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A Complete Approach to Groin Pain

Vincent J. Lacroix, MD

THE PHYSICIAN AND SPORTSMEDICINE - VOL 28 - NO. 1 - JANUARY 2000


In Brief: Focused history questions and physical exam maneuvers are especially important with groin pain because symptoms can arise from any of numerous causes, sports related or not. Questions for the patient should attempt to rule out systemic symptoms and clarify the pain pattern. Some of the most possible causes of groin pain include stress fracture of the femoral neck or pubic ramus, Legg-Calvé-Perthes disease, slipped capital femoral epiphysis, acetabular labral tears, iliopectineal bursitis, avulsion fracture, osteitis pubis, strain of the thigh muscles or rectus abdominis, inguinal hernia, ilioinguinal neuralgia, and the 'sports hernia.' Depending on the diagnosis, conservative treatment is often effective.

Groin injuries are a diagnostic and therapeutic challenge, even to the most skilled clinician. They are difficult to diagnose and treat correctly because they involve a complex regional anatomy that produces diffuse, insidious symptoms and uncharacteristic presentations; they involve coexisting multiple pathologies; and they are often described with inaccurate terminology.

The term "groin injury" describes multiple clinical conditions without clearly defining location or cause. Groin injury is to the lower abdomen and thigh what shin splints are to the leg. Webster's dictionary defines the groin as "the fold or depression between belly and thighs." Taber's dictionary equates it to "the inguinal region."

"Groin" is a confusing term at best, especially when used in layperson's language. It can, as is usually the case, mean a thigh muscle strain, as in "I think I pulled my groin." It may refer to the genitalia, as in "Doc, I got kicked in the groin." It can indicate hip pathology if it occurs in a child pointing to the anterior thigh while he or she is limping. Finally, it may refer to a lower abdominal wall problem, as in "I have a lump in my groin."

Adding to the confusion caused by inaccurate terminology, the groin is an anatomic area of greatly overlapping nerve distributions. Back pathology and intra-abdominal pathology may cause discomfort that radiates to the groin region, confusing the investigator as to the source of the pain.

The list of causes that can result in groin pain is therefore extensive, as Renström so eloquently described in his landmark 1992 article (1). These include sport-specific injuries as well as ailments more typical of the general population (table 1). Before getting to the sport-specific injuries, the examiner must eliminate the more general causes of groin pain. This task is simple if we consider the anatomic sites that need to be evaluated through history and physical examination. They can be summarized by the mnemonic "How To Approach Groin Pain" (see table 1).


TABLE 1. Differential Diagnosis of Groin Pain, Using a 'How to Approach Groin Pain' Mnemonic

How = Hip/pelvis
To = Thigh
Approach = Abdomen
Groin = Genitalia
Pain = Pain (referred)

Hip/Pelvis
Stress fracture of the femoral neck*
Pubic ramus fracture*
Osteitis pubis*
Legg-Calvé-Perthes disease*
Slipped capital femoral epiphysis*
Avulsion fracture about the pelvis*
Snapping hip*
Acetabular labral tear*
Bursitis (iliopectineal,* trochanteric)
Avascular necrosis
Osteoarthritis
Synovitis or capsulitis


Thigh
Muscle strains
   Adductor longus*
   Rectus femoris*
   Iliopsoas*
   Sartorius*
   Gracilis*
Femoral hernia
Lymphadenopathy


Abdomen
Lower abdominal wall
   Strain of the rectus abdominis*
   Inguinal hernia*
   Ilioinguinal nerve entrapment*
   Sports hernia (hockey player's syndrome)*
Abdominal organ conditions
   Abdominal aortic aneurysm
   Appendicitis
   Diverticulosis, diverticulitis
   Inflammatory bowel disease
   Pelvic inflammatory disease
   Ovarian cyst
   Ectopic pregnancy


Genitalia
Prostatitis
Epididymitis
Hydrocele/varicocele
Testicular torsion
Testicular neoplasm
Urinary tract infection


Pain (referred)
Herniated disk
Renal lithiasis
Spondyloarthropathy


*Common sports-related musculoskeletal cause.


