Faculty Bibliography

BACKGROUND:As interest in hip resurfacing arthroplasty (HRA) expands to complex pathologies, developmental dysplasia of the hip (DDH) has emerged as a challenging but increasingly considered indication. Although severe DDH often precludes resurfacing because of distorted anatomy, mild cases (Crowe I and II) may provide favorable conditions. This review evaluates outcomes of HRA in mild DDH, compares them with outcomes of total hip arthroplasty (THA) in DDH and HRA in primary osteoarthritis (OA) and assesses the potential of HRA to improve long-term function in this population. METHODS:A systematic search of PubMed, Embase, and Scopus identified studies reporting outcomes of HRA in DDH. Titles and abstracts were screened, followed by full-text review. Data on demographics, outcomes, and radiographic findings were extracted. Pooled complication and survivorship rates were calculated. A random-effects meta-analysis compared revision risk in HRA-treated patients with DDH vs. OA, and in patients with DDH treated with HRA vs. THA. Statistical significance was defined as a 95% confidence interval (CI) excluding 1. A separate meta-analysis compared mean postoperative flexion in patients with DDH treated with HRA vs. THA, with significance defined as a 95% CI excluding 0. RESULTS:From 65 screened articles, 11 met inclusion criteria, totaling 895 patients and 1,006 hips with DDH. The mean age was 45.26 years, with an average follow-up of 7.06 years. The pooled survivorship was 93%, and the complication rate was 13%. No significant difference in revision risk was found between DDH and OA HRA cohorts, or between HRA and THA in DDH, although both trends favored OA and THA. Patients with HRA-treated DDH had significantly greater postoperative flexion (standardized mean difference -1.21, 95% CI -1.54 to -0.87). CONCLUSION/CONCLUSIONS:Despite anatomical challenges and a potential for higher revision or complication rates in patients with DDH, mid-term outcomes, including patient-reported outcome, were comparable with those in primary osteoarthritis and THA cohorts. This review supports the selective use of HRA in patients with Crowe I and II DDH, particularly when modern surgical techniques and DDH-specific implants are used. LEVEL OF EVIDENCE/METHODS:Level III, systematic review of Level I, III, and IV studies. See Instructions for Authors for a complete description of levels of evidence.

BACKGROUND:Hip resurfacing arthroplasty (HRA) is considered a highly complex procedure, requiring advanced specialization and training beyond that of conventional total hip arthroplasty (THA). With the advent of computer-assisted navigation in HRA, some surgeons have adopted this technology to improve accuracy, whereas others continue to rely on traditional mechanical jig techniques. This study aims to assess radiographic positioning data and clinical outcomes to evaluate the effectiveness of computer-assisted navigation in HRA. METHODS:A literature search was conducted using PubMed, Embase, and Scopus databases with specific search terms related to HRA, computer navigation, and outcomes. Data extraction focused on demographic and study variables such as complication rates, radiographic data, and patient-reported outcomes. A meta-analysis was performed using a random effects model to compare operative time, odds of complications, and odds of outliers between patients undergoing HRA with and without the use of computer-assisted navigation. Statistical significance was defined as a 95% confidence interval that does not include one. RESULTS:From an initial pool of 223 articles, 13 met inclusion criteria, encompassing 1,287 patients. Analysis revealed a complication rate of 5.29% for the mechanical group vs. 3.35% for the navigation group. Outlier rates were 31.96% for the mechanical group and 8.76% for the computer-assisted group. The average operative time was 110.95 minutes for procedures using navigation compared with 101.16 minutes for traditional HRA. Meta-analysis revealed no statistically significant difference in overall complications. However, the navigation-based HRA cohort demonstrated a significantly lower likelihood of prosthetic placement outliers and a longer operative time. CONCLUSION/CONCLUSIONS:As reported over a decade ago by Liu et al., the use of navigation continues to result in a more accurate prosthetic positioning. Unfortunately, no significant difference was found in clinical outcomes. Future research is needed to demonstrate that the increased accuracy offered by navigation translates into superior postoperative outcomes. Such evidence could advocate for a complete transition from mechanical techniques to computer-assisted navigation as the standard approach for HRA. LEVEL OF EVIDENCE/METHODS:Level III, systematic review of Level II and III studies. See Instructions for Authors for a complete description of levels of evidence.

