The Journal of Arthroplasty xxx (2015) xxx–xxx
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Total Hip Arthroplasty for Failed Internal Fixation After Femoral Neck Fracture Versus That for Acute Displaced Femoral Neck Fracture: A Comparative Study Zhouyuan Yang, MM a, Huifang Liu, MD b, Xiaowei Xie, MD a, Zhen Tan, MM a, Tianqiang Qin, MM c, Pengde Kang, MD a a b c
Department of Orthopedics, West China Hospital, Sichuan University, Chengdu, China Department of Rehabilitation Medicine, West China Hospital, Sichuan University, Chengdu, China Chinese Evidence-Based Medicine Centre/Cochrane Center, West China Hospital, Chengdu, China
a r t i c l e
i n f o
Article history: Received 5 November 2014 Accepted 23 February 2015 Available online xxxx Keywords: total hip arthroplasty femoral neck fracture internal fixation perioperative period complication
a b s t r a c t The outcome of total hip arthroplasty (THA) for failed internal fixation after femoral neck fracture (FNF) versus that for acute displaced femoral neck fracture is still controversial. This study retrospectively analyzed a consecutive series of 130 THAs for acute displaced FNF (64, group I) and for failed internal fixation (66, group II). Results showed THAs in group II were more technically demanding procedures with longer operative time and larger amounts of drainage compared to that in group I. Furthermore, multivariate analysis revealed that the associations between THAs (group II) and hip complications were notable (OR = 4.15, P = 0.017). These increased risks should be paid much attention to, not only for choosing the appropriate treatment option, but also for providing effective perioperative care. © 2015 Elsevier Inc. All rights reserved.
With population growth and aging, femoral neck fracture (FNF), accounting for nearly half of all hip fractures with the majority occurring in elderly patients after simple falls [1], continues to increase in numbers and significance [2–4]. The annual estimated worldwide direct and indirect costs of hip fractures are expected to rise to $131 billion by 2050 from the estimated $34.8 billion in 1990 [2]. Among the main three surgical strategies including internal fixation (IF), hemiarthroplasty (HA) and total hip arthroplasty (THA) for FNF, THA could be effective in pain relief and provide superior and more durable function in a subset of patients with displaced FNF when compared to HA or uncomplicated osteosynthesis [5]. Accumulating of high quality evidence demonstrates that THA has a larger role in the treatment of displaced FNF than it has in the past, resulting in less short-term complications and/or better longterm implant survival [6–14]. Furthermore, currently available data [15–17] support the use of THA as a more cost-effective treatment strategy in this specific population, despite relatively higher costs at the initial admission or early follow-up compared to IF or HA. The increased upfront cost appears to be offset by the improved functional results. However, in spite of high failure rate for IF, the method is still recommended for this specific cohort by some authors. It is claimed that preserving the natural femoral head will obtain better hip function than replacing it with an artificial one. It is also argued that, even if the IF failed, salvage THA could also yield good results comparable to primary THA No author associated with this paper has disclosed any potential or pertinent conflicts which may be perceived to have impending conflict with this work. For full disclosure statements refer to http://dx.doi.org/10.1016/j.arth.2015.02.037. Reprint requests: Pengde Kang, Ph.D., M.D., Department of Orthopedics, West China Hospital, Sichuan University, Chengdu, Sichuan, China, 610041.
[18–20]. On the contrary, previous studies have also found THA following failed IF after FNF led to increased risk of early complication, inferior hip function and higher revision rate [21–23]. Whether salvage THA for failed IF—as compared to primary THA obtains similar results is a matter of vigorous debate. Moreover, we are unaware of any studies focusing on comparison of perioperative outcomes including operative difficulties and complications between primary and salvage THA for FNF. The main purpose of our study therefore, is to assess the immediate results of salvage THAs following failed IF after FNF, compared with primary THAs for elderly patients with displaced FNF by retrospectively analyzing the prospectively collected data of joint arthroplasty cohort from our institution. We hypothesized that salvage THA for failed IF would be a more technically demanding procedure with prolonged operative times, larger amounts of intra-operative blood loss and post-operative drainage and higher proportion of transfusion, and also be at increased risk of developing complications during perioperative period compared to primary THA for acute displaced FNF. Patients and Methods Study Design and Subjects With the approval of ethics committee of our institution, we conducted a retrospective cohort study employing joint arthroplasty data from the 2009 to 2014. These data were prospectively collected in a special database, Administrative System of Orthopedic Medical Records (Joint Arthroplasty), which was created and maintained by a team of assigned staff members since 2009. Patients once admitted to our
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Please cite this article as: Yang Z, et al, Total Hip Arthroplasty for Failed Internal Fixation After Femoral Neck Fracture Versus That for Acute Displaced Femoral Neck Fracture: A Comparative Study, J Arthroplasty (2015), http://dx.doi.org/10.1016/j.arth.2015.02.037
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Z. Yang et al. / The Journal of Arthroplasty xxx (2015) xxx–xxx
Department of Joint Surgery were all registered into this database. The register contains patient demographics, surgery-related information, prosthesis information and records of clinical and radiographic assessment during perioperative period. In present study, potentially eligible patients who underwent primary THA for FNF were indentified with algorithms using procedure and diagnosis codes (ICD-10) in the database from 2009 to 2014. Patients aged 60 or over were included for further selection. Of the consecutive series of 174 initially screened THAs, there were 70 THAs due to FNF, 68 THAs due to failed internal fixation (group II), 33 patients due to sequelae of FNF with conservative treatment and another three patients with unavailable data. Acute FNF was defined as a fracture treated within 3 weeks of occurrence. Only patients with acute displaced FNF (Garden III, Garden IV) [24] were included into the primary group (group I). Patients diagnosed with sequelae after FNF, without an earlier operation for the fracture were excluded. Patients were also excluded for infection after internal fixation or incomplete data. Finally, a total of 64 patients were included in group I meanwhile 66 in group II. Unilateral THA was performed for each patient. Two in group II developed deep infection after IF following FNF and these patients underwent a two-stage THA (the first operation was performed for hardware removal, thorough debridement and implantation of temporary prosthesis composed of acrylic cement impregnated with antibiotic, and the second was performed for prosthesis implantation after some time of infection healing) and thus were not included into group II. Operative Details Five senior surgeons who had carried out more than 200 joint arthroplasties annually performed the THAs in a modern operating room with ultra-clean air filtration and vertical laminar air flow. The patients were in the lateral decubitus position, under general anesthesia (almost all, 125/130). Operations were carried out using a posterolateral surgical approach with implants produced by Depuy or Stryker Orthopedics Company. The choice of using either a cemented or an uncemented component depended upon the quality of bone stock and femoral canal anatomy. All patients received perioperative antibiotics, standard postoperative anticoagulation, closed suction wound drainage (removed on the first postoperative day), ice bags upon wounds (intermittently within 24 hours after operation) and pneumatic compression with foot pumps. The