SNAPPING HIP SYNDROME
Coxa Saltans | Internal vs External | Iliopsoas vs ITB
Classification Types
Critical Must-Knows
- External Snapping (ITB): Visible snap over later hip. 'I saw it pop out'.
- Internal Snapping (Iliopsoas): Deep audible snap/clunk with hip extension from flexion/abduction.
- Intra-articular: True mechanical symptoms (locking/catching) - usually painful.
- Voluntary: Many patients can reproduce the snap voluntarily.
- Ober's Test: Assessing ITB tightness is key for external type.
Examiner's Pearls
- "Ask the patient to reproduce the snap!
- "Psoas snap: Flexion + Abduction + External Rotation to Extension
- "ITB snap: Flexion/Extension in lateral decubitus
- "Painful vs Painless: Painless snapping requires NO treatment.
Clinical Imaging
Imaging Gallery
Critical Concepts
Is it Intra-articular?
Rule out Labral Tears. Intra-articular pathology presents with sharp groin pain and mechanical locking/catching. Snapping is usually a clunk rather than a click. MRI Arthrogram is the gold standard discriminator.
Psychologica Overlay
Voluntary Snappers. Some patients (often adolescents) habitual snap their hip as a tick. Surgical treatment in painless voluntary snappers has unpredictable (often poor) outcomes. Avoid operating on the 'party trick'.
Types of Snapping Hip
| Feature | External (ITB) | Internal (Iliopsoas) | Intra-articular |
|---|---|---|---|
| Audibility | Sometimes | Often Loud 'Clunk' | Click/Catch |
| Visibility | Visible 'Jump' of ITB | Not visible | Not visible |
| Location | Lateral (Greater Troch) | Anterior (Groin) | Deep Groin/C-sign |
| Provocation | Walking/Running | Extension from Frog-leg | Rotation/Pivoting |
IIESnapping Hip Types
Memory Hook:Two I's inside, One E outside.
SIREManagement Hierarchy
Memory Hook:SIRE: The King of treatments.
FABER-EInternal Snapping Reproduction
Memory Hook:From FABER into Extension snaps the Psoas.
Overview and Epidemiology
Snapping Hip Syndrome (Coxa Saltans) describes a palpable or audible snap occurring around the hip joint during movement. It is classified by the anatomical structure causing the snap.
Epidemiology
- Demographics: Most common in females (wider pelvis increases ITB angle) and adolescents/young adults.
- Athletes: Dancers (Ballet), Gymnasts, Runners.
- Psychosocial: Habitual snapping can be associated with anxiety/compulsion in adolescents.
Risk Factors and Associations
Anatomical Predisposition:
- Coxa vara (prominent greater trochanter increases ITB friction)
- Increased femoral anteversion
- Leg length discrepancy (longer leg has tighter ITB)
- Narrow bi-iliac width (common in dancers)
Activity-Related Factors:
- Sports involving repetitive hip flexion/extension (cycling, running)
- Dance (especially ballet with extreme hip positions)
- Martial arts (high kicks)
- Soccer (kicking sports)
Biomechanical Factors:
- Gluteal weakness (poor hip control)
- Core instability
- Tight hip flexors
- ITB tightness from overuse
Pathophysiology and Mechanisms
Internal Snapping
Structure: Iliopsoas Tendon. Mechanism: The tendon snaps over the Iliopectineal Eminence or the Femoral Head. Motion: Occurs when the hip moves from Flexion/Abduction/External Rotation (FABER) into Extension/Adduction/Internal Rotation. The tendon flips from later to medial. Bursa: Often associated with Iliopsoas bursitis (pain).
Classification Systems
Anatomical Classification
Based on the location of the snap relative to the joint:
- Extra-articular Lateral (External): Iliotibial Band or Gluteus Maximus.
- Extra-articular Anterior (Internal): Iliopsoas Tendon.
- Extra-articular Lateral (External): Iliotibial Band or Gluteus Maximus.
- Extra-articular Anterior (Internal): Iliopsoas Tendon.
- Intra-articular: Labrum, loose bodies, cartilage flaps.
This helps guide anatomical target.
Clinical Assessment
History
- Describe the sound: "Pop", "Click", "Clunk".
- Location:
- Lateral corresponds to External (Patient points to trochanter).
- Groin corresponds to Internal or Intra-articular.
