Lower limb deformities and limb length discrepancies in hereditary multiple exostoses

Area of Science:

• Orthopedics
• Genetics
• Radiology

Background:

• Hereditary multiple exostoses (HME) is a genetic disorder characterized by the development of multiple osteochondromas.
• Patients with HME often exhibit lower limb deformities and limb length discrepancies.

Purpose of the Study:

• To evaluate the types and frequency of lower limb axial deviations and limb length discrepancies in HME patients.
• To identify specific exostoses as risk factors for these deformities.

Main Methods:

• Retrospective review of standing full-length radiographs from 32 HME patients (October 2009 - December 2020).
• Radiographic analysis included coronal limb alignment, limb length discrepancy measurement, and exostoses topography.
• A classification system for lower leg deformities related to exostoses was proposed.

Main Results:

• 19% of patients had a clinically significant limb length discrepancy (≥2 cm).
• 33% of patients presented with knee valgus deformity and 44% with ankle valgus deformity.
• Fibular growth anomalies (72% of lower legs) were a significant risk factor for knee valgus and limb length discrepancy; intertibio-fibular exostoses were also identified as risk factors.

Conclusions:

• Fibular exostoses, particularly intertibio-fibular types, are key risk factors for lower limb deformities and discrepancies in HME.
• Distal femoral exostoses did not correlate with genu valgum or limb length discrepancy.
• Close monitoring of HME patients with identified risk factors is recommended.