Sports medicine disorders of the hip: Anterior-Medial

Author(s): Peter J. Moley, MD, Richard G. Chang MD, MPH

Originally published:09/16/2015

Last updated:09/16/2015

1. DISEASE/DISORDER

Definition

Anterior and medial hip disorders affecting athletes’ hip include dysfunction and/or pain affecting the anteromedial structures of the hip. These problems may be approached with “The Layer Concept,” a classification system that best determines the primary pain generator.1 The 4 layers include osseous (bone), inert (capsule/labrum), contractile (muscles/tendons), and neuromechanical (referred pain from peripheral neurovascular structures and spine).

Etiology

Etiologies of anteromedial hip disorders include direct injury to the labrum, capsule or tendon, or problems secondary to bony abnormalities such as femoracetabular impingement (FAI), which can affect the labrum, cartilage, and capsule. FAI is an anatomical abnormality at the femoral head neck junction or acetabular rim, where range of motion of the joint leads to impact at these two regions. Extra-articular impingement seen in this region includes sub-spine (anterior inferior iliac spine (AIIS) impingement. Acute and chronic musculotendoninous overuse injuries of the anterior and medial regions, especially affecting the hip flexors and adductors are other common disorders affecting this unique patient population. Stress reactions and fractures of the femoral neck and pelvis are another group of repetitive overuse disorders in the setting of altered bone turnover may be the cause of anteromedial pain in athletes.31,32 Compression neuropathies, such as ilioinguinal, genitofemoral, or obturator neuropathies and referred pain from disorders of the spine or pelvic floor, are other potential etiologies.2,3

Epidemiology including risk factors and primary prevention

Although there is no known published data on the overall incidence and prevalence of all anteromedial hip disorders in the general population, there is, however epidemiologic data depending upon the sport studied. For example, hip injuries are most commonly reported in professional ice hockey, soccer, rugby, and football players.4,5 More specifically, labral injuries have been reported in these aforementioned sports and also in golfers, rowers, dancers, karate practitioners, basketball, and baseball players.4-8 According to Epstein et al’s 2012 retrospective study of NHL players, the “cumulative incidence rate of [both hip and groin injuries was] 19.87 injuries per 100 players per year.9,10 In Feeley et al’s 2008 study of the NFL from 1997 to 2006, muscle strains (most common hip flexor), hip contusions, and intra-articular injuries (labral tears, fractures, and dislocations/subluxations) made up 59, 33, and 5% of all NFL injuries, respectively. Although representing only 5% of all injuries, intra-articular hip injuries accounted for the most time lost.4 All of these sports are prone to these type of injuries given the high mechanical stresses and loads placed on the joint, combined with motions such as cutting and extremes of hip flexion and internal rotation.2-4,11

In regards to cam impingement, there is data to suggest that cutting sports (soccer, basketball, hockey), particularly during the growth years, may lead to increased cam type deformities and impingment.5,12-14 Thus, it is important that younger pre-adolescent athletes participating in sports such as soccer or basketball be educated on avoiding extreme flexion, deep squats, and lunges to prevent the development of such femoracetabular abnormalities at the time of skeletal maturity. 5,12-14 For young athletes participating in sports such as baseball, other recommendations to prevent these abnormalities include rotating playing positions on the field.

Risk factors for the most common anteromedial hip disorders are listed below:

  1. Intra-articular hip osteoarthritis: include FAI, obesity, and advancing age15,16
  2. Stress reaction or stress fractures: include tobacco or alcohol use, osteopenia/osteoporosis, female athlete triad, female military recruits, endurance sports such as track and field, skaters 31,32
  3. Labral tears: female sex, history of Legg-Calve-Perthe’s disease; developmental hip dysplasia, instability, decreased femoral or acetabular version, decreased head-neck offset2,17
  4. FAI: labral tear, developmental hip dysplasia, age, cutting sports (basketball, soccer, football); young, active males-cam lesions, middle age females-pincer lesions17-20
  5. Athletic pubalgia or Core muscle injury: increased among football, hockey, soccer, and tennis players2,21,22
  6. Iliopsoas impingement and coxa saltans (also known as internal snapping syndrome): increased among ballet dancers and patients with rheumatoid arthritis2,7,23
  7. Sub-spine (AIIS) impingement: prior AIIS avulsion injury, acetabular overcoverage and femoral retroversion2,17

Patho-anatomy/physiology

Different mechanisms will be outlined for the most common diagnoses seen:

  1. Osteoarthritis (osteochondral layer): occurs due to abnormal joint mechanics and loading, which leads to decreased joint space narrowing, bony sclerosis, and articular cartilage loss. FAI, labral tears, hip dysplasia, and acetabular retroversion are proposed to be precursors to this non-inflammatory process, especially in younger patients before the age of 55. 15,16,24,25
  2. FAI (osteochondral layer): anatomical abnormality at the femoral head neck junction or acetabular rim with range of motion of the hip leads to impingement.