- Pain: Is it painful? Painless snapping is physiologic and needs no treatment.
- Voluntary: Can you do it right now? (Demonstration is diagnostic).
Physical Examination
External Snapping:
- Ober's Test: Assess ITB tightness.
- Reproduction: Patient side-lying. Passive flexion/extension of hip while compressing ITB against greater trochanter. Palpable "jump".
Internal Snapping:
- Thomas Test: Assess Psoas tightness (fixed flexion deformity).
- Dynamic Test: Patient supine. Flex, Abduct, Externally Rotated hip actively extended. Palpable "clunk" anteriorly.
Intra-articular:
- FADIR Test: Impingement test / Labral loading.
- Scour Test: Grinding femoral head.
Investigations
Radiographs
- Usually Normal.
- Check for: Cam/Pincer FAI, DDH, Dysplasia (Intra-articular associations).
Dynamic Ultrasound
- Diagnostic of choice for Snapping.
- Real-time visualisation of the tendon snapping over bone.
- Can see bursitis.
- Can perform diagnostic injection.
MRI / MRA
- Role: Ruling out Intra-articular pathology (Labral tear).
- Internal: May show Iliopsoas bursitis.
- External: Gluteal tendinopathy / ITB thickening.
MRI Arthrography is gold standard for Labral tears.
Management Algorithm
Treatment Ladder
If painless: "It's noisy but normal." No treatment. Education.
Stretching (ITB/Psoas). Core strengthening. Gluteal strengthening. Activity modification.
Ultrasound-guided steroid injection into Iliopsoas bursa or Trochanteric bursa. Diagnostic + Therapeutic.
Only for refractory PAINFUL snapping (rare). Technique depends on type.
Surgical Technique
Arthroscopic Psoas Fractional Lengthening
Goal: Lengthen the tendon without complete release (preserve power). Technique:
- Hip Arthroscopy / Endoscopy.
- Transcapsular approach (from central compartment) or Endoscopic (from peripheral compartment at Lesser Trochanter).
- Fractional Lengthening: Cut tendon portion only (musculotendinous junction level).
- Reduces tension, stops snapping.
- Fractional Lengthening: Cut tendon portion only (musculotendinous junction level).
- Reduces tension, stops snapping.
- Risk: Hip Flexion weakness (significant).
Preserve the tendon to preserve power.
Complications
| Complication | Risk | Note |
|---|---|---|
| Hip Flexion Weakness | High (Internal) | Psoas release causes permanent weakness (esp greater than 40) |
| Recurrence | 10-20% | Re-scarring or insufficient release |
| Heterotopic Ossification | Rare | Usually asymptomatic |
| Nerve Injury | Rare | Lateral Femoral Cutaneous Nerve (External) |
Detailed Rehabilitation
Specific Exercises by Phase
Phase 1: Mobilization & Activation (Weeks 0-4)
- Glute Bridges: 3 sets of 15. Focus on squeeze.
- Clamshells: 3 sets of 15. Banded resistance.
- Psoas Stretch: Kneeling lunge. Hold 30s.
- ITB Foam Roll: Patient guided self-myofascial release.
Phase 2: Strengthening (Weeks 4-8)
- Single Leg Deadlift (RDL): Excellent for posterior chain.
- Lateral Band Walks: Gluteus Medius recruitment.
- Bulgarian Split Squat: Eccentric Psoas control.
- Monster Walks: Forward/Backward with band.
Phase 3: Return to Sport (Weeks 8+)
- Plyometrics: Box jumps (landing mechanics).
- Cutting Drills: 45 degree cuts.
- Sport Specific: Kicking (soccer) or Pointe work (ballet).
Note: For Psoas release patients, avoid active hip flexion against resistance for first 4 weeks.
Postoperative Care
Rehabilitation Protocol
- Weight Bearing: WBAT with crutches for 2 weeks (Psoas release).
- ROM: Unlimited ROM immediately to prevent scarring (Use Stationary Bike).
- Strengthening:
- Week 1-4: Isometrics.
- Week 4-8: Concentric loading.
- Week 8+: Sport specific.
Return to Sport:
- External: 6-8 weeks.
- Internal: 12-16 weeks (due to weakness).
Outcomes and Prognosis
Prognostic Factors
- Pain: Pre-operative pain is the best predictor of surgical success. Painless snappers do poorly with surgery.
