Femoral hernia

A femoral hernia is an uncommon type of inguinal hernia, in which intra-abdominal contents (e.g., intraperitoneal fat, mesentery, bowels) herniate into the femoral canal through the femoral ring. Risk factors for femoral hernias include old age, female sex, obesity, and previous hernia repair. Patients present with a globular swelling inferior to the inguinal ligament and medial to the femoral vein that worsens with coughing or straining. The diagnosis is primarily clinical with ultrasonography being indicated if the diagnosis is inconclusive. Although femoral hernias are uncommon, they are associated with a high risk of incarceration and strangulation and should, therefore, be surgically treated as early as possible. The preferred treatment for non-complicated femoral hernias is mesh hernioplasty, while repair without a mesh is used for complicated femoral hernias.

• Uncommon hernia (∼ 5% of all hernias)
• Sex: ♀ > ♂ (3:1)
• Peak incidence: 40–70 years ^[1]

Epidemiological data refers to the US, unless otherwise specified.

• Advancing age and female sex (see “Epidemiology” above)
• Increased intra-abdominal pressure
  • Obesity
  • Chronic constipation
  • Chronic cough (e.g., due to COPD)
  • Straining during micturition (e.g., due to prostatic hypertrophy)
• Multiparity
• Previous abdominal surgeries (especially those involving the inguinal region)

In contrast to indirect inguinal hernias, which may occur congenitally, femoral hernias are almost always acquired.
References:^[2]

• Boundaries of the femoral canal
  • Anterior: inguinal ligament (Poupart's ligament)
  • Posterior: pubic ramus and pectineal ligament
  • Medial: lacunar ligament (Gimbernat ligament)
  • Lateral: femoral vein
• Typical femoral hernia: (common): protrusion of intraperitoneal contents along with the transverse abdominal fascia through the femoral ring into the femoral canal

To remember the femoral triangle contents, think LaMe NAVEL: (from lateral to medial) femoral Nerve, Artery, Vein, Empty space (femoral canal → femoral hernia), Lymphatics

References:^[1][3]

• Non-complicated femoral hernia
  • A globular, subcutaneous swelling in the groin
    • Localization: inferior to the inguinal ligament, lateral to the pubic tubercle, and medial to the femoral vein
    • Swelling enlarges with coughing (palpable cough impulse) or a Valsalva maneuver
  • Possibly, non-specific, dragging pain
• Complicated femoral hernia: see “Complications” below

References:^[1][4]

• A femoral hernia is primarily a clinical diagnosis.
• Groin ultrasound is used when the diagnosis is inconclusive (see “Differential diagnosis” below).

Femoral hernias can be difficult to palpate in obese patients. Ultrasound is indicated if a femoral hernia is suspected in this patient group!

References:^[5]

• Direct or indirect inguinal hernias (see “Overview of hernias”)
• Femoral pseudohernia
• Lipoma
• Lymph node enlargement
• Femoral artery aneurysm
• Saphenous varix: a dilated, saccular swelling of the great saphenous vein that lies just distal to the junction of the femoral vein and the great saphenous vein
• Psoas abscess

References:^[1]

The differential diagnoses listed here are not exhaustive.

• Non-complicated femoral hernia: early elective surgical repair with mesh hernioplasty (tension-free repair)
• Complicated femoral hernia: (see “Complications” below): herniorrhaphy (non-mesh repair)

All femoral hernias should be surgically repaired because of the high risk of complications.

References:^[6][7][8][9]

• Incarceration: irreducible femoral hernia due to trapped hernia contents in hernia sac
  • Richter hernia: herniation of only a part of the circumference of the bowel wall.
• Strangulation: ischemic necrosis of contents within the hernia sac as blood flow is compromised due to incarceration
  • Warm, tender, and erythematous/discolored swelling
  • Features of mechanical bowel obstruction
  • Possibly fever, leukocytosis, and hemodynamic instability
  • Features of paralytic ileus supervene once bowel perforation and/or peritonitis develop

Reduction of a strangulated hernia should not be attempted because generalized peritonitis would occur following reduction of strangulated bowel loops!

Although femoral hernias account for only about 5% of all hernias, they account for about 40% of all complicated hernias!

A femoral hernia should be considered among 40–70-year-old women presenting with signs of mechanical bowel obstruction!

References:^{[5][8][10][11]}

We list the most important complications. The selection is not exhaustive.