Glenoid Bone-grafting with Reverse total shoulder procedures

[mtomaino]

The Reverse shoulder implant has revolutionized the treatment of rotator cuff arthropathy and failed rotator cuff repair---leveraging the power of the functioning deltoid muscle to provide overhead function by constraining the "ball and socket", and increasing the moment arm of the muscle via its design attributes. What is a bit more controversial, in some corners, is the role of the Reverse shoulder as a revision procedure for a failed conventional shoulder replacement---either total or partial, particularly when a bony defect exists in the glenoid (socket). This might develop over time from wear, or as a consequence of implant removal.
A recent study from the Mayo Clinic reveals, however, that the results of glenoid bone-grafting, while not perfect, may be within a reasonable risk profile for most, especially when considering the potential benefit of at least modest pain relief and functional restoration. Published in the Journal of Bone and Joint Surgery (JBJS) Oct 2015, Drs Cofield et al report the results of 143 consecutive reverse shoulder replacements performed as revision---in which 41 (29%) required bone-grafting. The 102 patients who did not require a bone-graft served as the control group. The 2 and 7 year survival rate free from revision was 88% and 77% for shoulders where a bone-graft was needed, which was actually lower than the control group. There was no evidence of glenoid loosening at 2 and 5 years in 92% and 89% of bone-grafted shoulders, which was worse than shoulders that did not require a bone-graft. Only 4 patients out of the 41 needing a bone graft required a revision for loosening (10 %). And----patients uniformly enjoyed better pain range of motion, decreased pain relief and higher levels of satisfaction compared to before revision surgery.
What is not entirely clear from the study is whether allograft or autograft, is better or whether a structural graft as opposed to cancellous may withstand loosening more reliably. Again--only 10% required a revision for loosening. The study suggested that a design with a lateral offset may result in a higher rate of loosening but given the numbers this is arguably speculative.

The point of this study, and the reason I note its results is that Reverse replacement clearly has a role in the treatment of shoulder pain and loss of function, glenoid bone loss notwithstanding---whether in the setting of a failed total replacement that requires revision, or due to erosive wear from arthritis or dysplasia. The various baseplate options on the market differ in terms of offset, fixation options, augmentation, and surgical techniques may vary when dealing with bone defects-- such as off axis reaming and the use of an augmented baseplate, versus baseplate center screw placement along an alternative (scapular spine) centerline. Given the modest requirements for "improved function" in many such cases-----pain relief and the ability to raise one's arm to the horizon may make consideration of a Reverse quite reasonable so long as patient expectations are in sync.