Biomedical subjects
Publications and source records attributed to M G Ehrlich.
Compression plates provide a reliable method for stabilizing subtrochanteric osteotomies (and fractures when indicated) in children. Apart from a standard compression set, no special appliances are required. The hazards and inconveniences of nail plates and external fixation devices are avoided.
In advanced osteoarthritis, all of the cartilaginous components are lost from the joint surface. Although mechanisms exist for proteoglycan degradation, there is not known to be any system for removal of the collagen. This study suggests that the loss of the collagen components may be a function of articular cartilage collagenase. The enzyme in normal human cartilage is bound to an inhibitor and appears to be present in very small amounts. Attempts to demonstrate collagenase activity in ground human articular cartilage or in its lysosomal fraction were unsuccessful. 7-Day cartilage tissue cultures also failed to demonstrate the presence of the enzyme; but the same culture fluid, incubated with trypsin, showed significant degradation of collagen, suggesting that trypsin destroyed the inhibitor. 7-Day culture fluids were then chromatographed on a heparin-charged Sepharose 4B affinity column that had been activated with cyanogen bromide. This removed the inhibitor, and the chromatographed fluid from osteoarthritic cartilage released 42% of the incorporated counts of the collagen substrate, whereas normal cartilage released 10.1% and a trypsin control, 6.4%. Electrophoresis of the degradation products of the enzyme-collagen complex incubated at 37 degrees C revealed breakdown was complete to small dialyzable fragments, while at 25 degrees C larger fragments were split off.
Section of the medial collateral and both cruciate ligaments combined with resection of the medial meniscus in rabbit knees caused instability and during the ensuing six months these knees showed progressive histological changes similar to those of human osteoarthritis. Biochemical analysis of the cartilage from such knee joints demonstrated a decrease in proteoglycan, an increase in acid phosphatase, and increases in the rates of synthesis of protein and glycosaminoglycan. These findings, which are quite consistent with those in human osteoarthritis, suggest that this animal model may be of value in the study of the pathogenesis and treatment of human disease.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Articular cartilage collagenase activity was determined for 28 sections obtained from twelve femoral heads. For each one square centimeter area, a section was graded by a histologic-histochemical grading system for the severity of the arthritis. Collagenase activity was found primarily in those areas of moderately severe disease, but not in mild or end stage arthritis.
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Thirty-eight cases of musculoskeletal pain in a pediatric population that defied diagnosis are reviewed. The time between the onset of symptoms and the final diagnosis averaged 11.4 months, but in many cases was greater than 1 year. The most common diagnoses included reflex sympathetic dystrophy, osteoid osteoma, osteomyelitis, intraarticular hemangiomata, slipped epiphyses, and rheumatoid variants. There were several uncommon causes of pain, such as soft tissue hemangiomata, dystonia, and Addison disease. The pitfalls and causes of error are reviewed.
There is, as yet, no successful replacement for a completely damaged physis. In a test of the usefulness of allograft replacement of the plate, growth plate chondrocytes were transplanted to a defect in the proximal tibial growth plate. The defect remained after resection of a bony bridge that was created in rabbits. Seven of 10 rabbits at 3 weeks and six of 8 rabbits at 6 weeks after transplantation showed resumption of growth and prevented progression of the tibial deformity. Killed epiphyseal cells, on the other hand, were rapidly replaced by bone. It is not clear whether the transplanted live cells actually grew or served as a living, but inert filler.
We studied a model of pin protrusion in rabbit hips to determine if chondrolysis is produced. Enzymatic degradation of the articular cartilage remote from the pin site and mechanical destruction of the acetabulum occurred. Loss of proteoglycans in the articular cartilage averaged approximately 30%, and matched the increase in neutral protease activity. This presumably accounts for the loss of height that occurs in chondrolysis, but throughout the study, the joint space did not narrow; instead, it increased. This suggests that some other factor is needed to produce chondrolysis, such as a slip or an immune response.
One hundred twenty-eight skeletally mature New Zealand White rabbits were used to study the effect of a single corticosteroid injection on the biomechanical, biochemical, and histologic aspects of ligamentous healing. Two steroid dosages were used. The amount of the low-dose steroid was calculated by determining the corticosteroid concentration at which fibroblastic synthesis of collagen was inhibited in vitro. A human equivalent dose of betamethasone was used as the high-dose steroid injection. These two steroid doses and a saline control were injected around a transected medial collateral ligament. At 10 days all groups showed significantly inferior biomechanical properties relative to noninjected controls. By 3 weeks the human equivalent steroid dose group continued to demonstrate significantly inferior properties. Histologic and biochemical analyses confirmed the biomechanical results. The clinical relevance of the study was that the delivery of a human equivalent steroid dose into an acutely injured ligament significantly impairs the healing process relative to a noninjected ligament at 10 days and at 3 weeks after injury. This implies that a corticosteroid-treated injured ligament may not be able to withstand the mechanical loads of early vigorous rehabilitation.
The control of postoperative pain in the pediatric orthopaedic patient is a challenging endeavor. Several studies have shown the efficacy of ketorolac tromethamine in the pediatric general surgical population, but its efficacy in the pediatric orthopaedic population remains unproven. Twenty-seven consecutive patients (age 6 months to 18 years) who underwent long-bone osteotomies or foot procedures by a group of three pediatric orthopaedic surgeons were given a ketorolac protocol (1 mg/kg loading, 0.5 mg/kg every 6 h for 24 h). Breakthrough pain was managed with morphine until the patient was able to take oral pain medication, as was any pain after the 24-h period for ketorolac expired. Thirty-seven age- and case-matched patients were used as retrospective controls. The patients in the study who received ketorolac required significantly fewer doses of morphine than did the control group (2.29 +/- 3.98 vs. 10.02 +/- 3.39; p < 0.05). In addition the patients on the ketorolac protocol experienced fewer gastrointestinal side effects (4% vs. 32%; p < 0.05). Finally, the patients in the ketorolac group had a significantly shorter length of stay (3.63 +/- 1.64 days vs. 4.74 +/- 1.76 days; p < 0.05). There were no bleeding complications in either group. Ketorolac is thus a safe and effective means of controlling postoperative pain in the pediatric orthopaedic population while avoiding the troubling maleffects seen with the exclusive use of morphine.
Three cases of Larsen's syndrome in siblings are presented to illustrate a paradigm for the age-related treatment of deformity. Each child presented at a different age, with differing degrees of deformity and growth disturbance. Both growth and remodeling potential influenced the choice of treatment and outcome. The surgeon who undertakes the correction or prevention of these deformities must face the problem of and, it is hoped, use, growth potential from open physes and the progressive loss of remodeling capacity with advancing age.
The effects of chondrodiatasis on chondrocyte division, matrix synthesis, and microcirculation in rabbit growth plate were studied. The procedure did not produce any significant change in the percentage of cells labeled with tritiated thymidine, the intensity of radioactive sulfate labeling of the matrix, or the blood supply of the physis. These findings suggest that the procedure does not work by stimulating cell division, synthetic function, or vascularity of the plate, but rather by stretching the matrix passively.
Longitudinal bone growth is the ultimate characteristic clinically desired from the physis. Measuring relatively short-term parameters in comparison with growth may help facilitate investigation of physeal reconstruction. We monitored the viability and metabolism of cartilage transplanted to physeal regions in rabbits. In addition to measuring growth, we performed histochemistry and autoradiographic studies. The results indicated that cartilage transplanted in an avascular fashion could remain viable, synthesize proteoglycan, and be associated with growth (although less than normal) relative to controls. Such measurements may be of benefit in pursuing the goal of clinical physeal reconstruction.