Achilles Pain Block

Phase 2

Completed

Brief Summary: The purpose of this study is to better understand how the peripheral and central nervous system interact to produce the sensation of pain and motor patterns in patients with achilles tendinopathy (AT). These findings will motivate the development of future clinical studies that incorporate knowledge about pain processing and movement strategies in patients with tendinopathy. Participants with achilles tendinopathy will receive an anesthetic injection to the achilles tendon in order to examine how reduced pain, detected by the peripheral nervous system, alters task performance and perception of pain. We hypothesize that there are factors within the central nervous system that contribute to continued pain and disability in patients with chronic AT.

Detailed Description: Twenty three people with Achilles tendinopathy (AT) and 23 people without AT will participate in this single visit clinical study. Participants will rate their pain with pressure to the heel, leg and elbow, climb stairs and perform a novel task in a motion capture system, and complete questionnaires on how pain affects their daily life. All subjects will complete these measures twice, and for participants with AT they will complete this battery of tests before and after an anesthetic injection to the area of pain. This study has 2 aims:

Specific Aim 1 compares measures of altered central processing in patients with chronic AT to adults without chronic pain; we hypothesize that patients with chronic AT will demonstrate signs of altered central processing, including central sensitization (lower pressure pain threshold), psychosocial factors (higher kinesiophobia), and/or altered motor control (lower ankle power during stair ascent).

Specific Aim 2 determines which indicators of altered central processing persist after a local anesthetic injection to the Achilles tendon in patients with chronic AT; we hypothesize chronic AT pain is perpetuated by altered central processing that persists in the absence of continued peripheral nociception.

Recruitment & Eligibility

Inclusion Criteria

Clinical diagnosis of chronic (>3 months) AT, consisting of pain with pressure at the achilles tendon and report of pain that is aggravated by physical activity

Exclusion Criteria

History of foot or ankle surgery, bilateral lateral epicondyle tendinopathy
Comorbidity that would be aggravated by placing hand in water (Raynaud's, thoracic outlet syndrome)
Comorbidity (e.g. stroke, neurological disorder) that limits ability to participate in exercise
Comorbidity (e.g. rheumatic disease, fibromyalgia) that contributes to pain with activity
Peripheral neuropathy
Previous adverse response to a local anesthetic injection
Are pregnant
Are a ballroom dancer

For control participants

Inclusion Criteria:

Exclusion Criteria:

No history of tendinopathy
No condition that limited activity in the past 6 months
History of foot or ankle surgery, bilateral lateral epicondyle tendinopathy
Comorbidity that would be aggravated by placing hand in water (Raynaud's, thoracic outlet syndrome)
Comorbidity (e.g. stroke, neurological disorder) that limits ability to participate in exercise
Comorbidity (e.g. rheumatic disease, fibromyalgia) that contributes to pain with activity
Peripheral neuropathy
Are pregnant
Are a ballroom dancer

Arm && Interventions

Group	Intervention	Description
Group with Achilles Tendinopathy	Ropivacaine injection	Ropivacaine injection. While looking at the Achilles tendon with ultrasound, the orthopaedic physician will inject 4 mL of 0.5% ropivacaine (numbing medicine) around the area of pain. The needle may be directed just under the skin (and above the tendon) and/or deep to the tendon.

Primary Outcome Measures

Name	Time	Method
Central Sensitization	Within session, baseline and 30 minutes after an anesthetic injection	Pressure pain threshold (PPT) at heel on contralateral side. A pressure algometer (Somedic, Farsta, Sweden) was applied perpendicular to the skin at a rate of 50 kilopascal/s with a 1cm2 tip. The participants pressed a button when the sensation of pressure first became painful (1/10 on NPRS). The mean of 3 trials per area represented the PPT.
Pain Psychology	Within session, baseline and 30 minutes after an anesthetic injection	Tampa Scale of Kinesiophobia (TSK, score range 17 to 68). A decrease in TSK would indicate a decrease in fear of injury (and/or re-injury)
Movement System	Within session, baseline and 30 minutes after an anesthetic injection	Change in peak ankle power during the stance phase of gait during stair ascent, which will be assessed by syncing movement data from 3-dimensional motion analysis with ground reaction force data from a force plate. Peak positive ankle power reflects the ability of the plantar flexor muscles to concentrically generate speed and force at the ankle joint.