Contributors: Michael Guilliard

 Species: Canine   |   Classification: Diseases

Introduction Pathogenesis Diagnosis Treatment Outcomes Further Reading

Introduction

  • Cause: trauma.
  • Signs: acute onset lameness with soft tissue swelling and pain around sesamoid bones.
  • Reduced range of movement of metacarpo/metatarso-phalangeal joints.
  • Pain and crepitus on flexion and extension of the affected joint.
  • Diagnosis: history, signs, radiography.
  • Treatment: conservative support dressings adequate for pet dog; surgical removal of fractured sesamoid is usual in sporting dogs.
  • Prognosis: good.

Presenting Signs

  • Acute lameness, pain and swelling localized to manus/pes.

Pathogenesis

Etiology

  • Sesamoid bone fractures due to direct trauma or mechanical overload.

Pathophysiology

  • Acute trauma.
  • Configuration may be slab, mid-body, sagittal or chip fractures.
  • Sesamoid bones 2 and 7 more prone to injury as the flexor tendons lie centrally between the paired sesamoid bones in digits 3 and 4 but are offset in digits 2 and 5 to exert more pressure on sesamoids 2 and 7.

Diagnosis

Presenting Problems

Client History

  • Lameness.
  • Acute, severe joint pain and swelling.

Clinical Signs

  • Acute, severe pain and swelling of the area surrounding the sesamoid bone.
  • Focal pain is present for several weeks.
  • Crepitus and pain on manipulation of the affected metacarpo/metatarso-phalangeal joint.
  • Radiographs confirm diagnosis.

Diagnostic Investigation


Radiography
  • See radiography of the manus Radiography: carpus and forefoot or pes Radiography: tarsus and hindfoot.
  • Radiographs reveal a sharp fracture line definition Foot: sesamoid fracture - radiograph Foot: sesamoid fracture - radiograph DPa.
  • Fragments are often only minimally displaced as sesamoid is confined in the interosseous muscle tendon of insertion.
  • Radiographs of both limbs are useful for highlighting subtle lesions.

Differential Diagnosis

Treatment

Initial Symptomatic Treatment

Pet dogs can be treated conservatively with non-steroidal anti-inflammatory treatment Analgesia: NSAID and rest. Support dressings are not indicated.

  • Racing/sporting dogs may require surgical removal of the fractured sesamoid bone Greyhound: digit injuries :
    • Surgery involves direct incision over affected sesamoid bone, avoiding metacarpal pad.
    • Locate superficial digital flexor tendon and incise annular ligament on affected side.
    • Retract annular ligament and remove either the fragment or the entire sesamoid by sharp dissection.
    • Flush area, suture annular ligament, subcutaneous tissue and skin.
  • Support dressing for 1 week, restrict to lead exercise for 2 weeks before gradually return to normal exercise.

Subsequent Management

Monitoring


Conservative management
  • Restrict to lead exercise for 4 weeks.
  • Monitor pain response to direct palpation of sesamoid and pain on flexion and extension of metacarpo/metatarso-phalangeal joint.
    The clinical response is the most important feature.
  • Bone union is rarely achieved due to distractive forces on the bone fragments, but lameness generally resolves.
Surgical management
  • Bandage for 1 week, rest for a further week then allow restricted exercise until completely pain-free.

Outcomes

Prognosis

  • Good.

Expected Response to Treatment

  • Monitor lameness and pain response to palpation of the affected sesamoid bone and flexion and extension of the affected metacarpo-phalangeal joint.

Reasons for Treatment Failure

  • Lameness still present after 6 weeks of conservative management → proceed to surgical excision.
  • Chronic cases may remain lame even after surgical resection due to degenerative osteoarthritis of the metacarpo/metatarso-phalangeal joint.

Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Davis P E et al (1969) Fractures of the seasmoid bones in the greyhound. Aust Vet J 45 (1), 15-9 PubMed.
  • Bateman J K et al (1959) Fractured sesamoids in the greyhound. Vet Rec 71, 101.

Other sources of information

  • Robins G M & Read R A (1998)diseases of the sesamoid bones.In:Canine Sports Medicine and Surgery.Bloomberg M S, Dee J F & Taylor R A (eds). W B Saunders Company, Philadelphia, pp 255-264.
  • Eaton-Wells R (1994)The digits.In:Manual of small animal arthrology.Chapter 14 pp 237. BSAVA.
  • Robins G M & Read R A (1993)diseases of the sesamoid bones.In:Disease mechanisms in small animal surgery.2nd edn. pp 1094.

Other Sources of Information