Pediatric Toe Deformity | Flexor Tenotomy | Age 4-12 Years | High Success Rate
- Flexor tenotomy: Divide both FDB and FDL through small plantar incision at PIPJ
- Age 4-12 years: Optimal age for simple tenotomy - flexible deformity, high success
- Digital nerves: Run on sides, not midline - incision must be exactly midline
- Both tendons essential: FDB (superficial) and FDL (deeper) must both be divided
- Post-op care: Gauze between toes, heel weight-bearing initially
- “Viva question: Walk me through flexor tenotomy for curly toe
- “Key point: TWO tendons (FDB and FDL) must be divided, not just one
- “Incision: 2-3mm transverse at PIPJ flexion crease, exactly midline
- “Complications: Digital nerve injury, recurrence, overcorrection
Under 4 years: Observe - may resolve spontaneously. 4-12 years: Flexor tenotomy (FDB + FDL) - optimal age, high success. Over 12 years: Tenotomy often insufficient, may need tendon transfer or osteotomy. Age determines procedure choice.
FDB (flexor digitorum brevis) and FDL (flexor digitorum longus) must BOTH be divided. FDB is superficial (splits into 2 slips), FDL is deeper (single tendon). Incomplete release leads to recurrence. Toe should straighten immediately after division.
Digital nerves run on the SIDES, not midline. Incision must be exactly midline at PIPJ flexion crease to avoid nerve injury. 2-3mm transverse incision is sufficient. Protect neurovascular bundles throughout.
Flexible deformity: Passively correctable - tenotomy works well. Rigid deformity: Fixed contracture - tenotomy insufficient, needs bony procedure (fusion, osteotomy). Assess flexibility before surgery.
- Deformity Type
- Flexible, may be asymptomatic
- Treatment
- Observation - may resolve spontaneously
- Key Pearl
- Many resolve without treatment
- Deformity Type
- Flexible, symptomatic
- Treatment
- Flexor tenotomy (FDB + FDL)
- Key Pearl
- Optimal age, 90%+ success rate
- Deformity Type
- May be rigid
- Treatment
- Tendon transfer or osteotomy
- Key Pearl
- Simple tenotomy often insufficient
- Deformity Type
- Rigid, fixed contracture
- Treatment
- Bony procedure (fusion, osteotomy)
- Key Pearl
- Soft tissue release insufficient
Overview and Epidemiology
Curly toes is a common pediatric toe deformity characterized by flexion and rotation of the toe, causing it to curl under adjacent toes. It most commonly affects the 3rd, 4th, or 5th toes and is caused by tightness of the flexor digitorum brevis (FDB) and flexor digitorum longus (FDL) tendons.
Epidemiology:
- Common pediatric condition
- Most commonly affects 3rd, 4th, or 5th toes
- Bilateral in many cases
- Often familial (may run in families)
- More common than other lesser toe deformities in children
- Usually presents in early childhood
Curly toes can cause functional problems (pain, difficulty with shoes, catching on socks) and cosmetic concerns. Simple flexor tenotomy is highly effective for flexible deformities in children aged 4-12 years, with 90%+ success rates. Understanding the age-appropriate treatment and surgical technique is essential for optimal outcomes.
Etiology:
- Tight flexor tendons: FDB and FDL are relatively tight
- Muscle imbalance: Flexors overpower extensors
- Familial tendency: May run in families (genetic component)
- Developmental: Present from early childhood
- Not acquired: Unlike adult lesser toe deformities
- Tight shoes: May worsen but not cause
- Growth: Deformity may become more apparent with growth
- Flexibility: Flexible deformities respond better to tenotomy
- Age: Older children may develop fixed contractures
Natural History:
- Under 4 years: Many resolve spontaneously with growth
- 4-12 years: Usually stable or slowly progressive if untreated
- Over 12 years: May become rigid, less responsive to simple tenotomy
- Functional impact: Variable - some asymptomatic, others have significant problems
Pathophysiology of Curly Toe Deformity
Flexor Tendon Anatomy
The Two Flexor Tendons:
- Origin: Calcaneal tuberosity
- Insertion: Middle phalanges (splits into 2 slips)
- Action: Flexes PIPJ and MTPJ
- Location: Superficial to FDL
- In tenotomy: Must be divided first (superficial)
- Origin: Posterior tibia
- Insertion: Distal phalanges (single tendon)
- Action: Flexes DIPJ, PIPJ, MTPJ
- Location: Deep to FDB
- In tenotomy: Must be divided second (deeper)
Digital Neurovascular Anatomy:
- Location
- Run on lateral and medial sides of toe
- Clinical Significance
- Incision must be midline to avoid injury
- Location
- Run with nerves on sides
- Clinical Significance
- Protected by midline approach
- Location
- Midline, contains tendons
- Clinical Significance
- Safe to incise for tenotomy
Digital nerves run on the lateral and medial sides of each toe, NOT in the midline. The incision for flexor tenotomy must be exactly midline at the PIPJ flexion crease to avoid nerve injury. A 2-3mm transverse incision is sufficient and safe if placed correctly.
