Short-term results of the oxford unicompartmental knee replacement in patients less than sixty-five years of age

Our short-term results obtained with the Oxford unicompartmental knee prosthesis for unicompartmental knee arthrosis or AVN (avascular necrosis) in patients younger than 65 years of age are presented. Twenty patients (16 females and 4 males) with 20 prostheses were evaluated. The average age at surgery was 59 years (range 45 to 65 years). The etiology for surgery was osteoarthritis in 18 cases and AVN in two of them. Nineteen prostheses were uni-medial and one uni-lateral. After an average of 38 months, the mean Knee Society Score was excellent with 81.7 (range 29 to 100) points, the mean total WOMAC score was 26 (range 0 to 78), the mean reduced- WOMAC score 7.9 (range 0 to 24), the mean SF12 physical 36.8 (range 19.8 to 56.7), and the mean SF12 mental 47.5 (range 19 to 64). We did not find any significant correlation between the final outcome and the alignment of each component on X-ray. The only statistically significant correlation we could demonstrate was between the alignment of the knee on AP-View and the functional outcome. Three prostheses out of the twenty had to be revised, two of them due to early aseptic loosening of the tibial component and another one because of unexplained pain. Despite the relative high rate of early revisions (15%) in this group, our finding confirm the good results reported in different other studies regarding the success rate of unicompartmental knee replacement in patients under the age of 65 years.