HISTORY: A 29 year old female runner and triathlete who developed right hip pain while running a marathon. At mile16 she first noted pain which became severe at mile 24. She completed the race but was unable to bear weight or lift her leg after the race and was not any better the next morning. She required the use of crutches for ambulation and took ibuprofen for pain relief. Upon presentation she had 6/10 pain which was improved since the marathon but she still was unable to ambulate without pain. She denied any low back pain, radiation of pain down her legs, paresthesias, weakness, or bowel/bladder dysfunction. PHYSICAL EXAMINATION: Inability to bear weight on right leg due to pain. There was no tenderness to palpation of the anterior or lateral hip region. Passive internal and external rotation produced pain. Pain with active and resisted hip flexion and knee extension. Full and symmetric strength, sensation and reflexes. DIFFERENTIAL DIAGNOSIS: 1. Stress Fracture of Hip or Pelvis 2. Acetabular Labral Tear 3. Femoral Acetabular Impingement 4. Osteonecrosis of femoral head 5. Iliopsoas bursitis 6. Hip Flexor Tendinopathy TEST AND RESULTS: 1) AP and Frog leg Right hip -no evidence of acute or stress fracture 2) MRI Right hip - incomplete intertrochanteric stress fracture without cortical defect 3) Bone densitometry of the lumbar spine and bilateral hips -No evidence of osteoporosis or osteopenia FINAL WORKING DIAGNOSIS: Intertrochanteric stress fracture, Female Athlete Triad TREATMENT AND OUTCOMES: 1. Non-weightbearing (NWB) with crutches for 2 weeks. 2. Acetaminophen for pain. 3. Consultation with an orthopedic surgeon who agreed with NWB with crutches. 4. Metabolic and energy evaluation revealed that patient had 250-500 daily calorie deficit; otherwise laboratory data was within normal limits. 5. Referred to a sports nutritionist for nutrition counseling and education, including increasing dietary intake as well as supplementation with a Ca 1200mg and Vit D1000 IU daily.