Athletic Hip Injuries

Lynch, T. Sean MD; Bedi, Asheesh MD; Larson, Christopher M. MD

Journal of the American Academy of Orthopaedic Surgeons:
doi: 10.5435/JAAOS-D-16-00171
Review Article
Abstract

Historically, athletic hip injuries have garnered little attention; however, these injuries account for approximately 6% of all sports injuries and their prevalence is increasing. At times, the diagnosis and management of hip injuries can be challenging and elusive for the team physician. Hip injuries are seen in high-level athletes who participate in cutting and pivoting sports that require rapid acceleration and deceleration. Described previously as the “sports hip triad,” these injuries consist of adductor strains, osteitis pubis, athletic pubalgia, or core muscle injury, often with underlying range-of-motion limitations secondary to femoroacetabular impingement. These disorders can happen in isolation but frequently occur in combination. To add to the diagnostic challenge, numerous intra-articular disorders and extra-articular soft-tissue restraints about the hip can serve as pain generators, in addition to referred pain from the lumbar spine, bowel, bladder, and reproductive organs. Athletic hip conditions can be debilitating and often require a timely diagnosis to provide appropriate intervention.

Author Information

From Columbia Orthopaedics, the Center for Shoulder, Elbow and Sports Medicine, Columbia University Medical Center, New York, NY (Dr. Lynch), the Department of Orthopaedic Surgery, MedSport, University of Michigan Medical School, Ann Arbor, MI (Dr. Bedi), and the Minnesota Orthopedic Sports Medicine Institute at Twin Cities Orthopedics, Edina, MN (Dr. Larson).

Dr. Bedi or an immediate family member serves as a paid consultant to Arthrex; has stock or stock options held in A3 Surgical; and serves as a board member, owner, officer, or committee member of the American Orthopaedic Society for Sports Medicine. Dr. Larson or an immediate family member serves as a paid consultant to Smith & Nephew and A3 Surgical; has stock or stock options held in A3 Surgical; and has received research or institutional support from Smith & Nephew. Neither Dr. Lynch nor any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this article.

Received February 27, 2016

Accepted July 03, 2016

Article Outline
Back to Top | Article Outline

JAAOS Plus Webinar

Join Dr. Lynch, Dr. Bedi, and Dr. Larson for the interactive JAAOS Plus Webinar discussing “Athletic Hip Injuries,” on Tuesday, April 18, 2017, at 8 pm Eastern Time. The moderator will be Rick W. Wright, MD, the Journal's Deputy Editor for Sports Medicine topics. Sign up now at http://www.aaos.org/coursecalendar, Product Code 1702227B

The hip joint is a model of stability because it anchors the pelvis and lower appendicular skeleton. This anchoring is accomplished through the sacroiliac and femoroacetabular joints as well as through a complex arrangement of numerous muscles, tendons, and ligaments that cross these joints. With this support in place, hip motion is controlled by not only the thigh muscles, but also the body’s core (including the low lumbar musculature), with additional support from the adductors and gluteus muscles. This architecture allows the hip to withstand six to eight times a person’s body weight during walking or running. It takes a large amount of force to damage a healthy hip and its surrounding muscles; however, the stresses that an athlete places on his or her body, combined with the increased prevalence of abnormal hip anatomy in certain athletes, can put this joint and the surrounding soft tissues at risk of injury.

Historically, athletic hip injuries were diagnosed as recalcitrant groin pulls or hip flexor pulls, and in some instances, would prematurely end an athlete’s playing career. Over the last 10 to 15 years, these injuries have become increasingly recognized as a source of disability through an improved understanding of these athletic injuries with better physical examination skills and imaging modalities.1,2 This has resulted in the development of disease-specific treatment regimens to help athletes return to sport. Here, we focus on the sports hip triad.3 This injury pattern consists of intra-articular hip injuries, including femoroacetabular impingement (FAI) and labral injuries, with associated abnormalities to the adductor and rectus abdominis muscles, which share a common sheath and attachment—the pubic symphysis. Changes to the tension of the rectus and adductor muscles can place the respective muscle at risk for injury, and these muscle imbalances across the pelvis can lead to athletic pubalgia and osteitis pubis, which can be associated with intra-articular injury and motion-limiting FAI. Team physicians must be familiar with athletic hip injuries to ensure timely diagnoses and treatment.

