Shoulder and arm pain can be caused by many disorders: Rotator Cuff Tendinosis, Rotator Cuff Tears, Biceps Tendon Disorders, Shoulder Instability, SLAP Lesions, AC Joint Instability, AC Joint Arthritis, Suprascapular Nerve Compression, Clavicle Fractures, Frozen Shoulder, Avascular Necrosis (death) of the humeral head, and Shoulder Arthritis. As many of these conditions have been well-covered in other sections of this website, this section will focus on Avascular Necrosis (AVN) of the humeral head and Shoulder Arthritis. Please note that arm pain is often referred pain from the shoulder, and so the conditions that cause both shoulder and arm pain can be the same.
The shoulder is a ball and socket joint. The name of the ball is the ‘humeral head’. Avascular Necrosis (AVN), which is also known as Osteonecrosis, means death of part of a bone. For sometimes unknown reasons, the blood supply to part of the humeral head’s joint surface can occasionally be interrupted. This is analogous to a ‘heart attack’ of bone. During a heart attack, blood is cut off from the heart, killing part of it. During a stroke, blood is cut off from the brain, killing part of it. When the blood supply is cut off to a bone, part of the bone can die, which is called AVN. It’s the same problem that occurs with Kienbock’s disease in the wrist and Osteochondritis Dissecans (OCD) in the elbow. AVN of the humeral head most commonly affects people with sickle cell anemia, sickle cell trait or other blood cell disorders, those who have a history of prolonged steroid or alcohol use, or those who have had shoulder trauma.
AVN of the humeral head can lead to severe shoulder pain and stiffness. There are different stages of AVN: Stage 1 AVN is the earliest stage and cannot yet be seen on X-ray, only MRI. MRI is the best way to diagnose AVN. Stage 2 AVN can be seen on X-ray, but the humeral head is still round and has not yet collapsed. Stage 3 AVN means that the humeral head is collapsing and is no longer round. This misshapen humeral head then leads to stage 4 AVN, which is Shoulder Arthritis.
AVN is thought by many to be due to venous congestion. As the veins of a bone become congested, the pressure within the bone builds because the ‘used’ venous blood within the bone cannot escape. This increased pressure (called ‘venous hypertension’) prevents new oxygen-carrying blood in the arteries from entering the bone, similar to how a traffic jam prevents new cars from entering a busy street. Because new blood cannot enter, the affected area of bone dies from lack of oxygen. Much of the pain in the early stages of AVN (stages 1 and 2) is thought to be due to ‘venous hypertension’, or increased pressure within the bone.
The earlier AVN is diagnosed and treated, the better. Stage 1 and stage 2 AVN can be treated by Arthroscopically-Assisted Core Decompression. Arthroscopically-Assisted Core Decompression is a minimally-invasive outpatient surgery. During Arthroscopically-Assisted Core Decompression, a drill is used to make two tunnels in the humeral head into the area of AVN. These tunnels allow the ‘used’ venous blood to leave the humeral head bone, decreasing pressure within the bone and allowing new arterial blood to enter. Bone chips are packed into the tunnels so that they can heal quicker; this does not lead to a recurrence of the AVN. Arthroscopically-Assisted Core Decompression leads to good or excellent results in over 90% with stage 1 or 2 AVN of the humeral head. Arthroscopically-Assisted Core Decompression has also been reported to provide acceptable pain relief in up to 70% those with early stage 3 disease, before significant collapse of the humeral head has occurred. It is controversial as to whether or not Arthroscopically-Assisted Core Decompression delays the progression of humeral head collapse and arthritis.
During Arthroscopically-Assisted Core Decompression, fluid is placed into the shoulder. This fluid will leak out over the first 2-3 days, and is not blood. Following surgery, the shoulder should be kept clean and dry for 3 days, and then showering is allowed. Before 3 days, bathing is fine; just keep the shoulder above water and don’t get the dressings wet. After 3 days, the wounds can get wet in the shower, just blot them dry. Don’t submerge the wounds under water until the stitches are removed, which is usually done at the first post-operative visit at 2 weeks. The elbow, wrist, forearm and hand can all be moved early on to prevent stiffness. Following Arthroscopically-Assisted Core Decompression there are no formal activity restrictions other than to avoid excessive use and trauma (falls, horseplay, sports, etc.) for 6 weeks. Therapy will be used to increase motion, if needed. A Rotator Cuff and shoulder blade muscle strengthening program is usually started approximately 2 weeks after surgery.
