Equis ISSN 2398-2977

Calcaneal bursa: bursitis

Contributor(s): Jessica A Kidd-Millar, Graham Munroe

Introduction

  • Cause: direct trauma (sharp or blunt) and/or wounds in the region of the point of the hock, gastrocnemius tendon injuries   Gastrocnemius tendinitis  , osseous cyst-like lesions of the tuber calcanei   Bone: osseous cyst-like lesions  , tearing of the calcaneal insertions of the superficial digital flexor tendon (SDFT)   SDFT: tendinitis  , repetitive trauma.
  • Signs: lameness of variable degrees depending on etiology, variable distension of the intertendinous bursa +/- gastrocnemius bursa +/- subcutaneous bursa, generalized swelling +/- heat over the point of the hock (tuber calcanei), evidence of wound(s) in the region of the point of the tuber calcanei on the plantar aspect which may discharge fluid (synovial) or purulent exudate if open and draining.
  • Diagnosis: clinical signs, ultrasonography, centesis, radiography, bursoscopy.
  • Treatment: rest, intrabursal medications, systemic antibiotics and NSAIDs, bandaging, surgery.
  • Prognosis: guarded but dependent on etiology and presence of bone injury and sepsis.

Pathogenesis

Etiology

  • The calcaneal or intertendinous bursa lies between the dorsal surface of the SDFT and the gastrocnemius tendon. It extends from the proximal (~9.6 cm) to the distal (~7 cm) tuber calcanei on the plantar aspect of the calcaneus. In most horses there is a connection to the gastrocnemius bursa (100% medially; 50% laterally), which is small and located dorsal to the insertion of the gastrocnemius tendon on to the tuber calcanei. In 39% of horses in one study there was a connection to the variably present subcutaneous bursa slightly distal to the tuber calcanei.
  • Direct trauma (sharp or blunt) and/or wound(s) in the region of the tuber calcanei are the most common cause of inflammation and/or infection of the calcaneal bursa. Some of these are associated with osteolysis and/or fragmentation of the tuber calcanei. Many are sustained by the horse kicking a hard object or being kicked by another animal. Other structures in the anatomical region may be coincidentally damaged, including tendons of the SDFT and gastrocnemius, tarsocrural joint, tarsal sheath, and bones of the tarsus, including the sustentaculum tali.
  • Mild distension of the calcaneal bursa has been noted in gastrocnemius tandon injuries   Gastrocnemius tendinitis  .
  • Osseous cyst-like lesions of the tuber calcanei may also lead to mild calcaneal bursal distension if they open into the bursa   Bone: osseous cyst-like lesions  . These lesions were originally said to be associated with an entheseopathy of the gastrocnemius tendon but no lesions in the tendon of this muscle have been found. Trauma may be involved in some cases.
  • Tearing of the calcaneal insertions of the SDFT are associated with lameness and distension of the calcaneal bursa. Some of these cases will also have an unstable displacement of the SDFT from the calcaneus   SDFT: luxation  .
  • Distension of the subcutaneous bursa or development of an acquired bursa over the top of the tuber calcanei can occur due to repetitive trauma such as stable wall kicking or leaning backwards during travelling. There is usually no associated lameness. Sepsis of the bursa alone can occur following wounds at the tuber calcanei.
  • Mild distension has also been recorded as an incidental finding both uni- and bilaterally in non-lame horses.

Predisposing factors

General
  • Wound(s) at the tuber calcanei.

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from VetMedResource and PubMed.
  • Wright I M & Minshall G J (2012) Injuries of the calcaneal insertions of the SDFT in 19 horses. Equine Vet J 44 (2), 136-142 PubMed.
  • Post E M, Singer E R & Clegg P D (2007) An anatomic study of the calcaneal bursae in the horse. Vet Surg 36 (1), 3-9 PubMed.
  • Evelyn M, Singer E R, Clegg P D, Smith R K & Cripps P J (2003) Retrospective study of 24 cases of septic calcaneal bursitis in the horse. Equine Vet J 35 (7), 662-668 PubMed.
  • MacDonald M H, Honnas C M & Meagher D M (1989) Osteomyelitis of the calcaneus in horses. Vet Surg 27, 561-567 PubMed.

Other sources of information

  • Sisson S & Grossman J D (1974) Eds. The Anatomy of Domestic Animals. W B Saunders, USA. pp 364-370.


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