Overview
A femoral hernia describes the protrusion of abdominal contents (such as parts of the bowel) through the femoral canal, resulting in a groin lump. They account for around 5% of abdominal hernias and are much less common than inguinal hernias.
Anatomy
The femoral canal is found in the anterior thigh and contains lymph nodes, lymph vessels and some connective tissue. It is found medial to the femoral vein and is thought to help in allowing the femoral vein to expand when blood flow from the lower limb increase or intra-abdominal pressure increases (e.g. straining to open the bowels), resulting in a temporary stop in femoral vein blood flow. The femoral ring is the entrance to the femoral canal, and when abdominal contents protrude through it, a femoral hernia occurs. Since the femoral ring and canal are relatively narrow, the herniated contents are at a high risk of strangulation.
Epidemiology
- Femoral hernias are much less common than inguinal hernias and make up ~5% of abdominal hernias
- Femoral hernias are much more common in women than men (10:1 ratio), especially if parous (due to increased intra-abdominal pressure)
- Femoral hernias are very rarer in children
Risk Factors
Risk factors include factors that increase intra-abdominal pressure, as this can cause the femoral vein to expand and stretch the femoral ring, increasing the risk of abdominal contents herniating into the femoral canal:
- Causes of increased intra-abdominal pressure:
Presentation
Overview
The risk of strangulation is high in femoral hernias (up to 20% of cases) and its risk increases with time (up to 45% at 21 months). Some studies have shown that up to 45% of people present in an emergency scenario with strangulation and/or bowel obstruction. Key features include:
- A groin lump that is inferior and lateral to the pubic tubercle:
- Many notice the lump just under the inguinal ligament
- It may disappear when the patient lies down and may appear with lifting or causes of increased intra-abdominal pressure
- The lump is usually mildly painful unless strangulation occurs
- The lump is often incarcerated in most cases:
- They cannot be reduced, except in a minority of cases due to how narrow the femoral ring is
- The risk of strangulation is high in femoral hernia:
- Features include severe abdominal pain, nausea, vomiting, and fever, the hernia may be tender, warm, and red or purple
- Features of small bowel obstruction may be present if the hernia contains parts of the small bowel. This can cause bowel ischaemia, necrosis, peritonitis, sepsis, and death.
Management
Overview
Due to the high risk of strangulation, all stable femoral hernias should be repaired electively, but as soon as possible, even if asymptomatic. Trusses are not used in femoral hernias.
Features of strangulation and/or bowel obstruction require immediate hospital admission and emergency surgery.
Complications
- Incarceration – seen in most femoral hernias due to the narrowness of the femoral canal
- Strangulation and bowel obstruction – the risk is high in femoral hernias
- Recurrence – often seen within 2 years after repair, affects up to 10% of people
- Chronic groin pain – up to 15% of patients following surgery
Prognosis
- If repaired electively in the absence of incarceration, strangulation, and/or bowel obstruction, mortality is low. The presence of these complications increases mortality rates significantly (up to 13%)
- Recurrence may occur in up to 10% of people and is often seen within 2 years after repair
