Case reports: treatment of subtrochanteric and ipsilateral femoral neck fractures in an adult with osteopetrosis.

We describe a patient with autosomal-dominant osteopetrosis, a subtrochanteric fracture, and an ipsilateral femoral neck fracture treated with a hip spica cast Although the fracture united with coxa vara and external rotation deformities, the patient successfully returned to his normal activities of daily living. Operative fracture treatment in patients with osteopetrosis is difficult, and our patient provides evidence that with nonoperative treatment these patients can return to a functional level when operative treatment is not an option.

Effect of pulsed electromagnetic fields on maturation of regenerate bone in a rabbit limb lengthening model.

To study the effect of applying pulsed electromagnetic fields (PEMF) during the consolidation phase of limb lengthening, a mid-tibial osteotomy was performed in 18 adult New Zealand White rabbits and an external fixator was applied anteromedially. Animals were randomly assigned to treatment and control groups. After a 7-day latency period, the tibiae were distracted 0.5 mm every 12 h for 10 days. The treatment group received a 20-day course of PEMF for 60 min daily, coinciding with initiation of the consolidation phase. The control group received sham PEMF. Radiographs were performed weekly after distraction. Animals were euthanized 3 weeks after the end of distraction. Radiographic analysis revealed no significant difference in regenerate callus area between treatment and control tibiae immediately after distraction, at 1 week, 2 weeks, or 3 weeks after distraction ( p = 0.71, 0.22, 0.44, and 0.50, respectively). There was also no significant difference in percent callus mineralization ( p = 0.96, 0.69, 0.99, and 0.99, respectively). There was no significant difference between groups with respect to structural stiffness ( p = 0.80) or maximal torque to failure ( p = 0.62). However, there was a significant positive difference in mineral apposition rate between groups during the interval 1-2 weeks post-distraction ( p < 0.05). This difference was no longer evident by the interval 2-3 weeks post-distraction. While PEMF applied during the consolidation phase of limb lengthening did not appear to have a positive effect on bone regenerate, it increased osteoblastic activity in the cortical bone adjacent to the distraction site. Since the same PEMF signal was reported to be beneficial in the rabbit distraction osteogenesis when applied during distraction phase and consolidation phase, application of PEMF in the early phase may be more effective. Further work is necessary to determine optimal timing of the PEMF stimulation during distraction osteogenesis.

Quantification of the microstructural anisotropy of distraction osteogenesis in the rabbit tibia.

A longitudinal orientation of fibers and trabeculae has been observed histologically within distracted callus. This study quantified the intensity and angle of orientation of trabeculae within a distracted callus. Sixteen New Zealand white rabbits underwent unilateral tibial callus distraction with an external fixator across a mid-diaphyseal osteotomy. Included were: a seven-day postoperative latency period, ten days of distraction at 0.5 mm every 12 hours, and 20 days of post-distraction consolidation before euthanasia. Tibiae were removed, stripped of soft tissue, sectioned, and processed for decalcified histology. Micrographs of mid-coronal sections of the callus were evenly divided into 12 regions and underwent Fast Fourier Transform (FFT) analysis of the digitized image to determine the angle and intensity of the orientation of the bony trabeculae within the callus. The microstructure of the regenerate callus demonstrated an angle of orientation that uniformly matched that of cortical bone in all of regions of the callus and an intensity of orientation which approached that of cortical bone.

Linear increase in axial stiffness of regenerate callus during limb lengthening.

Distraction osteogenesis is a powerful tool for addressing segmental defects and limb-length discrepancies. Guidelines for the rate and rhythm of distraction have been described. The possibilities of early consolidation or nonunion threaten clinical success. A quantifiable method for monitoring the distraction gap would be useful. Previous methods to measure regenerate callus stiffness have not gained widespread clinical acceptance, largely because of cumbersome instrumentation. A rabbit tibial lengthening model was used to show the clinical utility of a digital torque wrench in monitoring axial stiffness of the regenerate bone callus during distraction osteogenesis. We confirmed the linear increase in peak torsional stiffness with time, which has been reported by others. This relationship may prove to be a useful clinical adjunct in guiding the rate and rhythm of distraction during limb lengthening.

Orthopedic injuries during Operation Enduring Freedom.

