Iliopsoas Tendinopathy

Original Editor - Shejza Mino

Top Contributors - Shejza Mino, Lucinda hampton, Kim Jackson, Wendy Snyders, Leana Louw and Rishika Babburu  

This article is currently under review and may not be up to date. Please come back soon to see the finished work! (23/09/2020)

This article is currently under review and may not be up to date. Please come back soon to see the finished work! (23/09/2020)

Introduction

The iliopsoas muscle is a strong hip flexor, playing a significant role in general hip strength and function. Pathologic conditions of the iliopsoas have been shown to be significant cause of hip pain and dysfunction, ranging from asymptomatic snapping hip syndrome to symptomatic irritation of the tendon and related bursa . Additionally, iliopsoas disorders have been associated with lumbopelvic disorders such as low back pain and gluteal pain, groin pain particularly in the athletic population, even anterior thigh and knee pain.

Excessive tightness of the iliopsoas muscle may cause increased friction, or result in an audible snap, when the tendon travels over the underlying bony landmarks. These landmarks include the anterior inferior iliac spine, iliopectineal eminence, bony ridge of the lesser trochanter or the anterior capsule of the femoral head, This condition is known as "asymptomatic internal snapping hip syndrome" when painless. However, when pain/dysfunction is experienced with the audible snap, there are various terms used to describe the condition including "painful internal snapping hip, internal coxa saltans, iliopsoas tendinitis, iliopsoas tendinosis, iliopsoas tendinopathy, iliopsoas bursitis, or iliopsoas syndrome". Due to the close proximity of the Iliopsoas tendon and the related bursa, inflammation of one of these structures inevitably causes inflammation of the other. Therefore, the literature reports that a diagnoses of iliopsoas tendinitis and iliopsoas bursitis are synonymous, as the clinical presentation, evaluation, and management are nearly identical.

The term Iliopsoas tendonitis is often used and implies inflammation of the tendon or area surrounding the tendon. Studies have revealed the presence of inflammation in the acute phase however, chronic tendon pathologies lack an inflammatory process and are instead characterized by a failed healing response and tendon degeneration. For this reason, it is arguably more accurate to classify this condition as a tendinopathy when referring to it generally.

Clinically Relevant Anatomy

The iliopsoas refers to the combined iliacus and psoas muscles. The two muscles are commonly separate entities in the abdomen and merge together in the thigh.

The origin of the deep fibers of the psoas major is at the transverse process of the T12 to L5 vertebrae. The superficial fibers originate from the outer surfaces of lumbar vertebra and adjacent intervertebral discs. The origin of the iliacus muscle is in the iliac fossa of the pelvis.

The psoas major and illiacus muscles merge between L5-S2. The iliopsoas runs from the pelvis to the thigh under the inguinal ligament and the tendon travels anteriorly across the acetabulum between the anterior inferior iliac spine (laterally) and the iliopectineal eminenence (medially) to eventually attach onto the lesser trochanter of the femur. The iliopsoas bursa is located between the iliopsoas musculotendionous junction and the underlying bony pelvis. The bursa has been reported to communicate with the hip joint in ~15% of the adult population.

Nerve supply:

• The iliacus component of the iliopsoas muscle is innervated by the femoral nerve (composed of anterior rami of L2-L4)
• The psoas component of the iliopsoas muscle is innervated by direct branches of the lumbar plexus (anterior rami of L1-L3)

Vascular supply:

• Iliolumbar artery & medial femoral circumflex artery.

Function:

• Flexion & external rotation of the hip

Epidemiology

In general, iliopsoas pathologic conditions (including tendinitis, bursitis, snapping and impingement) have been deemed to be the main cause of chronic groin pain in roughly 12-36% of athletes and in 25-30% of athletes with acute injury to the groin region

Data on the prevalence of iliopsoas tendonitis remains unknown however, it more commonly affects young adults and is mildly more prevalent in females

Etiology

The two most common causes of irritation to the iliopsoas tendon is acute injury and overuse injury from repetitive microtrauma:

• Acute injuries typically result from either eccentric contraction of the muscle or brisk flexion against an extension force that surpasses the capacity of the tendon. Less commonly, acute musculotendinous  injuries to the iliopsoas is caused by traumatic event.
• Overuse injuries may result from any activity requiring repetitive hip flexion or repetitive external rotation of the hip. Chronic injuries in any tendinopathy occur when the body's ability to repair itself is exceeded by repetitive micro trauma.

