Hallux Rigidus for the FRCSOrth

Courtesy: Baljinder Dhinsa, FRCS Tr and Orth, Kent, UK

Definition

• Hallux rigidus is a painful degenerative condition of the first metatarsophalangeal (MTP) joint.
• Characterized by:
  • Restricted range of motion, especially dorsiflexion
  • Periarticular osteophyte formation
  • Progressive degenerative arthritis of the first MTP joint
• First described in 1887.
• Other related terms:
  • Hallux limitus
  • Dorsal bunion
  • Metatarsus primus elevatus
• Hallux rigidus is preferred because it reflects global stiffness rather than isolated limitation.

Epidemiology

• Most common arthritic condition of the foot.
• May occur in:
  • Adolescents (often associated with osteochondral defects)
  • Adults (usually degenerative arthritis).
• Studies report familial predisposition:
  • Up to 50% family history in adolescents.
  • Approximately 80% of patients may report family history of great toe disorders.
  • Bilateral involvement is common.

Etiology

The exact cause remains unclear.

Trauma

• Acute trauma
  • Hyperextension injury of the first MTP joint.
  • Impaction of the proximal phalanx against the metatarsal head.
• Repetitive microtrauma
  • Leads to progressive cartilage damage.

Proposed Anatomical Associations (not proven)

• Flattened or squared metatarsal head
• Long or short first metatarsal
• Tight intrinsic muscles
• Pes planus
• Hindfoot pronation
• Congruent first MTP joint

Evidence for these associations remains inconclusive.

Clinical Features

History

Patients commonly complain of:

• Pain in the first MTP joint
• Swelling in early stages
• Progressive stiffness
• Reduced dorsiflexion
• Pain during:
  • Walking
  • Push-off phase of gait
• Difficulty wearing shoes due to:
  • Dorsal bony prominence
  • Shoe friction over osteophytes

Neurological symptoms

• Compression of dorsal cutaneous nerve
• May cause:
  • Tingling
  • Hyperesthesia
  • Local irritation

Associated symptoms

• Transfer metatarsalgia
• Development of hallux valgus deformity
• Secondary soft-tissue irritation

Clinical Examination

General Examination

Follow standard FRCS foot examination:

• Assess gait
• Inspect footwear
• Look for orthoses
• Examine wear patterns

Foot Alignment

Assess:

• Hindfoot
• Midfoot
• Forefoot alignment

Local Examination

Early Disease

• Synovial thickening
• Mild swelling

Progressive Disease

• Dorsal osteophytes
• Bony prominence (often dorsolateral)
• Reduced range of motion

Movement

• Marked restriction of dorsiflexion
• Pain with:
  • Dorsiflexion (bony impingement)
  • Plantarflexion (capsular stretching)

Neurological Signs

• Irritation of dorsal digital nerve
• Possible Tinel-like sign

Vascular and Neurological Assessment

• Palpate peripheral pulses
• Assess sensory function

Imaging

Plain Radiographs (Essential)

Weight-bearing:

• AP view
• Lateral view
• Medial oblique view

Lateral View

• Dorsal osteophytes
• Spur formation resembling “candle wax” projection

Oblique View

• Useful when AP view is obscured by osteophytes
• Helps assess true joint space

AP View Findings

Early stage:

• Non-uniform joint space narrowing
• Early osteophyte formation

Advanced stage:

• Subchondral sclerosis
• Subchondral cysts
• Osteophytes
• Enlargement of proximal phalanx base

MRI

Indications:

• Early disease
• Suspected osteochondral defect
• Cartilage evaluation

CT Scan

• Limited role in routine assessment.

Ultrasound

• Rarely required.

Bone Scan

• No routine role.

