a single tester, using the methodology that has been previously reported, on 39 prominent anatomical landmarks with one offset marker placed posteriorly on the right scapula (Queen et al., 2011a, 2011b). Patients were then instructed to stand with a neutral posture within view of the motion capture system in order to record a static standing trial. Markers were recorded using an 8 camera real-time motion capture system (Motion Analysis Inc., Santa Rosa, CA, USA) sampling at 120 Hz. Once static data was obtained, 10 of the markers were removed for the remainder of study (Queen et al., 2011a). Dynamic assessment consisted of 7 stair ascending and 7 descending trials using a step-over-step technique at the patients' desired, self-selected speed. Stair dimensions were measured to be 29 cm in width and 17.5 cm in tread height. Ground reaction forces were measured using 4 force plates (AMTI, Watertown, MA, USA) embedded in the floor at 1200 Hz. The set of four stairs were mounted on 2 of the plates in order to obtain ground reaction force data during both stair ascending and descending (Fig. 1). For stair climbing trials, subjects were asked to walk barefoot to avoid changes in ground reaction forces due to footwear. The 3D coordinate data were filtered using a low-pass Butterworth filter at 7 Hz and the ground reaction force data were filtered using a low-pass Butterworth filter at 100 Hz using Visual 3D software (C-Motion, Bethesda, Maryland, USA). The global optimization method available in Visual 3D was used to minimize any soft tissue artifact. Joint angles were calculated as Cardan angles between adjacent local segments with an order of rotation of flexion– extension, abduction–adduction, and internal rotation–external rotation. Joint moments were calculated through an inverse dynamic approach and transferred into the local segment coordinate system and were expressed as internal moments. The lower extremity variables of interest to determine significant differences between the surgical and non-surgical limbs or between the preoperative and post-operative time points included: bilateral peak hip flexion and extension, hip abduction and adduction kinematics and kinetics and peak vertical ground reaction forces (vGRFs). Variables were normalized from initial contact to toe off on both the surgical and non-surgical sides as a percentage of the stance phase, vGRF data was normalized to the body weight, while moments were normalized to height and weight for each subject. The timing of the analysis took place from initial contact of one foot on the second step to toe off of the contralateral foot on the third step. This procedure was repeated at 6 weeks and one year following surgery to examine the changes in mechanics across time. The choice of these two time points was based on the times that these patients returned for clinical assessments with the treating surgeon.
Please cite this article as: Queen, R.M., et al., Bilateral symmetry in lower extremity mechanics during stair ascent and descent following a total hip arthroplasty: A one-year longitudinal study, Clin. Biomech. (2014), http://dx.doi.org/10.1016/j.clinbiomech.2014.11.004
R.M. Queen et al. / Clinical Biomechanics xxx (2014) xxx–xxx
3
3.2. Stair ascent During the stair ascent, the most common findings were reported either between limbs or across time with no observable interactions. Peak hip flexion (P = .002), hip extension (P = .001) and hip adduction (P = .039) all demonstrated changes across time, independent of limb, during stair ascent. Peak hip flexion decreased while peak hip extension increased over time with the greatest difference existing between 6 weeks and one year post-operatively. During this same time period it was also observed that peak hip adduction increased (Table 1). In addition to the changes in kinematics it was also observed that there was an increase in the flexion (P = 0.001), adduction (P b 0.001), and abduction (P = 0.027) moments as well as the weight acceptance (P = 0.024) and propulsion (P = 0.039) vertical ground reaction forces. Peak hip flexion (P = .001), peak hip abduction (P = .009), and peak hip extension moments (P = .013) all demonstrated differences between the surgical and non-surgical limbs, with the surgical limb exhibiting lower values for all variables independent of time (Fig. 2). No differences existed for any of the other study variables of interest. 3.3. Stair descent
Fig. 1. Example of data collection set-up with the stairs attached to the force plates.