BACKGROUND:Since its inception, activity level and bone quality have been essential considerations for patients undergoing hip resurfacing arthroplasty (HRA). Moreover, younger patients tend to experience fewer complications, lower revision rates, and better outcomes after any surgery. This study aims to compare the clinical outcomes, complication rates, and survivorship rates between younger and older patients undergoing HRA, providing insights into whether active older patients with appropriate bone quality can still achieve significant benefits from HRA. METHODS:A literature search was conducted using PubMed, Embase, and Scopus databases. Articles were screened by title and abstract, followed by full-text review. A meta-analysis was performed using a random effects model to compare UCLA scores and odds of prosthesis survivorship between younger (<50 years of age) and older (>50 years of age) patients in studies comparing both age groups. Statistical significance was defined as a 95% confidence interval that does not include 1. In addition, the average complication and prosthesis survivorship rates were calculated and compared between younger and older hips using both comparative and noncomparative studies. RESULTS:From an initial pool of 1,286 articles, 31 met inclusion criteria, encompassing 22,691 patients. Analysis revealed a pooled mean age of 33.65 years for the younger cohort and 63 years for the older cohort, and a complication rate of 5.37% in younger compared with 3.83% in older hips. The difference in postoperative UCLA scores was deemed statistically insignificant based on meta-analysis. However, the difference in mean survivorship rates was found to be statistically significant at 86% for younger and 94.9% for older patients through univariate analysis and meta-analysis. CONCLUSION/CONCLUSIONS:There is no significant difference in postoperative outcomes between younger and older patients undergoing HRA. In fact, older patients seem to experience higher prosthesis survivorship rates compared with younger cohorts. Older patients who are active and possess good bone quality can achieve outcomes comparable to their younger counterparts, indicating that HRA may be viable for a broader age range than previously considered. LEVEL OF EVIDENCE/METHODS:Level III, systematic review of Level II, III, and IV studies. See Instructions for Authors for a complete description of levels of evidence.

BACKGROUND:Hip resurfacing arthroplasty (HRA) offers numerous benefits over total hip replacements such as increased preservation of natural bone, improved range of motion, and lower dislocation risks. However, patient selection is crucial, with factors such as bone quality, activity level, and body mass index (BMI) playing significant roles. Obesity in particular poses challenges, potentially increasing mechanical load on the joint, complicating surgical techniques, and affecting both immediate and long-term outcomes. The aim of this systematic review was to evaluate outcomes of HRA in obese vs. nonobese patients to determine if obesity should be considered a contraindication to HRA or if similar treatment approaches can be applied. METHODS:A literature search was conducted using PubMed, Embase, and Scopus databases with specific search terms related to HRA and obesity. Articles were screened by title and abstract, followed by full-text review. Data extraction focused on demographic and study variables such as sex, age, BMI, complication and revision rates, and patient-reported outcomes. A meta-analysis was performed using a random-effects model to compare University of California Los Angeles (UCLA) scores, Harris hip scores, complication rates, and revision rates between obese and nonobese patients, with significance set at p < 0.05. RESULTS:From an initial pool of 39 articles, 4 met inclusion criteria, encompassing 1,385 patients. Analysis revealed a pooled mean age of 50.92 years and a complication rate of 9.83% in obese vs. 4.7% in nonobese patients. Revision rates were 1.15% for obese and 3.70% for nonobese patients. The difference in postoperative UCLA scores, complication rates, and revision rates were deemed not statistically significant. CONCLUSION/CONCLUSIONS:The comparability in patient-reported outcomes, complication rates, and revision rates between obese and nonobese cohorts suggests that although heightened vigilance and tailored approaches may be warranted in obese patients, obesity alone should not preclude patients from undergoing HRA. These findings advocate for a more nuanced approach to patient selection, emphasizing individualized assessment over generalized BMI cutoffs. Future HRA research should focus on long-term follow-up and larger cohort studies to further validate these results. LEVEL OF EVIDENCE/METHODS:Level III, systematic review of Level II and III studies. See Instructions for Authors for a complete description of levels of evidence.

