A Diagnostic Algorithm to Guide Operative Intervention of Zone 5 Flexor Injuries

Area of Science:

• Orthopedic Surgery
• Hand Surgery
• Trauma Surgery

Background:

• Accurate diagnosis of zone 5 flexor injuries is critical due to the importance of volar forearm neurovascular structures.
• Zone 5 flexor injuries require careful evaluation to differentiate between tendinous and muscle belly involvement.

Purpose of the Study:

• To test the hypothesis that tendinous injury is more likely in the distal 50% of the forearm and muscle belly injury in the proximal 50%.
• To evaluate the diagnostic accuracy of physical examination for neurovascular and musculotendinous injuries in zone 5 flexor lacerations.

Main Methods:

• Prospective clinical study of 18 patients with zone 5 flexor lacerations from December 2015 to December 2016.
• Exclusion criteria included concomitant ipsilateral injuries in zones 1-4, multiple zone 5 lacerations, prior neurovascular injuries, crush injuries, and delayed operative exploration.
• Physical examination findings were recorded and compared with operative exploration results, analyzing injury patterns based on proximal versus distal forearm location.

Main Results:

• Distal forearm lacerations (n=14) showed a higher incidence of tendon injury (64%).
• Proximal forearm lacerations (n=5) exclusively involved muscle belly injuries, with no tendinous injuries observed.
• Physical examination demonstrated high accuracy for nerve injuries (93%-100%) but lower accuracy for arterial injuries (79%-80%).

Conclusions:

• Proximal zone 5 lacerations are less likely to involve tendon injuries and more likely to involve muscle belly injuries.
• Physical examination is reliable for detecting neurovascular injuries in zone 5 flexor lacerations.
• Patients with proximal zone 5 lacerations and no signs of nerve or arterial injury may be managed non-operatively, avoiding immediate surgical exploration.