summary Hip Osteoarthritis is degenerative disease of the hip joint that causes progressive loss of articular cartilage of the femoral head and acetabulum. Diagnosis can be made with plain radiographs of the hip. Treatment is observation, NSAIDs, and corticosteroids for minimally symptomatic patients. Hip arthroplasty is indicated for progressive symptoms with severe degenerative disease. Epidemiology Incidence hip OA (symptomatic) login to view 1 more bullet knee OA (symptomatic) login to view 1 more bullet Risk factors modifiable login to view 4 more bullets non-modifiable login to view 8 more bullets Etiology Pathophysiology pathoanatomy login to view 19 more bullets Cell biology proteolytic enzymes login to view 6 more bullets tissue inhibitors of MMPS (TIMPs) login to view 2 more bullets inflammatory cytokines login to view 5 more bullets Genetics inheritance login to view 1 more bullet genes potentially linked to OA login to view 8 more bullets Other factors rapidly progressive osteoarthritis (RPOA) login to view 6 more bullets Classification Tonnis Classification Grade 0 Normal radiographs Grade 1 Sclerosis of femoral head and acetabulum Slight joint space narrowing Slight lipping at joint margins Grade 2 Small cysts in femoral head/acetabulum Moderate joint space narrowing Moderate loss of head sphericity Grade 3 Large cysts in femoral head/acetabulum Joint space obliteration/severe narrowing Severe femoral head deformity vs. AVN Presentation History identify age, functional activity, pattern of arthritic involvement, overall health and duration of symptoms Symptoms function-limiting hip pain login to view 2 more bullets pain at night or rest hip stiffness mechanical login to view 1 more bullet Physical exam inspection login to view 4 more bullets range of motion login to view 3 more bullets Neurovascular exam straight leg test negative Imaging Radiographs recommended views login to view 2 more bullets optional views login to view 1 more bullet findings login to view 10 more bullets Studies Histology loss of superficial chondrocytes replication and breakdown of the tidemark fissuring cartilage destruction with eburnation of subchondral bone Treatment Nonoperative NSAIDs login to view 4 more bullets walking stick login to view 1 more bullet weight loss, activity modification and exercise program/physical therapy login to view 5 more bullets corticosteroid joint injections login to view 3 more bullets controversial treatments login to view 3 more bullets recommendation against use login to view 2 more bullets Operative arthroscopic debridement login to view 5 more bullets periacetabular osteotomy +/- femoral osteotomy login to view 5 more bullets femoral head resection login to view 3 more bullets hip resurfacing login to view 3 more bullets total hip arthroplasty (THA) login to view 4 more bullets