title: The effect of medial opening and lateral closing high tibial osteotomy on leg length.
abstract: BACKGROUND
  High tibial osteotomy (HTO) is a common treatment for medial compartment arthritis of the knee in younger, more active patients. An HTO also potentially affects leg length. Mathematical models predict that the osteotomy type (medial opening-wedge vs lateral closing-wedge) and the magnitude of the correction determine the change in leg length, but no in vivo studies have been published.
  
  
  OBJECTIVE
  This study was undertaken to quantify and compare leg-length change after opening-wedge and closing-wedge HTO.
  
  
  METHODS
  Cohort study; Level of evidence, 3.
  
  
  METHODS
  Thirty-two medial opening-wedge and 32 lateral closing-wedge HTOs were selected from patients treated at the authors' institution. Preoperative and postoperative coronal plane alignment and leg length were measured and surgical details were collected.
  
  
  RESULTS
  The 64 osteotomies were performed at an average age of 57 years. The mean opening wedge was 9.3 mm and the mean closing wedge was 8.0 mm. Mean knee alignment changed from 174° preoperatively to 183° postoperatively in both groups. In the medial opening-wedge group, entire leg length changed from 836.3 ± 63.5 mm to 841.8 ± 64.1 mm, an increase of 5.5 ± 4.4 mm (P < .0001). Tibia length changed from 368 ± 30.9 mm to 372.3 ± 31.2 mm, an increase of 4.3 ± 2.3 mm (P < .0001). In the lateral closing-wedge group, entire leg length changed from 840.6 ± 51.5 mm preoperatively to 837.9 ± 52.0 mm postoperatively, a decrease of 2.7 ± 4.0 mm (P = .0008). Tibia length changed from 365.1 ± 23.2 mm to 361 ± 22.9 mm, a decrease of 4.1 ± 2.9 mm (P < .0001). The difference in mean leg-length change between opening-wedge and closing-wedge osteotomies was 8.2 ± 5.9 mm (P < .0001).
  
  
  CONCLUSIONS
  Both medial opening-wedge and lateral closing-wedge HTO can result in significant leg-length change, but changes are generally less than mathematical models predict.
authors.affiliation: Department of Orthopaedic Surgery, Hôpital de la Croix-Rousse, Centre Albert Trillat, 103 Grande Rue de la Croix-Rousse, Lyon 69004, France. robert.magnussen@gmail.com
authors.forename: Robert A
authors.initials: RA
authors.lastname: Magnussen
authors.forename: Sébastien
authors.initials: S
authors.lastname: Lustig
authors.forename: Guillaume
authors.initials: G
authors.lastname: Demey
authors.forename: Philippe
authors.initials: P
authors.lastname: Neyret
authors.forename: Elvire
authors.initials: E
authors.lastname: Servien
mesh_terms: D000328:Adult; D000368:Aged; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007717:Knee / Q000601:surgery; D008297:Male; D008875:Middle Aged; D010027:Osteotomy / Q000379:methods*; D013977:Tibia / Q000601:surgery*