Abdel, Matthew P

Background: Surgeons often recommend weight loss for patients with obesity before total knee arthroplasty (TKA). However, it is unknown whether preoperative weight loss affects outcomes. The goals of this study were to determine how many patients with obesity lost weight before TKA, to identify weight loss predictors, and to evaluate if preoperative weight loss affected postoperative outcomes. Methods: Among 23,726 primary TKAs performed between 2002 and 2019, we identified 3,665 patients who had a body mass index (BMI) of ≥30 kg/m 2 measured 1 to 24 months before surgery and had a weight measured at surgery. The mean patient age was 68 years, and 59% of patients were female. The mean patient BMI was 36 kg/m 2 . Univariable linear regressions evaluated weight loss predictors. Univariable and multivariable logistic regressions and Cox proportional hazards models evaluated the impact of preoperative weight change on discharge, operative time, periprosthetic joint infections (PJIs), complications, revisions, and reoperations. The mean follow-up was 6 years. Results: Overall, 20% of patients gained ≥5 pounds (1 pound = 0.45 kg), 39% maintained weight, 17% lost 5 to <10 pounds, 15% lost 10 to <20 pounds, and 9% lost ≥20 pounds before TKA. Male patients lost slightly more weight (−4.6 pounds) than female patients (−4.3 pounds) (p = 0.05). In univariable analyses, gaining >5 pounds was associated with increased odds of extended hospital length of stay (odds ratio [OR], 1.4; p = 0.01) and risk of complications (hazard ratio [HR], 1.7; p < 0.01). Losing 10 to <20 pounds was associated with increased risks of revision (HR, 2.0; p = 0.01), PJI (HR, 3.1; p < 0.01), and complications (HR, 1.6; p = 0.03). In multivariable analyses, compared with maintaining weight, losing 10 to <20 pounds was associated with an increased risk of PJI (HR, 2.6; p = 0.01), whereas gaining >5 pounds was associated with an increased risk of complications (HR, 1.5; p = 0.03). Conclusions: Few patients with obesity lost substantial weight before primary TKA, and reaching common preoperative weight loss goals was not associated with improved outcomes. Although a healthy weight is important for general health, weight loss before TKA may not be sufficient to improve postoperative outcomes for most patients with obesity. Level of Evidence: Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Background: The U.S. Food and Drug Administration has approved a bupivacaine and meloxicam extended-release (ER) intra-articular injection for pain during total knee arthroplasty (TKA). However, the real-world evidence with regard to analgesic efficacy of that medication has been limited. This randomized clinical trial investigated the efficacy of this new medication compared with our standard periarticular injection for postoperative analgesia after primary TKA. Methods: Eligible patients undergoing primary, unilateral TKA for osteoarthritis at our academic center were enrolled. Patients were blinded and were randomized 1:1 to the bupivacaine-meloxicam ER (ZYNRELEF) injection group or the standard injection (ropivacaine, ketorolac, epinephrine) control group. A standardized, multimodal analgesic pathway was implemented. Numeric Rating Scale (NRS) pain scores and tallies of opioid consumption were collected. The primary outcome was the area under the curve (AUC) for NRS pain, adjusted for opioid consumption, over 72 hours. The minimal clinically important difference was considered to be 30%. Power analysis determined a minimum of 44 patients per group. The final groups included 53 patients in the experimental group and 48 patients in the control group. Results: Similar postoperative analgesia was observed, with an AUC for the adjusted NRS pain score up to 72 hours of 331 in the experimental group and 373 in the control group (p = 0.09). The mean maximum NRS pain scores were similar and reflected good, but not complete, analgesia. Scores were 3 to 5 on the day of the surgery, 4 to 6 on postoperative day (POD) 1, 5 to 6 on POD 2, and 4 to 5 on POD 3 (p > 0.05). One patient in the experimental group and 2 patients in the control group had early postoperative complications, none of which was deemed to be related to the analgesic choice. Conclusions: This randomized clinical trial demonstrated similar analgesia with a bupivacaine-meloxicam ER solution and a standard periarticular injection up to 72 hours after primary TKA. Cost, reimbursement, and convenience may ultimately prove to be more important than analgesic differences when choosing between these 2 effective options for managing postoperative pain. Level of Evidence: Therapeutic Level I . See Instructions for Authors for a complete description of levels of evidence.

