diagnosis

determining the cause of hip pain

Determining the cause of hip problems can be challenging. Bilateral disease is not uncommon and spinal or knee problems need to be ruled out as masking hip pain. Flexion or rotation symptoms (those that worsen with increased activity, and pinching or clicking) can be used to assess the potential causes of hip pain.

Hip problems can be divided into intra-articular and extra-articular injuries and it is important to differentiate between the two.

• Extra-articular hip problems are usually the result of activity leading to inflammation, tendonitis and bursitis of the soft tissue.
• Symptoms of intra-articular hip problems include clicking, catching, locking, giving way or restricted range of motion. These problems are usually preceded by a dramatic event, are generally not tender on palpitation, and are exacerbated with activity and improved with rest.

intra-articular hip problems

Patients presenting with intra-articular hip pain can often relate their hip pain to an acute twisting or falling episode. Playing sports that involve repetitive hyperextension and external rotation appear to increase the risk of developing intra-articular hip problems. Pain is generally worse when twisting and going up or down stairs or inclines. Patients may also complain of painful ''catching' in the hip, particularly when standing up1.

An intra-articular injury is often characterised by pain in the groin, front thigh and the middle of the knee, in addition to mechanical symptoms such as catching, locking and giving way. To confirm, ask where a patient feels pain and look for the 'C' sign where the patient places their index finger over the front of the hip and thumb the other side of the pelvis1.

Physical examination should start by watching a patient stand and walk. Patients with intra-articular pathology may stand with the hip flexed and walk with a shorter stride.

A patient's range of motion should also be examined via a side-to-side evaluation of internal and external hip rotation, hip abduction, adduction and flexion. These tests are designed to recreate pain and mechanical symptoms. Some commonly used tests include:

1. Log rolling of the hip when the patient is lying on their back, face-up. This is the most specific test for an intra-articular injury1.
2. The impingement test which involves forced flexion, adduction, internal rotation and axial loading of the hip to recreate hip pain1.
3. Resisted straight-leg rise1.
4. Moving the hip from full flexion, external rotation and adduction to an extended position, internal rotation and adduction which can indicate labral tears and snapping hip syndrome1.

imaging

A provisional diagnosis will be confirmed by an orthopaedic surgeon, ideally using magnetic resonance imaging (MRI) to ensure no avascular necrosis (AVN) is present. The use of MRI imaging also allows for the addition of an intra-articular anaesthetic injection, which an important diagnostic factor when evaluating patients for hip arthroscopy1. Most patients will also have a traditional x-ray of their pelvis too.