Although groin pain was reported as an important athletic injury at least as early as 1980 by Renström and Peterson,¹ it remains a major challenge in contemporary sports medicine. In a prospective 2-year study of injuries among 17 male football teams,² groin injuries comprised 5% of all injuries. Ekstrand and Gillquist³ found in a study of 12 football teams over a 1-year period that 13% of all injuries were localised in the groin. The injury incidence rate was 18 groin injuries per 100 football players per year. Engström et al⁴ reported 12% groin injuries and a groin injury incidence rate of 16% in a 1-year study of 64 elite football players. Among elite female football players, Engström et al⁵ observed a groin injury incidence rate of 12%. Groin injuries are also known from other sports such as ice hockey, running, tennis, rugby, American football, basketball and others.^{6,7,8,9,10,11,12,13,14,15,16,17,18,19} No comparative prospective studies are published considering matched populations and the rate of exposure between different sports. Renström and Petterson¹ described differential diagnoses among 55 athletes from different sports with groin pain. Adductor longus pain comprised 62%, rectus abdominis pain 22% and other locations 16%. Lovell,²⁰ in a retrospective review of 189 cases of groin pain in athletes, finds more than one diagnosis accounting for the groin pain in 27% of the patients.

A major limitation in the field of groin pain research is that there is no agreement about a scientific taxonomy. Thus, the literature provides no consensus on diagnostic criteria for the various causes of groin pain among athletes. In fact, the cause of chronic groin pain remains very much in debate and most studies are not based on systematic clinical assessments using reliable examination methods, and well-defined diagnostic entities are not reported.

Therefore, this prospective study aimed to describe the range of clinical syndromes detected when a reliable, standardised physical examination method was used to assess sports-related groin pain among 207 consecutive patients. Although clearly limited by being descriptive in nature, such a study could provide an important perspective as to the structures that warrant thorough physical examination, particularly if more than one structure is commonly found to be abnormal.

MATERIALS AND METHODS

Two hundred and seven athletes with complaints of pain located in the groin during and/or after sports activities and lasting for >2 months were referred to the author from colleagues and physiotherapists. Age, gender and sport activities were recorded.

A thorough and systematic medical history was used to seek the presence of systemic symptoms, joint symptoms, urinary symptoms, gynaecological symptoms or back pain. Data were also recorded regarding the location of pain, how the pain began, whether pain was related to certain activities (ie, certain movements in the sporting activity) or to coughing, sneezing, lifting and so on, and whether pain was present in the night and/or in the morning.

A standardised clinical protocol was used to examine all patients; tables 1 and 2 show the details of this protocol. The interobserver and intraobserver reliability of the clinical examination techniques for the adductor, iliopsoas and rectus abdominis muscles, as well as for the symphysis joint, were good in all cases.⁴² The author performed all examinations. The protocol was designed to detect one or more pathoanatomical structures associated with symptoms and to exclude urological/gynaecological and other aetiologies. In each case, the clinical findings were compared with the non-symptomatic side. Supplementary radiographic, ultrasonographic and bone scintigraphic examinations were only used when clinically indicated (eg, a clinical suspicion of fracture, stress fracture, hip arthrosis, instability in the symphysis joint, bursitis, cancer or snapping psoas).

When more than one clinical entity was established, the author attempted to evaluate the entity that appear to be clinically responsible for the greatest component of the groin pain (1st clinical entity), and then rank conditions in a descending order of clinical importance (2nd, 3rd entity). This approach was also found to be useful by Lovell.²⁰

RESULTS

Demographic variables

There were 11 women and 196 men with sports-related groin pain. The women ranged in age from 16 to 48 years, with a median age of 26 years, and the men ranged in age from 16 to 50 years, with a median age of 28 years.

Football was by far the most common sport among men, whereas running was the most common among women. Football accounted for 135 (69%) and running accounted for 30 (15%) of the men with groin pain. The women athletes included two football players, two long-distance runners, three recreational runners, one orienteering runner, one hurdle-runner, one weight lifter and one volleyball player.

Table 3 shows the distribution of the 207 patients in the different sports in relation to the two major primary clinical entities.

Primary clinical entity

Table 4 shows the distribution of the 13 different clinical entities detected. Adductor-related pain was considered the primary clinical entity in 119 (58%) patients (all men). Iliopsoas-related pain was the primary clinical entity in 73 (35%) patients. Other primary clinical entities were relatively rare. Among women, iliopsoas-related pain was the primary clinical entity in nine cases, one woman had a snapping psoas and one had a stress fracture of the inferior pubic bone. Although prevalent among men, adductor-related pain was uncommon among female athletes (one case, secondary to iliopsoas-related pain).