Background: Periprosthetic tibial fractures around a total knee replacement (TKR) remain challenging to manage, with little published information for guidance. The purpose of this study was to review the types, management techniques, and outcomes of periprosthetic tibial fractures in the largest series to date. Methods: We identified 300 periprosthetic tibial fractures (285 patients) around a TKR (43% in primary TKRs and 57% in revision TKRs) sustained between 1996 and 2020. Fractures were classified according to Felix et al. as Type I (tibial plateau), Type II (adjacent to stem), Type III (distal to stem), or Type IV (tibial tubercle), with subtypes A (well-fixed component), B (loose component), and C (intraoperative fracture). Of the fractures in this study, 53% were Type I, 24% were Type II, 16% were Type III, and 8% were Type IV. A total of 46% of fractures occurred intraoperatively, and 54% of fractures occurred postoperatively (61% subtype A, 39% subtype B). The mean patient age at fracture was 67 years, and 64% of patients were female. The mean follow-up was 6 years. Results: The intraoperative fracture incidence was 1.40% in revision TKRs and 0.10% in primary TKRs. Among intraoperative fractures, the 2-year survivorship free from tibial component revision was highest in Type I (100%) and lowest in Type IV (67%) (p < 0.001). For postoperative fractures, the 2-year survivorship free from any reoperation was 29% and the 2-year survivorship free from tibial component revision was 51%. Type-I postoperative fractures had the lowest 2-year survivorship free from tibial component revision (10%), whereas Type-III fractures had the highest survivorship (88%) (p < 0.001). Conclusions: Intraoperative periprosthetic fracture of the tibia was fourteenfold more likely in revision TKRs compared with primary TKRs. Among all intraoperative fractures, Type-I fractures were well-tolerated, with 100% survivorship free from tibial component revision at 2 years. Conversely, Type-I postoperative fractures had only 10% survivorship at 2 years. Level of Evidence: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Background: Many surgeons use body mass index (BMI) cutoffs when offering total hip arthroplasty (THA). However, little is known about who loses weight before THA, and if weight loss improves outcomes. This study determined how many patients lost weight before primary THA, identified predictors of preoperative weight loss, and evaluated whether preoperative weight loss was associated with improved outcomes. Methods: Among 53,038 primary THAs that were performed between 2002 and 2019, we identified 2,463 patients who had a BMI of ≥30 kg/m 2 (measured 1 to 24 months before surgery) and had their weight measured at the time of surgery. The mean age was 66 years; 47% were women. The mean BMI was 35 kg/m 2 . Nonparametric models evaluated potential associations with weight loss. Univariable and multivariable logistic regression and Cox proportional hazards models evaluated the impact of preoperative weight change on hospital length of stay, discharge disposition, operative time, periprosthetic joint infection (PJI), complications, revision, and reoperation. The mean follow-up was 5 years. Results: Overall, 17% of the patients gained >5 pounds (2.27 kg), 38% maintained their weight, 16% lost 5 to <10 pounds (4.54 kg), 17% lost 10 to <20 pounds (9.07 kg), and 12% lost ≥20 pounds before THA. Only 28% of patients with a preoperative BMI of ≥40 kg/m 2 achieved a BMI of <40 kg/m 2 by the time of surgery; those who did required a mean of 1.3 years to lose the weight. In multivariable analyses, there were no significant improvements in operative time, length of stay, and discharge disposition, or survivorship free of PJI, complication, revision, or reoperation for any weight-loss category when compared with those who maintained their weight. Conclusions: Only 12% of patients lost ≥20 pounds, and only 28% of patients with a BMI of ≥40 kg/m 2 achieved a BMI of <40 kg/m 2 before primary THA. There was no decrease in complications, revisions, or reoperations for any preoperative weight-loss category when compared with those who maintained their weight. While weight loss benefits overall health, the results of this study call into question whether preoperative weight loss alone is enough to reduce postoperative complications for most patients. Level of Evidence: Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Background: The relative advantages and disadvantages of 2-stage versus 1-stage management of infection