Total Hip Arthroplasty and the Spinopelvic Relationship: What's the Latest!

Although total hip arthroplasty (THA) has proved to be a successful surgical procedure, both prosthetic and bone impingement resulting in dislocation continue to occur. Studies have shown that spine pathology resulting in lumbar stiffness and hip arthritis often coexist. Spinopelvic mobility patterns during postural changes affect three-dimensional acetabular component position, which affects the incidence of prosthetic impingement and THA instability. Several spinopelvic risk factors that may affect THA stability have been identified. Numerous reports recommend performing a preoperative spinopelvic mobility analysis to identify risk factors and adjust acetabular component position accordingly to lessen the risk of impingement. In doing so, acetabular component position is individualized based on spinopelvic mobility patterns. Additionally, functional femoral anteversion, affected by individual femoral rotation patterns during dynamic activities, may contribute to the incidence of impingement. It is important to review the interrelationship between spine and pelvic mobility and how it relates to THA and may reduce the incidence of instability.

Improved Clinical Outcomes With Dynamic, Force-Controlled, Gap-Balancing in Posterior-Stabilized Total Knee Arthroplasty.

BACKGROUND: Optimal soft-tissue management in total knee arthroplasty (TKA) may reduce symptomatic instability. We hypothesized that TKA outcomes using a computer-assisted dynamic ligament balancer that acquires medial and lateral gap sizes throughout the motion arc would show improved Knee Society Scores (KSS) compared to TKAs done with a traditional tensioner at 0 and 90°. We also sought to quantify the degree to which the planned femoral rotation chosen to optimize medio-lateral balance throughout the arc of motion deviated from the femoral rotation needed to achieve a rectangular flexion gap at 90° alone. METHODS: Baseline demographics, clinical outcomes, KSSs, and femoral rotations were compared in 100 consecutive, computer-assisted TKAs done with the balancer (balancer group) to the immediately prior 100 consecutive computer-assisted TKAs done without the balancer (control group). Minimum follow-up was 13 months and all patients had osteoarthritis. Mean knee motion did not differ preoperatively (110.1 ± 13.6° balancer, 110.4 ± 12.5° control, P = .44) or postoperatively (119.1 ± 10.3° balancer, 118.8 ± 10.9° control, P = .42). Tourniquet times did not differ (93.1 ± 13.0 minutes balancer, 90.7 ± 13.0 minutes control, P = .13). Postoperative length of stay differed (40.2 ± 20.9 hours balancer, 49.0 ± 18.3 hours control, P = .0009). There were 14 readmissions (7 balancer, 7 control), 11 adverse events (4 balancer, 7 control), and 3 manipulations (1 balancer, 2 control). The cohorts were compared using Student's t-tests, Shapiro-Wilk normalities, Wilcoxon rank-sums, and multivariable logistic regression analyses. RESULTS: Postoperative KSS improvements were higher in the balancer group (P < .0001). In multivariable regression analyses, the balancer group experienced 7 ± 2 point improvement in KSS Knee scores (P < .0001) and 4 ± 2 point improvement in KSS Function scores (P = .040) compared to the control group. CONCLUSIONS: The statistically and clinically significant improvements in postoperative KSS demonstrated in the balancer cohort are likely driven by improved stability throughout the motion arc. Further study is warranted to evaluate replicability by non-design surgeons.

Is American Joint Replacement Registry Data Consistent With International Survivorship in Hip and Knee Arthroplasty? A Comparative Analysis.

