Correction of Tetratorsional Malalignment of the Lower Extremities Improves Patient-Reported Outcomes

Abstract

Axial malalignment of the bilateral femurs and tibias, previously known as “miserable” malalignment, now renamed tetratorsional malalignment (TTM), presents with hip and/or knee pain refractory to nonoperative treatment. We sought to investigate whether bilateral rotational osteotomy of the femur and tibia leads to improvement in a deformity-specific patient-reported outcome measure (PROM). A retrospective review of patients who underwent staged rotational correction of the bilateral femur and tibias was performed. Computed tomography (CT) was used to measure the preoperative rotational profile and plan the surgical correction. Stabilization was predominantly with intramedullary nails. The primary outcome measure was the Limb Deformity-modified Scoliosis Research Society (LDSRS) score. Secondary outcomes included change in mechanical limb alignment and complications of the procedure. Sixteen patients (13 female and 3 male) with average age of 23.1 years (range: 15–36 years) underwent 4-segment rotational correction. The averages for femoral and tibial deformity correction were 23.5° (6.2° SD) and 20.9° (5.2° SD), respectively. The total LDSRS score improved from 3.67 (0.3 SD) to 4.39 (0.3 SD) ( P = .001). The LDSRS sub-scores for function, pain, and self-image also significantly improved. In patients not undergoing concurrent coronal deformity correction, the limb mechanical axis was not significantly changed. No additional procedures were performed to obtain bone union. Three patients required peroneal nerve decompression following the index procedure, and all neurologic symptoms resolved. This retrospective review suggests that correction of TTM of the lower extremities may lead to improvements in function, pain, and self-image. There were minimal complications and no iatrogenic deformity among 16 patients reviewed. The new diagnosis, TTM, is descriptive of this debilitating condition without communicating a negative patient image.