Disorder - Shoulder luxation

Organ Systems Involved
Musculoskeletal

Alternative disorders described within LIDA

Glenoid dysplasia; Degenerative joint disease

Alternative Names
Dislocation of shoulder; Sub-luxating shoulder; Congenital shoulder instability

Presenting Signs

Acquired shoulder luxation in cats usually occurs as a result of trauma, and affected cats generally have normal bone structure. In contrast, congenital shoulder luxation occurs as a result of a defect in one of these bone structures. Defects can include a flattened humeral head (the rounded end of the long upper arm bone) or a shallow glenoid (the two bony structures that make up the shoulder joint). These bony defects cause the shoulder joint to be unstable, and this causes movement (luxation) of the two bones that make up the shoulder. Typically, cats are lame in the affected limb.

Cats that suffer from this congenital abnormality often have a limited range of motion in the affected limb, and are particularly unable to extend the leg forward when it is manipulated. This may also be associated with pain or discomfort on doing so. The condition can be diagnosed with X-rays of the affected limb, which helps show the shallow meeting of the joint and/or displacement of the bones. Associated muscles may be wasted in the affected limb in chronic cases as a result of the cat favouring its normal front limb over the luxating one.

Cats at Risk

Congenital shoulder luxation is extremely rare in cats with very few reported cases in the literature.

Treatment

Medical: restriction of activity and administration of analgesics. Surgery is generally not carried out as it requires reshaping of the joint and can result in joint ankylosis (fusion) or painful arthritis.

PubMed References
Shoulder luxation

Contributor
James Brown