Barely noticeable rear pain: Active dogs who are slowing down for no apparent reason may be nursing their iliopsoas muscle.

Your dog’s enthusiasm for chasing balls seems to have dimmed. They’re slower. Not quite so quick at the start. Their stride seems shorter, and they may move unevenly, with one side not stretching out as far as the other. They are not quite lame, but they are not quite right either. Is it a problem? Possibly. Your dog may have stretched their iliopsoas muscle.

The iliopsoas (pronounced “ilio-so-as”) is a muscle and tendon combination that connects the pelvis
to the femur, which is the large bone in the hind leg between the hip and knee. It helps the hip flex and brings the leg forward. Somewhat like a “groin pull” in people, the iliopsoas can become injured by overuse and hyperextension of the leg.

In some cases, you may not even realize that your dog is handling a low-grade chronic iliopsoas injury. They don’t show any clinical gait abnormality, at least until they slip while turning or on winter ice, which exacerbates the problem, making your dog become more obviously sore or lame.

Dogs with an iliopsoas strain generally show pain and a slight lameness, but they usually don’t suddenly go lame and refuse to bear weight on the affected leg. Many dogs only show a shorter stride in the rear when trotting. This soreness can be unilateral or bilateral, depending on which sides are injured. An iliopsoas strain is usually chronic, building up due to repeated low-grade wear-and-tear on the muscle.

A common injury

An iliopsoas injury likely occurs more often than it’s diagnosed because it can be difficult to diagnose a soft-tissue injury.

“Strains of this muscle verified on imaging are very rare. In the sporting dog world, for a few reasons, these strains have been a common diagnosis to explain performance lameness based on palpation alone,” says Dr. Christopher Frye, assistant clinical professor and section chief of sports medicine and rehabilitation in the Department of Clinical Sciences.

“I do find this complex of muscle sensitive on palpation — when concurrently found with other hind-end disease (cruciate injuries, hip dysplasia, lumbar and lumbosacral disease). But a true primary sport-related strain is extremely unlikely to be a cause of lameness,” he says. “Because of this sensitivity finding when palpating that area, we then hypothesize that there is potentially a compensatory or overuse injury in that muscle group.”

Maryna Ozuna, an Arizona-based dog trainer who specializes in movement and behavior in dogs and the founder of Canine Kinesthetics, says that she is seeing an increase in dogs with iliopsoas problems due to life issues. She thinks the increasing suburbanization of dogs causes tightness in the loin muscles, especially the insertion of the iliopsoas at the pelvic rim, due to dogs hard-loading the hind muscles when walking and running on concrete. One study showed that a little more than 30% of all dogs with some hind-limb lameness included an injury to the iliopsoas.

Many dogs show a subtle intermittent lameness, for example, shifting more weight to the uninjured leg. Dogs who compete in canine sports may show problems specifically related to that sport. For example, a dog who competes in agility may start hitting bars while jumping or slow down when running through weave poles. Border Collies appear to be over-represented in studies of iliopsoas injuries, but this may be skewed by the high number of Border Collies involved in highly active sports, such as agility and disc-dog competitions.

Diagnosis

When your veterinarian examines and manipulates your dog’s leg, they may notice pain. Extension of the hip, especially if combined with internal rotation, generally causes a very painful reaction.

As is typical of all soft-tissue injuries, radiographs are not usually helpful for diagnosis. The one exception would be if a dog has a chronic injury with associated mineralization, where the tendon attaches to the femur. Computed tomography (CT) and magnetic resonance imaging (MRI) are superb techniques for the identification of iliopsoas problems, but they are expensive. Ultrasounds, in the hands of someone experienced at reading muscle and soft-tissue scans, can be wonderful for diagnosis, even differentiating acute versus chronic injuries.

Treatment

After your dog has been diagnosed with an iliopsoas injury, the hard work begins. As is typical of soft-tissue injuries, a complete rehabilitation plan is important. All dogs benefit from restricted exercise while trying to heal this type of injury. For an acute injury, complete rest may be necessary initially.

If your veterinarian says the iliopsoas injury is secondary to another problem, then that needs to be addressed. Common problems in these cases include a cruciate tear of the stifle, hip dysplasia, spinal deformities and other orthopedic problems. The rehabilitation and treatment of the main problem sometimes allows the iliopsoas injury to “cool off” and heal.

Plan on a rehabilitation program of 4-12 weeks for most dogs, although it can take longer, depending upon the injury itself. Previously injured dogs may benefit from a lifelong program to help prevent future and recurring problems. Exercise and activity will need to be restricted, at least initially. Food puzzles, snuffle mats, quiet scent games, and the use of chew toys and other items while crated can be invaluable.

Lasers are a good rehabilitation tool, and most dogs handle them well. Lasers help increase circulation to the injured area, which speeds healing. It is done on an out-patient basis, and no sedation or anesthesia is required. Magnetic field therapy is a good complement to this. At home, your rehab therapist can teach you massage techniques and a passive range of motion exercises to do. Always follow the directions exactly. Any changes could create more problems. Eventually, underwater treadmill and strengthening exercise may be added.

At home, you may be given exercises involving walking your dog backwards or practicing lateral steps. The use of cavalletti (a series of low jumps) may help build strength. Your dog will have a set schedule of increasing exercise, such as starting with short walks multiple times per day on leash. Walks will gradually lengthen in time but will be kept controlled on leash for a long time.

Muscle relaxants such as methocarbamol and nerve-pain medications such as gabapentin may be prescribed to keep your dog comfortable while healing. Even if they appear fine with these medications, your dog needs to follow their rehab restrictions, since the medications are masking the problem to a certain extent. Acupuncture can be used to help with pain control. Chronic strains may benefit from heat therapy and therapeutic ultrasound.

Once a dog is improving with at-home and clinical rehab programs, they can gradually return to their regular sport with some precautions. An older dog with multiple concurrent problems (such as hip dysplasia and iliopsoas injury) may need to switch to a quieter sport, like nose work, instead of returning to agility. If they return to active agility, they will need to build back up with very low, straight-line jumps, and slowly add height and turns. Weave poles should be added last.

If your dog continually injures their iliopsoas and never improves, surgical intervention may help to relieve pain. The surgery is called a tenectomy, and it involves cutting the tendon where it attaches to the femur. Most dogs will not go back to their former athletic status, but the tenectomy can relieve chronic pain.

Prevention

To help prevent iliopsoas injuries, do a consistent warm-up routine before starting any strenuous activity. This should consist of walking, jogging and maybe a few low jumps, followed by gentle stretches. Your dog should also have a cool down period after activity, which may include icing.

Iliopsoas injuries should always be evaluated carefully, with a look for concurrent problems. It may require referral to a sports medicine veterinary clinic for accurate diagnosis and the best care plan. All abnormalities need to be addressed. Rehabilitation for iliopsoas injuries is extensive. The program set out for your dog needs to be followed carefully and fully. Shortcuts will lead to re-injury.

Explore the videos in our Canine Health Minute series for more tips about how to keep your active dog safe from injury.

This article has been reprinted with permission from the Cornell University College of Veterinary Medicine’s DogWatch newsletter, published by Belvoir Media Group. When you become a member of the Riney Canine Health Center, you will receive a free subscription to DogWatch.