Five to Ten-Year Results of the Birmingham Hip Resurfacing Implant in the U.S.: A Single Institution's Experience.

BACKGROUND: International surgeon series and registry data have demonstrated positive outcomes and long-term survival of the Birmingham Hip Resurfacing (BHR) implant. We report the 5 to 10-year results from a single center in the U.S. METHODS: Three hundred and fourteen patients (360 hips) underwent surface replacement arthroplasty with use of the BHR implant and consented to study participation. Patient-reported outcomes and complication and revision data were collected at a minimum of 5 years of follow-up for 93% (324 of 350) of the hips in surviving patients. A matched-cohort analysis was used to compare clinical outcomes between use of the BHR and total hip arthroplasty. RESULTS: Mean modified Harris hip score (mHHS) and University of California, Los Angeles (UCLA) scores significantly improved postoperatively, to 89.9 and 8.0, respectively (p < 0.001). The Kaplan-Meier estimated rate of survival for all-cause revision was 97.2% (95% confidence interval [CI], 94.7% to 98.5%) and 93.8% (95% CI, 88.8% to 96.7%) at 5 and 10 years, respectively. In a subgroup analysis of patients fitting our current BHR inclusion criteria (males <60 years of age with a diagnosis of osteoarthritis and anatomy conducive to a femoral head component of ≥48 mm), survival free of aseptic revision was 99.5% (95% CI, 96.6% to 99.9%) at 5 years and 98.2% (95% CI, 94.4% to 99.4%) at 10 years. Fourteen patients (4.3% of all hips) required revision. Postoperative UCLA scores were significantly greater for BHR compared with total hip arthroplasty (mean score of 8.0 ± 2.0 versus 7.6 ± 1.8; p = 0.040) in a matched-cohort analysis, with patients matched according to preoperative UCLA score, diagnosis, age, sex, and body mass index. Among matched patients who were highly active preoperatively (UCLA score of 9 to 10), BHR provided a smaller median decrease in the postoperative UCLA score (0.0 versus 1.0; p < 0.001), which was clinically important according to the minimal clinically important difference (MCID, 0.92). Furthermore, BHR provided a greater likelihood of remaining highly active compared with total hip arthroplasty (61% compared with 20%; p < 0.001). CONCLUSIONS: BHR demonstrated excellent survivorship and clinical outcomes at 5 to 10 years in selected patients. As compared with total hip arthroplasty, the use of the BHR may provide highly active patients with clinically important advantages in postoperative activity as well as a greater likelihood of remaining highly active. Continued follow-up is necessary to validate long-term BHR outcomes. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

High Rate of Failure After Revision of a Constrained Liner.

BACKGROUND: The purpose of this study was to examine the outcomes of repeat revision after failure of a constrained liner. METHODS: We reviewed 1212 consecutive revisions and identified 74 (6%) revisions of a failed constrained liner in 46 patients with a mean age of 65 years. The most common reasons for revision of a constrained liner were recurrent instability (64.9%) and infection (25.7%). RESULTS: At a mean of 35 months, 42 of the 74 hips (57%) required repeat revision. Kaplan-Meier revision-free survival was 24% at 10 years. Thirty-two of the 74 revisions (43%) had a dislocation event after the index revision. Kaplan-Meier dislocation-free survival was 43% at 10 years. There was a higher failure rate among the 34 patients with abductor deficiency (hazard ratio 1.90, 95% confidence interval, 1.06-3.43; P = .032). CONCLUSION: Patients undergoing revision of a failed constrained liner have a high likelihood of recurrent dislocation and repeat revision surgery. LEVEL OF EVIDENCE: Level IV.

Acetabular Focal Chondral Lesions Are Not Associated With Worse Outcomes After Periacetabular Osteotomy: A Matched Group Analyses.