standard rehabilitation program consisting of weight bearing as tolerated with walking aid started the day after surgery for 2 weeks. Information of Interest Information on patient age at the index surgery, gender, weight, height, preoperative comorbid conditions (defined by the Deyo index [25], adapted Charlson comorbidity index [26]), reasons for IF failure, type of internal fixation, prosthesis type, prosthesis fixation method, and femoral head size was extracted from records in the database. The primary outcomes of interest contain length of stay (LOS, including preoperative LOS, postoperative LOS), operative time, blood loss, transfusion volume, perioperative complications including general medical complications (postoperative nausea and vomiting (PONV), gastroenteric stress ulcer, deep venous thrombosis (DVT), pulmonary embolism (PE), acute coronary syndrome (ACS), respiratory tract infections, pneumonia, urinary retention, urinary tract infection, acute renal failure, paralytic ileus) and hip complications (hematoma, fat liquefaction of incision, peripheral nerve injury, infection (wound infection and periprosthetic infection), dislocation, periprosthetic fracture). Statistical Analysis Statistical analysis was performed by two investigators using SPSS (version 16.0, Chicago, Illinois, USA). Continuous variables were described with mean and standard deviation, or median and range while categorical variables with frequencies and percentage. Normal
distribution and homogeneity of variance was examined using the Kolmogorov–Smirnov test and the Levene's test respectively for quantitative variables. Categorical variables were compared between the two groups by using chi-square test (or Fisher exact tests where appropriate) while continuous variables were compared by using t tests for two independent samples or analysis of variance (ANOVA) for multiple groups. Multiple comparisons were conducted following ANOVA by using the LSD’s (least significant difference) post hoc tests. Significant difference was considered present with a two-side P value less than 0.05. Univariate and multivariate logistic regression analysis was used to determine the effect of patient-based factors such as age, gender, BMI, comorbidity, surgery type (salvage VS primary) on the development of overall perioperative complications as well as general medical complications or hip complications. Patients’ age was categorized as sixty to sixtynine years of age, seventy to seventy-nine years of age, or eighty years of age and older. Since all patients were Chinese, body weight index (BMI) was categorized as b24 and ≥24 kg/m2 based on epidemiological survey of Chinese BMI [27]. The threshold value distinguishing different body weight statuses in China is distinct with Western Europe and North America. Patients’ Deyo index (modified Charlson comorbidity index scores) ranged from 0 to 4, but this was dichotomized into presence or absence of comorbidities due to skewed frequency distribution with a low median and few high scores. The five independent variables aforementioned were all entered into the final multivariate model. Both perioperative antibiotic prophylaxis and surgical approach were not included in the model as all patients in this consecutive series received prophylactic antibiotics and moreover, were operated using the same traditional surgical approach, posterolateral approach. The Hosmer–Lemeshow goodness-of-fit test was used to assess the fitness of the logistic regression model. Significant independent predictors were determined to be those that maintained P value of b0.05 with the odds ratio (OR) or 95% confidence interval (CI) exclusive of 1.0.
Result Of the total 130 THAs, 128 patients were implanted with a cementless THA, one with a cemented THA, and one with a hybrid THA. Ten cups were additionally fixated with screws. There were 38 (59.4%) of 64 primary THA patients implanted with ceramic-on-ceramic (C/C) bearings, 15 (23.4%) of 64 with ceramic-onpolyethylene (C/P) bearings, 6 (9.4%) of 64 with metal-on-metal (M/M) bearings, 2 (3.1%) of 66 with metal-on-polyethylene (M/P) bearings, and 3 (4.7%) of 66 with ceramic-on-metal (C/M) bearings. Comparatively, 40 (60.6%) of 66 salvage THA patients were implanted with C/C bearings, 18 (27.3%) of 66 with C/P bearings, 4 (6.1%) of 66 with M/M bearings, 1 (1.5%) of 66 with M/P bearings, and 3 (4.5%) of 66 with C/M bearings. The THAs in group I were performed with a head size of 28 mm (n = 8), 32 mm (n = 25), and 36 mm or greater (n = 33) respectively, while those in group II were 28 mm (n = 10), 32 mm (n = 31), and 36 mm or greater (n = 23). The differences of fixation methods, bearings types and head size between group I and group II were all not statistically significant. Of the 64 THAs in group I, 61 were performed due to simple falls and the other three were due to high energy trauma. In group II, 49 patients were initially treated with 2 or 3 cannulated screws, 6 with dynamic hip screws, 3 with Kirschner wires and the remaining were treated with other internal fixation (unknown in details) and there were 34 of the patients with retained hardware at the index surgery. The reasons necessitating patients to undergo THA in group II were as follows: 50 cases suffered from osteonecrosis of femoral head, 9 cases suffered from nonunion, 4 cases suffered from posttraumatic arthritis, and 3 cases suffered from aseptic loosening of fixation devices. The time from first symptoms after IF to salvage THA was 2 years (median) and ranged from 1 month to 30 years.
Please cite this article as: Yang Z, et al, Total Hip Arthroplasty for Failed Internal Fixation After Femoral Neck Fracture Versus That for Acute Displaced Femoral Neck Fracture: A Comparative Study, J Arthroplasty (2015), http://dx.doi.org/10.1016/j.arth.2015.02.037
Z. Yang et al. / The Journal of Arthroplasty xxx (2015) xxx–xxx
In the comparison of patient demographics and pre-operative characteristics between groups, no significant differences were found (as shown in Table A.1). Table B.1 showed that there were no statistically significant differences in the overall LOS, pre-operative and post-operative LOS between the two groups. The mean operative time (skin- to -skin) was 88.42 ± 34.09 minutes (min). Given retained hardware was removed from half of the patients in the group II, comparisons were made additionally between patients with or without hardware in the group. The result of ANOVA showed significant difference in the three groups (P b 0.001, not provided in Table B.2) and then LSD’s post hoc tests were conducted to further multiple comparisons, and found the average operative time in group I was shorter than that in both subgroups of group II (P = 0.019, P b 0.001, Table B.2), but there was no significant difference observed between these two subgroups (P N 0.05, Table B.2). A larger amounts of intra-operative blood loss and drainage within 24 hours after operation were collected in group II compared with that in group I, but only drainage volume demonstrated significant difference between groups (P b 0.001).There were no significant differences in the proportion of transfusion of red blood cell, plasma or salvaged autologous blood between the two groups (P N 0.05). Likewise, there were no significant differences in the corresponding volume of transfusions between the two groups (P N 0.05). As for complications, patients in group II were more likely to develop hip complications (P = 0.031, Table B.1). No significant differences were noted in the occurrence rate of individual complication, overall complications and general medical complications between groups. Pulmonary embolism (PE), acute coronary syndrome, acute renal failure, gastroenteric stress ulcer, paralytic ileus and peripheral nerve injury were not observed in both groups. Univariate logistic regression analysis primarily identified risk factors for overall complications, general medical complications and hip complications. Only notable among these was the association of salvage THA with hip complications (OR = 3.18, 95%CI, 1.07–9.42, Table C.1). Multivariate logistic regression model determined the patient-based risk factors for the three outcome variables mentioned above and results were similar to univariate analysis. Patients in group II had increased risk