ANATOMY

The peritrochanteric space is a well-defined compartment between the greater trochanter and iliotibial band and is occupied by the trochanteric bursa. Its borders are defined by (1) proximal sartorius and tensor fascia lata muscles anteriorly, (2) vastus lateralis inferomedially, (3) anterior tendon of the gluteus maximus inserting into the iliotibial band distally, and (4) gluteus medius and minimus tendons superomedially.

The gluteus medius tendon has two separate entheses on the greater trochanter. The posterior fibers attach to the posterosuperior facet (PSF), whereas the central and anterior fibers insert on the lateral facet (LF) of the trochanter. The facets are oriented at different planes relative to one another (Figs. 10-1 and 10-2).⁷ The tendinous portion inserting into the PSF is robust, with a circular insertion site of approximate radius of 8.5 mm. The surface area of this insertion is approximately 200 mm². The lateral facet insertion is more rectangular in shape, with a surface area approximating 440 mm².

FIGURE 10-1 Cadaveric dissection of greater trocanther demonstrating gluteus medius insertion footprints at the superoposterior (SP) and lateral facets, and their relationship to the vastus tubercle and gluteus minimus insertion. There is a bald spot that lies between the insertion of the gluteus medius on the lateral facet and the insertion of the gluteus minimus on the anterior facet.

(From Robertson WJ, Gardner MJ, Barker JU, et al. Anatomy and dimensions of the gluteus medius tendon insertion. Arthroscopy. 2008;24:130-136.)

FIGURE 10-2 The greater trochanter has been divided into four anatomical facets by Dwek and colleagues—superoposterior, lateral, anterior, and posterior. The medius inserts on the superoposterior and lateral facets, whereas the minimus attaches to the anterior facet. The posterior facet is covered by the trochanteric bursa.

(From Dwek J, Pfirrman C, Stanley A, et al. MR imaging of the hip abductors: normal anatomy and commonly encountered pathology at the greater trochanter. Magn Reson Imaging Clin North Am. 2005;13:691-704.)

The trochanteric insertion of the gluteus minimus is separated from the proximal portion of the LF footprint by the trochanteric bald spot. Near the midsubstance of the LF footprint, the bald spot ends and the long head of the minimus begins. At this location, the medius footprint abuts and covers a portion of the gluteus minimus.⁷ The trochanteric bald spot is circular in shape, with a radius of approximately 11 mm. Although it combines with the gluteus medius to comprise the entire lateral facet of the greater trochanter (see Fig. 10-1 and 2), it is critical not to overestimate the size of tendon detachment with an abductor tear by mistakenly incorporating the normal bald spot into the anatomic footprint of the medius tendon.⁶

The anatomically distinct insertions of the medius are thought to correlate with anatomically distinct portions that function in a phasic manner during the gait cycle. The posterior portion that inserts into the PSF is thought to stabilize the femoral head in the acetabulum during heel strike. The central portion, inserting into the PSF and LF junction, runs more vertically and is thought to be critical in initiating hip abduction. The anterior portion aids in abduction but also functions as an external rotator of the pelvis during swing-through on the contralateral limb.⁷

CLASSIFICATION

Dwek and associates⁸ and others^9–14 have described a standardized MRI approach to abductor tear classification. They have divided the greater trochanter into four facets—posterosuperior, lateral, anterior, and posterior (Fig. 10-3; see Fig. 10-2). The minimus attaches to the anterior facet (see Fig. 10-3A and B). Figure 10-3A shows the normal attachment of the minimus and Figure 10-3B shows the corresponding image demonstrating a gluteus minimus tear. The medius inserts on the lateral and posterosuperior facets (see Figs. 10-3C-F). Figures 10-3C and E show the normal insertional anatomy of the medius on the LF and PSF whereas Figures 10-3D and F show corresponding images demonstrating medius tendon tears at the respective facets. The posterior facet is covered by the trochanteric bursa (see Fig. 10-3G).

FIGURE 10-3 A, Axial MRI scan demonstrating the anterior facet (straight arrows) and inserting minimus tendon (curved arrow). B, Similar axial view demonstrating abnormal signal characteristics in the inserting tendon consistent with a high-grade partial tear. C, Coronal MRI scan demonstrating the lateral facet (arrowheads) and inserting medius tendon (arrow). D, The anterior fibers of the gluteus medius insertion onto the lateral facet are partially torn in this coronal image. E, Coronal MRI scan demonstrating the posterosuperior facet and the more robust tubular insertion of the medius tendon (curved white arrow). F, In this coronal image, there is evidence of partial tearing of the most lateral fibers of the posterosuperior medius insertion. G, Axial MRI scan demonstrating the posterior facet (curved white arrow). This is the only facet without a distinct tendon insertion and is the location of the trochanteric bursae.

