Charcot's
neuroarthropathy
What is it?
- Progressive and destructive condition almost always due to diabetes
mellitus, but can occur in those with chronic alcoholism, syringomyelia,
spina bifida, Hansen’s disease/leprosy, congenital insensitivity
to pain, injuries to the peripheral nerves, meningomyelocele, tabes
dorsalis.
-
First described by Charcot in 1868.
- It is characterised by pathological fractures and/or dislocations
resulting in varying degrees of deformity and functional changes.
The true prevalence and incidence is unknown in diabetes (uncertainty
is primarily due to the definition and criteria for diagnosis)
The prevalence has been reported as varying from 0.15% in which
the criteria was the gross joint changes to 6.8% in which the criteria
were radiological changes in the bone and joints and up to 37% when
bone scans were done in a group of subjects with diabetic neuropathy.
Pathophysiology
Almost always has an underlying neurological deficit –
may have history of trauma.
Eichenholtz (1966) stages:
Stage 1 (stage of development) – acute destruction of joint;
debris formation; capsular distension; ligamentous laxity; subluxation
Stage 2 (stage of coalescence) – absorption of debris; fusion
of fragments to adjacent bone
Stage 3 (stage of reconstruction) – remodelling of bone ends
and fragments
Traditionally
categorised as atrophic or proliferative based on radiographic appearance:
Atrophic
– more common in forefoot. Marked osseous resorption of bone
occurs, resulting in the “sharp pencil” or “sucked
candy” appearance of the metatarsal heads
Proliferative – more common. Tends to affect
the larger joint sin the foot.
Has 3 stages of natural history:
1. Development:
Get a bony fragmentation and osseous debris in the affected joints.
Continued ligamentous injury causes subluxation of the articular
surfaces with further joint incongruity and destruction. Soft tissue
swelling accompanies these injuries.
2. Coalescence:
Typically have a subchondral sclerosis. Increased density in the
area of destruction reflects avascular necrosis and laying down
of new bone on dead trabeculae. The osseous debris is resorbed.
3. Reconstruction:
Characterised by joint fusion
Clinical features:
- Early acute stages – areas of erythema, increased skin temperature,
deformity, instability, often markedly swollen.
- Usually have history of >10 years of diabetes (may have been
poorly controlled)
- Often have history of trauma, but may not recollect it due to
neuropathy.
- Neuropathy almost always present – but pain and discomfort
often is present (but not as much as would be expected given extent
of tissue damage).
- Often hypermobile in early stages
Radiographic
changes:
- Characterised as atrophic (tend to occur early) or hypertrophic
(tend to occur late):
- Atrophic changes – phalangeal “hour glassing”;
metatarsal head osteolysis; ‘mortar and pestle’ deformities;
aggressive osteolysis; osteopenia/bone loss
- Hypertrophic changes – osteochondral fragmentation; intra-articular
debris; marginal osteophytes; periosteal new bone formation; absorption
of debris; ankylosis; healed fractures with callus formation
- Other changes – soft tissue oedema; joint effusions; fractures,
subluxations; deformity
Patterns
of foot involvement:
Appears
to be five characteristic patterns:
Forefoot:
On x-ray usually atrophic and destructive; can mimic osteomyelitis;
plantar ulcers common
Tarsometatarsal:
Characterised by collapse of midfoot
Naviculocuneiform, talonavicular and calcaneocuboid joint:
Characterised by dislocation/disruption of these joints; early findings
are often subtle – osteolytic changes
Calcaneus:
Characterised by avulsion fracture of posterior aspect of calcaneus
Ankle:
Less common than other types; results in severe deformity
Management:
- Nonweightbearing (bed rest; crutches; wheelchair)
- Immobilisation (cast, brace, posterior splint)
- Protected ambulation (therapeutic footwear; orthoses; patella
tendon bearing brace
- Long term prevention – therapeutic footwear (?rockers; foot
orthoses )
- Surgical (exostectomy to preserve skin; fusion in selected cases;
amputation)
Online
resources:
ePodiatry's
links to online articles on Charcot's
neuroarthropathy
ePodiatry's
patient information on Charcot's
foot
Charcot
Foot: The Diagnostic Dilemma - full text article from the American
Family Physician
Charcot
Joints - full text article from the Podiatry Encylopedia at
Curtin University |
