99 C OPYRIGHT 2015
BY
T HE J OURNAL
OF
B ONE
AND J OINT
S URGERY, I NCORPORATED
A commentary by Tobin T. Eckel, MD, and Scott B. Shawen, MD, is linked to the online version of this article at jbjs.org.
Isolated Gastrocnemius Recession for Achilles Tendinopathy: Strength and Functional Outcomes Deborah A. Nawoczenski, PT, PhD, Heather Barske, MD, FRCSC, Joshua Tome, MS, Laura K. Dawson, DO, Jason P. Zlotnicki, BS, and Benedict F. DiGiovanni, MD Investigation performed at the former Movement Analysis Laboratory and Center for Foot and Ankle Research, Rochester Center, Ithaca College, Rochester, New York
Background: Gastrocnemius recession has emerged as a viable intervention for patients with recalcitrant foot and ankle disorders associated with isolated gastrocnemius contracture. The purpose of this case-control study was to investigate the effects of an isolated gastrocnemius recession on pain, patient-reported function, and strength in patients with chronic Achilles tendinopathy and an isolated gastrocnemius contracture. Methods: Thirteen patients with unilateral Achilles tendinopathy (mean age [and standard deviation], fifty-two ± 7.7 years) who received a gastrocnemius recession and ten matched-control subjects participated. A visual analog scale was used to assess pain, and the Foot and Ankle Ability Measure was used to evaluate patient-reported function in activities of daily living and sports. Patients were asked about their satisfaction with the results of the gastrocnemius recession. Ankle plantar flexion peak torque was assessed at 60/sec and 120/sec. Appropriate t tests were used to assess limb symmetry and strength differences between the groups. Results: The mean duration of follow-up was eighteen months (range, twelve to twenty-eight months). Gastrocnemius recession provided significant pain relief (mean preoperative visual analog scale score [and standard deviation], 6.8 ± 1.8; mean follow-up visual analog scale score, 1.4 ± 2.7; p < 0.05). Foot and Ankle Ability Measure outcomes showed between-group differences in activities of daily living (Achilles tendinopathy group, 89.7; control group, 98.5; p = 0.05) and sports subscales (Achilles tendinopathy group, 71.9; control group, 95.1; p = 0.05). The activities reported to be the most challenging included going up hills, climbing stairs, running, and jumping. Eleven of the thirteen patients in the Achilles tendon group were satisfied with treatment. Side-to-side strength comparisons showed no differences at 60/sec. Significant differences were observed at 120/sec (Achilles tendinopathy group, 21%; control group, 3%; p < 0.05); however, the involved limb reached a peak torque similar to that in the control limb. Conclusions: Isolated gastrocnemius recession provides significant and sustained pain relief for chronic Achilles tendinopathy. Good function can be expected for activities of daily living, but power and endurance activities were more problematic for the Achilles tendinopathy group. Isokinetic strength assessment may not effectively capture patientreported functional deficits. Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.
Peer Review: This article was reviewed by the Editor-in-Chief and one Deputy Editor, and it underwent blinded review by two or more outside experts. It was also reviewed by an expert in methodology and statistics. The Deputy Editor reviewed each revision of the article, and it underwent a final review by the Editor-in-Chief prior to publication. Final corrections and clarifications occurred during one or more exchanges between the author(s) and copyeditors.
Disclosure: One or more of the authors received payments or services, either directly or indirectly (i.e., via his or her institution), from a third party in support of an aspect of this work. None of the authors, or their institution(s), have had any financial relationship, in the thirty-six months prior to submission of this work, with any entity in the biomedical arena that could be perceived to influence or have the potential to influence what is written in this work. In addition, no author has had any other relationships, or has engaged in any other activities, that could be perceived to influence or have the potential to influence what is written in this work. The complete Disclosures of Potential Conflicts of Interest submitted by authors are always provided with the online version of the article.
