Anterior knee pain is a very common symptom in many musculoskeletal rehab or family practices.  In this article, we are going to look at the two most common conditions associated with anterior knee pain, Patellofemoral Pain (PFP) and Patellar Tendinopathy (PT) and address the differences in their respective symptoms and treatment options. 

The following chart shows a comparison of the clinical features of PFP vs PT.


Signs

Patellofemoral Pain

Patellar Tendinopathy

Onset

Running, steps/stairs, hills, any weight-bearing movement activities involving knee flexion

Activities involving jumping and/or changing direction

Pain

Non-specific, vague, may be medial, lateral or infrapatellar aggravated by activities that load PF joint

Inferior pole of the patella, aggravated by energy storage loads such as jumping

Tenderness

Usually medial or lateral facets of the patella but may be in infrapatellar region, may have no pain to patella due to pain located under patella

Localised to inferior pole of the patella

Swelling

May have small effusion, swelling, suprapatellar or infrapatellar

Tendon may be increased in thickness; no joint effusion.

Clicks/clunks

Occasional

No

Crepitus

Occasionally under patella

No

Giving way

Rarely, due to quad weakness/inhibition or subluxation

Rarely due to quad weakness

Knee range of motion

May be decreased in severe cases, usually normal

Normal

Quad contraction in extension

Can be painful, but often normal

Often painful

PFJ movement

May be restricted in any motion, commonly restricted in medial glide due to tight lateral structures

Normal

Functional testing

Squats, stairs may aggravate.  PFJ taping should decrease pain.

Decline squats aggravates pain, PFJ taping has less effect. 

* Brukner & Kahn, Clinical Sports Medicine, 5th Edition. 

Patellofemoral pain is the preferred term used to describe pain in and around the patella in the absence of other pathologies (also called patellofemoral pain syndrome, anterior knee pain or chondromalacia patellae).  There are many anatomical structures that are present in the anterior knee.  Please see the diagram below. 


 

Pain is likely to be initiated as a result of unusual loads place on the patellofemoral joint (PFJ).  Two types of factors can influence the loads; extrinsic and intrinsic factors.   Extrinsic loads come from those that are created as the body makes contact with the ground (ground reactive forces), and are modified based on mass, speed, surfaces, footwear, number and frequency of loading cycles.  Intrinsic factors can affect both the magnitude and distribution of the loads at the patellofemoral joint and can be either local or remote.  Local factors include the shape of the patella, soft tissue tension around the patella and the neurovascular control of the surrounding muscles.  More remote factors affecting how the patellofemoral joint is distributing load include an increased hip/femoral internal rotation, increased hip adduction, increased knee valgus/external tibial rotation, poor trunk and pelvic control, pronated feet and loss of sagittal plane motions. 

Treatment of PFP should include an integrated approach of exercise, taping, manual therapy, foot orthoses or bracing based on the patient’s presentation and to target the underlying factors affecting the unusual load on the patellofemoral joint.  Length of treatment will vary also dependent on the factors involved. 

Patellar tendinopathy refers to pain and loss of function at the patellar tendon.  Another term used to describe this condition is Jumper’s Knee as the result of its common diagnosis in athletes in jumping sports (basketball, volleyball, high and triple jumps).  This is also a common condition in athletes involved in directional change (eg. soccer, football) and those where there are large storage of energy loads on their tendon (eg. running downhill).  There is often a loss in muscle strength in the lower limb (calves, quads, or gluteal muscles) that results in dysfunction of the lower body kinetic chain, especially in its ability to perform a spring like motion or jump.  One key clinical feature of patellar tendinopathy is localized pain at the inferior pole of the patella (the attachment of the patellar tendon to the patella). 

Treatment of PT will be dependent on whether or not the severity of the pain removes the athlete from competition.  If the athlete is able to still perform at an adequate level (not removed from play), the treatment will involve methods to reduce pain, increase strength to affected muscles, correct biomechanical factors and treat the soft tissue structures (not tendon).  No high load training should be provided here as the player will endure enough during training and competition sessions.  When the athlete is out of competition, all of the above, plus increased strengthening, power, energy storage and release exercises need to be incorporated into the rehab program. More invasive therapies like injections (plasma rich protein or corticosteroids) can also be considered but the athlete may require more time off from training/competition.  Because severities in PT can vary, treatment time will also vary and may need upwards of 6 months to fully rehabilitate. 

If you or someone you know is experiencing anterior knee pain, book an appointment today at MMD Chiropractic Health Centre to have your condition assessed and guide you through the appropriate treatment and exercise regime.