Shoulder Arthroplasty肩关节置换

Indications for Shoulder Arthroplasty
Osteoarthritis Rheumatoid arthritis Rotator cuff tear arthropathy Avascular necrosis Post-traumatic arthritis Severe proximal humeral fractures
Other Problems with Metal-Backed Glenoid Components
Metal-backing increased the thickness of the component and often lead to overstuffing of the joint. To avoid over-stuffing the joint, the polyethylene thiFra Baidu bibliotekkness had to be reduced, resulting in accelerated poly wear & failure
The Need for Modularity
F-H Offset B-C Head thickness D-E = 8mm Top of humeral head is higher than greater tuberosity
The Need for Modularity
Reestablishing normal glenohumeral anatomic relationships is important to ensure optimal results.
Total Shoulder
More consistent pain relief Better fulcrum for active motion
Difficult procedure Longer OR time Poly wear can cause loosening of both components More Glenoid bone loss
Arthroplasty Options
Hemiarthroplasty
Reverse Total Shoulder Total Shoulder
Surgical Approach
Deltopectoral
Coracoid
A little history
1893- French surgeon Pean inserted platinum and rubber components to replace a shoulder joint destroyed by tuberculosis. 1951- Neer I, Vitallium Hemiarthroplasty prosthesis which resulted in pain relief and good function compared to previous options.
Osteoarthritis
In addition to the universal features of osteoarthritic joints (joint space narrowing, cyts, osteophytes…), the shoulder can also demonstrate
to
Contraindications to Shoulder Arthroplasty
Active or recent shoulder joint infection Paralysis with complete loss of rotator cuff and deltoid function A neuropathic arthropathy Irreparable rotator cuff tear is a contraindication to glenoid resurfacing.
Boileau P, Avidor C, J Shoulder Elbow Surg. 2002 Jul-
Aug;11(4):351-9.
40 Shoulders with 3 year follow up. Metal-backed – 2% radiolucent lines, 100% progressive, 25% loose in 3 years. Associated with shift and osteolysis. Cemented – 80% radiolucent lines, 25% progressive. None loose in 3 years.

Recommendation based on Experience
Neer, 1998 “When the articular surface of the glenoid is good, the results of hemiarthroplasty are similar to those of TSA. Wear on the glenoid has not been a problem if the articular surface was good at the time of surgery and glenohumeral motion was re-established”
Shoulder Arthroplasty
Daniel Penello Upper Extremity Rounds April 26, 2006
Lesions of the shoulder requiring arthroplasty are much less common than lesions involving the weightbearing joints of the body, such as the hip and knee.
Recommendations based on Evidence
Gartsman, 2000 51 shoulders Average f/u of 35 months No difference in ASES or UCLA scores. Significantly better pain relief with TSA 3 pts crossed over to TSA by 35 months
Easy procedure Short Operating time Less risk of instability Can be revised to TSA
Less reliable pain relief Progressive Glenoid erosion may cause results to deteriorate over time Need concentric glenoid
The Shoulder
Greatest ROM No inherent bony stability Relies on soft tissues for stability Many injuries involve the soft tissues (rotator cuff, labrum) Little glenoid bone stock
PROX POROUS COATED
Need good bone stock Higher risk of intra-operative fracture Less stressshielding Easier to revise
FULLY POROUS COATED
Need good bone stock Higher risk intra-operative fracture More stress shielding Hard to revise
1974- Neer II Prosthesis. Modified Neer I to conform to a glenoid component.

Courtesy of Smith & Nephew
1970’s - constrained components were popular, but follow-up reports demonstrated high rates of loosening, particularly of the glenoid component.
Iannotti JP; JBJS 74A 1992
Other Anatomic Variables to Consider
Glenoid : 2° anteversion 7° retroversion
Humeral Head: 20° - 40° retroversion Axial CT of the glenohumeral joint is a valuable pre-op planning tool.
1980’s – Modular humeral components were developed, along with cementless glenoid fixation using polyethylene on a metal backing.
Cemented polyethylene versus uncemented metalbacked glenoid components in total shoulder arthroplasty: a prospective, double-blind, randomized study.
Poly-metal disassociation occurred with unacceptable frequency.
Humeral Components
CEMENTED
Good for osteopenic bone Lower risk of intra-operative fracture More stressshielding Hard to revise
Posterior glenoid erosion Flattening of the humeral head Enlargement of the humeral head Rotator cuff tears are uncommon in OA
Hemi


vs
Cemented vs Press-fit Humeral Components
Harris, Jobe and Dai reported less micromotion with proximally-cemented stems. Fully cemented stems provide no additional benefit or stability over proximallycemented stems. Sanchez-Sotelo reported a low rate of stem loosening regardless of fixation, but pressfit prostheses developed more radiolucent lines in the first 4 years.
Recommendations based on Evidence
Kirkley et al, 2000 42 pts, 3 surgeons (stratified) One year follow-up No significant difference in WOSI, ASES, DASH Constant Score or ROM. Trend towards better pain relief with TSA. 2 Hemi patients crossed over to TSA after 1 year follow-up.