The antero-inferior (transmuscular) approach for arthroscopic repair of the bankart lesion: An anatomic and clinical study

Abstract

In order to find a direct approach to the antero-inferior third of the glenoid rim, an anatomic study was performed on a total of 89 shoulders (48 cadavers). To obtain defined reference points for the anterior inferior third of the glenoid cavity, it was compared with the hour markings on a clock face. The 4:30 position on the right shoulder and the 7:30 position on the left shoulder were defined as the relevant reference points. The average distance between the palpable end of the coracoid process and the 4:30 and 7:30 positions was 19 mm. The average distance to the point of intersection of the musculocutaneous nerve with the medial margin of the conjoined tendon was more than 5 cm, and was never less than 2 cm. The average distance of the axillary nerve from the 4:30 position was 2.5 cm in the horizontal plane, with a minimum of 1.5 cm. Radially, the average distance of the axillary nerve was 1.7 cm, with a minimum of 1.3 cm. The anatomic study was followed by a clinical study of 264 patients. An antero-inferior portal located maximium 2 cm distal from the palpable coracoid tip was selected for the introduction of a trocar sheath and blunt trocar, passing through the subscapularis muscle to access the antero-inferior area of the glenoid rim. As additional protection for the musculocutaneous nerve, the direction of the trocar was adjusted during introduction. Reattachment of the labrum-capsule complex was performed extra-articularly. In all cases, at least one implant was located inferior to the 4:30 or 7:30 position. No neurovascular complications arose out of the choice of portal. Out of the 264 patients, the first 100 shoulders (98 patients) were followed-up after an average time of 35 months (18 to 62 months). The recurrance rate was 9%. Excluding the first 30 shoulders (30 patients) from the development phase of the technique, the recurrance rate is only 5.7%. The rate of return to overhead sports activities was 62% and to collision sports activities 70%.