Association between medial posterior tibial slope and medial proximal tibial angle with medial meniscus posterior root tears

Although tibial plateau morphology is recognized as a critical determinant of meniscal pathology, the specific associations of the medial posterior tibial slope (MPTS) and medial proximal tibial angle (MPTA) with medial meniscus posterior root tears (MMRTs) remain underexplored in contemporary literature. This study aimed to evaluate the effects of MPTS and MPTA on MMRTs. Clinical data were retrospectively collected from patients undergoing knee arthroscopy for medial meniscus injuries between June 2023 and June 2024. A total of 78 patients were divided into the MMRTs group (MMRTs, n = 39) and the control group (tears in other parts of the medial meniscus, n = 39). The observed indices included gender, age, laterality, duration of illness, body mass index (BMI), Outerbridge classification of the medial compartment articular cartilage, MPTS, and MPTA. Independent-samples t tests, chi-square tests, and multivariable logistic regression analyses were used to compare variables between the 2 groups. Receiver operating characteristic curve analysis was employed to determine the critical values of risk factors. P < .05 was considered statistically significant. There were no statistically significant differences in age, laterality, gender, duration of illness, and BMI between the 2 groups (P > .05). The MPTS in the MMRTs group was significantly greater than in the control group (8.0° ± 0.8° vs 6.6° ± 1.0°, P < .05), the MPTA was significantly lower than in the control group (85.1° ± 1.4° vs 87.1° ± 1.4°, P < .05), and the intraoperative Outerbridge classification of the medial compartment articular cartilage was significantly higher in the MMRTs group compared with the control group (P < .05). Multivariable logistic regression analysis confirmed that MPTS > 7.35° (odds ratio = 9.663, 95% confidence interval: 2.863-32.621, P = .0003) and MPTA < 85.85° (odds ratio = 1.233, 95% confidence interval: 1.634-7.194, P = .0011) were independent anatomical risk factors for MMRTs after adjusting for age, gender, and BMI. Receiver operating characteristic curve analysis indicated that the optimal cutoff value for MPTS is 7.35° (sensitivity 79.5%, specificity 82.1%, area under the curve = 0.876), and the optimal cutoff value for MPTA is 85.85° (sensitivity 84.6%, specificity 71.8%, and area under the curve = 0.841). MPTS >7.35° and MPTA <85.85° are anatomical risk factors for MMRTs. Moreover, MMRTs can exacerbate the degeneration of articular cartilage, providing a critical reference for preoperative risk stratification and individualized treatment planning of knee joint diseases.