[Torsional osteotomy : Operative treatment of patellofemoral maltracking]

Abstract

Background: Patellofemoral maltracking may congenitally be caused by excessive internal maltorsion of the femur and/or excessive external maltorsion of the tibia.

Objective: Pain relief, femoropatellar stability, well-balanced charge of femoral and patellar cartilage.

Indications: Anterior knee pain, patellar instability, associated with "inwardly pointing knee" syndrome.

Contraindications: Open physes, > 50 years, chronic/fixed patella luxation, congenital connective tissue and bone healing disorders.

Surgical technique: Analysis of leg geometry and patellofemoral anatomy. Knee arthroscopy. Supracondylar external torsional osteotomy of the femur: medial approach, ventral shift of vastus medialis muscle. Definition of osteotomy plane. Torsion control. Complete transversal osteotomy. Acute external torsional correction. Fixation with internal plate. Supratuberositary internal torsional osteotomy of the tibia: exposure of lateral tibial head, detachment of the tibialis anterior muscle. Partial chisel osteotomy of the proximal tibial tuberosity. Definition of supratuberositary osteotomy plane. Torsion control with Schanz screws. Bending of a DC plate (DCP). Complete transversal osteotomy. Acute internal torsional correction and fixation with prebent DCP. With internal torsional correction > 10°, decompression of the peroneal nerve and proximal tibialis anterior fasciotomy.

Postoperative management: Neurovascular and muscle function follow-up. On postsurgery day 1, drainage removal, x-ray control, mobilization. Partial weight bearing (20 kg) for 4 weeks with stepwise load increments. Active/passive exercises. Thromboprophylaxis.

Results: In 25 patients, 30 external torsional osteotomies of the supracondylar femur with 13.8° (5-26°); in 45 patients, 53 internal torsional osteotomies of the supratuberositary tibial head with an average 10.8° (5-18°). No persisting compartment syndrome or infection. One non-union healed after revision. One dysfunction of the peroneal nerve resolved with time. No subluxation or redislocation of the patella. Anterior knee pain decreased significantly in both groups.

Keywords: Femur; Knee joint; Pain; Patellar dislocation; Tibia; Torsional malalignment.