Clinical Decision-Making in FAIS (CDM-FAIS)

Optimizing Treatment Pathway and Clinical Desicion-making in Young Adults With Femoroacetabular Impingement Syndrome

Femoroacetabular impingement syndrome is increasingly recognized as a contributor to cartilage injury and early hip osteoarthritis. Both structured conservative care and arthroscopic surgery can improve pain and function, but a major unresolved clinical problem is deciding who should continue conservative care and who should escalate to surgery, and when. Evidence indicates that shorter symptom duration before surgery is associated with better long-term improvement, meaning delays may reduce the chance of achieving meaningful recovery. Current decision-making still depends largely on static imaging and passive clinical examination, which do not capture the dynamic, movement-related nature of the condition, while advanced three-dimensional imaging and laboratory motion analysis are not practical for routine clinical monitoring. This study aims to address this gap by developing and validating feasible, clinic-ready dynamic assessment methods and integrating weight-bearing pelvic and spinal alignment with three-dimensional hip modeling to support more objective, individualized, and timely treatment decisions.

Study Overview

• Status: Not yet recruiting
• Conditions: Femoracetabular Impingement
• Intervention / Treatment: Diagnostic test: Functional lateral x-ray scans; Diagnostic test: Multi-echo Fast Field Echo (mFFE) MRI; Diagnostic test: Markerless 3D motion capture; Diagnostic test: Marker-based 3D motion capture (optional)

Detailed Description

The escalating socioeconomic burden of hip osteoarthritis has driven a strategic shift toward earlier, joint-preserving interventions. Over the past two decades, femoroacetabular impingement syndrome (FAIS) has been increasingly recognized as a key contributor to cartilage injury and the development of early osteoarthritis. This recognition has not only led to the wider adoption of surgical interventions but also fueled significant advances in arthroscopic management. Yet, despite these developments, a central clinical challenge remains: determining which patients will benefit from prolonged conservative care and which require timely surgical care to optimize outcomes. Indeed, several randomized controlled trials have compared arthroscopy with conservative treatment, consistently showing that both approaches improve pain and function. Arthroscopy has demonstrated reliable short- to mid-term gains in patient-reported outcomes, while rehabilitation and conservative management also enable a substantial proportion of patients to achieve meaningful improvement. Although, these findings highlight the value of both strategies, the optimal sequence and timing of non-surgical and surgical care remains unknown.

Emerging literature makes it clear that the timing of surgical intervention is a critical factor in hip preservation. A recent multi-level systematic review showed that shorter symptom duration before arthroscopy is consistently associated with superior outcomes, including greater functional gains, higher rates of achieving clinically meaningful thresholds, and a lower risk of persistent pain. Similarly, a 10-year longitudinal study demonstrated that durable improvements are most likely when surgery is performed earlier in the disease course, whereas delays reduce the likelihood of achieving Minimal Clinically Important Difference (MCID) and Patient Acceptable Symptom State (PASS) thresholds.

Together, these findings establish timing as a critical determinant of long-term outcomes and underscore the pressing need for dynamic, clinic-ready tools that can guide the transition from rehabilitation to surgery in young adults with FAIS.

However, current diagnosis and treatment planning for FAIS relies heavily on static imaging and passive clinical examination, which cannot capture the dynamic, movement-related nature of the condition. Advanced biomechanical studies have shown that patients with FAIS differ from controls not only in femoral and spinopelvic morphology[8] but also in movement strategies during hip-hinging tasks such as deep squats. While these insights have enhanced our understanding of FAIS, their clinical translation remains very limited due to ethical and practical limitations. Firstly, while CT-based 3D imaging can provide detailed morphological assessment, its relatively high radiation dose makes it unsuitable for repeated monitoring in young adults. Similarly, 3D motion analysis has demonstrated important alterations in kinematics, yet the cost, time demands, and need for technical expertise restrict its use to research laboratories. As a result, there are still no feasible, clinic-ready protocols that adequately capture the dynamic nature of FAIS for everyday decision-making. Consequently, treatment planning in young adults, including the above combination of non-surgical and surgical care, often depends on subjective judgment and limited examination factors, which increases the risk of suboptimal care.

The central challenge, therefore, is not whether FAIS should be managed conservatively or surgically, but how to effectively determine which patients are best suited for each pathway and at what point in their care. As hip preservation moves toward preventive strategies and increasingly refined arthroscopic techniques, developing practical, individualized and objective tools to support timely decision-making is essential. This project aims to directly address that need.

