Subspine Impingement and Surgical Technique

Abstract

Femoroacetabular impingement is one of the causes of hip pain leading to acetabular labral tears and articular cartilage damage via mechanical overload that may lead to the development of early osteoarthritis. However, other causes of impingement have been described that may be associated with painful nonarthritic hip. Subspine impingement is caused by abnormal contact between the AIIS (anterior inferior iliac spine) and proximal femur with straight hip flexion. A classification system of the AIIS morphology has been proposed which may provide valuable information for the preoperative surgical plan. Radiographs, magnetic resonance imaging, ultrasound, or computed tomography may help to better elucidate the problem and differentiate between intra- and extra-articular pathology. Arthroscopic subspine decompression has provided good to excellent patient-reported outcomes. Complex AIIS morphologies combined with significant intraarticular pathology can make the arthroscopic procedure challenging. Since long-term outcomes of arthroscopic subspine decompression are still forthcoming, safety should be the first priority. This can be accomplished by following specific principles such as detailed preoperative planning by utilizing advanced imaging modalities, avoidance of long traction times, and fluoroscopic imaging intraoperatively to assure adequate and accurate AIIS and cam resection.