History

The clinician confronted with the prospect of evaluating a patient complaining of groin pain should always ask specific questions that:

Elicit systemic signs and symptoms. Does the patient have a fever, sweats, or chills (indicative of infection or neoplasm)? Has there been weight loss (neoplasm)? What about urinary symptoms (dysuria, urgency, frequency, hematuria [possible signs of sexually transmitted disease or urinary tract infection])? What about bowel symptoms (diarrhea, mucus or blood in the stool [Crohn's disease, ulcerative colitis])?

Clarify the pain pattern. Is the pain acute or chronic? Does the patient have pain at rest or at night (neoplasm) or pain with exertion? What activities cause the pain? What was the mechanism of injury (eg, a sudden turn while running)? Does the pain radiate (eg, to the back, hip, thigh, knee, scrotum, or perineum)? What alleviates the pain (eg, rest, nonsteroidal anti-inflammatory drugs [NSAIDs], acetaminophen, physiotherapy treatments)?

Has there been a change in training regimen (an overload causing a stress fracture)? Is there associated numbness (in what dermatomal pattern)? Has the patient had pain on coughing or sneezing, which increases intra-abdominal pressure (hernia)? Can the patient point to the pain? Is it localized or diffuse? Can he or she reproduce the pain with exertion or with certain movements?

Physical Examination

The physical examination of the groin region (table 2) should proceed through several deliberate steps to screen for various pathologies, which are covered in detail below.


TABLE 2. Physical Examination of the lnguinal Region

Patient's Position Procedure Details

Standing Observe posture, gait, limp, alignment, muscle wasting, ability to sit and stand up -Have the patient point to the area of pain and the pattern of radiation
-Have the patient reproduce painful movements
Examine the low back: active ROM Forward flexion, side bending, extension
Examine the hip: active ROM Trendelenburg's sign (hip adductor strength), ability to squat and duck walk
Examine for hernia Palpate the inguinal region (have the patient cough or strain down)

Supine Examine the abdomen -Palpate for abdominal aortic aneurysm, pain, rebound, guarding, hernia, pulses, nodes
-Test for costovertebral angle tenderness (renal punch)
-When appropriate, perform a rectal exam to palpate the prostate and rule out occult blood
Examine male genitalia Palpate for a testicular mass, varicocele, or tender epididymis
Pelvic exam in women, if appropriate -Look for purulent vaginal discharge of pelvic inflammatory disease and bluish cervix of pregnancy (ectopic)
-Palpate for tender cervix or adnexa, ovarian mass
Examine low back, sciatic nerve roots Perform straight-leg raise test, test for Lasègue's sign and Bragard's sign (dorsiflexion of ankle)
Examine hip motion -Evaluate flexion, external rotation, internal rotation, abduction, adduction, joint play, quadrant tests
-Perform passive straight-leg raise, Thomas, and rectus femoris stretch tests
Palpate pelvic structures Palpate symphysis, pubic rami, iliac crests, adductor insertions, ASIS, PSIS, ischial tuberosities
Examine sacroiliac joints Perform Patrick's (FABERE) test
Look for leg-length discrepancy Verify grossly and determine true length by measuring from ASIS to lateral malleoli

Prone Examine hip motion -Evaluate extension as well as internal and external rotation
-Perform Ely's and femoral nerve stretch test

Side lying Examine iliotibial band Perform Ober's test

Sitting Evaluate muscle strength Test hip flexion (L-2, L-3), hip extension (L-5, S-1, S-2), abduction (L-4, L-5, S-1), adduction (L-3, L-4)
Test reflexes Assess patellar tendon (L-4)
Test sensation Assess lower abdomen (T-12), groin (L-1), medial thigh (L-2), anterior quadriceps (L-3)

ROM = range of motion; ASIS = anterior superior iliac spine; PSIS = posterior superior iliac spine


Hip and Pelvis Injuries

Injuries to the hip and pelvis are some of the most common causes of groin pain. Some of the most common in sports are described below.

