Validation of Single-Outcome Questionnaire in Primary TKA and THA

Patient-reported outcome measures can be used to evaluate post-operative health care quality and patient satisfaction. The Patient's Joint Perception (PJP) question gathers a single patient-reported outcome to measure how patients appraise their joint. This study compares PJP to the Forgotten Joint Score (FJS) at 21 months post-operation to assess its value.

A retrospective review was performed at an orthopedic specialty hospital for patients who completed both PJP and FJS questionnaires in 2020-2021 and underwent either a unilateral elective primary Total Knee Arthroplasty (TKA) or Total Hip Arthroplasty (THA). Spearman's correlation coefficients and P-values were calculated to determine external validity of PJP. Floor and ceiling effects were analyzed and considered present if ≥ 15% of patients achieved the worst or best score (0-4 for PJP and 0-100 for FJS).

In total, 534 patients (327 THA and 207 TKA) were surveyed at 21 months post-operation. External validity against FJS was assessed for both TKA (r = 0.66, P < .01) and THA (r = 0.69, P < .01). For TKA, the floor and ceiling effects were 0.97% and 25.12% for PJP and 3.86% and 4.83% for FJS, respectively. For THA, the floor and ceiling effects were 0.92% and 50.46% for PJP and 2.47% and 20.50% for FJS, respectively.

The PJP was correlated with FJS moderately for both TKA and THA and can be collected with lesser burden. However, ceiling effects were higher in both TKA and THA for PJP compared to FJS. Further studies are needed to investigate the questionnaires at additional time points and to evaluate the implications of high ceiling effects.