Validity of a new classification system for Midfoot Charcot Neuroarthropathy to describe the progression of the deformity and guide treatment

M. Tiruveedhula, A. Graham, A. Thapar, S. Dindyal, M. Mulcahy

Introduction: The aim is to describe a new classification system which is sensitive to detect progression of midfoot Charcot deformity and guide treatment based on the stage of the disease.

Patients and methods: The New classification was designed based on clinical and radiological parameters on weight-bearing radiographs. We evaluated the sensitivity of this classification on radiographs of patients who presented to Basildon Diabetic Foot clinic since 2013. Based on the findings, clinical and radiological parameters were charted and early intervention has shown to slow or stabilise the midfoot deformity. Inter-observer and intra-observer reliability was tested using kappa coefficient. A group of 12 experienced members of the MDT were given a set of 10-radiographs to stage the deformity and the process repeated a week later.

Results: We evaluated a set of 256 radiographs and compared the radiographic and clinical findings from patient records. Based on this, a new classification system based on 4 stages was described. In stage 1, the features are similar to Eichenholtz stage 1 with minimal radiographic changes. Stage 2a, where there is a break in Meary’s line but positive cuboid height; clinically have no significant plantar bony prominence. In stage 2b, there is break in Meary’s line with negative cuboid height; clinically have features of ‘Rocker bottom deformity’. Stage 3 is a stage of plantar ulceration, while stage 4 has features of combined midfoot and ankle/subtalar Charcot deformity. Inter-observer agreement was k=0.86 for read 1 and k=0.96 for read 2, indicating excellent inter-observer agreement. Intra-observer agreement ranged from 0.93-1.00 for the double read, indicating excellent intra-observer agreement.

Conclusion: The new classification system is easy to use, reliable, reproducible and sensitive to detect changes in the disease progression. Early intervention such as Tendo-Achilles lengthening has shown to regress the progression of the deformity.