Intramedullary stems are often required in patients undergoing revision total knee arthroplasty (rTKA) to achieve stable fixation. Significant bone loss may require the addition of a metal cone to maximize fixation and osteointegration. The purpose of this study was to investigate clinical outcomes in rTKA using different fixation techniques. We conducted a single-institution retrospective review of all patients who received a tibial and femoral stem during rTKA between August 2011 and July 2021. Patients were separated into three cohorts based on fixation construct: press-fit stem with an offset coupler (OS), fully cemented straight (CS) stem, and press-fit straight (PFS) stem. A subanalysis of patients who received tibial cone augmentation was also conducted. A total of 358 patients who underwent rTKA were included in this study, of which 102 (28.5%) had a minimum 2-year follow-up and 25 (7.0%) had a minimum 5-year follow-up. In the primary analysis, 194 patients were included in the OS cohort, 72 in the CS cohort, and 92 in the PFS cohort. When stem type alone was considered, there was no significant difference in rerevision rate (p = 0.431) between cohorts. Subanalysis of patients who received augmentation with a tibial cone demonstrated that OS implants led to significantly higher rates of rerevision compared with the other two stem types (OS: 18.2% vs. CS: 2.1% vs. PFS: 11.1%; p = 0.037). The findings of the present analysis demonstrate that CS and cones in rTKA may provide more reliable long-term outcomes compared with press-fit stems with OS. LEVEL III EVIDENCE:  Retrospective Cohort Study.

INTRODUCTION/BACKGROUND:Literature examining the risks, benefits, and potential complications of TKA in morbidly obese patients is conflicting. Surgeons with more experience performing TKA on morbidly obese patients may generate superior outcomes. This study sought to assess whether complication rates and implant survivorship in morbidly obese TKA patients varies between high (HV) and low (LV) volume surgeons. METHODS:A retrospective review was performed to include all morbidly obese (BMI ≥ 40) patients that underwent primary TKA between January 2016 and July 2021 at our high-volume center. Demographics and clinical outcomes were collected and compared between surgeons with a higher morbidly obese TKA volume (> 10 annual cases) and surgeons with a lower morbidly obese TKA volume. RESULTS:A total of 964 patients (HV 91 [9.4%], LV 873 [90.6%]) were identified. The HV surgeon and LV surgeons had an average annual volume of 15.3 and 5.2 cases, respectively. The average BMI for the HV and LV cohorts were 44.5 ± 3.7 and 44.0 ± 3.6, respectively (p = 0.160). The HV surgeon had significantly lower operative times (105.7 ± 17.4 vs. 110.7 ± 29.6 min, p = 0.018), and a lower 90-day minor complication rate (0.0% vs. 4.7%, p = 0.035). For patients with at least 2-year follow-up, all-cause revision (3.4% vs. 12.5%, p = 0.149) and revision due to PJI (0.0% vs. 5.8%, 0.193) rates were numerically lower in the HV cohort. Improvements in KOOS, JR and VR-12 scores were similar at 3-month and 1-year follow-up. Freedom from all-cause revision (HV: 96.6% vs. LV: 80.4%, p = 0.175) and revision due to PJI (HV: 100.0% vs. LV: 93.6%, p = 0.190, p = 0.190) at latest follow-up did not statistically differ between groups. CONCLUSION/CONCLUSIONS:The HV surgeon had significantly lower operative time and 90-day minor complication rates and numerically lower all-cause revision and revision due to PJI rates when performing TKA in morbidly obese patients. Surgeon's experience may affect surgical outcomes after TKA in morbidly obese patients. LEVEL OF EVIDENCE/METHODS:III.

BACKGROUND:The impact of morbid obesity (MO) on outcomes following total knee arthroplasty (TKA) when performed by high-volume (HV) surgeons has not been investigated. This study aimed to assess complication rates and implant survivorship in MO patients operated on by HV surgeons. METHODS:Patients undergoing primary, elective TKA between June 2011 and May 2022 with a HV surgeon (top 25% surgeons by the number of primary TKAs per year) were retrospectively reviewed. Patients were stratified by body mass index (BMI) into 3 groups: BMI ≥40 (MO), 30≤ BMI <40 (non-morbidly obese), and BMI <30 (nonobese) and 1:1:1 propensity matched based on baseline characteristics. Of the 12,132 patients evaluated, 1,158 were included in final matched analyses (386 per group). The HV surgeons performed a median of 104 TKAs annually (range, 90-173). RESULTS:The MO patients had significantly longer surgery duration (P = .006) and hospital lengths of stay (P < .001). The 90-day postoperative complications (P = .38) and readmission rates (P = .39) were comparable between groups. Rates of all-cause, septic and aseptic revision were similar between groups at two-year (P = .30, P = .15, and P = .26, respectively) and the latest follow-up (P = .36, P = .52, and P = .38, respectively). Improvement in Knee injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS, JR) scores at 6 months (P = .049) and one year (P = .015) was significantly higher in MO patients. CONCLUSION/CONCLUSIONS:Clinical outcomes and complication rates following TKA by HV surgeons are comparable regardless of obesity status. The MO patients may benefit from referral to experienced surgeons to minimize procedural risks and improve outcomes. LEVEL OF EVIDENCE/METHODS:III.

