Potential influence of factors for genu valgus with hereditary multiple exostoses.

Genu valgus is one of the most common limb deformities in hereditary multiple exostoses (HME). However, it is easily concealed and may account for subsequent osteoarthritis of the knee. The knees of 56 patients (33 men and 23 women) with HME were investigated bilaterally. Knee valgus was described by the mechanical axis deviation (MAD), mechanical lateral distal femoral angle (LDFA), and medial proximal tibial angle (MPTA). We investigated sex, age, BMI, total number of palpable osteochondromas, number of radiographic osteochondromas around the knee, forearm deformities, morphology and distribution of lesions, and correlations between these factors and genu valgus. The measurement of LDFA and MPTA was performed to identify the sources of genu valgus deformity. Based on the measurement of the mechanical axis, limbs were classified as genu valgus (n = 22) or normal mechanical axis groups (n = 90). The different severities of the genu valgus patients were classified by MAD. By bivariate logistic regression, genu valgus was significantly associated with more sessile and flared metaphyseal lesions. However, only the number of flared metaphyseal lesions had a significant influence on the severity of genu valgus. By analyzing the LDFA and MPTA, it was found that abnormalities of both proximal tibia and distal femur play important roles in genu valgus. Early detection of sessile and flared metaphyseal knee lesions in patients with HME can contribute to early intervention of genu valgus. Level of relevance: Level 2.