by Patrick Smith
Reverse total shoulder arthroplasty is a joint replacement procedure where the ball and socket articulations of the glenohumeral joint are reversed. In this procedure, a polyethylene socket is placed in the proximal humerus while a hemispherical articulating ball is placed in the glenoid fossa of the scapula.1 The aim of this procedure is to restore glenohumeral joint function. Recently, the reverse total shoulder arthroplasty is becoming a popular technique used to treat end stage rotator cuff arthropathy, and the indications for this procedure continue to increase .1
The glenohumeral joint is a ball and socket joint consisting of the humeral head (ball) and the glenoid fossa (socket). The primary movers of the joint are the rotator cuff (supraspinatous, infraspinatous, subscapularis, and teres minor), teres major, deltoid, biceps brachii and triceps brachii, latissimus dorsi and pectoralis major and minor. Stability of the joint is provided by both active and passive supports. Active supports of the glenohumeral joint are the rotator cuff muscles. The joint capsule, ligaments, and the labrum provide passive support. Ligamentous support is provided mainly by the superior glenohumeral, middle glenohumeral, and inferior glenohumeral ligaments. The anterior and posterior bands of the coracohumeral ligament also provide passive stability of this joint.2 The labrum acts to deepen the socket of the glenoid fossa, increasing passive support.
Originally, the reverse total shoulder arthroplasty was created to repair end stage rotator cuff arthropathy.4 Rotator cuff arthropathy is a shoulder pathology characterized by rotator cuff insufficiency, superior migration of the humeral head, and arthritic changes in the glenohumeral joint.5 Reverse total shoulder arthroplasty is also indicated in various other pathologies, including complete or severe tear of the rotator cuff, proximal humerus fracture, nonunion, malunion, previous failed shoulder arthroplasties, glenohumeral instability, glenohumeral pseudoparalysis without arthritis, post-traumatic arthritis, or even reconstruction after tumor resection.4,6
Post surgical presentation varies according to pre-surgery status as well as the surgical procedure itself. Post surgical range of motion varies according to residual soft tissue tension, residual muscle function, and the motion that is available with the prosthetic components used.7 Range of motion achievable prior to surgery may also play a role in the potential range of motion post-surgery. Functional active range of motion as compared to the uninvolved side is achievable. Instability leading to dislocation has been reported in the prosthetic joint.7 Post surgical strength potential relies on which muscles remain intact after surgery. External rotator strength may not be returned after surgery, especially when the external rotator strength was low or negligible prior to surgery. Reverse total shoulder patients report a significant pain decrease as compared to their pre-surgical pain levels.6
There are a variety of etiologies for reverse total shoulder replacement. A few common etiologies are:
1. Rotator Cuff Tear8:
- Acute tears: Fall on outstretched arm, attempting to lift something too heavy with poor mechanics
- Degenerative tears: Repetitive shoulder motions which stress rotator cuff muscles (sporting activities, job activities, housework), lack of blood supply to rotator cuff tendons, bone spurs
2. Rotator Cuff Arthropathy 9:
- Permanent loss of rotator cuff tendons and arthritic changes in the glenohumeral joint.
3. Proximal Humerus Fracture10:
- Direct blow to the proximal humerus due to a fall, collision, or road traffic accident
4. Previous Failed Shoulder Arthroplasties11:
- From most common to least common:
- Component loosening, instability of the glenohumeral joint, rotator cuff tear, fracture around the prosthesis, infection, implant failure, and deltoid dysfunction
- Traumatic incident, atraumatic, glenoid dysplasia, Ehlers-Danlos syndrome
1. Epiphysis: Upper part of the prosthetic humeral stem. It is a metal component that lies even with the proximal humerus
2. Diaphysis: Lower portion of the humeral stem. It is inserted down into the shaft of the humerus
3. Polyethylene Cup: This becomes the socket of the new ball and socket joint. It is made of polyethylene and is attached to the epiphysis proximally.
1. Metaglene: Specially coated metal plate that is attached to the glenoid fossa with screws.
2. Glenosphere: A half globe metal piece that is attached to the metaglene. The glenosphere becomes the ball part of the new glenohumeral joint.
*This is an example of one surgical approach to the reverse total shoulder arthroplasty. Surgeons may differ in their surgical protocols.
