Deltoid Ligament Injuries
Medial Ankle Stability | PER Mechanism | Rare Isolated Injury
Deltoid Injury Grading
Critical Must-Knows
- Deltoid complex 2-3x stronger than ATFL - isolated injury rare
- PER mechanism most common - associated with SER-4 fractures
- Medial clear space greater than 4mm indicates instability
- MRI gold standard for soft tissue assessment
- Conservative treatment 4-6 weeks for isolated injuries
Clinical Pearls
- "Deep layer critical for rotational and translational control
- "Superficial layer for valgus and eversion restraint
- "Always suspect associated syndesmosis injury or fractures
- "Surgery for fracture/syndesmosis fixation or chronic instability
Clinical Imaging
Imaging Gallery
Exam Warning
High-Yield Mechanisms
Focus on PER vs PAB mechanics. Isolated deltoid injury is rare (3-5%)—always suspect associated syndesmosis injury or fractures.
Key Concepts
Master Medial Clear Space interpretation (greater than 4mm) and defend Surgical vs Conservative indications (fracture/instability vs isolated).
Anatomic Foundation
Deltoid Ligament Complex Structure
The deltoid ligament is a multifascicular triangular structure extending from the medial malleolus to the tarsal bones, providing primary medial ankle stability.
Superficial Deltoid Components
Tibionavicular ligament: Anterior colliculus to navicular tuberosity Tibiocalcaneal ligament (superficial): Anterior colliculus to sustentaculum tali Tibiospring ligament: Anterior colliculus to superomedial calcaneonavicular (spring) ligament Posterior superficial tibiotalar: Posterior colliculus to medial talus Collective function: Primary restraint to hindfoot valgus and eversion Width: Fan-shaped, broad insertion covering medial hindfoot Thickness: Thinner than deep layer (1-2mm average)
Deep Deltoid Components
Anterior tibiotalar ligament: Intercollicular groove to medial talus anterior Posterior tibiotalar ligament (deep): Posterior intercollicular region to medial talar tubercle Tibiocalcaneal ligament (deep): Intercollicular groove to calcaneal medial wall Collective function: Critical restraint to external rotation, prevents lateral talar translation Configuration: Thick cord-like bands (3-5mm thickness) Strongest component: Posterior tibiotalar (deep) with tensile strength 800-1200N Critical for stability: Deep layer injury indicates severe force and high risk associated injuries
Neurovascular Relationships
Posterior tibial neurovascular bundle: 1-1.5cm posterior to medial malleolus, deep to flexor retinaculum Medial plantar nerve branch: Emerges at sustentaculum level, innervates FHB Saphenous nerve: Anterior to deltoid, accompanies great saphenous vein Arterial supply: Medial malleolar branches from posterior tibial artery Venous drainage: Great saphenous vein system medially Surgical relevance: Structures at risk during surgical approaches to medial ankle
Biomechanical Function and Load Distribution
At a Glance
Deltoid ligament injuries are uncommon (3-5% of ankle sprains) because the deltoid complex is 2-3 times stronger than the ATFL (tensile strength 800-1200N). Injuries are graded I-III based on fiber disruption and typically occur with pronation-external rotation mechanisms, often associated with lateral malleolar fractures (SER-4) or syndesmotic disruption. The deltoid has superficial (resists hindfoot valgus/eversion) and deep (resists external rotation and lateral talar translation) components. Diagnosis requires clinical suspicion, positive external rotation stress test, and medial clear space over 4mm on weight-bearing radiographs. MRI is gold standard for soft tissue assessment. Isolated injuries are treated conservatively (4-6 weeks immobilisation, 70-80% success); surgical repair is reserved for injuries requiring fracture/syndesmosis fixation or chronic instability.
Mnemonic
Hook:REVEL
The deltoid complex contributes 40-50% of total ankle stability with intact osseous anatomy, increasing to 70-80% when bony congruity compromised. Tensile strength of intact deltoid is 2-3 times greater than ATFL (deltoid 800-1200N vs ATFL 300-400N), explaining rarity of isolated injuries.
Load distribution varies with ankle position. In neutral position, deep posterior tibiotalar bears maximum load. In dorsiflexion, anterior tibiotalar and superficial components engage. In plantarflexion, posterior components maximally stressed. This position-dependent loading explains injury patterns based on mechanism.
Injury Classification and Mechanisms
Grading System
Deltoid ligament injuries are graded based on extent of fiber disruption and functional impairment, assessed clinically and with advanced imaging.
