Evaluation and Management of Hip Pain
The Emerging Role of Hip Arthroscopy
Christopher M. Larson, MD; Jennifer Swaringen, MD; Grant Morrison, MD
THE PHYSICIAN AND SPORTSMEDICINE - VOL 33 - NO. 10 - OCTOBER 2021
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In Brief: Hip arthroscopy is increasingly used as a tool for evaluating and managing painful hip in active patients. The complex anatomy of the lower back, abdomen, pelvis, and upper thigh can make the diagnosis challenging. A thorough history and physical examination in addition to specific imaging modalities can verify the presence or absence of various intra-and extra-articular disorders of the hip. Although hip pain in athletes is often managed conservatively, specific disorders and injuries are appropriately and successfully treated with hip arthroscopy.
The many potential sources of referred pain that affect the hip can make diagnosis and management of hip pain very complex in active patients. Hip arthroscopy allows treatment of pathology that may have previously gone undiagnosed or may have required treatment with more invasive traditional procedures. Many athletes have returned to preinjury activity levels after treatment with hip arthroscopy.
The hip joint is made up of the femoral head and acetabulum (figure 1). This ball-and-socket joint is inherently stable in most situations. The femoral head and peripheral acetabulum are covered with hyaline cartilage. The labrum consists of fibrocartilage, much like the menisci in the knee, and is attached to the acetabular articular cartilage via a thin transition zone of calcified cartilage on the articular side.1 The non-articular side of the labrum is directly attached to bone.1 The anterolateral portion of the labrum has the most pain fibers, and the peripheral one-third receives a rich blood supply.1,2 The central two-thirds of the labrum is relatively avascular, which accounts for its low healing potential.1,2 The labrum also appears to increase hip stability by increasing the acetabular depth and helping to create negative intra-articular pressure.1,3 The ligamentum teres, which runs from the center of the acetabulum to the femoral head, may provide an additional stabilizing effect.4 The hip joint is surrounded by the hip capsule (ie, the iliofemoral, pubofemoral, and ischiofemoral ligaments) that may also play a stabilizing role.
Evaluation of the Active Patient
Hip pain can arise from a number of sources (table 1). History may include a torsional event, fall directly onto the lateral hip, or hyperextension, but often no specific injury is recalled. A patient whose activities involve repetitive hyperextension and external rotation, such as soccer, skating, hockey, tennis, or golf, may be at risk for developing intra-articular hip disorders.5 Endurance athletes, primarily runners, may have labral and chondral pathology.6
Pain is typically located in the groin and anterior-medial thigh, follows the L3 dermatomal pattern, and may be associated with mechanical symptoms. Byrd7 described the classic "C" sign, whereby patients place their index finger over the anterior aspect of the hip and place the thumb over the posterior trochanteric region to indicate the location of their pain. Patients often report pain with prolonged hip flexion or torsional activities, when arising from a seated position, while putting on socks and shoes, or when descending and ascending stairs and inclines.
A thorough physical examination is paramount when evaluating active patients who have hip pain. First, the patient's gait should be evaluated. Patients may ambulate with a Trendelenburg gait, indicating hip abductor weakness or extra-articular pathology. A gait with a shortened stance phase is often more consistent with intra-articular pathology. Active and passive range of motion should be evaluated and compared with the contralateral side.
Specific tests are used to diagnose hip joint pathology. The impingement test is performed with hip flexion, adduction, and internal rotation and recreates pain for various intra-articular disorders (figure 2).7,8 The supine log rolling test is the most specific test indicating intra-articular pathology, but it is not very sensitive.7 The resisted supine straight-leg raise and the single-leg deep knee bend or lunge test can also elicit pain in patients with intra-articular pathology.9 Moving the hip from flexion, external rotation, and abduction to a position of extension, internal rotation, and adduction can recreate pain secondary to anterior hip joint pathology or reproduce snapping caused by iliopsoas snapping hip and tendinitis.
