Tendonitis in dogs – symptoms, investigations and treatment

Overview

A tendon transfers muscle force to bone

A tendon connects a muscle to its bony origin or insertion. It transfers the force of contraction to bone and moves a joint. A tendon can be strained, torn, cut or pulled from its attachment. The precise type of damage therefore affects treatment needs.

In tenosynovitis, inflammation affects the synovial tissue surrounding a tendon. The tendon sheath can expand as fluid increases. In biceps tendonitis, the affected site is around the shoulder.

A biceps tendon problem can cause long-standing forelimb lameness. Other shoulder diseases can nevertheless produce similar signs. Treatment is therefore not selected from lameness noticed by an owner alone.

In a group of 32 dogs with chronic biceps tendon problems, lameness had lasted 6–18 months before treatment. Mean duration was 12.5 months and median duration 13.35 months. This describes selected long-standing cases, rather than a waiting period before seeking investigation.

Causes

Strain, injury and shoulder joint disease

Biceps tendon inflammation may involve repeated strain injury, acute trauma or degenerative shoulder joint disease. A detached bone–cartilage fragment from shoulder osteochondrosis can also irritate the biceps tendon region. Biceps tendon inflammation is a possible consequence of severe shoulder osteochondrosis.

Repeated overloading has been proposed to cause bleeding into the synovial tissue surrounding the tendon and local swelling. Reduced tissue oxygen delivery may promote degeneration and calcification. Oxygen deprivation can encourage cartilage-like areas to develop within tendon tissue.

Tissue that repairs slowly

Blood supply arriving from outside the tendon forms only a small part of its overall supply. Most comes from the muscle–tendon junction and bony attachment. A tendon within a sheath also receives nourishment from synovial fluid. During scarring, collagen fibres become less regularly organised than before. Repaired tissue may therefore be weaker than the original tendon.

Risk factors

Biceps tendonitis has been described particularly in medium-sized and large, middle-aged or older dogs. No clear sex predisposition has been demonstrated. Intense or repeated shoulder loading is a possible contributing factor. A single trigger may nevertheless remain unknown.

The group of 32 dogs with chronic biceps tendon problems included dogs aged 2.5–7 years. Their weights were 15–31 kg.

The same 32-dog group had a mean weight of 22.82 kg and median weight of 22 kg. These are characteristics of the group studied, rather than age or weight limits outside which tendonitis cannot occur.

Typical symptoms

Lameness with biceps tendonitis may be progressive or recurrent. Typical observations include:

• Forelimb lameness more pronounced after exercise.
• Lameness easing with rest.
• Reduced shoulder movement.
• Gradual loss of muscle bulk around the shoulder.
• Pain during examination of the shoulder or biceps tendon.

Chronic pain can also appear as shorter walks or avoidance of stairs and jumping. Not every dog stops moving because of pain. Lameness easing at rest therefore does not mean exercise can resume without investigating the problem.

Persistent pain can also involve restlessness when finding a place to lie and more frequent position changes. Some dogs avoid touch.

Complications and consequences

Adhesions, rupture and persistent lameness

Adhesions between a tendon and its sheath can painfully restrict limb use. Inflammation can weaken the tendon's mechanical strength. In the worst case, it can rupture.

Lameness may return as exercise increases after treatment. Muscle wasting can accompany a chronic shoulder problem. Increasing inflammation can cause overgrowth and thickening of synovial tissue around the tendon. Activity is therefore resumed in stages according to the treatment plan.

Chronic pain can sensitise pain perception so that even ordinary touch hurts. Not every tendon change visible on imaging disappears completely as recovery progresses.

Diagnosis at the vet

A lameness examination locates pain

Your vet assesses whether lameness relates to the biceps tendon or another shoulder structure. Pressing the biceps tendon while flexing the shoulder and extending the elbow may cause marked pain. Shoulder range of movement and muscle wasting are assessed at the same time. Painful tests do not need repeating at home.

Tendon damage can be seen with ultrasound, arthroscopy or MRI. Shoulder arthroscopy allows examination of the whole joint. It can therefore also reveal another concurrent problem within the joint.

What do different images show?

X-rays may show tendon calcification or mineralised loose bodies in its sheath. Spurs along the humeral tendon groove can also be visible. Ultrasound assesses tendon structure and surrounding tissues.

Ultrasound can identify thickening, increased sheath fluid and partial tears within the tendon. Increased fluid is not, however, specific to biceps tendonitis. A limitation of ultrasound is incomplete visualisation of structures on the shoulder joint's inner side.

A joint fluid sample can help rule out infection or immune-mediated joint disease where necessary. The sample does not always give an unambiguous answer. The combined findings establish which structure is affected and what treatment it needs.

Ultrasound can often be performed without anaesthesia or sedation. It may also suit monitoring structural tendon changes during treatment. Image changes are compared with movement and the owner's pain observations.

Treatment

Relieving pain and reducing loading

Mild, recent biceps tendonitis can initially be treated with rest and an NSAID prescribed by your vet. Rehabilitation also forms part of small-animal tenosynovitis care. Appropriate treatment is selected according to the damage identified on examination.

