Hip pain is a common and complex complaint, often making it difficult to pinpoint the exact source of discomfort. Since the hip joint is a deep ball-and-socket structure, pain felt in the groin area often originates from within the joint itself. A significant internal cause of this discomfort is an injury to the acetabular labrum, a ring of specialized cartilage. Accurately diagnosing a tear requires a combination of patient history, physical examination maneuvers designed to provoke symptoms, and specialized medical imaging.
Understanding the Hip Labrum and Tear Symptoms
The hip labrum is a cuff of fibrocartilage that lines the rim of the acetabulum (the hip socket). This crescent-shaped structure deepens the socket, contributing to joint stability. It also functions as a suction seal, helping to maintain negative pressure within the joint space for shock absorption and lubrication.
A labral tear can result from a single traumatic event, such as a fall or sports injury, or develop gradually over time. Repetitive microtrauma from activities involving deep hip flexion or twisting motions can lead to fraying. A common underlying cause is femoroacetabular impingement (FAI), where abnormal contact between the femoral head and the acetabulum pinches the labrum.
Patients typically report a sharp, aching pain located deep in the groin, though pain may sometimes present in the buttock or hip flank. Mechanical symptoms, such as a painful clicking, catching, or locking sensation, are also common. These symptoms often worsen with prolonged standing, sitting, or athletic activities that require pivoting or twisting movements.
Primary Physical Examination Maneuvers
During a physical exam, a clinician performs specific movements to mechanically compress or stretch the labrum, aiming to reproduce the patient’s symptoms. A positive result on these provocation tests indicates intra-articular pathology, such as a labral tear. The four primary maneuvers used to screen for this injury are detailed below.
Anterior Impingement Test (FADIR)
The Anterior Impingement Test (FADIR) is the most consistent physical examination finding associated with an anterior labral tear or femoroacetabular impingement. The patient lies on their back while the clinician passively moves the affected hip into maximal Flexion, Adduction, and Internal Rotation. This combination of movements jams the femoral head against the anterior acetabular rim, pinching the labrum. A positive test is the reproduction of the patient’s characteristic sharp groin pain.
FABER Test (Patrick’s Test)
The FABER test (Flexion, Abduction, and External Rotation) is a widely used maneuver, though less specific than FADIR. The patient lies on their back, and the clinician brings the affected leg into a “figure-four” position, resting the ankle above the opposite knee. The examiner then applies downward pressure to the knee, stressing the hip joint. While a positive result can suggest an intra-articular issue like a labral tear, reproduction of posterior hip or buttock pain can also indicate sacroiliac joint involvement.
Posterior Impingement Test
This maneuver assesses for pathology involving the posterior aspect of the hip joint, including posterior labral tears. The patient is positioned on their back, and the clinician passively moves the hip into a combination of Extension, Abduction, and External Rotation. This movement forces the femoral head against the posterior acetabular rim. Reproduction of pain in the posterior hip or groin area indicates a positive test, suggesting a posterior tear or impingement.
Scour Test (Grind Test)
The Scour Test is a dynamic maneuver that applies an axial load while moving the hip through a circular arc of motion. The clinician first flexes the patient’s hip and knee, then applies a compressive force down the shaft of the femur. While maintaining this compression, the hip is rotated and circumducted through varying degrees of flexion and abduction. This action causes the femoral head to “scour” or grind the articular surfaces of the acetabulum. A positive result is the reproduction of pain, clicking, or a catching sensation, suggesting an intra-articular problem like a labral tear or cartilage defect.
Interpreting Test Results and Clinical Specificity
A positive physical examination is only indicative of a labral tear, not a definitive diagnosis. Each special test possesses varying levels of sensitivity and specificity, which describe its accuracy. Sensitivity is the test’s ability to correctly identify patients who have the tear, while specificity is its ability to correctly identify patients who do not have the tear.
For instance, the FADIR test often demonstrates high sensitivity, meaning a negative result can help rule out a labral tear, but its specificity is low. Low specificity means the test can produce false positives because the maneuver stresses other nearby structures like tendons and ligaments. Conversely, some tests may have higher specificity but lower sensitivity.
The diagnostic value of the physical exam significantly increases when multiple tests are positive for the patient’s characteristic pain. A combination of positive findings helps the clinician localize the source of pain to the hip joint. This collective evidence guides the decision for further, more definitive diagnostic steps.
Definitive Diagnosis Through Medical Imaging
Following a positive physical examination, the next step involves medical imaging. Initial plain film X-rays are typically ordered, not to visualize the labrum, but to rule out bony abnormalities. These images assess for conditions that often lead to labral tears, such as arthritis or bony deformities associated with femoroacetabular impingement.
To definitively visualize the labrum and surrounding soft tissues, a Magnetic Resonance Imaging (MRI) scan is required. While a standard MRI can show soft tissue, Magnetic Resonance Arthrography (MRA) is considered the most accurate non-invasive method. The MRA procedure involves injecting a contrast dye directly into the hip joint space. This dye seeps into any tears or defects in the labrum or cartilage, outlining the extent and location of the injury and improving diagnostic accuracy.