Case Study: Resolving Chronic Sit Bone Pain in a Female Runner

Our Patient

Our patient is a 45 year-old female runner complaining of left sit bone pain when running and sitting. She has a history of proximal hamstring tendinopathy, and had been treated with plasma injections about 5 years prior, along with physical therapy. Her pain was initially resolved by the injections, and she continued to run.

The Challenge

The patient’s pain returned after 5 years, and she was treated with platelet rich plasma (PRP) injected into the proximal hamstring tendon under X Ray guidance. She initially experienced moderate improvement at six weeks after the injection, but her pain returned when she began to run again, along with sensations of tingling and tension spreading to the mid-thigh, and difficulty swinging her left leg.

Our Diagnostic Approach

We conducted a clinical exam and a high-tech running gait analysis to detect the source of the patient’s pain and dysfunction. We also used diagnostic ultrasonography to visualize the patient’s hip and pelvic region in motion.

Our clinical exam revealed:

  • Instability in the left sacroiliac joint
  • Left hip instability
  • Severely weakened muscles in the left gluteus medius, and loss of eccentric control of the deep intrinsic hip rotators
  • Tenderness at and below the semimembranosus at its insertion to the sit bone
  • A positive slump test (an assessment used to diagnose radicular pain originating from the lumbar spine)
  • A positive test for ischio-femoral impingement

Our gait analysis revealed:

  • A tendency to over-stride during running
  • A shorter stride on the left leg
  • Significant foot crossover of the left leg
  • Left pelvic drop

Diagnostic ultrasonography revealed:

  • Fraying of the left long dorsal sacroiliac ligament
  • Thickening of the fascia in the thoracic-lumbar region, and fraying at its insertion to the left ilium
  • Sciatic nerve splitting into tibial and peroneal branches at the piriformis muscle, with no evidence of nerve entrapment
  • Significant fibrotic tissue lateral to the proximal hamstring insertion that was pushing the sciatic nerve towards the lesser trochanter.
  • A significantly enlarged sciatic nerve with an abnormal shape, possibly representing an adhesion due to long-standing proximal tendinosis
  • Abnormal movement of the hip, with the left lesser trochanter trending towards the sit bone
  • Normal ischio-femoral space and normal-sized quadratus femoris


Our Diagnosis

Our diagnosis identified several issues:

  • Severe proximal hamstring tendinopathy with scar tissue formation `
  • Abnormal sciatic nerve mechanics
  • Functional ischio-femoral impingement
  • Sacroiliac joint dysfunction

Why the Patient’s Prior Treatments Failed

The patient’s initial treatment of platelet-rich plasma (PRP) injections five years prior successfully eradicated her symptoms, but no causative factors were established. The physical therapy she received was too general, and not specific to her problem. Since she kept running, her tendinopathy eventually returned and progressed to functional ischio-femoral impingement.


Her second PRP treatment also failed despite being done under Xray guidance, because soft tissues and nerves cannot be visualized with Xray. Her pain returned immediately when she began running again because the treatment addressed the symptoms without identifying the cause. The previous treatments were not ultrasound guided and did not address sciatic nerve mechanics.


In addition, the physical therapy she was receiving included exercises that were compressing the sciatic nerve and creating friction between her thickened hamstring tendon and the sciatic nerve. Such exercises combined with running forty miles a week eventually led to fibrosis of the sciatic nerve. Faulty ischio-femoral mechanics were overlooked, and gait retraining was not even considered.

Our Treatment Approach

  • We performed ultrasound guided extracorporeal shockwave therapy (ESWT) on the proximal hamstring and sacro-illiac ligaments.
  • We incorporated fascia manipulation to release fascia densifications along the retro-medial line.
  • We used ultrasound guided dry needling in the deep sub-gluteal muscles, along the course of the sciatic nerve.
  • Using TECAR therapy and manual mobilization, we improved the elasticity of the hip capsule.
  • We used DNS therapy to promote hip stability.
  • We retrained the patient’s running gait to eliminate over-striding.
  • We provided a home exercise program for hip release and arch muscle training.

Our Results

The patient’s condition improved by 70% within 10 weeks. At that point, we referred her for sciatic nerve hydrodissection, and she was 100% symptom-free after two injections, and back to running to her normal mileage. She remained symptom-free at her 3-month checkup.


Treating symptoms without understanding their underlying cause can lead to further degradation of injured and/or dysfunctional tissues. A thorough and accurate diagnosis is key to rehabilitating patients and restoring pain-free mobility.



In this instance, an athlete was originally diagnosed with minor quadriceps muscle strain and was treated for four weeks, with unsatisfactory results. When he came to our clinic, the muscle was not healing, and the patients’ muscle tissue had already begun to atrophy.

Upon examination using MSUS, we discovered that he had a full muscle thickness tear that had been overlooked by his previous provider. To mitigate damage and promote healing, surgery should have been performed immediately after the injury occurred. Because of misdiagnosis and inappropriate treatment, the patient now has permanent damage that cannot be corrected.

The most important advantage of Ultrasound over MRI imaging is its ability to zero in on the symptomatic region and obtain imaging, with active participation and feedback from the patient. Using dynamic MSUS, we can see what happens when patients contract their muscles, something that cannot be done with MRI. From a diagnostic perspective, this interaction is invaluable.

Dynamic ultrasonography examination demonstrating
the full thickness tear and already occurring muscle atrophy
due to misdiagnosis and not referring the patient
to proper diagnostic workup

Demonstration of how very small muscle defect is made and revealed
to be a complete tear with muscle contraction
under diagnostic sonography (not possible with MRI)


Complete tear of rectus femoris
with large hematoma (blood)


Separation of muscle ends due to tear elicited
on dynamic sonography examination

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