Background: Little is known about factors that might predict
functional outcome following revision hip arthroplasty. The purpose of this
study was to identify predictors of pain and physical function at two years
following revision total hip arthroplasty and to evaluate whether the time
that the patient waited for the surgery and whether the patient had
complications were significant predictors of outcome.
Methods: One hundred and twenty-six patients (126 hips) were entered
prospectively into the study when their name was placed on the waiting list
for surgery. Baseline measures included demographic factors, comorbidities,
and the responses to the Short Form-36 (SF-36) and Western Ontario and
McMaster Universities Osteoarthritis (WOMAC) questionnaires. Follow-up was
carried out at six-month intervals while the patient was waiting for the
surgery; within one week prior to the surgery; and at six, twelve, and
twenty-four months after the surgery. Patient age and gender, the preoperative
WOMAC pain and function scores, the physical and mental component scores of
the SF-36, comorbidities, the number of revisions, bilateral joint
replacement, and the severity of the revision were evaluated as possible
predictors of ultimate pain and function as measured with the WOMAC
Results: The mean age of the patients was 68.6 years. Improvement in
WOMAC pain and function scores plateaued at six months. The mean pain score
(and standard deviation) improved from 9.4 ± 4.1 points preoperatively
to 3.9 ± 3.9 points at six months postoperatively, and the mean
function score improved from 35.4 ± 14.1 to 19.1 ± 13.2 points.
Preoperative pain (p = 0.002) and comorbidity (p = 0.02) were significant
predictors of pain at two years. There was a trend toward preoperative
function predicting function at twenty-four months (p = 0.07). There was no
significant deterioration in the WOMAC pain or function score while the
patients waited for surgery. Twenty-eight patients had complications. When the
time that the patient waited for the surgery and complications were added to
the models, only complications were found to be predictive of outcome (p =
0.04 for pain and p = 0.05 for function). Four patients required repeat
revision during the follow-up period.
Conclusions: Patients with better preoperative pain scores and fewer
comorbidities have better outcomes following revision total hip arthroplasty.
Although the time that the patient waited for the revision was not predictive
of the ultimate WOMAC pain and function scores, we believe that performing
revision arthroplasty before the patient has substantial functional compromise
potentially improves the outcome.
Level of Evidence: Prognostic Level I. See Instructions
to Authors for a complete description of levels of evidence.