Athletic Pubalgia/Core Muscle Injury and Adductor Pathology

Anatomy

Given the complexity of the anatomy of the hip joint, pelvis, pubic symphysis, and the associated abdominal wall, a thorough understanding of relevant anatomy is important for the clinician assessing an athlete with groin pain. This is particularly true for the anatomic considerations of athletic pubalgia. The pubic symphysis is perhaps the simplest structure relevant to athletic pubalgia and is a nonsynovial amphiarthrodial joint. Static stability of the joint is provided by the disk and four ligaments. The arcuate or inferior ligament has attachments to the inferior articular disk, the inferior attachment of the rectus abdominis, and the adductor and gracilis aponeurosis. The superior ligament spans the space between the pubic tubercles. The anterior ligament blends with fibers of the external oblique and rectus abdominis superficially. The deep portion of the anterior ligament attaches to the intra-articular disk. The posterior ligament is poorly developed. The term pubic joint was introduced by Myers and has been used to describe the complex biomechanics of the muscular envelope at the pubis symphysis. The pubic symphysis acts as the fulcrum for forces generated at the anterior pelvis. It represents the common attachment of the confluence of the rectus abdominis fascial sheath with the fascial sheath of the adductor longus; these merge anterior to the pubis to form a common sheath. Pathology of other adductors, including the adductor brevis and pectineus, is less commonly seen in athletic pubalgia. Imbalance between the rectus abdominis and adductor muscular and pathology of the common attachment appears to be a major factor in athletic pubalgia.

The abdominal wall has a layered structure. From superficial to deep, the structures of the abdominal wall are skin, fascia, external oblique muscle/fascia, internal oblique muscle/fascia, transversus abdominis muscle/fascia, and transversalis fascia. The posterior fascia is deficient in the lower third of the rectus. Fibers from the rectus, conjoint tendon (fusion of the internal oblique and transversus abdominis fascia), and external oblique merge to form the pubic aponeurosis (also called rectus abdominis/adductor aponeurosis), which is confluent with the adductor and gracilis origin. The conjoint tendon inserts anterior to the rectus abdominis on the pubis ( Fig. 84.1 ).

Weakness of the floor of the posterior inguinal canal may play a role in athletic pubalgia. The inguinal canal is formed anteriorly by the external oblique aponeurosis; posteriorly by the transversalis fascia and conjoint tendon; superiorly by the transversalis fascia, internal oblique, and transversus abdominus; and inferiorly by the inguinal ligament (from the external oblique aponeurosis). The inguinal canal contains the spermatic cord (in males), round ligament (in females), genital branch of the genitofemoral nerve (which supplies motor function to cremaster muscle and sensory function to the scrotum), and ilioinguinal nerve (supplying sensory function to the groin). The role of nerve-mediated pain in athletes with groin pain remains somewhat poorly understood and controversial. Knowledge of the nerve anatomy of the groin is important in elucidating the potential role of each nerve in athletic pubalgia. One possible source of pain has been theorized to be the result of entrapment of the genital branch of the genitofemoral or ilioinguinal nerve. Weakness of the posterior inguinal floor has been proposed to result in dynamic compression of the genital branch of genitofemoral nerve. The symphysis itself is innervated by branches of the pudendal and genitofemoral nerves.

Historical Background

Groin injuries were discussed in the medical literature as early as 1932, when Spinelli reported on pubic pain in fencers. Nearly 50 years later, in 1980, Gilmore recognized a “severe musculotendinous injury of the groin” in three professional soccer players. He identified a triad of pathology including injuries to the external oblique aponeurosis and conjoint tendon, avulsion of the conjoint tendon from the pubic tubercle, and dehiscence of the conjoint tendon from the inguinal ligament. He later reported a 97% return to sport after surgical repair.

In 1993, Hackney first used the term sports hernia to describe a syndrome of groin pain in athletes that had failed nonsurgical management. At surgery, he identified weakening of the transversalis fascia with separation of that fascia from the conjoint tendon, dilation of the inguinal ring, and one case of a small direct hernia. He treated all patients with a surgical repair of the posterior inguinal wall and obtained an 87% return to sport in 15 athletes. Irshad et al. described “hockey groin syndrome” in 22 National Hockey League players in 2001. They found tearing of the external oblique aponeurosis and entrapment of the ilioinguinal nerve. Meyers proposed that use of the term athletic pubalgia would be more appropriate for the constellation of injuries to the abdominal wall, adductors, and pubic symphysis presenting with pubic area or inguinal pain than the more commonly used sports hernia . He proposed that the primary pathology in athletic pubalgia was an imbalance between the strong adductors and the relatively weak abdominal muscles. More recently, the term core muscle injury has also been increasingly used to describe athletic pubalgia. Meyers describes 17 different variants of athletic pubalgia, the most common of which were multiple tears or detachment of the anterior and anterolateral fibers of the rectus abdominis from the pubis and combined injuries to the rectus and adductors.

