Female Athlete: Exploring the CORE of Hip Injury Management and Prevention

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INTRODUCTION

Though there is little scientific literature about the role of gender in hip injuries, our clinical experience at the Massachusetts General Hospital Sports Medicine Service suggests that structural and functional anatomy, coupled with distinguishing patterns of movement and hypermobility, are likely risk factors in common regional hip injuries in female athletes.  By enhancing our exam with the most relevant imaging and interventional tools, we can si

ENHANCING THE DIAGNOSTIC EVALUATION

Female athletes frequently present to clinic with hip pain complaints.  Common diagnoses include labral pathology, internal snapping hip syndrome (iliopsoas tendinopathy), and gluteal tendinopathy.  

Evaluation begins with a detailed history and physical examination to distinguish whether the pain generator is intra-articular, extra-articular or referral from the spine or viscera.  Indications of an intra-articular source include mechanical symptoms (locking, clicking, catching, instability) and the ‘C sign’ when the patient places her thumb and forefinger over her anterolateral hip region.  The most specific exam maneuver for intra-articular pain is the hip log roll in a supine position.  The impingement test, resisted straight leg raise, and FABER are other provocative maneuvers.  Extra-articular sources of hip pain can be identified by palpation of the pubic symphysis, adductor tubercle, iliopsoas, ASIS, greater trochanter, piriformis and PSIS.  

It is essential to evaluate static alignment and dynamic biomechanics of the female patient.   The female pelvis is generally broader with greater iliac flare and wider trochanter-to-trochanter distance, with more of an anterior tilt, and the pubic symphysis is shorter and wider. Assessing static standing alignment can reveal evidence of femoral anteversion, genu valgum and pes planus that can predispose females to several lower extremity overuse injuries. 

Regarding dynamic alignment, a simple single leg squat or step down can identify a very common movement pattern in women.  When compared to male athletes, female athletes frequently exhibit a lack of core control, lumbar forward flexion, dominance of hip adduction and internal rotation when performing sports-specific motions, leading to relative valgus angulation at the knee.  Video surveillance illustrates this pattern and mechanism of acute injury.  It is well established that female athletes are at least three times more likely to suffer an ACL injury than male athletes Sutton KM and Bullock JM. Anterior cruciate ligament rupture: difference between males and females. J Am Acad Orthop Surg. 2013 Jan;21(1):41-50. 

Identifying this dominant movement pattern can help to prevent not only ACL injury but several acute and overuse injuries throughout the lower extremity kinetic chain.  Hence we emphasize evaluation of dynamic core and hip strength, focusing on the gluteus medius.  If the gluteus medius is weak, the dynamic hip, knee, ankle alignment is suboptimal and can be the primary imbalance that leads to the above at-risk movement pattern.

We also recommend evaluating the female athlete for hypermobility, including measuring musculotendinous flexibility and ligamentous laxity.  Beighton criteria help us identify hypermobility, quite common in female athletes.  (Day H et al. Hypermobility and dance: a review. Int J Sports Med. 2011 Jul;32(7):485-9).  Hypermobile athletes can put increased load throughout the hip joint surfaces as well as the extra-articular muscles that must work harder to control the excess motion.  Hypermobility is a risk factor for internal snapping hip syndrome; estimates vary, but some suggest half of adolescent dancers have this diagnosis, though it may be asymptomatic.  Moreover, a snapping iliopsoas tendon may be a potential risk factor for developing an anterosuperior acetabular labral tear.

Through a focused hip exam and global dynamic evaluation, we arrive at a working diagnosis and an understanding of the biomechanics that place the athlete at risk for injury.  We believe that gluteal weakness resulting in this movement pattern, in conjunction with hypermobility, may lead to increased risk for many injuries common in female athletes, including acetabular labral pathology, iliopsoas tendinopathy, and gluteal tendinopathy.  

These injuries can have serious impacts on the patient’s life, including pain and functional limitations impacting work, school, exercise/recreation/sports and community engagement. 

