Differential Diagnosis for Ring Finger Injury Pain at the MCP Joint

• Single Most Likely Diagnosis
  • Boxer's fracture or 5th metacarpal fracture: This is a common injury that occurs when the fist is clenched and an object is struck, causing a fracture at the neck of the 5th metacarpal bone, which is near the MCP joint of the ring finger. The pain and swelling associated with this fracture could easily be mistaken for an injury at the MCP joint itself.
• Other Likely Diagnoses
  • MCP joint sprain: A sprain of the ligaments surrounding the MCP joint could cause pain and stiffness in the joint, especially if the injury involved a sudden twisting or bending motion.
  • MCP joint dislocation: Dislocation of the MCP joint can occur from a direct blow to the finger or from a fall onto the hand, causing the joint to become misaligned and resulting in pain and limited mobility.
  • Tendinitis or tenosynovitis: Inflammation of the tendons or their surrounding sheaths near the MCP joint can cause pain and stiffness, especially with movement of the finger.
• Do Not Miss Diagnoses
  • Infection (e.g., septic arthritis): Although less common, an infection within the MCP joint can lead to severe pain, swelling, and potentially serious complications if not promptly treated.
  • Osteonecrosis (avascular necrosis): This condition, where the blood supply to a bone is interrupted, can occur after a fracture or severe injury and may lead to the death of bone tissue, causing chronic pain and joint dysfunction.
• Rare Diagnoses
  • Ganglion cyst: A benign lump or mass that can develop near the MCP joint, potentially causing pain or discomfort, especially if it compresses nearby nerves or tendons.
  • Tumor (benign or malignant): Although extremely rare, tumors can occur near the MCP joint and cause pain, swelling, or limited mobility, highlighting the importance of a thorough evaluation for any unexplained or persistent symptoms.