Hip Labral Injury

Populations and Risk Factors

• Age distribution: young athletes (20–35 years) with traumatic or impingement-related tears; older adults (> 50 years) with degenerative tears coexisting with hip OA
• Sport type: athletes in pivoting and rotational sports — hockey (combined flexion and rotation during skating), soccer, football, ballet, martial arts, running; any sport requiring deep hip flexion under load or repetitive end-range hip motion
• FAI prevalence: cam-type morphology is present in approximately 25% of the general population and up to 50–70% of athletes in certain sports; cam-type FAI is the most common structural cause of labral tears in young adults
• Sex differences: cam-type FAI is more common in males; pincer-type FAI is more common in females; combined cam-pincer (mixed type) is the most common overall pattern
• Hip dysplasia: congenital acetabular undercoverage increases labral loading because the labrum must compensate for the insufficient bony coverage — the labrum bears more compressive load than normal
• Capsular laxity: generalized hypermobility or ligamentous laxity allows excessive femoral head translation, increasing shear forces on the labrum
• Prior injury: hip dislocations, subluxations, or direct impact falls onto the greater trochanter

Causes and Pathophysiology

• Femoroacetabular impingement — cam type: the femoral head has a non-spherical bony prominence (the "bump") at the head-neck junction, typically anterosuperior. During hip flexion and internal rotation, this bump is driven into the acetabular rim, compressing the anterosuperior labrum between the cam lesion and the acetabular cartilage. The cam lesion shears the labrum from the cartilage at the chondrolabral junction, producing an "outside-in" pattern of damage — the labrum is pushed outward and the underlying articular cartilage is damaged from the rim inward. This mechanism explains why cam-type FAI produces both labral tears and early articular cartilage degeneration (and ultimately early-onset hip OA).
• Femoroacetabular impingement — pincer type: the acetabulum has excessive bony coverage (either focal overcoverage from a retroverted acetabulum or global overcoverage — coxa profunda/protrusio). During hip flexion, the femoral neck contacts the overcovered acetabular rim earlier than normal, compressing the labrum directly. The pincer mechanism crushes the labrum between the femoral neck and the bony rim, producing labral degeneration and ossification. Pincer-type damage is typically more localized to the labrum itself, with less initial articular cartilage involvement (unlike cam-type). However, chronic pincer impingement produces a contrecoup lesion — as the femoral head is levered away from the area of impingement, the opposite side of the joint (typically posteroinferior) experiences increased cartilage loading.
• Mixed-type FAI: combined cam and pincer morphology is the most common clinical pattern (approximately 70% of symptomatic FAI cases). Both mechanisms operate simultaneously, accelerating labral damage and articular cartilage degeneration.
• Labral function and the suction seal: the intact labrum creates a seal against the femoral head that maintains negative intra-articular pressure — this "suction cup" effect is responsible for approximately 50% of the hip's passive stability (the bony acetabulum provides the other 50%). When the labrum tears, the seal is broken, intra-articular pressure normalizes, and the femoral head loses its "suction" stability. This loss of seal has two consequences: (1) increased femoral head translation and microinstability, which increases shear forces on the articular cartilage, and (2) altered joint fluid dynamics — the labrum normally channels synovial fluid across the articular surface for nutrition and lubrication. Labral damage disrupts this fluid distribution, accelerating cartilage degeneration. This is why labral tears, even when asymptomatic, predispose to hip OA.
• Clicking and catching mechanism: as the femoral head rotates during hip motion, the torn labral fragment can displace into the joint and then snap back into position, producing a mechanical click or catch. Anterior labral tears (the most common location — 90% of tears) produce clicking during combined flexion and internal rotation (the FADIR position) because the anterosuperior labrum is compressed and the torn fragment is forced into or out of the joint.
• Groin pain pattern: the hip joint is innervated by the obturator nerve, femoral nerve, and nerve to quadratus femoris. Intra-articular hip pathology (including labral tears) refers pain to the anterior groin and medial thigh via the obturator nerve and anterior hip/proximal thigh via the femoral nerve. The "C-sign" — the patient cups their hand around the lateral hip/groin in a C-shape when asked to locate the pain — is a characteristic clinical finding in hip labral pathology.
• Compensatory muscular consequences: the hip joint relies on both passive (labral seal, capsular ligaments) and active (muscular) stabilizers. When the labral seal is disrupted, the active stabilizers — particularly the iliopsoas (anterior), hip adductors, and deep external rotators — increase their activation to compensate for the lost passive stability. The iliopsoas becomes especially hypertonic because it crosses the anterior hip joint and its tendon directly overlies the anterior labrum; iliopsoas hypertonicity is therefore both a consequence of labral injury (compensatory stabilization) and a contributor to ongoing labral irritation (dynamic anterior impingement from the taut iliopsoas compressing the labrum).

Signs and Symptoms

• Groin pain: deep anterior groin pain is the cardinal symptom — present in approximately 90% of labral tears; the patient often demonstrates the "C-sign" (cupping the hand around the hip/groin area); pain may radiate to the medial thigh or anterior thigh via obturator and femoral nerve referral
• Mechanical symptoms: clicking, catching, locking, or a sensation of the hip "giving way" during rotation under load; these symptoms suggest a displaced labral fragment or unstable labral flap and are most prominent during pivoting movements
• Activity-specific provocation: pain worsened by pivoting, prolonged sitting (hip flexion with compression), crossing legs, getting in/out of a car (combined flexion and rotation), deep squatting, and sustained or end-range hip flexion activities; running may provoke symptoms during push-off phase
• Antalgic gait: shortened stance phase on the affected side; may avoid hip extension during push-off (extension compresses the posterior labrum); Trendelenburg sign may be present if hip abductor fatigue develops from compensatory overwork
• Secondary pain sites: compensatory low back pain (increased lumbar extension to avoid hip flexion), lateral hip pain (gluteus medius overload), ipsilateral knee pain (altered hip mechanics transferring load distally)
• Night pain: may report difficulty sleeping on the affected side or pain with hip flexion/rotation in bed; this suggests significant labral irritation with inflammatory component

