Do Patients With ACL Tears Demonstrate Weakness of 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.

Inclusion criteria

ACL tear participants:

• MRI-confirmed ACL tear.
• Participant is willing and able to give informed consent in writing for participation in the study.
• Male or Female, aged 18 years to 55 years of age.
• No contraindications to strength testing (see exclusion criteria).

Normative values from healthy individuals:

• No current or previous history of significant lower limb injury, or a history of previous minor injury that is symptomatic at the time of recruitment.
• No previous lower limb surgery.
• No course of medication, whether prescribed or over the counter, other than vitamins and mineral supplements or, for females, oral contraceptives.

Exclusion criteria

• History of chronic musculoskeletal disease or disorder in either leg that may put the participants at risk because of participation in the study including non-united fractures, epilepsy, cardiac insufficiency, severe peripheral vascular disease, aneurysms, anticoagulant therapy, recent (<3 months) radiotherapy or chemotherapy, long term steroid use (>3 months), pregnancy, neurological disorders (e.g., Parkinson's disease), skin conditions at point of force testing, severe osteoporosis, malignancy, rheumatoid arthritis.

• Conditions or symptoms that may influence the result of the study, or the participant's ability to participate in the study including pain, limited range of motion, knee effusion, or anaemia.