Deltoid Ligament Injury Grading Classification
| feature | clinicalFindings | imagingFindings | functionalImpact | treatment | prognosis |
|---|---|---|---|---|---|
| Grade 1 (Sprain/Strain) | Mild medial ankle tenderness, minimal swelling, no instability on stress testing | MRI: Ligament intact with surrounding edema, no fiber disruption. Radiographs normal | Able to weight-bear with discomfort, normal ROM with pain at extremes | Conservative: protection 2-3 weeks, early ROM | Excellent, 90% full recovery 4-6 weeks |
| Grade 2 (Partial Tear) | Moderate-severe tenderness, ecchymosis, mild instability on external rotation stress | MRI: Partial thickness tear with some fiber continuity. May show slight medial clear space widening (less than 4mm) | Difficulty weight-bearing, painful ROM, subjective instability | Conservative: CAM boot immobilization 4-6 weeks, protected weight-bearing | Good, 70-80% full recovery 8-12 weeks, 20% chronic symptoms |
| Grade 3 (Complete Rupture) | Severe tenderness, extensive ecchymosis to hindfoot, positive instability tests, often associated injuries | MRI: Complete ligament discontinuity, fluid in ligament gap. Radiographs: medial clear space greater than 4mm, possible fracture | Unable to weight-bear, gross instability on examination, significant functional limitation | Variable: Conservative if isolated, surgical if associated syndesmosis/fracture | Fair-good, 60-70% recovery conservative, 80-85% with appropriate surgical treatment |
Injury Mechanisms and Force Patterns
Pronation-External Rotation (PER): Most common mechanism for deltoid injury. Sequential failure pattern:
- Deltoid ligament rupture (medial structure fails first)
- Anterior syndesmosis disruption (AITFL tear)
- Posterior syndesmosis disruption or posterior malleolus fracture
- Fibula fracture at level of syndesmosis (Weber B or C)
This represents SER-4 pattern in Lauge-Hansen classification. Deltoid injury indicates high energy and mandates syndesmotic assessment.
Pronation-Abduction (PAB): Less common but classic fracture pattern:
- Deltoid rupture OR transverse medial malleolus fracture
- Lateral malleolus fracture (transverse or comminuted, at level of plafond)
- Usually syndesmosis intact
Medial malleolus fracture may occur instead of deltoid rupture depending on bone quality (osteoporotic bone fractures rather than ligament tears).
Direct Valgus Trauma: Rare isolated deltoid injury from pure valgus force without rotation. More common in sports with lateral impact (soccer, rugby). Usually partial tears of superficial layer, deep layer remains intact.
Clinical Evaluation
History Taking and Index of Suspicion
Mnemonic
Hook:MEDIAL Pain
Specific mechanism questions help predict injury pattern and associated pathology. "Did your foot twist outward while ankle bent inward?" suggests PER mechanism with high syndesmotic injury risk. "Was there direct impact to outside of ankle?" suggests PAB pattern. Previous ankle injuries and pre-existing instability relevant for chronic presentations.
Physical Examination Sequence
Inspection: Observe swelling pattern (isolated medial vs circumferential suggesting syndesmotic injury), ecchymosis distribution (extensive hindfoot ecchymosis indicates grade 2-3 injury), and weight-bearing status. Compare hindfoot alignment to contralateral (valgus suggests chronic deltoid insufficiency or acute deformity).
Palpation Sequence:
- Medial malleolus tip and anterior border (fracture assessment)
- Deltoid course from anterior colliculus inferiorly (ligament disruption creates palpable gap)
- Sustentaculum tali and spring ligament (associated spring ligament injury)
- PTT course posterior to medial malleolus (concurrent PTT pathology)
- Syndesmosis anteriorly (squeeze test, palpation 2-3cm above ankle)
Stress Testing:
- External rotation stress test: Patient seated, knee flexed 90 degrees. Stabilize tibia, apply external rotation force to foot. Compare degree of rotation and pain reproduction to contralateral. Positive if increased rotation and medial pain (indicates deltoid injury, possibly syndesmotic)
- Eversion stress test: Apply eversion force to hindfoot with ankle neutral. Assess medial joint opening. Positive if visible or palpable medial clear space widening
- Cotton test: Lateral translation of talus within mortise. Grasp heel, apply lateral force. Positive if excessive lateral shift compared to contralateral (indicates deltoid AND syndesmotic injury)
- Squeeze test: Compress tibia and fibula at mid-calf. Positive if pain at syndesmosis level (associated syndesmotic injury)
Clinical Pearl
Positive external rotation stress test with medial ankle pain indicates deltoid injury BUT does not differentiate isolated deltoid from combined deltoid-syndesmotic injury. Must assess syndesmosis specifically with squeeze test, external rotation radiograph, and/or MRI. Failure to identify syndesmotic component leads to inadequate treatment and poor outcomes.
Advanced Clinical Tests
Single heel raise test: Assesses PTT function and deltoid competency. Patient stands on affected leg, rises onto toes. Normal response shows hindfoot inversion and heel rise. Inability to perform or lack of hindfoot inversion suggests PTT dysfunction or severe deltoid insufficiency (chronic cases).
Kleiger test: External rotation stress with ankle dorsiflexed and tibia stabilized. Pain localization determines pathology - medial malleolus (deltoid), anterolateral ankle (syndesmosis), or both (combined injury).
Range of motion assessment: Measure dorsiflexion and plantarflexion, compare to contralateral. Reduced dorsiflexion may indicate syndesmotic injury or anterior impingement. Increased eversion suggests deltoid insufficiency.
