What is special about the hip joint and what happens when it malfunctions?
The hip joint is a ball-and-socket joint that runs along the acetabulum, allowing full movement in all three directions. Disorders of the hip joint can be caused by either a misalignment of the femoral head or the acetabulum, and are often manifested by load-dependent pain.
In both cases, a mechanical problem occurs when the head-neck transition of the femoral neck strikes the anterior glenoid cup, which can damage both the labrum and the articular cartilage, often leading to joint arthrosis.
Why is a comprehensive examination by a specialist so important?
As well as wear and tear of the hip joint (osteoarthritis), other damage and conditions close to the joint need to be looked at. It is not uncommon to find damage to the labrum.
What is the function of the labrum?
The labrum surrounds the hip joint and protects the free cartilage edge of the hip joint. This allows the joint surface to be enlarged and keeps the fluid film (synovia) in the joint space. As a result, low-friction movement is possible and wear on the joint is delayed. If the labrum is damaged due to misalignment, it will tear, similar to the meniscus tear in the knee joint.
Why should groin pain (when sitting) be taken seriously?
Pain in the groin is caused by the nerve supply to the labrum during stress or certain movements. The labrum becomes irritated. As most labral tears are in the anterior (front) region of the hip socket (62-92%), this is indicated by groin pain when sitting during daily activities.
Figure 1: Degenerative labral tear of the anterior acetabulum (left), labrum detached from the acetabulum (right).
When this pain occurs, there is often a mechanical problem. In addition to the damage to the labrum, the articular cartilage becomes detached and exposed. The increased shearing forces on the cartilage can cause further damage, leading to osteoarthritis of the hip joint.
Figure 2: Loosened articular cartilage from the acetabulum in a severe labral defect with cam impingement.
What tests are performed in the clinic?
If labral damage is suspected, a magnetic resonance imaging (MRI) scan of the affected hip joint should be performed during the clinical examination. This involves injecting a contrast agent into the hip joint (MR arthrography). This method has a much higher sensitivity (92%) than standard MRI (62%).
Figure 3: MR arthrography showing labral damage in the hip joint.
Conservative or surgical? Why is surgery recommended?
Conservative treatment of labral tears is usually unsuccessful. Surgery can be performed by arthroscopy without causing major deformity of the hip joint. The damage is repaired through two to four small skin incisions using small instruments. Depending on the size of the defect and the nature of the labrum, the procedure may involve smoothing with removal of degenerative parts of the labrum or reconstruction with suturing of the labrum.
How much time will I spend in hospital and when will I be able to get back to work?
Follow-up treatment after arthroscopy of the labrum depends on the initial damage and the surgical treatment given. However, in many cases the patient will be able to do pain management and physiotherapy exercises on the first day after surgery. If additional work was done on the joint cartilage or bony structures during surgery, partial weight bearing is often required. Aftercare always depends on the individual case.
What are the scientific results?
The results of clinical studies show that arthroscopic treatment of isolated labral tears results in significant improvement in a large number of cases. Byrd et al showed that 83% of patients had good to excellent results. Similar results were found by Streich et al, Nepple et al, Yamamoto et al in their patient populations where they treated labral tears arthroscopically.
As a result, arthroscopic treatment of labral damage in the hip joint is now the first choice and offers patients a very good chance of improvement.