Use of canine hydrotherapy as part of a rehabilitation programme

Current usage of hydrotherapy facilities

Most dogs using hydrotherapy centres in the UK are pedigree breeds, with the Labrador retriever representing 30% of all dogs seen (Waining et al, 2011). This could be because of the breed’s popularity, making up 8.2% of the overall dog population in the UK, susceptibility to musculoskeletal conditions or reputation as a good swimmer; thus owners are more likely to follow veterinary advice by taking their dog for hydrotherapy as part of a rehabilitation programme or they may simply be more likely to take their dog swimming for fun and fitness (Wain-ing et al, 2011).

Waining et al (2011) examined the reasons dogs were referred to a hydrotherapy facility, and found that 25% had suffered a cranial cruciate ligament rupture, 24% had hip dysplasia (HD) and 18% had oste-oarthritis, which highlights the common conditions for which hydrotherapy is used in the UK.

Properties of water

A number of the properties of water can be harnessed for use in canine hydrotherapy. A good understanding of these properties is needed for the design and implementation of a specific programme tailored to meet the needs of an individual dog, particularly for those dogs suffering from musculoskeletal conditions, as is the case in human hydrotherapy (Edlich et al, 1987).

Buoyancy

The principle of buoyancy was defined by Archimedes; when a body is wholly or partially immersed in a flu-id, the body experiences an upwards thrust equal to the weight of the water that it has displaced (Edlich et al, 1987). This means that in the pool, the dog’s mass is supported by the water and the dog’s limbs have a greater range of motion without putting joints under strain.

The water level of an UWTM can be changed as required, and the percentage bodyweight carried by a dog’s limbs while using the treadmill can be changed by varying depth — the deeper the water, the less bodyweight loaded onto the limbs (Levine et al, 2002).

Viscosity

The friction between water molecules, described as viscosity, provides resistance to the animal moving through it (Monk, 2007); this slows a dog’s movements compared with when on land, and reduces the likelihood of injury from sudden movements (Prankel, 2008). The viscosity also helps to build muscle strength and subsequent fitness (Sharp, 2008).

Surface tension

Surface tension is the force exerted between molecules at the surface of a body of liquid (Monk, 2007); thus there is more resistance to movement at the surface. This means that when a dog is swimming as part of a rehabilitation programme and its muscles are weak, it will find it hard to break the surface of the water with a limb; however, the dog would be able to move its limbs through the water below the surface. Care should be taken to avoid limbs thrashing above the surface of the water, as this will lead to excess energy expenditure.

Hydrostatic pressure

Pascal’s law states that fluid pressure is exerted on all surfaces of an immersed body while at rest and at any given depth (Monk, 2007). Hydrostatic pressure is the sum of this pressure on a body surface (Connell and Monk, 2010), which can have a massaging effect and reduce oedema by aiding venous return (Prankel, 2008).

Temperature

The water in which hydrotherapy takes place should ideally be between 26–30°C in order to increase the elasticity of cells, promote relaxation and provide pain relief (Prankel, 2008; Sharp, 2008; Rodrigues et al, 2011). The warm water also dilates the blood vessels, enabling more oxygenated blood to circulate around disused muscle cells, helping to eliminate the toxins that will have built up during their inactivity (Blundell, 2011).

Veterinary consent

Under the Veterinary Surgeons Act 1966 (Royal College of Veterinary Surgeons, 2010), responsibility for the diagnosis of an animal’s condition lies solely with the veterinary surgeon. It is not only good practice for the referring veterinary surgeon to complete a consent form giving permission to commence hydrotherapy, but it is also a requirement of both the Canine Hydrotherapy Association and the National Association of Registered Canine Hydrotherapists within the UK. A completed consent form may also aid the hydrotherapist in understanding the dog’s condition. It is important that the animal’s progress is discussed by the veterinary surgeon and hydrotherapist, so that adjustments to treatment can be made where appropriate (Prankel, 2008).

What is hydrotherapy used for?

A study by Waining et al (2011) focused on the use of canine hydrotherapy facilities within the UK. These facilities are used by a wide range of clientele for a number of different reasons, including as part of obesity management programmes. Many dogs are classed as overweight or obese, which is associated with orthopaedic disease (German, 2006). A study of Labrador retrievers found that dogs fed ad libitum were heavier than those fed a set amount of food twice daily, and suffered from a higher incidence of HD (Kealy et al, 1992). The cycle of weight gain associated with HD typically begins with the intake of excess calories leading to weight gain; degradation of joints occurs as a result of the extra mechanical stress caused by this weight and osteoarthritis with associated pain develops, which can lead to reluctance to exercise and further weight gain. Hydrotherapy can be used here as exercising in water is often less painful because of decreased joint loading, and weight loss occurs as a result of the utilization of energy reserves (Chauvet et al, 2011).

