High Ankle Sprain (Syndesmosis Injury)

Populations and Risk Factors

Athletes in sports involving rotational forces on a planted foot — football, hockey, soccer, basketball, skiing, rugby — account for the majority of cases
Contact and collision sports carry the highest risk due to external rotation forces applied to the ankle (e.g., another player falling across the lower leg with the foot planted)
Approximately 10–15% of all ankle sprains involve the syndesmosis, but this rises to 20–25% in sports populations
Male athletes have a slightly higher incidence, likely reflecting greater participation in high-impact collision sports
Hyperdorsiflexion mechanism (forced dorsiflexion beyond normal range) — common in skiing (boot-top mechanism) and landing from a jump with excessive forward momentum
Prior ankle sprain history increases risk due to residual ligamentous laxity and altered proprioception
Anatomical variants with a shallow tibial plafond or wider talar dome may predispose to syndesmotic stress

Causes and Pathophysiology

The Syndesmosis Complex

The distal tibiofibular syndesmosis is a four-component ligamentous structure that holds the tibia and fibula together at their distal ends:

Anterior inferior tibiofibular ligament (AITFL): The most commonly injured component; runs obliquely from the anterior tibial tubercle to the anterior fibula; it is the first structure to fail under external rotation stress
Posterior inferior tibiofibular ligament (PITFL): Stronger than the AITFL; runs from the posterior tibial tubercle to the posterior fibula; injured in more severe sprains
Interosseous membrane: A broad fibrous sheet connecting the tibia and fibula along their shafts; the distal portion (the interosseous ligament) is the thickest and strongest part; disruption indicates a severe injury that may involve proximal fibular involvement (Maisonneuve fracture pattern)
Transverse ligament: A deep posterior component that forms the posterior wall of the ankle mortise; contributes to posterior tibiotalar stability

Mechanism of Injury

The syndesmosis is injured when the talus is forced to widen the ankle mortise — pushing the fibula away from the tibia:

External rotation: The most common mechanism — the foot is planted and an external rotational force is applied (by body momentum, another player, or a twisting fall). The talus rotates externally within the mortise, forcing the fibula laterally and tearing the AITFL first, then the interosseous membrane, then the PITFL in sequence
Hyperdorsiflexion: The wider anterior portion of the talar dome is forced deeper into the mortise during extreme dorsiflexion, spreading the tibia and fibula apart. This mechanism is common in skiing and in landing from a height
Eversion: Forced eversion (foot turning outward) places direct lateral stress on the syndesmosis, though this mechanism more commonly injures the deltoid ligament on the medial side

Why Syndesmosis Injuries Heal Slowly

The syndesmotic ligaments have a poorer blood supply compared to the lateral ankle ligaments (ATFL, CFL), and the forces across the syndesmosis during weight-bearing are high:

Every step transmits compressive and rotational force through the syndesmosis — the injured ligaments are continuously loaded during normal walking, preventing the unloading that ligaments need to heal efficiently
The interosseous membrane, when torn, heals with scar tissue that is less elastic and less structurally organized than the original tissue — this creates chronic stiffness and a tendency toward residual widening of the mortise
If the mortise remains even slightly widened (diastasis), the talus no longer fits congruently within it. This incongruency accelerates cartilage degeneration and leads to post-traumatic ankle arthritis — this is why accurate diagnosis and appropriate immobilization are critical

Grading

Grade I: Isolated AITFL sprain without diastasis; stable mortise; pain with provocation tests but no mechanical instability
Grade II: AITFL tear with partial interosseous membrane disruption; mild diastasis may be present on stress radiographs; mortise widening under load
Grade III: Complete disruption of the AITFL, PITFL, and interosseous membrane; frank diastasis with mortise instability; may require surgical fixation with a syndesmosis screw or tightrope device