Orthopedic injuries comprise a majority of combat injuries seen in recent U.S. military conflicts. Interventions in the forward deployed area have played an important role in improving mortality rates of soldiers as well as outcome at a medical center level. A retrospective review was conducted on orthopedic injuries from Operation Enduring Freedom evaluated at Walter Reed Army Medical Center (WRAMC). Patients were grouped into one of five injury categories (open fracture, amputation, arterial injuries, neurological injuries, and soft tissue injury) with evacuation time (days from time of injury to arrival at WRAMC) and procedures performed before arrival at WRAMC evaluated. The average evacuation time for all orthopedic casualties was 7.9 days. There was an average of 2.6 procedures performed per patient before arrival at WRAMC. There was no difference in evacuation time among the injury groups. Those with only soft tissue injuries underwent fewer procedures than the other injury groups; however, there was no difference among the injury groups in terms of procedures performed. The number of procedures performed did not affect the evacuation time. Fifty-six percent of casualties required operative intervention after arrival at WRAMC. With the unavoidable evacuation time that all casualties must endure regardless of severity of the injury, early operative intervention in forward deployed medical assets, such as the forward surgical team and combat support hospital, remains a necessity for rehabilitative and reconstructive efforts of the soldiers at the medical center level.

Ilizarov external fixation salvage of failed intramedullary fixation of tibia with nail retention.

Failure of intramedullary fixation of the tibia presents a unique problem, as improving fracture alignment is often difficult after nail placement. The purpose of this study was to demonstrate the effectiveness of the Ilizarov technique in obtaining anatomic union after failed intramedullary fixation of the tibia. We reviewed medical records and plain radiographs of 4 men who, at a tertiary-care facility, presented with failed intramedullary fixation of the tibia. Mean age was 28 years (range, 23-36 years). All 4 patients underwent reduction and external fixation by the llizarov technique with retention of the intramedullary nail. Anatomic union was attained in each case. Thin-wire circular-frame external fixation by the Ilizarov technique was a viable salvage option for failed intramedullary fixation of the tibia.

Evaluation of orthopaedic injuries in Operation Enduring Freedom.

Orthopaedic injuries constitute a majority of the combat casualties in recent U.S. military conflicts. Orthopaedic injuries sustained in Operation Enduring Freedom from December 2001 to January 2003 that were treated in forward-deployed military medial facilities and evacuated to a U.S. army medical center were reviewed. The spectrum of injuries included open fractures, amputations, neurovascular, and soft-tissue injuries. Forty-four patients (85%) received treatment beyond local wound care prior to arrival at a military medical center. Debridement and irrigation was the most commonly performed procedure due to the contaminated nature of these combat injuries. There were no infections among patients with open fractures, and no patients with external fixators had pin tract infections. None of the open fracture patients underwent primary internal fixation or primary wound closure. The average time from injury to wound coverage of the open fracture wounds was 12 days. Two amputations were infected and were treated with revision and delayed wound closure. There were no primary amputations done at our institution due to infection or ischemia. All arterial injuries underwent urgent revascularization in a field hospital. None of the arterial repairs required revision after evacuation to a medical center. Operation Enduring Freedom has been an excellent example of how early and aggressive intervention in a forward-deployed area has a significant effect on rehabilitative and reconstructive efforts at a rear echelon tertiary care center.

Treatment of infected tibial nonunions with debridement, antibiotic beads, and the Ilizarov method.

This study of 10 patients presents the early results of a protocol of debridement, antibiotic bead placement, and use of the Ilizarov method with a circular external fixator for treatment of infected nonunions of the tibia in a military population. The nonunions resulted from high-energy fractures in nine cases and an osteotomy in one. The Ilizarov techniques used were transport (five cases), shortening and secondary lengthening (two cases), minimal resection with compression (one case), and resection with bone grafting (two cases). Flap coverage was required for five patients. There were two recurrences of infection (20%) among patients with the most compromised soft tissue. Only 50% of patients were able to perform limited duties while wearing the external fixator. Only four patients returned to active duty; however, three patients from special operations units were able to return to jump status. Six patients underwent medical retirement because of insufficient function, resulting from decreased ankle or knee range of motion and arthrosis or muscle weakness.

Evaluation of orthopaedic injuries in Operation Enduring Freedom.

Orthopaedic injuries constitute a majority of the combat casualties in recent U.S. military conflicts. Orthopaedic injuries sustained in Operation Enduring Freedom from December 2001 to January 2003 that were treated in forward-deployed military medical facilities and evacuated to a U.S. army medical center were reviewed. The spectrum of injuries included open fractures, amputations, neurovascular, and soft-tissue injuries. Forty-four patients (85%) received treatment beyond local wound care prior to arrival at a military medical center. Debridement and irrigation was the most commonly performed procedure due to the contaminated nature of these combat injuries. There were no infections among patients with open fractures, and no patients with external fixators had pin tract infections. None of the open fracture patients underwent primary internal fixation or primary wound closure. The average time from injury to wound coverage of the open fracture wounds was 12 days. Two amputations were infected and were treated with revision and delayed wound closure. There were no primary amputations done at our institution due to infection or ischemia. All arterial injuries underwent urgent revascularization in a field hospital. None of the arterial repairs required revision after evacuation to a medical center. Operation Enduring Freedom has been an excellent example of how early and aggressive intervention in a forward-deployed area has a significant effect on rehabilitative and reconstructive efforts at a rear echelon tertiary care center.

