Anomalous Flexor Carpi Radialis Anatomy During Volar Distal Radius Approach: Two Case Reports

Area of Science:

• Orthopedic Surgery
• Anatomical Studies
• Surgical Landmarks

Background:

• Volar locking plates are standard for distal radius fractures, utilizing volar approaches.
• The flexor carpi radialis (FCR) is a key superficial landmark in these approaches.
• Anatomical anomalies can complicate surgical exposure and increase risks.

Purpose of the Study:

• To report two rare anatomical variants encountered during volar approaches for distal radius fracture fixation.
• To highlight the potential complications and risks associated with these variants.
• To emphasize the importance of recognizing these anomalies for surgical safety.

Main Methods:

• Case report detailing two instances of anomalous flexor forearm musculature during open reduction and internal fixation.
• Description of surgical findings and anatomical variations.
• Review of potential impacts on surgical dissection and neurovascular structures.

Main Results:

• Encountered FCR brevis (FCRB) with anomalous pronator quadratus insertion, obscuring the typical surgical interval.
• Observed complete agenesis of the FCR, altering the radialmost tendon and increasing median nerve proximity risks.
• Both variants significantly changed expected surgical anatomy and dissection planes.

Conclusions:

• Anatomical variants like FCRB and FCR agenesis can significantly alter surgical anatomy during volar approaches.
• Recognition of these anomalies is essential for safe surgical exposure and preventing iatrogenic neurovascular injury.
• Awareness of potential muscle variations improves surgical planning and patient outcomes.