Michael W. Chapman

Morbidity at bone graft donor sites.

A review of the medical records of 239 patients with 243 autogenous bone grafts was undertaken to document the morbidity at the donor sites. The overall major complication rate was 8.6%. Major complications included infection (2.5%), prolonged wound drainage (0.8%), large hematomas (3.3%), reoperation (3.8%), pain greater than 6 months (2.5%), sensory loss (1.2%), and unsightly scars. Minor complications (20.6%) included superficial infection, minor wound problems, temporary sensory loss, and mild or resolving pain. There was a much higher complication rate (17.9% major) if the incision used for the surgery was also the same incision used to harvest the bone graft.

Treatment of Acute Fractures with a Collagen-Calcium Phosphate Graft Material. A Randomized Clinical Trial*†

A prospective, randomized clinical trial was conducted concurrently at eighteen medical centers in order to compare the safety and efficacy of two types of graft material for the treatment of fractures of long bones: autogenous bone graft obtained from the iliac crest, and a composite material composed of purified bovine collagen, a biphasic calcium-phosphate ceramic, and autogenous marrow. Two hundred and thirteen patients (249 fractures) were followed for a minimum of twenty-four months to monitor healing and the occurrence of complications. We observed no significant differences between the two treatment groups with respect to rates of union (p = 0.94, power = 88 per cent) or functional measures (use of analgesics, pain with activities of daily living, and impairment in activities of daily living; p > 0.10). The prevalence of complications did not differ between the treatment groups except for the rate of infection, which was higher in the patients who were managed with an autogenous graft. Twelve patients who were managed with a synthetic graft had a positive antibody titer to bovine collagen; seven of them agreed to have intradermal challenge with bovine collagen. One patient had a positive skin response to the challenge but had no complications with regard to healing of the fracture. We concluded that, for traumatic defects of long bones that necessitate grafting, use of the composite graft material appears to be justified on the grounds of safety, efficacy, and elimination of the increased operative time and risk involved in obtaining an autogenous graft from the iliac crest.

Compression-plate fixation of acute fractures of the diaphyses of the radius and ulna.

A retrospective study was done of eighty-seven patients who had 129 diaphyseal fractures of either the radius or the ulna, or both, and who were treated with fixation using an AO dynamic-compression plate. Open fractures were internally fixed primarily, and both comminuted and open fractures routinely had bone-grafting. Ninety-eight per cent of the fractures united, and 92 per cent of the patients achieved an excellent or satisfactory functional result. The rate of infection was 2.3 per cent. Refracture occurred after removal of a 4.5-millimeter dynamic-compression plate in two patients, but there were no refractures after removal of a 3.5-millimeter plate. The 3.5-millimeter-plate system gave excellent results in patients who had a fracture of the forearm, and it minimized the risk of refracture. Our results demonstrated that immediate plate fixation of an open fracture of the forearm, with a low rate of complications, is possible.

Bone ingrowth and mechanical properties of coralline hydroxyapatite 1 yr after implantation.

A previous study of coralline hydroxyapatite as a bone-graft substitute was extended from 4 to 12 months to determine better the relationships between implantation time, bone ingrowth and mechanical properties. The model consisted of a 10 x 30 mm window defect in the shaft of the canine radius (a cortical site), and a 10 mm diameter cylindrical defect in the head of the humerus (a cancellous site). In the new study, these two defects were made bilaterally in eight dogs, and filled with block-form coralline hydroxyapatite. The radius defects were supported by a metal fixation plate which was removed after 9 months. After 12 months, the dogs were killed and the left-side implants were analyzed histomorphometrically and mechanically. The right-side radius and humerus were reserved for structural analysis. The results were combined with those previously measured after 4, 8, 12 and 16 wk of implantation. In the cortical site, bone ingrowth increased from 52% at 16 wk to 74% at 1 yr. In the cancellous site, bone ingrowth was 38% after 4 wk, then fell monotonically, reaching 17% at 1 yr. Bending and compressive strength and stiffness of the radius implants increased throughout the post-implantation year, but compressive strength and stiffness of the humerus implants did not change after the first 2-4 months. Mechanical properties were strongly correlated to bone ingrowth in the cortical, but not the cancellous, site. The volume fraction of the coralline hydroxyapatite material diminished significantly with time in the cortical, but not the cancellous, site.

Effects of bone ingrowth on the strength and non-invasive assessment of a coralline hydroxyapatite material.

The dependence of strength on the amount of bone growth into a hydroxyapatite material made from coral was investigated. Block and granular forms of the material were implanted into cortical and trabecular regions of the skeletons of 16 dogs. The results were examined after 4, 8, 12 and 16 wk, with four dogs in each experimental group. When implanted into cortical bone, the bending strength of the implant material was found to be highly correlated with the amount of pore space which had become occupied by bone (r = 0.92, P less than 0.005 for the block form; r = 0.84, P less than 0.005 for the granular form). Multiple regression analysis showed that six histomorphometric measures of ingrowth accounted for 96% of the variability in bending strength of the block material, and there were no significant differences between block and granular forms of the material. On the other hand, when implanted into trabecular bone, the block form of the material achieved greater compressive strength than the granular form. While both strength and ingrowth increased with time, there were poor correlations between these two variables. Finally, when the material is implanted into trabecular bone, it becomes stronger in compression than the surrounding bone; when implanted in cortical bone, linear modelling suggests that resorption and replacement of the implant would be required to approximate the bending strength of the surrounding bone.