2.3. Data analysis Subjects underwent one of three surgical approaches: the DL or modified Hardinge (n = 13), the standard Posterior (n = 19), or the AL or modified Watson–Jones approach (n = 10). Surgeries were performed by one of three surgeons. Previous comparisons of hip mechanics during gait between surgical approaches have found no significant kinematic, kinetic, or spatiotemporal differences (Queen et al., 2011a, 2013b, 2014) and therefore, in our statistical analysis, these groups were not compared. Data were collected bilaterally to examine side-to-side differences in lower extremity mechanics during stair ascending and descending across different time points; pre-operatively, 6 weeks, and one year following THA. The surgical and non-surgical sides were examined across time using a 2 × 3 (Limb × Time) within subject repeated measures ANOVA with appropriate Tukey's post-hoc testing. In addition, the patient reported outcomes (Harris Hip score and SF-12) were compared across time using a 1 × 3 within subject repeated measures ANOVA. The level of significance set was set a-priori at P b .05.
3. Results 3.1. Patient reported outcomes The Harris Hip score as well as the Physical Composite Score (PCS) for the SF-12 were different (P b 0.001) between each time point (pre-op, 6 weeks, and 1 year). The Harris Hip Score improved from 57.35 (SD 9.92) pre-op to 75.18 (SD 11.14) at 6 weeks post-op and by 1 year post-op that Harris Hip score in these THA patients was 91.18 (SD 7.64). When examining the SF-12 PCS these THA patients demonstrated an improvement from 32.18 (SD 7.36) pre-op to 36.47 (SD 6.90) at 6 weeks post-op and then finally reported an SF-12 PSC of 54.80 (SD 5.54) by 1 year following surgery. No difference (P = 0.107) was found in the Mental Health Composite Score (MCS) between any of the time points (57.41 [SD 11.94] — pre-op, 59.59 [SD 4.55] — 6 weeks, and 54.18 [SD 7.59] 1 year post-op).
During stair descent, the majority of the variables differed solely between sides or over time with only one variable exhibiting an interaction between sides and across time. During stair descent, peak hip flexion (P b .001), hip extension (P b .001), hip flexion moment (P = .007), hip adduction moment (P = .004), hip abduction moment (P b .001), and propulsive vGRF (P b .001) were all different across time, independent of limb. Peak hip flexion, and the propulsive GRF decreased, while the peak hip extension, adduction, and abduction moments all increased by one year following THA when compared to the pre-operative time point (Table 2). Independent of time, a difference was observed in the peak hip abduction moment (P = .003) between the surgical and non-surgical limbs, with the surgical limb experiencing a smaller abduction moment than the surgical limb (Table 2). The peak vertical ground reaction force during weight acceptance was the only variable to display an interaction between limbs over the course of the study. The weight acceptance vertical GRF increased post-operatively for both the surgical and non-surgical limbs with the surgical limb demonstrating a greater increase in the weight acceptance GRF when compared to the non-surgical side (Fig. 3). 4. Discussion Total hip arthroplasty (THA) for the treatment of end-stage hip OA has been previously shown to significantly improve patient pain and clinical outcomes (Berend et al., 2004; Espehaug et al., 1998; Jones et al., 2001; Kiebzak et al., 1997; Laupacis et al., 1993; Montin et al., 2008; Ogonda et al., 2005). The results of the current study are in agreement with previous studies that have demonstrated improvements in patient reported outcomes following THA (Berend et al., 2004; Espehaug et al., 1998; Jones et al., 2001; Kiebzak et al., 1997; Laupacis et al., 1993; Montin et al., 2008; Ogonda et al., 2005). In addition, this study provides important longitudinal information regarding the post-operative function between limbs of THA patients during the physically-demanding tasks of ascending and descending stairs. We expected that lower extremity mechanics during stair negotiation would improve during the first year of recovery, and our results demonstrate that by one year post-operatively, THA patients do demonstrate improvements in the range of motion sagittal plane kinematics, that shift the pre-operative values towards those that have previously been associated with healthy subjects at one year following THA (Nadeau et al., 2003; Protopapadaki et al., 2007; Queen et al., 2013a). Specifically, these THA patients significantly decreased the amount of peak hip flexion and increased the amount of peak hip extension over time, independent of limb. Although not measured in this study, the
Please cite this article as: Queen, R.M., et al., Bilateral symmetry in lower extremity mechanics during stair ascent and descent following a total hip arthroplasty: A one-year longitudinal study, Clin. Biomech. (2014), http://dx.doi.org/10.1016/j.clinbiomech.2014.11.004
4
R.M. Queen et al. / Clinical Biomechanics xxx (2014) xxx–xxx
Table 1 Peak hip kinematics and kinetics across time independent of limb during stair ascent. (Values reported as the mean (SD).)
