Role of femoral head material on readmission and mortality rates following elective primary total hip arthroplasty in Medicare patients.

INTRODUCTION: The role of different femoral head materials for total hip arthroplasty (THA) has been widely studied in the context of wear properties and corrosion. Cobalt chrome (CoCr) femoral heads are commonly used as a standard of comparison to other materials such as ceramic and oxidized zirconium (OxZi). This study aims to evaluate the impact of femoral head material on clinical outcomes in elective primary THA patients. METHODS: Retrospective analysis of THA patients within the Medicare claims database between October 2017 and September 2020 using diagnosis-related group codes was conducted. Information collected included sex, age, Charlson Comorbidity Index, and femoral head type. Patients with CoCr femoral heads were compared against patients with either OxZi or ceramic femoral heads using 1:1 propensity score matching. Z-testing and Chi-square analysis were used to determine between-group significance. RESULTS: In total, 112,960 elective THA patients were included, with 56,480 in OxZi or ceramic and 56,480 in CoCr. Readmission rates were lower in patients that received OxZi or ceramic femoral heads at 30-day (p < 0.0001), 60-day (p < 0.0001), and 90-day postoperatively (p < 0.0001) compared to CoCr. Mortality rates were also lower in patients that received OxZi or ceramic femoral heads at 30-day (p = 0.004), 60-day (p = 0.018), and 90-day postoperatively (p = 0.009) compared to CoCr. CONCLUSION: CoCr femoral heads had higher rates of readmissions and mortality compared to OxZi or ceramic. Further analysis of bearing surface combinations and sub-group analyses to determine significance between-group differences is needed. LEVEL III EVIDENCE: Retrospective analysis.

The Effect of Surgeon and Hospital Volume on Total Knee Arthroplasty Patient-reported Outcome Measures: An American Joint Replacement Registry Study.

BACKGROUND: The lower morbidity and mortality rate associated with increased surgeon and hospital volume may also correlate with improved patient-reported outcome measures. The goal of this study was to determine the relationship between surgeon and hospital volume and patient-reported outcome measures after total knee arthroplasty (TKA) using American Joint Replacement Registry data. METHODS: Using American Joint Replacement Registry data from 2012 to 2020, 8,193 primary, elective TKAs with both preoperative and 1-year postoperative The Knee Injury and Osteoarthritis Outcome Score, Joint Replacement (KOOS-JR) scores were analyzed. This study was powered to detect the minimally clinical important difference (MCID). The main exposure variables were median annual surgeon and hospital volume. Tertiles were formed based on the median annual number of TKAs performed: low-volume surgeons (1 to 52), medium-volume (53 to 114), and high-volume (≥115); low-volume hospitals (1 to 283), medium-volume (284 to 602), and high-volume (≥603). The mean preoperative and 1-year postoperative KOOS-JR were compared. Multivariable logistic regression models were used to determine the effect of surgeon and hospital volume and demographics on achieving the MCID for KOOS-JR. RESULTS: The mean preoperative and 1-year postoperative KOOS-JR score for low-volume surgeons was 47.78 ± 13.50 and 77.75 ± 16.65, respectively, and 47.32 ± 13.73 and 76.86 ± 16.38 for low-volume hospitals. The mean preoperative and 1-year postoperative KOOS-JR score for medium-volume surgeons was 47.20 ± 13.46 and 76.70 ± 16.98, and 48.93 ± 12.50 and 77.15 ± 16.36 for medium-volume hospitals. The mean preoperative and 1-year postoperative KOOS-JR scores for high-volume surgeons were 49.08 ± 13.04 and 78.23 ± 16.72, and 48.11 ± 13.47 and 78.23 ± 17.22 for high-volume hospitals. No notable difference was observed in reaching MCID for KOOS-JR after adjustment for potential confounders. CONCLUSION: An increased number of TKA cases performed by a given surgeon or at a given hospital did not have an effect on achieving MCID for KOOS-JR outcomes.

Does antibiotic bone cement reduce infection rates in primary total knee arthroplasty?

