The treatment of a comminuted open fracture of the lower extremity caused by high-energy trauma often requires serial débridements and preliminary external fixation before open reduction and internal fixation and wound closure10. The prevalence of complications, including delayed fracture-healing, nonunion, and deep infection, has stimulated interest in the use of the Ilizarov ring fixator, with initial shortening and early wound closure followed by a corticotomy and segmental bone transport for restoration of limb length11. The disadvantages of stabilization with a ring fixator and subsequent segmental bone transport include a high rate of delayed union or nonunion at the docking site, pin-loosening, pin-track infection, and the pain and inconvenience that are associated with the long treatment period7,12.
We report the case of a patient who had a comminuted fracture of the distal part of the femur that was associated with a large osseous defect, hypertrophic callus formation, and deep infection. The patient was managed successfully with multiple débridements and distraction osteogenesis through the callus.
*No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. No funds were received in support of this study.
†Unfall- und Wiederherstellungschirurgie, Medizinische Fakultät Charité, Campus Virchow-Klinikum, Humboldt Universität zu Berlin, Augustenburger Platz 1, 13353 Berlin, Germany. E-mail address for Dr. Raschke: michael.raschke@charite.de.
A thirty-nine-year-old man who had been involved in a motorcycle accident was initially seen at another institution for the treatment of multiple injuries, including a pulmonary contusion, a grade-II head injury (a score of 8 points on the Glasgow coma scale18), a Le Fort type-I maxillary fracture, a bilateral mandibular fracture, fractures of the ninth thoracic and first lumbar vertebrae, a supracondylar fracture of the left humerus, a fracture of the left olecranon, a fracture of both bones of the left forearm, bilateral hand injuries, an intertrochanteric fracture of the left femur, and a comminuted, open, grade-IIIB6 supracondylar fracture of the left femur (a type-33 A3.3 fracture according to the AO/ASIF classification system8) associated with a loss of eight centimeters of segmental bone from the distal aspect of the femur (Fig. 1). The intertrochanteric femoral fracture was stabilized with a Gamma nail, and the open supracondylar fracture was treated with extensive débridement and stabilization with a monolateral external fixator. Gentamicin-impregnated polymethylmethacrylate beads were implanted in the segmental bone defect to serve as a spacer.
Three weeks after the injury, the patient was transferred to our institution for treatment of the supracondylar fracture. Physical examination revealed an anterolateral soft-tissue defect, five by four centimeters in size, in the distal aspect of the thigh, overlying the segmental osseous defect. The neurovascular supply was intact, and the operative wound in the hip was healed. The left lower limb was approximately eight centimeters shorter than the right. Cultures of specimens obtained from deep within the soft-tissue defect were positive for methicillin-resistant Staphylococcus aureus. Radiographs showed early callus in the defect, with normal varus-valgus alignment and 15 degrees of hyperextension of the distal fragment (Fig. 2). The serum level of alkaline phosphatase, used as a predictor of hypertrophic callus formation and heterotopic ossification, was elevated to 690 international units per liter (normal, sixty to 180 international units per liter). The patient had recovered fully from the closed head injury at the time that he was admitted to our institution.
The patient was managed with extensive soft-tissue débridement followed by fracture stabilization and axial alignment performed with use of an Ilizarov hybrid external fixator (Smith and Nephew Richards, Memphis, Tennessee). The distal carbon ring (180 millimeters in diameter) was mounted parallel to the articular plane of the knee with three olive wires. The proximal carbon ring (20 millimeters in diameter) was mounted to the femoral shaft with one Kirschner wire and two half-pins. The malalignment in the sagittal plane was corrected and twenty-five millimeters of distraction of the defect was performed during this initial operation. The two rings were connected by telescopic rods to allow further distraction.
Distraction was started postoperatively at a rate of one millimeter per day (0.25 millimeter every six hours). The rate of distraction was increased to two millimeters per day (0.5 millimeter every six hours) after two weeks because rapid callus formation was seen on weekly radiographs. During the rest of the period of distraction, the rate of distraction was adjusted from a minimum of one millimeter to a maximum of two millimeters per day, depending on the local condition of the pin sites and the severity of the pain due to the distraction itself. Continuous passive motion of the knee and partial weight-bearing to a maximum of fifteen kilograms were allowed after the second postoperative week. The infection was controlled with vancomycin (500 milligrams administered intravenously three times daily for six weeks postoperatively) and repetitive soft-tissue débridements, including irrigation with the jet-lavage system in the operating room every two to three days for two weeks. By six weeks postoperatively, the defect had closed spontaneously with granulation tissue. Microbiological smears of the granulation tissue were negative for methicillin-resistant Staphylococcus aureus, but routine cultures of specimens from the nose, throat, perianal, and inguinal regions remained positive for three additional weeks. Radiographs of the distal aspect of the femur that were made three and six weeks after application of the Ilizarov fixator showed increased formation of callus.
