Arthroscopic Treatment of Femoroacetabular Impingement
J. W. Thomas Byrd
Understanding and Planning for Treatment of Femoroacetabular Impingement (FAI)
• Distinguishing FAI morphology from FAI pathology
• The etiology of pathologic FAI often is multifactorial (“perfect storm”).
• FAI may explain why damage occurs, but how are some individuals lifelong compensators?
• Numerous factors coming together just wrong lead to joint damage.
• All factors may never be identified, but enough factors should be treated with both surgical and nonsurgical means to achieve symptomatic improvement.
• Pelvic orientation influences over- or undercoverage from the anterior acetabulum.3
▪ This can be significantly influenced by lumbar kyphosis or lordosis.
▪ Coverage can be partly altered with a pelvic stabilization program.
• It is essential to know femoral version.4
▪ This can be calculated with the addition of images through the femoral condyles with either MRI or CT (Fig. 32-1).
▪ Increased femoral version may make modest cam lesions tolerable but may also increase concerns of instability.
▪ Reduced femoral version can make small cam lesions clinically relevant or result in pincertype labral failure, even in the presence of normal acetabular morphology.
• Radiographs are two-dimensional images attempting to interpret complex three-dimensional anatomy.5,6,7
• 3-D CT scans are helpful at precisely discerning bony architecture (Fig. 32-2A-C).
▪ Lower radiation dose protocols are now equivalent to a five-radiograph hip series.
• Software systems are available for dynamic analysis discerning areas of bony collision between the acetabulum and proximal femur.8
Portal Positions (Fig. 32-3A and B)9
• The anterolateral portal is the most consistent workhorse portal for viewing.
• This portal is used by most surgeons with just slight variations.
• The anterior working portal is the most often modified.
• It often is modified laterally and distally to optimize triangulation within joint.
• Modifications for anchor placement are not necessary because anchors can be placed percutaneously.
• An anterior portal often is useful for placement of far-medial anchors, avoiding perforation of the medial pelvic cortex because of a more anterior-to-posterior direction of placement (Fig. 32-4).
▪ Avoiding perforation of the acetabulum is of paramount importance.
Figure 32-4 | 3-D CT image illustrates an anchor perforating the medial cortex at the psoas groove (arrow). |
• A percutaneous distal site equidistant between the anterior and anterolateral portals allows more divergence of anchors from the acetabular surface, providing a broader safe zone for placing anchors close to the acetabular rim (Fig. 32-5).10