Flexion (deg)* Extension (deg)* Adduction (deg)* Abduction (deg) Flexion moment (BW ∗ BH)¥ Extension moment (BW ∗ BH) ADD moment (BW ∗ BH)* ABD moment (BW ∗ BH)* WA vertical GRF (BW)* Prop. vertical GRF (BW)*
Pre-op
6-weeks post-op
1-year post-op
P value
62.3 (12.1) 11.4 (13.4) 8.06 (5.63) −4.39 (4.55) 0.078 (0.104) −0.792 (0.283) 0.161 (0.118) −0.758 (0.183) 0.955 (0.123) 1.053 (0.146)
63.1 (8.9) 11.5 (9.3) 8.73 (4.33) −3.38 (3.92) 0.130 (0.138) −0.782 (0.192) 0.159 (0.069) −0.780 (0.150) 0.956 (0.077) 1.085 (0.107)
58.0 (6.3) 5.6 (6.8) 10.4 (4.28) −3.35 (3.83) 0.162 (0.143) −0.870 (0.307) 0.221 (0.089) −0.840 (0.185) 0.996 (0.067) 1.100 (0.098)
0.003 0.001 0.013 0.203 0.001 0.092 b0.001 0.027 0.024 0.039
* = Significant difference between pre-op and Post-1-year, Post-6-weeks and Post-1-year. ¥ = Significant difference between every time points. + = Significant difference between pre-op and Post-1-year. BW ∗ BH = Normalization of the joint moments to the product of body weight and body height. ADD = Adduction. ABD = Abduction. WA = Weight acceptance. Prop. = Propulsive.
Surgical
Non-Surgical
Flexion Angle (Deg)
75
*
70 65 60 55 50 Surgical
Non-Surgical
A) Hip Flexion Surgical
Non-Surgical
ABD Angle (Deg)
0 -1 -2 -3 -4 -5 -6 -7 -8 -9 -10
* B) Hip Abducon Surgical
Non-Surgical
Extension Moment (NM/kg)
1.2 1
*
0.8 0.6 0.4 0.2 0
C) Hip Extension Moment Fig. 2. Hip kinematics and kinetics between limbs independent of time during stair ascent. The * indicates a significant difference between the surgical and non-surgical limbs. A) Hip flexion, B) hip abduction and C) hip extension moments.
