What is the iliopsoas?
The iliopsoas is a combination of two muscles that fuse together: the psoas and iliacus. These muscles run from the underside of the lumbar vertebrae (lower spine) and the wing of the pelvis to the lesser trochanter – a bony projection on the inside of the upper thigh bone (femur). Its main job is to flex the hip, bringing the hindleg forward, but it also flexes the lumbar spine (lower back) and helps stabilize the core of the body.
How can the iliopsoas become injured?
An iliopsoas injury can occur due to trauma, but it is usually caused by overuse and overextension (straightening of the hindlimb) or a combination of the two – intense contraction while the hip is extended.
Working dogs and dogs that participate in high intensity sport like flyball or agility are predisposed to acute/sudden iliopsoas injury. Slipping, causing a sudden outwards splaying of the hindlimbs, can also case acute injury, so ice, hardwood, tile, and other slippery surfaces can increase your pet's risk of an iliopsoas injury.
Most cases of iliopsoas pain are not due to injury but result from pain when extending the hip. The most common conditions that cause pain with hip extension are hip arthritis and cranial cruciate ligament disease. To avoid hip extension (and pain), the dog will be constantly working the iliopsoas muscle, leading to overuse and pain.
"Most cases of iliopsoas pain are not due to injury but result from pain when extending the hip."
Over time, the muscle will shorten (called adaptive shortening) and when the hip tries to extend past a certain point, either when walking or when your veterinarian assesses the dog’s range of motion, the muscle will become reactive and painful. This causes a negative cycle of pain with hip extension, iliopsoas muscle overwork, and subsequent soreness.
Dogs who are overweight put constant strain on their iliopsoas causing chronic strains that can be subtle to notice. Older animals are also more prone to iliopsoas injury because of reduced flexibility and muscle strength attributable to age.
What are the signs of iliopsoas injury?
Signs that your dog has a painful iliopsoas can include:
- reduced performance (if a sporting dog)
- very subtle weight-shifting away from the affected side when standing
- an obvious limp
How is iliopsoas injury diagnosed?
Your vet may notice that your dog resists or has pain when their hip is extended. Your veterinarian can also detect a painful response when they palpate the iliopsoas muscle. X-rays (radiographs) sometimes show changes on the thigh bone (femur) where the muscle attaches; however, these changes aren’t necessarily diagnostic as they could reflect a past injury. More advanced imaging techniques such as ultrasound, CT or MRI are needed to make a definitive diagnosis of iliopsoas injury.
How are iliopsoas injuries treated?
The initial treatment for acute iliopsoas injuries is activity restriction and pain control for 10-14 days. Dogs must avoid high-impact activity and any situations in which they could slip and fall. Pain control may include cold therapy in the first few days, anti-inflammatory medications, muscle relaxants, gabapentin, and opioids. Stretching should not be encouraged because there is a risk of causing microtears in the tissue.
How can rehabilitation help iliopsoas injuries?
Formal rehabilitation can be started shortly after injury to help your dog regain normal mobility more quickly. As an iliopsoas injury is a soft tissue strain, healing can take a long time and the area is susceptible to re-injury, especially if your dog attempts to do something the muscle/tendon isn’t prepared for.
"Always follow your veterinary rehabilitation therapist’s instructions and don’t push for more activity until they deem it safe."
In the first few weeks, rehabilitation must be gentle with gradual progression to more advanced work. Passive range of motion (PROM) and static stabilization exercises that strengthen core muscles can be initiated once pain is controlled. With guidance from your pet’s rehabilitation therapist, these exercises can progress to more active range of motion and strengthening exercises, like cavaletti pole. They will also give you instruction on exercises your dog may perform at home, like hill walking. Always follow your veterinary rehabilitation therapist’s instructions and don’t push for more activity until they deem it safe. If your dog ever seems sore, inform their therapist right away so the rehabilitation plan can be modified.
If iliopsoas pain is chronic or secondary to another condition, then rehabilitation is also warranted and often follows the same pattern as rehabilitation for acute injury.
Modalities used for iliopsoas strain rehabilitation include photobiomodulation (laser therapy) and therapeutic ultrasound, which both help improve healing. Shockwave may also be used to promote healing. Land and underwater treadmill can be used at the appropriate stage of healing to strengthen the muscles of the hip and core. Swimming may not be recommended as it risks aggravating the injury.
Acupuncture can be used to reduce painful trigger points in the muscle and surrounding tissues. Regenerative medicine, the use of platelet rich plasma (PRP) or stem cells in an identified muscular lesion, may also be used, especially in dogs who aren’t responding to rehabilitation.
Does my dog need surgery?
When a dog doesn’t respond to pain management and rehabilitation, including treatment of any underlying condition, surgery may be considered. This more commonly occurs when there is excess scar tissue that limits movement and flexibility of the muscle.
When will my dog recover?
As soft tissue injuries are unpredictable, an exact timeframe for recovery isn’t known. If acute, iliopsoas injury recovery can take three to nine months or longer with rehabilitation therapy. When injury occurs secondary to an underlying condition, recovery may be faster, but the issue may be more likely to recur, especially if the predisposing condition cannot be resolved.
As with any soft tissue injury, it is important to slowly return to normal training and to always properly warm up the area before exercise, with a stretch and cool down period afterwards that may include cold therapy.
