Can low doses of simvastatin enhance fracture healing? An experimental study in rabbits.

Several observational and experimental studies have investigated the potential anabolic effects of statins on undisturbed bone but only a few recent studies have examined the effect of statins on skeletal repair. The goal of the study is to investigate any potential early anabolic effect of the systemic administration of simvastatin in low doses (based on earlier safety and efficacy studies on undisturbed bone) on fracture healing. Fifty-four skeletally mature male New Zealand White rabbits were used for the study. The rabbits were assigned to one of three experimental groups: a control group, and two groups that were orally administrated a diet with 10 and 30 mg/kg/day of simvastatin, respectively. A complete biochemical blood count was performed to exclude drug-induced complications. Half of the animals of each group were sacrificed at 15 days and the other half at 30 days after surgery at which time intervals healing quality was assessed. The bones were subjected to biomechanical testing, histomorphometric analysis and peripheral quantitative computed tomography. In animals received simvastatin of 30 mg/kg/day a significant reduction of BMD, stiffness, and energy absorbed to failure were observed. At 15 days, the amount of cartilaginous callus formation was reduced, and the void space was significantly increased, in the animals of both groups that received simvastatin when compared to the control group (p<.05). Our results suggest that simvastatin doses of 30 mg/kg/day may have a negative anabolic effect on callus formation in rabbits, whereas doses of 10 mg/kg/day seem not to produce a significant positive or a negative effect, especially at the early stages of fracture remodeling.

Evaluation of the Stryker S2 IM Nail Distal Targeting Device for reduction of radiation exposure: a case series study.

Distal locking is one challenging step during intramedullary nailing of femoral shaft fractures that can lead to an increase of radiation exposure. In the present study, the authors describe a technique for the distal locking of femoral nails, implementing a new targeting device in an attempt to reduce radiation exposure and operational time. Over a 2-year period, 127 consecutive cases of femoral shaft fractures were included in the study. All cases were treated with nailing of femoral shaft fractures with an unslotted reamed antegrade femoral nail and distal locking was performed with the use of a proximally mounted aiming device. Mean duration of the procedure was 63.5 18.1 min while the duration for distal locking was 6.6 +/- 2.6 min. In all successful cases, exposure from intraoperative fluoroscopy was 17.2 +/- 7.4 s for the whole operative procedure, and for distal locking was 2 shots, 1.35 s (range, 0.9-2.2 s) and 1.9 mGy (range, 1.1-2.9 mGy). Five cases (3.9%) were unsuccessful, but overall no intraoperative complications were encountered from the application of this technique. The ability of the device to correspond to the level of nail deformation and to properly identify the distal holes, reduced exposure to radiation compared to other published reports, and should be considered as a valuable tool for distal locking of femoral fractures.

Distal locking of tibial nails : a new device to reduce radiation exposure.

UNLABELLED: The indications for intramedullary nailing have expanded to include most tibial shaft fractures. Nail design has improved since their first introduction, but distal locking remains a difficult part of the procedure, resulting in radiation exposure to the patient and the surgeon and increased operation time. To address these issues, we describe an alternative surgical technique using a newly designed distal targeting device that consists of a proximally mounted aiming arm, and we report the preliminary data from its use in all tibial shaft fractures amenable to surgery for a 2-year period. Sixty-three tibial shaft fractures were treated with this method. The mean duration of the distal locking was 6.5 minutes, and in all successful cases, radiation exposure for distal locking was two shots (one shot before targeting and another for the confirmation of proper screw insertion). Radiation exposure was on average 0.85 seconds (range, 0.4-1.2 seconds) and 1.4 mGy (range, 0.8-1.9 mGy). There were no major intraoperative complications related to the technique. The method has certain advantages and can reduce radiation exposure and operation time. Nonetheless, familiarity with the instrumentation is a prerequisite for accurate distal locking. LEVEL OF EVIDENCE: Level IV Therapeutic study.