title: Knee function after operation for malignancy of the distal femur. Quadriceps muscle mass and knee extension strength in 21 patients with hinged endoprostheses.
abstract: We evaluated quadriceps muscle mass and knee extension strength in 21 patients after resection and endoprosthetic replacement of the distal femur for malignant bone tumor. In all cases, a modular cementless, hinged prosthesis had been used. The mean follow-up period was 4 (2-9) years. Muscle mass was measured ultrasonographically, and strength isokinetically with a Cybex 6000 dynamometer. All the data for the operated side are given as percentage of the non-operated side. The average quadriceps mass was 48 (27-70) percent. The average peak torque was 31 (14-48) and 36 (18-55) percent at the speed of 30 degrees/s and 90 degrees/s, respectively. The reduction in extension strength became greater with increasing flexion. There was a moderate correlation between muscle mass and muscle strength. Most of the patients who had kept more than 40 percent of the quadriceps mass had more than 30 percent peak torque. Patients with excellent function (Enneking 1987) had more quadriceps muscle mass and higher strength than those that were merely good with the borderline at about 40 percent muscle mass.
authors.affiliation: Department of Orthopedics, University of Vienna, Austria.
authors.forename: T
authors.initials: T
authors.lastname: Tsuboyama
authors.forename: R
authors.initials: R
authors.lastname: Windhager
authors.forename: W
authors.initials: W
authors.lastname: Dock
authors.forename: T
authors.initials: T
authors.lastname: Bochdansky
authors.forename: T
authors.initials: T
authors.lastname: Yamamuro
authors.forename: R
authors.initials: R
authors.lastname: Kotz
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000886:Anthropometry; D002648:Child; D005260:Female; D005266:Femoral Neoplasms / Q000534:rehabilitation / Q000601:surgery*; D005500:Follow-Up Studies; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D007720:Knee Prosthesis / Q000534:rehabilitation; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction; D009132:Muscles / Q000033:anatomy & histology; D016059:Range of Motion, Articular; D014945:Wound Healing