Biomedical subjects
Publications and source records attributed to T Kiaer.
In a prospective study, we performed 18 core decompressions for Stage I primary osteonecrosis of the femoral head. Only 5 patients (six hips) seemed to have benefited from the intervention for more than 1 year.
Several regulatory mechanisms have been shown to influence the intraosseous circulation. The influence of general hypovolemia on bone circulation and possible regulatory effects were investigated by recording the intraosseous pressure and PO2 and PCO2 continuously by mass spectrometry in rabbits. Hypovolemia was induced by repeated bleedings. The intraosseous and arterial pressures were found to be linearly related. The intraosseous PO2 already decreased after the first step of bleeding and decreased more than 50% of the initial value after an average blood loss of 40 ml. The intraosseous PCO2 showed an opposite pattern. The experimental PO2 vs. arterial pressure curves were similar to curves obtained by a computer simulation that assumes the blood flow to be proportional to the intraosseous pressure.
The intra-osseous pressure, PO2, and PCO2 were measured in 32 hips (21 patients) which were painful but showed no severe degenerative changes. Pre-operative scintigraphy and radiography was performed in all patients. Thirteen hips showed early osteoarthritis, eight had early osteonecrosis, and 11 had no changes. Core biopsies were performed and the bone was examined histologically and graded for necrosis. Histologically, necrosis was present in 27 specimens. Scintigraphic findings did not correlate with the histological results but were more closely related to the radiographic findings. The intra-osseous pressure in hips with histological necrosis (mean 47 mmHg) was significantly higher than in hips without necrosis (mean 26 mmHg). The PO2 was lower in bone with histological necrosis (mean 44 mmHg) than in bone without (mean 71 mmHg). PO2 increased and intra-osseous pressure decreased after decompression. The results confirm that ischaemia plays a central role in the development of necrotic changes in bone. Histological necrosis was found in hips with radiographic signs of osteonecrosis and in those with osteoarthritis. Radiography, and scintigraphy are shown to be insensitive methods for differentiating between those disorders.
Fracture of the proximal humerus in children is rare. The records from 1976 to 1977 of 77 patients aged 0-15 years with a fracture or epiphyseal separation of the proximal humerus were reviewed. Totally, 64 of 72 patients had a follow-up examination (median observation time 9 years). Twenty-one children had an epiphyseal separation and 51 a metaphyseal fracture. All but 1 were treated conservatively. Seven had slight sequelae at follow-up, i.e., transient pain or minor restriction of motion. The rest were asymptomatic. Full remodeling of fractures left displaced occurred in all the cases. No avascular necrosis or shortening of the humerus were found. Nonoperative treatment is appropriate for proximal humeral fractures in children, even for those with extensive displacement.
The first reported case of an intraarticular malignant giant cell tumor of synovium studied with electron microscopic and immunohistochemical examination is presented, together with a case of diffuse intraarticular pigmented villonodular synovitis with extensive bone destruction. The malignant case was dominated by uniform cells positive for histiocytic markers, the fine structure showing a gradual change from cells dominated by organelles serving a secretory function to cells with phagocytic activity. The reported cases of giant cell tumor of the tendon sheath indicate that the pertinent histologic changes regarding malignancy are an increase in cell polymorphism and in the number of mitoses, and a decrease in the number of multinucleated giant cells.
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We have investigated the effect of joint tamponade and of traction in extension on the oxygen and carbon dioxide tensions in the femoral head of the immature goat, using mass spectrometry. Tamponade of 75 mmHg caused the oxygen tension in the femoral head to drop from 48 +/- 4 mmHg to 29 +/- 3 mmHg. Traction in extension further decreased the oxygen tension. Both these changes were highly significant. The partial pressure of carbon dioxide increased, but to a lesser extent and only effusion together with traction gave a statistically significant effect. Our study showed that joint effusion can produce hypoxia in the bone as a result of impaired blood flow to the femoral head. The application of traction increases this haemodynamic effect.
We interviewed 92 patients with nonoperatively treated tibial-shaft fractures with minimum of soft-tissue injury 20-39 years after the injury. Seventeen fractures had healed with an angular deformity exceeding 10 degrees. Seven patients with and 15 without symptoms, but with angular deformity exceeding 10 degrees, were examined clinically and radiographically. None of these 22 patients had arthrosis of the ankle. We concluded that angular deformity within 15 degrees will not lead to restricted motion, pain, or arthrosis of the ankle.
