"Floating knee" injuries: ipsilateral fractures of the femur and tibia.

Ipsilateral fractures of the femur and tibia have been called "floating knee" injuries and may include combinations of diaphyseal, metaphyseal, and intra-articular fractures. These are often high-energy injuries and most frequently occur in the polytrauma patient. Many of these fractures are open, with associated vascular injuries. Surgical stabilization of both fractures and early mobilization of the patient and the extremity produce the best clinical outcomes. The use of a radiolucent operating room table and the introduction of retrograde intramedullary fixation of femoral fractures have facilitated surgical stabilization of some floating-knee fracture patterns. Although treatment planning for each fracture in the extremity should be considered individually to achieve the optimal result, the effect of that decision must be considered in light of the overall injury status of the entire extremity. Collateral ligament and meniscal injuries may also be associated with this fracture complex. Complications (such as compartment syndrome, loss of knee motion, failure to diagnose knee ligament injury, and the need for amputation) are not infrequent. Better results and fewer complications are observed when both fractures are diaphyseal than when one or both are intra-articular.

Patellar ligament reconstruction using allograft patellar ligament: a case report.

This report describes a method of patellar ligament reconstruction. Our patient sustained a rupture of the patellar ligament and had reconstruction with allograft patellar ligament after failed primary repair. At the 2-year follow-up, his range of motion was 0 degrees to 110 degrees and he was able to return to unrestricted standing work.

Tilted lateral radiographs in the evaluation of intra-articular distal radius fractures.

The anatomy of the distal radius confounds the assessment of fracture displacement of the lunate facet. Since reduction of the articular surface is paramount to obtaining good clinical results, this study was designed to evaluate whether a radiograph taken 22 degrees from true lateral (forearm held at a 22 degrees angle from the horizontal film cassette) would enhance the accuracy of measuring displacement. Fifteen lunate facet fractures of varying depression were produced in 7 fresh cadaveric wrists. Posteroanterior (PA), standard lateral, and 22 degrees tilted lateral radiographs were obtained of each fracture pattern. Four observers reviewed the films and measured the depression of the fragments from their anatomic position. Measurement error from actual depression averaged 1.1 mm when the evaluators evaluated the 22 degrees lateral and PA films, 1.5 mm for the standard lateral and PA views, and 0.8 mm for the standard lateral, 22 degrees lateral, and PA radiographs (combined group). The decrease in measurement error obtained from all 3 groups was statistically significant. The results of this study suggest that the 22 degrees tilted lateral, either in combination with the standard lateral radiograph or just with the PA view, may help the hand surgeon better understand the intra-articular depression of lunate facet fractures of the distal radius.

Abducted, hyperextended small finger deformity of nonneurologic etiology.

The abduction and hyperextension deformity of the small finger is usually associated with ulnar nerve palsy. Six patients who sustained an abduction force to their small finger presented with the finger in an abducted and hyperextended position. All patients were neurologically intact and were unable to adduct or flex the finger at the metacarpophalangeal joint. Surgical findings in these patients included rupture of the radial sagittal band, collateral ligament, and junctura tendinum. Sequential division of these structures in cadaveric hands confirmed that all these tissues had to be deficient for this deformity to occur. The traumatic abducted, hyperextended small finger deformity may respond to conservative treatment, but surgery is sometimes necessary.

Mechanical comparison of plates used in the treatment of unstable subtrochanteric femur fractures.

OBJECTIVES: To determine the stiffness and strength characteristics of certain plate-composite femur models designed to simulate unstable subtrochanteric femur fractures (OTA 31-A2.3). DESIGN: Fifteen identical composite femora were osteotomized to produce like models of an unstable subtrochanteric femur fracture. The femora were fixed with either the Synthes 95 degree angled condylar blade plate, a 95 degree dynamic condylar screw plate (DCS), or a 135 degree dynamic compression hip screw (DHS). MAIN OUTCOME MEASUREMENTS: A materials testing machine was used to apply compression to the femoral head through an adapter plate. Stiffness values were calculated from the load-deformation curves obtained. RESULTS: The DHS-femur model was the stiffest (586 newtons/ millimeter), followed by the 95 degree DCS (404 newtons/millimeter) and the 95 degree condylar blade plate (260 newtons/ millimeter). The DHS also had the highest ultimate load-to-failure (4,877 newtons), followed by the 95 degree DCS (3,107 newtons) and the 95 degree condylar blade plate (2,272 newtons). All of these differences were statistically significant (p < 0.00001 ). CONCLUSIONS: Our findings suggest that the Synthes 95 degree DCS has greater stiffness and strength than the Synthes 95 degree condylar blade plate when tested in this model of an unstable subtrochanteric femur fracture. This model may not be completely appropriate for testing the 135 degree DHS because the hard plastic "cortex" of the model prevented cut-out of the screw.