Femoral neck stress fracture. Occurring primarily in endurance athletes (often in thin, amenorrheic women), this important overuse injury occurs because of a loss of shock absorption due to muscle fatigue. Other risk factors include training errors, inadequate footwear, running on poor surfaces, and coxa vara (angular deformity of the hip).

Stress fractures of the femoral neck cause groin or anterior thigh pain, often an ache, that is relieved with cessation of activity. Nighttime pain may be present in chronic cases. Examination reveals an antalgic gait and limitation of hip motion, especially internal rotation. Pain is reproduced at the extremes of hip rotation and with axial compression.

Plain radiographs taken early in the injury continuum may be negative. The tension (superior) side fracture may show periosteal callus or an overt fracture line. The compression (inferior) side fracture may show sclerosis or a cortical break. A bone scan should be positive 2 to 8 days after symptoms appear. Further imaging studies such as computed tomography (CT) or magnetic resonance imaging (MRI) should be undertaken early if clinical suspicion warrants it.

Treatment is based on the type of fracture. If the bone scan is positive but there is no visible fracture on plain film, initial treatment will consist of modified bed rest. This will lead to non-weight bearing with crutches and then pain-free weight bearing (2). Cardiovascular workouts should include cycling, swimming, and water running. Some authors suggest weekly radiographs to monitor bone healing. When a hip or pelvis fracture occurs in an amenorrheic athlete, addressing the hormonal, dietary, and psychological needs of the patient is an essential part of any successful management plan.

Treatment for a nondisplaced fracture on the compression side consists of bed rest until the patient is pain free, followed by progressive weight bearing. If there is no improvement in the healing of the fracture, the patient will likely require open reduction and internal fixation (ORIF). For a nondisplaced fracture on the tension side, ORIF is the treatment of choice because of the high risk of displacement. A displaced fracture is considered an orthopedic emergency and requires ORIF.

Athletes must be told that stress fractures of the femoral neck are serious injuries that can compromise their athletic careers. Return to play may take as long as 4 to 5 months in successful cases.

Legg-Calvé-Perthes disease. This is a self-limiting, noninflammatory condition that results in flattening of the weight-bearing surface of the femoral head. It is caused by disruption in the blood supply of the growing femoral head (avascular necrosis) that is thought to be due to antecedent trauma. Occurring usually in children 4 to 8 years of age, it causes pain in the groin, anterior thigh, or knee. For this reason, any athlete younger than 12 years old presenting with knee pain should have a thorough hip examination.

Legg-Calvé-Perthes disease is associated with a painful limp that worsens with activity and is relieved by rest. On examination, hip motion reproduces the pain, and the patient typically has a loss of internal rotation. Chronically, a flexion and adduction contracture may develop. Plain radiographs show an increased density of the femoral epiphysis and an irregular, mottled appearance of the femoral head, sometimes associated with a subchondral fracture.

The primary goal of treatment is containment of the femoral head within the acetabulum. Conservative measures include rest, NSAIDs, traction, and the use of an abduction orthosis. Osteotomy of the femur or pelvis has been described in recalcitrant cases. Return to full activities is permitted when the femoral head demonstrates reossification on radiographs (3).

Slipped capital femoral epiphysis. This progressive or sudden posteroinferior slip of the femoral head at the epiphysis is the most common hip disorder in adolescents. It most commonly affects 10- to 15-year-old boys who are tall and have recently undergone rapid growth, or who are obese and have delayed secondary sex characteristics. While the cause of slipped capital femoral epiphysis is unclear, the mechanically weak zone of the epiphysis separates between the hypertrophying and calcifying cells at a time of imbalance in sex and growth hormones.

