Isokinetic torque deficit of the knee extensor muscles after arthroscopic partial meniscectomy.

Isokinetic torque deficit of the knee extensor muscles in the operated leg was measured in 21 male patients (mean age 26.4 +/- 1.9 years) who had undergone arthroscopic partial medial meniscectomy. The isokinetic torque testing was performed 1, 3, and 6 months postoperatively using the Cybex II dynamometer according to standard technique. Isokinetic knee extension peak torque (PT) at angular velocities of 60 degrees and 180 degrees/s was determined in both legs, and the proportional PT deficit in the operated leg was compared with that in the nonoperated leg. A significant (P<0.001) isokinetic PT deficit in the operated leg in testing with angular velocity of 60 degrees and 80 degrees/s was observed at 1 month (28.6% and 31.0%, respectively) and 3 months (19.8% and 15.8%, respectively) postoperatively. At 6 months postoperatively a significant (P<0.001) isokinetic PT deficit (18.2%) of the knee extensor muscles in the operated leg was observed only in testing with angular velocity of 60 degrees/s; no significant differences (P>0.05) in isokinetic PT between the operated and nonoperated leg in testing with angular velocity of 180 degrees/s was found 6 months postoperatively. Thus in patients with arthroscopic partial meniscectomy the postoperative recovery of isokinetic strength of the knee extensor muscles in the injured leg is closely related to testing velocity, while it is more delayed at low than intermediate angular velocities.

Changes in functional characteristics and myosin heavy chain composition in m. vastus medialis before and after arthroscopy for knee injury.

The aim of this study was to investigate the influence of restriction of movement on the functional characteristics and myosin heavy chain composition of m. vastus medialis. The subjects of this study were 13 arthroscopically treated patients with meniscus lesions (both men and women, mean age 28 years). All measurements were performed and biopsies were taken bilaterally before and 6 months after knee arthroscopy. Thigh girth was measured to determine the degree of atrophy. A tendency towards decreased thigh girth in the injured leg was noted. As an estimate of functional characteristics, maximum voluntary contraction (MVC) was measured. The MVC of the injured limb was lower than that of the non-injured limb (mean values 548.2 +/- 54.1 and 705.4 +/- 48.2 N respectively; P < 0.05). The myosin heavy chain (MHC) composition was determined electrophoretically. The proportion of MHC I isoform decreased from 59.35% to 47.97% (P < 0.05).

Postural corrections after standardised perturbations of single limb stance: effect of training and orthotic devices in patients with ankle instability.

OBJECTIVE: Soccer players with functional instability of the ankle joint have shown impairment of postural control in single limb stance. The aim of this study was to examine the effect of stance perturbation. METHODS: A standardised method for the study of postural corrections after perturbation (Equitest) was used. Female soccer players with and without functional instability were examined. RESULTS: The subjects showed a relative change from ankle to hip synergy at medially directed translations of the support surface. This impairment was restored after eight weeks of ankle disk training. The effect of a shoe and brace did not exceed the effect of the shoe alone. CONCLUSIONS: Functional instability seems to be related to impaired ability to retain equilibrium in single limb stance by means of ankle corrections. A positive effect of ankle disk training leading to functional restoration was confirmed.