The patella is the bone we know as the knee cap. A groove in the end of the femur allows the patella to glide up and down when the knee joint is bent back and forth. In so doing, the patella guides the action of the quadriceps muscle in the lower leg.
The patella also protects the knee joint. Looking at the lower front portion of the femur (the thigh bone) in a normal dog, you will notice two bony ridges that form a fairly deep groove in which the patella is supposed to slide up and down. These structures limit the patella’s movement to one restricted place, and in so doing, control the activity of the quadriceps muscle. The entire system is constantly lubricated by joint fluid. It works so that there is total freedom of motion between the structures.
Luxating patella is the result of a malalignment of elements in the hind limb and/or shallow trochlear groove (the groove in which the knee cap sits). Repeat luxation damages the cartilage in the trochlear groove and the frequency of luxation may increase, this can causing inflammation and arthritic changes.
Hydrotherapy is now recognised as an ideal form of recuperative therapy for dogs, although they are on restricted exercise on land, they can extend their legs fully in the water and build up muscle around the joint to support the weaker areas. It is important that the amount and type of swimming and exercise is carefully controlled as studies have shown that too much exercise, too early can damage cartilage and soft tissues and delay recovery
- Buoyancy aids in the rehabilitation of weak muscles and painful joints
- Joints can be unloaded as a result of the buoyant properties of H2O
- Buoyancy counteracts weight which allows ambulation when weight-bearing is
- The viscosity of the water can assist in stabilising unstable joints (does the job that a bandage would)
- The hydrostatic pressure of the water decreases pain perception
- Relaxation of muscle tension and/or muscle spasm
- Swimming is non –weight bearing – less joint concussion on the joints
- Increased active range of motion in the water
- Feeling of well-being due to release of endorphins
- Reduction of frustration for dogs on cage rest or reduced exercise – less likely to be “uncontrollable” as on land
- Increased muscle strength
- Improved muscle patterning and recruitment
- Prevention of secondary complications
- Improved cardiovascular fitness
- Potentially earlier return to normal function
- Slowing of progression of degenerative disease processes
- Improved quality of life