Groin Injuries

Groin Anatomy

The two hip bones—the os coxae—are connected to the spine at the sacroiliac joints and to the lower extremities at the hip joints. Anteriorly, the hip bones join at the pubic symphysis. Together with the sacrum and coccyx, they comprise the pelvic girdle. The pelvic girdle is very stable, with small movements occurring at the pubic symphysis and in the sacroiliac joints. The hip bone is formed by three separate bones, which fuse with skeletal maturity: the ossa ilium, ischium, and pubis. These three bones join together in a Y-shaped area of cartilage in the acetabulum. The hip joint is a large ball-and-socket joint where the acetabulum articulates to the femoral head. A cartilage ring, the labrum, which helps to provide stability to the joint by deepening the socket, covers the bony rim of the acetabulum.

The term “groin area” usually refers to the junction between the lower abdomen and the anteromedial part of the thigh. Numerous muscles act as stabilizers for the pelvis and have their origins and insertions on the pelvic girdle. Consequently, many muscular attachments are found on the iliac crest of the os ilium, as well as the superior and inferior rami of the os pubis. The insertion of the rectus abdominis muscle and the origins of the adductor muscle group are located medially, near the pubic symphysis. The adductor muscle group consists of five separate muscles: the adductor longus, the adductor brevis, the adductor magnus, the gracilis, and the pectineus. The abdominal wall muscles (the rectus abdominis, the transversus abdominis, and the internal oblique and external oblique muscles) are located above the inguinal ligament. The aponeurosis of the external oblique muscle is part of the anterior wall of the inguinal canal, and the aponeurosis of the internal oblique and transversus abdominis muscles are part of the posterior wall of the inguinal canal as they insert into the pubic bone as the conjoint tendon (the falx inguinalis). The relationship between the abdominal muscles and the adductor muscles is a superficial connective tissue connection. The important main insertion of these muscles are individual into the pubic bone and they do not have a direct biomechanical relevant connection to each other.

Located anterolaterally and proximally on the femur, distal to the inguinal ligament, are the muscle bellies of the sartorius muscle, which has its origin at the anterior superior iliac spine (ASIS), and the rectus femoris muscle, which has its origin at the anterior inferior iliac spine (AIIS). The iliopsoas muscle is located deeper in the groin and consists of the iliacus muscle, arising from the wing of the os ilium, and the psoas major muscle, arising from T12 to L5. The iliopsoas inserts on the lesser trochanter of the femur and acts as a strong hip flexor. Located posterolaterally are the gluteus muscles, which consist of three layers: the gluteus maximus (the primary function of which is hip extension), followed by the gluteus medius in the middle layer (the primary functions of which are abduction and rotation of the hip), and the gluteus minimus in the deepest layer (the primary function of which is abduction).

Anteriorly, the neurovascular bundle is located superficially in the femoral triangle below the inguinal ligament and between the iliopsoas and adductor longus muscles. The femoral artery is a continuation of the external iliac artery. Medial to the artery is the femoral vein, and lateral to the artery is the femoral nerve. The femoral nerve emanates from the lumbar plexus (L2–L4), innervating the quadriceps muscle and a large cutaneous portion of the anteromedial thigh. Other important nerves innervating the groin area are the ilioinguinal, iliohypogastric, and genitofemoral nerves. The ilioinguinal and iliohypogastric nerves emanate from the nerve roots of T12 and L1. They traverse the psoas major muscle and pierce the transversus abdominis superomedial to the ASIS, and then “zigzag” through the three layers of the abdominal wall muscle. They finally become cutaneous through an opening in the external oblique near the external orifice of the inguinal canal. The ilioinguinal nerve supplies sensory branches to the pubic symphysis, the superomedial aspect of the femoral triangle, and either the root of the penis and the anterior scrotum in the male or the mons pubis and labia majora in the female. In contrast, the iliohypogastric nerve only innervates a small cutaneous region just superior to the pubis, and there is frequently overlap in terms of sensory innervation with both the ilioinguinal and genitofemoral nerves. The latter arises from L1 and L2 and is split into the genital and femoral branches near the inguinal ligament. The genital branch then enters the inguinal canal and innervates, for example, the cremaster muscle and the skin of the scrotum and the adjacent superomedial thigh in the male, and the labia majora and the adjacent superomedial thigh in the female.

