High Yield Overview
ANKLE IMPINGEMENT SYNDROMES
Anterior (Footballer's Ankle) and Posterior (Dancer's Syndrome) | Arthroscopic Treatment
85-95%surgical success rate
10-25%os trigonum prevalence
3-5 monthsreturn to sport
88-91%good-excellent outcomes
IMPINGEMENT TYPES
Anterior Osseous
PatternTibial/talar osteophytes (footballer's ankle)
TreatmentArthroscopic osteophyte resection
Anterior Soft Tissue
PatternSynovitis, meniscoid lesion, capsular scarring
TreatmentArthroscopic debridement
Posterior Osseous
PatternOs trigonum or Stieda process
TreatmentEndoscopic excision
Posterior Soft Tissue
PatternFHL tendinopathy, capsulitis
TreatmentEndoscopic release
Critical Must-Knows
- Anterior impingement from tibial/talar spurs (osseous) or synovitis (soft tissue) limiting dorsiflexion
- Posterior impingement from os trigonum or FHL tendinitis limiting plantarflexion (dancers)
- Conservative management 53% success; osseous lesions less likely to respond than soft tissue
- Arthroscopic treatment 85-95% success with low complication rates (nerve injury 2-5%)
- Combined pathology common in posterior impingement - always assess for FHL involvement
Examiner's Pearls
- "Os trigonum syndrome = bone marrow edema on MRI confirms symptomatic lesion
- "FHL tendinitis coexists in 40-60% of posterior impingement cases
- "Anterior portals: anteromedial (saphenous nerve) and anterolateral (superficial peroneal nerve)
- "Posterior portals: posteromedial and posterolateral (sural nerve at risk)
Exam Warning
Clinical Distinction
Anterior: Dorsiflexion pain (Footballers). Posterior: Plantarflexion pain (Dancers).
Safety - Nerves at Risk
Anterior: Superficial Peroneal (SPN) - anterolateral portal. Posterior: Sural (posterolateral) and Tibial (posteromedial).
Surgical Technique
Anterior: Osteophyte Resection (burr). Posterior: Os Trigonum Excision + FHL Release.
Pathology
Anterior: Osseous spur or soft tissue. Posterior: Osseous (Os Trigonum) or FHL stenosing tenosynovitis.
Key Mnemonics
Mnemonic
PALSAnkle Impingement Types
P
Posterior (os trigonum)
Plantarflexion pain, dancers, posterior structures
A
Anterior (footballer's ankle)
Dorsiflexion pain, athletes, tibiotalar spurs
L
Lateral (soft tissue)
Anterolateral ankle, post-injury meniscoid lesion
S
Syndesmotic (high ankle)
Tibiofibular impingement, post-injury or diastasis
Memory Hook:Your PALS get ankle impingement syndromes
Mnemonic
SPURAnterior Impingement Clinical Features
S
Soccer/sport pain
Kicking and dorsiflexion activities reproduce symptoms
P
Palpable tenderness
Anterior joint line tenderness on examination
U
Unable to dorsiflex
Reduced dorsiflexion range of motion
R
Reproduce with test
Forced passive dorsiflexion elicits characteristic pain
Memory Hook:Think of the anterior ankle SPUR causing impingement
Mnemonic
DANCERPosterior Impingement Features
D
Dorsal foot pain
Posterior ankle pain radiating to heel or plantar foot
A
Athletes (ballet/soccer)
High-risk sports with repetitive plantarflexion
N
Nutcracker test positive
Forced plantarflexion reproduces pain with palpation
C
Cannot en pointe
Inability to maintain extreme plantarflexion positions
E
Edema on MRI
Bone marrow edema in os trigonum indicates symptomatic
R
Relief with injection
Diagnostic injection provides temporary symptom relief
Memory Hook:Think of DANCER syndrome for posterior ankle impingement
Ankle Joint Anatomy Relevant to Impingement
Understanding normal anatomy and motion is essential to comprehend impingement pathology.
Anterior Ankle Anatomy
- Anterior recess: Capsular space between tibia and talus allowing dorsiflexion
- Tibial plafond margin: Anterior distal tibial edge, site of spur formation
- Talar neck: Anterior talus articulates with anterior tibia in dorsiflexion
- Anterior joint capsule: Becomes taut in dorsiflexion, site of synovitis
- Neurovascular structures: Deep peroneal nerve and anterior tibial vessels cross anteriorly
Anterior portal anatomy (arthroscopy):
- Anteromedial portal: Medial to tibialis anterior, lateral to saphenous nerve
- Anterolateral portal: Lateral to EDL, medial to superficial peroneal nerve branches
- Anterocentral portal: Between EHL and EDL, risk to deep peroneal nerve
Posterior Ankle Anatomy
- Posterior recess: Capsular space behind ankle joint, largest synovial space
- Posterior talar process: Medial and lateral tubercles with FHL groove between
- Os trigonum: Accessory ossicle posterior to talus (10-25% prevalence)
- Stieda process: Elongated lateral talar tubercle (unfused os trigonum)
- FHL tendon: Travels between talar tubercles, at risk during posterior procedures
Posterior portal anatomy (endoscopy):
- Posterolateral portal: Lateral border Achilles, anterior to sural nerve
- Posteromedial portal: Medial border Achilles, protects tibial nerve and vessels
- Working space: Behind ankle joint and superior to calcaneal tuberosity
Biomechanics of Impingement
Normal ankle dorsiflexion range where anterior structures approximate without impingement. Plantarflexion range where posterior structures may impinge between tibia and calcaneus. Extreme plantarflexion in ballet dancers maximally compresses posterior ankle structures.
