title: Three-dimensional knee motion before and after high tibial osteotomy for medial knee osteoarthritis.
abstract: BACKGROUND
  High tibial osteotomy (HTO) is an established surgical option for treating medial knee osteoarthritis. HTO moves the mechanical load on the knee joint from the medial compartment to the lateral compartment by changing the leg alignment, but the effects of the operation remain unclear. The purpose of this study was to evaluate the change in three-dimensional knee motion before and after HTO, focusing on lateral thrust and screw home movement, and to investigate the relationship between the change in knee motion and the clinical results.
  
  
  METHODS
  A series of 19 patients with medial knee osteoarthritis who had undergone HTO were evaluated. We performed a clinical assessment, radiological evaluation, and motion analysis at 2.4 years postoperatively. The clinical assessment was performed using the Japanese Orthopaedic Association knee score.
  
  
  RESULTS
  The score was significantly improved in all patients after operation. Motion analysis revealed that lateral thrust, which was observed in 18 of the 20 knees before operation, was reduced to 7 knees after operation. Regarding active terminal extension of the knee, three patterns of rotational movement were observed before operation: screw home movement (external rotation), reverse screw home movement (internal rotation), and no rotation. By contrast, after operation, only reverse screw home movement and no rotation were observed; the screw home movement disappeared in all patients. In the knees with reverse screw home movement after operation, the preoperative score was significantly lower than those in the knees with no rotation after operation.
  
  
  CONCLUSIONS
  Kinetically, HTO was useful for suppressing lateral thrust in medial knee osteoarthritis, although the rotational movement of the knee joint was unchanged.
authors.affiliation: Division of Orthopedic Surgery, Department of Regenerative and Transplant Medicine, Niigata University Graduate School of Medicine and Dental Sciences, and Department of Orthopaedic Surgery, Niigata Kobari Hospital, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Takemae
authors.forename: Go
authors.initials: G
authors.lastname: Omori
authors.forename: Katsutoshi
authors.initials: K
authors.lastname: Nishino
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Terajima
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Koga
authors.forename: Naoto
authors.initials: N
authors.lastname: Endo
mesh_terms: D000328:Adult; D000368:Aged; D053587:Arthrometry, Articular / Q000379:methods; D001696:Biomechanical Phenomena; D001863:Bone Screws; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000601:surgery*; D010027:Osteotomy; D016059:Range of Motion, Articular; D013977:Tibia / Q000601:surgery*; D016474:Weight-Bearing / Q000502:physiology*