Back to Top | Article Outline

Hip Injuries Across Sports

Hip injuries account for 6% of sports injuries, and the prevalence is increasing.4-7 These injuries have been investigated across several individual professional sports associations. Feeley et al3 evaluated hip and labral injuries in the National Football League (NFL) between 1997 and 2006. These injuries made up 3.1% of all injuries, and players returned to sport within 2 weeks. Hip flexor strain was the most common diagnosis, and intra-articular injuries resulted in the most time lost from competition (94.2 days). More recently, Epstein et al8 reviewed intra-articular hip injuries in the National Hockey League. These injuries made up 10.6% of all hip and groin injuries and resulted in a mean of eight missed games; goaltenders were noted to be at particular risk. Jackson et al9 analyzed hip injuries in the National Basketball Association over 24 seasons. These injuries made up >14% of athletics-related injuries during this time. Unlike the hip/groin injuries common in the NFL and in the National Hockey League, extra-articular strains and contusions and quadriceps injuries are most commonly reported in the National Basketball Association. Athletes with these injuries missed approximately 1 week of play.

Back to Top | Article Outline

Layered Approach Concept

When evaluating an athlete with hip pain, it is important to recognize the root of the pathology separate from the pain source. The layered approach has been developed as an algorithmic methodology designed to help the clinician better understand the hip and delineate the source of pathology.10 The hip has been divided into four layers: layer 1 is the osseous layer; layer 2 is the capsuloligamentous layer; layer 3 is the myotendinous layer; and layer 4 is the neurokinetic layer.

The first layer consists of the femur, pelvis, and acetabulum. Abnormalities in this layer can be divided into three distinct categories: static overload, dynamic impingement, and dynamic instability. Hip and pelvic pain can arise when the required functional range of motion of the hip for a particular athletic activity is greater than that which the athlete’s anatomy allows. FAI is a motion-limiting disorder that can lead to dynamic impingement, with a resulting compensatory motion or stress about the sacroiliac joint, pubic symphysis, and lumbar spine. Attempts to increase flexion and internal rotation can lead to dynamic instability, with anterior contact between the cam deformity and the anterosuperior acetabulum at terminal internal rotation. This instability can cause levering of the femoral head posteriorly, with a resulting posterior hip subluxation or dislocation and concomitant labral and cartilage damage11 (Figure 1).

Layer 2 is the capsuloligamentous layer, which includes the labrum, joint capsule, ligamentous/capsular complex, and ligamentum teres. The previously described mechanical stresses from layer 1 can lead to asymmetric wear of the chondral surfaces of the femoral head and/or acetabulum, as well as injuries to the labrum and ligamentum teres. The structural morphology of layer 1 and the demands of the athlete’s sport often can be used to predict the injury pattern in layer 2.12

Layer 3 is the myotendinous layer and includes all the muscles about the hemipelvis and the lumbosacral and pelvic floor regions. Dynamic impingement from a cam deformity in layer 1 causes increased strain on the sacroiliac joint, pubic symphysis, and ischium. Secondary strain then is placed on the muscles that attach to the pelvic structures and can lead to various enthesopathies and/or tendinopathies. Layer 4, the neurokinetic layer, includes the thoracolumbosacral plexus, lumbopelvic tissues and lower extremity structures that are responsible for the communication, timing, and sequencing of the kinetic chain. This layer also serves as the neuromuscular link that dictates functional control of the entire segment as it moves in space. This layer includes the ilioinguinal, iliohypogastric, and genitofemoral nerves, as well as a variety of other mechanoreceptors and nociceptors. In essence, this layer is responsible for the posture and the proprioception of the pelvis over the femur.

Back to Top | Article Outline

Athletic Hip Injuries

Pain about the groin or pelvis in athletes can be challenging to diagnose and manage. Diagnosis can be difficult because pain can be referred to or from several different locations, including the lower back/lumbar spine, abdominal and pelvic viscera, genitourinary structures, and hip and knee joints. In the past, injuries to this area could lead to premature retirement from the athlete’s sporting activity if rehabilitation was not successful.13 Underlying causes of athletic hip and groin injuries can be divided into four broad categories: adductor strains, osteitis pubis, athletic pubalgia, and intra-articular hip pathology, such as FAI.

Back to Top | Article Outline
Adductor Strains

The adductor muscle complex includes the adductor longus, adductor magnus, and adductor brevis muscles, as well as the gracilis, obturator externus, and pectineus muscles. However, the adductor longus muscle frequently is the source of pathology and symptoms in athletes.14 In professional soccer players, adductor longus injuries represented 23% of all muscle injuries, resulting in a mean 2 weeks of lost playing time and a reinjury rate of 18%.15 In athletes with reinjuries, return to play took considerably longer than the recovery time from their original injury, which stresses the importance of rehabilitation that emphasizes the correction of any predisposing factors that might put the athlete at risk for injury, including muscle tightness, weakness, or imbalances across the pelvis.16

