Treatments for musculoskeletal disorders in active working dogs

Dogs are used in many roles to assist man complete tasks or “work”. This relationship is built on the ability for dogs to be readily amenable to training.

Many of the activities that working dogs are used for rely on their athletic ability. Therefore, anything that compromises athletic ability has a significant impact on that dog’s capacity to work.

Studies looking at various working dogs have shown that musculoskeletal (MSK) disorders are one of the, if not the most likely, reasons a dog would be lost from the workforce^1-3.

Consequently, being able to acutely identify and treat MSK pathology in working canines may allow dogs to have a more rapid and successful return to work.

A knowledge of the types of MSK conditions suffered by working dogs will be vital to those veterinarians, and other canine care professionals, who treat these patients.

Due to their specific tasks, working dogs can be predisposed to specific injuries. These may be due to the locations in which they work or the type of work that they conduct.

Specifically, if dogs perform repetitive actions while working and overwork certain tissues, they can be predisposed to repetitive strain injuries and tissue degeneration.

It is also noteworthy that many breeds of dog exist, but usually, relatively few are used for specific working roles. Dogs have been bred for the role. Therefore, many MSK disorders seen in working dogs are heritable breed-related conditions.

Knowledge of the common conditions seen in that specific canine job role, and in that specific breed, can give a clinician a good idea of what the problem may be before the patient even walks into the consulting room.

This “pattern recognition” can be very useful and more often or not will provide an accurate diagnosis.

However, the need to keep an open approach should always be remembered. At the end of the day, the patient is a dog; just because they are a working dog does not mean they need a “canine sports medicine” diagnosis. Dogs can succumb to any MSK condition that any breed of companion dog may suffer.

Law enforcement

German and Belgian shepherd dog breeds are frequently used by the military and police. Their work may mean they spend a lot of time resting in a confined space (for example, the back of a police vehicle) and then suddenly must sprint into action. This lack of a “warm up” prior to intense physical activity can predispose to muscle strains. Muscles are more likely to sustain an injury during an eccentric contraction.

Muscle injuries can be marked (with significant pain, swelling or haemorrhage⁴) requiring weeks or months of recovery, while others can be subtle and show improvements within a few days. The iliopsoas and sartorius are commonly reported casualties⁵.

Another muscular disorder that plagues these breeds is contracture of the gracilis and semitendinosis/semimembranosus^{6, 7}. This results in the pathognomonic gait pattern; short stride with rapid elastic inward rotation of the paw and internal rotation of the stifle.

Degenerative stenosis of the lumbosacral spine is one of the most frequently diagnosed conditions that the author sees in working police dogs. For dogs that complete any “work”, this can be a common condition they develop, with repetitive strains across this junction an underlying culprit. Dehydration and protrusion of the L7-S1 intervertebral disc, proliferation of ligaments and spondylosis can lead to compression of the L7-S1 neuroforamen (Figure 1).

Treatment can involve exercise/lifestyle modification to avoid movements that cause pain, rehabilitation, systemic medical management (such as gabapentin)⁸, local medical management (epidural methylprednisolone/platelet rich plasma)^9-11, or surgery (decompression alone, or with concurrent distraction/stabilisation)^{12, 13}.

Farm/herding dogs

Collie breeds are the most likely breeds to be used on farms to assist in herding livestock. Traumatic injuries to the lower limbs can occur from being caught in cattle grids, trampled by animals, uneven ground surfaces and farm machinery. This can result in wounds, dislocated phalanges, ligament strains and fractures.

Although poorly understood, carpal and tarsal joint collapse is seen more commonly in Shetland sheepdogs and other collie-type breeds¹⁴ (Figure 2).

Pancarpal arthrodesis would be the surgery of choice for carpal collapse and, promisingly, 83% of farm dogs were reported as able to return to work following this procedure^{15, 16}.

These same breeds also have a high prevalence of luxation to the superficial digital flexor tendon¹⁷. Luxation can be corrected with surgery to repair the torn retinaculum.

Border collies are one of the most common breeds to be diagnosed with osteochondrosis of the humeral head¹⁸ (Figure 3). Surgery can be performed to remove the loose cartilage flap either arthroscopically or via an open approach^{18, 19}.

To resurface the cartilage defect, osteochondral grafts^{20, 21} or synthetic implants²² can be placed. Alternatively, techniques to encourage fibrocartilage formation, such as “microfracture/micropicking”, can be used.

Injuries to the musculotendinous anatomy of the shoulder (supraspinatus, biceps, medial shoulder stabilisers) are seen more frequently in border collies, with repetitive strains during athletic activities a believed aetiology²³ (Figure 4).

Detection/search and rescue

Spaniel breeds are frequently used for detection and search and rescue roles. Spaniels are over-represented for developing humeral intracondylar fissures, and this should always be a consideration for a thoracic limb lameness in this breed²⁴ (Figure 5).

Originally believed to be due to incomplete ossification of the humeral condyle, an understanding now exists that these are usually developmental fissures^25-27. Although not conclusive, an increasing thought persists that the cause is due to humero-ulnar/anconeal incongruity²⁸. To reduce lameness from the fissure and/or to prevent humeral fracture, surgery can be performed by placement of a transcondylar screw^{29, 30}.

Although it can be associated with any intensive exercise, the “classic” narrative for acute caudal myopathy (“limber tail”) is that this occurs following cold water swimming. Therefore, this may be seen in water rescue dogs (or any working dog – especially the Labrador retriever)³¹.

Service dogs

Service dogs most frequently assist people with disabilities or those who need additional physical/emotional support. Labrador and other retrievers are the most common breeds used for these roles due to their friendly nature and adaptability. They typically lead a less intensive physical lifestyle compared to some of the working dogs already discussed. Therefore, the musculoskeletal disorders they encounter are more commonly because of their breed, rather than activity.

The most commonly associated orthopaedic conditions with these breeds are hip dysplasia (HD), developmental elbow disease (DED), and cranial cruciate ligament (CCL) disease. Breeding programmes can help to reduce the prevalence of HD and DED³² (Figure 6).

Vast amounts of time and money are invested into training these dogs and, as a result, they are frequently from good breeding stock, so the incidence of these conditions will hopefully be lower than that in a typical companion dog. It is important to try to identify these conditions early in life so that, if necessary, dogs can be withdrawn from training programmes. Those that have already began work will likely have formed strong relationships with their handlers and therefore will want to maximise their ability to continue to work.

Stifle instability due to cranial cruciate ligament rupture will be a common differential diagnosis of canine pelvic limb lameness in both working and companion dogs (Figure 7). Working dogs may be more likely to sustain a “true” traumatic rupture to the CCL, and care should be taken not to misinterpret a caudal cranial cruciate ligament, or multi-ligament rupture, as solely a CCL tear.

A knowledge of the tasks they perform, and breed predispositions, can aid veterinarians to formulate their differential diagnosis list when treating working dogs. Careful physical examination and appropriate diagnostics can be undertaken to achieve an accurate and timely diagnosis, so that a precise prognosis can be communicated, and therapy can be initiated early in an attempt to restore the ability to work.