Cam-Type Impingement: Ensuring an Ideal Femoroplasty

Abstract

When conservative measures have failed, arthroscopic femoroplasty has proven highly efficacious in treating femoroacetabular impingement (FAI) and improving hip joint mechanics. It is best to approach this in a systematic manner with preoperative planning and intraoperative confirmation. Plain radiographs, MRI and/or CT are helpful in the preoperative assessment with identifying the location and shape of the cam deformity. Understanding the extent of the cam lesion prior to surgical intervention will aid in the resection process. The resection can then be confirmed by an intra-operative fluoroscopic exam and arthroscopic dynamic motion evaluation under direct visualization. Using the trough technique, the resection can be marked using the cortical-cancellous border as a depth landmark. When performing the resection, a smooth contour should be performed, with an understanding that both over and under resection can be problematic. Adequate resection should be ensured by testing range of motion, with fluoroscopic imaging, to obtain a circumferential view of the resected area. It is essential to understand how to position the lower extremity in order to obtain different fluoroscopic views of the femoral head neck junction clock-face. Once complete, a thorough irrigation of the joint should be performed to remove bony debris. An ensuing capsular closure should be performed to minimize the risk of iatrogenic hip instability.