Pathophysiology:
- Tight flexors: FDB and FDL are relatively tight compared to extensors
- Flexion deformity: Toe flexes at PIPJ and DIPJ
- Rotation: Toe rotates medially or laterally
- Under-riding: Toe curls under adjacent toe
- Functional problems: Pain, difficulty with shoes, catching
CURLYCurly Toe Features - CURLY
Hook:CURLY toes - Common, Under-riding, Rotation, Longus/brevis tight, Young children benefit most!
Classification Systems
Treatment Classification by Age
- Deformity Type
- Flexible, may resolve
- Treatment
- Observation
- Success Rate
- Subset improve with growth (~25% per literature)
- Deformity Type
- Flexible, symptomatic
- Treatment
- Flexor tenotomy (FDB + FDL)
- Success Rate
- ~95% success (Ross & Menelaus 1984)
- Deformity Type
- May be rigid
- Treatment
- Tendon transfer or osteotomy
- Success Rate
- Variable, depends on flexibility
- Deformity Type
- Rigid, fixed
- Treatment
- Bony procedure (fusion, osteotomy)
- Success Rate
- Good if flexible component addressed
Age is the primary factor in choosing treatment. Under 4 years: observe. 4-12 years: flexor tenotomy (optimal). Over 12 years: may need more complex procedures. Always assess flexibility - rigid deformities need bony procedures regardless of age.
Clinical Assessment
History:
- Age: Critical for treatment planning
- Symptoms: Pain, difficulty with shoes, catching on socks?
- Progression: Getting worse or stable?
- Family history: Other family members with curly toes?
- Shoe wear: Problems with specific shoes?
- Functional limitations: Any impact on activities?
- Pain: From nail weight-bearing or dorsal rubbing
- Corns/calluses: From shoe pressure
- Functional problems: Catching on socks, difficulty with shoes
- Cosmetic concerns: Significant deformity causing distress
- Under-riding: Toe causing pressure on adjacent toes
- Age 4-12 years: Optimal age for tenotomy
Physical Examination:
Systematic Examination
- Toe position: Flexed and rotated, curling under adjacent toe
- Which toes: Usually 3rd, 4th, or 5th toes
- Bilateral: Check both feet
- Skin changes: Corns, calluses, nail problems
- Shoe wear: Any pressure marks or deformities
- Passive correction: Can toe be straightened manually?
- Flexible: Fully correctable = tenotomy appropriate
- Rigid: Fixed contracture = needs bony procedure
- Partially rigid: Some correction = may need additional release
- Tendon tightness: Palpate flexor tendons
- Joint contractures: Assess PIPJ and DIPJ
- Pain: Localize any tender areas
- Gait: Any abnormalities?
- Shoe fit: Problems with specific shoes?
- Activities: Any limitations?
Flexibility assessment is critical. Flexible deformities respond well to tenotomy. Rigid deformities need bony procedures. Always test passive correction before planning surgery. If the toe cannot be passively corrected, simple tenotomy will fail.
Differential Diagnosis of the Deformed Lesser Toe
The single most common examiner trap is to label every malpositioned lesser toe a "curly toe". Each deformity has a distinct plane, mechanism and operation. Curly toe is a flexion-and-rotation deformity driven by tight long flexors; it must be separated from the coronal-plane overlapping toe, the hyperextension-based hammer/claw/mallet toes, and the dorsally subluxed congenital overriding fifth toe.