INTRODUCTION: Infection after total knee arthroplasty (TKA) impacts the patient, surgeon, and healthcare system significantly. Surgeons routinely use antibiotic-loaded bone cement (ALBC) in attempts to mitigate infection; however, little evidence supports the efficacy of ALBC in reducing infection rates compared to non-antibiotic-loaded bone cement (non-ALBC) in primary TKA. Our study compares infection rates of patients undergoing TKA with ALBC to those with non-ALBC to assess its efficacy in primary TKA. METHODS: A retrospective review of all primary, elective, cemented TKA patients over the age of 18 between 2011 and 2020 was conducted at an orthopedic specialty hospital. Patients were stratified into two cohorts based on cement type: ALBC (loaded with gentamicin or tobramycin) or non-ALBC. Baseline characteristics and infection rates determined by MSIS criteria were collected. Multilinear and multivariate logistic regressions were performed to limit significant differences in demographics. Independent samples t test and chi-squared test were used to compare means and proportions, respectively, between the two cohorts. RESULTS: In total, 9366 patients were included in this study, 7980 (85.2%) of whom received non-ALBC and 1386 (14.8%) of whom received ALBC. There were significant differences in five of the six demographic variables analyzed; patients with higher Body Mass Index (33.40 ± 6.27 vs. 32.09 ± 6.21; kg/m2) and Charlson Comorbidity Index values (4.51 ± 2.15 vs. 4.04 ± 1.92) were more likely to receive ALBC. The infection rate in the non-ALBC was 0.8% (63/7,980), while the rate in the ALBC was 0.5% (7/1,386). After adjusting for confounders, the difference in rates was not significant between the two groups (OR [95% CI]: 1.53 [0.69-3.38], p = 0.298). Furthermore, a sub-analysis comparing the infection rates within various demographic categories also showed no significant differences between the two groups. CONCLUSION: Compared to non-ALBC, the overall infection rate in primary TKA was slightly lower when using ALBC; however, the difference was not statistically significant. When stratifying by comorbidity, use of ALBC still showed no statistical significance in reducing the risk of periprosthetic joint infection. Therefore, the advantage of antibiotics in bone cement to prevent infection in primary TKA is not yet elucidated. Further prospective, multicenter studies regarding the clinical benefits of antibiotic use in bone cement for primary TKA are warranted.

Is It Necessary to Obtain Lateral Pelvic Radiographs in Flexed Seated Position for Preoperative Total Hip Arthroplasty Planning?

Background: Many of the current total hip arthroplasty (THA) planning tools only consider sagittal pelvic tilt in the standing and relaxed sitting positions. Considering that the risk of postoperative dislocation is higher when bending forward or in sit-to-stand move, sagittal pelvic tilt in the flexed seated position may be more relevant for preoperative planning. We hypothesized that there was a significant difference in sagittal pelvic tilt between the relaxed sitting and flexed seated positions as measured by the sacral slope in preoperative and postoperative full-body radiographs. Methods: This was a multicenter retrospective analysis of the preoperative and postoperative simultaneous biplanar full-body radiographs of 93 primary THA patients in standing, relaxed sitting, and flexed seated positions. The sagittal pelvic tilt was measured using the sacral slope relative to the horizontal line. Results: The mean difference between the preoperative sacral slope in the relaxed sitting position and the flexed seated position was 11.3° (-13° to 43°) (P < .0001). This difference was >10° in 52 patients (56%) and >20° in 18 patients (19.4%). The mean difference between the postoperative sacral slope in a relaxed sitting position and the sacral slope in a flexed seated position was 11.3° (P < .0001). This difference was >10° in 51 patients (54.9%) and >30° in 14 patients (15.1%) postoperatively. Conclusions: There was a significant difference in sagittal pelvic tilt between the relaxed and flexed seated positions. A flexed seated view provides valuable information that might be more relevant for preoperative THA planning in order to prevent postoperative THA instability.

The Current Proposed Total Hip Arthroplasty Surgical Planning Guidelines Based on Classification of Spine Stiffness May be Flawed Due to Incorrect Assumptions.

