James P. Waddell

Pelvic Disruption: Assessment and Classification

A precise radiologic technique for assessing the forces producing pelvic disruption has been helpful in arriving at a logical classification of pelvic injury. The radiologic examination should include anteroposterior, inlet and outlet views, as well as tomograms and occasionally computed-assisted tomographic evaluation (CT scanning). On the basis of this radiologic assessment with some biomechanical studies, a classification of three major forces producing injury is suggested. The anteroposterior and lateral compression types, while vastly different, may both have stable and unstable subtypes associated with them. The vertical shear fracture is always unstable. An accurate history and physical examination in conjunction with the above radiologic principles will lead the surgeon to a precise determination of the fracture pattern. A knowledge of the forces necessary to produce this pattern is helpful in the management of the patient with this particular traumatic lesion.

Cardiopulmonary function and pulmonary microemboli during arthroplasty using cemented or non-cemented components. The role of intramedullary pressure.

An experimental model was designed to investigate the role of intramedullary pressure on cardiopulmonary function and pulmonary pathology during arthroplasty using cemented and non-cemented components. Twenty-four dogs were divided randomly into three groups: a group that received a non-cemented implant in which low intramedullary pressure was generated, a group that received a cemented implant, and one that received bone wax and an implant; high intramedullary pressures were generated in the latter two groups. Bone wax was used to generate high intramedullary pressures without the use of bone cement. In the group with the non-cemented implant, few pulmonary microemboli and no significant cardiorespiratory changes were found. In the groups that received bone wax and an implant or the cemented implant, there were many pulmonary microemboli and significant cardiorespiratory changes, including decreased arterial oxygen tension, increased pulmonary arterial pressure, and increased intrapulmonary shunt fraction. There was no evidence that methylmethacrylate monomer was responsible for the cardiorespiratory changes in the group with the cemented implant.

The use of an antibiotic-impregnated, osteoconductive, bioabsorbable bone substitute in the treatment of infected long bone defects: Early results of a prospective trial

Objective We sought to evaluate the use of a bioabsorbable, tobramycin-impregnated bone graft substitute (calcium sulfate alpha-hemihydrate pellets) in the treatment of patients with infected bony defects and nonunions. Study Design/Methods Twenty-five patients (15 male and 10 female, mean age 43 years (range 27–69 years) requiring surgical debridement of culture-positive long bone infection (16 with associated nonunion) were entered into an ongoing consecutive, prospective clinical trial. Involved bones included the tibia (15), femur (6), ulna (3), and humerus (1). All defects were posttraumatic in origin, and each patient had had previous surgery at the involved site (mean 4.3 surgeries; range 1–8 surgeries). The duration of infection ranged from 4 months to 20 years (mean 43 months). According to the Cierny-Mader classification system, there was 1 stage I (medullary osteomyelitis), 6 stage III (localized osteomyelitis), and 18 stage IV (diffuse osteomyelitis) lesions. There were 4 normal (A) hosts and 21 locally and/or systemically compromised (B) hosts. Mean bone defect/void was 30.5 cm3 (range 3–192 cm3). Results Mean follow-up was 28 months (range 20–38 months). Radiographically, pellets were resorbed at a mean of 2.7 months postoperatively. Infection was eradicated in 23 of 25 patients (92%). Isolated bony defects healed in all nine patients without further treatment. Fourteen of 16 patients with nonunion achieved union, although nine required autogenous bone grafting. Union was achieved in five of seven nonunion patients treated with bone graft substitute in isolation. Complications included refracture (three), recurrence of infection (two), persistent nonunion (two), and superficial wound necrosis (one). Eight patients developed sterile draining sinuses that healed upon radiographic resorption of the pellets. Conclusions In patients with posttraumatic osteomyelitis, the bone graft substitute was effective in eradicating bone infection in 23 of 25 patients. Isolated bony defects healed reliably (nine of nine) following addition of bone graft substitute alone. The role of the bone graft substitute in isolation in the treatment of nonunion is unclear at present.