BACKGROUND: The purpose of this study was to assess the outcomes of patients who underwent combined hip arthroscopy and periacetabular osteotomy with acetabular focal chondral defects and compare these outcomes with a group of patients without focal chondral defects. METHODS: A retrospective review looking at patients who underwent hip arthroscopy and/or periacetabular osteotomy was performed. Minimum 2-year follow-up, Tönnis grade 0-1, and a Beck chondromalacia stages 4-5 were included. Twenty-eight hips met inclusion criteria. These patients were then matched 1:1 and compared. RESULTS: The average acetabular chondral defect size was 144.3 mm2 ± standard deviation 116.2. Postoperative, modified Harris Hip Score, Hip Disability and Osteoarthritis Outcome Score, and University of California Los Angeles scores were similar between groups (P = .382, P = .755, P = .763, respectively). At the last follow-up, Tönnis grade was similar between groups (P = .552). No association between having a defect and increased risk of failure was noted (hazard ratio 1.35 [95% CI 0.43-4.24], P = .607). CONCLUSION: We found that patients with focal chondral defects did similar to a comparison group of patients without chondral defects.

Do Mortality and Complication Rates Differ Between Periprosthetic and Native Hip Fractures?

BACKGROUND: Epidemiological estimates indicate a rising incidence of periprosthetic hip fractures. While native hip fractures are known to be a highly morbid condition, a significant body of research has led to improved outcomes and decreased complications following these injuries. Comparatively, little research has evaluated the relative morbidity and mortality of periprosthetic hip fractures. The purpose of this study was to compare the morbidity and mortality of periprosthetic vs native hip fractures. METHODS: Using the National Surgical Quality Improvement Program (NSQIP) database, 523 periprosthetic hip fractures were matched to native hip fractures using propensity scores. The 30-day rates of complications were compared using McNemar's test. A multivariate regression was then used to determine independent risk factors for mortality following periprosthetic fracture. RESULTS: Mortality was similar between groups (periprosthetic: 2.7% vs native: 3.4%; P = .49). Periprosthetic fractures exhibited a greater rate of overall (63.1% vs 38.6%; P < .001) and minor complications (59.1% vs 34.4%; P < .001). There was an increased rate of return to the operating room (7.8% vs 3.1%; P < .001) and blood transfusion in the periprosthetic group (54.9% vs 30.2%; P = .001). Age greater than 85 (odds ratio 9.21) and dependent functional status (odds ratio 5.38) were both independent risk factors for mortality following periprosthetic fracture. CONCLUSIONS: While native hip fractures are known to be highly morbid, our findings suggest that periprosthetic hip fractures have a similar mortality with significantly higher short-term morbidity. Future research is warranted to better understand risk factors and prevention strategies for complications in this subset of patients.

Revision Total Hip Arthroplasty With a Monoblock Splined Tapered Grit-Blasted Titanium Stem.

BACKGROUND: In revision total hip arthroplasty (THA), proximal femoral bone loss creates a challenge of achieving adequate stem fixation. The purpose of this study was to examine the outcomes of a monoblock, splined, tapered femoral stem in revision THA. METHODS: Outcomes of revision THA using a nonmodular, splined, tapered femoral stem from a single surgeon were reviewed. With a minimum of 2-year follow-up, there were 68 cases (67 patients). Paprosky classification was 3A or greater in 85% of the cases. Preoperative and postoperative Harris Hip Scores (HHS), radiographic subsidence and osseointegration, limb length discrepancy, complications, and reoperations were analyzed. RESULTS: The Harris Hip Score improved from 37.4 ± SD 19.4 preoperatively to 64.6 ± SD 21.8 at final follow-up (P < .001). There were 16 revision procedures-8 for septic indications and 8 for aseptic indications. Subsidence occurred at a rate of 3.0% and dislocation at 7.4%. Limb length discrepancy of more than 1 cm after revision was noted in 13.6% of patients. Bone ingrowth was observed in all but 4 patients (94.1%). At 4-year follow-up, Kaplan-Meier estimated survival was 72.9% (95% confidence interval [CI] 57.0-83.8) for all causes of revision, 86.6% (95% CI 72.0-93.9) for all aseptic revision, and 95.5% (95% CI 86.8-98.5) for aseptic femoral revision. CONCLUSION: Although complications were significant, revision for femoral aseptic loosening occurred in only 3 patients. Given the ability of this monoblock splined tapered stem to adequately provide fixation during complex revision THA, it remains a viable option in the setting of substantial femoral bone defects.