BACKGROUND: In collaboration with the Orthopedic Data Evaluation Panel (ODEP), the American Joint Replacement Registry (AJRR) investigated the consistency of hip and knee arthroplasty survivorship results compared to the UK National Joint Registry (NJR). METHODS: A total of three primary knee devices and three primary hip devices were selected by AJRR and ODEP with known variation in performance. Implant manufacturers independently produced Kaplan Meier survivorship based on NJR data and submitted to ODEP for comparison. The AJRR mirrored the methodology, and results from both sources were stratified into three cohorts (all-age, < 65, and ≥ 65 years). RESULTS: There were 42,671 AJRR and 60,439 NJR primary knee cases and 70,169 AJRR and 422,657 NJR primary total hip arthroplasty cases. For TKA, performance between the AJRR and NJR were consistent, showing similar trends for comparatively high and low performing devices. Both PS and CR devices showed statistical agreement in survivorship for all 3 cohorts. Unicompartmental comparison also showed statistical agreement for the Medicare cohort. The all-age and < 65-year-old cohorts showed similar trends and reached statistical agreement through 7 and 6 years. For total hip arthroplasty, performance between the AJRR and NJR were consistent, showing similar trends for comparatively high and low performing devices; 0.18% average difference in survivorship at final follow-up (8 years). One femoral device did not reach statistical agreement but showed only 0.61% difference in survivorship. The remaining acetabular and femoral devices reached statistical agreement in all-ages and through 7 and 8 years in the ≥ 65-year-old cohort. CONCLUSIONS: AJRR and NJR performance trends and survivorship were similar across hip and knee arthroplasty with greatest consistency in the all-age and ≥ 65 cohorts. This focused comparison of survivorship showed encouraging results for reliability of patient outcomes in AJRR compared to the world's largest joint arthroplasty registry which has strong implications for global improvement in patient safety.

The Influence of an Unexpected Symbolic Gift on Postoperative Arthroplasty Patients' Press Ganey Scores.

BACKGROUND: Hospitals use Press Ganey surveys to evaluate patient satisfaction. The goal of our study was to evaluate whether surgeon-driven gifting to patients postoperatively affects Press Ganey Survey responses. METHODS: There were 1,468 patients undergoing arthroplasty at our institution who were randomized to receive a thank-you gift, a small bouquet of flowers, and a note from their provider after surgery, or nothing for completing their preoperative arthroplasty registry questionnaire. Press Ganey surveys were sent to patients who received and did not receive flowers immediately after their hospital stay and after the patients' first postoperative visit. Scores were reported as the mean score and the fraction of responses with a top-box rating. One-sided student t-tests and Fisher's exact tests were used to assess statistical significance. RESULTS: Hospital Discharge: Patients who received flowers had higher Press Ganey survey scores than patients who did not receive flowers. For example, for "physician's concerns for questions," they had higher scores (mean difference: 3.7 ± 1.6 points, P = .012) and a 9% higher top-box rating (P = .032). For "staff attitude toward visitors," they also had higher scores (mean difference: 2.8 ± 1.3 points, P = .019) and a 7% higher top-box rating (P = .049). First Follow-up: Patients who received flowers had a higher top-box rating for "concern provider showed for questions" and "amount of time provider spent with you" by 6% (P = .046) and 11% (P = .009), respectively. They also had higher scores for "information provider gave about medications" (mean difference: 4.0 ± 1.6 points, P = .009) and 11% higher top-box rating (P = .006). CONCLUSIONS: Press Ganey Surveys were higher in orthopaedic patients who received bouquets of flowers from their arthroplasty surgeons compared to patients who did not. At follow-up, improved Press Ganey scores persisted if the patient received flowers. The gift of flowers generates patient loyalty to their surgeon.

One-Year Postoperative Patient-Reported Outcome Measures Are Associated With Three-Year to Five-Year Postoperative Satisfaction in Total Knee Arthroplasty.

BACKGROUND: Over the past couple of decades, the definition of success after total knee arthroplasty (TKA) has shifted away from clinician-rated metrics and toward the patient's subjective experience. Therefore, understanding the aspects of patient recovery that drive 3-year to 5-year satisfaction after TKA is crucial. The aims of this study were to (1) determine the 1-year postoperative factors, specifically patient-reported outcome measures (PROMs) that were associated with 3-year and 5-year postoperative satisfaction and (2) understand the factors that drive those who are not satisfied at 1 year postoperatively to become satisfied later in the postoperative course. METHODS: This was a retrospective study of 402 TKA patients who were gathered prospectively and presented for their 1-year follow-up. Demographics were collected preoperatively and patient-reported outcomes were collected at 1, 3, and 5 years postoperatively. Logistic regressions were used to identify the factors at 1 year that were associated with 3-year and 5-year satisfaction. RESULTS: Associations between 1-year PROMs with 3-year satisfaction were observed. Longer term satisfaction at 5 years was more closely associated with EuroQol 5 Dimension Mobility, Activity Score, and Numerical Rating Scale Satisfaction. Of those who were not satisfied at 1 year, EuroQol 5 Dimension Mobility, Knee Disability Osteoarthritis Outcome Score Function in Sport and Recreation, and Satisfaction were associated with becoming satisfied at 3 years. CONCLUSION: The 1-year PROMs were found to be associated with satisfaction at 3 to 5 years after TKA. Importantly, many of the PROMs that were associated with 3-year to 5-year satisfaction, especially in those who were not originally satisfied at 1 year, were focused on mobility and activity level.