- Toe(s) / Plane
- 3rd-5th; flexion + rotation (varus)
- Key Mechanism
- Tight FDL ± FDB; toe curls plantar/medial under neighbour
- Distinguishing Feature
- Toe tip points down and under, nail rotated; usually flexible
- Typical Treatment
- Observation or open flexor tenotomy
- Toe(s) / Plane
- 5th; dorsal + adduction
- Key Mechanism
- Tight extensor (EDL) and dorsomedial MTPJ capsule
- Distinguishing Feature
- 5th toe rides OVER 4th dorsally, opposite plane to curly toe
- Typical Treatment
- Butler / extensor release with capsulotomy
- Toe(s) / Plane
- Flexion at PIPJ, extension at MTPJ
- Key Mechanism
- Flexor/extensor imbalance at PIPJ
- Distinguishing Feature
- Acquired in adults; PIPJ buckles, DIPJ neutral
- Typical Treatment
- Flexor tenotomy/transfer or PIPJ fusion
- Toe(s) / Plane
- Extension MTPJ + flexion PIPJ and DIPJ
- Key Mechanism
- Intrinsic minus, often neurological
- Distinguishing Feature
- Multiple toes, look for cavus/neuromuscular cause
- Typical Treatment
- Treat cause; transfers, fusions
- Toe(s) / Plane
- Isolated flexion at DIPJ
- Key Mechanism
- Tight FDL at distal phalanx
- Distinguishing Feature
- Tip callus only; PIPJ normal
- Typical Treatment
- Distal flexor tenotomy
- Toe(s) / Plane
- Coronal-plane varus, may overlap with curly
- Key Mechanism
- Skin/soft-tissue contracture
- Distinguishing Feature
- May tuck under without true flexion-rotation
- Typical Treatment
- Taping in neonate; release if persistent
The classic discriminator: a curly fifth toe curls plantarward and UNDER the fourth toe (flexion-rotation, FDL-driven), whereas a congenital overriding fifth toe rides dorsally OVER the fourth toe (extension-adduction, EDL/capsule-driven). They are opposite-plane deformities needing opposite operations - flexor surgery versus the Butler extensor-release procedure. Do not confuse them.
Most curly toes are idiopathic and often familial, but a lesser-toe flexion deformity can be the first sign of a neuromuscular disorder, and missing this is a classic trap. Be suspicious when the picture is atypical:
- Progressive worsening rather than a stable congenital deformity.
- Multiple toes or a claw-toe pattern (extension at MTPJ with flexion at PIP and DIP) rather than the isolated 3rd-5th flexion-rotation of true curly toe.
- Associated pes cavus, a high arch, or hindfoot varus.
- Asymmetry, sensory changes, weakness, or an abnormal gait.
- A family history of neuropathy or a known neurological condition.
These features should prompt a focused neurological examination and consideration of Charcot-Marie-Tooth disease (hereditary motor-sensory neuropathy), spinal dysraphism / tethered cord, or cerebral palsy. The cavus-clawtoe combination in particular is Charcot-Marie-Tooth until proven otherwise. Treating the toe in isolation without recognising the underlying disease leads to recurrence and misses the real diagnosis.
Investigations
Imaging:
- AP and lateral foot: Usually normal in curly toes
- Purpose: Rule out skeletal abnormalities, assess joint alignment
- Not diagnostic: Clinical diagnosis, X-rays confirm no bony deformity
- Optional: May not be needed for simple cases
- Atypical presentation: Unusual deformity pattern
- Rigid deformity: Assess for joint contractures or bony abnormalities
- Multiple deformities: Rule out underlying conditions
- Pre-operative planning: For complex cases
Curly toes is a clinical diagnosis. The presence of a flexed and rotated toe curling under adjacent toes is diagnostic. Radiographs are usually normal and not required for simple cases. Imaging is reserved for atypical presentations or pre-operative planning in complex cases.