An incision will be made to suit the surgical needs of the patient. Often, a deltopectoral approach is used for this procedure. The incision is superior and medial to the coracoid process, and extends to the deltoid tuberosity on the humerus. However, a transacromial or a superolateral approach may also be used.15 The deltoid muscle is freed from any adhesions to the surrounding tissue and is moved via blunt dissection to allow access to the glenohumeral joint. The axillary nerve is found and spared. The insertion of the subscapularis tendon is removed from the lesser tubercle of the humerus while keeping the origin intact. The humerus is then externally rotated to dislocate the humerus from the glenoid fossa. The humeral head is cut and removed. The medullary canal is reamed to the appropriate length for insertion of the diaphysis (lower humeral stem) to be placed. The proximal humerus is then contoured to the desired shape.
The humerus is then moved to allow access to the glenoid fossa. The labrum is removed and the capsule is released. A central drill hole is prepared. The glenoid fossa is reamed, the drill hole is enlarged, and the base plate is screwed into the fossa. The glenosphere is screwed into the base plate and the glenoid portion of the replacement is complete.
Cement is placed into the humeral shaft and the diaphysis is placed into the canal in the proper position. The cement is allowed to cure. A trial cup is placed, the joint is reduced, and range of motion is checked. The joint is then dislocated, the trial cup is removed, the polyethylene cup is inserted, the joint is reduced and range of motion is checked again. In about 42% of surgeries the subscapularis tendon is replaced.15
Surgery video: Union Memorial Hospital.
According to the definitions presented by Zumstein15 in his meta-analysis of literature:
- A problem is an intra-operative or post-operative event that is not likely to affect the patient’s final outcome. Problems include hematomas, radiographic scapular notching, and intraoperative dislocation.
- A complication is defined as any intra-operative or post-operative event that is likely to have a negative outcome on patient recovery. Complications include instability, infection, dislocation, nerve palsies, loosening of components or fractures.
With these definitions in mind, Zumstein15 reported a problem rate of 44%, a complication rate of 24%, re-operation rate of 3.5% and a revision rate of 10%.
A very common problem is scapular notching. This notching is due to biomechanical changes of the joint, and subsequent impingement of the humeral component against the neck of the scapula when the arm is adducted. However, scapular notching is rarely clinically significant.
Zumstein15 reports that the populations showing the majority of complications include patients with rheumatoid arthritis and patients who are having a revision surgery. The most common complication has been reported to be instability post-operatively. This instability can potentially be attributed to loss of muscular attachments, particularly when the subscapularis is completely released. Ligament disruption and decreased tension of the deltoid may also contribute to instability post-operatively.
POST OPERATIVE REHABILITATION:
For full rehabilitation protocol, refer to Boudreau16
Early dislocation risk with internal rotation, adduction, and extension.
Phase 1: Immediate Post-Surgical/ Joint Protection (1-6 weeks)
1. Tissue healing
2. Patient education
3. Enhance passive range of motion
4. Independent in ADL, ambulation (as per pre-operative status), and transfers
1. Sling should be worn for 3-6 weeks, and removed for exercise and bathing
2. Avoid shoulder extension, internal rotation, and adduction
3. No active range of motion in surgical shoulder
1. Passive range of motion, forward flexion and elevation in scapular plane to 90 degrees.
2. External rotation to available range of motion.
3. Activity modification
5. Periscapular sub-max pain free isometrics.
6. Active/active assist cervical, elbow, wrist, and hand exercises
1. Continue exercises
2. Sub-max pain free deltoid isometrics in scapular plane
1. Exercise progression
2. Progress passive range of motion forward flexion and elevation to 120 degrees
3. Increase external rotation range of motion as tolerated
Phase 2: Active Range of Motion/Early Strengthening (6-12 weeks)
