Biomedical subjects
Publications and source records attributed to J R Gregg.
Hunters and marksmen have some unusual seeing problems and they differ depending upon the type of gun--shotgun, rifle or pistol. A number of suggestions are made concerning prescribing for these individuals, especially presbyopes. Sighting techniques are discussed, including possible solutions to the difficulty created by crossed dominance.
Ten cases of isolated, complete paralysis of the serratus anterior muscle were diagnosed in young athletes during a three-year period. One patient had recurrent partial paralysis of the serratus anterior muscle, the first such case reported. From studies on cadavera and clinical observations, we concluded that paralysis of the serratus anterior muscle results from a traction injury to the long thoracic nerve of Bell. Since full recovery usually occurs in an average of nine months, surgical methods of treatment should be reserved for patients in whom function fails to return after a two-year period. Non-strenuous use of the involved extremity with avoidance of the precipitating activity, followed by exercises designed to maintain the range of motion of the shoulder and to increase the strength of associated muscles, is advocated for treatment of acute or repetitive injuries to the long thoracic nerve of Bell.
The composition and lipid profiles of the following tissues of the human knee joint were determined: articular cartilage, meniscus, ligaments, synovial fluid, synovium, intra-articular fat pad and bone marrow. The tissues were obtained from fresh cadavers and from surgical specimens. The lipid profiles of articular cartilage, meniscus and ligaments were similar to reported analyses of other tissues that are also rich in collagen. The lipid profiles for the remaining tissues were more like the profiles found in the fat depots and fatty tissues of the human body. Both the phospholipid and fatty acid patterns of these tissues were similar within statistical deviation. These results suggest that the per cent compositions of fatty acids and the phospholipid family profile ratios have limited range variability in the "normal" tissues of the human knee. On the other hand, the per cent neutral lipid compositions and their individual profiles showed great variations among the different tissue tissues of the knee.
Synovial fluid was analyzed for neutral fat globules using a modified Gurd test in 146 patients with various knee disorders. The presence of liquid neutral fat without an intra-articular fracture is an ominous sign of a significant soft tissue injury. Mechanically damaged knees contain neutral fat globules that are not found in normal or osteoarthritic knees. While liquid neutral fat may suggest a surgically amendable ligamentous and/or meniscal injury, 10% of the injured knees containing fat had an intra-articular fracture.
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A retrospective study of 80 patients with chronic slipped capital femoral epiphysis was performed, analyzing the clinical results with regard to pin placement and pin number. Follow-up averaged greater than 2 years, with 86% of the 80 patients obtaining a satisfactory clinical outcome. Serious complications occurred in 10 patients. The severity of complications increased as the number of pins used increased (p less than 0.07). A varus pin position resulting in a more inferior pin placement in the proximal femoral epiphysis was found to be associated with the fewest complications. When the pin tip avoided the superior and anterior quadrants in the proximal femoral epiphysis and was greater than 2.5 mm away from subchondral bone, the complication rate was decreased (p less than 0.003).
The purpose of this study was to evaluate anterior cruciate ligament reconstructions performed in adolescents with open physes and a skeletal age of at least 14 years. At one center, from 1992 to 1996, 19 adolescents (ages, 11 to 15 years) with open physes and a skeletal age of at least 14 years underwent arthroscopic anterior cruciate ligament reconstruction using an Achilles tendon allograft placed through drill holes across the open physes in both the distal femur and proximal tibia. Fifteen patients returned for reevaluation at an average of 25 months postoperatively (range, 12 to 60 months); the remaining four patients were interviewed by telephone. There were no significant leg-length discrepancies or angular deformities as determined by scanograms and anteroposterior and lateral radiographs of the femur and tibia. The mean Lysholm knee score was 97 (range, 94 to 100) and the mean KT-1000 arthrometer side-to-side difference at 20 pounds of anterior force was 1.7 mm (range, 0.0 to 3.0). All patients were satisfied with the results of surgery, and 16 of 19 patients returned to the same sport they were participating in before the injury. This study demonstrates that anterior cruciate ligament reconstruction using an Achilles tendon allograft is a viable treatment option for skeletally immature patients with a skeletal age of 14 years who have sustained midsubstance tears of the anterior cruciate ligament.
Sixty healthy, athletic children were treated on a Cybex II Dynamometer to obtain values for the relative strengths of the major muscle groups of the lower extremity. Prepubescent and postpubescent boys and girls were tested. Of the anthropometric parameters measured, lean body weight correlated best with maximal torque force development. In prepubescent children, the mean maximal quadriceps torque force, measured in foot-pounds at 60 deg/sec, is equal to 70% of the lean body weight. In postpubescent subjects, the mean peak quadriceps torque equalled 80% of the lean body weight in girls and 90% of the lean body weight in boys. Correlations can be established between the maximal torque force generated by the quadriceps and the strength of the hamstrings, ankle dorsiflexors, and plantar flexors. The values obtained are useful in planning training and rehabilitation programs and in determining when an injured young athlete can safely return to his or her sport.