18 Feb, 2025
The Concept: Reconstructing the Torn Ligament Itself
This approach does not involve treating laxity with a compensatory surgery but rather addressing the root problem by reconstructing the torn ligament itself. The goal is to restore stifle stability in all positions using a minimally invasive and low-trauma technique, allowing the animal to return to normal activity very quickly—once the wound has healed.
Why Use a Synthetic Implant?
Synthetic ligaments have been used in human surgery since 1992 (1).Osteotomy requires a bone consolidation phase, and autografts or allografts need a revascularization period, which takes time. In contrast, synthetic ligaments are strong from the outset. The Z-lig (STIF - Pet Care) was studied for seven years to precisely meet the biomechanical and biocompatibility needs of animals, ranging in size from 5 kg to over 81 kg. The strongest implant can withstand up to 6,000N of tension.
The Mechanical and Biological Advantages of Free Fibers
The Z-lig is an evolution of the free-fiber synthetic ligament used in human surgery. It is smaller but three times stronger, thanks to the new generation of fibers it is made of and its unique free-fiber architecture.
Placed inside the joint, these fibers are specifically designed to withstand simultaneous tension, flexion, and especially torsion forces. Unlike woven, braided, or knitted fibers, they do not cut into each other. Additionally, their highly porous structure allows fibroblasts to colonize this portion of the implant when a healthy ligament remnant is present.
A Minimally Invasive Method with Rapid Recovery
Several anatomical studies have shown the presence of an isometric point on the inner face of the external condyle (2), located at the center of the 140° arc formed by the posterior part of the external condyle. The developed surgical technique allows for placing the synthetic ligament in this isometric zone of the femur, limiting implant length variations during flexion and extension. This enables physiological reconstruction without altering the stifle joint’s architecture, requiring only four bone tunnels.
References:
(1) Kai Gao, M.D., Shiyi Chen, M.D., Ph.D., Lide Wang, M.D., Weiguo Zhang, M.D., Yifan Kang, M.D., Qirong Dong, M.D., Haibin Zhou, M.D., and Linan Li, M.D. Anterior Cruciate Ligament Reconstruction With LARS Artificial Ligament: A Multicenter Study With 3- to 5-Year Follow-up. The Journal of Arthroscopic and Related Surgery, Vol 26, No 4 (April 2010): pp 515-523.
(2) Cazenave A, Laboureau J.P. (1990) Isometric Reconstruction of the Anterior Cruciate Ligament. Pre- and Perioperative Determination of the Femoral Point (Rev. Chir. Orthop. Vol 76:288-292).
Additional scientific resources are available at www.stif-petcare.com.
