Active extensor indicis proprius extension strength after its use as a tendon transfer: 19 cases

Area of Science:

• Orthopedic surgery
• Hand surgery
• Reconstructive surgery

Background:

• Complications of extensor indicis proprius (EIP) tendon transfer can include loss of index finger extension strength, independence, and mobility.
• Assessing the functional outcomes of EIP tendon transfer is crucial for patient recovery and surgical decision-making.

Purpose of the Study:

• To quantitatively measure independent and dependent index finger extension strength after EIP tendon transfer.
• To evaluate the retention of independent index finger extension and second metacarpophalangeal (MCP) joint mobility post-transfer.
• To determine the functional impact of EIP tendon harvesting on daily activities.

Main Methods:

• Nineteen patients undergoing EIP tendon transfer were studied.
• EIP tendon was divided proximally and rerouted to a recipient tendon.
• Independent and dependent extension strength, independent active extension, and MCP joint mobility were assessed at an average 41-month follow-up.

Main Results:

• Average independent extension strength decreased from 11N (contralateral) to 5.6N (operated).
• Average dependent extension strength decreased from 20N (contralateral) to 10.9N (operated).
• All patients maintained independent active extension; however, a 15.3° extension lag was noted in the second MCP joint.

Conclusions:

• EIP tendon transfer results in reduced independent and dependent strength and active extension of the second MCP joint.
• Despite measurable strength deficits, the functional impact on patients was negligible.
• The extensor indicis proprius tendon remains a viable option for tendon transfer procedures.