Imaging Evaluation
Radiographic Assessment
Standard Radiographic Views
AP view: Assess medial clear space (normal less than 4mm, should equal superior clear space). Tibiofibular clear space (normal less than 6mm). Tibiofibular overlap (normal greater than 6mm on AP, greater than 1mm on mortise) Lateral view: Tibiofibular overlap (normal greater than 10mm). Assess for posterior malleolus fracture Mortise view: True AP of ankle joint. Best view for medial clear space assessment and syndesmotic measurements Weight-bearing requirement: Essential for accurate medial clear space measurement. Non-weight-bearing may miss subtle instability Comparison views: Contralateral ankle useful for borderline measurements
Stress Radiography
External rotation stress: Manual or mechanical external rotation of foot with ankle neutral. Assess for medial clear space widening (greater than 2mm difference from contralateral indicates deltoid injury) Gravity stress: Affected leg hangs off table with knee flexed, weight of leg creates stress. Less reproducible than mechanical devices Indications: Suspected deltoid injury with normal standard radiographs, equivocal clinical findings Limitations: Painful, requires patient cooperation, some centers lack mechanical devices Interpretation: Medial clear space widening greater than 4mm absolute or greater than 2mm compared to contralateral is pathologic
Advanced Imaging - MRI
Gold standard: Soft tissue characterization, injury grading, associated pathology identification Protocol: T1, T2, STIR sequences in all three planes. Coronal images best for deltoid assessment Grading on MRI: Grade 1 (intact with edema), Grade 2 (partial thickness tear), Grade 3 (complete disruption with gap) Associated injuries: Syndesmotic ligaments (AITFL, PITFL, IOL), spring ligament, PTT, osteochondral lesions, bone bruising patterns Chronic findings: Ligament thickening, scarring, fatty infiltration, attenuation Indications: Grade 2-3 clinical injury, syndesmotic injury suspected, chronic symptoms, pre-operative planning
Medial clear space greater than 4mm on weight-bearing radiographs indicates deltoid insufficiency UNTIL PROVEN OTHERWISE. This finding mandates assessment for syndesmotic injury (examine tibiofibular clear space, overlap measurements) and consideration of advanced imaging. Isolated deltoid injury rare - look for fractures and syndesmotic disruption.
Bone Bruising Patterns
MRI bone marrow edema patterns predict injury mechanism and associated soft tissue injuries. Kissing bone bruises on medial talus and medial malleolus indicate compression from valgus impact, supporting deltoid injury diagnosis. Anterolateral tibial bruising suggests syndesmotic component. Posterior malleolar bruising indicates posterior translation force and potential posterior malleolus fracture.
MRI and Arthroscopic Correlation
Conservative Management
Treatment Protocol by Grade
Mild Deltoid Sprain Management
Grade 1 injuries represent ligament strain without macroscopic fiber disruption, managed successfully with brief protection and early mobilization.
Acute Phase (0-7 days):
- PRICE protocol: Protection, Rest, Ice, Compression, Elevation
- CAM boot or ankle brace for comfort, weight-bearing as tolerated
- NSAIDs for pain management (ibuprofen 400-600mg TID or naproxen 500mg BID) if no contraindications
- Compression stocking or wrap to control edema
- Cryotherapy 20 minutes every 2-3 hours while awake
Recovery Phase (1-3 weeks):
- Progressive weight-bearing to normal gait pattern
- Active ROM exercises: Ankle alphabet, towel stretches, resistance band exercises
- Begin gentle strengthening: Tibialis posterior activation, toe raises
- Wean from boot/brace as symptoms improve
- Return to normal shoe wear by week 2-3
Return to Activity (3-4 weeks):
- Progressive loading: Walking to jogging progression
- Sport-specific drills without cutting or pivoting
- Proprioceptive training: Single leg balance, balance board
- External ankle support (brace or tape) for high-risk activities
- Full return to sports typically 4-6 weeks
Success rate: 90% complete resolution with conservative management. Chronic symptoms uncommon unless unrecognized associated injury present.
Surgical Management
Acute Surgical Repair Indications
Surgery for acute deltoid injuries is typically performed as part of treatment for associated fractures or syndesmotic injuries rather than isolated ligament repair.
Mnemonic
Hook:FLAIR
Surgical timing depends on injury pattern. Acute fractures with deltoid rupture require surgery within 7-10 days of injury before soft tissue swelling precludes safe approach. Syndesmotic injuries with deltoid rupture treated within first week for optimal reduction. Isolated deltoid ruptures (rare) can undergo delayed repair within first 4 weeks if conservative management failing.
Repair Techniques and Technical Considerations
Approach and Exposure: Curvilinear incision centered over medial malleolus, 6-8cm length. Identify and protect saphenous vein and nerve anteriorly. Create full-thickness flaps exposing medial malleolus and deltoid. Assess level of ligament disruption (tibial avulsion, midsubstance tear, or tarsal insertion avulsion).