Intramedullary fixation of unstable forearm fractures in children.

Although most forearm fractures in children are appropriately treated with closed reduction and cast immobilization, certain unstable fractures of the radius and ulna are best treated operatively. We present our technique of using flexible intramedullary fixation to stabilize these fractures. Retrograde fixation of the radius is obtained with a 5/64th or 3/32nd Steinmann pin, and stabilization of the ulna is achieved with a 1/8th inch Rush rod. Complications from this technique are few. The rods are usually removed after fracture union to avoid painful hardware.

Biomechanical comparison of hybrid external fixators.

OBJECTIVES: To determine the stiffness characteristics of the hybrid ring fixator in the treatment of (OTA 41-C) proximal metaphyseal and shaft tibial fractures. DESIGN: Five identical composite tibiae were fixed with a Synthes, ACE Fischer, Howmedica Monticelli-Spinelli, or Smith & Nephew Trauma Ilizarov hybrid external fixator or with the conventional Ilizarov wire fixator. The Synthes and Monticelli-Spinelli fixators were tested twice, the first time with the connectors on the outside of the ring and the second time with the connectors on the inside of the ring. MAIN OUTCOME MEASUREMENTS: A materials testing machine was used to apply pure compression, anterior and posterior bending, medial and lateral bending, and torsion. Stiffness values were calculated from the load deformation and torque angle curves. RESULTS: Overall, the Synthes and Monticelli-Spinelli fixators were the most rigid of the fixators when the wire-to-ring connectors were placed inside the ring. In general, the fixators were stiffest in axial compression and least stiff in posterior bending. Wire length had a significant effect on overall stiffness. CONCLUSIONS: This study suggests that the four hybrid external fixators in standard configuration have stiffness characteristics similar to those of the conventional Ilizarov fixator when used to treat proximal metaphyseal and shaft fractures of the tibia.

Acute compartmental syndrome from hematogenous osteomyelitis of the ulna.

Compartmental syndrome of the forearm in children is usually caused by fractures, soft-tissue damage, burns, or arterial injury. This report presents the case of a child who had compartmental syndrome of the forearm resulting from acute hematogenous osteomyelitis of the ulna.

A method to locate the radial digital nerve of the index finger.

The radial digital nerve of the index finger is susceptible to injury during penetrating trauma or elective release of the A1 pulley. The intersection of a line drawn down the midline of the index finger and the proximal palmar crease identifies the location of the radial digital nerve. This method of identifying the topography of the nerve should assist the surgeon in determining the likelihood of injury after penetrating trauma, and preventing injury during elective procedures.

Two open forearm fractures after airbag deployment during low speed accidents.

Automotive airbags effectively mitigate the impact of vehicular collision by absorbing and distributing a force that otherwise would be sustained by the occupants. To be effective, inflation must be instantaneous and sufficient to provide restraint to a moving body. Deployment of automotive airbags is a violent event that may cause injury to the occupants of the vehicle. This report describes two patients with severe, open radius and ulna fractures that were caused by airbag inflation during low velocity motor vehicle accidents. The degree of soft tissue injury and bone comminution in these patients was not fully appreciated until surgery. Orthopaedic surgeons should be aware of the explosive nature of airbag deployment and realize that the injury may be far greater than expected from a low energy motor vehicle accident.

Pathologic morphology of the dislocated proximal femur in children with cerebral palsy.