following total hip arthroplasty (THA) are the current subject of intense debate. To understand the merits of each approach, detailed information on the short and, importantly, longer-term outcomes of each must be known. The purpose of the present study was to assess the long-term results of 2-stage exchange arthroplasty following THA in one of the largest series to date. Methods: We identified 331 periprosthetic joint infections (PJIs) that had been treated with a 2-stage exchange arthroplasty between 1993 and 2021 at a single institution. Patients were excluded if they had had prior treatment for infection. The mean age at the time of reimplantation was 66 years, 38% of the patients were female, and the mean body mass index (BMI) was 30 kg/m 2 . The diagnosis of PJI was based on the 2011 Musculoskeletal Infection Society criteria. A competing-risk model accounting for death was utilized. The mean duration of follow-up was 8 years. Results: The cumulative incidence of reinfection was 7% at 1 year and 11% at 5 and 10 years. Factors predictive of reinfection included BMI ≥30 kg/m 2 (hazard ratio [HR] = 2; p = 0.049) and the need for a spacer exchange (HR = 3.2; p = 0.006). The cumulative incidence of any revision was 13% at 5 and 10 years. The cumulative incidence of aseptic revision was 3% at 1 year, 7% at 5 years, and 8% at 10 years. Dislocation occurred in 33 hips (11% at 10 years); 15 (45%) required revision. Factors predictive of dislocation were female sex (HR = 2; p = 0.047) and BMI <30 kg/m 2 (HR = 3; p = 0.02). The mean Harris hip score (HHS) improved from 54 to 75 at 10 years. Conclusions: In this series of 331 two-stage exchange arthroplasties that were performed for the treatment of infection, we found a low rate of aseptic revision (8%) and a low rate of reinfection (11%) at 10 years. These long-term mechanical and infection data must be kept in mind when considering a paradigm shift to 1-stage exchanges. Level of Evidence: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Background: Total joint arthroplasty (TJA) is increasingly being performed as an outpatient (i.e., same-day discharge) procedure. Postoperatively, orthostatic hypotension or pain-related tachycardia can lead to concerns regarding the hemoglobin (Hgb) level of the patient prior to discharge. The purpose of this study was to prospectively assess the reliability and accuracy of, and patient and nurse satisfaction with, postoperative noninvasive hemoglobin (nHgb) monitoring compared with an invasive serum hemoglobin (iHgb) laboratory draw in the outpatient TJA setting. Methods: We prospectively enrolled 200 patients undergoing outpatient unilateral TJA, of whom 157 were ultimately included in our analysis (94 hips, 63 knees). Postoperatively, both nHgb and iHgb values were obtained at a mean of 36 minutes apart. Surveys were completed by patients and nurses. The strength of the agreement between the 2 Hgb monitoring methods was evaluated with use of the Bland-Altman 95% limits of agreement, concordance correlation coefficient (CCC), and intraclass correlation coefficient (ICC). Receiver operating characteristic curve analyses were performed to investigate the ability of nHgb monitoring to predict an iHgb of <11.2 g/dL (the 5th-percentile iHgb value). Results: The mean preoperative iHgb was 14.2 ± 1.1 g/dL. The mean postoperative iHgb and nHgb values were 13.3 ± 1.5 and 13.3 ± 1.2 g/dL, respectively. The Bland-Altman 95% limits of agreement were −3.2 and +3.1 g/dL, indicating that 95% of patients’ iHgb values are expected to fall between these limits relative to the nHgb value of the patient. The CCC and ICC were both 0.33. An nHgb cutoff value of <12.7 g/dL had 100% sensitivity and 67% specificity for detecting an iHgb of <11.2 g/dL. Patients reported less pain with the nHgb test than with the iHgb test (mean pain score, 0.0 versus 1.8; p < 0.001), and 97% of patients preferred the nHgb test. Following the nHgb test, 73% of responding patients and 83% of responding nurses were “somewhat more reassured” to “significantly more reassured” about same-day discharge. Conclusions: Routine nHgb testing can rapidly screen patients undergoing outpatient TJA for acute anemia prior to discharge. With an nHgb of <12.7 g/dL, there was perfect sensitivity and 67% specificity for detecting an iHgb of <11.2 g/dL. Most patients and nurses felt more reassured about same-day discharge after nHgb monitoring. Level of Evidence: Diagnostic Level II . See Instructions for Authors for a complete description of levels of evidence.

