Differential Diagnosis for Older Male with Hip Pain and Outward Leg Rotation

• Single most likely diagnosis
  • Osteoarthritis of the hip: This is a common condition in older adults, characterized by wear and tear of the hip joint, leading to pain and limited mobility. The outward rotation of the leg is a typical posture adopted to reduce pain.
• Other Likely diagnoses
  • Avascular necrosis of the femoral head: This condition occurs when the blood supply to the femoral head is disrupted, leading to necrosis of the bone tissue. It can cause hip pain and outward rotation of the leg.
  • Trochanteric bursitis: Inflammation of the bursa over the greater trochanter can cause hip pain and outward rotation of the leg.
  • Hip fracture: A fracture of the hip, such as a femoral neck fracture, can cause hip pain and outward rotation of the leg, especially in older adults with osteoporosis.
• Do Not Miss diagnoses
  • Septic arthritis of the hip: This is a serious infection of the hip joint that requires prompt treatment. It can cause hip pain, fever, and outward rotation of the leg.
  • Metastatic bone disease: Cancer that has spread to the bone can cause hip pain and outward rotation of the leg.
• Rare diagnoses
  • Pigmented villonodular synovitis (PVNS): A rare condition characterized by inflammation of the synovial membrane, leading to hip pain and stiffness.
  • Synovial chondromatosis: A rare condition characterized by the growth of cartilage in the synovial membrane, leading to hip pain and stiffness.
  • Osteonecrosis of the femoral head due to other causes (e.g., sickle cell disease, steroid use): These conditions can cause hip pain and outward rotation of the leg, although they are less common than other diagnoses.