1. Continue progression of passive range of motion
2. Restore active range of motion
3. Control inflammation
4. Tissue healing
5. Scapular stability
1. No lifting of objects heavier than 2 pounds with surgical shoulder
1. Continue with passive range of motion, incorporate internal rotation (50 degree maximum) in the scapular plane
2. Begin active assist/active range of motion in scapular plane
3. Ice if necessary
4. Scapulothoracic mobilization (grade 1&2).
5. Progress elbow, wrist, hand strength
1. Continue exercises, progress activity
2. Gentle internal and external rotation pain free isometrics
3. Sub-maximal and pain free periscapular and deltoid isotonic strength
4. Progress to internal and external rotation strengthening exercises with light weight or bands
Phase 3: Moderate Strengthening (Weeks 12+)
1. Enhance functional use of surgical extremity
2. Enhance mechanics, endurance, and strength of shoulder joint
1. No lifting of items six pounds or more
1. Continue exercises
2. Progress to resisted flexion and elevation in standing
Phase 4: Home Exercises (4 months and beyond)
1. Continued progression into functional and recreational activities.
ADDITIONAL WEB REFERENCES
1. Sanchez-Sotelo, J. (2009), Reverse total shoulder arthroplasty. Clinical Anatomy, 22: 172–182.
2. Edelson JG, Taitz C, Grishkan A. The coracohumeral ligament. anatomy of a substantial but neglected structure.
J Bone Joint Surg Br. 1991;73(1):150-153.
3. Bontempo NA, Mazzocca AD. Biomechanics and treatment of acromioclavicular and sternoclavicular joint
injuries. Br J Sports Med. 2010;44(5):361-369
4. Drake GN, O'Connor DP, Edwards TB. Indications for reverse total shoulder arthroplasty in rotator cuff disease.
Clin Orthop Relat Res. 2010;468(6):1526-1533. doi: 10.1007/s11999-009-1188-9.
5. Ecklund KJ, Lee TQ, Tibone J, Gupta R. Rotator cuff tear arthropathy. J Am Acad Orthop Surg. 2007;15(6):340-
6. McFarland, EG. Patient guide to “reverse” prosthesis. The Johns Hopkins University Department of Orthopedic
Surgery. http://www.hopkinsortho.org/Pt.%20Guide-reverse%20prosthesis_pks_01-23-06.pdf. Accessed
November 19, 2011.
7. Walker M, Brooks J, Willis M, Frankle M. How reverse shoulder arthroplasty works. Clin Orthop Relat Res.
8. American Academy of Orthopaedic Surgeons. Rotator cuff tears. American Academy of Orthopaedic Surgeons.
http://orthoinfo.aaos.org/topic.cfm?topic=a00064. Accessed November 20, 2011.
9. Warme, WJ, Matson FJ. Minimize Cuff tear arthropathy - CTA - prosthesis for shoulder arthritis: Surgery with a cementless CTA prosthesis can lessen pain and improve function in shoulders with the combination of arthritis and rotator cuff tears. University of Washington Orthopaedics and Sport Medicine. December 23, 2009. Accessed November 18, 2011.
10. American Academy of Orthopaedic Surgeons. Shoulder trauma. American Academy of Orthopaedic Surgeons. http://orthoinfo.aaos.org/topic.cfm?topic=A00394. Accessed November 20, 2011
11. Dines JS, Fealy S, Strauss EJ, et al. Outcomes analysis of revision total shoulder replacement. J Bone Joint
Surg Am. 2006;88(7):1494-1500
12. University of Washington Orthopaedics and Sport Medicine. Types of glenohumeral instability. University of Washington Orthopaedics and Sport Medicine. http://www.orthop.washington.edu/PatientCare/OurServices/ShoulderElbow/Articles/TypesofGlenohumeralInstability.aspx. February 10, 2005. Accessed November 12, 2011.
13. University of Maryland Orthopaedics: Shoulder and Elbow Program. Reverse shoulder replacement surgery. University of Maryland Medical Center. http://www.umm.edu/orthopaedic/rsr.htm. September 20, 2010. Accessed November 15, 2011.
14. Lenarz CJ, Gobezie R. Reverse total shoulder arthroplasty. J Vis Exp. 2011 (53).
15. Zumstein MA, Pinedo M, Old J, Boileau P. Problems, complications, reoperations, and revisions in reverse total shoulder arthroplasty: A systematic review. J Shoulder Elbow Surg. 2011;20(1):146-157.
16. Boudreau S, Boudreau E, Canoa D, Higgins L, Wilcox WB. Reverse total shoulder arthroplasty protocol. Brigham and Women's Hospital. http://www.brighamandwomens.org/Patients_Visitors/pcs/RehabilitationServices/Physical%20Therapy%20Standards%20of%20Care%20and%20Protocols/Shoulder_Reverse_TSA_protocol.pdf. 2011. Accessed November 20, 2011.