What is a femoral hernia?

What is a Femoral Hernia?

A femoral hernia is a protrusion of abdominal contents (typically bowel or omentum) through the femoral canal below the inguinal ligament, representing an uncommon but high-risk type of groin hernia that disproportionately affects women and carries substantial risk of incarceration, strangulation, and bowel necrosis. 1, 2

Anatomical Definition and Location

• A femoral hernia occurs when intra-abdominal structures herniate through the femoral canal, which lies medial to the femoral vein and below the inguinal ligament 3
• This defect is distinct from the more common inguinal hernia, which occurs above the inguinal ligament through the inguinal canal 4
• The femoral canal represents a potential space that can allow passage of abdominal contents into the upper thigh region 5

Epidemiology and Risk Factors

• Femoral hernias account for only 2-4% of all groin hernias, making them relatively uncommon 6
• Women are disproportionately affected with a female-to-male ratio of 8:1, with 88.7% occurring in females 7
• Women face a substantially higher risk of requiring emergency surgery (40.6% vs 28.1% in men) 6
• The mean age at presentation is approximately 59 years, with a range from 22 to 92 years 7

Clinical Significance and Complications

• Femoral hernias carry the highest incarceration rate of all abdominal wall hernias, with 35.9% requiring emergency surgery compared to only 4.9% for inguinal hernias 6
• The risk of strangulation ranges from 16-36% in emergency presentations, significantly higher than other hernia types 8
• Femoral hernia is an independent risk factor for requiring bowel resection with an odds ratio of 8.31 (P < 0.001) 1, 2
• Bowel resection is required in 22.7% of emergency femoral repairs versus only 5.4% of emergency inguinal repairs 6

Life-Threatening Sequelae

• Strangulated femoral hernias lead to bacterial translocation, intestinal wall necrosis, and potential bowel perforation 9
• Emergency femoral hernia operations carry a 10-fold increased mortality risk compared to elective repairs 6
• Mortality rates reach 17.5% for incarcerated postoperative hernias, with the presence of necrosis being the single most important mortality factor (OR = 11.52) 9
• Delayed treatment beyond 24 hours dramatically increases mortality, with a 2.4% increase in mortality per hour of delay 9

Diagnostic Challenges

• Femoral hernias present more difficulty in diagnosis than other external abdominal hernias, often being missed on initial evaluation 8
• Most can be diagnosed clinically, though CT scan is the gold standard for complicated cases 1, 2
• Seven patients in one series had femoral hernias discovered only during laparoscopic exploration for presumed inguinal hernias 7
• Patients without regular physicians or routine physical examinations are at higher risk for developing strangulation due to delayed diagnosis 8

Common Clinical Presentations

• Elective presentations: painless groin mass below the inguinal ligament that may be reducible 5
• Emergency presentations: continuous abdominal pain, inability to reduce the mass, signs of bowel obstruction 9
• Strangulation indicators: systemic inflammatory response syndrome (fever, tachycardia, leukocytosis), abdominal wall rigidity, peritonitis 9
• Richter's hernia variant: partial bowel wall strangulation that can present as spontaneous enterocutaneous fistula in the groin 7

Critical Pitfall to Avoid

The time from symptom onset to presentation varies from hours to years, but symptomatic periods exceeding 8 hours significantly increase morbidity, and delays beyond 24 hours dramatically increase mortality 1, 2, 9. Emergency physicians and primary care providers must maintain high clinical suspicion, particularly in women presenting with groin masses or unexplained bowel obstruction, as early detection is crucial for preventing life-threatening complications 8.