Is tendon transfer surgery for a chronic Z deformity of the thumb due to rupture of the extensor pollicis brevis (EPB) tendon considered a functional reconstructive procedure rather than a cosmetic one?

Tendon Transfer Surgery for Chronic Z Deformity of the Thumb is a Functional Reconstructive Procedure

Tendon transfer surgery for a chronic Z deformity of the thumb due to rupture of the extensor pollicis brevis tendon is definitively a functional reconstructive procedure rather than a cosmetic one, as it restores essential thumb function and improves quality of life. 1

Functional Basis for Tendon Transfer Surgery

• Tendon transfer surgery for chronic thumb deformities aims to restore critical thumb functions including extension, opposition, and pinch strength, which are fundamental to hand function and daily activities 2
• Similar to how strabismus surgery is considered functional (not cosmetic) because it eliminates diplopia, thumb tendon transfer surgery is functional because it restores essential hand capabilities 1
• Long-term follow-up studies demonstrate that tendon transfer procedures for thumb extension restoration result in significant functional improvements, with patients regaining up to 95% of grip strength and 92% of pinch strength compared to the unaffected side 2

Functional Outcomes of Tendon Transfer Surgery

• Tendon transfer procedures for chronic extensor tendon ruptures result in total active motion averaging 89-93% of the normal contralateral side, representing substantial functional improvement 3, 4
• Following tendon transfer surgery, 97% of patients are able to return to their previous employment, demonstrating the procedure's significant impact on functional capacity and quality of life 3
• The functional nature of these procedures is further evidenced by improvements in standardized outcome measures such as the Quick Disabilities of the Arm, Shoulder and Hand score, which measures functional ability 4

Surgical Approaches and Their Functional Benefits

• Multiple surgical techniques exist for addressing chronic extensor pollicis brevis ruptures, including:

  • Transfer of the extensor carpi radialis brevis tendon 2
  • L-lengthening local tendon flap techniques 3
  • Partial extensor carpi radialis longus tendon grafting 4
  • Dynamic loop suture techniques 5

• Each of these approaches is specifically designed to restore functional thumb extension, not merely improve appearance 2, 3, 4, 5

Clinical Considerations

• Chronic Z deformity of the thumb significantly impairs hand function by compromising:

  • Thumb extension capability
  • Precision grip
  • Power grip
  • Fine motor control
  • Overall hand dexterity 2, 4

• Without surgical intervention, patients experience ongoing functional limitations that affect activities of daily living, work capacity, and quality of life 3

• The American Academy of Orthopaedic Surgeons recognizes tendon repair and transfer procedures as functional reconstructive procedures aimed at restoring motion and strength 6

Potential Complications and Considerations

• While generally successful, tendon transfer procedures may have complications including:

  • Mild metacarpal-phalangeal joint stiffness, particularly in chronic cases 5
  • Rare need for revision surgery due to tendon adhesions (approximately 3% of cases) 3
  • Potential compromise of donor site function, which must be balanced against the functional gain in the thumb 4

• Early rehabilitation is crucial for optimizing functional outcomes when no other associated injuries exist 5