1 year-old, Male, Spaniel

History:  Chronic significant lameness for several weeks of the left front leg, today grade 3/5. Painful with extension and manipulation of the elbow.

Imaging:  Non-contrast enhanced elbow CT (1 mm in high frequency/bone algorithm)

  

 

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 Conclusions:

This is a classic example of bilateral incomplete ossification of the humeral condyle (IOHC). There are similar left and right humeral condylar lesions characterized by undulant sagittal plane hypoattenuating defects centered on midline surrounded by moderate subchondral sclerosis (hyperattenuating subchondral bone). On the left there is mild widening of this defect compared to the right (dorsal plane reconstruction). Bilaterally there is no evidence of a step defect associated with the medial and lateral components of the cortices to indicate a displaced fracture.

IOHC is thought to result from failure of the medial and lateral aspect of the humeral condyle to unite.  However, it is important to realize that a fissure can develop in a humeral condyle that has undergone complete fusion; i.e. acquired IOHC (Farrell, 2011).

IOHC will predispose to an intercondylar “Y” fracture of the distal humerus

Spaniels are overrepresented for IOHC and, as such, IOHC should always be considered in Spaniels with chronic forelimb lameness. However, other breeds (such as Shepherds, Labradors and large breed dogs in particular) and also other species (Vietnamese pot-bellied pigs) can be affected.

Diagnosing IOHC with radiographs can be inaccurate due to superimposition of the cleavage plane in the humeral condyle on the olecranon in craniocaudal radiographs.  Slight elbow obliquity for the craniocaudal view may enhance the conspicuity of the cleavage plane.  CT is the test of choice for diagnosis of IOHC.  The use of MRI for diagnosis of IOHC has yet to be thoroughly investigated. This disease can often be bilateral even if lameness is unilateral, so imaging both limbs is recommended if this disease is suspected.

Additionally, in this dog there is bilateral medial coronoid disease with moderate sclerosis of the medial coronoid process of the left and right ulna with osteophyte formation on the cranial aspect of each medial coronoid process. There is no evidence of fragmentation or a fracture of either coronoid process.  Medial coronoid disease has been reported in 26% of patients with IOHC and degenerative joint disease was found in 79% of elbows in one study (Carrera et al., 2008).

References: 

Carrera I, Hammond GJ, Sullivan M. Computed tomographic features of incomplete ossification of the canine humeral condyle. Vet Surg. 2008;37:226–231.

Farrell M.  Progression of humeral intercondylar fissure in a Cocker Spaniel.  Vet Surg. 2011; 40:966-971.

Marcellin‐Little DJ, DeYoung DJ, Ferris KK, Berry CM. Incomplete ossification of the humeral condyle in spaniels. Vet Surg. 1994;23:475–487.

Martin RB, Crews L, Saveraid T, Conzemius MG. Prevalence of incomplete ossification of the humeral condyle in the limb opposite humeral condylar fracture: 14 dogs. Vet Comp Orthop Traumatol. 2010;23:168–172.

Moores AP, Agthe P, Schaafsma IA. Prevalence of incomplete ossification of the humeral condyle and other abnormalities of the elbow in English  Springer Spaniels. Vet Comp Orthop Traumatol. 2012;25:211–216.

Samii VF, Hornof WJ. Incomplete ossification of the humeral condyle in Vietnamese pot-bellied pigs. Vet Radiol Ultrasound. 2000 Mar-Apr;41(2):147-53.

Wisner and Zwingenberger. Atlas of Small Animal CT and MRI. Wiley Blackwell 2015.

2 comments

  1. Yet another interesting case! Here is my interpretation:

    FINDINGS:
    – The medial condyles of the ulnae are bilaterally irregularly shaped, thickened, and heterogeneous in mineral attenuation (left worse than right). This is further characterized by decreased mineral attenuation of the tip of the medial coronoid processes and increased mineral attenuation of the trabecular bone.
    – Surrounding the left and right cubital joint, moderate osteophyte/enthesophyte formation is present, particularly along the medial and lateral coronoid processes of the ulnae, humeral epicondyles, and humeral condyles, bilaterally (left worse than right).
    – The radial incisures are bilaterally irregular (left worse than right).
    – Bilaterally traversing the supratrochlear foramina through the mid aspect of the humeral condyles, between the trochlea and capitulum, there is a well-defined, irregularly marginated, minimally displaced fissure with moderate to severe surrounding sclerosis.
    – The soft tissues of the cubital joints are incompletely evaluated.

    CONCLUSIONS:
    Bilateral medial coronoid disease, incomplete ossification of the humeral condyles, with moderate osteoarthrosis (left worse than right). Given the clinical history, the medial coronoid disease is likely attributable to the patient’s clinical signs and not the incomplete ossification of the humeral condyles. In the future, the incomplete ossification of the humeral condyles may develop into a pathological fracture.

    NEXT STEPS:
    – I would like to assess the remainder of the elbows to look for other changes associated with elbow dysplasia such as cubital joint incongruity, osteochondritis dissecans of the medial humeral condyle, or any other associated subchondral lesions (“kissing lesions”).
    – I would also like to refer to an orthopedic surgeon for further surgical treatment or medical management with pain medication and non-steroidal anti-inflammatory medications.

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