J Bone Joint Surg Am. 2015;97:99-105
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http://dx.doi.org/10.2106/JBJS.M.01424
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A
chilles tendinopathy is a common foot and ankle disorder1-5, and its overall prevalence in adults is estimated to be 2.35 per 10001,6. Achilles tendinopathy involves midportion tendon and paratendon conditions of the Achilles as well as insertional tendon abnormalities4,7. Achilles tendinopathy is characterized by persistent localized pain, swelling, reduced plantar flexion strength and dorsiflexion motion, and impaired function4,6,8-10. The etiology of Achilles tendinopathy is unclear. However, mechanical overload leading to cumulative microtrauma is regarded as the main pathological stimulus11,12. Current evidence has identified limitations in ankle dorsiflexion associated with an isolated gastrocnemius contracture as one of the key impairments linked to the chronicity of pain and dysfunction in certain foot and ankle disorders, including Achilles tendinopathy13-25. Over the past decade, the increased recognition of an isolated gastrocnemius contracture in patients with musculoskeletal impairment15,16,22 has created interest in shifting the focus from directly debriding the Achilles tendon to selectively reducing tension on the tendon through the use of a gastrocnemius recession procedure17,19-21,26-30. A common gastrocnemius recession procedure is the Strayer procedure23, which is the selective release of the gastrocnemius fascia at the musclefascia confluence. While theorized to unload the Achilles tendon and reduce pain, this procedure may also modulate the loss of strength that may accompany traditional surgical approaches, including Achilles tendon-lengthening procedures7,17,27,29,31-33. The findings of small, uncontrolled case-series studies on outcomes following gastrocnemius recession for chronic foot problems associated with a gastrocnemius equinus contracture are encouraging23,27,29,34. The reports have indicated fewer postoperative complications, shortened recovery time, and earlier return to work compared with traditional surgical management23,27,29,34. Investigators have reported good patient satisfaction, substantial pain reduction, and restoration of dorsiflexion21,23,24,27,29. However, validated outcome measures assessing the potential impact on myotendinous structures and patients’ self-reported function have been only minimally explored13,35,36. Additionally, comparisons among study outcomes are challenging because of the inclusion of patients with a variety of pathological conditions and the use of concomitant reconstructive procedures with the gastrocnemius recession13,18,27,29,35. The purpose of this study was to investigate the effects of an isolated gastrocnemius recession on pain, patient-reported function, and muscle strength in patients with recalcitrant Achilles tendinopathy and an isolated gastrocnemius contracture. With use of a validated outcome tool and a control group, we report on plantar flexion strength and functional outcomes in a homogeneous cohort of patients who were similar with regard to entry disorder (Achilles tendinopathy) and entry point (failed nonoperative intervention of at least six months’ duration) and who were without concomitant surgical procedures.
I S O L AT E D G A S T R O C N E M I U S R E C E S S I O N F O R A C H I L L E S T E N D I N O PAT H Y : S T R E N G T H A N D F U N C T I O N A L O U T C O M E S
ords of individuals who sought professional outpatient consultation from foot and ankle orthopaedic surgeons at the University of Rochester Medical Center for recalcitrant Achilles tendinopathy (of at least six months’ duration) and who were managed with a gastrocnemius recession (Strayer procedure) from December 2008 through December 2010. Of nineteen patients managed with an isolated gastrocnemius recession procedure for Achilles tendinopathy, fourteen were available for follow-up evaluation, one declined to participate, and four could not be reached by telephone. One of the fourteen available for follow-up had an incomplete data set and was therefore excluded from the analysis. Subjects in the Achilles tendinopathy group (n = thirteen) were included if they met all four eligibility criteria. Eligible subjects had (1) an isolated gastrocnemius contracture (a positive Silfverski¨old test with 10 with the knee flexed) and had (2) a diagnosis of unilateral insertional or noninsertional Achilles tendinopathy. Achilles tendinopathy was clinically diagnosed through palpation, with tenderness and swelling noted along the Achilles tendon. For insertional Achilles tendinopathy, these findings are typically at the insertion on the calcaneus. For noninsertional Achilles tendinopathy, this is typically located 2 to 6 cm proximal to the insertion. In addition, eligible subjects had (3) failed a minimum of six months of conservative treatment that included nonsteroidal anti-inflammatory drugs, heel lifts, and physical therapy, and they also had (4) no concomitant procedures. Consistent with the standard of care, the majority of patients presenting with Achilles tendinopathy were managed nonoperatively. Subjects were excluded if they had prior surgery on the ipsilateral and/or contralateral Achilles tendon or plantar fascia, spastic contracture secondary to neurological injury, or surgery or disease involving the leg that would limit range of motion of the ankle. A minimum period of six months following the gastrocnemius recession procedure and a return to full activity were required prior to testing. The control subjects (n = 10) were recruited from the general population and were matched for age and body mass index. Similar exclusion criteria to those used for the Achilles tendinopathy group were used for the control group. Table I provides demographic and clinical variables for all subjects. Institutional review board approval was received, and an informed consent form approved by the University of Rochester and Ithaca College was signed by participants prior to participation. Data collection took place at the Movement Analysis Laboratory and the Center for Foot and Ankle Research at the Rochester Center of Ithaca College.