The effect of low intensity pulsed ultrasound on regenerate bone in a less-than-rigid biomechanical environment.

The purpose of this study was to investigate effects of low intensity pulsed ultrasound (LIPU) on distraction osteogenesis in a less-than-rigid biomechanical environment in a rabbit model. A less-rigid mini-lengthener was applied and a mid-tibial osteotomy performed in 20 New Zealand White rabbits. After a 7 day latency period, the tibiae were distracted 0.5 mm every 12 hours for 10 days. Ten of the rabbits received LIPU for 20 min/day (ultrasound group) and 10 received sham LIPU (control group) from day 17 until sacrifice on day 37. Radiographs were taken weekly after distraction and the callus area was measured. After sacrifice, dual-energy X-ray absorptiometry (DEXA), torsional testing to failure, and histomorphometry were performed. On radiographs, all the treatment tibiae displayed persistent radiolucencies; however, only one of the control tibiae displayed a radiolucent interzone. Torsional strength of the treatment group was 54% of the contralateral tibia compared to 139% in the control group (p<0.008). Bone density and callus size were not significantly different between the 2 groups; however, the ultrasound group displayed a tendency towards more cartilage and fibrous tissue formation (p<0.16) and less bone (p<0.16) than controls. In a biomechanically unstable environment, LIPU appears to stimulate more cartilage formation in regenerated callus than in controls. This callus is biomechanically inferior to unstimulated callus at the early stage of healing tested. During distraction osteogenesis a sound biomechanical environment is important to achieving anticipated results.

The effect of low intensity pulsed ultrasound applied to rabbit tibiae during the consolidation phase of distraction osteogenesis.

The purpose of this study was to determine if low intensity pulsed ultrasound (LIPU) accelerated the maturation of regenerate bone when applied after distraction in a rabbit model. A mid-tibial osteotomy was performed in 26 New Zealand white rabbits and an external fixator applied anteromedially. After a seven day latency period, the tibiae were distracted 0.5 mm every 12 h for 10 days. Thirteen of the rabbits received LIPU for 20 min/day (treatment group) and 13 received sham LIPU (control group) from day 17 until sacrifice on day 37. Radiographs were taken weekly after distraction and the total and mineralized areas of the callus were measured. After sacrifice, dual-energy X-ray absorptiometry, torsional testing to failure, and histomorphometry were performed. Ultrasound-treated tibiae were a mean of 68.8 +/- 3.8% as stiff as and 68.2 +/- 6.0% as strong as the contralateral tibiae. Control tibiae were 78.7 +/- 7.0%, as stiff as and 70.2 +/- 7.9% as strong as the contralateral tibiae. The differences in stiffness and strength were not significant (p = 0.39 and 0.81, respectively) with the number of the animals tested in the study. The treatment group was 91.6% as dense as the contralateral side and the control group was 88.5% as dense as the contralateral side (p = 0.84). Radiographs revealed a significantly larger callus in the LIPU-treated tibiae at 1, 2 and 3 weeks after distraction compared to control tibiae (p < 0.01, 0.008 and 0.05, respectively). Histomorphometry revealed significantly less fibrous tissue in the LIPU-treated tibiae (p < 0.05) and a strong trend towards more bone in the LIPU-treated tibiae compared to controls (p = 0.06). LIPU was found to increase the size of the distraction callus and it might alter the composition of regenerate bone but it did not have a positive effect on the mechanical properties or density of regenerate bone when applied during the consolidation phase of distraction osteogenesis.

Percutaneous pin fixation of a femoral neck fracture complicated by deep infection in a 12-year-old boy.

Avascular necrosis with or without resultant limb-length discrepancy and problems with bony union is not uncommon after femoral neck fractures in the pediatric population. This rare case of infection after closed reduction and percutaneous pinning of an intracapsular fracture of the hip in a child illustrates the treatment difficulties posed by joint sepsis and the value of modern scanning techniques.

The "floating ankle": a pattern of violent injury. Treatment with thin-pin external fixation.

The "floating ankle" is an underappreciated pattern of injury that results from violent trauma and/or blast injuries in military personnel. It is characterized by an intact ankle mortise with a distal tibia fracture and an ipsilateral foot fracture, creating instability around the ankle. This pattern of injury may be the result of the military boot, which both protects the foot from immediate amputation or further injury and renders the distal tibia susceptible to fracture at the boot top. Four patients with open floating ankle injuries were treated with thin-pin circular fixation with good results. Two patients required bone transport for segmental loss. All patients are ambulatory without assistance or bracing. Thin-pin external fixation is a reasonable approach to this complex injury pattern, especially in the presence of marked soft tissue compromise with or without segmental bone loss.