Shoulder arthrodesis is end-stage salvage joint fusion surgery for a joint that has failed, is about to fail or a painful joint that cannot be reconstructed.
The term shoulder arthrodesis is used for fusion of the glenohumeral joint.
Though the indications for arthrodesis are diminishing, it is still an important method of shoulder management. It provides restoration of pain-free function to the shoulder with loss of movements at the joint.
Indications for Shoulder Arthrodesis
The goal of shoulder arthrodesis is to provide a stable base for the upper extremity optimizing hand and elbow function. It is indicated in the following conditions
Paralysis of shoulder for any reason is an indication for arthrodesis. Brachial plexus injuries are a common indication [Earlier paralysis following polio dominated this].
With severe proximal root and upper trunk brachial plexus injuries, the shoulder is paralyzed but there is a good function in the elbow and hand.
If scapular muscles [especially trapezius, levator scapulae, and serratus anterior] have adequate power, arthrodesis of shoulder allows effective functioning of upper limb.
In some cases, the patient might develop inferior subluxation due to the weight of the hanging limb resulting in severe aches, forcing the continued use of the sling. Shoulder fusion may relieve the pain.
A tumor in shoulder or vicinity may necessitate removal of a large amount of soft tissue including rotator cuff or deltoid rendering the shoulder unstable. Arthrodesis is required in such cases.
Failed Shoulder Replacement
Arthrodesis is the reasonable alternative to painful joint following failed replacement following infection, fibrosis, loose implant
Unstable shoulder, if persistently problem needs to be stabilized with arthrodesis.
Most of malunion of the shoulder are well tolerated but sometimes arthrodesis may serve better.
Flail Shoulder and Elbow
Elbow flexorplasty in the presence of a flail shoulder fails to bring the optimum results. Shoulder fusion in combination with flexorplasty provides a more useful arm.
Infectious arthritis especially tubercular arthritis was a common indication for this surgery in the past and though decreased, it still is.
Pyogenic arthritis is rarer but can destroy the joint.
The trend now is to replace the shoulder rather than arthrodesis after the infection has been controlled and quiescent.
Arthroplasty may be considered when the infective episode may have happened years before. In other patients, therefore, arthrodesis can provide the most satisfactory alternative.
Complications of Shoulder Arthrodesis
- Prominent hardware
- Humeral shaft fracture
Contraindications of Shoulder Arthrodesis
It is advisable to immobilize the shoulder in shoulder spica before surgery to make patient get acclimatized before surgery.
- Patients who would not be able to cooperate to rehabilitation after surgery
- Inability to wear a shoulder spica
- Skin problems
- Progressive neurologic disorders.
- Weak trapezius, levator scapulae and serratus anterior
- Ipsilateral elbow arthrodesis
- Contralateral shoulder arthrodesis
- Lack of functional scapulothoracic motion
- Trapezius, levator scapulae, or serratus anterior paralysis
- Charcot arthropathy during the acute inflammatory stage
- Elderly patients
- Progressive neurologic disease
Position of Limb for Shoulder Arthrodesis
Classically recommended position is the salute position but is associated with the unnecessary degree of abduction and forward flexion.
Lowering of arm in this position causes fixed winging of the scapula, causing an uncomfortable strain on the scapulothoracic muscles.
Rowe and Zarins modification of salute position is commonly accepted position for shoulder arthrodesis now. In this, the shoulder should have abduction to clear the axilla, enough internal rotation to reach the midline of the body, both anteriorly and posteriorly; and enough forward flexion to reach the face and head.
Generally speaking, the rule of 30-30-30 is followed with an aim to allow patients to reach their mouths for feeding and back pockets and also elevate arm well over the head.
The positioning of the limb is done as follows
- 20°-30° of abduction
- 20°-30° of forward flexion
- 20°-30° of internal rotation
Technique of Shoulder Arthrodesis
The patient is placed in the sitting position, and the arm is draped separately.
The incision extends from the spine of the scapula to the anterior acromion and down the anterior aspect of the shaft of the humerus.
The deltoid is detached from the anterior acromion, and the rotator cuff is resected. After exposure, the undersurfaces of the acromion, the glenoid fossa, and the humeral head are decorticated [cartilage layer along with subchondral bone is removed].
Glenoid fusion with humeral head has a small contact area. Therefore, the humeral head is subluxated upwards to contact with acromion as well.
The fixation is done by 4.5-mm contoured pelvic reconstruction plate while a desirable position is maintained.
The plate runs along the spine of the scapula over the acromion and down on to the shaft of the humerus. Firstly, three screws are passed through the plate, passing through the humeral head into the glenoid fossa are inserted to compress the arthrodesis site.
Next screw is from the spine of the scapula into the base of the coracoid process and the remaining screws are put.
A bivlaved spica is applied.
Otherwise, a fixed abduction shoulder brace can be used.
If the bone stock is particularly good, screws alone may be used
Postoperatively, after stitch removal at two weeks, cast may be changed as well.
The cast is usually kept till 8 weeks, after which limb is placed in a sling.
Fusion takes about 4 months to unite, on an average.
Complications of Shoulder Arthrodesis
- Malposition [hyperabduction, excessive internal rotation]
- Hardware prominence
- Humeral fractures
- Fracture of the Humerus
- Insufficient Range of Motion