Do Patients With ACL Tears Demonstrate Weakness of the Soleus Muscle?

Overview

The goal of this prospective, cross-sectional study is to test the strength of the soleus muscle in participants who have a ACL tear confirmed by MRI. Previous studies have shown that the soleus muscle, which one of the muscles situated in the calf, decreases mechanical loading on the ACL. Therefore, we aim to test soleus muscle strength using a seated plantar flexor test. The main questions we aim to answer are: * Do patients with ACL tears demonstrate inter-limb soleus strength asymmetry (\>10%) * Do patients with ACL tears have soleus muscle weakness compared with uninjured (normative) participants? * Do changes in soleus strength values correlate with patient reported outcomes and stability, as measured by the IKDC questionnaire? To achieve this the VALD force frame will be used as the testing device for plantar flexor strength testing. This device records the force generated by the movement. This will be repeated three times on each leg as part of the testing procedure. Furthermore, as part of the testing procedure participants will be required to fill out an IKDC form to assess their knee stability. Interrater reliability of the force frame will be investigated. Further data from participants without ACL tears will be used to compare results. Thus allowing us to see if people with ACL tears have a weakness in the soleus muscle.

To address the research question, we will collect and analyse measures of lower limb muscle strength, which together will inform on the strength/ weakness of the Soleus muscle in patients undergoing physiotherapy rehabilitation following MRI-confirmed ACL injury. Patients identified as eligible according to the protocol inclusion and exclusion criteria will be invited to participate in the study through informed written consent so that their clinical measurements can be used as research data. Healthy volunteers will be identified by direct email invitation or word of mouth. Healthy volunteers will be members of staff at Aintree Hospital, LUHFT. Patients will undergo the clinically established treatment pathway for rehabilitation with lower limb muscle strength and performance measurements taken from isometric seated calf raise using the Vald Forceframe and single leg jump using Vald Forcedecks. Measurements will be performed with maximal ankle dorsiflexion and the knee flexion angle greater than 90 degrees. Three submaximal warmups will be performed followed by three maximum efforts, taking the maximum reading for analysis. Normative values from healthy participants will be collected using the same clinical protocol. Patients and healthy participants will be asked to complete the international knee documentation committee (IKDC) questionnaire at the start and end of rehabilitation, to determine subjective complaints of instability.