The adductor muscle complex is frequently susceptible to injuries during sporting activity from large mechanical loads placed onto the small tendon of the adductor longus during muscle contraction.14 These injuries occur during eccentric contraction at the myotendinous unit or fibrocartilaginous insertion of the adductor tendon on the pubic bone, known as the adductor enthesis. Athletes report aching groin or medial thigh pain that is exacerbated with resisted adduction and passive stretching of the adductors. Athletes with an injury at the adductor enthesis have pain on palpation at or near the origin on the pubic bone (Figure 2). Myotendinous injuries present with pain that is further distal. Reduced adductor muscle strength, measured with the athlete lying on the side with the hip in neutral rotation, and the loss of hip range of motion have been associated with an increased risk of subsequent strain injury.16

Back to Top | Article Outline
Osteitis Pubis

Osteitis pubis is a painful overuse stress injury of the pubic symphysis that can cause lower abdominal pain or groin pain secondary to excessive strain and motion of the joint. The pubic symphysis acts as a fulcrum for force generated at the anterior pelvis. The rectus abdominis tendon and the three adductor tendons attach to the fibrocartilage plate of the pubic symphysis to provide anterior pelvic stabilization. During core rotation and extension, these muscles act as antagonists; the rectus elevates the pelvis, and the adductors depress it. Injury to any of these muscles increases stress that can alter symphyseal biomechanics, ultimately causing a stress injury/reaction of the pubic bone. Later degeneration of the cartilage at the pubic symphysis also can result from these stresses.

An overlap of patient presentation and physical examination findings has been observed in athletic pubalgia, but a distinguishing feature is that pain can be elicited with palpation over the pubic symphysis and during a positive spring test (Figure 3). It is critical to ascertain whether the pain on palpation is truly a typical limiting pain for the athlete because tenderness in this region is common. In the setting of chronic osteitis pubis, characteristic radiographic findings include lytic changes at the pubic symphysis, sclerosis, and widening of the symphysis (Figure 4). MRI shows subchondral bone marrow edema with bilateral involvement that is more prominent on the affected side.17 This finding also is relatively frequent in asymptomatic athletes.

Back to Top | Article Outline
Athletic Pubalgia/Core Muscle Injury

Athletic pubalgia is another source of hip pain that can be debilitating for the athlete. This condition is commonly referred to as a sports hernia or core muscle injury. In general, no hernia is seen with these injuries, but weakening or tearing of the abdominal wall is present. Affected athletes have unilateral or bilateral lower abdominal pain that can radiate toward the perineum and proximal adductors during sporting activities. Athletes participating in sports that require repetitive pivoting and cutting (eg, ice hockey, soccer, American and Australian rules football) are susceptible to these injuries.4,18,19 A classic finding is pain present with activity that prevents the athlete from playing at full potential but ceases with inactivity. Physical examination findings include pain with palpation over the pubis and the abdominal obliques and/or rectus abdominis insertion as well as occasional pain on palpation at the adductor longus tendon origin at or near the pubic symphysis. Pain also is exacerbated with resisted sit-ups at the inferolateral edge of the distal rectus abdominis and with resisted adduction20 (Figure 5). MRI can show a cleft sign at the rectus abdominis/adductor aponeurosis, about the anterior pelvis; however, these imaging findings are not infrequent in asymptomatic athletes21 (Figure 6).

Back to Top | Article Outline

Management

Management of athletic hip injuries typically begins with nonsurgical care, consisting of cessation or modification of the offending sport, anti-inflammatory medications, and physical therapy. Rehabilitation should emphasize core strengthening and stabilization and postural retraining with normalization of the dynamic relationship between the hip and pelvic muscles. Local injections can be helpful in some cases to allow high-level athletes to continue to participate during the season. Aggressive stretching to improve range of motion should be avoided to prevent aggravation of hip pain in athletes with underlying FAI. Other exercises that should be avoided include deep hip flexion and low repetition and heavyweight strength training. After the athlete is pain free, a gradual return to play can be initiated.

Back to Top | Article Outline
Adductor Strains

In addition to first-line treatment strategies, adjuncts to the nonsurgical care of adductor injuries can include entheseal pubic cleft injections after a period of rest, anti-inflammatory drugs, and physical therapy. The injection is directed into the adductor enthesis (Figure 7). Schilders and colleagues13,22 investigated the role of such injections in elite and recreational athletes. In elite athletes, the investigators found that individuals with chronic adductor-related groin pain and normal MRI findings had no recurrence of pain at 1 year.13 However, symptoms recurred at a mean 5 weeks after injection in athletes who had evidence of enthesopathy on MRI.13 This finding suggests that athletes with a chronic adductor injury but no evidence of enthesopathy on MRI have early, mild disease that could resolve with nonsurgical treatment, including corticosteroid injection. However, corticosteroid injection appears to be less effective in patients with more advanced adductor disease. In a separate study of recreational athletes with adductor related groin pain, the same injection produced successful results despite evidence of enthesopathy on MRI.22 This conclusion emphasizes the importance of considering the athlete’s level when treating such an injury and suggests that injections can be used for diagnostic purposes or to provide short-term pain relief.

