Runner's Knee(Patellofemoral Pain Syndrome): Causes, Symptoms, Diagnosis and Treatments

What is patellofemoral pain syndrome (Runner's Knee)?

Patellofemoral pain syndrome refers to pain in front of the knee. It is most commonly seen in teenagers, athletes (runner's knee) and manual labourers. The kneecap has a cartilage underneath that acts as a natural shock absorber. The disorder is generally also referred to as chondromalacia patella, or damage to the cartilage under the kneecap.

What are the causes of the disorder?

The patella or the kneecap is a small, triangular bone present in front of the knee. It moves along with the knee as it flexes, gliding up and down along a trajectory at the end of the thighbone (femur), while allowing the front thigh muscles (quadriceps) to extend the legs further. The patella is also responsible for protecting other bones of the knee against falls and collisions. The patellofemoral pain syndrome is caused by injury, overuse, excess weight, improper alignment of the kneecap (patellar tracking disorder), or changes under the kneecap. Patellfemoral pain syndrome is most commonly identified when a person starts a new physical activity or increases the intensity of an existing activity (like in high-impact sports). The disorder also affects non-active people during their daily activities. Risk factors include:

1. Age - Mostly affects young adults; older population mostly suffer knee problems as a result of arthritis.
2. Gender - More common in women, as their wider pelvis increases the angle at which knee joint bones meet.
3. Sports - High-impact sports put extra pressure on knees.

What one needs to know about symptoms or signs? The disorder is most commonly identified by a dull ache underneath the kneecap as a person walks down stairs, squats or gets up after sitting for long periods of time. The person may also experience a painful, creaking or grating sensation while bending the knee. Which specialist should be consulted in case of signs and symptoms? Persons with patellofemoral pain syndrome must consult an orthopaedic surgeon or a specialist in sports medicine. What are the screening tests and investigations done to confirm or rule out the disorder? The disorder is diagnosed through the following:

1. Physical exam - The doctor presses on different parts of the knee and moves the leg into various positions to rule out other disorders with similar presentation.
2. Imaging tests - X-rays, computerised tomography (CT) scan and magnetic resonance imaging (MRI) is done to visualise bones and soft tissues in the affected area.
3. Arthroscopy - The doctor inserts a small camera into the knee to understand the condition of the affected area. It is performed in an outpatient setting.

What treatment modalities are available for management of the disorder? Different treatment options include:

1. Medications - Over-the-counter pain relievers like ibuprofen and acetaminophen are prescribed to alleviate pain.
2. Therapy - Different therapeutic options include:
   1. Exercise - Rehabilitation exercises help strengthen muscles like the quadriceps and hamstrings that support the knee and control limb movement, along with muscles around the hips (hip abductors).
   2. Braces - Supportive knee braces and arch supports help protect the joint and improve alignment of the kneecap.
   3. Taping the knee - Taping reduces pain and increases the ability to exercise.
   4. Ice pack - It is helpful to ice the knee after exercise.
   5. Gentle physical activity - Restricting physical activities to sports that are gentle on the knees aids recovery.
3. Surgery and other procedures - In case the above treatments prove unsuccessful, the doctor may suggest:
   1. Arthroscopy - The doctor inserts an arthroscope (a pencil-this device equipped with a camera and light) into the knee through a tiny incision. Surgical instruments are passed through the arthroscope to remove damaged cartilage and fragments.
   2. Realignment - A surgeon operates on the knee to realign the angle of the kneecap and relieve pressure on the cartilage.

What precautions or steps are necessary to stay healthy and happy during the treatment? It may take four to six months till complete recovery, and the patient must limit intense physical sports during the time. However, physiotherapy sessions can greatly improve recovery time. How can the disorder be prevented from happening or recurring? Certain measures can help alleviate pain:

1. Exercise - Keeping the muscles of the hip and leg strong through physiotherapy helps maintain flexibility and knee balance.
2. Maintaining weight - Losing extra weight helps relieve the stress on the knees.
3. Warming up before exercise - It is important to warm up with light activity before starting any intense workout or sports. Also, sudden changes in intensity of any activity should be avoided.
4. Stretching - Stretching exercises improves flexibility.
5. Proper shoes - Wearing fitted shoes that provide adequate support is equally important.

 Sources:"Chondromalacia patella," MayoClinic.com, Mayo Clinic Staff, https://www.mayoclinic.org/diseases-conditions/chondromalacia-patella/basics/definition/con-20025960"Knee pain and other running injuries," NHS.uk, https://www.nhs.uk/Livewell/c25k/Pages/running-injuries.aspx"Patellofemoral Pain," WebMD.com, https://www.webmd.com/a-to-z-guides/patellofemoral-pain-syndrome-topic-overview"Patellofemoral Pain," Patient.co.uk, https://www.patient.co.uk/health/Patellofemoral-Pain.htm"Patellofemoral Pain Syndrome," USCF Medical Center, https://www.ucsfhealth.org/conditions/patellofemoral_pain_syndrome/"Runner's Knee," WebMD.com, https://www.webmd.com/pain-management/knee-pain/runners-knee"Runner's Knee (Patellofemoral Pain)," American Academy of Orthopaedic Surgeons, AAOS, https://orthoinfo.aaos.org/topic.cfm?topic=a00382