of developing hip complications (OR = 4.15, 95%CI, 1.29–13.34, Table C.1).The Hosmer–Lemeshow goodness-of-fit test showed no evidence of a lack of fit for any characteristic analyzed in this study. Discussion Prior studies [21–23,28–30] mostly concerned outcomes of salvage THAs for failed IF such as prosthesis survival and function assessment compared with either elective osteoarthritic THAs or THAs due to proximal femur fracture. Our present study was to assess the immediate results of salvage THAs for patients with failed IF after FNF compared with those for acute displaced FNF and to determine whether salvage THA is an independent risk factor of perioperative complications. Although we hypothesized that individuals in group II would have poorer surgical outcomes than those in group I, we only observed prolonged operative time, larger amounts of drainage and increased risk of developing hip complications. Surgical efficiency, represented by decreased operative time, was reflected in group I (76.72 ± 24.85 min) compared with that in group II (99.77 ± 37.97 min) (not shown in tables). This is consistent with the findings of prior study [31] in which patients with failed IF had prolonged operative time (114.82 ± 32.13 min) in comparison with that in FNF group (90.63 ± 16.24 min) (P b 0.05). Since half of the patients in the salvage group underwent extraction of internal fixation devices, group II was divided into two subgroups and then compared with group I. As expected, similar result was found that the average operative time in group I was shorter than that in both subgroups of group II (P = 0.019, P b 0.001, Table C.1), but no significant difference between the two subgroups (P N 0.05, Table C.1). However, in Wang et al’s study [31], patients without hardware before THAs were not described, subgroup analysis was not mentioned either. The average operative time
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in group I (76.72 ± 24.85 min) was comparable to that (72.9 ± 9.5 min) in previous study conducted by Zeng et al [32]. But the patients included in the study were younger than age of sixty, accompanied with male to female proportion about one to one. As for longer operative time for patients with failed IF, potentially reasonable explanations could be those reviewed by Angelini et al [33] in 2009 and Petrie et al [34] in 2013 that disuse osteopenia, deformity, residual bony defect with removal of the original hardware in the proximal femur all pose technical challenges to successful reconstruction. Furthermore, because of absence of sclerotic subchondral bone typically present in elective osteoarthritic THAs instead of these salvage THAs, the insertion of cementless acetabular components may be difficult due to poor press-fit fixation. Accordingly acetabular reaming should be done carefully, making efforts to preserve the subchondral bone as possible and avoid forceful acetabular component impaction; and additional component fixation with screws might be performed when necessary. It has been reported that longer time for THA was associated with the elevation in relative risk of venous thromboembolism and greater probability of complications [35,36]. This information will be of value when advising patients about the risks of THA and managing them postoperatively. Unlike with our assumption, the mean intra-operative blood loss in group II was just slightly more than that in group I and no significant difference was observed between the two groups. This is inconsistent with findings of Wang et al’s study [31] in which there exists significant difference. As to drainage, patients with failed IF were more likely to get larger amounts compared to those with FNF. Plausible reasons for this could be scar healing and deformity with previous surgery, probably resulting in more surgical injuries [33]. The mean length of hospital stay (about twelve days) was relatively longer and not statistically different between the two groups in the current study. Other investigations [37–39] demonstrated that the length of stay ranged from about 4 to 9 days. This may be due to patient differences, medical resources, and discharge planning protocol of the hospital. In the current study, we comprehensively assessed complications to quantify the relative risk associated with salvage THA (VS primary THA) for patients with FNF using multivariate logistic regression analysis. Our findings suggest that patients with failed IF were at elevated risk of developing hip complications. This is consistent with previous findings [23] that patients with salvage THA were at increased risk of complications despite different durations of follow up. POVN is a common and critical problem that requests additional attention during perioperative period. Severe POVN may lead to adverse effects such as aspiration pneumonia, cardiovascular events or prolonged length of hospital stay and so on [40]. Therefore, it was extremely essential to include this into general medical complications. Increased operative time is one of the surgery related factors influencing POVN [40]. Presumably its occurrence rate could reflect the operative time to some degree in the present study. But no significant difference was found between the two groups. This may be influenced by other factors such as anesthetic types [40]. As for postoperative hematoma and fat liquefaction of incision, both are associated with increased risk of wound infection and included into hip complications [41]. Similarly, both occurred slightly often in group II although there was no statistical significance. It has been revealed by studies [23,42] that salvage THA for FNF had higher occurrence rate of dislocation, periprosthetic fracture, and superficial infections. In the current study, there was only one periprosthetic infection, one dislocation due to simple fall, one periprosthetic fracture with severe osteoporosis (with the corresponding P N 0.05). In a prospective cohort study of dislocation of THA in patients with FNF, Enocson et al [43] reported that posterolateral approach was associated with a significantly increased risk of dislocation. Although all of the THAs were performed through posterolateral approach in our study, the incidence rate of dislocation was low (1/130, 0.8%). The dislocation in THAs could also decrease with larger size of prosthetic femoral head [44,45]. About 86.2% patients in the present cohort adopted artificial
Please cite this article as: Yang Z, et al, Total Hip Arthroplasty for Failed Internal Fixation After Femoral Neck Fracture Versus That for Acute Displaced Femoral Neck Fracture: A Comparative Study, J Arthroplasty (2015), http://dx.doi.org/10.1016/j.arth.2015.02.037
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femoral heads with the diameter of 32 mm or greater. In addition, the lower incidence of dislocation in present study may be also partly due to shorter durations of follow up for this specific endpoint. There are several limitations to our present study. First, with a relatively small sample size, our study is underpowered to determine true differences of individual complication between the two groups, however, it still represents one of the larger series reported so far in the literature. Second, American Society of Anesthesiologists (ASA) score as a measure of general health status, related to immediate postoperative complication, was not included in the multivariate analysis. Third, combination of clinical result and function evaluation could comprehensively evaluate the treatment outcome of salvage THA. However, in current study, postoperative function was not assessed for this cohort of patients since it was not recorded in our database, which makes our present study imperfect. In conclusion, present study suggested that salvage THA for failed IF following FNF was a more technically demanding procedure with prolonged operative time and larger amounts of postoperative drainage (within 24 hours), and was at increased risk of developing hip complications compared to primary THA for acute displaced FNF. These increased risks should be paid much attention to, not only for choosing the appropriate treatment option, but also for providing effective perioperative care. Appendix A
Table A.1 Patient Demographics and Preoperative Characteristics.
