Objective: To report the outcome of surgery for chronic recalcitrant Achilles tendinopathy in sedentary and athletic subjects.

Design: Case control study

Participants: We matched each of the 61 non-athletic patients with a diagnosis of tendinopathy of the Achilles tendon with an athletic patient with tendinopathy of the main body of the Achilles tendon of the same sex who was within two years of age at the time of operation. A match according was possible for 56 patients (23 males and 33 females). 48 sedentary subjects and 45 athletic subjects agreed to participate.

Main Outcome Measure: Outcome of surgery, return to sport, complication rate.

Results: Non-athletic patients were shorter and heavier than athletic patients. They had greater BMI, calf circumference, side-to-side calf circumference differences, and subcutaneous body fat than athletic patients. Of the 48 sedentary patients, only 25 reported an excellent or good result. Of these, three had undergone a further exploration of the Achilles tendon. The remaining patients could not return to their normal levels of activity. In all of them, pain significantly interfered with daily activities.

Conclusions: Non-athletic subjects experience more prolonged recovery, more complications, and a greater risk of further surgery than athletic subjects with recalcitrant Achilles tendinopathy. Key words: Achilles tendinopathy, surgery.

Purpose To ascertain whether there are differences in the histopathological appearance of tendinopathic Achilles and patellar tendons.

Methods In males, we studied biopsies from tendinopathic Achilles (n = 28; average age 34.1 years) and patellar tendons (n = 28; average age 32.1), and Achilles tendons (n = 21; average age 61.8 years) from deceased patients with no known tendon pathology, and patellar tendons (n = 15; average age 28.3) from patients undergoing anterior cruciate ligament reconstruction. Haematoxylineosin stained slides were interpreted using a semi-quantitative grading scale (0: normal to 3: maximally abnormal) for fibre structure; fibre arrangement; rounding of the nuclei; regional variations in cellularity; increased vascularity; decreased collagen stainability; hyalinisation. All slides were assessed blindly twice, the agreement between two readings ranging from 0.170 to 0.750 (Kappa statistics).

Results The highest mean score of tendinopathic Achilles tendons was not significantly different from that of tendinopathic patellar tendons (11.6 ± 5 and 10.4 ± 3, respectively). The ability to differentiate between an Achilles tendon and a patellar tendon was low.

Conclusions Tendinopathic Achilles and patellar tendons show a similar histological picture. It was not possible to identify whether a specimen had been harvested from an Achilles or a patellar tendon on the basis of histological examination. The general pattern of degeneration was common to both tendinopathic Achilles and patellar tendons. A common, as yet unidentified, etio-pathological mechanism may have acted on both these tendon populations.