Revisiting Sex Differences in Multiple Hereditary Exostoses (MHE)

Background: Multiple Hereditary Exostoses (MHE) is an autosomal dominant, pediatric disorder characterized by the development of osteochondromas. These benign tumors can halt bone development and lead to pain, mobility issues, and growth abnormalities. MHE is male-predominant (1.5:1 male-to-female ratio), with males often displaying more acute symptoms. The underlying pathogenesis remains partially elucidated, and treatment primarily involves surgical intervention. Few studies address surgical statistics and question the assumed male predominance. This study seeks to provide an encompassing retrospective evaluation of MHE patients, emphasizing patient characteristics, surgical data, and sex discrepancies. Methods: We examined 103 MHE-diagnosed patients treated at the University of Iowa Hospitals and Clinics from June 2008 to March 2023. Comprehensive chart reviews elucidated surgical data. Demographic and clinical data were collected through data extraction and chart review. Statistical methods included a 2-sample t test (age differences between sexes) and a 2-sample Poisson test (excision rates between sexes). Results: The cohort consisted of 52 males and 51 females, indicating an equal sex distribution. Predominant excision sites included the distal femur (21.01%) and proximal tibia (19.33%). Significant sex differences were noted in surgical interventions: Males had a higher mean age of excision (23.30 y) than females (15.32 y) (95% CI: 11.48-19.16; P =0.03). Females exhibited a notably higher excision rate (CI: 1.17-2.00; P =0.001), with a ratio of 1.53 (female/male). Specifically, females had increased excisions at the foot/ankle (CI: 1.3-7.01; P =0.038) and hand/wrist (CI: 1.29-4.77; P =0.029). Conclusion: Our findings deviate from the commonly accepted male predominance in MHE, revealing an even male-female distribution. The distal femur and proximal tibia were the chief excision sites. Males exhibited later excisions, potentially due to delayed growth plate closure. Interestingly, females had a higher surgery rate, especially in the foot/ankle and hand/wrist. This deviates from earlier research proposing males have higher lesion counts, suggesting a more intricate sex-specific disease manifestation. This discovery underscores the necessity for continued exploration of sex variances in MHE. Level of Evidence: Level IV—retrospective case series.