Finally, there are a few important bursae in the hip and groin area. For example, anteriorly, between the hip joint capsule and the iliopsoas muscle, the iliopectineal bursa can be found, and lateral to the greater trochanter and the external rotators of the hip is the trochanteric bursa.

5.3 Clinical Examination

Groin injuries are often a major diagnostic challenge, with a number of differential diagnoses for the clinician to consider. For example, 18 different diagnostic entities were recently recorded in the UEFA Elite Club Injury Study for the groin area, ³ the most common being adductor- and iliopsoas-related injuries. However, the third most common diagnostic entity was unspecified groin pain, reflecting the fact that these injuries often present with diffuse and vague symptoms. The underlying primary causes of long-standing groin pain can sometimes be difficult to detect, even in experienced hands, especially as secondary symptoms such as further musculotendinous pain often develop over time. A multidisciplinary approach can sometimes be helpful, and referrals to other practitioners for a second opinion may also be needed. Female players with groin pain should often be examined with a view to ruling out potential gynecological causes.

Note: Previous hip/groin injuries are the most important risk factor when it comes to suffering new groin injuries.

A diagnosis should be made on the basis of a thorough patient history, accompanied by a systematic clinical examination. With acute-onset injuries, the examiner should be able to identify:

If the player felt a “snap” or “pop” when the injury occurred.
If the player was able to continue playing or had to leave the pitch.

With gradual-onset complaints, it is important to:

Find out if there has been any change of training load, footwear, or playing surface.
Carefully establish a pain history.

Buttock and groin pain can indicate hip joint dysfunction. A very common indicator of this is the “C sign” ( ▶ Fig. 5.1), where the patient puts a hand over the lateral part of the hip region, pointing to the posterior part with the thumb, to the lateral part with the palm, and to the anterior part with the other four fingers, indicating that the pain is deep in there where those three points meet.

Fig. 5.1 C-sign.

Anterior groin pain in the midportion of the thigh can be the result of iliopsoas-related pain, while more medial groin pain can be due to adductor-related pain. The possibility of a stress fracture of the pubic bone or the femoral neck should also be considered when anterior groin pain is indicated. When pain is reported in the abdominal muscles, Valsalva-like maneuvers such as coughing and sneezing are usually painful.

The muscles, tendons, nerves, ligaments, and joints in the hip and groin region all interact with and are dependent on each other. Pain and dysfunction in the hip joint, whatever the cause, will affect the surrounding muscles and tendons and can lead to secondary problems. Primary conditions in the surrounding tissue can affect the functioning of the hip joint, leading to synovitis and other painful conditions. It is important to be aware of this interdependence when diagnosing and treating patients with hip and groin pain. It is therefore extremely important to examine both the surrounding extra-articular structures and the hip joints systematically. The synergies between the muscles acting across the pelvis, sacroiliac joints, and hip joints are important for the correct functioning of most movements that involve the extremities. A number of muscle groups interact in the groin area—the adductors, the iliopsoas, and the abdominal muscles—and these are the primary musculotendinous structures that are at risk of being injured in football.

A clinical examination of the groin area should consist of the following:

Visual inspection.
Evaluation of range of motion (ROM).
Impingement tests.
Muscle strength tests.
Palpation.
Local neurological examination.
Other groin-specific tests.

Note: The lower back and the sacroiliac joints should also be examined in a player with groin pain.

5.3.1 Visual Inspection

During the visual inspection, the examiner needs to look for identifying factors such as limping or other types of gait disturbance, swelling, a hematoma, muscle hypotrophy, and leg length discrepancies.

Note: The visual inspection should always be carried out with the patient walking, standing, and lying down.

5.3.2 Evaluation of Range of Motion

The typical ROM for a footballer’s hip is 120 degrees of flexion, 30 degrees of extension, 40 to 45 degrees of internal and external rotation, 30 degrees of adduction, and 40 degrees of abduction. Since the passive ROM is usually greater than the active ROM, the passive ROM should always be included in the examination, even if the player has a pain-free and symmetrical active ROM. In patients with femoroacetabular impingement (FAI), internal rotation is typically reduced to less than 30 degrees.

