ANTERIOR CRUCIAL LIGAMENT RUPTURE – HEALING THROUGH DYNAMIC INTRALIGAMENTARY STABILIZATION (DIS)

Abstract

Introduction: Ruptured anterior cruciate ligaments (ACL) are generally thought not to heal after treatment so that the ligament must be replaced by a graft. We developed and evaluated a surgical technique that restores knee stability using the self-healing capacity of the ruptured ACL.

Methods: The ACL was cut close to the femoral insertion in 14 sheep. The contralateral, nonoperated side served as the control. After microfracturing at the femoral foot print, the ACL was stabilized using the dynamic intraligamentary stabilization (DIS) technique. A strong intraligamentary suture was attached on the femoral side with a button and on the tibial side by means of an intraosseous spring-loaded screw with a preload of 85 N. In 7 of 14 sheep the ruptured ligament was covered with a collagen membrane. The joint was not immobilized postoperatively. Histological evaluation, magnetic resonance imaging (MRI) and biomechanical testing were performed after 3 months.

Results: Three days postoperative all animals showed no lameness and regularly used the operated leg. Macroscopically, all repaired ACLs appeared healed. Histological and MRI examinations confirmed the healing response of the ACL after DIS. The collagen membrane exhibited a more hypertrophic scare tissue reaction. Biomechanical testing showed an average increase of the operated anterior drawer 2.4 mm (range 0 mm – 4.5 mm) greater than on the control side. No lesions of the meniscus and cartilage were detected.

Conclusions: A ruptured ACL has the biological potential to heal after DIS in a sheep model. The surgical technique achieved a stable knee joint with free range of motion and full weight bearing during the healing period without signs of osteoarthritis or other intraarticular damage at follow up.