(From Dwek J, Pfirrman C, Stanley A, et al. MR imaging of the hip abductors: normal anatomy and commonly encountered pathology at the greater trochanter. Magn Reson Imaging Clin North Am. 2005;13:691-704.)

SURGICAL TECHNIQUE

Entry into the peritrochanteric space or lateral compartment typically follows routine evaluation and treatment of pathology in the central and peripheral compartments. Central compartment arthroscopy is used for all patients who have peritrochanteric space endoscopy to document and treat any associated intra-articular pathology that may coexist with the lateral-sided pathology.

As with any arthroscopic procedure, portal placement is critical. The technique begins with accurate identification of the trochanter and anterior superior iliac spine. The anterior or midanterior portals can afford access into the peritrochanteric space. The anterior portal is placed 1 cm lateral to the anterosuperior iliac spine (ASIS) in the interval between the tensor fascia lata (TFL) and sartorius (Fig. 10-4). We prefer, however, to use a midanterior portal rather than a direct anterior portal. This is typically located 2 to 3 cm distal and 2 to 3 cm lateral to a standard anterior portal, and can be located by creating an equilateral triangle between the anterior and lateral portals.⁶ It lies directly anterior to the lateral prominence of the greater trochanter and provides the safest access to the joint by avoiding any potential injury to the more proximal gluteus medius musculature and the more distal vastus lateralis musculature. It also offers an improved angle of approach to the peritrochanteric space and minimizes risk of injury to the lateral femoral cutaneous nerve compared with a direct anterior portal. Care should be taken to avoid placing the midanterior portal too proximally or distally. A proximally misplaced portal will injure the gluteus medius belly, whereas a distally misplaced portal will injure the vastus lateralis. The use of fluoroscopic imaging can confirm placement of the portal directly over the lateral prominence of the greater trochanter and prevent inadvertent proximal or distal muscular injury.

FIGURE 10-4 Portals used for peritrochanteric arthroscopy and medius tear arthroscopic repair. Note the equilateral triangular relationship between the direct anterior, midanterior, and anterolateral portals. The distal (accessory) portal (distal anterolateral accessory) is in line with the anterolateral portal and is placed midway between the tip of the greater trochanter and the vastus tubercle, approximately 3 to 4 cm distally.

(From Voos JE, Rudzki JR, Shindle MK, et al. Arthroscopic anatomy and surgical techniques for peritrochanteric space disorders in the hip. Arthroscopy. 2007;23:1246.)

The cannula is directed into the peritrochanteric space in an anterior to posterior direction, with the leg in full extension, held in 0 degrees of adduction, 10 degrees of flexion, and 15 degrees of internal rotation (see Fig. 10–4).⁶ Traction is released prior to entry into the lateral space to relax tension on the iliotibial band. Slight abduction may also be necessary to increase the space between the iliotibial band and greater trochanter. A gentle axial load may be applied if it is difficult to distinguish the muscular fibers of the gluteus medius from the overlying bursal tissue. The cannula is swept back and forth between the iliotibial band and trochanteric bursa, using a technique similar to that used for access into the subacromial space of the shoulder. The iliotibial band is analogous to the coracoacromial ligament of the shoulder.

When the appropriate plane is identified, a clear space between the iliotibial band and greater trochanter can be easily identified (Fig. 10-5A). Typically, bursal tissue is present in the space and can be easily cleared with a motorized shaver to define the lateral (iliotibial band) and medial (greater trochanter and vastus lateralis) borders of the space more clearly (see Fig. 10-5B). With the camera focus directed distally, a distal anterolateral accessory (DALA) portal in the peritrochanteric space is established with spinal needle guidance approximately 4 to 5 cm distally and in line with the anterolateral portal. This portal allows for further distal access for diagnostic and operative intervention and provides outflow (see Fig. 10-4).⁶ A standard anterolateral portal can also be useful as a third working or viewing portal placed just proximally to the anterolateral tip of the greater trochanter. This portal can improve distal visualization and facilitate suture management with abductor repair.

FIGURE 10-5 A, A blunt trochar is swept back and forth to develop the space between the iliotibial band and trochanteric bursa, using a technique similar to that for access to the subacromial space of the shoulder. B, Once the space is developed and cleared of bursal tissue, the greater trochanter (being touched by the spinal needle) and iliotibial bands (right) can be clearly identified. The greater trochanter is analogous to the greater tuberosity in the shoulder and the iliotibial band is analogous to the coracoacromial ligament.

