Gain of length-loss of strength? Alteration in muscle strength after femoral leg lengthening in young patients: a prospective longitudinal observational study.

This study aimed to determine the alteration in maximum isokinetic torque in patients after intramedullary femoral leg lengthening. Thirty patients with a median leg-length discrepancy of 3.0 cm underwent femoral limb lengthening with an intramedullary motorized device. Maximum isokinetic, concentric torque of the extensors, and flexors of the knee was measured before (n=30) and 2 years after surgery (n=21). Postoperatively, a significant difference remained for the maximum isokinetic torque of the extensors (22%) between the lengthened and the normal leg, which might have been caused by muscle response to the distraction procedure itself in the form of higher stiffness, less immediate displacement, and inconsistent force relaxation properties. However, we provide evidence that physiotherapy after limb lengthening should focus on extensors to prevent loss of strength.

[Biomechanical Evaluation of Rehabilitation after Surgical Repair of Achilles Tendon Ruptures]. / Biomechanische Evaluation des Rehabilitationsverlaufs nach operativer Versorgung der Achillessehnenruptur.

Background Muscles and tendons are subjected to a high level of stress in everyday life and sports. This often leads to injuries and is associated with training failure and reduced performance as well as with high costs for treatment and rehabilitation. Fast and successful treatment is therefore very important, both from an athletic and economic point of view. This study aims to demonstrate the relevance of biomechanical procedures for the objective monitoring of rehabilitation. At the same time, the results are to be used to establish progress and evaluation criteria for an efficient and controlled rehabilitation. Patients and methods In a retrospective study, a total of 42 patients were evaluated biomechanically after surgical repair of a complete Achilles tendon rupture 18 (18 W) and 26 weeks (26 W) postoperatively. Ground reaction forces in barefoot walking on a treadmill as well as isokinetic maximum strength for the plantar flexors and dorsal extensors were assessed. Results The push-off force on the injured side increased from 0.88 (18 W) to 0.95 (26 W). The percentage of heel contact time on the injured side was 59 % at 18 W and 55 % at 26 W. Plantar flexion torque increased from 70 Nm (18 W) to 90 Nm (26 W) on average on the injured side. The percentage of the plantar flexion deficit (injured/non-injured side) decreased from 34 % to 21 % on the two postoperative measuring dates. Conclusions The described biomechanical methods allow for a quantitative assessment and an objective control of the rehabilitation process. The results can also be used for the definition of evaluation and progression criteria in order to assess the progress of a patient's therapy and to guide the rehabilitation process in a controlled manner.