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Biomedical subjects

W G Mackenzie

Publications and source records attributed to W G Mackenzie.

13 recordsLinked to original sources
PubMed1999

Injury to the growth plate after Pemberton osteotomy.

The Pemberton osteotomy involves cutting directly into the iliopubic and ilioischial limbs of the triradiate cartilage of the acetabulum. Complete closure of the triradiate cartilage after this osteotomy has been described in case reports. The present experimental study was performed to determine whether physeal osseous bars formed after Pemberton osteotomy. Eight Pemberton osteotomies were performed in six piglets. The animals were killed, and the acetabula were studied with use of radiography, computed tomography, and histological analysis for evidence of physeal injury. Plain anteroposterior radiographs of the pelvis did not clearly demonstrate the formation of osseous bars. However, Bucholz radiographs, made with the acetabulum placed directly on the cassette, showed osseous bars in three of the four specimens that were studied in this manner. Histological sections of the eight specimens of triradiate cartilage demonstrated five osseous bars in the iliopubic limb and four in the ilioischial limb. In two specimens, there was disruption of the cartilage without osseous bridging. Only two of the eight specimens had normal histological findings in both the iliopubic and the ilioischial limb of the triradiate cartilage.

Animals↗
PubMed1996

Extending the spectrum of distal arthrogryposis.

We describe a mother and son with multiple, non-progressive, congenital contractures, camptodactyly and absent flexion creases, expressionless face, blepharophimosis, microstomia, and short stature. Although these cases share similarities with the autosomal-recessive Schwartz-Jampel and Marden-Walker syndromes, they have a different mode of inheritance and lack myotonia, one of the most characteristic findings of the Schwartz-Jampel syndrome. Our cases most closely resemble those previously reported as distal arthrogryposis type IIb, although in our patients the proximal joints are severely affected and extraocular involvement is absent. Hearing loss is present in one and cleft palate in the other of our patients; these findings were previously described in arthrogryposis syndromes other than type IIb. We suggest extending the spectrum of distal arthrogryposis to include these manifestations, since there appears to be significantly overlap between the different syndromes.

Abnormalities, Multiple↗
PubMed1994

Femoral forces during limb lengthening in children.

A system was designed to measure forces during femoral lengthening using force transducers on an Ilizarov femoral frame. Measurements were made in three teenaged subjects overnight and during weight bearing. A progressive increase in axial load secondary to distraction was seen, forces peaking at 428, 447, and 673 N for the three subjects. Little change in force transmitted by the frame was observed during weight bearing. Measurements taken before and after each individual lengthening showed no change in axial force or bending moment (p > 0.01). A diurnal variation of axial load was found (p < 0.01). Forces at midnight were greater than in the morning in all the subjects, with a mean difference of 113 N (p < 0.01). Distraction forces measured in the femur during distraction are greater than those previously measured in the tibia. Evidence exists that the callus is stiff and may be the origin of these forces.

Adolescent↗
PubMed1988

Eosinophilic granuloma of bone.

This is a review of 48 patients registered in the University of British Columbia Bone Tumour Registry as having eosinophilic granuloma, with emphasis on the historical development, treatment and results. Comments on the place of scintigraphic imaging are included. Eosinophilic granuloma in its solitary form is a self-limiting disease requiring no treatment. It can, however, progress to multifocal disease or the historically important triad known as Hand-Schüller-Christian syndrome. There is some evidence that it may have an immunologic basis, but the authors have little new to offer with respect to its etiology.

Adolescent↗
PubMed1985

The vascular and nerve supply of the human meniscus.

Twenty-three fresh, cadaver knees were studied to evaluate details of the vascular and nerve supply of the menisci in humans. Vascularity was investigated using dye and latex injections, and the nerve supply was studied microscopically using a variety of special stains. Vessels arise mainly from medial and lateral inferior and middle geniculate arteries. Radial branches from a perimeniscal plexus enter the meniscus at intervals, with a richer supply to the anterior and posterior horns. Vessels supplying the body are limited to the peripheral one-third, except in the fetus. There is an avascular area adjacent to the popliteus tendon. The perimeniscal tissue is richly innervated. Most nerves are associated with vessels. Smaller nerves and axons run radially in convoluted patterns. Single axons course through the perimeniscal tissue, and many nerves are seen in the interstitial tissue of the outer one-third of the meniscus and in the anterior and posterior horns. The inner two-thirds has no nerve fibers.

Aged↗
PubMedDate not supplied

Hip arthroscopy in Legg-Calve-Perthes disease.

The case of a 7-year-old boy with Legg-Calve-Perthes disease is presented. He had a prominent island of superficial epiphyseal ossification in his right femoral head, an unusual finding in Legg-Calve-Perthes disease. Hip arthroscopy was used successfully to identify and treat the lesion. After the procedure, the patient had a reduction in pain and an increase in range of hip motion. We believe that this case demonstrates the effective use of hip arthroscopy in the treatment of this unusual sequela of Legg-Calve-Perthes disease.

