Lunate Dislocation: Causes, Symptoms, Treatment, Repair, Braces, Prevention

A Lunate dislocation is a rare case of traumatic wrist injury which must be attended immediately and repaired with proper lunate dislocation surgery. Lunate dislocation results in displacement of rotation of lunate without causing any change in the position of other carpal bones. Lunate dislocation is most common in case of young adults who are full of energy that can cause dorsiflexed wrist loading. Only about 10 percent of the cases of wrist injuries lead to carpal dislocations. Lunate dislocations have very less probability in case of wrist injury even less than peri-lunate dislocation. Lunate dislocations is a result of forceful dorsiflexion which can happen in case of vehicle injury or if you fall on an out-stretched hand.

Lunate dislocation needs urgent attention and surgical treatment to avoid permanent joint dysfunction. Even in case of successful treatment, risk of degenerative arthritis and wrist instability cannot be ruled out completely.

Lunate dislocation happens in case of a blow injury to wrist or crushing of wrist. The following are the possible causes of lunate dislocation:

• A fall from certain height can cause lunate dislocation. In case of an accident if you fall on your outstretched hand.
• Injuries during sports can lead to lunate dislocation. Sports which involve contact like in-line skating or snowboarding or any incident that can make you fall on outstretched hand.
• Motor vehicle crashes are another major cause of lunate dislocation. Some severe motor vehicle crashes can lead to high-velocity injuries to wrist resulting into lunate dislocation requiring immediate surgical repair.

Lunate dislocation is associated with following signs and symptoms:

• Significant pain in the wrist and palm of hand is a major symptom of lunate dislocation.
• Swollen wrist is another symptom of lunate dislocation.
• Difficulty in moving wrist and hand.
• Tingling feeling or numbness in fingers is also seen in lunate dislocation.

Tingling and numbness in lunate dislocation is caused because of dislocation of bones into the carpal tunnel which hosts the median nerve. Thus pinching of this nerve causes tingling. A lunate dislocation is one of the main reasons behind acute onset carpal tunnel syndrome.

• In case of lunate dislocation, the person must seek attention from an expert like orthopedic surgeon to avoid further damage.
• Hand specialist can suggest proper emergency physical treatment that can reduce the damage of lunate dislocations.
• It is necessary to stay in touch of the primary care physician even after initial treatment for proper follow up of the recovery.

Certain health conditions or sports activities can make you more prone to wrist injuries and increase the risk of lunate dislocation. Risk factors for lunate dislocation are primarily caused during sports activities and secondarily caused because of certain health conditions.

Following sports activities involve a lot of risk of wrist injury and lunate dislocation:

• Wrestling
• Football
• Jumping on a trampoline
• Basketball
• Skiing
• Rugby
• In-line skating
• Hockey
• Snowboarding.

Following health conditions can further increase the risk of lunate dislocation:

• Preexisting bone diseases like osteoporosis is a risk factor for lunate dislocation.
• Smoking reduces the ability to absorb calcium and can be a factor of risk for lunate dislocation.
• Improper diet which is unable to supply bone-building calcium and vitamin D in required amounts.

Below mentioned are some of the complications of a lunate dislocation:

• In rare case if there is any fracture of distal radius, complications like vascular complications can occur.
• There may be complications in soft tissue including disruption of carpal ligaments that can cause long-term instability of carpal.
• Some patients can also have severe wrist pain.
• Even after successful surgery of lunate dislocation, there are chances of Kienbock disease or avascular necrosis of the lunate which can be a complication.

X-ray of the injured wrist can reveal the case of lunate dislocation but it required very close observation as it is a very subtle condition. Often the patient is severely injured in an accident and it is not possible to obtain X-rays of the wrist in proper position which can make it harder to evaluate the injury for lunate dislocation. MRI (Magnetic resonance imaging) and CT scan (computed tomography) are also helpful in diagnoses of lunate dislocation.

Lunate dislocation is mostly associated with other wrist injuries including tearing of ligament and other fractures. Thus a proper observation is required to get a clear understanding of the injury. Lunate bone has a shape of crescent moon and is placed at the junction of multiple bones including arm bones, wrist bones, triquetral bone, lateral scaphoid bone and ulna. The shape of the lunate bone can sometimes vary.

In case of lunate dislocation, it is required to reposition the bone correctly in its place. This can be done physically or may require surgical treatment in complex situations. Usually surgical treatment is preferred for lunate dislocation even in normal cases as it provides better stability and proper healing of the bones.

Pins are inserted temporarily to keep the bones in position after lunate dislocation surgery, which are removed later. In case of any carpel tunnel syndrome, carpel tunnel release also becomes an essential part of surgery. Surgery also looks to rectify the fractures and tearing of ligaments in the affected portion.