Suture Anchor Repair (preferred modern technique):
- Place suture anchors at anatomic origin on medial malleolus based on component injured
- Anterior colliculus for superficial deltoid components
- Intercollicular groove for deep deltoid components
- Use 3.0-3.5mm anchors with high-strength suture (2-0 FiberWire or equivalent)
- Pass sutures through ligament tissue, repair with ankle in neutral dorsiflexion and 5 degrees hindfoot inversion
- Mattress or modified Mason-Allen configuration for optimal strength
- Repair deep layer first (critical for stability), then superficial layer
Bone Tunnel Repair (alternative technique):
- Drill 2.5-3.0mm tunnels through medial malleolus at anatomic origins
- Pass heavy nonabsorbable suture through ligament tissue
- Thread sutures through bone tunnels, tie over bony bridge on medial malleolus
- More time-consuming than anchors but comparable outcomes
Augmentation Options:
- Internal brace (suture tape) can augment repair in high-demand athletes
- Placed from medial malleolus to sustentaculum/medial talus in anatomic deltoid orientation
- Acts as temporary "internal splint" during healing
- Limited evidence but biomechanically sound concept
Concurrent Procedures: Address associated injuries in same setting. Syndesmotic fixation performed first, then assess medial clear space before deltoid repair. Spring ligament repair if identified intraoperatively. Medial malleolus ORIF if fracture pattern present.
Chronic Reconstruction
Chronic deltoid insufficiency with poor tissue quality or failed previous treatment requires reconstruction rather than repair. See medial-ankle-instability topic for detailed reconstruction techniques using autograft or allograft to recreate anatomic ligament complex.
Outcomes and Prognosis
Deltoid Repair vs No Repair in Acute Ankle Fracture (Meta-analysis)
Management of Deltoid Injury in Acute Ankle Fracture (Systematic Review, 3 RCTs)
Role of the Deltoid Ligament in Syndesmotic Instability (Cadaveric)
MRI-Guided Selective Surgery After Positive Stress Test (Weber B)
Gravity Stress Radiographs for Deep Deltoid Integrity in SER Fractures
Deltoid Rupture in Ankle Fracture: Diagnosis and Management (Review)
Prognostic Factors
Favorable prognostic indicators: Isolated grade 1-2 injury, no associated syndesmotic injury, age less than 40 years, normal BMI, sedentary occupation, good rehabilitation compliance, superficial component injury only.
Unfavorable prognostic indicators: Grade 3 complete rupture, deep component injury, associated syndesmotic disruption, age greater than 50, BMI greater than 30, manual labor or competitive athletics, poor rehabilitation access/compliance, delayed diagnosis (greater than 4 weeks).
Return to activity timelines: Grade 1 injuries return to full activity 4-6 weeks. Grade 2 injuries 10-14 weeks. Grade 3 injuries treated conservatively 16-20 weeks. Grade 3 injuries requiring surgery 4-6 months. High-level athletics may require 6-9 months regardless of treatment for complete ruptures.
Complications and Sequelae
Acute Complications
Compartment syndrome: Rare but catastrophic. High-energy deltoid injuries with associated fractures have 2-5% incidence. Presents with pain out of proportion, pain with passive toe extension, tense swelling, paresthesias. Requires immediate fasciotomy of all four compartments. Prevention through careful monitoring and low threshold for compartment pressure measurement.
Vascular injury: Posterior tibial artery injury extremely rare with isolated deltoid injury but possible with high-energy trauma. Assess distal pulses, capillary refill, and Doppler signals. Urgent vascular surgery consultation if compromised perfusion.
Nerve injury: Tibial nerve or plantar branch injury presents with plantar foot numbness, toe flexion weakness. Usually from direct trauma rather than iatrogenic. Document neurovascular status pre-operatively for medicolegal protection.
Chronic Sequelae
Chronic medial ankle pain: Affects 20-30% of inadequately treated injuries. Differential includes deltoid scarring/fibrosis, spring ligament insufficiency, medial ankle impingement, PTT tendinopathy, subtalar arthritis. Requires thorough re-evaluation with MRI and targeted injections for diagnosis.
Medial ankle instability: Develops in 10-15% of grade 3 injuries treated conservatively. Presents with recurrent giving way, difficulty with uneven ground, activity limitation. Objective instability demonstrated on stress radiographs or examination. Treatment requires reconstruction (see medial-ankle-instability topic).
Post-traumatic arthritis: Long-term consequence affecting 15-25% at 10-year follow-up, higher with associated fractures (30-40%). Results from initial cartilage damage, chronic instability causing abnormal joint mechanics, or malreduction of associated fractures. Prevention requires anatomic fracture reduction, addressing instability, and optimizing initial treatment.
Valgus hindfoot deformity: Progressive deformity from untreated chronic deltoid insufficiency combined with spring ligament attenuation. Leads to stage 4 PTTD-type presentation. Prevention requires early identification and reconstruction of chronic instability before fixed deformity develops.
Missed syndesmotic injury is most common and consequential complication of deltoid injury management. Approximately 40-60% of deltoid injuries have associated syndesmotic disruption. Failure to identify and treat syndesmotic component leads to chronic pain, instability, and accelerated arthritis. Mandatory syndesmotic assessment with every deltoid injury using clinical examination, radiographic measurements, and low threshold for MRI.
