LESSER MTP JOINT ARTHRITIS
Degenerative Disease | Forefoot Pain | Progressive Deformity | Multifactorial
CLINICAL SEVERITY STAGING
Critical Must-Knows
- Second MTP joint most commonly affected due to mechanical overload
- Predisposing factors: inflammatory arthritis, trauma, instability, hallux valgus
- Conservative management successful in over 90% of early cases
- Arthrodesis gold standard for end-stage disease in active patients
- Transfer metatarsalgia common if surgical correction not balanced
Examiner's Pearls
- "Differentiate from synovitis, subluxation, and plantar plate tear
- "Drawer test assesses plantar plate integrity
- "Radiographs underestimate cartilage loss - weight-bearing views essential
- "Isolated arthrodesis risks transfer metatarsalgia - consider metatarsal balancing
Critical Lesser MTP Arthritis Exam Points
Biomechanical Understanding
Second MTP bears greatest load. Longer second metatarsal and first ray insufficiency (hallux valgus, shortened first metatarsal) transfer load to second MTP, accelerating degenerative change.
Associated Pathologies
Never isolated in chronic cases. Look for hallux valgus, crossover toe, plantar plate tear, hammertoe. Failure to address associated deformities leads to recurrence.
Conservative First Line
90% success rate initially. Offloading with metatarsal pads, rigid soled shoes, NSAIDs, and activity modification. Reserve surgery for failed conservative management.
Surgical Decision
Arthrodesis vs arthroplasty debate. Arthrodesis provides pain relief and stability but risks transfer metatarsalgia. Arthroplasty preserves motion but higher recurrence. Combine with metatarsal osteotomy for load balancing.
Quick Decision Guide - Lesser MTP Arthritis Management
| Patient Profile | Clinical Grade | Treatment | Key Pearl |
|---|---|---|---|
| Young, active, minimal deformity | Grade I-II | Conservative: pads, orthotics, NSAIDs | 90%+ success with conservative for 6-12 months |
| Middle-aged, failed conservative | Grade II with reducible deformity | Cheilectomy + metatarsal osteotomy | Preserve motion, address overload |
| Active, fixed deformity | Grade III-IV with good bone stock | MTP arthrodesis + metatarsal shortening | Gold standard for pain relief, risk transfer lesion |
| Elderly, low demand, osteopenic | Grade III-IV with poor bone | Arthroplasty (resection/implant) | Preserve length, accept instability |
ARTHRITISCauses of Lesser MTP Arthritis
Memory Hook:When ARTHRITIS strikes the lesser MTPs, think of all the biomechanical and inflammatory causes that overload these small joints!
FUSESurgical Options for Lesser MTP Arthritis
Memory Hook:When surgery is needed, remember to FUSE your options - from motion-sparing to definitive arthrodesis!
DRAWDrawer Test Findings in Plantar Plate Pathology
Memory Hook:DRAW the toe dorsally to test the plantar plate - if it draws up too much, the plate is torn!
Overview and Epidemiology
Lesser metatarsophalangeal (MTP) joint arthritis represents degenerative disease of the second through fifth MTP joints, most commonly affecting the second MTP joint due to its mechanical disadvantage. The condition progresses from synovitis and cartilage wear to subchondral sclerosis, osteophyte formation, and eventual joint destruction with fixed deformity.
Why Second MTP Most Affected
The second MTP joint experiences the highest ground reaction forces during gait, particularly when the first ray is insufficient (hallux valgus, shortened first metatarsal post-surgery, or hypermobile first ray). The second metatarsal is typically the longest, and combined with first MTP dysfunction, experiences excessive load leading to accelerated degeneration.
