Differential Diagnosis
- Single most likely diagnosis
- Avulsion fracture of the second metacarpal head: This is the most likely diagnosis given the cortical discontinuity within the head of the second metacarpal, which is a direct indicator of an avulsion injury.
- Other Likely diagnoses
- Boxer's fracture (fracture of the fifth metacarpal neck): Although the findings specifically mention the second metacarpal, a boxer's fracture could present with similar soft tissue swelling and should be considered, especially if the patient's history involves a punching mechanism.
- Metacarpal head fracture (other than avulsion): The cortical discontinuity could also represent a non-avulsion type fracture of the metacarpal head, which would still require appropriate management.
- Do Not Miss diagnoses
- Osteomyelitis or septic arthritis: Although less likely, infections such as osteomyelitis or septic arthritis could present with soft tissue swelling and must be considered to avoid missing a potentially serious condition that requires prompt antibiotic treatment.
- Pathological fracture: A fracture through a pre-existing bone lesion (e.g., a cyst or tumor) could mimic an avulsion injury and is crucial to identify for appropriate management.
- Rare diagnoses
- Metacarpal osteonecrosis: This condition could potentially cause cortical irregularities and should be considered in patients with risk factors such as steroid use or sickle cell disease.
- Bone tumor (e.g., osteochondroma, enchondroma): Although rare, a bone tumor could cause cortical discontinuity and should be considered if other findings or the patient's history suggest this possibility.