Residual Asymmetries In Functional Achilles Tendon Loading Following Rupture And Repair: A Preliminary Analysis

PURPOSE: Long-term functional deficits are common following Achilles tendon (AT) rupture.1 Such deficits may arise from impaired muscle-tendon force production. This study leveraged advances in shear wave tensiometry2 to directly assess functional AT loading during locomotion following rupture and repair. METHODS: Seven participants (3 males; 46 ± 8 years old, 24 ± 9 months post-surgery) have been enrolled in this IRB approved study. Participants completed an AOFAS Ankle/Hindfoot survey. Tensiometers were secured bilaterally over the ATs. Participants walked overground while tendon wave speed, whole body kinematics, and ground reactions were recorded. For each participant, normalized tendon wave speeds over stance phase were bilaterally compared using statistical parametric mapping. AOFAS scores between limbs were compared using two-tailed paired t-tests. RESULTS: A subset of participants (4/7) exhibited decreases in normalized wave speed during ~20-60% of stance phase (12-42% reduction at 40%) on the injured side (Fig 1). Among those participants, there was a tendency for reduced ankle dorsiflexion and ankle plantarflexion moment. AOFAS scores were lower for the injured side (95CI diff = -12.3,-0.9, p = 0.03, d = 1.06). CONCLUSION: Tensiometry revealed long-term asymmetries in tendon loading in a subset of participants who underwent AT rupture and repair. The lower wave speed in the injured side is indicative of reduced tendon loading and may arise from an elongated tendon that does not engage normally with dorsiflexion. Given some subjects did not exhibit asymmetries, the long-term behavior may be modifiable. We have recently introduced a wearable version of tensiometry3 that could be used to longitudinally assess functional recovery to identify treatment factors that can best restore function. REFERENCES: [1] Zellers+, AJSM, 2021. [2] Martin+, N Com, 2018. [3] Harper+, Sen, 2020. FUNDING: Funded by the MCW, NIH (R42AR074897), DOD (129866603), and WARF.