Slipped capital femoral epiphysis causes insidious groin, hip, thigh, or knee pain (see caution in previous section about knee pain in those under 12). On examination, the patient has painful limitation of hip motion, with associated psoas spasm. The hip is often held in flexion, with a resulting antalgic or gluteus medius lurch (Trendelenburg gait). External rotation with passive hip flexion results in limited internal rotation and a measurable true leg-length discrepancy. Trendelenburg's sign is usually positive (when the patient stands on one leg, pain in the weight-bearing hip or weakness of the ipsilateral gluteus medius results in a downward pelvic tilt on the contralateral side).

Plain radiographs should include anteroposterior, lateral, and frog lateral views, which may show widening of the epiphyseal line and the degree of slip: Grade 1 is less than one-third the width of the femoral head, grade 2 is one-third to half the width, and grade 3 is more than half the width (2). A rule of thumb on plain radiographs is that the superior line of the femoral neck fails to transect the overhanging ossified epiphysis (figure 1: not shown).

Treatment consists of surgical fixation in situ with threaded pins, with a possible osteotomy. There is a high incidence of avascular necrosis associated with preoperative manipulation in chronic cases (more than 3 weeks). After pinning, activity follows pain tolerance; a slow return to sports activity usually begins at about 6 weeks.

Acetabular labral tears. A high index of suspicion is required to diagnose this uncommon cause of mechanical hip pain. The athlete may experience a feeling of giving way or a sharp catching pain in the groin that radiates into the anterior thigh, especially with a rotation of the hip while arising from a seated position. On examination, a palpable and audible snapping may be elicited with extension and internal rotation of the hip.

Arthrography, MRI, and arthroscopy can be used to confirm the diagnosis. Conservative management with NSAIDs and physiotherapy is usually successful, although arthroscopic or open operative excision may be necessary in recalcitrant cases.

Snapping hip syndrome. This syndrome refers to conditions about the hip that cause an audible or palpable "snapping." The cause can be intra-articular or extra-articular. The most common cause involves the snapping of the iliotibial band or the tensor fascia lata over the greater trochanter of the femur (external snapping).

Less commonly, the iliopsoas tendon may snap as it slides over the iliopectineal eminence, or the iliofemoral ligament may slide over the femoral head (internal snapping). Other causes may include the long head of biceps femoris gliding over the ischial tuberosity and intra-articular pathology such as subluxation of the hip or the presence of loose bodies (2,3).

The athlete may describe associated pain, crepitation, and local warmth, but performance is rarely impaired. Physical examination focuses on localizing the source of the click and associated discomfort.

Treatment consists of modified activity, correcting muscle imbalance and tightness of the involved structures (eg, the iliotibial band or tensor fascia lata), and correcting biomechanical malalignments using orthoses whenever appropriate, as with a leg-length discrepancy. Corticosteroid injections are appropriate if bursal causes can be identified. Surgery is rarely recommended.

Iliopectineal bursitis. This disabling condition usually causes anterior hip pain that can be severe enough to cause a limp. The symptoms are relieved by flexion and external rotation of the hip. The pain may be related to snapping of the iliopsoas tendon over the iliopectineal eminence. Stretching of the iliopsoas tendon by hip extension will usually worsen the discomfort (2,3).

Treatment consists of rest, NSAIDs, and iliopsoas stretching. With recalcitrant cases, operative excision of the offending bursa has been described, but only as a final resort (2,3).

Avulsion fractures about the hip. Avulsion fractures occur more commonly in skeletally immature athletes than in adults because young patients' tendons are stronger than their cartilaginous growth centers. The same stress that causes a muscle strain in an adult can cause an avulsion fracture in an adolescent. These fractures occur at the secondary growth centers, or apophyses, which become separated from the underlying bone. The fractures do not become widely displaced because of the surrounding thick periosteum (2,3).

The mechanism of injury is a sudden, violent muscle contraction or excessive repetitive action across the apophysis. Hip avulsion fractures are common in young sprinters, soccer players, and jumpers. Patients typically describe local pain and swelling after an extreme effort and report no external trauma.