Functional outcome of thoracolumbar burst fractures without neurological deficit.

Thoracolumbar burst fractures are a major cause of disability; however, there are few studies on the functional outcome of patients with this injury. The purpose of this study is to evaluate the functional outcome of patients with thoracolumbar burst fractures using a generic and a condition-specific health status survey. The SF-36 survey (generic) and the Roland scale (condition-specific) were administered to 24 patients who had a minimum of 2 years follow-up after a thoracolumbar burst fracture without neurologic deficit. The average SF-36 score was 65% (compared to 45% for dialysis and 66% for diabetes) and the Roland score was 65% (compared to 58% for low back pain). Of the patients, 33% were able to return to their previous employment, but only 8% were able to return to their pre-injury level of sports. There was a strong correlation (r = 0.71) between the Roland scale and the SF-36 pain scale. There were poor correlations between the Roland scale and residual kyphosis (r = 0.003), and between the SF-36 pain scale and residual kyphosis (r = 0.10). There was no significant difference in the functional outcome of those patients treated operatively versus nonoperatively.

Biomechanical Evaluation of Periprosthetic Femoral Fracture Fixation

BACKGROUND A variety of methods are available for the fixation of femoral shaft fractures after total hip arthroplasty. However, few studies in the literature have quantified the performance of such repair constructs. The aim of this study was to evaluate biomechanically four different constructs for the fixation of periprosthetic femoral shaft fractures following total hip arthroplasty. METHODS Twenty synthetic femora were tested in axial compression, lateral bending, and torsion to determine initial stiffness, as well as stiffness following fixation of a simulated femoral midshaft fracture with and without a bone gap. Four fracture fixation constructs (five specimens per group) were assessed: construct A was a Synthes locked plate (a twelve-hole broad dynamic compression plate) with locked screws; construct B, a Synthes locked plate (a twelve-hole broad dynamic compression plate) with cables and locked screws; construct C, a Zimmer nonlocking (eight-hole) cable plate with cables and nonlocked screws; and construct D, a Zimmer nonlocking (eight-hole) cable plate with allograft strut, cables, and nonlocked screws. Axial stiffness, lateral bending stiffness, and torsional stiffness were assessed with respect to baseline intact specimen values. Axial load to failure was also measured for the specimens. RESULTS Construct D demonstrated either equivalent or superior stiffness in all testing modes compared with the other constructs in femora with both a midshaft fracture and a bone gap. A comparison of constructs A, B, and C demonstrated equivalent stiffness in all test modes (with one exception) in femora with a midshaft fracture and a bone gap. CONCLUSIONS A combination of a nonlocking plate with an allograft strut (construct D) resulted in the highest stiffness of the constructs examined for treating a periprosthetic fracture around a stable femoral component of a total hip replacement.

FRACTURES OF THE DENS [ODONTOID PROCESS]: An Analysis of Thirty-seven Cases

1. Thirty-seven cases of fracture of the dens have been studied. 2. The incidence of non-union was high: 64 per cent after apparently adequate closed treatment. 3. Possible causes of the high incidence of non-union have been studied : attention is drawn to the effect of displacement and to that of posterior displacement in particular. 4. Non-union of the dens with potential instability at the atlanto-axial joint is not acceptable in a patient who expects to lead a normal active life. 5. Atlanto-axial fusion is the method of choice in the treatment of instability ; once that has been secured, pseudarthrosis of the dens is no longer significant.

