(Research Hub Theater) Preoperative Factors Determining Physical Disability After Total Knee Replacement

Background and/or Objectives: Knee osteoarthritis (KOA) is a chief cause of disability, particularly impacting activities of daily living (ADL). For people with advanced knee OA, Total Knee Arthroplasty (TKA) is often a preferred approach to management. The aim of this study is to identify baseline demographic and clinical characteristics that are associated with functional disability after TKA.

Design: Prospective clinical cohort study

Setting : Orthopedic Surgery Department of CHUSJ, Porto, Portugal. Department of PM&R, Northwestern University

Participants : A total of 94 knee OA patients scheduled for TKA.

Interventions: Not applicable.

Main Outcome Measures: Functional status and ADL disability measured by KOOS-ADL

Results: Knee OA patients’ demographic and clinical characteristics were measured before and 6 months after TKA. At 6 months, 84 KOA patients completed the study. The mean age was 65.98 (± 6.90) years and 76% were female.  We studied the effects of multiple baseline factors on KOOS-ADL including pain intensity, neuropathic pain score, anxiety, depression, pain catastrophizing and clinical parameters (age, sex, pain duration, Kellgren-Lawrence grade). A multivariable regression model was able to predict 30% of post-surgical ADL disability (Adj. R2 = 0.3, p=0.002). Statistically significant terms in our model were age (β=0.343, p=0.021), body mass index (BMI) (β=0.43, p=0.047) and neuropathic pain scale (DN4) (β=1.130, p=0.012). Importantly, when controlling for all other variables studied, pre-surgical ADL disability was not a statistically significant term, thus not an independent predictor of post-surgical ADL disability in our sample.

Conclusions: We were able to define clinical predictors accounting for 30% of post-TKA disability for ADL. Presurgical neuropathic pain score, age and BMI were the factors deemed significant in our predictive modelling. We believe preoperative risk assessment regarding these factors and adapting rehabilitation programs accordingly may be beneficial in improving functional outcomes.