Elsevier Acta Medica Okayama 09492658 26 3 2020 High body mass index is a risk factor for unfavorable clinical outcomes after medial meniscus posterior root repair in well-aligned knees 430 434 EN Ximing Zhang Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Takayuki Furumatsu Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Yuki Okazaki Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Takaaki Hiranaka Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Yuya Kodama Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Haowei Xue Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Yoshiki Okazaki Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Toshifumi Ozaki Department of Orthopaedic Surgery, Okayama University Hospital BackgroundSevere chondral lesions and varus knee alignment are associated with poor outcomes following transtibial pullout repair for medial meniscus posterior root tears and meniscus tear is strongly associated with body mass index. The prognostic factors in well-aligned knees (femorotibial angle < 180��) with mild chondral lesions are unknown. Therefore, we investigated the prognostic factors in these patients. We hypothesized that high body mass index would lead to poor clinical outcomes following pullout repair of medial meniscus posterior root tears. <br> MethodsWe retrospectively reviewed the files of 28 patients who had undergone pullout repair of medial meniscus posterior root tears between October 2016 and December 2017. We recorded the baseline characteristics (age, gender, height, weight, and body mass index) and the time between injury and surgery. We recorded the International Knee Documentation Committee scores, Knee injury and Osteoarthritis Outcome Scores, and pain visual analog scale scores. Using magnetic resonance imaging preoperatively and 1 year after surgery, we measured the medial meniscus body width and absolute and relative medial meniscus extrusion. Pearson correlation and multivariate linear regression analyses were used to assess potential associations between these factors and clinical outcomes. <br> ResultsAge positively correlated (coefficient = 0.49, P < 0.01) and body mass index negatively correlated with the postoperative International Knee Documentation Committee score (coefficient = �|0.64, P < 0.01). In multivariate linear regression analysis, body mass index was a significant factor leading to poor postoperative International Knee Documentation Committee score (R2 = 0.29, P < 0.05). <br> ConclusionsBody mass index > 30 kg/m(2) is a risk factor for unfavorable clinical outcomes following pullout repair of medial meniscus posterior root tears in well-aligned knees. Level of evidenceIII, Comparative retrospective study. No potential conflict of interest relevant to this article was reported.