Objective Activity Parameters Track Patient-specific Physical Recovery Trajectories After Surgery and Link With Individual Preoperative Immune States.

OBJECTIVE: The longitudinal assessment of physical function with high temporal resolution at a scalable and objective level in patients recovering from surgery is highly desirable to understand the biological and clinical factors that drive the clinical outcome. However, physical recovery from surgery itself remains poorly defined and the utility of wearable technologies to study recovery after surgery has not been established. BACKGROUND: Prolonged postoperative recovery is often associated with long-lasting impairment of physical, mental, and social functions. Although phenotypical and clinical patient characteristics account for some variation of individual recovery trajectories, biological differences likely play a major role. Specifically, patient-specific immune states have been linked to prolonged physical impairment after surgery. However, current methods of quantifying physical recovery lack patient specificity and objectivity. METHODS: Here, a combined high-fidelity accelerometry and state-of-the-art deep immune profiling approach was studied in patients undergoing major joint replacement surgery. The aim was to determine whether objective physical parameters derived from accelerometry data can accurately track patient-specific physical recovery profiles (suggestive of a 'clock of postoperative recovery'), compare the performance of derived parameters with benchmark metrics including step count, and link individual recovery profiles with patients' preoperative immune state. RESULTS: The results of our models indicate that patient-specific temporal patterns of physical function can be derived with a precision superior to benchmark metrics. Notably, 6 distinct domains of physical function and sleep are identified to represent the objective temporal patterns: ''activity capacity'' and ''moderate and overall activity (declined immediately after surgery); ''sleep disruption and sedentary activity (increased after surgery); ''overall sleep'', ''sleep onset'', and ''light activity'' (no clear changes were observed after surgery). These patterns can be linked to individual patients preopera-tive immune state using cross-validated canonical-correlation analysis. Importantly, the pSTAT3 signal activity in monocytic myeloid-derived suppressor cells predicted a slower recovery. CONCLUSIONS: Accelerometry-based recovery trajectories are scalable and objective outcomes to study patient-specific factors that drive physical recovery.

Risk Should Not Be a "Four-Letter Word" in Healthcare. Risk and the Future of Musculoskeletal Care.

Orthopaedics has seen a rapid transition to value-based care. As we transition away from fee-for-service models, healthcare systems, groups, and surgeons are being asked to take on an increasing amount of risk. While on the surface risk may have a negative connotation, managing risk allows surgeons to maintain autonomy while taking on value-based care to the next level. The purpose of this paper, the first in a series of 2, is to walk through the impact that value-based care has had on musculoskeletal surgeons, to understand the continued movement healthcare is making into risk sharing models, and to introduce the concept of surgeon specialist-led care.

Concentrated Economic Disadvantage Predicts Resource Utilization After Total Knee Arthroplasty.