We describe the gross and microscopic anatomic changes in the hip that result from the deforming forces in children with neuromuscular imbalance. Twelve dislocated proximal femora that had been resected from children with spastic diplegia or tetraplegia were evaluated with respect to their gross, microscopic, and radiographic structure. The epiphyses were wedge shaped with deformation of the femoral head apparent in all cases. In addition to a severe loss of articular cartilage, a furrowed erosion of epiphyseal bone suggested a sustained, blunt, band-like force across the surface of the hip where it opposed the acetabular labrum. The underlying physis of the capital femur was irregular with aberrant histologic structure, whereas that of the lesser trochanter was hypertrophic and angulated in a superior and anterior direction. A significant degree of valgus was not noticeable in most specimens. In summary, the spastic adductor and iliopsoas, responsible for the changes in the lesser trochanter, work in conjunction with the hip flexor and internal rotator muscles to subluxate the proximal femur. In the process, the superior rim of the acetabulum and capsule causes focal deformation of the superolateral femoral head, creating a fulcrum upon which the hip then progressively subluxates. The indentation locks the femoral head at the lateral acetabular margin, preventing complete dislocation, but leading to bone pain consequent to cartilage erosion.

Increasing prevalence of Kingella kingae in osteoarticular infections in young children.

Sixty children younger than 3 years with culture-positive hematogenous septic arthritis and acute/subacute osteomyelitis treated between 1990 and 1995 were reviewed to identify the infecting organism. Gram-positive bacteria were identified in 47 (78.3%) patients, and gram-negative organisms were identified in 13 (21.7%) patients. Haemophilus influenzae was cultured in none of the cases of septic arthritis and in only one (1.6%) case of acute osteomyelitis. Kingella kingae was cultured in 10 (16.7%) cases, with all of these patients between the ages of 10.5 and 23.5 months. Routine immunization of infants against H. influenzae has caused a change in the historically reported bacteria of bone and joint infections in children younger than 3 years. Haemophilus influenzae has lost its predominance as the most commonly identified gram-negative pathogen, and in this study, has been replaced by K. kingae.

Neurological deterioration after posterior wiring of the cervical spine.

Posterior cervical wiring is commonly performed for patients with spinal instability, but has inherent risks. We report eight patients who had neurological deterioration after sublaminar or spinous process wiring of the cervical spine; four had complete injuries of the spinal cord, one had residual leg spasticity and three recovered after transient injuries. We found no relation between the degree of spinal canal encroachment and the severity of the spinal-cord injury, but in all cases neurological worsening appeared to have been caused by either sublaminar wiring or spinous process wiring which had been placed too far anteriorly. Sublaminar wiring has substantial risks and should be used only at atlantoaxial level, and then only after adequate reduction. Fluoroscopic guidance should be used when placing spinous process wires especially when the posterior spinal anatomy is abnormal.

Myxoid liposarcoma of the retropatellar fat pad.

Soft-tissue sarcomas are rare lesions, and they are occasionally seen by the orthopedic surgeon. We describe the clinical history of a patient with a myxoid liposarcoma that arose from the retropatellar fat pad of the knee. The differential diagnosis of knee masses and the magnetic resonance image characteristics of myxoid liposarcoma are discussed. There are no previous reports of liposarcomas originating from the retropatellar fat pad. Given the consequences of inappropriate biopsy and surgery of suspected benign lesions, it is fundamentally important to adhere to the principles of musculoskeletal oncology in the evaluation of any soft-tissue mass that could be malignant.

MR artifacts after anterior cervical diskectomy and fusion: a cadaver study.

OBJECTIVE: To identify the source of metallic artifacts observed on cervical spine MR studies following anterior cervical diskectomy and fusion (ACD&F), preoperative and postoperative MR studies were done on cadavers using standard spin echo T1, T2, and GRASS imaging. MATERIALS AND METHODS: An ACD&F was performed on each cadaver at various levels using different combinations of drill burrs, curettes, and suction tips. RESULTS: Results showed that contact between the drill burr and suction tip produced the worst artifacts; however, artifacts still occurred in cases in which the suction tip was not introduced. CONCLUSION: This observation suggests that metal flakes from the curettes also produced artifacts. Image distortion was greater on GRASS imaging than on the spin echo imaging.