Creaky knees are a common condition that affects a large population over the age of 40 years. Data shows that it has been reported in 38.1% of women over the age of 40 and 17.1% of males in the same age group. (1)
What are Creaky Knees?
Creaky knees are a cause of hundreds of individuals visiting the outpatient healthcare setting every month. It involves noise around the knees as an individual undergoes extension and flexion of the joint. This may also be experienced during squats. This noise is not always associated with a pathological condition but may also be physical in nature. However, studies show that it is more commonly encountered due to a pathological condition. One such study showed that out of the individuals who experienced knee pain and popping sounds, 96.5% were suffering from posterior root tears in the medial meniscus. (2)
Types of Sounds and What They Indicate
The knee sounds are often described using terms like snapping, popping, clicking, crunching, crackling, grinding, grating, clunking, creaking, and catching. These noises may be described according to the frequency, duration, and loudness of the sounds. Even though each sound has its own characteristic and cause of origin, these are collectively known as Crepitus.
Popping Sounds: Popping sounds are used to describe a sudden sharp sound that may be experienced during an injury. This popping noise may originate from the degenerate medial meniscus and detachment of collateral ligaments in the Knee. (3)
Clunking Sounds: Clunking sounds represent a singly loud sound in the Knee, which is caused by a sudden release against resistance. These sounds mostly originate from the patellofemoral joint, after fibrotic nodules are trapped in the junction of the superior pole of the patella and distal quadriceps tendon. (4)
Clicking Sounds: A clicking sound is one of the most common knee sounds and is described as a single tiny click sound that is heard on one cycle of extension and flexion of the Knee. This sound is commonly caused by meniscal tears. (5)
Grinding and Grating sounds: Grinding, and grating sounds may repeatedly occur on the movement of the Knee and are described as ‘continuous scratching sounds. It is commonly experienced by individuals who are diagnosed with Osteoarthritis and Patellofemoral Pain Syndrome or Runner’s Knee. (6)
How To Differentiate between Pathological and Physiological creaky knees?
According to the experts, the best way to differentiate between pathological and physiological knee crepitus is by checking for the presence of any swelling or pain in the knee joint. Individuals with pathological knee crepitus often have a history of knee injury or aggravation of sounds with time. (7)
On the other hand, pathological knee crepitus is almost always associated with pain and swelling along with the onset of the sounds. An example of this is the presence of a loud pop sound during an injury, which indicates damage to the ligaments or meniscus of the knee joint. If Crepitus is associated with joint pain and does not start after an injury, it may be caused by a lesion in the cartilage or rheumatoid arthritis and knee Osteoarthritis. Moreover, pathological sounds can be observed consistently until the pathology is treated. This is not the case with physiological sounds caused by air trapping, which are usually intermittent in nature. (8)
Causes of creaky knees
The knees are the largest joint in the human body and are a site for the union of three main bones known as the Femur, Tibia, and Patella. Sometimes causes as simple as entrapment of air bubbles in the synovial fluid, snapping of ligaments as an individual bends or extends their leg, or catching of the physiological Plica or synovium can lead to Crepitus in the knees. It may also be caused by the presence of a discoid or hypermobile meniscus and the individual perceiving previous sounds even after the treatment due to emotional concerns.
The knees crepitus often occurs in a repeated manner due to the rubbing of anatomical structures against each other. An example of physiological knee crepitus is cracking sounds; however, they are unlike others. This is because these sounds have a refractory period; hence they are not continuously repeated on movement like the others.
A number of reasons have been proposed for the origin of this sound by experts. Some believe that knees creak when a sudden air bubble collapse in the knee cavitation, causing a loud crackling sound. The other believes that it is the formation of the air bubble or clear space that causes the sound. (9) Another type of common physiologic Crepitus is the clicking sound, which is caused by the stretching of ligaments and tendons in the Knee and then eventual snapping back into place as they pass over bony lumps.
Osteoarthritis and Rheumatoid Arthritis
Osteoarthritis and Rheumatoid Arthritis are common causes of Knee Crepitus, as they cause progressive changes in the knee joint. The association between Osteoarthritis and Knee crepitus is heavily studied, and it involves the formation of body cysts and spurs across the joint margins and a slow loss of cartilage. All these changes eventually led to Knee Crepitus. Studies have shown that amongst the individuals who have Crepitus within the KL range of 1 to 3, 80% may be diagnosed with Osteoarthritis of the Knee. (10) Moreover, experts also believe that knee crepitus is an effective assessment tool and predictor of the development of Osteoarthritis in the long term. (11)
Pathological Changes in Plica
Plica is a fold present in the synovium of the joint and represents an embryological remnant of the synovial cavity. Certain pathological changes in the Plica can lead to pain and creaky knees, which include inflammation, thickening, and loss of elasticity. Moreover, studies have shown that increased friction between the Plica and condyle during movement and daily activities may be responsible for these pathological changes and lead to a condition like Synovitis. The type of Crepitus commonly produced by a pathological plica is click sound.
