Suture anchor fixation of bony Bankart fractures: comparison of single-point with double-point "suture bridge" technique.

BACKGROUND

As an alternative to the standard single-point suture-anchor technique, a suture-bridge technique has been described for the treatment of bony Bankart fractures. There is, however, little evidence supporting one technique over the other. Purpose/

HYPOTHESIS: To compare the failure strength, fixation stability, and loading mechanics of the 2 techniques for the fixation of bony Bankart fractures. We hypothesized that use of the double-point suture-bridge technique would result in superior strength and fixation stability because of the increased compression and contact area between the bony fragment and glenoid fracture site.

STUDY

DESIGN

Controlled laboratory study.

METHODS

A total of 16 shoulders (8 pairs) were tested with an intact glenoid, after creation of a 15% bony Bankart fracture, and after fragment fixation using a single-point or suture-bridge technique. Paired specimens were randomly assigned to each technique. Cyclic progressive loading was applied via a materials testing machine to the glenoid concentrically and eccentrically according to a staircase protocol. Failure strength, fragment displacement, glenoid strain load transfer, and contact area were quantified.

RESULTS

No significant differences in failure strength were found between the single-point and suture-bridge techniques (mean strength, 74 ± 28 N vs 77 ± 56 N, respectively; P = .91). Additionally, no significant differences were found for glenoid load transfer (P ≥ .318) and glenohumeral joint contact (P = .357) between the 2 techniques. Centralized loading, however, produced significant differences in fragment displacement at 5, 150, and 200 N (P ≤ .045), with the single-point technique permitting greater fragment displacement in all cases (0.06-0.28 mm). Similarly, eccentric loading caused significantly greater fragment displacement with the single-point technique at ≥25 N compared with the suture-bridge technique (mean range, 0.38-0.63 mm vs 0.14-0.19 mm, respectively; .009 ≤ P ≤ .048).

CONCLUSION

Single-point and suture-bridge techniques for the fixation of bony Bankart fragments have equivalent failure strengths and load transfers. The suture-bridge technique does provide statistically greater initial fracture fragment stability; however, the clinical implications of this are presently unknown.

CLINICAL RELEVANCE: This study will aid in the selection of the optimal repair technique for bony Bankart fractures by providing important insights into the quality of initial fixation and ultimate strength.