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Case Report: Un-united Caudal Glenoid in a Labrador Retriever

A four-year-old female, neutered Labrador Retriever was presented with left thoracic limb lameness of several months duration.  Onset was insidious and severity was progressive, but noted especially after rest following exercise. 

fig.1 — mediolateral radiograph of left shoulder, showing mineralised mass at the caudal rim of the glenoid

The referring veterinary surgeon had detected pain on manipulation of the left shoulder.  Radiology had revealed a mineralised mass at the caudal limit of the glenoid (see fig 1) consistent with un-united caudal glenoid. 

There had been a good response to rest and meloxicam therapy.

Orthopaedic examination revealed no evidence of muscle atrophy or lameness on gait analysis, but there was consistent and repeatable resentment of extension of the left shoulder. 

Treatment

Exploratory arthrotomy was performed via a standard caudolateral approach to the left shoulder. 

Probing of the caudal glenoid revealed a loose, bony fragment which was removed.  The humeral head was inspected for signs of abnormalities but was found to be normal.  The joint was flushed and closed routinely. 

The patient was confined to short lead walks for six weeks postoperatively before progressive increase in exercise was allowed.  Three months after surgery, there has been no recurrence of the lameness and the shoulder remains pain-free on manipulation.

Discussion

Un-united caudal glenoid is a rare manifestation of osteochondrosis, seen mostly in large breed dogs as a chronic, low-grade lameness.  It results from a failure of fusion of the main body of the glenoid and the separate centre of ossification of the caudal rim.  Mineralisation of this junction should normally be complete by nine months of age.  Such radiographic findings may be incidental, so it is important to exclude other, more common causes of lameness with a thorough orthopaedic assessment which may require further imaging of other joints in the limb where appropriate.  However, any patient with a lameness referable to the shoulder joint with this characteristic radiographic appearance is a candidate for surgical assessment – either  arthroscopically or via arthrotomy. Loose fragments should be debrided as they would otherwise continue to act as a free body within the joint, causing synovitis and pain.  Long term sequelae are minimal, but a degree of osteoarthritis is inevitable.