The term luxation means total dislocation whereas subluxation means partial dislocation. A subluxation occurs due to partial displacement of articular surfaces but retaining some contact with each other.
The joint located at the wrist between the ulna and the radius which are the bones of the forearm is known as the distal radioulnar joint. Generally the injury causing subluxation to the distal radioulnar joint could be simple in nature but this often causes fracture to either of the bones.
Partial dislocation of the distal radioulnar joint (DRUJ) without a fracture is known as distal radioulnar joint subluxation. Distal Radioulnar Joint (DRUJ) Subluxation is not easy to perceive on initial presentation as there is no visible appearance of positional deformity.
Types of Distal Radioulnar Joint (DRUJ) Subluxation
There are two types of distal radioulnar joint (DRUJ) dislocations known as:
- Simple dislocation.
- Complex dislocation.
Simple Dislocation: This type of dislocation is very simple in nature. A Simple dislocation can be reduced on its own or by closing it with minimal effort.
Complex Dislocation: This type of dislocation is very complex in nature. Complex dislocation often involves easily subluxable or dislocatible or irreducible joint resulting from interposition of the extensorcarpi ulnaris tendon, the ruptured triangular fibrocartilage ligaments, the extensors of the ring and little fingers and the extensor digiti minimi tendon. Majority of the complex distal radioulnar joint dislocations are frequently associated with ulnar styloid fracture and high-energy injuries.
Causes of Distal Radioulnar Joint (DRUJ) Subluxation
- Radioulnar joint dislocation is caused by falling down on outstretched hands.
- Radioulnar joint dislocation may also be caused due to oversupination, which means turning of the palm in the upwards direction during the fall, and overpronation, which means turning of the palm in downwards direction, forces resulting from the falls on the wrist or hand.
- Dislocation of the distal radioulnar joint (DRUJ), triangular fibrocartilage complex (TFCC) tears, and midcarpal instability may also occur by traumatic fall or by performing repetitive movements in sports such as golf, racquet sports and gymnastics.
- Injuries like hypersupination and hyperpronation injuries may also cause isolated dislocation.
Signs and Symptoms of Distal Radioulnar Joint (DRUJ) Subluxation
- Wrist pain after the trauma.
- Development of swelling.
- Feeling of tenderness while touching the wrist. Pain with turning over of the hand.
- Pain during movements of the hand.
- Wrist may become deformed.
- Excessive prominence of the ulnar head.
- Narrowing of the wrist when compared to the unaffected wrist.
- Difficulty while moving the wrist.
Treatment for Distal Radioulnar Joint (DRUJ) Subluxation
Nonsurgical Treatment: Simple DRUJ subluxation is treated conservatively, which involves immobilization of the joint for six weeks in a cast. The position of the forearm while casting depends upon the type of dislocation i.e., ulnar dorsal dislocation or ulnar volar dislocation.
There are cases where closed reduction is required where the joint moves out from its normal position and impairs use of arm or wrists. Closed reduction involves nonsurgical reduction of the joint under local anesthesia to restore it to its normal position. Once the joint is aligned back to its normal position, a cast or splint may be applied. Additional percutaneous K-wire fixation is sometimes used if the joint does not retain its normal position even after reduction.
Surgical Treatment: In some cases of acute DRUJ subluxation where manual therapy fails, surgery is warranted. This procedure is called as open reduction.
Surgery is done by making a small incision to look at the fracture and get it back to its usual position by sometimes using devices such as pins, screws, etc.
Surgical procedures have risks of bleeding, neurovascular damage, etc.
Physical Therapy (PT): Physical therapy is imperative for speedier healing and restoring adequate function of wrist and hands like:
- Joint mobilizations.
- Soft tissue massages.
- Dry needling.
- Improving strength and flexibility through exercises.
- Activity retraining.
- Plans for returning to activity.
Exercises for Distal Radioulnar Joint (DRUJ) Subluxation
Exercises to strengthen up the joints is needed while recovering to obtain full motion of the joint.
Stretching Exercises for Distal Radioulnar Joint (DRUJ) Subluxation
- Flexion: To do this exercise, the wrist is bent forward until it is painless. It is held like this for 10 seconds. It is done 15 times at least twice.
- Extension: To do this exercise, the wrist is bent backwards until it is painless. It is held like this for 10 seconds. It is done 15 times at least twice.
- Side to Side: To do this exercise, the wrist is moved sideways until it is painless. It is held like this for 10 seconds. It is done 15 times at least twice.
Strengthening Exercises for Distal Radioulnar Joint (DRUJ) Subluxation
- Wrist Flexion: To do this exercise, any object resembles a handle can be used and is to be held with palms in upward direction. Then wrist is bent upwards and the weight is steadily decreased. It is done twice with at least 15 times each with gradually increasing the weight of the object.
- Wrist Extension: To do this exercise, any object resembles a handle can be used and is to be held with palms in downward direction. Then wrist is bent upwards and the weight is steadily decreased. It is done twice with at least 15 times each with gradually increasing the weight of the object
- Grip Strengthening: For this, a soft object is chosen which can be squeezed as much as possible without aggravating pain. It has to be done for 10 seconds and repeated at least 10 times.
Investigations for Distal Radioulnar Joint (DRUJ) Subluxation
A detailed examination is done for a distal radioulnar joint subluxation. X-rays are done to look for other fractures. Other tests that can be conducted include:
- CT scan.