initial increase in hip flexion on the surgical limb that was observed pre-operatively may be due to increased forward trunk lean in order to propel the body forward while ascending the stairs which may have developed as a compensatory strategy due to the pain and disability associated with end stage hip osteoarthritis (Queen et al., 2013a). This compensatory action shifts the body's center of mass in a more forward position, thus accomplishing the task while reducing the joint compressive force on the affected hip. Decreased hip flexion seen one year after surgery may be indicative of improved strength and decreased pain resulting in a patients' willingness to use the surgical hip more while maintaining a more neutral trunk position. However, while the peak hip extension angle increased one year after surgery, the peak hip extension value indicated that these patients were still in a small degree of hip flexion during stair climbing, whereas healthy control subjects usually ascend the stairs with some hip extension at the end of the stance phase (Lamontagne et al., 2011; Nadeau et al., 2003; Protopapadaki et al., 2007; Shrader et al., 2009). This suggests that despite improvements in stair climbing mechanics, THA patients do not achieve the same level of hip extension as healthy individuals and as a result are still using compensatory strategies during stair climbing potentially as a result of persistent extensor mechanism weakness or mobility limitations (Queen et al., 2013a; Shrader et al., 2009). Side-to-side differences in lower extremity mechanics continue to persist up to 1 year following THA, as hypothesized. Although significant differences were observed across time for both the surgical and nonsurgical limbs, the non-surgical side was still being used more than the surgical side, indicated by the decreased peak hip flexion and abduction angles and peak hip extension moment on the non-surgical side. Previous literature has indicated that the internal extension moment correlates with the activation of the extensor mechanism during stair ascent in order to make this step transition (McFadyen and Winter, 1988). Therefore, the asymmetrical side-to-side peak extension moments reported in this study highlight the inability, even one year following surgery, of the extensor mechanism to achieve the normal extension moments bilaterally that are required during stair negotiation (Queen et al., 2013a). It is no surprise that deficits in the hip abduction angle on the surgical limb were also noted in comparison with the non-surgical limb, a finding that has previously been reported in this patient population during level walking (Shrader et al., 2009). Previous literature has indicated the importance of the hip abductors in controlling lateral pelvic obliquity and for raising the pelvis on the contralateral side in order to acquire sufficient lateral elevation so that the swing leg can successfully avoid the intermediate step (Nadeau et al., 2003). In addition, previous work
Please cite this article as: Queen, R.M., et al., Bilateral symmetry in lower extremity mechanics during stair ascent and descent following a total hip arthroplasty: A one-year longitudinal study, Clin. Biomech. (2014), http://dx.doi.org/10.1016/j.clinbiomech.2014.11.004
R.M. Queen et al. / Clinical Biomechanics xxx (2014) xxx–xxx
5
Table 2 Peak hip kinematics and kinetics across time independent of limb during stair descent. (Values reported as mean (standard error of the mean).)
Flexion (deg)* Extension (deg)* Adduction (deg) Abduction (deg) Flexion moment (BW ∗ BH)* Extension moment (BW ∗ BH) ADD moment (BW ∗ BH)* ABD moment (BW ∗ BH)¥ WA vertical GRF (BW)* Prop. vertical GRF (BW)*
Pre-op
6-weeks post-op
1-year post-op
P value
34.3 (8.9) 19.1 (8.5) 5.4 (4.8) −2.3 (4.3) 0.390 (0.234) −0.266 (0.319) 0.099 (0.055) −0.880 (0.277) 1.19 (0.21) 0.93 (0.05)
32.1 (9.0) 16.9 (8.3) 6.1 (4.0) −2.6 (3.2) 0.418 (0.324) −0.286 (0.252) 0.105 (0.072) −0.982 (0.256) 1.26 (0.27) 0.94 (0.08)
25.6 (8.0) 11.2 (7.2) 6.5 (4.2) −2.7 (3.6) 0.594 (0.557) −0.323 (0.300) 0.138 (0.077) −1.025 (0.222) 1.35 (0.16) 0.89 (0.08)
b0.001 b0.001 0.076 0.842 0.007 0.298 0.004 b0.001 b0.001 b0.001
* = Significant difference between pre-op and Post-1-year, Post-6-weeks and Post-1-year. ¥ = Significant difference between pre-op and Post-6-weeks, pre-op and Post-1-year. BW ∗ BH = Normalization of the joint moments to the product of body weight and body height. ADD = Adduction. ABD = Abduction. WA = Weight acceptance. Prop. = Propulsion.