Over the last two decades, treatment of athletic pubalgia has become increasingly common in high-level athletes involved in cutting/pivoting and acceleration/deceleration sports, including soccer, football, and ice hockey. Between 2012 and 2015, some 4.2% of athletes of the National Football League (NFL) had undergone surgical treatment of athletic pubalgia (most commonly defensive backs and wide receivers).

As the understanding of intra-articular hip pathology has improved, there has been increasing recognition that acetabular labral pathology and femoroacetabular impingement can coexist with athletic pubalgia. Significant overlap between athletes with athletic pubalgia and femoroacetabular impingement is seen in clinical practice but has only recently been recognized. Feeley et al. described the “sports hip triad” of labral tears, rectus abdominis strain, and adductor strain. The loss of internal rotation of the hip appears to play a role in the development of groin pain and osteitis pubis. Based on these observations, Birmingham et al. performed a cadaveric study looking at the effect of femoroacetabular impingement on rotation at the pubic symphysis in a cadaveric model. At higher torque values, motion through the symphysis was much greater in cadavers with simulated cam morphology than in the native hip state. This supports the previous hypothesis that the altered rotational profile seen in the setting of femoroacetabular impingement contributes to altered mechanics at the pubic symphysis through stress transfer. Limitations in range of motion (ROM) at one location can result in additional motion occurring at other locations.

Larson et al. reported the outcomes of surgical treatment in a subset of athletes with coexistent femoroacetabular impingement and athletic pubalgia. Failure to treat both pathologies resulted in a low return to sport (25% if athletic pubalgia was addressed in isolation, and 50% if the intra-articular hip pathology was addressed in isolation). This prompted the development of a surgical protocol to address both etiologies under the same anesthesia when athletes present with both symptomatic athletic pubalgia and intra-articular hip disorders (FAI). Using this approach, these investigators achieved an 85% to 93% return to sport.

In addressing the athlete with groin pain, it is therefore important to carefully investigate other potential sources of the athlete's pain. Intra-articular hip pathology and associated hip pathomorphology must be carefully screened for if symptomatic and limiting. This assessment should also take into account the high rates of potential asymptomatic labral pathology on magnetic resonance imaging (MRI) in this population. Additionally, it is important to be aware of the broader differential diagnosis of groin pain. Disorders of the gastrointestinal, genitourinary, or gynecologic systems must also be considered, with several authors identifying tumors, Crohn disease, and other pathologies in the evaluation of the athlete with groin pain.

History

Athletic pubalgia is particularly common among those who participate in sports requiring repetitive twisting, pivoting, and cutting motions, as well as activity requiring frequent acceleration and deceleration. Trunk hyperextension and hip hyperabduction place significant stress across the pelvis, including the rectus abdominis and adductors. Soccer, football, ice hockey, and rugby have a particularly high incidence, with a lower incidence reported in basketball and baseball. Meyers noted that in the 1980s, less than 1% of his patients with athletic pubalgia were female. Over the last two decades, however, that has changed dramatically, and female patients now represent 15% of patients presenting with athletic pubalgia.

Athletes with athletic pubalgia may report an insidious onset of groin pain or less commonly have a more acute presentation. Most athletes report pain with athletic activities but not at rest. Although there is some variability in the location and characteristic of symptoms, Meyers et al. found that all of their athletes reported lower abdominal pain with exertion, whereas 92% had minimal to no pain at rest. Forty-three percent developed bilateral symptoms and 67% developed adductor pain after the onset of lower abdominal pain. Pain may also radiate to the rectus, perineum, or testicular region. Exacerbation typically occurs during activities involving kicking, acceleration, and pivoting. Abdominal crunches or situps, coughing, or sneezing may also reproduce symptoms. Osteitis pubis presents in a similar fashion, with pubic pain that may radiate to the adductors and is typically exacerbated by weight bearing. Intra-articular hip pathology from labral tears or femoroacetabular impingement typically presents with deep anterior groin pain that may radiate to the anterior thigh and lateral hip. There is considerable overlap between intra-articular hip symptoms and athletic pubalgia symptoms, which, when combined with high rates of potentially asymptomatic pathology of radiographs and MRI, increases the complexity of making an accurate diagnosis in this challenging patient population.

Physical Examination

Assessment for athletic pubalgia should begin with palpation of the pubic symphysis, insertion of the rectus abdominis, adductor origin, external and internal obliques, transverses abdominis, pectineus, gracilis and inguinal ring for areas of tenderness. Provocative testing can be useful to reproduce symptoms, including simulated coughing, Valsalva maneuver, resisted situps (46%), ( Fig. 84.2 ), or resisted hip adduction. With traditional assessment for inguinal hernia, there is no palpable hernia, but this should be ruled out. There is usually tenderness around the conjoint tendon, pubic tubercle (22%), adductor longus (36%), superficial inguinal ring, or posterior inguinal canal. Detailed assessment of hip ROM including provocative testing is warranted given the interplay between athletic pubalgia and FAI.

