What is the difference between the Henry and modified Henry approach for accessing the distal end of the radius?

Henry vs Modified Henry Approach to Distal End Radius: Anatomical Comparison and Surgical Technique

The modified Henry approach offers superior access to the distal radius with less risk to neurovascular structures compared to the traditional Henry approach, particularly for volar plating of distal radius fractures. 1, 2

Traditional Henry Approach

• The volar Henry approach is considered the gold standard for distal radius fracture fixation, allowing for decreased nonunion rates, reduced complex regional pain syndrome (CRPS) incidence, and early wrist mobilization 1
• This approach involves an incision along the line connecting the biceps brachii tendon and the styloid process of radius 2
• The approach proceeds through three phases:
  • First phase: Careful incision to avoid damaging the lateral cutaneous nerve of forearm 2
  • Second phase: Fascia incision with identification of the brachioradialis, with retraction of the superficial branch of the radial nerve laterally and the radial artery medially 2
  • Third phase: Identification of the pronator teres attachment and careful exposure of the proximal radius to avoid damaging the deep branch of the radial nerve 2

Modified Henry Approach

• The modified Henry approach is a mini-invasive technique using a significantly smaller incision (approximately 15-16mm) compared to the traditional approach 1
• This approach maintains the benefits of the volar approach while addressing disadvantages such as the aesthetically displeasing larger incision and loss of ligamentotaxis 1
• Key advantages include:
  • Reduced tissue trauma and improved cosmetic outcomes 1
  • Preservation of the pronator quadratus muscle, which provides plate coverage and a protective gliding layer 3
  • Better reattachment of the pronator quadratus muscle, as the traditional approach often results in incomplete or tenuous repair 3

Anatomical Dissection Comparison

• The traditional Henry approach uses the interval between flexor carpi radialis and the radial artery, involving incision of the radial border of the pronator quadratus 3
• The modified approach (sometimes called "Brachioradialis splitting" approach) utilizes the anatomic relationship between brachioradialis and pronator quadratus to allow simple and stable reattachment of the pronator quadratus muscle 3
• In the modified approach, the brachioradialis is split rather than retracted, providing more direct access while preserving muscle function 3

Specialized Variants for Specific Fracture Patterns

• For fractures involving the volar-ulnar portion (lunate facet) of the distal radius, the traditional Henry approach has limitations in achieving adequate exposure 4
• An anteromedial approach or volar-ulnar approach can provide better access to the medial side of the volar distal radius and the distal radio-ulnar joint 5, 4
• These specialized approaches allow optimal reduction of the sigmoid notch and the volar lunate facet, anatomically reducing both the radiocarpal joint and the sigmoid notch 4

Clinical Outcomes

• Studies show the mini-invasive modified Henry approach is reliable and reproducible with few complications 1
• Clinical outcomes with the modified approach include:
  • Mean Quick DASH score of 25 1
  • Average range of motion more than 85% compared to the contralateral side 1
  • Global force of the hand at 67% compared with contralateral side 1
  • Radiographic outcomes showing mean radial slope of 22°, mean radial tilt of 8.3°, and mean radioulnar variance/index of -0.4 mm 1

Potential Complications and Considerations

• Both approaches carry risk of injury to the deep branch of the radial nerve, though this risk is higher with the traditional approach, especially in the proximal third of the radius 2
• The modified Henry approach reported specific complications including:
  • Nine cases of CRPS type I (all resolved) 1
  • Two secondary displacements 1
  • Nine tenosynovitis cases 1
  • No tendon ruptures were noted 1

Practical Application

• The traditional Henry approach may be used for any fracture of the radial shaft and provides safe exposure of the entire lateral and anterior surfaces of the radius 2
• The modified approach is particularly advantageous for distal radius fractures requiring volar plating 1, 3
• The modified approach can be associated with arthroscopy, scaphoid screw fixation, or percutaneous pinning, allowing treatment of most traumatic lesions of the wrist through this mini-invasive approach 1