Abstract
Purpose: We analysed knee prostheses preserving the posterior cruciate ligament (or both cruciates) performed after tibial osteotomy. We determined outcome as a function of any tibial callus deformation created by the tibial osteotomy.
Material and methods: This retrospective study included a consecutive series of 56 knee prostheses with preservation of the posterior cruciate ligament (n=43) or both cruciate ligaments (n=13). The patients had undergone prior tibial osteotomy for valgisation (n=47) or varisation (n=9). Seven groups were defined as a function of the preoperative tibial angle prior to TKA. The angle were measured with telegonometry. Minimum follow-up was one year, mean follow-up 4.1±2.8 years.
Results: The tibial tuberosity was raised in 15 cases. If there was major valgus or rotation deformation, tibial osteotomy was associated with the prothesis (n=9). At last follow-up, the mean IKSg, IKSf and HSS scores were 81.5, 77.6, and 82.3 respectively. The mean femorotibial angle was 177.4±4.2°. The mean tibial angle was 87.8±3° and the mean femoral angle was 89.8±2°. Preoperative tibial deformation was not influenced by clinical results. In case of preoperative tibial deformation situated between 5° valgus and 5° varus, operation time, blood loss, and femoraotibial axis at last follow-up were not significantly different. To correct for tibial valgus greater than 7°, tibial osteotomy was associated with prosthesis implantation during the same operative time in six out of thirteen cases. For preoperative tibial varus greater than 5°, the femorotibial axis was less well corrected.
Discussion: These clinical results were comparable to those reported in other series with preservation or not of the posterior cruciate ligament. Correction of the femorotibial angle was less satisfactory than in certain series, but the deformation and the surgical history were among the most marked in the literature. Preservation of the posterior cruciate ligament (or both cruciates) appears to have increased the technical difficulties for upper tibia exposure and position of the tibia implant. For tibial callus with valgus greater than 7°, the prostheses cannot be expected to provide a solution alone and osteotomy should be associated. For tibial callus with 5° or more varus, the indication for associated tibial osteotomy merits discussion.
The abstracts were prepared by Docteur Jean Barthas. Correspondence should be addressed to him at Secrétariat de la Société S.O.F.C.O.T., 56 rue Boissonade, 75014 Paris.