BACKGROUND: The available classifications and preoperative planning tools for total hip arthroplasty assume that: 1) there is no variation in the sagittal pelvic tilt (SPT) if the radiographs are repeated, and 2) there is no significant change in the postoperative SPT postoperatively. We hypothesized that there would be significant differences in postoperative SPT tilt as measured by the sacral slope, thus rendering the current classifications and tools flawed. METHODS: This study was a multicenter, retrospective analysis of preoperative and postoperative (1.5-6 months) full-body imaging of 237 primary total hip arthroplasty (standing and sitting positions). Patients were categorized as 1) stiff spine (standing sacral slope sitting sacral slope < 10°) and 2) normal spine (standing sacral slope-sitting sacral slope ≥ 10°). Results were compared using the paired t-test. The posthoc power analysis showed a power of 0.99. RESULTS: The difference in mean standing and sitting sacral slope between the preoperative and postoperative measurements was 1°. However, in standing position, this difference was more than 10° in 14.4% of patients. In the sitting position, this difference was more than 10° in 34.2% of patients and more than 20° in 9.8% of patients. Postoperatively, 32.5% of patients switched groups based on the classification, which rendered the preoperative planning suggested by the current classifications flawed. CONCLUSION: Current preoperative planning and classifications are based on a single acquisition of preoperative radiographs without the incorporation of possible postoperative changes in SPT. Validated classifications and planning tools should incorporate repeated measurements to determine the mean and variance in SPT and consider the significant postoperative changes in SPT.

Comparison of silver-embedded occlusive dressings and negative pressure wound therapy following total joint arthroplasty in high BMI patients: a randomized controlled trial.

INTRODUCTION: High body mass index (BMI) and wound drainage following total joint arthroplasty (TJA) can lead to wound healing complications and periprosthetic joint infection. Silver-embedded occlusive dressings and negative pressure wound therapy (NPWT) have been shown to reduce these complications. The purpose of this prospective trial was to compare the effect of silver-embedded dressings and NPWT on wound complications in patients with BMI ≥ 35 m/kg2 undergoing TJA. METHODS: We conducted a randomized control trial of patients who had a BMI > 35 m/kg2 and were undergoing primary TJA between October 2017 and February 2020. Patients who underwent revision surgery, or those with an active infection, previous scar, history of wound healing complications, post-traumatic degenerative joint disease with hardware, or inflammatory arthritis were excluded. Patients were randomized to receive either a silver-embedded occlusive dressing (control) or NPWT. Frequency distributions, means, and standard deviations were used to describe patient demographics, postoperative complications, 90-day readmissions, and reoperations. T-test and chi-squared tests were used to test for significant differences between continuous and categorical variables, respectively. RESULTS: Two hundred-thirty patients with 3-month follow-up were included. One-hundred-fifteen patients received the control and 115 patients received NPWT. There were six patients (5.2%) in the control group with wound complications (drainage: n = 5, non-healing wound: n = 1) and two patients (1.7%) in the NPWT with complications (drainage: n = 2). There were no 90-day readmissions in the control group versus two (1.8%) 90-day readmissions in the NPWT group. Finally, three patients (2.6%) in the control group underwent reoperations (irrigation and debridement [I&D], I&D with modular implant exchange, and implant revision), while none in the NPWT group had undergone reoperation. The two groups showed insignificant differences in wound complications (p = 0.28), 90-day readmissions (p = 0.50), and reoperations (p = 0.25). CONCLUSION: Patients with BMI ≥ 35 m/kg2 undergoing TJA have no statistical difference in early wound complications, readmissions, or reoperations when treated with either silver-embedded dressings or NPWT.

A Multicenter Prospective Investigation on Patient Physical and Mental Health After Girdlestone Resection Arthroplasty.

BACKGROUND: Girdlestone resection arthroplasty is a salvage procedure for hip periprosthetic joint infection (PJI) that controls infection and reduces chronic pain, but may result in limited postoperative joint function. The aim of this study was to assess physical function and mental health after Girdlestone. METHODS: This was a multicenter, prospective study evaluating patients with Girdlestone. The Prosthesis Evaluation Questionnaire (PEQ) and patient-reported outcomes measurement information system (PROMIS) global physical health and mental health surveys were administered postoperatively via telephone. The PEQ consists of four scales (ie, ambulation, frustration, perceived response, and social burden) with scores ranging from 0 to 10. The PROMIS measures generated T-scores (mean: 50, standard deviation: 10) that enable comparison to the general population. RESULTS: Thirty-five patients completed all surveys. The average time from procedure to survey completion was 6 years (range, 1 to 20). The median scores for the ambulation, frustration, perceived response, and social burden scales of the PEQ were 0.0 [interquartile range: 0-4.1], 6.0 [3.0-9.3], 9.0 [7.2-10.0], and 7.5 [4.3-9.5]. The median raw scores of the PROMIS global physical health and mental health were 11.91 [interquartile range: 9-14] and 14.0 [10.0-16.0]. These corresponded to average T scores of 39.7 (standard error : 4.3) for physical health and 46.1 (standard error: 3.8) for mental health, which were 10.3 points and 3.9 points below the average score in the United States general population, respectively. CONCLUSION: Girdlestone can have a substantial negative impact on physical functions; however, mental health and social interaction may be only moderately affected. These outcomes can be used to guide patient expectations, as this procedure may be necessary in certain salvage scenarios.

