Muscle metabolism during tibial lengthening with regular and high distraction rates.

ABSTRACT

INTRODUCTION: Muscle regeneration is promoted when the Ilizarov method is used for limb lengthening and deformity correction, but the regenerative ability of muscles decreases when achieving large amounts of elongation. Much research has been dedicated to studying the capabilities of muscles under lengthening, but no reports are available that investigate the muscle metabolism. We supposed that energy turnover would be activated in skeletal muscles under lengthening as a response to distraction, and the activity of the energy turnover would grow in proportion to the increase in the distraction rate or amount. MATERIALS AND METHODS: We compared the metabolism of canine anterior tibial muscles (ATMs) by regular and 3-mm high-frequency bone distraction in 30 dogs to obtain 14.5 ± 0.8% lengthening from the initial tibial length. Group 1 (n = 12) had manual lengthening with a rate of 1 mm per day. Three millimeters per day was produced with 120 increments in automated mode in group 2 (n = 12). An intact group (n = 6) served as controls. ATMs were harvested at the end of distraction, after 30 days of fixation, and 30 days after frame removal. We assessed the activity of lactate dehydrogenase, creatine phosphokinase, glucoso-6-phosphate dehydrogenase, and catalase and calculated the concentration of malone dialdehyde, sarcoplasmic and contractile proteins in the ATM extract. RESULTS: Energy turnover reactions were activated in the ATM as a response to distraction forces, but the activity of the energy turnover did not grow proportionally to the increased distraction rate. Levels of sarcoplasmic and contractile proteins in the ATM decreased insignificantly in both groups. CONCLUSIONS: High-frequency 3-mm daily lengthening results in compensatory energy turnover changes in the muscle, sufficient for prevention of catabolic processes.