Lipedema is a chronic adipose tissue disorder that commonly leads to joint laxity, hypermobility, and functional limitations, yet its impact on foot morphology has not been systematically examined. This case-control study aims to investigate whether patients with lipedema exhibit a higher prevalence of generalized joint hypermobility and foot structural abnormalities-specifically pes planus-compared with age- and BMI-matched controls. Using radiographic measurements (Meary angle and calcaneal inclination angle), clinical hypermobility assessment, and validated functional scales, the study seeks to determine the relationship between lipedema, hypermobility, and foot function.

Lipedema is a progressive adipose tissue disorder characterized by disproportionate subcutaneous fat accumulation, predominantly in the lower extremities. Patients frequently experience pain, easy bruising, reduced quality of life, and musculoskeletal complications such as joint laxity and hypermobility. Although previous studies have suggested an increased prevalence of hypermobility in individuals with lipedema, the potential impact of these biomechanical changes on foot posture and foot function remains insufficiently studied.

This case-control, single-session, single-blind (participant-blinded) study is designed to evaluate structural and functional foot characteristics in women diagnosed with lipedema, compared with age- and BMI-matched controls presenting with nonspecific foot pain. The primary radiographic variables include the Meary angle and calcaneal inclination angle measured on standardized lateral foot radiographs. These measurements provide objective quantification of midfoot alignment and arch height, enabling detection of pes planus and related morphological deviations.

In addition to radiographic assessment, the study incorporates established clinical tools to quantify joint hypermobility, foot function, pain severity, and physical activity levels. The Beighton score will be used to determine generalized joint hypermobility. Functional and symptomatic status will be evaluated using validated questionnaires, including the Foot Function Index (FFI), Lower Extremity Functional Scale (LEFS), Visual Analog Scale (VAS) for pain, and the International Physical Activity Questionnaire-Short Form (IPAQ-SF).

Sociodemographic and clinical data-including disease duration, comorbidities, and lower extremity volumetric measurements-will be systematically recorded to identify potential associations between patient characteristics and foot morphology. The study aims to clarify whether the presence of hypermobility in lipedema contributes to alterations in medial longitudinal arch structure and whether these changes are more prevalent than in a matched control population.

The findings are expected to provide insight into the biomechanical consequences of lipedema, support more accurate clinical assessment, and potentially guide rehabilitative strategies targeting lower extremity alignment and function in this patient group.

General Inclusion Criteria (Apply to All Participants)

• Female participants
• Age 18 years or older
• Able to read and write (literacy requirement)
• Availability of bilateral lateral foot radiographs obtained within the past 1 year in the hospital PACS system
• Willing and able to provide written and verbal informed consent

Additional eligibility criteria for Lipedema Group

- Clinical diagnosis of lipedema according to Halk and Damstra criteria.

Additional eligibility criteria for Control group:

• Female patients presenting with nonspecific foot pain
• Similar age and BMI range as the lipedema group
• No clinical diagnosis or suspicion of lipedema

Exclusion Criteria (Apply to all participants)

• Pregnancy
• Illiteracy
• Inability or unwillingness to provide written and verbal informed consent
• History of lower extremity fracture, trauma, or orthopedic surgery
• Diagnosis of diabetes mellitus
• Known rheumatologic disease
• Known polyneuropathy or peripheral nerve injury affecting the lower extremities

Female patients presenting to the Physical Medicine and Rehabilitation outpatient clinics at Marmara University Pendik Training and Research Hospital will be screened for eligibility. The study population will include women clinically diagnosed with lipedema according to established diagnostic criteria, as well as age- and BMI-matched female patients with nonspecific foot pain who will serve as the control group.

IPD and supporting documents will be available 6 months after publication of the main results and remain accessible for at least 5 years following publication.

Qualified researchers may request access to the de-identified dataset and supporting documentation by submitting a brief research proposal and data access agreement to the corresponding investigator (Gökçenur Yalçın, M.D., Department of Physical Medicine and Rehabilitation, Marmara University, Istanbul, Turkey). Data will be shared via a secure institutional data repository upon approval by the principal investigator and the Marmara University Ethics Committee.