Differential Diagnosis for Inability to Extend Distal Phalange
Single Most Likely Diagnosis
- Mallet Finger: This is the most common injury affecting the extensor tendon of the distal phalange, typically resulting from a sudden, forceful flexion of the distal interphalangeal (DIP) joint, such as when a ball strikes the fingertip. The inability to extend the distal phalange actively is a hallmark of this condition.
Other Likely Diagnoses
- Distal Interphalangeal (DIP) Joint Dislocation: Dislocation of the DIP joint can lead to an inability to extend the distal phalange due to disruption of the joint surfaces and surrounding ligaments.
- Extensor Tendon Laceration or Rupture: Direct trauma to the extensor tendon can cause a laceration or rupture, leading to an inability to extend the distal phalange.
- Fracture of the Distal Phalange: A fracture, especially one involving the base of the distal phalange, can disrupt the extensor tendon's attachment, making it difficult to extend the finger.
Do Not Miss Diagnoses
- Infection (e.g., Osteomyelitis or Septic Arthritis): Although less common, infections involving the bone or joint of the distal phalange can lead to severe pain, swelling, and limited mobility, including an inability to extend the distal phalange. Missing these diagnoses can lead to serious complications.
- Neurological Conditions (e.g., Radial Nerve Palsy): While less directly related to the distal phalange, conditions affecting the radial nerve can impair extension of the wrist and fingers, including the distal phalange.
Rare Diagnoses
- Tumor of the Distal Phalange: Benign or malignant tumors affecting the bone, tendon, or soft tissue of the distal phalange can cause pain, swelling, and limited mobility.
- Scleroderma or Other Connective Tissue Diseases: These diseases can lead to fibrosis and contracture of the skin and underlying tissues, potentially limiting finger extension.
- Congenital Conditions (e.g., Camptodactyly): Certain congenital conditions can result in flexion contractures of the fingers, including the distal phalange.