Anatomy, relevant to the present discussion, is depicted and described in Figures 24-1, 24-2, 24-3, and 24-4.

Definitions and Epidemiology

One study reported that 2.5% of all sports injuries were hip injuries, and in high school athletes, hip injuries were 5% to 9% of all athletic injuries. Apophyseal avulsions and musculotendinous strains are the most common acute injuries of hip, pelvis, and groin seen in youth sports.1–9

Mechanisms

Mechanisms are discussed below under specific injuries. Common mechanisms of injury include waterskiing and hurdling for hamstrings tears or avulsions, direct trauma to the anterior pelvis for iliac crest avulsions, and skiing and snowboarding falls with associated hip dislocations, and acetabular fractures.

Clinical Presentation

The athlete may present with a history of direct or indirect injury to the hip and pelvis from a fall, collision, or injury from “noncontact” sports. The young athlete may also present with chronic hip pain after overuse, such as distance running, which may be associated with a stress fracture of the femoral neck, or other associated injuries.4,5

The main symptom in many cases is the sudden onset of groin or hip pain, or pain along the iliac crest with avulsion injuries, as well as thigh or buttock pain with hamstring tears or apophyseal injuries. The patient may be reluctant to bear weight on the limb with a proximal femur or acetabular fracture, or an injury to the femoral head. The young athlete may present complaining of a click or catch with snapping in their hip resulting from an injury to the labrum or to the iliopsoas tendon or bursa6,7

Physical Examination

Examination should include lower back and both lower extremities.

Inspection

Look for swelling about the hip and surrounding structures, and any bruising or evidence of direct trauma to the soft tissues, such as ecchymosis about the proximal posterior thigh with a hamstring strain. Observe gait.

Range of Motion

Assess active and passive range of motion (ROM) of the hip: flexion, extension, abduction, adduction, and internal and external rotation (Table 24-1). Note any limitation, pain, clicking, or snapping. Compare the injured and uninjured hips in every patient.7–9

Strength testing should be done on all muscle groups bilaterally. The examiner needs to check strength in flexion, extension, abduction and adduction, as well as rotation of the hips. Often subtle hip stabilizer weakness and lumbar and abdominal muscle weakness will contribute to poor body mechanics, thus leading to easy fatigability, pain, and increased susceptibility to injury in the young athlete.

Many high-level athletes do not have good core stability and strength, and this can be further assessed by having the athlete stand on one leg while flexing the hip and knee of the other leg. If the athlete loses balance or corkscrews on bending rather than flexing and extending with his trunk balanced and perpendicular to the ground, there is significant core weakness present (Figure 24-5). A simple Trendelenburg test (Figure 24-6), which demonstrates tilting of the pelvis away from the affected hip in single-leg stance, will also aid in uncovering subtle core weakness. Core weakness is related to trunk and lower back muscle strength as well as hip abductor, adductor, flexor, and extensor strength; it is a frequent correlate of hip pain, lower extremity muscle weakness, and diminished athletic performance in sports ranging from rowing, to hockey, basketball, soccer, baseball, handball, tennis, and others.10

Palpation

This should include gently stressing the pelvis in AP and lateral compression (Figure 24-7), and palpation over the symphysis pubis, greater trochanter, and ischial tuberosity. Palpation of the femoral, posterior tibial and dorsalis pedis pulses, capillary refill, and pin-prick sensation in both lower extremities should be included. Note the skin for trophic changes or abrasions.

Special Tests

Trendelenburg and single-leg stance tests are described above.

To test for posterior acetabular labral tears the patient is placed supine, the hip supported and flexed in abduction and external rotation with the knee flexed (Figure 24-8). The hip is then extended, adducted, and internally rotated. There is often a clunk or click with the presence of a labral tear, and patients commonly report that this examination reproduces their symptoms. With external snapping hip or iliopsoas injury, the hip is flexed and adducted in internal rotation then extended, abducted, and externally rotated (Figure 24-9). This often produces a click, or snapping over the anterior proximal thigh, and very often reproduces the patient’s pain.

For a tight iliotibial band the patient is placed on the unaffected side facing away from the examiner at the edge of the table, and the hip is extended and the affected leg lowered below the table’s edge to perform an Ober test (Figure 24-10). This will often reproduce the athlete’s discomfort, and also will demonstrate limited flexibility in those with a tight iliotibial band.

