Courtesy: NIcholas Strasser MD
Vanderbilt Unviersity, Nashville, Tennessee, US
Overview and Background
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Anterior tibial tendon ruptures are rare and not well documented.
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Treatment strategies can be tricky due to the limited literature.
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The speaker has experience with external ankle bracing, which is used in rehabilitation.
Anatomy Review
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The anterior tibial tendon originates from the lateral tibia and runs under the extensor retinaculum.
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It inserts into the medial cuneiform and base of the first metatarsal.
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Innervated by the deep fibular (peroneal) nerve.
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Blood supply includes the anterior tibial artery (proximal) and medial tarsal artery (distal).
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The rupture often occurs in a “watershed” area with less vascular supply.
Function of the Tendon
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Main function is during about 1/3 of the gait cycle.
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In swing phase: helps dorsiflex the foot for toe clearance.
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In stance phase: eccentrically lowers the foot to the ground during heel strike.
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Provides dorsiflexion and inversion.
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Dysfunction may mimic foot drop and lead to tripping or foot slapping.
Pathophysiology and Biomechanics
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Ruptures often occur in tendons with pre-existing tendinopathy.
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Tendon behaves like a spring during gait, storing and releasing energy.
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Muscle fibers don’t change length as much—tendon stretch accounts for motion.
Epidemiology and Presentation
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Much less common than Achilles tendon ruptures.
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Typical patient: active male in 60s–70s, sometimes linked to sports like pickleball.
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Common patient remarks:
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“My foot slaps when I walk.”
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“I trip over my foot.”
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“It’s weak, not painful.”
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“Feels unstable.”
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“I catch my toe when barefoot.”
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Clinical Diagnosis
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Often misdiagnosed as an ankle sprain.
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Important to test ankle dorsiflexion in all “ankle sprain” patients.
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Must check contralateral side for comparison.
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EHL (extensor hallucis longus) may compensate, masking the rupture.
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Gait may show compensatory big toe lift (steppage gait).
Imaging
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MRI is useful—look for distal rupture signs (e.g., “Slytherin sign” or snake-head shape).
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May show associated arthritis or osteophytes irritating the tendon.
Treatment Options
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Non-operative treatment:
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Best for elderly or non-surgical candidates.
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Use of drop foot braces can be surprisingly effective.
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No need to operate on all patients.
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Concern exists about delaying surgery: may lead to muscle atrophy or worsen function.
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Surgical repair:
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Preferred for acute traumatic ruptures.
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Timing and patient selection are key.
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Tendon transfers may be needed in some cases.
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Key Points Summary:
Early Repair (<6 weeks):
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Not always ideal — tendon may be too diseased to heal well.
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Even early, tendon reapproximation can be difficult.
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Standard approach: Anteromedial incision; repair with a Krackow stitch technique.
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If the tendon quality is good, early repair is reasonable.
Techniques for Primary Repair:
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Insertional ruptures can use:
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Suture anchors
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Teno-deses screws
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Endobuttons (looped through the medial cuneiform)
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Goal: regain tendon length — often challenging.
Outcomes & Expectations:
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Only small case series available; no large comparative studies.
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Patients generally do well but rarely regain full strength.
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Residual weakness common — especially in toe extension (EHL still firing).
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Important to counsel patients pre-op: “never quite normal”.
Case Example (Traumatic Laceration):
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Female in her 50s with ATT laceration and retraction.
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Successful acute repair after separate incision for proximal stump.
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Also repaired EHL, EDL.
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Result: functional recovery, but minor imbalance/clawing of toes — typical due to altered length-tension relationship.
If You Can’t Reapproximate Tendon:
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Z-lengthening or free sliding tendon graft using the patient’s own tendon.
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Maintains native anatomy and avoids donor site morbidity.
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Downside: altered tendon biomechanics.
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Gait analysis: good function but not symmetrical — about 50% dorsiflexion compared to the unaffected side.
Chronic Cases: Tendon Transfer Options:
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Most use EHL or EDL transfers.
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EHL transfer:
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In-phase transfer.
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Weak (ATT provides ~80% of dorsiflexion strength).
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Risks: big toe droop.
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May require IP joint fusion to stabilize toe.
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Fixation methods: interference screw, drill hole + loop back.
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Set repair in 10° dorsiflexion.
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Often combined with gastrocnemius recession to reduce posterior tension.
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EDL transfer:
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Weaves EDL into ATT.
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Distal slips tenodesed to EDB.
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Rarely used; mostly case reports.
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Allograft/Autograft Reconstruction:
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Often used when:
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Large gaps or chronic ruptures.
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Extensor tendons not available.
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Needs viable ATT muscle for function.
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Consider MRI of proximal leg to evaluate muscle quality.
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Similar approach to rotator cuff tear evaluation.
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May also achieve tenodesis effect (passive support) even with minimal muscle contraction.
Surgical Technique Overview:
1. Graft Options:
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Allografts are usually preferred due to availability and avoidance of donor site morbidity.
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Hamstring autografts may be used in revisions or when allografts aren’t viable.
2. Graft Fixation Strategy:
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Use of Pulvertaft weave and distal bio-tenodesis for strong fixation.
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If using a longer graft (allograft/autograft), a drill hole in the medial cuneiform can help anchor it.
3. Graft Material:
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Preference for Arthrex FlexBand Twist (5mm x 30mm).
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Benefits: strong suture-holding capacity, spring-like behavior, durable under tension.
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4. Incision and Tissue Management:
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Two-incision approach:
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Distal incision to identify and tag the ATT stump.
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Proximal incision above the extensor retinaculum, preserving overlying soft tissue to reduce wound complications.
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Avoid disruption of the extensor retinaculum, which improves healing and lowers morbidity.
5. Surgical Steps:
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Secure graft distally into medial cuneiform.
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Attach native ATT to graft at distal end.
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Pass graft under retinaculum to proximal ATT stump.
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Max dorsiflex the ankle and tension graft proximally before fixation.
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Reinforce with tendon-to-tendon suture repair, potentially with a Z-lengthening if tension is too high.
Post-Op Rehab Protocol:
0–4 Weeks:
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Splint or cast in maximum dorsiflexion.
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Emphasis on no plantar flexion or stretch—staff instructed not to let foot hang.
4–8 Weeks:
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Transition to a CAM boot.
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Begin passive dorsiflexion, active plantarflexion, progressive weight-bearing.
8+ Weeks:
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Transition to brace or similar:
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Can be locked in dorsiflexion.
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Avoids limb length discrepancy.
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Continue physical therapy to regain strength and function.
Clinical Outcomes:
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Early results show good dorsiflexion strength return.
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Incisions heal well; tendon glides appropriately.
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Avoids drawbacks of autografts (donor site issues), while achieving strong functional restoration.
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