title: Subtrochanteric osteotomy for femoral mal-torsion through a surgical dislocation approach.
abstract: Missed torsional femur deformities may contribute to reasons for failure after open and more likely arthroscopic hip preservation surgery. A number of surgical approaches have been described for addressing torsion abnormalities. This report describes a subtrochanteric osteotomy technique in a consecutive series of patients with complex hip pathologies, for which intertrochanteric osteotomy is not suitable and precise derotation is required. Subtrochanteric derotation was performed, always in combination with a surgical hip dislocation, in accordance with the authors' preferred technique. Before osteotomy, a localized decortication was executed. Application of a 4.5-mm broad or narrow plate was undertaken with dynamic compression of the osteotomy. Twenty-eight consecutive subtrochanteric derotational osteotomies were performed in 26 patients. Twenty-one females and five males were treated at an average age of 21.4 years (range, 12-43). Underlying diagnoses included dysplasia, arthrogryposis, cerebral palsy, Down's syndrome, instability and impingement. The decision to perform derotation was for antetorsion over 20° or less than 0° (retrotorsion). Patients were followed clinically and radiographically till final follow-up. All patients went on to successful osteotomy union. There were two initial failures: one delayed union prompting revision fixation in a chronic smoker and one plate failure due to self-accelerated weight-bearing in a patient status post successful contralateral derotational osteotomy. Rotational deformity of the femur must be considered in the patient undergoing hip preservation surgery. This technique of subtrochanteric derotational osteotomy, with adjunctive surgical hip dislocation, is applicable and reproducible in the setting of complex hip pathologies.
  
  
  METHODS
  IV, case series.
authors.affiliation: 1. Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: Atul F
authors.initials: AF
authors.lastname: Kamath
authors.affiliation: 2. University of Berne, Berne, Switzerland.
authors.forename: Reinhold
authors.initials: R
authors.lastname: Ganz
authors.affiliation: 3. Department of Orthopaedic Surgery, The 1st Affiliated Hospital of PLA General Hospital of CPLA, Beijing, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Zhang
authors.affiliation: 4. Santa Corona Hospital, Livio Sciutto Onlus Foundation for Orthopedic Biomedical Research, Via XXV Aprile, 38 17027, Pietra Ligure SV, Italy.
authors.forename: Guido
authors.initials: G
authors.lastname: Grappiolo
authors.affiliation: 5. Department of Orthopaedic Surgery, Schulthess Klinik, Zürich, Switzerland.
authors.forename: Michael
authors.initials: M
authors.lastname: Leunig