5.3.3 Impingement Tests

Having tested the passive ROM of the hip joint, the doctor should then conduct the two common tests for FAI: the flexion, adduction, and internal rotation (FADDIR) test and the flexion, abduction, and external rotation (FABER) test. These tests have high sensitivity, but very low specificity; they cannot by themselves diagnose an intraarticular hip problem, but on the other hand if both tests are negative, it is unlikely that a hip joint injury is present.

Flexion, Adduction, and Internal Rotation Test

The FADDIR test, or the anterior impingement test, is carried out with the patient supine ( ▶ Fig. 5.2). The hip is flexed at 90 degrees, adducted, and then rotated internally. The test is considered positive if the known pain in the groin is reproduced during the maneuver. It is important to know that the impingement test will also give rise to pain if the player has an iliopsoas-related injury, on account of the sore muscle being folded (flexion), twisted (adduction), and pulled (internal rotation).

Fig. 5.2 Impingement test.

Flexion, Abduction, and External Rotation Test

In the FABER test, the player lies in the supine position. The legs are moved passively into a “figure four” position. The hip and knee joints are flexed, the hip is abducted and rotated externally, and the ankle is placed just above the contralateral knee. Gentle pressure is applied to the medial side of the knee and a contralateral pressure is exerted on the ASIS to balance the pelvis. The test is considered positive if the known pain is reproduced during the maneuver. If the test results in pain posteriorly or laterally, the sacroiliac joints, the lower back, the hip abductors, and the hip rotators should be considered as possible causes of the pain.

Note: The impingement tests are highly sensitive, but the degree of specificity is considerably lower, meaning that it is not always easy to ascertain the specific location of the injury.

5.3.4 Muscle Strength Tests

Muscle strength should be evaluated against resistance. This is usually done manually by the examiner, but other methods (such as using hand-held dynamometers) may also be helpful. ⁴

Note: The strength of the adductor, iliopsoas, and rectus abdominis muscles should always be assessed systematically when physically examining a footballer with groin complaints.

5.3.5 Palpation

Important anatomical structures to palpate include the pubic symphysis and the immediately adjacent bone, the inguinal ligament and the inguinal canal region, and tendon attachments and muscle bellies (in particular for the adductor longus and the iliopsoas).

The pubic symphysis and the conjoined tendon insertion at the pubic tubercle just medial to the inguinal ligament is palpated in the supine position, as is the area 1 to 2 cm proximal to that insertion.

The palpation of the adductor longus is carried out with the patient supine ( ▶ Fig. 5.3). The hip is flexed, abducted, and rotated externally, with the knee slightly flexed. The examiner, using the right hand on the right leg and the left hand on the left leg, palpates the adductor longus muscle belly with two fingers and follows the tendon to the insertion at the pubic bone. The insertion area, including the bone, is tested with firm pressure up to a radius of about approximately 1 cm².

Fig. 5.3 Adductor palpation.

The iliopsoas can be palpated both above the inguinal ligament at the level of the ASIS and under the ligament medial to the sartorius muscle and lateral to the femoral artery ( ▶ Fig. 5.4a, b). The patient lies supine and proximal palpation is performed with both hands, using fingers to make the palpation as gentle as possible. The fingers are gently pressed posteriorly while pushing the abdominal structures away to reach the iliopsoas muscle. The subject must be relaxed. During distal palpation, the iliopsoas muscle can be identified by asking the patient to elevate the examined leg 5 cm and the correct placement of the palpating fingers can be confirmed.

Fig. 5.4 (a, b) Iliopsoas palpation.

The external orifice of the inguinal canal should be palpated with the patient standing. The orifice is normally the size of a fingertip, but in players with an inguinal hernia, an enlarged orifice is often noted, with the contents of the hernia pushing against the finger when the patient coughs.

Note: The hip joint and the iliopectineal bursa are located too deep in the groin to be palpated.

5.3.6 Local Neurological Examination

A simple neurological examination of the groin area and the lower extremities should always be included to rule out referred pain from the lower back and detect hyperesthesia or hypoesthesia along the cutaneous distribution of the ilioinguinal and genitofemoral nerves.

