Tenodesis grasp and release is a biomechanical occurrence that allows for some opening and closing of the fingers by movement of the wrist. The tendons of the forearm and fingers cross multiple joints and act as a complex pulley system. When the wrist is extended the tendons along the fingers shorten and pull the finger joints into flexion. Conversely, when the wrist is flexed the tendons along the finger joints lengthen and allow the finger joints to extend passively.
Typically we use our finger flexor and extensor muscles to open and close our fingers and the extension of the wrist allows us to have greater force for pinching and grasping. After a spinal cord injury at the C6 level, a person might be able to send a signal to the muscles controlling the wrist, but not the fingers. We can use the passive mechanical advantage of tenodesis to assist in picking up objects and increase independence in activities such as eating meals and brushing teeth.
TREATMENT FOR AN EFFECTIVE GRASP WITH TENODESIS
SPLINTING AND TAPING
In order for tenodesis to work well, the wrist extensors need to be strengthened and the flexors need to keep tension. It would hinder grasp if the finger extensors were elongated, and positions of full finger extension should be avoided. Splinting and taping can be used to immobilize the finger extensors, which will cause shortening of the tendon into slight flexion to enhance tenodesis function. This should be assessed by an occupational or physical therapist.
RETRAINING THE BRAIN
Our brains are not familiar with using our wrists to open and close the fingers and it takes practice to learn this skill. Mastery comes with repetitions and retraining your brain to achieve a goal in a different way then you originally learned.
STRENGTHENING THE WRIST EXTENSORS
The other key is strengthening the wrist extensors. The finger joints bend and become tighter the more extension is in the wrist. The muscles that control the wrist need to be strengthened through resistance and repetition. Endurance training happens through repetition as well.
Strengthening happens when we fatigue a muscle. Providing resistance at a maximum load for the individual builds muscle, and more repetitions with a lighter load builds endurance. Typically 3 sets of 15 repetitions at which the the 15th repetition is almost impossible to do is the recommended parameters for strength building. Moving the joint against gravity is sometimes enough resistance to build strength, depending on your current strength. If this is easy, you’ll want to increase the level of resistance to continue building strength in a muscle.
USING THE NEOFECT SMARTGLOVE TO DEVELOP TENODESIS GRASP
The NEOFECT Smartglove is a great tool for strengthening the muscles for tenodesis grasp. The Smartglove provides a gamified approach to repetitions of movement for strengthening. Each game targets a specific movement.
Here are ways to build strength and ideas for increasing the level of resistance for each movement, while keeping in mind the focus of building an effective tenodesis grasp.
SUPINATION AND PRONATION GAMES
The movement of the forearm to turn the palm up to the ceiling and down towards the floor is called supination and pronation. Games targeting this movement can be used while holding onto an empty water bottle. Focus on keeping your wrist in slight extension to tighten the grip. This will build stability in the forearm muscles. As your strength builds add water to the bottle to increase the weight and challenge.
WRIST RADIAL AND ULNAR DEVIATION GAMES
Wrist radial deviation is when the hand moves at the wrist joint in the direction of the thumb, and ulnar deviation is when the hand moves at the wrist joint in the direction of the pinkie. The most effective position for this movement is with the wrist in slight extension. If the wrist is flexed, the index finger will extend and should be prevented for tenodesis, as we want to keep the finger flexors shortened, instead of elongated. Holding onto a water bottle or placing a wrist weight around your fingers would also be a good way to incorporate grasp during the games and increase the weight and level of resistance for strengthening.
WRIST FLEXION AND EXTENSION GAMES
Bending the wrist up and down is called wrist flexion and extension. This is the key movement for tenodesis. Consider using a wrist weight around your fingers to provide resistance as you extend your wrist. It will also provide something to “grip” your fingers around.
FINGER FLEXION AND EXTENSION GAMES
The Smartglove uses the finger sensors to track finger flexion and extension. People with spinal cord injury can also play these games by using tenodesis to open and close their fingers. To add resistance, use a stress ball with a light resistance to start off with, then progress to greater resistance. There are hand exercise balls with a loop that can be placed on the middle finger to prevent the ball from falling out of the hand.
For more information about the NEOFECT Smartglove to improve tenodesis grasp or to find out more about our other rehabilitation products, please call (866) 534-4989 or email firstname.lastname@example.org.
Nas, K., Yazmalar, L., Şah, V., Aydın, A., & Öneş, K. (2015). Rehabilitation of spinal cord injuries. World journal of orthopedics, 6(1), 8–16. doi:10.5312/wjo.v6.i1.8
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