The Coventry Award. The effects of shelf life on clinical outcome for gamma sterilized polyethylene tibial components.

Tibial component shelf life was examined as a contributory factor of the in vivo failure of gamma sterilized prosthetic knee replacements. One hundred eighty-eight Synatomic total knee replacements sterilized by gamma irradiation in air were implanted by one surgeon into 147 patients between May 1985 and December 1994. Of these, 135 knees in 105 patients with a mean followup of 5.8 years (range, 2.1-11.3 years) were included in the study. The mean shelf life of the implants was 3.6 years (range, 0.1-10.7 years). Clinical failure for this study was defined as component retrieval resulting from polyethylene degradation. The knee components were divided into three different groups determined by their shelf storage durations of 0 to 4 years (Group 1, 93 components), between 4 and 8 years (Group 2, 21 components), or greater than 8 to 11 years (Group 3, 21 components). Six prostheses were revised because of polyethylene degradation after a mean implantation time of 2.5 years (range, 1.1-3.8 years). The mean shelf life of these six prostheses was 8.4 years (range, 5.8-9.6 years). Five years after implantation, prostheses that had shelf lives of less than 4 years had a 100% survival rate. Those that had shelf lives of 4 to 8 years before implantation had an 88.6% survival rate, and those prostheses that had shelf lives greater than 8 to 11 years had a 79.2% survival rate.

Hook of the hamate fractures in athletes.

Five patients have been treated for six hook of the hamate fractures over the past 8 years by the authors. Of these, four patients were professional baseball players and one patient was an accountant. All fractures occurred while playing baseball; four while swinging a bat, and two secondary to a fall on an outstretched hand. Roentgenographic diagnosis was made by carpal tunnel view alone in two, oblique and carpal tunnel view in one, bone scan and subsequent carpal tunnel view in two, and computerized tomography in one fracture. Five of the fractures were through the base of the hook, while one was toward the tip. All patients ultimately underwent hook resection, four early and two late. The patient who sustained the tip of the hook fracture underwent resection of the fracture only to refracture the same hook at its base 6 months later. All patients returned to their previous level of activity in 6 to 8 weeks after surgery without loss of function. Hence, it is the authors' opinion that the entire hook should be resected to the base of the hamate as the primary form of treatment in hook of the hamate fractures.

Lumbar spinal stenosis. A cause of continued pain and disability in patients after total hip arthroplasty.

Eight patients, all with continued posterior hip pain following total hip arthroplasty, were seen during a 15-month period. In each patient, that pain and other disabling symptoms were traced to a degenerated, stenotic lumbar spine. The relationship of lumbar stenosis to degenerative hip disease is presented. Myelography was used to diagnose the stenosis in all patients, and findings were confirmed at laminectomy. Wide decompressive laminectomy and partial facetectomy was followed by complete relief of pain and other disabling symptoms in the 6 patients who were able to undergo it.