Clinical study evaluating the accuracy of injecting the distal tarsal joints in the horse.
Authors: Seabaugh K A, Selberg K T, Mueller P O E, Eggleston R B, Peroni J F, Claunch K M, Markwell H J, Baxter G M
Journal: Equine veterinary journal
Summary
# Editorial Summary: Accuracy of Distal Tarsal Joint Injections in Horses Intra-articular injections of the distal tarsal joints are routine diagnostic and therapeutic procedures in equine practice, yet their success rates have never been rigorously quantified. This 2017 study by Seabaugh and colleagues assessed injection accuracy by having six experienced equine surgeons and residents inject contrast-medium solutions into the centrodistal (CD) and tarsometatarsal (TMT) joints of sedated horses, with radiographic verification of needle placement. Results revealed a stark disparity in technical difficulty: the TMT joint was successfully injected in 96% of attempts (23/24), whereas the CD joint achieved only 42% accuracy (10/24), with failed injections typically depositing contrast into periarticular tissues rather than the joint capsule. Notably, radiographic examination demonstrated communication between the two joints in approximately a quarter of cases, suggesting that some therapeutic benefit may occur even with initially misplaced needles. The authors were unable to standardise injection technique across operators, which may partly explain the high CD joint failure rate and should prompt practitioners to utilise radiographic or ultrasound guidance when injecting the CD joint specifically, rather than relying on landmark-based techniques alone.
Read the full abstract on PubMed
Practical Takeaways
- •TMT joint injections are reliable and can be performed with high confidence in sedated horses, but CD joint injections frequently miss the target and require verification via radiography before assuming success
- •When injecting the CD joint, use imaging guidance (radiographs) to confirm needle placement in the joint space rather than periarticular tissues, as blind injection has only 42% accuracy
- •Be aware that successful TMT injections may distribute medication to the CD joint via communication in 26% of cases, which could affect diagnostic anaesthesia interpretation
Key Findings
- •Tarsometatarsal joint injection accuracy was 96% (23/24 joints) across six operators
- •Centrodistal joint injection accuracy was only 42% (10/24 joints), with contrast medium frequently placed in periarticular tissues
- •Communication between TMT and CD joints was visible in 26% of successful TMT injections
- •Injection technique could not be standardised across operators despite specific requests