Meniscal translocation and deformation throughout the range of motion of the equine stifle joint: an in vitro cadaveric study.
Authors: Fowlie J G, Arnoczky S P, Stick J A, Pease A P
Journal: Equine veterinary journal
Summary
# Editorial Summary: Meniscal Translocation in the Equine Stifle Understanding why medial meniscal tears concentrate at the cranial horn requires knowledge of how these structures move and deform throughout the stifle's range of motion—information that Fowlie and colleagues obtained through radiographic and MRI imaging of cadaveric specimens, embedding radiopaque markers in menisci from six stifles and capturing movement at 15° intervals from full flexion (30°) to full extension (160°), whilst three additional stifles underwent MRI scanning to assess tissue strain. The lateral meniscus demonstrated substantially greater cranial-caudal translocation (1.6 times more movement) than the medial across the full flexion-extension arc, yet the cranial horn of the medial meniscus—normally the most immobile of the four horns—underwent significant cranial displacement and axial compressive strain specifically during the final 10° of extension. These biomechanical findings explain the clinical pattern of cranial horn medial meniscal injuries observed in equine practice: hyperextension creates a mechanical vulnerability at this precise location through cumulative strain and restricted mobility. For practitioners assessing stifle injuries or working with horses prone to hyperextension during athletic work, this research highlights why the cranial horn of the medial meniscus warrants particular attention, and may inform both preventative management and rehabilitation strategies targeting dynamic stifle stability.
Read the full abstract on PubMed
Practical Takeaways
- •Medial meniscal tears at the cranial horn may result from terminal stifle extension mechanics rather than flexion-based injuries—assess hyperextension patterns in lame horses
- •The reduced mobility of the medial meniscus cranial horn combined with high compression stress in extension suggests conditioning and training should avoid repetitive deep extension under load
- •Understanding that the lateral meniscus is significantly more mobile helps explain why medial-sided stifle pathology is more common clinically and warrants closer monitoring during post-injury rehabilitation
Key Findings
- •Lateral meniscus translocates 1.6 times more cranial-caudally than medial meniscus from full extension to full flexion (P = 0.002)
- •Cranial horn of medial meniscus is the least mobile of the four horns yet shows significant cranial displacement in the terminal 10° of extension
- •Greater axial compressive strain occurs in the cranial horn of the medial meniscus compared to lateral in terminal 10° of extension (P = 0.017)
- •Stifle hyperextension places the cranial horn of the medial meniscus at mechanical risk, potentially explaining the higher prevalence of tears at this location