Research from La Trobe University indicates that noisy knees, often experienced after an anterior cruciate ligament (ACL) injury, do not predict future arthritis. The study, published in *Arthritis Care & Research* in March 2024, provides reassurance to both patients and healthcare professionals regarding common concerns about knee crepitus, which refers to the grinding, cracking, or popping sounds that some individuals experience.
The study examined the correlation between knee crepitus in young adults following ACL reconstruction and the development of osteoarthritis (OA). The lead researcher, Jamon Couch, a graduate researcher and physiotherapist, emphasized that while noisy knees are associated with current joint damage, they do not signify impending decline. “We found that those with knee crepitus demonstrated more than two and a half times greater rates of full-thickness cartilage defects in the kneecap area, with more pain and poorer function early on,” Couch noted.
In total, the research involved 112 young adults, with a median age of 28, who had undergone surgical reconstruction of their ACL. Participants were evaluated one year post-surgery and followed up at five years. They responded to survey questions about knee noise, which is included in the Knee Injury and Osteoarthritis Outcome Score (KOOS). Responses indicating noise “often” or “always” classified individuals as having crepitus.
Findings on Cartilage Damage and Future Risks
MRI scans were utilized to assess cartilage damage, osteophytes (bone spurs), and bone marrow lesions. The study found that, within a year of surgery, individuals with crepitus were over twice as likely to have full-thickness cartilage defects in the patellofemoral joint, located behind the kneecap. They also reported experiencing greater pain and poorer knee-related quality of life compared to those without crepitus.
Crucially, the researchers found no significant difference between the two groups regarding the progression of OA features on MRI scans from one to five years after surgery. Although those with crepitus initially reported worse outcomes, their pain and function improved over time. This improvement was largely due to their poorer starting point at the one-year mark.
The study does have limitations, including a relatively small sample size and a low prevalence of crepitus, with only about 21% of participants reporting it. Approximately 30% of participants returned for the five-year follow-up, potentially impacting the robustness of the findings.
Implications for Patients and Clinicians
Despite these limitations, the research underscores that knee crepitus in young individuals post-traumatic knee injury is linked to existing cartilage damage rather than indicating future deterioration. Clinicians can use these findings to reassure patients that noisy knees following ACL injuries and reconstructions should not be viewed as a standalone warning sign for future arthritis.
Encouraging ongoing physical activity and rehabilitation can help combat negative perceptions associated with crepitus, promoting a more positive outlook on recovery. As Couch concluded, the study provides crucial insights into the relationship between knee noise and joint health, offering hope for those concerned about their knee function after injury.