Cam type impingement is caused by an abnormal shaped femoral head or neck contacting the acetabular rim during flexion and internal rotation activities. The anterosuperior acetabular cartilage is most affected. 18,19,24-26

Pincer type impingement is caused by overcoverage of the acetabulum over the femoral head. Repeated contact leads to circumferential cartilage damage, but also posteroinferior labral degeneration (from contra-coup mechanism) and acetabular deepening 18,19,24-26

  1. Labral tears (inert layer): According to one model from McCarthy et. al., labral damage results from repeated impingement due to FAI and/or stress on the joint from developmental hip dysplasia at extreme ranges of motion. Articular cartilage damage is part of and contributes to this process if delamination of the articular cartilage occurs.27-30
  2. Rectus femoris or iliopsoas tendinopathy (contractile layer): results from improper training, repetitive loading, or trauma. 2,3,23
  3. Iliopsoas impingement (contractile layer): Psoas tendon snaps over the iliacus as the hip moves from flexion abduction, and external rotation to extension and internal rotation. Dynamic ultrasound studies have demonstrated that the psoas tendon glides over the medial part of the iliacus and the superior pubic ramus during the return of the hip into a neutral position.3,23
  4. Athletic pubalgia or Core muscle injury (contractile layer): no actual hernia exists, but shearing forces placed across the pubic symphysis from the adductors, rectus abdominae, and stresses of the inguinal wall musculature may predispose athletes to unilateral groin pain. 2,21,22
  5. L1 or L2 radiculopathies or obturator neuropathy (neuromechanical): compression of spinal nerve root and peripheral nerve secondary to commonly, a disc herniation or local trauma, respectively. 2,17,30

Disease progression including natural history, disease phases or stages, disease trajectory (clinical features and presentation over time)

Acute muscle strains tend to resolve in the acute phase with basic conservative care (relative rest, ice, compression, and elevation), whereas tendinopathies may continue to progress to chronic phases without proper eccentric strengthening programs. With hip osteoarthritis, progression is seen with further decreases in joint space narrowing, increased osteophyte formation, and bony sclerosis (severity may be graded with Tonnis Grading scale), though this may not always correlate clinically to increased pain or decreased function.15,16 Injuries resulting from untreated stress fractures tend to be more symptomatic at initial onset, but may resolve quickly and only be reproduced with specific activities. However, in the case of femoral neck stress fractures, compression sided fractures should be worked up and monitored with limited weight bearing to start, whereas tension sided stress fractures are to be immediately evaluated by an orthopedic surgeon due to an increased risk toward fracture and displacement .31,32 In respect to return to play, assessing the athlete’s level of pain and its effect on functional activities is important.32 General treatment includes a thorough work up of risk factors and treatment followed by relative rest, activity modification, and weight bearing precaution, with activity titrated using pain as a guide during an average period of 4 to 8 weeks depending on the severity of the stress fracture.32 While the stress fracture is allowed to heal, athletes should be encouraged to cross train such as swimming, cycling, or aqua-running, counseled on nutrition, and to be screened for low bone mineral density.32 Athletes who have pain from FAI and labral injuries may improve with a focused rehabilitation program that avoids motions that aggravate and reproduce symptoms.

Specific secondary or associated conditions and complications

FAI and labral tears may increase the risk for the development of early hip osteoarthritis.2,15,18,19 Associated conditions may include hip abductor dysfunction, chronic lower back pain, and poor flexibility in the quadriceps, hamstring, and tensor fascia latae and iliotibial band tendons.2,17,21

Gaps in the evidence-based knowledge

The current literature does not have any double blinded, randomized controlled studies assessing the benefits of structured rehabilitation for anteromedial hip disorders, compared to surgical options.46 There is also no data as to whether such programs also modify the natural history of degenerative joint changes found in symptomatic FAI.18 In addition, it is not known if the addition of ultrasound guided injections (whether intra-articular or percutaneous needle tenotomy with or without platelet rich plasma) may provide outcomes comparable to those found with surgical interventions.