Medial Gastrocnemius Flap in the Course of Treatment for an Infection at the Site of a Total Knee Arthroplasty.

INTRODUCTION: The pedicled medial gastrocnemius flap provides a robust coverage option for most soft-tissue deficiencies over the distal anterior aspect of the knee encountered in the setting of an infection after total knee arthroplasty. STEP 1 PATIENT POSITIONING: Position the patient supine with an ipsilateral sterile thigh tourniquet to allow room for harvest of a split-thickness skin graft as needed. STEP 2 REVISION ARTHROPLASTY FOR INFECTION: Perform the arthroplasty to address the underlying deep infection (e.g., irrigation and debridement with exchange of modular components, component removal with antibiotic spacer placement, antibiotic spacer exchange, or second-stage reimplantation) prior to the medial gastrocnemius flap that is utilized for soft-tissue coverage. STEP 3 INCISION AND APPROACH FOR THE MEDIAL GASTROCNEMIUS FLAP: Use one of two different surgical approaches for the exposure and elevation of the medial gastrocnemius muscle and the identification of its vascular pedicle: the medial approach or the posterior midline approach. STEP 4 ELEVATION OF THE MEDIAL GASTROCNEMIUS FLAP: Protect the sural artery pedicle in the popliteal fossa because it is key to raising a viable medial gastrocnemius flap. STEP 5 TRANSPOSITION AND INSETTING OF THE FLAP OVER THE DEFECT: Rotate the flap and transpose it anteriorly over the defect either through a subcutaneous tunnel or by dividing the intervening skin bridge. STEP 6 CLOSURE SKIN-GRAFTING AND DRESSING APPLICATION: Complete the layered skin closure and place a split-thickness skin graft over the remaining exposed muscle flap and a nonadherent compressive bolster dressing or negative-pressure device over the skin graft to prevent hematoma under the skin graft. STEP 7 POSTOPERATIVE CARE: Progress range of motion of the knee once the flap and graft show evidence of survival, while an appropriate antibiotic regimen is completed. RESULTS: We recently reported the largest English-language series, to our knowledge, of medial gastrocnemius flaps performed for soft-tissue coverage in the course of treatment for infection after total knee arthroplasty13.

Femoroacetabular Impingement and Pelvic Incidence: Radiographic Comparison to an Asymptomatic Control.

PURPOSE: To investigate whether pelvic incidence (PI) in patients with symptomatic femoroacetabular impingement was different from that in a normal population. METHODS: Retrospective analysis of 30 consecutive female and 30 consecutive male patients with computed tomography scans who underwent hip arthroscopy for FAI. PI was measured using scout lateral radiographs. The center-edge angle (CEA), acetabular version, and α angle were also measured. Each patient was subcategorized as having a cam-type deformity (α angle >55°), a deep socket deformity (CEA >39°), and/or a retroverted acetabulum (acetabular anteversion <15°). Our group and subgroups were compared with a historical control group from a previously published study of 300 volunteers. Each group was compared using a Student t test. RESULTS: Our mean PI was 49.31° ± 12.34° (range, 28.4°-79.5°), less than the asymptomatic historical control (n = 300) with a mean PI of 55.0° ± 10.6° (range, 33°-82°) (P < .001). The subgroups for cam deformity, deep socket deformity, and acetabular retroversion have a mean PI of 48.89° ± 11.81°, 38.30° ± 7.56°, and 44.93° ± 11.32°, respectively. All had a significantly lower PI than the historical control (P < .001, P < .001, P < .001, respectively). CONCLUSIONS: We conclude that patients presenting with FAI may have a lower PI than the general population. The clinical significance of a 5.7° difference in PI remains unknown. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Return to Golf After Lumbar Fusion.

