Perianchor radiolucency after knotless anchor repair for shoulder instability: correlation with clinical results of 69 cases.

Background: Although there would seem to be a logical relationship between radiolucency around the suture anchor and clinical result in Bankart repair, the correlation has not been demonstrated so far.

Hypothesis: Knotless suture anchor is a viable alternative for arthroscopic Bankart repair, but postoperative radiologic findings of radiolucency around anchors are correlated with poor clinical results.

Study Design: Case series; Level of evidence, 4.

Methods: Sixty-nine consecutive patients with Bankart lesions were treated with arthroscopic reconstruction using knotless metal suture anchors. The mean follow-up was 40 months. Clinical and radiologic analysis was performed retrospectively. A new concept of perianchor radiolucency was introduced and, according to this radiologic finding, patients were divided into 2 subgroups: the perianchor radiolucency group and those who did not reveal perianchor radiolucency. The perianchor radiolucency group was further subdivided by shape and location. "Root type" was defined as a radiolucent halo at the root of the anchor, and perianchor radiolucency without any root halo was named "branch type." Location of perianchor radiolucency was described as above or below the equator of the glenoid.

Results: After operation, the mean Rowe score increased to 93.8 from 43.1, and computed tomography arthrogram showed a 97% healing rate. Reoperations were performed due to 1 case of redislocation and 2 cases of anchor arthropathy. All these reoperated cases revealed perianchor radiolucency before reoperation. Other than reoperated cases, 2 patients showed apprehension at final evaluation. The perianchor radiolucency group had a significantly lower Rowe scores than the group that showed no perianchor radiolucency. Some of the patients in the perianchor radiolucency group had peculiar radiologic findings frequently associated with complications. The radiologic findings that consisted of root-type perianchor radiolucency located below the equator of the glenoid was termed the "ominous sign." Osteophytes of the humeral head together with the ominous sign is considered a warning sign of forthcoming progression of anchor arthropathy, and the authors suggest early surgical intervention with these findings.

Conclusion: After Bankart repair using knotless suture anchor, the ominous sign might be an important warning sign for possible forthcoming complications including redislocation, anchor arthropathy, and residual instability.