Physical examination reveals ecchymosis and palpable tenderness at specific bony sites (figure 2), most commonly, the anterior superior iliac spine, where the sartorius muscle attaches, the anterior inferior iliac spine, where the rectus femoris muscle attaches, and the ischial tuberosities, where the hamstring muscles attach. Plain radiographs will reveal the avulsion fracture. It is useful to compare the injured side with the contralateral side.

[Figure 2]

Treatment involves rest—paying particular attention to avoid stretching the involved muscle—icing, and analgesics. Patients progress from gentle active and passive range-of-motion exercises to resistance exercises. Stretching exercises and sport-specific exercises are the final steps toward return to competition. Most patients can be treated nonoperatively, although some authors recommend surgery for severely displaced fragments in rare cases.

Pubic ramus stress fracture. Stress fractures of the pubic ramus occur mostly in distance runners and joggers. Differences in gait between the sexes, as well as osteoporosis in the female athlete triad, may account for a higher incidence in females. Traction forces produced by the muscles attaching to the pelvis have been implicated as possible etiologic factors.

Pain in the inguinal, perineal, or adductor region is the usual presenting symptom. On examination, there is no sign of limitation of hip motion, although an antalgic gait is common. Exquisite tenderness over the affected pubic ramus is also common. The positive standing sign (frank pain or an inability to stand unsupported on the affected leg) is pathognomonic of pubic ramus stress fracture.

Plain radiographs may not show a fracture until several weeks after the injury. Bone scan is necessary for early diagnosis.

Treatment consists of cessation of running activities. Cardiovascular fitness can be maintained by performing non-weight-bearing activities such as swimming and cycling. Most athletes will show complete union of bone at 3 to 5 months (2).

Osteitis pubis. This inflammatory lesion of the bone adjacent to the symphysis pubis is thought to be due to mechanical strain from trauma, excessive twisting and turning in sports such as soccer, or repetitive shear stress from excessive side-to-side motion (as in runners with a crossover arm swing). It is common in ice hockey, soccer, and distance running. It is also common in exercising pregnant women and women in the postpartum period because of the particular instability of this joint after birth.

Pain is rarely described by the injured athlete as originating from the symphysis. Instead, pain appears to emanate from the perineal, inguinal, or thigh regions. On examination, however, the pubic symphysis is usually tender to palpation, and the pain can be reproduced by passive abduction and active resisted adduction of the thigh.

Radiographic changes may not be visible for 2 to 3 weeks. Common bone changes are symmetric resorption of the medial ends of the pubic bones, widening of the symphysis, and rarefaction or sclerosis along the pubic rami.

Bone scintigraphy, typically showing increased uptake unilaterally or bilaterally at the pubic bones, is effective in making an early diagnosis.

Treatment initially includes relative rest, icing, and NSAIDs, followed by stretching and strengthening exercises of the adductors. During relative rest, patients maintain fitness with cycling and swimming. Patients typically return to play after 8 to 12 weeks, although this condition is often chronic and recurrent. If symptoms persist, local corticosteroid injections may be attempted.

Because the main differential diagnosis is osteomyelitis, especially in patients having undergone a previous surgical procedure to the pelvic region, corticosteroid injections should be preceded by blood tests aimed at ruling out leukocytosis. That being said, in contrast to osteomyelitis, osteitis pubis is usually bilateral, has no sequestrum, and yields a negative culture (4).

Surgery, in the form of arthrodesis and debridement, has been described for cases unresponsive to conservative therapy (1).

Thigh Muscle Strains

Muscle injuries can result from a variety of causes including poor flexibility, uncoordination, inadequate warm-up, muscle strength imbalance, muscle weakness, fatigue, electrolyte imbalance, poor sports technique, and increased age (3). Some of the most common thigh strains are of the adductor longus, rectus femoris, and iliopsoas.

Adductor longus strain. While the adductor longus, adductor magnus, adductor brevis, and pectineal muscles are all adductors of the hip (figure 3), of these the adductor longus is most often injured in sports (1).

