A Patient's Guide to Artificial Elbow Replacement

Introduction

Artificial replacement of the elbow is becoming an increasingly successful way of treating problems caused by arthritis of the elbow joint.  It is also used more and more in fractures of the elbow in elderly patients to immediately replace a badly damaged joint.  The artificial elbow is considered successful by more than 90% of patients who have the operation.  

Anatomy

The elbow joint is a hinge - it straightens out and bends.  Inside the joint, the bones are covered with a slick, smooth material that is called articular cartilage.  Articular cartilage is the material that allows the bones to move against one another in the joints of the body.  The cartilage lining in joints is about 1/8 inch think in most non-weightbearing joints.  It can be much thicker in weightbearing jointssuch as the ankle, hip or knee.  It is soft enough to allow for shock absorbtion but tough enough to last a lifetime - as long as it is not injured.

The large muscle in the back of the arm - the triceps attaches to the point of the ulna (called the olecranon).  When this muscle contracts, it straightens out the elbow.  The biceps muscles in the front of the arm contract to bend the elbow.  The muscles that bend the elbow are called the biceps muscles. 

Causes

The most common problem that can lead to the need for an artificial elbow replacement is arthritis.  There are two main types of arthritis - degenerative and systemic arthritis.  Degenerative arthritis is also called wear and tear arthritis.  Degenerative arthritis can be due to injury of the elbow - occurring many years after a fracture or dislocation of the joint.  Degenerative arthritis is also called wear and tear arthritis.  There are many types of systemic arthritis, the most common being Rheumatoid Arthritis.  Any systemic arthritis is a disease that affects all the joints of the body, causing destruction of the articular cartilage lining of the joints.

An artificial elbow replacement may also be used immediately following certain types of fractures of the elbow - usually in elderly patients.  Elbow fractures are difficult to repair surgically in teh best of circumstances.  In many elderly patients, the bone is also weak due to osteoporosis.  The weakened bone makes it much harder for the surgeon to fix the fractured pieces of bone with metal plates and screws and hold them in position long enough for the bones to heal.  In some cases, it is more successful to simply remove the fractured pieces and replace the elbow with an artificial joint.

Symptoms

Pain is the main problem with arthritis of any joint.  This pain occurs at first only related to activity.  There may be a swelling around the joint and the joint may fill with fluid and feel tight - especially following increased activity.  When all the articular cartilage is worn off the joint surface there may be squeaking sound when the joint is moved.  Doctors refer to this sound as crepitance.  Arthritis will also eventually affect the motion of a joint.  The joint becomes stiff and loses motion.

Diagnosis

The diagnosis of the cause of elbow pain starts with a complete history and physical examination by your doctor.  He will ask about any other medical conditions, surgery in the past and medications you are currently taking.  Your dcctor will be interested in any injuries to the elbow - even years before.   

Xrays will be required to determine the extent of the degenerative process and may suggest a cause for the  degeneration.  Other tests may be required if there is reason to believe that other conditions are contributing to the degenerative process.  Blood tests may be required to rule out systemic arthritis (such as Rheumatoid Arthritis) or infection in the elbow. 
               
Treatment

The treatment of arthritis of the elbow can be divided into the non-surgical means to control the symptoms and the surgical procedures that are available to treat the condition.  Treatment usually begins when the ankle first becomes painful.  This may only occur with heavy use and may simply require mild anti-inflammatory medications such as aspirin or ibuprofen.  

Surgery is usually not considered until it has become impossible to control the symptoms without surgery.  To reveiw the options available for treatment of the arthritic elbow you may want to review:

A Patient's Guide to Degenerative Arthritis of the Elbow (separate document)


The Artifical Elbow

The artificial elbow replacement can be held in place in two ways.  Orhopaedic surgeons have long used a special type of epoxy cement to hold artificial joints in place.  A cemented prosthesis is held in place by the cement that attaches the metal to the bone.  

Some of the newer types of artificial joints, including the elbow joints, are what are known as uncemented prostheses.  An uncemented prosthesis has a fine mesh of holes on the surface that allows bone to grow into the mesh and attach the prosthesis to the bone.  The choice to use a cemented or uncemented artificial elbow is usually made by the surgeon based on your age, your lifestyle, and the surgeon's experience. 

