Noisy knees after an anterior cruciate ligament (ACL) injury do not necessarily indicate future arthritis, according to new research from La Trobe University. The study, published in the journal Arthritis Care & Research, emphasizes that the sounds associated with knee crepitus signal existing joint damage rather than a decline in health.
Many individuals experience the usual creaking and popping sounds in their knees. Previous studies suggested that these noises could be linked to conditions like osteoarthritis (OA) in older adults. However, the implications for younger individuals recovering from knee injuries remained unclear.
Jamon Couch, a graduate researcher and physiotherapist at La Trobe, led the inquiry into the relationship between knee crepitus and OA in young adults following traumatic knee injuries. The research involved 112 participants with a median age of 28 years who underwent surgical reconstruction of their ACL. They were evaluated one year after their surgery and again at five years.
Participants were asked about audible knee sounds as part of the Knee Injury and Osteoarthritis Outcome Score (KOOS). Those who reported these sounds “often” or “always” were classified as having crepitus. Additionally, MRI scans assessed cartilage damage, bone spurs, and lesions in the bone marrow.
The findings revealed that one year post-surgery, individuals with crepitus were more than twice as likely to have full-thickness cartilage defects in the patellofemoral joint, located behind the kneecap. They also reported increased pain and poorer knee-related quality of life compared to those without crepitus.
Despite these initial findings, the study indicated that crepitus did not predict worsening joint damage over the following years. From one to five years after surgery, there was no greater risk of progression of OA features observed in MRI scans for those with crepitus. In fact, individuals with crepitus demonstrated greater improvements in pain and function over time, likely due to their poorer initial status.
The study did have limitations, including a small sample size and a relatively low prevalence of crepitus, with only about 21% of participants reporting these sounds. Approximately 30% of the initial cohort returned for the five-year follow-up, which may affect the strength of the associations drawn.
The key takeaway from this research is that while knee crepitus is associated with current joint damage, it should not be viewed as a standalone indicator of inevitable OA progression in young athletes or individuals recovering from traumatic injuries. This insight allows clinicians to reassure patients about their recovery journey.
Encouraging continued physical activity and rehabilitation is vital in countering negative perceptions surrounding crepitus. As Couch noted, noisy knees should not automatically be interpreted as a red flag for future arthritis.
This research contributes significantly to understanding the implications of knee sounds following ACL injuries, offering clarity for both patients and healthcare providers navigating the complexities of recovery and long-term joint health.
