Abstract
The Repicci modification of the Marmor unicompartmental arthroplasty (UKA) has provided a minimally invasive alternative to proximal tibial osteotomy for localised osteoarthritis. Advantages of UKA include preservation of bone, faster rehabilitation and maintained function. This study analyses the survivorship of the Repicci medial compartment arthroplasty with a minimum 10-year follow-up.
438 medial UKR procedures were performed between 01/01/1998 and 01/07/2001 included 68 bilateral procedures in 370 patients. The patients comprised of 229 males and 141 females. A specific set of selection criteria were used, including clinical, radiological, an arthroscopic data. The average age at operation was 66.7 years. The average follow-up was 12.8 years. For the patients who are not reachable, we sought the help of the Australian joint replacement registry. All revisions were identified. Procedures were reviewed to determine survivorship and function. Clinical outcomes scores of SF36v2. WOMAC and Oxford Knee were analysed at pre-operative, 1, 3, 5 and 10 year intervals.
In 54 patients (64 procedures) the implant was in situ at the time of death. Revision was carried out in 37 knees (8.5%) at a mean time period of 7.8 years (1–13) post-operatively. Of the revisions, the commonest cause was progression of arthritic changes in the lateral compartment, 25 patients. Loosening of the tibial component was present in six patients and for six patients whose data was obtained from the registry, revision was documented, but no cause was identified. Kaplan-Meier investigation showed survivorship of 91.6% to 12.5 years. Average pre-operative, 1, 3, 5 and 10 years SF36v2 Total scores were 107.80, 124.57, 124.83, 111.14 and 121.47. WOMAC Total scores for pre-operative, 1, 3, 5 and 10 years were 51.96, 83.34, 80.59, 82.00 and 78.54. Oxford Knee scores for pre-operative, 1, 3, 5 and 10 years were 35.76, 20.99, 19.28, 19.61 and 21.16.
Significant differences (p<0.0001) were observed between all pre-operative and post-operative 1, 3, 5 and 10 year outcomes of SF36v2, WOMAC and Oxford Knee scores.
UKR is an operation which is often regarded as a temporising procedure, on the way to a total knee replacement, the attrition rate is less than 1% per year, indicates that long-term function is a goal which may be achievable.
UKR provides satisfactory function, with a low revision rate, and a minimally invasive approach does not decrease the efficacy, while currently, improving function, speed of recovery, and patient satisfaction. Patient selection, particularly in relation to the status of the lateral compartment articular surface may be an important aspect in minimising revision incidence.