Palpation of the hip and strength testing should be performed as well. The lower back, radicular symptoms, peripelvic musculature, and intra-abdominal structures should also be evaluated. Several articles have focused specifically on the assessment and differential diagnosis of patients presenting with a painful hip.7,9,10
For patients who have hip pain, plain radiographs can reveal osteoarthritis, avascular necrosis, calcified loose bodies, femoroacetabular impingement, active and residual slipped capital femoral epiphysis and Legg-Calvé-Perthes disease, stress fractures of the pelvis and proximal femur, apophyseal avulsions, and, in some cases, tumors. The most sensitive study used to evaluate hip pain is magnetic resonance imaging (MRI) with intra-articular gadolinium (figure 3).11,12 False-negatives and false-positives are still problematic and may depend on interpreter experience.11 MRI is insensitive for evaluating focal chondral lesions and ligamentum teres pathology. For arthrography, we recommend including an anesthetic agent along with the contrast. The response to an intra-articular anesthetic injection may be the single most important diagnostic factor when evaluating patients who have a possible intra-articular source of hip pain.11 Bone scans can be helpful when symptoms are vague and poorly localized and can reveal increased uptake with disorders such as stress fractures, bone tumors, osteitis pubis, athletic pubalgia, infections, osteonecrosis, and femoroacetabular impingement.
Indications for Hip Arthroscopy
For active patients who have hip pain that has not been relieved by a course of physical therapy, analgesics, relative rest, and occasional selective injections, hip arthroscopy may be indicated. Hip arthroscopy is used for a growing list of conditions, including labral tears, chondral lesions, loose bodies, ligamentum teres lesions, femoroacetabular impingement, instability, iliopsoas snapping hip, pigmented villonodular synovitis, septic hip, and select cases of osteoarthritis and avascular necrosis with mechanical symptoms.
Labral tears are the most common hip joint pathology in athletes. Some athletes remember a specific mechanism of injury; however, many present with the insidious onset of hip pain without obvious antecedent trauma. Typically, pain is recreated with torsional movements and is localized to the groin and medial thigh. On physical examination, the impingement test often recreates the pain in anterior and superior labral tears, whereas posterior labral tears will occasionally result in pain with flexion and external rotation. MRI arthrography will often clinch the diagnosis, and an intra-articular anesthetic injection will temporarily relieve the patient's symptoms.
Very little evidence supports nonoperative treatment of labral tears. One study13 had an 86% success rate (six of seven patients) treating acute labral tears with protected weight bearing. Another study,14 however, found only 13% (7 of 55) were successfully treated with protected weight bearing. We have had several patients with acute labral tears who have been successfully treated with protected weight bearing for up to 6 weeks. Most, however, had continued disability and eventually underwent arthroscopic labral debridement or repair (figure 4). Most patients who come to our clinic have had pain for months to years, and they have been previously treated with multiple courses of physical therapy.
It is appropriate to prescribe core trunk strengthening and, occasionally, postural restoration therapy if minimal or inadequate therapy has been attempted prior to evaluation. For patients with pain continuing beyond 4 to 6 weeks, arthroscopic debridement and, less frequently, repair of peripheral tears can result in excellent symptom relief in 70% to 90% when large chondral lesions are absent.4,15-20
Commonly found in conjunction with labral pathology, focal full-thickness chondral lesions can result from torsional activity or direct lateral impact on the greater trochanter. Patients who have chondral lesions will present with pain similar to that of labral pathology. Forced internal and external rotation of the hip will often recreate the pain.
Because MRI is often insensitive in identifying chondral pathology, noting the patient's response to an intra-articular anesthetic injection is very useful. Full-thickness focal defects found at the time of hip arthroscopy can be treated with debridement, abrasion arthroplasty, or microfracture (figure 5). Little in the literature pertains to the results of these procedures in active patients. One study17 found that the size of the lesion was prognostic, because more than 70% of patients with lesions smaller than 1 cm had good to excellent results, compared with 40% for those with lesions larger than 1 cm. Currently, no data exist about the utility of chondrocyte transplantation or ostechondral grafting for hip joint chondral defects.
Ligamentum Teres Lesions
Awareness of ligamentum teres lesions in athletes is increasing.11,15,21 The typically reported mechanisms of injury are motor vehicle accidents, falls from a height, and football, skiing, and hockey injuries.21 Patients often report deep groin pain and, occasionally, mechanical symptoms. On physical examination, forced rotation will often reproduce the patient's symptoms. MRI is not very accurate in diagnosing these lesions, and arthroscopy may reveal a partial rupture, complete rupture, or bony avulsion presenting as a loose body (figure 6). Many patients who have ligamentum teres lesions show remarkable improvement when treated with arthroscopic debridement.21
This condition is receiving increasing attention. The typical young-to-middle-aged patient with femoroacetabular impingement reports groin pain. Some patients have a gradual onset of symptoms, and others may have a history of injury or repetitive injuries. The prominence located on the anterolateral head-neck junction impinges against the acetabulum and labrum with hip flexion and internal rotation. Over time this can lead to chondral and labral pathology. Often, no joint-space narrowing is detected, and, frequently, radiographs are read as normal. The condition can remain undiagnosed for years. Physical therapy can be attempted for these patients, but it will often increase symptoms caused by the structural abnormalities and exacerbate repetitive impingement with activities.
