HELP! My Knees are Crackling!

Do you ever notice a crackling or popping sound in your joints? Do your knees creak every time you go down the stairs or do a squat? What’s going on in those joints and is it as bad as it sounds?

The term we use for these crackling sounds in the joints is “crepitus”. Crepitus most often occurs in weight-bearing joints such as the knees but can also be heard in other major joints of the body such as the shoulder, ankle, elbow or neck. These unusual joint sounds may coincide with a crunching sensation or even pain in the area.

Crepitus can occur at any age but is more common as we get older. If the creaking, grating, grinding or crunching sound is accompanied by pain, swelling, redness or tenderness, then it warrants a visit to the doctor for further investigation.

How common is crepitus? In a 2014 study of adults over the age of 40, 17.1% of men and 38.1% of women reported experiencing crepitus in their knee[1].

If the crepitus is NOT accompanied by any signs of inflammation, recent injury, locking, or catching feelings (all of which warrant a visit to the doctor), there are several other possible, more benign things that could be causing your knee noises:

1) Air in the joints – An accumulation of air bubbles in the synovial fluid that lubricates the joints can lead to popping or crackling sounds as the bubbles shift around with our natural movements.

2) Tendons or ligaments moving over other structures – Tendons, which connect muscles to bones, and ligaments, which connect bones to each other, both need to move easily as we bend and straighten our limbs. Sometimes, they can get ‘caught’ over bony areas, protuberances, or other tissues. As they return to their proper place, they may make a snapping or crackling sound.

3) Cartilage injury – If the crepitus came on after a traumatic injury to the joint or area (falling onto the knee, getting hit while playing a contact sport), the sounds may indicate that structures in the area sustained some tissue damage. In most cases, the crepitus will be accompanied by discomfort or pain on weight-bearing or specific movements, but if in doubt, get it checked out!

4) Early signs of Osteoarthritis – Osteoarthritis (OA) is an age-related deterioration of the cartilage within a joint, leading to an inflammatory response and often, pain. Some people develop mild OA without even realizing it. There are many conservative treatment options to slow the development of OA and to improve joint health, including: targeted exercises, lifestyle changes, manual therapy, and even steroid injections into the joint.

In the case of crepitus of the knee, Song et al. (2018) distinguish between ‘physiological noise’ and ‘pathological noise’. Physiological noise may occur with specific movements or activities, but is not accompanied by any pain, swelling, limits to function, or history of trauma to the area. In most cases, it is simply air escaping from the joint fluid, ligaments snapping as they move back into place, extra mobility, or post-operatively as things heal. Pathological noise, on the other hand, corresponds to noise that is associated with pain, swelling, altered function, injury, or difficulty performing everyday tasks. Pathological crepitus should ALWAYS be investigated further in order to treat the root cause and to ensure the well-being and integrity of the joints long-term.

One further note about crepitus. Sometimes we associate creaking joints with age and accept that this is just a natural part of the aging process. However, when our body speaks to us, it’s important to listen. Avoiding the movements that cause crepitus (as long as it’s noise only and not pain) may not be the answer. Maybe our joints are creaking because we haven’t been as active lately, or because we’ve put on extra weight and, in the case of load-bearing joints, they are noticing the heavier load. Or maybe we’ve taken up a new sport or hobby and greatly increased our training routines without adequate time for our body to become conditioned to it.

The Bottom Line: If your joints are speaking to you, LISTEN! And then consider why they might be complaining and how best to address their noisy clamouring.

[1] Song SJ, Park CH, Liang H and Kim SJ. Noise Around the Knee. Clinics in Orthopedic Surgery. 2018 Mar; 10(1): 1-8.