Ultrasonography of the stifle

Stifle injuries are increasingly recognised as a major cause of hind limb lameness and commonly affect the soft tissues of the joint in adult horses, making ultrasonography a vital part of diagnostic imaging of this joint. This article aims to provide an introduction to stifle ultrasonography. To ensure comprehensive evaluation of the stifle, a systematic approach is necessary. The ultrasonographic examination is divided into five approaches: initially weight-bearing scans should be obtained of the cranial aspect (for the femoropatellar joint), medial aspect (for the medial femorotibial joint), and lateral aspect (for the lateral femorotibial joint), followed by flexed views from cranial (for the cranial aspect of the femorotibial joints) and, finally, in limited cases because pathology is rarer and the technique more demanding, weight-bearing views of the caudal aspect (for the caudal parts of both femorotibial joints). For the femoropatellar joint, ultrasound can be used to identify bruising (haematoma), injuries to the patellar ligaments, trochlear ridges (including osteochondrosis), and patella and tibial crest fractures. For the femorotibial joints, injuries to the menisci are the most common, but ultrasound can also identify rarer collateral and cruciate ligament injuries. and abnormalities of the weight-bearing surfaces of the femoral condyles, such as cartilage damage and subchondral bone cysts

Changes in concentrations of haemostatic and inflammatory biomarkers in synovial fluid after intra-articular injection of lipopolysaccharide in horses

Abstract Background Septic arthritis is a common and potentially devastating disease characterized by severe intra-articular (IA) inflammation and fibrin deposition. Research into equine joint pathologies has focused on inflammation, but recent research in humans suggests that both haemostatic and inflammatory pathways are activated in the joint compartment in arthritic conditions. The aim of this study was to characterize the IA haemostatic and inflammatory responses in horses with experimental lipopolysaccharide (LPS)-induced joint inflammation. Inflammation was induced by IA injection of LPS into one antebrachiocarpal joint of six horses. Horses were evaluated clinically with subjective grading of lameness, and blood and synovial fluid (SF) samples were collected at post injection hours (PIH) -120, −96, −24, 0, 2, 4, 8, 16, 24, 36, 48, 72 and 144. Total protein (TP), white blood cell counts (WBC), serum amyloid A (SAA), haptoglobin, iron, fibrinogen, thrombin-antithrombin (TAT) and d-dimer concentrations were assessed in blood and SF. Results Intra-articular injection of LPS caused local and systemic signs of inflammation including increased rectal temperature, lameness and increased joint circumference and skin temperature. Most of the biomarkers (TP, WBC, haptoglobin, fibrinogen and TAT) measured in SF increased quickly after LPS injection (at PIH 2–4), whereas SAA and d-dimer levels increased more slowly (at PIH 16 and 144, respectively). SF iron concentrations did not change statistically significantly. Blood WBC, SAA, haptoglobin and fibrinogen increased and iron decreased significantly in response to the IA LPS injection, while TAT and d-dimer concentrations did not change. Repeated pre-injection arthrocenteses caused significant changes in SF concentrations of TP, WBC and haptoglobin. Conclusion Similar to inflammatory joint disease in humans, joint inflammation in horses was accompanied by an IA haemostatic response with changes in fibrinogen, TAT and d-dimer concentrations. Inflammatory and haemostatic responses were induced simultaneously and may likely interact. Further studies of interactions between the two responses are needed for a better understanding of pathogenesis of joint disease in horses. Knowledge of effects of repeated arthrocenteses on levels of SF biomarkers may be of value when markers are used for diagnostic purposes