William C. Allen

The throw: biomechanics and acute injury:

The throw and its modifications are integral components of many sports. This study correlates case histories of acute injuries in throwing with a biomechanical analysis of the throw ing mechanism. Comparisons are made with a similar analysis of the kick analyzed by the same film technique and computer program. Just prior to ball release, the pitching arm extends through an arc of about 73 degrees in 40 msec, beginning with the elbow flexed at 80 degrees. This produces an axial load on the humerus and coincides with a pulse of external torque at the shoulder. This acts as stress protection to the humerus which is developing an internal torque of 14,000 inch-Ib prior to ball release. The change in angular velocity, or the angular acceleration, during the throw is acquired in a much shorter time than in the kick. Torque is directly proportional to angular acceleration. This necessitates the development of substantially higher torques in the humerus during the throw than about the knee during a kick. The kinetic energy in the arm is 27,000 inch-Ib during the throw. This is much higher than the kinetic energy in the kicking leg because the kinetic energy varies proportionally with the square of the angular velocity of the extremity. The angular velocity of the arm is about twice that of the leg. Thus, the pitching arm contains about four times as much kinetic energy as the kicking leg. These severe overload ing conditions predispose the upper extremity to injury in the throwing mechanism.

Primary iliopsoas bursography in the diagnosis of disorders of the hip.

The iliopsoas bursa is a well-defined anatomic structure that has been involved in various diseases about the hip, including osteoarthritis, rheumatoid arthritis, pigmented villonodular synovitis, and synovial chondromatosis. Demonstration of the iliopsoas bursa using contrast material has been reported during hip arthrography and inadvertently during angiography, but no direct or primary methods of iliopsoas bursography have been reported. A technique of primary bursography under fluoroscopy is described wherein filling of the bursa with contrast material allowed the observation of movement of the iliopsoas musculotendinous unit across the front of the pelvis during motion of the hip. This technique, which was of significant benefit in determining the etiology of two cases of the snapping hip syndrome of the internal variety, is simple, easily reproducible, and has clinical application.

The kick: biomechanics and collision injury.

an important element. The admixture of bony and soft tissue injuries suggests high energy mechanisms, and studies were done to explore the biomechanical factors involved. The objectives of this study were to (1) describe the motion of the lower extremity in the act of kicking a ball, (2) to define the magnitude and types of loads transmitted by the soft and hard structures about the knee, and (3) to obtain an appreciation of the potential for injury during such activity. The results of this study were correlated with the several case histories. CASE HISTORIES

Closed reduction and percutaneous stabilization of tibial plateau fractures.

Twenty-eight patients with tibial plateau fractures treated by closed reduction using forceful traction and percutaneous stabilization with pins or screws were reviewed. For six bicondylar fractures, transfixion pins with an external fixation device were used. In six cases, an arthroscopic exam was also done. For 21 patients, external support was used postoperatively. Twenty-one patients were followed an average of 26 months. All fractures healed. Functional ratings were: 14 excellent, 6 good, and 1 poor. Radiographic ratings were: 11 excellent, 9 good, and 1 fair. For fractures with large fragments without excessive comminution or severe central depression, this technique yields good results with minimal surgical morbidity.

The relationship between residency programs and fellowships in the educational setting.

In 1981, the Advisory Council for Orthopaedic Education published a list of 175 orthopedic postgraduate fellowships. Since that time, several groups within orthopedics have discussed various methods for enhancing the educational nature of fellowships as they related to orthopedic residency programs. The orthopedic community as a whole has concurred about the concept of accrediting fellowships, ensuring a minimum standard educational quality, and keeping the growth of fellowships in some areas from adversely affecting the educational quality of a residency program. When fellowships are accredited, standards are created, such as the requirement that a fellowship must last at least one year, and depending on the area of specialization, include both research and clinical work. Certification and accreditation are separate issues. Certification is the process of credentialing individual physicians as specialists and is the responsibility of a specialty board. Accreditation is the process of identifying residency and fellowship programs that meet published educational standards and is the responsibility of the Accreditation Council for Graduate Medical Education and the corresponding Residency Review Committee. There is little question that the educational process that occurs during a fellowship can have a beneficial effect on the learning process of residents and vice versa.

Post-traumatic catamenial sciatica.

This article presents a unique case of posttraumatic extrapelvic endometriosis presenting as a gluteal mass causing cyclic sciatica. A 38-year-old woman presented with an enlarging right buttock mass over the previous 6 years. She also had symptoms of radicular pain referred to the right leg and foot with sitting and daily activity. Four years prior to noticing the mass, she sustained a gunshot wound through the lower abdomen while 5 months pregnant. Excisional biopsy of the gluteal mass revealed endometrioma. Sciatica is a common and painful disorder that is believed to have an incidence of 40% in the adult population. Sciatica is most often due to intraspinal pathology affecting the lumbar nerve roots. There are many recognized extraspinal etiologies for sciatica in the literature including aneurysms, sciatic hernia, abcess, neoplasm, trochanteric wire, piriformis syndrome, ischial fracture, a posteriorly flexed uterus, and even an intrauterine device following uterine perforation. Similarly, endometriosis is a gynecologic condition that represents a significant health problem for women of reproductive age as it occurs in up to 50% of premenopausal women and 71% to 87% in women with chronic pelvic pain. Although rare, endometriosis has a well known ability to migrate outside of the abdominal cavity and proliferate ectopically under the control of systemic estrogen.

Fractures of the femur treated by intramedullary nailing using the fluted rod : a report of 193 consecutive cases

One hundred ninety-three of 196 acute nonpathologic femoral shaft fractures were treated consecutively with intramedullary nailing using the fluted rod. Closed intramedullary nailing was used in 126 fractures, and an open technique was used in 67. This series includes 58 open fractures and 104 comminuted fractures. All fractures treated with the fluted rod united. Complications included three superficial infections (1.5%). Malrotation greater than 20 degrees was noted in six patients (3.1%). Significant shortening (5 cm), which required treatment, occurred in one patient. After initial resuscitation and evaluation, routine treatment included preoperative traction and a first-generation cephalosporin followed by accurate reduction and nailing of the fracture. The results of this series suggest that the fluted rod may be ideal for the treatment of most femoral shaft fractures.