What is Shoulder Arthritis?
The bones of the shoulder are the humerus, scapula, and clavicle. There are three main joints formed by these bones including the acromioclavicular joint, the sternoclavicular joint, and the glenohumeral joint. The acromioclavicular or AC joint is formed by the highest point of the scapula (known as the acromion), and the clavicle. The sternoclavicular joint is formed by the intersection of the sternum and the clavicle. The glenohumeral joint is the “ball-and-socket” joint of the shoulder formed by the head or “ball” of the humerus and the cup or “socket” of the glenoid (which is the lateral part of the scapula). The glenohumeral joint allows a greater range of motion than any other joint in the body. In a healthy joint, cartilage forms a protective layer between bones, allowing for fluid articulation of the arm, while still maintaining stability. If the joint becomes arthritic, meaning the cartilage wears out, both mobility and stability of the shoulder may be compromised as damage to this cartilage allows bone-on-bone contact and deterioration of the bones. Bone spurs may also develop causing increased pain and functional loss.
Arthritis may develop in the glenohumeral joint for a number of reasons including degeneration with aging (osteoarthritis), persistent inflammation (rheumatoid arthritis), loss of blood supply (avascular necrosis), or as a result of previous injury such as a fracture or dislocation. Overall, shoulder joint arthritis is most common to patients over the age of 50 and in patients with a prior history of shoulder injury.
Signs and Symptoms:
Patients may notice a deep ache within the shoulder joint that worsens with activity, and may be more severe at night. As the symptoms intensify, patients may notice locking, clicking, or grinding within the joint, followed by weakness, instability, and loss of motion. There may also be noticeable inflammatory swelling or tenderness in the shoulder region.
Conservative options include rest and reduction of activities that incite pain, as well as ice, anti-inflammatory medications, or steroid injections to temporarily reduce pain and swelling. Gentle stretching and strengthening exercises may aid in flexibility and maintenance of function.
Surgery may be recommended if conservative treatment is not effective in managing pain and preserving function. Occasionally, debridement of the joint alone will offer temporary relief of symptoms, but in most cases, joint replacement surgery is more effective in reducing symptoms long-term. The goals of joint replacement surgery are to stabilize the shoulder, to restore range of motion, and to reinstate smooth articulation of the shoulder joint. The severity of the shoulder condition will determine whether a partial joint replacement will be sufficient, or if a total joint replacement will be required to reduce pain and improve strength and motion within a severely damaged joint. The three most common surgical joint replacement procedures are 1) Humeral Head Resurfacing Arthroplasty which replaces the humeral head, 2) Hemi-Arthroplasty which replaces the humeral head and is secured by placement of a stem inside the humerus, and 3) Total Shoulder Replacement which replaces the humeral head and the glenoid, and also places a stem inside the humerus.
1) Humeral Head Resurfacing Arthroplasty is a simple and reliable surgical option for repairing damage to the shoulder joint caused by arthritis. This procedure is intended to better approximate the natural anatomy of a damaged or arthritic humeral head and to allow the joint to regain mobility and stability. Resurfacing arthroplasty involves reshaping the humeral head, drilling a small hole in the humerus to anchor the implant with, and essentially securing a cap over the existing humeral head.
Indications: Resurfacing arthroplasty may be used for stable rheumatoid patients, younger patients with osteoarthritis or with avascular necrosis (death of bone tissue due to a lack of blood supply), as well as patients with shoulder instability, post-traumatic arthritis, and shoulder chondrolysis (a destruction of the joint cartilage in the shoulder), if they have a smooth well-matched glenoid. Patients with active infection, very unstable shoulders, paralysis of the shoulder due to nerve injury, or very poor soft bone may be unable to support the resurfaced head, and thus are not good candidates for resurfacing arthroplasty.