IMAGING STUDIES AND IMAGE-GUIDED INJECTIONS

Imaging studies can provide additional information to improve diagnostic accuracy.  Plain radiographs can identify bony abnormalities associated with intra-articular pain, such as femoral acetabular impingement and acetabular dysplasia, but they are poor in identifying initial stages of hip osteoarthritis.  

Magnetic resonance arthrography (MRA) is more sensitive than standard MRI in revealing intra-articular abnormalities, but it produces twice the number of false positives. There is a reasonably high incidence of asymptomatic acetabular labral tears and gluteal tendon abnormalities that may not be clinically significant.  For example, Register et al demonstrated labral pathology in 69% of their cohort of asymptomatic patients of average age 39 (Register B et al.  Prevalence of abnormal hip findings in asymptomatic participants: a prospective, blinded study. Am J Sports Med. 2012 Dec;40(12):2720-4). Also, MR is relatively poor in evaluating chondral injury.  

Diagnostic injections are emerging as the preferred tool in distinguishing intra-articular versus extra-articular sources of pain.  Byrd and Jones demonstrated that positive response to intra-articular injection is the most reliable indicator of intra-articular abnormality seen at arthroscopy.  In this study, injection provided better diagnostic accuracy when compared to clinical assessment, MRI and MRA (Byrd JW and Jones KS. Diagnostic accuracy of clinical assessment, magnetic resonance imaging, magnetic resonance arthrography, and intra-articular injection in hip arthroscopy patients.  Am J Sports Med. 2004 Oct-Nov;32(7):1668-74.

Symptoms and physical examination of iliopsoas tendinopathy and bursitis can mimic intra-articular pain due to the close anatomic relationship of the tendon as it courses over the anterior hip capsule adjacent to the anterosuperior labral complex.  A diagnostic ultrasound-guided iliopsoas bursa injection can distinguish whether this is the primary source of pain.  Accurate intra-articular hip injection can be performed with either fluoroscopic or ultrasound guidance

( Smith J and Hurdle MF. Office-based ultrasound-guided intra-articular hip injection:

technique for physiatric practice. Arch Phys Med Rehabil 2006;87:296–8).  

COMMON DIAGNOSES IN FEMALE ATHLETES

HIP LABRAL PATHOLOGY

Labral pathology is the most common source of intra-articular hip pain in female athletes. The labrum provides shock absorption, stability, and a joint suction seal that ensures joint lubrication and cartilage nutrition. A tear that disrupts this suction seal may decrease hydrostatic pressure within the joint and increase the compressive load on the chondral surface.  This may initiate the degenerative cascade and lead to early onset hip osteoarthritis. 

Labral tears have been demonstrated to occur more frequently in women. (Hunt D et al. Acetabular labral tears of the hip in women  Phys Med Rehabil Clin N Am. 2007 Aug;18(3):497-520).  Risk factors include gymnastics, dance, and soccer, due to the extremes of hip motion.  And there is increased incidence of acetabular dysplasia, internal snapping hip syndrome, and hypermobility in women.  Females present with anterior hip and groin pain worsened with impact exercise, cutting and pivoting.  Provocative exam maneuvers can include positive impingement test and resisted straight leg raise.  Athletes may demonstrate the movement pattern described above with dominance of hip internal rotation and adduction and relative weakness of the hip abductors.  This pattern plus/minus hypermobility may place increased force through the labrum and predispose the hip to pathology of the anterosuperior labral tissue.  

Treatment consists of a trial of nonsteroidal anti-inflammatories and physical therapy focused on core and hip strengthening and stabilization to diminish the load placed through the labrum and articular surfaces.  Neuromuscular training can help to modify the dynamic movement to limit recurrent hip internal rotation.  The labrum is primarily avascular, so the healing potential is suboptimal.  Some athletes will require surgical intervention if conservative care fails.  This can include arthroscopic labral repair, debridement and correction of bony abnormalities.

