Abstract
Objectives
The approach in total knee arthroplasty (TKA) with severe valgus deformity is controversial. The lateral parapatellar approach has been proposed for several years, but surgical technique of this approach was unusual and difficult. Therefore, we have consistently been selected medial parapatellar approach (MPP) for all cases. In this study, we investigated the short term results of TKA for severe valgus deformity with MPP about clinical and radiographic assessment.
Methods
Seven knees in seven cases of severe valgus knees with stand femorotibial angle (FTA) less than 160 degrees were enrolled. Osteoarthritis were 6 cases, hemophilic arthropathy was 1 case and no rheumatoid arthritis case. There were 6 female and 1 male, and mean age was 63.6 years (41–75 years). Duration of follow up ranged 3 months to 22.5 months, with mean of 10.9 months. We compared alignment on standing radiograph, range of motion (ROM), the Japanese Orthopaedic Association (the JOA) score for osteoarthritic knee pre/postoperatively, and examined post operative complication retrospectively.
Results
Significant changes of the range of motion pre- and postoperation were not obtained. The mean JOA score improved 50.0 preoperatively to 76.7 postoperatively. The mean stand FTA was corrected 149 degrees preoperatively to 174 degrees postoperatively (p0.001). Postoperative complications occurred in two cases. Aseptic loosening of tibial component due to pyoderma gangrenosum was one case, and peroneal nerve palsy was another. In the former case, revision TKA with varus-valgus constrained prosthesis were performed after a year from primary surgery. In the latter case, weakness of the extensor hallucis longus muscle was fully recovered 4 months later.
Conclusion
The medial parapatellar approach was beneficial for TKA of severe valgus knee over the short term.
