Orthozip / Lateral Suture Starting at $2500
Extracapsular suture repair for the treatment of unstable stifles due to cranial cruciate ligament insufficiency has been around for decades and has helped tens of thousands of dogs. Although osteotomy techniques like TPLO and TTA have become the standard of care for large breed and athlete dogs, the extracapsular repair has remained a very useful technique that can be done in your hospital when referral is not an option.
Because of the frequent use of this procedure, modifications have been made over the years to address the weaknesses of the original technique. The development of a tensioning and crimping system with nylon leader line was a quantum improvement over the original hand-tying system. Ongoing improvements have focused on increasing the strength and limiting the stretch of the implanted material; increasing the strength of the anchoring points, and maximizing isometry so the suture is uniformly tight during the entire range of motion. There are a number of new systems currently marketed to veterinarians that have incorporated these new features. However, It is important to remember that all these techniques are still mechanically extracapsular repairs. As such, they mechanically constrain the tibia from subluxating cranially and also nearly eliminate the normal internal rotation of the tibia.
Most of the newer implants, whether a suture, tape, or loop are made of ultra-high molecular weight polyethylene. This material is much stronger than nylon leader line and does not stretch. The anchoring points are bone tunnels with buttons or interference screws, screw-in anchors with holes or flanges, or screw-in anchors with the material already attached. The implants are placed so that they counter the force of subluxation from the isometric points that have been identified on the distal femur and proximal tibia.
The Everost OrthoZIP system was developed by the same bio–engineer that created the original nylon leader line tensioning and crimping system. This system employs a self tightening ultra-high molecular weight polyethylene loop that is placed over titanium anchors with a cancellous thread profile and a “sewing-bobbin” shaped head to retain the loop. After arthrotomy and inspection and treatment of any meniscal injuries, the anchor points are identified, pre-drilled, and the anchors placed. Then the loop is placed over the anchors and tightened by pulling on the two free ends. The loop maintains the tension without any knotting or crimping. Several sizes are available to cover a full range of patient sizes.
Author: R. Randy Basinger DVM, DACVS