Psoas syndrome results from dysfunction of the iliopsoas muscle and causes a constellation of symptoms, including low back pain, groin pain, pelvic pain, or buttock pain. The primary action of the iliopsoas muscle is hip flexion. Therefore, back pain may occur with standing, walking, or changing of position from sitting to standing.[1] The associated buttock pain is often on the contralateral side and can radiate down to the knee. When the iliopsoas tendon passes over a bony prominence, it can cause rubbing at these points that produce a “pop” or “snap,” leading to a condition called Coxa Saltans or snapping hip.[2] However, psoas syndrome can occur independently of snapping hip. 

Psoas syndrome is commonly seen in athletes, especially jumpers, dancers, and runners, and is among the most common causes of groin pain in this group.[3] However, psoas syndrome can occur in non-athletes as a result of overuse, given its function as a hip flexor and external rotator of the leg. Treatment typically consists of conservative measures such as activity modification, physical therapy, manual therapy, NSAIDs, and corticosteroid injections.  If conservative measures do not relieve symptoms, surgical iliopsoas release can be a consideration.[4]

This procedure review focuses on the use of osteopathic manipulative treatment (OMT) in the treatment of iliopsoas dysfunction. The two specific osteopathic manipulative treatment modalities for the iliopsoas that will be discussed are muscle energy treatment (MET) and counterstrain (CS).

MET is a direct technique where the muscle or joint is taken into a restrictive barrier and asked to provide an isometric muscle contraction against the provider.[5] Following the isometric contraction, the muscle is relaxed, and the provider takes the dysfunction further into the restrictive barrier. The most common MET protocol, and the one described here, uses three to five repetitions of isometric contraction followed by relaxation.

CS is an indirect technique where a tenderpoint is localized and moved into a position of ease for 90 seconds while monitoring for the reduction of pain and change in the texture of the tenderpoint. The muscle or joint returns to a neutral position, and the tenderpoint released, resulting in a decrease in hypersensitivity and proprioceptive activity.[6]

The anatomy of the iliopsoas is critical in understanding its role in psoas syndrome and the proper technique of MET and CS treatment of iliopsoas dysfunction. The iliopsoas divides into two parts: 1) the psoas (major and minor) muscle and 2) iliacus muscle. The psoas major originates at the T12 through L5 vertebrae and inserts on the lesser trochanter of the femur. The psoas minor originates at the T12 to L1 vertebrae and inserts at the iliopubic eminence. The iliacus muscle originates within the iliac fossa/sacral ala and inserts at the lesser trochanter of the femur.[7] 

The psoas major and minor muscles receive innervation of the L1-3 branches of the lumbar plexus, while the iliacus receives innervation from the femoral nerve.[7] The psoas and the iliacus muscle fibers pass deep to the inguinal ligament and merge to insert on the less trochanter of the femur. The iliopsoas is primarily responsible for hip flexion, but also aids in external rotation of the leg and may also act as a stabilizer of the spine during hip flexion. A study done by Hu et al. found that with hip flexion, the contralateral psoas muscle was activated and is likely involved in spine stabilization.[8]

OMT is used in the treatment of iliopsoas somatic dysfunctions to decrease pain, improve range of motion, and restore neuromusculoskeletal function.

There are several proposed mechanisms for MET, but the two commonly accepted principles are 1) post-isometric relaxation and 2) reciprocal inhibition. Both principles take advantage of the proprioceptive mechanisms within muscle fibers and joints, including the alpha motor neuron and Golgi tendon organ. Post-isometric relaxation is based on the theory that the muscle enters a refractory period following isometric contraction. During this refractory period, there is reduced muscle tone, which allows the muscle to be taken further into the restrictive barrier. Reciprocal inhibition hypothesizes that there is a period of antagonist muscle relaxation following contraction of the agonist muscle, which allows the muscle to be taken further into the restrictive barrier.[5] 

CS tenderpoints form as a result of injury or dysfunction of the muscle resulting in altered proprioception and hyperactivity of the affected muscle. During CS, the muscle becomes passively shortened to allow for resetting of the Golgi tendon and returning the muscle to its proper length and alignment.[6]

Before initiating OMT, a somatic dysfunction should be present. Somatic dysfunction is a change in joint or muscle function or architecture. Somatic dysfunction describes tissue texture changes, asymmetry, restriction of motion, and tenderness. Examples of possible somatic dysfunctions of the iliopsoas include hypertonic tissue texture, restriction in hip extension, and tenderness of the iliopsoas.  Patients who would benefit from MET or CS treatments may also present with symptoms of psoas syndrome, as described above.

The choice of MET or CS as a treatment modality is dependent upon the patient’s status and physician preference. CS is a passive treatment that involves monitoring the psoas, shortening the muscle into a position of ease, and holding this position for an extended period. CS is appropriate for a patient in extreme discomfort or someone unable to produce a coordinated muscle contraction. MET is an active treatment that requires the patient to provide a voluntary isometric muscle contraction against the physician, followed by muscle relaxation during which the physician will take the dysfunction further into the restrictive barrier. During both techniques, the patient must be able to provide feedback to the physician. 

Contraindications to MET include:

• Fracture in the affected area
• Unstable pelvis or hip joint
• Recent surgery, or low energy.[9]
• Inability to provide isometric contraction of the affected area
• Inability to follow directions

Contraindications to CS include:

• Inability to voluntarily relax
• Inability to provide feedback to the physician
• Fracture in the affected area
• Torn ligament or tendon in the affected area [9]

The only required equipment for this procedure is a firm OMT or massage table.