Cruciate Ligament Repair with Nitinol Wire Synthetic Allograft

Objectives: To present two cases who underwent cruciate ligament repair by nitinol wire synthetic allograft and to discuss outcomes. Methods: Although definitive incidence of anterior cruciate ligament injuries is unknown, it is estimated that annual 200.000 rupture occurs with 100.000 reconstructions in United States [1]. Therapeutic options include medical treatment, isolated or augmented anterior cruciate ligament repair and reconstruction with autograft, allograft and synthetic grafts. Debates on the treatment of such injury focus on selection of graft rather than need for surgery. Once anterior cruciate ligament reconstruction was decided, surgeon should have to select a graft. In general, an autograft is preferred. There are also allograft and synthetic grafts. Autograft have advantages of low risk for cross-inflammatory response and lack of risk for disease transmission. Nitinol is a material produced from nickel and titanium. It is more often used in vascular stents, orthodontic wires, implants used in mandible surgery and some orthopedic implants [2]. We presented 2 patients who underwent reconstruction with synthetic grafts produced from flexible nitinol wire. Results: Case 1: A 31-year old man presented to our clinic with pain at right knee. The patient underwent cruciate ligament surgery 10 years ago at another facility. His right knee was sprained again 12 months ago; thus, he was re-operated ad anterior cruciate reconstruction was performed in a facility. The patient had pain after surgery. On the physical examination, there was limitation in knee flexion by 100 degree and in knee extension by 10 degree at the right. It was seen that there was painful knee movements. It was found that there was tenderness at medial joint space and patellofemoral grind test was positive while Lachman and anterior drawer tests were negative. On the plain radiographs, it was observed that reconstruction was performed by using flexible nitinol wire synthetic graft and that occasional fractures in nitinol wire existed. The patient accepted removal of graft when he was informed. Thus, we removed flexible nitinol wire synthetic graft and interference screw. In the arthroscopic examination, it was seen that there was grade 4 cartilage defect in patellofemoral joint with occasional fracture in flexible nitinol wire synthetic graft. Endo-button was localized at suprapatellar pouch and removed via artrhroscopy. Micro-fracture procedure was performed for cartilage defect. The patient was scheduled for physical therapy after surgery. After 3 months, it was seen that complaints were resolved and he had almost full range of motion without instability signs. Case 2: A 23-year old man presented to our clinic with pain at right knee. He reported that his knee was injured during sports 9 months ago and he underwent anterior cruciate ligament reconstruction in another facility. However, he had persistent pain. On the physical examination, it was seen that there was full range of motion at knee but diffuse knee pain in hyperflexion. It was seen that medial McMurray test was positive and there was tenderness at medial joint space while Lachman and anterior drawer tests were negative. On the plain radiographs, it was observed that reconstruction was performed by using flexible nitinol wire synthetic graft and that occasional fractures in nitinol wire existed. Revision surgery was recommended but the patient didn’t attend control visit. Conclusion: Orthopedic surgeons tend to have appreciation against novel instruments; however, novel techniques should be adopted by meticulously considering outcomes without fascinating. It is clear that use of synthetic grafts without sufficient experimental and biomechanical in vivo and in vitro studies will result in some complications.