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Biomedical subjects

H Kofoed

Publications and source records attributed to H Kofoed.

At least 19 recordsLinked to original sources

Avulsion fracture of the calcaneus: report of a case using a new tension band technique.

We report a case of avulsion fracture of the calcaneus in an 83-year-old woman. Nonoperative treatment was not considered satisfactory. However, the os calcis was osteoporotic, and internal fixation therefore was performed with a transverse Kirschner pin through the os calcis, securing a figure-of-8 metal tension band wiring to the fragment. We suggest that this technique provides a strong internal fixation in selected cases.

Aged

Cylindrical cemented ankle arthroplasty: a prospective series with long-term follow-up.

From 1981 to 1985 28 ankle arthroplasties were performed using a congruent and cylindrical ankle design. The talus component was an anatomically shaped cap to cover the talus dome and the facets. The tibial component was congruent toward the talus and had two parallel bars on the back for fixation into the distal tibia. The diagnosis was osteoarthritis in 15 cases and rheumatoid arthritis in 11 cases (two bilateral cases). There were seven failures, giving a cumulative estimated survival rate of 70% for the prosthesis at 12 years.

Adult

Fracture of the femoral neck: identification of the optimal screw position by migration ratio.

A consecutive series of fractures of the femoral neck treated with sliding screw and plate osteosynthesis were evaluated radiographically for the optimal position of the screw by use of migration indices. A naturally occurring optimal position of the screw was discovered. It was characterized by four positional indices in the head-neck region which were significantly correlated with minimal migration (or best stability). This optimal screw position gave a better prognostication of reduced risk of early fracture failure compared with the usual sectional division of the femoral head as indicator of screw position.

Aged

Passive ankle mobility. Clinical measurement compared with radiography.

We compared goniometric assessment of passive ankle movement with radiographic measurements in 100 normal ankles. Significant differences were recorded in both dorsiflexion and plantarflexion; clinical measurements overestimated the range of movement. For scientific documentation of tibiotalar mobility, radiographic measurements should be used.

Adult

Intramuscular lipoma of the lower limb. Long-term follow-up after local resection.

We report 12 patients with infiltrating muscular lipomas of the lower limbs all treated by wide resection. During follow-up averaging seven years, the tumour recurred in five patients. Our results and those reported by others suggest that, in order to avoid recurrence, this tumour, although benign, should be treated by total excision of the muscle or by compartmental resection. Hormonal imbalance was suspected in 9 of the patients but an oestrogen receptor analysis of the histological samples proved negative.

Adult

Transcutaneous reduction and external fixation of displaced fractures of the proximal humerus. A controlled clinical trial.

A consecutive series of 31 displaced fractures of the proximal humerus were randomly selected for treatment either by closed manipulation or by transcutaneous reduction and external fixation. Follow-up assessed the quality of reduction and healing as well as the functional outcome. The external fixation method gave better reduction, safer healing and superior function.

Adult

Strength of implanted carbon fibers. Studies of the lumbar spine in goats.

The L3-4 supraspinous and interspinous ligaments in 10 goats were replaced with carbon fibers stabilized with silk-suture seizing. The implants were removed after 3 weeks in 5 animals and after 3 months in the other 5. The maximum traction strength of nonimplanted slings was 157 +/- 9 kg (M +/- SD). After implantation, the strength was reduced to 136 +/- 17 kg, and after 3 months to 107 +/- 9 kg. However, the maximum strength of the spinous processes was 71 +/- 19 kg, which was less than the strength of 3-month implants. We concluded that the carbon fiber sling stabilized with silk sutures could be used for replacement of the interspinous ligament.

Animals

Long-term results of Marmor arthroplasty in varus osteoarthritic knees.

Twenty-one osteoarthritic knees with an average varus angulation of 13 degrees were followed up for 7-10 years after resurfacing with the Marmor compartmental knee arthroplasty. There were 14 unicompartmental and 7 bicompartmental replacements, a total of 28 implants. The knees were assessed clinically according to the Hospital for Special Surgery knee rating scale. At the latest follow-up, 19 of these cases were still excellent or good. None of the knees had been corrected by more than the tightness of the ligaments allowed, and a varus inclination of an average of 2 degrees remained after operation and at the latest follow-up. Radiolucency of more than 2 mm around the tibial component was found in 2 out of 28 of the cases, but this was not associated with pain or disability, nor was wire breakage, found in 6 out of 28, or positional changes of the tibial component, which were seen in five patients. It is concluded that the Marmor compartmental knee arthroplasty is still indicated in osteoarthritic varus knees.

Adult

External fixation of displaced fractures of the proximal humerus. Technique and preliminary results.

