Soft Tissue Releases in Total Knee Arthroplasty for Valgus Deformities.

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 preoperative limb alignment. Postoperatively, we evaluated limb alignment, knee range of motion, and complications.
METHODS: From 2010 to 2016, 214 primary TKAs with valgus deformity were performed by a single surgeon. One hundred eighty-one patients had an average follow-up of 24 months. For these patients, clinical data including preoperative and postoperative range of motion, complications, and revision rates were collected. Soft tissue releases, preoperative and postoperative 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 postoperative mechanical axis was 0.13°. There were 85 knees (40%) that required an LRR. Increased severity of preoperative 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. LRR can be frequently used with minimal complications.