No. Age ≥60, b70 ≥70, b80 ≥80 Gender Male Female Weight Height BMI in kg/m2 b18.5 ≥18.5, ≤23.9 ≥24.0, ≤27.9 ≥28 Deyo index 0 1 2 3 or more
Group I
Group II
64 71.3 ± 6.1 27 (42.2%) 32 (50.0%) 5 (7.8%)
66 69.6 ± 6.5 35 (53.0%) 26 (39.4%) 5 (7.6%)
13 (20.3%) 51 (79.7%) 56.8 ± 11.4 Kg 159 ± 7.2 cm 22.0 ± 4.7 5 (7.8%) 41 (64.1%) 15 (23.4%) 3 (4.7%)
24 (36.4%) 42 (63.6%) 59.9 ± 10.6 Kg 161 ± 7.3 cm 22.9 ± 2.8 6 (9.1%) 39 (59.1%) 18 (27.3%) 3 (4.5%)
39 (60.9%) 19 (29.7%) 3 (4.7%) 3 (4.7%)
48 (72.7%) 13 (19.7%) 5 (7.6%) 0 (0.0%)
P Value N0.05
N0.05
N0.05 N0.05 N0.05
N0.05
Data are displayed using means ± SD or n (%); group I represents primary THAs for acute displaced femoral neck fracture while group II represents salvage THAs for failed internal fixation after femoral neck fracture. Table B.1 Comparison of Outcomes During Perioperative Period Between Groups. Outcomes
Group I
Group II
P Value
Length of stay Pre-LOS Post-LOS Blood loss (intra-) Transfusion proportion Red blood cell Transfusion proportion Plasma Transfusion proportion Autologous blood 24 h drain Overall complications General medical complications PONV DVT Urinary retention Urinary tract infection Pneumonia Respiratory tract infection Hip complications Fat liquefaction of incision Hematoma Dislocation Infection Periprosthetic fracture
12.89 ± 5.51 d 5.91 ± 4.43 d 6.98 ± 2.71 d 232.34 ± 125.80 ml 30/64 (46.9%) 406.67 ± 493.18 ml 15/64 (23.4%) 463.33 ± 315.93 ml 11/64 (17.2%) 114.09 ± 99.07 ml 231.80 ± 159.01 ml 18 (28.13%) 15 (23.44%) 3 (4.69%) 3 (4.69%) 1 (1.56%) 2 (3.13%) 3 (4.69%) 4 (6.25%) 5 (7.81%) 1 (1.56%) 3 (4.69%) 1(1.56%) 0 (0.0%) 0 (0.0%)
12.06 ± 5.40 d 5.33 ± 3.15 d 6.73 ± 3.20 d 253.64 ± 171.95 ml 28/66 (42.4%) 428.57 ± 352.09 ml 14/66 (21.2%) 467.86 ± 331.44 ml 10/66 (15.2%) 145.00 ± 72.46 ml 392.27 ± 241.49 ml 25 (37.88%) 13 (19.70%) 7 (10.61%) 2 (3.03%) 2 (3.03%) 0 (0.0%) 0 (0.0%) 3 (4.55%) 14 (21.21%) 5 (7.50%) 7 (10.61%) 0 (0.0%) 1 (1.52%) 1 (1.52%)
N0.05 N0.05 N0.05 N0.05 N0.05 N0.05 N0.05 N0.05 N0.05 N0.05 b0.001⁎ N0.05 N0.05 N0.05 N0.05 N0.05 N0.05 N0.05 N0.05 0.031* N0.05 N0.05 N0.05 N0.05 N0.05
Data are displayed using means ± SD or n (%); LOS is short for length of stay; group I represents primary THAs for acute displaced femoral neck fracture while group II represents salvage THAs for failed internal fixation after femoral neck fracture; * means the difference is significant at the 0.05 level. Individual complication was calculated according to number of cases while summary complications were calculated according to number of patients.
Please cite this article as: Yang Z, et al, Total Hip Arthroplasty for Failed Internal Fixation After Femoral Neck Fracture Versus That for Acute Displaced Femoral Neck Fracture: A Comparative Study, J Arthroplasty (2015), http://dx.doi.org/10.1016/j.arth.2015.02.037
Z. Yang et al. / The Journal of Arthroplasty xxx (2015) xxx–xxx
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Table B.2 Multiple Comparison of Operative Time Using LSD’s Post Hoc Test. Mean(I, 95%CI)(minute)
Group(J)
Mean Difference(I-J,95%CI)
P Value
a
Group(I)
34
106.03 (94.86–117.19)
b
32
93.12 (77.64–108.61)
c
64
76.72 (70.51–82.93)
b c a c a b
12.91 (−2.68 to 28.49) 29.31⁎ (15.87 to 42.75) −12.91 (−28.49 to 2.68) 16.40⁎ (2.71 to 30.11) −29.31⁎ (−42.75 to −15.87) −16.40⁎ (−30.11 to −2.71)
PN Pb PN P= Pb P=
130
88.42 (82.51–94.34)
Total
No.(I)
0.05 0.001 0.05 0.019 0.001 0.019
Group “a” represents patients in salvage group with hardware retained in the lesion; “b” represents those without hardware, “c” for patients with primary THA in group I; each asterisk means the difference is significant.
Table C.1 Univariate and Multivariate Analysis for Risk Factors of complications. Univariate Analysis Outcome/Risk Factor General medical complication Salvage VS primary THA Age 60–70 Age 70–80 Age 80 or older Male VS female Body mass index in kg/m2 BMI ≥24 VS BMI b24 Comorbidity Presence VS absence Hip complication Salvage VS primary THA Age 60–70 Age 70–80 Age 80 or older Male VS female Body mass index in kg/m2 BMI ≥24 VS BMI b24 Comorbidity Presence VS absence Overall complication Salvage VS primary THA Age 60–70 Age 70–80 Age 80 or older Male VS female Body mass index in kg/m2 BMI ≥24 VS BMI b24 Comorbidity Presence VS absence
Multivariate Analysis
OR
95%CI
Adjusted OR
95%CI
0.80
0.35–1.85
0.77
0.32–1.86
0.98 1.62 0.80
0.41–2.38 0.37–7.13 0.31–2.08
0.85 1.68 0.96
0.34–2.11 0.36–7.85 0.35–2.65
0.44
0.15–1.24
0.44
0.15–1.30
0.77
0.31–1.91
0.74
0.28–1.97
3.18
1.07–9.42
4.15
1.29–13.34⁎
0.81 2.52 0.63
0.28–2.33 0.55–11.61 0.20–2.04
0.96 2.68 0.39
0.32–2.89 0.52–13.70 0.11–1.41
1.01
0.38–3.12
1.09
0.35–3.36
1.58
0.58–4.27
2.13
0.70–6.51
1.56
0.75–3.26
1.86
0.84–4.12
1.19 3.67 0.67
0.55–2.59 0.92–14.56 0.30–1.56
1.21 3.94 0.58
0.54–2.69 0.93–16.79 0.23–1.44
0.61
0.26–1.40
0.63
0.26–1.53
1.13
0.52–2.44
1.25
0.54–2.89
OR N1 indicates salvage total hip arthroplasties (THAs) are at increased risk of the complications compared with primary THAs for femoral neck fracture, whereas OR b1 indicates salvage THAs are at decreased risk of the complications. The corresponding 95% confidence intervals (CI) reveal that the result is statistically significant when ‘1’ is not included in the interval, whereas when ‘1’ is included in the interval, the result is not statistically significant.
Acknowledgements All authors agree to list H. Liu as a co-first author, who made major contributions to the writing of the revised manuscript.