Activity is usually restricted for at least 6 weeks with a biceps tendon problem. If lameness resolves, exercise is increased very gradually over the following 4–6 weeks. Signs may nevertheless recur as loading increases. These are stages of activity restriction, rather than instructions on medication duration.

Rehabilitation and local treatments

Initial physiotherapy assessment examines movement restrictions, muscle wasting and reduced limb weight bearing. Exercise goals are based on the dog's problems, such as improving muscle strength or range of movement. The owner receives an individual home exercise programme. Exercise difficulty is therefore tailored to the investigated tendon injury and its healing.

Your vet may also consider intra-articular treatments such as a corticosteroid, hyaluronic acid or platelet-rich plasma, or PRP. A corticosteroid and an NSAID are not used concurrently. Medication compatibility is checked with the treating vet.

Tendon rehabilitation may also use laser therapy, shockwave therapy and manually guided exercises. Results are reassessed during rehabilitation. A single treatment session therefore does not replace the overall plan guiding loading.

Surgery for a persistent problem

Surgery may be considered if chronic biceps tendon disease does not respond to other treatment or a tear is identified. Tenotomy involves controlled cutting of the tendon. Tenodesis changes its attachment to the upper humerus. Bone–cartilage fragments within the joint can also be removed.

Arthroscopy allows biceps tendon release under direct visualisation. Recovery prognosis is generally good. Evidence comparing surgery with conservative care nevertheless remains insufficient to establish the general superiority of one method.

How long does recovery take?

In a small biceps tendon follow-up series, lameness improved in 10 of 11 conservatively treated dogs by the 6-week reassessment. Resolution of lameness nevertheless ranged from 2 weeks to 7 months. This was the series' outcome, rather than a deadline for an individual dog.

In another series, achieving a good or excellent surgical result took 2–9 months. Of 12 operated shoulders assessed clinically in that series, 8 were rated excellent and 4 good. These were assessments of small treated patient groups without a randomised comparison group.

In a small long-term follow-up, 11 of 13 conservatively treated dogs achieved good or excellent function. In another series, the clinical outcome was good or excellent in only 7 of 17 conservatively treated shoulders assessed. Results from these different patient groups also illustrate variation in response.

In 32 dogs receiving stem cells and PRP, ultrasound changes were monitored over 4 months. Reduced lameness and pain and improved limb function were observed during treatment. There was no comparison group, so the change cannot establish that this treatment is better than alternatives.

Prevention

Reducing repeated overloading is reasonable because it is among the possible causes of tendonitis. Rehabilitation is planned to account for restricted movement, muscle weakness and uneven limb loading. A long-term goal may be reducing recurrence of strain injury or pain.

Return to exercise is not rushed when lameness improves. Increased loading can bring signs back. Home exercises and their timetable are individually planned. One dog's successful recovery therefore cannot provide an exercise programme suitable for every tendon injury.

Important for dog owners

Record exercise and changes in lameness

Note which exercise makes lameness worse and how rest affects it. Also monitor stair use, jumping and walk lengths. Describe when signs began and whether they have increased. Follow-up can then assess functional changes using similar everyday situations.

Some veterinary physiotherapy services require referral or veterinary consent to treat an ill dog. Rehabilitation is carried out with the owner and treating vet. Do not give human pain medicines without veterinary instructions.

Clearly reduced limb use, new severe pain or a change in general condition requires prompt assessment. Previous tendonitis does not mean every later episode of lameness is the same problem.

Frequently asked questions

How can you recognise biceps tendonitis in a dog?

A common sign is persistent or recurrent forelimb lameness that worsens with exercise and eases at rest. Shoulder movement can decrease and muscles waste. Other shoulder diseases cause similar signs, so investigations confirm the diagnosis.

Does tendonitis show up on an ordinary X-ray?

An X-ray can show calcification, bone spurs or mineralised bodies within the tendon sheath. Tendon damage can be examined through ultrasound, MRI or arthroscopy. Imaging is selected according to the structure needing investigation. X-ray findings are therefore considered alongside the lameness examination.

How long does a dog's tendon problem take to heal?

Exercise is often restricted for at least 6 weeks with a biceps tendon problem. Once lameness resolves, loading is increased gradually over the following 4–6 weeks. In a small patient series, resolution of lameness ranged from 2 weeks to 7 months. Your dog's timetable therefore depends on the damage and reassessment results.

Does tendonitis need surgery?

Mild, recent biceps tendonitis may be managed with rest, medication and rehabilitation. A persistent problem or confirmed tendon tear may need surgical assessment. The technique depends on findings. Your vet may consider releasing the tendon or changing its attachment.

Can a dog exercise if lameness eases at rest?

A biceps tendon problem can specifically involve lameness easing at rest but worsening with exercise. Loading is increased only very gradually and according to the treatment plan. Signs may return as exercise increases. Briefly moving well therefore does not replace agreed restrictions and monitoring of healing.