- Weakness: Up to 40% of patients report subjective weakness after psoas release, though most return to sport.
- Recurrence: Higher in Z-plasty than endoscopic release.
Overall: Good outcomes in properly selected patients (Refractory pain, failed 6 months of rehab).
Long-Term Outcomes by Type
External Snapping (ITB):
- 90% success with conservative management alone
- Z-plasty or endoscopic release provides 85-95% good/excellent outcomes
- Recurrence rate 5-10% with adequate lengthening
- Athletes typically return to full sport by 8-12 weeks post-surgery
Internal Snapping (Iliopsoas):
- Higher surgical recurrence rate (10-20%)
- Hip flexion weakness persists in 20-40% at 6 months
- Most weakness is compensated over time but may limit elite athletes
- Dancers may notice decreased grand battement power
Intra-articular:
- Outcomes depend on underlying pathology (labral tear vs loose body)
- Arthroscopic labral repair has 75-85% good outcomes at 5 years
- FAI correction improves long-term joint preservation
- OA progression may occur despite intervention
Evidence Base
Endoscopic lengthening
- Effective for internal snapping
- Minimally invasive
- Weakness is the main concern
Release vs Lengthening
- Don't cut the whole tendon
- Lengthening preserves power
- Better outcomes
Ultrasound Diagnosis
- Dynamic US is superior to MRI
- Real-time correlation
- Can see tendon flip
External Snapping Hip Treatment
- Z-plasty of IT band effective in 90% of cases
- Diamond excision alternative technique
- Rehabilitation focuses on hip abductor strengthening
- Recurrence rare with adequate lengthening
Iliopsoas Impingement After THA
- Psoas impingement from prominent acetabular component in 4% of THA
- Groin pain and snapping are cardinal features
- CT confirms cup position and anterior overhang
- Psoas release or cup revision required for refractory cases
Exam Viva Scenarios
Practice these scenarios to excel in your viva examination
Scenario 1: The Clicking Hip
"A 16-year-old female dancer complains of a loud 'clunk' in her groin when she extends her leg from a high kick. It is occasionally painful. She can reproduce it on demand."
Scenario 2: The Visible Snap
"A 22-year-old cyclist has lateral hip pain and a visible snap over the trochanter when walking. He has failed foam rolling and stretching. Ober's test is positive."
Scenario 3: The Locking Hip
"A 30-year-old footballer presents with groin pain and locking. He describes a deep 'clunk'. He has a positive FADIR test. Plain films show a Cam lesion."
MCQ Practice Points
Anatomy - Internal
Q: What structure does the psoas tendon snap over? A: Iliopectineal Eminence (pelvic brim) or the Femoral Head.
Anatomy - External
Q: What structure does the ITB snap over? A: Greater Trochanter. Specifically the posterior third of the ITB.
Complications
Q: What is the most common significant complication of psoas release? A: Hip Flexion Weakness. Can be permanent and disabling for athletes.
Imaging
Q: What is the investigation of choice? A: Dynamic Ultrasound. Allows real-time visualization of the snapping event.
Incidence
Q: Which demographic is most affected? A: Young Females. Particularly dancers and gymnasts (flexibility + anatomy).
Australian Context
Ballet Schools
- High prevalence in elite ballet schools (Aus Ballet School).
- Managed by physios with specific expertise in dance medicine.
Surgical Trends
- Increasing use of endoscopic shelf release for external snapping (Gluteal Max).
- Psoas release is falling out of favor due to weakness concerns.
SNAPPING HIP SYNDROME
High-Yield Exam Summary
Classification
- •Internal: Iliopsoas (Groin clunk)
- •External: ITB (Lateral pop)
- •Intra-articular: Labrum (Click/Catch)
- •Voluntary vs Involuntary
Diagnosis
- •Clinical Reproduction is key
- •Dynamic Ultrasound = Gold Standard
- •MRI to exclude labral tear
- •Ober Test for ITB tightness
Management
- •Painless = No treatment
- •Painful = Physio + Injection
- •Surgery = Last resort (Release/Lengthening)
- •Risk: Flexion Weakness (Psoas)
Anatomy
- •Psoas to Iliopectineal Eminence
- •ITB to Greater Trochanter
- •Labrum to Acetabular Rim
- •Bursa involved in both