BACKGROUND: The Index of Concentration at the Extremes (ICE), a measure of geographic socioeconomic polarization, predicts several health outcomes but has not been evaluated concerning total knee arthroplasty (TKA). This study evaluates ICE as a predictor of post-TKA resource utilization. METHODS: Using the Healthcare Cost and Utilization Project's New York State database from 2016 to 2017, we retrospectively evaluated 57,426 patients ≥50 years undergoing primary TKA. The ICE values for extreme concentrations of income and race were calculated using United States Census Bureau data with the formula ICEi = (Pi-Di)/Ti where Pi, Di, and Ti are the number of households in the most privileged extreme, disadvantaged extreme, and total population in zip code i, respectively. Extremes of privilege and disadvantage were defined as ≥$150,000 versus <$25,000 for income and non-Hispanic White versus non-Hispanic Black for race. Association of ICE values, demographics, and comorbidities with 90-day readmission and 90-day emergency department (ED) visits was examined using multivariable analysis. RESULTS: Overall 90-day readmission and ED visit rates were 12.8% and 9.4%, respectively. On multivariable analysis, the lowest ICEIncome quintile (concentrated poverty) predicted 90-day readmission (odds ratio 1.17, 95% confidence interval 1.05 to 1.30, P = .005) and 90-day ED visit (odds ratio 1.22, 95% confidence interval 1.08 to 1.38, P = .001). The ICERace was not predictive of either outcome. CONCLUSION: Patients in communities with the lowest ICEIncome values use more inpatient and ED resources after primary TKA. Incorporating ICEIncome into risk-adjusted payment models may help align incentives for equitable care.

High Prevalence of Spinopelvic Risk Factors in Patients With Post-Operative Hip Dislocations.

BACKGROUND: Excessive standing posterior pelvic tilt (PT), lumbar spine stiffness, low pelvic incidence (PI), and severe sagittal spinal deformity (SSD) have been linked to increased dislocation rates. We aimed to determine the prevalence of these 4 parameters in a cohort of unstable total hip arthroplasty (THA) patients and compare these to a large representative control population of primary THA patients. METHODS: Forty-eight patients with instability following primary THA were compared to a control cohort of 9414 THA patients. Lateral X-rays in standing and flexed-seated positions were used to assess PT and lumbar lordosis (LL). Computed tomography scans were used to measure PI and acetabular cup orientation. Thresholds for "at risk" spinopelvic parameters were standing posterior PT ≤ -15°, lumbar flexion (LLstand-LLseated) ≤ 20°, PI ≤ 41°, PI ≥ 70°, and SSD (PI-LLstand mismatch ≥ 20°). RESULTS: There were significant differences in mean spinopelvic parameters between the dislocating and control cohorts (P < .001). There were no differences in mean PI (58° versus 56°, respectively, P = .29) or prevalence of high and low PI between groups. 67% of the dislocating patients had one or more significant risk factors, compared to only 11% of the control. A total of 71% of the dislocating patients had cup orientations within the traditional safe zone. CONCLUSION: Excessive standing posterior PT, low lumbar flexion, and a severe SSD are more prevalent in unstable THAs. Pre-op screening for these parameters combined with appropriate planning and implant selection may help identify at risk patients and reduce the prevalence of dislocation.

The Impact of Exchanging Cerclage Fixation after Extended Trochanteric Osteotomy in Revision Total Hip Arthroplasty for Periprosthetic Joint Infection.

BACKGROUND: An extended trochanteric osteotomy (ETO) is a powerful tool for femoral component revision. There is limited evidence that directly supports its use in the setting of a periprosthetic joint infection (PJI). Cerclage fixation raises the theoretical concern for persistent infection. METHODS: Our institutional database included 76 ETOs for revision hip arthroplasty between January 1, 2008 and December 31, 2019. The cohort was divided based on indication for femoral component revision: PJI versus aseptic revision. The PJI group was subdivided based on second-stage exchange versus retention of initial cerclage fixation. Operative time, estimated blood loss, complications, and rate of repeat revision surgery were evaluated. RESULTS: Forty-nine patients (64%) underwent revision for PJI and 27 patients (36%) underwent aseptic revision. There was no significant difference in operative times (P = .082), postoperative complications (P = .258), or rate of repeat revision surgery (P = .322) between groups. Of the 49 patients in the PJI group, 40 (82%) retained cerclage fixation while 9 (18%) had cerclage exchange. Cerclage exchange did not significantly impact operative time (P = .758), blood loss (P = .498), rate of repeat revision surgery (P = .302), or postoperative complications (P = .253) including infection (P = .639). CONCLUSION: An ETO remains a powerful tool for femoral component removal, even in the presence of a PJI. A multi-institutional investigation would be required to validate observed trends toward better infection control with cerclage exchange. Cerclage exchange did not appear to increase operative time, blood loss, or postoperative complication rates.

Revision Hip Arthroplasty Using a Modular, Cementless Femoral Stem: Long-Term Follow-Up.

