Immediate weightbearing is safe after revision total hip arthroplasty for Vancouver B2/B3 periprosthetic femur fractures.

INTRODUCTION: Modular fluted, tapered stems provide a reliable treatment for Vancouver B2/B3 fractures. Historically, these patients had weightbearing restrictions postoperatively. Although full immediate postoperative weightbearing may provide benefits in this patient population, stem subsidence is a concern. QUESTIONS/PURPOSES: The objective of this study was to investigate the effect of post-operative weight-bearing status on stem subsidence in patients treated with modular tapered stems for Vancouver B2 and B3 periprosthetic fractures. We sought to answer two questions: (1) Does full immediate postoperative weightbearing after revision total hip arthroplasty for periprosthetic femur fracture lead to increased stem subsidence compared to protected weightbearing? (2) Is there a mortality difference between these two groups of patients with different weightbearing restrictions? METHODS: From 2009 to 2015 all patients who underwent revision for Vancouver B2/B3 fractures were made non-weightbearing (NWB) for six weeks postoperatively. After 2015, immediate weightbearing as tolerated (WBAT) was allowed postoperatively. We compared stem subsidence between immediate postoperative and final radiographs. Additionally, we performed a Kaplan-Meijer analysis with one-year mortality as an endpoint. RESULTS: The final cohort included forty-seven patients with an average follow-up of 254 days. The average stem subsidence was 1.0 mm (95 % CI, 0.5-1.5 mm) in the NWB cohort and 0.3 mm (95 % CI, 0-0.7 mm) in the WBAT cohort (P = 0.10). In our survivorship analysis, we noted no deaths in the WBAT cohort compared to 17 % mortality in the NWB cohort at the one-year timepoint. CONCLUSION: Allowing patients to weight bear immediately after revision does not increase stem subsidence. Further studies are needed to determine whether early weightbearing provides a mortality benefit.

Four-Year Outcomes of Cementless Versus Cemented Fixation of a Newly Introduced Total Knee Arthroplasty Design.

BACKGROUND: Aseptic loosening continues to be a major cause of failure of total knee arthroplasty (TKA). Although cemented fixation remains the gold standard, there is renewed interest in cementless fixation as a means of decreasing this risk via biologic fixation. The purpose of this study was to evaluate the clinical outcomes of cemented and cementless versions of a newly introduced TKA design at an average of 4 years postoperatively. MATERIALS AND METHODS: This was a retrospective case-control study of 100 primary TKAs comparing cementless vs cemented TKAs using the same cruciate-retaining implant design (ATTUNE Knee System; DePuy Synthes). Fifty patients undergoing cementless TKA with a mean age of 60.8 years (range, 48-71 years) and body mass index (BMI) of 31.6 kg/m2 (range, 23.7-41.9 kg/m2) were matched to 50 patients undergoing primary cemented TKA with a mean age of 62.7 years (range, 51-73 years) and BMI of 30.1 kg/m2 (range, 24.6-43.9 kg/m2). The mean follow-up was 4.2 years (range, 4.0-4.4 years) in the cementless group and 7.6 years (range, 7.5-7.7 years) in the cemented group. Complications, clinical outcomes using the Knee Society Score (KSS), and radiographic analyses were evaluated at final follow-up. Student's t tests were used for statistical analyses. RESULTS: There was no statistical difference in age, BMI, and preoperative KSS between the two groups (P=.12, P=.15, and P=.55, respectively). There were no complications or reoperations in either cohort. There were no statistical differences in range of motion and total KSS at final follow-up between the two groups. Final total KSS had a mean of 91.1 for the cementless group and 93.7 for the cemented group. There was no radiographic evidence of component subsidence or loosening in either cohort. CONCLUSION: When compared with its cemented counterpart, the newly introduced cementless TKA design had similar excellent clinical improvements and radiologic results at an average of 4 years of follow-up. [Orthopedics. 2024;47(3):161-166.].

Machine Learning Models Based on a National-Scale Cohort Identify Patients at High Risk for Prolonged Lengths of Stay Following Primary Total Hip Arthroplasty.