Signs and Symptoms

Pain location: Pain is localized above the ankle joint line — specifically over the anterolateral distal leg between the tibia and fibula, in contrast to lateral ankle sprains where pain is at or below the malleolus
Mechanism history: Patient typically reports a twisting or rotational injury with the foot planted; may describe an external rotation force or a hyperdorsiflexion event; often reports "this feels different from a regular ankle sprain"
Weight-bearing difficulty: Difficulty or inability to bear weight is disproportionate to the visible swelling — patients with high ankle sprains often describe significant functional limitation with relatively modest external swelling, which is the opposite pattern of lateral ankle sprains
Swelling: Less dramatic external swelling than a lateral ankle sprain; swelling tends to be diffuse along the anterolateral distal leg (between tibia and fibula) rather than localized at the malleolus
Stiffness: Dorsiflexion is the most limited and painful movement — the wider anterior talar dome is forced into the compromised mortise during dorsiflexion, reproducing the injury mechanism
Proximal leg pain: In severe injuries, tenderness may extend proximally along the interosseous membrane — if tenderness reaches the proximal fibula, suspect a Maisonneuve fracture (proximal fibula fracture with complete syndesmosis disruption) and refer for imaging immediately

Assessment Profile

Subjective Presentation

Chief complaint: "I twisted my ankle but the pain is higher up than usual" or "it doesn't feel like a normal ankle sprain"; may report significant difficulty weight-bearing despite what appears to be modest swelling; often occurred during a sport or a misstep with a rotational component
Pain quality: Deep ache between the tibia and fibula above the ankle joint; sharp pain with pushing off during walking or with any twisting motion of the foot; stiffness rather than instability is the dominant complaint
Onset: Acute traumatic onset — external rotation of the foot on a planted leg, or forced dorsiflexion; patient can usually describe the mechanism clearly; may have heard or felt a "pop" or "crack" above the ankle
Aggravating factors: Weight-bearing (especially push-off phase of gait), dorsiflexion, external rotation of the foot, walking on uneven surfaces, ascending stairs, any twisting motion at the ankle
Easing factors: Rest, elevation, compression wrap, avoiding weight-bearing, keeping the foot in neutral (avoiding dorsiflexion and rotation)
Red flags: Tenderness extending to the proximal fibula → suspect Maisonneuve fracture; refer for imaging immediately; inability to bear weight for 4 steps → apply Ottawa ankle rules; refer for radiographic assessment; rapid gross swelling with visible deformity → suspect fracture-dislocation; emergency referral

Observation

Local inspection: Diffuse swelling along the anterolateral distal leg between the tibia and fibula; less localized than the anterior talofibular swelling seen in lateral ankle sprains; ecchymosis (bruising) may appear 24–48 hours post-injury in the anterolateral ankle and may track distally to the foot; in severe injuries, visible widening of the ankle mortise may be apparent on comparison with the uninjured side
Posture: Antalgic stance with weight shifted to the unaffected side; ankle held in slight plantarflexion (avoiding dorsiflexion, which loads the syndesmosis); may be unable to stand on the affected leg
Gait: Significantly antalgic — shortened stance phase on the affected side with avoidance of push-off (the push-off phase requires dorsiflexion, which loads the syndesmosis); lateral trunk lean toward the affected side to reduce ground reaction force; may require crutches or assistive device

Palpation

Tone: Peroneal muscles (peroneus longus and brevis) may be hypertonic or in spasm as a protective response; gastrocnemius-soleus complex guarding to limit dorsiflexion; tibialis anterior guarding; overall muscle tone in the lower leg is increased bilaterally in acute presentation due to pain-avoidance patterns
Tenderness: AITFL — tenderness over the anterolateral distal tibiofibular articulation, approximately 2–3 cm above the ankle joint line (the hallmark finding); interosseous membrane tenderness along the distal leg between the tibia and fibula; PITFL — posterior distal tibiofibular tenderness (more difficult to palpate); proximal fibula — if tender, suspect Maisonneuve fracture and refer. The key clinical distinction: tenderness is above the ankle joint line, not at or below the malleolus
Temperature: Warmth over the anterolateral distal leg in the acute phase reflecting active inflammation; compare bilaterally
Tissue quality: Edematous tissue with a boggy quality in the acute phase; reduced fascial mobility along the interosseous membrane; in subacute and chronic phases, fibrotic thickening may be palpable along the AITFL and the distal interosseous membrane

