Moheb S. Moneim

Two potential causes of EPL rupture after distal radius volar plate fixation.

Rupture of the extensor pollicis longus tendon can occur after volar plate fixation of dorsally comminuted distal radius fractures. We attempted to identify the etiology of extensor pollicis longus tendon injury after volar plate fixation of the distal radius and potential solutions to this problem. After describing two case reports, we examine six cadaveric specimens and retrospectively review 10 selected patients to evaluate possible technique refinements to minimize damage to the extensor pollicis longus tendon during volar plating of the distal radius. We identify specific screw holes in three commercially available volar distal radius plates that direct the drill bit or prominent screw tips into the third extensor compartment. In addition, after reduction and plate fixation, bone fragments or dorsal gapping may predispose the extensor pollicis longus tendon to injury. We recommend either using shorter screw lengths or leaving the implicated plate holes unfilled. In addition, we suggest consideration of an open assessment of the third extensor compartment, if indicated, as performed through a small dorsal incision ulnar to Listers tubercle.Level of Evidence: Level III, Therapeutic Study. See the Guidelines for Authors for a complete description of levels of evidence.

Rapid prototyping: the future of trauma surgery?

Surgeons frequently must perform delicate surgery without the benefit of a firsthand look at what they will be operating on. Fracture orientation can be difficult to conceptualize, especially in the acetabulum or spine. Anatomic reduction and stable fixation remain a challenge and have required long incisions with wide exposure, sometimes with increased postoperative morbidity1-9. The inadvertent penetration of screws into the hip joint, during the treatment of both complex acetabular fractures and posterior wall pelvic fractures, has been well documented10,11. Successful surgical correction of deformities of the hip joint before the onset of osteoarthritis requires accurate characterization of the anatomic deviations from normal as the first step in the planning of a corrective osteotomy. Pedicle screws inserted with a standard surgical technique have sometimes penetrated the wall or even missed the pedicle12-20. Diagnostic techniques such as radiography, computed tomography, and magnetic resonance imaging provide only two-dimensional images of fractures and may not depict subtle fractures. Advances in radiology combined with advances in computer technology have made the three-dimensional representation of anatomic structures in living subjects easily obtainable. With use of modern rapid prototyping techniques, computers can now accurately reproduce three-dimensional models of actual osseous anatomy, which can be invaluable for understanding the characteristics of the fracture, for preoperative contouring of plates, and for selection of screw trajectories. The surgical precision that is possible with use of computer image guidance for placement of screws or pins about the hip joint for the treatment of complex acetabular fractures and for insertion of pedicle screws is impressive1,2,21-27. However, this technology is not yet commonly used by surgeons because of its apparent complexity. Easy fabrication of accurate three-dimensional models of the osseous anatomy, easy …

Mechanics of retrograde nail versus plate fixation for supracondylar femur fractures

Summary: Two common types of internal fixations for the supracondylar femur fractures—the retrograde intramedullary nail and the 95° sideplate and screw—were mechanically tested in synthetic composite femur bones to determine the quantitative differences in their inherent rigidity. The medial and lateral femoral condyles were separated by a sagittal osteotomy, and a standardized medial segmental shaft defect was created at the distal shaft. The osteotomized specimens were stabilized using one of the two implants and were tested in different modes of loading. The bending stiffness of both constructs were not significantly different in varus compression, medial bending (pure varus), and bending in flexion. The plate and screw implant was three times stiffer in lateral bending (pure valgus) and 1.2 times stiffer in valgus compression than the retrograde supracondylar nail (p<0.01). The torsional stiffness of the plate and screw implant was significantly higher, 1.6 times that of the nail. Clinically, the most important and common cause of implant failure is varus loadings due to loss of medial cortical contact. Although the retrograde nail was less rigid in other physiologically less critical modes of loading, it had a rigidity comparable to that of the plate in varus loading. Therefore, a supracondylar nail may be considered a mechanically possible alternative to plate fixation.

Latissimus dorsi muscle transfer for restoration of elbow flexion after brachial plexus disruption

Five patients between 10 and 46 years old were reviewed after a latissimus dorsi muscle transfer to restore elbow flexion. Loss of elbow flexion resulted from traumatic brachial plexus paralysis in all five patients. All had some weakness in other muscle groups in the upper extremity. The follow-up period was from 25 to 68 months (average = 39.4 months). A range of motion of 0 degrees/115 degrees, 10 degrees/100 degrees, 0 degrees/110 degrees, 0 degrees/70 degrees was obtained. After the transfer, three patients could supinate the forearm, and supination of 90 degrees, 15 degrees, and 10 degrees was measured. Two patients could lift 4 lb, while two others could lift 1 and 1.5 lb, respectively. Evaluation of activities of daily living by a standardized test revealed disappointing results. The two patients with less than 90 degrees elbow flexion had initial paralysis of the latissimus dorsi muscle at the time of injury. This procedure should not be done unless the latissimus dorsi muscle is normal.

