Hernias (or herniae) in the groin may be either inguinal or, less commonly, femoral in origin.

Epidemiology

In 2005/6 there were 4,583 femoral hernia repairs in NHS hospitals in England:¹

• Of these, 49% were emergency repairs and 48% waiting list repairs.
• This compares with a respective figure of 79,760 for inguinal hernia.

Femoral herniae account for only around 7% of all herniae in the groin:²

• Inguinal hernia is more common in men than in women.
• Femoral hernia is about 4 times as common in women than in men.
• In women, inguinal hernia is more common than femoral hernia.
• The incidence is highest in middle-aged and elderly women, especially if parous.
• They are rare in children and account for about 1% of groin herniae. Sex incidence is equal. Diagnosis is often difficult.³
• In elderly women the incidence of femoral hernia approaches that of inguinal hernia.

Presentation

• Presentation is as a lump in the groin, lateral and inferior to the pubic tubercle but a large hernia may bulge over the inguinal ligament and make differential diagnosis difficult.
• The hernia often appears or swells on coughing or straining and reduces in size or disappears when relaxed or supine.
• There may be a cough impulse.
• It may be possible to reduce the hernia.
• According to findings, the hernia may be classified as reducible, irreducible, obstructed or strangulated.

Investigation

• Diagnosis is largely clinical or even on exploration at operation.
• Herniography may help in the investigation of pain in the groin.
• Imaging techniques are of dubious value.⁴

Differential diagnosis

The differentiation between inguinal and femoral hernia is not easy and doctors often get it wrong. Surgeons, including those in training, tend to be better than GPs but they too are far from perfect and so alternative criteria have been suggested:⁵

• Traditionally it is taught that an inguinal hernia will lie above and medial to the pubic tubercle whereas a femoral hernia lies lateral and below.
• This is not strictly true as the internal ring is always lateral to the femoral canal and a small indirect inguinal hernia will therefore be lateral to the pubic tubercle.
• Also, a direct hernia will be lateral to or above the pubic tubercle.
• A better test might be to place the finger over the femoral canal for reducible herniae and then ask the patient to cough. This landmark is easily felt either by following the adductor longus tendon to below the inguinal ligament and then placing one's fingers anterior and lateral to the tendon or, alternatively, palpating the femoral artery and placing one's hand approximately a finger's breadth medial to it.
• When the patient coughs a femoral hernia should remain reduced while an inguinal hernia will re-appear as an obvious swelling.⁵

Other causes of lumps in the groin include:

• A lymph node in the groin, as with a lymphoma, chancroid or lymphogranuloma venerium
• Ectopic testis
• Psoas abscess
• Psoas bursa
• Lipoma

Complications

The main concern with a hernia is strangulation.

• The risk of strangulation in a femoral hernia is 2% at 3 months and 45% at 21 months.⁶ This is very much greater than for an inguinal hernia.
• Only 50% of patients are aware of the hernia before strangulation.
• Around 60% present in the emergency situation.⁵

Presentation

• If strangulation occurs, the lump will become red and tender as well as tense and irreducible.
• Other features include colicky abdominal pain, distension and vomiting to indicate a surgical emergency.
• Fluid and electrolyte imbalance must be corrected, followed swiftly by repair of the hernia.
• Failure to make a correct diagnosis is common.
• It is associated with a greater risk of needing bowel resection and a higher mortality.⁷

Management

In view of the high risk of strangulation, all femoral herniae should be repaired as an elective procedure, but as soon as possible. There is no place for a truss for a femoral hernia.

• There are 3 surgical approaches, each named eponymously. There is a low approach called Lockwood, a transinguinal called Lotheissen and a high called McEvedy.
• Each technique has the principle of dissection of the sac with reduction of its contents, followed by ligation of the sac and closure between the inguinal and pectineal ligaments.
• A laparoscopic technique that uses mesh and keeps outside the peritoneum seems promising:⁸
  • However with 10 male and 5 female in the series and a mean age of 55 they seem unusually male-dominated and unusually young.
  • Laparoscopic hernia repair has advantages but it should be in the province of the specialist.⁹
  • A Cochrane review found that open mesh repair was associated with a reduced risk of recurrence.¹⁰
• In those who are unfit for general anaesthesia, local anaesthetic may be used.¹¹

Recurrence risk

After hernia repair there is always a risk of recurrence but a mesh plug technique can reduce this.¹²
A survey from Sweden examined the incidence of post-operative intestinal obstruction and found it low at 1.02 per 1,000.¹³ The risk was higher with a transabdominal laparoscopic approach than a totally extraperitoneal laparoscopic hernioplasty but other factors, such as previous abdominal surgery, were more important.

Prognosis

The mortality for elective hernia repair, both inguinal and femoral is:

• 0.1% below the age of 60
• 0.2% between 60 and 69
• 1.6% between 70 and 79
• 3.3% over the age of 80

The risk for emergency repair of a strangulated hernia is 10 times higher and many patients are 80 years or over.
The overall operative mortality for strangulated hernia is 10%:

• High age and the need to resect necrotic bowel increase the risk.
• The death rate from surgery for strangulated herniae has changed little over the past 50 years.
• Hence femoral hernia must be repaired if at all possible, even in the elderly.