Motion Dynamics
- Normal dorsiflexion: Anterior joint space opens, posterior space narrows
- Normal plantarflexion: Posterior space opens, anterior space closes
- Impingement mechanism: Hypertrophied tissue or bone caught during end-range motion
- Synovitis cascade: Repetitive impingement causes inflammation, further hypertrophy, worsening symptoms
Overview
Ankle impingement syndromes are common causes of chronic ankle pain in athletes and dancers, with anterior impingement accounting for 60-70% of cases and posterior impingement 30-40%. The condition affects approximately 3-5% of competitive athletes, with highest prevalence in soccer (footballer's ankle), ballet (dancer's syndrome), and volleyball. Male predominance (2:1) in anterior impingement relates to higher participation in contact sports, while posterior impingement shows equal gender distribution given ballet's demographics.
Pathophysiology
General Mechanism of Ankle Impingement
Ankle impingement occurs when soft tissue or osseous structures become trapped between bones during terminal motion, causing pain and functional limitation. The pathophysiology differs between anterior and posterior impingement:
Key Pathophysiological Concepts:
- Mechanical impingement: Physical entrapment of tissues at end-range motion
- Inflammatory cascade: Repetitive impingement causes synovitis, tissue hypertrophy, and worsening symptoms
- Osseous vs soft tissue: Osseous lesions from chronic trauma/degeneration; soft tissue from acute injury or inflammation
- Activity-specific: Pattern relates to sport demands (kicking = anterior, en pointe = posterior)
Anterior Impingement Mechanism:
- Repetitive forced dorsiflexion causes anterior capsular traction
- Tibial and talar osteophytes form at sites of capsular avulsion
- Soft tissue hypertrophy (synovitis, meniscoid lesion) after ankle sprains
Posterior Impingement Mechanism:
- Extreme plantarflexion compresses posterior structures between tibia and calcaneus
- Os trigonum (unfused secondary ossification center) or Stieda process becomes symptomatic
- FHL tendon can become entrapped in the posterior compartment
Clinical Presentation
Clinical presentation varies based on impingement type, with anterior impingement causing dorsiflexion-related symptoms and posterior impingement affecting plantarflexion activities.
Investigations
Standard Imaging Protocol
Plain Radiographs:
- Weight-bearing lateral: Essential first-line imaging for both types
- Anterior impingement: Tibial and talar osteophytes visible on lateral view
- Posterior impingement: Os trigonum or Stieda process visible posteriorly
- AP and mortise views: Rule out arthritis, loose bodies, other pathology
MRI Indications:
- Confirmation of symptomatic pathology (bone marrow edema indicates active disease)
- Soft tissue assessment (synovitis, meniscoid lesion, FHL tendinopathy)
- Differentiate incidental anatomical variants from symptomatic pathology
- Pre-operative planning to identify concurrent pathology
CT Scan:
- Large osteophytes requiring 3D planning for resection
- Complex osseous anatomy for surgical planning
- Assessment of articular surface integrity
Diagnostic Injection:
- Ultrasound-guided injection confirms impingement as pain generator
- Local anesthetic provides diagnostic information
- Corticosteroid may provide temporary therapeutic benefit
Anterior Impingement Pathophysiology
Anterior impingement results from osseous or soft tissue pathology limiting dorsiflexion.
Footballer's Ankle (Osseous)
- Mechanism: Repetitive forced dorsiflexion causes capsular avulsion and osteophyte formation
- Tibial spurs: Anterior distal tibia develops traction spurs from capsular pulling
- Talar spurs: Anterior talar neck develops spurs that articulate with tibial osteophytes
- Kissing lesions: Matching tibial and talar spurs that interlock during dorsiflexion
- Sports: Soccer (kicking), running, basketball (jumping), gymnastics
Soft Tissue Impingement
- Anterolateral soft tissue: Hypertrophied synovium or meniscoid lesion after ankle sprain
- Bassett's ligament: Fascial band from AITFL to talus, may become pathologic
- Synovitis: Chronic inflammation from repetitive impingement creates hypertrophic tissue
- Scarring: Post-traumatic fibrosis in anterior gutter after injury
- Distal fascicle AITFL: Anterior inferior tibiofibular ligament fascicle impingement
Classification Systems
Anterior Impingement Classification
| type | osseous | softTissue | symptoms | treatment |
|---|---|---|---|---|
| Grade 1 (Mild) | Small tibial or talar spurs less than 3 mm | Minimal synovitis, no meniscoid lesion | End-range dorsiflexion discomfort only | Conservative management usually successful |
| Grade 2 (Moderate) | Moderate spurs 3-5 mm, not yet kissing | Moderate synovitis or small meniscoid lesion | Pain with activities requiring dorsiflexion | May respond to conservative care or injection |
| Grade 3 (Severe) | Large spurs greater than 5 mm, kissing lesions | Severe synovitis, large meniscoid lesion | Rest pain, significant motion loss | Surgical debridement typically required |
| Grade 4 (Advanced) | Extensive osteophytes with articular damage | Dense fibrosis, loose bodies | Daily symptoms, marked functional limitation | Arthroscopic debridement, may progress to arthritis |
Risk Factors
- Soccer players: Kicking motion with forced dorsiflexion
- Runners: Repetitive dorsiflexion during push-off and landing
- Previous ankle sprains: Soft tissue hypertrophy and scarring
- Chronic ankle instability: Abnormal motion causing impingement
- High-impact sports: Basketball, volleyball, gymnastics
- Anatomical factors: Limited native dorsiflexion, tight Achilles
Anterior Impingement Clinical Features
History
- Pain location: Anterior ankle joint line, worse with dorsiflexion
- Timing: End-range dorsiflexion activities (kicking, squatting, stairs)
- Insidious onset: Gradual progression over months to years
- Previous injury: History of ankle sprain in 60-70% of soft tissue cases
