The reverse total shoulder replacement arthroplasty enables experienced shoulder surgeons to treat patients with conditions that previously had no solution. These conditions include rotator cuff tear arthropathy, instability with anterosuperior escape, pseudoparalysis, and failures of surgery for arthritis and facture management.
Rotator cuff tear arthropathy (arthritis with a large cuff defect) is a devastating condition that seriously compromises the comfort and function of the shoulder. This condition is characterized by the irreparable loss of the rotator cuff tendons and destruction of the normal joint surface of the shoulder. Because these tissues cannot be restored, the shoulder is often weak painful and unstable. Using special techniques and a reversed total shoulder design qualified surgeons can improve the stability of the shoulder and enable the deltoid muscle to power it, even in the absence of a normal rotator cuff.
By contrast, when the rotator cuff is intact, shoulder arthritis is often best treated by a Total shoulder replacment In certain milder cases of rotator cuff tear arthropathy without instability a special prosthesis with a CTA head may be indicated.
Failed conventional shoulder joint replacements and failed fracture surgery may also be treatable using a reverse total shoulder replacement.
In the normal shoulder, the rotator cuff muscles, including the supraspinatus, help balance the ball of the arm bone (humeral head) in the socket against the upward pull of the deltoid muscle
In rotator cuff tear arthropathy, the rotator cuff tendons that normally are interposed between the humeral head and the overlying coracoacromial arch become progressively thinned until the humeral head moves upwards and rubs against the bone of the arch
In the early stages of rotator cuff tear arthropathy, the humeral head remains centered in the socket (glenoid) in spite of a large rotator cuff tear In later stages of rotator cuff tear arthropathy, the humeral head migrates upwards but is stabilized by the overlying coracoacromial arch in spite of the lack of rotator cuff . In the severe stage of rotator cuff tear arthropathy, the humeral head is unstable, migrating upwards and forwards because it is no longer held in position by the coracoacromial arch. This condition often arises after previous procedures, such as an acromioplasty performed in the presence of a large cuff tear . In this situation the arm often cannot be raised from the side even though the deltoid muscle is working; this is called 'pseudoparalysis'.
After performing a clinical exam, a shoulder surgeon experienced with rotator cuff tear arthropathy can suggest what type of surgery is most likely to be helpful to the individual with the condition. Individuals are most likely to benefit from reverse shoulder replacement surger if they are well motivated and in good health.
Shoulders with active elevation of 90 degrees or more (indicating good deltoid tension and stability) may be treated with shoulder arthroplasty using a cuff tear arthropathy (CTA) prosthesis.
Shoulders with anterosuperior escape and pseudoparalysis (inability to actively raise the arm above 45 degrees) are considered for the reversed total shoulder prosthesis because other options may not provide sufficient stability for the humeral head (ball of the shoulder joint). The reversed total shoulder prosthesis is designed with a socket where the ball (head of the humerus) is normally located and a ball where the socket (glenoid) is usually located. This configuration adds stability so that the deltoid muscle can power the shoulder.
The goal of reverse total shoulder replacement is to restore some function to the joint destroyed by cuff tear arthropathy. Reverse total shoulder replacement restores function by providing stability and a fulcrum against which the deltoid muscle can help elevate the shoulder to a level where some basic shoulder functions can be performed.
Reverse total shoulder replacement is a highly technical procedure and is best performed by a surgical team who has experience with this surgery. Such a team can maximize the benefit and minimize the risks of surgery.
The two-hour reverse total shoulder replacement is performed under general anesthesia.
Use of the arm is started several weeks after the procedure. Extensive therapy is not needed with reverse shoulder surgery.
This procedure does not restore the ability of the shoulder to perform heavy work or sport.