The athlete should also be assessed for tightness in the quadriceps (Figure 24-11). Hamstrings flexibility is assessed with the hip at 90 degrees, while extending the knee with the calf supported.

One should also check for Achilles tendon tightness, with the knee bent at 90 degrees and the patient sitting up by measuring dorsiflexion of the ankle.6–8,11,12 Measure the leg length (Figure 24-12).

Diagnostic Imaging

Injuries to the apophyses may be best seen on plain films. Other imaging studies such as CT scan or MRI scan may be needed if it is difficult to visualize the injury on plain films. Bone scan is useful for stress fractures and other injuries about the pelvis, but will not be positive for approximately 3 days after an acute injury, and may not show the level of detail needed for some injuries. MRI is usually positive within 24 hours of injury because of the bone edema associated with an acute injury. MRI is also useful to demonstrate associated muscle, tendon, chondral, and labral injuries.

In a suspected labral tear of the hip, an MR arthrogram is indicated. Ultrasound may helpful in some cases to demonstrate soft tissue or tendon injuries, bursal fluid, and hip effusions, but requires a technically adept operator who performs these tests frequently to obtain the best results. CT imaging is useful to look at suspected femoral head fractures, acetabular fractures, and also to delineate occult fractures about the hip. In many level I trauma centers, a patient presenting with significant pelvic or abdominal trauma will undergo CT scanning in the emergency department by the trauma service prior to the patient being seen by or referred to other physicians. Current high-definition, high-speed spiral CT scan has supplanted plain film Judet views for acetabular fractures in many centers. There are no specific indications at this time for the performance of PET scans on acute musculoskeletal injuries in young athletes.13–15

Treatment

In the acutely injured hip, the first priority is to assess the patient’s vascular as well as neurologic status, and quickly ascertain whether the hip joint itself is injured or dislocated. In a patient with marked discomfort in the groin and hip, who is reluctant to move the hip, the best course of action is to obtain plain films of the affected hip and pelvis immediately and then treat based on the findings of these films and other imaging studies, which may then be needed to further delineate the injury and plan treatment. Treatment for specific injuries is described in following sections.

Definition and Epidemiology

Overall, most athletic hip dislocations are posterior. Hip dislocations occur in freestyle skiing and snowboarding, as well as in motocross and other high-energy and impact sports. In addition to hip dislocation, athletes in high-impact or jumping sports may also sustain chondral injuries and fractures of the femoral head, which can predispose the patient to significant long-term disability, early arthritis, loss of ROM of the hip, and chronic hip pain. Hip dislocation with a femoral head or pipkin fracture was present in 30% of snowboarders with a hip dislocation and 12.5% of skiers with a hip dislocation2,16

Mechanism

Most hip dislocations are posterior and commonly occur from an anterior blow to a flexed knee, and may be associated with a fracture of the posterior wall of the acetabulum. Anterior dislocations are less common.16

Clinical Presentation

Patients commonly present with a history of a fall or other significant trauma, and are unable to move the hip or bear weight. Following acute traumatic event, an athlete presents with a history of acute, severe hip pain, decreased range of motion, and does not want to move the leg or bear weight. The mechanism of injury may help determine whether the dislocation is anterior or posterior. The posteriorly dislocated hip is held in flexion, adduction, and internal rotation, and the patient will complain of marked pain in the hip. The athelete will not be able to range the hip, or bear weight. The anteriorly dislocated hip is held in flexion, abduction, and external rotation.16

Diagnostic Imaging

Standard x-rays will show the dislocated hip. CT scan or MRI scan may be indicated to assess associated fractures or labral injuries.

Treatment

A hip dislocation is an emergency and must be seen and reduced within a few hours of injury. On field reduction can be attempted but is neither uniformly practiced nor recommended. Initial treatment following reduction is non-weight bearing for 6 weeks, often followed by repeat MRI scan. Some patients will develop chondrolysis or avascular necrosis of the femoral head following a dislocation, particularly a posterior dislocation. Return to sports can be allowed in 6 to 12 weeks if imaging, including MRI, is negative and there is no pain with ROM of the hip or with ambulation.