Working Diagnosis:
Ischiofemoral impingement syndrome

Treatment:
Given persistent symptoms despite completion of physical therapy, which provided only mild relief, an ultrasound-guided injection into the quadratus femoris space was performed using 4 mL of 1% lidocaine and 40 mg of triamcinolone.

The patient was instructed to resume physical therapy following the injection, with emphasis on gait modification, hip stabilization, and maintenance of symptom relief through biomechanical retraining. Case Photo #3

Outcome:
The patient experienced immediate pain reduction following the injection, further supporting the diagnosis of ischiofemoral impingement syndrome.

At follow-up, she reported significant improvement in walking tolerance and had returned to hiking without symptoms. Continuation of her home exercise program and completion of physical therapy were recommended to maintain long-term benefit.

Author's Comments:
schiofemoral impingement syndrome remains an underrecognized cause of posterior hip pain, particularly in active older adults, where symptoms often overlap with more common conditions such as lumbar radiculopathy, lumbar spinal stenosis, hip osteoarthritis, and gluteal tendinopathy.1-2

This case highlights the importance of correlating imaging findings with the physical examination, as static magnetic resonance imaging findings alone may not establish symptom causality. Dynamic musculoskeletal ultrasound evaluation with sonopalpation helped localize the pain generator and improved diagnostic confidence.2

Ultrasound-guided injection of the quadratus femoris space served as both a diagnostic and therapeutic intervention in a patient whose symptoms persisted despite multiple prior procedures directed at alternative diagnoses. This case underscores the value of incorporating dynamic imaging assessment and targeted image-guided interventions when evaluating patients with suspected ischiofemoral impingement syndrome.1-2

Editor's Comments:
Ischiofemoral impingement syndrome is an uncommon cause of posterior hip and buttock pain and may be overlooked, particularly in older adults where more common considerations include lumbar spinal stenosis with neurogenic claudication, sacroiliac joint arthrosis, spondylosis, or other degenerative causes of pain. In this patient, the diagnosis became more apparent after a lack of durable response to physical therapy, transforaminal epidural steroid injections, sacroiliac joint injection, piriformis injection, and intra-articular hip injection. This case highlights the importance of maintaining ischiofemoral impingement syndrome in the differential diagnosis of activity-related buttock pain.1-2

A useful physical examination maneuver is the ischiofemoral impingement test (posterior hip impingement test), in which hip extension and adduction performed either in the supine position or while lying on the unaffected side reproduces posterior hip or buttock pain that improves with hip flexion and/or abduction. The long-stride walking test may also reproduce symptoms, as exaggerated stride length narrows the ischiofemoral space and provokes pain that often improves when the patient returns to shorter strides.2

Ultrasound has expanded the evaluation of ischiofemoral impingement syndrome by allowing dynamic assessment of the ischiofemoral space. Ultrasound findings may include narrowing of the ischiofemoral interval during hip extension or external rotation, abnormalities within the quadratus femoris muscle, and reproduction of symptoms with sonopalpation. Dynamic ultrasound may also demonstrate altered motion of the sciatic nerve relative to the quadratus femoris during hip motion. In addition to its diagnostic value, ultrasound can guide targeted injections that serve both diagnostic and therapeutic purposes.2-3

References:
Nakano N, Shoman H, Khanduja V. Treatment strategies for ischiofemoral impingement: A systematic review. Knee Surgery, Sports Traumatology, Arthroscopy. 2020;28(9):2772-2787. doi:10.1007/s00167-020-06097-1.

Wu WT, Chang KV, Mezian K, et al. Ischiofemoral impingement syndrome: Clinical and imaging/guidance issues with special focus on ultrasonography. Diagnostics. 2023;13(1):139. doi:10.3390/diagnostics13010139.

Hatem MA, et al. Ischiofemoral impingement: Normal MRI measurements and clinical significance. Skeletal Radiology. 2020;49:1245-1252.

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