Canine rehabilitation (Proceedings)

Rehabilitation can be defined as restoration following disease, illness, or injury, of ability to function in a normal or near normal manner. With respect to this abstract the injury I'll focus on is joint surgery in the dog for rupture of the cranial cruciate ligament. However, the principals apply to many orthopedic surgeries. With respect to restoration of function I'll draw your attention to the scientific literature and contrast that to the many opinions that have now been voiced regarding this topic.

Prolonged immobilization after joint surgery is closely associated with degenerative alterations in connective tissue, cartilage, ligaments, muscles, and bone-ligament complexes, while allowing for hypertrophy of periarticular fibrous tissue. Restricted knee motion after anterior cruciate ligament (ACL) reconstruction in people contributes to joint pain, muscle atrophy, decreased joint mobility, increased arthrofibrosis, soft tissue weakness and functional impairment. Loss of joint mobility and joint instability disrupt normal joint kinematics and can lead to osteoarthritis (OA). Loss of mobility causes pain and effusion after prolonged weight bearing, crepitus during extension, altered gait, decreased knee function, and reduces the likelihood of return to pre-injury function.

Alternatively, early motion and aggressive postoperative physical therapy after ACL surgery in people has been reported to improve prognosis. Early physical therapy results in earlier and more complete return to function, often by 4-6 months after surgery, reduces re-injury rates while not increasing intra-articular graft failure rates. In athletes recovering from ACL surgery, it has been reported to reduce pain, joint effusion, capsular contraction, and periarticular fibrosis while increasing range of motion, muscle mass and limb strength. Finally, Shelbourne et al. and others have suggested that early postoperative physical therapy reduced the development of arthrofibrosis and OA. More recent evidence has suggested that focuses on training muscles that require use of proprioceptive skills is advantageous. This can be performed in dogs by using cavalettis.

In animals, physical therapy has been suggested to decrease muscle spasm, promote tissue healing and repair, increase ROM, decrease edema, and increase muscle strength and endurance. Improved range of motion, cartilage nutrition, and orientation and strength of collagen fibers in the ACL grafts are additional beneficial effects of early motion following joint surgery. Millis et al. have suggested that low impact exercises, including swimming and walking, avoid worsening of OA while maintaining muscle strength, joint mobility, and function. Finally, it has been reported that physical therapy after joint surgery decreases adhesions, is valuable for maintenance of muscle mass, bone, cartilage and ligaments, and provides the stress needed for reorganization of transplanted tissues.

Rupture of the cranial cruciate ligament (RCCL) is a common cause of lameness and the number one diagnosed stifle injury in the dog. While much attention has been given to the role of various surgical techniques for repair of RCCL, peer-reviewed literature addressing the role of postoperative management for dogs is scarce. Anecdotal reports several text books and manuscripts addressing surgical techniques for the ruptured cranial cruciate ligament suggest postoperative management should include application of a Robert Jones bandage for up to 14 days and activity restricted to a leash for up to 12 weeks. Much of this management is seemingly geared towards increasing the strength of periarticular fibrous tissue and mechanically protecting the repair technique. One could argue that this approach may actually increase the likelihood of a poor outcome for patients.

One of the first investigations in veterinary medicine looked at the effect of early postoperative physical therapy on limb function in dogs after surgery for RCCL. In this study, twenty-five dogs were included in a postoperative physical therapy group and twenty-six dogs were included in an exercise restriction group. Rehabilitation in this report focused on swimming, stretching and range of motion exercises and leash walking. Rehabilitation began 10-14 days following arthrotomy. Vertical forces were measured using force plate gait analysis preoperatively and six months after surgery. Prior to surgery vertical forces were statistically similar between groups. Six months after surgery, vertical forces in dogs in the physical therapy group were significantly greater than in dogs in the exercise restriction group. Peak vertical force (PVF) in dogs in the physical therapy group was 18.5% greater than dogs in the exercise restriction group, vertical impulse (VI) was 13.9% greater, and dogs in the physical therapy treatment group reached vertical forces that were statistically identical to that of the opposite normal limb. Considering these findings, it is reasonable to suggest that the after surgery for RCCL dogs benefit from postoperative physical therapy and that it should be considered as part of the care provided to these patients.

Perhaps one of the main benefits to physical therapy after joint surgery is limiting the development of periarticular fibrosis. Limiting arthrofibrosis not only allows for maintenance of range of motion and improved limb function but also reduces periarticular pain. A recent study investigated the range of motion in normal dogs and in dogs after surgery for a cranial cruciate ligament injury when they participated in terrestrial and aquatic activities. This investigation found that the range of motion in the hip, knee, and hock joints was dramatically greater during aquatic activities when compared to terrestrial activities. The principal benefit was seen with an increase in flexion of the joints during swimming. During walking and trotting dogs still had near normal extension even after joint surgery. A recommendation from this study is that after joint surgery dogs should not only participate in postoperative physical therapy but that therapy should include both walking and swimming.

The greatest benefit of aquatic rehabilitation is that it provides for buoyancy, which decreases the effect of gravity. On land, joint reactive forces can reach several times body weight. In water the effects of gravity and axial loading can be significantly diminished or can be entirely eliminated if the patient floats. This does not mean that joint reaction forces are decreased. An alternation to swimming is the use of an underwater treadmill. One, however, must be cautious when expecting a reduction in ground reaction forces from buoyancy when using this method. Harrison et al. reported that in people at a fast walk the water level needed to be at the level of the neck in order to reduce ground reaction forces to <25% of that found on land. When the water level was at the level of the waist, ground reaction forces were still 75-100% of normal. This fact likely limits the benefits of most low water level aquatic activities. Additionally, muscle activation has been demonstrated to be decreased during aquatic exercise, allowing for earlier return to active motion while decreasing the risk of reinjury. During swimming viscosity provides for a multiplanar passive resistance that is equal to the force exerted by the movement. Slower movements exhibit lower resistive forces while faster movements are met with equally increased forces. Additional benefits of water include the effects of hydrostatic pressure and specific heat. It has been suggested that hydrostatic pressure can reduce joint edema and warm pools can promote relaxation of the patient, increase blood flow to the muscles, and decrease pain.

The veterinary literature consists of few peer-reviewed manuscripts addressing post-operative rehabilitation. Although much of what is suggested in proceedings and at meetings may be true only evidence-based medicine should dictate the techniques we use to manage our patients.

References

Marsolais GS, McLean S, Derrick T, Conzemius MG. Kinematic analysis of the hind limb during swimming and walking in healthy dogs and dogs with surgically corrected cranial cruciate ligament rupture. J Am Vet Med Assoc 2003 Mar 15;222(6):739-43.

Marsolais GS, Dvorak G, Conzemius MG. Effects of postoperative rehabilitation on limb function after cranial cruciate ligament repair in dogs. J Am Vet Med Assoc 2002 May 1;220(9):1325-30.

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