- Sports impact: Reduced performance in kicking, jumping, cutting activities
- Morning stiffness: Common, improves with activity initially
Physical Examination
- Tenderness: Anterolateral or anteromedial joint line palpation
- Range of motion: Reduced dorsiflexion (normal 10-20 degrees)
- Impingement test: Forced passive dorsiflexion reproduces anterior pain
- Palpable spurs: Large osteophytes may be palpable anteriorly
- Swelling: Anterior ankle fullness from synovitis
- Gait: May have shortened stride or altered heel strike
Special tests:
- Anterior impingement test: Passive forced dorsiflexion with tibial translation elicits pain
- Molloy test: Palpation of anterolateral gutter with dorsiflexion and inversion
- Single leg squat: Pain at bottom of deep squat position
- Hop test: Pain with landing from single leg hop
Differential Diagnosis
- Ankle arthritis: Broader pain pattern, crepitus, may have impingement component
- Tibialis anterior tendinitis: More proximal, resisted dorsiflexion painful
- Chronic ankle instability: Positive anterior drawer, lateral joint line tenderness
- Stress fracture: Point tenderness over bone, positive tuning fork test
- Syndesmotic injury: High ankle pain, squeeze test positive
Posterior Impingement Pathophysiology
Posterior impingement occurs from compression of structures between tibia, talus, and calcaneus during plantarflexion.
Os Trigonum Syndrome
- Anatomy: Accessory ossicle posterior to lateral talar tubercle
- Prevalence: Present in 10-25% of population (bilateral in 50% of those affected)
- Pathologic mechanism: Becomes symptomatic from repetitive compression or synchondrosis injury
- Nutcracker effect: Os compressed between tibia and calcaneus in plantarflexion
- FHL involvement: Tendinitis may coexist from adjacent inflammation
Stieda Process
- Definition: Elongated lateral talar tubercle (unfused os trigonum)
- Fracture: Can fracture at junction with talus (Shepherd fracture)
- Impingement: Functions similarly to os trigonum causing posterior compression
- Imaging: Appears as elongated posterior process on lateral radiograph
Soft Tissue Impingement
- Posterior capsule: Hypertrophic synovitis from repetitive compression
- FHL tendinopathy: Tenosynovitis from adjacent inflammation or direct compression
- Posterior talofibular ligament: Thickened ligament may contribute to symptoms
- Posterior intermalleolar ligament: Hypertrophy from chronic loading
Dancer's Syndrome
Special consideration for ballet dancers:
- En pointe position: Extreme plantarflexion (90+ degrees) maximally narrows posterior space
- Relevé repetition: Thousands of repetitions weekly in professional dancers
- FHL involvement: Concurrent FHL tendinitis in 40-60% of cases
- Career impact: May be career-ending if conservative management fails
Risk Factors
Prevalence of os trigonum in general population, small fraction become symptomatic. Ballet dancers with posterior ankle pain have coexistent FHL tendinopathy requiring treatment. En pointe position requires extreme plantarflexion compressing posterior structures maximally.
High-risk activities:
- Ballet dancing (especially en pointe work)
- Soccer (plantarflexion during kicking follow-through)
- Downhill running (repetitive plantarflexion)
- Gymnastics (landing positions)
- Figure skating (toe pointing during jumps)
Posterior Impingement Clinical Features
History
- Pain location: Posterior ankle, may radiate to heel or plantar foot
- Character: Deep aching pain, worse with plantarflexion activities
- Onset: Gradual in athletes, may be acute after forced plantarflexion injury
- Activities: En pointe (dancers), kicking (soccer), downhill running
- Functional loss: Cannot maintain extreme plantarflexion positions
- FHL symptoms: Triggering or weakness if concurrent tendinopathy
Physical Examination
- Tenderness: Posterior ankle, lateral or medial to Achilles tendon
- Range of motion: Pain at end-range plantarflexion
- Posterior impingement test: Forced passive plantarflexion reproduces pain
- Palpable os trigonum: May feel prominence posterior to talus
- FHL assessment: Check for triggering, weakness, stretch test positive
Special tests:
- Posterior impingement test: Passive forced plantarflexion elicits posterior pain
- Nutcracker test: Palpate os trigonum while passively plantarflexing ankle
- FHL stretch test: Dorsiflexion with hallux extension (positive if concurrent FHL issue)
- Resisted plantarflexion: Usually pain-free (differentiates from Achilles pathology)
Imaging Findings
Imaging Modalities for Posterior Impingement
| modality | findings | utility | limitations |
|---|---|---|---|
| Lateral Radiograph | Os trigonum or Stieda process visible posterior to talus | Initial screening, confirms osseous pathology | Cannot assess soft tissue or bone edema |
| MRI | Bone marrow edema in os trigonum, joint effusion, FHL tenosynovitis | Differentiates symptomatic from incidental os trigonum, shows soft tissue | Static images, cannot assess dynamic impingement |
| CT | 3D reconstruction of os trigonum size and position, synchondrosis detail | Pre-operative planning for bone excision | Poor soft tissue detail, radiation exposure |
| Ultrasound | Dynamic FHL assessment, posterior soft tissue thickening | Dynamic evaluation, can guide injection | Operator dependent, limited bone detail |
| Bone Scan | Increased uptake in symptomatic os trigonum | Confirms symptomatic versus incidental finding | Non-specific, radiation, rarely used now with MRI available |
Diagnostic Injection
- Technique: Posterior ankle injection with local anesthetic under ultrasound guidance
- Targets: Peri-os trigonum region or posterior joint recess
- Interpretation: Significant pain relief confirms posterior impingement as pain generator
- Therapeutic: May add corticosteroid for temporary symptom relief
- Caution: Avoid FHL tendon sheath (rupture risk with steroid)
Management
📊 Management Algorithm
Click to expand
Initial management is conservative for both anterior and posterior impingement.
