Medically reviewed by Dr. Tom Biernacki, DPM
Board-certified podiatric surgeon | Balance Foot & Ankle, Howell & Bloomfield Township, MI
Last reviewed: May 2026
| Feature | FHB Tear / Sesamoid Complex Injury | Sesamoiditis (Inflammation Only) | Sesamoid Stress Fracture | Plantar Plate Tear (1st MTP) |
|---|---|---|---|---|
| Structure involved | Flexor hallucis brevis muscle/tendon; sesamoid bones embedded within it | Sesamoid bone periosteum; FHB tendon sheath | Sesamoid bone cortex (tibial or fibular sesamoid) | Plantar plate capsule of 1st MTP |
| Pain location | Plantar 1st MTP; directly under sesamoids; worsens with hallux dorsiflexion | Same distribution; typically more diffuse | Focal under sesamoid; progressive with activity | Plantar 1st MTP; capsular region |
| Mechanism | Acute: forced dorsiflexion (turf toe); Chronic: repetitive push-off (running, ballet) | Repetitive loading without acute event | Repetitive loading; progressive | Forced dorsiflexion (turf toe mechanism) |
| MRI hallmark | FHB tendon discontinuity or signal defect adjacent to sesamoid; sesamoid edema | Peritendinous edema; no tendon defect; no fracture line | Fracture line through sesamoid + bone marrow edema | Plantar plate signal defect at 1st MTP; SPRAIN pattern |
| Hallux dorsiflexion | Severely limited; painful; may show instability at 1st MTP | Painful at end range | Painful at end range | Limited; instability may allow excessive dorsiflexion |
| Treatment | Boot NWB 4–8 weeks; PT; surgical repair if complete tear with functional deficit | Offloading pad; stiff-soled shoe; cortisone injection | NWB boot 6–8 weeks; bone stimulator; sesamoidectomy if AVN/nonunion | Buddy taping; stiff shoe; Weil osteotomy + plate repair if Grade III |
| Rehabilitation Phase | Timeline | Goal | Key Exercises / Interventions |
|---|---|---|---|
| Phase 1: Sesamoid Unloading | Weeks 1–6 | Protect FHB/sesamoid complex; reduce inflammation | NWB or toe-off boot; dancer’s pad; avoid barefoot; gentle ankle ROM non-weight-bearing |
| Phase 2: Controlled Loading | Weeks 6–10 | Begin hallux plantarflexion strengthening; restore pain-free ROM | Seated towel scrunches; theraband hallux flexion; marble pickups; stiff-soled shoe transition |
| Phase 3: Push-Off Training | Weeks 10–16 | Restore FHB function for push-off biomechanics | Single-leg calf raises; toe-walking progression; balance board; eccentric FHB loading |
| Phase 4: Return to Sport | Months 4–6 | Full sport-specific loading; prevent recurrence | Sport drills; custom orthotic with sesamoid relief cutout; transition to sport shoe; jumping/cutting drills |
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Medically Reviewed | Dr. Tom Biernacki, DPM | Board-Certified Podiatric Surgeon | Balance Foot & Ankle, Michigan
Understanding Flexor Hallucis Brevis Tears
The flexor hallucis brevis (FHB) is a critical intrinsic muscle of the foot whose two tendinous heads enclose the tibial (medial) and fibular (lateral) sesamoid bones beneath the first metatarsophalangeal (MTP) joint. The FHB originates from the plantar cuboid and lateral cuneiform, courses plantarward to embrace the sesamoids within its tendon, and inserts into the base of the proximal phalanx of the hallux. Its primary function is to flex the hallux at the MTP joint — the essential motion for push-off propulsion during walking and running.
FHB tears are less commonly discussed than plantar plate tears or sesamoid fractures, but they represent a clinically significant injury that can devastate first MTP joint function if unrecognized. The complex anatomy — a bifurcated tendon investing two sesamoid bones and merging with the abductor hallucis and adductor hallucis tendons at the great toe — makes FHB injuries particularly consequential for forefoot biomechanics.
At Balance Foot & Ankle, Dr. Tom Biernacki evaluates all significant great toe MTP injuries with MRI to assess FHB integrity — because clinical examination alone cannot distinguish FHB tear from sesamoid fracture, plantar plate disruption, or turf toe grade without imaging.
Anatomy and Functional Importance
The FHB’s two muscle bellies form a V-shaped plantar structure with the sesamoids embedded at the apex — creating the sesamoid complex that protects the FHB tendon from compressive loading during push-off. During normal gait, the FHB complex bears up to 3× body weight per step.