The impingement test is positive in patients who have a history of injury or repetitive injuries, and plain radiographs have a characteristic appearance.8,22,23 On a true anteroposterior and cross-table lateral radiograph, morphologic abnormalities can be seen around the femoral head-neck junction, acetabulum, or both (figures 7 and 8). Films may reveal a degree of acetabular retroversion, and the proximal femur may have a short head-neck offset or "pistol grip" deformity.
Traditionally, treatment involves open labral and chondral debridement and proximal femoral and/or acetabular reshaping. Recently, success has been reported with arthroscopic procedures.16,22-24 Patients often report good relief of their groin pain, and the impingement test is negative if the intra-articular pathology and morphologic abnormalities are concurrently addressed.16,22-24
The shape of the hip joint is inherently stable when compared with other joints. Occasionally, patients may develop a degree of instability that can lead to intra-articular pathology or become painful. Hypermobile patients and those with connective tissue disorders may be particularly predisposed to hip joint instability. Participants in sports that require axial loading with repetitive hip rotation, especially external rotation, are prone to instability. These activities include baseball, ballet, gymnastics, football, figure skating, and golf.4,25 On examination, these patients will often have increased external rotation with associated pain, generalized ligamentous laxity, and a patulous hip capsule at the time of hip arthroscopy.
The diagnosis can be difficult to make, and the literature is sparse regarding objective diagnostic criteria or treatment results. Early reports of capsulorrhaphy or capsular tightening procedures indicate good symptom relief in carefully selected individuals for whom a well-designed physical therapy program was unsuccessful.24,25
Other Roles for Hip Arthroscopy
Removing loose bodies caused by trauma or synovial chondromatosis has resulted in excellent relief from pain and mechanical symptoms in athletes. Hip arthroscopy can also be used to help stage avascular necrosis and treat mechanical symptoms caused by unstable osteochondral fragments and loose bodies.19,26 Patients may present with snapping hip caused by the iliopsoas tendon snapping across the pelvic brim or femoral head-neck junction. Symptoms are often recreated by having the patient extend a flexed, abducted, and externally rotated hip.
The diagnosis can be made on clinical exam and verified with dynamic ultrasound or fluoroscopic bursography. When physical therapy and corticosteroid bursal injections fail to provide sustained relief, release or lengthening of the iliopsoas tendon can be considered. Traditionally, this is done through an open approach, but we have had success with arthroscopic release and lengthening of the tendon through iliopsoas bursoscopy.27
Hip arthroscopy can be considered in a select group of patients who have osteoarthritis. Those patients with mild-to-moderate osteoarthritis, and mechanical symptoms caused by labral tears, unstable chondral flaps, or loose bodies may have relief after arthroscopic management. In the absence of mechanical symptoms or in the case of severe osteoarthritis, hip arthroscopy has not been successful for most patients.17
Ultimate Goal of Arthroscopy
The diagnosis and management of athletes presenting with hip pain is often frustrating for both the patient and healthcare provider. A thorough history, physical exam, and appropriate imaging and diagnostic injections can help diagnose and minimize disability time for most patients. With the increasing awareness of the utility of hip arthroscopy, many patients can return to preinjury levels of activity through this minimally invasive approach. Further studies and longer-term follow-up should better define the role for hip arthroscopy in treating active patients who have hip pain.
Dr Larson is an orthopedic surgeon at Orthopaedic Consultants in Minneapolis and Director of Medical Education at Minnesota Sports Medicine in Eden Prairie, Minnesota. Dr Swaringen is an orthopedic sports medicine fellow at Minnesota Sports Medicine. Dr Morrison is a family practice physician at Edina Sports Health and Wellness in Edina, Minnesota, and holds a certificate of added qualifications in sports medicine.
Address correspondence to Christopher M. Larson, MD, Minnesota Sports Medicine, 775 Prairie Center Dr, Eden Prairie, MN 55344; e-mail to [email protected].
Disclosure information: Drs Larson, Swaringen, and Morrison disclose no significant relationship with any manufacturer of any commercial product mentioned in this article. No drug is mentioned in this article for an unlabeled use.