Archives of orthopaedic and trauma surgery
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Arch Orthop Trauma Surg · Jan 1990
Methods and applications of three-dimensional imaging in orthopedics.
Computed tomography is a commonly used technique for detecting pathological alterations in soft tissues and the skeleton. Three-dimensional images of the skeleton are very useful for planning surgical treatment and monitoring therapy, but unfortunately mental reconstruction of complex three-dimensional anatomical structures from conventional tomography is very difficult. This article describes a process by which automated analysis of the regions of interest in the computed tomographic (CT) images yields the contours of the surfaces which can be presented pseudo-three-dimensionally using Phong's lighting model and Gouraud's shading methods. Three applications in the areas of orthopedics and neurosurgery demonstrate the efficacy of the method.
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The spontaneous degeneration of the human rotator cuff seems to have mechanical and nutritive causes. Until now it was not known whether other species without an acromion had a vascularization of the rotator tendons which is similar to that of man. ⋯ Most important is the fact that the supraspinatus tendon shows an area of hypovascularity close to its insertion. Thus, the dog may be used for experimental purposes relating to the rotator cuff.
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Arch Orthop Trauma Surg · Jan 1990
Effect of direct-current stimulation on the growth plate. In vivo study with rabbits.
Electrical stimulation of 8 microA direct current was applied to the femoral distal growth plate of young rabbits for periods of 1, 2, and 3 weeks to examine the effect on bone growth. The results were analyzed using X-ray measurement, histological observation including tetracycline labeling, and glycosaminoglycans analysis. No obvious differences between the stimulated side and the control side were observed in the morphological and biochemical studies, but characteristic thickening of the growth plate caused by the accumulation of hypertrophic cells was found in the group stimulated for 2 weeks. Electricity affects the cell behavior of the growth plate, but it is necessary to find more appropriate conditions to stimulate obvious bone growth.
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Arch Orthop Trauma Surg · Jan 1990
Restoration of elbow flexion by latissimus dorsi myocutaneous or muscle flap.
Six patients with flail elbow as a consequence of brachial plexus injury or traumatic loss of arm muscles underwent bipolar transposition of latissimus dorsi myocutaneous or muscle flaps to the biceps brachii to restore elbow flexion. The muscle strength achieved was 1.5-2.5 kg and the total range of active excursion is about 95 degrees. ⋯ Elbow flexion of more than 120 degrees is necessary for the affected hand to reach the mouth and should be one of the goals of the operation. Versatile use of the myocutaneous flap facilitates skin closure and improves the contour of the arm.
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Animal studies can provide important information in the evaluation of new techniques and prosthetic designs in orthopedics. As a prerequisite they must parallel as closely as possible the human conditions they are modeling. An arthritic sheep model simulating the human clinical situation has previously been designed and reported by Phillips and Gurr. ⋯ Only one of the 12 cases showed postoperative avascularity of the femoral head. Radiologic follow-up and histologic examination showed features consistently and strikingly similar to those seen in human practice. The sheep hip with simulated arthritis provides a sensitive, clinically reproducible model for the future study of other arthroplasty types and problems.