Transient bilateral sensory and motor symptoms after trauma, including complete paralysis, have been identified in patients with cervical spinal stenosis. Radiographs of 23 patient athletes with cervical spinal neurapraxia were used for measurement of the cervical spinal canal. Two methods of measurement were used. In the conventional method, sagittal diameter is measured from the posterior surface of the vertebral body to the nearest point of the corresponding laminar line. In the ratio method, the sagittal diameter of the spinal canal is divided by the sagittal diameter of the corresponding vertebral body. Results indicate the ratio method is reliable for determining cervical spinal stenosis and is independent of technical factor variables.

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Because bacterial adhesion is an important predisposing factor in the development of clinical implant infection, tantalum may offer benefits as an adjunct or alternative material compared with current materials commonly used for orthopedic implants.

Dislocation following hip arthroplasty remains problematic. While the etiology of dislocation may be multifactorial, implant system design may play a role. Using a computer aided design program, virtual range of motion of several commonly implanted designs was performed with prosthetic interference representing impingement used as an endpoint. Implants with small diameter head size (22 mm) and a larger trunion geometry (type II taper) demonstrated impingement in flexion at less than 90 degrees , suggesting an increased risk for dislocation. To investigate this clinically, we performed a review of a consecutive series of 254 primary hip arthroplasties performed by a single surgeon using an implant with a type II taper (Biomet, Warsaw, IN). At a minimum 2 year followup, 12 patients with 12 hips (4.8%) had at least one episode of dislocation. Stratified by head size, the dislocation rates were 3.6% for 28 mm, 4.8% for 26 mm, and 18.8% for 22 mm bearings. These findings support the notion that computer aided design modeling of implant systems is useful in evaluating range of motion and this technique could be employed during the design of any new implant system.