Crossover Toe Deformity

How to Determine Stage Clinically

Stage 1 (Flexible):

• Patient can actively straighten toe
• Passive reduction fully corrects alignment
• No fixed contracture of capsule or EDL
• MTP joint congruent on X-ray

Stage 2 (Semi-rigid):

• Cannot actively correct, but passive reduction partial
• Some capsular contracture present
• EDL tight (requires forced plantar flexion to reduce)
• MTP joint subluxed but not dislocated

Stage 3 (Rigid):

• Cannot reduce passively even with force
• Dorsal capsule severely contracted
• Complete MTP dislocation on X-ray
• May have secondary arthritis

This staging guides treatment selection.

Pathology Commonly Associated

Hallux Valgus:

• Present in 80% of crossover toe cases
• Must be corrected to prevent recurrence
• Perform bunionectomy concomitantly with crossover repair

Second MTP Synovitis:

• Chronic inflammation from plantar plate injury
• Contributes to pain and swelling
• Synovectomy performed during surgery

Transfer Metatarsalgia:

• If third/fourth MTP become symptomatic
• May need additional Weil osteotomies

Intermetatarsal Angle Widening:

• First-second intermetatarsal angle increased
• Addressed with hallux valgus correction

Always assess and address all associated pathology.

Plain X-ray Assessment

Standard Views:

• AP weight-bearing foot: Shows hallux valgus angle, second MTP alignment
• Lateral weight-bearing: Shows dorsal subluxation of second toe
• Oblique foot: Additional detail of MTP joints

Key Measurements:

• Hallux valgus angle (normally under 15 degrees)
• Intermetatarsal angle (1-2, normally under 9 degrees)
• Second MTP alignment (subluxation vs dislocation)
• Relative metatarsal lengths (long second metatarsal)

Findings by Stage:

• Stage 1: Minimal subluxation, joint congruent
• Stage 2: Partial subluxation, joint surfaces losing contact
• Stage 3: Complete dislocation, proximal phalanx dorsal to metatarsal head

Weight-bearing films essential to assess true deformity.

MRI Foot - Plantar Plate Assessment

Indications:

• Uncertain diagnosis (rule out other causes of pain)
• Pre-operative planning for plantar plate repair
• Assessment of plantar plate tear extent

Protocol:

• T1, T2, STIR sequences
• Axial, sagittal, coronal planes
• Small FOV focused on forefoot

Plantar Plate Tear Appearance:

• High T2 signal at insertion (proximal phalanx base)
• Discontinuity of plantar plate substance
• Surrounding edema and inflammation
• May see retraction of torn fibers

Associated Findings:

• Synovitis at second MTP
• Collateral ligament injury
• Bone marrow edema (stress reaction)

MRI confirms plantar plate tear and guides surgical planning.

Additional Modalities

Ultrasound:

• Can assess plantar plate in experienced hands
• Dynamic assessment during toe motion
• Less detailed than MRI
• Operator dependent

CT:

• Rarely indicated
• Useful if assessing bone quality pre-arthrodesis
• Better detail of arthritic changes

Clinical Diagnosis:

• Most cases diagnosed clinically
• Imaging confirms severity and guides treatment

MRI is the imaging modality of choice for soft tissue assessment.

Non-Operative Management

Indicated for:

• Stage 1 (flexible) deformity
• Mild symptoms, minimal functional limitation
• Patient not candidate for surgery

Interventions:

• Buddy taping: Tape second toe to third toe (prevents medial deviation)
• Wide toe box shoes: Reduces dorsal pressure on toe
• Metatarsal pads: Offloads second MTP
• Custom orthotics: Supports metatarsal arch
• NSAIDs: For pain and inflammation

Outcomes:

• 30-40% achieve symptom control
• Does not correct deformity, only prevents progression
• Most progress to Stage 2 and require surgery

Conservative treatment is temporizing for most patients.

Soft Tissue Reconstruction - Standard Approach

Components of Repair:

1. Weil Osteotomy (Metatarsal Shortening):

• Oblique osteotomy of second metatarsal neck
• Shortens metatarsal 3-5mm
• Reduces tension on plantar plate repair
• Allows realignment without excessive force

2. Plantar Plate Repair:

• Expose plantar plate via plantar or dorsal approach
• Identify tear (usually at insertion on proximal phalanx)
• Repair with suture anchors in phalanx base
• Direct side-to-side repair if tissue adequate

3. Flexor-to-Extensor Transfer (FDL Transfer):

• Harvest flexor digitorum longus tendon
• Transfer through interosseous space
• Suture to extensor hood dorsally
• Creates plantar flexion force to balance EDL

4. EDL Lengthening:

• Z-lengthening of extensor digitorum longus
• Releases dorsal contracture
• Allows toe to plantar flex

5. Hallux Valgus Correction:

• Perform concomitant bunionectomy
• Distal chevron or scarf osteotomy
• Removes medial pressure on second toe

Comprehensive approach addresses all components.

Rigid Deformity - Bone Procedures

Options for Rigid (Stage 3) Crossover:

1. Arthrodesis (Fusion) - Preferred:

• Fuse second MTP joint in corrected position
• Excise articular cartilage
• Fixation with plate or K-wires
• Position: 15-20 degrees plantar flexion, neutral medial-lateral
• Outcomes: Reliable pain relief, stable correction

2. Resection Arthroplasty (Salvage):

• Excise proximal phalanx base
• Creates fibrous pseudoarthrosis
• Less stable than fusion
• Used if patient not candidate for fusion (poor bone quality, infection risk)

3. DuVries Arthroplasty:

• Resect proximal half of proximal phalanx
• Preserve joint space
• Historical, less commonly used

Still Require:

• Hallux valgus correction (prevent recurrence)
• May need Weil osteotomy (decompress MTP)

Arthrodesis is gold standard for rigid deformity.

Rehabilitation Protocol

Phase 1 (Weeks 0-2):

• Post-operative shoe with toe platform
• Weight-bearing as tolerated in shoe
• Elevate, ice for swelling
• Pin removal at 2-3 weeks if used for temporary fixation

Phase 2 (Weeks 2-6):

• Continue post-op shoe
• Begin gentle ROM exercises (if soft tissue repair)
• No forced dorsiflexion (protects plantar plate repair)
• Progress to stiff-soled shoe at 4-6 weeks

Phase 3 (Weeks 6-12):

• Transition to wide toe box athletic shoe
• Full weight-bearing
• Progressive strengthening (toe flexion exercises)
• Return to regular shoes at 10-12 weeks

Phase 4 (3-6 months):

• Full activity as tolerated
• May have residual swelling (normal)
• Final outcome assessed at 6 months

Compliance with post-op protocol critical for success.