Summary
Shoulder replacement has its origins in France in 1893. Since then, there have been many advances in the implant and technique for shoulder arthroplasty. It has been estimated that the demand for total shoulder replacement will increase by 755% between 2011 and 2030. 1
16 Total Shoulder Arthroplasty
I. Indications
Osteoarthritis
Rheumatoid arthritis
Avascular necrosis
Posttraumatic arthritis
Postinstability arthropathy
Pain that has failed to respond to conservative measures
Functional decline that is unacceptable to the patient
Postinfectious arthropathy. 2
II. Contraindications
Absolute:
Active infection.
Relative:
Rotator cuff (RTC)/deltoid dysfunction
Irreparable tear, paralysis, and other previous injury
Previous surgery involving take down/repair of the subscapularis.
Neuropathic joint:
Charcot and syringomyelia.
Severe brachial plexopathy
Approach those with prior infection cautiously
Intractable instability.
III. Presentation/Evaluation
Insidious onset of pain, which is slowly progressive
Progressive stiffness
Functional limitations:
Activities of daily living (ADLs)
Hobbies.
Medical problems
For those with avascular necrosis (AVN):
Attempt to determine the cause
Evaluate other joints.
IV. Physical examination (PE)
Range of motion (ROM):
Active and passive
Osteoarthritis (OA) and AVN:
Global motion loss, particularly external rotation (ER).
RTC strength:
Can be difficult to ascertain due to pain.
Cervical examination
Neurovascular examination
Pain localization
Evaluate for instability
Scapulothoracic motion and lag signs
V. Imaging
Plain radiographs are most important:
Anteroposterior (AP):
Inferior osteophytes
Humeral canal diameter
Acromiohumeral distance:
Less than 6 mm strongly suggestive of RTC tear.
Axillary:
Glenoid version
Glenoid wear
Posterior subluxation.
Definitive assessment of glenoid version and bone stock:
Can glenoid be resurfaced?
Medialization of the glenoid past the coracoid → Don’t resurface the glenoid.
Treat 15-degree posterior glenoid wear with anterior glenoid reaming 50% change of a successful correction 3
Bone graft needed?
Walch classification. 4
Magnetic resonance imaging (MRI):
Can be used if RTC tear is suspected:
Uncommon with OA
RTC tear of 5 to 10% at the time of total shoulder arthroplasty.
May be used if acromiohumeral distance decreased or in case of prior cuff surgery
Also used to stage AVN.
VI. Approach
Deltopectoral:
Uses the deltopectoral interval
Provides excellent exposure for the proximal humerus
Detach subscapularis and anterior capsule:
Lesser tuberosity osteotomy (LTO) versus peel versus tenotomy
No current evidence that one approach is significantly better than another.
Need to do capsular releases for glenoid exposure
Risks:
Axillary nerve
Cephalic vein.
Superior:
Splits the deltoid
Excellent humeral exposure
Using this approach may decrease instability as the subscapularis is not violated 5
Risks:
Glenoid component malpositioning
Axillary nerve injury.
Technical considerations:
Glenoid component: Pegged versus keeled, cemented, metal backed:
Avoid use of metal-backed glenoid components as they have high failure rate
Lower incidence of radiolucent lines in pegged design
It is not known if there is any clinical difference in the implant designs.
Humeral stem can be cemented, cementless, or stemless:
Position in 25 to 45 degrees retroversion
Top of the humeral head shoulder be 5 to 8 mm above the greater tuberosity.
Want to recreate anatomy:
Challenges include glenoid wear, especially posterior, increased glenoid retroversion, and limited bone stock.
Avoid over resection of the humeral head.
Avoid iatrogenic RTC injury during humeral head osteotomy
Postoperative rehabilitation should focus on minimizing tension on the subscapularis repair:
Focus on passive range of motion and active assist range of motion, limiting passive external rotation.