Investigation of the effectiveness of the polyaxial klemp rod internal fixation method in distal femoral fractures: an experimental study in a sheep model

Aim: Main purpose of current research is; Investigation of effectiveness of Clamp-Rod Internal Fixation (CRIF) system developed by the Orthopaedic Development Institute (AO-VET) and the M-CRIF system developed by us with modification of the clamps and screws in the same system in terms of application and healing in an experimental supracondylar femoral fractures model in adult sheep. Material and Method: The study material consisted of 12 healthy sheep. The sheep with supracondylar fracture of the distal left femur were randomly divided into 2 groups. The first group (GI, n=6) was stabilized with the classic CRIF system, while the second group (GII, n=6) was stabilized with the M-CRIF system. The sheep were examined clinically, radiologically and biochemically before surgery, immediately after surgery and on days 3, 7, 14, 28, 45 and 60 to monitor bone healing. Results: The clinical gait score and the values of the pressure band analysis were higher in GII than in GI on days 28 and 45 (p<0.05). Bone alkaline phosphatase (B-ALP) on days 3, 14, 28, 45 and 60, collagen type I (COL1) on days 14, 28, 45 and 60, carboxy-terminal telopeptide (CTX) on day 45 were higher in GII than in GI (p < 0.05). Interleukin-10 (IL-10), one of the anti-inflammatory cytokines, was higher in GII than in GI on days 3, 28 and 45 (p <0.05). Radiographic results showed that bone healing was better in GII than in GI throughout the study. Conclusion: It was concluded that both the CRIF and M-CRIF systems can be used on an experimental model of supracondylar femoral fractures in sheep. However, the M-CRIF system is better suited to avoid complications such as implant-induced bone rotation and implant loosening, and these results should be supported by clinical studies. Key Words: Biomarkers, clamp-rod, distal femoral fractures, modified clamp-rod, sheep.