2. ESSENTIALS OF ASSESSMENT

History

A comprehensive history should include onset and duration of symptoms, quality and character of pain or dysfunction, location, any radiating symptoms, exacerbating and alleviating factors, whether the disorder is affecting the athlete’s sport participation or performance, education (if in school), and functional activities. A past history of similar injuries, nutrition, and menses history (for females) are also relevant details.

Physical examination

The physical exam should be carried out in 5 different positions (standing, seated, sitting, supine, and prone). The standing exam assesses for “general body habitus, gait, lumbopelvic alignment, ligamentous laxity, and Trendelenberg testing for functional hip abductor weakness. The seated exam checks for any abnormalities in skin, vasculature, and lymph, while hip internal and external range of motion can be examined in this position.”33 In addition this is a good position for the neurologic examination. Here, both lower extremity sensory testing with light touch and pinprick, reflexes, and dural tension testing in the form of Seated Slump’s are assessed. The supine position is the most important, where complete passive range of motion, manual muscle strength, and provocative testing may be performed. Provocative maneuvers such as FADIR (hip flexion, adduction, internal rotation), FABER (flexion, abduction, external rotation), sub-spine impingement (straight hip flexion), Thomas test (to assess for iliopsoas tightness), and both passive and resisted straight leg tests may be used additionally to help narrow the differential diagnosis and determine what structures would need targeted therapy.17,33,34 In the sidelying position, the peritrochanteric region, lateral impingement and the stability test can be performed here. Hip abductor strength should be tested in slight extension and internal rotation of the femur to prevent iliotibial band and tensor fascial latae compensation. Lastly, the prone exam is used to assess the posterior hip structures such as the hamstrings and to assess for femoral version. At each position, the examiner would palpate at the anteromedial structures of interest (for example, pubic symphysis, ASIS, AIIS, rectus femoris, adductors), as well as lower lumbar paraspinal and posterolateral hip structures such as the greater trochanter, tensor fascia late, and posterior superior iliac spine (PSIS) to rule out referred pain sources.33

Clinical functional assessment: mobility, self care cognition/behavior/affective state

Although this varies from disorder to disorder, activities such as transitional movements, walking, stairclimbing, and deep squats are the most commonly reported to be aggravated with most anteromedial disorders. Alternative exercises such as stationary bike or a switch to more cardiac based program may be necessary while an injured athlete undergoes a specific lower extremity rehabilitation program.

Laboratory studies

No laboratory studies are routinely required unless septic arthritis is suspected. In such cases, a basic cell blood count may show leukocytosis with elevated inflammatory markers (erythrocyte sedimentation and C-reactive protein levels). Disorders involving pelvic inflammation should be ruled out in unusual cases. A full rheumatologic panel should be ordered.

Imaging

Initial workup should include plain film imaging of the hip (AP, elongated femoral neck) and the lumbar spine to rule out any overlapping spine disorders.17,35 MRI of the hip would be ordered if there is suspicion for a symptomatic labral tear or to assess for any specific tendon or muscular tear (for example, rectus femoris), or fractures.36,37 MR arthrography (MRA) is considered the best imaging modality to assess for labral tears, but this is debated.36-38Musculoskeletal ultrasound has also proved to be useful for both diagnostic and interventional purposes.39 Iliopsoas impingement, bursitis, tendinopathies, and intra-articular hip effusions may be visualized using this dynamic, real-time imaging modality.39,40 However, ultrasound alone does not adequately image the joint itself or the labrum, compared to MRI.

Supplemental assessment tools

Existing hip research tools have primarily focused on patients with either a hip fracture or arthritis such as the Harris Hip Scores. The most common measure used is the Modified Harris Hip Score. The Multicenter Arthroscopy of the Hip Outcomes Research Network (MAHORN) group developed a 33 question survey tool that was applicable to a number of common bony or labral hip pathologies.41 However, it is not applicable to muscular or referred pain from spine or knee sources. The Hip Outcome Score (HOS) has been validated for hip labral injuries.42 Other outcome measures include the Western Ontario and McMaster University Osteoarthritis Index (WOMAC), Short Form-36, Hip Disability and Osteoarthritis Outcome Score (HOOS), Non-Arthritic Hip Score (NAHS), and the Copenhagen Hip and Groin Outcome Score (HAGOS).41-45

Early prediction of outcomes

In some conditions there are factors which predict a positive outcome in anteromedial sports disorders. For example, patients without hip OA are more likely to have a positive outcome in the setting of an acetabular labral tear. In addition, similar to management of other non-surgical musculoskeletal diagnoses, the principles of close follow up, compliance with prescribed treatment, and a solid, physical therapy program will generally alleviate and improve patient’s ailments.

