2015 ISAKOS Biennial Congress ePoster #1707

Sagittal Inclination of Osteotomy in the Medial Open-Wedge High Tibial Osteotomy: Frequency of the Anterior-Inclined Osteotomy and Its Influence on the Posterior Tibial Slope

Jung-Ro Yoon, MD, PhD, Seoul KOREA, REPUBLIC OF
Seung Yup Lee, MD, Seoul, None KOREA, REPUBLIC OF
Jae-Hyuk Yang, MD, PhD, Guri, Gyeonggi-do KOREA, REPUBLIC OF
Jihoon Bae, MD, PhD, Seoul KOREA, REPUBLIC OF
Jae-Gyoon Kim, MD, PhD, Prof., Ansan, Gyeonggi KOREA, REPUBLIC OF
Ki-Mo Jang, MD, PhD, Prof., Seoul KOREA, REPUBLIC OF
Hong Chul Lim, MD, Seoul KOREA, REPUBLIC OF

Veterans Health Service Medical Center, Seoul, KOREA

FDA Status Cleared

Summary: Although parallel osteotomy in sagittal plane relative to medial joint line was planned, only 12.9% of cases achieved the parallelism as we defined.

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Abstract:

Purpose

Unlike postoperative changes in posterior tibial slope (PTS) after medial open-wedge high tibial osteotomy (OWHTO), sagittal osteotomy inclination has not been examined. It has been recommended that the line of osteotomy in the sagittal plane be parallel to the medial PTS.We aimed to determine the frequency of parallel osteotomy in medial OWHTO using postoperative lateral radiographs. Furthermore, we analyzed the correlations between sagittal osteotomy inclination and other radiological parameters.

Methods

To determine sagittal osteotomy inclination, we measured the angle between the medial joint line and osteotomy line, which is the lowest line of the proximal segment, on lateral radiographs of the knee; sagittal obliquity of the osteotomy relative to the medial joint line (SOOJ). A positive SOOJ value indicates that the anterior portion of the osteotomy is distally inclined relative to the medial joint line. The anterior-inclined osteotomy (AIO), parallel osteotomy, and posterior-inclined osteotomy were defined by an SOOJ more than 5°, between 5° and -5°, and less than -5°, respectively.

Results

The mean SOOJ was 15.1°, and 87.1% of knees showed an AIO. There was a significantly positive correlation between the postoperative PTS and the SOOJ (r, 0.33; 95% confidence interval [CI], 0.19 – 0.46; P < 0.001). The postoperative change in PTS also showed a significantly positive correlation with the SOOJ (r, 0.35; 95% CI, 0.21-0.47; P < 0.001).

Conclusions

Although parallel osteotomy in the sagittal plane relative to the medial joint line was planned, only 12.9% of cases achieved the parallelism sought under our definition.