James A. Albright

Anatomic variations of the blood supply of the soleus muscle

A total of 36 cadaver and fresh amputation specimens were studied by dissection. Two vascular patterns were identified--a segmental posterior tibial artery (Type 1) and a proximally dominant posterior tibial artery (Type 2). Type 1 was seen in 77.8% of cases, and Type 2 in 22.2%. Injection studies in five fresh specimens demonstrated numerous cross-connections between the two halves of the muscle. A distally based hemisoleus flap should not be performed when a Type 2 vascular pattern is encountered. Also, vascular cross-connections between the two halves of the soleus muscle should be preserved, when possible.

Electric Silver Antisepsis

Use of silver as a topical antimicrobial agent has been hampered by the absence of a method of providing sustained delivery of the silver ions. One possible solution is the use of silver-coated fabrics as both wound dressings and silver-ion emitting anodes in a simple electric circuit. The antimicrobial dose would then be determined by Faradays law. In the biological environment, silver-coated materials studied thus far have not behaved as predicted. We have discovered a silver-coated fabric, designated IT, that is almost perfectly Faradaic in vitro up to 0.8 C. The silver ions thus liberated were effective in inhibiting the growth of microorganisms. IT has potential for development as a charge-controlled topical antimicrobial agent.

Ischemic injury of the hand from intra-arterial propylhexedrine injection

A number of adverse consequences can result in the upper limb from parenteral drug abuse. Propylhexedrine, a drug similar to amphetamine, is easily obtained and causes severe injury to the limb when injected intra-arterially. This report describes an inadvertent case of intra-arterial propylhexedrine injection into the radial artery, the natural course of which resulted in digital amputations. The cause and diagnosis of this injury is discussed, and a protocol for treatment is presented.

Orthopaedic Applications of Carbon Fibers

Andrew A. Marino, Stephen Fronczak, atmosphere. Graphite fibers are purer and more crystalline Clarence Boudreaux, Douglas N. Liles, than carbon fibers, but they are also stiffer and not in general E. Michael Keating, and James A. Albright clinical use. Department of Orthopaedic Surgery BIOLOGICAL RESPONSE Louisiana State University Medical Center How does the body react to carbon fibers? We implanted School of Medicine in Shreveport bundles of 5000 8-micron carbon fibers in muscle, fat, and

Treatment of tendon injuries in thoroughbred racehorses using carbon-fiber implants

Summary In two separate studies, implanted carbon fibers were used to treat tendinitis of the digital flexor tendon in Thoroughbred racehorses. In the first study, in 28 horses that were salvage cases, 57% (P

Analysis of quantitative computed tomography scans using a Sun workstation

CT scans were taken of processed and unprocessed bone grafts. The CT images were transferred from magnetic tape to the hard disk of a Sun Microsystems SPARCstation 2 GX. Each CT image was stored in a separate image file. The bone sample images were then analyzed using image processing software to obtain a measurement of bone mineral density for each sample.<<ETX>>

A method to characterize burst fractures

The estimation of the pre operation and post operation canal geometry and interpedicular distance of burst fracture clinical cases has not been well documented. In this study a quantitative method was developed to estimate these parameters from clinical CT images in a SUN 2GX SPARCstation using the SUN VISION Software. In an initial cadaveric study the methods to estimate these parameters were set and it was found that the bone mineral density (BMD) correlated with the fracture load, degree of canal encroachment and changes in the interpedicular distance (IPD). For the nine burst fracture patients, the BMD correlated with the degree of canal encroachment but not IPD changes. After several months, the hardware was removed in three patients. The canal area increased and the IPD decreased in the affected vertebral body, showing significant recovery in each case.

Fixation of osteochondral fractures with absorbable pins

Smaller osteschondral fragments containing little or no cortex present difficult treatment dilemma. Metallic screws or Kirschner wires often require subsequent removal either as part of the original operative plan or because of problems such as loosening and/or cartilage erosion. An attractive alternative would be a biodegradable implant that would transfix an osteochondral fragment with minimal violation of the articular surface. The objectives of this study are (1) to compare osteochondral fracture fixation of 2mm polyglycolic acid (PGA) absorbable pins (Acufex, Manfield, Mass) with that of Kirschner wires (K-wires) in cadavers, (2) to review patient data where osteochondral fractures were fixed with PGA-pins. The following conclusions were obtained: (1) Cadaver Studies: The biomechanical parameters of the osteochondral fractures fixed with absorbable PGA pins were not statistically different from those fixed with K-wires. Based on these laboratory studies it appears that fixation of osteochondral fractures with bioabsorbable PGA pins may offer a viable alternative to the use of K-wires. (2) Clinical Cases: A short follow up period with four clinical cases indicated that in carefully selected injuries, fixation with absorbable pins could become the treatment of choice of smaller joints. For severely comminuted fractures about major joints, PGA absorbable pins may be an adjunct to metal fixation.

A biomechanical study of 150/spl deg/ vs. 135/spl deg/ hip screws in femoral neck fractures

Femoral neck fractures have been difficult to treat with nonunion and avascular necrosis reported in 10% to 40% of cases. The hypothesis tested here was to determine whether a femoral neck fracture fixed with a 150/spl deg/ screw is more stable than that fixed with a 135/spl deg/ screw. The objectives were to measure axial stiffness, torsional stiffness, and failure strength of femoral neck fractures (Pauwels III). Also, CT derived bone mineral density (BMD in units of K/sub 2/KPO/sub 4/ mg/cc equivalent) was measured. The following results were obtained: 1) The 150/spl deg/ hip screw demonstrated greater axial stiffness, as well as a preferred mode of failure (impaction at the fracture site). This is less likely to lead to nonunion or avascular necrosis than is the shearing action at the fracture site with the 135/spl deg/ hip screw. 2) The 135/spl deg/ hip screw demonstrated greater resistance to rotation. 3) CT derived BMD did not correlate with either axial or torsional stiffness of intact or fixed bones.

Quantitative computer assisted tomography (QCT) and mechanical properties of cancellous bone

The density of cylindrical cancellous bone samples was obtained by quantitative computer assisted tomography (QCT). Their compressive strength was measured. Two groups of purified bone graft cylinders (Pelican Tissue Bank) were tested. In one, the major trabecular orientation was vertical, while the other had random orientation. In addition, cancellous bone plugs were harvested from the femoral head, trochanter and condyles of both femurs of a fresh 40 year old cadaver keeping the samples orientation in the direction of physiological loading. The correlation between strength and bone mineral density by QCT showed a power law relationship for the processed bone graft samples with preferred trabecular orientation and unprocessed cadaver bone plugs. No correlation was seen for the group with random trabecular orientation. Thus trabecular orientation plays an important role in relating the strength to mineral density values by QCT.<<ETX>>