How Do Disease-specific and General-health PROMs Change over 15 Years after TKA?

All PROMs improved within 6 months; disease-specific outcomes were generally stable through 5 years.

Participants and Methods

1,264 patients, mean age 68.5 years and 93.7% women, underwent primary TKA in 2005–2013 and completed baseline/10-year assessments. A prospective registry was analyzed retrospectively using KSS, WOMAC and SF-36 at baseline, 6 months and 1, 2, 5, 10 and 15 years, with GLM and linear mixed-effects models.

The order in which you read the painting.

Mean KSS and WOMAC trajectories from before surgery to 15 years. Read them together with the number assessed at each time point and the 95% confidence intervals. Distinguish early improvement at 6 months, stability during years 1–5 and later functional changes. A small statistical difference may not exceed MCID. This single-center registry included 10-year completers and excluded revisions; without nonsurgical controls, aging and TKA effects cannot be fully separated.

Main Findings

All PROMs improved within 6 months; disease-specific outcomes were broadly stable through 5 years. WOMAC pain/stiffness remained stable at 5–10 years; physical function declined slightly but significantly, below MCID. SF-36 physical/mental scores declined beyond MCID after 5 years. At 15 years, PROMs remained better than baseline, with age/sex-specific trajectories.

The point of reading on surgery

The findings can inform preoperative counseling and long-term rehabilitation research by distinguishing early improvement, long-term pain stability, and age-related functional decline.

Limitations

Therapeutic Level III. Selection was limited to survivors completing the 10-year assessment, with a predominance of women. Implants and alignment strategies were not directly compared.

Let's put it briefly.

What did this study confirm?

All PROMs improved within 6 months; disease-specific outcomes were generally stable through 5 years.

Can it be applied directly to individual patients' treatment decisions?

Therapeutic Level III. Selection was limited to survivors completing the 10-year assessment, with a predominance of women. Implants and alignment strategies were not directly compared.

Keywords

Arthroplasty, Replacement, Knee
Patient Reported Outcome Measures
Osteoarthritis, Knee
Retrospective Studies
Longitudinal Studies
Treatment Outcome
Aged, 80 and over
Time Factors

Abstract · Original text

Byung Sun Choi, Du Hyun Ro, Hyuk-Soo Han. Long-Term Trajectories of Patient-Reported Outcomes Following Total Knee Arthroplasty: A Longitudinal Study of 1,264 Patients. The Journal of bone and joint surgery. American volume. 2026;108(5):355-362. doi:10.2106/JBJS.25.00770.

BACKGROUND

Although total knee arthroplasty (TKA) is known to improve patient-reported outcome measure (PROM) scores in the short term to midterm, the long-term trajectories of both disease-specific and generic PROM scores remain unclear.

METHODS

We retrospectively analyzed the prospectively collected registry data of 1,264 patients (mean age, 68.5 years; 93.7% female) who underwent primary TKA for osteoarthritis between 2005 and 2013 and completed PROM assessments at baseline and 10 years postoperatively. Disease-specific PROMs were assessed using the Knee Society Knee Score (KSKS), Knee Society Function Score (KSFS), and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Generic PROMs were assessed using the Short Form-36 Health Survey (SF-36). Assessments were performed preoperatively and at 6 months and 1, 2, 5, 10, and 15 years postoperatively. Generalized linear models and linear mixed-effects models were used to evaluate temporal changes and subgroup differences by age and sex.

RESULTS

All PROM scores improved significantly within 6 months after TKA. Thereafter, disease-specific PROMs showed modest changes up to 1 year, with relative stability until 5 years, whereas generic PROMs demonstrated heterogeneous patterns across different domains. Between 5 and 10 years postoperatively, WOMAC pain and stiffness scores did not show significant changes, the KSKS decreased but not significantly so, and WOMAC physical function scores exhibited small but significant deterioration that was not clinically meaningful. SF-36 domains demonstrated varied trajectories: physical and mental component scores declined by more than the minimal clinically important difference after 5 years, whereas the social functioning score showed continuous improvement, although not all changes were significant. Octogenarians demonstrated lower physical functioning scores but higher social functioning scores in the long term compared with younger patients, and female patients demonstrated inferior functional and vitality scores compared with male patients.

CONCLUSIONS

Both disease-specific and generic PROM scores after TKA improved significantly and remained superior to baseline scores over a 15-year period, although physical function scores tended to decline in the long term. In this large, predominantly female Korean cohort, the distinct age- and sex-specific trajectories highlight the importance of implementing individualized, time-adapted long-term management strategies to optimize patient outcomes.

LEVEL OF EVIDENCE

Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Read abstract on PubMed Terms of use

The original paper.

Long-Term Trajectories of Patient-Reported Outcomes Following Total Knee Arthroplasty: A Longitudinal Study of 1,264 Patients

Byung Sun Choi, Du Hyun Ro, Hyuk-Soo Han
Journal of Bone and Joint Surgery American Volume · 2026 · online 2025

DOI · 10.2106/JBJS.25.00770 PubMed Based data

Reviewed academic journal articles