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S Arms

Publications and source records attributed to S Arms.

7 recordsLinked to original sources
PubMed1995

Effect of anterior cruciate ligament reconstruction with patellar tendon or prosthetic ligament on the morphology of the other ligaments of the knee joint. An experimental study in dogs.

The effect of anterior cruciate ligament replacement on the other ligaments of the knee, including the medial or lateral collateral and posterior cruciate ligaments, was studied histologically in the canine knee. The anterior cruciate ligament was replaced either with the medial third of the patellar tendon or with a prosthetic ligament. Histologic analysis was performed 3 months after prosthetic ligament implantation and 1 year after patellar ligament reconstruction. In all ligaments, numerous pathologic alterations were found. Degenerative changes such as glycosaminoglycan accumulation, metachromasia, collagenolysis, collagen necrosis, and lipomatosis were similar after 3 months and after 1 year. Granulation tissue, a sign that characterizes tissue repair, was seen only in those ligaments taken 3 months after anterior cruciate ligament surgery. Similar degenerative changes also were found in the ligaments of the knees with only a large medial arthrotomy (sham). In the contralateral control knees, the pathologic alterations were rare. Thus, open arthrotomy alone or with anterior cruciate ligament reconstruction seems to result in longstanding degenerative changes in all ligaments of the canine knee joint.

Animals↗
PubMed1988

Strain in the lateral ligaments of the ankle.

Strain was measured in the normal anterior talofibular ligament (ATF) and the calcaneofibular ligament (CF) using Hall effect strain transducers in five cadaveric ankles. These measurements were made in both ligaments with the ankle in neutral position and with the foot moving from 10 degrees dorsiflexion to 40 degrees plantarflexion in an apparatus that permits physiologic motion. The ankle ligaments were then tested with the foot placed in six different positions that combined supination, pronation, external rotation, and internal rotation. In the neutral position, through a range of motion of 10 degrees dorsiflexion to 40 degrees plantarflexion, the anterior talofibular ligament underwent an increasing strain of 3.3%. No significant strain increase was found with internal rotation. The only significant difference from the strains at the neutral position was in external rotation, which decreased strain 1.9%. In all positions, increased strain occurred with increased plantarflexion. The calcaneofibular ligament was essentially isometric in the neutral position throughout the flexion arc. The calcaneofibular ligament strain was significantly increased by supination and external rotation. However, with increasing plantarflexion in these positions, the strain in the calcaneofibular ligament decreased. Therefore, plantarflexion has a relaxing effect on the calcaneofibular ligament. Thus, the anterior talofibular and calcaneofibular ligaments are synergistic, such that when one ligament is relaxed, the other is strained and vice versa.

Adult↗
PubMed1983

Strain measurement in the medial collateral ligament of the human knee: an autopsy study.

A strain transducer was developed which employs a magnetic field sensing device to detect linear displacement. The transducer was attached to the medial collateral ligament (MCL) of human autopsy specimens, minimally influencing their physiologic behavior. A strain 'map' of the MCL as a function of knee flexion (full extension to 120 degrees) both with and without abduction force was obtained. Our investigation revealed consistent differences in the strain patterns between proximal, middle and distal segments of the anterior and posterior borders of the MCL. Anatomic variations in the pattern of collagen fibers within the MCL, interactions between posterior oblique capsular fibers and the MCL, and the skeletal configuration may account for these varied strain patterns.

Humans↗
PubMedDate not supplied

An in vivo analysis of the effect of transcutaneous electrical stimulation of the quadriceps and hamstrings on anterior cruciate ligament deformation.

Transcutaneous electrical muscle stimulation (TEMS) has been advocated as a method to rehabilitate the postoperative ACL repaired/reconstructed lower extremity. Isolated quadriceps contraction can potentially disrupt the ACL repair/reconstruction; to minimize this risk simultaneous quadriceps and hamstring stimulation has been used. This study measured the in vivo deformation of the ACL during TEMS of the quadriceps and hamstrings. Six legs in four Rhesus monkeys were immobilized in 0 degrees, 45 degrees, and 90 degrees of flexion in neutral rotation using a Hoffman frame and pins placed through the proximal femur and distal tibia. The hamstrings and quadriceps muscles were stimulated with a dual channel electrical stimulator individually and simultaneously at each point of flexion, and ACL deformation was measured using a Hall effect device placed on the anterior medial fibers of the ACL. The following conclusions were made: 1) Isolated quadriceps contraction produces ACL elongation at 0 degrees and 45 degrees of knee flexion and produces ACL shortening at 90 degrees of knee flexion. 2) Isolated hamstrings contraction produces ACL shortening at 45 degrees and 90 degrees of knee flexion and negligible effects at full knee extension. 3) It is not possible to simultaneously contract the quadriceps and hamstrings using separate stimulator pads for each muscle group. 4) At 45 degrees of knee flexion when the quadriceps muscles are stimulated before the hamstring muscles and simultaneous contraction of both is then sustained, ACL lengthening occurs. 5) When the hamstring muscles are fired before the quadriceps muscles and simultaneous contraction of both is sustained, ACL shortening occurs.

Animals↗