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Biomedical subjects

O O Oni

Publications and source records attributed to O O Oni.

At least 19 recordsLinked to original sources
PubMed1996

A comparison of isokinetics and muscle strength ratios following intra-articular and extra-articular reconstructions of the anterior cruciate ligament.

A prospective, randomized clinical trial was conducted to compare an intra-articular with an extra-articular reconstruction of the anterior cruciate ligament. Isokinetic muscle testing was carried out 6 months to 2 years following operation using the Biodex isokinetic dynamometer. The extra-articular procedure resulted in a lower deficit for the peak quadriceps and hamstring torques and the range of motion.

Adult↗
PubMed1995

A non-union model of the rabbit tibial diaphysis.

A consistently reproducible non-union model has been created in the adult rabbit tibial diaphysis. After making an osteotomy, the marrow was removed, the periosteum was excised and a silastic sheath was wrapped around the shaft. The fracture cleft was invaded by a non osteogenic fibrous tissue following the removal of the sheath after an interval of 4 weeks.

Animals↗
PubMed1995

Monitoring fracture healing with strain gauges: the effect on strain values of strain gauge location on the pin circumference.

In an attempt to establish some principles for the use of strain gauges in monitoring fracture healing, four strain gauges were fastened onto the most proximal pin of a Shearer external fixator applied to a hardwood fracture model. Compression and bending loads were applied and the strain data were obtained. The results show that the location of the strain gauge on the circumference of the pin has a significant effect on strain values.

Bone Nails↗
PubMed1995

Investigation of the torque-tension characteristics of a flanged external fixator pin.

The torque-tension characteristics of standard, conical and flanged external fixator pins and a cortical screw were compared using a commercially available testing apparatus. The flanged pin and the screw were similar in behaviour, and converted torque into tension more efficiently than conical and standard external fixator pins.

Biomechanical Phenomena↗
PubMed1995

Swan-neck deformity as a complication of the Agee technique.

Unstable dorsal fracture dislocations of the PIP joint of a finger commonly result in joint stiffness following immobilization or open reduction and internal fixation (Green and Rowland, 1984). The Agee dynamic external fixator, or force couple splint (Agee, 1978; 1987), was introduced in an attempt to avoid this complication and maintains a concentric reduction whilst allowing a full range of joint movement. The splint is constructed from three Kirschner wires and is activated by a single rubber band. A force couple is created across the proximal interphalangeal joint levering the base of the middle phalanx towards the palm whilst simultaneously lifting the distal end of the proximal phalanx dorsally to restore joint reduction. However, this technique is not without complications (Agee, 1987). We report a swan-neck deformity resulting from this treatment.

External Fixators↗
PubMed1995

An investigation of the bending stiffness of and the plane stresses generated by a flanged external fixator pin.

In an attempt to reduce pin loosening, a flanged external fixator pin has been designed and its bending stiffness has been compared with that of a standard pin. The pins were inserted into pilot holes previously drilled into a piece of teak hardwood. Loads of different magnitudes were applied at a fixed moment arm and force-deflection curves were obtained. Thereafter, percentage stiffness increase was calculated for each pilot hole size. The results show that the addition of a collar to the external fixator pin increases its stiffness and its ability to resist bending forces. In a parallel study, the stresses generated at the pin-bone interface by this pin and a standard pin were compared using finite element analysis techniques. The results show that the flange significantly reduced the stresses generated at the pin-bone interface. In addition, stresses were dissipated over a wider area.

Biomechanical Phenomena↗
PubMed1994

Localisation of bone-forming cells during fracture healing by osteocalcin immunocytochemistry: an experimental study of the rabbit tibia.

An immunocytochemical method was used to localise osteocalcin-producing cells during fracture healing in a rabbit model. In preliminary studies, tibial growth plates from young rabbits were used as a source of new bone formation, in order to determine the optimal tissue preparatory techniques. In the present study, a tibial shaft fracture was created in adult rabbits to study closed fracture healing. An indirect peroxidase method was used to stain paraffin-embedded tissue sections for osteocalcin. Osteocalcin-producing cells were positively identified at the periosteal and endosteal surfaces near the fracture site. Osteocalcin staining was not demonstrated in the surrounding soft tissues. At the interface between newly formed bone trabeculae and the cartilage layer within the callus, chondrocytic cells consistently showed localisation of osteocalcin. Within cartilaginous areas of the callus, some chondrocytes showed positive staining for osteocalcin. These cells were often seen in the proximity of blood vessels. The findings suggest that during fracture healing, under certain conditions, chondrocytes are capable of producing osteocalcin and thus could be considered capable of possible transformation into osteoblasts.

Animals↗
PubMed1994

The value of shoulder distension arthrography with intraarticular injection of steroid and local anaesthetic: a follow-up study.

A series of 51 patients, seen in Leicester, with "frozen shoulder", and referred for arthrographic examination, were assessed both before and after distension arthrography, using air and a low-osmolar contrast media combined with a steroid and local anaesthetic injection. 38 attended for further assessment at up to 6 months later. 16 patients were found to have a rotator cuff tear. There was no significant change in the mean range of active movement in the patients with rotator cuff tears, but symptomatic improvement ensued in 44% of cases. In those found to have no rotator cuff tear, and external rotation of less than 35 degrees, a significant improvement in range of movement was seen. While those with less limitation of external rotation showed no change in their range of movement, they did experience symptomatic improvement in 73% of cases. We conclude that shoulder distension arthrography, with steroid and local anaesthetic injection, may be of symptomatic benefit in patients with frozen shoulder and without a rotator cuff tear, while only those with external rotation of less than 35 degrees are likely to improve their range of motion.

Adult↗
PubMed1993

Vessel-like structures in the callus cartilage.

The recent claim that the callus cartilage contained vessel-like structures has been investigated by new immunocytochemical methods. The fracture callus was exposed to monoclonal antibodies which recognized damaged or regenerating endothelial cells. The proteolytic enzyme urokinase which is expressed by migrating endothelium was also studied. No vascular structures were identified by these methods which suggests that the callus cartilage is truly avascular.

Adult↗
PubMed1993

Pin-hole shear stresses generated by conical and standard external fixation pins.

Pin-hole shear stresses generated by tapered (conical) and untapered (standard) external fixator pins were compared using a photoelastic technique. The results show that shear stresses progressively increase as a conical pin is inserted but remain the same for the standard pin irrespective of the depth of insertion.

Bone Nails↗
PubMed1993

Bending stiffness of conical and standard external fixator pins.

The bending stiffnesses of a conical and a standard external fixator pin have been compared. The pins were inserted into pilot holes in a piece of teak hardwood and loads of different magnitudes were applied at a fixed moment arm. Force-deflection curves were obtained for each pin, and stiffness (newtons per metre) and percentage stiffness reduction were calculated for each pilot hole size. The results show that deflection increased (i.e. stiffness decreased) with increasing force or diameter of pilot hole. This loss of stiffness was linear for the standard pin but was bimodal for the conical pin.

Bone Nails↗