Risk Calculators Predict Failures of Knee and Hip Arthroplasties: Findings from a Large Health Maintenance Organization

Abstract

Background Considering the cost and risk associated with revision Total knee arthroplasty (TKAs) and Total hip arthroplasty (THAs), steps to prevent these operations will help patients and reduce healthcare costs. Revision risk calculators for patients may reduce revision surgery by supporting clinical decision-making at the point of care. Questions/purposes We sought to develop a TKA and THA revision risk calculator using data from a large health-maintenance organization's arthroplasty registry and determine the best set of predictors for the revision risk calculator. Methods Revision risk calculators for THAs and TKAs were developed using a patient cohort from a total joint replacement registry and data from a large US integrated healthcare system. The cohort included all patients who had primary procedures performed in our healthcare system between April 2001 and July 2008 and were followed until January 2014 (TKAs, n = 41,750; THAs, n = 22,721), During the study period, 9% of patients (TKA = 3066/ 34,686; THA=1898/20,285) were lost to followup and 7% died (TKA= 2350/41,750; THA=1419/20,285). The outcome of interest was revision surgery and was defined as replacement of any component for any reason within 5 years postoperatively. Candidate predictors for the revision risk calculator were limited to preoperative patient demographics, comorbidities, and procedure diagnoses. Logistic regression models were used to identify predictors and the Hosmer-Lemeshow goodness-of-fit test and c-statistic were used to choose final models for the revision risk calculator.

Can patient-reported outcomes predict re-operations after total hip replacement?

“…In a systematic review by Prokopetz et al [13] including 65 articles investigated with revision following THR for any reason as outcome, age (40%) and sex (28%) were the most common variables associated with predicting risk of future revision. This is also supported by later reports Categorical data presented as n (%) and continuous data as mean (standard deviation) for sex [11,13] and age [10][11][12][13]. In our study we also present an association with a higher risk of re-operation for younger patients and males, but these factors are weaker than postoperative PROMs to predict the risk of a late re-operation.…”

“…Factors other than PROMs have been previously reported [10][11][12][13] as contributing to the risk of re-operation, such as high BMI and long surgery time. We have not taken all of these confounders into consideration in our model, which is a limitation that needs to be given attention when interpreting results.…”

“…We have also selected our patients in order to reduce confounding biases and provide a homogenous group to investigate. The previously described studies presenting patient-related factors [10][11][12][13] and PROMs [14][15][16] to predict the risk of future revision following THR used OR (odds ratio) and HR (hazard ration) to predict the risk of revision. But these methods have been declared unsuitable for such conclusions since they lack predictive strength [25].…”

“…There are several reports presenting risk factors for revision following THR, including patient-related factors [10][11][12][13], and implant and surgical procedure-related factors [12,13], as well as PROMs-related factors such as the Harris Hip [14] and Oxford Hip scores [15,16]. To our knowledge there are no reports using time-dependent area under the curve values (AUC-values)/concordance indices (C).…”

Revision for prosthetic joint infection following hip arthroplasty

“…The trend for increased risk of early revision for hip PJI is likely to be multifactorial. Factors may include the increased accuracy of tests available to clinicians for the diagnosis of PJI, 25 and the increased risk factors for PJI among the population undergoing hip arthroplasty such as elevated body mass index 26 and increased bed occupancy. 27 It may also represent a progression towards earlier recognition and/or treatment in specialist centres with a subsequent benefit in terms of reduced long-term PJI.…”