Surgical and Postoperative Protocol Two fellowship-trained orthopaedic foot and ankle surgeons (B.F.D. and another surgeon) performed the gastrocnemius recession with use of the Strayer procedure. With the patient prone, the gastrocnemius and soleus fascial layers are separated just distal to the gastrocnemius muscle-fascia confluence. The gastrocnemius fascia is sectioned just distal to the musculotendinous junction to minimize disruption to the soleus fascia and muscle. The proximal gastrocnemius tendon is then sutured back to the underlying soleus fascia. Achilles tendinopathy subjects’ affected leg was immobilized in a short leg plaster cast and partial weight-bearing was permitted. At five to seven days postoperatively, the leg was transitioned to a walking boot. Patients were allowed to walk as tolerated and were instructed to wear the boot for activities outside the home. They were encouraged to perform Achilles tendon and gastrocnemius-stretching exercises and ankle motion exercises twice a day. The wound was checked three weeks postoperatively, and patients were encouraged to initiate a home program that included elastic-band ankle and footstrengthening and heel-raising exercises. They were instructed to start lowimpact exercise, including swimming, biking, and elliptical training. At six weeks postoperatively, patients were evaluated and cleared to participate in activities without restriction, with gradual resumption of low-impact weightbearing activities. Subjects were again evaluated at four and six months postoperatively and were discharged from physician care at that point. No formal physical therapy was prescribed.
Materials and Methods Subjects
Pain, Patient-Reported Function, and Satisfaction
T
Pain was measured as part of clinical care at the time of treatment. Preoperative and postoperative pain data were acquired with use of a 10-cm numeric pain
wenty-three participants between thirty-five and sixty-five years of age were included in this retrospective cohort study. We reviewed the medical rec-
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rating visual analog scale (VAS), on which 0 indicates no pain and 10 indicates the worst pain imaginable. The Foot and Ankle Ability Measure (FAAM) was used to assess patient-reported level of function. This region-specific instrument has a twenty-one-item activities-of-daily living subscale and an 9,38 eight-item sports subscale . Higher scores represent higher levels of function. Evidence to support the Foot and Ankle Ability Measure has been demonstrated for content and construct validity, reliability, and responsive9,13,38 ness . Although a validated tool was not used, patients were asked to describe their satisfaction with the results from surgery by indicating whether they were totally satisfied, satisfied with minor reservations with the treatment, satisfied with major reservations with the treatment, or not satisfied with the treatment.
Strength-Testing The Biodex System 3 (Biodex Medical Systems, Shirley, New York) was used to measure isokinetic concentric ankle plantar flexion strength at 60/sec and 120/sec. These testing speeds were selected to capture ankle angular velocities 35 that may be linked to daily function, particularly gait and stair-climbing . Subjects’ legs were stabilized according to manufacturer guidelines for ankle plantar flexion. The knee was placed in 60 flexion. Three sets of five repetitions were completed at each speed, with appropriate rest between sets and test speeds. Subjects were given verbal encouragement to pull (dorsiflex) and push (plantar flex) “as fast and hard as possible” through the entire range of ankle motion. Data were collected in a randomized manner. Custom software was used to extract peak plantar flexion torque (Newton-meters), and the mean of the middle three repetitions of each set was entered into the analysis. A Limb Symmetry Index, defined as the difference in plantar flexion torque between the involved and uninvolved limbs and expressed as a percentage of strength deficit ([uninvolved limb – involved limb]/uninvolved limb · 100) was calculated for the Achilles tendinopathy subjects. For the control participants, the nondominant limb was compared with the dominant limb (defined as 39 the limb with peak plantar flexion torque output ). All torque data were normalized to body weight.
Analysis Ninety-five percent confidence intervals were created for the Foot and Ankle Ability Measure from the database of healthy control subjects to establish normative ranges for the activities of daily living and sports subscales against 13,35 which the Achilles tendinopathy subjects’ data were compared .