Assessment Profile

Subjective Presentation

• Chief complaint: "I have a deep ache in my groin that clicks when I move my hip" or "My hip catches and gives way during sports"; pain is typically described as deep and difficult to localize precisely; the patient often demonstrates the C-sign
• Pain quality: deep, aching groin pain; may be described as sharp during clicking/catching episodes; dull ache at rest after provocative activities; pain is disproportionate to visible findings (no swelling, no bruising) — this mismatch between symptoms and visible pathology is characteristic of intra-articular hip conditions
• Onset: insidious onset in FAI-related tears (gradual worsening over months to years with pivoting sports); acute onset in traumatic tears (specific fall, impact, or forceful hip movement); degenerative tears present with gradual onset of groin stiffness and aching in older adults
• Aggravating factors: pivoting and rotation under load, prolonged sitting (especially in deep chairs or car seats), crossing legs, getting in/out of vehicles, deep squatting, sustained hip flexion, running (particularly sprinting), lateral movements, end-range hip motions
• Easing factors: rest, avoiding end-range hip positions, position changes from prolonged sitting, gentle movement (mid-range hip ROM may feel comfortable compared to end-range); NSAIDs may provide temporary relief of the inflammatory component
• Red flags: acute hip dislocation — fixed deformity, inability to bear weight, severe pain, shortened and externally rotated limb — emergency referral; avascular necrosis of the femoral head — progressive groin pain at rest without clear mechanical provocation, night pain, history of corticosteroid use or alcohol abuse — refer for imaging

Observation

• Local inspection: typically no visible swelling, bruising, or deformity (the hip joint is too deep for external swelling to be visible); chronic cases may show gluteal atrophy (particularly gluteus medius/maximus) from altered gait and disuse; iliopsoas may appear prominent or contracted in standing
• Posture: may stand with the affected hip slightly flexed and externally rotated (a position that moves the labrum away from the impingement zone); anterior pelvic tilt is common — compensates for hip flexion limitation by tilting the pelvis; may have subtle limb length discrepancy from altered pelvic mechanics
• Gait: antalgic gait with shortened stance phase on the affected side; reduced hip extension during push-off (avoiding posterior labral compression); Trendelenburg sign may be present indicating gluteus medius fatigue or inhibition; may show increased trunk lean over the affected side (compensated Trendelenburg)

Palpation

• Tone: iliopsoas — hypertonic and tender from the compensatory stabilization pattern described in Pathophysiology. Hip adductors (particularly adductor longus and pectineus) — hypertonic from compensatory medial stabilization. Deep external rotators (piriformis, obturator internus) — hypertonic. Lumbar erectors — may be hypertonic bilaterally but more pronounced on the affected side. Gluteus medius — may show fatigue-related tenderness from overwork or inhibition from pain.
• Tenderness: anterior hip/groin — deep tenderness over the anterior hip joint (the labrum is not directly palpable, but pressure over the anterior capsule compresses the labrum). Greater trochanter — tenderness from gluteus medius/TFL overload. Iliopsoas tendon — tender at the musculotendinous junction in the femoral triangle. Adductor origins — tenderness at the pubic tubercle from compensatory overload.
• Temperature: usually normal; the hip joint is too deep for surface temperature changes to be clinically detectable in most cases
• Tissue quality: iliopsoas feels ropy and taut with reduced fascial mobility in the femoral triangle; hip adductors may have trigger points that refer to the medial thigh; gluteal tissues may feel inhibited and diminished (reduced bulk and firmness) from chronic compensatory guarding; hip capsular restrictions may be palpable as reduced passive accessory mobility during joint play assessment

Motion Assessment

• AROM: hip flexion is typically full or mildly limited; internal rotation is commonly restricted (this is the most consistently limited movement in labral tears, particularly with FAI — the cam or pincer lesion physically blocks IR); combined flexion + adduction + internal rotation (FADIR position) is the most provocative AROM combination; pain may occur at end-range flexion with a sharp "catch"; external rotation in flexion (FABER position) may reproduce groin or posterior hip pain
• PROM / end-feel: passive internal rotation in 90 degrees flexion is often restricted with a bony or firm end-feel (bony block from FAI morphology) or a guarded end-feel (muscle spasm protecting the impingement zone); passive FADIR reproduces deep groin pain — this is both a provocation test and a PROM assessment; FABER distance (the distance from the lateral knee to the examination table) may be increased on the affected side; the hip does NOT typically follow a capsular pattern (IR > flexion > abduction as in OA) — labral tears produce a non-capsular pattern where IR restriction predominates
• Resisted testing: resisted hip flexion may reproduce groin pain (iliopsoas contraction compresses the anterior labrum); resisted adduction may be painful from compensatory adductor overload; resisted internal and external rotation may provoke clicking or deep joint pain; strength is typically preserved unless chronic compensatory patterns have produced gluteus medius inhibition

Special Test Cluster

Note on FADIR sensitivity vs. specificity: FADIR is extremely sensitive (rarely misses a labral tear) but not specific — it can be positive in FAI without labral tear, hip capsulitis, iliopsoas bursitis, and chondral injury. Use the full cluster (FADIR + FABER + scour + log roll) to increase diagnostic confidence. A positive FADIR with positive scour (clicking/catching) and positive log roll strongly suggests labral pathology.

Differential Diagnoses