Sensitivity and Tests for Evaluation of Plantar Fasciopathy

Plantar fasciopathy (PF) is one of the most common causes of foot pain, affecting a substantial proportion of the population במהלך their lifetime. It is characterized by pain and structural alterations at the proximal insertion of the plantar fascia on the calcaneus. The term "plantar fasciopathy" is preferred over "plantar fasciitis," as degenerative tissue changes and thickening are considered to predominate over inflammatory processes.

The pathogenesis of PF remains incompletely understood but is thought to involve the gastrocnemius muscle within an integrated biomechanical unit that includes the triceps surae complex, the calcaneus, and the plantar fascia. PF has a relevant clinical and socioeconomic impact, affecting quality of life and functional capacity, particularly in individuals exposed to prolonged standing or weight-bearing activities. Although most patients respond to conservative treatment, a subset develops persistent or refractory symptoms.

Diagnosis is primarily clinical, based on patient history and physical examination. Imaging modalities such as ultrasound and magnetic resonance imaging are mainly used to exclude alternative causes of heel pain. However, the relationship between imaging findings and symptom severity remains inconsistent, and there is currently no simple, standardized clinical test with established diagnostic accuracy for PF. The availability of a reliable bedside test capable of distinguishing PF from other causes of heel pain would improve diagnostic efficiency and clinical decision-making.

Given the anatomical and biomechanical relationship between the Achilles tendon and the plantar fascia, and their shared association with gastrocnemius tightness, adapting a clinical test originally developed for Achilles tendon assessment may provide a useful diagnostic approach. A method based on pain modification during active ankle dorsiflexion, which alters mechanical tension, may be transferable to the plantar fascia with appropriate modification.

This study is designed as an exploratory diagnostic investigation aimed at evaluating the performance of two clinical assessments: localized tenderness at the medial calcaneal tuberosity and a modified version of the Royal London Hospital Test adapted for PF. The study focuses on assessing diagnostic accuracy in terms of sensitivity, specificity, reproducibility, and predictive values in patients presenting with clinical signs consistent with PF. The modified test has not yet undergone formal validation, and this investigation is intended to provide preliminary evidence regarding its clinical applicability.

In addition, the study explores the role of gastrocnemius tightness within the proposed biomechanical framework by assessing the reproducibility and prevalence of the Silfverskiöld test in the same population.

The study adopts a controlled design with blinded assessment by multiple examiners under standardized conditions. Repeated evaluations within the same day are performed to assess intra- and inter-observer reliability. This methodological approach is intended to ensure robustness in the evaluation of diagnostic performance and to minimize measurement bias.

Overall, the study aims to contribute to the development and validation of simple, clinically applicable diagnostic tools for plantar fasciopathy, with potential implications for improving early diagnosis and optimizing patient management.

Inclusion criteria

• PF group:

• Patients on the waiting list at Clinic I of the Rizzoli Orthopaedic Institute for surgical intervention with a diagnosis of recalcitrant PF lasting at least 12 months
• Age >18 years
• MRI of the foot and ankle negative for other local causes of pain included in the differential diagnosis of PF
• Negative electromyography for tarsal tunnel syndrome
• Control group:

• Age >18 years
• Outpatients followed at Clinic I for conditions unrelated to the foot and ankle, with no clinical history of foot pain or pathology in the preceding 12 months

Exclusion criteria

• PF and control groups:

• Minor patients
• Patients with diagnosed rheumatologic diseases currently under pharmacological treatment
• Patients with diabetes or diabetic neuropathy
• Pregnant women