Knee Bursitis is defined as inflammation of the bursa or bursae surrounding the knee joint. There are bursae – small, contained sacs of fluid – around every major joint in the body, including the knee, hip and shoulder. Their normal function is to reduce friction between muscles, bones and tendons at these joints and facilitate smooth, fluid and pain-free movement. When they become inflamed, they can enlarge significantly and become painful and tender to touch. This is the phenomenon referred to as “bursitis”.
Knee bursitis has numerous different causes that range from the least serious such as idiopathic causes, underlying osteoarthritis, repetitive straining of the muscle or joint around which the bursa is located and simple muscle fatigue to the more serious such as infection, rhabdomyolysis, local trauma and potentially even undiagnosed malignancy. Fortunately, the most serious causes are exceptionally rare and the vast majority of bursitis cases are simple, and treatable.
Bursitis usually presents as pain in and around the knee. It is often described as a burning sensation, although it can be felt sharply in certain areas as well. The best way to differentiate bursitis pain from generalized muscle or joint pain such as from osteoarthritis is try and localize the pain to a specific area around the joint.
Pain that localizes to a specific area is much more likely to appear as a result of bursitis, especially if the area that is localized is known to have a bursa directly underneath the point of maximal tenderness (e.g. the pes anserine bursa, the prepatellar bursa). Osteoarthritis pain is much more generalized and far more difficult to localize with the patients typically describing this as more of a global sensation around the whole joint itself rather than pinpointing it to a specific spot.
Activity and weight bearing will typically worsen the pain experienced from bursitis, especially activity of the muscles that directly interact with or are directly adjacent to the culpable bursa. For example, a prepatellar bursitis will worsen with extension and flexion of the knee joint and activation of the quadriceps/hamstring mechanism, whereas pes anserine bursitis will be specific to flexion of the knee, in particular the hamstrings, and be localized to the anteromedial aspect of the joint.
Treatment of Knee Bursitis if often not necessary, as the condition is self-limiting in the majority of cases and will resolve with cessation of the provoking factor (e.g. sitting and resting after prolonged standing/walking). On occasion more active treatment measures are required such as anti-inflammatory medications. These can be taken orally or applied topically to the area until symptoms resolve. Refractory or recurrent cases can be treated with an injection of corticosteroid (a more powerful anti-inflammatory) directly into the bursa itself.
This carries a small risk of infection, as with any injection, but is often very effective at treating pain that has persisted beyond standard treatment measures. Knee Bursitis can also be treated very effectively with a dedicated physical therapy regimen involving stretching and muscle strengthening exercises around the knee joint. Surgical intervention for knee bursitis is exceptionally rare, and usually not necessary.
Most patients should notice that the bursitis settles down within several weeks, whether this is due to the activity modification or whether this is due to the commencement of a course of anti-inflammatory medication. If neither of these are effective after 3 or 4 weeks then consideration of an injection should be given.
If the patient does wish to proceed with injection as an intervention then typically these injections will take several days to become effective and should provide significant pain relief that will hopefully be semi-permanent in nature (i.e. may very well relieve the pain in its entirety, although there is a small risk that the bursitis will return with repeated activity in the future).
Knee Bursitis is a very common complaint amongst adults of all ages and activity levels. Even when requiring active treatment, it is fortunately usually very responsive and seldom recurrent and problematic. If you are experiencing symptoms you think may be consistent with knee bursitis and would like to discuss them with a healthcare professional, contact our office for a consultation with one of our surgeons.