Investigating a potential biological treatment to prevent pathological fractures caused by unicameral bone cysts in children under 8 years.
BACKGROUND
There is no consensus on when and how to treat unicameral bone cysts (UBCs), partly because of a lack of knowledge of the aetiology.


OBJECTIVE
To review the different treatment techniques for UBCs and to describe our results with a single injection of autogenous bone marrow (BM) mixed with demineralised bone matrix (DBM) in very young children.


METHODS
We reviewed five patients under the age of 8 years with UBCs treated by percutaneous aspiration and a single injection of BM associated with DBM. The cyst was located in the proximal humerus in four patients and in the proximal femur in one patient. Assessment of the need for surgery was based on the clinical and radiographic suspicion of new pathological fractures. The administration of a second injection, when necessary, was based on the surgeon's judgement regarding the risk of fracture. The mean follow-up after first injection was 41 months.


RESULTS
There were no complications related to the procedure, except a non-displaced fracture, which healed without problems. All patients were pain free and progressively resumed their activities without restriction until a new fracture occurred in two cases. According to Capanna's classification, only one case healed completely (grade 1), one lesion was classified as grade 2, and there were three recurrences at 11, 12 and 27 months after initial treatment (grade 3). The final outcome was treatment failure for three out of the five patients. Two patients were treated with a second injection and one patient is waiting for surgery.


CONCLUSIONS
A single injection of aspirated autogenous BM mixed with DBM in very young children with active UBCs at risk of fracture is very simple, comfortable and safe. Nevertheless, the results seem to be unpredictable and are probably more dependent on the natural evolution of the cyst than on the treatment. Further comparative studies with larger sample numbers are needed.
Department of Traumatology and Orthopaedic Surgery, Hospital Universitario de León, León, Spai. Electronic address: luisramospascua@gmail.com.
Luis R
LR
Ramos-Pascua
Department of Traumatology and Orthopaedic Surgery, Hospital Universitario de León, León, Spai.
Sergio
S
Sánchez-Herraéz
Department of Traumatology and Orthopaedic Surgery, Hospital Universitario de León, León, Spai.
Paula
P
Casas-Ramos
Department of Radiology, Hospital Universitario de León, León, Spain.
Sebastián
S
Molnar Fuentes
Department of Radiology, Hospital Universitario de Salamanca, Salamanca, Spain.
José Ángel
JÁ
Santos Sánchez
D001691:Biological Therapy / Q000379:methods*; D001845:Bone Cysts / Q000150:complications* / Q000175:diagnosis / Q000628:therapy; D001853:Bone Marrow / Q000502:physiology; D002648:Child; D002675:Child, Preschool; D005260:Female; D005269:Femur / Q000293:injuries / Q000473:pathology; D005598:Fractures, Spontaneous / Q000209:etiology / Q000517:prevention & control*; D006801:Humans; D006811:Humerus / Q000293:injuries / Q000473:pathology; D008297:Male; D012189:Retrospective Studies; D016896:Treatment Outcome
Bone marrow; Children; Demineralised bone matrix; Femoral cyst; Humeral cyst; Pathological fracture; Percutaneous injection; Unicameral bone cyst