BACKGROUND: Spinal fusion surgery is being increasingly performed, yet few studies have focused on return to recreational sports after lumbar fusion and none have specifically analyzed return to golf. HYPOTHESIS: Most golfers successfully return to sport after lumbar fusion surgery. STUDY DESIGN: Case series. LEVEL OF EVIDENCE: Level 4. METHODS: All patients who underwent 1- or 2-level primary lumbar fusion surgery for degenerative pathologies performed by a single surgeon between January 2008 and October 2012 and had at least 1-year follow-up were included. Patients completed a specifically designed golf survey. Surveys were mailed, given during follow-up clinic, or answered during telephone contact. RESULTS: A total of 353 patients met the inclusion and exclusion criteria, with 200 responses (57%) to the questionnaire producing 34 golfers. The average age of golfers was 57 years (range, 32-79 years). In 79% of golfers, preoperative back and/or leg pain significantly affected their ability to play golf. Within 1 year from surgery, 65% of patients returned to practice and 52% returned to course play. Only 29% of patients stated that continued back/leg pain limited their play. Twenty-five patients (77%) were able to play the same amount of golf or more than before fusion surgery. Of those providing handicaps, 12 (80%) reported the same or an improved handicap. CONCLUSION: More than 50% of golfers return to on-course play within 1 year of lumbar fusion surgery. The majority of golfers can return to preoperative levels in terms of performance (handicap) and frequency of play. CLINICAL RELEVANCE: This investigation offers insight into when golfers return to sport after lumbar fusion surgery and provides surgeons with information to set realistic expectations postoperatively.

Does Hip Arthroscopy Affect the Outcomes of a Subsequent Total Hip Arthroplasty?

BACKGROUND: Hip arthroscopy utilization is on the rise in the United States. Thus, determining the impact of prior hip arthroscopy on subsequent total hip arthroplasty (THA) is important to understand. METHODS: A retrospective review of a high-volume orthopedic surgery practice's billing database yielded 42 hip arthroscopies that underwent subsequent THA. An age-, sex-, and body mass index (2:1)-matched cohort of primary THAs was used for comparison. RESULTS: No difference was observed in the postoperative Harris Hip Score between groups (92.1 ± 10.9 vs 90.1 ± 6.6, P = .20); however, there was greater overall improvement in Harris Hip Score in the control group (40.4 ± 18.4 vs 45.1 ± 8.7, P = .05). There were no differences observed in the complication (P = .5) or revision rates (P = .4). CONCLUSION: With the numbers available, prior hip arthroscopy does not appear to have an impact on the functional outcomes of a subsequent THA.

Radiographic Comparison of Anterior Acetabular Rim Morphology Between Pincer Femoroacetabular Impingement and Control.

PURPOSE: To define and compare 3 new parameters (anterior rim angle [ARA], anterior wall angle [AWA], and anterior margin ratio [AMR]), in addition to the lateral center-edge angle of Wiberg and the Tönnis angle, for measuring pincer-type femoroacetabular impingement (FAI) in an asymptomatic versus symptomatic FAI population. METHODS: We reviewed anteroposterior pelvis radiographs of patients verified to have no hip complaints between December 2009 and December 2011. We also reviewed anteroposterior pelvis radiographs of patients who underwent a rim-trimming procedure for pincer FAI between December 2010 and December 2011. Patients aged older than 65 years or younger than 18 years were excluded. Radiographs with a Tönnis grade of 2 or greater were also excluded. For the group of patients with symptomatic hip impingement, radiographs that did not have a crossover sign were excluded. The 2 cohorts were matched for age, sex, and body mass index. Measurements included the Tönnis angle, lateral center-edge angle of Wiberg, ARA, AWA, and AMR. These measurements were compared between the groups. RESULTS: Seventy-two asymptomatic hips were measured. There were 44 female patients (61%) and 28 male patients (39%), aged 25 to 51 years, in the asymptomatic group. The mean ARA was 88.91° ± 8.06°, the mean AWA was 34.89° ± 8.09°, and the mean AMR was 0.49 ± 0.15. Seventy-two symptomatic hips were measured. There were 40 female patients (56%) and 32 male patients (44%), aged 27 to 58 years, in the symptomatic group. The mean ARA was 82.98° ± 10.82°, the mean AWA was 39.11° ± 9.00°, and the mean AMR was 0.56 ± 0.14. The mean difference in the ARA between asymptomatic patients and symptomatic patients was 5.92° (P = .0001). The mean difference in the AWA was 4.22° (P = .0019). The mean difference in the AMR was 0.07 (P = .0039). CONCLUSIONS: Our study provides information on several measurements within an asymptomatic cohort and a symptomatic cohort. Although we found statistically significant differences between the 2 populations, the clinical significance remains unknown. We recommend using this asymptomatic population as a guideline for limits on resection of the anterior acetabular rim. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