Dogs can build and maintain fitness during hy-drotherapy sessions (Figure 1), and training such as in-water retrieval can also take place in a pool. Hydrotherapy can be used in pre-operative muscle conditioning, such as before a hip replacement, with the aim of reducing recovery time (Prankel, 2008). It can also be used as part of the conservative management of developmental orthopaedic diseases in dogs, such as HD and osteochodrosis dessicans (LaFond et al, 2002). The progression of chronic degenerative radiculomyelopathy can be slowed (Kline, 2002), and hydrotherapy has its place post operatively, aiding in the recovery from orthopaedic surgery such as the repair of a cranial cruciate ligament (Monk et al, 2006). The start date for hydrotherapy varies between conditions and the surgical technique used, as some require a longer healing time before rehabilitation can begin. With some surgeries, this can be as early as 14 days post operatively, once wounds have healed (Connell and Monk, 2010).

Dogs that are suffering from intervertebral disc disease may regain some function post operatively through hydrotherapy; if surgery is not an option for that animal, hydrotherapy could be used to maintain mobility and relieve pain (Kline, 2002). Hydrostatic pressure on a dog’s limbs can help with posture re-education. Hydrotherapy may also be used palliatively to provide some pain relief, enabling dogs suffering from terminal disease, such as an os-teosarcoma, to exercise in a safe environment (Prankel, 2008; Sharp, 2008).

Emotional wellbeing can be improved through relaxation and endorphin release when in the water (Randall, 2010), and some owners have reported a renewed vigour in their dog (Prankel, 2008). Evidence from human hydrotherapy suggests that the energy cost of swimming is approximately four times that of running the same distance on land, and this theory has been applied in canine hydro-therapy (Monk, 2007).

Contraindications

Even though written consent from a veterinary surgeon is a prerequisite for hydrotherapy, it is important for the hydrotherapist to assess each dog before the commencement of every session to ensure fitness to take part.

The therapist needs to recognize any conditions that would be classed as a contraindication, such as:

In humans it has been suggested that massage therapy and hydrotherapy may increase the incidence of tumour metastasis, as a result of the increased blood and lymph flow to the areas treated (Curties, 2000). This may also be the case in dogs, although further work is needed in this area.

The hydrotherapist may not be physically able to handle an aggressive dog in the water; if the veterinary surgeon feels that the dog will benefit from receiving hydrotherapy, other steps may have to be taken to enable the session to take place, such as conducting the session from the side of the pool or on an UWTM. This should ensure that the safety of the dog, therapist or owner is not compromised. Pain can cause defensive aggression, which can explain why a typically placid dog may display uncharacteristic behaviours (Borchelt, 1983). An understanding of what is deemed a sensible reason to terminate a session early is essential, with reasons including getting overly stressed, emesis or defecation in the water, swallowing excessive amounts of water, choking, aggression and fatigue.

A veterinary surgeon may refer a dog for hydro-therapy that suffers from a condition that would ordinarily contraindicate commencement of therapy, believing that the benefits outweigh the risk to the animal’s health; this should be discussed with all parties involved. For example, an ageing, overweight cross-breed with laryngeal collapse referred for hy-drotherapy as post-operative rehabilitation for a cranial cruciate repair should ideally use an UWTM as opposed to a swimming pool, as this will cause less respiratory distress. Great care should be taken to monitor the dog continually and to recognize fatigue and signs of respiratory distress.

From the wide range of uses of hydrotherapy, two case studies have been selected for presentation: the conservative management of HD in a young male Labrador retriever (Case study 1); and post-operative rehabilitation of a paraplegic female Border Collie with multiple pelvic fractures following a road traffic accident (Case study 2). Both animals received veterinary treatment at Hillcrest Animal Hospital, Chorley, and used hydrotherapy facilities at Canine Therapies, Preston.

Conclusion

Canine hydrotherapy is used for a number of reasons in the form of a swimming pool or an UWTM. It is important that the veterinary surgeon works closely with the hydrotherapist when they refer patients, as this will help in the creation of a tailored treatment plan for that individual patient. Although research into the benefits of canine hydrotherapy has been published for a number of conditions, future work is needed in order to quantify its value within the veterinary world. This research should help to demonstrate the different areas in which hydrotherapy can help dogs, and should increase the level of awareness among veterinary professionals of the benefits gained from hydrotherapy in both first opinion and referral practice.

