title: Radiological outcomes in a randomized trial comparing opening wedge and closing wedge techniques of high tibial osteotomy.
abstract: OBJECTIVE
  The aim of the present study was to examine changes in radiological variables in a prospective randomized study comparing opening wedge (OW) and closing wedge (CW) techniques of high tibial osteotomy (HTO). Our hypothesis was that there would be no differences in joint line angles or correction accuracy between the two groups, that patellar height would increase after CW HTO and decrease after OW HTO, and that leg length and posterior tibial slope would decrease after CW HTO and increase after OW HTO.
  
  
  METHODS
  Radiological data were collected from 70 patients participating in an ongoing prospective randomized clinical trial comparing OW and CW HTOs. Digital standing hip-knee-ankle (HKA) radiographs as well as lateral radiographs in 30° of flexion were obtained preoperatively and at 6 months for each patient. Joint line angles, HKA angle, leg length, Insall-Salvati index, Miura-Kawamura index and posterior tibial slope were measured using medical planning software. The complete preoperative radiological examinations of the first 50 patients were used in a study of intra- and inter-rater reliability of the measurements.
  
  
  RESULTS
  The mean posterior slope was reduced by 2.5° in CW HTO, whereas it remained unchanged in OW HTO (p < 0.001). Mean leg length decreased 5.7 mm in CW HTO and increased 3.1 mm in OW HTO (p < 0.001). Changes in joint line angles, patellar height indexes and the correction accuracy showed no significant differences comparing the two techniques. Frontal plane reliability measurement intra- and inter-rater intraclass correlation coefficient (ICC) varied from 0.81 to 0.99. Sagittal plane intra- and inter-rater ICC varied from 0.60 to 0.87. Posterior tibial slope intra- and inter-rater ICC showed the lowest values (0.70 and 0.60, respectively) corresponding to a smallest real difference of 4.5° and 5.5°, respectively.
  
  
  CONCLUSIONS
  Posterior tibial slope and leg length changes were significantly different in CW compared to OW HTOs. We recommend that possible alterations in tibial slope and leg length are considered when the technique of HTO is to be chosen. Landmark-based medical planning software shows good reliability and can be used in preoperative planning and postoperative evaluations of HTOs.
  
  
  METHODS
  I.
authors.affiliation: Department of Orthopedic Surgery, Martina Hansens Hospital, Box 823, 1306, Sandvika, Norway. kjnerhus@gmail.com.
authors.forename: Tor Kjetil
authors.initials: TK
authors.lastname: Nerhus
authors.affiliation: Department of Orthopedic Surgery, Martina Hansens Hospital, Box 823, 1306, Sandvika, Norway.
authors.forename: Arne
authors.initials: A
authors.lastname: Ekeland
authors.affiliation: Department of Orthopedic Surgery, Martina Hansens Hospital, Box 823, 1306, Sandvika, Norway.
authors.forename: Geir
authors.initials: G
authors.lastname: Solberg
authors.affiliation: Department of Orthopedic Surgery, Diakonhjemmet Hospital, Oslo, Norway.
authors.forename: Einar Andreas
authors.initials: EA
authors.lastname: Sivertsen
authors.affiliation: Department of Orthopedic Surgery, Oslo University Hospital, Oslo, Norway.
authors.forename: Jan Erik
authors.initials: JE
authors.lastname: Madsen
authors.affiliation: Department of Orthopedic Surgery, Martina Hansens Hospital, Box 823, 1306, Sandvika, Norway.
authors.forename: Stig
authors.initials: S
authors.lastname: Heir
mesh_terms: D000328:Adult; D006801:Humans; D007717:Knee / Q000000981:diagnostic imaging / Q000503:physiopathology; D007866:Leg / Q000000981:diagnostic imaging; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000601:surgery*; D010027:Osteotomy / Q000379:methods*; D010329:Patella / Q000000981:diagnostic imaging; D010808:Physical Examination; D011187:Posture; D011446:Prospective Studies; D011859:Radiography; D016059:Range of Motion, Articular; D015203:Reproducibility of Results; D013977:Tibia / Q000000981:diagnostic imaging / Q000601:surgery*
keywords: Closing wedge; Correction accuracy; High tibial osteotomy; Knee osteotomy; Leg length; Opening wedge; Patellar height; Posterior tibial slope