Buttock Pain - Marathoner

HISTORY: History and Physical Examination: A 50-year-old competitive marathoner presented with sudden onset right buttock pain that started while sprinting during a pub run 3 days prior to presentation. He described the pain as a deep ache that localized just medial to the right ischial tuberosity. Pain was worse with truncal flexion and knee flexion. It was most apparent when walking, but improved when he applied pressure over his ischial tuberosity while walking. He denied weakness and numbness/tingling that radiated down the leg. PHYSICAL EXAMINATION: On examination, gait was not antalgic. There was no bruising, swelling, or change in muscle bulk of the right buttock and posterior thigh. Right hip range of motion was full but end range hip flexion induced pain. He was tender to palpation in the medial and cephalad aspect of the ischial tuberosity with no tenderness over the conjoint tendon or hamstring head of the adductor magnus at the ischial tuberosity. Strength was 5/5 in the bilateral lower extremities, but he had pain with resisted right knee flexion. Sensation was intact in the bilateral lower extremities. DIFFERENTIAL DIAGNOSIS: 1. Hamstring tear or tendinopathy 2. Piriformis syndrome 3. Tear or tendinopathy of the deep hip internal rotators (obturator internus, super gemellus, inferior gemellus) 4. Gluteus maximus muscle injury 5. Sacrotuberous ligament sprain or tear 6. Ischial femoral impingement 7. Sciatic neuropathy 8. Atypical L5 radiculopathy TEST AND RESULTS: Limited diagnostic ultrasound of the right ischial tuberosity region was performed with a 15-6 MHz linear array transducer and showed a normal hamstring without sonopalpation tenderness. The area just proximal and medial to the conjoint tendon origin was exquisitely tender on sonopalpation at the expected site of the sacrotuberous ligament. Cortical irregularity was present on the superior medial ischial tuberosity. FINAL WORKING DIAGNOSIS: Right sacrotuberous ligament sprain TREATMENT AND OUTCOMES: He was referred to physical therapy for right sacrotuberous ligament sprain focused on core strengthening and frequent gentle hamstring stretching. He was pain free after one month and was able to return to running.