Activity Modification
- Relative rest: Reduce or eliminate aggravating activities 4-8 weeks
- Cross-training: Maintain fitness with low-impact alternatives (swimming, cycling)
- Sport modification: Avoid extreme dorsiflexion (anterior) or plantarflexion (posterior)
- Gradual return: Progressive loading protocol over 8-12 weeks
- Technique adjustment: Biomechanical correction to reduce impingement forces
Immobilization
- CAM boot: 2-4 weeks for severe acute symptoms
- Position: Neutral ankle position to reduce end-range compression
- Duration: Minimum necessary to avoid stiffness (2-4 weeks maximum)
- Gradual weaning: Transition to supportive athletic taping
Pharmacological Interventions
- NSAIDs: Oral (naproxen 500 mg BD) or topical for 2-4 week courses
- Analgesics: Paracetamol for pain control without inflammation
- Ice therapy: 15-20 minutes multiple times daily for acute symptoms
- Topical treatments: Anti-inflammatory gels or patches
Most patients require 3-6 months of conservative management before considering surgical intervention.
Surgical Management
Indications and Pre-Operative Planning
Surgical Indications
- Failed conservative management: Minimum 3-6 months appropriate non-operative treatment
- Persistent symptoms: Pain limiting daily activities or sports participation
- Mechanical symptoms: Locking, catching suggesting loose body or meniscoid lesion
- Professional athletes: Earlier surgery for career impact (after 6-12 weeks conservative trial)
- Large osteophytes: Grade 3-4 osseous impingement unlikely to respond conservatively
- Documented pathology: MRI confirmation of structural lesion amenable to surgery
Pre-Operative Assessment
- MRI review: Identify all pathology (osseous, soft tissue, concurrent issues)
- Patient expectations: Realistic goals for return to high-level activity
- Optimize health: Address smoking, weight, inflammatory conditions
- Surgical planning: Anterior versus posterior approach, arthroscopy versus open
- Equipment check: Ensure appropriate arthroscopy equipment and instrumentation available
Arthroscopic Techniques
Anterior Ankle Arthroscopy for Anterior Impingement
Patient Positioning:
- Supine position on operating table
- Thigh tourniquet (250-300 mmHg)
- Non-invasive distraction (10 lbs) OR invasive distraction with pins
- Ankle in neutral position with bump under ipsilateral hip
Portal Placement:
- Anteromedial portal: 1 cm medial to tibialis anterior tendon at joint line
- Anterolateral portal: Just lateral to peroneus tertius tendon at joint line
- Mark superficial peroneal nerve branches before portals (dorsiflexion makes visible)
- Anterocentral portal rarely needed (deep peroneal nerve risk)
Systematic Inspection:
- 30-degree arthroscope through anteromedial portal initially
- Inspect entire joint: medial gutter, central dome, lateral gutter
- Identify pathology: osteophytes, synovitis, meniscoid lesion, cartilage damage
- Document findings with photographs/video
- Switch arthroscope to anterolateral portal for medial inspection
Debridement Technique:
1. Synovectomy:
- Use arthroscopic shaver to remove hypertrophic synovium
- Debride anterolateral soft tissue impingement (meniscoid lesion)
- Excise thickened Bassett's ligament if contributing
- Create smooth joint surfaces free of catching tissue
2. Osteophyte Resection:
- Use arthroscopic burr for bone removal
- Tibial osteophytes: resect from medial to lateral across anterior plafond
- Talar osteophytes: carefully remove from talar neck/dome
- Goal: restore smooth tibiotalar articulation
- Avoid excessive bone removal (weakens joint)
- Irrigate frequently to clear debris and improve visualization
3. Cartilage Management:
- Assess for kissing lesions or chondral damage
- Debride unstable cartilage flaps to stable edges
- Microfracture for focal full-thickness defects if appropriate
- Document extent of arthritis for prognosis
4. Confirm Decompression:
- Test ankle dorsiflexion under direct visualization
- Ensure no residual impingement of bone or soft tissue
- Remove all loose bodies or debris
- Final inspection of entire joint
Closure:
- Remove instruments and deflate distraction
- Close portals with single nylon suture or skin adhesive
- Apply soft compressive dressing
- Posterior splint in neutral if significant bone work
Post-Operative Protocol:
- 0-2 weeks: NWB in boot if extensive bone work, otherwise WBAT
- 2-6 weeks: Progressive weight-bearing, gentle AROM exercises
- 6-12 weeks: Strengthening, proprioception training
- 3-4 months: Return to sport-specific training
- 4-6 months: Full unrestricted activity typically achieved
The superficial peroneal nerve branches cross the anterior ankle and are at highest risk during anterolateral portal placement. Mark the nerve branches pre-operatively with ankle dorsiflexion and eversion. The deep peroneal nerve and anterior tibial vessels are at risk with anterocentral portal - avoid if possible. Excessive osteophyte resection can destabilize the ankle joint.
