Ultrasonographic appearance of normal and injured lateral patellar ligaments in the equine stifle.
Authors: Gottlieb R, Whitcomb M B, Vaughan B, Galuppo L D, Spriet M
Journal: Equine veterinary journal
Summary
# Editorial Summary: Ultrasonographic Assessment of Lateral Patellar Ligament Injuries in Horses Understanding the normal ultrasonographic anatomy of the equine lateral patellar ligament (LPL) is essential for accurate diagnosis, yet detailed reference data has been lacking until this 2016 investigation by Gottlieb and colleagues. The researchers mapped the normal appearance of the LPL across twelve sound horses, documenting how the ligament transitions from ill-defined margins at the patella through a flattened, bilobed configuration over the lateral trochlear ridge to a tapered, striated structure at the tibial insertion—a progression that clinicians must recognise to avoid misinterpreting normal anatomy as pathology. Retrospective analysis of eighteen horses with LPL injuries revealed a predominantly traumatic origin: all cases were acute, twelve presented with visible wounds, and radiography identified associated fractures in eleven horses involving the tibial tuberosity, patella, or lateral trochlear ridge; 78% of these injuries presented as severe ultrasonographic lesions with the mid to insertional region most commonly affected, and severe lameness (grades 4–5/5) was evident in eleven animals. Prognosis was variable but generally guarded, with nine horses returning to ridden work, though three required euthanasia due to concurrent injuries and five developed secondary osteomyelitis or synovial sepsis. This work underscores that LPL injuries typically result from significant craniolateral stifle trauma rather than overuse, and careful baseline understanding of normal ligament anatomy is critical for farriers, vets and rehabilitation specialists involved in diagnosing stifle pathology.
Read the full abstract on PubMed
Practical Takeaways
- •Understanding normal LPL ultrasound anatomy across its length is critical to avoid false positive diagnoses—morphology changes significantly from patella to tibia
- •LPL injuries typically present as acute, severe cases with concurrent fractures and high lameness grades; ultrasonographic follow-up showed minimal healing changes over time
- •Prognosis depends heavily on concurrent injuries and complications (osteomyelitis, synovial sepsis); isolated LPL injuries without fractures had better outcomes than those with skeletal involvement
Key Findings
- •Normal LPL shows progressive changes from origin to insertion: ill-defined margins at patella, flattened bilobed appearance over lateral trochlear ridge, and tapered striations at tibial insertion
- •LPL injuries occurred in 18 horses with 78% showing severe ultrasonographic lesions; mid to insertional portion affected most frequently
- •All 18 LPL injuries were acute with 12 cases presenting with wounds; 11 horses were severely lame (grade 4-5/5)
- •Radiographic fractures involved LPL attachments in 9 of 18 injured horses; 9 horses returned to riding but 3 required euthanasia due to concurrent injuries