Aneurysmal bone cysts (ABC): Retrospective analysis of two hundred and fifty eight cases

Aneurysmal bone cysts (ABCs) are bone tumours characterised by blood-filled cystic lesions. Management strategies for ABCs vary widely and lack consensus. This study aims to evaluate outcomes in 258 patients and investigate the factors affecting the recurrence rates.

This study is a single-centre retrospective analysis of patients diagnosed with ABC between January 1990 and December 2020. Patients who were histologically diagnosed with ABC, had available pathology, radiology, and surgery records, and were followed up for at least 24 months were included. Secondary ABCs were excluded. Presenting symptoms and location, computerised tomography (CT) and magnetic resonance imaging (MRI), treatment modalities, and recurrence were investigated.

The mean age of the 258 ABC patients was 17.25 ± 12.37 years, 67.44% being under 18 years, and 12.40% under five years. 49.45% were female. The average follow-up duration was 47.80 ± 41.92 months. Pain was the most common presenting symptom, reported by 79.97% of patients. 5.04% were asymptomatic and diagnosed incidentally, whereas 11.63% were diagnosed following a pathological fracture. The median disease-free survival was ten months, with the average time to first recurrence being 24.22 ± 22.14 months. Recurrence was more common in patients under five years of age (34.38% vs. 19.03%, p = 0.046) and in those with pathologic fractures (40.00% vs. 18.42%, p = 0.006). Conversely, recurrence was less common when burr and/or cautery was added to curettage (31.97% vs. 11.03%, p < 0.001). Time to recurrence was significantly shorter in cases with soft tissue oedema (median 5 vs. 12 months, p = 0.010) or fluid-fluid levels (median 6 vs. 12 months, p = 0.038).

The study found that pathological fractures and age under five years are associated with a higher risk of recurrence in aneurysmal bone cysts. Electrocauterization and/or high-speed burring as local adjuvant therapy is associated with low recurrence rates.