Arthrography↗
PubMedDate not supplied

Acetabular volume.

Reconstructive acetabular osteotomies can affect the acetabular volume. Volume mismatch between the femoral head and the acetabulum should be an important consideration but is rarely evaluated before hip reconstruction. Accurate measurement of the volume of the acetabulum is difficult because of the unusual shape and spatial orientation of the acetabulum. In this study, we used three techniques (physical, two-dimensional computed tomography, and three-dimensional computed tomography reconstruction) to determine the volume of 18 pig, four sheep, and 15 model acetabulae. A comparison of pre- and post-Pemberton osteotomy volumes of three dysplastic acetabulae models and two patients with developmental dysplasia of the hip also was performed. The results indicate that accurate, reproducible volume determinations can be made by using all three techniques, and that certain data-selection modes can reduce the patient's exposure to radiation. In addition, we observed an increase in the volume of the acetabulum after the Pemberton osteotomy.

Acetabulum↗
PubMedDate not supplied

Avascular necrosis of the hip in multiple epiphyseal dysplasia.

We observed radiographic changes of avascular necrosis (AVN) of the capital femoral epiphysis in 9 hips of 11 patients with multiple epiphyseal dysplasia (MED). Plain roentgenography, bone scintigraphy, and magnetic resonance imaging (MRI) studies all revealed characteristic asymmetric changes in the presence of AVN superimposed on dysplastic femoral heads.

Child↗
PubMedDate not supplied

Accurate prediction of outcome after pediatric forearm fracture.

Factors affecting outcome after pediatric forearm fracture include fracture angulation and fracture position. A new index, axis deviation, combines these factors. Two review studies were performed to determine if axis deviation correlated with outcome. In the first study, 35 subjects were reviewed 2.7 years after fracture without radiographs. In the second study, 152 fractures were reviewed a mean of 4 years after fracture, with 124 patients consenting to undergo radiographs. In both studies, the new index, axis deviation, correlated better with restricted forearm movement than either degree of angulation or fracture position. Midshaft and distal remodeling occurred and could be predicted in terms of axis deviation. We propose that an axis deviation of < 5 at the time of union be the reduction criteria of pediatric forearm-shaft fracture regardless of fracture position.

Bone Remodeling↗
PubMedDate not supplied

Management of pulseless pink hand in pediatric supracondylar fractures of humerus.

Thirteen (3.2%) of 410 patients seen in British Columbia's Children's Hospital in Vancouver from January 1984 to September 1992 with supracondylar fractures did so with an absence of a radial pulse in an otherwise well perfused hand. A combination of segmental pressure monitoring, color-flow duplex scanning, and magnetic resonance angiography (MRA) appears to be a valid, noninvasive, and safe technique in evaluating patency of the brachial artery and collateral circulation across the elbow. Based on this study, early revascularization of a pulseless otherwise well-perfused hand in children with type 3 supracondylar fractures, although technically feasible and safe, has a high rate of asymptomatic reocclusion and residual stenoses of the brachial artery. Therefore a period of close observation with frequent neurovascular checks should be completed before more invasive correction of this problem is contemplated.

Adolescent↗
PubMedDate not supplied

Factors affecting fracture position at cast removal after pediatric forearm fracture.

The outcome of a pediatric forearm fracture is related to the angulation of that fracture at the time of union. We discuss the factors affecting the position of the fracture at union. Three hundred forty-six children with 369 reductions of forearm fractures were reviewed retrospectively. Quality of reduction at the time of operation and loss of reduction during the period of cast immobilization were assessed using axis deviation. Loss of reduction had a greater influence on the final position of the fracture at union than did the position of the fracture at initial reduction. To ensure a satisfactory outcome, all pediatric forearm fractures should be monitored with radiologic review and remanipulation if their axis deviation is > 5 in younger patients or > 3 in patients with fractures close to or after growth-plate closure. Right forearm fractures in boys were identified as a subgroup at greater risk for redisplacement.

Analysis of Variance↗
PubMedDate not supplied

An independent assessment of two clubfoot-classification systems.

We conducted an independent assessment of two clubfoot-classification systems. In a blinded trial, two orthopaedists scored 55 feet by using the classification systems developed by Pirani et al. and by Dimeglio et al. Thirty-seven of the feet were also scored by a physical therapist. By using the 10-point classification described by Pirani, the two physician examiners tallied total scores that were within one point of one another 89% of the time. The mean difference between the scores assigned by the two examiners was 0.6 points. For the 20-point classification described by Dimeglio et al., total scores tallied by the two physician examiners were within two points of one another 91% of the time. The mean difference between the scores assigned by the two physician examiners was 1.4 points. Correlation coefficients were 0.90 (p = 0.0001) for the Pirani classification, and 0.83 (p = 0.0001) for the Dimeglio classification. Correlation coefficients were much lower for the first 15 feet scored and were also lower when the therapist's scores were included. Overall, both classification systems had very good interobserver reliability after the initial learning phase.

Clubfoot↗