The Missing Dimension: Why Bidirectional Evaluation could be a Predictor of Hand Health

Hand strength has served as a cornerstone of clinical assessment over decades. Recognized as a reliable indicator of overall muscle function, physical performance, and nutritional status, the handgrip test is a staple in orthopedic, rehabilitation, and geriatric practice ^[1,2]. It is frequently utilized as an objective outcome measure due to its simplicity and significant prognostic value for functional independence and the diagnosis of sarcopenia ^[3,4,5]. Yet, despite its ubiquity, our current approach remains surprisingly one-sided. By focusing almost exclusively on the force generated during hand closure, clinical practice has largely overlooked the critical role of the extensor muscles responsible for hand opening ^[2,3].

Beyond the Squeeze: Limitations of Traditional Assessment

Although the conventional hydraulic and digital hand dynamometers are very reliable and valid, only flexor muscle strength can be quantified during a grip ^[2,3,4,5,6]. This focus does not give an objective assessment of the function of the extensor muscles, which is necessary for controlled opening of the hand, release of the object and dexterity ^[3].

This gap may consequently lead clinicians relying on standard unidirectional instruments to ignore objective extensor weakness assessment or major muscle imbalances despite a patient achieving a seemingly “normal” grip strength score ^[3,6]. This constraint is particularly relevant for specific populations, including individuals recuperating from:

Orthopedic injuries: Tendon repairs, fractures, and reconstructive hand surgeries where balanced muscle function is critical ^[2,3].

• Orthopedic injuries: Tendon repairs, fractures, and reconstructive hand surgeries where balanced muscle function is critical ^[2,3].

• Neurological conditions: Patients with stroke or peripheral nerve disorders who require nuanced neuromuscular recovery data.

• Sports medicine: Athletes needing coordinated grip-and-release patterns for high-level performance ^[4,7].

The Bidirectional Advantage

Normal hand function requires coordinated flexor and extensor muscle activity, and functional performance cannot be fully understood by looking at one without the other ^[4]. Bidirectional evaluation quantifies the grip and the opening force and provides a more comprehensive understanding of muscle balance and rehabilitation progress. The approach is in line with the current evidence-based treatment guidelines regarding functional goals rather than isolated strength measurements ^[8,9].

Innovation in Measurement

The Bidirectional Grip Strength Measuring Medical Device ^[10] was created to address this clinical requirement. The innovation is unique in that it measures two separate grip strengths (flexor and extensor strength) without the need to have two devices. With configurable bidirectional resistance and real-time force feedback, the device provides a useful and portable instrument for performing thorough hand examinations in a variety of clinical scenarios.

The Path Forward

Evaluations of functional outcomes and return to work may be enhanced by combining assessments in both directions of flexion and extension ^[2,6]. Extensive work in establishing normative hand opening and closing reference values could serve as target points to be achieved across demographics ^[2,7,8]. It would help clinicians to select treatment approaches in line with our understanding of “recovery” as the restoration of a balanced and coordinated functioning that would allow them to have a good quality of life.

References

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About the Authors

• 

  Sagar Deshpande

• 

  Sachin Kale

• 

  Mugdha Oberoi

• 

  Ashok Shayam