OUTCOME OF TOTAL KNEE ARTHROPLASTY FOR SEVERE VALGUS KNEES USING DEEP MEDIAL COLLATERAL LIGAMENT PRESERVATION TECHNIQUE

Background Total knee arthroplasty has been performed even for severe valgus knee. All ligaments around knee must be balanced to obtain good clinical results. Especially medial collateral ligament plays a role as a stabilizer. For severe valgus knee, however, deep medial collateral ligament (dMCL) located closely to the articulating tibial surface [Fig. 1] can be damaged by bone resection in standard tibial osteotomy which may leads to progress valgus deformity. Purpose There are no report of dMCL preserved total knee arthroplasty for sever valgus knee. Thus it was evaluated the clinical outcomes of total knee arthroplasty for severe valgus knees using dMCL preservation technique. Methods Twenty six knees of 18 osteoarthritis and 8 rheumatoid arthritis with severe valgus deformity (from 10° to 56°) underwent TKA between January 2006 and January 2014 was reviewed retrospectively. All surgeries were conducted by lateral parapatellar approach. Additional four mm resection was conducted on distal femur. Resection level at tibia was one to three mm below the medial joint line to preserve dMCL. GENESIS II PS with high flex insert (Smith and Nephew) was used for 25 knees. One knee with 56° valgus deformity that had no end point of MCL was required Rotating Hinge Prosthesis (Link). Mean follow up time was four years (range one to nine years). Results Mean Japanese Orthopaedic Association (JOA) score and femorotibial angle was improved from 53°±12.6 to 84°±7.6 and from 159°±9.3 preoperatively to 172.6°±2.3 postoperatively, respectively (both P 0.05). No patient had any postoperative complications including deep infection, peroneal palsy, loosening of the implant and pulmonary embolism. Every valgus knee underwent total knee arthroplasty using dMCL preservation technique had static end point of MCL at the last follow up. No progress of the valgus deformity was found and revision surgery for every case in this study. No potential COI to disclose.