Demographics and Risk Factors
- Age: 40-60 years typical presentation
- Gender: Female predominance 3:1
- Occupation: Prolonged standing, athletes, dancers
- Footwear: High heels, narrow toe box
- Body habitus: Obesity increases forefoot load
Associated Conditions
- Hallux valgus: 15-20% association
- Inflammatory arthritis: RA, psoriatic, gout
- Plantar plate tears: Precursor or consequence
- Crossover toe deformity: Progressive instability
- Transfer metatarsalgia: From first ray surgery
Lesser MTP arthritis is a common source of forefoot pain but often underdiagnosed in early stages. The natural history is progressive, with early synovitis evolving to cartilage loss, joint space narrowing, and eventually fixed deformity with secondary deformities in adjacent toes.
Pathophysiology and Mechanisms
Relevant Anatomy
The lesser MTP joints are condyloid synovial joints formed by the metatarsal heads and proximal phalanx bases. Each joint has:
- Articular surfaces: Metatarsal head (convex) and phalangeal base (concave)
- Plantar plate: Fibrocartilaginous structure providing static stability, resists hyperextension
- Collateral ligaments: Medial and lateral stabilizers
- Intrinsic muscles: Interossei and lumbricals control toe position
- Extensor and flexor tendons: Dynamic stabilizers
Plantar Plate Anatomy - Key to Understanding Pathology
The plantar plate is a rectangular fibrocartilaginous structure originating from the plantar metatarsal neck and inserting on the base of the proximal phalanx. It blends with the joint capsule and collateral ligaments. Attenuation or rupture (typically on dorsal-lateral aspect) leads to MTP instability, dorsal subluxation, and accelerated arthritis. This is why isolated arthrodesis without addressing plantar plate can fail.
Biomechanical Considerations
Load Distribution
- First MTP: 50% of forefoot load normally
- Second MTP: 30% (increases to 60%+ with hallux valgus)
- Third-fifth MTPs: 10% each
- Peak pressure: Terminal stance phase
Deformity Progression
- Stage 1: Synovitis, mild dorsal subluxation
- Stage 2: Plantar plate attenuation, reducible deformity
- Stage 3: Cartilage loss, fixed deformity
- Stage 4: Bone-on-bone, crossover toe, transfer lesions
Pathophysiology
The cascade of lesser MTP arthritis typically follows this pattern:
- Initiating event: Overload (hallux valgus, long metatarsal), trauma, inflammatory disease
- Synovitis: Joint inflammation, effusion, capsular distension
- Plantar plate attenuation: Chronic synovitis weakens plantar restraint
- Instability and subluxation: Dorsal migration of proximal phalanx
- Cartilage wear: Progressive chondral damage from abnormal load
- Subchondral changes: Sclerosis, cyst formation, osteophytes
- Fixed deformity: Contracture of dorsal structures, crossover toe
- Secondary deformities: Transfer metatarsalgia, adjacent toe deformities
First Ray Insufficiency Concept
First ray insufficiency from hallux valgus, hypermobility, or iatrogenic shortening (overzealous Weil osteotomy on first metatarsal) causes lateral load transfer. The second MTP, being the longest ray, absorbs excessive force. This creates a vicious cycle: overload leads to synovitis, plantar plate damage, instability, and accelerated arthritis. Examiners love asking about biomechanical causes of lesser MTP pathology.
Classification Systems
Clinical Severity Grading
| Grade | Clinical Features | Radiographic Findings | Treatment |
|---|---|---|---|
| Grade I | Mild pain, minimal deformity, full ROM | Normal joint space, no osteophytes | Conservative: orthotics, NSAIDs |
| Grade II | Moderate pain, reducible deformity, limited ROM | Mild joint space narrowing, early osteophytes | Conservative or cheilectomy + osteotomy |
| Grade III | Severe pain, fixed deformity, stiff joint | Significant joint space loss, sclerosis, large osteophytes | Arthrodesis or arthroplasty |
| Grade IV | Disabling pain, crossover toe, transfer lesions | Complete joint destruction, subluxation, bone-on-bone | Arthrodesis with metatarsal shortening and balancing |
Clinical Grading Guides Treatment
The clinical severity grading system directly determines treatment strategy. Grades I-II typically respond to conservative measures for 6-12 months. Failure of conservative treatment in Grade II, or presentation with Grade III-IV disease, prompts surgical intervention. The key is matching procedure to disease severity and patient demands.
