Pronounced femur malunion after pathological bone fracture due to a simple bone cyst in the shaft of the femur, treated using Ilizarov fixation: a case report.

BACKGROUND: Although a simple bone cyst carries the risk of pathological fractures, it rarely causes severe deformity. Here we report a case of severe femoral deformity after multiple pathological fractures due to simple bone cysts, and consider the reason for the progression of malunion despite multiple previous treatments. Finally, we propose a treatment option for malunion correction. CASE PRESENTATION: A 9-year, 7-month-old Japanese girl was referred to our facility with obvious deformity of her right femur, caused by multiple simple bone cyst-related pathological fractures. The deformity included bowing of approximately 90° and an internal rotation of 60° in the middle third of the femoral shaft. To correct this deformity, we excised the lesion, thus shortening the femur, then corrected the alignment and applied an Ilizarov fixator to extend the bone. At present, 3 years after surgery, the deformity has not recurred and our patient is living without any limitations in daily activities or regular exercise. CONCLUSIONS: When a long bone is in a prolonged state of deformation, the deformity not only progresses as the bone grows, but the soft tissues remain unbalanced and treatment becomes increasingly difficult. To prevent increasing bone deformity and fragility, the deformity should be corrected as quickly as possible using intramedullary nailing or other fixation techniques. We believe that our shortening-distraction method is effective for the treatment of severe deformity with unbalanced soft tissues.

An injectable composite material containing bone morphogenetic protein-2 shortens the period of distraction osteogenesis in vivo.

To investigate new methods that can decrease the duration of bone transport (BT) distraction osteogenesis, we injected composite materials containing recombinant human bone morphogenetic protein-2 (BMP-2) and induced the generation of a callus bridge by rapid segmental transport (4 mm/day) in a rabbit bone defect model. The composite materials consisted of BMP-2 (0, 30, or 100 µg), ß-tricalcium phosphate powder (ßTCP, 100 mg/animal; particle size, <100 µm), and polyethylene glycol (PEG; 40 mg/animal). A paste of equivalent composition was percutaneously injected at the lengthening and the docking sites after surgery and after BT, respectively. The radiographic, mechanical, and histological examinations 12 weeks post-operative revealed that the generation of bridging callus in the presence and in the absence of BMP-2 was significantly different. The callus mass in the bone defect region was adequately and consistently developed in the presence of 100 µg of BMP (administered for 6 weeks), and the bones were consolidated in 12 weeks. Such an adequate callus formation was not observed in the control animals without BMP-2 treatment. The result of this experimental study suggests the potential application of BMP-2 in accelerating callus formation and in enabling rapid bone transporting, thereby shortening the treatment period for the repair of diaphyseal bone defects by distraction osteogenesis.

New treatment method for developmental dysplasia of the hips after walking age: arthroscopic reduction with limboplasty based on the findings of preoperative imaging.

BACKGROUND: What makes treatment choice for developmental dysplasia of the hips diagnosed after walking age difficult is the poor understanding of prereduction conditions that obstruct the reduction in spatial terms. To evaluate these problems, we employed subtraction three-dimensional imaging to search for the factors involved in intraarticular obstruction. On the basis of the findings of preoperative subtraction threedimensional imaging from computed tomography, we developed a new method, a minimum invasive arthroscopic reduction with limboplasty, for reduction of developmental dysplasia of the hips after walking age. The purposes of this report were to: (1) describe the technique of the arthroscopic procedure, and (2) evaluate our new method using radiographic parameters. METHODS: Ten patients with ten hips with developmental dysplasia after walking age treated by arthroscopic reduction with limboplasty were included in this study. The mean age of the patients at reduction was 22.6 months (range, 18.6-29.7 months); mean age at follow up was 7.2 years (range, 3.9-10.9 years); and mean follow up was 5.4 years (range, 1.7-9.0 years). These ten hips were evaluated using radiographic measurements. RESULTS: Moderate or severe avascular necrosis of the femoral head was not observed. Two hips that had a spherical-shaped head with minimal residual height loss or coxa magna were classified as Kalamchi and MacEwen grade 1. Additional surgery had been performed for two hips classified as Severin group 4 during the course of follow up. These two hips were classified as Severin group 1 at final examination. One more hip was classified as Severin group 4 at final examination, and additional surgery was recommended. The remaining seven hips (70%) therefore obtained good evaluations by arthroscopic reduction with limboplasty alone. CONCLUSIONS: We developed a new reduction method by using an arthroscopic procedure for the reduction of developmental dysplasia of the hips after walking age when this dysplasia failed to be reduced with nonoperative methods. The result of our new method is acceptable because good evaluations were obtained in 70% of hips 5.4 years after reduction by our new method alone.

