Groin pain

Introduction

Groin injuries tax the diagnostic and therapeutic abilities of the clinician.^1,2 Although they are considered to be common and the most frequent overuse syndromes in some athletic activities such as soccer,³ they are difficult to manage correctly.

First, groin lesions involve a complex regional anatomy and often produce unusual presentations. Second, the lesions are often described using inaccurate terminology. For example, groin is a confusing term and groin injury usually describes multiple clinical conditions without clearly defining location or cause. It can, as is usually the case, mean a thigh muscle strain; it may refer to the genitalia; it can indicate hip disorders; or it may mean a problem in the lower abdominal wall. Finally, lesions in the back, in the sacroiliac region and within the abdomen may cause pain referred to the region of the groin.

History

The clinician confronted with the prospect of evaluating a patient who complains of groin pain should first of all ask the patient to point to the pain and also establish whether it is localized or diffuse. The groin area is not only the crossing site of trunk and lower extremity muscles but is also a region of considerable dermatomical overlap which includes T11, T12, L1, L2, L3 and S4 (Fig. 1). Pain in the groin can also be of extrasegmental origin.

Fig 1 The groin is a region of intense dermatomic overlap.

Once the localization and any radiation of the pain have been clarified, the examiner continues with the routine history which relates to problems in the back, sacroiliac region and the hip (see Ch. 36, 45, 61). Finally questions related to possible intra-abdominal disorders may be indicated. For example:

• Are fever, sweats or chills present (infection or neoplasm)?

• Has there been weight loss (neoplasm)?

• Are urinary symptoms such as dysuria, urgency, frequency or haematuria present?

• Are there bowel symptoms – diarrhoea, mucus or blood in the stool?

Clinical examination

The physical examination of the groin region should proceed through several steps to search for various disorders. A start is always made with a routine examination of the lumbar spine, always followed with a similar procedure on the thoracic spine. A thorough examination of the hip follows. If the signs and symptoms warrant, a complete accessory examination of the sacroiliac joints must also be performed.

Finally, and if appropriate, an abdominal examination may be added: palpation for pain, rebound and guarding, pulses, nodes, hernia and masses such as an abdominal aortic aneurysm.

Interpretation

The causes that can result in groin pain are numerous and are summarized in Table 1. Differential diagnosis is not difficult if the guidelines and principles for a good functional examination of the lumbar spine and hip are followed. However, occasionally the results may be confusing. This is usually caused by the fact that resisted movements in and around the groin not only stress the activated contractile structures, but often also induce transmitted stress on inert structures (bones, ligaments). For example, resisted ad- and abduction movements of the hip may indirectly put stress on the sacroiliac or iliolumbar ligaments or on the pubic symphysis.

Table 1

Lesions that can cause groin pain

Most lesions have been discussed in the chapters on the hip and the thoracic spine. However, there remain some common sport lesions that cause groin pain and deserve particular attention.

Femoral neck stress fracture

This overuse injury occurs primarily in endurance athletes (often in thin women who are frequently amenorrhoeic). Risk factors include training errors, inadequate footwear, running on poor surfaces and coxa vara (angular deformity of the hip).

The fracture causes groin pain, sometimes radiating down the anterior part of the thigh. The pain (often merely an ache) increases with walking or running and is relieved on cessation of activity. Pain at night may be present in long-standing instances.

Examination reveals an antalgic gait. There is usually a discrepancy between the obvious gait and the rather subtle signs on clinical examination: a full range of motion with pain produced at the extremes of hip rotation and on axial compression.^4,5

Early radiographs may be negative and absence of a fracture line does not rule out a stress fracture. A bone scan should be positive 2–8 days after symptoms appear. Further imaging studies such as computed tomography (CT) or magnetic resonance imaging (MRI) should be undertaken early if clinical suspicion warrants it.⁶

Treatment is based on the type of fracture. If the bone scan is positive but there is no visible fracture on plain film, initial treatment will consist of modified bed rest. This leads on to non-weight bearing with crutches and then pain-free weight bearing.³ If there is visible fracture on the plain film, open reduction and internal fixation is the treatment of choice because of the high risk of displacement. An already displaced fracture is considered an orthopaedic emergency and requires open reduction and internal fixation.

Athletes must be told that stress fractures of the femoral neck are serious injuries that can compromise an athletic career. Even in a successful recovery, return to participation in the chosen sport may take as long as 4–5 months.

Acetabular labral tears

Recent arthroscopic studies suggest that most internal derangement in the hip may be the result of impingement of acetabular labral tears.⁷ The history is that of internal derangement: a feeling of giving way or a sharp ‘twinge’ in the groin that radiates into the anterior thigh, especially with a rotation of the hip while rising from a seated position. On examination, a non-capsular pattern of limitation is found, with limitation of lateral rotation (see p. 642).

Some authors report successful diagnosis of impingement lesions with the so-called Thomas test.³ This involves flexion and external rotation of the hip and then allowing the extremity to abduct. The hip is then moved into extension, internal rotation and adduction. A positive test result is indicated by a palpable or audible click and the production of typical pain. Arthrography, MRI and arthroscopy can be used to confirm the diagnosis.

Treatment consists of manipulation (p. 642), although arthroscopic or open operative excision may be necessary in recalcitrant cases.