What predicts 36-item health survey version 2 after total hip arthroplasty.

OBJECTIVE

To identify the factors having the greatest effect on the Medical Outcomes Study 36-Item Short-Form Health Survey, version 2 (SF-36v2) score after total hip arthroplasty (THA).

DESIGN

Retrospective review.

SETTING

Private 150-bed hospital.

PARTICIPANTS

Patients (N=659) who underwent initial THA for osteoarthritis (OA) of the hip between April 2007 and January 2009. A total of 138 patients who fulfilled the inclusion criteria were seen at the first follow-up, while 108 patients were included in the second follow-up; all 30 patients excluded at the second follow-up underwent contralateral THA between follow-ups. The average time ± SD from surgery to first follow-up was 195.1±67.7 days, and that to second follow-up was 443.0±108.5 days. Patients' average age ± SD was 61.1±9.9 years at first follow-up and 61.3±10.3 years at second follow-up. Women accounted for 85.5% of patients at first follow-up and 85.2% at second follow-up.

INTERVENTIONS: Not applicable.

MAIN OUTCOME MEASURES: Eight subscales of the SF-36v2, age, sex, body mass index, complications, living alone, contralateral hip OA, range of hip joint motion, walking aids, and preoperative mental health (MH) values from the SF-36v2.

RESULTS

Canonical correlation analysis showed that contralateral hip OA had a major effect on the SF-36v2 score at the first follow-up. At the second follow-up, excluding the 30 patients who had undergone contralateral THA, physical function measured by the SF-36v2 was strongly affected by age, and other items were strongly affected by preoperative MH.

CONCLUSIONS

When using the SF-36v2 as an assessment scale after THA, adjustments should be made for contralateral hip OA. Moreover, age and preoperative MH should also be considered.