BACKGROUND: As the number of primary total hip arthroplasty (THA) cases increase, so does the demand for revision operations. However, long-term follow-up data for revision THA is lacking. METHODS: A retrospective review was completed of patients who underwent revision THA at a single institution between January 2002 and October 2007 using a cementless modular stem. Patient demographic, clinical, and radiographic data was collected. Preoperative and postoperative patient-reported outcome scores were compared at a minimum of fourteen-year follow-up. RESULTS: Eighty-four patients (89 hips) with a median age of 69 years (range, 28 to 88) at operation were included. Indications for revision included aseptic loosening (84.2%), infection (12.4%), and periprosthetic fracture (3.4%). Twenty-two hips sustained at least 1 complication: intraoperative fracture (7.9%), dislocation (6.7%), prosthetic joint infection (4.5%), deep venous thrombosis (3.4%), and late periprosthetic fracture (2.2%). There were no modular junction complications. Eight patients underwent reoperations; only three involved the stem. Thirty-eight patients (45%) were deceased prior to final follow-up without known reoperations. Twenty-seven patients (32%) were lost to follow-up. Twenty-one patients (23%) were alive at minimum fourteen-year follow-up. Complete patient-reported outcomes were available for nineteen patients (range, 14 to 18.5 years of follow-up). Significant improvement was seen in UCLA activity, VR-12 physical, hip disability and osteoarthritis outcome score, joint replacement., and Harris Hip score pain and function scores. CONCLUSION: Challenges of long-term follow-up include patient migration, an unwillingness to travel for re-examination, medical comorbidities, advanced age, and death. The cementless modular revision stem demonstrated long-term clinical success and remains a safe and reliable option for complex revision operations.

Isolated Versus Full Component Revision in Total Knee Arthroplasty for Aseptic Loosening.

BACKGROUND: Revision of both femoral and tibial components of a total knee arthroplasty (TKA) for aseptic loosening has favorable outcomes. Revision of only one loose component with retention of others has shorter operative time and lower cost; however, implant survivorship and clinical outcomes of these different operations are unclear. METHODS: Between January 2009 and December 2019, a consecutive cohort of revision TKA was reviewed. Univariate and multivariable analyses were used to study correlations among factors and surgical related complications, time to prosthesis failure, and functional outcomes (University of California Los Angeles, Knee Society functional, knee osteoarthritis and outcome score for joint replacement, Veterans RAND 12 (VR-12) physical, and VR-12 mental). RESULTS: A total of 238 patients underwent revision TKA for aseptic loosening. The mean follow-up time was 61 months (range 25 to 152). Ten of the 105 patients (9.5%) who underwent full revision (both femoral and tibial components) and 18 of the 133 (13.5%) who underwent isolated revision had subsequent prosthesis failure [Hazard ratio (HR) 0.67, P = .343]. The factor analysis of type of revision (full or isolated revision) did not demonstrate a significant difference between groups in terms of complications, implant failures, and times to failure. Metallosis was related to early time to failure [Hazard ratio 10.11, P < .001] and iliotibial band release was associated with more complications (Odds ratio 9.87, P = .027). Preoperative symptoms of instability were associated with the worst improvement in University of California Los Angeles score. Higher American Society of Anesthesiologists status and higher Charlson Comorbidity Index were related with worse VR-12 physical (-30.5, P = .008) and knee osteoarthritis and outcome score for joint replacement (-4.2, P = .050) scores, respectively. CONCLUSION: Isolated and full component revision TKA for aseptic loosening does not differ with respect to prosthesis failures, complications, and clinical results at 5 years. Poor American Society of Anesthesiologists status, increased comorbidities, instability, and a severe bone defect are related to worse functional improvement. LEVEL OF EVIDENCE: III, cohort with control.

Complications, Implant Survivorships, and Functional Outcomes of Conversion Total Knee Arthroplasty With Prior Hardware.