Other reported causes:

• Commonly, psoas tendinopathy occur secondary to repetitive flexion of a hip that is in external rotation. The condition is commony referred to as "dancer's hip" or jumper's hip", as associated movements are a predisposing factor to injury.
  • More than 90% of ballet dancers reporting an audible click, pop or snap in the hip.
• Individuals who participate in rowing, track and field, uphill running, soccer, gymnastics, hurdling and resistance training may be at increased risk of a psoas tendionpathy injury.
• Adolescents during growth spurts have relatively decreased flexibility of the hip flexors, potentially putting them at greater risk.
• Rheumatoid arthritis has been reported as a cause of Iliopsoas bursitis (closely associated to iliopsoas tendinitis).

Clinical Presentation

The clinical presentation of symptomatic iliopsoas tendionopathy often encompasses a palpable and audible snap that results from flexion and extension of the hip. Persistent irritation of the tendon may result in inflammation to either the tendon, underlying bursa or both. Chronic irritation will not be associated with inflammation but will instead demonstrate painful degeneration and fibrosis of the tendon,

History

A history of insidious deep groin or anterior hip pain is common. Initially, pain is provoked with onset of aggravating activity, decreasing shortly after. Symptoms may progress to constant pain during activity that diminishes only with rest and lastly, to the presence of pain with both activity and rest. The diagnosis is usually delayed, with the average time between initial symptoms and diagnosis is estimated to be between 32-41 months.

• Patients may report pain with activities such as running or kicking. Additionally, tying shoe laces, rising from a seated position after prolonged sitting and inclined walking are some other examples activities of daily living that may provoke symptoms.
• Radicular symptoms along the anterior thigh down towards the knee may be reported.
• Commonly, an audible click or snap coming from the groin or hip area is reported. This is associated with internal snapping hip syndrome, a condition where the tendon of the iliopsoas muscle glides over the head of the femur, or over the iliopsoas bursa causing an audible snap that can usually be palpated.
• A tight iliopsoas muscle may cause symptoms over the anterior knee that resembles patellofemoral dysfunction.
• Dysfunction of the psoas muscle is commonly associated with various complaints to the lumbosacral region, which may include low back pain, discomfort into the gluteal or thigh region and the inability to stand fully erect,

Physical Examination

Observation:

• Signs of psoas hypertonicity such as holding the affected hip in a mildly flexed and externally rotated position, as well as anterior pelvic tilt.
• Gait: A shortened stride length may be obvious on the affected side. Additionally, increased knee flexion may be observed during heel strike and midstance phases.

Palpation:

• Increased tenderness with deep palpation of the iliopsoas muscultendionous junction within the femoral triangle. Palpation of the inguinal lymph nodes in this region should be unremarkable.
• With the patient in a prone position, the insertion of the iliopsoas tendon onto the lesser trochanter can be palpated under the gluteal fold, which may reveal pain.

Range of Motion:

• Passive hip extension (normal ~15 degrees) may be limited and/or elicit pain.
• Active or resisted hip flexion may reproduce pain.

Functional/Orthopedic testing:

• Thomas test or Modified Thomas test - can help identify excessive hypertonicity in the hip flexors
• "Iliopsoas test": Resisted hip flexion, with the hip in external rotation (performed with patient in a supine position). Any weakness and/or pain symptoms is a positive test.
• Ludloff's sign (Isolated strength muscle assessment of the iliopsoas): In a seated position with the knees extended, the patient is asked to lift the heel of the affected side off the table. Considered positive if pain is produced or weakness revealed.
• Stinchfield test: Patient performs an active straight leg raise (SLR) to 45 degrees. Then, ask patient to resist as downwards force is applied to anterior thigh. Pain and/or weakness suggests involvement of the psoas muscle or intraarticular pathology.
• Snapping hip maneuver: To begin, the affected hip is positioned in a flexed, abducted and external rotated position. The hip is passively moved into extension and internal rotation. Positive test is a palpable or audible snapping located in the inguinal regiokn. Pain provoked with this maneuver suggests iliopsoas tendinitis or bursitis.

Psoas hypertonicity may result in reciprocal inhibition of antagonist muscles and dysfunctions along the kinetic chain. Additionally screening should include signs of hip abductor weakness, spinal instability, lower cross syndrome, increased foot pronation as well as dysfunctional breathing.