Differential Diagnosis of Acute Medial Ankle Pain
Medial ankle pain after a twisting injury is not always a deltoid tear. The exam-critical skill is separating these by mechanism, point of maximal tenderness, and the single best discriminating test.
Differential Diagnosis: Medial-Sided Ankle Pain
| feature | mechanism | keyFinding | discriminator |
|---|---|---|---|
| Deltoid ligament injury | Pronation/eversion-external rotation, valgus | Tenderness over deltoid below medial malleolus; pain on ER/eversion stress | Weight-bearing MCS greater than 4mm; deltoid signal change on MRI |
| Medial malleolus fracture | Same rotational forces (bone fails instead of ligament) | Bony point tenderness on the malleolus, possible deformity | Fracture line on radiograph (often the bony equivalent of a deltoid tear) |
| Syndesmotic (high ankle) injury | External rotation with dorsiflexion | Tenderness anterolaterally over AITFL, above the joint line | Positive squeeze and ER tests; widened tibiofibular clear space, often coexists with deltoid tear |
| Posterior tibial tendon (PTT) pathology | Chronic/overuse, acute on chronic; not a single sprain | Tenderness/swelling posterior to medial malleolus, too-many-toes sign, single-heel-raise failure | Tendon (not ligament) on US/MRI; progressive flatfoot rather than acute trauma |
| Spring (calcaneonavicular) ligament injury | Valgus/abduction, often with deltoid or PTT injury | Tenderness over the talonavicular/sustentacular region | Spring ligament disruption on MRI; talar head uncoverage |
| Medial malleolar stress fracture | Repetitive loading in runners | Insidious load-related pain, focal malleolar tenderness | Vertical stress line on radiograph/MRI; no acute traumatic event |
Controversies and Areas of Uncertainty
The deltoid is one of the most genuinely contested soft-tissue topics in foot and ankle surgery. A consultant-level answer acknowledges the equipoise rather than overstating certainty.
To repair or not to repair?
Meta-analysis and systematic review (Guo 2021; James & Dodd 2022) show repair improves radiographic medial clear space and reduces malreduction, but functional outcomes are equivalent and high-quality RCT evidence is lacking. The pragmatic global default remains: restore the fibula/syndesmosis anatomically and explore/repair the deltoid only if the mortise will not reduce or the MCS stays wide.
Does a torn deltoid mean an unstable syndesmosis?
No. Cadaveric work (Massri-Pugin 2018) shows isolated deltoid disruption — even with AITFL — does not destabilise the syndesmosis in the coronal plane; instability requires additional interosseous-ligament injury. A deltoid tear is a marker of energy, not proof of syndesmotic instability.
Is medial clear space a reliable surrogate?
MCS over 4mm is the classic threshold, but Koval (2007) showed a positive stress test overestimates instability — 90% of stress-positive Weber B fractures had only partial deep-deltoid tears and healed nonoperatively. Static MCS does not reliably equal complete rupture; deep-deltoid integrity matters more.
Best imaging to confirm a complete tear?
MRI is the soft-tissue gold standard but is not universally available. Gravity stress radiographs (MCS at least 6mm) reached 100% sensitivity and NPV against MRI (van Leeuwen 2018), making them a validated, low-cost alternative where MRI access is limited.
Viva Revision - Overview
Core Concepts
Deltoid ligament injuries involve damage to the primary medial stabilizer of the ankle joint.
