Acromioclavicular joint cyst formation

Abstract

Acromioclavicular joint (ACJ) cysts are an uncommon and unusual sequela associated with shoulder pathophysiology. The majority of literature on ACJ cysts consists of individual case reports with no definitive literature review currently available. In addition to a comprehensive literature review, four clinical cases are presented in this report. First described by Craig (1984), a total of 41 cases have been previously reported in the literature. Of these cases, five occurred with the rotator cuff musculature intact. The remaining 36 cases of ACJ cysts occurred in patients with a complete tear/avulsion of the rotator cuff. Previous attempts at compiling a complete record of all reported cases have combined several distinct conditions into a single category. This article presents two distinct etiologies for the pathogenesis of ACJ cyst formation. In the presence of an intact rotator cuff, a Type 1 cyst can form superficially and be limited to the ACJ. Following a massive or traumatic tear of the rotator cuff, mechanical instability of the humeral head can cause a deterioration of the inferior acromioclavicular capsule (cuff tear arthropathy) and an overproduction of synovial fluid. Overtime, a "geyser" of fluid can form between the glenohumeral and the ACJ, forming a Type 2 cyst. This differentiation and categorization is essential for appropriate classification and treatment.

Intratendinous supraspinatus cyst as a cause of shoulder impingement

“…10 Acromioclavicular joint (ACJ) cysts may occur in a degenerative ACJ or in association with rotator cuff tears. 11 To avoid recurrence, a distal clavicle excision can be carried out. 11,12 Intra-articular glenohumeral cysts are extremely rare and have only been reported once in association with a labral tear.…”

“…11 To avoid recurrence, a distal clavicle excision can be carried out. 11,12 Intra-articular glenohumeral cysts are extremely rare and have only been reported once in association with a labral tear. 13 To our knowledge, this is the first reported case of an intratendinous cyst causing mechanical symptoms of impingement, which has responded well to decompression of the cyst.…”

Acromioclavicular joint cyst formation in a patient with rotator cuff-tear arthropathy: a rare cause of shoulder discomfort

“…A distinction of two possible aetiologies and consequently a categorisation into two subtypes was first proposed by Hiller et al 1. Accordingly, type 1 cysts occur due to a disruption of the subacromial bursa in the setting of a degenerated AC joint allowing fluid to escape and accumulate subcutaneously.…”

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

“…2,11,17,20 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. 11,17 However, humeral hemiarthroplasty 7,8 or AC resection without hemiarthroplasty 8, [16][17][18] have been reported as being effective at reducing AC joint cyst recurrence when rotator cuff tear repair is not possible.…”

“…4,7,8,10,11,[13][14][15][16][17][18][20][21][22] AC joint cysts are also typically benign, being either ganglionic or synovial. Few reports have described the surgical management of massive AC ganglionic cysts.…”