Each prosthesis is made up of two parts.  The humeral component is the portion of the artificial joint that replaces the lower end of the upper arm bone - the humerus. The ulnar component replaces the large bone of the forearm.

The most common artificial elbow prostheses are similar to a hinge.  The humeral component has a stem which slides into the hollow center of the humerus and the ulnar component has a metal stem that slides into the hollow center of the ulna.  Between the two metal stems is a hinge made of metal and plastic.  The plastic used is very tough and very slick - (so slick and tough that you can ice skate on a sheet of the plastic with out much damage to the material). 
	

The Operation

The operation to perform an artificial elbow replacement begins with anesthesia.  The most common type of anesthesia is probably a general anesthetic or going off to sleep.  The operation can also be performed with regional anesthesia where only the nerves of the arm are put to sleep.  This means that you will be awake during the procedure.  The anesthetist can give you medications to sedate you during the operation if it is performed under regional anesthesia.  You may drift off to sleep and be unaware of the surgery.  Regional anesthesia may be safer if you have other medical problems, such as lung disease.

The operation to replace the elbow begins with an incision in the back of the elbow joint.  Following the incision the Ulnar Nerve is located and moved out of harm's way.  The elbow joint is entered from the back side.  This allows the surgeon to see the joint surfaces of the elbow.

Once the joint is exposed, the first step is to remove the joint surfaces of the ulna and the radius.  This is usually done with a surgical saw.  Once this has been done, the hollow marrow of teh ulna is prepared using a special rasp to create a space to place the stem of the ulnar component.  The ulnar component is then inserted into the bone to test the fit.  If the fit is satisfactory, attention is then turned to the humerus.

The joint surface of the humerus is removed and again the hollow marrow cavity of the humerus is prepared using a special rasp.  The humeral component is fitted into theis space to check the fit.  The surgeon will then assemble the pieces of the implant and check to see if the hinge mechanism is working correctly.  If so, the implant is removed and the bone is prepared to cement the implant in place.  The ulnar component and the humeral component are cemented in place and the hinge assembled once again.  If everything is satisfactory at that point, the surgeon will close the incision.

You will probably be placed in a bulky dressing and spint for your comfort before you are returned to the recovery room.


Complications

As with all major surgical procedures, complications can occur. Some of the most common complications following artificial elbow replacement are: 
 
          Infection 
          Loosening
	  Nerve Injury
	  
This is not intended to be a complete list of the possible complications, but are the most common. 

Infection

Infection can be a very serious complication following an artificial joint. The chance of getting an infection following most artificial joint replacements is probably somewhere around 1%-2%.  The artificial elbow replacement has a somewhat higher chance of infection.  This is due to many reasons.  The skin is thin around the elbow and there are no muscles that cover the joint, so wound complications are more common.   The operation is also more likely performed in patients who have Rheumatoid Arthritis.  This disease and the medications that are used to treat the disease affect the body's immune system, making infections more likely.  

Some infections may show up very early - before you leave the hospital. Others may not become apparent for months, or even years, after the operation. Infection can spread into the artifical joint from other infected areas. Your surgeon may want to make sure that you take antibiotics when you have dental work, or surgical procedures on your bladder and colon to reduce the risk of spreading germs to the joint. 

Loosening

The major reason that artificial joints eventually fail continues to be a process of loosening where the metal or cement meets the bone. There have been great advances in extending how long an artificial joint will last, but most will eventually loosen and require a revision.  In the past, the artificial elbow joint has not been considered as successful as the hip and knee replacement.  There has been a much higher risk of loosening and failure of the artificial elbow replacement.  The risk of loosening is much higher in younger, more active patients.  A loose prosthesis is a problem because it causes pain. Once the pain becomes unbearable, another operation will probably be required to either revise the elbow replacement, or perform an elbow fusion.

Nerve Injury

All of the nerves and blood vessels that go to the forearm and hand travel across the elbow joint.  Due to the fact that the operation is performed so close to these important structures, it is possible to injure either the nerves or the blood vessels during surgery.  The result may be temporary if the nerves have been stretched by retractors holding them out of the way.  It is very uncommon to have permanent injury to either the nerves or the blood vessels, but it is possible.

Rehabilitation