Differential Diagnosis for Bone-on-Bone/End-Stage Bilateral Hip Osteoarthritis
- Single Most Likely Diagnosis
- Bilateral hip osteoarthritis with possible subchondral insufficiency fracture of the left femoral head: This diagnosis is the most likely given the description of bone-on-bone/end-stage bilateral hip osteoarthritis and the specific mention of further flattening of the left femoral head, which is consistent with a subchondral insufficiency fracture.
- Other Likely Diagnoses
- Avascular necrosis of the femoral head: This condition can cause similar symptoms and radiographic findings, especially the flattening of the femoral head, and is a common complication in patients with osteoarthritis or those on long-term steroid therapy.
- Osteonecrosis: Similar to avascular necrosis, osteonecrosis can lead to the collapse of the bone structure, mimicking the findings described.
- Rapidly progressive osteoarthritis: This condition can lead to rapid deterioration of the joint, resulting in bone-on-bone contact and significant pain.
- Do Not Miss Diagnoses
- Infection (septic arthritis): Although less likely, infection of the joint can cause rapid destruction and must be considered, especially if there are systemic symptoms such as fever or if the patient has a history of joint injection or recent surgery.
- Malignancy (e.g., metastatic disease to the bone): While rare, malignancy can cause bone destruction and should be considered, especially in patients with a history of cancer or unexplained weight loss.
- Rare Diagnoses
- Paget's disease of bone: This condition can lead to bone deformities and enlargement, potentially affecting the hip joint and causing osteoarthritis-like symptoms.
- Fibrous dysplasia: A rare condition where normal bone is replaced with fibrous tissue, potentially leading to bone weakness and deformity, including in the femoral head.
- Transient osteoporosis of the hip: A rare condition characterized by sudden onset of hip pain due to temporary osteoporosis, which can mimic some of the symptoms and findings of osteoarthritis or subchondral insufficiency fracture.