The plantar plate of the first MTP joint is a dense fibrocartilaginous structure that blends intimately with the FHB tendon insertions and the collateral ligaments — creating the “volar plate” complex that resists hallux dorsiflexion (the position of greatest FHB stress). This intimate anatomy means that FHB injuries almost always co-occur with plantar plate disruption — and the two structures must be assessed simultaneously.
The FHB also provides critical medial-lateral stability at the first MTP joint — dysfunction creates instability that progresses to hallux deformity (hallux valgus or varus drift) if untreated.
Mechanism of Injury
FHB tears occur through two primary mechanisms:
Hyperextension force (Turf Toe Mechanism): Forced dorsiflexion of the hallux at the MTP joint — typically from a fall forward over a planted foot on an artificial or hard surface — places the FHB and plantar plate under extreme tensile stress. Grade III turf toe injuries involve complete plantar plate disruption with FHB avulsion from the sesamoid-metatarsal unit. This is the most common high-grade FHB injury mechanism, classically occurring in football linemen, soccer players, and martial artists.
Direct compression or crush: A heavy object dropped onto the forefoot, or a forceful landing on the ball of the foot, can rupture the FHB directly. This mechanism often co-occurs with sesamoid fracture.
Chronic overload/tendinosis: Repetitive loading in runners and dancers can generate FHB tendinosis — intratendinous degeneration without frank rupture — presenting as insidious plantar forefoot pain that worsens progressively over weeks to months.
Clinical Presentation
FHB tears present with a characteristic symptom cluster localized to the plantar forefoot and great toe:
Pain: Sharp, localized plantar pain at the sesamoid region and first MTP joint, acutely worsened with push-off and hallux dorsiflexion. In complete tears, pain may temporarily diminish as the ruptured tendon no longer transmits force — while functional loss becomes the dominant presentation.
Weakness: Reduced or absent active hallux plantarflexion strength. The examiner resists hallux flexion against the patient’s effort — significant asymmetry (compared to the contralateral foot) indicates FHB disruption. In complete tears, the patient cannot perform a single-leg toe raise on the affected side.
Ecchymosis and swelling: Plantar bruising and swelling at the first MTP joint are common in acute tears — particularly prominent in crush or turf toe injuries. The plantar skin may show characteristic arch-shaped bruising following the course of the FHB insertion.
Deformity: In complete FHB disruption, unopposed extensor hallucis longus (EHL) pull creates progressive hallux extension deformity — the hallux drifts into dorsiflexion at the MTP joint if the FHB counterbalance is lost.
Diagnostic Evaluation
MRI: The gold standard for FHB tear assessment. MRI demonstrates:
- FHB tendon fiber disruption or complete retraction
- Plantar plate integrity (co-injury assessment)
- Sesamoid bone marrow edema (distinguishing sesamoid fracture from pure tendon injury)
- Joint effusion quantification
- Collateral ligament status
Dr. Biernacki obtains MRI for all suspected Grade II–III turf toe injuries and for any plantarflexion weakness following forefoot trauma — because the clinical examination alone cannot reliably detect partial vs. complete FHB disruption.
Ultrasound: Dynamic imaging that visualizes FHB tendon fibers in real time — useful for detecting partial tears and assessing tendon excursion during hallux flexion-extension testing. More accessible than MRI for initial evaluation but less comprehensive for plantar plate and bone assessment.
Weight-bearing radiographs: Assess sesamoid position (proximal migration in complete FHB disruption), sesamoid fracture, and first MTP joint alignment. Tibial sesamoid retraction suggests FHB tendon discontinuity.
Treatment
Conservative Management (Grade I–II Injuries):
Partial FHB tears and turf toe Grade I–II injuries respond to structured conservative management:
- Rigid-soled footwear or carbon fiber plate insole preventing first MTP dorsiflexion for 4–6 weeks
- Custom sesamoid-offloading orthotic with metatarsal pad and sesamoid relief cutout
- Physical therapy — intrinsic hallux strengthening beginning at 6 weeks, progressing to functional movements
- Taping: FHL/FHB-protective taping limiting hallux dorsiflexion during return to activity
Surgical Repair (Grade III Complete Tears):
Complete FHB avulsion with plantar plate disruption — particularly with sesamoid retraction or instability — requires surgical repair for restoration of first MTP function:
- Plantar plate primary repair with anchor fixation to the proximal phalanx base
- FHB tendon re-approximation and sesamoid reposition
- Collateral ligament repair where disrupted
- Return to sport at 4–6 months with position-specific functional rehabilitation
Untreated complete FHB disruption with persistent sesamoid retraction and hallux extension deformity eventually requires late reconstruction — FHL tendon transfer or interphalangeal fusion to restore functional push-off capability.
