• Subjective crepitus of the knee joint predicts symptomatic knee osteoarthritis.
• Symptomatic knee osteoarthritis developed most frequently in those with prior radiographic osteoarthritis.
• Knee crepitus was predictive of knee pain within a year and over 4 years.
• In patients without radiographic evidence of osteoarthritis but with knee crepitus, symptomatic knee osteoarthritis was more likely to result over a longer term than the 1 year of follow-up in this study.
Osteoarthritis is a leading cause of pain and disability in the United States: 16% of Americans older than 60 years suffer from symptomatic knee osteoarthritis.
Grace Lo and fellow researchers at multiple US medical centers point out that although cracking and popping in the knee joint on clinical exam is regarded as a sign of progressive joint arthritis, it is unknown whether patient subjective reports of crepitus are indicative of impending symptomatic knee osteoarthritis.
The researchers sought to identify an association between subjective knee crepitus and the development of symptomatic knee osteoarthritis.
The authors performed a person-based longitudinal study looking at data from the Osteoarthritis Initiative (OAI) database.1 Records were screened for right knee crepitus, and follow-up was examined for symptomatic knee pain and radiographic evidence of osteoarthritis. Ultimately 3495 patients were included in the analysis.
• Crepitus was reported as: none, rarely, sometimes, often, and always with prevalence being reported as 7313 (65.1%), 1213 (10.8%), 1701 (15.1%), 626 (5.6%), and 384 (3.4%), respectively.
• On first visit, crepitus was associated with pain score (R = 0.33; P < .0001).
• There was no association between crepitus and radiographic Kellgren/Lawrence (K/L) grading (R = 0.03; P = .1).
• The odds of developing symptomatic osteoarthritis increased significantly with increasing frequency of crepitus (P < .0001).
• The incidence of symptomatic osteoarthritis in those with radiographic osteoarthritis but without symptoms at baseline was 45.0%; in those without radiographic osteoarthritis but with symptoms at baseline, 10.2%; and in those without radiographic osteoarthritis or symptoms at baseline, 4.6%.
• In all groups, crepitus and pain scores were correlated (P < .001), but crepitus and K/L scores were not (P = .7).
Implications for physicians
• Ask patients about the presence of crepitus on routine office visits.
• Take reports of joint crepitus seriously, especially in aging patients.
• Radiographic examination may help identify patients at risk for subsequent joint osteoarthritis following asymptomatic crepitus reports.
• Identification of impending symptomatic osteoarthritis may help prevent pain and disability; however, more research is needed.
The Center for Innovations in Quality, Effectiveness, and Safety provided funding for this project.
1. Lo GH, Strayhorn MT, Driban JB, et al. Subjective crepitus as a risk factor for incident symptomatic knee osteoarthritis: data from the Osteoarthritis Initiative. Arthritis Care Res. 2018;70:53-60.