This is a prospective cohort study that will follow 60 patients treated with Proximal Medial Gastrocnemius Recession for Chronic Mid-Portion Achilles Tendinopathy for 5 years postoperatively.

Mid Portion Achilles Tendinopathy is a condition that usually resolves by itself without any kind of intervention. If the condition becomes chronic, eccentric training guided by a physical therapist seems to be the best non-surgical intervention. Surgical treatment has shown varying results and no gold-standard exists.

Tightness in the gastrocnemius muscle seems to be a contributing factor for many conditions in the foot and ankle region.

Retrospective material suggest that Proximal Medial Gastrocnemius Recession (PMGR) can be an effective treatment for this condition. No prospective material exists.

This study aims at including 60 patients with Chronic Mid-Portion Achilles Tendinopathy (CMPAT) that is non-responsive to eccentric training. Patients will be PMGR-surgery and followed for 5 years with PROMS, muscle function test and MRI scans.

Inclusion criteria:

1. Age 18-75 years.
2. Diagnosis CMPAT verified clinically by orthopedic surgeon. Symptoms must include mid-portion pain in the Achilles, swelling and reduced tolerance for weightbearing.
3. Verified diagnosis with MRI findings representing pathologic processes of tendon degeneration and repair (13). MRI no older than 12 months.
4. Duration of symptoms must be at least 12 months.
5. Isolated gastrocnemius tightness must be verified with the Silfverskiölds test before inclusion. The Silfverskiöld test is considered positive if ankle dorsiflexion is restricted to 5 degrees or less with the knee extended, and there is an increase of ankle dorsiflexion of at least 10 degrees when flexing the knee.
6. At least three months of conventional physical therapy with eccentric training must have been tried without providing relief of symptoms.

Exclusion criteria:

1. Previous history of complete Achilles tendon rupture.
2. Other combined pathologies in the Achilles tendon of calf (Sequela from trauma, infections, cancer etc.).
3. Insertional Achilles tendinopathy.
4. Previously undergone surgery in affected tendon.
5. Patients with severe talocrural pathology or serious malalignment of foot and ankle.
6. Severely reduced peripheral circulation.
7. History of alcoholism, drug abuse, psychological or other emotional problems likely to jeopardize informed consent.
8. Patients with a contraindication/non-compliance for MRI examination.
9. History of allergic reaction/anaphylactic reaction to local anesthetics.
10. Not able to read and/or speak a Scandinavian language or English adequately.
11. Other serious comorbidity that makes surgery unadvisable.