A Study Examining Changes in Pain After Manual Therapy in People With Achilles Tendon Pain

While healthcare's understanding of sensory processing changes has grown significantly in the last several years, numerous gaps in the literature exist. In particular, lower extremity tendinopathies, while common, have not been well studied through the lens of potential sensory sensitizations. The prevalence of Achilles Tendinopathy has been reported to be around 6%, meaning that Millions of individuals in the United States will have these issues at any given time. Historically, clinical management of the condition has been challenging. This study aims to provide data for clinicians to better inform treatment strategies by increasing knowledge of the neurosensory changes that may accompany the condition.

After subjects complete informed consent, they will then answer a brief intake screening form asking for demographic information and symptom history to confirm eligibility. The clinical screening will then be performed to confirm signs of Achilles tendinopathy, namely assessment for tenderness to palpation in the Achilles Tendon, the the Royal London Hospital Test. The Royal London Hospital Test consists of assessing for tenderness in the Achilles tendon with the ankle in a relaxed position, and then again with the subject in maximal active dorsiflexion. A positive test is noted when tenderness is reduced in the maximally dorsiflexed position as compared to the rest state. Once eligibility is confirmed, a subject number will be assigned. Prior to beginning data collection, a random number generation program will be used to determine which subject numbers will be placed into the intervention and control groups. All participants will begin data collection with standardized assessment of heat and cold pain thresholds. Heat and cold pain threshold testing will be performed using the Medoc TSA Air2, with calibration performed before each data collection session. Data collection will be performed in accordance with the protocols set forth by the German Research Network on Neuropathic Pain (DFNS.) Participants will be instructed to press the input button to stop the trial when the heat or cold pain stimulus becomes what each subject would describe as pain or discomfort.

Subjects will be instructed that it is a threshold test, not a tolerance test, thus they are asked to press the stop trial button at the beginning of pain, not at their maximal tolerable amount. All trials will be completed three times with a pre-determined 15 second rest between trials. All three trials will be averaged for data analysis purposes. Subjects assigned to the intervention group will then receive a talocrural joint high velocity, low amplitude thrush mobilization/manipulation. Standardized technique for this procedure involves the subject long-sitting with their back supported on the treatment table. The provider will then passively dorsiflex and evert the ankle to the point at which a joint tension end-feel is obtained.

A small amplitude of movement is rapidly provided by the provider in a caudal direction. The provider may attempt up to three treatment thrust impulses, or until an audible cavitation is heard, indicating joint movement. Even without an audible cavitation, no more than three impulses will be provided. Some research in other body regions indicates that treatment effect is present even in those with whom audible joint cavitation is not noted. (10) Subjects in the control group will receive 1 minute of passive ankle movement into ankle dorsiflexion. The researcher will not move the subject's ankle into a point where tissue stretch/tension is perceived. This will serve as an appropriate sham treatment since it still involves the subjects perception of treatment and includes the hands-on element of manual therapy, without the use of any tissue intervention which would theoretically effect change.

Immediately following the application of the intervention or sham all participants will be re-tested for heat and cold pain thresholds in the same manner utilized at baseline. For ethical purposes, subjects assigned to the control group will also receive the intervention following data collection.