Minimal clinically important differences in health-related quality of life after total hip or knee replacement: A systematic review

Abstract

Objectives: We aimed first to summarise minimal clinically important differences (MCIDs) after total hip (THR) or knee replacement (TKR) in health-related quality of life (HRQoL), measured using the Short-Form 36 (SF-36). Secondly, we aimed to improve the precision of MCID estimates by means of meta-analysis.

Methods: We conducted a systematic review of English and non-English articles using MEDLINE, the Cochrane Controlled Trials Register (1960-2011), EMBASE (1991-2011), Web of Science, Academic Search Premier and Science Direct. Bibliographies of included studies were searched in order to find additional studies. Search terms included MCID or minimal clinically important change, THR or TKR and Short-Form 36. We included longitudinal studies that estimated MCID of SF-36 after THR or TKR.

Results: THREE STUDIES MET OUR INCLUSION CRITERIA, DESCRIBING A DISTINCT STUDY POPULATION: primary THR, primary TKR and revision THR. No synthesis of study results can be given.

Conclusions: Although we found MCIDs in HRQoL after THR or TKR have limited precision and are not validated using external criteria, these are still the best known estimates of MCIDs in HRQoL after THR and TKR to date. We therefore advise these MCIDs to be used as absolute thresholds, but with caution.

Keywords: Health-related quality of life; Minimal clinically important differences; SF-36; Systematic review; Total hip replacement; Total knee replacement.

Fig. 1

Flow-chart of study inclusion (THR, total hip replacement; TKR, total knee replacement; MCID, minimal clinically important difference).

Fig. 2

Graph showing the minimal clinically important differences (MCIDs) in the domains of the Short-Form 36 (SF-36) at six months after primary total hip (THR) and total knee replacement (TKR) and revision THR. The size of the coloured circles represents the sample sizes used to estimate the MCID, and the error bars denote the 95% confidence intervals (PF, physical functioning; RP, role physical; BP, bodily pain; GH, general health; VT, vitality; SF, social functioning; RE, role emotional; MH, mental health).

Fig. 3

Graph showing the minimal clinically important differences (MCIDs) in the domains of the Short-Form 36 (SF-36) at two years after primary total hip (THR) and total knee replacement (TKR). The size of the coloured circles represents the sample sizes used to estimate the MCID, and the error bars denote the 95% confidence intervals (PF, physical functioning; RP, role physical; BP, bodily pain; GH, general health; VT, vitality; SF, social functioning; RE, role emotional; MH, mental health).