Revising the failed anatomic total shoulder to a hemiarthroplasty

The authors of Revision of Total Shoulder Arthroplasty to Hemiarthroplasty: Results at Mean Five-Year Follow Up observe that while there is a trend to manage failed anatomic total shoulder arthroplasties (aTSA) with revision to a reverse total shoulder arthroplasty (RSA), such revisions can be complicated by difficulties in baseplate fixation, humeral fractures, instability, and acromial stress fractures. In some patients, deficient glenoid bone stock from glenoid component loosening and removal makes conversion to reverse arthroplasty challenging and risks postoperative baseplate loosening.

As an alternative, some cases of symptomatic glenoid loosining after aTSA can be effectively revised using a hemiarthroplasty (HA): removing the glenoid component and replacing the humeral head prosthesis to an implant that best fits within the remaining bony concavity (see examples below).





They studied twenty-nine patients who underwent a single stage conversion from aTSA to HA with mean follow-up of 4.5 years. 26 (90%) shoulders had glenoid component loosening, 8 (28%) had humeral component loosening, and 5 (17%) had both.

The subscapularis was found to be torn in 9 (30%), and the superior or posterosuperior cuff to be torn in 3 (10%).

Pain improved in 25 of 30 patients (87%); mean pain scores improved from 6.2 to 3.1.

Mean Simple Shoulder Test (SST) scores improved from 4.1 to 7.3;

18 of 29 patients (62%) had improvement above the SST MCID threshold of 2.4

22 of 29 (76%) of patients were satisfied with the procedure.

Revision surgery was required in 7 of 29 (24%) of patients. Two had reimplantation of anatomic polyethylene component, two had revision to reverse arthroplasty, and three patients had a revision hemiarthroplasty with complete single stage exchange for continued pain and stiffness.

Fifty-nine percent of patients (17 of 29) had ≥2 positive cultures with the same bacteria. Of these, 14 patients had ≥2 Cutibacterium cultures, 4 had ≥2 coagulase negative Staphylococcus (CoNS) cultures, and 1 had ≥2 cultures for both bacteria. Of the 8 patients that had humeral component loosening, 7 (88%) had 2 or more positive cultures with the same bacteria – 5 with Cutibacterium and 3 with CoNS.
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Comment: As pointed out in a prior post, Managing the loose glenoid component after anatomic total shoulder arthroplasty, failed anatomic shoulder arthroplasty may be managed non operatively, by glenoid component removal and humeral head exchange, by reimplantation of an anatomic glenoid component, or by reverse total shoulder arthroplasty.

How might we consider these options?

The advantages of conversion of a failed anatomic total shoulder to a hemiathroplasty lie in 

(1) avoiding the catastrophic glenoid component failure that could occur with conversion to a reverse total shoulder arthroplasty, 

(2) avoiding the risks of dislocation and acromial/spine fractures with reverse total shoulder

(3) potentially avoiding the fracture risk associated with removal of the humeral component

If the hemiarthroplasty fails to yield satisfactory comfort and function, consideration can be given to re-revision to an anatomic or reverse total shoulder.

On the other hand, if glenoid failure is accompanied by failure of the rotator cuff, consideration should be given to reverse total shoulder as the first revision (among the 6 patients who underwent conversion from aTSA to HA with cuff failure, only 3 (50%) attained MCID improvement of SST and only 3 (50%) were satisfied with the results of their revision).

If glenoid failure is associated with humeral component loosening, this and prior studies report a very high rate (88%) of multiple positive deep cultures. In such a situation, harvesting multiple deep specimens for culture, humeral and glenoid component removal, thorough debridement, topical antibiotics and a course of postoperative antibiotics should be considered.

Of course prevention of total shoulder failure is better than trying to treat it. (see The glenoid component in total shoulder arthroplasty: getting it done right).

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Here are some videos that are of shoulder interest
Shoulder arthritis - what you need to know (see this link).
How to x-ray the shoulder (see this link).
The ream and run procedure (see this link).
The total shoulder arthroplasty (see this link).
The cuff tear arthropathy arthroplasty (see this link).
The reverse total shoulder arthroplasty (see this link).
The smooth and move procedure for irreparable rotator cuff tears (see this link).
Shoulder rehabilitation exercises (see this link).