Aims Cutibacterium acnes ( C. acnes ; previously known as Propionibacterium acnes or P. acnes ) periprosthetic hip and knee infections are under-reported. While culture contamination with C. acnes occurs, true infections are important to recognize and treat. We sought to describe the demographics and treatment outcomes of patients with C. acnes periprosthetic joint infections (PJIs) of the hip and knee. Methods Patients with C. acnes PJI between January 2005 and December 2018 were retrospectively reviewed utilizing the institutional total joint registry. Patients with monomicrobial PJI and two or more positive cultures were considered to have true C. acnes PJI. Patients with polymicrobial infection or with only one positive culture were excluded. This resulted in 35 PJIs (21 hips and 14 knees); the patients’ mean age was 63 years (35 to 84) and 15 (43%) were female. Mean follow-up was five years (1 to 14). Results The median time to positive culture was five days (IQR 5 to 6) and median synovial fluid cell count was 22,583 cells (IQR 15,200 to 53,231). The median ESR was 25 mm/hr (IQR 7 to 37), and CRP was 15 mg/l (IQR 3 to 29). Of the 35 PJIs, 18 (51%) were treated with chronic antibiotic suppression without surgical intervention, and the remainder were treated with two-stage exchange arthroplasty. The two-year survival free of any revision was 94%. Four patients failed treatment due to symptomatic infection, with three treated with two-stage exchange and one treated with irrigation and debridement with modular component exchange for a survival rate of 89% and 83% at two and five years, respectively. Conclusion Laboratory evidence of C. acnes PJI in this cohort was typical compared to more conventional organisms. Cultures grew more quickly than previously thought in patients with C. acnes PJI. Treatment with two-stage exchange or chronic antibiotic suppression alone both had few treatment failures at mid-term follow-up. Cite this article: Bone Joint J 2024;106-B(12):1426–1430.

Background: Second-generation highly cross-linked polyethylene (HXLPE) has revolutionized total hip arthroplasty. However, the long-term risks and benefits of HXLPE in primary total knee arthroplasty (TKA) remain unknown. This randomized clinical trial evaluated implant survivorship, complications, radiographic results, and clinical outcomes of HXLPE and conventional ultra-high molecular weight polyethylene (UHMWPE) inserts in primary TKAs. Methods: We enrolled 518 patients (518 knees) who underwent primary TKA in 3 centers within 1 tertiary referral network. The mean age was 67 years, the mean body mass index was 32 kg/m 2 , and 58% of the patients were women. All of the patients underwent primary TKA with a cemented posterior-stabilized tibial insert and patellar resurfacing. Randomization proceeded via stratified dynamic allocation. The patients were blinded to their study group allocation: those in the control group (254 knees) underwent TKA with an UHMWPE insert (N2Vac; Stryker); those in the treatment group (264 knees) received an HXLPE insert (X3; Stryker). Kaplan-Meier survivorship, radiographic results, and clinical outcomes were assessed. This trial was registered with ClinicalTrials.gov. The mean follow-up was 11 years. Results: The 10-year overall survivorship free from any revision and from any reoperation was 96% and 94%, respectively. There were no differences in the risk of revision or reoperation between the groups (p > 0.05). There were a total of 19 revisions. Revision indications included periprosthetic joint infection (14 knees), instability (4 knees), and open reduction and internal fixation (ORIF) for a patellar fracture due to osteolysis around a UHMWPE insert (1 knee). There were no revisions due to polyethylene wear, osteolysis, or fracture of the post in the HXLPE group. The radiographic results and clinical outcomes were otherwise similar. Conclusions: Notably, no wear-related failures were identified in the HXLPE group, but there was 1 case of osteolysis in the UHMWPE group. Level of Evidence: Therapeutic Level I . See Instructions for Authors for a complete description of levels of evidence.