Characteristics of rotator cuff tear arthropathy
Rotator cuff tear arthropathy (or shoulder arthritis with a large rotator cuff tear) is a severe and complex form of shoulder arthritis in which the shoulder has lost not only the cartilage that normally covers its joint surface, but also the tendons of the rotator cuff tear, which help position and power the joint
Normally the tendons of the rotator cuff (large arrows in Fig. 9) allow smooth motion of the upper end of the arm bone (humerus) beneath the overlying bones, ligaments, tendons, and muscles
When the rotator cuff is degenerated chronically, torn, or otherwise deficient, the normally smooth upper surface of the upper end of the arm bone (humeral head) is unprotected from rubbing the undersurface of the bone and ligaments above (See the large arrow in
In cuff tear arthropathy, the upper surface of the ball of the upper arm bone (humeral head) becomes roughened as it rubs against the overlying bone (the acromion). This condition results in shoulder pain, weakness, stiffness, and grinding on movement.
Shoulder arthritis with a massive cuff defect must be distinguished from arthritis without substantial rotator cuff involvement, from isolated rotator cuff disease, from frozen shoulder, and from neck arthritis; each of which may produce somewhat similar symptoms. Arthritis usually gives rise to stiffness without weakness. Rotator cuff tears usually cause pain and weakness but stiffness is less common. Frozen shoulder is characterized by shoulder stiffness but the X-rays are usually normal. Neck arthritis may cause shoulder pain and weakness that is worse when the head is held in certain positions.
Incidence and risk factors
Rotator cuff tear arthropathy (or shoulder arthritis with a large rotator cuff tear) most commonly occurs in individuals over the age of 65 and is more common in women than men.
Rotator cuff tear arthropathy (or shoulder arthritis with a large rotator cuff tear) is diagnosed by a history of progressive loss of shoulder function usually without an injury along with a physical examination showing weakness and grinding on movement and a typical appearance on X-ray. In these films the humeral head can be seen contacting the undersurface of the coracoacromial arch (indicated by the arrows in Fig. 12). The most important test for cuff tear arthropathy is the x-ray characteristically showing rounding off of the humeral head as it contacts with the undersurface of the coracoacromial arch.
Rotator cuff tear arthropathy (arthritis of the shoulder associated with a massive cuff tear) is best diagnosed by an orthopedic surgeon with experience in shoulder disorders. Certain surgeons specialize in rotator cuff tear arthropathy (arthritis of the shoulder associated with a massive cuff tear).
Mild analgesic medications may relieve some of the symptoms of cuff tear arthropathy.
If the symptoms of rotator cuff tear arthropathy (shoulder arthritis with a massive rotator cuff tear) are mild the condition may be treated with.
When exercises are not successful most cases of cuff tear arthropathy are considered possible candidates for shoulder joint replacement arthroplasty with a cuff tear arthropathy (CTA) head prosthesis that allows arthritic shoulders to regain some of their lost comfort and function. However, when the shoulder is no longer stabilized with the ball in the socket consideration can be given to a reversed (reverse Delta) prosthesis.
Joint replacement surgery can improve the mechanics of the shoulder but cannot make the joint as good as it was before the onset of rotator cuff tear arthropathy. The effectiveness of the procedure depends on the health and motivation of the individual, the condition of the shoulder, and the expertise of the surgeon. When performed by an experienced surgeon, shoulder replacement arthroplasty with reversed (reverse Delta) prosthesis can provide improved stability along with improved shoulder comfort and function.
The greatest improvements patients experience after reverse shoulder replacement are in the ability to sleep and to perform some of the simple activities of daily living. In that the tendons of the rotator cuff are not repairable in this condition, normal strength and function of the shoulder cannot be regained.
Types of surgery recommended
Three types of surgery can be helpful in the management of rotator cuff tear arthropathy (shoulder arthritis associated with massive rotator cuff defects). The surgical procedures can range from a simple smoothing of the roughened bone to a resurfacing of the humeral head with a smooth prosthesis, such as one with a (CTA) head fixed to the shaft of the arm bone (humerus) (See Fig. 14). If the joint is unstable a reversed prosthesis such as the reverse Delta (See Fig. 15). may be needed.