We recorded intraosseous pO2 in 9 patients with Garden Stage I fractures of the femoral neck during aspiration of the hemarthrosis. An increase in pO2 indicating restoration of the blood flow was seen in 2 of the patients.
We compared intraosseous pressure, partial pressure of oxygen and carbon dioxide, and histopathology in 10 hips with arthrosis and in seven hips with nontraumatic necrosis of the femoral head. Hypoxia of the subchondral bone was present in both conditions. In arthrosis the intraosseous pressure was normal, whereas intraosseous hypertension was present in necrosis. Partial pressure of carbon dioxide was normal in both conditions. Identical signs of subchondral medullary and trabecular necrosis were found in both conditions.
The joint cartilage is depending on the oxygen diffusing from the capillaries of the synovial membrane through the synovial tissue and synovial fluid. In the present study we describe a new method to calculate the diffusing capacity (DO2), oxygen consumption (VO2) and blood flow of the synovial membrane. The principle of the method is to perfuse the joint cavity with two saline solutions, one with high and one with low oxygen and nitrogen partial pressures and to measure the oxygen and nitrogen partial pressures in the perfusate flowing out of the joint. Using a model of gas exchange between the joint and the membrane a set of equations was derived expressing the relationship between the blood flow, diffusing capacity and oxygen consumption and the oxygen and nitrogen flowing to and from the joint in the two different perfusion situations. In 12 rabbit knee joints we found a blood flow of 0.388 ml/min (SEM 0.027), VO2 of 0.495 microliters/min (SEM 0.196) and DO2 of 0.024 microliter/min/Torr SEM 0.003 (mean).
In osteoarthritis the changes of the synovial membrane may seriously alter the oxygen transfer characteristics from the capillaries of the membrane to the synovial fluid and hence impede or deprive the joint cartilage of its sole source of oxygen. In the present study we have estimated the blood flow (Q), diffusing capacity (DO2) and oxygen consumption (VO2) of the synovial membrane in the chronic non effusive stage of experimental osteoarthritis. In 14 osteoarthritic knee joints we found a statistically significant increase in oxygen consumption, compared to previously reported results from normal joints, whereas the diffusing capacity and the blood flow were unchanged. The implication of this is that the partial pressure difference required to overcome the increased oxygen consumption was increased with a factor 4.3 and that the oxygenation of the joint cartilage was reduced with approx. 30 Torr.
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Measurement of PO2, PCO2, and blood flow in skeletal muscle could be a supplement to examination in clinical practice. Mass spectrometry was utilized to measure these parameters in the resting anterior tibial muscle of healthy adults. The partial pressures of oxygen and carbon dioxide were 21 +/- 3.6 and 46 +/- 2.5 Torr, respectively. The intracompartmental pressure was 8 +/- 1.1 Torr. The oxygen tension in muscle varied only slightly when arterial partial pressure was increased. The blood flow (tissue perfusion coefficient) estimated by washout of an inert gas was 5.4 +/- 0.8 ml/100 g/min. The results are in accordance with those from animal studies of skeletal muscle. The study demonstrates the feasibility of measuring PO2, PCO2, and blood flow in skeletal muscle by mass spectrometry.
The pathogenesis of primary human osteoarthritis is unknown. It has been suggested that hypoxia caused by reduced subchondral blood flow plays a central role in the development of tissue damages in osteoarthritis. This hypothesis was investigated using an in situ technique based on mass spectrometry to measure subchondral pO2 and pCO2 in both femoral heads of patients with late stage unilateral osteoarthritis and the normal opposite hip. Intraosseous pressure was recorded and lactate concentrations and pH were measured in blood samples obtained from the two femoral heads. The subchondral pO2 in the diseased hip was significantly lower than pO2 in the normal hip (43 torr versus 63 torr). The intraosseous pressure was significantly higher in the diseased than in the normal hip. The lactate concentration showed a 50% increase in the diseased hip. There were no differences in pCO2 and pH between the two locations.
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The frequency of inflammatory bowel disease in the Faroe Islands was estimated retrospectively for the years 1964 to 1983. A pronounced increase in the incidence of ulcerative colitis from 2.1 to 12.8 per 100,000 was found. The mean incidence in the period was 7.5/100,000; the prevalence was 157.3/100,000 on 31 December 1983. The change in frequency of Crohn's disease was insignificant, and the incidence of the disease was low compared with in other countries (1.75/100,000); the prevalence was 31.8/100,000 on 31 December 1983. The increase in incidence rate of ulcerative colitis was distributed equally between the two sexes, and a pronounced increment was found among young women.