Quality Adjusted Life Years gained by Hip and Knee Replacement Surgery and its Aftercare

OBJECTIVE: To determine the lifetime QALYs gained by total joint arthroplasty (TJA) and assess the QALYs attributed to specific postoperative rehabilitation interventions.

DESIGN: Secondary analysis of two multicenter randomized controlled trials with 3-, 6-, 12-, and 24-month follow-up.

SETTING: Two university hospitals, two municipal hospitals, and one rural hospital.

PARTICIPANTS: 837 patients who underwent THA or TKA INTERVENTIONS: RCT A: 465 patients were randomly assigned to receive aquatic therapy (pool exercises aimed at training of proprioception, coordination, and strengthening) after 6 versus 14 days after THA or TKA.

RCT B: 362 patients were randomly assigned to either perform or not perform ergometer-cycling beginning two weeks after THA or TKA.

MAIN OUTCOME MEASURE: QALYs, based on the SF-6D (Short-Form, 6 Dimension) utility, measured at baseline and 3, 6, 12 and 24-months follow-up.

RESULTS: After hip (knee) arthroplasty, the lifetime QALYs increased by 2.35 (1.81) years in the non-ergometer group, and by 2.30 (1.60) years in the late aquatic-therapy group. By ergometer-cycling, 0.55 additional QALYs could be gained after hip and 0.10 after knee arthroplasty, while the additional QALYs attributed to early aquatic-therapy were 0.12 years after hip and 0.01 years after knee arthroplasty.

CONCLUSIONS: This analysis provides a sound estimate for the determination of the lifetime QALYs gained by THA and TKA. In addition, this analysis demonstrates that specific postoperative rehabilitation can result in an additional mean QALY gain of 0.55 years, which represents one fourth of the effect of surgery. Even if this was interpreted as a small effect at an individual level, it is important when extrapolated to all patients undergoing TJA. At a national level, these improvements appear to have a similar magnitude of QALY gain when compared to published data regarding medications to lower blood pressure in all persons with arterial hypertension.