Advantages: The most current prosthesis for resurfacing arthroplasty has a peg with an in-growth surface that allows bone to grow inward towards the peg—providing long term stability to the head surface. Additionally, the undersurface of the prosthesis is coated with the protein-rich substance hydroxyapatite, which further improves bone in-growth. Resurfacing arthroplasty also allows more preservation of the original bone, reduction of prosthetic fracture, and reduction of intra-operative complications such as blood loss than other arthroplasties. These patients require fewer revisions than other options, and if revision is necessary with time, it is an easier revision to make as bone cement is often not used in resurfacing arthroplasty. Lastly, resurfacing of the humeral head more closely approximates the natural shape of the joint than the other options.
Surgery: In preparation for the surgery, a general anesthetic is usually used and most patients will receive a regional block to reduce pain after surgery. The block “deadens” the shoulder area. The surgeon will make an 8-10 cm incision in the front of the shoulder. The surface of the humeral head will be shaved down and a small hole will be drilled in the humerus. A prosthetic metal cap will then press fit onto the existing humeral head after convex reaming of the head. Often a temporary drain is placed overnight to reduce the chance of developing a post-operative hematoma. Surgery usually takes about 2 hours.
Rehabilitation: This procedure is usually performed at the hospital with an overnight period of observation. Following surgery, the arm is placed in a shoulder sling with a waist belt (shoulder immobilizer). Gentle pendulum swings are begun within 24-48 hours of surgery. Light active range of motion exercises begin once the pain block wears off and sensation returns. The use of the sling can be discontinued at about 3 weeks. There should be no external rotation past neutral for six weeks. This is the main protection for the shoulder and allows the anterior muscle/tendon attachment to heal. At 6-8 weeks progressive stretch and strengthening exercises begin. Return to reduced activities is allowed as the patient is able. Light activities usually begin at 8-12 weeks, and moderate activities by 16-18 weeks. The shoulder may continue to improve for about 1½ years.
2) Hemi-Arthroplasty is a partial joint replacement surgery to repair arthritic damage to the glenohumeral shoulder joint. The “ball” (humeral head) is removed and a prosthetic head and stem are secured to the humerus to partially recreate the glenohumeral joint.
Indications: Hemi-arthroplasty is usually recommended when primarily the humeral head is arthritic and the proximal humerus is very soft, osteoporotic, or has moderate bone loss from fracture. Patients whose work or sport requires heavy demands on the joint may also be candidates for hemi-arthroplasty. Patients will a severe loss of glenoid cartilage, incongruent glenoid and humeral surfaces, or marked instability may not be candidates for hemi-arthroplasty.
Advantages: Hemi-arthroplasty is a less invasive procedure and has less risk of loosening with time than total shoulder replacement. In total shoulder replacement, the glenoid component is the portion that becomes loose and may require revision with time. Hemi-arthroplasty can be revised to total shoulder arthroplasty later if necessary.
Surgery: In preparation for the surgery, a general anesthetic is usually used and most patients will receive a block to reduce pain after surgery. The block “deadens” the shoulder area. The surgeon will make an 8-10 cm incision in the front of the shoulder. Often a temporary drain is placed for 1-2 days to reduce the chance of developing a post-operative hematoma. Hemi-arthroplasty is performed on an inpatient basis. The humeral head will be removed, and the humerus will then be hollowed out to secure the stem of the implant. Some patients will require cementation of the humeral implant into the bone if the bone is soft, while others may only require a “press-fit” of the humeral implant into the bone. The metal humeral head is then attached to the stem implant to complete the humeral joint replacement. The prosthetic humerus is then reduced to the original glenoid to form the hemi-arthroplasty. Often a temporary drain is placed for 1-2 days to reduce the chance of developing a post-operative hematoma. Surgery usually takes about 2 ½-3 hours.
Rehabilitation: Following surgery, a patient is typically admitted overnight in the hospital for pain meds, IV antibiotics, and observation. Rehabilitation begins immediately following surgery with slow passive forward flexion. The drain will be removed the day following surgery and a sling immobilizer will be worn except during exercises. Physical therapy appointments will begin at 3 days post op and the sutures will be removed at 2 weeks. Therapy will continue for several months, beginning with stretching and range of motion exercises during weeks 1-5 and gentle strengthening exercises starting at 6-8 weeks. Patient may expect to return to lighter activities between 3-6 months (fishing, golf tennis), and full activity by about 6 months (hunting), although improvement may continue for 1-1 ½ years after surgery.