Surgical Complications
Intraoperative Complications
Complications by Approach
| complication | anteriorArthroscopy | posteriorEndoscopy | openSurgery | management |
|---|---|---|---|---|
| Nerve Injury | Superficial peroneal (2%), deep peroneal (less than 1%) | Sural (2%), tibial (less than 1%) | Higher rates (5-8%), same nerves at risk | Most resolve spontaneously, neuroma excision if painful |
| Vascular Injury | Anterior tibial artery (rare, less than 0.5%) | Posterior tibial vessels (rare, less than 0.5%) | Higher risk with open dissection | Immediate vascular surgery consultation if identified |
| FHL Tendon Injury | Not applicable | Laceration or scarring (1-2%) | Similar risk (1-2%) | Repair if identified, may need FHL release or transfer |
| Incomplete Resection | Residual osteophytes (3-5%) | Incomplete os trigonum excision (2-4%) | Lower risk with direct visualization | Revision surgery if symptomatic, confirm on imaging |
Post-Operative Complications
- Infection: 1-2% arthroscopy, 3-5% open surgery
- Stiffness: More common after anterior procedures and with prolonged immobilization
- Recurrence: 5-10% may have persistent or recurrent symptoms
- CRPS: Rare (less than 1%) but devastating complication
- Arthrofibrosis: Excessive scar formation limiting motion
- Wound problems: Delayed healing, dehiscence more common in open procedures
Failure Management
Diagnostic approach:
- Repeat imaging (CT or MRI) to assess adequacy of resection
- Consider alternative diagnoses (arthritis, instability, tarsal coalition)
- Assess rehabilitation compliance and progression
- Diagnostic injection to confirm pain generator
Revision surgery indications:
- Confirmed incomplete osteophyte resection on CT
- Residual os trigonum fragment on imaging
- Progressive symptoms despite appropriate rehabilitation
- New pathology identified (arthritis, loose body)
Revision technique:
- May require open approach after failed arthroscopy for better visualization
- More aggressive debridement of residual pathology
- Address any concurrent pathology missed initially
- Consider salvage options if severe arthritis present (fusion, arthroplasty)
Complications
Arthroscopic Procedure Complications
Nerve Injury (1-5%):
- Superficial peroneal nerve: most common with anterolateral portal
- Sural nerve: risk with posterolateral portal
- Tibial nerve: rare, posterolateral approach
- Prevention: portal placement under direct vision, mark superficial peroneal nerve preoperatively
Vascular Injury (less than 1%):
- Anterior tibial artery: anterior approach
- Posterior tibial artery: posterior approach
- Prevention: avoid deep aggressive resection, know safe zones
Tendon Injury:
- FHL: highest risk during posterior procedures (4-7% transient weakness)
- Tibialis anterior: anterior approach
- Prevention: protect FHL during os trigonum excision, visualize tendons
Instrument Breakage:
- Burr or shaver blade breakage in joint
- Management: immediate arthroscopic retrieval
Infection (less than 1%):
- Superficial wound infection: oral antibiotics
- Deep joint infection: rare, requires washout
Condition-Specific Complications
Recurrence of Impingement (5-15%):
- Incomplete resection of pathology
- Reformation of scar tissue
- Management: revision arthroscopy vs open procedure
Ankle Instability:
- Excessive lateral ligament release during anterior debridement
- Prevention: preserve ATFL fibers during capsular work
Progression to Arthritis:
- Pre-existing cartilage damage may progress despite successful debridement
- Higher risk with Scranton Grade 3-4 lesions
Postoperative Care
Immediate Postoperative (0-2 Weeks)
Weight Bearing:
- Anterior arthroscopy: Weight bear as tolerated in protective boot
- Posterior endoscopy: Protected weight bearing for 2 weeks
- Os trigonum excision: Partial weight bearing for 2 weeks
Wound Care:
- Keep dressings dry for 48-72 hours
- Portal wounds: steri-strips, minimal suturing
- Compression bandage to minimize swelling
Early Mobilization:
- Ankle pumps and gentle ROM from day 1
- Ice and elevation to control swelling
- DVT prophylaxis per surgeon preference (aspirin typically adequate for low-risk patients)
Rehabilitation Phase (2-6 Weeks)
Physiotherapy Initiation:
- Formal physiotherapy from week 2
- ROM exercises: full dorsiflexion/plantarflexion goals
- Scar mobilization at portal sites
- Proprioceptive training: wobble board progression
Strengthening:
- Week 2-4: isometric exercises
- Week 4-6: progressive resistance (theraband)
- Calf strengthening: eccentric loading progression
Return to Activity (6-12 Weeks)
Sport-Specific Rehabilitation:
- Week 6-8: jogging on flat surfaces
- Week 8-10: sport-specific drills
- Week 10-12: return to training (non-contact)
- Week 12+: return to full competition
Dancers (Ballet):
- Anterior: relevé progression from week 6
- Posterior: en pointe work from week 8-10 (os trigonum excision)
- Full performance: 3-4 months anterior, 3-5 months posterior
Follow-Up Schedule
- 2 weeks: wound check, suture removal if needed
- 6 weeks: clinical review, progress assessment
- 3 months: final review for straightforward cases
- 6-12 months: if persistent symptoms or elite athletes
Outcomes and Return to Sport
Success Rates by Procedure
Anterior arthroscopic debridement achieves good-to-excellent outcomes in appropriately selected patients.