Short-term outcomes of thin highly cross-linked polyethylene liners in primary total hip arthroplasty.

INTRODUCTION: The use of thin highly cross-linked polyethylene (HXLPE) liners in total hip arthroplasty (THA) allows utilisation of larger femoral heads. However, concern surrounding postoperative complications remains. This study aims to investigate rates of revision and re-admission associated with thin HXLPE liners at short-term follow-up. METHODS: We retrospectively reviewed 3047 patients who underwent THA with a cementless modular acetabular implant with a 36-mm femoral head, and different thicknesses of HXPLE liners from 2011 to 2021. We identified 723 patients (23.7%) with a minimum 2-year follow-up and 206 patients (6.8%) with a minimum 5-year follow-up. Patients in the thin group (TG, n = 1020) received <5.1-mm liners with 52-mm size cups while patients in the non-thin group (NTG, n = 2027) received >5.1-mm liners with >52-mm size cups. Outcomes were compared using multi-variable logistic regressions while controlling for all significant demographic differences. RESULTS: We found no significant differences in re-admission (3.9% vs. 4.3%, OR 0.97; 95% CI, 0.63-1.49; p = 0.874) and revision (2.5% vs. 3.2%, OR 0.72; 95% CI, 0.41-1.26; p = 0.246) rates between groups. The difference in fracture rate between groups was not significant, but the 1 recorded acetabular fracture (5%) occurred in the NTG. Although the rate of liner exchange was lower in the TG (1.1%) compared to the NTG (2.3%), the difference was not statistically significant (OR 0.51; 95% CI, 0.24-1.05; p = 0.068). Liners were exchanged for liner wear in 1 hip (1%), aseptic reasons in 38 hips (66%), and peri-prosthetic joint infection in 19 hips (33%). CONCLUSIONS: Patients undergoing THA with a thin liner were not significantly predisposed to higher rates of revision surgery or poorer clinical outcomes at short-term follow-up when compared to those who received a thicker liner. Consequently, further long-term studies regarding the utility of thin HXLPE implants in reducing complications should be pursued.

Bipolar Sealers and Tourniquet Use Have Similar Outcomes in Total Knee Arthroplasty.

Introduction: The use of tourniquets and bipolar sealers are effective methods of hemostasis during total knee arthroplasty (TKA). However, their effect on perioperative patient outcomes is unknown. The purpose of this study is to compare the efficacy of tourniquet-less, tourniquet-less with use of a bipolar sealer, and tourniquet use on postoperative pain and surgical outcomes following TKA. Methods: A retrospective study of prospectively collected data of 120 primary TKA cases was conducted at an urban academic hospital. Primary outcomes were visual analog scale (VAS) scores and opioid consumption (in morphine milligram equivalents). Demographics, length of stay (LOS), perioperative complications, and change in Knee Injury and Osteoarthritis Outcome Score (ΔKOOS) were also collected. Patients were divided into cohorts based on the use of tourniquet-less with bipolar sealer (TRLB) (n = 40), tourniquet (TR) (n = 40), or tourniquet-less (TRL) (n = 40). Results: There were no differences in demographic data between each cohort. TRLB, TR and TRL had similar LOS (2.68 ± 1.63 vs 2.29 ± 1.27 vs 2.36 ± 1.42 days; p = 0.472) and VAS pain score on postoperative day 1 (4.68 vs 3.74 vs 3.63; p = 0.209). There were also no differences in opioid consumption at 2 weeks (p = 0.903), 1 month (p = 0.973), 3 months (p = 0.983), or 5 months (p = 0.983) post-operatively. TRLB and TR had comparable improvement in ΔKOOS from baseline to 12 weeks post-operatively (Δ16.58 ± 8.47 vs Δ23.92 ± 14.60; p = 0.254). Compared to the ΔKOOS of TRL (Δ5.19 ± 2.59), TRLB and TR had clinically and statistically greater ΔKOOS improvements (p = 0.009; p = 0.001). The TRL cohort also had a higher readmission rate than TRLB and TR (15% vs 0% vs 5%, p = 0.025). Conclusion: Our findings demonstrate that both bipolar sealer and tourniquet use in TKA are associated with similar postoperative pain levels and LOS in comparison to tourniquet-less only TKA. However, bipolar sealer and tourniquet use may lead to better longer term improvement such as greater PRO score improvement and fewer readmissions.