Fig. 1-A
I S O L AT E D G A S T R O C N E M I U S R E C E S S I O N F O R A C H I L L E S T E N D I N O PAT H Y : S T R E N G T H A N D F U N C T I O N A L O U T C O M E S
Isokinetic data were assessed for normality and variance homogeneity. If non-normal data were present, appropriate transformation methods were utilized. Paired t tests were used to examine side-to-side differences (involved and uninvolved or nondominant and dominant) for peak plantar flexion torque at testing speeds of 60/sec and 120/sec. Independent sample t tests were used to examine the difference in Limb Symmetry Index values between Achilles tendinopathy subjects and control subjects. Changes in magnitude were also compared between the involved limb of Achilles tendinopathy patients and the nondominant limb of control participants. 13 Sample size considerations were based on previous research investigating the effects of a gastrocnemius recession procedure on patient-reported outcomes with use of the validated Foot and Ankle Ability Measure assessment tool to determine power for our study. With use of an average standard deviation value of 6 for the function and global rating subscales of the Foot and Ankle Ability Measure, with a difference of 8 points considered a clinically meaningful 9 difference (estimates of reasonable effect size of 0.60) , a minimum of nine subjects per group was required to achieve 80% power (1 – b = 0.80). The threshold value for significance was set at p < 0.05. Statistical analysis was performed with use of statistical software (SPSS, version 18; SPSS, Chicago, Illinois).
Source of Funding This study was funded in part through a grant from the American Orthopaedic Foot & Ankle Society.
Results he Achilles tendinopathy group (mean age [and standard deviation, SD], fifty-two ± 7.7 years) was examined at a mean of eighteen months (range, twelve to twenty-eight months) after gastrocnemius recession. Ten subjects had insertional Achilles tendinopathy, and three subjects had noninsertional Achilles tendinopathy (Table I). Peak active dorsiflexion (knee in extension) was assessed at the time of follow-up. Dorsiflexion was greater in the involved limb than in the uninvolved limb of the Achilles tendinopathy group (17.6 and 13.3; p > 0.05).
T
Pain, Patient-Reported Outcomes, and Satisfaction The mean VAS pain score in the Achilles tendinopathy group was 6.8 (SD, 1.8) preoperatively, and it was 1.6 (SD, 2.3)
Fig. 1-B
Fig. 1-A Graph showing the mean values and 95% confidence intervals (CI) based on data from ten healthy control subjects for the Foot and Ankle Ability Measure activities of daily living (FAAM ADL) subscale. Data from the thirteen individual subjects with Achilles tendinopathy are also plotted. Fig. 1-B Mean values and 95% confidence intervals (CI) based on data from ten healthy control subjects for the Foot and Ankle Ability Measure (FAAM) sports subscale. Data from the thirteen individual subjects with Achilles tendinopathy are also plotted.
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postoperatively (p < 0.05). Significant differences were observed between groups for Foot and Ankle Ability Measure scores for both activities of daily living (Achilles tendinopathy group, 89.7; control group, 98.5; p < 0.05) and sports (Achilles tendinopathy group, 71.9; control, 95.1; p < 0.05) subscales. Ninety-five percent confidence intervals based on control subject data for Foot
I S O L AT E D G A S T R O C N E M I U S R E C E S S I O N F O R A C H I L L E S T E N D I N O PAT H Y : S T R E N G T H A N D F U N C T I O N A L O U T C O M E S
and Ankle Ability Measure subscales are plotted together with individual Achilles tendinopathy subject data (Fig. 1). For the activities of daily living, the majority in the Achilles tendinopathy group approached the lower bounds of the 95% confidence interval of the control subjects; however, fewer Achilles tendinopathy subjects approached the lower limits of the sports subscale.
Fig. 2-A
Fig. 2-B
Figs. 2-A and 2-B Isokinetic peak torque (mean and standard error) for Achilles tendinopathy and control groups at 60/sec (Fig. 2-A) and 120/sec (Fig. 2-B). An asterisk indicates significant side-to-side differences (p < 0.05). The Limb Symmetry Index (LSI) indicates percent side-to-side differences. There were no differences in peak torque between the involved limb of the Achilles tendinopathy (AT) group and the nondominant limb of the control group (CON) at either test speed.
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I S O L AT E D G A S T R O C N E M I U S R E C E S S I O N F O R A C H I L L E S T E N D I N O PAT H Y : S T R E N G T H A N D F U N C T I O N A L O U T C O M E S
TABLE I Demographics and Clinical Variables* Achilles Tendinopathy Group (N = 13) Sex (M:F)
Control Group (N = 10)
8:5
5:5
Age (yr)
52.1 ± 7.7
53.3 ± 3.3
Weight (kg)
88.3 ± 15.9
83.3 ± 15.6
Height (m)
1.7 ± 0.07
1.7 ± 0.10
Body mass index
(kg/m2)
30.1 ± 4.5
P Value
28.7 ± 4.1
Peak dorsiflexion AROM†‡ (deg) Involved or nondominant limb
17.6 ± 5.6
13.5 ± 4.5
Uninvolved or dominant limb
13.3 ± 7.3
14.6 ± 6.8
89.7 ± 8.7
98.5 ± 3.4
BY
T HE J OURNAL
OF
B ONE
AND J OINT
S URGERY, I NCORPORATED
A commentary by Tobin T. Eckel, MD, and Scott B. Shawen, MD, is linked to the online version of this article at jbjs.org.