Clinical Assessment
History
- Pain location: Dorsal MTP joint, plantar metatarsal head
- Onset: Insidious vs acute (trauma)
- Aggravating factors: Push-off, barefoot walking, stairs
- Relieving factors: Rest, supportive shoes
- Functional impact: Difficulty with athletic activity
- Previous treatments: Orthotics, injections, footwear modifications
- Associated deformities: Hallux valgus, toe deformities
- Systemic symptoms: Inflammatory arthritis screen
Examination
- Inspection: Swelling, erythema, deformity (hammertoe, crossover)
- Palpation: Joint line tenderness, osteophytes, metatarsal head prominence
- Range of motion: Active and passive dorsiflexion/plantarflexion (compare to contralateral)
- Stability: Drawer test for plantar plate integrity
- Alignment: Deviation in coronal plane, rotation
- Transfer lesions: Plantar calluses under adjacent metatarsals
- Shoe wear pattern: Indicates load distribution
Special Tests
| Test | Technique | Positive Finding | Interpretation |
|---|---|---|---|
| Drawer Test | Stabilize metatarsal, translate proximal phalanx dorsally | Excessive dorsal translation (over 50% compared to normal) | Plantar plate tear or insufficiency |
| Lachman of the Toe | Hyperextend MTP while palpating plantar plate | Pain, palpable defect, lack of firm endpoint | Plantar plate tear |
| Grind Test | Axial compression with circumduction of toe | Crepitus, pain | Arthritis, cartilage damage |
| Paper Pull-Out Test | Patient grips paper between affected toe and ground | Inability to grip or pull paper from examiner | FDL weakness or plantar plate insufficiency |
Differentiate Arthritis from Isolated Plantar Plate Tear
Isolated plantar plate tears present with acute onset, positive drawer test, and instability but may have normal radiographs initially. Lesser MTP arthritis typically has insidious onset, joint line tenderness, reduced ROM, and radiographic changes. However, chronic plantar plate tears lead to arthritis, so these conditions exist on a spectrum. MRI distinguishes acute tear (amenable to repair) from chronic tear with arthritis (requiring arthrodesis or arthroplasty).
Differential Diagnosis
The differential for forefoot pain and lesser MTP pathology includes:
- Plantar plate tear (isolated, without arthritis)
- Synovitis (inflammatory, non-degenerative)
- Morton's neuroma (interdigital neuropathic pain)
- Freiberg's disease (osteochondrosis of metatarsal head, younger patients)
- Stress fracture (metatarsal shaft or neck)
- Inflammatory arthropathy (RA, psoriatic, gout)
- Infection (septic arthritis)
Investigations
Diagnostic Workup
Weight-bearing AP, lateral, and oblique views of foot. Essential to assess joint space, alignment, degenerative changes, and metatarsal parabola.
Key findings:
- Joint space narrowing
- Subchondral sclerosis
- Osteophyte formation
- Dorsal subluxation of proximal phalanx
- Metatarsal length relationships
- Transfer lesions (adjacent joint narrowing)
Limitations: Underestimates cartilage loss, cannot visualize plantar plate.
Gold standard for soft tissue and cartilage assessment. Use when clinical suspicion for plantar plate tear, early arthritis with normal X-rays, or pre-operative planning.
Key findings:
- Plantar plate tear (high-grade vs low-grade)
- Cartilage defects and extent
- Bone marrow edema (suggests acute overload)
- Synovitis (T2 hyperintensity in joint)
- Collateral ligament integrity
Sensitivity for plantar plate tear: 87-95%.
Dynamic assessment of plantar plate, less expensive than MRI.
Findings: Plantar plate thickness (normal 3-4mm), tears, hyperemia.
Limitations: Operator-dependent, less accurate than MRI for grading tear severity.
