The abductor complex is composed of the gluteus medius, gluteus minimus, and the tensor fascia lata muscles. As a group, they aid in support of the pelvis and stability of the hip and provide the strength for a normal gait pattern. In turn, they may be subjected to traumatic injuries and systemic processes that may lead to partial or complete rupture. This complex has often been deemed the “rotator cuff of the hip.” The overall incidence of gluteus medius tears in those undergoing primary total hip arthroplasty (THA) or for treatment of femoral neck fractures has been estimated to be ˜20%.^1,2 Associated conditions that have been thought to contribute to the pathogenesis of abductor muscle tears include anatomic variants, such as genu valgum, limb-length discrepancies, and pelvic morphology leading to a predilection for iliotibial band (ITB) tightness and abrasion of the gluteal muscles against the greater trochanter. Systemic conditions found in association with hip “rotator-cuff” injuries include gout, diabetes, anabolic steroid use, chondrocalcinosis, obesity, Paget disease, and inflammatory arthropathy.² Tears of the tendon gluteal tendons often start anteriorly and propagate posteriorly and superficially.

Presenting symptoms typically include some element of atraumatic pain in the buttock, lateral hip or groin. Patients may report some early fatigue with walking, difficulty climbing stairs, and pain with sleeping or direct palpation on the side of the affected hip. These injuries are often misdiagnosed as trochanteric bursitis, degenerative joint disease of the hip, or referred lumbar spine pathology. Standard radiographs including AP, lateral, shoot through lateral, and AP pelvis are often obtained after the physical examination to assess the local bony anatomy. Greater trochanteric fractures and surface irregularities can be found, with the latter suggestive of gluteus medius tears. MRI and ultrasonography afford a better picture of the soft tissues about the hip when searching for the appropriate diagnosis. Historic studies favor MRI as the diagnostic modality of choice (91% accurate and 95% specific) in the diagnosis of gluteal
muscle injuries.^3,4,5 Sutter et al found that patients with abductor tendon tears more often displayed hypertrophy of the tensor fascia lata (TFL) on MRI, which likely represents muscular recruitment to accommodate for the dysfunction of the damaged gluteal muscles.⁶

The majority of these injuries (partial-thickness tears) are successfully managed nonsurgically with unloading of the affected hip, medications (nonsteroidal anti-inflammatory agents or acetaminophen), topical agents, and/or physical therapy (home exercises or formal outpatient physical therapy). When symptoms are refractory to the aforementioned measures or there is a complete tear, then surgical management may be favored based on the health, activity level, and physiologic condition of the patient. Surgical management ranges from endoscopic techniques to open repair (similar to the rotator cuff, with many of the surgical principles being the same).^2,4 Anatomic repair is vital to the success of a repair and restoration of function. Recognizing the four facets of the greater trochanter (superoposterior, lateral, anterior, and posterior) is important as is distinguishing between the distinct insertion sites of the gluteus medius and minimus. The medius attaches to the superoposterior (posterior fibers) and lateral (anterior and middle fibers) facets while the minimus attaches to the lateral facet and the joint capsule with a “bald spot” between the attachment sites.⁵

Partial-thickness tears can be successfully managed with suture anchors and endoscopic management with substantial clinical benefit.⁷ Large (both anterior and posterior portions of the tendon), and full-thickness tears are best treated with open management reconstructing the anatomic tendon footprint with the reconstruction.³ Makridis reported on 67 patients treated with an open double-row technique to repair gluteal tendon injuries with 85% good clinical results and 11 failures at an average of 4.6 years follow-up.⁴ Additionally, he noted that muscular atrophy on preoperative MRI had a negative impact on functional outcomes. This has been confirmed more recently by Thaunat et al in a study on functional outcomes after endoscopic gluteus medius repair.⁸ They found that fatty degeneration of the gluteus medius and minimus had a negative impact on functional and clinical outcomes after tendon repair.

During the reconstruction of the gluteal tendons, some have recommended local decortication of the greater trochanter to aid in healing; however, recently Putnam et al have called this practice into question.⁹ In a cadaveric study, they found decreased pullout strength of suture anchors when cortical bone was removed or the bone density was poor and encouraged surgeons to consider these factors during the repair process. In the past, gluteal repairs have failed in up to 35% of cases; while modern techniques have improved upon these rates, there have been reports of using adjuncts such as acellular human dermal grafts to aid in such repairs.¹⁰ With increasing success of these repairs (reduction in prior complication rates as highs as 19% of cases⁵) and expanding indications for endoscopic reconstructions, a significant amount of research has been focused on improving the outcomes for our patients with gluteal tendon injuries.

Postoperative rehabilitation and restrictions are vital to the success of these repairs. Most suggest an abduction brace with crutches and protected weight bearing for 4 to 6 weeks after surgery. Progressive return to activity is allowed at 3 months and strengthening programs will commence moving forward.

Lateral-sided hip pain is a common condition that has been reported to be as debilitating as end-stage degenerative joint disease and is now more commonly recognized as a conglomerate of conditions (snapping hip, trochanteric bursitis, and gluteal tendinopathy) lumped together as greater trochanteric pain syndrome (GTPS).^11,12 In patients between 50 and 79 years of age, GTPS was found in 15% of women and 6.6% of men in one hip.¹³ Lateral hip anatomy is more complex than it seems with most people having three to four bursae surrounding the side of their hips. The bursae allow improved muscle mechanics over the lateral part of the proximal femur. The largest bursa is found between the gluteus maximus muscle and the gluteus medius tendon, which is located directly lateral to the greater trochanter. Coupled with the bursa the muscular sheaths and tendinous attachments of the gluteus maximus, ITB, tensor fascia lata, gluteus medius, and gluteus minimus contribute to a complex local environment that is susceptible to overuse injuries, direct trauma, and gait alterations.¹¹ Despite being a common diagnosis, trochanteric bursitis is often related to the other conditions of GTPS and not true inflammation of the local bursa.¹⁴ In making the correct diagnosis, there are many conditions that should be considered and thorough differential diagnosis can be found in Table 1. A thorough history and physical will help narrow down the differential and plain radiography, ultrasonography and MRI are adjuncts to confirm the diagnosis.

