Obesity is a risk factor for osteoarthritis progression and spontaneous osteoporosis is a risk for the development of spontaneous osteonecrosis in patients with medial meniscus posterior root tear

Background: Obesity is a representative risk factor for osteoarthritis (OA). The relationship between osteoporosis and executed osteonecrosis has been reported. The primary aim of this study was to determine the influence of obesity and osteoporosis on disease progression in patients with medial meniscus posterior root tear (MMPRT). Methods: We included 41 knees with MMPRT in this study. MMPRT was diagnosed based on the presence of both a meniscus ghost sign and a vertical linear defect on MRI. OA progression and development of osteonecrosis were evaluated using plain radiographs obtained at the initial visit and the final follow-up. The follow-up period for all knees was 30 ± 8 (mean ± standard deviation) months. Patients’ physical attributes were assessed at initial visits; these attributes included body mass index (BMI) and the clinical risk for osteoporotic fracture, as determined by the World Health Organization fracture risk assessment tool (FRAX). Patients with a BMI ≥25 kg/m² were classified in the obesity group and those with a BMI <25 kg/m² in the control group. Patients with a FRAX score of ≥10% were classified in the high FRAX group and those with a FRAX score of <10% in the low FRAX group. Results: OA progression evaluated by Kellgren–Lawrence grading scale was observed in 75% patients in the obesity group (1 grade in 38%, 2 grades in 31%, and 3 grades in 6%) and 58% in the control group (1 grade in 58%). Patients in the obesity group showed significantly greater OA progression. Spontaneous osteonecrosis was observed in no knees at the initial visit and six knees at the final follow-up. All six lesions were observed in the high FRAX group, which was statistically significant. Conclusions: OA progression and development of osteonecrosis were the two representative deterioration patterns in patients with MMPRT. High BMI was related with OA progression, and FRAX score of ≥10% with the development of osteonecrosis.