Joint Hyperlaxity and Volar Plate Dynamics: MRI-Based Comparative Evaluation of the PIP Joint

N/ACompletedNCT07082075

Hacettepe University32 enrolled

Overview

Background: The volar plate (VP) is a key stabilizer of the proximal interphalangeal joint (PIPJ), and its biomechanical behavior may be altered in individuals with joint hypermobility. Objective: This study aimed to evaluate the spatial dynamics of the VP and its relationship with the center of joint motion and flexor digitorum profundus (FDP) tendon in individuals with and without joint hyperlaxity using MRI. Methods: Thirty-two healthy volunteers (16 hyperlax, 16 controls) underwent MRI imaging of both index fingers at five flexion angles (0°, 30°, 60°, 90°, full flexion) and under passive and isometric loading conditions. Key parameters measured included distances from the joint center to VP attachments, VP-FDP tendon distance, and the length between VP ends.

Study Type

OBSERVATIONAL

Enrollment

Conditions

Hypermobility, Joint

Eligibility

Sex: ALLMin age: 18 YearsMax age: 65 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * between 18-65 years Exclusion Criteria: * any history of acute or overuse injuries to the examined hand, * any prior surgical procedures on the examined upper extremity.

Locations (1)

Hacettepe University

Ankara, Ankara, Turkey (Türkiye)

Outcomes

Primary Outcomes

The Distance Between the Center of Motion (CoM) and the VPLip and VPTip

The distances between the center of motion (CoM) and the volar lip of the middle phalanx base (VPLip), and between the CoM and the proximal end of the volar plate at its attachment to the volar base of the proximal phalanx (VPTip), were measured using RadiAnt DICOM Viewer software (version 2024.1) in various PIPJ angles.

Time frame: baseline

The Distance Between VPLip and VPTip

The distance between the volar lip of the middle phalanx base (VPLip), and the proximal end of the volar plate at its attachment to the volar base of the proximal phalanx (VPTip) measured using RadiAnt DICOM Viewer software (version 2024.1) in various PIPJ angles. The purpose of this measurement was to observe how the distance between the two ends of the volar plate changes with varying joint angles.

Time frame: baseline

The Distance Between Volar Plate (VP) and FDP Tendon

The distance between the midpoint of the volar plate (VP) and the flexor digitorum profundus (FDP) tendon was measured using RadiAnt DICOM Viewer software (version 2024.1) at various proximal interphalangeal joint (PIPJ) angles. The purpose of this measurement was to observe how this distance changes across different flexion angles.

Time frame: baseline

Changes Observed During Grasping and Isometric Contraction

Measurements at all flexion angles were conducted under two conditions: while passively grasping a cylindrical object (without force) and during isometric contraction (with force).

Time frame: baseline