Massive acromioclavicular ganglionic cyst treated with excision and allograft patch of acromioclavicular region.

Although acromioclavicular (AC) joint cysts are infrequent, when they do occur they are typically associated with full-thickness rotator cuff tears or AC joint degeneration, or both. AC joint cysts are also typically benign, being either ganglionic or synovial. Few reports have described the surgical management of massive AC ganglionic cysts. Some of these reports have advocated repairing the underlying rotator cuff tear because the recurrence rate of AC joint cysts might otherwise be high, regardless of whether they are ganglionic or synovial. However, humeral hemiarthroplasty or AC resection without hemiarthroplasty have been reported as being effective at reducing AC joint cyst recurrence when rotator cuff tear repair is not possible. We present a case of an elderly patient in frail health who presented with a massive ganglionic cyst of the AC joint that was associated with end-stage rotator cuff-tear arthropathy. Excision of the cyst was recommended only after skin compromise or fistula formation was imminent. The rotator cuff tear could not be repaired, and no attempt was made to implant a glenohumeral endoprosthesis; this decision was influenced by the patient’s tenuous cardiac status. The novel aspects of the treatment of this case include (1) an allograft patch, which was used to seal the surfaces of the resected bones and the base and margins of the remaining AC joint ligaments, and (2) the anterior deltoid was advanced to augment the excision site.