Secondary and tertiary clinical entity

A secondary and, at times tertiary, clinical entity was found in 69 (33%) patients. Iliopsoas-related pain was the most frequent of these additional clinicial entities, but pain related to the rectus abdominis muscle was also found. In all, 16 (8%) patients had a tertiary clinical entity. Table 4 shows the distribution of secondary and tertiary entities. A total of 48 patients had iliopsoas-related pain as secondary or tertiary clinical entity, 46 of these had the adductors as the primary origin of pain. This systematic approach never revealed more than three clinical entities in any patient explaining the groin pain.

Among football players, specifically, adductor-related pain was the most common primary entity (69%), and iliopsoas-related pain was the major secondary clinical entity (60%; table 5). In this population, iliopsoas-related pain was the primary origin of pain in 26%. Pain related to the rectus abdominis was found in 20 patients, 15 of whom were football players. In 18 patients, the rectus abdominis-related pain was considered to be a secondary clinical entity, and in 17 patients, it was secondary to adductor-related pain. In all, 37 runners were examined (long distance, middle distance, recreational, orienteering, hurdles and sprint), and among these, iliopsoas was the most prevalent clinical entity accounting for two-thirds. In all, seven of the 11 female patients examined in this study were runners and six of these had iliopsoas as their primary origin of pain.

DISCUSSION

This prospective assessment of 207 consecutive athletes with groin pain used a reliable method of physical examination,⁴² which extends previous comparable clinical studies in number and in method. An innovation in this study is the approach to determine “clinical entities” rather than to make a diagnosis of the tissue. This approach has been used successfully in other clinical settings where it is difficult to ascertain the pathology clinicially (eg, lumbar back pain).

Adductor-related pain was the most prevalent finding; importantly, over 40% of the patients in this study had more than one abnormal clinical entity. Thus, iliopsoas-related pain, pain in the lower abdomen radiating into the groin and other multiple clinical entities also seemed to contribute to the symptoms, even though they were most often not considered the primary clinical entity.

Adductor-related pain and osteitis pubis

The author eschews the use of the term “osteitis pubis”; that term should be reserved for describing a diagnosis of a complication due to surgery in the retropubic and parapubic regions.^43–49 In multiple studies, mainly case reports, osteitis pubis has been used as the diagnostic term for groin pain in athletes^15,50–54 when the radiological findings are similar to those found in the original osteitis pubis. In many of the studies describing osteitis pubis as a diagnosis of groin pain in athletes, adductor-related symptoms are at least present, and often dominant.^{20,50,51,55–58}

The current literature is not in agreement with the definition relating to the term “osteitis pubis”. Lloyd-Smith et al⁵⁷ retrospectively assessed 204 patients with hip and pelvic injuries, and suggest that osteitis pubis is a diagnosis that should be considered with adductor-strain pain that is severe or atypical. Fricker et al⁵⁸ retrospectively assessed 59 patients diagnosed as osteitis pubis, the majority being classified as sport related. The most-frequent symptoms and signs used to describe these patients were tenderness at the symphysis pubis and adductor pain, either as tenderness at the origin or as pain when tested for adductor strength. Harris et al,⁵⁵ in a radiological study of the pubic symphysis mainly in football players, reported radiological abnormalities claimed to be “diagnostic” of traumatic osteitis pubis. The symptoms were pain produced by stretching of the adductors, tenderness over the symphysis pubis and at the ischiopubis ramus (the insertion of the adductor longus and gracilis). Lovell et al⁵⁹ reported a high prevalence of bone marrow oedema at the pubic symphysis with MRI in a group of asymptomatic football players. There was no clear relation between the amount of oedema and groin symptoms. McCarthy and Dorfman⁵⁶ describe osteitis pubis as “a broader diagnostic category that encompasses several different aetiological entities in or near the symphysis”. These positions suggest that athletes with “groin pain related to the adductors” and athletes diagnosed as having osteitis pubis may, at least in part, be having diagnostically overlapping entities. Robinson et al⁶⁰ have shown that the symptoms and abnormalities in the pubic bone on MRI correlates significantly and reproducibly with the symptomatic adductor enthesis. Therefore, this author contends that the term “osteitis pubis” should be reserved to describe a radiological sign rather than a diagnostic entity in this group of patients.

