07 May What causes that clicking sound in your knees?

Have you ever wondered why you hear a ‘snap, crackle, and pop’ from your knees when you squat, run, or walk up and down stairs? This is a common problem among people with knee injuries, but also the general population. “Why do my knees make that sound?” is a question our practice often gets quizzed about from our knee patients as well as members at the gym. Noisy knees aren’t usually a cause for concern unless there is pain associated with it. Medically those sounds one may hear is called ‘crepitus’ which refers to that popping or crackling sound in the knee. There are multiple reasons these sounds occur, some of which are the following:

• Gas Bubbles:

Believe it or not but sometime air bubbles can build up in the fluid around your joints. When you move the joint these air bubbles move through a narrow joint space and burst, resulting in the sound you hear in your knee (Kawchuk et al, 2015)

• Ligaments and Tendons:

When moving a joint through various movements the ligaments and tendons surrounding the joint can sometimes move over bone and then ‘pop’ back into place.

• Kneecap tracking:

Due to incorrect biomechanics of the patella (kneecap) can sometimes track incorrectly, causing it to not move along the femoral trochlea (groove of kneecap). The patella will then move over parts of bone that it is not supposed to resulting in the noise heard in the knees (Smith et al, 2012).

• Plica Syndrome:

The plica is a fold in the synovium of the knee joint. It can become inflamed and thickened which reduces its elasticity. It can then rub against the femoral condyle resulting in the clicking sound (Lyu et al, 2015). 

• Osteoarthritis (OA):

Also known as wear and tear, OA often affects the joints you use the most such as your knees. Over time it leads to a breakdown in the cartilage that acts to cushion your joint and results in inflammation, pain, and that crackling sound you hear from your knee as bone to bone contact is made (Schiphof et al, 2014)

There are a number of ways to treat these conditions. A Biokineticist can help strengthen the correct muscles and improve biomechanics to aid in keeping your joints healthy. It is important to keep active as exercise could aid to act as a lubricant for the joints. However, if you have pain along with the noises in your knee, it could be worth it to get it looked at.

References:

Kawchuk GN, Fryer J, Jaremko JL, Zeng H, Rowe L, Thompson R. (2015) Real-time visualization of joint cavitation. PLoS One. 2015 Apr 15;10(4):e0119470. doi: 10.1371/journal.pone.0119470. PMID: 25875374; PMCID: PMC4398549.

Lyu SR, Lee CC, Hsu CC. (2015) Medial abrasion syndrome: a neglected cause of knee pain in middle and old age. Medicine (Baltimore) 2015;94(16):e736

Schiphof D, van Middelkoop M, de Klerk BM, et al. (2014) Crepitus is a first indication of patellofemoral osteoarthritis (and not of tibiofemoral osteoarthritis) Osteoarthritis Cartilage. 2014;22(5):631–638.

Smith TO, Clark A, Neda S, et al. (2012) The intra- and inter-observer reliability of the physical examination methods used to assess patients with patellofemoral joint instability. Knee. 2012;19(4):404–410.