Exam findings for osteitis pubis frequently overlap (or coexist) with athletic pubalgia and include tenderness of the pubic symphysis (67%), adductor origin tenderness (59%), pain with the adductor squeeze test (96%), and apprehension throughout the hip's ROM. More severe cases of osteitis pubis may present with a classic waddling gait pattern.

Imaging

Radiographic Analysis

Plain radiographs are vital in the initial evaluation of the athlete with hip or groin pain. A number of pathologies including osteitis pubis, avulsion fractures, stress fractures, apophysitis, osteoarthritis, femoroacetabular impingement, and hip dysplasia may be identified on radiographs. It is essential to obtain good-quality, properly oriented images according to an established imaging protocol.

The anteroposterior (AP) pelvic view ( Fig. 84.3 ) may be used to evaluate the pubic symphysis for evidence of osteitis pubis, including sclerosis, fragmentation, and cyst formation within the pubic ramus as well as symphyseal widening. Most authors now favor performing this radiograph in the standing position to best simulate the functional position of the pelvis, which commonly differs from the supine position. In evaluating for femoroacetabular impingement, also assed are deformities of the femoral head neck and acetabular depth and version. In the adolescent athlete, the AP view can be useful to identify apophyseal avulsion injuries. Additionally, stress fractures of the femoral neck and pubic rami and sacroiliitis may be identified.

In cases of possible pubic symphyseal instability associated with osteitis pubis, stress radiographs may be useful. The stability of the pubic symphysis can be determined on single-leg-stance AP views (the “flamingo view”). Symphyseal widening greater than 7 mm or vertical translation greater than 2 mm on a single-leg-stance view suggests instability of the pubic symphysis.

Magnetic Resonance Imaging

MR arthrography has been used for the assessment of intra-articular hip pathology. More recently, noncontrast 3.0 Tesla MR has been evaluated and found to be sensitive for intra-articular pathology including articular cartilage injury and labral pathology. The use of arthrography on MR is now dependent on the surgeon and institutional preference. Routine assessment of common sites of pathology in athletic pubalgia on hip MRI can be useful in athletes with groin pain, but dedicated protocols for pelvic MRI are optimal for visualization. Coronal oblique and axial oblique sequences through the rectus insertion and pubic symphysis should be obtained in addition to standard sagittal, coronal, and axial sequences. MRI is 68% sensitive and 100% specific for rectus abdominis pathology as compared with findings at surgery (the gold standard) and is 86% sensitive and 89% specific for adductor pathology. MRI is 100% sensitive for osteitis pubis. Nonarthrographic studies may be preferred for in-season athletes to avoid the potential for irritation secondary to the administration of intra-articular contrast.

The MRI should be evaluated in a systematic fashion for pathology consistent with athletic pubalgia. The pubic bones should be evaluated for edema, subchondral sclerosis, and cysts suggestive of osteitis pubis ( Fig. 84.4 ). Evaluation of the tendinous insertions of the core muscles around the pubic symphysis should then be performed ( Fig. 84.5 ). Frequent findings include fluid signal within the rectus abdominis or adductor origin, thickening of either structure, peritendinous fluid, or partial or complete disruption of either tendon. Most commonly there is a confluent fluid signal extending from the anteroinferior insertion of the rectus abdominis into the adductor origin, with corresponding fluid signal in the pubis.

Decision-Making Principles

Treatment decisions must take into account a number of factors including the degree of limitation and ability to participate in the athlete's respective sport, duration of symptoms, pathology identified on physical examination and imaging, response to prior treatment modalities, and where the athlete is with respect to his or her training, sport season, and upcoming athletic events. The common locations of pain are the groin (FAI, athletic pubalgia, adductor), lower abdomen or pubic symphysis (athletic pubalgia, adductor longus), posterior hip (FAI, proximal hamstring, low back, sacroiliac joint, sciatic nerve entrapment disorders), or lateral thigh/hip (iliotibial band or gluteus medius/minimus). Conservative management should be attempted prior to surgical intervention. If no previous treatment has been attempted at presentation, a conservative trial should include rest, nonsteroidal antiinflammatory drugs (NSAIDs), physical therapy, and injections in select situations. Physical therapy is focused on restoring core muscle strength and correcting any underlying imbalance between core muscle groups. If the athlete continues to be symptomatic after 6 to 12 weeks of nonsurgical treatment, then surgery may be considered. The timing of the surgery depends on the degree of disability and the time point in the season. If the athlete must participate and he or she is productive and functional, a delay until after the season may be attempted. Surgery can then be performed at the end of the season if the athlete remains symptomatic. If the athlete is not able to compete at a reasonable level, then in-season or season-ending surgery can be considered. If there is a combined pathology such as FAI and athletic pubalgia, these can be surgically addressed at the same setting or staged in order to minimize postoperative rehabilitation time, total time lost from participation, and potential need for subsequent surgery. There is, however, no evidence to show that carrying out these procedures separately or in a staged manner, has any negative impact on outcome.

Treatment Options