What are the common causes of right iliopsoas muscle injury?

Common Causes of Right Iliopsoas Muscle Injury

The right iliopsoas muscle is most commonly injured through acute trauma (high-speed blunt injury, pelvic/hip fractures), repetitive overuse from athletic activities (especially hip flexion exercises), iatrogenic causes (hip surgery, childbirth), or avulsion fractures at the lesser trochanter attachment site. 1

Traumatic Mechanisms

High-Energy Blunt Trauma

• High-speed blunt injury associated with pelvic or hip fractures and dislocations represents a major cause of iliopsoas injury, though these are less common than brachial plexus injuries due to the protective strength of the bony pelvis 1
• Injuries are most commonly stretching injuries or nerve compression from adjacent hematoma or fracture, and less commonly complete muscle rupture 1
• Lumbar spinal fractures can also cause indirect iliopsoas trauma through associated soft tissue injury 1

Avulsion Injuries

• Avulsion fractures at the lesser trochanter (where iliopsoas inserts) can occur from forceful hip flexion, causing traumatic edema, hematoma, or inflammation that compresses adjacent nerves 1
• These avulsions are described mainly in nonathletes and older individuals, frequently with no clear triggering event 2
• When avulsions occur without trauma in older patients, underlying pathology such as tumor or metastases must be ruled out 2

Overuse and Athletic Injuries

Repetitive Hip Flexion Activities

• Inadequate or excessive exercise involving repetitive hip flexion is a well-documented cause of iliopsoas injury 3
• Specific high-risk activities include supine double leg lifts, which can cause muscle tears with blood between muscle fibers 3
• The iliopsoas functions as the primary hip flexor, making it vulnerable during activities requiring repeated or forceful hip flexion 4

Endurance Athletes

• Elite endurance athletes, particularly cyclists, can develop iliopsoas-related symptoms through repeated mechanical trauma from a hypertrophied psoas muscle during hip flexion 1
• This mechanism involves arterial kinking and vasospasm rather than direct muscle injury, but represents an important athletic injury pattern 1

Iatrogenic Causes

Surgical Complications

• Iatrogenic injury to the iliopsoas can occur after total hip arthroplasty, gynecologic surgery, or genitourinary surgery 1
• Childbirth represents another iatrogenic risk factor for iliopsoas injury 1
• These injuries typically result from direct surgical trauma or postoperative hematoma formation 1

Pathophysiology of Injury

Muscle Strain and Tear

• The iliopsoas is relatively hypovascular in certain regions, which may predispose it to hypoxic degeneration and injury 1
• Traumatic iliacus muscle injury can produce a hematoma with potential femoral nerve neuropathy due to the anatomical proximity 3
• The injury typically presents with intense pain in the buttock, groin, and iliac fossa, with inability for hip flexion and ambulation 3

Tendon Attachment Pathology

• Chronic mechanical stress at the iliopsoas tendon attachment can trigger enthesitis and periostitis, leading to heterotopic ossification at the lesser trochanter 5
• This represents a distinct pathologic response involving actual bone formation at the attachment site, different from simple tendinosis 5
• The process involves bone proliferation at the cortical bone where the tendon attaches, occurring as a hallmark response to chronic mechanical stress 5

Clinical Presentation Patterns

Acute Injury Signs

• Discomfort on hip hyperextension is a key finding on physical examination 6
• Palpation and stretching of the affected muscle by simultaneous internal rotation and extension of the hip joint elicits pain 6
• Positive Thomas maneuver and reduced quadriceps strength (3/5) may indicate associated femoral nerve involvement 3
• Paresthesia in the femoral nerve territory suggests nerve compression from hematoma 3

Important Clinical Pitfall

• Plain radiographs are often normal in acute iliopsoas muscle injuries, making MRI or ultrasound essential for diagnosis 3, 6
• Ultrasonography can confirm the diagnosis and provide information about the location and extent of injury when radiographs are negative 6
• MRI demonstrates muscle tears with blood between fibers and is highly sensitive for detecting iliopsoas pathology 3, 7