Description 1,2,3
A total shoulder replacement (TSR) is a surgical procedure that entails replacing the articulating surfaces of the shoulder joint in order to decrease pain and regain function. This is performed for people who have a debilitating chronic pathology or have suffered a severe trauma. A TSR has similar components as a total hip replacement. A TSR involves removing the humeral head and the glenoid surface and replacing them with artificial implants. This procedure is used after conservative measures have failed to control pain and improve shoulder function.
Anatomy 4
The shoulder creates a ball and socket joint between the head of the humerus and glenoid cavity on the lateral aspect of the scapula. The articulating surfaces are covered in a hyaline cartilage which facilitates the bones gliding over each other. The joint is surrounded by a joint capsule and supporting ligaments, which are affected during the surgery and described below. The rotator cuff muscles consist of four muscles that lie close to the joint. They are responsible for the dynamic stability of the glenohumeral (GH) joint, and they assist in abducting and laterally and medially rotating the arm.
Muscles of the Shoulder:
The rotator cuff muscles (see pictures above) include the supraspinatus superior to the spine of the scapula, the infraspinatus along the inferior aspect of the spine of the scapula, the teres minor assisting with lateral rotation of the arm at the glenohumeral joint, and the subscapularis covering the underside of the scapula.
The pectoralis major and minor muscles lie anterior to the shoulder and assist in flexion, medial rotation, and adduction of the GH joint.
The deltoid muscle is divided into three parts (anterior, middle, posterior) which surround the shoulder and aid with abduction, extension, and flexion of the arm.
Ligaments of the Glenohumeral Joint (see image to the right):
Because the glenohumeral joint components are replaced in total shoulder replacement surgery, the following ligaments will be affected:
- Superior, middle, and inferior glenohumeral ligaments
- From the superomedial area of the glenoid cavity to the lesser tubercle on the humerus
-Coracohumeral ligament
- Located superiorly, between the base of the coracoid process and the greater tubercle of the humerus
- Transverse humeral ligament
- Located between the greater and lesser tubercles holding the long head of the biceps brachii tendon into the intertubercular sulcus.
Prognosis and Post-Op Complications11,12,13,14,15
Total shoulder replacement surgery offers a good prognosis. Most patients experience a decrease in pain, stiffness, improved motion and strength, enhanced function, and overall better quality of life after their procedure.
Just like any other surgery, total shoulder replacement comes with potential post operative complications. The most common are prosthetic loosening, glenohumeral instability, periprosthetic fracture, rotator cuff tears, infection, and neural injury.
The most common complication is component loosening, which usually requires a revision. A study in the Journal of Shoulder and Elbow Surgery reported a 5 year survival rate is 100% and the 10 year survival rate is 92% for TSA. Instability is only estimated to be found in 5% of cases. It is usually caused by a combination of poor component position and soft-tissue imbalance. Periprosthetic fracture may happen intraoperatively or postoperatively. Intraoperative fractures most commonly occur in patients with rheumatoid arthritis and usually happen when the humerus is rotated for exposure. Postoperative rotator cuff tears have been associated with multiple surgeries, overstuffing of the joint, overly aggressive therapy involving external rotation during early stages of rehabilitation, and tendon compromise by lengthening techniques. The prevalence of neural injury and infection have both been shown to be very low (<1%). Of nerve injuries noted, most occur to the axillary nerve and the majority spontaneously resolve over time. Infections usually occur in individuals who are immunosuppressed. Although rare, infection can be very devastating.
TSAs have been associated with less mortality and morbidity than THAs and TKAs. There seems to be no additional concern of post-op complications among the elderly population compared to younger populations, as one study showed no difference in complications between patients greater than 80 years of age and patients less than 70 years of age. The only difference noted was that the older patients may require longer institutional care before returning home.
Post-Operative Treatment16,17,18
There are many rehabilitation protocols for post-TSA rehabilitation and they all follow similar progressions. Generally rehabilitation begins with gentle passive range of motion with external rotation limitations early on, cryotherapy, scapular isometric exercises, and eventual progression to active assisted range of motion. The following stages progress from early strengthening and range of motion, to neuromuscular control, and finally functional activities. The goal of rehabilitation is to optimize patient performance in each area of treatment noted above.
There is no standardized protocol that is supported by the literature, but all protocols seem to follow a similar progression. Slight differences between protocols include the amount of external rotation limited (examples: avoid 30 degrees, 20 degrees, or excessive/sudden movement), the time frame for each stage progression, and the total rehabilitation time (examples: 12 weeks+, 16-24, or 24+). The differences are based on the physicians preferences and how the surgical procedure was performed. While minor differences behind the protocols exist, the goals for TSR rehabilitation (full range of motion, strength, neuromuscular control, and function) remain the same.
The Brigham and Women’s Hospital provides one detailed example of a post-operative rehabilitation protocol for total shoulder replacements. It includes phases of treatment, limitations and permitted movements.
The Brigham and Women's Hospital: TSR Protocol
http://ishwaryatechnosolutions.com
Outcome Measures19
Many outcome measures exist for shoulder function. The ones listed below have been commonly used and validated (with the exception of the UCLA Shoulder Score) in patients with total shoulder replacement.
American Shoulder and Elbow Surgeons (ASES) Shoulder Outcome Score
The ASES Shoulder Outcome Score is a 10 item questionnaire that is scored from 0-100 based on pain, instability, and ADLs. This portion of the test takes 3-5 minutes to administer and 2 minutes to score. The test also includes sections of objective data to be taken by the examiner that are not included in the score. It has been validated in patients aged 20-81 years. The minimal clinically important difference (MCID) is 6.4 and the minimal detectable change (MDC) is 9.7.
Constant Shoulder Score a.k.a. Constant Score or Constant-Murley Score
The Constant Shoulder Score is scored from 0-100 based on pain, ADLs, ROM, and power. It is appropriate for patients aged 14-85 years. Administration takes 10-15 minutes and scoring takes 2 minutes.
Disabilities of the Arm, Shoulder and Hand (DASH) Outcome Measure
The DASH is a 30 item questionnaire that is scored from 100 to 0 based on physical function, symptoms, and social function. It is recommended for patients aged 18-65 years. Administration takes 5-7 minutes and scoring takes 3 minutes. The MCID is 10.2 and the MDC is 12.
UCLA Shoulder Rating Scale
While the UCLA Shoulder Rating Scale has not been validated in patients with total shoulder replacement, it was originally developed for this patient population. It is scored from 0-35 based on pain, function, forward flexion, forward flexion strength, and overall satisfaction.
Physical Therapy Management of Total Shoulder Replacement
Additional Web Sources
Physio-Pedia.com
Cleveland Clinic.org
Zimmer.co.uk
Surgical Procedure: shoulderdoc.co.uk
Rehabilitation Protocol: Peninsulaorth.com
