J Appl Physiol (1985). 2025 Nov 20. doi: 10.1152/japplphysiol.00623.2025. Online ahead of print.
ABSTRACT
Limb lengthening procedures are predicated on bone health, with little consideration for soft tissues. For instance, a distraction rate of 1 mm/day is conventionally prescribed to patients based on bone remodeling, with little regard for muscles. Non-human animal studies suggest that the use of slower than conventional distraction rates mitigate muscle damage and the decline in joint function, but such human data are elusive. Accordingly, we compared the knee function (range of motion and strength) of patients who underwent femoral lengthening at a conventional or slower distraction rate (Avg SD; 0.91 0.13 or 0.54 0.15 mm/day, respectively) at terminal distraction and 87 days post initial surgery. Both groups were of similar age (d = 0.10, p = 0.425) and underwent similar lengthening magnitudes (d = 0.12, p = 0.671). At terminal distraction phase, the slower versus conventional distraction rate group exhibited a 56% greater recovery in knee range of motion (d=1.25, p=0.008) and 44% greater knee extensor strength (d=1.02, p=0.046). At the same mutual day post-surgery, despite not achieving statistical significance, the slower versus conventional distraction rate group exhibited a 39% greater recovery in knee range of motion (d=0.48, p=0.180) and similar knee extensor strength (d=0.11, p=0.430). Despite our meager sample size, employing a slower than conventional distraction rate in limb lengthening patients elicited superior joint function at terminal distraction and numerically better joint function at ~3 months post-surgery. Therefore, considering muscle health, in addition to bone health, when devising limb lengthening procedures may expedite patient recovery.
PMID:41263148 | DOI:10.1152/japplphysiol.00623.2025
