A Hill-Sachs lesion (HSL) is a compression fracture on the humeral head created when the soft humeral head impacts the edge of the glenoid during shoulder dislocation. HSL incidence is reported in 47% of acute anterior glenohumeral dislocations and in 40-80% of patients with chronic instability. A Bankart lesion, the avulsion of the anterior/inferior labrum and inferior glenohumeral ligament from the glenoid rim, is often accompanied by a HSL. Soft tissue repairs are often unsuccessful when a significant bony defect is left untreated; it is our long-term goal to determine which bony defects should be treated to prevent failure of soft tissue repair. Surgeons have proposed the presence of "large" HSLs or the position and orientation of the HSL as causes for recurrent dislocation following Bankart repair. Unfortunately, in the orthopedic literature there is no system for classifying HSLs, or even for quantifying their size, position, and/or orientation which precludes the objective comparison of the work of various authors. The development of such a system is the necessary precursor to the production of any meaningful conclusions about the significance of the HSL. An inexpensive medical image segmentation process using active contours was implemented to build 3D reconstructions of the humeral head. Each of the active contour parameters was optimized for the clinical data set. Literature studies were conducted to come to a consensus on critical lesion traits and methods for computationally quantifying the lesion's traits. The long-term goal of this study is to compare clinical outcomes to the quantitative measures determined using this method.Digitized from a paper copy provided by the Physiological Sciences Graduate Interdisciplinary Program
