Introduction: Callus distraction during leg lengthening procedures often leads to a reduction in muscle strength. This study explores whether this decline is temporary or if it persists long-term, with a follow-up period of 10 years. Materials and methods: A cohort of nine patients underwent femoral lengthening with a motorized intramedullary device. We measured the maximum isokinetic concentric torque of the knee extensors and flexors preoperatively, at 2 years and at 10 years postsurgery. For this analysis, we included all patients with a full dataset and a minimum follow-up of 10 years ( n = 9). We analyzed the differences between preoperative and postoperative maximal isokinetic torques and compared them with a control group of 10 healthy individuals. Results: Before surgery, the median maximal isokinetic torque of the extensor group was higher in the unaffected leg compared to the shorter leg. After leg lengthening, the difference in extension torque between the unaffected and the lengthened legs increased at the 2-year follow-up and even more after 10 years. In contrast, no change was observed in the knee flexor group and there was no significant loss of maximal isokinetic torque in the lengthened leg. In the control group, the comparison between the dominant and nondominant leg showed a difference in knee extension torque of 2.9% and in knee flexion torque of 1.7% in favor of the dominant leg. Conclusion: Distraction of the muscle appears to have a higher long-term impact on the muscle properties than previously thought.
Speth et al. (Thu,) studied this question.