It is normal to have complications in case of lunate dislocation which includes persistent pain, arthritis, and instability of the wrist joint. However the complications can be avoided or reduced by immediate treatment of injury. But there is no certainty that complications will not occur. It takes at least 6 months for the patient to recover from the injury causing lunate dislocation.

Usually lunate dislocation is associated with a lot of pain and thus doctor prescribes pain killers medicines like ibuprofen (Advil, Motrin IB, others), acetaminophen (Tylenol, others), or naproxen sodium (Aleve, others). In case of severe pain special opioid medications like codeine is recommended by the doctor.

Surgical repair is a common method to treat lunate dislocation. Lunate dislocation is not an exclusive injury but happens as a part of major accident involving injury to wrist like automobile collision, accident fall from height etc… Lunate dislocation involves injury to a small bone of the wrist. In case of lunate dislocation, the carpal bone which is a small bone present in the wrist is displaced from its usual position.

Closed reduction is the initial phase of the surgical treatment of lunate dislocation and offers following three advantages:

• It helps in restoring proper alignment of carpal.
• It makes the patient feel comfortable.
• It provides perfect preparation for surgical treatment.

In the process of correcting the position of displaced lunate, the wrist is first distracted and then lunate bone is pushed from palmar to dorsal direction with the help of pressure from the thumb. This is followed by flexing of hand gently and eventually the wrist is relaxed from distraction gently. After this complex treatment procedure the wrist is fixed in a position of about 10 degrees of palmar flexion with the help of plaster splint, or cast (Colles) to allow recovery.

If closed reduction fails to rectify the lunate dislocation, doctors go for the second option of open reduction through a palmar approach. It is necessary to arrange for this alternative treatment as soon as possible to ensure that there is no damage done to median nerve and also proper supply of blood to lunate is preserved.

In this procedure first the extrinsic palmar ligaments are disrupted starting from the space of Poirier (as shown) to expose the mid-carpal joint.

Now the proper supply of blood to this joint is restored by irrigating the midcarpal joint. Surgery mainly involves removal of subchondral flakes or loose bodies which have become loose and repairing of tears with the help of interrupted sutures.

Once the splint or cast is removed after lunate dislocation surgery, you need to undergo therapy of certain physical workouts and rehabilitation exercises to get rid of the stiffness and allow easy movement of the wrist gradually. Rehabilitation is a gradual process that needs to be continued for some months or may be more get your wrist working in the normal condition and give time for proper healing.

The time taken to recover from lunate dislocation depends on a lot of factors like severity of injury, mode of treatment etc… and thus you need to consult your doctor to find the exact recovery period/healing time or for resolution of any particular issues related to lunate dislocation.

Wrist braces are very helpful in recovery and treatment of lunate dislocation used as a part of rehabilitation processes. They keep the wrist joint intact and also help in healing by application of heat and compressive force on the ligaments and bones of the wrist. As of the latest materials used for making braces include neoprene or strong tissue nylon fabrics allow a very little movement keeping joint intact. Velcro is used as an adherence in this process. Sometimes braces also include use of metal “spines” for ensuring better fixation of the joint and least mobility.

Lunate dislocation is mostly associated with severe chronic wrist pain or instability of wrist. Although the prognosis/outlook for lunate dislocation is good, it is necessary to understand that lunate dislocation is a part of major wrist injury involving damage to carpal ligaments. Thus it is common to have long term carpal instability in case of lunate dislocation.

The situation of lunate dislocation cannot be avoided but can be prevented by taking following measures:

1. Increase Strength of bones to Prevent Lunate Dislocation

   Improve the strength of your bones or build strong bones by:

   • Ensuring that your diet includes required amount of calcium and vitamin D.
   • Including weight-bearing exercises in your routine like brisk walking.
   • Getting rid of smoking if you smoke.

2. Prevent Falls to Avoid Lunate Dislocation

   The injury to the wrist or lunate dislocation can be avoided by minimizing chances of falling:

   • Wear shoes with good gripping to avoid falling and prevent lunate dislocation.
   • Get rid of home hazards.
   • Ensure good lighting in your living space.
   • Ensure that your vision is right.
   • Use of grab bars in bathroom is very helpful in preventing falls.
   • Always have handrails in the stairs.
   • Watch for slippery surfaces and be more careful while walking.

3. Use Protective Gear for Athletic Activities to Prevent Lunate Dislocation

   It is recommended to use wrist guards to prevent lunate dislocation while engaging in high-risk activities like:

   • Rugby.
   • In-line skating.
   • Snowboarding.
   • Football.

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