Conventional and Virtual Reality-Based Neuromuscular Rehabilitation in Scapholunate Instability

Electromyographic and Functional Analysis of Neuromuscular Rehabilitation Methods in Individuals With Scapholunate Instability: A Comparison of Conventional and Virtual Reality-Supported Interventions

Scapholunate instability is a common form of carpal instability that can cause wrist pain, weakness, and functional limitations during daily activities. Conservative rehabilitation approaches are frequently recommended in the early stages; however, there is no standardized rehabilitation protocol, and the effects of different neuromuscular rehabilitation methods have not been sufficiently investigated.

The primary aim of this study is to comparatively examine the effects of conventional physiotherapy approaches and virtual reality-supported neuromuscular rehabilitation on forearm muscle activation patterns assessed using surface electromyography, wrist proprioceptive function (joint position sense), pain intensity, and functional improvement in individuals with scapholunate instability, and to identify clinically applicable rehabilitation protocol approaches for this population.

In this single-blind randomized controlled trial, participants with pre-dynamic or dynamic scapholunate instability will be randomly assigned to either a conventional rehabilitation group or a virtual reality-supported rehabilitation group. Both groups will receive an 8-week rehabilitation program administered twice per week. Primary outcome measures will include electromyographically assessed forearm muscle activation and wrist proprioception. Secondary outcome measures will include pain intensity, grip strength, wrist muscle strength, and upper extremity functional outcomes assessed using validated clinical instruments. All outcome assessments will be performed before and after the intervention period by an assessor blinded to group allocation.

Scapholunate instability is the most common form of carpal instability and is characterized by disruption of the scapholunate interosseous ligament, leading to altered wrist kinematics, pain, reduced grip strength, proprioceptive deficits, and functional limitations. In the early (pre-dynamic and dynamic) stages of the condition, conservative management is recommended; however, standardized, evidence-based rehabilitation protocols are lacking. In particular, the neuromuscular mechanisms underlying wrist stabilization, muscle activation patterns, and proprioceptive control have not been sufficiently investigated using objective measurement methods.

This randomized, single-blinded controlled trial is designed to compare the effects of conventional physiotherapy and virtual reality-supported neuromuscular rehabilitation in individuals with scapholunate instability. Participants diagnosed with pre-dynamic or dynamic scapholunate instability will be randomly allocated to either a conventional rehabilitation group or a virtual reality-supported rehabilitation group. Both groups will receive an 8-week intervention program consisting of two supervised sessions per week. The conventional rehabilitation program will focus on strengthening "scapholunate-friendly" wrist and forearm muscles, improving neuromuscular control, and enhancing wrist proprioception through progressive strengthening and proprioceptive exercises. The intervention group will receive the same conventional program supplemented with virtual reality-based rehabilitation games designed to promote task-oriented movement, sensorimotor integration, and real-time feedback.

Outcome assessments will be conducted before and after the intervention by a blinded evaluator. Primary outcome measures will include wrist proprioception (joint position sense) and forearm muscle activation patterns assessed using surface electromyography. Secondary outcome measures will include pain intensity, grip strength, wrist muscle strength, pressure pain threshold, and upper extremity functional performance assessed using validated clinical outcome measures.

The study aims to objectively evaluate neuromuscular and proprioceptive changes associated with different rehabilitation approaches and to determine whether virtual reality-supported rehabilitation provides additional benefits over conventional physiotherapy alone. The findings of this study are expected to contribute to the development of clinically applicable, evidence-based rehabilitation protocols for individuals with scapholunate instability and to provide insight into muscle activation strategies involved in wrist stabilization.

Inclusion Criteria:

• Aged between 18 and 65 years
• Diagnosed with scapholunate instability (pre-dynamic or dynamic instability) by a physician and referred for conservative treatment
• A score of ≤6 on the Beighton Hypermobility Scale
• Presence of clinical instability symptoms, including pain, a sense of instability, and functional limitation
• Willingness to participate in the study and high motivation to comply with the intervention protocol

Exclusion Criteria:

• History of previous surgery involving the hand or wrist
• Presence of any neurological or cardiovascular disorder
• Presence of additional orthopedic pathology affecting the shoulder, elbow, or wrist other than scapholunate instability
• History of surgery involving the ipsilateral upper extremity within the past 6 months
• Presence of visual or hearing impairments that may interfere with participation in the rehabilitation program
• Participation in sensory- or function-oriented rehabilitation of either hand within the past 6 months
• A score below 26 on the Montreal Cognitive Assessment (MoCA)
• Inability to read or write