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Biomedical subjects

J H Wedge

Publications and source records attributed to J H Wedge.

35 records · Page 2Linked to original sources
PubMed1986

Biodegradable resurfacing of the hip in dogs.

Arthroplasties of the hips in dogs using a biodegradable poly-L-lactide cup to protect the regenerating cartilage following removal of normal articular cartilage and the drilling of multiple full thickness defects into subchondral bone were performed to determine whether or not the repair response could be improved. The poly-L-lactide cup degraded in approximately 60 days. The regenerating cartilage was much better in the experimental than the control dogs initially, but ultimately failed, perhaps due to inadequate duration of protection of the immature cartilage by the arthroplasty material.

Animals↗
PubMed1984

Clinical application of basic research on continuous passive motion for disorders and injuries of synovial joints: a preliminary report of a feasibility study.

Since 1970, when the concept of continuous passive motion (CPM) was originated by one of the authors (R.B.S.), he and a succession of his research fellows have investigated its biological effects on the healing and regeneration of articular tissues in a wide variety of experimental models in rabbits. From this basic research he concluded that CPM is well tolerated, seems to be painless, stimulates the healing and regeneration of articular tissues, prevents joint stiffness, and permits the normal healing of arthrotomy incisions. Beginning in 1975, one of the authors (H.W.H.), and in 1978, the remaining authors, (from two additional Canadian cities) applied the knowledge from the basic research on CPM to the orthopaedic care of human patients. The CPM devices for humans (CPM Mobilimbs), which have been designed in collaboration with University of Toronto engineers, include, to date, devices for the ankle-knee-hip, the elbow, and the finger. Indications for CPM in patients have been the immediate postoperative management following such operative procedures as open reduction and internal fixation of fractures, arthrotomy and arthrolysis for post-traumatic arthritis, synovectomy, surgical drainage for septic arthritis, release of extraarticular contractures, metaphyseal osteotomies, total joint replacement, and ligamentous reconstruction. The case reports of nine selected patients are presented as examples of the clinical application of CPM. These patients have been relatively free of pain, have maintained the increased motion gained at operation, and have accepted the application of CPM well. There have been no complications of CPM; the operative wounds have healed well and the period of hospitalization has not been prolonged. The authors believe that the clinical application of CPM is feasible and that the clinical and radiographic results of CPM in these patients are encouraging. Long-term, prospective clinical investigations (including control patients in whom CPM is not used) will be required to assess the efficacy of CPM in relation to the various stated indications.

Adolescent↗
PubMed1983

Ultrastructure of normal and torn menisci of the human knee joint.

Normal human menisci obtained at autopsy (seven cases) and the injured and uninjured portions of torn menisci obtained at surgery (nine cases) were studied with the electron microscope. The surface of menisci is composed of collagen fibrils surmounted by an electron-dense surface coat. Most of the cells in menisci are chondrocytes but a few fibroblasts and cells of an intermediate form difficult to classify as either fibroblasts or chondrocytes also occur. Mast cells are found at the vascularised periphery of the meniscus. Myofibroblasts were found in the injured portions of menisci in three out of the nine cases studied. A territorial matrix containing fibrils and proteoglycan particles with associated filaments is seen around or adjacent to chondrocytes, but sometimes this matrix is sparse or absent. The interterritorial or general matrix comprises collagen fibrils of widely varying diameters (25-180 nm) set in a sparse interfibrillary matrix containing proteoglycan particles. A few mature elastic fibres and several small or immature elastic fibres and collections of electron-dense filaments are seen in the general matrix. Also seen in this region are calcified bodies and matrical lipidic debris derived by the shedding of cell processes and in situ necrosis of cells. Other features seen in the matrix of the injured portion of the meniscus include: (1) membrane-bound cystic structures; (2) parting and fraying of collagen fibrils; and (3) pools of proteoglycan particles.

Adolescent↗
PubMed1982

Lumbar spinal nerve lateral entrapment.

In past years, lumbar nerve lateral entrapment seldom has been diagnosed. A presumptive preoperative diagnosis has been made based on clinical findings and radiographs demonstrating disc resorption. The Computed Tomography scan has made it possible to diagnose the lesion with certainty and accuracy. Treatment for patients who do not respond to conservative measures is a bilateral minimal partial laminectomy. The lateral canal is enlarged by removing the medial and anterior parts of the superior articular process. Adhesion formation is prevented by placing a free fat graft posterior to the dura. Instability is diagnosed by examining stress radiographs and, when present, is treated by a one level posterolateral fusion. After operation, marked improvement was obtained in 62% of patients and slight improvement in another 21%; 17% were unimproved. Sixty-two per cent of patients reported no pain or mild pain. Sixty-six per cent resumed their previous occupation.

Adult↗
PubMed1979

The natural history of congenital disease of the hip.

Fifty-four adults with eighty hips affected by congenital disease which had not been treated have been reviewed. Fifty-nine per cent of forty-two dislocated hips had fair or poor grading scores. The incidence of osteoarthritis was markedly increased in the presence of a well-developed false acetabulum. Unilateral dislocation led to valgus deformity and degenerative changes in the ipsilateral knee in seven of twenty-two patients. Dislocation did not increase the incidence of symptomatic lumbar spondylosis. The height of the dislocated head on the ilium was not found to be related to the prognosis for the hip, the knee or the lumbar spine and did not correlate with the development of the false acetabulum. Frank congenital subluxation eventually led to osteoarthritis of the hip.