5.3.7 Other Groin-Specific Tests

The physical examination of a player with groin pain should always also include a squeeze test for adductor-related symptoms and the Thomas test for iliopsoas-related symptoms. A nerve block test to check for ilioinguinal/iliohypogastric nerve entrapment can also be useful, as can a hip joint block test to check for intraarticular pathologies such as osteoarthritis (OA) and labral and/or cartilage lesions. Ultrasonography is often helpful, as the accuracy has been shown to be higher than for landmark-based injections, when placing the blocks.

Adductor Squeeze Test

The adductor squeeze test is performed with the patient supine ( ▶ Fig. 5.5). The examiner stands at the end of the treatment table with the hands and forearms between the subject’s feet to hold them apart. The subject’s feet point straight up, and the subject presses them together with maximum force without lifting the legs or pelvis. The test is positive if it produces pain in the adductor muscle complex. ⁵

Fig. 5.5 Adductor squeeze test.

Thomas Test

The Thomas test is carried out with the patient lying supine with the legs hanging over the edge of the treatment table ( ▶ Fig. 5.6). The subject then flexes one hip by clasping the knee in both hands and pulling it down to his/her chest. The other leg hangs relaxed over the edge of the table. The examiner stands at the end of the table supporting the position by pressing the side of his/her trunk against the foot of the flexed leg. The examiner then places one hand on the femur of the hanging leg just above the knee and presses the leg down to stretch the iliopsoas passively. The test is positive if the known groin pain is reproduced.

Fig. 5.6 Thomas test.

Note: The Thomas test can also identify tightness in the tensor fascia latae (which can be seen from hip abduction during the test) and tightness in the rectus femoris (which can be seen from incomplete knee flexion during the test).

Nerve Block Test

In the nerve block test, the player has to perform an exercise that elicits recognizable pain, such as a straight-leg lift. The examiner then injects a local anesthetic into the area where the ilioinguinal and iliohypogastric nerves pierce the internal oblique muscle. If the nerve block is successful, the skin of the lower abdominal wall and inguinal region (the pubic symphysis and the superomedial aspect of the femoral triangle, as well as the root of the penis and the anterior scrotum in the male or the mons pubis and labia majora in the female) is anesthetized. If the straight-leg lift or another pain-provoking exercise can now be performed without pain, the nerve block test indicates that there may be a symptomatic nerve entrapment. However, in the case of genitofemoral nerve entrapment, blocking the ilioinguinal and iliohypogastric nerves as described above should leave the pain or abnormal sensation unchanged, but blocking the L1 and L2 roots should result in pain relief.

Hip Joint Block Test

In a hip joint block test, the player also has to perform a typical exercise that elicits recognizable pain. The examiner then injects a local anesthetic into the hip joint, preferably ultrasonography guided. If the block is successful, the pain-provoking exercise can now be performed without or with lesser pain than before.

5.4 Radiological Examination

According to the UEFA Elite Club Injury Study, almost one-third of all adductor-related injuries and half of all iliopsoas-related injuries are diagnosed solely on the basis of clinical examinations. ³ Radiographic abnormalities are common in highly active male and female footballers, ⁶ and current evidence on the use of radiographs, ultrasonography, and magnetic resonance imaging (MRI) is based on a relatively small number of heterogeneous studies, which are of varying methodological quality. ⁷ Consequently, the correlation between players’ symptoms and identified radiological abnormalities may be low. Caution should therefore be exercised when using radiological imaging in the diagnosis of injuries.

Standard radiographs should still be carried out in many cases, and other modalities such as MRI or ultrasonography can often be used as well. ³ If the patient history and the clinical examination suggest FAI, an anteroposterior pelvic radiograph ( ▶ Fig. 5.7) and a true lateral radiograph should be obtained. The α angle is measured using the lateral view by drawing a best-matching circle around the femoral head. A straight line is then drawn from the center of the femoral neck to the center of the femoral head, followed by another line from the center of the femoral neck to the superolateral point where the head joins the neck. An angle of more than 55 to 60 degrees is usually considered pathological.