Neuropathic Joint

Courtesy: John Ebnezar, Bangalore

NEUROPATHIC JOINT

• A neuropathic joint also known as Charcot’s joint is a progressive and degenerative condition characterised by joint destruction due to loss of normal of sensory innervation.
• This loss of sensation leads to repetitive trauma and microfractures resulting in joint deformity and instability .

Etiology:

Can results from various conditions-

1. Diabetes Mellitus
2. Syringomyelia
3. Tabes dorsalis
4. Leprosy
5. Spinal cord injuries

Joints involved-

1. TMT – 60%
2. MTP
3. Ankle joint
4. Knee joint – rare
5. Shoulder joint – Syringomyelia
6. Hip joint

Clinical presentation:

• Unilateral
• Painless loss of function
• Erythema
• Edema
• Increased temperature
• Unstable ,swollen joint
• Plantar ulcers

Distribution-

• Leading cause of Charcot’s foot- Diabetes Mellitus
• Mid arch is the most common area involved.

Differential Diagnosis-

• Osteomyelitis
• Osteoarthritis

Investigations :

Xray– findings

• Atrophic –osteolysis of distal metatarsals in forefoot
• “licked candy stick “ appearance seen at distal aspect of metatarsal.
• Hypertrophic – characterised by Acute periarticular fracture and joint dislocation.

Bone scans –

• Sensitive indicator of hyperemia
• Surface skin temperature

MRI- features

• Destruction , Dislocation,Distention- edema

Brodsky Classification –(based on location of Charcot’s joint)

• Type 1-       Lisfrank joint 26-60%
• Type 2-       Chopart’s joint and subtalar joint 30-35%
• Type 3A –    Ankle joint
Type 3B-     Posterior calcaneous
• Type 4-       Multiple regions of foot and or ankle
• Type 5-       Forefoot

Treatment

• Acute inflammatory stage –immobilisation
• Resolution stage –accommodative care

1.inlay depth shoes
2.accomodative depth orthoses
3.ankle foot orthoses

• Plantigrade surface not achieved-
Then surgical stabilisation or reconstruction

Non operative measures :

• Activity modification
• Avoid weight bearing
• Total contact casting / bracing

SURGERIES IN CHARCOT FOOT:

1.Exostectomies

2.Reconstruction or Reshaping

• Reshaping of foot eliminates a bony prominence on top or bottom of foot.

3. Limb salvage procedures

• Midfoot arthrodesis
• Triple arthrodesis
• Tibiocalcaneal arthrodesis
• Ankle arthrodesis – for non braceable neuropathic ankle deformity.
ankle involvement leads to ulceration ,osteomyelitis and amputation
Arthrodesis before the ulcerated lesion appears is considered as a limb salvage treatment.

4. External Fixation

• For selected patients ,external fixation after surgical debridement ,considered a reasonable alternarive to below knee amputation.

5. Below knee amputation

When to consider Charcot’s neuropathy?

• Diabetic patient
• Inflamed foot
• Absence of fever
• Elevated CRP or ESR
• In above condition, infection is highly unlikely – hence Charcot process must be considered primarily.