Key Points:
- Represent 3-5% of all ankle sprains
- Deltoid is 2-3 times stronger than lateral ligaments (ATFL)
- Isolated injuries are rare - suspect associated pathology
- Most common mechanism: pronation-external rotation
Injury Spectrum
| Grade | Description | Stability |
|---|---|---|
| Grade 1 | Strain/stretch, intact fibers | Stable |
| Grade 2 | Partial thickness tear | Mild instability |
| Grade 3 | Complete rupture | Unstable |
Anatomy
Deltoid Ligament Components
Superficial Layer:
- Tibionavicular ligament
- Tibiocalcaneal ligament (superficial)
- Tibiospring ligament
- Posterior superficial tibiotalar
- Function: Resists valgus and eversion
Deep Layer:
- Anterior tibiotalar ligament
- Posterior tibiotalar ligament (strongest)
- Tibiocalcaneal ligament (deep)
- Function: Resists external rotation, lateral translation
Layer Comparison
| Feature | Superficial | Deep |
|---|---|---|
| Thickness | 1-2 mm | 3-5 mm |
| Primary Function | Valgus/eversion restraint | Rotation/translation |
| Strongest Component | Tibiocalcaneal | Posterior tibiotalar |
Viva Revision - Grading
Grading System
Three-Grade Classification:
Deltoid Injury Grades
| Grade | Pathology | MRI Finding | Prognosis |
|---|---|---|---|
| Grade 1 | Strain, intact fibers | Edema, no discontinuity | 90% recovery 4-6 weeks |
| Grade 2 | Partial tear | Partial thickness tear | 70-80% recovery 8-12 weeks |
| Grade 3 | Complete rupture | Full discontinuity, gap | 60-70% conservative success |
Clinical Assessment
Examination Findings
Inspection:
- Medial ankle swelling
- Ecchymosis extending to hindfoot (Grade 2-3)
- Hindfoot alignment (valgus suggests chronic)
Palpation:
- Medial malleolus and anterior border
- Deltoid course (palpable gap indicates complete tear)
- Syndesmosis (anterolateral ankle)
Key Clinical Tests
| Test | Technique | Positive Finding |
|---|---|---|
| External rotation stress | Rotate foot externally | Increased rotation + medial pain |
| Eversion stress | Evert hindfoot | Medial joint opening |
| Squeeze test | Compress mid-calf | Syndesmotic pain |
Investigations
Imaging Approach
Radiographs (Essential):
- Weight-bearing AP, lateral, mortise views
- Medial clear space: Normal less than 4 mm
- Tibiofibular measurements for syndesmosis
MRI (Gold Standard):
- Defines injury grade
- Assesses associated pathology
- Guides surgical planning
Key Radiographic Measurements
| Measurement | Normal | Pathological |
|---|---|---|
| Medial clear space | Less than 4 mm | Greater than 4 mm |
| Tibiofibular clear space | Less than 6 mm | Greater than 6 mm |
| Tibiofibular overlap | Greater than 6 mm (AP) | Less than 6 mm |
Decision Flowchart
Surgical Technique
Repair Principles
Approach:
- Curvilinear incision over medial malleolus (6-8 cm)
- Protect saphenous vein and nerve anteriorly
- Full-thickness flaps to expose deltoid
Suture Anchor Technique:
- 3.0-3.5 mm anchors at anatomic origin
- Anterior colliculus: Superficial components
- Intercollicular groove: Deep components
- High-strength suture (2-0 FiberWire)
Repair Techniques
| Technique | Method | Indication |
|---|---|---|
| Suture anchors | Anchors at malleolus | Preferred, modern |
| Bone tunnels | Suture through tunnels | Alternative |
| Internal brace | Suture tape augmentation | High-demand athletes |
Viva Revision - Potential Problems
Potential Problems
Acute:
- Missed syndesmotic injury (most common)
- Nerve injury (saphenous, tibial)
- Wound complications
Chronic:
- Persistent medial pain (20-30%)
- Medial instability (10-15%)
- Post-traumatic arthritis (15-25%)
Complication Overview
| Complication | Incidence | Prevention |
|---|---|---|
| Missed syndesmosis | 40-60% of deltoid injuries | Complete assessment, MRI |
| Chronic pain | 20-30% | Adequate treatment, PT |
| Instability | 10-15% | Identify, treat appropriately |
Postoperative Care
Rehabilitation Protocol
Phase 1 (0-2 weeks):
- Non-weight-bearing in splint/cast
- Elevation, ice for swelling
- Wound care
Phase 2 (2-6 weeks):
- Progressive weight-bearing in CAM boot
- Active ROM exercises
- Avoid forced eversion
Progression Timeline
| Phase | Weight-Bearing | Activity |
|---|---|---|
| 0-2 weeks | Non-weight-bearing | Splint, wound care |
| 2-6 weeks | Progressive in boot | ROM exercises |
| 6-12 weeks | Full weight-bearing | Strengthening, proprioception |
Outcomes
Results by Grade
Conservative Outcomes:
- Grade 1: 90% excellent recovery
- Grade 2: 70-80% good-excellent
- Grade 3: 60-70% conservative success
Surgical Outcomes:
- SER-4 with deltoid repair: 80-85% good-excellent
- Chronic reconstruction: 70-75%
Outcome Summary
| Injury Type | Treatment | Success Rate |
|---|---|---|
| Grade 1 | Conservative | 90% excellent |
| Grade 2 | Conservative | 70-80% good-excellent |
| Grade 3 isolated | Conservative | 60-70% success |
| With fracture | ORIF ± repair | 80-85% success |
Evidence Base
Key Studies
Repair vs no repair, meta-analysis (Guo 2021, PLoS One):
- 8 comparative studies, 388 patients (Weber B/C)
- Repair improved post-op and final medial clear space, AOFAS score and complication rate
- No difference in VAS pain
Systematic review with 3 RCTs (James & Dodd 2022, Can J Surg):
- Functional outcomes equivalent between repair and no repair
- Radiographic MCS and malreduction favoured repair in 5 of 6 studies
Evidence Summary
| Study | Finding | Implication |
|---|---|---|
| Guo 2021 (meta-analysis) | Repair improves MCS/AOFAS, not pain | Selective repair, not routine |
| James & Dodd 2022 (3 RCTs) | Function equal, radiographs favour repair | Equipoise; RCT needed |
| Massri-Pugin 2018 (cadaveric) | Deltoid alone does not destabilise syndesmosis | Assess syndesmosis separately |
| Koval 2007 | 90% stress-positive Weber B heal nonop | MCS overestimates instability |
Clinical Decision Scenarios
Use these scenarios to practise clinical reasoning and management decisions
Acute Deltoid Injury with Equivocal Syndesmotic Injury
"A 26-year-old recreational footballer presents to emergency department 2 hours after twisting injury. Mechanism was landing from jump with foot pronated and externally rotated. Examination shows medial ankle swelling, tenderness over deltoid and anterolateral ankle joint line. External rotation stress test is painful medially and anteriorly. Weight-bearing radiographs show medial clear space of 4.5mm. Tibiofibular clear space is 5.5mm (borderline). MRI not immediately available. How do you proceed?"