in this patient population indicated that these patients demonstrated distal compensations, notably on the contralateral limb, to account for the limited hip motion in order to climb the stairs (Lamontagne et al., 2011). Further research is warranted to understand the residual effects that compensatory mechanics at the affected joint could have on adjacent joints and the potential for joint damage at these joints. This may result from increased loading and motion in order to compensate for limitations in motion at the surgical joint. The differences observed during stair descending were very similar to those reported for stair ascending with the THA patients demonstrating a more symmetrical movement pattern with an improved range of motion by one year post-operatively (Protopapadaki et al., 2007). The ability of our THA patients to achieve a peak hip flexion moment similar to healthy controls is indicative of improved muscle activation of the extensor mechanism. On the contrary, while the peak hip flexion and extension angles found in our patients were similar to those found in previous hip replacement populations during stair descent (Queen et al., 2013a), these values still did not reach those associated with healthy controls, indicating that these patients were still using compensatory strategies during stair descent. A significant side-to-side asymmetry continued to persist in the peak hip abduction moment, even one year following surgery. When the foot strikes the stair below, the abductors must generate a moment with enough magnitude to sustain the body weight as it is transferred medially to the stance limb (Kirkwood et al., 1999). This prevents the drop of the contralateral pelvis, thus potentially
playing a pivotal role in maintaining balance and stability (Jacquelin Perry, 1992). Therefore, abductor weakness, present following a THA, could play a crucial role in the functional limitations experienced by this patient population while performing more difficult daily tasks that require more strength and stability during single leg stance. One of the limitations of this study is the small sample size. Although there was sufficient power to detect side-to-side differences it is possible that additional biomechanical differences could be observed with an increase in the sample size. In addition, no healthy control data was collected as part of this study. As a result, our subject data was compared to normative values reported previously in the literature. The lack of standardized methods, such as stair dimensions, results in difficult comparisons of stair climbing data across studies. In addition, the use of skin based motion capture techniques introduces some soft tissue artifact which cannot be avoided and is a known limitation of this type of data collection. Finally, the operations performed as part of this study were not completed by a single surgeon and more than one surgical implant was used. Differences in surgical experience and implant could have altered patient function following surgery, however, limited information exists in the literature to support the idea that implant and surgeon would alter lower extremity mechanics following THA. Conclusions The asymmetries reported in this study that could have resulted from abductor and extensor weakness are more noticeable during stair ascending and descending due to the increased demands placed on these muscle groups during stair climbing when compared
Surgical
Non-Surgical
1.8 1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 0 Pre
6 weeks
1 year
Fig. 3. Changes across time and between limbs for weight acceptance GRF during stair ascent.
Please cite this article as: Queen, R.M., et al., Bilateral symmetry in lower extremity mechanics during stair ascent and descent following a total hip arthroplasty: A one-year longitudinal study, Clin. Biomech. (2014), http://dx.doi.org/10.1016/j.clinbiomech.2014.11.004
6
R.M. Queen et al. / Clinical Biomechanics xxx (2014) xxx–xxx