Isolated Gastrocnemius Recession for Achilles Tendinopathy: Strength and Functional Outcomes Deborah A. Nawoczenski, PT, PhD, Heather Barske, MD, FRCSC, Joshua Tome, MS, Laura K. Dawson, DO, Jason P. Zlotnicki, BS, and Benedict F. DiGiovanni, MD Investigation performed at the former Movement Analysis Laboratory and Center for Foot and Ankle Research, Rochester Center, Ithaca College, Rochester, New York
Background: Gastrocnemius recession has emerged as a viable intervention for patients with recalcitrant foot and ankle disorders associated with isolated gastrocnemius contracture. The purpose of this case-control study was to investigate the effects of an isolated gastrocnemius recession on pain, patient-reported function, and strength in patients with chronic Achilles tendinopathy and an isolated gastrocnemius contracture. Methods: Thirteen patients with unilateral Achilles tendinopathy (mean age [and standard deviation], fifty-two ± 7.7 years) who received a gastrocnemius recession and ten matched-control subjects participated. A visual analog scale was used to assess pain, and the Foot and Ankle Ability Measure was used to evaluate patient-reported function in activities of daily living and sports. Patients were asked about their satisfaction with the results of the gastrocnemius recession. Ankle plantar flexion peak torque was assessed at 60/sec and 120/sec. Appropriate t tests were used to assess limb symmetry and strength differences between the groups. Results: The mean duration of follow-up was eighteen months (range, twelve to twenty-eight months). Gastrocnemius recession provided significant pain relief (mean preoperative visual analog scale score [and standard deviation], 6.8 ± 1.8; mean follow-up visual analog scale score, 1.4 ± 2.7; p < 0.05). Foot and Ankle Ability Measure outcomes showed between-group differences in activities of daily living (Achilles tendinopathy group, 89.7; control group, 98.5; p = 0.05) and sports subscales (Achilles tendinopathy group, 71.9; control group, 95.1; p = 0.05). The activities reported to be the most challenging included going up hills, climbing stairs, running, and jumping. Eleven of the thirteen patients in the Achilles tendon group were satisfied with treatment. Side-to-side strength comparisons showed no differences at 60/sec. Significant differences were observed at 120/sec (Achilles tendinopathy group, 21%; control group, 3%; p < 0.05); however, the involved limb reached a peak torque similar to that in the control limb. Conclusions: Isolated gastrocnemius recession provides significant and sustained pain relief for chronic Achilles tendinopathy. Good function can be expected for activities of daily living, but power and endurance activities were more problematic for the Achilles tendinopathy group. Isokinetic strength assessment may not effectively capture patientreported functional deficits. Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.
Peer Review: This article was reviewed by the Editor-in-Chief and one Deputy Editor, and it underwent blinded review by two or more outside experts. It was also reviewed by an expert in methodology and statistics. The Deputy Editor reviewed each revision of the article, and it underwent a final review by the Editor-in-Chief prior to publication. Final corrections and clarifications occurred during one or more exchanges between the author(s) and copyeditors.
Disclosure: One or more of the authors received payments or services, either directly or indirectly (i.e., via his or her institution), from a third party in support of an aspect of this work. None of the authors, or their institution(s), have had any financial relationship, in the thirty-six months prior to submission of this work, with any entity in the biomedical arena that could be perceived to influence or have the potential to influence what is written in this work. In addition, no author has had any other relationships, or has engaged in any other activities, that could be perceived to influence or have the potential to influence what is written in this work. The complete Disclosures of Potential Conflicts of Interest submitted by authors are always provided with the online version of the article.
