Hip Flexor Tendonitis

Other Names

• Iliopsoas Tendinopathy
• Iliopsoas Bursitis
• Iliopectineal Bursitis
• Medial snapping hip syndrome
• Iliopsoas strain

Pathophysiology

• General
  • Due to repetitive hip flexion and external rotation
• Bursitis vs tendinitis
  • Note that iliopsoas bursitis and iliopsoas tendinitis are discrete entities
  • However, interrelated inflammation of one leads to inflammation of the other
  • Clinically, they present the same and thus are indistinguishable
• Biomechanics
  • During the stance phase when running, the hip is extending
  • The iliopsoas contracts eccentrically, decelerating the hip
  • Gains potential energy as it elongates
  • Energy is then released during the swing phase as the ipsilateral limb comes forward

Causes

• Acute trauma
  • Less common
• Overuse injury
  • Likely due to repetitive hip trauma as the result of flexion and extension
  • Maybe in part due to sudden hyperextension of a flexed hip, stretching the iliopsoas muscle and bursa
  • Another hypothesis is a flexed, abducted, and externally rotated hip causes the muscle and bursa to snap over the femoral head and joint capsule
  • An enlarged bursa is more commonly seen in individuals with hip-related symptoms and not overuse injuries
  • The tendon may also rub against the pubic iliopectineal eminence
• Rheumatoid Arthritis (RA)
  • Although joints are classically involved in RA, tynosynovium, and bursa may be affected
  • Associated with RA affecting the Hip Joint, less commonly in isolation of the bursa
  • Approximately 14% – 30% of iliopsoas bursa communicate with the hip joint

Pathoanatomy

• Iliopsoas
  • Composed of Iliac, Psoas Major, and Psoas Minor
  • The function is primarily hip flexion, to a lesser degree external rotation
  • Mscle passes anterior to the pelvic brim and hip capsule in a groove between the anterior inferior iliac spine laterally and iliopectineal eminence medially
  • Iliopsoas Bursa sits inferior to these muscles and above the joint capsule of the Hip Joint

Associated Pathology

• Rheumatoid Arthritis
• Snapping Hip Syndrome
• Hip Osteoarthritis
• Sports
  • Dancing
  • Ballet
  • Resistance training
  • Cycling
  • Rowing
  • Running (particularly uphill)
  • Track and field, especially hurdling
  • Soccer
  • Gymnastics
• History of Total Hip Replacement
• Rheumatoid Arthritis

Differential Diagnosis

• Fractures And Dislocations
  • Pelvic Fracture
  • Hip Fracture
  • Acetabular Fracture
  • Femoral Neck Stress Fracture
  • Pelvic Stress Fracture
  • Hip Dislocation

• Arthropathies
  • Osteitis Pubis
  • Avascular Necrosis of the Hip
  • Hip Osteoarthritis
  • Femoroacetabular Impingement
  • Transient Osteoporosis of the Hip

• Muscle and Tendon Injuries
  • Hip Flexor Tendonitis
  • Piriformis Syndrome
  • Hamstring Strain
  • Proximal Hamstring Tendinopathy
  • Adductor Strain
  • Greater Trochanteric Pain Syndrome

• Bursopathies
  • Iliopsoas Bursitis
  • Ischial Bursitis

• Ligament Injuries
  • Acetabular Labrum Tear

• Neuropathies
  • Meralgia Paresthetica

• Other
  • Snapping Hip Syndrome
  • Septic Arthritis
  • Gout
  • Leg Length Discrepancy
• Pediatric Pathology
  • Transient Synovitis of the Hip
  • Developmental Dysplasia of the Hip (DDH)
  • Legg-Calve-Perthes Disease
  • Slipped Capital Femoral Epiphysis (SCFE)
  • Avulsion Fractures of the Ilium (Iliac Crest, ASIS, AIIS)
  • Ischial Tuberostiy Avulsion Fracture
  • Avulsion Fractures of the Trochanters (Greater, Lesser)
  • Apophysitis of the Ilium (Iliac Crest, ASIS, AIIS)

Diagnosis

• History
  • Pain may be insidious or acute
  • Located on the anterior hip but sometimes less focal or at deep to the groin
  • Often worse during exercise and immediately following
  • Initially, pain-free at rest may develop pain even at rest
  • May or may not have a snapping sensation, which is more common in the athletic population
  • Often worse with sitting for a long period of time, walking upstairs, jogging, running and kicking
  • The pain may radiate down the thigh towards the knee
• Physical Exam
  • An inguinal mass suggests an enlarged bursa, usually in more chronic presentations
  • Tenderness to palpation distal to the inguinal ligament, lateral to the femoral triangle, medial to Sartorius is considered pathognomonic
  • There may be weak resisted external rotation
  • Pain with resisted hip flexion
  • Pain with exaggerated passive hip extension
• Special Tests
  • Thomas Test: Ipsilateral limb is flexed to chest, the contralateral limb is brought into extension
  • Modified Thomas Test: Same as Thomas test, except contralateral limb allowed to hang off the table
  • Snapping Hip Sign: extension of their flexed, abducted, and externally rotated hip (needs to be updated)
  • Pelvifemoral Angle: measure angle of pelvis to hip flexor
  • Elys Test: prone, passively flex the knee to buttocks
  • Rectus Femoris Contracture Test: knee to chest, observe the contralateral limb
  • Prone Hip Extension Test: prone, extend affected hip, measure horizontal thigh angle

Radiographs

• Standard Hip Radiographs
  • The screening tool, typically normal
• Can consider arthrography, biography although these have fallen out of favor for MRI

Ultrasound

• May demonstrate
  • Well defined, thin-walled fluid collection along the iliopsoas tendon^[7]
• Can be used to guide a needle for diagnostic or therapeutic purposes
  • Target is just inferior to the iliopsoas muscle-tendon junction

MRI

• Findings
  • Distended bursa
  • Peritendinous fluid
  • Can demonstrate communication between bursa and hip joint

Treatment

Nonoperative

• Relative rest
• Physical Therapy
  • Emphasis on eccentric exercises
  • Stretching involving hip extension for 6-8 weeks in alleviating symptoms^[8]
• Pharmacotherapy
  • NSAIDS
• Corticosteroid Injection

Operative

• Indications
• Technique
  • Tenotomy
  • Tendon lengthening