Sesamoid: disease

• Cause: chronic inflammation of the sesamoid bones.
• Cause of lameness and incidental finding in the racing greyhound.
• Lameness in large pet breeds, eg Rottweiler.
• Signs: often an insidious onset, progressive forelimb lameness in young dogs, or can also be acute onset lameness in adults.
• Diagnosis: clinical signs and radiography.
• Treatment: conservative, or surgical removal of sesamoids.
• Prognosis: guarded for resolution.

• Lameness (usually in the forelimbs) Lameness: general - investigation Lameness: forelimb - investigation.
• Pain on flexion of metacarpo-phalangeal joints.
• Reduced range of motion.
• Joint swelling/effusion in acute stage; fibrosis and degenerative joint disease in later stage.

• Young growing dogs (3-4 months) but may present at any age.

• Large breed, eg Rottweiler Rottweiler.
• Racing Greyhounds Greyhound.

• Often require chronic conservative management.

• Lytic lesions possible manifestation of osteochondrosis Osteochondrosis.
• Inflammatory changes seen with enthesiophyte formation, possible traumatic etiology.
• Degenerative secondary changes may be present in the metacarpo-phalangeal joint.

• Fragmentation of the sesamoid bone may be result of abnormal endochondral ossification, ie a manifestation of osteochondrosis.
• Multiple exostoses within the soft tissue attachments of the sesamoid may have a traumatic etiology.
• There may be calcification around the sesamoid bones or osteophytosis around the metacarpo-phalangeal joint.
• These changes may be secondary to joint trauma or instability.
• Repeated stress on palmar surface of sesamoids by digital flexor tendons during hyperextension of metacarpo-phalangeal joints may → fatigue fractures and degeneration of the underlying bone and soft tissues.
• Digits 2 and 5: flexor tendon pressure solely on inner sesamoids 2 and 7.
• Digits 2 and 5: metacarpal bones are asymmetrical so axial condyle bears more load.
• Histologically see bone fracture and necrosis supporting vascular compromise theory.

• Slow, progressive lameness seen over weeks to months in the young dog.

• Pain and soft tissue swelling around joint.

• Lameness (usually forelimb).
• Joint swelling.

• Localized soft tissue swelling around affected palmar aspect of the metacarpo-phalangeal joint.
• Pain on metacarpophalangeal joint flexion.
• Reduced range of flexion.

• Dorsopalmar radiographs of manus Radiography: carpus and forefoot   :
  • Lysis of affected sesamoid.
  • Multiple calcified masses replacing sesamoid.
  • In some cases, calcification around sesamoid bones and metacarpo-phalangeal joint osteophytosis.

• Sesamoid fractures Sesamoid: fracture.
• Bipartite or multipartite sesamoid bones (developmental malformation) Sesamoid: developmental malformation.
• Metacarpo-phalangeal joint dislocation/ligament damage Greyhound: digit injuries.
• Septic arthritis or cellulitis Arthritis: septic.
• Neoplasia of bone or soft tissue Bone: neoplasia.
• Hypertrophic osteodystrophy Hypertrophic osteopathy.
• LAMENESS ELSEWHERE! Rottweilers are prone to elbow and shoulder lameness.

• Acute stage:
  • Restricted exercise, with or without non-steroidal anti-inflammatory treatment Analgesia: NSAID for 4-8 weeks is often successful.
  • Pentosan polysulfate sodium Pentosan polysulfate recommended during the period of inactivity.
• Surgical excision is a possible treatment for chronic sesamoiditis not responding to conservative management.
  Surgical treatment carries a similar prognosis to conservative management and may not be beneficial.

• Conservative management, by monitoring lameness and pain on direct palpation of sesamoid bones and by manipulation of MCP joint.
• If still lame after 12 weeks rest, consider surgical excision of affected sesamoid bone and associated calcified bodies.

Treatment

• Unresolved lameness will require restricted exercise and pain management Pain: management.
• Surgical cases require of 1 week of bandage support post-surgery; then 3 weeks of lead exercise before returning to normal exercise if sound.

• Conservative treatment usually adequate for pet dog.
• If significant degenerative joint disease, may need long-term non-steroidal anti-inflammatory treatment or digit amputation for sporting dogs Amputation: digit Greyhound: digit injuries.
  Check for lameness elsewhere.

• Lameness should improve over 4-6 weeks in conservatively managed cases.
• If lameness persists after surgery, this may be due to degenerative changes at the MCP joint.

Refereed papers

• Recent references from PubMed and VetMedResource.
• Harasen G (2009) Sesamoid disease. Can Vet J 50 (10), 1095 PubMed.
• Daniel A, Read R A & Cake M A (2008) Vascular foramina of the metacarpophalangeal sesamoid bones of Greyhounds and their relationship to sesamoid disease. Am J Vet Res 69 (6), 716-721 PubMed.
• Matthews K G, Koblick P D, Whitehair J G & Bradley C (2001) Fragmented palmar metacarpo-phalangeal sesamoids in dogs: a long-term evaluation. Vet Comp Ortho Traumatol 14 (1), 7-14 UCDavis.
• Vaughan L C & France C (1986) Abnormalities of the volar and plantar sesamoid bones in Rottweilers. JSAP 27 (9), 551-8 VetMedResource.
• Bennett D & Kelly D F (1985) Sesamoid disease as a cause of lameness in young dogs. JSAP 26 (10), 567-79 VetMedResource.
• Bateman J K (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.
• Robins G M & Read R A (1993)diseases of the sesamoid bones.In:Disease mechanisms in small animal surgery.2nd edn. pp 1094.