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Biomedical subjects

R A Meals

Publications and source records attributed to R A Meals.

At least 37 records · Page 2Linked to original sources
PubMed1994

The effect of experimental hemarthrosis on joint stiffness and synovial histology in a rabbit model.

The effect of a single injection of unpreserved blood on joint stiffness and on synovial and cartilage histomorphology in the ankle joints of rabbits was determined at ten and 28 days after injection. The same volume of saline was placed in the contralateral ankle for comparison. After ten days, the hemarthrosis ankle was stiffer than the control ankle (p < 0.027), whereas at 28 days there was no statistical difference in stiffness between the hemarthrosis and control ankles, regardless of whether the limbs had been immobilized. Also after ten days, the hemarthrosis ankles had varying amounts of clotted blood, darkened articular cartilage, hypertrophic synovium with reactive blood vessels, and macrophages containing heme. The gross and histologic appearance of the saline ankles was normal. After 28 days, there were no differences in gross or microscopic appearance between the two ankles of the caged or immobilized rabbits. All ankles exhibited retreating inflammatory response in the synovium and mild synovial thickening. Acute hemarthrosis, unassociated with fracture or discernible joint injury, caused only transient changes in joint stiffness and synovial histology. These results indicate that the presence of blood in an otherwise grossly uninjured joint should not lead to ultimate compromise in cartilage integrity or joint function. Therapeutic arthrocentesis for acute posttraumatic hemarthrosis does not appear to be necessary for the prevention of permanent problems.

Animals↗
PubMed1993

Effects of antihistamines on joint stiffness and bone healing after periarticular fracture.

In an effort to blunt the inflammatory response following injury, we studied the effects of antihistamines on joint stiffness and bone healing after periarticular fracture. The hind limbs of 37 New Zealand white rabbits were instrumented with intramedullary Steinmann pins to allow immobilization after creating a distal tibia fracture. After periarticular ankle fracture, the rabbits were divided into groups to receive chlorpheniramine, low-dose terfenadine, high-dose terfenadine, or no antihistamine. Antihistamine was administered for the first 5 days after fracture. At 3 weeks after fracture, the rabbits treated with antihistamines showed a significant reduction in joint stiffness compared to control animals. To determine if antihistamine also retarded bone healing, an additional 12 New Zealand white rabbits underwent bilateral drilling of the midshaft of the femur with a 2.5 mm Steinmann pin. Six animals received oral terfenadine, and six served as controls. After 5 weeks of cage activity, the animals treated with the antihistamine showed a significant decrease in energy to failure of the femurs on torsional testing. Qualitative microscopic examination revealed less mature callus at the site of the femoral cortical defect in those animals treated with the terfenadine. Antihistamine may have heretofore unconsidered benefits in preventing post-traumatic joint stiffness but may slow healing of associated bony injuries.

Animals↗
PubMed1993

Passive motion: the dose effects on joint stiffness, muscle mass, bone density, and regional swelling. A study in an experimental model following intra-articular injury.

We studied the effects of passive motion on joint stiffness, muscle mass, bone density, and regional swelling after an intra-articular injury. Instrumentation was applied to the hindlimbs of thirty adolescent New Zealand White rabbits to allow either passive motion or immobilization of the ankle. The knee was immobilized by the locking together of Steinmann pins that had been placed within the medullary canals of the tibia and femur. An intra-articular injury was produced by drilling of the tibial pin through the ankle joint into the talus and subsequent withdrawal of the pin from the ankle joint. The rabbits were divided into five groups, and they received four, eight, twelve, sixteen, or twenty-four hours of passive motion each day during the three-week period of study. One ankle of each rabbit was moved through an arc of 90 to 170 degrees of dorsiflexion at one cycle per minute, while the contralateral ankle was immobilized in 100 degrees of dorsiflexion with an aluminum splint, which was fixed to the aluminum block that was used to stabilize the knee joint. We found that sixteen and twenty-four hours of passive motion prevented stiffness of the joint. Passive motion for shorter periods was ineffective, even harmful, and resulted in stiffness ratios that were as much as four times higher than those of the control limbs (those treated with immobilization). Swelling of the limb decreased only in the group that received twenty-four hours of passive motion. Muscle mass increased by an average of 13 per cent (range, 4 to 34 per cent), in comparison with that of the immobilized limbs in every group that was treated with passive motion. Bone density was maintained only in the limbs in which the ankle became stiff (ankles that had been treated with passive motion for twelve hours or less). An inverse relationship was noted between the duration of passive motion and the radiographic density of the distal tibial metaphysis; this relationship was statistically significant (p < 0.01). The limbs treated for twelve, eight, or four hours each day showed progressively greater bone density in comparison with those treated with immobilization or with sixteen or twenty-four hours of passive motion.

Animals↗
PubMed1993

Posttraumatic limb swelling and joint stiffness are not causally related experimental observations in rabbits.

Periarticular and intraarticular fractures frequently cause limb swelling and joint stiffness. The two effects are widely assumed to be related--an assumption long held but never tested. Over a ten-year period, a rabbit hind limb model was developed and tested to ascertain methods of preventing or reducing limb swelling and joint stiffness after a local skeletal injury. Limb swelling was monitored for the three- to four-week duration of the studies by volume displacement, and joint stiffness was determined arthrographically. Mechanical treatment modalities tested included limb pressurization, passive motion of varying duration (from four to 24 hours daily), creation of an intraarticular hematoma, and creation of dependent edema. Chemical modalities tested included systemic and intraarticular steroids, intramuscular and oral nonsteroidal antiinflammatory drugs, topical dimethyl sulfoxide, two antihistamine drugs, and two diuretics. At statistically significant levels, all of the modalities tested affected swelling or stiffness, but only terfenadine, an antihistamine, affected both. Treatment with terfenadine resulted in decreased stiffness but increased swelling. When reviewing the results of all of the treatment modalities in concert, it is apparent that, in this model, limb swelling and joint stiffness after injury are not causally related. The significance of this work in forthcoming clinical trials for treatment of posttraumatic joint stiffness are noteworthy.

Animals↗
PubMed1992

Manual demands and consequences of rock climbing.

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.

Adolescent↗
PubMed1992

Intra-articular corticosteroid reduces joint stiffness after an experimental periarticular fracture.

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.

Animals↗
PubMed1992

Biomechanical effects of a new point configuration and a modified cross-sectional configuration in Kirschner-wire fixation.

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.

Animals↗
PubMed1992

Biomechanical comparisons of unidirectional and bidirectional Kirschner-wire insertion.

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.

Animals↗
PubMed1992

Cubital tunnel syndrome.

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.

Diagnosis, Differential↗
PubMed1991

Continuous passive motion versus immobilization. The effect on posttraumatic joint stiffness.

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.

Animals↗
PubMed1990

Pathologic fracture of the proximal ulna through a bone graft donor site.

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.

Aged↗
PubMed1989

Giant cell tumor of metacarpal treated by cryosurgery.

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.

Adult↗
PubMed1989

The effects of dexamethasone on periarticular swelling and joint stiffness following fracture in a rabbit hindlimb model.

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.

Animals↗
PubMed1989

Effects of short-term immobilization versus continuous passive motion on the biomechanical and biochemical properties of the rabbit tendon.

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.

Animals↗