- Discussion:
- see Arthrex, Mitek, Linvatec, Smith-Nephew
- in choosing a fixation technqiue consider the need for the following:
- circumferential (360 deg) healing of graft against tunnel wall (interference screws do not permit this);
- bioabsorbable material
- strong initial fixation (greater than 120-140 Newtons)
- interference screw insertion:
- typically a 8 x 25 mm screw will be selected;
- nitinol guide wire can be inserted thru the medial arthroscopic portal, or may be inserted thru a stab incision made in fat pad, below the portal;
- knee is flexed an additional 30 deg to facilitate insertion of Nitinol guide wire;
- a sheath is required to protect the tendinous portion of the graft from the screw threads;
- appropriate graft tension:
- usually about 40 N or 10 lbs of tension is applied;
- typically graft is secured in 20-30 deg of knee flexion;
- references
- Initial tension and anterior load-displacement behavior of high-stiffness anterior cruciate ligament graft constructs.
- A prospectively randomized double-blind study on the effect of initial graft tension on knee stability after anterior cruciate ligament reconstruction.
- Viscoelasticity and temperature variations decrease tension and stiffness of hamstring tendon grafts following anterior cruciate ligament reconstruction.
- Effects of initial graft tension on the tibiofemoral compressive forces and joint position after anterior cruciate ligament reconstruction.
- Effects of initial graft tension on clinical outcome after anterior cruciate ligament reconstruction. Autogenous doubled hamstring tendons connected in series with polyester tapes.
- The effect of initial graft tension in anterior cruciate ligament reconstruction on the mechanical behaviors of the femur-graft-tibia complex during cyclic loading.
- A survey of the tension applied to a doubled hamstring tendon graft for reconstruction of the anterior cruciate ligament
- Graft tension in anteror cruciate ligament reconstruction. An in vivo study in dogs.
- Effect of Different Preconditioning Protocols on Anterior Knee Laxity After ACL Reconstruction with Four Commonly Used Grafts
- Pretensioning of Soft Tissue Grafts in Anterior Cruciate Ligament Reconstruction.
- degree of knee flexion during fixation:
- if patient has gross instability to lachman and pivot shift then tensioning at 15 lbs at 30 deg is indicated;
- if patient has hyperextension of the knees on both sides or if graft tightens or shortens 5 mm or more with knee extension, then
tension closer to full extension;
- dual fixation
- using the same concept as double tunnel reconstruction, consider fixation of the 2 posterior hanstring ends with a staple at 15 deg flexion,
and then interference screw fixation at 40 deg flexion;
- references:
- Loss of Knee Extension After Anterior Cruciate Ligament Reconstruction: Effects of Knee Position and Graft Tensioning
- references:
- Reconstruction of the anterior cruciate ligament using bone-patellar tendon-bone graft with double biodegradable femoral pin fixation.
- The effect of soft-tissue graft fixation in anterior cruciate ligament reconstruction on graft-tunnel motion under anterior tibial loading.
- Is Supplementary Fixation Necessary in Anterior Cruciate Ligament Reconstructions?
- Effect of PEEK Polymer on Tunnel Widening After Hamstring ACL Reconstruction