[Figure 3]

The mechanisms of injury to the adductor longus include acute injury—such as a powerful abduction stress during simultaneous adduction of the leg when performing a cutting movement—or overuse, such as repetitive abduction of the free leg in the skating stride. With a sudden change of direction that occurs with sharp cutting movements, a forceful eccentric contraction of the muscle occurs instead of a concentric contraction, causing the strain. While a forceful muscle contraction in an adult may cause a strain in the muscle-tendon unit, the same action in an immature athlete may cause an avulsion fracture (4).

An acute strain will cause pain that feels like a sudden stab in the groin area. If the injured athlete tries to continue the activity, the intense pain will recur. There may be swelling and bruising localized to the origin of the adductor longus tendon or at the musculotendinous junction. Overall, the patient has the classic musculotendinous injury triad: (1) tenderness to palpation, (2) pain with resisted movement (in this case, adduction), and (3) pain with passive stretching (in this case, abduction).

Imaging procedures are usually unnecessary in simple strains, although images may be obtained to rule out more severe injuries such as avulsion fractures. Ultrasound, though operator dependent, is a cost-effective method to confirm muscle tears.

Treatment of acute groin injuries begins with rest from aggravating activities for 1 to 2 weeks. Icing, compression shorts, and NSAIDs provide symptomatic relief. Physiotherapy should begin as soon as pain allows and should initially include isometric contractions without resistance, followed by isometric contractions against resistance, the limit being pain.

After the initial phase of inflammation has subsided, athletes can begin a stretching program. Heat increases the extensibility of the collagen in tendons and muscles and will be beneficial for the remainder of rehabilitation. Maintenance of cardiovascular fitness with aerobic exercises that do not exacerbate the pain should be greatly encouraged. Preventive training and the correction of predisposing factors (eg, intrinsic muscle tightness, muscle strength imbalances, or muscle weakness) should be included in a complete rehabilitation program.

Rectus femoris strain. The rectus femoris is heavily activated and commonly overused during running, jumping, bicycling, and skating (1). Originating just above the acetabulum and inserting as the patellar tendon at the tibial tuberosity (figure 3), the rectus femoris flexes the hip and extends the knee.

The pain from a rectus femoris strain may be felt from the area anterior to the acetabulum and may radiate to the thigh and inguinal area. Pain can be reproduced by resisted hip flexion or resisted knee extension.

Conservative treatment as outlined for injuries of the adductor longus should be used. The risk of myositis ossificans is increased in cases of significant muscle hemorrhage. Initial bleeding leads to formation of a hematoma, which later calcifies within the substance of the muscle, restricting its flexibility (3). Keeping the muscle in a lengthened position can help decrease further bleeding and subsequent heterotopic bone formation. Wrapping the affected area with ice and an elastic bandage, with the knee in maximum flexion, is optimal therapy in the first 24 hours. Some authors believe that NSAIDs should be avoided in the first 48 hours.

Iliopsoas strain. Strain of this strong hip flexor commonly occurs in weight lifting, uphill running, and sit-ups.

Tenderness associated with this strain is difficult to palpate, since the iliopsoas muscle inserts at the lesser trochanter of the femur. If the site is to be successfully palpated, palpation will be done bimanually over the medial aspect of the femur. Pain can be elicited by having the patient flex the hip 90° and then try to flex it further against resistance or by passive stretching with hyperextension at the hip.

Conservative treatment as outlined for injuries of the adductor longus should be used.

Lower Abdominal Wall Injuries

The chief lower abdominal wall injuries in active patients include rectus abdominis strain, inguinal hernia, ilioinguinal neuralgia, and conditions called "sports hernia" and "hockey player's syndrome."

Strain of the rectus abdominis. The rectus abdominis muscle originates on the pubic bone, very close to the origin of the adductor longus. Strain in this muscle is usually caused by overloading, as in weight lifting or doing sit-ups. Pain is localized at the origin and is reproduced by elevating the legs and/or the head with the patient supine.

A rectus abdominis strain can be difficult to differentiate from an intra-abdominal process such as appendicitis. A key diagnostic clue is localized tenderness that is accentuated when the patient contracts the muscle and decreases with muscle relaxation.

