Osteoarthritis of the talocalcaneal joint in 18 horses.
Authors: Smith R K W, Dyson S J, Schramme M C, Head M J, Payne R J, Platt D, Walmsley J
Journal: Equine veterinary journal
Summary
# Editorial Summary: Osteoarthritis of the Talocalcaneal Joint in 18 Horses Talocalcaneal osteoarthritis remains a diagnostic challenge in equine practice, presenting as moderate to severe hindlimb lameness of sudden onset in mature sports horses (typically aged 7–16 years) with minimal localising clinical signs beyond exacerbation on hock flexion. This retrospective review of 18 cases from four referral centres established that whilst tarsocrural joint analgesia improved lameness in only 55% of cases tested, perineural analgesia of the tibial and fibular nerves produced complete soundness in 43% and substantial improvement in a further 50%, suggesting the condition's variable presentation and diagnostic difficulty. Radiographic examination revealed characteristic subchondral bone lysis, sclerosis and irregular joint space width (best visualised on lateromedial views), whilst nuclear scintigraphy in seven horses demonstrated marked plantaromedial uptake around the talus, supporting the diagnosis when clinical findings remained inconclusive. Conservative management—including box or pasture rest and intra-articular medication with corticosteroids, hyaluronic acid or polysulphated glycosaminoglycans—proved uniformly unsuccessful with all treated horses remaining lame; of 10 horses managed conservatively alone, six were euthanased, three retired and one remained lame in light work. Surgical arthrodesis using obliquely-placed AO screws across the talocalcaneal joint from the plantarolateral aspect resulted in improved lameness in all six cases treated, making this the treatment of choice despite the guarded prognosis for complete return to soundness, whilst other surgical approaches (neurectomy and subchondral forage) failed to resolve lameness in the two horses attempted
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Practical Takeaways
- •Consider talocalcaneal osteoarthritis in cases of acute hindlimb lameness with inconsistent diagnostic analgesia results and hock flexion-induced pain, as clinical signs are non-specific and easily missed.
- •Conservative treatment including intra-articular medications is largely ineffective for this condition; early referral for surgical arthrodesis should be considered rather than prolonged conservative management.
- •Nuclear scintigraphy showing uptake plantaromedially in the talus region and lateromedial radiographic views demonstrating subchondral changes support the diagnosis when clinical findings are ambiguous.
Key Findings
- •Talocalcaneal osteoarthritis caused acute-onset moderate to severe lameness in 18 horses aged 7-16 years with few localizing clinical signs beyond worsening with hock flexion.
- •Diagnostic analgesia (tarsocrural joint analgesia and perineural nerve blocks) provided inconsistent results, with only 55% and 43% improvement respectively, making diagnosis challenging.
- •Conservative management including intra-articular corticosteroids, hyaluronic acid, and polysulphated glycosaminoglycan failed in all 14 horses treated, with 6 euthanized and 3 retired.
- •Surgical arthrodesis of the talocalcaneal joint using 2-3 oblique 5.5 mm AO screws resulted in lameness improvement in all 6 treated horses, offering superior outcomes compared to conservative management.