Anterior approach and stabilization of the disrupted sacroiliac joint

Pelvic fractures with disruption of the important weight-bearing sacroiliac area can lead to impaired gait due to malunion or pelvic obliquity, back or buttock pain arising from the sacroiliac joint, and permanent neurologic damage. In eight patients with sacroiliac joint dislocation, an anterior retrofascial approach and stapling of the sacroiliac joint was performed. Six of these patients maintained an anatomic reduction of the sacroiliac joint and their results were rated as excellent. Two of the eight patients had a slight loss of reduction and because of intermittent mild pain were rated as having fair results. In another eight patients, plate fixation of the anterior sacroiliac joint was done. New stabilization methods utilizing dynamic compression plates, reconstruction plates, and a new four-hole plate have been developed to provide more secure fixation of these unstable injuries.

Fractures of the tibial plateau: a review of ninety-five patients and comparison of treatment methods.

Ninety-five patients with fractures of the tibial plateau have been reviewed. The fractures were grouped, according to the X-ray pattern, into five fracture types. Treatment was grouped into plaster immobilization or traction in the conservative group, and open reduction with internal fixation, open reduction with bone grafting, or open reduction with internal fixation and bone grafting in the operated group. It was concluded from this review that tibial plateau depression or tibial plateau widening of less than 10 mm was usually tolerated well and did not preclude a successful result. Adequacy of reduction was a least as important as early motion in obtaining a satisfactory result regardless of the type of fracture treated. If open reduction is undertaken both internal fixation and bone grafting are required in the most common types of these fractures. The exceptions are Type I or split fractures which do not require a bone graft and Type III or central depression fractures which do not require internal fixation.

Lateral impact motor vehicle collisions: Significant cause of blunt traumatic rupture of the thoracic aorta

BACKGROUND This study was undertaken to determine the relationship between traumatic rupture of the thoracic aorta (TRA) and the direction of impact at the time of motor vehicle crash. METHODS Retrospective review of TRA patients from two different databases over a 4.5-year period (January 1, 1991 to June 30, 1995): (1) Ontario Coroners Office records of motor vehicle deaths from Metropolitan Toronto, and (2) the trauma registries of Sunnybrook Health Science Centre and St. Michaels Hospital in Metropolitan Toronto. RESULTS Ninety-seven patients (81 from the coroners database and 16 from the adult trauma unit registries) sustained traumatic rupture of the thoracic aorta. Forty-eight cases (49.5%) were a result of lateral impact crashes. Twenty-eight drivers (22 ipsilateral and six contralateral) and 20 passengers (16 ipsilateral and four contralateral) sustained TRA from lateral impact crashes. Ninety-one TRAs (94%) occurred at the peri-isthmic region. CONCLUSION Lateral impact crashes are a significant cause of TRA. Traumatic rupture of the aorta should be considered with a high index of suspicion after serious lateral impact crashes, just as physicians now consider patients at high risk of TRA after serious frontal impact crashes.

High-volume, high-pressure pulsatile lavage during cemented arthroplasty.

To determine the efficacy of high-volume, high-pressure pulsatile lavage in the prevention of cardiopulmonary dysfunction and fat embolism during cemented arthroplasty, we studied twenty-eight mongrel dogs that had had a bilateral cemented arthroplasty. Significant increases in pulmonary-artery pressure and pulmonary vascular resistance, accompanied by decreases in arterial oxygen tension and increases in intrapulmonary shunt fraction (Qs/Qt), characterized cardiopulmonary dysfunction after bilateral cemented arthroplasty when no lavage was used. Low-volume, low-pressure manual lavage did not significantly alter these physiological changes, but there was a significant reduction in the number of fat emboli that were demonstrated in the lungs as compared with the no-lavage group. High-volume, high-pressure pulsatile lavage of the intramedullary cavity after reaming significantly reduced the changes in pulmonary-artery pressure, pulmonary vascular resistance, arterial oxygen tension, and intrapulmonary shunt fraction (Qs/Qt). In the pulsatile-lavage group, the number of fat microemboli that were found in the lungs was reduced to 25.7 per cent of those found in the no-lavage group. We concluded that meticulous high-volume, high-pressure pulsatile lavage reduces both pulmonary physiological derangements and fat emboli during bilateral cemented arthroplasty in dogs.