Pathophysiology of Degenerative Changes

• Disease begins with cartilage and chondrocyte dysfunction.
• Early stages:
  • Chondrocyte proliferation
  • Release of inflammatory mediators:
    • Interleukin-1
    • Tumor necrosis factor
• These inhibit:
  • Proteoglycan synthesis
  • Type II collagen production

Cartilage Changes

• Increased water content
• Decreased proteoglycans
• Cartilage becomes:
  • Soft
  • Friable
  • Fissured

Progressive Degeneration

• Cartilage fragmentation
• Exposure of subchondral bone
• Development of:
  • Subchondral cysts
  • Osteophytes
  • Synovial inflammation

Classification (Coughlin and Shurnas)

Grades 0–4 based on:

• Range of motion
• Radiographic changes
• Clinical symptoms

Key Concept

• Early disease ? pain predominant
• Advanced disease ? stiffness predominant

Non-Operative Management

Trial period: 6 months to 1 year

Footwear Modification

• Wide toe-box shoes
• Stiff-soled shoes
• Rocker-bottom soles

Orthoses

• Carbon fibre plate
• Morton’s extension

Purpose:

• Reduce first MTP joint motion.

Medications

• NSAIDs
• Topical anti-inflammatory gels

Injections

• Corticosteroid injections
  • Temporary relief (up to ~6 months)
• Hyaluronic acid injections
  • Limited evidence of benefit.

Surgical Management

Indicated when conservative treatment fails.

Cheilectomy

Indications

• Grade I–II (early disease)

Procedure

• Removal of:
  • Dorsal one-third of metatarsal head
  • Osteophytes
  • Dorsal proximal phalanx osteophytes

First described by DuVries (1959).

Outcomes

• Pain relief in ~90–97% of patients
• Limited improvement in ROM
• Realistic postoperative dorsiflexion:
  • ~40°

Advantages

• Day-case procedure
• Early weight-bearing
• Quick recovery

Limitations

• May progress to arthritis
• Revision to arthrodesis occasionally required.

Moberg Osteotomy

Procedure

• Dorsiflexion osteotomy of proximal phalanx
• Often combined with cheilectomy.

Indications

• Grade I–II disease

Outcomes

• Satisfaction rates up to ~99%

Limitation

• Difficult conversion to arthrodesis later due to altered anatomy.

Keller Resection Arthroplasty

Procedure

• Resection of base of proximal phalanx

Complications

• Weak push-off
• Transfer metatarsalgia
• Cock-up deformity

Due to these complications, the procedure is less commonly used today.

Interposition Arthroplasty

Modification of Keller procedure.

• Limited bone resection
• Interposition using:
  • Capsule
  • Tendon
  • Muscle

Limitations

• Persistent weakness
• Transfer metatarsalgia
• Declining popularity.

Arthroplasty (Implants)

Types

• Silastic implants
• Metal implants
• Ceramic implants
• Synthetic cartilage implants

Problems with Early Implants

• Osteolysis
• Implant subsidence
• High revision rates.

Synthetic Cartilage Implant (Cartiva)

• Synthetic hydrogel implant
• Placed in metatarsal head defect.

Advantages

• Preserves bone stock
• Easier conversion to arthrodesis.

Outcomes

• Good short-term results
• ~9% revision rate at 2 years.

Long-term data still limited.

Arthrodesis (Gold Standard)

First MTP joint fusion is considered the most reliable treatment.

Indications

• Grade III–IV disease
• Severe arthritis
• Rheumatoid arthritis
• Neuromuscular disorders
• Failed previous surgery.

Optimal Fusion Position

• 10–15° dorsiflexion relative to floor
• 20–25° dorsiflexion relative to first metatarsal
• 5–15° valgus

Toe tip should:

• Touch the floor
• Allow slight lift under the toe.

Fixation Techniques

• Crossed lag screws
• Lag screw + dorsal plate
• Locking compression plate
• Compression staples

Biomechanically strongest construct

• Lag screw + dorsal plate

Outcomes of Arthrodesis

Literature reports:

• >90–96% patient satisfaction
• High union rates
• Low revision rates.

Functional outcomes:

• 92% return to hiking
• 80% return to golf
• 75% return to tennis
• 75% return to jogging.

Practical Surgical Approach (Common Practice)

Typical surgeon preference:

• Stage I ? Cheilectomy
• Stage II ? Cheilectomy ± Moberg osteotomy
• Stage III–IV ? First MTP arthrodesis