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
. - 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
- Sesamoiditis Sesamoid: disease.
- Bipartite or multipartite sesamoids Sesamoid: developmental malformation
. - Metacarpal/metatarsal fractures or dislocations.
- Phalangeal fractures or dislocations Greyhound: digit injuries.
- Osteoarthritis of metacarpo/metatarso-phalangeal joints Arthritis: osteoarthritis.
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.
- 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.