Soft Tissue Releases in Total Knee Arthroplasty for Valgus Deformities

Abstract Background Primary total knee arthroplasty (TKA) for valgus knee deformities can be challenging. Soft tissue releases are often necessary to achieve a well-balanced knee. We reviewed the frequency of soft tissue releases including lateral retinacular release (LRR) as it pertains to pre-operative limb alignment. Post-operatively, we evaluated limb alignment, knee range of motion (ROM), and complications. Methods From 2010 to 2016, 214 primary TKAs with valgus deformity were performed by a single surgeon. 181 patients had an average follow up of 24 months. For these patients, clinical data including pre- and post-operative ROM, complications, and revision rates were collected. Soft tissue releases, pre and post-operative limb axis deviation, and level of prosthetic constraint were recorded in all patients regardless of length of follow up. Results There were 33 knees (15%) that required 1 release, 69 knees (32%) required 2 releases, 81 knees (38%) required 3 releases, and 31 knees (14%) that required 4 or more releases. The average preoperative mechanical axis was 9.4°, and the average post-operative mechanical axis was 0.13°. There were 85 knees (40%) that required a LRR. Increased severity of pre-operative deformity correlated with the need for more soft tissue release, but did not correlate with the need for LRR. No knees were revised for instability. No patella complications resulted from LRR. Conclusion Selective soft tissue release for primary valgus TKA was effective without increasing prosthetic constraint. Severe deformities required more soft tissue releases. Lateral retinacular release can be frequently utilized with minimal complications.