Trends of obesity rates between primary total hip arthroplasty patients and the general population from 2013 to 2020.

BACKGROUND: The prevalence of obesity in total hip arthroplasty (THA) patients has been studied in the past. However, there has not been direct comparison against obesity in the general population. This study compared yearly trends in BMI and obesity rates between patients who had undergone primary THA and those from the general patient population. METHODS: We retrospectively reviewed all patients over the age of 18 who underwent primary, elective THA and those who had an annual routine physical exam between January 2013 and December 2020 at our academic tertiary medical center. Baseline demographics were controlled in our statistical models. Significance of yearly trends was determined through a linear regression analysis. Independent samples t-test and Chi-square test were used to compare means and proportions between the two groups, respectively. RESULTS: A total of 11,250 primary THA patients and 1,039,918 annual physical exam patients were included. Average BMI for the THA group was significantly higher (P < 0.001) each year compared to the annual physicals group (APG). Higher obesity rates were observed in all obesity subgroups (all classes, and class I-III individually) for THA patients each year compared to the APG. Interestingly, while we found a significantly increasing trend in obesity for the general population (P < 0.001), BMI and obesity rates remained stable in the THA population. CONCLUSION: While our general patient population showed significant increase in BMI and obesity over time, THA patients had higher, yet stable, BMI. Further investigation is required to determine the role of risk optimization in these findings. LEVEL III EVIDENCE: Retrospective Cohort Study.

Utilizing a Standardized Handoff Initiative Incorporating Both Medical Clearance Postoperative Recommendations and Orthopaedic-Specific Context to Improve Information Transfer.

Patients undergoing total joint arthroplasty (TJA) with multiple comorbidities require medical clearance recommendations from their primary care provider, which if not adhered to can lead to adverse postoperative complications. In this quality improvement initiative, we explore the impact of a standardized handoff process incorporating medical clearance postoperative recommendations and orthopaedic-specific context on information transfer in TJA. A systematic review of quantitative and qualitative studies from 2014 to 2019 was completed to draw a conclusion about the best practice methods for the development of a standardized handoff process. Prior to implementation, evidence was reviewed to inform activities such as baseline chart audits, attainment of stakeholder input regarding handoff, exploration of wound closure equipment utilization, and standardization of a structured "smart phase" that incorporates medical clearance recommendations and orthopaedic-specific context information. After provider education was completed and the new handoff approach initiated, data were collected to compare postintervention outcomes such as transfer of information and wound kit distribution cost analysis. At baseline, 42% of patients had medical clearance postoperative recommendations handed off when they were provided. At completion, the new handoff smart phrase was used 97% for the first handoff and 100% for the second handoff. Medical clearance postoperative recommendations were captured in the electronic health record 83% of the time when they were provided. When the new smart phrases were utilized, wound closure, precautions, and postoperative void status were always handed off. Once wound closure technique was specified, bedside nurses were able to provide the appropriate wound closure removal equipment at discharge, projecting cost savings of $0.69 per case (∼234 cases per month). The use of a standardized handoff smart phrase that includes specialty specific context and postoperative medical management requirements successfully improved the information transfer between providers in a large academic orthopaedic medical center.

Impact of Preoperative Anemia Severity on Primary Total Hip Arthroplasty Outcomes.

