Plantar Pressure and Radiographic Deformity at Diagnosis of Active Charcot Neuro-Osteoarthropathy as Potential Prognostic Markers for Time to Remission.

Background

Active Charcot neuro-osteoarthropathy (CNO) requires prolonged offloading, yet no reliable markers exist to predict time to remission at diagnosis. This study examined whether plantar pressure and radiographic deformity at diagnosis are associated with time to remission, and whether these measures provided independent and complementary prognostic value.

Methods

This retrospective cohort study included 20 adults with active CNO. Barefoot peak plantar pressure and five radiographic angles from weight-bearing lateral radiographs were assessed at diagnosis. Associations with time to remission were examined using Spearman correlation and receiver operating characteristic (ROC) analysis.

Results

Median time to remission was 132 days (interquartile range [IQR] 102 to 155). Medial midfoot plantar pressure showed a moderate non-significant association with time to remission (ρ 0.42, p = 0.064, area under the curve (AUC) 0.71). Of three radiographic angles with significant associations after false discovery rate correction, talar declination showed the strongest association with time to remission (ρ 0.76, p < 0.001) and demonstrated good discriminative performance for delayed remission (AUC: 0.89, 95% CI: 0.74 to 1.00). Meary's angle performed comparably (AUC 0.86, 95% CI 0.69 to 1.00), consistent with high collinearity between measures (ρ = -0.94). Adding plantar pressure to talar declination did not improve discriminative performance (combined AUC 0.89, DeLong p = 1.00).

Conclusions

In this exploratory cohort, talar declination and Meary's angle demonstrated good discriminative performance for delayed remission. Plantar pressure showed a positive association with time to remission that did not reach statistical significance and did not improve discriminative performance when combined with radiographic assessment. Radiographic measurement at diagnosis, specifically talar declination or Meary's angle, may support prognostic discussions with patients and inform decisions around offloading duration, pending prospective validation.