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Please cite this article as: Yang Z, et al, Total Hip Arthroplasty for Failed Internal Fixation After Femoral Neck Fracture Versus That for Acute Displaced Femoral Neck Fracture: A Comparative Study, J Arthroplasty (2015), http://dx.doi.org/10.1016/j.arth.2015.02.037
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Total Hip Arthroplasty for Failed Internal Fixation After Femoral Neck Fracture Versus That for Acute Displaced Femoral Neck Fracture: A Comparative Study Zhouyuan Yang, MM a, Huifang Liu, MD b, Xiaowei Xie, MD a, Zhen Tan, MM a, Tianqiang Qin, MM c, Pengde Kang, MD a a b c
Department of Orthopedics, West China Hospital, Sichuan University, Chengdu, China Department of Rehabilitation Medicine, West China Hospital, Sichuan University, Chengdu, China Chinese Evidence-Based Medicine Centre/Cochrane Center, West China Hospital, Chengdu, China
a r t i c l e
i n f o
Article history: Received 5 November 2014 Accepted 23 February 2015 Available online xxxx Keywords: total hip arthroplasty femoral neck fracture internal fixation perioperative period complication
a b s t r a c t The outcome of total hip arthroplasty (THA) for failed internal fixation after femoral neck fracture (FNF) versus that for acute displaced femoral neck fracture is still controversial. This study retrospectively analyzed a consecutive series of 130 THAs for acute displaced FNF (64, group I) and for failed internal fixation (66, group II). Results showed THAs in group II were more technically demanding procedures with longer operative time and larger amounts of drainage compared to that in group I. Furthermore, multivariate analysis revealed that the associations between THAs (group II) and hip complications were notable (OR = 4.15, P = 0.017). These increased risks should be paid much attention to, not only for choosing the appropriate treatment option, but also for providing effective perioperative care. © 2015 Elsevier Inc. All rights reserved.
With population growth and aging, femoral neck fracture (FNF), accounting for nearly half of all hip fractures with the majority occurring in elderly patients after simple falls [1], continues to increase in numbers and significance [2–4]. The annual estimated worldwide direct and indirect costs of hip fractures are expected to rise to $131 billion by 2050 from the estimated $34.8 billion in 1990 [2]. Among the main three surgical strategies including internal fixation (IF), hemiarthroplasty (HA) and total hip arthroplasty (THA) for FNF, THA could be effective in pain relief and provide superior and more durable function in a subset of patients with displaced FNF when compared to HA or uncomplicated osteosynthesis [5]. Accumulating of high quality evidence demonstrates that THA has a larger role in the treatment of displaced FNF than it has in the past, resulting in less short-term complications and/or better longterm implant survival [6–14]. Furthermore, currently available data [15–17] support the use of THA as a more cost-effective treatment strategy in this specific population, despite relatively higher costs at the initial admission or early follow-up compared to IF or HA. The increased upfront cost appears to be offset by the improved functional results. However, in spite of high failure rate for IF, the method is still recommended for this specific cohort by some authors. It is claimed that preserving the natural femoral head will obtain better hip function than replacing it with an artificial one. It is also argued that, even if the IF failed, salvage THA could also yield good results comparable to primary THA No author associated with this paper has disclosed any potential or pertinent conflicts which may be perceived to have impending conflict with this work. For full disclosure statements refer to http://dx.doi.org/10.1016/j.arth.2015.02.037. Reprint requests: Pengde Kang, Ph.D., M.D., Department of Orthopedics, West China Hospital, Sichuan University, Chengdu, Sichuan, China, 610041.
[18–20]. On the contrary, previous studies have also found THA following failed IF after FNF led to increased risk of early complication, inferior hip function and higher revision rate [21–23]. Whether salvage THA for failed IF—as compared to primary THA obtains similar results is a matter of vigorous debate. Moreover, we are unaware of any studies focusing on comparison of perioperative outcomes including operative difficulties and complications between primary and salvage THA for FNF. The main purpose of our study therefore, is to assess the immediate results of salvage THAs following failed IF after FNF, compared with primary THAs for elderly patients with displaced FNF by retrospectively analyzing the prospectively collected data of joint arthroplasty cohort from our institution. We hypothesized that salvage THA for failed IF would be a more technically demanding procedure with prolonged operative times, larger amounts of intra-operative blood loss and post-operative drainage and higher proportion of transfusion, and also be at increased risk of developing complications during perioperative period compared to primary THA for acute displaced FNF. Patients and Methods Study Design and Subjects With the approval of ethics committee of our institution, we conducted a retrospective cohort study employing joint arthroplasty data from the 2009 to 2014. These data were prospectively collected in a special database, Administrative System of Orthopedic Medical Records (Joint Arthroplasty), which was created and maintained by a team of assigned staff members since 2009. Patients once admitted to our
http://dx.doi.org/10.1016/j.arth.2015.02.037 0883-5403/© 2015 Elsevier Inc. All rights reserved.
Please cite this article as: Yang Z, et al, Total Hip Arthroplasty for Failed Internal Fixation After Femoral Neck Fracture Versus That for Acute Displaced Femoral Neck Fracture: A Comparative Study, J Arthroplasty (2015), http://dx.doi.org/10.1016/j.arth.2015.02.037
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Department of Joint Surgery were all registered into this database. The register contains patient demographics, surgery-related information, prosthesis information and records of clinical and radiographic assessment during perioperative period. In present study, potentially eligible patients who underwent primary THA for FNF were indentified with algorithms using procedure and diagnosis codes (ICD-10) in the database from 2009 to 2014. Patients aged 60 or over were included for further selection. Of the consecutive series of 174 initially screened THAs, there were 70 THAs due to FNF, 68 THAs due to failed internal fixation (group II), 33 patients due to sequelae of FNF with conservative treatment and another three patients with unavailable data. Acute FNF was defined as a fracture treated within 3 weeks of occurrence. Only patients with acute displaced FNF (Garden III, Garden IV) [24] were included into the primary group (group I). Patients diagnosed with sequelae after FNF, without an earlier operation for the fracture were excluded. Patients were also excluded for infection after internal fixation or incomplete data. Finally, a total of 64 patients were included in group I meanwhile 66 in group II. Unilateral THA was performed for each patient. Two in group II developed deep infection after IF following FNF and these patients underwent a two-stage THA (the first operation was performed for hardware removal, thorough debridement and implantation of temporary prosthesis composed of acrylic cement impregnated with antibiotic, and the second was performed for prosthesis implantation after some time of infection healing) and thus were not included into group II. Operative Details Five senior surgeons who had carried out more than 200 joint arthroplasties annually performed the THAs in a modern operating room with ultra-clean air filtration and vertical laminar air flow. The patients were in the lateral decubitus position, under general anesthesia (almost all, 125/130). Operations were carried out using a posterolateral surgical approach with implants produced by Depuy or Stryker Orthopedics Company. The choice of using either a cemented or an uncemented component depended upon the quality of bone stock and femoral canal anatomy. All patients received perioperative antibiotics, standard postoperative anticoagulation, closed suction