Most adductor injuries are low-grade strains or partial tears that generally are amenable to nonsurgical care. In athletes who have sustained complete ruptures of the proximal adductor longus, surgical reattachment has allowed a return to play but with the added cost of extended time out for healing and recovery.23,24 In a study of NFL players with adductor longus tendon ruptures treated nonsurgically, Schlegel et al25 reported that the players returned to play in half the time (ie, an average of 6 weeks) compared with surgical reattachment (12 weeks). For athletes with recalcitrant adductor enthesopathy, however, selective adductor release has been found to be beneficial. Schilders et al26 concluded that selective partial adductor release in 43 professional athletes provided considerable pain relief. All but one of the athletes returned to their preinjury level of sport at approximately 2 months.

Back to Top | Article Outline
Osteitis Pubis

Corticosteroid injections also have been useful adjunctive treatments that provide relief of pain associated with osteitis pubis and accelerate an athlete’s return to play.27,28 Athletes who received corticosteroid injections into the symphyseal cleft and those who received injections within 2 weeks of diagnosis had the best results.28 Nonsurgical care is generally successful in relieving symptoms; however, return to play can take time, and pain-free play can take even longer. Verrall et al29 investigated pubic bone stress injuries in professional Australian football players. They found that 89% of athletes were able to return to play by the next football season, 20 to 24 weeks after the diagnosis and initiation of treatment. Only 41% of athletes were symptom free, however. By the end of the first season after injury, 67% of all athletes had no symptoms, and after the second season (ie, 24 months after diagnosis), 81% were symptom free.

Nonsurgical treatment fails in approximately 5% to 10% of athletes, who then require surgical treatment.30 For the athletic population, surgical options include pubic symphyseal fusion, débridement of the pubic symphysis through open or endoscopic approaches, wedge resections, or surgical treatment of associated symptomatic FAI and/or athletic pubalgia31-34 (Table 1). Surgical indications are not well defined, and considerable geographic differences in treatment and diagnosis exist. Some clinicians consider osteitis pubis to be an isolated entity, whereas others attribute the symptoms to associated FAI and/or athletic pubalgia. Procedures directed at the pubic symphysis alone have been described in small series and can have important long-term complications, such as hemospermia, scrotal swelling, and stress fractures through the symphyseal arthrodesis.31

Back to Top | Article Outline
Athletic Pubalgia

Moderate to severe symptoms of athletic pubalgia rarely improve with nonsurgical care and eventual surgical repair for symptom relief is typically required to allow the athlete to return to play.35,36 Some factors to remember regarding treatment include the level at which the athlete is competing and the timing of the sports season. During the season, if the athlete can continue to function, then the previously described strategies can be used, along with a potential corticosteroid injection for immediate pain relief to help the athlete get to the off-season, when surgical intervention can be considered without substantial time lost from sport. Surgery should be considered for the in-season athlete who cannot continue despite nonsurgical measures (Figure 8).

Surgical options are numerous, and no consensus on a preferred surgical technique has been observed in the literature. Surgical procedures are divided into three general categories: open repair with or without mesh reinforcement, laparoscopic repair with mesh, and broad pelvic floor repair with possible adductor release/repair and neurectomy. Primary repairs can be subdivided further into a modified Bassini-type repair with or without adductor releases and a minimal repair with decompression of the genital branch of the genitofemoral nerve. Athletes are able to return to play at a rate of 80% to 100% regardless of the repair type6,20,34,37-42 (Table 2).

Meyers et al20 described a primary repair in which the inferolateral border of the rectus abdominis is repaired to the pubis and the inguinal ligament to provide stability to the rectus. For athletes with adductor pathology and pain, a repair or release also can be performed to help restore core muscle balance. In this series of high performing athletes, approximately 88% were performing at or above their preinjury level within 3 months. This percentage increased to 96% at 6 months. The minimal repair technique of the transversalis fascia has been described by Muschaweck and Berger.39,43 This technique focuses on the decompression of the genital branch of the genitofemoral nerve with tension-free repair of the posterior inguinal wall deficiency or defect. Athletes undergoing the minimal repair procedure can resume running and cycling on postoperative day 2, can begin sports-specific training on postoperative day 3 or 4, and can train fully on postoperative day 5. This accelerated return to play is attributed to the tension-free repair that enables athletes to return to play within 2 weeks.

