We, and others, have used OUKA for the revision of knees with persistent symptoms after valgus osteotomy of the upper tibia, although there have been few reports on the outcome.
Thornhill and Scott (1989), using the Brigham implant, referred to some successes but noted technical problems with ligamentous instability.
Vorlat et al. (2000) reviewed 38 medial OUKAs, of which six were performed on knees with failed high tibial osteotomy (HTO). Two of these had to be revised because of progression of arthritis in the lateral compartment. The failure rate of 33% in the HTO group was compared with a 6.3% failure rate in the group with primary OA.
Rees et al. (2001) collected data (from three sources) on 631 OUKAs, 18 of which had been performed for failed HTO and the remainder for primary anteromedial OA. The reason for revision of the original HTO was persistent medial pain in every case, and in all but one there had been undercorrection of the varus deformity. The mean cumulative follow-up times of the the failed HTO and primary AMOA groups were similar (5.6 years and 5.4 years, respectively) and there were no significant differences between their mean ages or sex ratios. The mean time to revision was 2.9 years for the HTO group (five knees) and 4.1 years for the primary OA group (19 knees). The cumulative survival rates at 10 years were 66 % and 96 %, respectively (log rank comparison P < 0.0001). The reason for all the OUKA failures in the HTO group was persistent pain and accelerated lateral wear. The explanation for this mode of failure may be biomechanical. OUKA corrects the varus deformity intra-articularly. If the varus has already been corrected (even partially) by an extra-articular osteotomy, valgus alignment may result, with overloading of the lateral compartment. The failure rate was independent of the type of osteotomy.
We believe that previous tibial osteotomy is a contraindication to OUKA. The revision rate of 34 % at a mean follow-up of 5.4 years is much worse than the results reported for TKA after HTO by Meding et al. (2000). They reported one implant failure in 33 knees followed for a mean of 8.7 years after TKA revision of failed tibial osteotomies.
Valenzuela et al. (2013) compared clinical and radiological outcomes between UKA after HTO (n=22); TKA after HTO (n=18); and primary UKA (n=22). OKS, AKSS, hip/knee/ankle angles, mechanical axis and patella height were evaluated pre- and postoperatively. At a mean of 64 months (range 19 – 180) postoperatively, the mean OKS were 43.8, 43.3 and 42.5 respectively (p=0.73) with similar AKSS-O and AKSS-F. The authors’ conclusion, which was different to ours, was that UKA can be safely performed after HTO. There may therefore be a role for OUKA after failed HTO. However, the indications for this are unclear so we still do not recommend it.