with level walking. These abnormal movement patterns on the surgical limb could be the result of either the patients' inability or reluctance to utilize the affected hip; nevertheless, the increased demand on other joints may lead to long term joint wear and pain. Based on the results of this study, future work should examine whether the addition of a focused physical therapy intervention could decrease the side-to-side asymmetries and restore more normal function in this patient population. The addition of more dynamic and demanding tasks needs to be considered when assessing post-operative physical function as the patients receiving THA continue to place more demand on these implants through increasing activity. The side-to-side differences in joint mechanics reported in this study should potentially be addressed during the early post-operative period through additional interventions in an attempt to normalize the differences and potentially improve long-term joint health throughout the lower extremity. References Arden, N., Nevitt, M.C., 2006. Osteoarthritis: epidemiology. Best Pract. Res. Clin. Rheumatol. 20, 3–25. Beaulieu, M.L., Lamontagne, M., Beaule, P.E., 2010. Lower limb biomechanics during gait do not return to normal following total hip arthroplasty. Gait Posture 32, 269–273. Berend, K.R., Lombardi, A.V., Mallory, T.H., Dodds, K.L., Adams, J.B., 2004. Cementless double-tapered total hip arthroplasty in patients 75 years of age and older. J. Arthroplast. 19, 288–295. Bergmann, G., Deuretzbacher, G., Heller, M., Graichen, F., Rohlmann, A., Strauss, J., Duda, G.N., 2001. Hip contact forces and gait patterns from routine activities. J. Biomech. 34, 859–871. Costigan, P.A., Deluzio, K.J., Wyss, U.P., 2002. Knee and hip kinetics during normal stair climbing. 16, 31–37. Croft, P., Lewis, M., Wynn Jones, C., Coggon, D., Cooper, C., 2002. Health status in patients awaiting hip replacement for osteoarthritis. Rheumatology 41, 1001–1007. Espehaug, B., Havelin, L.I., Engesaeter, L.B., Langeland, N., Vollset, S.E., 1998. Patient satisfaction and function after primary and revision total hip replacement. Clin. Orthop. Relat. Res. 135–148. Hicks-Little, C.A., Peindl, R.D., Hubbard, T.J., Scannell, B.P., Springer, B.D., Odum, S.M., Fehring, T.K., Cordova, M.L., 2011. Lower extremity joint kinematics during stair climbing in knee osteoarthritis. Med. Sci. Sports Exerc. 43, 516–524. Isobe, Y., Okuno, M., Otsuki, T., Yamamoto, K., 1998. Clinical study on arthroplasties for osteoarthritic hip by quantitative gait analysis. Comparison between total hip arthroplasty and bipolar endoprosthetic arthroplasty. Biomed. Mater. Eng. 8, 167–175. Jacquelin Perry, B.S., 1992. Gait Analysis: Normal and Pathological Function. Slack Incorporated. Jones, C.A., Voaklander, D.C., Johnston, D.W., Suarez-Almazor, M.E., 2001. The effect of age on pain, function, and quality of life after total hip and knee arthroplasty. Arch. Intern. Med. 161, 454–460. JRH, F., 2011. Total Hip Replacement. American Academy of Orthopaedic Surgeons. Kiebzak, G.M., Vain, P.A., Gregory, A.M., Mokris, J.G., Mauerhan, D.R., 1997. SF-36 general health status survey to determine patient satisfaction at short-term follow-up after total hip and knee arthroplasty. J. South. Orthop. Assoc. 6, 169–172. Kirkwood, R.N., Culham, E.G., Costigan, P., 1999. Hip moments during level walking, stair climbing, and exercise in individuals aged 55 years or older. Phys. Ther. 79, 360–370. Lamontagne, M., Beaulieu, M.L., Beaule, P.E., 2011. Comparison of joint mechanics of both lower limbs of THA patients with healthy participants during stair ascent and descent. J. Orthop. Res. 29, 305–311. Laupacis, A., Bourne, R., Rorabeck, C., Feeny, D., Wong, C., Tugwell, P., Leslie, K., Bullas, R., 1993. The effect of elective total hip replacement on health-related quality of life. J. Bone Joint Surg. Am. 75, 1619–1626.