Joint Instability as a cause of creaky knees
Instability in the joint, known as the Patellofemoral joint, is a common factor promoting knee crepitus. This instability may be caused by rotation deformity in the lower extremity, structural anomalies and degeneration of the patella, presence of soft tissue defects in the medial patellofemoral ligament, meniscus tear, chondromalacia, and tightness of the lateral retinaculum. The Patellofemoral instability ultimately leads to hypermobility of the patella or reduction of the subluxated patellar joint. This causes noise upon flexion and extension of the Knee. (12)
Post-Operative Creaky Knees
Creaky Knee may also be experienced by an individual after a surgical procedure involving the knee region. This is particularly true with calcium pyrophosphate crystals starting to get deposited in the joint space. Studies have shown that arthroscopy can increase the chances of knee crepitus due to the inflammation and impingement of a fatty tissue present under the knee cap, known as Hoffa’s fat pad. (13) Other studies have shown that diagnostic arthroscopy may not be the only procedure responsible for a creaky knee, but it may also be caused by meniscectomy and retinacular release procedures. (14)
However, the level of Crepitus caused by surgeries may also vary from patient to patient and the technique used during the surgery.
Management of Creaky Knees
There are a number of ways and techniques that can help treat creaky knees. These methods are mainly aimed at treating the root cause of knee crepitus, which, as discussed above, may be pathological or physiological in nature.
The structures in and around the knees have a poor blood supply, which is why they can struggle to heal on their own. It is the oxygen and nutrients in our blood supply that help to heal these structures.
Prolotherapy involves the injection of a regenerative solution into these structures to provide a direct supply of what is needed to heal them and provide pain relief.
As the treatment is helping to treat the root cause of the problem, it is deemed to be a permanent fix.
Other less effective treatment options –
Management of Physiological Crepitus
The physiological sounds in the Knee are harmless and may be caused by something as simple as gas bubbles popping in the knee space. Hence it does not usually require to be treated, and it may be sufficient to only explain the cause of the sound to the patient and reassure them that there is no underlying pathology.
Strengthening exercises and weight loss may be recommended for the treatment of knee crepitus include, as this helps prevent the snapping of the ligament. These include side-stepping using resistance bands, squats for inner thighs, hamstring stretch, and stretching routines for medial oblique muscle. Therefore, the areas which are a site of focus for these exercises include the hip flexor, calf muscles, and iliotibial band.
Management of Pathological Crepitus
If there is a pathological condition that is responsible for the knee crepitus, daily exercise and weight loss may not be enough. In such cases, there is a need for the treatment of the pathological condition itself, which may either be done using surgical methods or conservative techniques.
For conditions like Osteoarthritis, the patient may benefit by only reducing the inflammation levels in the body. Supplements containing Curcumin, Ginger, and Omega 3 Fatty acids may be therapeutic for this. This may also be accompanied by physical therapy and daily stretching exercises. It may also be beneficial to consult a sports medicine health care professional, especially for popping sounds following a fall or an injury.
Other causes of creaky joints like pathological pika may be treated by excision using arthroscopy. However, it is recommended to opt for the non-surgical procedure before going for surgical removal of the pathological Plica.
The surgical procedure for the treatment of knee crepitus by orthopedic surgeons may help achieve lateral or medial release of patellofemoral ligament, repair of soft tissue compartment, repair of bony compartments, or procedures like tracheloplasty.
The Knee sounds caused by operative procedures may lead to a great deal of dissatisfaction and functional limitation amongst the patients, especially for those with high expectations. Hence, the possibility of knee crepitus is often explained to the patient before the start of the surgery. Moreover, this may also be prevented by asking the patient to follow the medical advice carefully after the procedure. However, these can be treated by conservative treatment methods like anti-inflammatory drugs.
- Ho-Pham, L. T., Lai, T. Q., Mai, L. D., Doan, M. C., Pham, H. N., & Nguyen, T. V. (2014). Prevalence of radiographic osteoarthritis of the knee and its relationship to self-reported pain. PloS one, 9(4), e94563. https://doi.org/10.1371/journal.pone.0094563
- Bae, J. H., Paik, N. H., Park, G. W., Yoon, J. R., Chae, D. J., Kwon, J. H., Kim, J. I., & Nha, K. W. (2013). Predictive value of painful popping for a posterior root tear of the medial meniscus in middle-aged to older Asian patients. Arthroscopy : the journal of arthroscopic & related surgery : official publication of the Arthroscopy Association of North America and the International Arthroscopy Association, 29(3), 545–549. https://doi.org/10.1016/j.arthro.2012.10.026
- Jackson, J. L., O’Malley, P. G., & Kroenke, K. (2003). Evaluation of acute knee pain in primary care. Annals of internal medicine, 139(7), 575–588. https://doi.org/10.7326/0003-4819-139-7-200310070-00010
- Dajani, K. A., Stuart, M. J., Dahm, D. L., & Levy, B. A. (2010). Arthroscopic treatment of patellar clunk and synovial hyperplasia after total knee arthroplasty. The Journal of arthroplasty, 25(1), 97–103. https://doi.org/10.1016/j.arth.2008.11.005