Finger / Thumb – Radial collateral ligament tear

CASE HISTORY

• Table saw injury concern for flexor tendon tear

TECHNICAL FACTORS

• Long- and short-axis fat- and water-weighted images were performed

KEY IMAGES

CASE FINDINGS

• Interosseous ganglion within the radial margin head first MC and base of the proximal phalanx. Advanced arthropathic subchondral geode and cyst of the proximal first MT with the trapezium and lesser degree of the trapezoid. Macrofracture with saw blade-type erosion volar base distal phalanx of the thumb series 701 images 8 and 9 series 6 image 8 with millimeter sized rim of proximal epiphyseal cortex
• Subchondral erosions involve the dorsum first metacarpal base of the first metacarpal with regional pannus and volar spurring at the MCP articulation. Osteoarthritis and gout both considerations
• A1 A Variable pulleys intact proximal phalanx of the thumb. At the mid diaphysis retracted severed FPL stump retraction sagittally measures 1.2cm
• Stretch injury involving the radial-sided pulley at the IP joint (short-axis 401 image 1)
• Radial and ulnar collateral ligaments at the IP joint of the thumb are seen in obliquity with signal hyperintensity of the radial-sided ligament insertion
• Chronic partial tear of the ulnar collateral ligament first MCP articulation non-Stener type

CASE CONCLUSION

• Lacerated tendon of the flexor pollicis longus retracted 12mm to the AO pulley mid diaphysis well demonstrated series 1001 image 7
• Traumatic cortical break along the volar and radial margin proximal phalanx of the thumb. Plain film correlation would be useful
• Swelling distal phalanx with associated laceration and partial thickness tear of the proper radial collateral ligament