Zlig ligament reconstruction versus tibial plateau leveling osteotomy for cranial cruciate ligament rupture in dogs: a prospective controlled study.

OBJECTIVES: Cranial cruciate ligament rupture (CCLR) is one of the most common causes of hindlimb lameness in dogs, causing stifle instability, osteoarthritis and damage to the medial meniscus. While tibial plateau leveling osteotomy (TPLO) is the most common performed method for cranial cruciate ligament rupture in dogs, intra-articular reconstruction of the cranial cruciate ligament is the gold standard in human medicine. The objective of this prospective clinical study was to investigate whether the synthetic ligament Zlig by Eickemeyer® for intra-articular reconstruction can achieve similar clinical and gait analysis results in cases of CCLR in dogs compared to TPLO. METHODS: Thirty dogs with CCLR were enrolled in this prospective clinical study at the small animal clinic at LMU Munich. The dogs underwent surgery with TPLO (n = 16) or the synthetic intra-articular ligament Zlig (n = 14) and were assessed preoperatively as well as 6, 12 and 18 weeks postoperatively. Clinical assessment included lameness scoring, joint effusion, pain response during clinical examination and tibial compression test. Objective gait analysis was performed using treadmill-based force plate and motion capture systems. RESULTS: Both groups showed significant clinical and functional improvement over the 18-week period. At 12 weeks, the TPLO group exhibited significantly greater reductions in lameness score, joint effusion and pain sensitivity of the stifle. At the all other time points, there were no significant differences between the TPLO group and the Zlig group. By week 18, all dogs treated with TPLO had a negative tibial compression test, while 78.6% (n = 11) of the dogs in the Zlig group were still tested positive. Total postoperative complication rate was 18.8% (n = 3) in the TPLO group and 35.7% (n = 5) in the Zlig group. CONCLUSION: Both surgical techniques resulted in improved limb function. The TPLO group showed more reliable stabilization and a lower complication rate in comparison to the Zlig group. The role of the residual instability in the dogs of the Zlig group needs further studies examining its biomechanical properties. Whether the intra-articular Zlig implant represents a potential alternative for the future needs to be further validated through more prospective studies over a longer time period.