Conservative treatment as outlined for injuries of the adductor longus should be used. In chronic, recalcitrant cases, such as significant tears, surgical repair may be necessary.

Inguinal hernia. Hernias are common enough that every patient suffering from groin pain should be examined to eliminate this possibility. An inguinal hernia is located above and medial to the pubic tubercle. A femoral hernia, more common in female patients, is below and lateral to the pubic tubercle.

The most common type of hernia is a direct inguinal hernia, which appears as a diffuse bulge at the internal ring, in the medial part of the inguinal canal. An indirect inguinal hernia is congenital in origin and is caused by a failure of the processus vaginalis to close. It therefore appears at the external ring and may extend into the scrotum. In contrast to what some authors have called "groin disruptions" or in contrast to the "sports hernia" described below, inguinal hernias result from a weakness or tear of the posterior wall of the inguinal canal (transversus abdominis) (1,4).

In most cases, activities that significantly increase intra-abdominal pressure or may involve repeated Valsalva's maneuvers, such as weight lifting, cause or exacerbate the hernia. While the pain might initially occur only after activity, it typically will increase in frequency to the point of occurring during activity and even with simple trunk and hip movements. The pain will often radiate into the proximal thigh or the scrotum in males.

Examination for both types of hernia involves invaginating the scrotal skin along the spermatic cord using the index finger in males or direct palpation in females. A palpable mass may or may not be detected. Maneuvers to increase intra-abdominal pressure, such as coughing or tensing the abdominal musculature, may produce a cough impulse (a sign of hernia), or may make a mass more prominent.

Inguinal hernias should be surgically repaired not only to relieve pain and discomfort, but also to prevent incarceration, obstruction, and infarction of the bowel.

Ilioinguinal neuralgia. The ilioinguinal nerve originates from the L1-2 nerve roots and is similar in course and function to the intercostal nerves (figure 4). It innervates the lowest portions of the transversus abdominis and internal oblique muscles, as well as the skin overlying the inguinal ligament.

[Figure 4]

It transmits sensation from the base of the penis and scrotum (or labium major) along with part of the medial thigh. Direct trauma, intense abdominal muscle training, or inflammatory conditions can lead to entrapment of this nerve as it passes through or close to the abdominal muscle layers. Ilioinguinal nerve entrapment is a well-established cause of chronic inguinal pain in patients who have had lower abdominal surgery (eg, appendectomy or inguinal herniorrhaphy) (5).

Patients will describe a burning or shooting pain in the distribution of the nerve. Light-touch sensation in the inguinal area may be altered, and pain may be exacerbated by hyperextension of the hip. Tenderness may be localized near the anterior superior iliac spine where the ilioinguinal nerve pierces the fascia. The diagnosis can be confirmed by a blockade of the nerve with local anesthetics.

Treatment consists of repeated infiltrations at the confirmed site with anesthetics and/or corticosteroids. Nerve ablation may be indicated in severe cases.

Sports hernia. Athletes in fast-moving sports that involve twisting and turning—like soccer and ice hockey—may be at particular risk of a disruption in the area of the inguinal canal. This injury, often called a "sports hernia," usually involves the posterior wall of the inguinal canal and can appear as a tear of the transversus abdominis muscle or as a disruption to the conjoined tendon, which is the tendon of insertion of both the internal oblique and transversus abdominis muscles (6). A sports hernia may, however, involve the internal oblique muscle and external oblique aponeurosis of the internal inguinal wall (7). It differs from the more common inguinal hernia in that it does not involve a clinically detectable hernia.

A sports hernia typically produces unilateral groin pain during exercise (figure 5). In chronic cases, however, the patient may have symptoms during activities of daily living. Onset of pain is usually insidious but may occur suddenly in some cases. It is typically localized to the conjoined tendon but can involve the inguinal canal laterally. Sudden movements often exacerbate the pain.

