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.