Postoperative rehabilitation varies by surgical technique and surgeon preference, but programs should focus on a step-wise progression of exercise activity, with a focus on core and lower extremity strength, stability, flexibility, and balance. Emphasis should be placed on achieving proper muscle activation, and recruitment-pattern training is essential to proper recovery. Walking can be initiated early, and light jogging can be started by 3 to 4 weeks postoperatively. In our experience, athletes generally can return to sport within 6 to 8 weeks of surgery, regardless of the approach used.

Back to Top | Article Outline

Femoroacetabular Impingement and Athletic Hip Injuries

The details of FAI anatomy, pathomechanics, and treatment options are beyond the scope of this article, but the presence of FAI has been implicated in the development of the athletic hip injuries described here. FAI is a condition of the hip in which abnormal, repetitive contact occurs, most commonly between the anterolateral femoral head-neck junction and the anterolateral rim of the acetabulum. There are two primary forms of FAI: cam type and pincer type. Cam deformities have an osteochondral asphericity at the femoral head-neck junction that leads to a loss of femoral offset. Pincer deformities have an overcoverage of the femoral head by the acetabulum. These deformities can exist independently or in a mixed pattern that can cause a cascade of intra-articular breakdown, including but not limited to disruption of the chondrolabral junction.

The prevalence of FAI has been found to be substantially higher in collegiate football players than in the general population.44 A total of 67 male athletes (134 hips) were evaluated radiographically, and 95% of hips had at least one radiographic finding of FAI; 77% had more than one sign. A total of 78% had at least one sign of cam deformity, and 66% had at least one sign of pincer impingement. In ice hockey players, 39% of collegiate and professional players were found to have considerably higher alpha angles.45 Finally, in male and female professional soccer players, 72% of males and 50% of females had at least one radiographic finding of FAI. Despite exhibiting no current symptoms, 50% of male soccer players and 25% of female soccer players reported a previous groin or hip injury.46

As described previously in the section on the layered approach, the loss of internal rotation from the presence of a cam deformity or retroverted neck causes abnormal contact with the acetabular rim earlier in the arc of motion. This block to further motion can initiate impingement and cause injury to the labrum and adjacent articular cartilage, which can lead to osteoarthritis.47 The loss of motion also produces compensatory hip and pelvic dysfunction through increased extra-articular pelvic motion. The compensatory forces place more stress on the pelvic stabilizers and ultimately can cause a breakdown of the pelvic soft-tissue structures, potentially leading to the athletic hip injuries described previously.

In a prospective study of athletes with long-standing adductor longus tendinopathy, Weir et al7 found that 64 of 68 hips (94%) demonstrated radiographic evidence of FAI; cam morphology was found in 27 hips (40%). Only nine hips (13%), however, exhibited a positive result on the anterior impingement test.

Groin injuries and osteitis pubis have been associated with a loss of internal hip rotation in Australian football players.48 Larson et al49 evaluated this association in a subset of elite athletes with symptomatic intra-articular hip pathology and extra-articular core muscle injury. The authors found that, when intra-articular and extra-articular pain was present, isolated surgical treatment of athletic pubalgia symptoms resulted in 25% of athletes returning to play. When arthroscopic FAI correction alone was performed, 50% of athletes were able to return to sports, but when both pathologies were addressed concurrently or in separate settings, the rate of return to sport was 85% to 93%. Hammoud et al50 also investigated this overlap of diagnoses in professional athletes. Players with isolated athletic pubalgia surgery could not return to play because of persistent pain until they underwent additional treatment for FAI. Conversely, in >60% of athletes, the symptoms of athletic pubalgia resolved with FAI treatment. This finding emphasizes the importance of counseling the athlete about arthroscopic or open FAI correction and the potential need for an athletic pubalgia procedure if symptoms do not resolve. In the high-level athlete, considerations should be made for staged or simultaneous surgical corrections of FAI and athletic pubalgia for a more predictable return to sport with minimal time lost.

The connection between FAI and athletic hip injuries has been confirmed not only clinically, but also biomechanically and radiographically. Birmingham et al51 verified the association between dynamic cam impingement and athletic pubalgia. Cam lesions were simulated in 12 hips from six fresh-frozen cadavers by implanting a dome-shaped wood button with a 5-mm dome height and a base diameter of 25 mm on the femoral head-neck junction at the 1:30 position. A custom loading jig that placed the leg in 90° of flexion with neutral adduction and internal rotation was applied to the femur for the simulation. This investigation supported previous theories that cam impingement causes rotational motion at the pubic symphysis after bony contact. This motion occurred in all planes, but most importantly in the transverse plane. The investigators found that this motion was present in the native hip as well as in the hip with simulated cam lesion, and they also found 35% more motion at the pubic symphysis with the cam lesion. This repetitive loading of the pubic symphysis is a known precursor of athletic pubalgia and can be a source of pain in athletes with limited hip motion.

