A Randomized Clinical Trial Comparing Curettage With Allogenic Bone Grafting and Curettage With Bioactive Glass Filling in Children With Bone Cysts CYSTS

Twenty patients will be randomized into each group. In all University Hospitals the treatment protocol will be same. Randomization will be performed using a sealed envelope technique.

Before surgery all patients will be examined clinically. After conventional radiographs all patients will be examined with magnetic resonance imaging showing cyst's size, anatomy, location and adjacent structures.

If the aneurysmal bone cyst is large or in difficult location, embolization by the radiologist can be used preoperatively.

Surgical technique:

Surgery will be done by experienced paediatric orthopaedic surgeons. Normal orthopaedic exposures will be used. The cyst is opened so that square window is done to the cortex. A sample to the pathologist is collected, also intraoperative frozen section is used to confirm the diagnosis. A mechanical curettage with use of a curette and a high speed burr is used to inspect the whole cavity. The tumour is resected as thoroughly as possible. After curettage 5% phenol is inserted to the cavity and it is neutralized with saline. Cyst volume is evaluated using saline (ml). Then the cyst is filled with morsellized femoral head allograft or bioactive glass (BG-S53P4) according to randomization. The biggest granule size 2-3,15mm is used for femur, tibia, pelvis and humerus. If the cyst volume is below 10ml in these places then smaller granule size (1-2mm) is chosen. If the cyst is in hand region then the granule size is 0,5-0,8mm. At the end of the operation the window's roof is inserted back. All the time X-ray is used to ensure that the whole cyst is treated properly. Osteosynthesis will be performed whenever it is necessary to prevent a pathological fracture.