Natural history of solitary osteochondroma : a retrospective analysis of 236 patients in South Korea.

AIMS: The aim of this study was to analyze the natural history of solitary osteochondroma and determine how skeletal maturity influences tumour behaviour and treatment outcomes.

METHODS

A retrospective analysis of 236 patients with solitary osteochondroma (151 skeletally immature, 85 skeletally mature) was undertaken. Skeletal maturity was defined as bone age ≥ 18 years in males and ≥ 17 years in females. Tumour characteristics, disease progression, indications for surgery and recurrence rates were evaluated. Interobserver reliability for bone age assessment was excellent (intraclass correlation coefficient (ICC) 0.92 (95% CI 0.88 to 0.95)).

RESULTS

Spontaneous regression occurred exclusively in skeletally immature patients (17.2% (n = 26) vs 0%; p < 0.001). Skeletally immature patients predominantly presented with sessile lesions (76.2%; n = 115), had lower surgical needs (31.8%; n = 48), but higher progression rates (9.9% (n = 15) vs 1.2% (n = 1); p = 0.013). Skeletally mature patients showed more stable disease but required surgery more often (54.1%; n = 46). Among skeletally immature patients with regression, independent predictors were younger age at diagnosis (odds ratio (OR) 0.82 (95% CI 0.73 to 0.92); p < 0.001), proximal humeral location (OR 10.59 (95% CI 2.01 to 55.85); p = 0.005), and humeral shaft location (OR 38.93 (95% CI 4.81 to 315.10); p = 0.001). The optimal cutoff age for regression prediction was 14.8 years. No local recurrence occurred in the 94 operated patients.

CONCLUSION

Skeletal maturity fundamentally determines the natural history of osteochondroma. Conservative management with serial radiological follow-up is recommended for young patients, particularly those with humeral lesions, given their substantial potential for spontaneous regression. Earlier surgical intervention should be considered for skeletally mature patients with persistent symptoms.