This phenomenon is always voluntary and the patient often volunteers to demonstrate it (1). Asymptomatic snapping must always be considered a normal occurrence (6). Diagnosis is evident; the snapping will occur when flexing and extending the hip (we prefer to examine this with the patient in lateral decubitus by passively flexing and extending the hip) (Fig. 31.1). In some cases the snapping phenomenon may be visible under the skin and in some other cases it may be palpated over the area of the greater trochanter by placing the full extended palm over the area (Fig. 31.2). A different form of external snapping hip is also described by some patients as the ability to “dislocate the hip.” This is often demonstrated by rotating the affected hip while tilting the pelvis in a standing position (Fig. 31.3). The voluntary “dislocators” are more frequently painless and should only be treated with stretching exercises of the ITB. Symptomatic external snapping hip syndrome is always accompanied with pain in the greater trochanteric region (Fig. 31.4). The pain is secondary to greater trochanteric bursitis, inflammation of the ITB itself, or abductor tendon pathology. A positive Ober test (6) may also be found at physical examination (Fig. 31.5). When Trendelenburg gait is also found, an associated abductor muscle tear must be suspected, this is an indication for surgical treatment. Trendelenburg may not be initially apparent, but may become positive if a fatigue Trendelenburg test is performed. This consists of asking the patient to perform a single leg stance over periods of 10 seconds with a 10-second increment in each period; if there is abductor pathology the sign becomes positive within 20 seconds. The test is carried out comparatively (Fig. 31.6) (7).

Anteroposterior pelvis x-rays should always be done to identify bony abnormalities, calcifications, or other pathology. The snapping phenomenon can be documented with dynamic ultrasonography and this examination can detect associated pathology such as tendonitis, bursitis, or muscle tears (Fig. 31.7) (7,8,9). Iliopsoas bursitis and abductor muscle tears can be diagnosed using magnetic resonance imaging (10,11).

Most of the symptomatic cases improve with stretching physical therapy, nonsteroidal anti-inflammatory therapy,


and corticosteroid infiltration of the greater trochanter bursa (1). The physical therapy protocol is established for 2 months, when the protocol is completed the patient is re-evaluated, if no improvement is obtained surgical treatment is discussed. A maximum of three corticosteroid injections are used in the area of the trochanteric bursa and rest from physical therapy is always indicated for 3 days after the injection. When conservative treatment fails, surgical release is indicated. Open ITB release or lengthening has been the traditional surgical option to treat the external snapping hip syndrome (12,13,14,15,16). Recently, we have described a technique for endoscopic ITB release for the treatment of external snapping hip syndrome (17).

Our protocol for endoscopic release of the ITB for the treatment of external snapping hip syndrome is presented (17):
We position the patient lateral similar to the setup for total hip replacement. Surgical drapes must allow for free range of motion of the lower extremity to reproduce the snapping phenomenon during surgery. No traction is necessary to access the greater trochanteric bursa and the ITB. The greater trochanter is the main landmark for portal placement and is marked on the skin using a skin marker. We utilize two portals, a proximal trochanteric and distal trochanteric (Fig. 31.8). The area of snapping should be between both portals to ensure ITB release will include the area that generates the problem. We also mark the area of snapping on the skin. We start by infiltrating the space under the ITB with 40 to 50 cc of saline. Next the inferior trochanteric portal is established using a standard arthroscopic cannula that is introduced under the skin and directed proximally to the site of the superior trochanteric portal using the blunt obturator to develop a working space above the ITB. The site of the proximal trochanteric portal is identified arthroscopically using a needle inserted at the portal landmark, the skin incision is made and a shaver is introduced to dissect subcutaneous tissue from the ITB situated between the portals. Hemostasis is performed in this step to allow clear visualization of the ITB. Then a radiofrequency hook probe is introduced from the proximal trochanteric portal and a 4- to 6-cm vertical retrograde cut is performed on the ITB starting at the level of the inferior trochanteric portal. The pump pressure should be kept low while working on the subcutaneous space to avoid complications with the skin. Once the vertical cut on the ITB is complete the pump pressure can be increased and a transverse anterior cut of 2 cm in length is performed starting at the middle of the vertical cut. The resulting superior and inferior anterior flaps are resected using a shaver developing a triangular defect on the anterior ITB that will provide access to the posterior ITB. Next a transverse posterior cut is started at the same level of the transverse anterior cut. This is the most important release and should be carried out until the snapping phenomenon is solved. Finally the superior and inferior posterior flaps are resected, which results in a diamond-shaped defect on the ITB. The greater trochanter will rotate freely within the defect with out snapping. The greater trochanteric bursa should be removed through the defect on the ITB and the abductor tendons inspected for tears (Figs. 31.9 and 31.10).

When hip arthroscopy is also necessary we start with the patient positioned lateral for hip arthroscopy, we perform arthroscopy of the central and peripheral compartments of the hip. After hip arthroscopy is complete, the foot is released from the traction device and the endoscopic ITB release performed as described.

An alternative technique has been presented by Voos et al. (18), consisting of accessing the peritrochanteric space (between the ITB and the greater trochanter) and releasing the ITB under direct arthroscopic vision from inside the thigh compartment. No results are reported in this technical note.