Motion Assessment

AROM: Dorsiflexion is the most limited and painful movement — the wider anterior talar dome spreads the compromised mortise. Plantarflexion is relatively preserved. Inversion and eversion may reproduce pain but are typically less limited than in lateral ankle sprains. External rotation of the foot is consistently provocative.
PROM / end-feel: Dorsiflexion PROM reproduces pain with a protective/guarded end-feel; plantarflexion end-feel is typically normal (firm); the end-feel on external rotation stress is the key diagnostic finding — increased laxity (soft/empty end-feel) compared to the uninjured side indicates syndesmotic instability
Resisted testing: Resisted dorsiflexion may reproduce pain (tibialis anterior contraction loads the interosseous membrane); resisted eversion may also be painful; resisted plantarflexion is usually less affected; note that muscle strength is typically maintained (no myotomal deficit) — weakness is pain-inhibited rather than neurological

Special Test Cluster

Test	Positive Finding	Purpose
Squeeze Test (Proximal Fibular Compression) (CMTO)	Compression of the tibia and fibula together at the mid-calf level reproduces pain at the distal syndesmosis (above the ankle joint line) — pain is referred distally, not at the compression site	Confirm syndesmosis injury — the squeeze transmits force through the interosseous membrane to the injured distal syndesmosis
Kleiger Test (External Rotation Stress Test) (CMTO)	Pain at the anterolateral syndesmosis and/or lateral widening of the ankle mortise when the foot is externally rotated with the ankle in neutral or slight dorsiflexion	Confirm syndesmosis injury — reproduces the external rotation mechanism that injured the AITFL; the most specific provocation test for syndesmosis
Dorsiflexion Maneuver (Dorsiflexion with Compression) (supplementary)	Pain at the syndesmosis during weight-bearing dorsiflexion (e.g., lunging forward over the planted foot) that decreases when the tibia and fibula are manually compressed together during the same maneuver	Confirm syndesmosis — the manual compression stabilizes the mortise and reduces pain by approximating the tibia and fibula; pain reduction with compression is the key positive finding
Cotton Test (Lateral Talar Shift) (supplementary)	Excessive lateral translation of the talus within the mortise compared to the uninjured side when a lateral force is applied to the talus	Confirm mortise instability (diastasis) — indicates the syndesmosis is no longer maintaining normal mortise width; positive Cotton test suggests Grade II or III injury
Fibular Translation Test (supplementary)	Excessive anterior-posterior translation of the fibula relative to the tibia at the distal syndesmosis compared to the uninjured side	Confirm syndesmotic laxity — direct assessment of the fibular-tibial relationship at the syndesmosis
Anterior Drawer (Ankle) (CMTO — rule out)	Excessive anterior translation of the talus with a soft end-feel	Rule out ATFL injury (lateral ankle sprain) — a positive anterior drawer with a negative squeeze and Kleiger suggests lateral rather than syndesmotic injury; both may coexist in combined injuries

Cluster interpretation: The Squeeze Test and Kleiger Test are the two most clinically reliable tests for syndesmosis injury. A positive Squeeze Test is highly suggestive because the pain is referred distally to the injury site rather than produced locally. A positive Kleiger with a positive Squeeze Test provides strong diagnostic confidence. The Dorsiflexion Maneuver adds specificity: if pain decreases with manual tibial-fibular compression during the maneuver, the syndesmosis is the pain source. A positive Cotton Test indicates mortise instability and suggests a more severe grade.

Differential Diagnoses

Condition	Key Distinguishing Feature
Lateral ankle sprain (ATFL/CFL)	Tenderness at or below the lateral malleolus (not above the joint line); positive anterior drawer and talar tilt; negative Squeeze Test and Kleiger; more localized swelling at the malleolus
Distal fibula fracture	Point tenderness over the distal fibula with crepitus or deformity; apply Ottawa ankle rules; refer for imaging if criteria met
Maisonneuve fracture	Proximal fibula tenderness with distal syndesmosis disruption — the fracture is proximal but the ligament injury is distal; easily missed if the proximal fibula is not palpated; refer for imaging immediately
Deltoid ligament sprain (medial ankle)	Tenderness over the medial malleolus and deltoid ligament; pain with eversion stress; may coexist with syndesmosis injury as part of the same rotational mechanism
Osteochondral lesion of the talus	Persistent deep ankle pain after apparent sprain recovery; clicking or locking; pain with weight-bearing compression; refer for imaging if symptoms persist beyond expected healing time