BACKGROUND: End-stage knee osteoarthritis with retained periarticular hardware is a frequent scenario. Conversion total knee arthroplasty (TKA) leads to excellent outcomes, but poses unique challenges. The evidence supporting retention versus removal of hardware during TKA is controversial. METHODS: Patients who underwent TKA with prior hardware between January 2009 and December 2019 were identified. A total of 148 patients underwent TKA with prior hardware. The mean follow-up was 60 months (range, 24-223). Univariate and multivariable analyses were used to study correlations among factors and surgical-related complications, prosthesis failures, and functional outcomes. RESULTS: The complication rate was 28 of 148 (18.9%). The use of a quadriceps snips in addition to a medial parapatellar arthrotomy was associated with a higher complication (odds ratio: 20.7, P < .05), implant failures (odds ratio: 13.9, P < .05), and lower the Veterans Rand 12 Mental Score (VR-12 MS) (-14.8, P < .05). Hardware removal versus retention and use of single versus multiple incisions were not associated with complications or prosthesis failures. Removal of all hardware was associated with significantly higher (+7.3, P < .05) VR-12 MS compared to retention of all hardware. CONCLUSIONS: TKA with prior hardware was associated with more complications, implant failures, and lower VR-12 MS when a more constrained construct or quadriceps snip was performed. This probably reflects the level of difficulty of the procedure rather than the surgical approach used. Hardware removal or retention was not associated with complications or implant failures; however, removal rather than retention of all prior hardware is associated with increased general health outcomes. LEVEL OF EVIDENCE: IV, cohort without control.

Gap Balancing Throughout the Arc of Motion With Navigated TKA and a Novel Force-Controlled Distractor: A Review of the First 273 Cases.

BACKGROUND: This study evaluated the ability to achieve the targeted soft-tissue balance in terms of medio-lateral (ML) laxity and gap values when using a computer-assisted orthopedic surgery (CAOS) system featuring an intra-articular force-controlled distractor and assessed learning curves associated with the adoption of this technology. METHODS: The first 273 cases using this technology were reported without exclusions comparing 1) final ML laxity and 2) final average gap to their predefined targets. For both parameters, the signed and unsigned differentials were reported. The linear mixed model was used to evaluate laxity curve differences between surgeons. A cumulative sum control chart (CUSUM) was applied to assess surgeon learning curves regarding surgical time. RESULTS: Both the average signed ML laxity and gap differentials were neutral throughout the full arc of motion. Both the average unsigned ML laxity and gap differentials were linear. Signature of ML laxity and gap differential curves tended to be surgeon-specific. The CUSUM analyses of surgical times demonstrated either a short learning curve or the absence of a discernible learning pattern for surgeons. CONCLUSION: Data from all users involved with the pilot release of the balancing device were considered to capture variability in familiarity with the technique and learning curve cases were included. A high ability to achieve targeted gap balance throughout the arc of motion using the proposed method was observed.

An External Acetabular Alignment Guide Decreases Positional Variance.

INTRODUCTION: Certain patient and operative factors limit accurate estimation of acetabular component positioning during total hip arthroplasty (THA). This study aimed to determine whether an intraoperative external alignment guide decreases variance in acetabular component positioning. MATERIALS AND METHODS: Adult patients who underwent primary THA from 2014-2018 were reviewed. Exclusion criteria were navigation, robot-assisted surgery, and inflammatory, post-traumatic, or avascular arthritis. One surgeon used an external guide while the second surgeon resected osteophytes and utilized available anatomical landmarks for positioning. Anteversion and inclination, variance, "safe zone" positioning, operative time, and hip instability were assessed. Multivariable regression models were used to examine effects on primary and secondary outcomes. RESULTS: 409 patients were included, of which 182 underwent component placement with landmarks only. Patients undergoing component placement with landmarks only were younger (p=0.002) and more often smokers (p=0.016). After multivariable risk adjustment, use of the external alignment guide was independently associated with 2.7° higher anteversion (CI: 1.6° to 3.8°) and smaller anteversion variance (-0.3, CI: -0.6 to 0.1) compared to landmarks only. It was independently associated with 3.2° higher inclination (CI: 2.0° to 4.4°), but there was no difference in inclination variance (-0.1, CI: -0.3 to 0.2). The external alignment guide was independently associated with a 14-minute shorter operative time (CI: 9.6 to 18.7) and smaller operative time variance (-0.9, CI: -1.2 to 0.6). DISCUSSION: Use of anatomical landmarks alone was associated with increased likelihood of safe zone positioning but lower precision and longer operative time. While this study was limited by lack of randomization and its retrospective nature, an acetabular positioner may be preferable to palpable or visible anatomy alone for acetabular component placement.