Management Algorithm
Management by Age Group
Treatment Protocol by Age
May resolve spontaneously:
- Observation: Most cases improve with growth
- Reassurance: Explain to parents that many resolve
- Follow-up: Reassess at age 4 if still present
- No intervention: Avoid surgery in very young children
Optimal age for tenotomy:
- Indication: Symptomatic flexible curly toe
- Procedure: Flexor tenotomy (FDB + FDL)
- Success rate: 90%+ with appropriate technique
- Timing: Can be done anytime in this age range
May need more than tenotomy:
- Assess flexibility: If flexible, tenotomy may still work
- If rigid: Needs tendon transfer or osteotomy
- Tendon transfer: FDL to extensor hood (Girdlestone-Taylor)
- Osteotomy: If bony deformity present
Treatment must be age-appropriate. Under 4 years: observe. 4-12 years: tenotomy (optimal). Over 12 years: assess flexibility - may need more complex procedures. Do not perform tenotomy in very young children who may improve spontaneously.
AGECurly Toe Treatment by Age - AGE
Hook:AGE determines treatment - young children may improve, school age is optimal for tenotomy, older children need more complex procedures!
Surgical Technique
Flexor Tenotomy Technique (Age 4-12 Years)
Principle: Divide both FDB and FDL tendons through a small plantar incision to release the flexor pull and allow the toe to straighten.
Flexor Tenotomy Steps
Supine position: Patient on operating table Frog-leg position: Hip flexed and externally rotated for access to plantar foot Tourniquet: Ankle or thigh tourniquet for hemostasis Exposure: Plantar surface of affected toe(s) clearly visible
Location: Plantar surface at PIPJ flexion crease Size: 2-3mm transverse incision Position: Exactly midline (critical to protect digital nerves) Depth: Through skin and subcutaneous tissue to flexor sheath
Open flexor sheath: Identify flexor tendons FDB (superficial): Splits into 2 slips, divide both slips FDL (deeper): Single tendon, divide completely Confirm division: Toe should straighten immediately when both divided Complete release: Ensure no residual tightness
Close incision: Single stitch or Steristrips Gauze between toes: Maintain correction and prevent recurrence Dressing: Non-constrictive, allow for swelling No splint: Usually not needed for simple tenotomy
BOTH FDB and FDL must be divided. FDB is superficial (splits into 2 slips - divide both). FDL is deeper (single tendon). Incomplete division of either tendon leads to recurrence. The toe should straighten immediately when both are divided - this confirms complete release.
Digital nerves run on the lateral and medial sides of each toe, NOT in the midline. The incision must be exactly midline at the PIPJ flexion crease. A 2-3mm transverse incision is sufficient and safe. Deviation from midline risks nerve injury.
Open flexor tenotomy is the classic, reliable operation, but a percutaneous (needle) flexor tenotomy is a recognised, lower-morbidity alternative for the flexible toe and is the standard technique in some settings:
- Percutaneous: under local or general anaesthesia, the flexor tendon(s) are divided through a stab or needle (e.g. a hypodermic needle or a small blade) introduced at the flexion crease, sweeping across the tendon until the toe straightens - no formal incision or suture.
- Advantages: minimal scar (so it cannot cross and tether a flexion crease - the documented cause of failure in open tenotomy), quick, day-case, often under local anaesthetic in a cooperative child.
- Caveats: it is a "blind" division, so completeness is judged by the toe straightening on the table; the same digital-nerve-on-the-sides rule applies and a guarded midline entry is essential.
- Percutaneous distal flexor tenotomy is also the workhorse for the diabetic/neuropathic toe with an apical (tip) ulcer or a mallet toe, where it offloads the tip with negligible morbidity.
The examiner is testing that you know both exist and that the principle - complete release confirmed by on-table correction, with the scar kept away from a flexion crease - matters more than the specific approach.
MIDLINEFlexor Tenotomy Technique - MIDLINE
Hook:MIDLINE incision protects the nerves - Make Incision, Divide both, Longus and brevis, Immediate result, Nerves safe, Ensure complete!
Complications
- Incidence
- 5-10%
- Risk Factors
- Incomplete division of FDB or FDL
- Management
- Revision tenotomy
- Incidence
- Less than 1%
- Risk Factors
- Incision not midline, poor technique
- Management
- Usually resolves, may need exploration
- Incidence
- Rare
- Risk Factors
- Excessive release
- Management
- Usually mild, observation
- Incidence
- Less than 5%
- Risk Factors
- Contamination
- Management
- Antibiotics, local care
- Incidence
- Rare
- Risk Factors
- Nerve injury
- Management
- May need excision if symptomatic
Recurrence is usually from incomplete division. Both FDB and FDL must be completely divided. FDB splits into 2 slips - both must be divided. FDL is a single tendon but must be fully divided. Always confirm the toe straightens immediately after division.
