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Biomedical subjects

G D MacEwen

Publications and source records attributed to G D MacEwen.

At least 19 recordsLinked to original sources
PubMed1998

Fibrous dysplasia of the proximal part of the femur. Long-term results of curettage and bone-grafting and mechanical realignment.

We reviewed the long-term outcomes of treatment of fibrous dysplasia of the proximal part of the femur in twenty-two patients (twenty-seven femora). There were fifteen male patients and seven female patients. Patients who had monostotic disease had no involvement of the calcar femorale, fewer microfractures, less deformity, and stronger bone that could support internal fixation. Patients who had polyostotic disease had frequent involvement of the calcar femorale; more microfractures; severe deformity, including shepherd's crook deformity; and, in many instances, bone that could not support internal fixation. Twenty-two of the twenty-seven femora had a microfracture at the time of the initial presentation. At least one osteotomy was performed in four femora that had monostotic disease and in nine femora that had polyostotic disease. Curettage and cancellous or cortical bone-grafting did not appear to have any advantage compared with osteotomy alone in the treatment of symptomatic lesions, as all grafts resorbed with persistence of the lesion. At the time of the latest follow-up evaluation, no lesion had been eradicated or had decreased in size. A satisfactory clinical result was achieved in twenty patients (twenty-four femora): nine who had monostotic disease and eleven who had polyostotic disease. Two patients who had polyostotic disease and an endocrinopathy (one of whom had bilateral involvement) had an unsatisfactory result. All three femora in these two patients had a neck-shaft angle of less than 90 degrees at the time of the most recent follow-up evaluation. Varus deformity of the proximal part of the femur is best treated with valgus osteotomy and internal fixation early in the course of the disease. If the calcar of the femoral neck is involved or if the quality of the bone is such that internal fixation is not possible, a medial displacement valgus osteotomy can provide a more mechanically favorable position for healing of the microfracture.

Adolescent↗
PubMed1996

Charcot-Marie-Tooth disease associated with hip dysplasia: a case report.

A 31-year-old woman with a known history of hip dysplasia was found to have Charcot-Marie-Tooth disease following abnormal conduction studies done at the time of surgery. Physical examination in this patient was otherwise normal, and the diagnosis of Charcot-Marie-Tooth disease had not been previously considered. This report demonstrates the importance of keeping in mind the association between hip dysplasia and Charcot-Marie-Tooth disease.

Adult↗
PubMed1995

The effects of the interosseous membrane and partial fibulectomy on loading of the tibia: a biomechanical study.

The biomechanical basis for the treatment of delayed union of tibial fractures by partial fibulectomy has yet to be fully evaluated. To gain further insight into this problem, nine intact cadaveric lower extremities were instrumented with strain gauges on the surfaces of the tibia and fibula. The limbs were then subjected to axial loading with the ankle and subtalar joints placed in multiple positions. The specimens were loaded either through the distal femur or by direct loading of the tibial plateau. All specimens were first tested intact then after sectioning of the interosseous membrane and finally after partial fibulectomy. It was shown that during loading of the leg, the primary effects of the interosseous membrane were to stabilize the fibula and constrain its posterolateral bending. The fibular strains were not reduced to zero following sectioning of the interosseous membrane. Tibial strains measured on the anteromedial and anterolateral surfaces were consistently in relative tension, indicating a posterior bending force (anterior bowing) of the tibia. After partial fibulectomy, strains on these surfaces became relatively more compressive. With the ankle and subtalar joints in neutral position (0 degree flexion, 0 degree inversion/eversion) the strains on the anterior surface averaged approximately 10% more compressive relative to the intact condition. Tibial strains were observed to vary with the position of the ankle and subtalar joints. The fact that the anteromedial and anterolateral tibia surfaces were always in tension may explain why partial fibulectomy has not proved to be a uniformly successful treatment method for delayed union of the tibia. Furthermore, it points to the important role of "fracture personality" in the selection of treatment.

Aged↗
PubMed1994

Risk factors in Klippel-Feil syndrome.

STUDY DESIGN: This study kinematically evaluated radiographs of the cervical spine of patients with the Klippel-Feil syndrome in flexion and in extension to determine alterations from normal motion and potential risk. OBJECTIVES: The results in the study group were compared with those of a control group and with published standards for expected motion of the cervical spine. SUMMARY OF BACKGROUND DATA: The body of orthopedic and neurologic literature suggests a significant problem with neurologic deficit in patients with Klippel-Feil syndrome. No previous study has evaluated the kinematics of the cervical spine with a control group of normal individuals and published standards. METHOD: Lateral flexion-extension radiographs of the cervical spine of 111 patients with Klippel-Feil syndrome were kinematically evaluated to determine the motion of each open interspace and to compare motion with that of a control group and published standards. RESULTS: A statistically significant difference of increased motion per open interspaces in the upper cervical segment was noted in individuals with Klippel-Feil syndrome when compared with the control population. Conversely, total motion of the lower cervical segment was significantly decreased in the Klippel-Feil population when compared with normal controls. Lower segment motion per open interspace was not significantly different when the two groups were compared. CONCLUSION: The results of this study suggest that individuals with Klippel-Feil syndrome with hypermobility of the upper cervical segment are at risk for neurologic sequelae, whereas those with alteration in motion of the lower cervical segment are predisposed to degenerative disease.

