Ischiofemoral Hip Impingement: What Is It and How to Relieve the Pain?

Ischiofemoral Hip Impingement: What Is It and How to Relieve the Pain?

What Is Ischiofemoral Hip Impingement?

Pain in the back of the hip can be a mystery to many, often confused with lower back problems or sciatica. However, there is a specific, little-known but increasingly diagnosed condition: ischiofemoral impingement syndrome (IFP). If you experience pain in your hip, buttocks, or even radiating to your leg, this article will help you better understand this condition, its causes, and treatment options.

Ischiofemoral impingement syndrome occurs when the space between two bony structures in the hip narrows: the lateral part of the ischium (a pelvic bone) and the medial part of the lesser trochanter of the femur. This narrowing can compress the quadratus femoris muscle and, occasionally, the sciatic nerve, causing pain and other symptoms.

Although it has traditionally been associated with previous trauma or hip surgery, more and more cases are being diagnosed without this history, suggesting congenital or biomechanical causes that are not always obvious. It is a condition that can affect both women (more frequently due to anatomical differences in the pelvis) and men, especially if they have a hip deformity known as hip valgus.

How Do I Know if I Have Ischiofemoral Impingement? Identify the Symptoms

The main symptom of FIP is pain in the back of the buttock or hip, which may:

• Worse when sitting for prolonged periods.
• Increase with hip extension or adduction (bringing the leg back or crossing it).
• Radiate to the lower extremity (knee, leg, foot) if there is compression of the sciatic nerve, manifesting as numbness, tingling, or itching.
• Present a "popping" or "cracking" sensation in the back of the hip.
• Cause associated lower back pain due to limited hip extension, which increases pressure on the lumbar joints.

It is essential to differentiate these symptoms from other conditions that cause similar pain, such as sciatica, lumbosacral radiculopathy, piriformis syndrome, or hamstring problems.

How is Ischiofemoral Impingement Diagnosed? Key Tests

Diagnosing FIP can be challenging, as its symptoms overlap with other conditions. An accurate diagnosis often requires a combination of:

• Physical examination: Specific tests such as the "long stride gait" or "ischiofemoral impingement test" can reproduce the pain and provide clues.
• Imaging studies:
  • Magnetic resonance imaging (MRI) of the hip: This is the gold standard diagnostic tool. It allows measurement of the ischiofemoral space (the distance between the ischium and the lesser trochanter) and the quadratus femoris space. It also reveals crucial signs such as edema (inflammation) or fatty infiltration of the quadratus femoris muscle, and even tears.
  • Ultrasonography (US): It has proven to be a very useful tool, complementary to MRI. It allows assessment of the integrity of the deep gluteal muscles and dynamic measurement of the ischiofemoral space (with hip movement). It is also invaluable for guiding injections.

Figure 1: Ischiofemoral and quadratus femoris distance measurements

Figure 2: Quadratus femoris muscle edema (hollow arrow). Sciatic nerve (white arrow).

Figure 3: Quadratus femoris muscle edema

What Is the Best Treatment for Ischiofemoral Impingement?

Treatment for FIP usually begins with conservative approaches, and many patients find significant relief without surgery:

1. What Conservative Therapies Help with Ischiofemoral Impingement?

• Physical Therapy: This is essential. A physical therapist will design a program of stretching and strengthening exercises for the hip muscles (especially the quadratus femoris, piriformis, and hamstrings) to reduce impingement and restore range of motion.
• Medications:
  • Nonsteroidal anti-inflammatory drugs (NSAIDs): To control pain and inflammation.
  • Gabapentin: May be prescribed to relieve neuropathic pain if there is compression of the sciatic nerve.
• Physical Modalities: Application of heat, ultrasound, or interferential current therapies to the affected area.

2. Are Injections Effective for FIP?

If conservative treatment is not sufficient, infiltrations (injections) into the ischiofemoral space or directly into the quadratus femoris muscle can be very effective. These are generally performed under ultrasound guidance to ensure precision and safety. The following are commonly injected:

• Analgesics and corticosteroids: To reduce inflammation and pain.
• Botulinum toxin A: In cases where the quadratus femoris muscle is severely contracted, it can help relax it.

3. When is Surgery Needed for Ischiofemoral Impingement?

Surgery, usually resection of the lesser trochanter, is considered only in severe cases or when conservative treatments have not been successful. It is an option to free the space if bone compression is very pronounced. However, the current trend is to exhaust noninvasive options first, given the good prognosis of conservative treatments.

How to Manage Ischiofemoral Impingement Long-Term?

Early diagnosis of ischiofemoral impingement is key to preventing the condition from becoming chronic. If you experience persistent hip pain, especially with the characteristics described above, consult an orthopedic surgeon or a physical medicine and rehabilitation specialist. A multidisciplinary approach, including physical therapy and, if necessary, injections, can significantly improve your quality of life and relieve pain.