Acetabular or hip labral tear (labral tear) refers to the rupture of the labrum, the cartilaginous rim that covers the acetabulum at the pelvis.
The labrum is a critical structure of the hip joint as it stabilises the femoral head within the pelvic socket or acetabulum. One side of the labrum connects with the pelvis capsule and its ligaments and the other side with the head of the femur. This intra-articular side is poorly vascularised and difficult to heal after injury or surgery.
A tear to the hip labrum mostly occurs with repetitive injury. It consists of a gradual process facilitated by a condition named femoral acetabular impingement, involving a reduced clearance between the femoral head and neck with the acetabulum. With repetitive internal rotation of the hip, the impinged labrum is subjected to increasing pressure, which over time leads to its rupture. In extreme cases this pressure can lead to the total avulsion of the labrum from the acetabulum.
There are various classification systems for a shoulder impingement syndrome.
Stages of subacromial impingement in athletes - Jobe’s Classification
Pure impingement with no instability
Primary instability, with capsular and labral injury with secondary impingement, which can be internal or subacromial impingement
Primary instability due to intrinsic ligament laxity with secondary impingement
Pure instability with no impingement.
Grading of impingement changes - Milgrom’s Ultrasound Classification:
Stage 1 Bursal thickness from 1.5 to 2.0 mm
Stage 2 Bursal thickness over 2.0 mm
Stage 3 Partial or full thickness tear of the rotator cuff.
Impingement lesions - Copeland Levy Classification:
This is based on the location of the impingement, either on the acromial or the bursal side.
A0 normal - smooth surface
A1 minor deterioration, haemorrhage or local inflammation
A2 marked scuffing/damage of the undersurface of the acromion and coraco-acromial ligament
A3 exposed bone areas.
B0 normal - smooth surface
B1 minor deterioration, haemorrhage, inflammation
B2 major deterioration of the cuff, partial thickness tear
B3 full thickness tear of the rotator cuff
B4 massive cuff tear.
According to the Habermeyer Classification the fractures to the proximal humerus are divided into:
Type 0 one fractured part without dislocation
Type A two-part fracture of the great tuberosity and lesser tuberosity avulsion
Type B involves the humerus “surgical” neck below the femoral head as two-part, three-part and four-part with one or both tuberosities
Type C involves the humerus anatomical neck (between the head and greater tuberosity) as two-part, three-part and four-part with one or both the greater and lesser tuberosities.
These are defined further as:
One-part fractures are non-displaced fractures or fractures with minimal displacement
Two-part fractures only involve a single segment
Three-part fractures involve two segments
Four-part fractures occur when all humeral segments are involved (see image in pathology section)
The injury severity is proportional to the increasing number of fractures.
The aetiology of a hip labral tear is mostly unknown. The diagnosis is occasionally achieved without evident symptoms. The main causes include trauma and sport injuries. In sports the involvement of internal rotation of the hip with sudden changes of direction and twisting seem to be the origin of a labral tear of the hip. This pathology is also the consequence structural or congenital changes of the hip that weaken the joint stability. Known causes are:
Trauma (falls, motor vehicle accidents)
Sport injuries (golf, ice hockey, soccer, football, running, sprinting, ballet)
Capsular laxity (loose ligaments)
Cam lesion (bony protrusion) on the femoral head causing impingement
Pincer impingement: presence of extra bone (spur) at the rim of the acetabulum
Combination of CAM and Pincer
Hip osteoarthritis in the elderly
A number of risk factors have been attributed to the development of hip labral tear:
Congenital hip dysplasia
Hip joint degeneration (osteoarthritis)
Although often asymptomatic, the symptoms of a hip labral tear include the following:
Pain to the groin area, buttock and anterior side of the hip
Pain increasing with movement
Pain with prolonged standing, sitting and walking
Pain becoming evident at rest
Noise e.g. clicking, locking, or catching of the hip with movement
Stiffness of the hip
Instability of the hip
Difficulty in walking, limp
The diagnosis of a hip labral tear is not always straightforward as its symptoms are similar to those of other hip pathologies. The clinical examination begins with the medical history to acquire information on injuries, life style, sport activities, or previous diagnosis of hip structural deficiencies that may increase the risk of a labral tear of the hip. The examiner will assess any changes in the range of movement of the hip, its stiffness, muscle discrepancy and gait abnormalities such as a limp.
A positive Trendelenburg test is a sign of the pathology whereby the hip with a labral tear drops when standing on the opposite leg. Another tests is the impingement sign, consisting of flexing the hip to 90º, turning the hip inward with internal rotation and bringing the thigh towards the opposite hip (adduction).
X-rays are taken to establish possible structural abnormalities in the hip joint and MRI scans to detect changes of the labrum itself, tendons, ligaments and capsule. A specific MRI named magnetic resonance arthrography (MRA) is more accurate as it improves the image quality following local injection of the contrast agent gadolinium.
Conservative treatment is considered more relevant today than before when surgical removal of the labrum was performed leaving the hip unsupported.
The nonoperative approach is mostly based on physical therapy to reinforce the muscles around the hip and modify posture, movement and alignment assessed with precise gait analysis. Acutely, iIt is advised to minimise weight bearing with the use crutches. The movement of the hip can be corrected with the use of a SERF strap (Stability through External Rotation of the Femur) that is applied around the thigh, knee, and lower leg to support the hip during movement by keeping it into external rotation. Additional conservative treatment includes:
Pain management with analgesics
Anti-inflammatory drugs (NSAIDs)
Local steroid injection
With more severe damage to the hip labrum or failure of conservative therapy, surgery is recommended. The surgical approach mostly relies on hip arthroscopy, which is used also as a diagnostic tool. The purpose of hip arthroscopy is multi-fold:
Labral refixation used to reattach the disconnected labrum to the edges of the acetabulum using suture and screws
Debridement of the labrum; when greater damage of the labrum occurs and cannot be salvaged, part of the cartilage is debrided (removed) to avoid that it interferes with the movement of the hip causing pain.
When severe hipbone abnormalities are present or in case of femoro-acetabular impingement, open hip surgery becomes necessary to resolve the complexity of the pathology.
Physical therapy is indicated following a short period of rest and guided by a physiotherapist. With a successful conservative treatment for minor labral tears the prognosis is up to 6 weeks whereas following surgery for more severe labral tears up to 8 weeks or longer.
The intensity of physical exercise is increased in accordance with the improvement of symptoms. The aim of physiotherapy is to improve joint flexibility and strengthening the pelvis, glutei and thigh muscles to stabilise the hip. Physiotherapy management also includes:
Antiinflammatory therapy (NSAIDs)
Use of crutches
Exercise in the pool to reduce stress on hips
Activity modifying regime
Return to activity plan
The most effective prevention for a labral tear of the hip involves the modification of activities during strenuous sport that increase the risk of the pathology. In such activities it is recommended to keep the entire musculature around the hip well toned and flexible. It is important to avoid loading the hip with full body weight especially when the legs are at maximal aperture from the normal range of the hip.