ILIOPSOAS TENDINOPATHY, INTERNAL SNAPPING HIP SYNDROME

Internal snapping hip syndrome occurs when the iliopsoas tendon translates over the iliopectineal eminence of the pelvis, the femoral head, or a slip of iliopsoas muscle.  Internal snapping hip is present in 10% of the population.  It is common in adolescent ballet dancers and is frequently seen in hypermobile females. It can become a source of pain due to tendinopathy and/or development of iliopsoas bursitis.  It has been reported that 50% of internal snapping hip is associated with intra-articular pathology and may be one risk for development of labral pathology (Ilizaliturri VM and Camacho-Galindo J.  Endoscopic treatment of snapping hips, iliotibial band, and iliosoas tendon. Sports Med Arthrosc. 2010 Jun;18(2):120-7).  Patients present with tenderness over the tendon and pain with resisted hip flexion.  Internal snapping can be reproduced on examination with transitioning the hip from flexion and external rotation to extension and internal rotation.  Musculoskeletal ultrasound can contribute to diagnosing tendinopathy and/or bursitis.  Ultrasound-guided injection performed into the bursa region can confirm diagnosis and provide therapeutic relief.  

Treatment is focused on conservative care with skilled physical therapy, including deep tissue massage, strength training and flexibility.  In patients refractory to PT and activity modification, surgery to lengthen the iliopsoas tendon can be performed.

GLUTEAL TENDINOPATHY

Peritrochanteric pain occurs four times as often in females, with an increasing incidence in female athletes.  The female’s wider pelvis and femoral anteversion can increase the forces transmitted through the gluteus medius and minimus entheses at the greater trochanter.  Traditionally, we have diagnosed patients with lateral hip pain and focal trochanteric tenderness as having trochanteric bursitis.  Treatment included local bursal corticosteroid injection, repeated if pain recurrs.  Corticosteroids may actually harm the tissue and propagate further tissue degeneration.  Imaging studies have demonstrated that patients with peritrochanteric hip pain frequently demonstrate gluteus medius and minimus tendinopathy rather than bursal inflammation (Bird PA et al. Prospective evaluation of magnetic resonance imaging and physical examination findings in patients with greater trochanteric pain syndrome.  Arthritis Rheum. 2001 Sep;44(9):2138-45).  As a result, we perform trochanteric bursa injections only if confirmed by ultrasound or MR.  We find ultrasound-guided injections to be most efficacious.  

Treatment emphasizes progressive resistance strength training focused on the gluteus medius and minimus.  We favor exercises that isolate the gluteus medius muscle fibers from the tensor fascial lata, such as the clamshell, sidestep and unilateral bridge. Individualized programs focus at optimizing core and hip stabilization.  Motor retraining with correction of the female dominant movement pattern is critical once strength training is underway.  Regenerative injection therapy such as platelet rich plasma injection (an experimental intervention currently lacking level 1 scientific evidence) can be utilized if conservative treatment fails.  In refractory cases, surgery may be necessary, including bursectomy with or without ITB lengthening, open or endoscopic repair of the gluteus medius.  

CONCLUSION 

Female athletes exhibit characteristic static pelvic and lower extremity alignment and dynamic movement that can put them at risk for certain hip region injuries.  Fine-tuning the clinical exam to explore at-risk movement patterns and hypermobility leads to a precise diagnosis and comprehensive approach to treatment.   When the origin of pain remains uncertain, imaging studies, especially MRA, and ultrasound-guided injections are superior means of distinguishing intra- from extra-articular pain generators.  Through treatments focused on strengthening and stabilization of the core and hip abductors, we offer effective treatment and an approach to preventing future injuries.

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Hip and Lumbopelvic Pain in the Female Athlete 

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Kelly McInnis, D.O.

February 13, 2014

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ABOUT THE AUTHOR

Kelly McInnis, D.O., is Associate Program Director of the Spaulding/Harvard Medical School PM&R sports medicine fellowship program, head team physician for Suffolk University, and a team consultant for the New England Patriots, Boston Bruins, Boston Red Sox, New England Revolution, and local colleges and high schools.  Board certified in PM&R and Sports Medicine, she has specialized training in musculoskeletal ultrasound and has a clinical interest in overuse injuries in the endurance athlete with special considerations in the female athlete.

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