J Bone Joint Surg Am. 2015;97:99-105
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http://dx.doi.org/10.2106/JBJS.M.01424
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A
chilles tendinopathy is a common foot and ankle disorder1-5, and its overall prevalence in adults is estimated to be 2.35 per 10001,6. Achilles tendinopathy involves midportion tendon and paratendon conditions of the Achilles as well as insertional tendon abnormalities4,7. Achilles tendinopathy is characterized by persistent localized pain, swelling, reduced plantar flexion strength and dorsiflexion motion, and impaired function4,6,8-10. The etiology of Achilles tendinopathy is unclear. However, mechanical overload leading to cumulative microtrauma is regarded as the main pathological stimulus11,12. Current evidence has identified limitations in ankle dorsiflexion associated with an isolated gastrocnemius contracture as one of the key impairments linked to the chronicity of pain and dysfunction in certain foot and ankle disorders, including Achilles tendinopathy13-25. Over the past decade, the increased recognition of an isolated gastrocnemius contracture in patients with musculoskeletal impairment15,16,22 has created interest in shifting the focus from directly debriding the Achilles tendon to selectively reducing tension on the tendon through the use of a gastrocnemius recession procedure17,19-21,26-30. A common gastrocnemius recession procedure is the Strayer procedure23, which is the selective release of the gastrocnemius fascia at the musclefascia confluence. While theorized to unload the Achilles tendon and reduce pain, this procedure may also modulate the loss of strength that may accompany traditional surgical approaches, including Achilles tendon-lengthening procedures7,17,27,29,31-33. The findings of small, uncontrolled case-series studies on outcomes following gastrocnemius recession for chronic foot problems associated with a gastrocnemius equinus contracture are encouraging23,27,29,34. The reports have indicated fewer postoperative complications, shortened recovery time, and earlier return to work compared with traditional surgical management23,27,29,34. Investigators have reported good patient satisfaction, substantial pain reduction, and restoration of dorsiflexion21,23,24,27,29. However, validated outcome measures assessing the potential impact on myotendinous structures and patients’ self-reported function have been only minimally explored13,35,36. Additionally, comparisons among study outcomes are challenging because of the inclusion of patients with a variety of pathological conditions and the use of concomitant reconstructive procedures with the gastrocnemius recession13,18,27,29,35. The purpose of this study was to investigate the effects of an isolated gastrocnemius recession on pain, patient-reported function, and muscle strength in patients with recalcitrant Achilles tendinopathy and an isolated gastrocnemius contracture. With use of a validated outcome tool and a control group, we report on plantar flexion strength and functional outcomes in a homogeneous cohort of patients who were similar with regard to entry disorder (Achilles tendinopathy) and entry point (failed nonoperative intervention of at least six months’ duration) and who were without concomitant surgical procedures.
I S O L AT E D G A S T R O C N E M I U S R E C E S S I O N F O R A C H I L L E S T E N D I N O PAT H Y : S T R E N G T H A N D F U N C T I O N A L O U T C O M E S
ords of individuals who sought professional outpatient consultation from foot and ankle orthopaedic surgeons at the University of Rochester Medical Center for recalcitrant Achilles tendinopathy (of at least six months’ duration) and who were managed with a gastrocnemius recession (Strayer procedure) from December 2008 through December 2010. Of nineteen patients managed with an isolated gastrocnemius recession procedure for Achilles tendinopathy, fourteen were available for follow-up evaluation, one declined to participate, and four could not be reached by telephone. One of the fourteen available for follow-up had an incomplete data set and was therefore excluded from the analysis. Subjects in the Achilles tendinopathy group (n = thirteen) were included if they met all four eligibility criteria. Eligible subjects had (1) an isolated gastrocnemius contracture (a positive Silfverski¨old test with 10 with the knee flexed) and had (2) a diagnosis of unilateral insertional or noninsertional Achilles tendinopathy. Achilles tendinopathy was clinically diagnosed through palpation, with tenderness and swelling noted along the Achilles tendon. For insertional Achilles tendinopathy, these findings are typically at the insertion on the calcaneus. For noninsertional Achilles tendinopathy, this is typically located 2 to 6 cm proximal to the insertion. In addition, eligible subjects had (3) failed a minimum of six months of conservative treatment that included nonsteroidal anti-inflammatory drugs, heel lifts, and physical therapy, and they also had (4) no concomitant procedures. Consistent with the standard of care, the majority of patients presenting with Achilles tendinopathy were managed nonoperatively. Subjects were excluded if they had prior surgery on the ipsilateral and/or contralateral Achilles tendon or plantar fascia, spastic contracture secondary to neurological injury, or surgery or disease involving the leg that would limit range of motion of the ankle. A minimum period of six months following the gastrocnemius recession procedure and a return to full activity were required prior to testing. The control subjects (n = 10) were recruited from the general population and were matched for age and body mass index. Similar exclusion criteria to those used for the Achilles tendinopathy group were used for the control group. Table I provides demographic and clinical variables for all subjects. Institutional review board approval was received, and an informed consent form approved by the University of Rochester and Ithaca College was signed by participants prior to participation. Data collection took place at the Movement Analysis Laboratory and the Center for Foot and Ankle Research at the Rochester Center of Ithaca College.