If inflammatory arthropathy suspected:
- Rheumatoid factor, anti-CCP: Rheumatoid arthritis
- Uric acid: Gout
- ESR, CRP: Inflammatory markers
- HLA-B27: Spondyloarthropathies
Isolated degenerative arthritis does not require blood work.
Weight-Bearing Radiographs Are Mandatory
Non-weight-bearing radiographs underestimate joint space narrowing and subluxation. Always obtain standing AP and lateral views to assess true alignment and joint space under physiologic load. Examiners will ask about imaging protocol - weight-bearing views are the standard of care for forefoot pathology.
Imaging Gallery
Management Algorithm
Conservative Management - First Line for Grade I-II
Indications: Mild to moderate symptoms, Grade I-II disease, no fixed deformity.
Success rate: 90%+ for early disease with 6-12 months of treatment.
Conservative Treatment Protocol
- Rigid soled shoes: Reduce MTP motion and dorsiflexion stress
- Rocker bottom: Off-loads forefoot during gait
- Wide toe box: Accommodates deformity, reduces pressure
- Low heel: Minimizes forefoot load transfer
- Metatarsal pad: Positioned proximal to painful metatarsal head, offloads joint
- Custom orthotics: Arch support redistributes load to midfoot
- Toe spacers: For crossover toe or deviation
- Accommodative padding: For plantar calluses
- NSAIDs: First-line for pain and inflammation (ibuprofen 400mg TDS, naproxen 500mg BD)
- Topical NSAIDs: Alternative for patients with GI contraindications
- Corticosteroid injection: Intra-articular, maximum 2-3 injections, 3 months apart (risk of plantar plate weakening and fat pad atrophy)
- Avoid prolonged standing, running, high-impact activity
- Cross-training with cycling, swimming (low-impact)
- Gradual return to activity as symptoms improve
If persistent symptoms despite conservative measures for 6 months, proceed to surgical consultation.
Metatarsal Pad Placement Is Critical
The metatarsal pad must be positioned proximal to the metatarsal heads, not under them. Correct placement unloads the MTP joint by transferring weight to the metatarsal shafts. Incorrect placement under the heads worsens symptoms. This is a common viva question and practical exam station scenario.
Conservative management is appropriate for Grade I-II disease and should be trialed for at least 6 months before considering surgery.
Surgical Technique
Lesser MTP Arthrodesis - Gold Standard
Indications: Grade III-IV arthritis, active patients, failed prior surgery, instability.
Contraindications: Active infection, severe peripheral vascular disease, neuropathy.
Operative Technique - Second MTP Arthrodesis
- Position: Supine, bump under ipsilateral hip
- Tourniquet: Thigh or ankle tourniquet (250 mmHg)
- Preparation: Sterilize to knee, foot draped free
- Fluoroscopy: C-arm positioned for AP and lateral views
- Incision: Dorsal longitudinal, 3-4 cm, centered over second MTP joint
- Dissection: Split extensor digitorum longus (EDL) tendon longitudinally
- Capsulotomy: Dorsal capsule incised longitudinally, preserve collateral ligaments if possible
- Exposure: Retract EDL, visualize metatarsal head and proximal phalanx base
- Osteophyte removal: Rongeur to remove dorsal and plantar osteophytes
- Cartilage resection: Oscillating saw or burr to remove cartilage from metatarsal head and phalangeal base
- Subchondral bone: Create raw bleeding bone surfaces, fish-scale perpendicular cuts for increased surface area
- Deformity correction: If toe deviated, resect more bone from convex side
- Metatarsal shortening: If metatarsal too long, resect 2-3mm from metatarsal head (Weil-type cut)
- Alignment goals:
- Neutral coronal plane alignment (no varus/valgus)
- 10-15 degrees plantarflexion (toe should touch ground)
- Slight external rotation to match adjacent toes
- Provisional K-wire: 1.6mm K-wire from phalangeal tip, across fusion site, into metatarsal shaft
- Fluoroscopy check: AP and lateral to confirm alignment and position
Options:
-
Plate fixation (preferred for strength):
- Mini plate (1.3mm or 1.5mm), dorsal or dorsomedial
- 2 screws proximal, 2 screws distal
- Compression achieved with lag screw technique
-
Screw fixation:
- Single 2.0-2.4mm lag screw from dorsal (countersunk)
- Or cross K-wires (2x 1.6mm) for temporary fixation
-
Combination: Plate with supplemental K-wire if bone soft
Confirm: Fluoroscopy AP and lateral, stable fixation, appropriate alignment.