• Study Type: Interventional
• Enrollment (Estimated): 60
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Anna Tarasiuk; Phone Number: +32 16 33 88 18; Email: orthopedie.research@uzleuven.be
• Study Contact Backup: Name: Stijn Ghijselings, Dr.; Phone Number: +32 16 33 88 72; Email: stijn.ghijselings@uzleuven.be

Study Locations

• Belgium
  • Vlaams-Brabant
    • Leuven, Vlaams-Brabant, Belgium, 3000
      • Universitaire Ziekenhuizen KU Leuven
      • Contact: Anna Tarasiuk; Phone Number: +32 16 33 88 18; Email: orthopedie.research@uzleuven.be
      • Contact: Stijn Ghijselings, Dr.; Phone Number: +32 16 33 88 72; Email: stijn.ghijselings@uzleuven.be
      • Principal Investigator: Stijn Ghijselings, Dr.

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Voluntary written informed consent of the participant or their legally authorized representative has been obtained prior to any screening procedures
2. Male or Female, Age 18-35 years inclusive.
3. First consultation at participating site with clinical diagnosis of FAIS by a hip orthopaedic surgeon, including positive impingement tests and reduced hip ROM in the transverse plane compatible with FAIS.
4. Radiographic cam and/or pincer morphology on standard imaging (e.g. α-angle >60°, lateral center-edge angle >40°, crossover sign) as per local protocol.
5. Willingness and ability to participate rehabilitation and complete the recommended physiotherapy sessions and attend scheduled follow-up visits.
6. Ability to perform basic squat / hip-hinge tasks safely in the motion lab, as judged by the treating clinician.

Exclusion Criteria:

1. Previous surgery on the bilareral hip.
2. History of major hip trauma or pediatric hip disease (e.g. Slipped capital femoral epiphysis, Perthes disease).
3. Developmental dysplasia (lateral center-edge ≤20°) or other severe structural deformity incompatible with the standard FAIS pathway.
4. Radiographic signs of hip degeneration (Tönnis grade >2).
5. Other musculoskeletal conditions that significantly interfere with assessments (e.g. symptomatic lumbar disc disease, severe knee pathology, recent adductor muscle pathology).
6. Contraindications to MRI (e.g. non-MRI compatible pacemaker or implant, severe claustrophobia not manageable with standard care).
7. Contraindications to X-ray or MRI related to pregnancy: known pregnancy at any time, or positive pregnancy test prior to imaging; breastfeeding women will not undergo additional research imaging.
8. Inability to perform basic squat/hip-hinge tasks safely (e.g. due to balance, pain or cardiopulmonary limitations).

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Other: Responder to conservative treatment; After 4 months of conservative treatment patients come to a follow-up consultation for clinical re-assessment with the respective treating orthopaedic surgeon to review symptoms progress and treatment plan. Based on clinical reassessment and PROMS results participants will be divided into Responder or Non-responder to conservative treatment based on iHOT-33 change and PASS. Responders: continuation of nonoperative care (8-10 sessions).	Diagnostic test: Functional lateral x-ray scans; Functional lateral x-ray scans will be obtained in three postures: standing, relaxed sitting, and deep flexed sitting. This previously validated protocol, provides posture-specific measures of spinopelvic alignment under physiological load and allows to integrate weight-bearing spinopelvic alignment into 3D hip coverage analysis. By extending imaging beyond a femur-centric perspective, this method better reflects the dynamic, multi-regional nature of FAIS.; Diagnostic test: Multi-echo Fast Field Echo (mFFE) MRI; A multi-echo Fast Field Echo (mFFE) MRI will be acquired to generate highcontrast, bone-like images without ionizing radiation. The imaging sequence can be readily implemented on standard 1.5T and 3T MRI scanners available at the collaborating sites. An in-house pipeline will enable automated 3D segmentation of the lumbar spine, pelvis, acetabulum, proximal femur and condyles.; Diagnostic test: Markerless 3D motion capture; Participants will complete markerless 3D motion capture during three hip-hinge tasks: deep squat, sumo squat, and Romanian deadlift (20% body weight). Lumbar, pelvic and hip movements will be measured in all three planes. Data will be recorded using two research-dedicated iPads running the movement tracking software.; Diagnostic test: Marker-based 3D motion capture (optional); In a subgroup of participants, during three hip-hinge tasks: deep squat, sumo squat, and Romanian deadlift (20% body weight). Lumbar, pelvic, and hip movements will be measured in all three planes using our validated marker-based 3D motion capture system.
Other: Non-responder to conservative treatment; After 4 months of conservative treatment patients come to a follow-up consultation for clinical re-assessment with the respective treating orthopaedic surgeon to review symptoms progress and treatment plan. Based on clinical reassessment and PROMS results participants will be divided into Responder or Non-responder to conservative treatment based on iHOT-33 change and PASS. Non-responders: offered surgery (arthroscopic or mini-open), with full discussion of risks and benefits according to routine practice.	Diagnostic test: Functional lateral x-ray scans; Functional lateral x-ray scans will be obtained in three postures: standing, relaxed sitting, and deep flexed sitting. This previously validated protocol, provides posture-specific measures of spinopelvic alignment under physiological load and allows to integrate weight-bearing spinopelvic alignment into 3D hip coverage analysis. By extending imaging beyond a femur-centric perspective, this method better reflects the dynamic, multi-regional nature of FAIS.; Diagnostic test: Multi-echo Fast Field Echo (mFFE) MRI; A multi-echo Fast Field Echo (mFFE) MRI will be acquired to generate highcontrast, bone-like images without ionizing radiation. The imaging sequence can be readily implemented on standard 1.5T and 3T MRI scanners available at the collaborating sites. An in-house pipeline will enable automated 3D segmentation of the lumbar spine, pelvis, acetabulum, proximal femur and condyles.; Diagnostic test: Markerless 3D motion capture; Participants will complete markerless 3D motion capture during three hip-hinge tasks: deep squat, sumo squat, and Romanian deadlift (20% body weight). Lumbar, pelvic and hip movements will be measured in all three planes. Data will be recorded using two research-dedicated iPads running the movement tracking software.; Diagnostic test: Marker-based 3D motion capture (optional); In a subgroup of participants, during three hip-hinge tasks: deep squat, sumo squat, and Romanian deadlift (20% body weight). Lumbar, pelvic, and hip movements will be measured in all three planes using our validated marker-based 3D motion capture system.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in International Hip Outcome Tool-33 (iHOT-33)	The iHOT-33 questionnaire is a patient-reported questionnaire designed to measure the health-related quality of life in young, active patients with symptomatic hip disease. The questionnaire consists of 33 items divided into four main domains: 1. Symptoms and Functional Limitations; 2. Sports and Recreational Activities; 3. Job-Related Concerns; 4. Social, Emotional, and Lifestyle Concerns. The final score of this questionnaire ranges from 0 to 100, where 100 represents a perfect quality of life with no hip-related limitations, while 0 represents the highest level of disability.	From enrollment to the end of the study, following a 12-month follow-up period

