The shoulder joint in the dog is made up of the larger spherical head of the humerus which sits in the shallow fossa (concavity) of the scapula (shoulder blade). The shoulder joint has the greatest range of motion of all joints in the canine but it is most frequently moved linearly in extension and flexion. Its stability is controlled by multiple structures including: rotator cuff muscles, joint capsule, joint fluid and shoulder ligaments.
It is thought most shoulder instabilities are due to chronic overuse. It is often seen in active working dogs but is also possible in couch potatoes who repeatedly jump from the lounge chair. In some small dogs it may be due to a congenital abnormality which means they are born with a weakness of the structures surrounding the shoulder leading to instability.
The vast majority of unstable shoulder joints in dogs are due to medial shoulder instability (about 80%). That is the structures that help keep the shoulder in against the body. In these cases there is a tendency for the shoulder to abduct (pop out away from the body).
The remaining 20% of unstable shoulder joints are either unstable on adduction (tend to pop out inwards towards the body) or are unstable in multiple directions.
Shoulder instability is suspected in dogs with short term or long term forelimb lameness. Some small dogs with congenital instability on both sides may not show obvious signs of lameness and may appear to be walking normally.
Palpation by your vet checking for a "drawer" sign of the shoulder or by performing the medial shoulder instability test can help determine if there is shoulder instability.
Xrays may be helpful in diagnosis but ultrasound and arthroscopy are better at detecting damage to the tissues in and around the shoulder joint.
For acute sudden severe luxations due to sudden injury surgery is the treatment of choice. There are a range of techniques available. Prognosis is guarded in these circumstances.
The majority of shoulder instabilities are due to chronic overuse and up to two thirds of these cases will respond well to conservative therapy. Conservative therapy may include anti-inflammatory medication, therapeutic hobbles, manual therapies, home exercise program, extracorporeal shockwave therapy, pulsed electromagnetic field therapy and laser.
Conservative treatments offered by Balance Vet Rehab that may be beneficial for these pets include:
Shockwave (COMING SOON)
Shockwave therapy seems to be gaining favour as the initial treatment of choice for medial shoulder instability especially in the larger more prestigious rehabilitation centres.
Evidence for minimally invasive therapies in the management of chronic calcific tendinopathy of the rotator cuff: a systematic review and meta-analysis K.G.Louwerens MD et al
Extracorporeal Shockwave Therapy for Shoulder Lameness in Dogs Willem Becker et al
Extracorporeal shockwave therapy and therapeutic exercise for supraspinatus and biceps tendinopathies in 29 dogs. J. Leeman et al
One of the newer therapies that can help in soft tissue injury but more studies are needed to fully assess benefit in dogs with shoulder instability.
PULSED ELECTROMAGNETIC FIELD THERAPY OF PERSISTENT ROTATOR CUFF TENDINITIS: A Double-blind Controlled Assessment AllanBinder et al
Gentle manual therapy can help reduce pain in these guys.
The Efficacy of Manual Therapy for Rotator Cuff Tendinopathy: A Systematic Review and Meta-analysis
Laser may help reduce inflammation and encourage healing in dogs with this condition.
A careful consideration of the home environment and activities in the home are essential to recovery after shoulder injuries. The appropriate gradual return to activities give the damaged soft tissues the best chance of regaining maximum strength.
Exercise for rotator cuff tendinopathy: a systematic review Chris Littlewood et al