BACKGROUND: Existing machine learning models that predicted prolonged lengths of stay (LOS) following primary total hip arthroplasty (THA) were limited by the small training volume and exclusion of important patient factors. This study aimed to develop machine learning models using a national-scale data set and examine their performance in predicting prolonged LOS following THA. METHODS: A total of 246,265 THAs were analyzed from a large database. Prolonged LOS was defined as exceeding the 75th percentile of all LOSs in the cohort. Candidate predictors of prolonged LOS were selected by recursive feature elimination and used to construct four machine learning models-artificial neural network, random forest, histogram-based gradient boosting, and k-nearest neighbor. The model performance was assessed by discrimination, calibration, and utility. RESULTS: All models exhibited excellent performance in discrimination (area under the receiver operating characteristic curve [AUC] = 0.72 to 0.74) and calibration (slope: 0.83 to 1.18, intercept: -0.01 to 0.11, Brier score: 0.185 to 0.192) during both training and testing sessions. The artificial neural network was the best performer with an AUC of 0.73, calibration slope of 0.99, calibration intercept of -0.01, and Brier score of 0.185. All models showed great utility by producing higher net benefits than the default treatment strategies in the decision curve analyses. Age, laboratory tests, and surgical variables were the strongest predictors of prolonged LOS. CONCLUSION: The excellent prediction performance of machine learning models demonstrated their capacity to identify patients prone to prolonged LOS. Many factors contributing to prolonged LOS can be optimized to minimize hospital stay for high-risk patients.

Poor Patient Follow-up After Metal-on-Metal Total Hip Arthroplasty.

Routine follow-up approximately every 2 to 5 years after total hip arthroplasty (THA) is a common practice. However, although patients are informed of the importance of follow-up, our mean follow-up rate for patients after standard non-metal-on-metal (MOM) THA is only 19%. The US Food and Drug Administration has released several statements on the importance of follow-up every 2 years after MOM THA. With the potential risks of MOM THA apparently widely known, we report on our ability to obtain timely follow-up at 2 separate centers. Two separate centers performed 570 MOM THA procedures between 2002 and 2010. An attempt was made to reach every patient by either telephone or letter to obtain ion levels, radiographs, and examinations. Repeat telephone calls and/or letters to those not reached were made annually. Patients were told of the unique importance of follow-up at each contact. Of the patients, 43% had not been seen within the past 5 years, and only 26% had been seen within the past 2 years. Only 61% had their first measurement of ion levels, and only 30% of patients had a second set of measurement of ion levels. A total of 48 revisions occurred in this group, and 36 patients died. Despite the apparent widespread dissemination of information regarding the potential risks of MOM THA and concerted efforts to contact patients for follow-up, we have been able to achieve a follow-up rate of only 26%. This rate is only marginally better than the mean follow-up for non-MOM THA in our practices. The implications of this poor follow-up are unknown. [Orthopedics. 2022;45(4):e196-e200.].

Bilateral Extensor Mechanism Allograft Reconstruction in Native Knees: A Case Report.

CASE: A 66-year-old man presented with chronic bilateral extensor mechanism dysfunction and profound patella baja after failed revision surgery for bilateral quadriceps tendon ruptures. Staged bilateral reconstruction with complete extensor mechanism allograft resulted in excellent two-year satisfaction and clinical outcomes. CONCLUSION: Complete extensor mechanism reconstruction can be a successful treatment for chronic quadriceps tendon rupture with profound patella baja.

Machine learning models accurately predict recurrent infection following revision total knee arthroplasty for periprosthetic joint infection.

PURPOSE: This study aimed to develop and validate machine-learning models for the prediction of recurrent infection in patients following revision total knee arthroplasty for periprosthetic joint infection. METHODS: A total of 618 consecutive patients underwent revision total knee arthroplasty for periprosthetic joint infection. The patient cohort included 165 patients with confirmed recurrent periprosthetic joint infection (PJI). Potential risk factors including patient demographics and surgical characteristics served as input to three machine-learning models which were developed to predict recurrent periprosthetic joint. The machine-learning models were assessed by discrimination, calibration and decision curve analysis. RESULTS: The factors most significantly associated with recurrent PJI in patients following revision total knee arthroplasty for PJI included irrigation and debridement with/without modular component exchange (p < 0.001), > 4 prior open surgeries (p < 0.001), metastatic disease (p < 0.001), drug abuse (p < 0.001), HIV/AIDS (p < 0.01), presence of Enterococcus species (p < 0.01) and obesity (p < 0.01). The machine-learning models all achieved excellent performance across discrimination (AUC range 0.81-0.84). CONCLUSION: This study developed three machine-learning models for the prediction of recurrent infections in patients following revision total knee arthroplasty for periprosthetic joint infection. The strongest predictors were previous irrigation and debridement with or without modular component exchange and prior open surgeries. The study findings show excellent model performance, highlighting the potential of these computational tools in quantifying increased risks of recurrent PJI to optimize patient outcomes. LEVEL OF EVIDENCE: IV.

