Iliopsoas Injury in Dogs: A Hidden Cause of Lameness

An iliopsoas injury in a dog can remain an overlooked cause of lameness for weeks because the muscle lies deep beside the lumbar region, pelvis, and inner femur. The iliopsoas unit, formed by the psoas major and iliacus muscles, flexes the hip and helps stabilize the lumbar spine. When its fibers or tendon are strained, a dog may continue bearing weight but shorten the stride and avoid specific movements.

The problem is often seen in sporting dogs, very active animals, and patients that slipped, splayed their hind limbs, or accelerated suddenly. It can also develop as a secondary injury. A dog limping because of a cranial cruciate ligament rupture, hip dysplasia, or lumbosacral pain changes how the limb is used and may overload the iliopsoas. In those cases, treating the muscle without recognizing the primary disorder increases the risk of recurrence.

Clinical signs vary. Some dogs become lame after exercise and appear normal after rest. Others resist jumping, getting into a car, running, or extending the hind limb backward. Pain may be noticed in the groin, although visible swelling is not always present. With chronic injury, owners may observe reduced performance, shorter steps, difficulty sitting symmetrically, and loss of thigh muscle mass.

During an orthopedic examination, combining hip extension with rotation of the limb can tension the iliopsoas and reproduce pain. The maneuver must be performed carefully because forcing an already painful joint can worsen discomfort. The veterinarian also assesses the stifle, hip, spine, and surrounding muscles for concurrent causes. Precise localization matters because low-back pain, hip disease, and iliopsoas injury can coexist.

Radiographs are useful for evaluating bones and joints, but normal radiographs do not rule out a muscle strain. Musculoskeletal ultrasound may reveal disruption of the fibers, edema, fibrosis, or lesions near the insertion on the lesser trochanter. Magnetic resonance imaging provides additional detail in selected cases. Imaging findings must be interpreted alongside the history and physical examination because minor asymmetries do not always explain the lameness.

Recovery usually requires temporarily reducing activities that stretch the muscle or demand explosive force. This does not mean every patient should remain completely inactive for an indefinite period. A plan may combine controlled walks, prescribed pain management, physical modalities, and progressive exercises. Veterinary rehabilitation can help restore mobility, core strength, and limb control without loading the tissue before it is ready.

Unsupervised stretching deserves caution. Strong hip extension can reopen healing fibers, especially early in recovery. Return to running, jumping, and play should be based on comfort, gait symmetry, and strength rather than the number of days that have passed. When muscle loss is present, gradual strengthening also limits compensation and protects other structures.

The prognosis is generally good for mild or moderate injuries that are correctly identified, although chronic cases may require more time and investigation for associated disease. If lameness repeatedly returns after exercise, the dog avoids extending a hind limb backward, or previous radiographs did not explain the problem, the iliopsoas should be considered. An individualized plan helps avoid too little rest, excessive rehabilitation, and a premature return to activity.

Bibliographic reference: Spinella, G.; Davoli, B.; Musella, V.; Dragone, L. Observational Study on Lameness Recovery in 10 Dogs Affected by Iliopsoas Injury and Submitted to a Physiotherapeutic Approach. Animals, v. 11, n. 2, 419, 2021. doi: 10.3390/ani11020419.

Bibliographic reference: Cannon, M. S.; Puchalski, S. M. Ultrasonographic evaluation of normal canine iliopsoas muscle. Veterinary Radiology & Ultrasound, v. 49, n. 4, p. 378-382, 2008. doi: 10.1111/j.1740-8261.2008.00385.x.