Outcome of the Wagner Cone femoral component for difficult anatomical conditions during total hip arthroplasty.

PURPOSE: Total hip arthroplasty (THA) in patients with small or unusual proximal femoral anatomy is challenging due to sizing issues, control of version, and implant fixation. The Wagner Cone is a monoblock, fluted, tapered stem with successful outcomes for these patients; however, there is limited information on subsidence, a common finding with cementless stems. METHODS: We retrospectively reviewed our cases using the modified Wagner Cone (Zimmer, Warsaw, IN) implanted over a 13-year period (2006-2019) in patients with small or abnormal proximal femoral anatomy. We performed 144 primary THAs in 114 patients using this prosthesis. Mean follow-up was 4.5 ± 3.4 years (range, 1-13 years). Common reasons for implantation were hip dysplasia (52%) and osteoarthritis in patients with small femoral proportions (22%). Analysis of outcomes included assessment of stem subsidence and stability. RESULTS: Survival was 98.6% in aseptic cases; revision-free survival was 97.9%. Femoral subsidence occurred in 84 cases (58%). No subsidence progressed after 3 months. Of those that subsided, the mean distance was 2.8 ± 2.0 mm. There was less subsidence in stems that stabilized prior to six weeks (2.2 ± 1.4 mm) compared to those that continued until 12 weeks (3.9 ± 1.6, p = 0.02). Harris Hip, UCLA, and WOMAC scores significantly improved from pre-operative evaluation (p < 0.001*, p < 0.003*, p ≪ 0.001*); there was no difference in outcome between patients with and without subsidence (p = 0.430, p = 0.228, p = 0.147). CONCLUSION: The modified Wagner Cone demonstrates excellent clinical outcomes in patients with challenging proximal femoral anatomy. Subsidence is minor, stops by 3 months, and does not compromise clinical outcome.

Staging Bilateral Total Knee Arthroplasties Reduces Alignment Outliers.

BACKGROUND: Patients frequently present with bilateral symptomatic knee osteoarthritis and request simultaneous total knee arthroplasties (TKAs). Technical differences between simultaneous and staged TKAs could affect clinical and radiographic outcomes. We hypothesized that staged TKAs would have fewer mechanical alignment outliers than simultaneous TKAs. METHODS: We reviewed 87 simultaneous and 72 staged TKAs with at least 2 years of follow-up. Radiographic assessment was done using standing long leg and lateral radiographs of the knee. Coronal and sagittal measurements were performed by 4 blinded observers on 2 separate occasions with an intraobserver agreement of 0.95 and interobserver of 0.92. RESULTS: The first simultaneous knee had no difference in the probability of establishing the mechanical axis outside 3° of neutral (45%) compared to the first staged knee (54%, P = .337). However, the second simultaneous knee (49%) was more likely to establish the axis outside mechanical neutral compared to the second staged knee (28%; odds ratio 2.54, confidence interval 1.31-4.94, P = .006). There was an increased risk of deep venous thrombosis with staged TKA (odds ratio 2.96, confidence interval 1.28-6.84, P = .011), but other perioperative complication rates were not significantly different. There were no clinically significant differences in range of motion or Knee Society Score. CONCLUSION: There is a significantly increased risk of establishing the second knee outside mechanical neutral during a simultaneous TKA compared to staged bilateral TKAs, possibly related to a number of surgeon-related and system-related factors. The impact on clinical outcomes and radiographic loosening may become significant in long-term follow-up.

Caring for Diverse and High-Risk Patients: Surgeon, Health System, and Patient Integration.

