Methods and rationale for closed treatment of Achilles tendon ruptures

Abstract

Significant recent interest in closed treatment of Achilles tendon ruptures has been noted in the literature, as well as in clinical practice. This interest has grown out of dissatisfaction with operative treatment and its attendant high complication rates. The method of closed treatment consists of a gravity equinus, long leg, slightly bent knee cast for 6 weeks. This is followed by a short leg cast for a period of 4 weeks. A 2-cm heel lift is then used. Closed approximation of the tendon is easily demonstrated at the time of equinus casting. Results obtained have been gratifying. Observations were made on the Achilles tendon in dissected, fresh amputated specimens. Prominent transverse vessels in the paratenon, continuous with those of the anterior mesentery, illustrate well reports of the important role of these vessels in circulation to the midportion of the tendon, and its paratenon sheath is well demonstrated. An experimental study to document and compare closed methods of treatment of Achilles tendon injuries with open surgical methods has been done in mature rabbits. Results of tensile strength analysis at 1, 2, and 3 weeks demonstrate no significant difference between these two modes of treatment; at 3 weeks, tensile strength was 17.25 kg per cm' in the sutured side and 29.95 kg per cm' in the nonsutured side. Macroscopic examination demonstrated early tendon callus formation in all specimens ; this was more prominent in those treated closed where the paratenon was left in place. Surgical repair tended to destroy the paratenon envelope surrounding the tendon. However, an increased tendency toward separation of the tendon ends was seen in the nonsutured specimens ; yet both sutured and nonsutured tendons revealed a linear increase with time of immobilization. Microscopic examination presented clear evidence of progressive tendon healing in both types of specimens. By 24 days, organized fibroplasia can be seen spanning the tendon ends in an impressive fashion. The rationale for closed treatment of Achilles tendon ruptures is well supported through anatomical dissection and demonstration of a vascular paratenon and anterior mesentery. The maintenance of an intact paratenon sheath in nonsurgical treatment favors rapid healing, avoiding the complications of open surgical management. Experimental evidence in rabbits also supports this method of closed treatment as a satisfactory method which allows tendon healing to occur.