Is further treatment necessary for patellar crepitus after total knee arthroplasty?

BACKGROUND Patellar crepitus may occur with posterior-stabilized (PS) TKAs. Several studies have suggested numerous etiologies of patellar crepitus after PS-TKA with patellar resurfacing. However, it is unclear whether and to what degree crepitus influences pain and function without or with patellar resurfacing. QUESTIONS/PURPOSES We therefore determined (1) the frequency of crepitus; (2) which factors predicted the occurrence of crepitus; and (3) whether crepitus influenced pain and function. METHODS We retrospectively reviewed 41 patients (54 knees) with painful or painless patellar crepitus after primary PS-TKAs without patellar resurfacing performed from 2007 to 2008. These patients were compared with a group of 73 patients (94 knees) without patellar crepitus matched for age, sex, and BMI. The minimum followup was 2 years (mean, 2.8 years; range, 2-4.5 years). RESULTS Five (9%) of the 54 knees with patellar crepitus also had peripatellar pain. Mean time from primary TKA to the onset of patellar crepitus was 4 months. All patients in the patellar crepitus group were asymptomatic within 1 year of onset of symptoms without additional surgical treatment. The development of patellar crepitus was associated with an Outerbridge patellar cartilage Grade 4 (odds ratio [OR], 11.9; 95% CI, 2.2-65.3) and joint line elevation (OR, 5.1; 95% CI, 1.9-8.6). CONCLUSIONS Patellar crepitus is typically benign and self-limited. We continue not to resurface arthritic patellae and counsel patients with patellar crepitus that their symptoms will improve without intervention. LEVEL OF EVIDENCE Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.