Diagnostic arthroscopy is initiated with the 70-degree arthroscope in the midanterior portal. The first structure visualized is the gluteus maximus inserting on the femur just below the vastus lateralis. This is a reproducible landmark and no exploration should be performed posterior to the tendon, because the sciatic nerve lies within close proximity (2 to 4 cm) to this location. Inspection then proceeds in a counterclockwise direction, starting distally and posterior at the gluteus maximus insertion and then proceeding proximally and anterior toward the vastus lateralis and gluteus minimus (Fig. 10-6).⁶

FIGURE 10-6 The initial view identifies the so-called sickle band, or insertion of the gluteus maximus running posterior to the vastus lateralis toward the iliotibial band and posterior femur. A, Viewed from the anterolateral portal looking distal, the maximus tendon insertion can be cleared of tissue and serves as a distal landmark. It is typically unnecessary to extend any surgical dissection distal to this tendon insertion. B, When viewed from the distal anterolateral accessory portal, the tendon insertion can be closely inspected. The sciatic nerve lies approximately 3 to 4 cm posterior to the maximus insertion. Instruments should not be placed posterior to the maximus insertion without direct visualization to make sure that the nerve is protected.

As the arthroscope is moved proximally, the longitudinal fibers of the vastus lateralis are identified and traced up to the vastus tubercle, looking immediately anterior to the lateral facet (Fig. 10-7).⁶ The gluteus medius tendon and muscle are best visualized at the lateral facet with the arthroscope in the proximal anterolateral portal, with the light source rotated to visualize anteriorly and superiorly (Fig. 10-8A). Visualization of the gluteus minimus can be difficult because it is usually covered by muscle tissue of the gluteus medius. By gently sweeping away medius muscle, the tendinous insertion of the minimus onto the anterior facet can be visualized (see Fig. 10-8B). Fibrous bands in this area will require excision. Hemostasis can be obtained with radiofrequency ablation or standard cautery. The fibers of the medius lie posterior to the minimus and should be carefully probed to inspect for a tear (see Fig. 10-8C). Finally, the arthroscope should be directed toward the iliotibial band. The posterior third of the iliotibial band may demonstrate abrasive changes if a symptomatic coxa saltans externus is present. An arthroscopic release can be performed if necessary (Fig. 10-9).¹⁵ The working instruments can be placed in the midanterior and distal anterolateral accessory portals if an abductor repair or iliotibial band release is necessary.

FIGURE 10-7 As the arthroscope is moved proximally, the longitudinal fibers of the vastus lateralis are identified (A) and traced up to the vastus tubercle (B), looking immediately anterior to the lateral facet.

FIGURE 10-8 A, As the camera continues proximally, the gluteus medius insertion onto the lateral facet can be identified. The muscular fibers of the medius can be seen proximal to the tendon. B, To visualize the minimus tendon insertion onto the anterior facet, the gluteus medius muscle has to be elevated, because the tendon insertion is covered by the medius. C, When evaluating the tendon insertion, the entire lateral and anterior facets should be carefully probed. A partial tear typically occurs as an undersurface injury and may be difficult to visualize directly. Correlation with the MRI scan is important during this inspection process.

FIGURE 10-9 A, Arthroscopic view of the iliotibial band. B, Arthroscopic release of iliotibial band can be performed if necessary to decompress space or in the setting of symptomatic coxa saltans externus.

The technique for repairing a full-thickness tear of the abductor tendons is similar to that described for the rotator cuff. A thorough débridement of the trochanteric bursa is performed first to decompress the compartment and improve visualization (Fig. 10-10). The edges of the tear should be débrided, and clear margins around the tear should be demarcated (see Figs. 10-10C and D). Tears can be acute or chronic, and an assessment of reparability should be performed in an analogous fashion to that for rotator cuff tears by assessing the mobility of the torn edge and quality of the tissue (see Figs. 10-10E and F).

FIGURE 10-10 A, Thickened bursa is excised with the assistance of a motorized shaver to visualize and inspect the medius insertion fully. B, The gluteus medius muscle and tendon should be cleared of bursae. C, D, A full-thickness tear with retraction of the medius tendon is appreciated. E, F, The tear edges need to be demarcated clearly and the mobility of the tendon edge is tested.

If the tear is repairable, the edges should be clearly identified and débrided to healthy viable tissue (Fig. 10-11A). Similarly, the anatomic footprint on the lateral facet should be cleared of soft tissue debris and decorticated to bleeding cancellous bone with a burr (see Figs. 10-11B and C). Suture anchors are then placed into the footprint using standard arthroscopic technique, typically through a small stab incision. A spinal needle or curved snap can be used to determine the ideal location and trajectory for anchor insertion, and confirmed with fluoroscopy (Fig. 10-12A). Placement of the anchor should be done under direct arthroscopic visualization (see Fig. 10-12B) and checked using fluoroscopy (see Fig. 10-12 C) to confirm an appropriate angle and location of insertion. Typically, two anchors will be sufficient to repair the anatomic footprint of a single tendon tear involving medius tears off the lateral facet. Adequate spacing of the anchors should allow for good bone stock between anchors (Fig. 10-13A and B). Metallic anchors are frequently used because the bone quality of the trochanter is often good, and their position can be confirmed with fluoroscopy.

