Anterior Glenoid Rim Fracture Following Use of Resorbable Devices for Glenohumeral Stabilization

Abstract

BackgroundResorbable anchors are widely used in arthroscopic stabilization of the shoulder as a means of soft tissue fixation to bone. Their function is to ensure repair stability until they are replaced by host tissue. Complications include inflammatory soft tissue reactions, cyst formation, screw fragmentation in the joint, osteolytic reactions, and enhanced glenoid rim susceptibility to fracture.PurposeTo evaluate resorption of biodegradable screws and determine whether they induce formation of areas with poor bone strength that may lead to glenoid rim fracture even with minor trauma.Study DesignCase series; Level of evidence, 4.MethodsThis study evaluated 12 patients with anterior shoulder instability who had undergone arthroscopic stabilization with the Bankart technique and various resorbable anchors and subsequently experienced redislocation. The maximum interval between arthroscopic stabilization and the new dislocation was 52 months (mean, 22.16 months; range, 12-52 months). The mean patient age was 31.6 years (range, 17-61 years). The persistence or resorption of anchor holes; the number, area, and volume of osteolytic lesions; and glenoid erosion/fracture were assessed using computed tomography scans taken after redislocation occurred.ResultsComplete screw resorption was never documented. Osteolytic lesions were found at all sites (mean diameter, 5.64 mm; mean depth, 8.09 mm; mean area, 0.342 cm2; mean volume, 0.345 cm3), and all exceeded anchor size. Anterior glenoid rim fracture was seen in 9 patients, even without high-energy traumas (75% of all recurrences).ConclusionArthroscopic stabilization with resorbable devices is a highly reliable procedure that is, however, not devoid of complications. In all 12 patients, none of the different implanted anchors had degraded completely, even in patients with longer follow-up, and all induced formation of osteolytic areas. Such reaction may lead to anterior glenoid rim fracture according to the literature and as found in 75% of the study patients with local osteolysis (9/12). Reducing anchor number and/or size may reduce the risk of osteolytic areas and anterior glenoid rim fracture.

Postoperative Recurrence of Instability Due to New Anterior Glenoid Rim Fractures After Arthroscopic Bankart Repair

“…Combining these reports with our findings, 1,2,8,17 it has been clarified that postoperative fractures are not limited to contact athletes, although heavy trauma is risky in contact athletes. Second, cyst formation around degrading bioabsorbable implants and also placing multiple anchors in a linear arrangement might lead to fragility of the glenoid fossa.…”

“…Banerjee et al 2 reported fractures in 3 professional rugby players and stated that resorption defects resulting from absorbable suture anchors contributed to an increased risk of glenoid rim fractures. Augusti et al 1 investigated 12 patients with redislocations at a mean of 22.16 months (range, 12-52 months) after arthroscopic stabilization and found anterior glenoid rim fractures in 9 of them (including 6 professional athletes) even without high-energy trauma. Only 2 or 3 anchors were used in these patients, but osteolytic lesions were found at all anchor sites, and the fracture line passed through the osteolytic lesions.…”

“…3,4,10-12,15,19,21 After postoperative recurrence of instability, we sometimes detect a new fracture of the anterior glenoid rim on computed tomography (CT) that was not recognized preoperatively. As far as we could determine, there have been only 2 previous reports on a large series 1,17 and 2 case reports 2,8 regarding new glenoid rim fractures after arthroscopic Bankart repair. Among these 4 reports, the authors of 1 study used several types of suture anchors, including nonabsorable suture anchors, while the authors of the other 3 studies used absorbable suture anchors.…”

Editorial Commentary: Is Arthroscopic Bankart Repair Using Suture Anchors on the Glenoid Appropriate Treatment for Traumatic Anterior Shoulder Instability?

“…Take et al 16 reported enlargement of the drill holes after using a biodegradable suture anchor, but most of the previous reports other than ours have been about fracture after Bankart repair with absorbable suture anchors, and it has been suggested that fracture is induced by osteolytic changes around the anchors. 4,[6][7][8][9] On the other hand, we found that glenoid rim fractures were still frequent irrespective of whether we used screw-in metal suture anchors or suture-based soft anchors. 3 Although slight enlargement of the anchor holes was also detected in our patients and the possibility of glenoid fracture due to such enlargement cannot be denied, fracture also occurs in shoulders without anchor hole enlargement, suggesting the need for further investigation of factors other than osteolysis.…”

“…Because few of the previous reports were based on large series, 3,4,6-9 their review did not investigate many patients. However, the frequency of postage-stamp fractures was very high among patients with postoperative recurrence of anterior instability (35.1%-75.0%), 3,6,9 suggesting that these fractures are a major factor in recurrence. Even so, this type of fracture has not been recognized in the past, possibly because the causes of recurrent instability were not investigated using CT.…”