Dr. Tom's Product Recommendations
Strassburg Sock (Plantar Fasciitis Night Splint Version)
⭐ Highly Rated
Nighttime stretching device that maintains the hallux in neutral dorsiflexion position — useful during FHB tendinosis rehabilitation to gently maintain length in the recovering tendon without the compressive loading of walking. Also maintains plantar fascia and intrinsic muscle flexibility during FHB recovery.
Dr. Tom says: “My podiatrist recommended this at night during my FHB tendinosis recovery. Keeping the toe stretched while sleeping helped reduce morning stiffness dramatically.”
FHB tendinosis patients using nighttime gentle stretching as part of the conservative rehabilitation protocol
Acute complete FHB tear — passive stretching is contraindicated until tendon repair healing is confirmed at 6-8 weeks
Disclosure: We earn a commission at no extra cost to you.
Vivobarefoot Primus Trail Firm Ground Running Shoe
⭐ Highly Rated
Wide-toe-box trail shoe that allows full intrinsic muscle engagement — recommended for late-phase FHB rehabilitation when restoring intrinsic hallux strength and sensorimotor function. The wide forefoot accommodation prevents sesamoid compression while allowing first MTP functional movement during the return-to-activity phase.
Dr. Tom says: “My podiatrist had me transition to these wide-toe-box shoes during the last phase of my toe rehab. My hallux strength came back much faster.”
Late-stage FHB rehabilitation patients rebuilding hallux plantarflexion strength and MTP joint proprioception (typically 3+ months post-injury)
Early recovery phase (0-12 weeks) — wide minimalist shoes with no first MTP protection are contraindicated until tendon healing is confirmed
Disclosure: We earn a commission at no extra cost to you.
Kinesio Tape Classic Roll (2 inches)
⭐ Highly Rated
Kinesiology tape used by Dr. Biernacki’s patients for FHB-protective hallux taping — reduces MTP joint dorsiflexion during return-to-activity, providing proprioceptive feedback and limiting the hyperextension position that stress the FHB insertion. Used as supplementary protection during sports return phase.
Dr. Tom says: “My podiatrist showed me how to tape my big toe for MTP protection during running. The kinesio tape technique significantly reduced my forefoot pain during return to running.”
FHB injury patients using hallux protective taping during the return-to-activity rehabilitation phase (6-16 weeks post-injury)
Skin sensitivity or allergy to medical adhesive, or patients in the acute phase requiring rigid orthotic protection rather than flexible taping
Disclosure: We earn a commission at no extra cost to you.
✅ Pros / Benefits
- MRI evaluation of FHB, plantar plate, and sesamoid integrity for complete injury mapping
- Custom sesamoid-offloading orthotics with first MTP dorsiflexion protection during recovery
- Graded rehabilitation protocol distinguishing Grade I-II conservative management from Grade III surgical repair
- Surgical plantar plate and FHB repair with sesamoid repositioning for complete tears
- Late reconstruction options for chronic FHB disruption with hallux extension deformity
- Sport-specific return-to-activity protocols for athletes with Grade II-III turf toe/FHB injuries
❌ Cons / Risks
- Grade III FHB tears with complete plantar plate disruption require surgical repair and 4–6 months of recovery
- Unrepaired FHB tears can progress to hallux extension deformity requiring more extensive reconstruction
- MRI is essential for definitive diagnosis — clinical exam alone cannot distinguish FHB tear from sesamoid fracture or plantar plate tear
Dr. Tom Biernacki’s Recommendation
FHB tears are frequently missed in the initial evaluation of turf toe injuries — the clinician orders X-rays, doesn’t see a sesamoid fracture, and declares the injury ‘minor’ without obtaining an MRI. But a Grade III turf toe with complete FHB and plantar plate avulsion is not minor — it’s a structural injury that will leave the athlete with chronic first MTP instability, weak push-off, and progressive hallux deformity if it’s not properly repaired. My rule for any athlete with a significant turf toe mechanism and plantar forefoot pain: MRI before deciding on treatment. The MRI takes 30 minutes and tells me everything — FHB integrity, plantar plate status, sesamoid bone, collateral ligament health. That information determines whether I’m managing a 6-week conservative rehab or a surgical repair.
