Abstract
Insertional Achilles tendonitis is an inflammatory disorder affecting mainly active young patients. The etiology is multifactorial and include the combination of anatomical and biomechanical characteristics. One fifth of the tendon injuries in athletes are insertional complaints which includes bursitis and insertion tendinitis.The complex of the insertion of the Achilles tendon includes three main components of fibrocartilage sesamoid, periosteum and enthesis. A conservative regime is recommended as the first line of treatment. In case of failure a surgical decompression of the posterior margin of the calcaneum is indicated.
Nine cadaveric legs were used for the experiment. The leg was mounted on an MTS machine and was axially loaded 360 N. The foot was attached to a plate which enabled dorsal and plantar flexion. The Achilles was sutured twice in an Ethibond No. 5 using the Krakow technique in order to anchor the tendon to an actuator. A thin pressure sensor plate (Teckscan) was inserted into the retrocalcaneal bursa to measure the force, pressure and contact area of the Achilles to the calcaneus in various positions of the foot. The conditions included 90 degrees of the foot, 15 and 30 degrees of dorsiflexion while the tension that was applied on the Achilles was 0, 200 N and 300 N. After resection of the posterior surface of the calcaneus in a 20 degrees inclination.
The mean peak force, pressure and area did not change in Achilles tensioning while the foot was in 90 degrees and were close to zero. In 15 degrees of dorsiflexion there was increase in the mean peak force, pressure and area when the Achilles was tensed to 200 and 300 Newton. Larger increase in these parameters was achieved by further dorsiflexion of the foot to 30 degrees.
After resection of the posterior margin of the calcaneus in an angle of 20 degrees the mean peak force, pressure and area dropped close to zero and remained almost unchanged during the various conditions of the experiment.
Dorsiflexion and tension of the Achilles tendon increases the mean peak force, pressure and area in the Achilles retrocalcaneal bursa. These data may explain the mechanism for insertional Achilles tendinosis. Resection of the posterior surface of the calcaneus in 20 degrees efficiently decompresses the retrocalcaneal bursa in various angles of the foot and in various tensions of the Achilles.
The abstracts were prepared by Mr J. L. Barrie. Correspondence should be addressed to Mr J. L. Barrie, BOFSS Editor, Department of Orthopaedic Surgery, Blackburn Royal Infirmary, Blackburn, Lancashire BB2 3LR.