By six weeks postoperatively, the initial shortening of the limb had been reduced from eight to two centimeters by distraction (Fig. 3). The total amount of distraction therefore was six centimeters, including the initial 2.5 centimeters that had been obtained at the time of application of the frame. Further lengthening could not be achieved because of premature consolidation of the callus, which led to bending of the Kirschner wires. We recommended an osteotomy as a means of continuing the lengthening procedure, but the patient refused. Radiographs that were made eight weeks postoperatively showed complete consolidation of the distracted callus. The fixator was removed, and progressive weight-bearing with use of a custom-fit brace was allowed for four weeks (Fig. 4).
The patient was discharged twelve weeks after the accident and nine weeks after the distraction was begun. The intertrochanteric fracture healed uneventfully. Twenty-six months after the injury, the patient had a slight limp but had no pain in the thigh or the knee. He was able to bear full weight, and he used a two-centimeter shoe-lift because of the limb-length discrepancy. The alignment of the left lower limb was symmetrical with that of the right, and the neurovascular status was normal. The range of motion of the left knee was 100 degrees of flexion and full extension. The traumatic wound was completely healed. Radiographs of the left femur revealed complete osseous consolidation and advanced remodeling. The serum level of alkaline phosphatase remained elevated at 214 international units per liter. Heterotopic ossification had developed at the site of the supracondylar humeral fracture; the ectopic bone impaired the range of motion of the elbow and subsequently was excised.
Our patient had a unique set of complex reconstructive problems. The supracondylar fracture of the femur was associated with eight centimeters of segmental bone loss and a large soft-tissue defect that was complicated by an infection with methicillin-resistant Staphylococcus aureus. Additionally, the ipsilateral intertrochanteric fracture had been treated with a Gamma nail, leaving only a short segment of the femoral shaft available for fixation and bone transport. The tendency of hypertrophic callus to form secondary to a head injury was beneficial in that it enabled us to reconstruct much of the osseous defect by distraction osteogenesis through the callus. The standard prolonged period of limb-lengthening, which is usually accompanied by pain and complications at the pin sites, was therefore avoided. Paley12 described a general consolidation index (calculated as the total duration of treatment, in months, per centimeter of lengthening) of 1.7 months per centimeter in adults. In contrast, we observed a consolidation index (calculated as the total duration of treatment, in days, per centimeter of lengthening) of 0.35 month per centimeter because of the formation of hypertrophic callus.
Distraction osteogenesis has been reported to be a useful technique for the treatment of metaphyseal and diaphyseal fractures associated with severe soft-tissue injury4,9,14,17. The principal advantage of this minimally invasive technique is that it provides sufficiently stable fixation without the extensive soft-tissue dissection that is necessary for open reduction and internal fixation4. Therefore, the complications that arise in association with more invasive techniques can be avoided4,9. Several authors have described this method as being useful for callus distraction, especially in patients who have posttraumatic segmental defects2,3,11,13,19. Distraction of the hypertrophic callus at the site of an acute, comminuted fracture that is associated with severe bone loss, extensive soft-tissue damage, and deep infection has not been previously reported, to our knowledge. Severe soft-tissue damage complicated by infection could be considered a contraindication to the use of distraction osteogenesis at a fracture site.
Heterotopic ossification and hypertrophic callus formation following a head injury has been described by numerous authors1,15,16,20. The underlying mechanism is still unclear and is the subject of ongoing research, but humoral and neural mechanisms have been proposed1. Recent studies have suggested a number of factors that may predict heterotopic ossification and hypertrophic callus formation. These factors include the severity of the head injury; the pattern of injury, such as the involvement of joints; and various laboratory measurements, such as the serum level of alkaline phosphatase15. The hypertrophic and rapidly consolidating callus in our patient shortened the total duration of treatment of the eight-centimeter defect from the estimated average of nine to twelve months5 to only three months.
The combination of fracture stabilization and callus distraction may be a useful treatment alternative in the rare case of a patient who has a large osseous defect and a closed head injury. We believe that the rate of distraction in these patients should be individually adjusted to reflect their tendency toward more rapid bone formation and consolidation, and it may exceed the rate of one to two millimeters per day that was used for our patient. The period of treatment may then be shortened by taking judicious advantage of the unique potential for healing in such patients.