Biomedical subjects

P M Witschger

Publications and source records attributed to P M Witschger.

3 recordsLinked to original sources

PubMed1994

[Instrumental muscle pressure measurement in acute and chronic compartment syndrome].

Acute compartment syndrome is a serious complication of trauma to the extremities. Increases in intra-compartmental tissue pressure result from increases in fluid pressure. The indication for a fasciotomy in impending compartment syndrome depends on the tissue pressure. To facilitate the diagnosis of high intramuscular pressure in acute and chronic compartment syndrome, we have developed a pressure monitor that enables us to measure pressure simply and exactly. The pressure monitor has a very low drift, high accuracy and linearity, and is easy to handle. The clinical application of the pressure monitor proved to be a useful tool in the management of an injured limb. This article reviews the pathophysiology and mechanism of acute and chronic compartment syndrome as well as the intracompartmental pressure monitoring.

Compartment Syndromes↗

PubMed1991

Biomechanical evaluation of a biodegradable composite as an adjunct to internal fixation of proximal femur fractures.

Internal fixation of comminuted unstable fractures of the severely osteoporotic proximal femur is sometimes supplemented with polymethyl-methacrylate (PMMA). We here report an in vitro biomechanical evaluation of a biodegradable particulate composite that might be used for similar purposes. The composite includes a matrix phase consisting of a hydrolyzable prepolymer [polypropylene fumarate (PPF)] cross-linked with methacrylate monomer, and a particulate phase consisting of tricalcium phosphate and calcium carbonate. We implanted dynamic hip screws in 22 cadaveric proximal femora and measured the yield load for an oblique force applied to the femoral head. The hip screws were then reinforced with either PMMA or the PPF composite and tested again. On the basis of analysis of variance, the average increases in yield load for PMMA and PPF reinforcement of 1,750 and 1,130 N were statistically significant (p less than 0.00005), suggesting that both materials enhance congruence between implant and bone and thereby increase the projected load-bearing area of the implant. The increase in yield force with PMMA was slightly higher than the increase with PPF (p less than 0.05), but both values after reinforcement were close (3,790 +/- 561 N for PMMA vs. 3,240 +/- 669 N for PPF). If we can demonstrate that appropriate rates of degradation, bony ingrowth, and static and fatigue properties can be achieved in vivo with this system, our data suggest that this PPF composite may have potential as an adjunct to the internal fixation of unstable fractures of the osteoporotic hip.

Aged↗

PubMed1989

[Girdlestone total prosthesis].

Thirteen out of 17 patients with a hip prosthesis according to the Girdlestone procedure were studied at a follow-up time of 26 months to 10 years. Seven patients were found to be satisfied with the total prosthesis, while the others complained about pain, walking disability and an insufficient range of motion. The implantation of a prosthesis using the Girdlestone procedure is technically difficult and should be restricted, as the results are superior to the Girdlestone hip in only a carefully selected group of patients with good abductor muscles and unsatisfactory results after the Girdlestone operation.

Femoral Neck Fractures↗