Patellar crepitus is a complication of total knee arthroplasty (TKA).The development of patellar crepitus after TKA are related to many factors such as femoral component design, surgical errors, and postoperative patellar baja. However, it is unclear whether patella resurfacing or patella non-resurfacing are associate with patellar crepitus. The primary objective of this study are to compare the prevalence of patellar crepitus and the mean value of vibroacoustic signal between patellar-resurfacing and patellar non-resurfacing in TKA. The secondary objective is to study the association between patellar crepitus and vibroacoustic signal.

Inclusion Criteria:

• primary osteoarthritis of knee

Exclusion Criteria:

• rheumatoid arthritis
• morbid obesity
• severe patellofemoral joint destruction
• patella maltracking
• patellofemoral incongruent
• inflammatory arthritis
• refuse to participation