Sung Jae Kim1, Lich Thi Nguyen1, Young-Jin Seo1, Dawoon Jung1, Young-Soo Shin2, Jeehyoung Kim3, Jae-Young Choi4, Si Young Song5. 1. Department of Orthopaedic Surgery, Dongtan Sacred Heart Hospital, Hallym University College of Medicine, 7 Keunjaebong-gil, Hwaseong, Gyeonggi-do, 18450, Republic of Korea. 2. Department of Orthopaedic Surgery, Chuncheon Sacred Heart Hospital, Chuncheon, Republic of Korea. 3. Department of Orthopaedic Surgery, Seoul Sacred Heart General Hospital, Seoul, Republic of Korea. 4. School of Advanced Materials Science & Engineering, Sungkyunkwan University, Suwon, Republic of Korea. 5. Department of Orthopaedic Surgery, Dongtan Sacred Heart Hospital, Hallym University College of Medicine, 7 Keunjaebong-gil, Hwaseong, Gyeonggi-do, 18450, Republic of Korea. kneearthro@gmail.com.
Abstract
PURPOSE: The purpose of this study was to prospectively investigate osteotomy gap filling rates on serial plain radiographs, and to evaluate whether alignment correction is maintained after medial opening wedge high tibial osteotomy (MOWHTO) using a locking plate without bone graft. METHODS: Between March 2014 and June 2017, MOWHTO was performed without bone graft regardless of gap size. Radiographs were taken preoperatively, postoperatively, at 1, 3, 6, 12, 18, and 24 months after surgery. Radiographic examinations included a weight bearing long-standing anteroposterior (AP) view of the whole lower extremity, as well as, the AP, lateral, and both oblique views of the knee. Bone healing was measured on the medial oblique view of the knee. The postoperative alignment correction and its maintenance were assessed using the three radiologic parameters of the weight-bearing line (WBL) ratio, the hip-knee-ankle angle (HKAA), and the medial proximal tibial angle (MPTA) on the weight-bearing long-standing AP view of the lower extremity. RESULTS: Fifty-two consecutive patients underwent MOWHTO, but three patients failed to follow-up for more than 24 months. A total of 49 patients were assessed in this study. The median opening gap height was 10.0 mm (IQR, 8.0-12.0; range, 7-20). On immediate post-operative radiographs, the mean gap filling was 31.4 ± 3.6%. After 1, 3, 6, 12, 18, and 24 months, the mean gap filling rates increased to 38.7 ± 4.4%, 51.4 ± 6.6%, 66.5 ± 5.1%, 84.8 ± 7.0%, 92.4 ± 5.6%, and 97.8 ± 2.3%, respectively. Statistical differences were observed between all the follow-up evaluations (P < 0.001). Statistical differences in the WBL ratio, HKAA, and MPTA were observed between preoperatively and 1 month after surgery (P < 0.001). The mean PTSA increased significantly from preoperatively to postoperatively (P < 0.001). However, no statistical differences were found between the post-operative follow-up radiographs performed for these four values. CONCLUSION: MOWHTO using a locking plate without bone graft achieved at least 90% bone healing and had no loss in correction at 2 years postoperatively. LEVEL OF EVIDENCE: III.
PURPOSE: The purpose of this study was to prospectively investigate osteotomy gap filling rates on serial plain radiographs, and to evaluate whether alignment correction is maintained after medial opening wedge high tibial osteotomy (MOWHTO) using a locking plate without bone graft. METHODS: Between March 2014 and June 2017, MOWHTO was performed without bone graft regardless of gap size. Radiographs were taken preoperatively, postoperatively, at 1, 3, 6, 12, 18, and 24 months after surgery. Radiographic examinations included a weight bearing long-standing anteroposterior (AP) view of the whole lower extremity, as well as, the AP, lateral, and both oblique views of the knee. Bone healing was measured on the medial oblique view of the knee. The postoperative alignment correction and its maintenance were assessed using the three radiologic parameters of the weight-bearing line (WBL) ratio, the hip-knee-ankle angle (HKAA), and the medial proximal tibial angle (MPTA) on the weight-bearing long-standing AP view of the lower extremity. RESULTS: Fifty-two consecutive patients underwent MOWHTO, but three patients failed to follow-up for more than 24 months. A total of 49 patients were assessed in this study. The median opening gap height was 10.0 mm (IQR, 8.0-12.0; range, 7-20). On immediate post-operative radiographs, the mean gap filling was 31.4 ± 3.6%. After 1, 3, 6, 12, 18, and 24 months, the mean gap filling rates increased to 38.7 ± 4.4%, 51.4 ± 6.6%, 66.5 ± 5.1%, 84.8 ± 7.0%, 92.4 ± 5.6%, and 97.8 ± 2.3%, respectively. Statistical differences were observed between all the follow-up evaluations (P < 0.001). Statistical differences in the WBL ratio, HKAA, and MPTA were observed between preoperatively and 1 month after surgery (P < 0.001). The mean PTSA increased significantly from preoperatively to postoperatively (P < 0.001). However, no statistical differences were found between the post-operative follow-up radiographs performed for these four values. CONCLUSION: MOWHTO using a locking plate without bone graft achieved at least 90% bone healing and had no loss in correction at 2 years postoperatively. LEVEL OF EVIDENCE: III.