Subtrochanteric Fracture following Removal of a Porous Tantalum Implant.

Osteonecrosis of the hip accounts for about 10% of all total hip arthroplasty cases and presents a significant challenge for those patients with and without femoral head collapse. Subtrochanteric femur fractures have been reported with numerous types of proximal femoral implants. Care must be taken to avoid penetrating the lateral cortex of the proximal femur inferior to the distal border of the lesser trochanter. Core decompression requires a 3 mm to 20 mm defect in the lateral femoral cortex. Subtrochanteric femur fractures are a well-known complication of core decompression as well. We present a case of a subtrochanteric fracture following the removal of a porous tantalum implant.

Technique for removal of cannulated screws.

Cannulated screws can become incarcerated or stripped during the process of initial open-reduction internal fixation or at the time of hardware removal. In addition, many different sizes and brands of cannulated screws exist, and the appropriate size or type of screwdriver may not be available. We describe a simple technique for cannulated screw removal that works for all types of screws and can be performed percutaneously using only a Steinmann pin and T- handle chuck or pin driver.

Femur fractures and lung complications: a prospective randomized study of reaming.

Reaming the intramedullary canal during fixation of femoral shaft fractures may contribute to pulmonary morbidity in patients with trauma. The purpose of our study was to compare acute and late pulmonary complications after reamed or nonreamed nailing of femur fractures. Patients who had femoral shaft fractures were randomized prospectively to a reamed (n = 41) or nonreamed (n = 41) femoral nailing group. Arterial blood gases were measured before and after femur fixation. Ratios of PaO2/FiO2 and alveolar arterial gradients were calculated. Pulmonary complications (acute respiratory distress syndrome) (ARDS), pneumonia, and respiratory failure) were monitored. Age, gender, fracture site, fracture type, time to nailing, length of operation, Injury Severity Score, and Abbreviated Injury Scale-thorax were similar for the two groups. No significant differences were observed in the ratio of PaO2/FiO2 ratios or alveolar arterial (A-a) gradients before and after nailing. The overall incidence of pulmonary complications was 14.6% (eight patients who had reamed nailing and four patients who had nonreamed nailing), and given the sample size, definitive conclusions could not be reached because of inadequate statistical power. We were unable to document differences in pulmonary physiologic response or clinical outcome between patients having reamed and nonreamed femoral nailing. This study may serve as a pilot investigation for other clinical investigations.

Are recombinant human bone morphogenetic protein-7 and tobramycin compatible? An experiment in rats.

OBJECTIVES: To evaluate the effects of local antibiotics on bone morphogenetic protein-induced new bone formation in vivo. DESIGN: In the research laboratory, inactive collagenous bone matrix was reconstituted with 1 microg of recombinant human bone morphogenetic protein-7 and implanted subcutaneously in the thorax bilaterally in 30 male Long-Evans rats. INTERVENTION: In group A (n = 2), the inactive collagenous bone matrix alone was implanted, bilaterally, and one of these pellets treated with either 500 microg tobramycin in aqueous solution or 3 tobramycin-impregnated polymethyl methacrylate beads. In group B (n = 4), the reconstituted pellets were not treated with tobramycin. In group C (n = 8), 1 reconstituted pellet in each rat was treated with 500 microg tobramycin in aqueous solution. In group D (n = 8), 3 tobramycin beads were placed in contact with 1 of the 2 reconstituted pellets in each rat. In group E (n = 8), 3 tobramycin beads were placed on the dorsal surface of 4 of the rats. All rats were killed on day 11. MAIN OUTCOME MEASUREMENT: Bone formation was evaluated by alkaline phosphatase assay and histology. Tobramycin elution from the beads after day 11 was measured by placing the explanted beads into a phosphate buffer solution to incubate for 24 hours. RESULTS: There was no difference in the alkaline phosphatase activity between the tobramycin treated and untreated implants. Histologic evaluation of the implants revealed areas of robust new bone formation in both the tobramycin treated and untreated implants. CONCLUSIONS: The results by both alkaline phosphatase assay and histologic evaluation in this rat model indicate that there is no inhibition of recombinant human bone morphogenetic protein-7-induced new bone formation by locally applied tobramycin. Recombinant human bone morphogenetic protein-7 is osteoinductive in the presence of locally applied tobramycin. A composite osteogenic device containing both tobramycin and recombinant human bone morphogenetic protein-7 may be developed that can simultaneously induce bone healing and decrease the risk for infection.