BACKGROUND: Preoperative anemia (POA) is a significant predictor for adverse outcomes in primary total hip arthroplasty (THA). Current literature has studied POA stratified by severity. This study aims to find a threshold preoperative hemoglobin (Hb) value for increased risk of adverse outcomes in THA. METHODS: This is a retrospective analysis of primary THA patients with preoperative Hb values from 2014 to 2021 from an academic orthopedic specialty hospital. Demographics, surgical data, and postoperative outcomes were collected. Patients without preoperative Hb values within the electronic health record system or values acquired >30 days preoperatively were excluded. Patients were grouped based on POA severity using World Health Organization criteria. Secondary analysis using discrete preoperative Hb values was performed. P-values were calculated using analysis of variance/Kruskal-Wallis and chi-squared/Fisher's exact testing with P < .05 considered significant. RESULTS: A total of 1347 patients were included: 771 (57.2%) patients with POA and 576 (42.8%) with normal preoperative Hb. In the POA group, 292 (37.9%) were mild, 445 (57.7%) moderate, and 34 (4.4%) severe. Increased length of stay was seen in moderate (3.9 ± 4.3 vs 2.4 ± 2.1, P < .001) and severe (5.0 ± 3.4 vs 2.4 ± 2.1, P < .0001) groups compared to control. The severe group had higher 90-day readmission and revision rates compared to control. Analysis by discrete Hb values showed increased length of stay in Hb values <11 g/dL and a greater proportion of patients with Hb values <12 g/dL were discharged to skilled nursing facilities. CONCLUSION: Patients with preoperative Hb <12 g/dL should be assessed for other risk factors that may predispose them to postoperative complications. Further investigation is warranted to develop more robust perioperative management strategies for POA patients undergoing THA. LEVEL III EVIDENCE: Retrospective Cohort Study.

Postoperative venous thromboembolism event increases risk of readmissions and reoperation following total joint arthroplasty: a propensity-matched cohort study.

PURPOSE: The clinical impact of postoperative venous thromboembolism (VTE) following total joint arthroplasty (TJA) remains unclear. In this study, we evaluate the effect of VTE following TJA on postoperative outcomes including discharge disposition, readmission rates, and revision rates. METHODS: We retrospectively reviewed all patients over the age of 18 who underwent primary, elective THA or TKA between 2013 and 2020. Patients were stratified into two cohorts based on whether or not they had a VTE following their procedure. Baseline patient demographics and clinical outcomes such as readmissions and revisions were collected. Propensity score matching was performed to limit significant demographic differences, while independent sample t-tests and Pearson's chi-squared test were used to compare outcomes of interest between the groups. RESULTS: After propensity score matching, there were 109 patients in each cohort, representing a total of 218 patients for the matched comparison. Prior to matching, the VTE cohort was noted to have a significantly higher BMI than the non-VTE cohort (32.22 ± 6.27 vs 30.93 ± 32.04 kg/m2, p = 0.032). All other patient demographics were similar. Compared to the non-VTE cohort, the VTE cohort was less likely to be discharged home (66.1% vs 80.7%; p = 0.021), had a higher rate of 90-day all-cause readmissions (27.5% vs 9.2%, p = 0.001), and a higher two-year revision rate (11.0% vs 0.9%, p = 0.003). CONCLUSION: Patients with postoperative VTE were less likely to be discharged home and had higher 90-day readmission and two-year revision rates. Therefore, mitigating perioperative risk factors, initiating appropriate long-term anticoagulation, and maintaining close follow-up for patients with postoperative VTE may play significant roles in decreasing hospital costs and the economic burden to the healthcare system. LEVEL OF EVIDENCE III: Retrospective Cohort Study.

Trends of Obesity Rates Between Patients Undergoing Primary Total Knee Arthroplasty and the General Population from 2013 to 2020.