Acetabulum↗
PubMed1978

Pathology and pathogenesis of lumbar spondylosis and stenosis.

Study of autopsy specimens of the lumbar spine makes it possible to construct a spectrum of pathologic change. Progressive degenerative changes in the posterior joints lead to marked destruction and instability. Similar changes in the disc result in herniation, internal disruption, and resorption. Combined changes in posterior joint and disc sometimes produce entrapment of a spinal nerve in the lateral recess, central stenosis at one level, or both of these conditions. Changes at one level often lead, over a period of years, to multilevel spondylosis and/or stenosis. Developmental stenosis is an enhancing factor in the presence of a small herniation or moderate degenerative stenosis. Lesions such as major trauma, spondylolisthesis, those following spinal fusion, Paget's disease, and fluorosis, on occasion act directly to produce central or lateral stenosis.

Aged↗
PubMed1976

Branched-chain amino acids, nitrogen excretion and injury in man.

1. Venous blood concentrations of the branched-chain amino acids, valine, leucine and isoleucine, and urinary nitrogen excretion have been measured in sixteen adult males, from 2 h to 7 days after injury, and in four adults after elective skin grafts. 2. In the injured group the concentrations of these amino acids rose significantly 24 h after injury and had doubled at 4 days and remained high; in contrast the skin-graft patients showed no significant change. 3. In those injured patients with initial hyperketonaemia, defined as more than 0-2 mmo1/1, the increase in concentrations of branched-chain amino acids at the fourth and seventh days after injury was significantly less than in those with normoketonaemia, and was accompanied by lower urinary nitrogen excretion throughout the whole period. 4. It is suggested that the changes in the concentration of branched-chain amino acids after injury indicate decreased uptake by muscle or excessive release due to an imbalance between protein synthesis and protein catabolism in this tissue.

Adolescent↗
PubMed1975

Initial effect of injury on ketone bodies and other blood metabolites.

The arterial and venous concentrations of ketone bodies and other metabolites were measured in twelve adults, from 2 to 24 hours after injury. Two groups could be distinguished, with or without hyperketonaemia (defined as more than 0.2 mmol per litre) in the 2-hour blood-sample. In the hyperdetonaemic group the concentrations of alanine, pyruvate, and lactate and the urinary nitrogen excretion were lower throughout the first 24 hours than in the non-hyperdetonaemic group. These preliminary results indicate that hyperketonaemia after trauma is associated with decreased protein breakdown.

Adolescent↗
PubMedDate not supplied

Unilateral posterior dislocation of the radial head in identical twins.

Congenital dislocation of the radial head, particularly bilateral, is seen in association with many syndromes affecting the musculoskeletal system. The consensus in the literature suggests that all isolated unilateral dislocations are posttraumatic in origin. Recent reports, therefore, recommend that unilateral dislocation be treated by open reduction, despite the benign natural history of the anomaly. We report on identical twins with isolated unilateral posterior dislocation in whom there is little doubt about the presence of the dislocation at birth.

Child↗
PubMedDate not supplied

Atypical manifestations of spinal infections.

Because of alarming delays in the diagnosis and treatment of vertebral osteomyelitis we have reviewed our experience over the past 15 years. Of the 36 cases, 25 were pyogenic and 11 tuberculous. Because of late referral there was a delay from onset of symptoms to diagnosis of at least three months in 13 patients. The reason for this was the failure of the initial physician to consider osteomyelitis in the differential diagnosis of a febrile illness associated with back pain. The majority of our patients from the onset did not have intense localized pain, tenderness and a high fever which is the classical clinical picture in this condition. Seven patients with a long history required surgical exploration and debridement of the lesion in order to eradicate the infection. The remainder did well on 6 to 12 weeks of antibiotic therapy. None required spinal fusion. Ten of 11 patients with spinal tuberculosis had curettage of the lesion and spinal fusion. Patients with diabetes, malignancy, alcoholism, corticosteroid therapy and recent lower urinary tract surgery were found to be at particular risk of developing spinal osteomyelitis. Very often it was difficult to identify differences in the presentation of pyogenic and tuberculous infections.

Adolescent↗
PubMedDate not supplied

The natural history of congenital dislocation of the hip: a critical review.

Studies of the natural history of congenital dislocation of the hip do not distinguish which particular features indicate a poor prognosis. In complete dislocation we have found that the development of a false acetabulum with thick sclerotic iliac bone more frequently leads to pain than those with little or no bony reaction of the ilium. Congenital dislocation leads to functional disability in all patients but only half have significant pain. Congenital subluxation and dysplasia of the hip are responsible for a high proportion of coxarthrosis. The lack of symptoms, and the subtle physical findings until irreversible degenerative changes occur, makes early diagnosis difficult. When recognized early, correction of the deranged anatomy must be done if coxarthrosis is to be prevented. Concentric hip motion and normal muscular function are essential for proper development of the joint. A reciprocal relation exists between the development of the proximal femur and the acetabulum. Structural abnormality of either eventually leads to joint dysfunction.

Hip Dislocation, Congenital↗