Postoperative Care and Rehabilitation
Postoperative Protocol
- Gauze between toes: Maintain correction, prevent recurrence
- Heel weight-bearing: Initially, to protect repair
- Elevation: Reduce swelling
- Pain management: Usually minimal pain
- Dressing change: Check wound, replace gauze between toes
- Suture removal: 10-14 days if sutures used
- Continue gauze: Between toes for 2-4 weeks
- Gradual weight-bearing: Progress to full weight-bearing
- Remove gauze: After 2-4 weeks when correction maintained
- Normal activities: Resume as comfort allows
- Shoe wear: Normal shoes when comfortable
- Follow-up: Clinical assessment for recurrence
- Monitor: Check for recurrence at follow-up visits
- Functional assessment: Ensure normal toe function
- Cosmetic: Assess final appearance
- Additional procedures: Rarely needed if initial procedure successful
Key Post-operative Points:
- Gauze between toes: Critical to maintain correction and prevent recurrence
- Heel weight-bearing: Initially to protect the repair
- Minimal pain: Usually well-tolerated procedure
- Quick recovery: Most children return to normal activities within 2-4 weeks
Outcomes
- Excellent results in 90%+ with appropriate flexor tenotomy
- Recurrence rate 5-10% (usually from incomplete division)
- Age 4-12 years has best outcomes
- Simple day-case procedure with quick recovery
- Most children return to normal activities within 2-4 weeks
- Cosmetic and functional improvements are usually excellent
- Age: 4-12 years has best outcomes
- Flexibility: Flexible deformities respond better than rigid
- Complete division: Both FDB and FDL must be divided
- Post-operative care: Gauze between toes important to prevent recurrence
Flexor tenotomy for curly toes has a roughly 95% success rate (Ross and Menelaus, 188 toes) when performed correctly. The key is complete division of the offending flexor tendon(s) and an incision that does not cross a flexor crease. This is one of the most successful and lowest-morbidity pediatric foot procedures.
Guidelines, Registries & Global Practice
Global epidemiology
- Congenital curly/varus/underlapping and overlapping toes were found in 2.8% of newborns screened in a prospective study (Smith et al).
- The deformity is frequently bilateral and often familial (autosomal dominant tendency reported in some families), affecting the 3rd, 4th and 5th toes most often.
- Best estimate of true spontaneous improvement is around 25% (world literature, Smith et al); the remainder persist but are commonly asymptomatic.
- There is no implant or arthroplasty registry relevant to curly toe - it is a soft-tissue paediatric procedure - so the evidence base is case-series driven rather than registry driven, unlike adult forefoot reconstruction.
Side-by-side guidance from major bodies
- Conservative
- Observe asymptomatic flexible toes
- Surgical threshold
- Persistent symptomatic deformity
- Procedure of choice
- Open flexor tenotomy
- Conservative
- Reassure; taping of limited value beyond infancy
- Surgical threshold
- Symptoms (pain, footwear, skin breakdown)
- Procedure of choice
- Open flexor tenotomy; transfer/osteotomy if rigid
- Conservative
- Observation; flexor lengthening considered to preserve flexion
- Surgical threshold
- Symptomatic or severe overlapping
- Procedure of choice
- Tenotomy or FDL Z-lengthening (+/- FDB)
- Conservative
- Limited role
- Surgical threshold
- Severe overlapping by age 2-3 years
- Procedure of choice
- FDB slip tenotomy +/- capsular release / skin flap
The points of genuine divergence are timing (earlier in severe overlapping per the Tokioka school versus a symptom-led approach elsewhere) and division versus lengthening of the flexor. All converge on observation for the asymptomatic flexible toe and on a flexor-based soft-tissue operation as the workhorse.
