Serum amyloid A and fibrinogen as markers for early detection of surgical site infection associated with internal fixation in the horse.

The objective of this study was to determine the diagnostic ability of serum amyloid A (SAA) and fibrinogen for early detection of surgical site infection (SSI) after equine internal fixation. Horses undergoing internal fixation for fracture, arthrodesis, or osteotomy with internal fixation for limb deformity were included in the study. SAA and fibrinogen were measured on blood samples preoperatively and on days 1, 3, 5, 7, 10, and 14 postoperatively. Statistical analysis included use of Spearman's rank correlation, logistic regression, and calculating the area under the receiver operating characteristic (ROC) curve. SAA and fibrinogen measurements were both associated with SSI, with SAA being considered an excellent marker (area under the ROC curve 0.8) and fibrinogen being considered acceptable (<0.8). As the amount of time postoperatively increased, SAA elevations indicated a higher likelihood of SSI (area under the ROC curve 0.8 compared with fibrinogen 0.7). SAA and fibrinogen were predictive markers of SSI and SAA is of greater diagnostic utility when compared with fibrinogen. Persistent elevations of SAA postoperatively are associated with the development of SSI. Serial monitoring of SAA can be used to help predict the development of SSI in horses undergoing internal fixation. This may lead to earlier suspicion, and therefore recognition and treatment of SSI.

Autologous Platelet Lysate Does Not Enhance Chondrogenic Differentiation of Equine Bone Marrow-Derived Mesenchymal Stromal Cells Despite Increased TGF-ß1 Concentration.

Bone marrow-derived mesenchymal stromal cells (BM-MSCs) are being investigated for their potential in the treatment of musculoskeletal injuries, including tendon and ligament lesions, and cartilage lesions. Culture expansion of cells has traditionally been performed in medium supplemented with fetal bovine serum (FBS), however, concerns regarding the antigenicity and potential viral or prion contamination of FBS have prompted interest in alternative medium supplements. Platelet lysate (PL) contains elevated concentrations of growth factors, including transforming growth factor-ß (TGF-ß), platelet-derived growth factors, and fibroblast growth factor, released from the α-granules of platelets; therefore, PL could be an ideal medium supplement. The effect of PL on mesenchymal stromal cell (MSC) growth and differentiation has not been fully elucidated. We hypothesized that PL medium would contain significantly higher amounts of TGF-ß1 than FBS medium and would be associated with enhanced osteogenic and chondrogenic differentiation. MSCs were isolated from bone marrow collected from five adult horses. Cells were cultured in traditional medium supplemented with FBS or in medium supplemented with fibrinogen depleted-PL (FD-PL). Immunophenotyping was performed using flow cytometry. Trilineage differentiation was assessed through histology and gene expression analysis using quantitative reverse transcription-polymerase chain reaction. TGF-ß1 was quantified in both medium types. The immunophenotypes of BM-MSCs cultured in FBS and FD-PL medium were similar with both culture types containing cells positive for stromal cell markers [cluster of differentiation 29 (CD29), CD44, CD90, CD105, and major histocompatibility complex I (MHCI)] and negative for exclusion markers (CD45, CD79α, and MHCII). Despite significantly higher TGF-ß1 concentration in FD-PL medium, chondrogenic and osteogenic differentiation were not significantly different between FBS and FD-PL supplemented cultures. PL is an appropriate alternative medium supplement for the culture of equine BM-MSCs up to passage 3. However, despite increased TGF-ß1 concentration in FD-PL medium, significant changes in chondrogenic differentiation compared with FBS medium should not be expected.

Arthrodesis of the metacarpophalangeal and metatarsophalangeal joints to treat osteoarthritis in 17 horses.

OBJECTIVE: To describe arthrodesis of the metacarpophalangeal (MCP) or metatarsophalangeal (MTP) joint with a locking compression plate (LCP) and a metallic tension band and report the outcome of horses treated for osteoarthritis (OA) with this technique. STUDY DESIGN: Retrospective case series. ANIMALS: Seventeen horses with OA of the MCP or MTP joint treated with arthrodesis. METHODS: Medical records (2004-2017) of horses treated for OA with arthrodesis of the MCP or MTP joint with an LCP and metallic tension band were reviewed. Preoperative variables included age, sex, breed, affected limb, and lameness grade. Surgical variables included implants used, surgery time, postoperative angle of joint, intraoperative complications, and anesthetic recovery method. Outcome was obtained from medical records and phone interviews. RESULTS: Lameness was scored as 4 out of 5 (range, 2-4) in 13 of 17 horses. All horses survived to discharge and were alive >6 months postoperatively, without any report of long-term complications. All horses were allowed unrestricted turnout, and 1 horse was lightly ridden. No postoperative infections or implant failures were reported. The only complications consisted of cast sores (n = 4). CONCLUSION: Arthrodesis of the MCP/MTP joint was associated with acceptable morbidity and good long-term outcomes in these 17 horses with OA refractory to medical management. CLINICAL SIGNIFICANCE: The morbidity and prognosis after fetlock arthrodesis for OA seem more favorable than reported in horses treated with traumatic disruption of the suspensory apparatus.