Hip arthroscopy for femoroacetabular impingement

Abstract

The purpose of this article is to give a general overview of femoroacetabular impingement (FAI) and how it could be treated arthroscopically, with some details about indications, the procedure itself and some of the complications associated with the surgery.FAI is a dynamic condition of the hip that can be a source of pain and disability and could potentially lead to arthritis.When symptomatic, and if conservative treatment fails, FAI can be addressed surgically.The goal of surgical treatment for FAI is to recreate the spherical contour of the femoral head, improve femoral offset, normalize coverage of the acetabulum, repair/reconstruct chondral damage and repair/reconstruct the labrum to restore normal mechanics and joint sealing.Advances in equipment and technique have contributed to an increase in the number of hip arthroscopy procedures performed worldwide and have made it one of the more common treatment options for symptomatic FAI.Hip arthroscopy is a procedure with an extremely steep and long learning curve. Cite this article: EFORT Open Rev 2018;3:121-129. DOI: 10.1302/2058-5241.3.170041.

Keywords: FAI; arthroscopy; hip.

Fig. 1

a) Normal hip clearance. b) Cam type impingement with decreased head/neck offset. The cam enters the joint pushing the labrum aside and causing a shear injury to the chondrolabral junction. c) Pincer type impingement with excessive coverage of the acetabulum. Crush injury of the labrum on the femoral neck (thin arrow) and contre-coup lesion (thick arrow).

Fig. 2

Anterior impingement test: flexion to 90°, adduction and forced internal rotation. Reproduction of the pain in this position can indicate impingement. If there is no pain, then anterior impingement is extremely unlikely.

Fig. 3

a) AP pelvis. The dotted line shows the ‘figure of 8’ which is a marker of acetabular retroversion and over-coverage so long as the radiograph was taken adequately (i.e. with no excessive pelvic tilt or rotation). It outlines the anterior and posterior acetabular walls crossing at a certain point. In cases with no over-coverage, this point is at the top of the acetabulum. The dark blue line indicates the ‘ischial spine sign’ which is another marker for retroversion. b) Modified Dunn view, showing the cam (arrow). c) Cross-table lateral, with an apparently smaller cam (arrow).

Fig. 4

CT scans showing an anterolateral cam lesion.

Fig. 5

MR arthrogram showing a labral tear with chondrolabral disruption.

Fig. 6

a) Supine position on special traction table with large padded post. The hip is initially fully abducted and slightly flexed. Both feet are in the traction boots, but traction is only applied to the operative leg. b) The hip is slightly internally rotated and the C-arm brought in to ensure adequate visualization. The C-arm is draped in this position, while ensuring that it does not obstruct the arthroscopy screen.

Fig. 7

Sequential compression devices are attached to the legs for deep vein thrombosis prophylaxis, the feet are well padded, attached to the traction boots and securely taped to them to safeguard against the feet coming out intra-operatively.

Fig. 8

Portals. AL: anterolateral portal, which is the initial portal achieved; Ant: anterior portal (working portal); DALA: distal anterolateral accessory portal; GT: greater trochanter; AIIS: anterior inferior iliac spine.

Fig. 9

Acetabuloplasty planning. Here we see the “figure of 8” again. The first step is to locate over-coverage on the ‘clock face’ of the acetabulum, in this case between 12:00 and 02:30 (thin blue arrows and blue numbers). Then the planned resection is pre-operatively templated (the red numbers). Intra-operatively the planned resection is carried out at sites of labral injury and a more conservative resection is performed at sites without injury. Care must be taken while positioning the C-arm so that the image on screen closely matches the position on the pre-operative film.

Fig. 10

a) Cartilage scuffing of the femoral head during cannula insertion. b) Labral penetration (anterolateral portal). This type of complication can be minimized with the safe entry technique. c) Kinking of the Nitinol wire which could lead to breakage within the joint.