Introduction

Hip pain in young adults is often characterized by nonspecific symptoms, normal imaging studies, and vague findings from the history and physical examination. As such, identifying the source and mechanism of the pain can be difficult. At the same time, treatment needs to be specific, because its effects will be experienced longer in this population. Emphasis will be placed on a newly established frequent cause of hip pain in the young adult called femoroacetabular impingement, which is a subtle form of early degenerative hip disease. A thorough arthroscopic correction of this pathology will be presented. The technique treats the acetabular component as well as the head component. This also includes labral suturing and cartilage transplantation, when necessary.

However, for such complex arthroscopic reconstructive surgery, longer traction times are necessary. It has been reported that traction times of more than 90 to 120 minutes on a traction table can provoke severe neurologic and perineal skin lesions in up to 15% of cases. The most frequent neurologic lesions reported are pudendal nerve lesions that result in clinical impotence as a result of the compression of the nerve on the perineal post of a traction table. Sciatic and femoral nerves are also at risk because of the overstretching that occurs during longer periods of time. Because these reconstructive procedures are time consuming, have a steep learning curve, and, above all, can provoke fearful complications, we have used invasive hip distraction (DR hip distractor, DR Medical, Solothurn, Switzerland) for these indications (Figure 12-1, A). Thus, by avoiding the need for traction against a perineal post with a traction table, we have not encountered the previously mentioned complications that occur with the use of the invasive hip distraction technique. The hip distractor allows the surgeon to perform these time-consuming surgical steps without the pressure of time to attain the same degree of perfection as occurs with open surgery. The results obtained are therefore identical to those of the open surgical technique. This is also a wonderful teaching tool, because beginners can also perform these more complex procedures without worrying about distraction time and the related complications.

Figure 12–1 A, Posterior view of right hip with the invasive hip distractor installed. Note the anterior-to-posterior precision screw mechanism (left), which allows for an increase in the anterior-to-posterior traction vector, thus opening the anterior joint space. The proximal-to-distal traction is controlled by the distal (right) precision screw mechanism. B, The proximal-to-distal controlled traction mechanism.

Basic science

Sufficient hip distraction involves traction forces of about 250 N to 500 N. After the suction seal is broken, the force needed diminishes significantly. However, on a traction table, much of the traction force is lost by uselessly distracting the knee (about 5 mm) and ankle joints (another 5 mm). After the invasive hip distractor has been installed, it produces a traction force of 500 N exclusively on the hip joint; this force is calculated in the elasticity of the dedicated Schanz screws. After this traction force is attained, the dedicated Schanz screws will be seen on the image intensifier to start bending (Figure 12-2, A through D).

Figure 12–2 A, Image intensifier view. Two distal Schanz pins in place at the level of the lesser trochanter. B, Two proximal Schanz screws 1 cm above the acetabular sourcil. C, Lower limb in neutral position with same view as that seen in part B but with traction applied. Note that 12 mm of joint space distraction is already visible in this young and muscular patient. The proximal Schanz screws have started to bend, thus signaling a sufficient 500 N of distraction force. D, Lower limb in 30 degrees of abduction. Note 18 mm of distraction (i.e., three times the diameter of the 6-mm Schanz screws). E, Same view as that seen in part D but after cam (i.e., pistol grip head) component correction with a burr.

In addition, on a traction table, the femoral head has a tendency to slide anteriorly and to reduce the anterior joint space because of the acetabular anteversion. However, most often, the lesions are in the anterior and superior regions, and most surgeons prefer to internally rotate the lower extremity to avoid this anterior joint space narrowing on a traction table. Internal rotation moves the sciatic nerve anteriorly and thus puts it at risk if the surgeon chooses a posterolateral portal approach. Invasive hip distraction avoids this by allowing for a controlled anterior-to-posterior traction vector in neutral rotation (Figure 12-3, A and B). A posterolateral portal approach is thus very safe without putting the sciatic nerve at risk.

Figure 12–3 A, Schematic view of a left hip with four Schanz screws in place showing the anterior-to-posterior traction forces that open the anterior joint space without the need for internal rotation. B, Anteroposterior schematic view of a right hip with the proximal acetabular and distal femoral Schanz screws.

Indications

Surgical technique

We have tried the lateral and supine approaches for this indication. We are largely in favor of the lateral decubitus position, and the setup is in a way that is similar to that of the classic lateral approach, with some differences. Three standard arthroscopy portals are used: the posterolateral portal, the anterolateral portal, and the anterior portal (Figure 12-4).

Figure 12–4 Proximal view of the setup of a right hip with invasive distraction and posterolateral (PL), anterolateral (AL), and anterior (A) portals.

We have abandoned the use of a traction table for hip arthroscopy as a result of a high associated neurologic complication rate. Although we followed the standard recommendations to avoid the neurologic complications of hip arthroscopy that were found in the literature (e.g., the use of a very large perineal post), of our first 20 cases, two slowly regressive pudendal nerve lesions with clinical impotence were encountered. These complications were likely the result of the fact that more than 90 minutes of traction were used to correct complex acetabular anomalies. We now have experience with more than 1000 cases of hip arthroscopy, and, sadly, our operative and traction times have not changed; this is because more and more complex cases are operated on arthroscopically and because labral suturing is necessary in about a third of cases. In the case of labral suturing, an average of four anchors is necessary, with some cases requiring eight anchors; this anchoring is of course time consuming, and it puts the nerves at risk. For this reason, since 2000, we have been using an invasive hip distraction device (see Figure 12-1, A and B), which is still in use at our institution. The device avoids the use of the perineal post, which is responsible for the pudendal nerve lesions. For more than 1000 cases, we have not documented a single nerve lesion as a result of traction with this type of hip distraction. Neurologic complication rates from procedures that involve the use of traction tables can be as high as 10% to 15%. These complications are certainly also related to experience with the technique and thus also to traction times. However, as mentioned previously in the case of complex surgery, the acetabular corrective surgery can be time consuming, particularly if labral reattachment or autologous cartilage transplantation is involved.

We prefer the lateral approach and invasive hip distraction for the following practical reasons: