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Biomedical subjects

J G Sallis

Publications and source records attributed to J G Sallis.

5 recordsLinked to original sources
PubMed1989

Recruiting survey respondents to mailed surveys: controlled trials of incentives and prompts.

Three controlled experiments tested the efficacy of 1) a postcard or telephone prompt, 2) a lottery, 3) monetary incentives, and 4) questionnaire length to recruit adult survey respondents to a random sample of residences in San Diego, California, during 1986-1988. In experiment 1, the group randomly assigned to receive a telephone call prenotification plus the lottery incentive responded 26-66% more frequently than did controls (p = 0.02) after a single mailing. The postcard plus lottery was 17-54% more effective than no intervention with controls (p = 0.05). A second mailing of the survey weakened these effects. In experiment 2, the group randomly assigned to receive a two-page survey with the lottery announcement responded 69% more frequently after one mailing (p = 0.03) and 53% more frequently after a second mailing (p = 0.04) than the group that received an eight-page survey without the lottery incentive. The shorter form alone or the lottery alone did not increase response rates significantly relative to the long form without a lottery. In experiment 3, a monetary incentive of $5.00 contingent on response to the second mailing of the survey increased the rate of response from initial "nonresponders" by 100% relative to control who received no incentive (p = 0.03) and 75% over those who received $1.00 not contingent on response (p = 0.04). Little sampling bias and no reactivity was attributable to the recruitment procedures.

Adult↗
PubMed1989

Assessing fibular length using bimalleolar angular measurements.

Shortening of the fibula after fracture is common and often difficult to appreciate. Loss of lateral malleolar anatomy causes significant biomechanical changes in the ankle and correlates with poor clinical results. We studied angular measurements of distal fibular length to serve as a guide for assessing fibular reduction after ankle fracture. Mortise view X-rays of 50 normal ankles from 25 healthy volunteers were obtained. The average talocrural angle measured 78.5 degrees. However, individual variation was high with values ranging from 75 to 86 degrees. Comparing contralateral ankles demonstrated an average difference of 1.3 degrees (range 0 to 4 degrees). A new, simpler bimalleolar angle was devised which compares the long axis of the fibula with a line drawn between the tips of the malleoli. The average bimalleolar angle measured 77.8 degrees (range 72 to 86 degrees). The contralateral difference averaged 1.2 degrees (range 0 to 3 degrees). This angle was simpler to use and more reproducible. Angular measurements were tolerant of usual radiographic techniques. Internal or external rotation of the ankle up to 5 degrees caused an insignificant change in the angular measurements. One degree change in the talocrural or bimalleolar angle was found to correspond with a 1 mm change in fibular length for the average ankle, calculated radiographically and confirmed in a cadaver study. Abnormal fibular shortening is detected with an angular difference between injured and contralateral sides of 3.0 degrees using the talocrural angle or 2.5 degrees using the bimalleolar angle (95% confidence limits). Thus, a 2.5 to 3.0 degrees contralateral difference should serve as a minimum value required to direct a change in therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Pain after total knee arthroplasty caused by soft tissue impingement.

The usual causes of pain after total knee replacement are well known, but there are a small number of patients in whom its aetiology is obscure. We report three patients with a specific pain syndrome caused by hypertrophic fibrous tissue in the intercondylar notch. Excision of this tissue relieved the symptoms completely.

Humans↗
PubMed1985

A modified technique for the fixation of pathologic fractures in the lower femur.

Intramedullary nail fixation augmented by the pressure injection of methylmethacrylate was investigated by use of bovine femora. In this technique, the nail is first placed in its final desired position; cement is then injected with a conical-tipped syringe through a distal drill hole into the medullary canal around the nail. This method was compared with the conventional technique of first placing the cement into the medullary canal and then driving the nail into position. Calf femora were used to compare the cement pressures generated, the shear resistance at the bone/cement interface, and the contour of the endosteal cement surface produced by the two cementing techniques. Significantly higher bone/cement interface pressures were generated by the injection of cement. Shear resistance at the bone/cement interface, investigated by push-out tests, revealed no significant difference between the two techniques. Dissolution of the specimens in nitric acid produced a methylmethacrylate cast of the endosteal surface, thus revealing the pattern of cement penetration into endosteal bone. The cement surfaces made by the injection of cement revealed characteristics of superior fixation and penetration compared to those made by the conventional method. The injection of cement for pathologic long-bone fractures is safer than the conventional method, is less susceptible to intraoperative complications, and offers satisfactory fixation.

Bone Cements↗