A Novel Complication of the Dall-Miles Cable Grip System Mimicking Recurrent Synovial Chondromatosis: A Case Report and Review of the Literature.

CASE: A 25-year-old man with synovial chondromatosis of the hip was treated with a synovectomy through a transtrochanteric approach; the repair was made with use of a Dall-Miles cable. Approximately 13 years later, the patient returned with a massive bursal reaction and a cyst containing "rice bodies." Although the physical examination and imaging were suggestive of recurrent synovial chondromatosis, the bursal reaction actually represented a novel complication of the Dall-Miles system. CONCLUSION: When a patient who has had prior orthopaedic instrumentation presents with pain and imaging that demonstrates formation of a bursal cyst, a cyst containing rice bodies secondary to bursal irritation by the implant should be considered.

Prevalence of Cam Morphology in Females with Femoroacetabular Impingement.

Cam and pincer are two common morphologies responsible for femoroacetabular impingement (FAI). Previous literature has reported that cam deformity is predominantly a male morphology, while being significantly less common in females. Cam morphology is commonly assessed with the alpha angle, measured on radiographs. The purpose of this study is to determine the prevalence of cam morphology utilizing the alpha angle in female subjects diagnosed with symptomatic FAI. All females presenting to the senior author's clinic diagnosed with symptomatic FAI between December 2006 and January 2013 were retrospectively reviewed. Alpha (α) angles were measured on anteroposterior and lateral (Dunn 90°, cross-table lateral, and/or frog-leg lateral) plain radiographs by two blinded physicians, and the largest measured angle was used. Using Gosvig et al.'s classification, alpha angle was characterized as (pathologic > 57°), borderline (51-56°), subtle (46-50°), very subtle (43-45°), or normal (≤42°). Three hundred and ninety-one patients (438 hips) were analyzed (age 36.2 ± 12.3 years). Among the hips included, 35.6% were normal, 14.6% pathologic, 15.1% borderline, 14.6% subtle, and 20.1% very subtle. There was no correlation between alpha angle and patient age (R = 0.17) or body mass index (R = 0.05). The intraclass correlation coefficient for α-angle measurements was 0.84. Sixty-four percent of females in this cohort had an alpha angle >42°. Subtle cam deformity plays a significant role in the pathoanatomy of female patients with symptomatic FAI. As the majority of revision hip arthroscopies are performed due to incomplete cam correction, hip arthroscopists need to be cognizant of and potentially surgically address these subtle lesions.

Techniques and Results for Open Hip Preservation.

While hip arthroscopy grows in popularity, there are still many circumstances under which open hip preservation is the most appropriately indicated. This article specifically reviews open hip preservation procedures for a variety of hip conditions. Femoral acetabular impingement may be corrected using an open surgical hip dislocation. Acetabular dysplasia may be corrected using a periacetabular osteotomy. Acetabular protrusio may require surgical hip dislocation with rim trimming and a possible valgus intertrochanteric osteotomy. Legg-Calve-Perthes disease produces complex deformities that may be better served with osteotomies of the proximal femur and/or acetabulum. Chronic slipped capital femoral epiphysis may also benefit from a surgical hip dislocation and/or proximal femoral osteotomy.

