Synovial Fluid MMP-2 and MMP-9 Levels in Internal or External Fixation for Intra-Articular Fractures / Poziom MMP-2 i MMP-9 w mazi stawowej przy wewnętrznym i zewnętrznym zespoleniu po złamaniach wewnątrzstawowych

The purpose of this study was to evaluate whether internal fixation or external skeletal fixation (ESF) results in better “joint health” following traumatic injury to the stifle by assessing lameness and measuring matrix metalloproteinase MMP-2 and MMP-9. Dogs with skin grafts and transarticular ESFs were included in group A. Dogs with intra-articular fractures of the distal femur were randomly divided into groups B and C, and treated with either internal or ESF, respectively. Dogs in group D had diaphyseal tibial fractures treated with ESF. Synovial fluid samples were collected pre-operatively and again 7 days and 30 days postoperatively to measure MMP-2 and -9 levels via zymography. Preoperative MMP-9 levels were higher in groups B and C than A and D. Over time, MMP-2 levels increased in groups A-C, and MMP-9 levels significantly decreased in groups B and C by 30 days postoperatively. ESF appears superior to internal fixation for repair of intra-articular fractures of the distal femur, and MMP-2 and MMP-9 could serve as markers of either fracture healing or overall joint health, particularly in the setting of PTOA.