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

Abstract

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.

Femoral lengthening might impair physical function and lead to structural changes in adjacent joints: 10 patients with 27 to 34 years’ follow-up

“…On one hand, we cannot rule out that the difference between the limbs was already present before the lengthening procedure as we do not have preoperative measurements. Preexisting differences have previously been described by Krieg et al (2018), who found that the shorter limb was weaker than the longer both before and 2 years after femoral lengthening. On the other hand, the patients in the study by Krieg et al (2018) could have had etiologies associated with impaired physical function of the lengthened limb, a weakness accounted for by the strict inclusion criteria in our study.…”

“…Even though the results are not unambiguous, 2 of 4 hop tests showed a statistically significant difference between the limbs and half of the patients had impaired physical function of the lengthened compared with the unlengthened limb at assessment. Our results are important as the literature is inconsistent in whether femoral lengthening impacts physical function of the lengthened limb or not (Bhave et al 2017, Krieg et al 2018). On one hand, we cannot rule out that the difference between the limbs was already present before the lengthening procedure as we do not have preoperative measurements.…”

“… 2017 , Krieg et al. 2018 ). On one hand, we cannot rule out that the difference between the limbs was already present before the lengthening procedure as we do not have preoperative measurements.…”

“… 2017 , Krieg et al. 2018 ). Concerns have been raised regarding whether limb lengthening might lead to OA in adjacent joints (Herring 2008 , Sneppen et al.…”

“…However, literature describing the long-term functional outcome and eventual late side effects such as osteoarthritis (OA) in adjacent joints is rare. Previous studies have investigated whether femoral lengthening impacts muscle strength in the lengthened limb, but results are inconsistent (Bhave et al 2017, Krieg et al 2018. Concerns have been raised regarding whether limb lengthening might lead to OA in adjacent joints (Herring 2008, Sneppen et al 2014.…”