Iliopsoas-related pain

Iliopsoas-related pain was the primary clinical entity found in one-third of the patients and the secondary and tertiary clinical entity in 55% of patients; it was the major problem among the group of runners. This prevalence is consistent with that reported among runners,⁵⁷ in which iliopsoas injury proved to be the most common soft-tissue injury cause of groin pain. A major hip flexor, the iliopsoas is a very important muscle in the process of running and, as such, at risk of being overused.^9,18,61,62 The high incidence of adductor-related and iliopsoas-related pains in the same patients could indicate a high degree of dependence between these two muscles in relation to pelvic stability.^18,63,64 Iliopsoas-related pain can mimic other conditions such as gynaecological disorders, appendicitis or hernia.^62,65

Hernia and lower abdominal pain

Hernias in the classic sense and sports hernia were seen in one and four patients, respectively. The sports hernia or sportsman’s groin or sportsman’s hernia^26,66,67 has been described as a common diagnosis in otherwise-unexplained groin pain. The signs are tenderness above the inguinal ligament, lateral and superior to the pubic tubercle and/or lower abdominal pain radiating into the upper medial aspect of the thigh. The operative findings are a deficient posterior inguinal wall²⁶, in some cases with a split conjoint tendon.^27,67,68 A number of patients diagnosed with iliopsoas injury in the present study complained of lower lateral abdominal pain and palpatory pain of the psoas in the lower abdomen. In all, 20 patients had rectus abdominis pain with contraction against resistance and tenderness at the distal insertion of the rectus abdominis. The similarity of the symptoms found in patients with iliopsoas pain, rectus abdominis pain and sports hernia calls for an evaluation of the diagnostic methods used in these cases.

Multiple clinical entities

Multiple origins of the groin pain were found in several patients, 34% had two clinical entities and 8% had three clinical entities. Whether this extent of pathology reflects chronicity of cases or the referral bias to the author cannot be known. Nevertheless, it is consistent with Ekberg et al³⁷ who speculated that long-standing groin pain in athletes can be the result of more than one disease, and needs a multidisciplinary approach. The diagnoses of prostatitis or hernia were found in 50% of their patients. In this study, there were no patients with prostatitis and few (5) patients with hernia or sports hernia. Most of the diagnoses were instead associated with the pelvis and with the muscles and ligaments connected to the pelvis.

The pelvis contributes greatly within sports biomechanics^63,69–71 as most movements depend to some degree on a well-balanced pelvis that requires the complex orchestration of different muscle groups, ligaments and joints. It is tempting to speculate that if one of these structures is injured and not functioning optimally, the balance around the pelvis will be disturbed and place other pelvis-related structures at risk.^{55,64,72–75} This might explain why more than one origin of pain was found in more than one-third of the patients. But the study design does not allow for any conclusions to be drawn. In some patients, a secondary clinical entity was found that might be a precipitating factor for the entity considered to be the primary. This could be the case in the two patients with hip arthrosis, perhaps leading to the development of a pain of thoracolumbar origin and iliopsoas-related pain, respectively.

Limitations of the study have been outlined and include the fact that there is no “gold standard” against which the diagnostic entities can be validated. Also, the referral pattern to the author may not reflect the one in Denmark or in other parts of Europe and the world. Thus, the sample is at risk of ascertainment bias. Future studies will reveal the degree of homogeneity in the diagnostic entities among patients with chronic groin pain in various nations worldwide. Also, it is acknowledged that the ranking of primary, secondary and tertiary clinical entities has not been formally tested. For this reason, the main conclusions are independent of this ranking.

In summary, this clinical study extends previous work because of its size, prospective nature and validated examination protocol. It provides the first attempt to move the clinical evaluation of long-standing groin pain from a “diagnostic label” paradigm to one where “diagnostic entities” are considered. This may, more accurately, reflect diagnostic limits, but further studies using a gold standard are needed to address that question fully. A major clinical implication of this study is the fact that multiple entities are present in well over one third of patients. This behoves clinicians to thoroughly examine the iliopsoas and other regions, even when one cause has been found for a patient’s long-standing groin pain. The author also argues against the continued use of the term “osteitis pubis”. Along with terms like “shin splints”, this term may be permanently poisoned because of the range of meanings attributed to it. In the future taxonomy, there may not be room for the term “osteitis pubis” per se. Future research that adopts a similar “clinical entity” approach to patients, and also systematically images them (eg, MRI and ultrasonography) would be very useful.