Lateral Ankle Ligament Injuries

History: inversion injury with immediate pain, swelling, and difficulty weight-bearing; a pop may be reported. External rotation or dorsiflexion mechanism suggests a syndesmotic injury. Pain location is anterolateral (ATFL) or at the lateral malleolar tip and below (CFL); medial pain raises suspicion of deltoid injury or medial malleolus fracture; pain above the joint line points to the syndesmosis. Previous sprains are the strongest risk factor - ask about prior rehabilitation completed and current stability. Recurrent giving way suggests developing chronic ankle instability.

Examine systematically:

• •Inspect: swelling (initially anterolateral), bruising that may track distally over 24 to 48 hours
• •Palpate following Ottawa Rules: both malleoli (posterior edge and tip of the distal 6 cm), 5th metatarsal base, navicular, ATFL, CFL, peroneal tendons, syndesmosis above the joint line, and the proximal fibula
• •Stress testing: anterior drawer (the most useful test - increased translation with a soft end-point = ATFL injury); talar tilt (increased inversion tilt = CFL injury). Acute pain and guarding can reduce reliability - reassess at 4 to 5 days post-injury
• •Syndesmosis assessment: squeeze test (pain at the syndesmosis when tibia and fibula are compressed at mid-calf) and external rotation stress test
• •Peroneal tendons: active eversion against resistance; check for subluxation behind the lateral malleolus

The diagnostic cluster of ATFL tenderness plus lateral bruising plus a positive anterior drawer at 4 to 5 day re-examination has been reported with approximately 95 percent positive predictive value for lateral ligament rupture. Red flags include gross deformity, medial tenderness, positive syndesmotic signs, inability to weight-bear despite a normal X-ray, persistent symptoms beyond 6 to 8 weeks (consider osteochondral lesion), and any neurovascular compromise.

The Ottawa Ankle Rules guide imaging decisions; most lateral ankle sprains do not require imaging:

• •Ankle X-ray (AP, lateral, mortise) if there is pain in the malleolar zone AND bone tenderness along the posterior edge or tip of the distal 6 cm of either malleolus, OR inability to weight-bear immediately and in the clinic (four steps)
• •Foot X-ray if there is pain in the midfoot zone AND bone tenderness at the navicular or base of the 5th metatarsal, OR inability to weight-bear

Sensitivity is approximately 98 to 100 percent for clinically significant fractures, reducing unnecessary X-rays by 30 to 40 percent. The rules cannot be reliably applied in intoxication, distracting painful injuries, diminished lower limb sensation, or gross swelling preventing bony palpation. Request a full-length tibia/fibula X-ray if the proximal fibula is tender.

Ultrasound is useful for ligament integrity, peroneal pathology, and effusion but is not routinely required.

MRI is the investigation of choice for suspected osteochondral lesion (persistent symptoms beyond 6 to 8 weeks), syndesmotic injury characterisation, peroneal pathology, and chronic ankle instability.

CT characterises subtle fractures (talar dome, lateral or anterior process).

The vast majority are managed non-operatively, with structured rehabilitation as the cornerstone.

Acute care follows the PEACE & LOVE framework. PEACE (first 48 to 72 hours): Protect (avoid pain-provoking activities, short-term crutches if needed), Elevate, Avoid anti-inflammatories early (a framework concern about suppressing initial healing - simple analgesia such as paracetamol or topical NSAIDs is still routine UK practice), Compress, Educate. LOVE thereafter: Load (early controlled weight-bearing), Optimism, Vascularisation (cardiovascular activity within limits), Exercise (structured rehabilitation).

Functional bracing (semi-rigid stirrup or lace-up brace) is preferred over rigid immobilisation for most Grade I and II sprains, allowing early controlled movement. Short-term immobilisation in a walking boot or below-knee cast may be appropriate for severe Grade III injuries; keep this as short as possible (typically 1 to 2 weeks maximum).

VTE risk assessment is required whenever a patient is placed in a walking boot or below-knee cast, as calf muscle pump function is reduced. Pharmacological prophylaxis may be needed where risk factors are present.

