Runner's knee (Patellofemoral pain syndrome)

What is Runner’s Knee?
Runner’s knee is a common term used to describe knee pain around the knee cap. This can actually be one of several conditions, but most commonly it refers to patellofemoral pain syndrome (PFPS) which is an umbrella term used for pain arising from the patellofemoral joint itself.

Each segment of the knee is responsible in supporting and protecting the knee but they also provide assisting support to other ligaments. The 2 main ligaments associated with PFPS are the 2 collateral ligaments lateral and medial as they are merged with the knee capsule. 

What causes Runner’s knee?
PFPS has multifactorial causes such as overuse and overload of their patellofemoral joint, anatomical abnormalities, poor running gait, muscular weakness, imbalance or dysfunction. 

One of the main causes of PFPS is the patella orientation and alignment. A little deviation of the patella can cause muscular imbalances. Conversely muscular imbalances can cause patella deviation. It can also be due to knee hyperextension, lateral tibial torsion, genum valgus (knock knee) or varus (bowlegs), tightness arising from the gluteals, hamstrings, or gastrocnemius. 

Sometimes the pain and discomfort is localised in the knee but the source of the problem is somewhere else such as pronation or supination of the foot. Foot supination provides less cushioning for the leg so more stress goes through the patellofemoral mechanism. Also hip kinematics can influence the knee and provoke PFPS. Weak hip abductors (glutes) are associated with an increase in hip adduction during running, which again can cause issues.

Clinical presentation/characteristics. 
The most common symptom of runner’s knee is anterior knee pain that’s aggravated by activities that increase patellofemoral compressive forces such ascending/descending stairs, running up an incline, sitting with knees bent, kneeling, and squatting.
There is typically a gradual onset to the knee pain.
Running long distances, or increasing the frequency of your runs can cause an excessive overload event.

Potential findings:
Pain when sitting with flexed knee (cinema sign)  - tight quadricep muscles ( sitting they compresses PFJ)  

Pain while sitting with legs crossed  - glute max and TFL tightness

Pain walking downhill  - loads PFJ, muscle length issues, eccentric quads function  

Pain walking uphill  - tight Calf muscles  and Impaired gluteal control  

Pain when wearing high heels  - increases load on PFJ and increases distal instability  

Squat and kneel/ In crouch position  - eccentric quads, muscle length of quads, gluteal control  

Preventing Runner’s Knee
As there are multi factorial causes, there are also multiple ways to prevent this from occurring. Speaking to a trained injury therapist is important before undertaking a specific training programme.
Treatment for runner’s knee can involve trigger point therapy and soft tissue massage to surrounding musculature to release tight muscles.
Sports massage can be complimentary to a training programme to help improve recovery.
Sports therapy to help retrain running gait and strength training to work on weak muscles.