wound drainage (removed on the first postoperative day), ice bags upon wounds (intermittently within 24 hours after operation) and pneumatic compression with foot pumps. The standard rehabilitation program consisting of weight bearing as tolerated with walking aid started the day after surgery for 2 weeks. Information of Interest Information on patient age at the index surgery, gender, weight, height, preoperative comorbid conditions (defined by the Deyo index [25], adapted Charlson comorbidity index [26]), reasons for IF failure, type of internal fixation, prosthesis type, prosthesis fixation method, and femoral head size was extracted from records in the database. The primary outcomes of interest contain length of stay (LOS, including preoperative LOS, postoperative LOS), operative time, blood loss, transfusion volume, perioperative complications including general medical complications (postoperative nausea and vomiting (PONV), gastroenteric stress ulcer, deep venous thrombosis (DVT), pulmonary embolism (PE), acute coronary syndrome (ACS), respiratory tract infections, pneumonia, urinary retention, urinary tract infection, acute renal failure, paralytic ileus) and hip complications (hematoma, fat liquefaction of incision, peripheral nerve injury, infection (wound infection and periprosthetic infection), dislocation, periprosthetic fracture). Statistical Analysis Statistical analysis was performed by two investigators using SPSS (version 16.0, Chicago, Illinois, USA). Continuous variables were described with mean and standard deviation, or median and range while categorical variables with frequencies and percentage. Normal
distribution and homogeneity of variance was examined using the Kolmogorov–Smirnov test and the Levene's test respectively for quantitative variables. Categorical variables were compared between the two groups by using chi-square test (or Fisher exact tests where appropriate) while continuous variables were compared by using t tests for two independent samples or analysis of variance (ANOVA) for multiple groups. Multiple comparisons were conducted following ANOVA by using the LSD’s (least significant difference) post hoc tests. Significant difference was considered present with a two-side P value less than 0.05. Univariate and multivariate logistic regression analysis was used to determine the effect of patient-based factors such as age, gender, BMI, comorbidity, surgery type (salvage VS primary) on the development of overall perioperative complications as well as general medical complications or hip complications. Patients’ age was categorized as sixty to sixtynine years of age, seventy to seventy-nine years of age, or eighty years of age and older. Since all patients were Chinese, body weight index (BMI) was categorized as b24 and ≥24 kg/m2 based on epidemiological survey of Chinese BMI [27]. The threshold value distinguishing different body weight statuses in China is distinct with Western Europe and North America. Patients’ Deyo index (modified Charlson comorbidity index scores) ranged from 0 to 4, but this was dichotomized into presence or absence of comorbidities due to skewed frequency distribution with a low median and few high scores. The five independent variables aforementioned were all entered into the final multivariate model. Both perioperative antibiotic prophylaxis and surgical approach were not included in the model as all patients in this consecutive series received prophylactic antibiotics and moreover, were operated using the same traditional surgical approach, posterolateral approach. The Hosmer–Lemeshow goodness-of-fit test was used to assess the fitness of the logistic regression model. Significant independent predictors were determined to be those that maintained P value of b0.05 with the odds ratio (OR) or 95% confidence interval (CI) exclusive of 1.0.
Result Of the total 130 THAs, 128 patients were implanted with a cementless THA, one with a cemented THA, and one with a hybrid THA. Ten cups were additionally fixated with screws. There were 38 (59.4%) of 64 primary THA patients implanted with ceramic-on-ceramic (C/C) bearings, 15 (23.4%) of 64 with ceramic-onpolyethylene (C/P) bearings, 6 (9.4%) of 64 with metal-on-metal (M/M) bearings, 2 (3.1%) of 66 with metal-on-polyethylene (M/P) bearings, and 3 (4.7%) of 66 with ceramic-on-metal (C/M) bearings. Comparatively, 40 (60.6%) of 66 salvage THA patients were implanted with C/C bearings, 18 (27.3%) of 66 with C/P bearings, 4 (6.1%) of 66 with M/M bearings, 1 (1.5%) of 66 with M/P bearings, and 3 (4.5%) of 66 with C/M bearings. The THAs in group I were performed with a head size of 28 mm (n = 8), 32 mm (n = 25), and 36 mm or greater (n = 33) respectively, while those in group II were 28 mm (n = 10), 32 mm (n = 31), and 36 mm or greater (n = 23). The differences of fixation methods, bearings types and head size between group I and group II were all not statistically significant. Of the 64 THAs in group I, 61 were performed due to simple falls and the other three were due to high energy trauma. In group II, 49 patients were initially treated with 2 or 3 cannulated screws, 6 with dynamic hip screws, 3 with Kirschner wires and the remaining were treated with other internal fixation (unknown in details) and there were 34 of the patients with retained hardware at the index surgery. The reasons necessitating patients to undergo THA in group II were as follows: 50 cases suffered from osteonecrosis of femoral head, 9 cases suffered from nonunion, 4 cases suffered from posttraumatic arthritis, and 3 cases suffered from aseptic loosening of fixation devices. The time from first symptoms after IF to salvage THA was 2 years (median) and ranged from 1 month to 30 years.
Please cite this article as: Yang Z, et al, Total Hip Arthroplasty for Failed Internal Fixation After Femoral Neck Fracture Versus That for Acute Displaced Femoral Neck Fracture: A Comparative Study, J Arthroplasty (2015), http://dx.doi.org/10.1016/j.arth.2015.02.037
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In the comparison of patient demographics and pre-operative characteristics between groups, no significant differences were found (as shown in Table A.1). Table B.1 showed that there were no statistically significant differences in the overall LOS, pre-operative and post-operative LOS between the two groups. The mean operative time (skin- to -skin) was 88.42 ± 34.09 minutes (min). Given retained hardware was removed from half of the patients in the group II, comparisons were made additionally between patients with or without hardware in the group. The result of ANOVA showed significant difference in the three groups (P b 0.001, not provided in Table B.2) and then LSD’s post hoc tests were conducted to further multiple comparisons, and found the average operative time in group I was shorter than that in both subgroups of group II (P = 0.019, P b 0.001, Table B.2), but there was no significant difference observed between these two subgroups (P N 0.05, Table B.2). A larger amounts of intra-operative blood loss and drainage within 24 hours after operation were collected in group II compared with that in group I, but only drainage volume demonstrated significant difference between groups (P b 0.001).There were no significant differences in the proportion of transfusion of red blood cell, plasma or salvaged autologous blood between the two groups (P N 0.05). Likewise, there were no significant differences in the corresponding volume of transfusions between the two groups (P N 0.05). As for complications, patients in group II were more likely to develop hip complications (P = 0.031, Table B.1). No significant differences were noted in the occurrence rate of individual complication, overall complications and general medical complications between groups. Pulmonary embolism (PE), acute coronary syndrome, acute renal failure, gastroenteric stress ulcer, paralytic ileus and peripheral nerve injury were not observed in both groups. Univariate logistic regression analysis primarily identified risk factors for overall complications, general medical complications and hip complications. Only notable among these was the association of salvage THA with hip complications (OR = 3.18, 95%CI, 1.07–9.42, Table C.1). Multivariate logistic regression model determined the patient-based risk factors for the three outcome variables mentioned above and results