Acetabular Labral Tear

The classic presentation is deep anterior groin pain in a young to middle-aged active adult, often described with the C-sign (the patient cups the hand around the lateral hip with the thumb behind and fingers gripping the groin). Pain is typically activity-related and worsens with deep flexion, prolonged sitting (the movie sign), pivoting, and getting in and out of cars. Mechanical symptoms (clicking, catching, locking, giving way) are common but not universal.

Examination findings cluster around impingement and intra-articular irritation:

• •Range of motion typically shows reduced flexion and internal rotation in flexion
• •FADIR is the most commonly used and most sensitive bedside test for anterior FAI and labral pathology (specificity is moderate)
• •FABER is positive in posterior tears and sacroiliac joint pathology; reduced FABER distance (distance from lateral knee to couch compared with the asymptomatic side) is a reliable marker of restricted hip motion in FAIS
• •Resisted straight leg raise (Stinchfield test)

Always assess for generalised joint hypermobility using the Beighton score, because hypermobility-driven labral tears require a different rehabilitation and surgical strategy.

Differential diagnoses to consider include FAI without labral tear, hip OA, adductor or iliopsoas tendinopathy, athletic groin pain (Doha entities), femoral neck stress fracture, slipped capital femoral epiphysis in adolescents, Perthes in younger children, avascular necrosis (steroids, alcohol, sickle cell), inflammatory arthritis or spondyloarthritis (per NICE NG65), and lumbar radiculopathy.

Imaging starts with plain weight-bearing AP pelvis and lateral hip radiographs (Dunn or cross-table lateral). These assess for:

• •FAI morphology (alpha angle, lateral centre-edge angle)
• •Acetabular retroversion (the crossover sign, where the anterior wall crosses over the posterior wall; the ischial spine sign, where the ischial spine is visible inside the pelvic brim)
• •Dysplasia (lateral centre-edge angle under 20-25 degrees, Tonnis angle)
• •Degenerative change (Tonnis grade)

Plain films do NOT show the labral tear itself.

MRI is commonly used next to assess the labrum, cartilage, and alternative diagnoses. MR arthrography is the imaging of choice in specialist hip-preservation pathways, particularly when standard MRI is equivocal or surgery is being considered: intra-articular gadolinium extends into the labral substance and into the tear plane, improving labral conspicuity. Most tears are anterior or anterosuperior, mirroring the impingement zone.

Image-guided intra-articular local anaesthetic injection is the best test to support an intra-articular pain source when imaging and examination are equivocal. Substantial temporary pain relief supports the hip joint as the source, but does not prove the labrum alone is symptomatic.

CT with 3D reconstruction is reserved for detailed bony morphology when surgery is planned. Diagnostic ultrasound has a limited operator-dependent role and is not standard. Consider lumbar spine imaging when referred lumbar pain is plausible.

Initial management is usually physiotherapy-led in NHS pathways, with education, activity modification (avoiding prolonged deep hip flexion, pivoting, and provocative loading), pain relief, and an individualised strengthening and movement-control programme addressing hip range, deep gluteal and core strengthening, lumbopelvic control, and movement-pattern correction. A 12-24 week structured programme is commonly used before surgical referral, unless red flags, severe mechanical symptoms, or major structural pathology are present. Simple analgesia (paracetamol, short-course NSAIDs per BNF) supports symptom control.

Image-guided intra-articular corticosteroid injection may provide short-term symptom relief and may be combined with local anaesthetic for diagnostic purposes. It does not correct FAI morphology or heal the labrum. Repeated injections in young active patients should be used cautiously and under specialist guidance.

Both physiotherapy-led care and arthroscopy can improve symptoms in selected FAIS patients. Arthroscopy shows superior short-term hip-related outcomes in some secondary and tertiary care RCTs, but conservative care is usually the earlier NHS pathway step. Specialist surgical referral is indicated for:

• •Failure of optimised conservative management at 3-6 months in patients with confirmed intra-articular pathology
• •Mechanical symptoms refractory to rehabilitation
• •Significant FAI morphology with persistent functional limitation

Hip arthroscopy options:

• •Labral repair (suture anchor reattachment, preferred where tissue quality permits)
• •Labral debridement (selected unstable tears)
• •Labral reconstruction (irreparable tears)
• •Concurrent femoral osteochondroplasty (cam resection) or acetabular rim trim (pincer correction) addresses the underlying bony driver

NICE HTG273 (formerly IPG408) supports arthroscopic FAI surgery with normal governance, consent, and audit, ONLY by surgeons with specialist expertise in arthroscopic hip surgery.

