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Biomedical subjects

A G MacEachern

Publications and source records attributed to A G MacEachern.

10 recordsLinked to original sources
PubMed2001

Patellar tendon length following opening wedge high tibial osteotomy using an external fixator with particular reference to later total knee replacement.

The aim of this retrospective study was to examine a cohort of patients who had undergone high tibial osteotomy (HTO) using the method of opening wedge hemicallotasis, and who later required conversion to total knee replacement (TKR). The incidence of patella infra and any technical difficulties encountered during TKR operation were examined. A consecutive series of 76 valgus osteotomies in 65 patients were carried out by one surgeon using a dynamic axial fixator (DAF). Later conversion to TKR, required for the progression of symptoms, was carried out in nine knees (seven patients) at a mean time from the initial osteotomy of 7 years (1.5-11). All of those patients who underwent HTO and subsequently required conversion to TKR were followed up. The patellar height was assessed by one observer in all knees pre- and post-HTO using the Insall and Salvati and Blackburne and Peel ratios. Using these criteria, only one case of patella infra occurred. There were no added technical difficulties in performing TKR as a result of the previous osteotomy and clinical outcomes using the Oxford knee score were satisfactory (34 where 48 is maximum).

Adult↗
PubMed2001

High tibial osteotomy using a dynamic axial external fixator.

High tibial osteotomy is an accepted treatment for unicompartmental osteoarthritis of the knee. Conventional osteotomy can be a demanding procedure with potential for complications. Opening wedge high tibial osteotomy using an external fixator is an alternative that may have advantages in comparison with classic methods. The aims of the current study were to determine if opening wedge osteotomy using hemicallotasis techniques is safer than, and the outcome comparable with that of, conventional techniques. Seventy-six high tibial osteotomies were performed in 65 patients for primary osteoarthritis. The mean age of the patients was 54.8 years (range, 36-70 years). The mean followup was 6 years. The only serious complication occurred in one patient, who had chronic osteomyelitis develop 2 years after surgery. There were no neurologic or vascular complications. The authors think this technique is safer than conventional techniques. Survivorship at 5 and 10 years was 89% and 63%, respectively. The mean knee score in osteotomies was 26.6 (maximum possible score, 48). The outcome is comparable with, or better than, that of other techniques for osteotomy. Subsequent knee replacement, in cases requiring conversion, was straightforward. The mean score in knees that had osteotomies that were converted to total knee replacements was 33.7.

Activities of Daily Living↗
PubMed1990

Reduction of post-traumatic swelling and compartment pressure by impulse compression of the foot.

Following the discovery of a powerful venous pump in the foot that is activated by weight-bearing independently of muscular action, a pneumatic impulse device was developed to actuate this pump artificially. In a multicentre international trial the device was shown to reduce post-traumatic and postoperative swelling; pain also was alleviated. Evidence is also presented that dangerously high compartment pressures may be reduced to acceptable levels and fasciotomy avoided. We present an explanation of the clinical effects of activation of the venous footpump, based on recent improved understanding of the physiology of the microcirculation. The hyperaemic response that follows the liberation of endothelial-derived relaxing factor (EDRF) by sudden changes of pressure after weight-bearing or impulse compression is particularly important.

Adolescent↗
PubMed1984

Subtrochanteric fractures of the femur through the track of the lower Garden screw--treatment with a Richards sliding screw.

Four cases of subcapital femoral fractures, initially treated by internal fixation with Garden screws and subsequently complicated by subtrochanteric fractures through the lower screw hole, have been successfully treated by substitution of a Richards sliding screw of corresponding angle for the lower screw. All 4 subtrochanteric fractures united without implant failure. One subcapital fracture failed to unite and secondary femoral head replacement was unimpeded.

Aged↗
PubMed1984

Bilateral simultaneous spontaneous rupture of the quadriceps tendons. Five case reports and a review of the literature.

Five cases are presented of bilateral simultaneous rupture of the quadriceps tendon and the English literature of six isolated case reports is reviewed. All the patients were men, and most were over 50 years old. The injury often happens in elderly people and there is diagnostic confusion with other causes of inability to use the legs, notably with mild strokes. In three of our five cases there was a delay in diagnosis. The cardinal features are diffuse swelling around the knee, a visible or palpable suprapatellar defect and the inability to lift the straight leg despite a functioning quadriceps and normal activity in all other muscle groups in the leg. In all our patients operative repair was undertaken, followed by six weeks immobilisation in plaster and subsequent physiotherapy. Even late repair was associated with successful rehabilitation of the patient and a return to useful function.

Aged↗
PubMed1983

Treatment of intertrochanteric fractures of the femur. A comparison of the Richards screw-plate with the Jewett nail-plate.

One hundred and seven patients with intertrochanteric fractures of the femur treated with a Richards screw-plate were compared retrospectively with 103 patients treated with a Jewett nail-plate. The mortality and morbidity were similar in the two groups. In patients with comparable fractures, those treated with a Richards device mobilised more quickly and left hospital sooner, and more of them returned to their homes. Failures of stabilisation, both clinically and radiographically, were fewer in this group. The reliability of fixation with a correctly positioned Richards screw-plate could justify the omission of outpatient follow-up in all but a small group of patients with severe unstable fractures or grossly defective bone stock. The higher cost of a Richards implant and the slightly longer operative procedure were outweighed by savings in occupancy of acute and long-stay hospital beds.

Adult↗
PubMed1983

Stable intertrochanteric femoral fractures. A misnomer?

Intertrochanteric fractures of the femur are usually classified into stable and unstable groups, partly to predict the likelihood of displacement with early weight-bearing after internal fixation. Of 82 internally fixed intertrochanteric fractures which would normally be classified as stable, 25 subsequently underwent impaction along the axis of the nail or screw; varus displacement occurred in another six. Of these 31 fractures, 10 were two-part fractures which had been anatomically reduced, and 12 were originally undisplaced. It did not seem possible to predict the subsequent instability from the pre-operative radiographs. Of the 82 fractures, 47 had been treated with a Jewett nail-plate and 35 by a Richards compression screw-plate. Two groups of stable fractures were recognised: Group 1 was undisplaced and Group 2 displaced. Axial impaction occurred in a quarter of all Group 1 fractures however treated. In Group 2 fractures it occurred in a quarter of those treated with a nail-plate, and in over a third of those treated with a sliding screw-plate. The six fractures that underwent varus displacement had all been treated with Jewett nail-plates. Penetration into the joint occurred in 10 patients, all of them in the group treated with Jewett nail-plates; four required re-operation.

Aged↗