FUNCTIONAL OUTCOME OF PRIMARY VERSUS REVISION TOTAL HIP ARTHROPLASTY- A CASE MATCHED STUDY

Abstract

Information on the complication rates of revision THA is well documented. However, there is little data on functional outcome of revision THA. We aimed to determine the functional outcome of revision THA (n=72 subjects) versus individually matched THA controls. All subjects underwent THA for idiopathic osteoarthritis, and the same investigator made all clinical assessments. The mean ages (±SD) at primary THA were 61.3±7.2 years (THA revisions) and 61.1±7.4 years (THA controls). The male: female ratio was 36:36 in both groups. The groups were also individually matched for primary THA year (median 1984), presence of bilateral THA (43 subjects per group), and total follow up time (mean 14±4 years). Revision-free survival in the THA revision group was 9.8±3.9 years, and post revision follow up was 4.5±3.0 years.

Sixteen subjects had revision of 1 implant component and 56 had both revised. Allograft was required in 25 and 17 of the cup and stem revisions, respectively. The median (Interquartile range) Oxford and Harris Hip Scores in the revision and control groups were 28 (21 to 39) and 72 (60 to 86) versus 21 (16 to 32) and 89 (79 to 97), respectively (Wilcoxon, P< 0.001 both comparisons). The largest difference in Harris Hip Score was found in the function domain; revision THA median score 24 (17 to 36) versus 38 (28 to 44) in the controls (P< 0.001). Male subjects had slightly better outcomes versus females in both groups (P< 0.05). Revision of both versus 1 component, bilateral THA, age at revision, and use of allograft did not affect outcome (P> 0.05 all comparisons).

The clinical outcome of revision hip arthroplasty for aseptic loosening is worse than that of primary arthroplasty, principally in terms of function. However, use of allograft, number of components revised, and age at revision are not strongly associated with clinical outcome of revision surgery.