were similar to univariate analysis. Patients in group II had increased risk of developing hip complications (OR = 4.15, 95%CI, 1.29–13.34, Table C.1).The Hosmer–Lemeshow goodness-of-fit test showed no evidence of a lack of fit for any characteristic analyzed in this study. Discussion Prior studies [21–23,28–30] mostly concerned outcomes of salvage THAs for failed IF such as prosthesis survival and function assessment compared with either elective osteoarthritic THAs or THAs due to proximal femur fracture. Our present study was to assess the immediate results of salvage THAs for patients with failed IF after FNF compared with those for acute displaced FNF and to determine whether salvage THA is an independent risk factor of perioperative complications. Although we hypothesized that individuals in group II would have poorer surgical outcomes than those in group I, we only observed prolonged operative time, larger amounts of drainage and increased risk of developing hip complications. Surgical efficiency, represented by decreased operative time, was reflected in group I (76.72 ± 24.85 min) compared with that in group II (99.77 ± 37.97 min) (not shown in tables). This is consistent with the findings of prior study [31] in which patients with failed IF had prolonged operative time (114.82 ± 32.13 min) in comparison with that in FNF group (90.63 ± 16.24 min) (P b 0.05). Since half of the patients in the salvage group underwent extraction of internal fixation devices, group II was divided into two subgroups and then compared with group I. As expected, similar result was found that the average operative time in group I was shorter than that in both subgroups of group II (P = 0.019, P b 0.001, Table C.1), but no significant difference between the two subgroups (P N 0.05, Table C.1). However, in Wang et al’s study [31], patients without hardware before THAs were not described, subgroup analysis was not mentioned either. The average operative time
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in group I (76.72 ± 24.85 min) was comparable to that (72.9 ± 9.5 min) in previous study conducted by Zeng et al [32]. But the patients included in the study were younger than age of sixty, accompanied with male to female proportion about one to one. As for longer operative time for patients with failed IF, potentially reasonable explanations could be those reviewed by Angelini et al [33] in 2009 and Petrie et al [34] in 2013 that disuse osteopenia, deformity, residual bony defect with removal of the original hardware in the proximal femur all pose technical challenges to successful reconstruction. Furthermore, because of absence of sclerotic subchondral bone typically present in elective osteoarthritic THAs instead of these salvage THAs, the insertion of cementless acetabular components may be difficult due to poor press-fit fixation. Accordingly acetabular reaming should be done carefully, making efforts to preserve the subchondral bone as possible and avoid forceful acetabular component impaction; and additional component fixation with screws might be performed when necessary. It has been reported that longer time for THA was associated with the elevation in relative risk of venous thromboembolism and greater probability of complications [35,36]. This information will be of value when advising patients about the risks of THA and managing them postoperatively. Unlike with our assumption, the mean intra-operative blood loss in group II was just slightly more than that in group I and no significant difference was observed between the two groups. This is inconsistent with findings of Wang et al’s study [31] in which there exists significant difference. As to drainage, patients with failed IF were more likely to get larger amounts compared to those with FNF. Plausible reasons for this could be scar healing and deformity with previous surgery, probably resulting in more surgical injuries [33]. The mean length of hospital stay (about twelve days) was relatively longer and not statistically different between the two groups in the current study. Other investigations [37–39] demonstrated that the length of stay ranged from about 4 to 9 days. This may be due to patient differences, medical resources, and discharge planning protocol of the hospital. In the current study, we comprehensively assessed complications to quantify the relative risk associated with salvage THA (VS primary THA) for patients with FNF using multivariate logistic regression analysis. Our findings suggest that patients with failed IF were at elevated risk of developing hip complications. This is consistent with previous findings [23] that patients with salvage THA were at increased risk of complications despite different durations of follow up. POVN is a common and critical problem that requests additional attention during perioperative period. Severe POVN may lead to adverse effects such as aspiration pneumonia, cardiovascular events or prolonged length of hospital stay and so on [40]. Therefore, it was extremely essential to include this into general medical complications. Increased operative time is one of the surgery related factors influencing POVN [40]. Presumably its occurrence rate could reflect the operative time to some degree in the present study. But no significant difference was found between the two groups. This may be influenced by other factors such as anesthetic types [40]. As for postoperative hematoma and fat liquefaction of incision, both are associated with increased risk of wound infection and included into hip complications [41]. Similarly, both occurred slightly often in group II although there was no statistical significance. It has been revealed by studies [23,42] that salvage THA for FNF had higher occurrence rate of dislocation, periprosthetic fracture, and superficial infections. In the current study, there was only one periprosthetic infection, one dislocation due to simple fall, one periprosthetic fracture with severe osteoporosis (with the corresponding P N 0.05). In a prospective cohort study of dislocation of THA in patients with FNF, Enocson et al [43] reported that posterolateral approach was associated with a significantly increased risk of dislocation. Although all of the THAs were performed through posterolateral approach in our study, the incidence rate of dislocation was low (1/130, 0.8%). The dislocation in THAs could also decrease with larger size of prosthetic femoral head [44,45]. About 86.2% patients in the present cohort adopted artificial
Please cite this article as: Yang Z, et al, Total Hip Arthroplasty for Failed Internal Fixation After Femoral Neck Fracture Versus That for Acute Displaced Femoral Neck Fracture: A Comparative Study, J Arthroplasty (2015), http://dx.doi.org/10.1016/j.arth.2015.02.037
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femoral heads with the diameter of 32 mm or greater. In addition, the lower incidence of dislocation in present study may be also partly due to shorter durations of follow up for this specific endpoint. There are several limitations to our present study. First, with a relatively small sample size, our study is underpowered to determine true differences of individual complication between the two groups, however, it still represents one of the larger series reported so far in the literature. Second, American Society of Anesthesiologists (ASA) score as a measure of general health status, related to immediate postoperative complication, was not included in the multivariate analysis. Third, combination of clinical result and function evaluation could comprehensively evaluate the treatment outcome of salvage THA. However, in current study, postoperative function was not assessed for this cohort of patients since it was not recorded in our database, which makes our present study imperfect. In conclusion, present study suggested that salvage THA for failed IF following FNF was a more technically demanding procedure with prolonged operative time and larger amounts of postoperative drainage (within 24 hours), and was at increased risk of developing hip complications compared to primary THA for acute displaced FNF. These increased risks should be paid much attention to, not only for choosing the appropriate treatment option, but also for providing effective perioperative care. Appendix A
Table A.1 Patient Demographics and Preoperative Characteristics.
