Purpose. Our understanding of the spectrum of pathological lesions of the shoulder anterior capsular-labral complex in anterior instability continues to evolve. In a previous study using magnetic resonance arthrography we have showed three variants of the essential lesion of the anterior capsular-labral complex. This is the first large arthroscopic study to finely evaluate the nature and relative proportions of these three lesions in anterior instability. Methods. We studied 122 patients, 101 male and 21 female patients with an average age of 28 (17 to 47 years old), undergoing primary arthroscopic stabilization for anterior instability between 2004 and 2008. The pathoanatomy of the anterior capsule-labral complex was documented. Based on our previous MRI arthrography experience we were able to categorize the lesions seen arthroscopically in three subgroups: the Bankart lesion, the Perthes lesion and the ALPSA (anterior periosteal sleeve avulsion). Results. Arthroscopic findings confirmed the presence of the triad of essential lesion. The relative proportions of the subcategories of the essential lesion were as follows: 71 (58%) Bankart lesions, 18 (15%) Perthes lesions and 33 (27%) ALPSA lesions. Each lesion has unique characteristics, which affect treatment and prognosis. We describe the three types of labral injury and the surgical implications. Conclusion. The literature on the essential anterior capsular-labral lesion has historically focused on the Bankart lesion. There are in fact three variants of the essential lesion: the triad of Bankart, ALPSA and Perthes. This study evaluates these lesions and quantifies their relative proportions in a large series. We believe that awareness of this sub classification of the essential lesion is important as it affects the management of this condition

Background. The functional outcome and risk of recurrence following arthroscopic stabilisation for recurrent anterior shoulder instability is poorly defined in large prospective outcome studies. This is the first study to prospectively evaluate these outcomes in patients who have been treated using this technique. Methods. We performed a prospective study of a consecutive series of 302 patients (265 men and 37 women, mean age 26.4 years) who underwent 311 (9 bilateral) arthroscopic Bankart repairs for recurrent anterior instability. Patients were evaluated preoperatively and postoperatively at 6 months, and annually thereafter. The chief outcome measures were risk of recurrence and the two-year functional outcomes (assessed using the WOSI and DASH scores). Results. On survival analysis, the overall re-dislocation rate after surgery was 13.5% (42/311 shoulders). The median time to recurrence was 12 months (range 3 to 110 months) and 55% of these developed recurrent instability within 1 year of their surgery. The median follow-up in those patients who did not re-dislocate was 70 months. There was a significant improvement in the WOSI and DASH scores at 2 years postoperatively of 21.4 and 9.9 points respectively (both p<0.001). The risk of redislocation was significantly increased by the presence of glenoid bone loss associated with or without a Hill-Sachs lesion, and the type and engagement of a Hill-Sachs lesion on arthroscopic examination (all p<0.001). However, the risk in these sub-groups was lower than that reported in previous studies. A multivariate model was produced from these parameters to estimate the risk of recurrence at the time of primary surgery. Conclusions. The majority of patients have successful functional outcomes and relatively low risk of recurrence following arthroscopic stabilisation. The identification of preoperative factors which increase the risk of instability has enabled us to better counsel patients of their risk of failure following arthroscopic repair