What is the importance of the watershed area at the distal end of a radius fracture?

From the Guidelines

The watershed area at the distal end of the radius is a critical factor in the management of distal radius fractures, as it is a vulnerable zone with limited blood supply that can compromise healing if disrupted. This area, located approximately 2-3 cm proximal to the radiocarpal joint, marks the junction between the dorsal and volar blood supplies to the radius, and its importance is highlighted in the American Academy of Orthopaedic Surgeons (AAOS) and American Society for Surgery of the Hand (ASSH) clinical practice guideline summary on the management of distal radius fractures 1. When a distal radius fracture occurs, disruption of this watershed area can compromise healing due to its tenuous vascularity, and surgeons must be particularly careful when placing hardware in this region during fracture fixation, as excessive periosteal stripping can further compromise blood flow and lead to avascular necrosis or delayed union.

Key considerations for surgical planning include:

• Avoiding positioning volar locking plates directly over the watershed area when possible
• Minimizing soft tissue disruption to preserve blood flow
• Understanding the anatomical vulnerability of the watershed area to explain why some distal radius fractures may heal more slowly or develop complications despite appropriate treatment The AAOS and ASSH guideline, which involved reviewing over 7,100 abstracts and more than 830 full-text articles, provides evidence-based recommendations for the treatment of distal radius fractures, including the importance of considering the watershed area in surgical planning 1. By prioritizing the preservation of blood flow to the watershed area, surgeons can optimize outcomes and reduce the risk of complications in patients with distal radius fractures.

From the Research

Importance of Watershed Area at Distal End Radius Fracture

• The watershed area at the distal end of the radius is crucial in the management of distal radius fractures, as it can affect the outcome of the treatment 2, 3.
• The studies suggest that the treatment of distal radius fractures should aim to restore the anatomy of the wrist, including the radial length and the articular surface, to achieve optimal functional outcomes 2, 4.
• The choice of treatment, whether operative or non-operative, depends on the stability and displacement of the fracture, as well as the presence of any associated injuries 3, 5.
• The use of internal fixation, such as plate fixation, can provide better restoration of radial length and reduced infection rates compared to external fixation 2.
• However, the long-term outcomes of open reduction internal fixation versus external fixation of distal radius fractures show no significant difference in most outcomes, although flexion/extension arcs were significantly improved in the ORIF group 4.

Treatment Options

• Non-operative conservative management is generally employed for stable non-displaced fractures of the distal radius, with the expectation of a good functional outcome 3, 6.
• Unstable comminuted fractures with intra-articular and extra-articular fragment zones may require operative management, such as osteosynthesis or external fixation 3, 5.
• Palmar locked plate osteosynthesis has been established as the gold standard for operative management of distal radius fractures 3.

Complications and Outcomes

• The complications of distal radius fractures can include infection, nerve damage, and stiffness, among others 2, 4.
• The outcomes of treatment can be affected by the accuracy of reduction, the stability of fixation, and the presence of any associated injuries 2, 3.
• The use of a systematic approach to treatment, including careful evaluation and classification of the fracture, can help to improve outcomes and reduce complications 3, 5.