In vivo flexor tendon forces generated during different rehabilitation exercises

Area of Science:

• Orthopedic Surgery
• Rehabilitation Medicine
• Biomechanics

Background:

• Flexor tendon repair requires careful rehabilitation to ensure healing and prevent re-injury.
• Understanding the in vivo forces generated during different rehabilitation exercises is crucial for optimizing patient recovery.

Purpose of the Study:

• To measure the in vivo forces in the flexor digitorum profundus (FDP) and flexor digitorum superficialis (FDS) tendons during common post-operative rehabilitation maneuvers.
• To compare these measured forces with the reported strength of flexor tendon repairs to guide safe rehabilitation protocols.

Main Methods:

• Buckle force transducers were placed on the FDP and FDS tendons of the index finger in 12 patients undergoing open carpal tunnel release.
• In vivo forces were measured during various rehabilitation maneuvers, including isolated FDP/FDS flexion, active finger flexion, and place and hold exercises, with varying wrist positions.

Main Results:

• Isolated FDP flexion (24 N) and isolated FDS flexion (13 N) generated significantly higher forces than other maneuvers.
• Wrist flexion to 30° increased FDS forces (6 N vs. 5 N in neutral).
• Active finger flexion (6 N) generated higher FDP forces than place and hold (3 N). Place and hold, active flexion with a neutral wrist, and tenodesis produced the lowest forces.

Conclusions:

• Rehabilitation maneuvers involving isolated flexion of the FDP or FDS tendons generate forces that may exceed the repair strength.
• Gentler exercises, such as place and hold or active flexion with a neutral wrist, are recommended to minimize stress on repaired flexor tendons.