Lower extremity deformity and its risk factors in patients with solitary osteochondromas.

Background: This study aimed to demonstrate the occurrence of lower extremity deformities and their risk factors in patients with solitary osteochondromas. Methods: We retrospectively reviewed consecutive patients with solitary osteochondromas around the knee. The laterality (left or right), involved bone (femur or tibia), tumor type (pedunculated or sessile), and direction (medial or lateral) were examined. The whole limb length (WLL), mechanical lateral distal femoral angle (mLDFA), and medial proximal tibial angle (MPTA) were measured using teleroentgenogram. Lower limb deformity was defined as a difference of more than 5° in mLDFA or MPTA in both lower extremities or a difference in WLL of more than 1 cm. Patients were divided into two groups, with deformity and without deformity. Results: Lower extremity deformities were observed in 8 of 83 patients. Significant difference in the type of osteochondroma (p = 0.004) between the groups was observed. Differences in sex, age, laterality, involved bone, direction, and distance from the physis to the osteochondroma between groups were not statistically significant. The sessile type of osteochondroma was a risk factor for lower limb deformity with an odds ratio of 24.0 according to Firth's logistic regression analysis. Conclusion: In our cohort with solitary osteochondroma, lower limb deformities were observed in 8 (9.6%) out of the 83 patients and these were significantly associated with sessile-type tumors. Therefore, patients with sessile-type solitary osteochondroma around the knee require careful surveillance of lower limb alignment with whole leg teleroentgenogram. [ABSTRACT FROM AUTHOR]