AimsThe prevalence of obesity is increasing substantially around the world. Elevated BMI increases the risk of complications following total hip arthroplasty (THA). We sought to evaluate trends in BMI and complication rates of obese patients undergoing primary THA over the last 30 years.MethodsThrough our institutional total joint registry, we identified 15,455 primary THAs performed for osteoarthritis from 1990 to 2019. Patients were categorized according to the World Health Organization (WHO) obesity classification and groups were trended over time. Cox proportional hazards regression analysis controlling for confounders was used to investigate the association between year of surgery and two-year risk of any reoperation, any revision, dislocation, periprosthetic joint infection (PJI), venous thromboembolism (VTE), and periprosthetic fracture. Regression was stratified by three separate groups: non-obese; WHO Class I and Class II (BMI 30 to 39 kg/m2); and WHO Class III patients (BMI ≥ 40 kg/m2).ResultsThere was a significant increase in the proportion of all obesity classes from 1990 to 2019, and the BMI values within each WHO class significantly increased over time. Risk of any reoperation did not change over time among non-obese or WHO Class I/II patients, but increased for WHO Class III patients (hazard ratio (HR) 1.04; p = 0.044). Risk of dislocation decreased over time for non-obese (HR 0.96; p < 0.001) and WHO Class I/II (HR 0.96; p = 0.002) patients, but did not change over time for WHO Class III (HR 0.94; p = 0.073) patients. Risks of any revision and PJI did not change over time for any group.ConclusionThe proportion of patients undergoing THA who are obese has increased dramatically at our institution between 1990 and 2019. Despite BMI values increasing within all WHO classes over time, two-year complication risks have remained stable or decreased in WHO Class I/II patients. However, continued efforts will be required to mitigate risks in the heaviest WHO Class III patients.Cite this article: Bone Joint J 2024;106-B(11):1223–1230.

Background: The rates of obesity among patients undergoing total knee arthroplasty (TKA) have substantially increased. In addition, obesity is a well-established risk factor for complications after TKA. The purpose of this study was to analyze trends in body mass index (BMI) and complication risk among obese patients undergoing primary TKA treated at a single institution over 3 decades. Methods: Utilizing an institutional total joint registry, 13,919 primary TKAs performed to treat osteoarthritis between 1990 and 2019 were identified. Patients were stratified by BMI according to the World Health Organization (WHO) classification into 3 groups: non-obese (BMI, <30 kg/m 2 ), WHO Class-I and II obese (BMI, 30 to 39.9 kg/m 2 ), and WHO Class-III obese (BMI, ≥40 kg/m 2 ). Trends in BMI and survivorship free from reoperation, revision, and periprosthetic joint infection (PJI) were analyzed over time while controlling for age, sex, and the Charlson Comorbidity Index. Results: Over the study period, there was a 90% increase in the prevalence of Class-II obesity (13% to 25%) and a 300% increase in Class-III obesity (3% to 12%). Analysis of the entire cohort demonstrated a decrease in the 2-year risk of any reoperation, any revision, and PJI (p < 0.05 for all) with time. The risk decreased significantly over time for non-obese patients for any reoperation (p = 0.029) and any revision (p = 0.004) and for Class-III obese patients for any reoperation (p = 0.038) and any revision (p = 0.012), but it remained stable for Class-I and II obese patients. The risk of PJI decreased from 1990 to 2019 for non-obese patients (p = 0.005), but there were no significant changes in PJI risk for any obesity group. Conclusions: Despite increasing rates of obesity among our patients who underwent TKA, we observed decreasing risks of reoperation, revision, and PJI over time. The risks of reoperation and revision declined among non-obese patients, remained stable for Class-I and II obese patients, and declined for Class-III obese patients. The PJI risk declined for non-obese patients over the study period, but no such decline occurred for any category of obesity. Despite the decreasing risks of reoperation and revision, further work is needed to improve PJI risk in obese patients. Level of Evidence: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.