title: Adverse events and survival after closing- and opening-wedge high tibial osteotomy: a comparative study of 412 patients.
abstract: OBJECTIVE
  Varus medial knee osteoarthritis (OA) can be treated with a closing-wedge (CW) or opening-wedge (OW) high tibial osteotomy (HTO). Little is known about the adverse event (AE) rate of these techniques. The purpose of this study was to examine the AE rate and survival rate of a consecutive series of 412 patients undergoing CW- or OW-HTO.
  
  
  METHODS
  Medical records were retrospectively screened, and all patients who underwent HTO from 1993 to 2012 at the Erasmus University Medical Centre were assessed with a self-administered questionnaire. Patients filled in the intermittent and constant osteoarthritis pain score, knee injury and osteoarthritis outcome score, and a general questionnaire focusing on AE.
  
  
  RESULTS
  Medical records of 412 patients (354 CW- and 112 OW-HTOs) were screened. Of the 358 eligible patients, 291 (81 %) returned their questionnaire. A total of 80 AE (17 %) were found in 466 osteotomies. In the CW-group, 47 (13 %) serious adverse events (SAE) and 2 (0.6 %) AE were found. In the OW-group, 17 (15 %) SAE and 14 (13 %) AE were found. The most common AE was in 14 (4 %) patients of the CW-group sensory palsy of the common peroneal nerve. The most common AE in the OW-group was persistent pain at the iliac crest [11 (9.8 %) patients]. Hardware was removed in 48 % of the CW-osteotomies and 71 % of the OW-osteotomies (p < 0.05). The probability of survival was 75 % after 10 years in the CW-group versus 90 % in the OW-group (p < 0.05). In both groups, an equal number of patients were "in need for prosthesis" according to OARSI criteria.
  
  
  CONCLUSIONS
  OW-HTO was associated with more AE than CW-HTO. OW-HTO resulted in better survival than CW-HTO. However, in both groups an equal number of patients were in need for prosthesis.
  
  
  METHODS
  Retrospective comparative study, Level III.
authors.affiliation: Department of Orthopaedics, Erasmus University Medical Centre, PO Box 2040, 3000 CA, Rotterdam, The Netherlands. t.duivenvoorden@erasmusmc.nl.
authors.forename: T
authors.initials: T
authors.lastname: Duivenvoorden
authors.affiliation: Department of Orthopaedics, Erasmus University Medical Centre, PO Box 2040, 3000 CA, Rotterdam, The Netherlands.
authors.forename: P
authors.initials: P
authors.lastname: van Diggele
authors.affiliation: Department of Orthopaedics, Erasmus University Medical Centre, PO Box 2040, 3000 CA, Rotterdam, The Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: Reijman
authors.affiliation: Department of Orthopaedics, Erasmus University Medical Centre, PO Box 2040, 3000 CA, Rotterdam, The Netherlands.
authors.forename: P K
authors.initials: PK
authors.lastname: Bos
authors.affiliation: Department of Orthopaedics, Erasmus University Medical Centre, PO Box 2040, 3000 CA, Rotterdam, The Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: van Egmond
authors.affiliation: Department of Orthopaedics, Erasmus University Medical Centre, PO Box 2040, 3000 CA, Rotterdam, The Netherlands.|Department of General Practice, Erasmus University Medical Centre, Rotterdam, The Netherlands.
authors.forename: S M A
authors.initials: SMA
authors.lastname: Bierma-Zeinstra
authors.affiliation: Department of Orthopaedics, Erasmus University Medical Centre, PO Box 2040, 3000 CA, Rotterdam, The Netherlands.
authors.forename: J A N
authors.initials: JAN
authors.lastname: Verhaar
mesh_terms: D000328:Adult; D019645:Arthroplasty, Replacement, Knee; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000601:surgery*; D010027:Osteotomy / Q000009:adverse effects* / Q000379:methods; D010146:Pain / Q000209:etiology; D020427:Peroneal Neuropathies / Q000209:etiology; D011183:Postoperative Complications; D012189:Retrospective Studies; D011795:Surveys and Questionnaires; D013977:Tibia / Q000601:surgery*; D016896:Treatment Outcome
keywords: Adverse events; Closing-wedge high tibial osteotomy; Opening-wedge high tibial osteotomy; Survival