Open Ankle Fractures: What Predicts Infection? A Multicenter Study.

OBJECTIVE: To identify the patient, injury, and treatment factors associated with an acute infection during the treatment of open ankle fractures in a large multicenter retrospective review. To evaluate the effect of infectious complications on the rates of nonunion, malunion, and loss of reduction. DESIGN: Multicenter retrospective review. SETTING: Sixteen trauma centers. PATIENTS: One thousand and 3 consecutive skeletally mature patients (514 men and 489 women) with open ankle fractures. MAIN OUTCOME MEASURES: Fracture-related infection (FRI) in open ankle fractures. RESULTS: The charts of 1003 consecutive patients were reviewed, and 712 patients (357 women and 355 men) had at least 12 weeks of clinical follow-up. Their average age was 50 years (range 16-96), and average BMI was 31; they sustained OTA/AO types 44A (12%), 44B (58%), and 44C (30%) open ankle fractures. The rate FRI rate was 15%. A multivariable regression analysis identified male sex, diabetes, smoking, immunosuppressant use, time to wound closure, and wound location as independent risk factors for infection. There were 77 cases of malunion, nonunion, loss of reduction, and/or implant failure; FRI was associated with higher rates of these complications (P = 0.01). CONCLUSIONS: Several patient, injury, and surgical factors were associated with FRI in the treatment of open ankle fractures. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Average narcotic usage in a group of TKA patients following a modern TKA protocol.

INTRODUCTION: The optimal dosing of post-operative total knee arthroplasty (TKA) narcotics is unclear. We report on the average narcotic usage in a group of patients treated with an identical multimodal pain protocol following TKA. MATERIALS AND METHODS: 49 patients undergoing TKA participated in the survey. Patients with pre-op narcotic use, recent prior total joint arthroplasty or study refusal were excluded. All patients received a spinal anesthetic. No pre-surgery narcotics were given. All received an identical local infiltrative anesthetic combination along with a multimodal pain protocol. Patients were placed into an identical rapid rehab program. Narcotic usage during hospitalization was recorded in morphine equivalent doses (MED). Patients were given a journal to record their daily narcotic utilization. RESULTS: Pre-operative pain scores of the excluded groups had slightly higher but clinically insignificant differences compared to the study group. In the hospital, POD1 study group daily MED averaged 28 (range 0-110). POD2 had an average of 33.6 and POD 3 daily usages averaged 28.6 (range 0-100). By the end of week two, the average daily use was 19.2 and 24% patients were off all narcotics. By the end of week four, the average daily usage was 7.5 and 63% of patients were off all narcotics. By 8 weeks, there were no patients still taking narcotics. KSS averaged 76.9 (range 51-97) at the 6 week visit, and 94.2 at the 3-month visit (range 72-100). SUMMARY: This study documents the average needs of an average TKA patient treated with modern pain protocols. The majority of these patients were off narcotics by week four.

The Natural History of Radiolucencies Following Uncemented Total Knee Arthroplasty at 9 Years.

BACKGROUND: Aseptic loosening remains a common cause of failure in total knee arthroplasty (TKA). There is an increased interest in using uncemented TKA to reduce this complication. Radiolucencies (RLs) following uncemented TKA can be concerning. We report on the 9-year history of RLs in patients with uncemented TKA. METHODS: Twenty-one patients (26 knees) were treated with a cruciate-retaining fully porous coated femur/tibia and cemented patella. At final follow-up, 17 patients (22 knees) were available for review. Average follow-up was 9.6 years, average age was 59.1, and average body mass index was 34.1. X-rays were taken at 6 weeks, 1 year, and at final follow-up. RLs were measured using the Knee Society scoring system and read by two separate surgeons. RESULTS: At 6 weeks, we identified RL in all patients on both the tibia and femur. The majority were beneath the tibial tray and femoral chamfer. At 1 year, 4 femurs and 4 tibias showed new RLs (<2 mm) in similar zones. Eighteen femurs and 18 tibias showed fewer or no change in RLs. At final follow-up, no new tibia or femur developed a new RL. In total, 9 of the 22 tibias and 17 of the 22 femurs had remaining RLs, all less than 2 mm and none were progressive or new. Knee Society Score averaged 92.5 (6 weeks), 95.1 (1 year), and 97.3 (final). CONCLUSION: RLs are common following uncemented TKA. Many resolve by 1 year. There does not appear to be any association between the presence of RLs and long-term follow-up function in this group of patients.