Functional Muscle-Bone Incongruity Index (FKUI): A Prospective Observational Study

This is a prospective, observational, single-center study evaluating adults undergoing routine DXA assessment in a Physical Medicine and Rehabilitation outpatient clinic. The study will investigate the clinical applicability of the Functional Muscle-Bone Incongruity Index (FKUI), a composite approach based on handgrip strength, total hip bone mineral density, and lumbar-hip bone mineral density discordance. No treatment or interventional procedure will be administered as part of the study. Handgrip strength will be measured using a calibrated hand dynamometer, and DXA-derived bone mineral density values will be recorded from routine clinical assessments. The study aims to determine whether the combined evaluation of muscle function and bone health parameters may provide a more comprehensive assessment of musculoskeletal status.

Inclusion criteria

• Age 18 years or older
• Attendance at the Physical Medicine and Rehabilitation outpatient clinic
• Scheduled to undergo routine bone mineral density assessment by DXA as part of clinical evaluation
• Ability to perform handgrip strength testing
• Availability of lumbar spine and total hip bone mineral density measurements suitable for analysis
• Ability and willingness to provide written informed consent

Exclusion criteria

Exclusion criteria

• Age younger than 18 years
• Secondary causes of osteoporosis (e.g., hyperparathyroidism, Cushing syndrome, malignancy, or other conditions affecting bone metabolism)
• History of metabolic bone disease
• Major trauma or fracture within the previous 6 months
• Upper extremity disorders that may significantly affect handgrip strength measurement (e.g., severe osteoarthritis, neurological disorders, major deformities)
• DXA measurements that are technically inadequate or unsuitable for analysis
• Refusal or inability to provide written informed consent