Osteochondritis dissecans

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Osteochondritis dissecans (OCD) is a degenerative inflammatory disease of canine articular cartilage and subchondral bone and a leading cause of hip dysplasia and elbow dysplasia.

OCD results from avascular necrosis of subchondral bone, leading to articular erosion.

Although the humeral condyle (shoulder) is primarily predisposed, it has also been reported to affect the sacrum[1], distal femur[2] and tarsocrural joint[3][4]. Hindlimb involvement may progress to hip dysplasia.

A predisposition is observed commonly in large-breed dogs but small-breed dogs may also be affected[5].

The disease is often exacerbated clinically with high exercise activity. An underlying osteochondrosis appears to play a role in the pathogenesis of this disease. Chronic inflammation associated with this disease may predispose to osteosarcoma, although this has been rarely reported[6].

The onset of disease occurs between 5 months and 10 months of age in a large majority of cases, with males affected three times more frequently than females[7]. In approximately 50% of the cases, animals are affected bilaterally (as determined radiographically), although clinical signs of pain and lameness may occur only unilaterally.

OCD may also develop with a calcium-rich diet. Growing giant-breed dogs fed high-calcium diets (>3% of dry matter as calcium) experience greater development of osteochondrosis than control dogs. Even when dietary phosphorus is adjusted to maintain a physiologic calcium:phosphorus ratio, osteochondrosis can still occur[8].

Affected young dogs often present with mild intermittent lameness, with lameness score directly related to osteophyte size[9].

While a presumptive diagnosis may be made upon assessment of breed and clinical examination (palpation of the shoulder is generally nonrewarding), radiography is necessary for definitive diagnosis[10].

Radiographic findings include irregular radiolucent subchondral defects, usually involving the caudal aspect of the humeral head as well as subchondral sclerosis, calcified linear cartilage flaps, joint exophytes and osteoarthritis[11]. Lesions are usually localized to the central portion of the caudal aspect of the humeral head, at the approximate junction of the caudal and middle thirds of the articular surface[12].

Arthroscopy usually reveals the joint surface having a distinct pattern of centripetally oriented split-lines centrally[13].

A differential diagnosis would include osteochondrosis, osteomyelitis, ununited anconeal process, fragmented coronoid process, panosteitis and hypertrophic osteodystrophy.

Treatment for young dogs is best achieved with corrective surgery[14]. Surgery is indicated in dogs with persistent lameness that are unresponsive to rest and NSAIDS.

Supportive use of carprofen or meloxicam is recommended for palliative control of pain.

References

  1. Michal U et al (2004) Sacral osteochondrosis dissecans in a Bernese Mountain Dog: diagnosis and treatment. Schweiz Arch Tierheilkd 146(5):233-238
  2. Kulendra E et al (2008) Osteochondritis dissecans-like lesion of the intercondylar fossa of the femur in a dog. Vet Comp Orthop Traumatol 21(2):152-155
  3. Gielen I et al (2005) Computerized tomography compared with radiography in the diagnosis of lateral trochlear ridge talar osteochondritis dissecans in dogs. Vet Comp Orthop Traumatol 18(2):77-82
  4. Gielen I et al (2007) Comparison of subchondral lesion size between clinical and non-clinical medial trochlear ridge talar osteochondritis dissecans in dogs. Vet Comp Orthop Traumatol 20(1):8-11
  5. Bruggeman M et al (2010) Osteochondritis dissecans of the humeral head in two small-breed dogs. Vet Rec 166(5):139-141
  6. Holmberg BJ et al (2004) Osteosarcoma of the humeral head associated with osteochondritis dissecans in a dog. J Am Anim Hosp Assoc 40(3):246-249
  7. Harrison JW & Hohn RB (1975) Osteochondritis dissecans. In Bojrab MJ (ed): Current Techniques in Small Animal Surgery, vol 1. Philadelphia, Lea & Febiger
  8. Hazewinkel HW et al (1985) Influences of chronic calcium excess on the skeletal development of growing Great Danes. JAAHA 11:377-391
  9. van der Peijl GJ et al (2012) Osteochondrosis dissecans of the tarsus in Labrador Retrievers: clinical signs, radiological data and force plate gait evaluation after surgical treatment. Vet Comp Orthop Traumatol 25(2):126-134
  10. Chanoit G et al (2010) Comparison of five radiographic views for assessment of the medial aspect of the humeral condyle in dogs with osteochondritis dissecans. Am J Vet Res 71(7):780-783
  11. Olivieri M et al (2007) Arthroscopic treatment of osteochondritis dissecans of the shoulder in 126 dogs. Vet Comp Orthop Traumatol 20(1):65-69
  12. Craig PH & Riser WH (1965) Osteochondritis dissecans in the proximal humerus of the dog. J Am Vet Radiol Soc 6:40
  13. Zeissler M et al (2010) Cartilage thickness and split-line pattern at the canine humeral trochlea. Vet Comp Orthop Traumatol 23(5):343-347
  14. Biezyński J et al (2012) Assessment of treatment of Osteochondrosis dissecans (OCD) of shoulder joint in dogs - the results of two years of experience. Pol J Vet Sci 15(2):285-290