Access and outcome disparities exist in hip and knee arthroplasty care. These disparities are associated with race, ethnicity, and social determinants of health such as income, housing, transportation, education, language, and health literacy. Additionally, medical comorbidities affecting postoperative outcomes are more prevalent in underresourced communities, which are more commonly communities of color. Navigating racial and ethnic differences in treating our patients undergoing hip and knee arthroplasty is necessary to reduce inequitable care. It is important to recognize our implicit biases and lessen their influence on our healthcare decision-making. Social determinants of health need to be addressed on a large scale as the current inequitable system disproportionally impacts communities of color. Patients with lower health literacy have a higher risk of postoperative complications and poor outcomes after hip and knee replacement. Low health literacy can be addressed by improving communication, reducing barriers to care, and supporting patients in their efforts to improve their own health. High-risk patients require more financial, physical, and mental resources to care for them, and hospitals, surgeons, and health insurance companies are often disincentivized to do so. By advocating for alternative payment models that adjust for the increased risk and take into account the increased perioperative work needed to care for these patients, surgeons can help reduce inequities in access to care. We have a responsibility to our patients to recognize and address social determinants of health, improve the diversity of our workforce, and advocate for improved access to care to decrease inequity and outcomes disparities in our field.

Imageless Computer Navigation Reduces 5-Year All-Cause Revision Rates After Primary Total Knee Arthroplasty.

BACKGROUND: The use of surgical navigation has been shown to reduce revision rates after total knee arthroplasty (TKA) in patients <65 years of age. It is unknown if this benefit extends to older patients. We hypothesized that the use of surgical navigation would reduce rates of all-cause revision in patients of all ages. METHODS: In this cohort study, we queried the Truven MarketScan all-payer database to identify patients who underwent TKA from 2007 to 2015. Current Procedural Terminology codes were used to create 2 groups based on whether intraoperative navigation was used. Demographics, comorbidities, complications, and revision rates were determined. International Classification of Diseases codes were used to determine reasons for revision. RESULTS: The conventional TKA cohort included 312,173 patients. The navigation cohort included 20,881 patients. There were not any clinically significant differences in demographics between the cohorts. All-cause revision rates were lower in the navigation cohort at 1 year (0.4% vs 0.5%, P = .04), 2 years (0.7% vs 0.9%, P = .003), and 5 years (0.9% vs 1.3%, P < .001) of follow-up. Revisions for mechanical loosening were more common in the conventional cohort (30.8% vs 21.9%, P = .009). Rates of revision for other causes, including infection, did not differ between groups, with the numbers available. CONCLUSION: The use of surgical navigation yielded a 30.7% reduction in the all-cause revision rate at 5-year follow-up compared to conventional TKA. This benefit increased as follow-up duration increased. Increased usage of this inexpensive technology, from the current 6.3% in this US cohort, may reduce healthcare costs. LEVEL OF EVIDENCE: III.

The Effect of Femoral Fixation on Revision and Mortality Following Elective Total Hip Arthroplasty in Patients Over the Age of 65 years. An Analysis of the American Joint Replacement Registry.

BACKGROUND: With the overwhelming use of cementless femoral fixation for primary total hip arthroplasty in the United States, the associations of stem fixation on the risk of revision and mortality are poorly understood. We evaluated the relationship between femoral fixation and risk of revision and mortality in patients included in the American Joint Replacement Registry. METHODS: Elective, primary, unilateral total hip arthroplasties in the American Joint Replacement Registry, in patients over the age of 65 years were considered. In total, 9,612 patients with a cemented stem were exact matched 1:1 with patients who received a cementless stem based on age, gender, and the Charlson Comorbidity Index. Outcomes compared between the groups included need and reason for revision at 90 days and 1 year; in-hospital, 90-day, and 1-year mortality; and mortality after early revision. Covariates were used in linear regression analyses. RESULTS: Cemented fixation was associated with a 37% reduction in the risk of 90-day revision, and a reduction in the risk of revision for periprosthetic fracture of 87% at 90 days and 81% at 1 year. Cemented fixation was associated with increased 90-day and 1-year mortality (odds ratio [OR] 3.15, confidence interval [CI] 2.24-4.43 and OR 2.36, CI 1.86-3.01, respectively). Patients who underwent subsequent revision surgery within the first year exhibited the highest mortality risk (OR 3.23, CI 1.05-9.97). CONCLUSION: In this representative sample of the United States, 90-day revision for any reason and for periprosthetic fracture was significantly reduced in patients with a cemented stem. This benefit must be weighed against the association with increased mortality and with the high risk of mortality associated with early revision, which was more prevalent with cementless fixation.