The most common complications of hip arthroscopy are traction-related neuropraxias - pudendal nerve neuropraxia (from the perineal post, causing transient groin or genital numbness) and lateral femoral cutaneous nerve injury (anterolateral thigh numbness). Other risks include heterotopic ossification, capsular instability, and (rarely) avascular necrosis.

Important contraindications and cautions:

• •Established hip OA (manage per NICE NG226 - arthroscopy for isolated OA symptoms is inappropriate; Tonnis grade 2-3 or joint space under 2 mm predicts poorer arthroscopy outcomes)
• •Frank dysplasia (LCEA under 20 degrees): refer to a hip-preservation specialist for periacetabular osteotomy assessment - isolated arthroscopy is usually inappropriate, and acetabular rim trimming worsens under-coverage
• •Borderline dysplasia (LCEA 20-25 degrees): management is nuanced and depends on instability, version, cartilage, and symptoms
• •Isolated arthroscopic debridement in marked hypermobility without addressing capsular management often makes symptoms worse

Conservative rehabilitation runs in three phases over 3-6 months:

• •Phase 1 (weeks 0-6): controls pain, restores pain-free range, and reactivates gluteal and core musculature with low-load work
• •Phase 2 (weeks 6-12): progresses to closed-chain strengthening, single-leg work, deeper-range loading within tolerance, and movement-pattern retraining
• •Phase 3 (weeks 12 onwards): reintroduces sport-specific loading, plyometrics, and pivoting in a graded fashion

In hypermobile patients, the emphasis is on motor-control and stability work rather than aggressive range gain, because excess range is the problem.

Post-arthroscopic labral repair rehabilitation follows surgeon-specific protocols but typically involves:

• •Partial weight-bearing on crutches for 2-4 weeks
• •Restricted hip flexion and external rotation for 6 weeks
• •Gradual range progression to 12 weeks
• •Return to running at 3-4 months
• •Return to cutting and pivoting sport at 6-9 months

Return-to-sport criteria are functional (pain-free single-leg hop and agility testing, limb symmetry index over 90%) rather than purely time-based. Recurrence and revision rates are reduced when concurrent FAI bony morphology is addressed.

• •Warwick Agreement on FAI Syndrome (Griffin et al., BJSM 2016): UK-led international consensus defining FAIS as the triad of symptoms, clinical signs, and imaging morphology. Foundational to current UK practice.
• •2018 BJSM consensus on hip-related pain in young and middle-aged active adults: international framework for diagnosis, classification, and management.
• •NICE HTG273 (formerly IPG408) Arthroscopic femoroacetabular surgery for hip impingement syndrome: UK procedural guidance supporting arthroscopy by surgeons with specialist expertise in hip arthroscopy.
• •UK FASHIoN trial (Griffin et al., Lancet 2018): hip arthroscopy produced greater 12-month improvement in hip-related quality of life than Personalised Hip Therapy, with both groups improving.
• •Czerny classification (1996): widely cited acetabular labral tear MRI grading (Stage I-III).
• •NICE NG226 (Osteoarthritis): differential and arthroscopy-caution framework when established hip OA coexists with labral pathology.

• •Anterior or anterosuperior tears predominate (around 75%) and reflect anterior FAI mechanics in flexion, adduction, and internal rotation. FADIR (sensitive, moderate specificity) and the C-sign are the bedside markers; reduced FABER distance signals restricted hip motion.
• •FAI morphology to recognise: cam (alpha over 60 degrees, young male), pincer (LCEA over 40 degrees, retroversion with crossover and ischial spine signs, middle-aged female), and mixed (commonest).
• •A labral tear on MRI is NOT automatically the pain generator. Image-guided intra-articular anaesthetic injection is the best test to confirm an intra-articular source when imaging and examination are equivocal. MR arthrography is the specialist imaging of choice.
• •NICE HTG273 (formerly IPG408) supports arthroscopic FAI surgery only by surgeons with specialist expertise. The commonest complications are pudendal and lateral femoral cutaneous nerve neuropraxia from traction and the perineal post.
• •Hypermobility (Beighton) drives microinstability-related labral tears. Aggressive arthroscopic debridement without capsular consideration can worsen symptoms. Frank dysplasia (LCEA under 20) needs PAO assessment, not isolated arthroscopy.
• •Use Doha Agreement terminology for groin pain. "Sportsman's hernia" and "Gilmore's groin" are discouraged - use "inguinal-related groin pain". Must-not-miss differentials: femoral neck stress fracture, SUFE, AVN, septic arthritis, inflammatory arthritis (NG65), and lumbar radiculopathy.