Perilunate Dislocations
What is a Perilunate Dislocation?
A perilunate dislocation is a serious wrist injury where the bones surrounding the lunate (one of the small carpal bones in the center of the wrist) become dislocated. In most cases, the lunate remains in its proper alignment with the radius, while the other carpal bones shift out of place, typically toward the back of the hand (dorsal side). This type of injury is uncommon but requires immediate medical attention due to the risk of long-term complications such as nerve damage or arthritis.
Causes of Perilunate Dislocation
Perilunate dislocations typically result from high-energy trauma. The injury often occurs when the wrist is forcefully extended and rotated. Common causes include:
- Falls on an outstretched hand, especially from a height.
- Motor vehicle accidents, where the wrist is impacted against a dashboard or steering wheel.
- Sports injuries, particularly in contact or extreme sports like football, skateboarding, or snowboarding.
- Industrial or workplace accidents involving heavy machinery or falls.
These injuries often involve significant force and may also include associated fractures of the scaphoid or other carpal bones.
What are the Symptoms of a Perilunate Dislocation?
Perilunate dislocations usually cause noticeable symptoms. Patients should watch for the following signs:
- Severe wrist pain and swelling
- Visible deformity on the back of the wrist
- Limited or painful wrist movement
- Numbness or tingling, especially in the thumb, index, and middle fingers (suggestive of median nerve compression)
- Weak grip strength or difficulty using the hand
How is a Perilunate Dislocation Diagnosed?
Diagnosis typically begins with a physical examination and a review of the patient's injury history. Imaging tests are essential, including:
- X-rays of the wrist from multiple angles to identify misalignment of the carpal bones.
- CT scan may be used to assess complex bone injuries.
- MRI can help evaluate ligament damage and soft tissue involvement.
Missed diagnoses are unfortunately common, so careful radiographic analysis is key.
What are the Treatment Options for a Perilunate Dislocation?
Treatment depends on the severity of the injury and the timing of diagnosis. Options include:
- Emergency closed reduction to realign the bones temporarily and relieve pressure on nerves.
- Surgical intervention (Open Reduction and Internal Fixation, or ORIF) to repair torn ligaments and fix associated fractures.
- Immobilization with a cast or splint after surgery.
- Physical therapy to restore strength, flexibility, and function post-healing.