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes in International Physical Activity Questionnaire (IPAQ)	The IPAQ (International Physical Activity Questionnaire) is a standardized tool used to estimate an individual's total physical activity and energy expenditure. The questionnaire asks you to recall your physical activity over the last 7 days. Based on the total score, individuals are categorized into three levels: 1.Low: Not meeting the criteria for the other categories (inactive). 2. Moderate: Roughly equivalent to 30 minutes of at least moderate-intensity activity on most days.3. High: Equivalent to about one hour of activity per day (or very high-intensity training).	From enrollment to the end of the study, following a 12-month follow-up period
Change in Pain Catastrophizing Scale (PCS)	The PCS (Pain Catastrophizing Scale) is a tool designed to measure how a person thinks and feels about their pain. It consists of 13 statements describing different thoughts and feelings. Patients rate how much they experience these thoughts on a 5-point scale, from 0 (Not at all) to 4 (All the time). Patients with high PCS scores often experience higher pain intensity.	From enrollment to the end of the study, following a 12-month follow-up period
Change in Tampa Scale for Kinesiophobia (TSK)	The Tampa Scale for Kinesiophobia (TSK) is a questionnaire used to measure a patient's fear of movement (kinesiophobia). The questionnaire consists of 17 items rated on a 4-point scale (from "Strongly Disagree" to "Strongly Agree"). Scores range from 17 to 68. A score of 37 or higher is generally considered "high," indicating that the person has significant fear that is likely interfering with their recovery.	From enrollment to the end of the study, following a 12-month follow-up period

Collaborators and Investigators

• Sponsor: Universitaire Ziekenhuizen KU Leuven
• Investigators: Principal Investigator: Stijn Ghijselings, Dr., Universitaire Ziekenhuizen KU Leuven

Study record dates

Study Major Dates

• Study Start (Estimated): July 1, 2026
• Primary Completion (Estimated): July 1, 2029
• Study Completion (Estimated): July 1, 2029

Study Registration Dates

• First Submitted: April 10, 2026
• First Submitted That Met QC Criteria: April 10, 2026
• First Posted (Actual): April 17, 2026

Study Record Updates

• Last Update Posted (Actual): May 6, 2026
• Last Update Submitted That Met QC Criteria: May 5, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: FAIS
• Additional Relevant MeSH Terms: Musculoskeletal Diseases; Pathologic Processes; Joint Diseases; Pathological Conditions, Signs and Symptoms; Femoracetabular Impingement; Diagnostic Techniques and Procedures; Diagnosis; Tomography; Diagnostic Imaging; Magnetic Resonance Imaging
• Other Study ID Numbers: S71997

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No