Antitumor necrotic factor agent promotes BMP-2-induced ectopic bone formation.

Etanercept (ETN), which is a recombinant human soluble tumor necrosis factor (TNF) receptor that inhibits TNF activity, is effective in the treatment of rheumatoid arthritis. We investigated the effect of ETN on recombinant human bone morphogenetic protein-2 (rhBMP-2)-induced ectopic bone formation in vivo. A block copolymer composed of poly-D,L-lactic acid with random insertion of p-dioxanone and polyethylene glycol (PLA-DX-PEG polymer) was used as the delivery system. Polymer discs (6 mm, 30 mg) containing 5 microg rhBMP-2 were implanted into the left dorsal muscle pouch of mice (n = 50). In the systemic administration groups (n = 5 per group), ETN was subcutaneously injected (25 mg/human = 12.5 microg/mouse) twice per week in a dose-dependent manner (placebo, 12.5 x 10(-3), 12.5 x 10(-1), 12.5, 125 microg), whereas a single dose of ETN (placebo, 12.5 x 10(-3), 12.5 x 10(-1), 12.5, 125 microg) was embedded in each rhBMP-2 polymer disc in the local administration groups (n = 5 per group). Three weeks after implantation, the mice were killed and the implants were analyzed. Implants in the optimally dosed groups had increased radiodensity, which was consistent with a significant increase in bone mineral content of the ossicles. Bone histomorphology revealed a significant increase in bone volume/total volume, number of osteoblasts, osteoblast surface/bone surface, and a significant decrease in the number of osteoclasts, osteoclast surface/bone surface in the optimal dosed systemic and locally administered groups. These data suggest that the optimal dose of ETN, administered either systemically or locally, enhanced the bone-inducing capacity of BMP with no apparent adverse systemic effects.

Blocking of tumor necrosis factor activity promotes natural repair of osteochondral defects in rabbit knee.

BACKGROUND AND PURPOSE: Osteochondral defects have a limited capacity for repair. We therefore investigated the effects of tumor necrosis factor (TNF) signal blockade by etanercept (human recombinant soluble TNF receptor) on the repair of osteochondral defects in rabbit knees. MATERIAL AND METHODS: Osteochondral defects (5 mm in diameter) were created in the femoral patellar groove in rabbits. Soon after the procedure, a first subcutaneous injection of etanercept was performed. This single injection or, alternatively, 4 injections in total (twice a week for 2 weeks) were given. Each of these 2 groups was divided further into 3 subgroups: a low-dose group (0.05 microg/kg), an intermediate-dose group (0.4 microg/kg), and a high-dose group (1.6 microg /kg) with 19 rabbits in each. As a control, 19 rabbits were injected with water alone. The rabbits in each subgroup were killed 4 weeks (6 rabbits), 8 weeks (6 rabbits), or 24 weeks (7 rabbits) after surgery and repair was assessed histologically. RESULTS: Histological examination revealed that the natural process of repair of the osteochondral defects was promoted by 4 subcutaneous injections of intermediate-dose etanercept and by 1 or 4 injections of high-dose etanercept at the various time points examined postoperatively (4, 8, and 24 weeks). Western blot showed that rabbit TNFalpha had a high affinity for etanercept. INTERPRETATION: Blocking of TNF by etanercept enabled repair of osteochondral defects in rabbit knee. Anti-TNF therapy could be a strategy for the use of tissue engineering for bone and cartilage repair.