Hemiarthroplasty of the Shoulder

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- Discussion:
           - see discussion shoulder arthroplasty
           - considered in young pt w/ OA, posttraumatic disorders (w/ no have glenoid involvement nor erosion), AVN, or massive RTC tear;
           - approximate survival rate at 10 years is about 80%;
           - need for revision is significantly higher in patients who underwent hemiarthoplasty for trauma rather than for RA;
                    - upto one half of younger patients undergoing hemiarthroplasty will have subjective or objective unsatisfactory results;
           - complications unique to shoulder hemiarthroplasty include erosion of the glenoid which may eventually occur in upto 70% of patients;
                    - of patients undergoing revision hemiarthroplasty, the vast majority will be performed for a painful glenoid arthritis;
           - indications / inclusion criteria: (for hemiarthroplasty instead of total shoulder arthroplasty);
                    - concentric glenoid consisting of eburnated bone
                    - humeral head needs to be centered in the glenoid preoperatively or at the time of surgery;
                    - there needs to be less than 25% intraoperative subluxation of the trial humeral component, after soft tissue balancing;
                    - non concentric glenoid: hemiarthroplasty may still be indicated if the glenoid can be converted to a smooth concentric surface w/ reaming;
                    - references:
                           - Treatment of Glenohumeral Arthritis with a Hemiarthroplasty: A Minimum Five-Year Follow-up Outcome Study.

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- Surgical Technique 
    - humeral component preparation and insertion:
    - modular head 
         - note that in choosing a hemiarthroplasty component, it may be useful to select one with a modular head, so that the head can be removed if a
               future glenoid resurfacing procedure is required;
               - if the head is not modular, then the entire stem would have to be removed inorder to achieve the necessary exposure for glenoid arthroplasty;
         - biologic glenoid resurfacing
               - Humeral Hemiarthroplasty with Biologic Resurfacing of the Glenoid for Glenohumeral Arthritis.
               - Nonprosthetic glenoid arthroplasty w/ hemiarthroplasty and TSR yield similar outcomes in management of comparable patients w/ glenohumeral DJD

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- references:
                    - Acute prosthetic replacement for severe fractures of the proximal humerus.
                    - Modular hemiarthroplasty for fractures of the proximal part of the humerus.
                    - Bipolar implant shoulder arthroplasty. Long-term results.
                    - Total shoulder arthroplasty versus hemiarthroplasty. Indications for glenoid resurfacing.
                    - Prosthetic replacement of the proximal humerus.
                    - Glenoid loosening in total shoulder arthroplasty.  JL Franklin et al.  J. Arthroplasty.  Vol 3. 1988. p 39-46.
                    - Bipolar hemiarthroplasty for chronic rotator cuff tear arthropathy
                    - Optimizing the Glenoid Contribution to the Stability of a Humeral Hemiarthroplasty without a Prosthetic Glenoid.

                    - Humeral Head Replacement for the Treatment of Osteoarthritis. 



    













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