Differential Diagnoses

• Tendon avulsion
• Muscle Contusion
• Femoral Acetabular Impingement (FAI)
• Avascular necrosis of the femoral head
• Stress fracture of the femoral neck
• Groin injury
• Femoral tendinitis and bursitis
• Hip osteoarthritis
• Labral tear
• Hip fracture
• Legg-Calve Perthes Disease
• Lumbosacral Disc Injuries
• Lumbosacral Radiculopathy
• Osteitis Pubis
• Slipped Capital Femoral Epiphysis (SCFE)
• Snapping Hip Syndrome
  • "Internal" snapping hip, like previously mentioned, is related to the iliopsoas tendon.
  • "External" snapping hip is related to either the iliotibial band or gluteus maximus tendon traveling over the greater trochanter
  • "Intraarticular" snapping hip can be due to loose bodies, labral tears or recurrent dislocation.

Workup

Laboratory Analysis

• Laboratory studies, only indicated if the diagnosis is unclear, may include a CBC count, erythrocyte sedimentation rate or C-reactive protein, rheumatoid factor, anticyclic citrullinated peptide antibody, antinuclear antibody, and urinalysis. These tests are useful when considering pathology to the abdomen and pelvis that may present as groin pain such as colon cancer, diverticulitis, prostatitis, salpingitis, renal calculi, appendicitis and psoas abscess,

Medical Imaging

• Radiography
  • Typically not indicated for soft-tissue disorders and findings are unremarkable in cases of iliotendonitis however, radiographs may be used as an initial imaging study if other bony pathology is suspected or in the presence of "red flags".
  • Slipped capital femoral epiphysis should be ruled out in a child or adolescent presenting with hip pain.
• Ultrasonography
  • Diagnostic ultrasound (US) is a noninvasive and easily accessibly option to evaluate muscle-tendon injuries. Findings typically reveal a thickened tendon.
  • Iliopsoas bursitis is associated with an excessive amount of fluid in the iliopsoas bursa, which is usually visualized on US.
  • Not always optimal test for diagnostic accuracy as this imaging choice is highly user-dependent.
• Magnetic Resonance Imaging (MRI)
  • Currently, MRI is the "criterion standard" when evaluating symptoms relating to the hip and pelvis.
  • Provides the most accurate assessment of the iliopsoas tendon and bursa.
  • Study of 19 endurance athletes that presented with groin pain and were given a diagosis. After MRI, 32% of the groin pain cases were rediagnosed to a different etiology. The diagnoses included iliopsoas muscle tears and iliopsoas tendinitis.
  • MRI findings when evaluating musculotendinous injuries:
    • Spin-echo T2-weighted images will show increased signal intensity that is associated with swelling and inflammation. A musculotendinous injury of greater severity with associated hemmorhage will display high-signal intensity with both the T1-weighted images and T2-weighted images.
    • Peritendinitis evaluation - the peritendinous tissue will display increased fluid that is detected on the spin-echo T2-weighted images or short T1 inversion recovery (STIR) sequence as a focus of high-signal intensity surrounding a normal tendon.
    • Tendinosis - the spin-echo T1-weighted images will demonstrate increased signal intensity within the tendon that is associated with myxoid degeneration or angiofibroblastic proliferation. The spin-echo T2-weighted images may show an abnormal signal (usually less than that seen on the T1-weighted images) or a normal signal.

Lidocaine Injection

• A "lidocaine challenge test" involves either an interventional radiologist or an orthopedic surgeon administering a lidocaine injection to the iliopsoas tendon via the anterior aspect of the femoral triangle (under US guidance). If pain relief is achieved after the injection, a diagnosis of iliopsoas tendonitis is confirmed.

Management

Conservative management

• Conservative management of psoas tendinopathy supports relative-rest, activity modification as well as exercise. (C)
• Soft tissue techniques such as myofascial release may be useful to assist in decreasing muscle tightness and overall having a neuromodulatory effect.
• Joint mobilization and/or manipulation can assist in restoring lumbopelvic joint mobility.
• Range of motion, stretching and strengthening exercises should target the hip flexors and antagonistic muscle groups.