Case study 1.

Conservative management of hip dysplasia in a young male Labrador retriever

In January 2008, a male Labrador retriever aged 1 year was diagnosed with bilateral hip dysplasia (HD) following presentation of intermittent lameness of both hindlimbs. The veterinary surgeon advised a prescription joint food, a 14-day course of non-steroidal anti-inflammatory drugs (NSAIDs) and hydrotherapy. The aim with hydrotherapy was to build up the muscles of the hindlimbs and pelvic area so that they were able to support the hip joints. The hydrotherapy took place in a swimming pool with a hydrotherapist three times a week for the first 3 months.

The first session involved the dog swimming for approximately 30 seconds and resting on the steps of the pool for 5 minutes, repeated five times. The time spent swimming was gradually increased over a period of 36 sessions to 25 minutes per session, with shorter breaks of 30 seconds interspersed between swims of 2 or 3 minutes. At this point the hydrotherapist was happy for the dog to swim unassisted, as he had a good range of motion through his hips; he swam three times a week for the next 3 years for fun and fitness, maintaining the muscle mass of the affected areas, and being directed by his owner from the side of the pool. He showed no signs of lameness during this time.

In May 2011, at the age of 4.5 years, he became lame; radiographs confirmed that the lameness was caused by advanced osteoarthritis in both coxofemoral joints as a result of HD. Photo 1 shows that both femoral heads are angular, the joint capsules are thickened and the cranial edge of the right acetabulum has a bony spur. The right femur is severely displaced as a result of these changes. The veterinary surgeon prescribed long-term NSAIDs and the dog continues to swim twice a week, not only to maintain the muscles built up during hydrotherapy and to prevent atrophy, but also to allow him to exercise in a safe, non-weight-bearing environment and to help maintain his weight and fitness levels.

Case study 2.

Post-operative rehabilitation of a paraplegic female Border Collie with multiple pelvic fractures following a road traffic accident

In April 2011, a female Border Collie, aged 10 years, presented with multiple fractures to both sides of the pelvis following a road traffic accident. Fractures were present in the right wing of the ileum, pubis and ischium and left pubis and ischium, and there was a sacroiliac separation in the left pelvis. The nature of this fracturing effectively disconnected both hind limbs from the spine (Photo 2).

A four-hole plate was used in the right wing of the ilium and a single lag screw was used to reattach the left wing of the ilium to the sacrum. The procedure realigned the remaining fragments that were left to repair without the need for further implants (Photo 3).

In the weeks following her operation, she was non-weight bearing, not aware of her need to toilet and had great muscle wastage, but had some feeling in her tail. By 4 weeks post operatively she had regained some sensation in her hindlimbs and tail, with slow withdrawal and deep pain reflexes. She began hydrotherapy at this point in a swimming pool with two therapists — one to steer, the other to encourage movement of the hind limbs.

The first session involved swimming for 30 seconds followed by a rest of 5 minutes, repeated four times. The aim of hydrotherapy was to encourage her to use her hind limbs in the non-weight-bearing environment of the water in order to build up those muscles lost through atrophy; it was hoped that once this had begun, she would be able to support her own weight on land. During her second session, she was able to move her hindlimbs in the water by herself, and by the sixth session was able to swim with just one hydrotherapist (Photo 4).

She swam six times a week, and by the ninth week after surgery was aware of her need to go to the toilet. Her hydrotherapy sessions had built up to 50 minutes in total, consisting of repetitions of swimming for 2 minutes followed by resting for 30 seconds. There was a marked increase in her hindlimb muscle mass by this point. She was able to support her own weight on all four limbs without the help of a support sling, and by 3 months post operatively she was able to take a few steps unaided. If the centre had not had a pool and only an UWTM had been available, this could have been used; a support sling would have been held by one therapist with another therapist placing both hind feet individually on the UWTM as it moved slowly along, so as to avoid knuckling and scuffing of the feet.

In the next few weeks, her owner felt that her progress on land had begun to plateau and she panted for the first time during a hydrotherapy session. There was deterioration in her condition in the following days and further investigations revealed an abdominal tumour. The decision was made to put her to sleep. This poignant and moving case highlights not only the positive effect that hydrotherapy can have in such rehabilitation cases, but also that small changes noted by the hydrotherapist can be of great significance in the treatment programme of that animal.

Key Points