Adolescent↗
PubMed1992

Stabilization of pediatric diaphyseal femur fractures with flexible intramedullary nails (a technique paper).

The indications for surgical stabilization of a pediatric diaphyseal femur fracture are expanding. Children with multiple system injuries, a head injury, and/or multiple fractures have fewer local and distant complications if the femur fracture is treated operatively. Other indications include a pathological fracture in osteoporotic bone, a fracture in a child with a preexisting condition that prevents the application of a spica cast, a child older than 10 years of age, or a child less than 10 years of age who cannot be kept adequately aligned using conventional (traction/casting) methods of fracture management. Here we describe a technique of stabilizing pediatric diaphyseal femur fractures using flexible intramedullary nails (Ender). This technique can be used in children of all ages and with all patterns of diaphyseal fractures.

Bone Nails↗
PubMed1992

Transpedicular convex anterior hemiepiphysiodesis and posterior arthrodesis for progressive congenital scoliosis.

Nine children with progressive congenital scoliosis underwent bilateral posterior spinal fusion supplemented with transpedicular convex anterior hemiepiphysiodesis. The average preoperative curve was 52 degrees. The average age at surgery was 9 years and 1 month and the average follow-up period was 3 years and 6 months. Curve progression was arrested in all cases, and curve correction greater than 10 degrees was achieved in four patients.

Adolescent↗
PubMed1992

Unusual orthopedic manifestations of neurofibromatosis.

Forty-four children with neurofibromatosis were found to have three previously underdescribed conditions: thoracic lordoscoliosis, protrusio acetabuli, and monomelia neurofibromatosis. Thirty-four patients (77%) had scoliosis; of these, nine had dystrophic scoliosis (Group I, 26%), six had dystrophic lordoscoliosis (Group II, 18%), eight had dystrophic kyphoscoliosis (Group III, 24%), and 11 had nondystrophic scoliosis (Group IV, 32%). Group III curves were severe and progressive, rendering them difficult to stabilize even with anterior and posterior spinal fusions. Group II curves were progressive but stabilized by posterior spinal fusion alone. Group I curves were less progressive than Groups II and III, but required surgery more often than those of Group IV, which were generally controlled by orthoses. Protrusio acetabuli of varying severity occurred in 13 patients (21 hips). Three patients had involvement of a single limb (monomelic neurofibromatosis).

Acetabulum↗
PubMed1991

The limping child.

Evaluation of a limping child requires careful consideration and a basic knowledge of potential problems affecting the child. The most important point is not to miss or delay diagnosis of the septic hip. This is truly an orthopedic emergency. Complaints of knee pain should not throw the physician off the track of a diagnosis of hip disease. It is also important to be aware of how the medical history affects the musculoskeletal system. Many causes of limp are best analyzed by repeat examination and stepwise laboratory and radiographic evaluation. One should realize that a painful limp can be caused by something as mundane as a thorn in the heel or as serious as a tumor of the spine: Be suspicious.

Bone Diseases↗
PubMed1991

Growth disturbance of the proximal part of the femur after treatment for congenital dislocation of the hip.

The radiographs of ninety patients in whom treatment of unilateral congenital dislocation of the hip was complicated by disturbance of growth of the proximal part of the femur were studied retrospectively. All patients were followed until closure of the affected proximal femoral physis. We divided the patients into three groups, according to the degree of vascular insufficiency: patients who had mild vascular insufficiency of the hip, which had little effect on growth; those who had moderate vascular insufficiency, which produces partial arrest of growth; and those who had severe vascular insufficiency, which causes complete arrest of growth. Good correlation was found between the initial degree of vascular insufficiency and the radiographic results at the most recent follow-up. The radiographic signs that were used to predict the extent of physeal involvement were a crescent-shaped epiphysis, medial bowing of the femoral neck (a shorter and more concave curve between the lesser trochanter and the proximal femoral metaphysis [the lateral portion of the Shenton line]), lateral tilting of the capital epiphysis, and premature physeal closure. Signs that were diagnostic of existing physeal involvement were elevation of the greater trochanter and shortening of the affected extremity. The presence and severity of these signs correlated well with the degree of vascular insufficiency. Medial bowing was the most reliable prognostic factor for the determination of the fate of the hip joint at maturity.

Adolescent↗
PubMed1990

Congenital dislocation of the hip.

Early diagnosis and treatment are the keys to a successful result in infants with congenital dislocation of the hip. In the neonatal period, a majority of infants with hips that would later be found to be dislocated can be detected and effectively treated. With the use of ultrasonography to supplement clinical suspicion, the number of children with congenital dislocation of the hip diagnosed in the newborn period should be expected to increase. Repeated examination, especially during the first 6 months of life, can be expected to detect those additional children with congenital dislocation of the hip who were not detected in the nursery. The Pavlik harness has been shown to obtain a successful result in most children younger than 6 months of age while holding the incidence of avascular necrosis to nearly zero. Even though these results are encouraging, the problem must be discovered early for the child with congenital dislocation of the hip to be treated optimally. Thus, it is of the utmost importance that the physician have an awareness of this problem. The primary physician must also continue to conscientiously examine the hips of patients on a regular basis even after the initial examination and, when necessary, use the added modalities available to him or her to accurately diagnose questionable hip conditions of patients.

Female↗