Multiple digit camptodactyly caused by anomalous ulnar sided flexor digitorum superficialis insertions

Area of Science:

• Hand surgery
• Anatomical variations
• Orthopedic surgery

Background:

• Camptodactyly, characterized by finger flexion deformities, can arise from various causes.
• The flexor digitorum superficialis (FDS) tendon plays a crucial role in finger flexion and is a potential source of pathology.

Observation:

• An anomalous insertion of the FDS tendon was identified as the cause of multiple digit camptodactyly.
• This abnormal tendon connected the FDS tendon proximal to the proximal interphalangeal (PIP) joint to the extensor expansion distal to the PIP joint.
• The anomaly was unilateral, present only on the ulnar aspect of the ring and middle fingers.

Findings:

• Division of the anomalous FDS tendon insertion successfully corrected the fixed flexion deformity at the PIP joint.
• This specific FDS tendon anomaly has not been previously documented in clinical or cadaveric literature.
• The anomaly might be missed with a volar surgical approach.

Implications:

• Recognizing this rare FDS tendon anomaly is crucial for accurate diagnosis and effective treatment of camptodactyly.
• Understanding such variations can refine surgical techniques for hand deformities.
• This finding expands the known spectrum of anatomical variations affecting finger mechanics.