CMTO Exam Relevance

Classified under MSK conditions of the ankle and foot (A5 orthopedic); exam questions may test the distinction between lateral ankle sprain (ATFL/CFL below the malleolus) and syndesmosis injury (above the joint line)
The Squeeze Test is a commonly tested special test — the key concept is that compression at the mid-calf produces pain distally at the syndesmosis (referred pain through the interosseous membrane)
Kleiger (External Rotation Stress Test) reproduces the mechanism of injury — understand that external rotation forces the talus laterally, widening the mortise
The significantly longer healing time (2–3 times that of a lateral ankle sprain) is clinically significant and may appear in exam scenarios involving return-to-activity counseling
Ottawa ankle rules may be tested in the context of a high ankle sprain — inability to bear weight for 4 steps mandates radiographic referral
Maisonneuve fracture is a classic "must not miss" scenario — always palpate the proximal fibula when syndesmosis injury is suspected

Massage Therapy Considerations

Primary therapeutic target: The surrounding musculature that becomes hypertonic and restricted in response to the syndesmotic injury — peroneals, gastrocnemius-soleus, tibialis anterior, and tibialis posterior. The ligamentous injury itself heals through immobilization and time, not through direct MT intervention. MT supports recovery by managing the compensatory muscular dysfunction that develops during the healing and rehabilitation phases.
Sequencing logic: Address the proximal compensators first (calf musculature, peroneals) before approaching the distal injury zone → release muscular guarding that restricts dorsiflexion range → gentle circulatory work around (not directly over) the syndesmosis to support healing → progressive proprioceptive and mobility work as healing allows. The syndesmosis itself should not receive direct deep pressure until pain-free palpation is possible and ligament healing is confirmed.
Safety / contraindications: Do not apply direct pressure over the injured syndesmosis in the acute phase — the ligaments are healing and direct force may disrupt the process. Avoid forced dorsiflexion stretching — dorsiflexion loads the compromised mortise. In the acute phase (first 72 hours to 2 weeks), RICE/PRICE principles take priority over MT intervention. If proximal fibula tenderness is present, do not treat — refer for Maisonneuve fracture investigation. Do not perform aggressive soft tissue work if a fracture has not been ruled out.
Heat/cold guidance: Cold application over the anterolateral ankle is the primary hydrotherapy in the acute and subacute phases to manage inflammation and pain; moist heat to the calf musculature (not directly over the syndesmosis) may be used in the subacute phase to reduce muscular guarding before treatment; contrast hydrotherapy in the chronic phase to manage residual stiffness and promote circulation

Treatment Plan Foundation

Clinical Goals

Reduce compensatory muscular hypertonicity in the lower leg (peroneals, gastrocnemius-soleus, tibialis anterior)
Restore pain-free dorsiflexion range progressively as syndesmotic healing allows
Manage edema and support circulatory return in the subacute and chronic phases
Prepare the ankle musculature for rehabilitation and return to activity

Position

Supine with the ankle elevated on a bolster — primary position for anterior and lateral lower leg access; elevation supports venous return and edema management
Prone — for calf musculature (gastrocnemius-soleus) access; foot hanging off the end of the table in slight plantarflexion to avoid syndesmotic stress
Side-lying — alternative for peroneal access if prone or supine is uncomfortable

Session Sequence

General effleurage to the entire lower leg — assess tissue state, promote circulatory return, and identify areas of maximal guarding; work proximal to distal to facilitate lymphatic drainage [Subacute phase onward]
Myofascial release to gastrocnemius and soleus — reduce calf guarding that restricts dorsiflexion; the calf muscles protect the ankle by limiting dorsiflexion range, but chronic guarding perpetuates stiffness beyond the healing need
Sustained compression and cross-fiber work to peroneus longus and brevis — address lateral compartment hypertonia and trigger points; the peroneals are primary evertors and become overworked as dynamic stabilizers after syndesmotic injury
Myofascial release to tibialis anterior and the anterior compartment — reduce anterior guarding; the tibialis anterior becomes hypertonic from altered gait mechanics (avoidance of push-off, increased dorsiflexor demand during swing phase)
Gentle cross-fiber friction at the AITFL and distal syndesmosis — [Subacute to chronic phase only — not before 3–4 weeks post-injury and only when direct palpation is pain-free]; promotes organized collagen alignment during ligament remodeling; light pressure within tolerance
Effleurage and gentle lymphatic drainage techniques around the ankle — manage residual edema in the subacute and chronic phases; work from distal to proximal to facilitate lymphatic return
Reassess dorsiflexion AROM post-treatment — compare with pre-treatment baseline to document progress

