Outcomes of lateral femoral sliding osteotomy in primary total knee arthroplasty for type two fixed valgus deformity.

PURPOSE

The aim of our study was to determine the surgical outcomes of patients who underwent lateral femoral sliding osteotomy (LFSO) with total knee arthroplasty (TKA) for Ranawat's type 2 fixed valgus deformity.

METHODS

The consecutive patients who underwent primary TKA with posterior-stabilized implant and LFSO for fixed valgus deformity were reviewed. The radiological parameters analyzed were pre- and postoperative hip-knee-ankle (HKA) angle and tibio-femoral angle in varus-valgus stress views. The clinical outcome was measured by Oxford knee score (OKS), knee society score (KSS), and functional score (KSS-F). The complications and any reoperation were noted in the follow-up.

RESULTS

There were total 28 patients included with an average follow-up time of 47.2 ± 24.9 months. The average arc of motion was 101.3 ± 23.8° preoperatively and 102.7 ± 11.8° postoperatively (p > 0.05). The average deformity in varus and valgus stress views was 196.6 ± 4.8 and 207.8 ± 7.4°, respectively. There was significant improvement in HKA from 205.2 ± 8.3° preoperatively to 181.9 ± 3.7° postoperatively (p < 0.05). At the final follow-up, bony union of the osteotomy fragment was noted in all the patients. There was significant improvement in OKS, KSS, and KSS-F score from a preoperative 15.1 ± 3.9, 35.1 ± 10.6, and 26.6 ± 12.6 to 40.3 ± 2.9, 85.6 ± 4.8, and 89.4 ± 7.7, postoperatively (p < 0.05), respectively. One patient had acute periprosthetic joint infection that was managed with debridement and polyethylene insert exchange.

CONCLUSION

Lateral femoral sliding osteotomy is an effective technique for optimal soft tissue balance in fixed valgus deformity. It provides satisfactory clinical outcome with restoration of knee alignment without using the constrained implants.