Economopoulos et al52 retrospectively reviewed 43 athletes who underwent surgical intervention (56 procedures) for athletic pubalgia. Plain radiographs were assessed for signs of FAI, and 86% of patients had at least one sign of FAI. The average alpha angle was 66.7°, 83.7% of athletes had a cam deformity, and 28% had pincer pathomorphology. In addition, a previous study assessing long-standing adductor tendinopathy found that 94% of patients had radiographic evidence of FAI.7 Larson et al53 evaluated 125 NFL prospects (239 hips) who had a radiographic evaluation at the NFL Scouting Combine. Of all athletes, 90% (87% of hips) had at least 1 radiographic sign of FAI. The players were separated based on the presence of hip symptoms (75 symptomatic, 164 asymptomatic). The authors found that an increased alpha angle on plain radiography was the only predictor of athletic hip/groin pain.

Back to Top | Article Outline

Summary

Athletic hip injuries can be a diagnostic challenge, and defining the ideal treatment strategy can test even the most seasoned sports medicine provider. Within the past 15 years, not only has recognition of hip pathology increased tremendously, but the treatment modalities to return athletes to the field safely and quickly also have improved. In general, management of athletic hip injury begins with nonsurgical measures, such as temporary activity modification, anti-inflammatory medications, and rehabilitation focused on core strengthening and pelvic balance restoration. Surgical intervention is reserved for athletes in whom nonsurgical treatment fails. The recognition of FAI and its biomechanical relationship to compensatory disorders about the hip and pelvis are paramount for achieving a successful clinical outcome and minimizing the disability time for athletes. FAI is the most common cause of prearthritic hip pain in the nondysplastic hip and appears to have a strong association with a multitude of hip and pelvis disorders typically seen in athletes.

Back to Top | Article Outline

References

Evidence-based Medicine: Levels of evidence are described in the table of contents. In this article, references 6, 15, and 16 are level II studies. References 1, 41, 44, and 45 are level III studies. References 7, 11-13, 18-21, 25-35, 37-40, 43, 47-50, 52, and 53 are level IV studies. References 23 and 24 are level V expert opinion.

References printed in bold type are those published within the past 5 years.