Younger age, female sex, hip dysplasia, instability, and both residual intra-and extra-articular impingement were risk factors for revision arthroscopic or open hip preservation surgery identified in a cross sectional study of 147 patients.61

Environmental

Environmental factors include whether the sport is played indoor or outdoor, the type of surface or terrain that is used, and any related clothing, equipment, or gear that is used. Hip motion and extremes of flexion and internal rotation can affect the condition of the hip. Athletes may be counseled on modifying these environmental factors in the management of their hip conditions. For example, reducing training during growth years, cross training, or adding orthotics to their shoes if pes planus is found on exam.

Social role and social support system

When athletes or patients are not actively engaging in their preferred sport or exercise, depressive or anxious feelings may arise. Thus, it is important to educate and counsel athletes, families, and personal trainers/coaches regarding alternative sports and exercises they may safely participate in, while they are being treated.

Professional issues

(Identify and/or consider issues relevant to this topic in the areas of ethics, quality of life, professionalism and safety.)

Education and open communication with the athlete’s family, friends, athletic trainers, and coaches is necessary to prevent recurrent injury and to maintain effective physician-team rapport. Special precaution must be considered with varsity college or professional athletes, as there may often be a financial incentive or institutional pressure to return to play sooner. In such cases, emphasis must be placed that the athlete’s health, and safety is priority and paramount.

3. REHABILITATION MANAGEMENT AND TREATMENTS

Available or current treatment guidelines

There are no known consensus statements or treatment guidelines to treat most of the disorders discussed above. There is abundance in the literature in support of surgical management of such conditions, especially in FAI and labral tears, but there are no double blind, randomized controlled trials comparing the efficacy of physical therapy and conservative care versus surgical options.46 Although surgical studies do promote the use of activity modification and physical therapy in the initial treatment, there is no agreed upon “best practice” guidelines when treating athletes’ with anteromedial hip pain and dysfunction.4,17,46-50

For the treatment and management of athletic pubalgia, there is available a position statement put forth by the 2014 British Hernia Society.50 To summarize, this group had recommended that the term athletic pubalgia or sports hernia no longer be used, but instead “inguinal disruption” be used. Also, they had advised that at least a 2 month conservative program consisting of active, supervised physical therapy emphasizing core and lumbopelvic stabilization and strengthening (initially isometric then progressing to eccentric and concentric exercises), cross training, and appropriate injections (not specific, but ilioinguinal nerve blocks were cited) were to be completed prior to any surgical consultation.51 There is a current push in the United States to describe this condition as a Core Muscle injury.52

At different disease stages

In the acute to subacute setting, anteromedial hip disorders may be approached early on with activity modification (for example, avoidance of deep hip flexion and internal rotation to prevent impingement symptoms), rest for a limited time away from the sport, modalities such as ice or heat, a short course of oral anti-inflammatory medications, and an emphasis on an appropriate physical therapy and home exercise program.4,18,19

There is no one recommended rehabilitation program, but most patients with anteromedial hip dysfunction (especially FAI) will have weakness with “hip adduction, abduction, flexion, [and/or] external rotation,” as well as have disturbances with core trunk and lumbopelvic stability and control.4,17,21,46 Hence, the physical therapy prescription should address such strength deficits found on physical exam, accompanied with the goal of improving their lumbopelvic range of motion, proprioceptive training, and reducing pain during sport-specific functional tasks.17 It is very important to include both hip and spine stability exercises before the patient is progressed to sport specific training.17,21,53

