Biomedical subjects
Publications and source records attributed to R A Meals.
A case of digital pacinian corpuscle neuroma leading to erosive changes in the adjacent proximal phalanx is reported. Characteristics and previous reports of this relatively uncommon hand tumor are discussed.
Types of rock climbing, hand-grip techniques, and training practices used by rock climbers are described. A survey was completed by 46 climbers. Three fourths of the climbers reported a climbing-related injury; of these injured climbers, almost one half reported a hand or wrist injury. More than half of the injured climbers had been treated by a physician for their injury. More than half of all climbers reported distal interphalangeal or proximal interphalangeal joint pain while climbing. Case reports of three climbers with acute hand injuries are presented to illustrate the minimal effects of their residual deficits on their climbing abilities. A wider understanding of the manual aspects of rock climbing and an awareness of the patterns and incidence of injuries in this sport will facilitate prevention, treatment, and rehabilitation.
Early care after surgery or trauma to the extremities often includes a period of immobilization. The resultant joint stiffness may require extensive rehabilitation and may permanently limit function of the limb. Posttraumatic joint stiffness is particularly vexing in the small joints. In an experimental model, we tested the effects of intra-articular corticosteroid injections on stiffness in a joint at risk of posttraumatic joint stiffness. Triamcinolone was injected into ankle joints of rabbits after distal tibial fractures. Three weeks after injury, joint stiffness increased 34% in ankles injected with the steroid. Stiffness in ankles injected with saline solution and in ankles treated with no injection increased 133% and 224%, respectively. Limb swelling and tibial torsional strength to failure were not significantly affected by either of the treatments.
Kirschner-type wires (K-wires) comprising three different point configurations and two cross-sectional shaft configurations were drilled into bone to determine the insertional force required and the holding power achieved with each type. Round K-wires with either a diamond point or a high rake-angle trocar point were compared with each other and with C-wires, which have a rounded square cross section and a short diamond point. The K-wires performed superiorly to C-wires with respect to bone penetration. The K-wires demonstrated about twice as much holding power as the C-wires. No significant differences in performance were detected between the diamond-tipped and trocar-tipped K-wires with respect to either insertion or pull-out. For all three wire-tip combinations, insertion was facilitated by faster drill speed, but holding strength was superior with slower speed. For ease of insertion, even at oblique angles, and for maximum holding strength, the high-rake angle, trocar-tipped K wire is best.
Peak axial loads on entry and peak pull-out loads were measured for Kirschner-wires (K-wire) inserted into canine metacarpals. The wires were placed using a standard, unidirectional drill and using an oscillating, bidirectional drill that reversed spin direction every 120 degrees. Seven trocar-tip wires were compared with seven diamond-tip wires using each drilling method. The trocar-tip wires demonstrated equal peak axial loads on entry when drilled at comparable speeds unidirectionally and bidirectionally. Pull-out load of the trocar tip after bidirectional insertion was less than that for unidirectional insertion but was still in the clinically useful range. The diamond-tip wire exhibited higher peak axial load on entry and lower peak pull-out load when drilled bidirectionally. Bidirectional insertion of a trocar-tip K-wire offers fixation characteristics comparable with those with unidirectional insertion and will potentially reduce the risk of soft-tissue damage associated with winding-up and avulsion of vital structures on the spinning shaft of a unidirectional driver.
Cubital tunnel syndrome is the second most common compressive neuropathy of the upper extremity. Key factors in the history, physical, and differential are outlined to assist the clinician in making an accurate diagnosis. Nonoperative measures and surgical options are reviewed, with medial epicondylectomy being the authors' preferred operative technique.
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Management of intraarticular fractures is often complicated by joint stiffness long after bony healing has occurred. The following experiments provide biomechanical evidence for the effectiveness of CPM in maintaining joint function in stabilized articular injuries. The ankles of ten adolescent New Zealand white rabbits were penetrated by Steinmann pins to create an intraarticular injury. One limb of each animal was immobilized, and the contralateral limb was placed in a continuous passive motion (CPM) machine for three weeks. Joint stiffness of each ankle was quantified with an arthrograph before injury and after three weeks of treatment. Hindlimb volumes were recorded before injury and monitored at weekly intervals using a water-displacement method. Joint stiffness increased 2.6 times the preinjury levels in limbs that were immobilized for three weeks. There was no statistically significant increase in joint stiffness in ankles treated with CPM compared to preinjury values. The posttraumatic difference between the CPM-treated and immobilized limbs was highly significant; limb swelling was not affected by CPM.
Complications of harvesting autologous bone graft from the iliac crest and tibia are well known; exclusive use of upper extremity donor sites in hand surgery has therefore been advocated. Six weeks of postoperative elbow splinting has been recommended after harvest of large proximal ulnar grafts. We report two cases of pathologic fracture of the proximal ulna complicating local bone grafting and question whether the risk of fracture and the attendant patient inconvenience and potential joint stiffness incurred by postoperative immobilization are exceeded by the morbidity of carefully done iliac crest grafting.