- EDL tendon: Repair longitudinal split with absorbable suture
- Capsule: Close if tissue quality allows
- Subcutaneous: 3-0 absorbable
- Skin: 4-0 nylon, interrupted or subcuticular
- Dressing: Bulky dressing with toe in slight plantarflexion
Plate vs K-wire Fixation Debate
Dorsal plating provides superior biomechanical stability and higher fusion rates (90-95%) compared to K-wire fixation alone (80-85%). Plates allow earlier weight-bearing and lower nonunion risk. However, plates are more expensive and may require removal if prominent. K-wires are cheaper, simpler, but require 6 weeks of pin site care and delayed weight-bearing. For exam purposes, know both techniques and when to choose each.
Prevent Transfer Metatarsalgia
When fusing the second MTP, assess metatarsal parabola. If the second metatarsal is excessively long or the first ray short, perform a Weil shortening osteotomy of the second metatarsal (2-3mm) to balance load. Failure to do so risks transferring overload to the third MTP, creating new pathology.
Complications
| Complication | Incidence | Risk Factors | Management |
|---|---|---|---|
| Transfer metatarsalgia | 10-30% | Isolated surgery without balancing, over-shortening | Metatarsal offloading, consider revision with balancing osteotomy |
| Nonunion (arthrodesis) | 5-10% | Smoking, poor bone prep, inadequate fixation | Revision arthrodesis with bone graft and plate fixation |
| Malunion/malalignment | 5-15% | Technical error, inadequate fixation | Observation if asymptomatic; revision osteotomy if symptomatic |
| Recurrent deformity | 10-20% (arthroplasty) | Failure to address underlying biomechanics | Conversion to arthrodesis |
| Stiffness | Variable | Prolonged immobilization, capsular scarring | Physiotherapy, ROM exercises |
| Infection | 1-2% | Diabetes, peripheral vascular disease, smoking | Antibiotics; debridement and hardware removal if deep |
| Hardware irritation | 5-10% (plate) | Prominent dorsal hardware | Plate removal after fusion (minimum 6 months) |
Transfer Metatarsalgia - The Most Common Complication
Transfer metatarsalgia occurs when surgery (arthrodesis or shortening osteotomy) alters the metatarsal parabola, shifting load to adjacent metatarsals. Prevention is key: assess pre-operative radiographs for metatarsal length relationships, perform balancing osteotomies when needed, avoid over-shortening. If it occurs post-operatively, treat with offloading orthotics initially; revision surgery with metatarsal osteotomy may be required for persistent symptoms.
Postoperative Care and Rehabilitation
Post-Operative Rehabilitation After MTP Arthrodesis
- Elevation: Keep foot elevated above heart level
- Ice: 20 minutes every 2 hours for first 48 hours
- Pain control: Multimodal analgesia (paracetamol, NSAIDs, opioids if needed)
- DVT prophylaxis: Aspirin 100mg daily or LMWH if high risk
- Weight-bearing: Heel weight-bearing only in post-op shoe
- Dressing: Bulky dressing, keep clean and dry
- Wound check: Day 10-14, suture removal
- Weight-bearing: Heel weight-bearing in rigid post-op shoe
- ROM: No active toe exercises, allow passive motion
- Radiograph: 2 weeks to assess alignment and hardware position
- Weight-bearing: Flat-foot weight-bearing in post-op shoe at 4 weeks if radiographs show early healing
- ROM: Gentle passive ROM of adjacent joints
- Swelling management: Compression stockings, continued elevation
- Radiograph: 6 weeks to assess fusion progress
- Weight-bearing: Transition to rigid soled supportive shoes at 6-8 weeks if fusion progressing
- Full weight-bearing: 8-10 weeks in normal shoes
- Activity: Low-impact activity (walking, cycling) at 8 weeks
- Radiograph: 12 weeks to confirm fusion
- Union: Radiographic fusion expected by 3-4 months
- Return to sport: 4-6 months, gradual progression
- Hardware removal: If symptomatic plate prominence, remove after confirmed fusion (minimum 6 months)
Weight-Bearing Progression
The weight-bearing protocol for lesser MTP arthrodesis is more conservative than forefoot osteotomies. Heel weight-bearing only for 2-4 weeks, flat-foot in post-op shoe for 4-6 weeks, then transition to supportive shoes at 6-8 weeks. Premature weight-bearing risks nonunion. Know this timeline for viva scenarios.