Comparative fatigue strengths and stabilities of metacarpal internal fixation techniques

To study quantitative differences in the fatigue strength and stability obtained with 5 types of internal fixation of metacarpal fractures, 105 preserved human metacarpals were cyclically tested in bending, torsion, and axial loading after oblique osteotomies of the metacarpal and internal fixation. The dorsal plate with lag screw was superior in all modes, followed by the two dorsal lag screws, crossed Kirschner wire tension banding, and intramedullary Kirschner wire fixation. The five intramedullary and the paired intramedullary Kirschner wire fixations were not statistically different. The fatigue life of the plate fixation was significantly larger in bending (1.5 times), torsion (1.6 times), and axial loading (2.5 times) than the second strongest fixation, two dorsal lag screws. Its initial rigidity was significantly higher in axial loading (1.5 times) but was not statistically different in bending and torsion.

Radiocarpal dislocation--classification and rationale for management.

Radiocarpal dislocation is a rare injury. The authors reviewed seven cases with this injury and identified two groups of patients. Type I involves a dislocation of only the radiocarpal joint, while Type II involves intercarpal dislocation also. Four patients were included in Type I dislocation (3 dorsal and 1 volar). The other three patients had Type II dislocations, all of which were volar dislocations. Two patients had evidence of injury to the median and ulnar nerves at the time of the injury and both recovered completely. Closed reduction was possible with good results in three patients with Type I dislocation. All patients with Type II dislocation required open reduction and all had residual problems. The distinction between Type I and Type II is essential in order to evaluate the full extent of the injury. Closed reduction should always be attempted in Type I dislocation. Type II dislocation should be treated by open reduction and repair of all torn ligaments.

Isokinetic dynamometric technique for spasticity assessment

Firoozbakhsh KK, Kunkel CF, Scremin AME, Moneim MS: Isokinetic dynamometric technique for spasticity assessment. Am J Phys Med Rehabil 1993;72:379–385.This study was conducted to determine the feasibility of quantifying spasticity by measuring the resistance to passive movement using an isokinetic dynamometer. A quantifiable method was developed by determining the summation of the four consecutive resisting torque amplitudes during flexion and extension of the knee at specified speeds and range of motion. A more rigorous assessment was made by finding the slope of the linear regression curve of torque-velocity data. Although the values of maximum torque were higher in the spastic group than in the normal group, the difference was statistically significant only when the sum of the torque amplitudes was considered (P < 0.0028). Values of the maximum torque as well as the sum of the torque amplitudes increased in a linear fashion (r > 0.75) with increasing velocity. The slopes of the torque-velocity curves were greater in spastic subjects than in normal subjects. The sensitivity to the rate of stretch was statistically greater (P < 0.0004) for the spastic group than normals only when the sum of torque amplitudes was considered. The corresponding data obtained during the flexion and extension of the knee were not statistically different (P > 0.05). Serial summation of torque amplitudes and measurement of slope in the torque-velocity curve are sensitive and repeatable methodologies for the measurement of spasticity assessment.

Coracoid fracture as a complication of surgical treatment by coracoclavicular tape fixation. A case report.

In a 22-year-old man surgically treated for acromioclavicular dislocation, coracoid fracture was caused by bone failure at the Mersaline loop. The addition of bony erosion between the two drill holes in the clavicle caused the tape to loosen and the deformity to recur. Postoperative infection may also have played a role in causing the coracoid fracture. When tape is used, it should be passed around the clavicle, not through it. If the deformity recurs, coracoid fracture should be suspected.

New Mexico rattlesnake bites: demographic review and guidelines for treatment

The demographic features, treatment, and outcome of 36 rattlesnake envenomation cases are reviewed. Two populations at special risk are identified: (1) young children (12/36) who sustain lower extremity bites, and (2) adults who consume alcohol and handle snakes (10/36) who sustain upper extremity bites. Antivenin was used in 22 cases with only one serious case of serum sickness. Three definite diagnoses of compartment syndrome were made on the basis of elevated compartment pressures. Hand bites accounted for 20 of the 36 cases. The greatest functional disability followed digit bites in that 11 patients developed decreased motion and sensation. The indications for fasciotomy and debridement are discussed, both for digit and non-digit envenomations. General treatment recommendations are given.

Transscaphoid perilunate fracture-dislocation: result of open reduction and pin fixation

Sixteen patients with 17 transscaphoid perilunate fracture-dislocations were treated by open reduction and pin fixation. Open reduction was performed through a volar approach in only one wrist, a dorsal approach in nine wrists, and combined volar and dorsal approaches in seven wrists. Primary bone grafting was performed in four patients. The follow-up period was from five months to eleven years and two months, with an average of 2.69 years. Seven patients had median nerve injury and all recovered. Of the 17 wrists, the scaphoid fracture healed in 15. This injury should be treated by early open reduction through a dorsal incision and pinning of the scaphoid fragments in an anatomic position. Avascular necrosis of the proximal fragment is not an indication for further surgery as long as the fracture is well reduced with evidence of healing. This replacement of necrotic bone by new bone requires several years. Primary bone grafting is unnecessary.