1. Philippon MJ, Maxwell RB, Johnston TL, Schenker M, Briggs KK: Clinical presentation of femoroacetabular impingement. Knee Surg Sports Traumatol Arthrosc 2007;15(8):1041–1047.
2. Lynch TS, Terry MA, Bedi A, Kelly BT: Hip arthroscopic surgery: Patient evaluation, current indications, and outcomes. Am J Sports Med 2013;41(5):1174–1189.
3. Feeley BT, Powell JW, Muller MS, Barnes RP, Warren RF, Kelly BT: Hip injuries and labral tears in the national football league. Am J Sports Med 2008;36(11):2187–2195.
4. Anderson K, Strickland SM, Warren R: Hip and groin injuries in athletes. Am J Sports Med 2001;29(4):521–533.
5. Garvey JF, Read JW, Turner A: Sportsman hernia: What can we do? Hernia 2010;14(1):17–25.
6. Kluin J, den Hoed PT, van Linschoten R, IJzerman JC, van Steensel CJ: Endoscopic evaluation and treatment of groin pain in the athlete. Am J Sports Med 2004;32(4):944–949.
7. Weir A, de Vos RJ, Moen M, Hölmich P, Tol JL: Prevalence of radiological signs of femoroacetabular impingement in patients presenting with long-standing adductor-related groin pain. Br J Sports Med 2011;45(1):6–9.
8. Epstein DM, McHugh M, Yorio M, Neri B: Intra-articular hip injuries in national hockey league players: A descriptive epidemiological study. Am J Sports Med 2013;41(2):343–348.
9. Jackson TJ, Starkey C, McElhiney D, Domb BG: Epidemiology of hip injuries in the National Basketball Association: A 24-year overview. Orthop J Sports Med 2013;1(3):2325967–113499130.
10. Poultsides LA, Bedi A, Kelly BT: An algorithmic approach to mechanical hip pain. HSS J 2012;8(3):213–224.
11. Krych AJ, Thompson M, Larson CM, Byrd JW, Kelly BT: Is posterior hip instability associated with cam and pincer deformity? Clin Orthop Relat Res 2012;470(12):3390–3397.
12. Hammoud S, Bedi A, Voos JE, Mauro CS, Kelly BT: The recognition and evaluation of patterns of compensatory injury in patients with mechanical hip pain. Sports Health 2014;6(2):108–118.
13. Schilders E, Bismil Q, Robinson P, O’Connor PJ, Gibbon WW, Talbot JC: Adductor-related groin pain in competitive athletes: Role of adductor enthesis, magnetic resonance imaging, and entheseal pubic cleft injections. J Bone Joint Surg Am 2007;89(10):2173–2178.
14. Renström P, Peterson L: Groin injuries in athletes. Br J Sports Med 1980;14(1):30–36.
15. Ekstrand J, Hägglund M, Waldén M: Epidemiology of muscle injuries in professional football (soccer). Am J Sports Med 2011;39(6):1226–1232.
16. Tyler TF, Nicholas SJ, Campbell RJ, McHugh MP: The association of hip strength and flexibility with the incidence of adductor muscle strains in professional ice hockey players. Am J Sports Med 2001;29(2):124–128.
17. Mullens FE, Zoga AC, Morrison WB, Meyers WC: Review of MRI technique and imaging findings in athletic pubalgia and the “sports hernia”. Eur J Radiol 2012;81(12):3780–3792.
18. Susmallian S, Ezri T, Elis M, Warters R, Charuzi I, Muggia-Sullam M: Laparoscopic repair of “sportsman’s hernia” in soccer players as treatment of chronic inguinal pain. Med Sci Monit 2004;10(2):CR52–CR54.
19. Irshad K, Feldman LS, Lavoie C, Lacroix VJ, Mulder DS, Brown RA: Operative management of “hockey groin syndrome”: 12 years of experience in National Hockey League players. Surgery 2001;130(4):759–764, discussion 764-766.
20. Meyers WC, Foley DP, Garrett WE, Lohnes JH, Mandlebaum BR; PAIN (Performing Athletes with Abdominal or Inguinal Neuromuscular Pain Study Group): Management of severe lower abdominal or inguinal pain in high-performance athletes. Am J Sports Med 2000;28(1):2–8.
21. Zoga AC, Kavanagh EC, Omar IM, et al: Athletic pubalgia and the “sports hernia”: MR imaging findings. Radiology 2008;247(3):797–807.
22. Schilders E, Talbot JC, Robinson P, Dimitrakopoulou A, Gibbon WW, Bismil Q: Adductor-related groin pain in recreational athletes: Role of adductor enthesis, magnetic resonance imaging, and entheseal pubic cleft injections. J Bone Joint Surg Am 2009;91(10):2455–2460.
23. Dimitrakopoulou A, Schilders EM, Talbot JC, Bismil Q: Acute avulsion of the fibrocartilage origin of the adductor longus in professional soccer players: A report of two cases. Clin J Sport Med 2008;18(2):167–169.
24. Rizio L III, Salvo JP, Schürhoff MR, Uribe JW: Adductor longus rupture in professional football players: Acute repair with suture anchors. A report of two cases. Am J Sports Med 2004;32(1):243–245.
25. Schlegel TF, Bushnell BD, Godfrey J, Boublik M: Success of nonoperative management of adductor longus tendon ruptures in National Football League athletes. Am J Sports Med 2009;37(7):1394–1399.
26. Schilders E, Dimitrakopoulou A, Cooke M, Bismil Q, Cooke C: Effectiveness of a selective partial adductor release for chronic adductor-related groin pain in professional athletes. Am J Sports Med 2013;41(3):603–607.
