Use of pulsed electromagnetic fields in treatment of loosened cemented hip prostheses. A double-blind trial.

A double-blind trial of pulsed electromagnetic fields (PEMFs) for loosened cemented hip prostheses was conducted at two centers. Of the 40 patients who enrolled, 37 met entry criteria and were available for analysis. All patients completed six months of treatment (either active or control units). Success was determined clinically by a Harris hip score greater than or equal to 80 points (or an increase of ten points if initially greater than or equal to 70 points). Ten of the 19 active units were successes (53%), whereas two of the 18 controls (11%) exhibited a placebo effect, a statistically significant and clinically relevant result. A 60% relapse rate among the active successes was seen at 14 months poststimulation, and despite maintenance therapy of one hour per day, the relapse rate increased to 90% at three years. These data suggest that for loosened cemented hip prostheses, use of PEMFs is a treatment option only to delay revision hip surgery.

Epiphyseal stapling for angular deformity at the knee.

Fifty six patients with angular deformities of eighty-two knees were treated with epiphyseal stapling between 1954 and 1973 and followed until maturity. There were sixty-four knock-knees and eighteen bowlegs. In twelve patients with concurrent leg-length discrepancies, long legs were stapled asymmetrically. The deformities were allowed to overcorrect before the staples were removed, but the rebound phenomenon occurred in twenty-two patients with thirty-five deformities. In older children the staples were taken out when the legs looked straight. Exaggerated physiological deformities may correct spontaneously. They should not be stapled before the skeletal age of eleven in girls and twelve in boys. Secondary deformities are corrected earlier. There were no significant complications. Ten revisions of staples were necessary because of extrusion or shifting. The results were satisfactory or improved in 87 per cent of the deformities. When it is indicated epiphyseal stapling is a safe and effective method of correcting angular deformity at the knee in growing children.

Comparison of functional performance after McKee-Farrar, Charnley, and Muller total hip replacement. A six-month follow-up of one hundred sixty-five cases.

Measurements of functional performance were compared before and at 6 months after 58 McKee-Farrar, 50 Charnley, and 57 Muller total hip replacements in 143 patients. The measurment included: range of motion of the hip, hip abductor and adductor-muscle torque, weight-bearing activity during standing, forces applied to canes or crutches, and multiple components of walking performance. Each group of patients improved significantly after surgery in all of the components measured. Early postoperative differences among the 3 groups were found with respect to pain ratings, impressions of hip status, hip motions, muscle torque, the number of patients using assistive devices, and certain components of walking performance. There is nothing to suggest that the performance of any 1 group is distinctly better or worse than that of any other group 6 months after surgery. On the basis of average values, each group improved in every component of function and it is gratifying that, except for a few patients who developed postoperative infection, each patient could be considered to have successful reconstruction.

Kinesiology after McKee-Farrar total hip replacement. A two-year follow-up of one hundred cases.

Measurements of functional performance were made before and at six and twenty-four months after 100 McKee-Farrar total hip replacements in eighty-three patients. The measurements included: range of motion of the hip, hip-muscle torque, weight-bearing activity during standing, forces applied to canes or crutches, and multiple components of walking performance. In the absence of serious complications, most patients had improvement in most components of function, with greater gains occurring during the first six months and lesser but continued gains between the sixth and twenty-fourth postoperative months. Patients with serious operative complications, postoperative infections, or component loosening showed declines in almost every component of function tested.