INTRODUCTION/BACKGROUND:Hip resurfacing arthroplasty (HRA) is a surgical option with positive outcomes at medium-term follow-up for young, active patients with osteoarthritis. However, early failures of HRA often occur due to improper implant placement. The purpose of this study was to assess the utility of computer-assisted navigation in the effort to optimize implant positioning following HRA. MATERIALS AND METHODS/METHODS:A retrospective analysis of 262 consecutive HRAs at a single institution was performed. Radiographic analysis included measurements of cup inclination and anteversion, leg length restoration (LLR), and offset. Cup position was evaluated based on placement within Lewinnek parameters and the surgeon's preferred anteversion (10° to 20°). Chi-squared and unpaired Student's t-test were performed for all categorical and continuous variables, respectively. RESULTS:One hundred fifty-six cases were performed using conventional technique and 106 cases used computernavigation. Computer-assisted HRA (caHRA) had a longer mean surgical time (129 vs. 110 minutes; p < 0.001) but shorter average LOS (1.1 vs. 1.5 days; p < 0.001). Cup position was within the surgeon-preferred target zone in 47% of caHRA versus 22% of conventional HRA (p = 0.0001). Cup position fell within the Lewinnek safe zone in 86% of caHRA versus 60% of conventional HRA (p < 0.001). Global offset was reduced by a mean of 6.4 mm in caHRA versus 8.4 mm (p = 0.036). No differences in rates of complication (p = 0.406), reoperation (p = 1.00), or 90-day readmission (p = 0.568) were observed. CONCLUSION/CONCLUSIONS:Computer-assisted technology in HRA allows for comparable clinical outcomes to conventional technique. Cup position accuracy and precision is improved by computer navigation in HRA.

INTRODUCTION/BACKGROUND:Round or oval implants are used in patellar resurfacing during total knee arthroplasty (TKA). However, whether component geometry affects clinical outcomes is unclear. This study aimed to determine if one implant shape conferred superior outcomes to the other. METHODS:A retrospective review of primary TKA cases performed from 2016 to 2020 was conducted at an urban, tertiary academic center. 400 consecutive, primary TKAs were included in these analyses. Cases were included if a surgeon used the round design then oval design for fifty consecutive cases. Baseline demographic data and radiographic measurements were assessed. Surgical data, reasons for revision, and patient reported outcome measures were analyzed. Independent samples t- and chi-squared tests were used to compare means and proportions. There were no demographic differences between the cohorts. RESULTS:Post-operative patellar tilt was statistically different between the cohorts. Sixteen patients required revision surgery; however, revision rates did not differ between cohorts. Of the nine round, one button was revised for infection. Of the seven oval, one button was revised for infection and one for loosening. Veterans RAND 12 Physical Component Score at three-months postoperatively was higher for the round cohort, but no differences were observed at one-year. CONCLUSION/CONCLUSIONS:While radiographic patellar tilt was significantly different between the cohorts, there was no clinical correlation in outcomes at three-months or one-year postoperatively. Longer-term follow-up studies are needed to evaluate the implications of patellar component design on outcomes and function. Nevertheless, the current study affirms that both designs are clinically equivalent which should be used to guide clinical decision-making.

AIMS/UNASSIGNED:Revision total knee arthroplasty (rTKA) is a technically challenging and costly procedure. It is well-documented that primary TKA (pTKA) have better survivorship than rTKA; however, we were unable to identify any studies explicitly investigating previous rTKA as a risk factor for failure following rTKA. The purpose of this study is to compare the outcomes following rTKA between patients undergoing index rTKA and those who had been previously revised. METHODS/UNASSIGNED:This retrospective, observational study reviewed patients who underwent unilateral, aseptic rTKA at an academic orthopaedic speciality hospital between June 2011 and April 2020 with > one-year of follow-up. Patients were dichotomized based on whether this was their first revision procedure or not. Patient demographics, surgical factors, postoperative outcomes, and re-revision rates were compared between the groups. RESULTS/UNASSIGNED:= -0.102; p = 0.251). CONCLUSION/UNASSIGNED:Multiply revised TKA had worse outcomes, with higher rates of facility discharge, longer operative times, and greater reoperation and re-revision rates compared to index rTKA.