FIGURE 10-11 A, B, The tear footprint is visualized and prepared for arthroscopic repair by débridement of residual tissue using a motorized shaver and electrocautery. C, The bed is then débrided to bleeding cancellous bone in preparation for anchor insertion.

FIGURE 10-12 A, The ideal trajectory for anchor insertion is determined using percutaneous insertion of a spinal needle. B, The anchor is then placed through a small stab incision with this trajectory without difficulty. C, Anchor position along the facet can be confirmed with intraoperative fluoroscopy.

FIGURE 10-13 A, Two anchors have been placed in the lateral facet, each loaded with two sutures. B, Suture management is critical once the anchors are placed. All suture management and tying should be performed through cannulas to avoid tissue incarceration within the suture. C-G, After the free edge of the tear is mobilized, a suture-passing device is used to grasp the retracted tendon edge. Simple or mattress sutures can be placed, depending on the tear configuration.

After anchors are placed, the sutures are passed sequentially through the free tendon edge using a suture-passing device (see Figs. 13C-F). Typically, the free edges of the tendon can be captured with a needle-penetrating device entering from the distal anterolateral accessory portal, and the suture can be placed in the midanterior portal. The second limb of the suture can be passed through the more distal fibers bordering on the edge of the vastus ridge using a standard suture-penetrating device. Careful suture management needs to be exercised to avoid suture entanglement. All suture passage and management should be performed through cannulas to avoid entrapment of overlying soft tissue.

Once the sutures have been passed and separated, sequential tying is performed using standard arthroscopic knot-tying technique (Fig. 10-14). Careful and complete evaluation of the tendon repair should be performed to confirm anatomic restoration of the tendon footprint and security of the repair.

FIGURE 10-14 A-F, After sutures have been passed, arthroscopic knots are tied to repair the tendon to its footprint anatomically. Platelet-rich plasma can be delivered to the tendon-bone interface prior to knot tying for biologic augmentation of healing. The repair is probed to confirm excellent reduction and security.

Undersurface partial-thickness tears in the anterior medius tendon should be carefully assessed. If they are high-grade lesions, they may be converted into full-thickness tears with a full-radius shaver and repaired using the technique described earlier. Transtendon repairs may be performed in the setting of high-grade partial tears to avoid completion of the tear. Anchor placement and suture passage may be more difficult because visualization is impaired by the intact tendon.

OUTCOMES

Voos and colleagues²⁰ have recently reviewed the short-term clinical outcomes of endoscopic gluteus medius tendon tear repairs performed by the senior author (BTK). Of 482 consecutive hip arthroscopies, 10 patients with medius tendon tears had endoscopic repair, with an average follow-up of 25 months. The patients’ mean age was 50 years and all experienced persistent lateral hip discomfort and abductor weakness that was refractory to nonoperative measures. At final follow-up, all patients reported complete resolution of pain and had 5 of 5 abductor motor strength points on physical examination. Modified Harris hip scores at 1 year averaged 94 points and hip outcomes scores averaged 93 points.²⁰

POSTOPERATIVE REHABILITATION

The general goals of early postoperative rehabilitation are a normalized gait pattern with crutches and the abduction orthosis. The hip is placed in an abduction brace postoperatively to protect the hip from active abduction and passive adduction past neutral. No active abduction and internal rotation or passive adduction and external rotation are permitted for at least 6 weeks to protect the structural integrity of the repair. Passive hip flexion to 90 degrees and passive abduction, however, is permitted as tolerated. Weight bearing is restricted to 20 pounds of foot-flat on the involved extremity for the first 6 weeks postoperatively. Continuous passive motion is initiated immediately for 4 hours, as well as stationary biking for 20 minutes daily. This is continued for the first 4 to 6 weeks postoperatively to avoid adhesions. Scar massage of the portals is initiated after initial healing at 10 to 14 days postoperatively.

Isometric strengthening of hip extensors, adductors, and external rotators and quadriceps neuromuscular stimulation is initiated at 2 weeks postoperatively. Active hip strengthening is initiated at 4 to 6 weeks postoperatively, starting with isometric, submaximal hip flexion and quadriceps strengthening. Gradual progression to weight bearing as tolerated with crutches and progressive passive hip internal rotation, external rotation, and flexion to more than 90 degrees is allowed at 6 to 8 weeks postoperatively.

By 10 weeks, lower extremity strengthening, core strengthening, and proprioceptive training are progressed as tolerated. By 3 to 6 months, patients should be pain-free, with quadriceps and hamstring peak torque strength within 15% of the contralateral extremity on isokinetic testing. Furthermore, they should demonstrate a normal step-down test and score at least 85% or higher on the single-leg crossover triple hop for distance.