Introduction

The acetabular labrum is a cartilaginous ring which encompasses the acetabulum, deepening the socket and subsequently increasing the stability of the hip joint. An acetabular labral tear results from damage to this cartilage, most commonly occurring on the anterior aspect. Tears may occur due to sudden major trauma to the joint, repeated minor trauma or through chronic 'wear and tear' of the hip joint. Labral tears are a predisposing risk factor for premature osteoarthritis.

The diagnosis of labral tears is increasing since the increasing use of hip arthroscopy. Indeed, labral tears are found in up to 55% of arthroscopies for intractable hip pain.

Epidemiology

  • Incidence: 50.00 cases per 100,000 person-years
  • Peak incidence: 40-50 years
  • Sex ratio: more common in females 1:1
Condition Relative
incidence
Osteoarthritis of the hip10.00
Greater trochanteric pain syndrome6.00
Femoroacetabular impingement4.00
Acetabular labral tear1
Avascular necrosis of the hip0.05
<1 1-5 6+ 16+ 30+ 40+ 50+ 60+ 70+ 80+

Clinical features

The cardinal clinical features of acetabular labral tears are hip pain, locking and instability.

  • Pain
    • Pain is felt in the groin/hip region and is likely to gradually worsen with time. 90% of patients report the pain to be specifically in the anterior hip or groin region.
    • Pain may be exacerbated with prolonged walking, sitting or activity.
  • Mechanical symptoms
    • Clicking, locking, catching and giving way of the hip are commonly reported symptoms in labral tears.
    • Labral tears may also cause a reduced range of movement of the hip joint.

Investigations

Traditional investigations such as hip X-rays, CT-scans, ultrasound and standard MRI are suboptimal at diagnosing acetabular labral tears. X-Rays and CT scans are often normal, however they may show structural skeletal abnormalities such as femoroacetabular impingement syndrome, a condition caused by abnormal bone growth in the hip joint which predisposes individuals to acetabular labral tears. In advanced cases, they may show osteoarthritis. Standard MRI sequences may show perilabral cysts or advanced cartilage lesions.

The two main diagnostic investigations for acetabular labral tears are:
  • MR-arthrogram
    • An MRI scan combined with injecting contrast direct into the hip joint.
    • The best non-operative imaging modality for investigating suspected acetabular labral tears.
    • If the diagnosis remains unclear following MRI, diagnostic analgesic injections may be trialled. If the discomfort and pain respond to the injections, the labrum is the likely source of pain.
  • Diagnostic laparoscopy
    • The gold standard definitive investigation.

Management

Acetabular labral tears may be treated conservatively with physiotherapy +/- medical treatment, or surgically. Given that tears often occur along the articular non-vascular edge, healing potential is limited and surgical management is often required - some studies have argued that there is no role for conservative management in these patients.

  • Physiotherapy
    • Physiotherapy can provide good long term outcomes for treatment of labral tears.
    • Initially, limited activity is advised to minimise pain and discomfort, including the activities that bring on hip pain.
    • Treatment focuses on strengthening the buttocks, thigh, and back, while also improving hip stability.
    • A gradual return to full activities is advocated post physiotherapy.

  • Medical management
    • Physiotherapy my be supplemented with medical therapies, namely NSAIDs, to reduce pain and discomfort.
    • Intra-articular steroid and local anaesthetic injections may also be utilised.

  • Surgical management
    • Surgical management is considered in patients with signs/symptoms of a labral tear for over 4-weeks in conjunction with indicative findings of a labral tear by way of MRI or MRA, or in cases where a labral tear is seen on diagnostic arthroscopy.
    • Hip arthroscopy is the surgical management of choice for acetabular labral tears.
    • The labral tears are undergo either debridement or repair, depending on the pattern and severity of the tear.
    • In addition to elevating symptoms, a key aim of the procedure is to improve the hip joint integrity, reducing the risk future joint degeneration associated with labral tears.