New frontiers in arthroscopic treatment of glenohumeral instability

Magnetic resonance arthrography for assessing severity of glenohumeral labroligamentous lesions

PURPOSE

To compare magnetic resonance (MR) arthrography and arthroscopy as a means of assessing the severity of labral tear in anterior glenohumeral instability.

METHODS

52 patients presenting with traumatic recurrent anterior shoulder instability were evaluated using MR arthrography; 30 shoulders with a labroligamentous lesion were treated with arthroscopic Bankart repair. Their MR arthrographic images were interpreted by 3 senior musculoskeletal radiologists, and a radiological diagnosis was reached by consensus. The sensitivity and positive predictive values of MR arthrography for detecting a labral tear were determined. Agreement between MR arthrography and arthroscopy in terms of the width and depth of the labral tear was analysed.

RESULTS

On arthroscopy, a labroligamentous lesion (Bankart lesion and its variants) was present in all the 30 shoulders. Agreement between the MR arthrography and arthroscopy in terms of the width and depth of the labral tears was good.

CONCLUSION

MR arthrography is an accurate means of assessing the severity of anterior labroligamentous lesions and yields a good correlation with arthroscopy.

FUNCTIONAL ASSESSMENT OF ARTHROSCOPIC REPAIR FOR RECURRENT ANTERIOR SHOULDER INSTABILITY

Objective: To clinically and radiologically evaluate patients who underwent arthroscopic surgical treatment for anterior shoulder instability by means of the Bankart technique, using metal anchors. Methods: This was a retrospective study on 49 patients who underwent arthroscopic repair of anterior shoulder instability between 2002 and 2007. The patients were evaluated using the Carter-Rowe score and the Samilson and Prieto classification. The mean age at the time of surgery was 30 years. The mean length of follow-up was 42.7 months (ranging from 18 to 74). 85% of the patients were male. Results: The mean Carter-Rowe score was 83 points (ranging from 30 to 100) including 31 excellent results, 7 good, 3 fair and 8 poor. Recurrent dislocation was observed in 16% (8 patients), and 37.5% of them were of traumatic origin. Joint degeneration was present in 32.5% of the cases, including 5 cases of grade 1, 6 cases of grade 2 and 2 cases of grade 3. The average loss of external rotation was 12° and the loss of anterior elevation was 8°. There was a statistically significant relationship (p < 0.05) between arthritis and age at first dislocation, age at surgery and crackling. 92% of the patients reported high degrees of satisfaction after the procedure. Among the complications, there were two cases of stiff shoulder, one patient with prominence of the synthesis material and one case of anchor loosening. Conclusion: Arthroscopic repair of anterior shoulder instability using metal anchors was shown to be effective, with a low complication rate.

Cyclic loading comparison of Bio-SutureTak-#2 FiberWire and Bio Mini-Revo-#2 Hi-Fi suture anchor-sutures in cadaveric scapulae

This study compared tap-in Bio-SutureTak suture anchor-#2 FiberWire suture (Group 1) and screw-in Bio Mini-Revo suture anchor-#2 Hi-Fi suture (Group 2) fixation in the glenoid region of interest for Bankart repair, in addition to evaluation of isolated suture loop biomechanical properties under progressive incremental cyclic loads. With knowledge of glenoid apparent bone mineral density (BMD), implant preparation and fit characteristics, and following application of a light manual tensile load, the primary investigator scored each specimen for perceived within group biomechanical test performance using a 0-10 point modified visual analog scale. After scoring, 12 paired constructs were placed in a servo hydraulic device clamp, preloaded to 25 N, and cycled between 25 and 50 Hz with a 25 N load increase every 25 cycles. Group 2 withstood greater load (104.1 +/- 56 vs. 70 +/- 36.9 N, P = 0.04) and displaced more at failure (13 +/- 4.5 vs. 8.6 +/- 3.3 mm, P = 0.04). All Group 1 specimens failed prior to reaching 150 N, whereas 25% of Group 2 specimens (n = 3) failed at 200 N. All specimens failed by anchor pullout except for three Group 2 specimens that failed by eyelet breakage at 200 N. Isolated suture testing revealed that Group 1 sutures displaced less at each cyclic load (P = 0.028) and withstood greater failure loads (P = 0.028) than that of Group 2 sutures. Group 2 constructs displayed moderately strong relationships between perceived within group biomechanical test performance and ultimate load (r (2) = 0.55) and displacement at failure (r (2) = 0.67). Group 1 did not display significant relationships. Similar biomechanical performance between 50 and 125 N, greater load at failure, and superior biomechanical test prediction accuracy suggest that the screw-in type Bio Mini-Revo suture anchor-#2 Hi-Fi suture combination may be preferred for Bankart lesion repair in low apparent BMD glenoid processes. The #2 Hi-Fi suture, however, allowed significantly greater displacement than the #2 FiberWire suture at each progressive cyclic load interval.