Abstract
Purpose
Primary total hip arthroplasty (THA) has been a very successful surgical intervention for the management of end-stage arthritis in geriatric patients (> age 65). The mid- to long-term results have been less satisfactory however, in younger patients primarily due to the wear of the acetabular liner and loosening of the femoral component.
The primary study purpose was to compare pain, function and stiffness over the first five years in a population less than 60 years of age who received either an alumina liner/alumina femoral head (alumina group) or a crossfire UHMWPE liner/alumina head (Poly group) following primary THA. Secondarily, we compared re-operation rates over five years between these two groups.
Method
This was a randomized, controlled clinical trial of subjects with non-inflammatory OA who were booked for primary THA and consented to participate in the study. Subjects were evaluated pre-operatively and again at one and five years post-operatively by an evaluator who was blinded to group allocation. At each assessment, subjects completed the WOMAC Osteoarthritis Index (WOMAC); complications and re-operations were also recorded. All analyses were performed on an intention to treat basis.
Results
92 subjects were enrolled in the study. The mean age of subjects was 52.4 (SD 6.8) and 50 (54%) were male and was similar between groups (p>0.10). Baseline pain, function and stiffness as measured by the WOMAC were also similar between groups (p>0.48). Five-year follow-up data was available for 78 (85%) patients. Both groups showed substantial improvement in pain, function and stiffness within one year that was maintained out to five years post-operatively; there were no statistically significant differences between groups (p>0.50). Four subjects required re-operation within five years; no re-operation was related to liner type two cases were dislocation due to the malposition of the cup while the remaining two re-operations occurred in the immediate post-operative period for removal of hematoma.
Conclusion
Our prospective randomized controlled trial showed substantial post-operative improvements in pain, stiffness, and function that were maintained out to five years, with no statistically significant differences seen between the two groups. No re-operations that were related to the liner type occurred in the first five post-operative years