No. Age ≥60, b70 ≥70, b80 ≥80 Gender Male Female Weight Height BMI in kg/m2 b18.5 ≥18.5, ≤23.9 ≥24.0, ≤27.9 ≥28 Deyo index 0 1 2 3 or more
Group I
Group II
64 71.3 ± 6.1 27 (42.2%) 32 (50.0%) 5 (7.8%)
66 69.6 ± 6.5 35 (53.0%) 26 (39.4%) 5 (7.6%)
13 (20.3%) 51 (79.7%) 56.8 ± 11.4 Kg 159 ± 7.2 cm 22.0 ± 4.7 5 (7.8%) 41 (64.1%) 15 (23.4%) 3 (4.7%)
24 (36.4%) 42 (63.6%) 59.9 ± 10.6 Kg 161 ± 7.3 cm 22.9 ± 2.8 6 (9.1%) 39 (59.1%) 18 (27.3%) 3 (4.5%)
39 (60.9%) 19 (29.7%) 3 (4.7%) 3 (4.7%)
48 (72.7%) 13 (19.7%) 5 (7.6%) 0 (0.0%)
P Value N0.05
N0.05
N0.05 N0.05 N0.05
N0.05
Data are displayed using means ± SD or n (%); group I represents primary THAs for acute displaced femoral neck fracture while group II represents salvage THAs for failed internal fixation after femoral neck fracture. Table B.1 Comparison of Outcomes During Perioperative Period Between Groups. Outcomes
Group I
Group II
P Value
Length of stay Pre-LOS Post-LOS Blood loss (intra-) Transfusion proportion Red blood cell Transfusion proportion Plasma Transfusion proportion Autologous blood 24 h drain Overall complications General medical complications PONV DVT Urinary retention Urinary tract infection Pneumonia Respiratory tract infection Hip complications Fat liquefaction of incision Hematoma Dislocation Infection Periprosthetic fracture
12.89 ± 5.51 d 5.91 ± 4.43 d 6.98 ± 2.71 d 232.34 ± 125.80 ml 30/64 (46.9%) 406.67 ± 493.18 ml 15/64 (23.4%) 463.33 ± 315.93 ml 11/64 (17.2%) 114.09 ± 99.07 ml 231.80 ± 159.01 ml 18 (28.13%) 15 (23.44%) 3 (4.69%) 3 (4.69%) 1 (1.56%) 2 (3.13%) 3 (4.69%) 4 (6.25%) 5 (7.81%) 1 (1.56%) 3 (4.69%) 1(1.56%) 0 (0.0%) 0 (0.0%)
12.06 ± 5.40 d 5.33 ± 3.15 d 6.73 ± 3.20 d 253.64 ± 171.95 ml 28/66 (42.4%) 428.57 ± 352.09 ml 14/66 (21.2%) 467.86 ± 331.44 ml 10/66 (15.2%) 145.00 ± 72.46 ml 392.27 ± 241.49 ml 25 (37.88%) 13 (19.70%) 7 (10.61%) 2 (3.03%) 2 (3.03%) 0 (0.0%) 0 (0.0%) 3 (4.55%) 14 (21.21%) 5 (7.50%) 7 (10.61%) 0 (0.0%) 1 (1.52%) 1 (1.52%)
N0.05 N0.05 N0.05 N0.05 N0.05 N0.05 N0.05 N0.05 N0.05 N0.05 b0.001⁎ N0.05 N0.05 N0.05 N0.05 N0.05 N0.05 N0.05 N0.05 0.031* N0.05 N0.05 N0.05 N0.05 N0.05
Data are displayed using means ± SD or n (%); LOS is short for length of stay; group I represents primary THAs for acute displaced femoral neck fracture while group II represents salvage THAs for failed internal fixation after femoral neck fracture; * means the difference is significant at the 0.05 level. Individual complication was calculated according to number of cases while summary complications were calculated according to number of patients.
Please cite this article as: Yang Z, et al, Total Hip Arthroplasty for Failed Internal Fixation After Femoral Neck Fracture Versus That for Acute Displaced Femoral Neck Fracture: A Comparative Study, J Arthroplasty (2015), http://dx.doi.org/10.1016/j.arth.2015.02.037
Z. Yang et al. / The Journal of Arthroplasty xxx (2015) xxx–xxx
5
Table B.2 Multiple Comparison of Operative Time Using LSD’s Post Hoc Test. Mean(I, 95%CI)(minute)
Group(J)
Mean Difference(I-J,95%CI)
P Value
a
Group(I)
34
106.03 (94.86–117.19)
b
32
93.12 (77.64–108.61)
c
64
76.72 (70.51–82.93)
b c a c a b
12.91 (−2.68 to 28.49) 29.31⁎ (15.87 to 42.75) −12.91 (−28.49 to 2.68) 16.40⁎ (2.71 to 30.11) −29.31⁎ (−42.75 to −15.87) −16.40⁎ (−30.11 to −2.71)
PN Pb PN P= Pb P=
130
88.42 (82.51–94.34)
Total
No.(I)
0.05 0.001 0.05 0.019 0.001 0.019
Group “a” represents patients in salvage group with hardware retained in the lesion; “b” represents those without hardware, “c” for patients with primary THA in group I; each asterisk means the difference is significant.
Table C.1 Univariate and Multivariate Analysis for Risk Factors of complications. Univariate Analysis Outcome/Risk Factor General medical complication Salvage VS primary THA Age 60–70 Age 70–80 Age 80 or older Male VS female Body mass index in kg/m2 BMI ≥24 VS BMI b24 Comorbidity Presence VS absence Hip complication Salvage VS primary THA Age 60–70 Age 70–80 Age 80 or older Male VS female Body mass index in kg/m2 BMI ≥24 VS BMI b24 Comorbidity Presence VS absence Overall complication Salvage VS primary THA Age 60–70 Age 70–80 Age 80 or older Male VS female Body mass index in kg/m2 BMI ≥24 VS BMI b24 Comorbidity Presence VS absence
Multivariate Analysis
OR
95%CI
Adjusted OR
95%CI
0.80
0.35–1.85
0.77
0.32–1.86
0.98 1.62 0.80
0.41–2.38 0.37–7.13 0.31–2.08
0.85 1.68 0.96
0.34–2.11 0.36–7.85 0.35–2.65
0.44
0.15–1.24
0.44
0.15–1.30
0.77
0.31–1.91
0.74
0.28–1.97
3.18
1.07–9.42
4.15
1.29–13.34⁎
0.81 2.52 0.63
0.28–2.33 0.55–11.61 0.20–2.04
0.96 2.68 0.39
0.32–2.89 0.52–13.70 0.11–1.41
1.01
0.38–3.12
1.09
0.35–3.36
1.58
0.58–4.27
2.13
0.70–6.51
1.56
0.75–3.26
1.86
0.84–4.12
1.19 3.67 0.67
0.55–2.59 0.92–14.56 0.30–1.56
1.21 3.94 0.58
0.54–2.69 0.93–16.79 0.23–1.44
0.61
0.26–1.40
0.63
0.26–1.53
1.13
0.52–2.44
1.25
0.54–2.89
OR N1 indicates salvage total hip arthroplasties (THAs) are at increased risk of the complications compared with primary THAs for femoral neck fracture, whereas OR b1 indicates salvage THAs are at decreased risk of the complications. The corresponding 95% confidence intervals (CI) reveal that the result is statistically significant when ‘1’ is not included in the interval, whereas when ‘1’ is included in the interval, the result is not statistically significant.
Acknowledgements All authors agree to list H. Liu as a co-first author, who made major contributions to the writing of the revised manuscript.
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Please cite this article as: Yang Z, et al, Total Hip Arthroplasty for Failed Internal Fixation After Femoral Neck Fracture Versus That for Acute Displaced Femoral Neck Fracture: A Comparative Study, J Arthroplasty (2015), http://dx.doi.org/10.1016/j.arth.2015.02.037