Chronic Deltoid Injury with Persistent Pain
"A 42-year-old presents 18 months following ankle sprain initially treated conservatively with 4 weeks CAM boot. She has persistent medial ankle pain with walking and inability to return to running. Examination shows medial ankle tenderness, mild valgus hindfoot alignment, positive but not severe external rotation stress test. Weight-bearing radiographs show medial clear space of 4.8mm. MRI demonstrates chronic deltoid thickening with partial thickness tears of superficial components, intact deep components, and grade 2 spring ligament injury. Failed 6 months physical therapy. What is your management approach?"
Bimalleolar-Equivalent Fracture: Repair the Deltoid?
"A 38-year-old labourer sustains a Weber B fibular fracture with no medial malleolus fracture. Mortise radiograph shows a medial clear space of 6mm. The examiner asks: this is a bimalleolar-equivalent injury. After you fix the fibula, the medial clear space is still 4.5mm. Would you repair the deltoid, and what does the evidence say?"
Exam Day Cheat Sheet
MCQ Practice Points
Clinical Pearl
Q: What are the components of the deltoid ligament and their primary functions?
A: The deltoid ligament has superficial and deep components. Superficial (4 bands): tibionavicular, tibiospring, tibiocalcaneal, posterior tibiotalar - resists eversion/abduction. Deep (2 bands): anterior tibiotalar, posterior tibiotalar (strongest) - primary restraint to external rotation and lateral talar shift. The deep deltoid is the key stabilizer; isolated superficial injury rarely causes instability.
Clinical Pearl
Q: When is deltoid ligament repair indicated in ankle fracture surgery?
A: Deltoid repair is rarely indicated in most ankle fractures. Indications: Medial clear space widening persists (greater than 4mm or greater than superior clear space) after lateral malleolus fixation; Deltoid interposition blocking reduction (interposed tissue visible on stress views); Grossly unstable medial ankle despite lateral fixation. Most cases: Anatomic fibular reduction restores medial stability without direct deltoid repair.
Clinical Pearl
Q: How do you assess deltoid ligament integrity intraoperatively?
A: Intraoperative assessment: (1) Medial clear space measurement on mortise fluoroscopy after fibular fixation - should be less than 4mm and equal to superior clear space; (2) External rotation stress test - widening indicates deep deltoid incompetence; (3) Direct visualization through medial incision if concern for interposed tissue. If medial clear space normalizes with fibular fixation, deltoid is functionally competent even if torn.
Clinical Pearl
Q: What is the clinical significance of isolated deltoid ligament injury without fracture?
A: Isolated deltoid injury is rare and usually occurs with: High ankle sprain (syndesmotic injury pattern); Ankle dislocation without fracture. Treatment: Most heal with non-operative management (immobilization 4-6 weeks). Surgery considered for: Chronic medial instability with valgus tilting; Associated syndesmotic instability requiring fixation; Deltoid avulsion with bone fragment amenable to fixation. Chronic deltoid insufficiency can lead to progressive valgus deformity.
Clinical Pearl
Q: How does deltoid ligament status affect the treatment of Weber B ankle fractures?
A: Weber B fractures are classified as stable (deltoid intact) or unstable (deltoid incompetent). Assessment: Gravity stress radiographs or external rotation stress views - medial clear space widening greater than 4mm indicates deltoid rupture. Stable Weber B (intact deltoid): Non-operative treatment in walking boot. Unstable Weber B (torn deltoid): Requires ORIF of fibula to restore ankle stability. The deltoid determines fracture stability, not just fracture pattern.
Guidelines, Registries & Global Practice
Global Epidemiology and Guideline Positions
Epidemiology: Isolated deltoid injury is rare (roughly 3-5% of ankle sprains). The far more common scenario is deltoid rupture as the medial component of a rotational ankle fracture: a deltoid tear (rather than a medial malleolus fracture) is found in a substantial proportion of supination-external-rotation (SER) and pronation-external-rotation (PER) fractures, creating the bimalleolar-equivalent pattern.
Convergent guidance: No single society publishes a dedicated standalone deltoid-injury guideline; recommendations are embedded in ankle-fracture and ankle-instability guidance. The cross-society consensus is consistent worldwide.