Analgesia: paracetamol or topical NSAIDs first-line per NICE CKS; oral NSAIDs as a short second-line course.

Most isolated Grade III injuries can be managed non-operatively with outcomes equivalent to early surgical repair.

Chronic ankle instability is managed with structured proprioceptive and peroneal strengthening first; bracing during sport reduces re-sprain risk. The Brostrom procedure (anatomical ATFL +/- CFL repair with capsular imbrication) is the standard surgical stabilisation when rehabilitation fails. Refer if symptoms persist beyond 6 to 8 weeks, recurrent sprains despite adequate rehabilitation, suspected osteochondral lesion, syndesmotic instability, or peroneal pathology.

Structured rehabilitation is the single most important intervention. Inadequate rehabilitation is the strongest modifiable predictor of chronic ankle instability.

• •Phase 1 (acute, 0 to 2 weeks): protection, compression, elevation, functional bracing, progressive weight-bearing as tolerated, gentle active range of motion within pain limits, isometric eversion, cryotherapy for swelling
• •Phase 2 (progressive strengthening and proprioception, 2 to 6 weeks): restore full range of motion with particular attention to dorsiflexion; peroneal strengthening (resisted eversion with a band, including eccentric work) is the most important specific exercise; progressive calf strengthening from double-leg to single-leg heel raises; balance training (single-leg stance, eyes open then closed, stable surface to wobble board or foam) is the other critical component
• •Phase 3 (functional, 6 to 12 weeks): jogging, change of direction, cutting, pivoting, agility drills, and plyometrics (hopping, jumping, landing - double-leg to single-leg). Continue peroneal strengthening and proprioception as ongoing maintenance. Brace or tape during sport

Return-to-sport is criteria-based: full dorsiflexion range, adequate peroneal and calf strength, good single-leg balance, pain-free sport-specific activity, and psychological readiness. The 5-PAASS framework structures the assessment across Pain, Ankle impairment, Athlete perception, Sensorimotor control, and Sport performance.

Approximate timelines (rough guides only): Grade I 1 to 3 weeks; Grade II 3 to 6 weeks; Grade III 6 to 12+ weeks. Prevention: previous sprain is the strongest risk factor; proprioceptive training programmes and external ankle support during sport substantially reduce recurrence.

• •Ottawa Ankle Rules (Stiell et al., 1992) - sensitivity approximately 98-100 percent for clinically significant fractures; reduces unnecessary X-rays by 30-40 percent.
• •NICE CKS: Sprains and Strains - paracetamol or topical NSAID first-line; functional bracing preferred over rigid immobilisation for most lateral ankle sprains.
• •PEACE & LOVE consensus (Dubois & Esculier, BJSM 2020) - modern soft-tissue injury framework emphasising protection, education, and progressive loading over rest and ice.
• •Vuurberg et al. (BJSM 2018) - international consensus that supervised exercise and proprioceptive training reduce recurrence after acute lateral ankle sprain.
• •5-PAASS framework (Tassignon et al., 2019) - structured return-to-sport assessment across Pain, Ankle impairment, Athlete perception, Sensorimotor control, and Sport performance.

• •ATFL is the weakest lateral ligament, fails first, and is most vulnerable in plantarflexion; CFL crosses both the ankle AND subtalar joints; PTFL is strongest and rarely tears.
• •Ottawa Ankle Rules have approximately 98-100 percent sensitivity for clinically significant fractures - they rule OUT fracture, NOT ligament severity. Cannot be applied in intoxication, distracting injury, diminished sensation, or when swelling prevents bony palpation.
• •Always palpate the proximal fibula - tenderness mandates a full-length tib/fib X-ray for Maisonneuve fracture.
• •Functional bracing is preferred over rigid casting for Grade I and II sprains; even most Grade III injuries can be managed non-operatively.
• •VTE risk assessment is required when immobilising in a walking boot or cast per UK guidelines.
• •Inadequate rehabilitation is the strongest modifiable predictor of chronic ankle instability; the Brostrom procedure is the standard surgical stabilisation.