Immediate external fixation of unstable pelvic fractures

Immediate external fixation has been proposed as a means of stabilizing severe pelvic fractures to reduce the chance of organ failure and death. Sixty-six patients were admitted from January 1980 through December 1983 with double fractures of the pelvic ring that involved the posterior elements. Twenty-six patients (39 percent) underwent immediate external fixation for instability, and 40 patients (61 percent) with stable fractures were treated with bed rest. The two groups were similar in age, injury severity score, and degree of shock. The mortality rate of the two groups was the same (12 percent), as was the incidence of organ failure. The mean transfusion requirement in the unstable group was greater, but not significantly. Our results were better than those reported in recent studies in which immediate rigid fixation was not used. We conclude that the patient with multiple trauma without unstable pelvic fracture should undergo immediate external fixation to decrease morbidity and mortality rates and limit soft tissue damage.

Biomechanical consequences of fracture and repair of the posterior wall of the acetabulum.

We measured the distribution of contact area and pressure between the acetabulum and the femoral head of cadaveric pelves in three different conditions: intact, with an operatively created fracture of the posterior wall, and after anatomical reduction and fixation of the fracture with a buttress plate and interfragmentary screws. The study involved eight cadaveric hip joints from five pelves loaded to 2000 newtons in simulated single-limb stance. Measurements were made with pressure-sensitive film. The acetabulum was divided into three areas--the anterior wall, the superior aspect, and the posterior wall--for the analysis of the data. Creation of a fracture of the posterior wall was followed by an increase in contact area, maximum pressure, and contact force in the superior aspect of the acetabulum. A concomitant decrease in these parameters was observed in the anterior and posterior walls. Anatomical reduction and fixation of the fracture with a plate and screws did not restore the pattern of loading to pre-injury levels.

Treatment of Supracondylar Nonunions of the Femur with Plate Fixation and Bone Graft

BACKGROUND The purpose of this study was to review the results of single and double-plate fixation combined with grafting with bone from the iliac crest performed by one surgeon as treatment for supracondylar nonunion of the femur. METHODS We performed a retrospective study of eighteen adult patients in whom a nonunion of the supracondylar region of the femur had been treated with single or double-plate fixation and autologous bone graft. The average time from the initial treatment of the fracture or the osteotomy to the index repair of the nonunion was fifteen months (range, five to thirty-six months), and nine patients had had a total of fifteen operations between the initial treatment and the repair of the nonunion. Two of these patients had had at least three procedures. Thirteen double plates, four single plates, and one interfragmentary screw were used for fixation of the nonunions, with onlay autologous bone graft used in all patients. The average time from the repair of the nonunion to the latest follow-up examination was twenty-six months (range, six to 120 months). RESULTS By the time of the latest follow-up examination, all eighteen nonunions had healed. One patient had needed repeat double-plate fixation and autologous bone-grafting to obtain union. Two patients had had the hardware removed because of pain or infection, one patient had had an implanted electrical bone stimulator removed, and one patient had had a quadricepsplasty to treat restricted motion of the knee. There were only three complications. These included one infection, which resolved with irrigation and debridement and the use of antibiotics; loss of motion of one knee; and one malunion. The average range of motion of the knee at the latest follow-up examination was 101 degrees (range, 10 to 135 degrees). CONCLUSIONS Rigid plate fixation and autologous bone-grafting is an effective technique for the treatment of nonunions of the supracondylar region of the femur.

Biomechanical testing of new and old fixation devices for vertical shear fractures of the pelvis

Malgaigne fractures of the pelvis have been treated with many different methods of fixation. We developed a plate for use on the anterior aspect of the sacroiliac (SI) joint using information obtained from cadaveric dissections and computed tomography (CT) scans of male (50) and female (50) pelvises. We tested each of six pelvises in the Instron, with five different fixation systems. Our results showed that the weakest system was the anterior quadrilateral frame plus two symphyseal plates. When comparing three posterior screws with the SI joint plate, the difference was not statistically significant. However, in both of these systems, a second symphyseal plate added to the overall stability.

Treatment of femoral diaphyseal nonunions.

There have been conflicting reports regarding treatment of femoral diaphyseal nonunions using reamed intramedullary nailing. Although high union rates have been reported using this technique, not all orthopaedic surgeons have experienced the same success. A retrospective review of charts and radiographs of 39 adult patients with nonunions of the femoral diaphysis treated at the authors’ institution with reamed intramedullary nailing, compression, and with and without interlocking was done. The time from the index procedure to nonunion repair was 4 to 75 months (average, 19 months). Fifteen patients had 18 procedures between the index operation and nonunion repair. The average followup from nonunion repair to the most recent examination was 22.5 months (range, 3–108 months) with a median of 15 months. At the last followup, the overall union rate was 74% after one procedure and 97% after two or more procedures. There were seven complications including two infections, one pulmonary embolus, one occurrence of a deep venous thrombosis, a hematoma, and one case of malrotation. The data support the use of antegrade reamed nailing as a successful technique for treatment of most femoral diaphyseal nonunions.