Increasing Body Mass Index Not Associated With Worse Patient-Reported Outcomes After Primary THA or TKA.

INTRODUCTION: As the US obesity epidemic continues to grow, so too does comorbid hip and knee arthritis. Strict body mass index (BMI) cutoffs for total hip and knee arthroplasty (THA and TKA) in the morbidly obese have been proposed and remain controversial, although current American Academy of Orthopaedic Surgeons guidelines recommend a BMI of less than 40 m/kg2 before surgery. This study sought to compare patient-reported outcomes and 30-day complication, readmission, and revision surgery rates after THA or TKA between morbidly obese patients and nonmorbidly obese control subjects. METHODS: All patients undergoing primary THA and TKA at our institution from May 2020 to July 2022 were identified. Patient demographics, surgical time, length of stay and 30-day readmission, revision surgery, and complication rates were prospectively collected. Preoperative and postoperative Hip and Knee Society (Hip Osteoarthritis Outcome Score [HOOS] and Knee Osteoarthritis Outcome Score [KOOS]) were collected. Patients were stratified by BMI as ideal weight (20 to 24.9), overweight (25 to 29.9), class I obese (30 to 34.9), class II obese (35 to 39.9), and morbidly obese (>40 m/kg2). RESULTS: A total of 1,423 patients were included for final analysis. No difference was observed in 30-day unplanned return to emergency department, readmission, or revision surgery in the morbidly obese cohort. Morbidly obese patients undergoing THA had lower preoperative HOOS (49.5 versus 54.5, P = 0.004); however, there was no difference in postoperative HOOS or KOOS at 12 months across all cohorts. DISCUSSION: No difference was observed in 30-day return to emergency department, readmission, or revision surgery in the morbidly obese cohort. Despite a lower preoperative HOOS, there was no difference in 12-month HOOS or KOOS when stratified by BMI. These findings suggest that such patients may achieve similar benefit from arthroplasty as their ideal weight counterparts.

Preoperative Bladder Scanning Can Predict Postoperative Urinary Retention Following Total Joint Arthroplasty.

BACKGROUND: As total joint arthroplasty (TJA) moves to the outpatient setting, it is becoming clear that postoperative urinary retention (POUR) is a potential impediment to same-day discharge. Although risk factors for POUR have been widely studied, the lack of their clinical utility warrants investigation of specific preoperative factors that can assist in surgical planning and patient optimization. The purpose of the current study was to determine whether preoperative symptom surveys and bladder scanning are useful tools in identifying POUR risk. METHODS: We performed a prospective analysis of patients undergoing total hip arthroplasty (THA) and total knee arthroplasty (TKA) at a high-volume orthopaedic hospital between December 1, 2020, and September 30, 2021. A total of 507 patients (324 female and 183 male) undergoing TJA completed the American Urological Association (AUA) symptom index preoperatively and then again at 14 and 64 days postoperatively. Post-void bladder scans were obtained in the immediate preoperative setting. POUR was defined as a bladder volume of >500 mL that required catheterization. Chi-square and quintile analysis were used to compare bladder scanning volumes, and Student t tests were used to compare AUA scores. RESULTS: The rate of POUR was 37% (66 female and 34 male) and 23% (37 female and 19 male) in the TKA and THA groups, respectively. Increasing post-void residual volume (PVRV) measured on preoperative bladder scanning was found to be predictive of POUR. Among the TKA cohort, younger age and lower body mass index were also associated with increased catheterization, although age was not statistically significant. The AUA symptom survey was not found to correlate with POUR in either population. CONCLUSIONS: There was a predictable and exponential increase in the rate of catheterization as preoperative PVRV increased from 50 to 200 mL. The AUA symptom score showed no utility in predicting POUR in our study population. We propose that preoperative bladder ultrasonography become standard practice in TJA, especially among patients scheduled for same-day discharge. LEVEL OF EVIDENCE: Prognostic Level II . See Instructions for Authors for a complete description of levels of evidence.

Preoperative Factors to Assess Risk for Postoperative Urinary Retention in Total Joint Arthroplasty: A Retrospective Analysis.

BACKGROUND: Postoperative urinary retention (POUR) is a significant problem in total joint arthroplasty (TJA). Although risk factors for POUR have been well documented, they are ubiquitous in an aging total joint population, which makes risk stratification difficult. The purpose of this study was to determine if a high preoperative post-void bladder scan identifies patients at risk for POUR. METHODS: A retrospective analysis was conducted on all TJAs performed at a high-volume orthopedic center between December 2019 and February 2020. A total of 585 elective TJA patients received post-void bladder scans before surgery. Bladder scan volumes were correlated with catheterization via Chi-squared tests. RESULTS: A high post-void residual volume (PVRV > 50 ml) was associated with an increased risk of catheterization (23% vs 34%, chi-squared statistic = 6.2638, P value = .013), as was intravenous fluid volume (>1000 ml in knee, >2000 ml in hip). Catheterization rates were higher among total knee arthroplasty patients younger than 60 years (37% vs 24%, chi-squared statistic = 4.284, P value = .0385) and total hip arthroplasty (THA) patients older than 65 years (30% vs 18%, chi-squared statistic = 3.292, P value = .0695). Multiple risk factors were additive. CONCLUSIONS: Higher PVRV and intravenous fluids were independently associated with catheterization after TJA. Younger age was associated with greater risk in total knee arthroplasty, while older age increased risk in THA. We propose that a preoperative bladder scan to detect a high PVRV may provide clinical utility to identify patients likely to develop POUR.

Femoral Intramedullary Alignment in Total Knee Arthroplasty: Indications, Results, Pitfalls, Alternatives, and Controversies.

While femoral intramedullary alignment has been found to be the most accurate and reproducible method for proper femoral component orientation in total knee arthroplasty, certain situations preclude the use of intramedullary alignment, such as ipsilateral long-stem total hip arthroplasty, femoral shaft deformity (congenital or post-traumatic), capacious femoral canal, and retained hardware. These cases require alternative alignment guides, that is, extramedullary alignment. The purpose of this study was to determine the accuracy of intramedullary alignment in reproducing the femoral anatomic axis. Using 35 adult cadaveric femora without obvious clinical deformity, and 7 with proximal prosthetic devices blocking the passage of an intramedullary guide, the accuracy of the guide rod was assessed both anatomically and radiographically. In the seven femora with proximal femoral devices, the guide rod could not be completely seated, resulting in a greater degree of flexion of the guide rod compared with the mechanical axis of the femur, and a greater degree of varus compared with the anatomical axis, as compared with 35 femora without obvious deformity. In cases where seating of the intramedullary guide rod is either incomplete or impossible, extramedullary femoral guides allow more accurate determination of the distal femoral cut by referencing directly from the mechanical axis, that is, the center of the femoral head. We present case studies as examples of indications for use of an extramedullary femoral guide. In addition, we demonstrate two different techniques for extramedullary femoral alignment using fluoroscopic guidance in cases incompatible with intramedullary alignment.