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Biomedical subjects

I Hvid

Publications and source records attributed to I Hvid.

At least 91 records · Page 5Linked to original sources
PubMed1985

Contribution of the cortex to epiphyseal strength. The upper tibia studied in cadavers.

Non-destructive measurements of compressive stiffness were carried out on 20 proximal tibial autopsy specimens. The tibial epiphyses were first loaded through a template covering all but the peripheral 2 mm of the subchondral resection surface, then through the whole resection surface, and finally, after removal of the peripheral shell. A slight increase of the stiffness coefficient resulted from peripheral contact. Stiffness increased significantly after removal of the shell, but several potential sources of systematic error in this part of the investigation raise questions as to the validity of this finding. The area-corrected stiffness showed a decrease as a result of peripheral contact; this result indicates that the peripheral rim of bone has a lower area-corrected stiffness than the central bone, a finding which is incompatible with the concept of a true cortical shell at the epiphyseal level.

Cadaver↗
PubMed1985

Trabecular bone strength profiles at the ankle joint.

The mechanical strength of trabecular bone at the ankle joint was studied in ten amputation specimens by means of multiple penetration tests. Tibial bone was considerably weaker than talar bone (40% on average). An area of peak bone strength located posteriorly and medially to the center of the joint was found in most joints. The variation of bone strength with the depth from the surface was studied by comparing five successive 2-mm levels. At the tibia there was a statistically significant decrease of bone strength from the first to the second level. At the talus, bone strength increased at first, then decreased significantly. The absolute values of strength recorded suggest that in a substantial number of the joints studied, the resection surfaces--especially at the tibial side--might be too weak to support the loads imposed by current prosthetic designs.

Ankle Joint↗
PubMed1984

Total condylar knee arthroplasty. Prosthetic component positioning and radiolucent lines.

Prosthetic positioning and overall postoperative alignment were studied in 138 consecutive total knee replacements, using the Insall/Burstein total condylar knee system. Overall alignment was within 7 +/- 5 degrees of valgus in 63 per cent of the knees, while tibial component positioning was within 4 degrees of tilt in any direction in 53 per cent of the knees. A radiolucency index incorporating width and extent of radiolucent zones at the tibia was shown to progress from 3 months to 2 years postoperatively. The radiolucency index 2 years postoperatively was higher with postoperative varus alignment in the rheumatoid arthritis group; a tibial component tilt of more than 4 degrees in any direction increased the radiolucency index in both treatment groups.

Adult↗
PubMed1983

Compressive strength of tibial cancellous bone. Instron and osteopenetrometer measurements in an autopsy material.

The topographic variation of proximal tibial cancellous bone strength was investigated in 12 knees from routine autopsies. Samples from eight knees were tested to compressive failure in an Instron material testing machine, and four knees were tested with the osteopenetrometer, an instrument developed for intraoperative measurement of bone strength. Ultimate stress, elastic modulus and energy absorption of the bone were calculated from the Instron-curves. Mechanical properties varied considerably from knee to knee, but the topographic patterns were remarkably constant. The medial condyle showed the highest strength, the intercondylar area the lowest. On the medial side the bone was strongest at the front, while on the lateral side the reverse was true. The two horizontal levels tested did not differ significantly. The osteopenetrometer measurements closely modelled the pattern of ultimate stress.

Adult↗
PubMed1982

The appendiceal mass: results of conservative management.

During a ten-year period 193 patients with an appendiceal mass--and subsequently proved postinflammatory changes of the appendix--were treated conservatively. The course was uneventful in 88%. Twelve per cent underwent delayed surgical intervention caused by complications with one death. Elective appendectomy was performed after three months with a complication rate of 3.4%. In comparison with series with early operation the conservative management seems to carry a lower morbidity. The value of elective appendectomy is discussed.

Abscess↗
PubMed1982

The quadriceps angle and its relation to femoral torsion.

In 29 patients with patellofemoral complaints paired values of Q-angle and internal hip rotation were determined. In addition the patellar height index of Insall & Salvati (1971) was calculated from measurements on lateral radiographs of the knees. Both Q-angle and internal hip rotation were significantly higher in women than in men and there was a statistically significant correlation between these two measurements. There was no significant correlation between Q-angles and patellar height indexes. As external hip rotation can generally be taken as a measure of internal femoral torsion, these findings favour the hypothesis of a torsional malalignment syndrome of the patellofemoral joint.

Adolescent↗
PubMed1981

Perichondrial autograft in traumatic chondromalacia patellae. Report of a case.

A case of clinically successful autografting of rib perichondrium to the patella in a 55-year-old woman suffering from painful traumatic chondromalacia patellae is reported. A postoperative arthrogram however did not show any significant regeneration of cartilage but arthroscopy revealed a smooth surface of cartilage on the patella. Biopsies were not performed.

Cartilage↗
PubMed1981

Chondromalacia patellae. The relation to abnormal patellofemoral joint mechanics.

Twenty-two patients treated non-operatively for chondromalacia patellae were followed up after an average of 5.7 years in order to evaluate the effect of abnormal patellofemoral biomechanics on the natural history of the symptoms. Clinical and radiological investigation revealed 15 patients with signs of malalignment, femoral trochlear dysplasia or excessive lateral pressure syndrome, 3 patients with marginal signs of malalignment and 4 patients with no demonstrable abnormalities. A statistically significant difference in the evolution of symptoms between the normal and the abnormal group is demonstrated, 14 out of 15 in the latter group having unchanged or worsened symptoms. The stage of chondromalacia change as judged arthrographically at the beginning of the observation period did not influence the clinical outcome.

Adolescent↗