GTPS is commonly found with a valgus deformity of the lower extremity and is often relayed as a single traumatic episode by the patient or a more chronic condition (likely representing inflammation secondary
to local microtrauma). This diagnosis can often be confirmed with a local diagnostic injection and/or clinical examination. Radiographs are usually normal with GTPS; however, a trochanter protruding more lateral than the iliac crest, enthesophytes, and peritrochanteric calcifications are nonspecific findings that have are commonly seen.^11,15 Ultrasonography can be successfully used to determine the diagnosis of GTPS with a sensitivity of 79% to 100%.¹⁶ MRI is typically the benchmark to help clarify a diagnosis. Treatment for GTPS starts with nonsurgical management in the form of rest, nonsteroidal anti-inflammatory agents, physical therapy, and other modalities (ie, extracorporeal shock wave therapy—ESWT).^17,18 Rompe et al reported on 229 patients in a randomized trial of ESWT (78 patients), corticosteroid injection (75
patients), or physical therapy (76 patients) to treat GTPS. Early on corticosteroid injections appeared to be the most successful option; however, by 15 months both ESWT and physical therapy were more successful in providing sustained pain relief.¹⁸ When conservative management does not provide satisfactory relief, then surgical options can be considered after a trial of a minimum of 6 to 12 months. Surgical options include open versus endoscopic débridement of the bursa and ITB release. Overall satisfaction and success rates have been reported to be quite high with limited recurrence of the GTPS in the future.

Also known as external coxa saltans, typically occurs secondary to friction over the greater trochanter from the ITB rubbing over it. Patients (common in athletes that test the extreme ranges of hip motion) often state they can dislocate and relocate their own hip with minimal pain but shifting their leg around. Stair climbing, exercising, and squatting can lead to this snapping phenomenon as well. On physical examination as you test the hip moving it from extension (often with adduction and internal rotation) to flexion (with abduction and external rotation), the ITB may “snap” over the greater trochanter from posterior to anterior. This condition can be asymptomatic, but also can become painful and lead to overlying trochanteric bursitis and a thickened ITB.¹¹ Conservative management is the same as for GTPS and should be continued for at least 6 to 12 months before considering surgical management. Surgical management involves open versus arthroscopic release of the ITB (can be standard release or a Z-plasty) and often a bursectomy, similar to the options discussed above.

Internal snapping occurs when the iliopsoas tendon catches over the iliopectineal eminence or the anterior femoral head.¹⁹ An alternative pathological condition that has been proposed to create the snap of the hip to include movement by the iliacus muscle and the iliopsoas tendon.²⁰ Similar to external snapping of the hip, this syndrome is often asymptomatic and can occur in up to 10% of the population as a normal variant.² It may even be more prevalent in athletes whose sport requires extreme hip range of motion, such as, soccer players, weight lifters, runners, offensive lineman in football, and elite dancers.^19,21 On examination, it is reproducible when taking the hip into extension from a flexed position (like when getting in and out of a car, arising from a chair or going up and down stairs). Typically, radiographs are negative although a cam lesion may be present. AP and shoot through lateral radiographs may help assess the anatomy to include acetabular anteversion, cox vara, or developmental dysplasia.¹⁹ Psoas bursography and ultrasonography are dynamic studies that may be able to capture the snapping as it is happening.²² Approximately 50% of patients with an internal snapping hip syndrome will have associated intra-articular hip pathology that is best diagnosed with magnetic resonance arthrography (MRA). Treatment options (ie, physical therapy, deep massage, NSAIDs, injections, and myofascial release) typically involve a prolonged course of nonsurgical management similar to external snapping hip syndrome (pain relief through tendon stretching/lengthening). Modern efforts with eccentric-biased exercises and a gradual tendon loading program have shown some promise with the rehabilitation of iliopsoas tendinopathy.²³ Open and endoscopic releases have been performed and typically involve tendon release. Anatomic studies have shown that the iliopsoas tendon insertion (dual insertion of iliacus and psoas muscles) is typically on the anteromedial tip of the lesser trochanter and can be accessed at this location or anywhere along its path for an open release procedure.²⁴ There has been some debate regarding which location provides a more complete and consistent release of the tendon as at the level of the labrum the iliopsoas tendon consists of 40% tendon and 60% muscle versus the opposite percentages at the lesser trochanter.²⁵ With arthroscopic procedures, portals allow for the joint to be visualized and assessed for associated pathology. Additional portals can then be created to treat the conditions that are present. The iliopsoas tendon can be released from the lesser trochanter or via an anterior capsulotomy (transcapsular approach) to access the tendon between the anterior labrum and zona orbicularis.¹⁹ Hwang et al reported 88% good to excellent results in 25 patients treated with an arthroscopic transcapsular release of the iliopsoas tendon.²⁶ Another option is to perform a fractional lengthening of the tendon which is associated with a higher rate of recurrence (18%) and 82% good to excellent clinical results.²⁷ Heterotopic ossification is not an uncommon complication, and prophylaxis may be required in select cases. Additionally, it is important to note that in 64.2% of cases, Philippon et al found two iliopsoas tendons in a cadaveric anatomy study.²⁸ In some cases, failure to recognize the second tendon
can lead to recurrence of symptoms. When releasing the iliopsoas tendon, all patients will have some element of iliopsoas atrophy, although the clinical significance of this remains largely undetermined.