An Analysis of Risk Factors for Short-Term Complication Rates and Increased Length of Stay Following Unicompartmental Knee Arthroplasty.

BACKGROUND: Unicompartmental knee arthroplasty (UKA) is an increasingly popular procedure, with excellent long-term outcomes. However, there are only a limited number of reports reporting its short-term morbidity and mortality. QUESTIONS/PURPOSES: We sought to analyze the reported 30-day morbidity, mortality, and risk factors for complications and prolonged length of stay (>4 days) following UKA. PATIENTS AND METHODS: Utilizing the National Surgical Quality Improvement Program (NSQIP) database, including patients (n = 2316) from 2005-2012, we correlated the reported 30-day complications and prolonged length of stay with patient demographics and risk factors. RESULTS: The overall rate of complications was low (3.2%). The distribution of complications demonstrated 0.5% major systemic, 1.4% minor systemic, 0.7% major local, and 0.9% minor local complications, with a 2.1% readmission rate. Multivariate regression demonstrated increased BMI and a history of chronic obstructive pulmonary disease (COPD) as independent risk factors for complications. Furthermore, multivariate regression demonstrated increased BMI, ASA ≥ 3, history of COPD, recent operation, and postoperative transfusion as independent risk factors for prolonged length of hospitalization. CONCLUSIONS: Utilizing the NSQIP, we present one of the largest studies to date evaluating complications following UKA. Our multivariate model demonstrated obesity and COPD to be the risk factors for complications while obesity, ASA ≥ 3, COPD, recent operation, and blood transfusion to be the risk factors for prolonged length of stay.

Does Neuraxial Anesthesia Decrease Transfusion Rates Following Total Hip Arthroplasty?

Perioperative transfusions increase complications and cost following THA. Current series evaluating neuraxial anesthesia and blood loss following THA are small and utilize heterogeneous populations. Using the NSQIP database we compared transfusion rates following THA with neuraxial and general anesthesia. Between 2005 and 2012, 28,857 THAs (11,317 neuraxial anesthesia) were identified. Univariate analysis showed lower rates of transfusion, pneumonia, unplanned intubation, prolonged intubation, stroke, all complications, and medical complications in the neuraxial group. Operative time and length of stay were shorter with neuraxial anesthesia as well. After adjusting for patient comorbidities, a multivariate regression model showed fewer transfusions with neuraxial anesthesia. The multivariate regression model showed additional independent risk factors for transfusion including gender, operative time, elevated INR, and a history of hypertension, metastatic cancer, and renal failure.

Bilateral extensor mechanism disruption after total knee arthroplasty in two morbidly obese patients.

Disruption of the extensor mechanism as a result of patellar tendon or quadriceps tendon rupture is an uncommon but devastating complication after total knee arthroplasty. Treating a disrupted extensor mechanism can be challenging, particularly in patients who are morbidly obese, due to an increased risk of postoperative complications. Therefore, despite the debilitating nature of extensor mechanism disruption, many community surgeons do not feel comfortable pursuing more complex cases like revision total knee arthroplasty with extensor mechanism allograft on morbidly obese patients, and consequently many of these patients are referred to tertiary-care centers for reconstruction secondary to the complexity of this patient cohort. The authors report 2 cases of bilateral extensor mechanism disruption after total knee arthroplasty in patients who are morbidly obese. One patient experienced trauma leading to her initial rupture; however, her contralateral atraumatic disruption was subsequently diagnosed at a later date. The second patient did not experience trauma leading to either of her extensor mechanism disruptions. Despite substantial medical comorbidities and morbid obesity, revision total knee arthroplasties with extensor mechanism allografts were recommended in both cases in a staged bilateral fashion. The surgical technique is described and the unique challenges afforded by the marked obesity are detailed. The current literature on this subject is reviewed. Despite early complications related to recumbency, this report serves as an example of successful repairs of extensor mechanism disruptions in patients who are morbidly obese, suggesting that extensor mechanism allograft is viable even in patients with high risk of complications.