Lawrence, R.C., Felson, D.T., Helmick, C.G., Arnold, L.M., Choi, H., Deyo, R.A., Gabriel, S., Hirsch, R., Hochberg, M.C., Hunder, G.G., Jordan, J.M., Katz, J.N., Kremers, H.M., Wolfe, F., National Arthritis Data, W., 2008. Estimates of the prevalence of arthritis and other rheumatic conditions in the United States. Part II. Arthritis Rheum. 58, 26–35. Loizeau, J., Allard, P., Duhaime, M., Landjerit, B., 1995. Bilateral gait patterns in subjects fitted with a total hip prosthesis. Arch. Phys. Med. Rehabil. 76, 552–557. McCrory, J.L., White, S.C., Lifeso, R.M., 2001. Vertical ground reaction forces: objective measures of gait following hip arthroplasty. Gait Posture 14, 104–109. McFadyen, B.J., Winter, D.A., 1988. An integrated biomechanical analysis of normal stair ascent and descent. J. Biomech. 21, 733–744. Miki, H., Sugano, N., Hagio, K., Nishii, T., Kawakami, H., Kakimoto, A., Nakamura, N., Yoshikawa, H., 2004. Recovery of walking speed and symmetrical movement of the pelvis and lower extremity joints after unilateral THA. J. Biomech. 37, 443–455. Montin, L., Leino-Kilpi, H., Suominen, T., Lepisto, J., 2008. A systematic review of empirical studies between 1966 and 2005 of patient outcomes of total hip arthroplasty and related factors. J. Clin. Nurs. 17, 40–45. Nadeau, S., McFadyen, B.J., Malouin, F., 2003. Frontal and sagittal plane analyses of the stair climbing task in healthy adults aged over 40 years: what are the challenges compared to level walking? Clin. Biomech. 18, 950–959. Ogonda, L., Wilson, R., Archbold, P., Lawlor, M., Humphreys, P., O'Brien, S., Beverland, D., 2005. A minimal-incision technique in total hip arthroplasty does not improve early postoperative outcomes. A prospective, randomized, controlled trial. J. Bone Joint Surg. Am. 87, 701–710. Protopapadaki, A., Drechsler, W.I., Cramp, M.C., Coutts, F.J., Scott, O.M., 2007. Hip, knee, ankle kinematics and kinetics during stair ascent and descent in healthy young individuals. Clin. Biomech. 22, 203–210. Queen, R.M., Butler, R.J., Watters, T.S., Kelley, S.S., Attarian, D.E., Bolognesi, M.P., 2011a. The effect of total hip arthroplasty surgical approach on postoperative gait mechanics. J. Arthroplasty 26, 66–71. Queen, R.M., Watters, T.S., Abbey, A.N., Sabesan, V.J., Vail, T.P., Bolognesi, M.P., 2011b. Gait symmetry: a comparison of hip resurfacing and jumbo head total hip arthroplasty patients. J. Arthroplasty 26, 680–685. Queen, R.M., Newman, E.T., Abbey, A.N., Vail, T.P., Bolognesi, M.P., 2013a. Stair ascending and descending in hip resurfacing and large head total hip arthroplasty patients. J. Arthroplast. 28, 684–689. Queen, R.M., Schaeffer, J.F., Butler, R.J., Berasi, C.C., Kelley, S.S., Attarian, D.E., Bolognesi, M.P., 2013b. Does surgical approach during total hip arthroplasty alter gait recovery during the first year following surgery? J. Arthroplast. 28, 1639–1643. Queen, R.M., Appleton, J.S., Butler, R.J., Newman, E.T., Kelley, S.S., Attarian, D.E., Bolognesi, M.P., 2014. Total hip arthroplasty surgical approach does not alter postoperative gait mechanics one year after surgery. PM R 6, 221–226 (quiz 226). Reardon, K., Galea, M., Dennett, X., Choong, P., Byrne, E., 2001. Quadriceps muscle wasting persists 5 months after total hip arthroplasty for osteoarthritis of the hip: a pilot study. Intern. Med. J. 31, 7–14. Shih, C.H., Du, Y.K., Lin, Y.H., Wu, C.C., 1994. Muscular recovery around the hip joint after total hip arthroplasty. Clin. Orthop. Relat. Res. 115–120. Shrader, M.W., Bhowmik-Stoker, M., Jacofsky, M.C., Jacofsky, D.J., 2009. Gait and stair function in total and resurfacing hip arthroplasty: a pilot study. Clin. Orthop. Relat. Res. 467, 1476–1484. Talis, V.L., Grishin, A.A., Solopova, I.A., Oskanyan, T.L., Belenky, V.E., Ivanenko, Y.P., 2008. Asymmetric leg loading during sit-to-stand, walking and quiet standing in patients after unilateral total hip replacement surgery. Clin. Biomech. 23, 424–433. Unver, B., Ertekin, O., Karatosun, V., 2014. Pain, fear of falling and stair climbing ability in patients with knee osteoarthritis before and after knee replacement: 6 month follow-up study. J. Musculoskelet. Rehabil. 27, 77–84. Whitchelo, T., McClelland, J.A., Webster, K.E., 2014. Factors associated with stair climbing ability in patients with knee osteoarthritis and knee arthroplasty: a systematic review. Disabil. Rehabil. 36 (13), 1051–1060.
Please cite this article as: Queen, R.M., et al., Bilateral symmetry in lower extremity mechanics during stair ascent and descent following a total hip arthroplasty: A one-year longitudinal study, Clin. Biomech. (2014), http://dx.doi.org/10.1016/j.clinbiomech.2014.11.004
