Background
One potential complication of interference devices to fix anterior cruciate ligament (ACL) grafts is divergence between the implant and the graft-tunnel. Tunnel-screw divergence >15-30 degrees significantly reduces graft-tunnel fixation and may compromise the stability of the knee.
Material and Method
A complication of the IntraFix device is presented. A 43-year-old male sustained a primary ACL reconstruction. The autologous hamstring graft was fixed in the tibia with the IntraFix device. The procedure went without apparent incidents or complications. During postoperative follow-up he developed pain and crepitus over the anteromedial aspect of the operated knee. A flexion contracture slowly developed up to 10 degrees and did not improve with aggressive physiotherapy. At eight postoperative weeks, second-look arthroscopy was performed. The intraoperative findings were a healthy-looking ACL graft and a grade III chondral injury in the medial femoral condyle (MFC) caused by the tip of the IntraFix device, which protruded through the medial tibial plateau. During flexion-extension motion of the knee, the tip eroded the chondral surface of the MFC. This was treated with mechanical and thermal chondroplasty and the tip of the IntraFix device was burred flat to match the surface of the medial tibial plateau. The patient's symptoms improved.
Results

Conclusions
Divergence of the interference screws in the femur is not uncommon, but on the tibia it is rare. Although this technical error did not affect stability, it did produce intrarticular injury. Strict adherence to the surgical technique is recommended and several hints on how to avoid complications with this implant are suggested.

Keywords: Tibia - surgery, Tissue Transplantation - methods, Tendons - transplantation, Intraoperative Complications - surgery, Cartilage - injuries, Bone Screws - adverse effects, Anterior Cruciate Ligament - surgery