Posterior endoscopic os trigonum excision with high success rates, best for isolated posterior pathology.
Return to pre-injury sport level achievable in most athletes with appropriate rehabilitation.
Return to Sport Timeline
Sport-Specific Return Timeline
| sport | anteriorImpingement | posteriorImpingement | prognosis |
|---|---|---|---|
| Ballet (Professional) | 4-6 months to full performance | 3-5 months to en pointe work | Excellent if isolated pathology, may need technique modification |
| Soccer | 3-5 months to competitive play | 2-4 months to competitive play | Greater than 85% return to pre-injury level |
| Distance Running | 3-4 months to racing | 2-3 months to racing | Greater than 90% return to full training |
| Basketball/Volleyball | 4-6 months to competitive play | 3-4 months to competitive play | Good return but may have reduced vertical jump initially |
Prognostic Factors
Favorable outcomes:
- Isolated anterior or posterior impingement (not combined pathology)
- No significant arthritis at time of surgery
- Young active patient with good rehabilitation compliance
- Complete resection of pathology at surgery
- Early intervention (symptom duration less than 2 years)
Poor prognostic factors:
- Concurrent moderate-severe ankle arthritis
- Combined anterior and posterior pathology
- Chronic symptoms (greater than 5 years duration)
- Previous ankle fracture or surgery
- Worker's compensation or litigation
- Smoking, diabetes, inflammatory arthropathy
Evidence Base
Conservative Management of Ankle Impingement
Ferguson D, et al. • Am J Sports Med (2018)
Key Findings:
- 142 athletes with ankle impingement treated conservatively for 3+ months
- Overall 53% achieved good-to-excellent outcomes avoiding surgery
- Anterior soft tissue impingement: 67% success vs osseous anterior (41%) or posterior (45%)
- Professional athletes: 38% success vs recreational athletes (61%)
Clinical Implication: Conservative management more effective for anterior soft tissue impingement; osseous and posterior impingement more likely to require surgery.
Limitation: Single-center study; selection bias towards motivated athletes.
Arthroscopic Treatment of Ankle Impingement
Zwiers R, et al. • J Bone Joint Surg Am (2020)
Key Findings:
- Systematic review of 47 studies (2,847 patients) on arthroscopic treatment
- Anterior impingement: 88% good-to-excellent outcomes, 82% return to sport
- Posterior endoscopic os trigonum excision: 91% good-to-excellent, 89% return to sport
- Complication rate: 4.2% anterior (nerve injury 1.8%), 3.7% posterior (nerve injury 2.1%)
Clinical Implication: Arthroscopic treatment highly effective for both anterior and posterior impingement with low complication rates.
Limitation: Heterogeneous outcome measures across studies; limited long-term follow-up.
Long-Term Outcomes After Impingement Surgery
Kennedy JG, et al. • Foot Ankle Int (2021)
Key Findings:
- 156 patients with minimum 5-year follow-up after arthroscopic impingement surgery
- AOFAS scores improved from 58 pre-op to 88 at final follow-up
- 84% returned to desired sport level; 76% achieved pre-injury performance
- Anterior soft tissue 91% vs osseous 79% success; posterior 93% overall success
Clinical Implication: Arthroscopic treatment provides durable long-term outcomes with high patient satisfaction.
Limitation: Retrospective design; single-surgeon series may limit generalizability.
Posterior Endoscopy for Os Trigonum Syndrome
Scholten PE, Sierevelt IN, et al. • Knee Surg Sports Traumatol Arthrosc (2015)
Key Findings:
- 55 consecutive patients with os trigonum syndrome treated with posterior endoscopy
- 91% good-to-excellent outcomes at mean 2.8-year follow-up
- Return to sport at 10.4 weeks (range 6-24 weeks); 89% returned to pre-injury level
- Complication rate 5.5% (2 transient sural nerve paresthesias, 1 wound infection)
Clinical Implication: Posterior endoscopy is safe and effective for os trigonum excision with rapid return to sport.
Limitation: No comparison group; all patients were athletes with high motivation for recovery.
Exam Viva Scenarios
Practice these scenarios to excel in your viva examination
VIVA SCENARIOStandard
Scenario 1: Footballer with Anterior Impingement
EXAMINER
"A 24-year-old semi-professional soccer player presents with 18 months of progressive anterior ankle pain. He describes pain when kicking the ball and during deep squatting drills. He has had 4 months of physiotherapy and two corticosteroid injections with temporary relief only. Examination reveals anterolateral joint line tenderness, reduced dorsiflexion to 5 degrees (normal 15 degrees contralateral), and pain with forced dorsiflexion. Weight-bearing lateral radiograph shows 6 mm tibial and talar osteophytes with kissing lesions. MRI confirms moderate anterior impingement with grade 2 cartilage changes but no significant arthritis."