Side-by-Side Guideline / Consensus Positions
| Body | Region | Position on deltoid injury |
|---|---|---|
| AO Foundation | Global | Anatomic fibular (and syndesmotic) reduction is primary; explore/repair deltoid mainly if reduction is blocked or MCS stays wide |
| AAOS-published reviews | US | Bimalleolar-equivalent concept; limited evidence repair improves outcomes over ORIF alone |
| BOA / BOAST (ankle fracture) | UK | Stability-based management; weight-bearing/stress assessment to define unstable Weber B before surgery |
| EFORT / ESSKA (instability) | Europe | Chronic medial instability assessed and reconstructed within a global ankle-instability framework |
Clinical summary
Immediate Answer Opener
- •Deltoid ligament injuries range from grade 1 sprains to complete ruptures, representing 3-5% of ankle sprains
- •Deltoid is 2-3 times stronger than lateral ligaments, making isolated injury rare
- •Most occur with pronation-external rotation mechanisms causing combined deltoid-syndesmotic injuries (SER-4 pattern)
- •Grading: Grade 1 (strain), Grade 2 (partial tear), Grade 3 (complete rupture)
- •Medial clear space greater than 4mm on weight-bearing radiographs indicates pathology
- •Treatment predominantly conservative; surgery for associated fractures/syndesmosis or chronic instability
Anatomy Quick Reference
- •Superficial deltoid: Tibionavicular, tibiocalcaneal, tibiospring ligaments from anterior colliculus
- •Superficial component restrains valgus and eversion
- •Deep deltoid: Anterior and posterior tibiotalar, tibiocalcaneal from intercollicular groove
- •Deep component critical for rotational stability and prevents lateral talar translation
- •Posterior deep tibiotalar is strongest component
- •Deltoid 2-3x stronger than ATFL (800-1200N vs 300-400N tensile strength)
- •Provides 40-50% of ankle stability with intact osseous anatomy
Grading and Injury Mechanisms
- •Grade 1: Intact fibers with edema, mild tenderness, minimal swelling, conservative 2-3 weeks, 90% recovery
- •Grade 2: Partial tear, moderate-severe tenderness and swelling, mild instability, CAM boot 4-6 weeks, 70-80% recovery
- •Grade 3: Complete rupture, extensive ecchymosis, gross instability, often associated injuries
- •Pronation-external rotation: SER-4 with syndesmosis injury (most common mechanism)
- •Pronation-abduction: Associated medial malleolus fracture
- •Direct valgus: Rare isolated deltoid injury
Clinical Examination Essentials
- •External rotation stress test: Knee flexed 90°, externally rotate foot, positive if increased rotation and medial pain
- •Squeeze test: Compress mid-calf, positive if ankle syndesmotic pain
- •Cotton test: Lateral translation of talus, positive if excessive (combined deltoid-syndesmosis)
- •Palpation: Medial malleolus, deltoid course, spring ligament, PTT
- •Always compare stress testing to contralateral ankle for asymmetry
Imaging Interpretation
- •Medial clear space: Normal less than 4mm, pathologic if greater than 4mm or asymmetric to superior clear space
- •Tibiofibular clear space: Normal less than 6mm
- •Tibiofibular overlap: Normal greater than 6mm on AP view
- •MRI grading: Grade 1 intact with edema, Grade 2 partial tear, Grade 3 complete discontinuity
- •MRI must assess syndesmosis (AITFL, PITFL, IOL), spring ligament, PTT, bone bruising
- •Weight-bearing views essential for detecting dynamic instability
Conservative Management Protocol
- •Grade 1: PRICE, CAM boot or brace WBAT, ROM exercises week 1-3, return to activity 4-6 weeks
- •Grade 2: CAM boot NWB progressing to partial weeks 2-3, immobilization 4-6 weeks, structured PT, return to sport 10-14 weeks
- •Grade 3 isolated: Controversial management, NWB cast 2-3 weeks, progressive WB 4-6 weeks, extended rehab 3-6 months
- •Grade 3 conservative success rate: 60-70%
- •Serial radiographs required to monitor for instability development
Surgical Indications and Techniques
- •Indications: Associated fracture requiring ORIF, syndesmotic injury with persistent MCS greater than 4mm, chronic instability failed 6 months conservative, irreducible ankle
- •Approach: Curvilinear medial incision protecting saphenous nerve
- •Suture anchors at anatomic origins: Anterior colliculus for superficial, intercollicular groove for deep
- •Position: Ankle neutral dorsiflexion, 5° hindfoot inversion during repair
- •Consider internal brace augmentation in athletes
- •Address spring ligament if injured
Complications and Outcomes
- •Conservative outcomes: Grade 1 (90% excellent), Grade 2 (70-80% good-excellent), Grade 3 (60-70% success)
- •Surgical repair in SER-4 fractures: 80-85% good-excellent outcomes
- •Missed syndesmotic injury: Most common and consequential complication
- •Chronic medial pain: 20-30%; Persistent instability: 10-15%
- •Post-traumatic arthritis: 15-25% at 10 years (higher with fractures)
- •Prognostic factors: Grade, associated injuries, age, BMI, occupation, rehab compliance, deep vs superficial injury