title: A predictive factor for acquiring an ideal lower limb realignment after opening-wedge high tibial osteotomy.
abstract: Obtaining a correct postoperative limb alignment is an important factor in achieving a successful clinical outcome after an opening-wedge high tibial osteotomy (OWHTO). To better predict some of the aspects that impact upon the clinical outcomes following this procedure, including postoperative correction loss and over correction, we examined the changes in the frontal plane of the lower limb in a cohort of patients who had undergone OWHTO using radiography. Forty-two knees from 33 patients (23 cases of osteoarthritis and 10 of osteonecrosis) underwent a valgus realignment OWHTO procedure and were radiographically assessed for changes that occurred pre- and post-surgery. The mean femorotibial angle (FTA) was found to be 182.1 +/- 2.0 degrees (12 +/- 2.0 anatomical varus angulation) preoperatively and 169.6 +/- 2.4 degrees (10.4 +/- 2.4 anatomical valgus angulation) postoperatively. These measurements thus revealed significant changes in the weight bearing line ratio (WBL), femoral axis angle (FA), tibial axis angle (TA), tibia plateau angle (TP), tibia vara angle (TV) and talar tilt angle (TT) following OWHTO. In contrast, no significant change was found in the weight bearing line angle (WBLA) after these treatments. To assess the relationship between the correction angle and these indexes, 42 knees were divided into the following three groups according to the postoperative FTA; a normal correction group (168 degrees < or = FTA < or = 172 degrees ), an over-correction group (FTA < 168 degrees ), and an under-correction group (FTA > 172 degrees ). There were significant differences in the delta angle [DA; calculated as (pre FTA - post FTA) - (pre TV - post TV)] among each group of patients. Our results thus indicate a negative correlation between the DA and preoperative TA (R(2) = 0.148, p < 0.05). Hence, given that the correction errors in our patients appear to negatively correlate with the preoperative TA, postoperative malalignments are likely to be predictable prior to surgery.
authors.affiliation: Department of Orthopaedic Surgery, Yokohama City University School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan. haru-b12@fukuhp.yokohama-cu.ac.jp
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Bito
authors.forename: Ryohei
authors.initials: R
authors.lastname: Takeuchi
authors.forename: Ken
authors.initials: K
authors.lastname: Kumagai
authors.forename: Masato
authors.initials: M
authors.lastname: Aratake
authors.forename: Izumi
authors.initials: I
authors.lastname: Saito
authors.forename: Riku
authors.initials: R
authors.lastname: Hayashi
authors.forename: Yohei
authors.initials: Y
authors.lastname: Sasaki
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Aota
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Saito
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D053587:Arthrometry, Articular / Q000379:methods; D017760:Bone Malalignment / Q000000981:diagnostic imaging / Q000209:etiology*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000601:surgery; D008297:Male; D008875:Middle Aged; D010027:Osteotomy / Q000009:adverse effects* / Q000379:methods*; D011237:Predictive Value of Tests; D011859:Radiography; D013977:Tibia / Q000000981:diagnostic imaging / Q000601:surgery*; D016896:Treatment Outcome