Diagnostic Validity Ofclinical Tests for Infrapatellar Fat Pad Impingement Syndrome

NCT06971601 | Recruiting

• 2 other identifiers: ETICHOFFA2024-A02410-47
• Study Type: observational
• Target: 50
• Locations: 1 country
• Sites: 1

Brief Summary

The ETICHOFFA study is a clinical research project aiming to improve the diagnosis of Infrapatellar fat pad impingement syndrome, a common source of anterior knee pain. Although MRI remains the gold standard for diagnosis, clinical testing strategies lack validation. This observational study has two main objectives: to assess the diagnostic accuracy of a cluster of standardized clinical provocation tests for IFP impingement compared to MRI findings, and to identify clinical and subjective characteristics associated with IFP involvement confirmed by imaging. This observational study will recruit 50 patients aged 18 to 70 years with anterior knee pain rated at least 3 out of 10 in intensity. Participants will complete a secure online questionnaire documenting symptoms, pain distribution, aggravating and relieving factors, and pain intensity at rest, during activity, and daily life. They will also complete three validated scales: the Anterior Knee Pain Scale (AKPS), the Knee injury and Osteoarthritis Outcome Score (KOOS), and the Tampa Scale for Kinesiophobia (TSK). A standardized clinical examination will be performed, including subpatellar skin temperature measurement, knee swelling assessment, passive range of motion testing, and a series of provocation tests targeting Hoffa's fat pad. Tests will be randomized to reduce bias and considered positive if they reproduce the patient's typical pain with an intensity of at least 2/10. Each participant must also undergo a standardized MRI of the knee within two weeks of the clinical assessment, interpreted blindly by an independent musculoskeletal radiologist. All data will be anonymized, stored securely, and analyzed using SPSS software. Diagnostic accuracy of clinical tests will be evaluated through sensitivity, specificity, predictive values, and likelihood ratios. Functional outcomes related to taping will also be analyzed. The study has received ethical approval and adheres to GDPR standards for data protection. Participation is voluntary, with the right to withdraw at any time. The ETICHOFFA study is expected to enhance clinical diagnostic pathways for anterior knee pain associated with Infrapatellar fat pad involvement.

Conditions

Anterior Knee Pain

Keywords

Hoffa's fat pad; Infrapatellar fat pad; Diagnosis; MRI

Outcome Measures

Primary Outcomes (1)

• The primary endpoint of this study is the diagnostic value of the five clinical tests targeting the infrapatellar fat pad, considered collectively as a test cluster.

  The overall performance of the test cluster will be analyzed using contingency matrices comparing the combined clinical test results with MRI findings. Various combination strategies will be tested (e.g., ≥2 positive tests out of 5), and the following diagnostic validity indices will be calculated for each threshold: sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and positive and negative likelihood ratios (LR⁺, LR-). ROC curves will be generated, and the area under the curve (AUC) will be used as a synthetic indicator of the cluster's discriminative capacity, with an AUC ≥ 0.80 considered clinically meaningful.

  At baseline (post-imaging and clinical assessment)

Secondary Outcomes (13)

• Diagnostic performance of individual clinical tests

  At baseline (post clinical assessment)

• Post-test probability of Infrapatellar fat pad impingement (Fagan nomogram analysis)

  At baseline (post-imaging and clinical assessment)

• Infrapatellar skin temperature at rest (lying position)

  At baseline (during initial clinical assessment)

• Presence of intra-articular swelling (Stroke Test)

  At baseline (during initial clinical assessment)

• Passive range of motion of the knee (flexion and extension)

  At baseline (during initial clinical assessment)

Interventions

Provocative test DIAGNOSTIC_TEST

The clinical evaluation specific to Infrapatellar fat pad is based on a series of five standardized clinical tests, extensively described in the specialized literature: provoked palpation of the fat pad, provoked passive extension, Hoffa's test, gliding test, and provoked passive flexion. These tests are performed in a randomized order to limit sequence bias. A test is considered positive if it reproduces the patient's typical anterior knee pain with an intensity greater than 2/10 on the numerical pain scale. Although widely used, these tests have not yet undergone rigorous methodological validation, which this study specifically aims to address.

Eligibility Criteria

• Age: 18 Years - 70 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

Adults aged 18 to 70 years experiencing anterior knee pain (AKP) rated ≥3/10 for at least 4 weeks will be eligible. Patients will be recruited from the department of orthopedic and trauma at Hôpital Paris-Est Val de Marne (Saint-Maurice), including both postoperative cases (e.g., post-arthroscopy) and non-surgical patients referred for expert consultation regarding persistent or unexplained anterior knee pain.

You may qualify if:

• Age between 18 and 70 years
• Presence of anterior knee pain with an intensity of ≥3/10 on the Numerical Rating Scale (NRS), on most days over the past month
• MRI of the knee performed within a maximum of 15 days before or after the clinical examination.

You may not qualify if:

• History of corticosteroid injection treatment within the previous 12 months;
• Known allergy or skin intolerance to medical adhesives or rigid tape;
• History of hip or lumbar spine surgery;
• History of neurological disorders or a diagnosis of fibromyalgia;
• Contraindication to MRI (e.g., metallic foreign body, incompatible implantable device)

Sponsors & Collaborators

• Hopitaux de Saint-Maurice: lead

Study Sites (1)

Hôpitaux Paris Est Val-de-Marne - Service de rééducation orthopédique et traumatologie

Saint-Maurice, 94410, France

RECRUITING

MeSH Terms

Conditions

Disease

Condition Hierarchy (Ancestors)

Pathologic Processes; Pathological Conditions, Signs and Symptoms

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: CROSS SECTIONAL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: April 28, 2025
• First Posted: May 14, 2025
• Study Start: June 17, 2025
• Primary Completion: October 28, 2025
• Study Completion (Estimated): June 1, 2026
• Last Updated: February 20, 2026

Record last verified: 2025-05

Locations

FR (1)