Adjunct Modalities

Hydrotherapy: Cold application over the anterolateral ankle post-treatment in the subacute phase to manage reactive inflammation; moist heat to the calf (not directly over the syndesmosis) pre-treatment in the subacute and chronic phases to improve tissue pliability; contrast hydrotherapy (alternating warm and cool) in the chronic phase to address residual stiffness and promote local circulation
Remedial exercise (on-table): Gentle active dorsiflexion-plantarflexion within pain-free range — promotes synovial fluid circulation and maintains available ROM during healing; towel scrunches and marble pickups (toe flexor activation) to maintain intrinsic foot strength; single-leg balance (eyes open, then closed) on the treatment table to retrain proprioception [Chronic phase, when weight-bearing is pain-free]

Exam Station Notes

Demonstrate knowledge that the syndesmosis is above the ankle joint line — clearly differentiate the injury location from a lateral ankle sprain
Perform the Squeeze Test and explain the referred pain mechanism (compression at mid-calf reproduces pain distally at the syndesmosis)
Verbalize Ottawa ankle rules when applicable — state the criteria for radiographic referral
Show awareness of the Maisonneuve fracture risk by verbalizing the need to palpate the proximal fibula

Verbal Notes

Acute phase communication: "Your injury is to the ligaments that hold the two lower leg bones together above the ankle — this is different from a typical ankle sprain and takes longer to heal. It's important to follow your prescribed immobilization plan"
Treatment phase: "I'll be working on the muscles around your ankle and lower leg to reduce the tightness that's developed while you've been protecting the injury. I'll avoid direct pressure over the injured area until it's ready"
Post-treatment advisory: mild soreness in the calf and lower leg muscles is normal; any increase in swelling, sharp pain at the syndesmosis, or new symptoms should be reported

Self-Care

Ankle alphabet exercise — trace each letter of the alphabet with the big toe to maintain active ROM in all planes within pain-free range; 1–2 times daily [Subacute phase onward]
Calf stretching — gentle gastrocnemius and soleus stretches (wall lean with knee straight then bent) once dorsiflexion is no longer provocative; hold 30 seconds, 2–3 times daily; do not force dorsiflexion into pain
Single-leg balance training — stand on the affected leg for 30 seconds; progress from eyes open to eyes closed; perform on a stable surface initially, then progress to an unstable surface (pillow, balance board); 2–3 times daily; this is the most important self-care exercise for preventing re-injury through improved proprioception
Activity modification — avoid premature return to sport or high-impact activity; the syndesmosis takes 2–3 times longer to heal than a lateral ankle sprain; return to activity should be guided by the treating physician or physiotherapist and should include sport-specific agility testing before full clearance

Key Takeaways

High ankle sprains (syndesmosis injuries) involve the AITFL, PITFL, interosseous membrane, and transverse ligament — the structures that bind the distal tibia and fibula together to maintain the ankle mortise
Pain is localized above the ankle joint line (not at the malleolus), which is the primary clinical distinction from the far more common lateral ankle sprain
The Squeeze Test (mid-calf compression producing distal syndesmotic pain) and the Kleiger Test (external rotation stress) are the two most reliable clinical tests for syndesmosis injury
Syndesmosis injuries heal 2–3 times more slowly than lateral ankle sprains due to poor blood supply and continuous weight-bearing forces across the syndesmosis during normal walking
Always palpate the proximal fibula when syndesmosis injury is suspected — tenderness there indicates a possible Maisonneuve fracture requiring immediate imaging referral
MT's primary role is managing the compensatory muscular dysfunction (peroneal, calf, and tibialis anterior guarding) that develops during healing, not treating the ligament directly in the acute phase
Direct cross-fiber friction at the syndesmosis is appropriate only in the subacute to chronic phase, when direct palpation is pain-free and ligament healing is progressing
The dorsiflexion maneuver with manual tibial-fibular compression is a valuable confirmatory test — if pain decreases when the mortise is manually compressed, the syndesmosis is the pain source