Once the humeral head AVN progresses to late stage 3 (significant humeral head collapse), the shoulder joint is ‘doomed’ because the humeral head is no longer round, and the humeral head will therefore need to be replaced. If this is not performed in a timely fashion, the AVN can progress to stage 4, which is Shoulder Arthritis affecting both the ball and the socket side of the shoulder joint. Humeral Head Replacement (Hemi-Arthroplasty) is ‘half’ of a Total Shoulder Replacement, as only the ball is replaced. Once the arthritis becomes advanced (Stage 4 AVN), then a Total Shoulder Replacement will be required. While a Hemi-Arthroplasty may be performed as an outpatient procedure, a Total Shoulder Replacement usually requires a hospital stay of 1-2 nights.
Shoulder Arthritis can have other causes besides AVN: Osteoarthritis (wear and tear), Rheumatoid Arthritis (a systemic inflammatory disease) and Post-Traumatic Arthritis (due to a shoulder fracture or dislocation) are the most common causes of Shoulder Arthritis. Please note that just because an X-ray shows Shoulder Arthritis, that doesn’t mean that the Shoulder Arthritis is the main ‘pain generator’ in the shoulder. Many people with Shoulder Arthritis on X-ray don’t have most of their shoulder pain from Shoulder Arthritis, but from Rotator Cuff Tendinosis or a Rotator Cuff Tear. That’s why the initial treatment of Shoulder Arthritis is very similar to the initial treatment of Rotator Cuff Tendinosis: a steroid injection to decrease inflammation and a Rotator Cuff and shoulder blade muscle strengthening program. Surgery for Shoulder Arthritis should be reserved for failure of non-operative treatment.
Older patients or those with severe Shoulder Arthritis will require a Total Shoulder Replacement. While this is effective treatment, it is also major surgery and the Total Shoulder Replacement can wear out over time (10-15 years). And once a Total Shoulder Replacement wears out, the next surgery, Revision Total Shoulder Replacement, is more complicated and doesn’t work as well. Therefore, in younger patients or those with lesser degrees of Shoulder Arthritis, Arthroscopic surgery for Shoulder Arthritis can be tried first to provide a few years of pain relief and potentially delay the need for a Total Shoulder Replacement. If there’s any question, a CT scan is the best study to evaluate Shoulder Arthritis. If the joint space between the ball and the socket is <2 mm or the bone spurs are very large, then Arthroscopic surgery for Shoulder Arthritis will probably not work.
Arthroscopic surgery for Shoulder Arthritis consists of ‘cleaning up the Shoulder Joint’, removing inflammation, loose bodies (broken off bone spurs or pieces of cartilage that can float around the joint), degenerative labral (meniscus-like) tears, loose cartilage flaps and Rotator Cuff Tendinosis. Please see the ‘Rotator Cuff’ section for more information on Arthroscopic Rotator Cuff Debridement.
Arthroscopic Rotator Cuff Debridement
In addition, a Biceps Tenodesis is usually performed to eliminate the Long Biceps Tendon as a potential source of pain. Please see the ‘Biceps Tendon Disorders of the Shoulder’ section for more information on this.
Arthroscopic Biceps Tenodesis
An Arthroscopic Capsular Release is also performed, which is the same surgery used to treat a Frozen Shoulder. During Arthroscopic Capsular Release, the Joint Capsule (the balloon of tissue around the shoulder joint) is cut to allow the ball and the socket to separate slightly, which decreases the stress on their arthritic surfaces.
Following Arthroscopic surgery for Shoulder Arthritis, 2/3 with mild arthritis have a successful result, but only 1/3 with moderate arthritis have a successful result. Those with arthritis on both the ball and the socket or a large loss of cartilage (> 2 x 2 cm) have the highest failure rate. The hope is that Arthroscopic surgery for Shoulder Arthritis can decrease (not eliminate) shoulder pain for a few years, and delay (not eliminate) the need for a future Total Shoulder Replacement.
During Arthroscopic surgery for Shoulder Arthritis, fluid is placed into the shoulder. This fluid will leak out over the first 2-3 days, and is not blood. Following surgery, the shoulder should be kept clean and dry for 24 hours, and then showering is allowed. Before 24 hours, bathing is fine; just keep the shoulder above water and don’t get the dressings wet. After 24 hours, the wounds can get wet in the shower, just blot them dry. Don’t submerge the wounds under water until the stitches are removed, which usually occurs at the first post-operative visit at 2 weeks. The elbow, wrist, forearm and hand can all be moved early on to prevent stiffness. Following Arthroscopic surgery for Shoulder Arthritis there are no formal activity restrictions. The same Rotator Cuff and shoulder blade muscle strengthening program used before surgery is usually restarted approximately 2 weeks after surgery.