Current Insights On Classifying Charcot Arthropathy
This staging system is known as the Eichenholtz classification and has become widely accepted. This classification system is based primarily on radiographic changes. Therefore, it neglects the initial inflammatory phase in which there are no bone changes visible on plain radiographs.
Later, Shibata, et al., added a stage (Stage 0) to the Eichenholtz classification. This stage describes warmth, dull pain, swelling and joint instability, with normal appearing bone and joints on radiographs.14 Yu and Hudson described Stage 0 Charcot as an acute sprain or fracture in the presence of neuropathy, and the authors reviewed the evaluation and treatment of this stage in the Charcot foot and ankle.15
Sella and Barrette developed an anatomic classification scheme which includes a “pre-radiographic” clinical Stage 0, consisting of localized heat and swelling.16 Armstrong and Lavery introduced a practical, two-part staging system, indicating that the foot is either “acute” or “post-acute (quiescent).”17
Pertinent Points On The Sanders/Frykberg System
Several authors have developed anatomically based classification systems by observing the patterns of involvement in the foot and ankle.16,18-20Sanders and Frykberg classified Charcot arthropathy anatomically into patterns of joint involvement.18 The authors divided the foot and ankle into five patterns of destruction.
Pattern I involves the forefoot joints and common radiographic changes include osteopenia, osteolysis, juxta-articular cortical bone defects, subluxation and destruction.
Pattern II involves the tarsometatarsal joints including the metatarsal bases, cuneiforms and cuboid. Involvement at this location may present as subluxation or fracture/ dislocation, and it frequently results in the classic rocker bottom foot deformity.
Pattern III involves Chopart’s joint or the naviculocuneiform joints. Radiographic changes typically show osteolysis of naviculocuneiform joints with fragmentation and osseous debris dorsally and plantarly.
Pattern IV involves the ankle with or without subtalar joint involvement. Radiographs reveal erosion of bone and cartilage with extensive destructive of the joint, which may result in complete collapse of the joint and dislocation. Typically, this pattern of involvement results in a severe unstable deformity.
Pattern V is isolated to the calcaneus and usually results from an avulsion of the Achilles tendon off the posterior tubercle. The authors reported the midfoot (patterns II and III) to be the most common area of involvement and these patterns are often associated with plantar ulceration at the apex of the deformity.18
A Primer On The Brodsky And Rouse Classification
Similarly, Brodsky and Rouse described four distinct anatomical areas of the foot and ankle that are most commonly affected by Charcot arthropathy.19
Type 1 accounts for up to 70 percent of cases and involves the metatarsocuneiform and naviculocuneiform joints (midfoot). This midfoot involvement often leads to a rocker bottom foot with symptomatic bony prominences and often results in skin breakdown plantarly at the apex of the deformity.
Type 2 involves the subtalar, talonavicular or calcaneocubiod joints (hindfoot), and accounts for up to 20 percent of the cases. Type 3 is divided into “A” (ankle) and “B” (posterior calcaneus). This type affects approximately 10 percent of patients and occurs mainly in the ankle. Type 2 and type 3 involvements are most likely to result in instability.
This classification system fails to include multiple regions of involvement. Most notably, it does not include the forefoot and has been modified to include Type 4 (multiple regions) and Type 5 (forefoot).21