We report the case of a 44-year-old woman with a giant cell tumor of the fourth metacarpal head of her dominant left hand that was treated with cryoprobe freezing, curettage and bone grafting. Three years after operation the metacarpophalangeal joint remained normal both functionally and radiologically. The tumor has not recurred. Cryoprobe killing of giant cell tumors of the hand can offer effective direct tumor eradication, as well as maintaining normal bone architecture and preserving full function.
An established rabbit hindlimb model was used to determine the effects of systemic steroid administration on posttraumatic limb swelling and joint stiffness. Dexamethasone acetate was administered intramuscularly to the test rabbits in one of four doses two hours following fracture as well as one and two weeks later. Dexamethasone did not produce a significant decrease in swelling but did produce a statistically significant dose-dependent decrease in ankle stiffness compared to controls. Tibia torsional strength to failure was not adversely affected.
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Little work has been done on the effect that continuous passive motion (CPM) may have on maintaining the mechanical and biochemical characteristics of tendons deprived of normal load-bearing stimuli. This study compared changes in mechanical properties and collagen concentrations of the tibialis anterior tendon between two groups of rabbits: control animals that received no treatment and experimental animals that received CPM to one ankle and immobilization to the other. Treatment duration was three weeks. Mechanical testing yielded values for elastic modulus, stiffness, stress, strain, and strain energy density at linear and maximum loads. Hydroxyproline concentrations were measured to determine tendon collagen content. Findings indicated that cyclic tensile loading of tendons by CPM lessened the harmful effects of immobilization. Linear load and stress for CPM and control tendons were similar, while the same measures for immobilized tendons were 16% and 25% less than control tendons. Ultimate strength of the control tendons, however, exceeded CPM tendons by 16% and immobilized tendons by 20%. Hydroxyproline levels were comparable for the CPM, control, and immobilized tissues. For a short duration (three weeks), CPM reduced the detrimental effects of immobilization in the tendon, primarily in the linear-load region.
Using a rabbit distal tibia fracture model treated by immobilization for three weeks, the effects of two nonsteroidal antiinflammatory drugs on postfracture limb swelling, joint stiffness, and torsional bone strength were examined. Limb swelling in rabbits treated with low-dose piroxicam was reduced by 39%, and high-dose piroxicam reduced limb swelling by 86%. Flunixin, tested at one dose, reduced swelling by 53%. Neither piroxicam nor flunixin affected ankle stiffness or tibia torsional strength.
Multiple efforts had failed to heal an infected nonunion of the proximal ulna. A flexor carpi ulnaris muscle pedicle flap was used to improve blood supply and soft-tissue coverage at the nonunion site. The muscle flap and application of the principles of nonunion treatment promoted bone healing and restoration of useful elbow function.
Sign language is the fourth most commonly used language in the United States. Despite the frequent need for this unique upper limb function, little is known regarding the demands and consequences of signing. This article (1) reviews 15 signers with upper limb abnormalities to determine how the abnormalities affect their signing, and (2) explores overuse syndromes in six sign language interpreters. Because of the way the sign language is constructed, only the most severe, bilateral limb abnormalities affect signing, and no extraordinary measures beyond standard, high quality hand care is required to improve function. To treat overuse syndromes in sign language interpreters, customary conservative treatments have generally been useful, but prevention is greatly preferable to treatment.
Over the past 20 years the available methods for thumb reconstruction following major loss have changed dramatically, primarily through the continued development of microsurgical techniques. Replantation effort is generally indicated when the injury is favorable and the patient can safely undergo emergency and possibly prolonged surgery. Since secondary reconstructions vary markedly with respect to anticipated function and appearance, donor site requirements, and other important factors, the reconstruction method should be individualized according to the patient's age and general health, functional demands, and cosmetic expectations.
Dimethyl sulfoxide (DMSO) is an inorganic compound with many interesting in vitro properties, including the ability to scavenge oxygen-free radicals. DMSO has been used to treat a variety of clinical conditions, especially musculoskeletal trauma, but valid data regarding its effectiveness are lacking. This paper reviews the pharmacology of DMSO and reports on its effectiveness in reducing posttraumatic limb swelling and ankle joint stiffness in a rabbit hind limb model. The left and right hind limbs of the test and control animals were instrumented and fractured identically. DMSO was applied daily to the skin of only one limb in the test animals. DMSO reduced postinjury ankle stiffness in both ankles of the test rabbits by 41% but had no effect on limb swelling compared to control rabbits. Postulated mechanisms of decreased joint stiffness include oxygen-free radical scavenging and inhibition of fibroblast proliferation.