EXCEPTIONAL ANSWER
This is footballer's ankle with osseous anterior impingement causing mechanical symptoms and functional limitation. The 18-month duration, failed conservative management including injections, and large kissing osteophytes make this an excellent surgical candidate. Anterior ankle arthroscopy with osteophyte resection is indicated to restore motion and allow return to sport.
KEY POINTS TO SCORE
Diagnosis: Footballer's ankle with grade 3 osseous anterior impingement (osteophytes greater than 5 mm)
Failed conservative treatment: 4 months physio and 2 injections indicates appropriate trial
Mechanical symptoms: Reduced dorsiflexion and kissing lesions suggest mechanical block
Surgical indication: Young athlete with career impact, failed conservative care, amenable pathology
Arthroscopic technique: Anterior portals, systematic inspection, osteophyte resection with burr
Concomitant pathology: Grade 2 cartilage changes acceptable, debride if unstable
Expected outcome: 85-90% success rate, return to soccer 3-5 months
Counseling: Small risk of incomplete relief if arthritis progresses, may need revision
COMMON TRAPS
✗Not recognizing that conservative management has failed adequately - he needs surgery
✗Offering more injections which will not help with large mechanical osteophytes
✗Recommending open surgery when arthroscopy is preferred approach
✗Promising 100% return to pre-injury level - realistic expectation is 80-85% for his sport level
✗Not discussing cartilage changes which may limit long-term outcomes
✗Inadequate post-operative protocol - needs 3-4 months before return to contact sport
LIKELY FOLLOW-UPS
"Walk me through your portal placement and neurological structures at risk"
"During arthroscopy you find the osteophytes are larger than expected and there is moderate cartilage damage - does this change your management?"
"Describe your osteophyte resection technique to avoid excessive bone removal"
"What is your post-operative protocol and when do you allow him to return to kicking?"
"At 6 months post-op he has recurrent pain - how do you evaluate and manage this?"
VIVA SCENARIOStandard
Scenario 2: Ballet Dancer with Posterior Impingement
EXAMINER
"A 19-year-old professional ballet dancer presents with 12 months of posterior ankle pain preventing en pointe work. She describes deep aching pain during plantarflexion that has progressively worsened. She occasionally feels triggering with great toe flexion. Examination shows posterior ankle tenderness lateral to Achilles, painful forced plantarflexion, and positive FHL stretch test with triggering. MRI demonstrates os trigonum with bone marrow edema, posterior joint effusion, and FHL tenosynovitis in zone 1. She has a major audition in 4 months and asks if surgery can get her ready in time."
EXCEPTIONAL ANSWER
This is os trigonum syndrome with concurrent FHL tendinitis in a professional ballet dancer, a complex scenario requiring combined treatment of both pathologies and realistic timeline counseling. The coexistence of FHL pathology requires addressing both issues surgically for optimal outcome. However, 4 months is borderline insufficient for return to professional-level en pointe work.
KEY POINTS TO SCORE
Diagnosis: Os trigonum syndrome with concurrent FHL zone 1 tendinopathy (40-60% coexist in dancers)
Bone marrow edema: Confirms symptomatic os trigonum not incidental finding
Combined pathology: Must address both os trigonum AND FHL for successful outcome
Surgical approach: Posterior endoscopy for os trigonum excision AND FHL release
Timeline concern: 4 months borderline for return to professional en pointe (typically need 4-6 months)
Realistic counseling: May miss audition or perform suboptimally, discuss postponing surgery
Technique: Prone positioning, posterolateral/posteromedial portals, excise os trigonum, release FHL tunnel
Expected outcome: 90-95% success for os trigonum, 85-90% for FHL, but recovery takes time
COMMON TRAPS
✗Promising she will be ready in 4 months when 4-6 months is realistic minimum
✗Not recognizing and addressing the concurrent FHL pathology will lead to failure
✗Treating only FHL and ignoring os trigonum will result in persistent symptoms
✗Recommending open surgery when endoscopic approach preferred (faster recovery)
✗Not discussing career implications - professional ballet very demanding, success rates lower
✗Failing to counsel about risk of career-ending outcome if severe pathology found at surgery
LIKELY FOLLOW-UPS
"Describe your endoscopic technique for combined os trigonum excision and FHL release"
"How do you protect the neurovascular structures during posterior endoscopy?"
"At surgery you find a very large os trigonum that is difficult to remove endoscopically - what are your options?"
"If she insists on proceeding with surgery to make the audition, what do you tell her?"
"At 3 months post-op she has good pain relief but still has mild FHL triggering - what is your management?"
MCQ Practice Points
Os Trigonum Syndrome
Q: What MRI finding confirms a symptomatic os trigonum versus incidental finding? A: Bone marrow edema within the os trigonum indicates active inflammation and symptomatic impingement. Os trigonum is present in 10-25% of population - most are asymptomatic. MRI showing edema within the ossicle, along with posterior ankle effusion, confirms the diagnosis.
Portal Anatomy
Q: What nerve is at greatest risk during anterior ankle arthroscopy and how is it protected? A: Superficial peroneal nerve is at greatest risk (crosses anterolateral portal path in 5-28% of patients). Protect by: (1) marking nerve course before incision, (2) making incision with blade perpendicular to skin only, (3) spreading subcutaneously with hemostat.
