Femoral Neuropathy

Other Names

• Femoral neuropathy
• Femoral nerve lesion
• Femoral nerve palsy
• Femoral nerve dysfunction
• Neuropathy of the femoral nerve
• Femoral neuritis
• Quadriceps weakness due to femoral nerve injury
• Femoral Nerve Injury
• Femoral mononeuropathy

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Background

• This page refers to neuropathies of the Femoral Nerve

History

• Unknown

Epidemiology

• Femoral neuropathy acocunts for 1% for all mononeurpathies (need citation)

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Introduction

Illustration of the femoral nerve and femoral triangle and the sensory distribution

Diagram of typical anatomical relationship of femoral nerve and iliacus muscle. Variant path is mapped in red

Motor branches of the femoral nerve.

General

• Femoral neuropathies predominantly present with weakness of the quadriceps muscle group, although there is significant variability
• Patients can have merked morbidity secondary to functionally limtiing proximal lower extremity weakness and pain
• Management is etiology specific and most patients can be treated with physical therapy, knee bracing

Etiology

• Direct trauma
• Compression
  • Can be compressed within the psoas muscle, most commonly associated with hemorrhage
• Stretch injury
• Ischemia
• Diabetes Mellitus
  • Patients with diabetes can deveop femoral mononeuropathies
  • One study found normal EMG/NCS and it was suspected to be related to inflammatory vasculitis
• Iatrogenic
  • Likely the most common cause
  • Can occur due to direct pressure, stretch or trauma during pelvic, abdominal and spinal surgery
  • Less commonly during placement of a central venous catheter or as a complication of hip arthroplasty
• Sports
  • Rare in athletes, limited to a few case reports

Anatomy of the Femoral Nerve

• General
  • Largest branch of the lumbar plexus
  • One of the two major nerves of the lower limb along with the sciatic nerve
  • Nerve roots are L2-L4
  • Primarily responsible for innervating hip flexors, knee extensors and providing sensory to the anteromedial thigh, medial leg
• Anatomic course
  • Travels inferiorly through psoas major
  • Passes underneath the inguinal ligament, enters the femoral triangle
  • Divides into anterior and posterior divisions 4 cm below the inguinal ligament
• Motor: Hip Flexors of the anterior thigh
  • Pectineus
  • Iliacus
  • Sartorius
• Motor: Muscles that extend the knee (quadriceps femoris)
  • Rectus femoris
  • Vastus lateralis
  • Vastus medialis
  • Vastus intermedius
• Sensory
  • Anterior cutaneous branches of the femoral nerve
  • Saphenous Nerve

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Risk Factors

• Surgical
  • Prolonged duratoin of surgery
  • Extreme patient positioning (especially hip extension, abduction, external rotation)
  • Use of self retaining retractions
  • Placement of femoral artery catheters
• Compressive/ Vascular
  • Retroperitoneal/ iliacus hematoma
  • Often related to use of anticoagulation, trauma or coagulopathies
  • Regional lymphadenopathy
• Patient related
  • Prior history of neuropathy
  • Tobacco Use Disorder
  • Prior chemotherapy
• Other
  • Direct trauma
  • Patellar dislocation
  • Perioperative vascular compramise

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Differential Diagnosis

Differential Diagnosis Groin Pain

• Intra-articular / Hip Etiology
  • Femoroacetabular Impingement
  • Acetabular Labral Tears
  • Injuries to the Ligamentum Teres
  • Hip Osteoarthritis
  • Avascular Necrosis of the Femoral Head
  • Osteochondral Defect of the Hip (Loose Bodies)
  • Hip Microinstability
• Extra-articular Causes
  • Pelvic Stress Fracture
  • Osteitis Pubis
  • Sports Hernia (Athletic Pubalgia)
  • Avulsion Fractures of the Pelvis
  • Snapping Hip Syndrome
  • Iliopsoas Tendinopathy
  • Rectus Femoris Strain
  • Rectus Abdominal Strain
  • Myositis Ossificans
  • Iliac Apophysitis (AIIS, ASIS, Iliac Crest)
  • Inguinal Hernia
  • Femoral Hernia
  • Adductor Tendonitis
  • Adductor Strain
• Neuropathic/ Nerve Entrapment Syndromes
  • Obturator Neuropathy
  • Femoral Neuropathy
  • Iliohypogastric Nerve Injury
  • Genitofemoral Nerve Injury
  • Ilioinguinal Nerve Injury
  • Meralgia Paresthetica (Lateral Femoral Cutaneous Nerve)
  • Pudendal Neuralgia
• Axial/Spinal Etiology
  • Lumbar Disc Disease
  • Facet Arthropathy
  • Sacroiliitis
  • Sacroiliac Joint Dysfunction
• Pediatric Considerations
  • Legg Calve Perthes Disease
  • Slipped Capital Femoral Epiphysis
  • Transient Synovitis of the Hip
  • Idiopathic Chondrolysis of the Hip
• Intra-abdominal Considerations
  • Abdominal Aortic Aneurysm
  • Appendicitis
  • Diverticulitis/ Diverticulosis
  • Lymphadenitis
  • Inflammatory Bowel Disease
• Genitourinary Considerations
  • Ovarian/Testicular Torsion
  • Ectopic Pregnancy
  • Nephrolithiasis
  • Epididymo-Orchitis
  • Ovarian Cyst
  • Pelvic Inflammatory Disease
  • Round ligament pain
  • Urinary Tract Infection
  • Endometriosis
  • Prostatitis
  • Testicular cancer

