Steroid Injection for Patellofemoral Pain Syndrome

Patellofemoral Pain Syndrome is a term used to describe a condition where mal-tracking of the joint or excessive pressure in the joint surface causes pain on activities that load the knee. In the running athlete, this is often referred to as “runners knee”. 

Causes

The cause of this condition can be multifactorial. There is no common consensus of its origin but is often associated with weakness in the quadriceps and hip abductor muscles (Petersen, et al 2014, Thomee, et al 1999) and may also include:

• Poor running biomechanics
• Muscle tightness eg in the calf, hamstring, ITB or quadricep muscles.
• Inappropriate running shoes
• Early degenerative changes to the joint cartilage
• Sudden increase in training load
• Hill running

If the patella is subjected to forces that cause it to tilt or glide more in one direction than it is designed to then over cumulative loading damage to the joint can occur causing the pain.

Symptoms of Patellofemoral Pain Syndrome

The Most common symptoms of PFPS are: 

• Pain climbing stairs
• Pain with running which may ease initially in the run then worsen with distance and after the run
• Pain sitting with the knees bent eg going to the cinema or on a flight
• Pain cycling

Anatomy

The Patellofemoral joint is the joint between the knee cap (Patella) and the thigh bone (femur). The patellar is designed to slide in the groove of the femur and distribute force from the Quadriceps tendon via the Patellar tendon onto the shin bone (Tibia). The joint is under most load when we straighten the knee from a bent position. The back of the patella is “V” shaped to improve its stability in the groove and hence should give evenly on all surfaces. It also has bands of stabilising fascia which is thick fibrous connective tissue to help stabilise the patella when sliding in its groove.

The other main stabilising structure of this joint is the quadriceps muscle “Vastus Medialis Obliqus” (often referred to as VMO). The muscles role is to prevent excessive lateral tracking of the patellar which is a common cause of PFPS. The VMO can often be dysfunctional after an injury or surgery which can lead to pain in this joint.

If the balance around the stabilising structures is altered it can lead to excessive pressure on one of the surfaces which can lead to pain.

How to diagnose

If you have some of the classic signs of PFPS mentioned above and it is not easing on its own then one of our clinicians can carry out a biomechanical assessment on the patellofemoral joint to identify the cause of the condition.

They will also perform some special tests on the knee to identify the source of the pain and ensure it is not something more structural like a meniscal tear or tendon problem.

We can use a diagnostic ultrasound scan to assess the knee dynamically and look for swelling and thinning of any cartilage in the joint and any other obvious pathology that might be causing the pain.

Treatment

PFPS is usually successfully treated with Physiotherapy and surgical intervention is almost never appropriate (Petersen, et al 2014). Evidence suggests that exercise therapy is consistently the most appropriate treatment (Gaitonde, et al 2019) which may include:

• Quadriceps, gluteal and core strengthening exercises
• A video gait analysis to identify poor biomechanics which may be contributing to the condition
• A short period of rest from aggravating factors ie no running and doing exercises focusing on the back of the legs
• A short course of NSAIDs has been shown to be of use for short term relief
• Soft tissue therapy around any structures that may be contributing to the load on the patellofemoral joint
• Taping and bracing have also consistently been found to help alleviate some of the pain associated with this condition (Sisk,  et al 2020). We can use tape and show you how to tape yourself for sport and exercise.  

Patellofemoral Pain Syndrome Steroid Injection therapy

Unfortunately if there is inflammation in the joint and things have not settled with conservative measures then you may wish to explore other treatment options to help settle the joint inflammation down. An ultrasound guided steroid injection into the joint is occasionally required especially if there is joint swelling that is not easing.

A steroid injection for PFPS is only required to bring down any inflammation in the joint. It will not fix the biomechanics or degenerative cause of the condition, so it is important to still continue with your Physiotherapy rehabilitation exercises as well.

Ultrasound-guided corticosteroid injection
This is a  small dose of corticosteroid (a strong anti-inflammatory drug) that we inject into the knee joint with Ultrasound-Guidance. It is a quick and simple procedure that is usually well tolerated but is a last resort for persistent PFPS. 

Other options to consider for persistent PFPS are Hyaluronic acid injections. 

Ultrasound-guided hyaluronic acid injection
Hyaluronic acid (HA) is naturally present throughout the human body and provides lubrication to eliminate friction of the joints. Injecting HA can help improve lubrication and shock absorption of the knee joint and has a weak anti- inflammatory effect.  There is positive evidence for the use of Hyaluronic acid injections for patellofemoral pain syndrome (Tamburrino, et al 2016), but there is also research showing minimal difference to a “sham” injection (Hart, et al 2019). However there is a lot more research supporting Hyaluronic acid injections for Osteoarthritis in the knee (Phillips, et al 2021) and therefore if your Patellofemoral joint has any degree of degeneration which is similar to Osteoarthritis then it may be a suitable option for you.    

Other Knee Conditions:

• Iliotibial Band Friction Syndrome
• Knee Osteoarthritis