High- versus limited-resource practice variation
- Day-case procedure under general or regional anaesthesia
- Routine paediatric orthopaedic or paediatric surgical follow-up
- Easy access to early review and revision if recurrence occurs
- Low threshold to image atypical or rigid toes before surgery
- Often performed under local anaesthesia in older cooperative children, minimising theatre and anaesthetic burden
- Clinical diagnosis without routine radiographs is entirely appropriate (cost-saving and accurate)
- Neonatal taping is an attractive low-cost first-line option where the deformity is recognised at birth
- Strong emphasis on reserving surgery for genuinely symptomatic toes given limited operative capacity
Regardless of health system, document the flexibility assessment, which flexor tendon(s) were divided, and confirmation that the toe straightened on the table. Consent should cover recurrence (around 5%), digital nerve injury (rare) and the principle that some minor toes are better observed than operated.
Controversies and Areas of Uncertainty
The "facts" most candidates recite about curly toes are softer than they sound. Being able to articulate the genuine areas of debate marks out a strong answer.
There is no consensus age. A symptom- and flexibility-led pathway is widely taught, but Tokioka and colleagues argue that severe overlapping toes should be corrected by 2-3 years because spontaneous correction is unlikely and later surgery risks skeletal deformity. Others defer until school age to avoid operating on toes that may settle. The honest answer is that timing is individualised, not fixed.
Simple division sacrifices active toe flexion (usually clinically irrelevant), whereas Z-lengthening (Jacobs and Vandeputte) aims to preserve flexion power and strength. Whether retaining active flexion of a lesser toe matters functionally is unproven, and lengthening is technically more demanding.
Teaching ranges from FDB slip only (Tokioka) to both FDB and FDL (the common exam answer). Ross and Menelaus emphasised dividing whatever short flexor is the sole cause of deformity. The pragmatic rule: divide enough that the toe straightens fully on the table, then confirm.
Strapping fails to hold correction once stopped in older children (Turner), yet neonatal taping cured or improved 94% of toes (Smith). The window in which non-operative treatment works may be confined to the first weeks of life - a genuine and underappreciated nuance.
The often-quoted "most curly toes resolve" is an overstatement. The best literature figure for true spontaneous improvement is around 25% (Smith et al, citing world literature). Counsel families accordingly: many toes are minor and never need treatment, but do not promise that the deformity will disappear.
MCQ Practice Points
Q: What is the optimal age for flexor tenotomy for curly toes? A: 4-12 years is the optimal age range. Under 4 years, many resolve spontaneously with observation. Over 12 years, simple tenotomy may be insufficient and more complex procedures may be needed. Age 4-12 years has the best outcomes with tenotomy (90%+ success rate).
Q: Which tendons must be divided for curly toe tenotomy? A: Both FDB (flexor digitorum brevis) and FDL (flexor digitorum longus) must be divided. FDB is superficial and splits into 2 slips (both must be divided). FDL is deeper and is a single tendon (must be completely divided). Incomplete division of either leads to recurrence.
Q: Where should the incision be made for flexor tenotomy? A: Exactly midline at the PIPJ flexion crease on the plantar surface. Digital nerves run on the lateral and medial sides of the toe, not midline. A 2-3mm transverse incision in the midline is safe and protects the nerves. Deviation from midline risks nerve injury.
Q: What is the key post-operative measure to prevent recurrence? A: Gauze between toes for 2-4 weeks maintains correction and prevents recurrence. The toe should be kept straight with gauze padding. Heel weight-bearing initially protects the repair. This simple measure significantly reduces recurrence risk.
Q: What is the recurrence rate after flexor tenotomy for curly toes? A: 5-10% recurrence rate, usually from incomplete division of FDB or FDL. If both tendons are completely divided and post-operative care is appropriate (gauze between toes), recurrence is uncommon. Revision tenotomy is usually successful if the initial release was incomplete.
Q: What is the success rate of flexor tenotomy for curly toes? A: 90%+ success rate when performed correctly in children aged 4-12 years. The key factors are: complete division of both FDB and FDL, appropriate age (4-12 years), flexible deformity, and proper post-operative care with gauze between toes.
Exam Viva Scenarios
Practise clinical reasoning and management decisions out loud
“Walk me through flexor tenotomy for a curly toe in a 6-year-old child.”
“A 3-year-old has curly toes affecting both 4th toes. The parents want surgery. What is your approach?”
“A 10-year-old had flexor tenotomy for curly toe 6 months ago, but the deformity has recurred. How do you manage this?”