The False-Profile View May Be Used to Identify Cam Morphology.

PURPOSE: To identify the accuracy of measuring the alpha angle on the false-profile, anteroposterior (AP), and 90° Dunn lateral views of the hip as compared with computed tomography (CT) scan findings. METHODS: Forty patients were needed to have power greater than 80%. Forty-five consecutive patients undergoing hip arthroscopy were retrospectively reviewed with preoperative radial oblique CT reformatted scans and plain radiographs. Alpha angles were measured on plain radiographs (AP, 90° Dunn lateral, and false profile) and CT reformatted views. Abnormal alpha angles were considered greater than 50.5°. Two orthopaedic surgeons independently measured the images, and the results were compared between imaging modalities. RESULTS: The false-profile view was 60% sensitive and 89.0% specific for diagnosing cam deformities of the hip. All radiographs combined were 86% sensitive and 75% specific for diagnosing cam deformities. The false-profile view most strongly correlated with the 2-o'clock (R = 0.746, P = .001) and 3-o'clock (R = 0.698, P < .0001) positions. An intraclass correlation coefficient of 0.81 was found for measurement of the alpha angle on the false-profile view. CONCLUSIONS: This study has proved that the false-profile view effectively characterizes cam deformity, especially anterior deformity at the 3-o'clock position. Measuring the alpha angle on the false-profile view appears to be reproducible. The false-profile view along with standing AP pelvis and 90° Dunn lateral views of the hip comprises a good screening radiographic series for patients presenting with symptoms of femoroacetabular impingement. LEVEL OF EVIDENCE: Level III, diagnostic study.

Do Complication Rates Differ by Gender After Metal-on-metal Hip Resurfacing Arthroplasty? A Systematic Review.

BACKGROUND: Although metal-on-metal (MoM) bearing surfaces provide low rates of volumetric wear and increased stability, evidence suggests that certain MoM hip arthroplasties have high rates of complication and failure. Some evidence indicates that women have higher rates of failure compared with men; however, the orthopaedic literature as a whole has poorly reported such complications stratified by gender. QUESTIONS/PURPOSES: This systematic review aimed to: (1) compare the rate of adverse local tissue reaction (ALTR); (2) dislocation; (3) aseptic loosening; and (4) revision between men and women undergoing primary MoM hip resurfacing arthroplasty (HRA). METHODS: Systematic MEDLINE and EMBASE searches identified all level I to III articles published in peer-reviewed journals, reporting on the outcomes of interest, for MoM HRA. Articles were limited to those with 2-year followup that reported outcomes by gender. Ten articles met inclusion criteria. Study quality was evaluated using the Modified Coleman Methodology Score; the overall quality was poor. Heterogeneity and bias were analyzed using a Mantel-Haenszel statistical method. RESULTS: Women demonstrated an increased odds of developing ALTR (odds ratio [OR], 5.70 [2.71-11.98]; p<0.001), dislocation (OR, 3.04 [1.2-7.5], p=0.02), aseptic loosening (OR, 3.18 [2.21-4.58], p<0.001), and revision (OR, 2.50 [2.25-2.78], p<0.001) after primary MoM HRA. CONCLUSIONS: A systematic review of the currently available literature reveals a higher rate of complications (ALTR, dislocation, aseptic loosening, and revision) after MoM HRA in women compared with men. Although femoral head size has been frequently implicated as a prime factor in the higher rate of complication in women, further research is necessary to specifically probe this relationship. Retrospective studies of data available (eg, registry data) should be undertaken, and moving forward studies should report outcomes by gender (particularly complications). LEVEL OF EVIDENCE: Level III, therapeutic study.