Peritalar Subluxation in Progressive Collapsing Foot Deformity

What is it about?

This study evaluated radiographic parameters of peritalar subluxation in patients with progressive collapsing foot deformity (PCFD) who had valgus ankle involvement (Class E) and compared them to patients with PCFD without ankle valgus. The results showed that peritalar subluxation was significantly less pronounced in the ankle valgus group. The findings suggest that peritalar subluxation might occur first in PCFD, potentially around the subtalar and midtarsal joints, increasing the load on the deltoid ligament. When this overload leads to proximal failure and a valgus talar tilt, peritalar subluxation surprisingly reduces despite underlying peritalar ligamentous incompetence. The study concluded that MFS values were significantly lower in patients with PCFD and valgus ankle and did not correlate with overall malalignment. Therefore, MFS should not be used as an imaging parameter to evaluate and stage Class E patients. A high probability of ankle valgus deformity was associated with FAO values of ‡12.14% in PCFD.

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Why is it important?

The study is important because it sheds light on the impact of ankle valgus deformity on the assessment of peritalar subluxation in patients with progressive collapsing foot deformity (PCFD). Understanding the differences in radiographic parameters between patients with and without ankle valgus helps in accurately diagnosing and staging the condition. Key Takeaways: 1. Ankle valgus deformity in PCFD patients affects the measurement of peritalar subluxation, making it an imprecise disease parameter in this scenario. 2. MFS is not a reliable parameter for evaluating and staging Class E patients with PCFD and ankle valgus. 3. FAO values of =12.14% are a strong indicator of ankle deformity in patients with PCFD. 4. The study highlights the importance of considering ankle valgus deformity when assessing and managing PCFD.