Age-Based Treatment
- Under 4 years: Observe - a subset improve with growth (~25% per literature)
- 4-12 years: Flexor tenotomy (FDB + FDL) - 90%+ success
- Over 12 years: May need tendon transfer or osteotomy
- Rigid deformity: Needs bony procedure regardless of age
Surgical Technique
- Incision: 2-3mm transverse, exactly midline at PIPJ crease
- Divide FDB: Superficial, splits into 2 slips (divide both)
- Divide FDL: Deeper, single tendon (divide completely)
- Confirm: Toe should straighten immediately when both divided
Key Anatomy
- Digital nerves: Run on lateral and medial sides, NOT midline
- FDB: Superficial, splits into 2 slips
- FDL: Deeper, single tendon
- Midline approach: Safe for both tendons, protects nerves
Post-operative Care
- Gauze between toes: 2-4 weeks to maintain correction
- Heel weight-bearing: Initially, progress to full
- Minimal pain: Usually well-tolerated
- Quick recovery: 2-4 weeks to normal activities
Complications
- Recurrence: 5-10% if incomplete division
- Digital nerve injury: Less than 1% if midline approach
- Overcorrection: Rare
- Wound infection: Less than 5%
Evidence Base
The evidence for curly toes is dominated by retrospective case series; there are no high-level randomised trials of operative technique. The studies below are the most frequently cited and are presented with their verified sample sizes and outcomes. A recurring theme is that open flexor tenotomy reliably corrects flexible deformity, that failure correlates with surgical technique (scar crossing a flexion crease) rather than with age, and that conservative strapping/taping does not produce durable correction beyond the neonatal period.
Open Flexor Tenotomy for Curly and Hammer Toes (Landmark Series)
- 62 children (188 toes) reviewed at mean 9.8 years after open flexor tenotomy
- Operation unsuccessful in only 5% of toes (95% success)
- Identifiable cause of failure was the scar crossing one or more flexor creases - a technical, not age-related, error
- No patient was aware of loss of flexor power; only one toe was stiff (from scar tethering)
Flexor Tenotomy in the Treatment of Curly Toes (Original Description)
- Early case series establishing flexor tenotomy as treatment for symptomatic curly toes
- Demonstrated preserved toe movement after tendon division
- Helped define curly toe as a flexor-driven deformity of the toe joints
Open Tenotomy of Flexor Digitorum Brevis for Curly Toe
- 8 toes in 7 children treated by open tenotomy of the medial slip of FDB (with capsular release for severe cases)
- Median age 2 years 6 months; overlapping corrected in every case at median 2 years 9 months follow-up
- Residual flexion/varus persisted in the most severe toes
- Authors argue severe overlapping toes should be corrected by 2-3 years because spontaneous correction is unlikely and later surgery risks skeletal deformity
Flexor Tendon Lengthening for Hammer and Curly Toes
- Retrospective series of flexor tendon lengthening (rather than simple tenotomy) at mean 31 months follow-up
- Deformity improved in all patients, with less improvement in the 4th and 5th toes
- Active toe flexion and strength recovered in all patients
- Recommended Z-lengthening of FDL for hammer toes plus FDB tenotomy for curly toes
Strapping of Curly Toes - Conservative Treatment Has No Durable Effect
- Retrospective review of 49 children treated by strapping (24 children, 44 toes reviewed)
- Strapping improved 68% of toes while maintained, but correction was lost significantly once strapping stopped
- Sustained improvement was not sufficient to justify strapping for this minor deformity
- Author recommends open flexor tenotomy and reserves treatment for the more severely deformed toe
Neonatal Taping for Congenital Curly/Underlapping and Overlapping Toes
- Prospective study of 84 toes taped within 10 days of birth and reviewed by an independent assessor
- 94% of toes improved or cured with no complications
- Quoted world literature suggests only about 25% spontaneous improvement without treatment
- Toe abnormalities occurred in 2.8% of newborns screened
Spread of Practice - AAOS/POSNA and BSCOS Educational Guidance
- Curly toe is described as a common, usually benign, often familial flexible deformity of the lesser toes
- Observation is recommended for the asymptomatic toe; many improve or stabilise with growth
- Open flexor tenotomy is the standard operation for the persistently symptomatic flexible toe
- Rigid or fixed deformity, and recurrence, may require tendon transfer or bony correction