A clinical risk score enables early prediction of dissatisfaction 1 year after total knee arthroplasty.

PURPOSE

Dissatisfaction after total knee arthroplasty (TKA) is a prevalent and clinically relevant problem that affects approximately 10%-20% of patients. The aim of this study is to identify factors associated with dissatisfaction 1 year after TKA.

METHODS

A total of 236 patients undergoing TKA were included in this prospective cohort study. Demographic data, preoperative clinical parameters (e.g., axial alignment, osteoarthritis severity) and patient-reported outcome measures (PROMs) were collected preoperatively, at 1 month and 1 year after TKA, encompassing the Knee Society Score (KSS) and Knee injury and Osteoarthritis Outcome Score (KOOS). The primary outcome was dissatisfaction 1 year after TKA, defined as ≤20 points on the KSS satisfaction scale. A risk score based on multiple regression and area under the curve (AUC) analyses was calculated to predict dissatisfaction.

RESULTS

One year after TKA, 16% of the patients were dissatisfied. Dissatisfied patients were significantly younger (p = 0.023) and had a higher body mass index (BMI) (p = 0.007). No differences were observed in preoperative objective (p = 0.903) and functional KSS (p = 0.346), pain (p = 0.306), osteoarthritis severity (p = 0.358), axial knee alignment (p = 0.984) or psychological distress (p = 0.138). The likelihood of dissatisfaction at 1 year was 3.0, 4.0, 7.4, 4.3 and 2.8 times higher amongst patients aged <63.5 years, with a BMI > 30.1 kg/m, a KOOS < 50%, a KSS < 42 points and a KSS < 9 points (all at 1 month), respectively. Using these variables, a risk score with a maximum of 7 points was developed, demonstrating a high predictive value for dissatisfaction (AUC: 0.792 [95% confidence interval: 0.700-0.884], p < 0.001).

CONCLUSION

Dissatisfaction 1 year after TKA can be predicted by a weighted risk score that includes patient age, BMI, pain, subjective functionality and unmet expectation 1 month postoperatively. Using the risk score, early detection of dissatisfaction has the potential to enable targeted interventions and improve patients' quality of life.

LEVEL OF EVIDENCE

Level II, Prognostic study.