Classifications of good versus poor outcome following knee arthroplasty should not be defined using arbitrary criteria

Abstract

A recently published paper by te Molder and colleagues in BMC Musculoskeletal Disorders confirmed prior reports indicating that definitions of good versus poor outcome cutoff scores for relevant knee arthroplasty outcomes including pain and function are heterogeneous and that this heterogeneity prevents generalizable inferences. In this Correspondence, we highlight an additional and, in our view, a more important problem with the substantial literature on this topic. There also is high homogeneity in that all studies relied on arbitrarily defined cutoff scores to differentiate good versus poor outcome. We discuss this problem and propose a method to avoid repeating the same problem in future studies designed to group patients into those with good versus those with poor outcome following knee arthroplasty.

Limitations of Minimal Clinically Important Difference Estimates and Potential Alternatives

“…Our concerns are centered on the methods utilized to calculate MCIDs. We have made similar arguments in prior publications 7-10 and elaborate on our concerns in the present review. Herein, we present the limitations of MCIDs that, in our opinion, justify why they should not be routinely utilized by orthopaedic surgeons.…”

A Latent Change Score Approach to Understanding Chronic Bodily Pain Outcomes Following Knee Arthroplasty

“…T he presence of multiple bodily pain sites in patients undergoing TKA is known to be a strong prognostic indicator of poor outcome 11,13,32 . Chronic widespread pain, a characteristic of nociplastic pain 33 , was relatively common in our TKA sample (43% at baseline) and likely results from maladaptive changes to the nervous system leading to heightened central nervous system pain sensitivity 34,35 .…”

CORR Insights®: Who Benefits From Hip Arthroplasty or Knee Arthroplasty? Preoperative Patient-reported Outcome Thresholds Predict Meaningful Improvement

“…One such methodology is the latent class analysis (LCA) used to differentiate good from poor outcome. Riddle et al [10] showed high discrimination between good and poor outcomes using the LCA methodology in a US-based total knee replacement cohort. They also have shown excellent reproducibility in a large total knee replacement cohort recruited in England [12].…”