BACKGROUND: Obesity is a recognized risk factor for severe knee osteoarthritis. However, it remains unclear how obesity prevalence trends in the current population undergoing total knee arthroplasty (TKA) compare with those seen in individuals not undergoing this procedure. In this study, we assessed the yearly trends in body mass index (BMI) and obesity rates between patients who have undergone primary TKA and those in the general population. METHODS: We retrospectively reviewed all patients ≥18 years of age from January 2013 through December 2020 who underwent primary, elective TKA and those who had an annual routine physical examination at our institution within the same period. Baseline demographic characteristics were collected. The independent samples t test was used to compare means and the chi-square test was used to compare proportions between the 2 cohorts, and a linear regression was used to determine the significance of the yearly trends. RESULTS: A total of 11,333 patients who underwent primary TKA and 1,158,168 patients who underwent an annual physical examination were included in this study. After adjusting for age, we found the mean BMI for the TKA group to be significantly greater (p < 0.001) every year compared with the annual physicals group. The proportion of patients who were categorized into any obesity class (BMI, ≥30 kg/m2), Class-I obesity (BMI, 30 to 34.9 kg/m2), Class-II obesity (BMI, 35 to 39.9 kg/m2), and Class-III obesity (BMI, ≥40 kg/m2) was significantly higher for the TKA group each year compared with the annual physicals group. An analysis of trends over time showed a significantly increasing trend (p < 0.001) in BMI and obesity rates for the annual physicals group, but a stable trend for patients undergoing TKA. CONCLUSIONS: Patients who underwent TKA continued to have higher BMI than the general population, which showed a steady increase over time. Physicians need to continue in their efforts to educate patients on weight management and healthy lifestyles to potentially delay the need for a surgical procedure. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Robotic-Assisted Total Hip Arthroplasty in Patients Who Have Developmental Hip Dysplasia.

INTRODUCTION: Total hip arthroplasty (THA) in the setting of developmental dysplasia of the hip (DDH) presents more inherent complexities than routine primary THA for osteoarthritis. These include acetabular bone deficiency, limb length discrepancy (LLD), and abnormal femoral anteversion. Three-dimensional planning and robot-assisted (RA) bone preparation may simplify these complex procedures and make them more reproducible. The purpose of this study was to evaluate radiographic and clinical outcomes in a cohort of patients who had DDH and underwent an RA THA. MATERIALS AND METHODS: We retrospectively analyzed 26 DDH patients who underwent RA THA by a single surgeon between 2013 and 2019. Their mean age was 54 years (range, 29 to 72 years) and mean follow up was approximately two years. Medical records were reviewed for demographics, clinical scores, Crowe classifications, and complications. There were thirteen Crowe I and seven Crowe II DDH hips, who were routinely managed with primary cementless implants. Two patients who had Crowe III and four patients who had Crowe IV DDH were also identified. All hips were reconstructed with cementless hemispherical acetabular components with or without the use of screws, but no acetabular augments or bulk allografts. Implants allowing control of femoral anteversion were selected in 23.1% of cases, including all six cases with Crowe III or IV dysplasia, and the need for these implants was uniformly identified using preoperative information about femoral version provided by the three-dimensional planning software. No patient was managed with a shortening femoral osteotomy. Postoperative radiographs were examined for LLD, center of rotation (COR), cup position (inclination and anteversion), and component osseous-integration. RESULTS: Mean radiographic LLD was 1.7mm (range, -9 to +14) in patients who had Crowe I DDH, and there was no clinical LLDs greater than 5mm observed. Although patients who had Crowe II and greater DDH had a mean radiographic LLD of -11.6mm (range, -26 to +2.2), again no clinical LLD greater than 5mm was observed other than one patient who had bilateral Crowe II DDH in whom 10mm of clinical lengthening was accepted at the index arthroplasty with the plan to match lengths when her contralateral THA was performed. There were no cases of dislocation or acetabular fixation failure. One patient who had a femoral deformity and an intra-osseous blade plate from a prior femoral osteotomy suffered a failure of femoral osseous-integration, resulting in revision. A 32-point increase in mean modified Harris Hip Score (mHHS) was found (p=0.002), from 48 points preoperatively to 80 points postoperatively. DISCUSSION: RA THA provides an excellent option for the arthroplasty surgeon to both preoperatively localize and characterize the acetabular deficiency, while providing a targeted, optimal, and secure placement of the components intraoperatively. Our results suggest favorable outcomes when compared to previous research on manual THA in DDH. Further studies, including comparative analyses, could discern possible advantages over traditional THA without robotic assistance in DDH. CONCLUSION: Total hip arthroplasty (THA) in the setting of developmental dysplasia presents more inherent complexities than routine primary THA. Robotic-assisted THA may simplify these complex procedures.