27. O’Connell MJ, Powell T, McCaffrey NM, O’Connell D, Eustace SJ: Symphyseal cleft injection in the diagnosis and treatment of osteitis pubis in athletes. AJR Am J Roentgenol 2002;179(4):955–959.
28. Holt MA, Keene JS, Graf BK, Helwig DC: Treatment of osteitis pubis in athletes: Results of corticosteroid injections. Am J Sports Med 1995;23(5):601–606.
29. Verrall GM, Slavotinek JP, Fon GT, Barnes PG: Outcome of conservative management of athletic chronic groin injury diagnosed as pubic bone stress injury. Am J Sports Med 2007;35(3):467–474.
30. Mehin R, Meek R, O’Brien P, Blachut P: Surgery for osteitis pubis. Can J Surg 2006;49(3):170–176.
31. Williams PR, Thomas DP, Downes EM: Osteitis pubis and instability of the pubic symphysis: When nonoperative measures fail. Am J Sports Med 2000;28(3):350–355.
32. Hechtman KS, Zvijac JE, Popkin CA, Zych GA, Botto-van Bemden A: A minimally disruptive surgical technique for the treatment of osteitis pubis in athletes. Sports Health 2010;2(3):211–215.
33. Paajanen H, Hermunen H, Karonen J: Pubic magnetic resonance imaging findings in surgically and conservatively treated athletes with osteitis pubis compared with asymptomatic athletes during heavy training. Am J Sports Med 2008;36(1):117–121.
34. Radic R, Annear P: Use of pubic symphysis curettage for treatment-resistant osteitis pubis in athletes. Am J Sports Med 2008;36(1):122–128.
35. Hackney RG: The sports hernia: A cause of chronic groin pain. Br J Sports Med 1993;27(1):58–62.
36. LeBlanc KE, LeBlanc KA: Groin pain in athletes. Hernia 2003;7(2):68–71.
37. Brannigan AE, Kerin MJ, McEntee GP: Gilmore’s groin repair in athletes. J Orthop Sports Phys Ther 2000;30(6):329–332.
38. Brown RA, Mascia A, Kinnear DG, Lacroix V, Feldman L, Mulder DS: An 18-year review of sports groin injuries in the elite hockey player: Clinical presentation, new diagnostic imaging, treatment, and results. Clin J Sport Med 2008;18(3):221–226.
39. Muschaweck U, Berger L: Minimal repair technique of sportsmen’s groin: An innovative open-suture repair to treat chronic inguinal pain. Hernia 2010;14(1):27–33.
40. Meyers WC, McKechnie A, Philippon MJ, Horner MA, Zoga AC, Devon ON: Experience with “sports hernia” spanning two decades. Ann Surg 2008;248(4):656–665.
41. Jakoi A, O’Neill C, Damsgaard C, Fehring K, Tom J: Sports hernia in National Hockey League players: Does surgery affect performance? Am J Sports Med 2013;41(1):107–110.
42. Genitsaris M, Goulimaris I, Sikas N: Laparoscopic repair of groin pain in athletes. Am J Sports Med 2004;32(5):1238–1242.
43. Muschaweck U, Berger LM: Sportsmen’s groin-diagnostic approach and treatment with the minimal repair technique: A single-center uncontrolled clinical review. Sports Health 2010;2(3):216–221.
44. Kapron AL, Anderson AE, Aoki SK, et al: Radiographic prevalence of femoroacetabular impingement in collegiate football players: AAOS Exhibit Selection. J Bone Joint Surg Am 2011;93(19):e111–(1-10).
45. Silvis ML, Mosher TJ, Smetana BS, et al: High prevalence of pelvic and hip magnetic resonance imaging findings in asymptomatic collegiate and professional hockey players. Am J Sports Med 2011;39(4):715–721.
46. Gerhardt MB, Romero AA, Silvers HJ, Harris DJ, Watanabe D, Mandelbaum BR: The prevalence of radiographic hip abnormalities in elite soccer players. Am J Sports Med 2012;40(3):584–588.
47. Ganz R, Parvizi J, Beck M, Leunig M, Nötzli H, Siebenrock KA: Femoroacetabular impingement: A cause for osteoarthritis of the hip. Clin Orthop Relat Res 2003;(417):112–120.
48. Verrall GM, Slavotinek JP, Barnes PG, Esterman A, Oakeshott RD, Spriggins AJ: Hip joint range of motion restriction precedes athletic chronic groin injury. J Sci Med Sport 2007;10(6):463–466.
49. Larson CM, Pierce BR, Giveans MR: Treatment of athletes with symptomatic intra-articular hip pathology and athletic pubalgia/sports hernia: A case series. Arthroscopy 2011;27(6):768–775.
50. Hammoud S, Bedi A, Magennis E, Meyers WC, Kelly BT: High incidence of athletic pubalgia symptoms in professional athletes with symptomatic femoroacetabular impingement. Arthroscopy 2012;28(10):1388–1395.
51. Birmingham PM, Kelly BT, Jacobs R, McGrady L, Wang M: The effect of dynamic femoroacetabular impingement on pubic symphysis motion: A cadaveric study. Am J Sports Med 2012;40(5):1113–1118.
52. Economopoulos KJ, Milewski MD, Hanks JB, Hart JM, Diduch DR: Radiographic evidence of femoroacetabular impingement in athletes with athletic pubalgia. Sports Health 2014;6(2):171–177.
53. Larson CM, Sikka RS, Sardelli MC, et al: Increasing alpha angle is predictive of athletic-related “hip” and “groin” pain in collegiate National Football League prospects. Arthroscopy 2013;29(3):405–410.
Keywords:

athletic hip injuries; athletic pubalgia; sports hernia; osteitis pubis; adductor strain; femoroacetabular impingement; FAI; sports hip injuries; hip arthroscopy

© 2017 by American Academy of Orthopaedic Surgeons