Surgical and Postoperative Protocol Two fellowship-trained orthopaedic foot and ankle surgeons (B.F.D. and another surgeon) performed the gastrocnemius recession with use of the Strayer procedure. With the patient prone, the gastrocnemius and soleus fascial layers are separated just distal to the gastrocnemius muscle-fascia confluence. The gastrocnemius fascia is sectioned just distal to the musculotendinous junction to minimize disruption to the soleus fascia and muscle. The proximal gastrocnemius tendon is then sutured back to the underlying soleus fascia. Achilles tendinopathy subjects’ affected leg was immobilized in a short leg plaster cast and partial weight-bearing was permitted. At five to seven days postoperatively, the leg was transitioned to a walking boot. Patients were allowed to walk as tolerated and were instructed to wear the boot for activities outside the home. They were encouraged to perform Achilles tendon and gastrocnemius-stretching exercises and ankle motion exercises twice a day. The wound was checked three weeks postoperatively, and patients were encouraged to initiate a home program that included elastic-band ankle and footstrengthening and heel-raising exercises. They were instructed to start lowimpact exercise, including swimming, biking, and elliptical training. At six weeks postoperatively, patients were evaluated and cleared to participate in activities without restriction, with gradual resumption of low-impact weightbearing activities. Subjects were again evaluated at four and six months postoperatively and were discharged from physician care at that point. No formal physical therapy was prescribed.
Materials and Methods Subjects
Pain, Patient-Reported Function, and Satisfaction
T
Pain was measured as part of clinical care at the time of treatment. Preoperative and postoperative pain data were acquired with use of a 10-cm numeric pain
wenty-three participants between thirty-five and sixty-five years of age were included in this retrospective cohort study. We reviewed the medical rec-
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rating visual analog scale (VAS), on which 0 indicates no pain and 10 indicates the worst pain imaginable. The Foot and Ankle Ability Measure (FAAM) was used to assess patient-reported level of function. This region-specific instrument has a twenty-one-item activities-of-daily living subscale and an 9,38 eight-item sports subscale . Higher scores represent higher levels of function. Evidence to support the Foot and Ankle Ability Measure has been demonstrated for content and construct validity, reliability, and responsive9,13,38 ness . Although a validated tool was not used, patients were asked to describe their satisfaction with the results from surgery by indicating whether they were totally satisfied, satisfied with minor reservations with the treatment, satisfied with major reservations with the treatment, or not satisfied with the treatment.
Strength-Testing The Biodex System 3 (Biodex Medical Systems, Shirley, New York) was used to measure isokinetic concentric ankle plantar flexion strength at 60/sec and 120/sec. These testing speeds were selected to capture ankle angular velocities 35 that may be linked to daily function, particularly gait and stair-climbing . Subjects’ legs were stabilized according to manufacturer guidelines for ankle plantar flexion. The knee was placed in 60 flexion. Three sets of five repetitions were completed at each speed, with appropriate rest between sets and test speeds. Subjects were given verbal encouragement to pull (dorsiflex) and push (plantar flex) “as fast and hard as possible” through the entire range of ankle motion. Data were collected in a randomized manner. Custom software was used to extract peak plantar flexion torque (Newton-meters), and the mean of the middle three repetitions of each set was entered into the analysis. A Limb Symmetry Index, defined as the difference in plantar flexion torque between the involved and uninvolved limbs and expressed as a percentage of strength deficit ([uninvolved limb – involved limb]/uninvolved limb · 100) was calculated for the Achilles tendinopathy subjects. For the control participants, the nondominant limb was compared with the dominant limb (defined as 39 the limb with peak plantar flexion torque output ). All torque data were normalized to body weight.
Analysis Ninety-five percent confidence intervals were created for the Foot and Ankle Ability Measure from the database of healthy control subjects to establish normative ranges for the activities of daily living and sports subscales against 13,35 which the Achilles tendinopathy subjects’ data were compared .