If patients do not improve with such management, then their diagnosis should be revisited and further workup done as needed. On the other hand, if their function or progress is limited primarily by pain, then other conservative treatment options are available. For example, for intra-articular lesions (osteochondral or inert layer disorders) such as hip osteoarthritis, FAI, or labral tears, an image guided intra-articular hip injection consisting of a combination of anesthetic with or without corticosteroid may be used to help confirm the diagnosis and in some cases alleviate pain and allow the athlete to continue participation in physical therapy or return to play sooner. They also appear to hold a prognostic value in predicting the need for surgical interventions .2,4 Extra-articular or contractile layer disorders (for example, psoas impingement syndrome) may similarly benefit from an image-guided associated bursa or tendon sheath injection. Initial injections may be performed with anesthetic and corticosteroid, but may be transitioned to more novel treatments such as platelet rich plasma (with or without percutaneous needle tenotomy) if the underlying dysfunction is due to tendinopathy.3,54-57

Chronic disorders may be managed similarly, but may require a longer recovery process and in chronic intra-articular conditions secondary to hip osteoarthritis, ultrasound guided viscosupplementation injections may be used and preferred over repeat corticosteroid injections.58-60

Coordination of care

It is crucial that a team, interdisciplinary approach involving the physician(s), family, athletic trainers, coaches, and physical therapists be used to maximize an athlete’s healing while they are transitioning to returning to play. It is important that communication remains consistent and that the athlete’s diagnosis(e s) be always kept in mind.

Patient & family education

As discussed earlier, education regarding an athlete’s diagnosis, available treatment options, prognosis, injury prevention, and expected return to play to both the athlete and their family or loved ones is important in their recovery process. In addition, at follow up visits or in the training room, gentle reminders should also be used to reinforce avoidance of specific lower extremity motions and the maintenance of a home exercise program to prevent re-injury.

Measurement of Treatment Outcomes including those that are impairment-based, activity participation-based and environmentally-based

Besides monitoring the severity and frequency of pain, efficacy of conservative treatment is based on a number of factors such as improvements in core and focal pelvic girdle weakness, lumbopelvic range of motion, and the ability to return to sports specific tasks with minimal discomfort.

Translation into Practice: practice “pearls”/performance improvement in practice (PIPs)/changes in clinical practice behaviors and skills

Providers should always keep in mind to examine the both the spine and knee as pain patterns at the anteromedial hip may be referred. Initial workup may include imaging of such regions depending upon patient presentation.

The core encompasses the lumbar spine through the thighs. The psoas is the only muscle that has its origin in the spine and crosses to the hip. It works both as a spine stabilizer and hip flexor. All of these elements must be strengthened to return athletes to sports.

Focused hip flexor concentric strengthening can exacerbate symptoms. Focus on strengthening the abductors and core stability. Eccentric and isometric exercises can be initiated as the pain subsides.

Do not view the psoas as being “tight,” think of this being a tone issue. Over stretching of the psoas does not usually work.

Femoral neck stress fractures can mimic hip impingement. Always keep it in mind when a patient with risk factors for a stress fracture has multiple impingement signs encountered on physical exam.

If pelvic floor dysfunction or pain is considered in the differential diagnosis, a more detailed social history inquiring any history of physical or sexual abuse should be elicited, as well as any medical history of psychiatric diagnoses.

4. GAPS IN THE EVIDENCE-BASED KNOWLEDGE

The current literature does not have any double blinded, randomized controlled studies assessing the benefits of structured rehabilitation for anteromedial hip disorders, compared to surgical options.46 There is also no data as to whether such programs also modify the natural history of degenerative joint changes found in symptomatic FAI.18 In addition, it is not known if the addition of ultrasound guided injections (whether intra-articular or percutaneous needle tenotomy with or without platelet rich plasma) may provide outcomes comparable to those found with surgical interventions.

5. CUTTING EDGE/EMERGING AND UNIQUE CONCEPTS AND PRACTICE

The use of musculoskeletal ultrasound to assess for dynamic impingement, tendinosis, and to guide ultrasound guided musculoskeletal interventional procedures has shown promise in the spectrum of conservative treatment among athletes who decline surgery or are not ideal surgical candidates. 39 In addition, platelet rich plasma injections may be beneficial for improving pain encountered with rectus femoris or iliopsoas tendinopathies and potentially for intra-articular conditions such as hip osteoarthritis, when combined with a supervised rehabilitation program.39,58-60

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Author Disclosure

Peter J. Moley, MD
Nothing to Disclose

Richard G. Chang MD, MPH
Foundation for PM&R, Research Grant (Richard S. Materson, MD; ERF New Investigator Grant) paid to institution

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