[Figure 5]

Examination for the sports hernia is generally done by inverting the scrotal skin with a finger and palpating for pain over the conjoined tendon, pubic tubercle, and midinguinal region. The pain may be exacerbated by sit-ups. Radiographs are important to rule out other injuries.

Treatment is generally surgical. Rehabilitation includes 6 to 8 weeks of pelvic strength, stability, and flexibility exercises and avoidance of sudden, sharp movements.

Hockey player's syndrome. A subset of the sports hernia has been called "hockey player's syndrome." Since 1989, elite ice hockey players have been referred to our center for an atypical lower abdominal pain syndrome (figure 5: not shown) that resembles but does not clearly correspond to previously described entities. In 1998, colleagues and I published a report (5) on 11 of these professional hockey players, a small subset of the 50 or more patients who have now been treated for this condition at our institution.

This hockey player's syndrome—also referred to as the "slap-shot gut"—involves a tear of the external oblique aponeurosis, associated with inguinal nerve entrapment. The pain is muscular in nature, of gradual onset, and exacerbated by ipsilateral hip extension and contralateral torso rotation. Interestingly, it occurs almost exclusively on the side opposite the player's forehand shot. It is felt mostly during the propulsive phase of skating (the first few strides) and during the slap-shot motion. Inherent abdominal wall weakness, musculoskeletal fatigue, and poorly adapted equipment probably all contribute to this overuse injury of the lower abdominal wall.

Physical examination reveals no overt signs of hernia, although palpation of the superficial inguinal ring may reproduce the pain. Conventional imaging modalities such as bone scan, ultrasound, CT, and MRI all fail to reveal the defect. Surgical exploration is currently the only method to confirm the diagnosis.

Surgical treatment involves restoring normal anatomy by repairing the external oblique aponeurosis. Neurectomy of the ilioinguinal nerve is also performed. The patient is advised to refrain from skating or other types of violent twisting and turning motions for 4 weeks postoperatively and is then gradually returned to full activity over the next 6 to 8 weeks. Physiotherapy, pool therapy, stationary cycling, and controlled weight training are the mainstays of rehabilitation (5).

Broad Differential, Focused Treatment

Injuries located within the anatomical area described as the "groin" require astute history-taking and physical-exam skills. Once a careful diagnosis is made, tailored management—often involving conservative measures—will help patients return to full activity as quickly as possible. Judicious use of appropriate diagnostic imaging studies may help focus the large differential diagnosis of these injuries.

References

  1. Renström PA: Tendon and muscle injuries in the groin area. Clin Sports Med 1992;11(4):815-831
  2. Gross ML, Nasser S, Finerman GAM: Hip and pelvis, in DeLee JC, Drez D Jr (eds): Orthopaedic Sports Medicine: Principles and Practice. Philadelphia, WB Saunders Co, 1994, pp 1063-1085
  3. Lieberman GM, Harwin SF: Pelvis, hip, and thigh, in Scuderi GR, McCann PD, Bruno PJ (eds): Sports Medicine: Principles of Primary Care. St Louis, Mosby, 1997, pp 306-335
  4. Ruane JJ, Rossi TA: When groin pain is more than 'just a strain': navigating a broad differential. Phys Sportsmed 1998;26(4):78-103
  5. Lacroix VJ, Kinnear DG, Mulder DS, et al: Lower abdominal pain syndrome in National Hockey League players: a report of cases. Clin J Sports Med 1998;8(1):5-9
  6. Hackney RG: The sports hernia: a cause of groin pain. Br J Sports Med 1993;27(1):58-62
  7. Kemp S, Batt ME: The 'sports hernia': a common cause of groin pain. Phys Sportsmed 1998;26(1):36-44


Dr Lacroix is director of the Primary Care Sports Medicine Fellowship Program in the Department of Family Medicine at McGill University in Montreal. Address correspondence to Vincent J. Lacroix, MD, McGill University Sport Medicine Clinic, 475 Pine Ave W, Montreal, QB, Canada H2W 1S4; e-mail to [email protected].


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