Fig. 1-A
I S O L AT E D G A S T R O C N E M I U S R E C E S S I O N F O R A C H I L L E S T E N D I N O PAT H Y : S T R E N G T H A N D F U N C T I O N A L O U T C O M E S
Isokinetic data were assessed for normality and variance homogeneity. If non-normal data were present, appropriate transformation methods were utilized. Paired t tests were used to examine side-to-side differences (involved and uninvolved or nondominant and dominant) for peak plantar flexion torque at testing speeds of 60/sec and 120/sec. Independent sample t tests were used to examine the difference in Limb Symmetry Index values between Achilles tendinopathy subjects and control subjects. Changes in magnitude were also compared between the involved limb of Achilles tendinopathy patients and the nondominant limb of control participants. 13 Sample size considerations were based on previous research investigating the effects of a gastrocnemius recession procedure on patient-reported outcomes with use of the validated Foot and Ankle Ability Measure assessment tool to determine power for our study. With use of an average standard deviation value of 6 for the function and global rating subscales of the Foot and Ankle Ability Measure, with a difference of 8 points considered a clinically meaningful 9 difference (estimates of reasonable effect size of 0.60) , a minimum of nine subjects per group was required to achieve 80% power (1 – b = 0.80). The threshold value for significance was set at p < 0.05. Statistical analysis was performed with use of statistical software (SPSS, version 18; SPSS, Chicago, Illinois).
Source of Funding This study was funded in part through a grant from the American Orthopaedic Foot & Ankle Society.
Results he Achilles tendinopathy group (mean age [and standard deviation, SD], fifty-two ± 7.7 years) was examined at a mean of eighteen months (range, twelve to twenty-eight months) after gastrocnemius recession. Ten subjects had insertional Achilles tendinopathy, and three subjects had noninsertional Achilles tendinopathy (Table I). Peak active dorsiflexion (knee in extension) was assessed at the time of follow-up. Dorsiflexion was greater in the involved limb than in the uninvolved limb of the Achilles tendinopathy group (17.6 and 13.3; p > 0.05).
T
Pain, Patient-Reported Outcomes, and Satisfaction The mean VAS pain score in the Achilles tendinopathy group was 6.8 (SD, 1.8) preoperatively, and it was 1.6 (SD, 2.3)
Fig. 1-B
Fig. 1-A Graph showing the mean values and 95% confidence intervals (CI) based on data from ten healthy control subjects for the Foot and Ankle Ability Measure activities of daily living (FAAM ADL) subscale. Data from the thirteen individual subjects with Achilles tendinopathy are also plotted. Fig. 1-B Mean values and 95% confidence intervals (CI) based on data from ten healthy control subjects for the Foot and Ankle Ability Measure (FAAM) sports subscale. Data from the thirteen individual subjects with Achilles tendinopathy are also plotted.
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postoperatively (p < 0.05). Significant differences were observed between groups for Foot and Ankle Ability Measure scores for both activities of daily living (Achilles tendinopathy group, 89.7; control group, 98.5; p < 0.05) and sports (Achilles tendinopathy group, 71.9; control, 95.1; p < 0.05) subscales. Ninety-five percent confidence intervals based on control subject data for Foot
I S O L AT E D G A S T R O C N E M I U S R E C E S S I O N F O R A C H I L L E S T E N D I N O PAT H Y : S T R E N G T H A N D F U N C T I O N A L O U T C O M E S
and Ankle Ability Measure subscales are plotted together with individual Achilles tendinopathy subject data (Fig. 1). For the activities of daily living, the majority in the Achilles tendinopathy group approached the lower bounds of the 95% confidence interval of the control subjects; however, fewer Achilles tendinopathy subjects approached the lower limits of the sports subscale.
Fig. 2-A
Fig. 2-B
Figs. 2-A and 2-B Isokinetic peak torque (mean and standard error) for Achilles tendinopathy and control groups at 60/sec (Fig. 2-A) and 120/sec (Fig. 2-B). An asterisk indicates significant side-to-side differences (p < 0.05). The Limb Symmetry Index (LSI) indicates percent side-to-side differences. There were no differences in peak torque between the involved limb of the Achilles tendinopathy (AT) group and the nondominant limb of the control group (CON) at either test speed.
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I S O L AT E D G A S T R O C N E M I U S R E C E S S I O N F O R A C H I L L E S T E N D I N O PAT H Y : S T R E N G T H A N D F U N C T I O N A L O U T C O M E S
TABLE I Demographics and Clinical Variables* Achilles Tendinopathy Group (N = 13) Sex (M:F)
Control Group (N = 10)
8:5
5:5
Age (yr)
52.1 ± 7.7
53.3 ± 3.3
Weight (kg)
88.3 ± 15.9
83.3 ± 15.6
Height (m)
1.7 ± 0.07
1.7 ± 0.10
Body mass index
(kg/m2)
30.1 ± 4.5
P Value
28.7 ± 4.1
Peak dorsiflexion AROM†‡ (deg) Involved or nondominant limb
17.6 ± 5.6
13.5 ± 4.5
Uninvolved or dominant limb
13.3 ± 7.3
14.6 ± 6.8
89.7 ± 8.7
98.5 ± 3.4