Rehabilitation

• Acute Phase
  • The main objective of the first phase is to decrease pain symptoms, reduce muscle spasm and decrease any swelling. If the patient has stopped engaging in activities of daily living, getting the patient back to these activities is also an important goal of this first phase.
  • Acute rehabilitation phase includes relative rest (avoiding any pain-provoking activities), ice, medication and light stretching.
    • Ice: Apply for 20-minutes, every few hours for the first 1-3 days
    • Medication: Short-term course of non-steroidal anti-inflammatory drugs (NSAIDs)
    • Gentle stretching will aid in reducing muscle spasm. To avoid over stretching, do not stretch soon-after a period of icing as icing may increase the individuals pain threshold, making them less sensitive to pain.
    • The chosen iliopsoas stretch is held for 20-seconds, followed by 30-seconds of rest, and repeated five times. The stretch should remain pain-free at all times and the patient should bring their awareness to taking dull, deep breaths while holding the stretch.
• Recovery Phase
  • The primary goal of the second phase is to restore range of motion (ROM), strength, endurance and proprioception. Eventually, sport-specific activity is included.
  • ROM:
    • Stretching routine for the iliopsoas complex is continued and engaging in proper warm-up and cool-down with exercise is emphasized.
  • Injury to the iliopsoas muscle may be associated with increased lumbar lordosis and anterior pelvic tilt. Achieving neutral postural can be worked on by both stretching and strengthening the appropriate muscle groups:
    • Stretching:
      • Stretching the rectus femoris helps to bring an anteriorly-rotated pelvis into a more neutral position. Doing so will take tension off of the iliopsoas muscle, decreasing the likelihood of strain or spasm.
      • All stretches in this phase are held as described in the acute phase (hold for 20-seconds, relax for 30-seconds, repeat 5x
    • Strengthening:
      • Increasing strength of the hamstring muscle group will increase the posterior force on the pelvis, decreasing the stress of the iliopsoas pulling on the pelvis anteriorly.
      • Abdominal strengthening exercises should be performed with knees and hips flexed to 90 degrees will allow the iliopsoas to relax and the pelvis to remain in neutral.
      • Gluteus maximus strengthening also plays a role in achieving a neutral position of the pelvis.
      • Strengthening exercises are performed daily (4 sets of 10 to 15 repetitions).
    • Endurance training:
      • Improved muscular endurance of the iliopsoas can be achieved overtime with repetitive movements (hip flexion or external rotation of the femur) performed at a low resistance. Some examples include cycling, walking, machine stair climbing.
      • Endurance exercises should result in no pain, and there should be sufficient periods of rest between endurance training sessions. Eventually, the individual should work up to performing endurance sessions daily, gradually increasing the duration of activity.
• Maintenance Phase
  • This phase focuses on challenging the muscles to perform.
  • Continue stretching the iliopsoas and rectus femoris muscles.
  • Gradually increase resistance used with strengthening exerices (i.e., seated iliopsoas strengthening with ankle weight, supine hip flexion (straight leg raise) with ankle weight, seated external rotation strengthening with ankle weight, seated external rotation with resistance band)
  • Advancing strengthening exercises for the iliopsoas and the hamstrings - gradually progressing resistance can be achieved by either increasing the number of repetitions performed or increasing the weight, as tolerated by the individual.
    • i.e., Standing hip flexion (machine), prone and seated hamstring curls (machine), advanced lunges with step-up (lunges are performed at a slower pace ensuring smooth and controlled rhythm).
• Return to Sport (RTS)
  • The patient should be asymptomatic, or able to tolerate pain before considering RTS.
  • Range of motion, flexibility and strength of the hip flexors and antagonist muscles should be restored to the level of the contralateral side.
  • Sport-specific activities/drills should be relatively pain-free.

Surgical Intervention

• Surgical intervention is only considered when minimal improvement in the condition is achieved with a prolonged trial of nonoperative management.
• There are two surgical techniques reported in the literature which include either a complete or partial release of the iliopsoas tendon. Generally, good outcomes have been reported with both procedures, including decreased pain and with no significant residual weakness.

Other

• Peritendinous corticosteroid injection
  • The injection consists of a local anesthetic that is combined with a corticosteroid.
  • One study evaluated patient-outcomes after injection into the iliopsoas bursa in a case suspecting tendinopathy to the iliopsoas muscle. The results demonstrated relevant improvement at 1-month post-injection. Additionally, the study reported that most patient experienced a notable decrease in pain 15-minutes after the injection was performed.

Resources

• Psoas major
• Snapping Hip Syndrome
• Iliopsoas Bursitis