Musket: Pioneering non-surgical treatment of shoulder lameness

Musket is a 2 year old, active large breed male dog who presented to SVS with an 8 month history of left forelimb lameness. The lameness waxed and waned depending on his activity, but would never disappear entirely. There were some days that Musket was so sore that he was sometimes not using the leg at all, and his ability to run and play was severely diminished. Even with rest and anti-inflammatories (NSAID's), Musket's lameness just did not get better. Radiographs (X-rays) of Musket's shoulders did not reveal any problems with his bones or joints, so that left a soft tissue or neurological lesion as a possible cause of his pain.

Musket was seen at SVS by Dr. Kirkby who found that he was painful in his left shoulder on physical examination. An ultrasound and MRI of the shoulders and neck were ordered to see if the problem was associated with his tendons in his shoulder or potentially a nerve being compressed in his neck. Sometimes nerve problems can present very similar to soft tissue injuries of the forelimb, so they need to be ruled out. Ultrasound is capable of looking only at the tendons in the shoulder, whereas MRI is needed to examine the spinal cord, nerves and muscles.

Figure 1 - view of the inside of the shoulder. The red arrow shows where Musket's supraspinatus tendon injury was found. The blue arrow represents the biceps tendon that was also affected

The ultrasound showed enlargement of his left supraspinatus tendon that was causing compression of his biceps tendon and increased fluid in the biceps tendon sheath. In comparison, his right shoulder showed similar but milder signs. The MRI did not show any nerve compression or abnormalities, so the scan was continued to his shoulders which better defined the left shoulder tendon abnormalities. The left supraspinatus tendon was confirmed as being abnormal and causing impingement and consequent irritation of the biceps tendon.

In humans, this condition is known as a rotator cuff injury. Traditional treatments for this condition in dogs have been either medical, using rest and anti-inflammatories or steroids, or surgery in refractory cases. Medical treatment is usually unsuccessful over long periods of time. Surgical treatments are based on either cutting the tendon (tenotomy), removing part or all of the diseased tendon (tenectomy), or sometimes cutting it from its origin and replacing it further down the arm (tenodesis of the biceps). Results of surgery vary, but good outcomes are reported in about 65-90% of cases.

Tendonopathies of the shoulder have been demonstrated to be non-inflammatory, progressive, degenerative processes. This means that the body attempts to heal injured tendon, but fails due to poor blood supply and abnormal healing processes. Recent information from human studies have shown that non-surgical treatment using either high-powered ultrasound (extracorporeal shockwave therapy; ESWT) or laser therapy ( i.e. cold laser) in combination with rehabilitation exercises may be able to stimulate and improve the natural healing process of tendons. One study has shown that ESWT outcomes were as good as arthroscopic surgical treatment outcomes in humans.

ESWT and laser have been used to treat soft tissue injuries in dogs for several years with very good clinical results. However, no studies in veterinary medicine have compared these two treatments as non-surgical options for shoulder tendon injuries.

After being diagnosed with a shoulder tendinopathy, Musket began therapy with ESWT every 3 weeks for a total of 3 treatments. During this period, at home rehabilitation exercises and controlled activity were required, which meant that Musket was not allowed to run free or play, even though he started to feel better because he could easily reinjure himself. After the third treatment, Musket's owner was taught new rehabilitation exercises and his activity level was increased, though he was still not allowed uncontrolled off leash play time.

Ten weeks after the initial treatment Musket was reassessed by Dr. Kirkby and found to be no longer lame on his left forelimb and his owner reported a huge clinical improvement. Over the next few months Musket's activity levels were increased and his restrictions were eased. Six months after the first ESWT treatment, Musket is back to himself and enjoying life, pain free and without the need for surgery.