[Proximal femoral varus osteotomy in Legg-Calve-Perthes disease]

The proximal femoral varus osteotomy (FVO) aims to re-centre the femoral head in the acetabular socket after prognostically unfavourable subluxation, e.g. in Legg-Calve-Perthes disease (LCPD).

No unified indication criteria have been defined yet for containment therapy in LCPD. However, specific radiographic features related to deformity development, age at diagnosis or onset and classifications describing pathomorphological changes in the femoral head related to bone necrosis can support decisionmaking.

Absolute contraindications-a hinge abducted joint; failure of femoral head reduction in the 20° abduction anteroposterior view; total epiphyseal necrosis. Relative contraindication-children < 6 years, in lateral pillar classification group A or Catteral group I and II.

Lateral approach to the proximal femur. Insertion of the first K‑wire to mark the anteversion of the femoral neck. Additional K‑wires are placed parallel to the first via the positioner aiming block. Lokalise the optimal postion for the osteotomy. Insertion of additional K‑wires in the distal fragment an facilitate manipulation and serve as reference for derotation. After osteotomy proximal fixation of the plate with locking screws replacing the K-wires. Insertion of a cortical screw into the middle hole to achieve optimal interfragmentary compression. Remaining locking screws are inserted and cortical screw replaced by a locking screw.

Mobilization with heel-touch weight-bearing on crutches for 6 weeks. Increased weightbearing after radiographic follow-up as soon as sufficient bone union is present. Implant removal after 9-12 months. Return to sports after 3 months.

The FVO has been used in the surgical treatment of severe LCPD for nearly 60 years and is established worldwide. Growing knowledge and consecutive optimization of the surgery indication together with the new implants contribute to improving clinical and radiological outcomes and reducing intraoperative and postoperative complications.