Summary

Isokinetic strength testing of ankle and sub taller joints after the harvest of Peroneus Longus tendon for cruciate ligament reconstruction shows no significant deficit.

Abstract

Background

The peroneus longus tendon has been used as a graft in orthopaedic reconstruction surgery because of its comparable biomechanical strength with the native cruciate ligaments and hamstring tendon. However, one of the considerations in choosing an autograft is donor site morbidity.
Purpose/Hypothesis:
This study aimed to identify the isokinetic strength of ankle dorsiflexion/plantarflextion and eversion/ inversion. The study hypothesis was that strength measurements will be different between the harvest site and contralateral healthy site.

Methods

Patients who underwent peroneus longus tendon autograft harvest for cruciate ligament reconstructions between March 2018 and December 2019 were included in this study. Patients followed a rehabilitation protocol from the first day after surgery. Ankle and subtalar joints movements and its isokinetic strength measured using biodex system 3 isokinetic dynamometer at one year follow up. Donor site morbidity was assessed 6 months and one year after surgery using the VASFA score and American Orthopaedic Foot & Ankle Society (AOFAS) scoring system.

Results

A total of 24 patients (20 male, 4 female; mean age- 32.8 years) fulfilled the inclusion criteria. There was no significant difference in ankle inversion/eversion strength deficit at the donor side compared with the contralateral side (P = .85), with 21 out of 24 patients had less than 10% deficit of contralateral side. Also, there was no significant difference in ankle dorsiflexion and plantar flexion strength at the donor site compared with the contralateral site (P = .51), with 23 out of 24 patient had less than 10% deficit compared to normal side. The mean dorsiflexion strength measured with dynamometer at 60 degree/ sec was 59.65 at involved side where as it was 66.65 in normal side (P=0.001). The mean eversion strength measured at 60 degree/ sec was 17.66 at involved side where as it was 18.36 in normal side (P=0.0001) The 91.6% of patients had excellent results in AOFAS/ VAS score (mean score- 93.7/98.11) at the donor site at one year follow up.

Conclusion

Isokinetic strength of ankle and subtalar joints was similar to those at the contralateral healthy site, with no donor site morbidity. This suggests that the peroneus longus tendon autograft harvest does not significantly alter the foot biomechanics. hence it’s a safer choice of graft for multiple ligament reconstructions.