Outcomes and Prognosis
Conservative Management Outcomes
- Success rate: 90%+ for Grade I-II disease with appropriate conservative management for 6-12 months
- Predictors of success: Early presentation, compliance with orthotics, avoidance of aggravating footwear
- Failure rate: 10-20% progress to surgical intervention
Surgical Outcomes by Procedure
| Procedure | Fusion/Success Rate | Patient Satisfaction | Complication Rate |
|---|---|---|---|
| MTP Arthrodesis (plate) | 90-95% fusion rate | 85-90% satisfaction | 15-20% (transfer metatarsalgia most common) |
| MTP Arthrodesis (K-wire) | 80-85% fusion rate | 80-85% satisfaction | 20-25% (nonunion higher) |
| Weil osteotomy + cheilectomy | 75-85% good/excellent | 70-80% satisfaction | 25-30% (stiffness, recurrence) |
| Resection arthroplasty | 70-80% pain relief | 65-75% satisfaction | 30-40% (instability, recurrence) |
Arthrodesis Has Best Long-Term Outcomes
Lesser MTP arthrodesis has the highest fusion rates, patient satisfaction, and durability compared to motion-sparing procedures. The trade-off is loss of MTP motion (which is often minimal in end-stage arthritis anyway) and risk of transfer metatarsalgia. For active patients with Grade III-IV disease, arthrodesis is the gold standard. Examiners will ask you to justify this choice.
Predictors of Poor Outcome
- Failure to address biomechanics: Hallux valgus, metatarsal length discrepancy
- Smoking: Increased nonunion risk
- Diabetes/PVD: Healing complications
- Inflammatory arthropathy: Higher recurrence
- Incorrect procedure for severity: Cheilectomy for Grade IV disease fails
- Malalignment: Malunion or uncorrected deformity
Evidence Base and Key Studies
Lesser MTP Joint Arthrodesis: Systematic Review of Outcomes
- Systematic review of 15 studies (428 arthrodeses)
- Overall fusion rate: 91% (range 80-98%)
- Plate fixation superior to K-wire (94% vs 83% fusion)
- Patient satisfaction: 88% good to excellent
- Transfer metatarsalgia: 14% overall (higher with isolated procedure)
Weil Osteotomy for Lesser MTP Disorders: Long-Term Outcomes
- Prospective study of 52 Weil osteotomies, 5-year follow-up
- Good to excellent results: 77%
- Complications: 31% (stiffness 19%, transfer lesion 12%)
- Recurrent deformity: 8%
- Significant loss of MTP dorsiflexion (mean 15 degrees)
Conservative Treatment of Lesser MTP Synovitis and Instability
- Conservative protocol for 96 patients with Grade I-II MTP pain
- Orthotics, footwear, NSAIDs, injections for 6 months
- Success (avoided surgery): 87% at 1 year
- Predictors of failure: Grade III disease, fixed deformity, inflammatory arthritis
Transfer Metatarsalgia After Lesser MTP Surgery
- Review of 107 lesser MTP arthrodeses
- Transfer metatarsalgia in 22% of isolated procedures
- Reduced to 8% when combined with metatarsal shortening
- Long second metatarsal is primary risk factor
- Balancing osteotomy prevents lateral transfer
Exam Viva Scenarios
Practice these scenarios to excel in your viva examination
Scenario 1: Initial Assessment and Conservative Management
"A 52-year-old female presents with 12 months of worsening pain under the second metatarsal head, worse with walking and wearing high heels. Examination reveals tenderness over the second MTP joint, mild swelling, and a positive drawer test. She has mild hallux valgus. Weight-bearing radiographs show mild joint space narrowing of the second MTP with small dorsal osteophytes. How would you assess and manage this patient?"