— Dr. Tom Biernacki, DPM | Board-Certified Podiatric Surgeon | Balance Foot & Ankle
Frequently Asked Questions
What is the flexor hallucis brevis?
The flexor hallucis brevis (FHB) is an intrinsic foot muscle with two heads that encase the sesamoid bones beneath the big toe joint. It flexes the great toe at the MTP joint — the primary motion for push-off propulsion. The FHB tendon invests the sesamoids and merges with the plantar plate, creating the critical plantar complex that stabilizes the first MTP joint against the hyperextension forces of walking and running.
How does FHB tear differ from sesamoid fracture?
Both injuries cause plantar forefoot pain at the sesamoid region. Sesamoid fracture involves a break in the sesamoid bone itself (detected on MRI as bone marrow edema with fracture line). FHB tear involves disruption of the tendon fibers that invest the sesamoids — the bone may be intact but the tendon and plantar plate are torn. MRI distinguishes them definitively. Both can co-occur in high-energy mechanisms.
What is turf toe and how does it relate to FHB injury?
Turf toe is a hyperextension sprain of the first MTP joint, graded I–III by severity. Grade I involves minor FHB/plantar plate stretching; Grade II involves partial disruption; Grade III involves complete FHB and plantar plate avulsion from the sesamoid-metatarsal unit. FHB tears are the defining injury of Grade III turf toe. The injury occurs when the toe is forced into extreme dorsiflexion while the forefoot is planted — common in football linemen and soccer players.
Can FHB tears be treated without surgery?
Grade I-II partial FHB tears respond to conservative treatment: rigid-soled footwear and sesamoid-offloading orthotics for 4–8 weeks, followed by intrinsic strengthening rehabilitation. Grade III complete tears with plantar plate avulsion generally require surgical repair for restoration of adequate first MTP function and prevention of progressive hallux deformity.
How long does recovery take from an FHB tear?
Grade I–II injuries return to full activity in 6–12 weeks with proper conservative management. Grade III surgical repairs require 4–6 months for full return to sport — 6 weeks non-weight-bearing, 3 months protected return to activity, then sport-specific functional rehabilitation. Athletes who return prematurely risk re-injury and chronic instability.
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When should I see a podiatrist?
If symptoms persist past 2 weeks, affect your normal activity, or are accompanied by red-flag symptoms (warmth, redness, swelling, inability to bear weight).
What does treatment cost?
Most diagnostic visits and conservative treatments are covered by Medicare and major insurers. Out-of-pocket costs vary by your specific plan.
How quickly can I get an appointment?
Most non-urgent cases see us within 5 business days. Urgent cases (sudden pain, possible fracture) typically same or next business day.
Foot pain typically responds best to early podiatrist evaluation, conservative treatments such as supportive footwear and targeted physical therapy, and—when needed—custom orthotics or in-office procedures. Most patients see meaningful improvement within 4-6 weeks of starting a structured treatment plan. Schedule an evaluation at our Howell or Bloomfield Township office for a clinical assessment.
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Dr. Tom Biernacki, DPM is a board-certified foot & ankle surgeon (ABFAS & ABPM) at Balance Foot & Ankle Specialists in Southeast Michigan. With over a decade of clinical experience, he specializes in heel pain, bunions, diabetic foot care, sports injuries, and minimally invasive surgery. Dr. Biernacki is a member of the APMA and ACFAS, and his patient education content on MichiganFootDoctors.com and YouTube has made him one of the most-followed foot & ankle educators on YouTube.
More questions patients ask
What is a flexor hallucis brevis tear?
See our full guide from Dr. Tom Biernacki DPM at Balance Foot & Ankle, Howell & Bloomfield Township, MI.
What are the symptoms of an FHB tear?
See our full guide from Dr. Tom Biernacki DPM at Balance Foot & Ankle, Howell & Bloomfield Township, MI.
How is flexor hallucis brevis tear treated?
See our full guide from Dr. Tom Biernacki DPM at Balance Foot & Ankle, Howell & Bloomfield Township, MI.
When should I see a podiatrist for big toe plantar pain?
See Dr. Tom Biernacki at Balance Foot & Ankle — same-day appointments. Call (810) 206-1402. Howell & Bloomfield Township, MI.
Does insurance cover FHB tear treatment in Michigan?
Most PPO and Medicare plans cover medically necessary foot care. We accept BCBS and most Michigan insurers. Call (810) 206-1402.
Still have a question about coverage or cost? Book online and we will check your benefits before your visit: Book in Howell · Book in Bloomfield Township. Prefer to talk it through first? Call (810) 206-1402.