Osteofibrous dysplasia arising in the humerus: A case report

A genetic mouse model mimicking MET related human osteofibrous dysplasia is characterized by delays in fracture repair and defective osteogenesis

Osteofibrous dysplasia (OFD) is a rare, benign, fibro-osseous lesion that occurs most commonly in the tibia of children. Tibial involvement leads to bowing and predisposes to the development of a fracture which exhibit significantly delayed healing processes, leading to prolonged morbidity. We previously identified gain-of-function mutations in the MET gene as a cause for OFD. In our present study, we test the hypothesis that gain-of-function MET mutations impair bone repair due to reduced osteoblast differentiation. A heterozygous Met exon 15 skipping (MetΔ15-HET) mouse was created to imitate the human OFD mutation. The mutation results in aberrant and dysregulation of MET-related signaling determined by RNA-seq in the murine osteoblasts extracted from the wide-type and genetic mice. Although no gross skeletal defects were identified in the mice, fracture repair was delayed in MetΔ15-HET mice, with decreased bone formation observed 2-week postfracture. Our data are consistent with a novel role for MET-mediated signaling regulating osteogenesis.

Pathological Distal Tibial and Fibular Fracture in a Paediatric Patient: A Case Report

Paediatric distal tibial and fibular fractures are seen quite regularly in orthopaedic trauma practice. Most patients are managed conservatively with closed reduction or casting while only a selected few required surgical treatment. Surgical options include plating, percutaneous Kirschner wires, rigid intramedullary nails, and flexible intramedullary nailing. This is dependent upon the patient’s age, fracture site, comminution, and concomitant injuries. Here, we present an interesting case of a patient with an unusual lesion seen at the fracture site. This lesion was curetted out during surgery and filled with an injectable synthetic Cerament bone void filler (Bone Support AB, Lund, Sweden), which later formed into bone and allowed the bone to remodel.

Does the management of osteofibrous dysplasia of the tibia and fibula in children should be tailored to the extent and location of the lesion? A case control study investigating different surgical options

BACKGROUND

Osteofibrous dysplasia (OFD) is a rare non neoplastic, self-limited intracortical fibro-osseous lesion that most commonly affects the diaphysis of the tibia and fibula of children, the best treatment is still debated. Therefore we performed a retrospective study in children mostly under 10 years old with OFD aiming to determine whether early surgery is necessary and which is the best treatment.

HYPOTHESIS

Symptomatic OFD lesions should be treated proactively, and appropriate treatment can achieve favorable outcome.

METHODS

We retrospectively reviewed 23 patients with OFD of the tibia (n=22) and fibula. Management varied according to the severity of symptoms (deformity, pain or pathological fracture) and the extent of the lesion. Cases were divided into four groups (Gr.): Gr. 1: observation (n=4); Gr. 2: curettage and allograft (n=6); Gr. 3: curettage, allograft and elastic stable intramedullary nailing (ESIN) fixation (n=9); Gr. 4: extra-periosteal resection and bone transport (n=5). One patient received two different treatments successively (23 patients and 24 cases). All patients had regular clinical and radiographic follow-up to assess bone consolidation and complications.

RESULTS

In Gr. 1, four asymptomatic patients underwent observation after open biopsy. Gr. 4 had the lowest local recurrence rate: 0 cases (0%) vs. 4 (66.7%; Gr. 2) vs. 1 (11.1%; Gr. 3) (p=0.002), incidence of deformity: 0 case (0%) vs. 0 (0%; Gr. 2) vs. 3 (50%; Gr. 3) (p=0.023), and pathological fracture: 0 case (0%) vs. 0 (0%; Gr. 2) vs. 1 (16.7%; Gr. 3) (p=0.006), although the consolidation time was longer: 6.8 vs. 2 (Gr. 2) vs. 2.7 months (Gr. 3) (p=0.017) and the rate of complication was higher than those of Gr. 2 and Gr. 3 (p<0.05). Gr. 3 had a lower local recurrence rate: 1 case (11.1%) vs. 4 cases (66.7%) (p=0.002), incidence of deformity: 0 case (0%) vs. 3 cases (50%) (p=0.023), and pathological fracture: 0 case vs. 1 case (16.7%) (p=0.006) than Gr. 2.

DISCUSSION

Open biopsy is an important step in the management of patients with imaging suggestive of OFD in order to rule out Adamantinoma and other bone tumors or infection. Observation should be reserved for asymptomatic patients, while surgical treatment is indicated in patients with persistent pain, pathological fracture or significant deformity of the tibia. ESIN is a valid option to preserve the anatomical axis of the tibia in symptomatic patients with lesions of limited size; large circumferential lesions or recurrence can be managed by extra-periosteal resection and bone transport, although the complication rate can be relatively high.

LEVEL OF EVIDENCE

III; case control study.