FHL Tendinopathy
Q: In what percentage of posterior impingement cases does FHL tendinitis coexist? A: 40-60% of posterior ankle impingement cases have concurrent FHL tendinopathy, particularly in ballet dancers. Both must be addressed surgically for optimal outcome - failure to release FHL will result in persistent symptoms despite os trigonum excision.
Conservative Success Rates
Q: What type of ankle impingement has the best response to conservative management? A: Anterior soft tissue impingement has 67% success with conservative treatment (vs 41% for osseous anterior and 45% for posterior). Conservative measures include activity modification, NSAIDs, physiotherapy, and corticosteroid injections for 3-6 months trial.
Osteophyte Classification
Q: What is the Scranton and McDermott classification for anterior tibiotalar osteophytes? A: Grade 1: Less than 3mm tibial spur. Grade 2: 3-5mm tibial spur without talar involvement. Grade 3: Greater than 5mm tibial spur with secondary talar spur. Grade 4: Pantalar arthritic changes. Grades 3-4 require surgical intervention; Grade 4 may need fusion rather than debridement.
Australian Context
Private Health Insurance
- Day surgery or overnight stay depending on complexity
- Gap fees variable: $500-$2000 for arthroscopic procedures
- Anterior and posterior scopes can be combined in one session
Public Hospital Access
- Generally Category 2 (semi-urgent) for symptomatic impingement
- Wait times: 60-180 days depending on jurisdiction
- Elite/professional athletes may receive expedited care
Sports Medicine Network
- Australian Institute of Sport (AIS) referral pathways for elite athletes
- State sports institutes (WAIS, NSWIS, etc.) have integrated orthopaedic services
- Sports medicine physicians often manage conservatively before surgical referral
PBS Considerations
- NSAIDs: widely available, OTC or PBS subsidised
- Corticosteroid injections: not PBS subsidised, patient cost
- Therapeutic Goods Administration: ultrasound-guided injection preferred for accuracy
Common Australian Presentations
- High incidence in ballet dancers (Australian Ballet, state companies)
- Football codes: AFL, rugby union, rugby league, soccer
- Distance runners: high participation rates in Australia
- Beach sports: volleyball, surfing contributing to ankle pathology
Ankle Impingement Syndromes Exam Essentials
High-Yield Exam Summary
Must-Know Anatomy
- •Anterior portals: anteromedial (medial to TA), anterolateral (lateral to EDL/PT)
- •Posterior portals: posterolateral and posteromedial, 1-2 cm proximal to superior calcaneus
- •Superficial peroneal nerve: crosses anterior ankle, mark before anterolateral portal
- •Os trigonum: posterior to talus, present 10-25% population, bilateral 50% of cases
- •FHL tendon: between talar tubercles, at risk during posterior procedures
Anterior vs Posterior Features
- •ANTERIOR: dorsiflexion pain, soccer/running, tibiotalar spurs (footballer's ankle)
- •POSTERIOR: plantarflexion pain, ballet/soccer, os trigonum (dancer's syndrome)
- •Anterior test: forced passive dorsiflexion reproduces pain
- •Posterior test: forced passive plantarflexion (nutcracker test) elicits pain
- •Imaging: lateral XR shows osseous pathology, MRI shows soft tissue and edema
Conservative Management
- •Activity modification 3-6 months first-line treatment
- •NSAIDs and physiotherapy addressing contributing factors
- •Corticosteroid injection: 40-60% temporary relief, max 2-3 injections
- •Success rates: 50-60% anterior (better soft tissue), 40-50% posterior
- •Predictors of failure: large osteophytes (greater than 5 mm), mechanical symptoms, professional athletes
Surgical Indications
- •Failed 3-6 months appropriate conservative treatment
- •Persistent symptoms limiting activities or sport participation
- •Large osteophytes (greater than 5 mm) or symptomatic os trigonum on imaging
- •Professional athletes after 6-12 weeks conservative trial
- •Mechanical symptoms (locking, catching) suggesting structural lesion
Arthroscopic Technique Pearls
- •ANTERIOR: supine, non-invasive distraction, AM/AL portals, shaver for synovium, burr for osteophytes
- •POSTERIOR: prone position, posterolateral/posteromedial portals, excise os trigonum, protect FHL
- •Superficial peroneal nerve: anterolateral portal risk, mark pre-op with dorsiflexion
- •Tibial nerve: posteromedial portal risk, stay posterior and use blunt dissection
- •Complete resection: confirm no residual impingement with ROM testing under visualization
Viva Traps
- •Don't rush to surgery - 3-6 months conservative trial required unless professional athlete
- •Recognize concurrent FHL pathology in posterior impingement (40-60% coexist in dancers)
- •Endoscopic approach preferred when available: faster recovery, lower complications
- •Realistic timeline: 3-4 months anterior, 2-3 months posterior to return to sport
- •Professional ballet dancers: 4-6 months to en pointe, technique modification may be needed
Critical Numbers
- •Osteophyte size: less than 3 mm (mild), 3-5 mm (moderate), greater than 5 mm (severe requiring surgery)
- •Conservative success: 50-60% anterior, 40-50% posterior with appropriate treatment
- •Surgical success: 85-90% anterior, 90-95% posterior with endoscopic approach
- •Return to sport: 3-5 months anterior, 2-4 months posterior arthroscopy
- •Complication rate: 4% anterior, 3-4% posterior endoscopy (nerve injury most common)