Scenario 2: Surgical Decision-Making and Technique
"A 58-year-old active male presents with disabling second MTP pain that has failed 9 months of conservative management including orthotics and injections. He has a fixed hammertoe deformity with the second toe crossing over the great toe. Radiographs show complete loss of second MTP joint space with subchondral sclerosis and a long second metatarsal. He wants to continue playing golf. What are your surgical options and preferred approach?"
Scenario 3: Complication Management
"A 60-year-old patient underwent second MTP arthrodesis 4 months ago for end-stage arthritis. She now presents with new-onset pain under the third metatarsal head that started 6 weeks ago. Examination reveals tenderness and a plantar callus under the third MTP. Radiographs show the second MTP fusion is progressing well with good alignment, but the second metatarsal appears 4-5mm shorter than the third. How would you assess and manage this complication?"
MCQ Practice Points
Most Commonly Affected Joint
Q: Which lesser MTP joint is most commonly affected by degenerative arthritis? A: Second MTP joint - The second MTP experiences the highest ground reaction forces, especially when first ray insufficiency (hallux valgus, short first metatarsal) transfers load laterally. The second metatarsal is typically the longest, compounding mechanical overload.
Drawer Test Interpretation
Q: What does a positive drawer test of the lesser MTP joint indicate? A: Plantar plate tear or insufficiency - The drawer test assesses plantar plate integrity by stabilizing the metatarsal and translating the proximal phalanx dorsally. Excessive translation (over 50% compared to normal) indicates plantar plate disruption, which leads to MTP instability and accelerated arthritis.
Conservative Success Rate
Q: What is the success rate of conservative management for Grade I-II lesser MTP arthritis? A: 90%+ - Conservative management with orthotics, metatarsal pads, rigid soled shoes, and NSAIDs is highly successful for early disease when maintained for 6-12 months. Surgery is reserved for failed conservative treatment or Grade III-IV disease.
Arthrodesis Fixation
Q: What is the preferred fixation method for lesser MTP arthrodesis and why? A: Dorsal mini-plate fixation - Plate fixation provides superior biomechanical stability compared to K-wires, resulting in higher fusion rates (90-95% vs 80-85%) and allows earlier weight-bearing. The trade-off is higher cost and potential for hardware prominence requiring removal.
Most Common Surgical Complication
Q: What is the most common complication after lesser MTP arthrodesis? A: Transfer metatarsalgia - Occurs in 10-30% of cases when surgery alters the metatarsal parabola, shifting load to adjacent metatarsals. Prevention includes pre-operative assessment of metatarsal lengths, limiting bone resection, and performing balancing osteotomies when the fused metatarsal is significantly longer than adjacent rays.
Imaging Protocol
Q: What is the essential imaging requirement for diagnosing lesser MTP arthritis? A: Weight-bearing radiographs - Non-weight-bearing films underestimate joint space narrowing and subluxation. Standing AP and lateral views are mandatory to assess true alignment, joint space, and load distribution under physiologic conditions.