3) Total Shoulder Replacement is most commonly performed in an effort to alleviate shoulder joint pain associated with severe arthritis of glenoid and humeral head. Damage to the glenohumeral joint is reconstructed by removing the “ball” (humeral head) and reaming the “socket” (glenoid cup) of the joint and placing prosthetic implants to replace the entire joint. A metal ball attached to a stem is secured in the humerus, and an artificial cup is cemented to replace the glenoid.
Indications: Total Shoulder Replacement surgery is recommended to relieve pain if nonsurgical treatments and/or other arthroscopic shoulder surgeries have failed leaving bone on bone contact and sheering. It is considered when both joint surfaces are severely damaged, yet both are still able to be reconstructed. Often, patients with severe forms of osteoarthritis, rheumatoid arthritis, post-traumatic arthritis, marked instability, avascular necrosis (lack of blood supply to a bone within the joint), or complex fractures may be candidates for total shoulder replacement.
Advantages: By replacing the entire shoulder joint, a better fulcrum for smooth movement can be achieved with decreased friction. When the total joint is replaced, arthritic progress is impeded. Pain relief as well as strength and stability can also be greatly improved. One disadvantage is that the glenoid is the weak link and can loosen with time.
Surgery: In preparation for the surgery, a general anesthetic is usually used and most patients will receive a block to reduce pain after surgery. The block “deadens” the shoulder area. The surgeon will make an 8-10 cm incision in the front of the shoulder. Often a temporary drain is placed for 2-3 days to reduce the chance of developing a post-operative hematoma. Total joint replacement is performed on an inpatient basis. The humeral head will be removed, the glenoid will be reshaped, and a plastic glenoid implant will be placed. The humerus will then be hollowed out to secure the stem of the implant. Some patients will require cementation of the humeral implant into the bone if the bone is soft, while others may only require a “press-fit” of the humeral implant into the bone. (The glenoid implant usually requires cementation with bone cement.) The metal humeral head is then attached to the stem implant and the humerus and glenoid are reduced to form the new joint. Often a temporary drain is placed for 1-2 days to reduce the chance of developing a post-operative hematoma. Surgery usually takes about 3-4 hours.
Rehabilitation: A patient is typically admitted for 24-48 hours in the hospital for pain meds, IV antibiotics, and observation. The drain will be pulled prior to leaving the hospital, and an extensive rehabilitation program will begin with home exercises 6 times a day and weekly visits to therapy. A cryocuff or ice should be used until the first follow up visit at 2 weeks. Sutures will be removed at 2 weeks. An arm sling immobilizer is worn at all times for several weeks except during exercises and simple daily activities that involve lifting no more than the weight of a coffee cup. Strengthening activities that involve internal and external rotation are to be avoided for 6 weeks. Patient may expect to return to full activity by about 6 months, although improvement may continue for 1-1 ½ years after surgery.
Although rare, if the above listed procedures fail to produce results, Reverse Shoulder Arthroplasty (where an artificial ball is placed at the glenoid, and an artificial socket is placed at the humeral head) or Glenohumeral Arthrodesis (total fusion of the joint) may be recommended as salvage options.
Surface replacement arthroplasty. Ofer Levy MD. Advanced Reconstruction: Shoulder. American Academy of Orthopedic Surgeons. 2007
Current Trends in Shoulder Arthroplasty. The American Journal of Orthopedics. December 2007 Vol. XXXVI, Number 12S.
Treatment of Glenohumeral Arthritis with a Hemi-arthroplasty: A Minimum Five Year Follow-up Outcome Study. Michael A. Wirth et al. JBJS Online 2006
Surface replacement for shoulder arthritis: Surgery with a CAP, a special type of conservative resurfacing joint replacement that resurfaces the ball of the ball and socket joint, can lessen pain and improve function. Frederick A Matsen III, MD, Winston J. Warme, MD. Jan, 09, 2008. www.orthop.washington.edu