Baker's cyst: how I treat it?

Baker’s cyst: what it is, causes and treatment

Baker’s cyst, also known as a popliteal cyst, is a condition generally associated with musculoskeletal disorders of the knee such as osteoarthritis and meniscal tears, which makes it very common. It affects both adolescents and adults. In adolescents it is rare and often has no specific cause (it is discovered by chance during routine tests or check-ups). In adults, however, a Baker’s cyst can be a source of pain at the back of the knee and, in 94% of cases, it is found alongside the joint problems mentioned above. I will therefore guide you through what it is, what causes it and what to do if you think you may have one.

Baker’s cyst: what is it?

So what exactly is a Baker’s cyst? It is a cyst behind the knee that is actually always present, but fills with fluid when the knee is inflamed. This cyst, or bursa, communicates directly with the knee joint through an opening in the joint capsule that surrounds the knee. It is precisely this anatomical feature that creates a valve-like mechanism: when there is inflammation, an effusion forms and fills the bursa with fluid. There is no need to worry, however, as this is a normal protective mechanism that the body uses to reduce the pressure inside the knee joint.

Baker’s cyst: causes

In adolescents, the causes of a Baker’s cyst are mechanical, mainly due to excessive friction of the knee flexor tendons, for example during periods of overload. So if you are young and play sport, it is worth reviewing your recent training load. In adults, a cyst at the back of the knee is almost always (in 94% of cases) associated with an intra-articular knee condition, the most common being osteoarthritis and meniscal tears. If you recognise yourself in this group, start thinking about the medical history of your knee.

Baker’s cyst: diagnosis and treatment

I recommend learning more about the diagnosis and treatment of this cyst so that you can resolve the problem as soon as possible. A physiotherapist can certainly guide you in understanding the underlying causes and suggest early, effective treatment for a cyst behind the knee. You can be reassured that cysts are only occasionally associated with serious conditions that require immediate medical attention, such as osteochondritis dissecans or arthropathy (seronegative or seropositive), or a simple meniscal tear. In adults, a Baker’s cyst typically presents with a vague pain at the back of the knee, possible localised swelling and a feeling of tightness in the popliteal region (the area behind the knee).

In most cases, your physiotherapist will find a palpable mass in the popliteal region (you can see a cyst behind the knee). Several diagnostic tests can help confirm the diagnosis, first and foremost an MRI scan, which also allows any related intra-articular conditions to be assessed. An ultrasound scan is nevertheless recommended, as it is less costly and more readily available.

Baker’s cyst: is physiotherapy needed?

Is physiotherapy needed for a Baker’s cyst?

Once vascular or neuropathic causes and any serious conditions have been ruled out, treatment for the first six weeks should be physiotherapy rather than surgery. Physiotherapy for managing a Baker’s cyst is extremely useful for promoting flexibility in the knee, reducing stiffness and maintaining the full range of movement. That said, don’t waste time: contact a physiotherapist in your area.

Physiotherapy can also be combined with injected anti-inflammatory medication. If physiotherapy and other conservative treatment fail, minimally invasive treatment is recommended, consisting of ultrasound-guided aspiration of the fluid from the joint (together with an anti-inflammatory injection). This has shown excellent results with minimal risk.

If minimally invasive treatment of the cyst is not enough, the cyst can be removed by arthroscopic surgery. However, removing the Baker’s cyst surgically without treating the intra-articular damage to the knee tends to lead to recurrence, so it is advisable to treat the underlying joint condition alongside the excision.

Conclusion

As we come to the end of this article, I would like you to focus on a few key points to bear in mind if you think you may have this condition.

First, stay calm. A Baker’s cyst almost never hides a serious condition; in 94% of cases it is associated with the most common knee problems (osteoarthritis, tendinitis, meniscal degeneration, etc.). Second, don’t waste time: contact a physiotherapist you trust, who can help you understand the causes of your problem and intervene early for a complete resolution. The right conservative treatment resolves the problem without the need for surgery.

References

Herman AM, Marzo JM. Popliteal cysts: A current review. Orthopedics. 2014.Hill CL, Gale DG, Chaisson CE, Skinner K, Kazis L, Gale ME, et al. Knee effusions, popliteal cysts, and synovial thickening: Association with knee pain in osteoarthritis. J Rheumatol. 2001.