A new technique for the treatment of displaced fractures of the proximal humerus is described. Twelve fractures in 11 patients were managed by transcutaneous reduction using a Steinmann pin, and external fixation with a Hoffmann-type neutralising bar connected to two half-pins in the humeral head and three half-pins in the shaft. The pins were removed after four weeks. Two patients sustained redisplacement after a further injury, but in the others reduction was maintained. Two cases of pin-track infection resolved after antibiotics, but delayed union resulted. There were no neurovascular injuries and at follow-up of 6 to 12 months no refractures had been seen. The early functional results were excellent or satisfactory in nine cases.

Adult

Respiratory gas pressures in the spine. Measurements in goats.

Normal values of pO2, pCO2, pH, and intraosseous pressure were measured in situ in the lumbar spine of goats. In the lumbar bodies and discs no difference existed between values found cranially and caudally. pO2 was lower and pCO2 higher in the nucleus pulposus than in the adjacent lumbar bodies. This emphasizes the nutritional route to the disc via the vertebral end plate. Intraosseous pressures in the cranial and caudal levels of the lumbar spine did not differ, and the pressures were the same as otherwise found in cancellous bone. These are the first combined in situ measurements of several basic metabolic parameters in the normal spine using recordings with continuous mass spectrometry. They may constitute a basis for further investigation of metabolism in the structures of the spine.

Animals

Arterial hypoxia does not affect subchondral pressure and regional blood flow.

The influence of arterial hypoxia on bone marrow pressure, regional blood flow and oxygen and carbon dioxide tensions was investigated by simultaneous and continuous measurements in the femoral condyles of 8 rabbits. Arterial hypoxia was obtained by hypoventilation. The subchondral gas tensions and regional blood flow were measured by a previously described technique based on mass spectrometry. Arterial hypoxia caused a significant decrease in subchondral oxygen tension and an increase in subchondral carbon dioxide tension. There was no significant change in bone marrow pressure and regional blood flow.

Animals

Aggressive fibromatosis. Report of two cases with rare clinicopathological manifestations.

Two cases of aggressive fibromatosis are described, one with tricentric origin and with the first tumor originating in the hand, the other with malignant transformation into a myxoid fibrosarcoma, grade III. The primary treatment of aggressive fibromatosis should be wide excision, and the follow-up should be long, taking into account the possibility of multicentricity and the risk of malignant transformation.

Adolescent

Synovitis causes hypoxia and acidity in synovial fluid and subchondral bone.

The purpose of the present study was to evaluate the environmental changes in synovial fluid and subchondral bone during synovitis in rabbits in which the knee joint on one side was subjected to a procedure causing instability; a traumatic synovitis rapidly developed. Three weeks following the procedure, partial pressure of oxygen (PO2), partial pressure of carbon dioxide (PCO2) and hydrogen ion concentration (pH) were measured in vivo in the juxta-articular bone and in the synovial fluid of both the normal and the affected sides. Mass spectrometry was used for simultaneous registration of PO2 and PCO2, while a monocrystalline antimony pH electrode was used for simultaneous measurement of pH in vivo. Hypoxia, hypercapnia and relative acidity were found in synovial fluid and subchondral bone of knees with synovitis. The metabolic environment of synovial fluid and subchondral bone was considerably changed at the 3-week stage of experimental osteoarthritis and this was probably secondary to regional venous congestion.

Animals

Effect of simulated joint effusion on subchondral haemodynamics and metabolism.

The purpose of the present study was to investigate the effect of simulated joint effusion on pO2, pCO2, the regional blood flow and intraosseous bone marrow pressure in the subchondral bone of rabbit. Mass spectrometry was used for simultaneous and continuous registration of subchondral pO2 and pCO2, while the relative argon signal was used for qualitative estimation of regional bone blood flow. The bone marrow pressure was recorded continuously by pressure transducers. Isotonic sodium chloride infusion at a constant pressure of 75 mmHg into the knee joint cavity constituted the basis for joint effusion. An instant increase in the subchondral bone marrow pressure followed the joint effusion (P less than 0.001). This resulted in a significant (P less than 0.01) decrease in the qualitative bone blood flow, significant (P less than 0.01) hypoxia and significant (P less than 0.01) hypercapnia in the subchondral bone. Joint effusion always lasted 30 minutes. Following its release all changes were reversed to normal values within 15 minutes. Within the period of observation no nervous or humoral factors seem to be brought into action. It was concluded that regional venous stasis was responsible for all changes, and that joint effusion should not be left untreated for long periods.

Animals

Hemodynamics and metabolism in arthrosis. Studies in the rabbit knee.

Arthrosis was induced in the rabbit knee, making it unstable by ligament resection. Acidity and hypercapnia were found in the synovial fluid of the arthrotic knees, whereas oxygen partial pressure was normal. In arthrotic subchondral bone the intraosseous pressure and oxygen partial pressure were increased; intraosseous phlebography showed venous congestion. Histologic specimens showed increased subchondral bone formation, loss of cartilage and total depletion of glycosaminoglycans. The synovial membrane was hyperplastic and fibrosis was found in the underlying tissue. We suggest that changes in environmental haemodynamics and metabolism, although secondary in nature, may play an important role in the arthrotic process.

Animals