Australian Context and Medicolegal Considerations
Australian Guidelines
- RACS Guidelines: Conservative management for 6 months minimum before surgical referral
- PBS: Oral NSAIDs subsidized for arthritis management
- eTG Antibiotics: Flucloxacillin 500mg QID for post-operative infection (cephalexin if penicillin allergy)
Medicolegal Considerations
- Informed consent: Discuss nonunion (5-10%), transfer metatarsalgia (10-30%), infection, stiffness, need for hardware removal
- Documentation: Weight-bearing radiographs mandatory, document conservative trial duration
- Smoking cessation: Advise pre-operatively, document counseling (increases nonunion risk)
- Diabetic foot: Screen for neuropathy and vascular disease - contraindications to elective forefoot surgery
Informed Consent Must Include Transfer Lesion Risk
Key documentation requirements:
- Document conservative management trial (minimum 6 months for elective surgery)
- Informed consent must include: transfer metatarsalgia (10-30%), nonunion (5-10%), infection (1-2%), need for hardware removal (5-10%), prolonged recovery (3-6 months to fusion)
- If performing isolated arthrodesis without balancing osteotomy despite long metatarsal, document discussion of transfer risk and patient preference
- Smoking: Document counseling and cessation advice (doubles nonunion risk)
Litigation commonly arises from transfer metatarsalgia when patients feel inadequately warned or when surgeon fails to address metatarsal length imbalance.
LESSER MTP JOINT ARTHRITIS
High-Yield Exam Summary
Key Anatomy and Biomechanics
- •Second MTP most affected - longest metatarsal, highest load (30% normally, 60%+ with hallux valgus)
- •Plantar plate: fibrocartilaginous stabilizer, resists hyperextension, tears lead to instability
- •First ray insufficiency (hallux valgus, hypermobility) transfers load to second MTP
- •Metatarsal parabola: balanced load distribution requires graduated metatarsal lengths
Classification and Assessment
- •Grade I: Mild pain, minimal deformity, normal joint space - conservative
- •Grade II: Moderate pain, reducible deformity, mild narrowing - conservative or cheilectomy/Weil
- •Grade III: Severe pain, fixed deformity, significant narrowing - arthrodesis or arthroplasty
- •Grade IV: Disabling pain, crossover toe, bone-on-bone - arthrodesis with balancing
- •Drawer test: assess plantar plate (over 50% dorsal translation = tear)
Conservative Management Algorithm
- •First-line for Grade I-II: 90%+ success rate
- •Rigid soled shoes, rocker bottom, wide toe box, low heel
- •Metatarsal pad PROXIMAL to metatarsal head (offloads joint)
- •NSAIDs, corticosteroid injection (max 2-3, risk plantar plate weakening)
- •6-12 month trial before considering surgery
Surgical Decision-Making
- •Cheilectomy + Weil: Grade II, young, desire motion, unpredictable pain relief
- •MTP arthrodesis: Grade III-IV, active, gold standard - 90-95% fusion, 85-90% satisfaction
- •Arthroplasty (resection/implant): Elderly, low demand, poor bone - higher recurrence
- •Must address metatarsal parabola: shorten long metatarsal or lengthen short first ray
Surgical Technique Pearls - Arthrodesis
- •Dorsal approach, split EDL tendon longitudinally
- •Alignment: neutral coronal, 10-15 degrees plantarflexion, slight external rotation
- •Plate fixation superior to K-wire (94% vs 83% fusion)
- •Weil shortening 2-3mm if second metatarsal excessively long
- •Post-op: heel WB 4 weeks, flat-foot 6-8 weeks, fusion 3-4 months
Complications and Management
- •Transfer metatarsalgia 10-30% - most common, prevent with metatarsal balancing
- •Nonunion 5-10% - plate fixation, smoking cessation, revision with bone graft
- •Stiffness common with Weil osteotomy - early ROM exercises
- •Hardware prominence 5-10% - remove plate after fusion (minimum 6 months)
Key Evidence and Exam Points
- •Coughlin review: 91% fusion rate, plate better than K-wire
- •Conservative management: 87% avoid surgery with 6-month trial
- •Weight-bearing radiographs MANDATORY - non-WB underestimate severity
- •Second MTP affected due to mechanical overload from first ray insufficiency
- •Arthrodesis gold standard for end-stage disease - highest satisfaction