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Clinical Features

Comparison between the affected limb (patient left) and unaffected limb. Clinical evaluation reveals muscle atrophy, decreased strength in knee extension, progressive loss of weight bearing capacity

History

• Patients will report difficulty climbing stairs, frequent falls second to knee buckling
• Weakness is usually acute or subacute
• Important to characterize natural history of the symptoms and any possible inciting event
• Patients may have acute, severe pain in the groin, thigh, lower abdomen
  • This is often associated with a retroperitoneal hematoma
• Otherwise pain is usually mild, located near inguinal ligament
• Numbness can occur in the medial thigh and calf

Physical Exam

• Weakness of quadriceps muscle
• Decreased patellar tendon reflex
• in more chronic cases, atrophy or wasting of the quadriceps may be noted
• Passive hip extension can be painful if a retroperitoneal hematoma is present
• If weakness is found in the iliopsoas, the lesion is above the inguinal ligament before the motor branch nerve
• Thigh adduction should be normal if isolated femoral mononeuropathy
• Patient may have sensory deficits of the medial thigh, anteromedial calf

Special Tests

• Femoral Nerve Tension Test: patient prone, flex knee to 90 degrees and hold for 45 seconds

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Evaluation

Femoral neuropathy. Axial image from T2weighted neurography (4420/145), obtained at the S1 level, shows increased size and increased signal intensity of the left femoral nerve (solid arrow). The right femoral nerve is normal (open arrow).

Femoral neuropathy. a Hip MR AX T2 FS shows thickening and signal alteration of left femoral nerve on the medial border of the left psoas muscle (arrow). b Thigh MR AX T2 FS imaging shows diffuse muscle edema on the anterior compartment, marked involving the quadriceps muscles

Radiographs

• Standard Radiograph Pelvis, Standard Radiograph Hip
  • Typically Normal

CT

• Should be considered if a retroperitoneal hematoma is suspected
• Can help localize site of compression

MRI

• can help localize the site of compression if present

Electromyelogram/ Nerve Conduction Study

• Diagnostic gold standard
• Must get sensory of the saphenous nerve, motor of the femoral nerve
• Compare to the unaffected side
• Quadriceps should show neuropathic changes

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Classification

• Not applicable

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Management

Nonoperative

• Indications
  • Most patients
  • Abscence of clearly surgical pathology
• Physical Therapy
• Activity avoidance
  • Avoid excessive hip abduction and external rotation
• Hinged Knee Brace to prevent buckling
• If painful, neuropathic agents can be considered
  • Gabapentinoids, TCA, Duloxetine
• Timeline
  • If assocaited with positional or retraction compression from surgery/delivery
  • Recovery typically takes 3-4 months
• Retroperitoneal hematoma
  • Surgery is controversial
  • Must stop/ reverse anticoagulation
• If etiology is diabetic, vasculitis then targeted therapy to those conditions

Operative

• Indications
  • Evacuation of retroperitoneal hematoma (controversial)
  • Tumor burden
• Technique
  • Surgical decompression

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Rehab and Return to Play

Rehabilitation

• Strengthening exercises
  • Emphasis on quadriceps, hip flexors
  • Restore motor function, prevent atrophy
• Sensorimotor balance and training
  • Improve proprioception, stability and reduce fall risk
  • Balance exercise particularly important in peripheral neuropathies
• Gait Training
  • Including assist devices as needed
• Neurodynamic training
  • Has been shown to be useful in hemophiliac patients

Return to Play/ Work

• There is no sport specific RTP For femoral neuropathy
• General RTP criteria
  • Restoration of anatomical and functional healing
  • Sort-specific skills
  • Musculoskeletal and psychological readiness
  • Absence of undue risk to the athlete or others

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Prognosis and Complications

Prognosis

• General
  • Prognosis is highly variable with most patients experiencing some degree of recovery
  • Depends on how complete the neuropathy is, the etiology and timing of detection
  • Subjective improvement is common, motor deficits may persist
  • Sensory symptoms resolve more slowly or incompletely
• In one case series of 31 patients measuring outcomes
  • Patients reported excellent (31%), satisfactory (34%), poor (31%) outcomes
  • Degree of axonal loss seemed to influence prognosis

Complications

• Persistent weakness (especially of knee extension and hip flexion)
• Quadriceps muscle atrophy
• Chronic pain
• Sensory deficits in the anteromedial thigh and leg
• Gait instability
• Increased risk of falls
• Assist device for ambulation
• Loss of functional indepdenence

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See Also

• Neuropathies
• Groin Pain Main
• Groin Anatomy
• Physical Exam Groin

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