The Psoas Impingement is a known complication after a Total Hip Replacement (THR). This issue arises from mechanical irritation of the iliopsoas tendon, often resulting in an inflammatory reaction. A critical factor can be reduced Anteversion of the acetabular implant, limiting the mobility of the hip flexor muscle.

What is anteversion?

The anteversion describes the inclination of the acetabulum forwards. It is crucial to ensure the mobility and stability of the artificial hip joint and to avoid conflicts with surrounding structures. If the anteversion is too low, the anterior edge of the acetabulum can irritate the iliopsoas tendon, particularly during movements like lifting the leg. A suboptimal position of the implant thus increases the likelihood of psoas impingement.

Causes of Psoas Impingement after Hip Replacement

Psoas impingement typically occurs due to:

• Malpositioning of the acetabulum: Particularly, a reduced anteversion or a too shallow position of the acetabulum increases mechanical friction.
• Overhang of the acetabular rim: An overhang irritates the tendon.
• Muscle atrophy or weakness: A weakened iliopsoas often leads to dysfunctional stress that overstrains the tendon.
• Presence of foreign body reactions: Tissue reactions to the implant material can additionally promote pain.

Classic symptoms of psoas impingement

Patients with psoas impingement suffer from the following symptoms:

• Groin pain: This occurs particularly when lifting the leg (flexion) and when sitting down. The pain can become chronic and intensify the longer the irritation persists.
• Strength Limitations: Patients often report weakness in the hip flexor muscle, making everyday movements like climbing stairs or lifting the leg more difficult.
• Clicking sounds: Occasionally, those affected feel or hear a snapping when the tendon glides over the edge of the acetabulum.
• Limitations in Daily Life

Diagnosis of Psoas Impingement

The following methods are used for a reliable diagnosis:

• Clinical Examination: The doctor checks for typical symptoms such as groin pain during passive hip flexion and rotation.
• Diagnostic infiltration: The tendon is injected with a local anesthetic. If the symptoms temporarily disappear, a psoas impingement is likely.
• Imaging Techniques
• Ultrasound Examination
• MRI

Treatment Options for Psoas Impingement after Hip Replacement

There are various approaches to treating psoas impingement:

Conservative Therapy:

• Physiotherapy: Specific exercises to strengthen and mobilize the iliopsoas can alleviate symptoms. Professional guidance is crucial to relieve the muscle and avoid incorrect movements.
• Medicinal treatment: Anti-inflammatory medications (e.g., NSAIDs) help reduce swelling and pain.
• Injections

Surgical Therapy:

• Acetabular Revision
• Tendon release: In severe cases, the iliopsoas tendon is surgically lengthened or relieved. However, this procedure should be carefully considered, as it can cause functional limitations.

Prevention of Psoas Impingement

• Optimal implant positioning: Precise planning of the cup and shaft position can avoid complications. The correct anteversion position is particularly relevant here.
• Relief and Rehabilitation
• Regular follow-up checks: Follow-up examinations can detect and treat incipient psoas impingement at an early stage.

Conclusion

Psoas impingement is a frequently underestimated but serious complication after a total hip replacement (THR). Early diagnosis and individually tailored therapy are crucial to reduce pain and functional limitations. Thanks to modern surgical methods and improved implant technologies, many problems can be avoided in advance. The Endoprotheticum Mainz specializes in the optimal care and follow-up of patients with hip prostheses and offers comprehensive advice and treatment options.