Maltracking of the patella

A maltracking patella generally tracks more laterally between the femoral condyles. The cause can be anatomically distant from the knee, from increased functional anteversion at the hip or overpronation at the foot, both of which increase functional valgus at the knee. Anatomical variations at the knee can also increase a valgus knee action. This valgus action tracks the patella laterally. The pain, however, is medial, around the patella.

General findings for faults at the hip, knee and foot

a)      There is diffuse, poorly localized, anterior knee pain

b)      All have functional valgues at the knees on the half-squat test

c)      Patellar apprehension is often positive

d)     The medial patellar facets are tender to palpation

e)      Clarke’s test is painful or inhibited

f)       The running style tends to be a low knee carry, with a windmilling effect of the lower leg such that, when the patient is seen soon after exercise, they may also present with tender capsular ligaments of the knee

g)      Pain whilst sitting with the knees bent. Some athletes also sit on a chair or the floor with their knees close together but their feet out to the side, and the knees in valgus and external rotation

h)      The step down test displays the functional valgus movement at the knees

Fault at the hip

In addition of general, athlete has anatomical or functional anteversion of the femur. Those with anatomical anteversion of the hip stand with their feet together and straight legs, but the patellae squint inwards. Internal rotation of the hip is marked, but external rotation limited. The feet do not overpronate. The external rotators of the hip are weak. Patients with functional anteversion have poor core and pelvic stability and will drop the weight-bearing hip forwards and inwards, or the greater trochanter will protrude further laterally. These mechanisms encourage the knee to move into a functional valgus.

Fault at the knee

a)      In addition of general, patients stand with their knees in valgus

b)      There is tenderness over the tibial collateral ligament on valgus stressing and palpation

c)      The medial plica may be tender to palpation

d)     There may or may not be anatomical overpronated feet, but the patient will overpronate in function as the feet follow the effect of the knees

e)      The posterior tibialis is weak on resisted testing

f)       Bayonet sign might be present

Fault at the feet

In addition of general findings:

Group I: The basic anatomical stance is normal, but the feet are overpronated, with weak posterior tibialis on resisted testing.

Group II: There is limited talar dorsiflexion and therefore, in function, the foot pronates to create an apparent increase in functional range of ankle dorsiflexion. The pronation shifts the knee into valgus.

Group III: Tarsal coalition may prevent the feet from adjusting to rough ground, so the knees must make this adjustment, with valgus or varus movements.

Cause

The angle between the hip joint, quadriceps origin and the mid-point of the patella lying normally between the femoral condyles, and the mid-point of the patella and tibial tubercle, is increased beyond 15 degrees. The patella therefore lies towards the lateral femoral condyle, causing strain on the medial capsular structures plus decreased interchondral pressure between the medial patellar facet and the medial femoral condyle, so disuse o fimbriation occurs over the medial patellar facets. Chondral cartilage requires pressure between adjacent articular surfaces to squeeze synovial fluid into the nutrient canaliculi.

Treatment

General

Capsular and ligamentous pains can be eased with non steroid anti-inflammatory drugs and electrical modalities. A weak posterior tibialis should be rehabilitated and strengthened. Lateral patellar tracking or rotation can be reduced with exercises to strengthen and coordinate vastus medialis obliquus muscle.

Fault at the hip

Treat with strengthening and balancing exercises for the external rotators of the hip. The patient should walk and stand tall at the hip and pelvis, pulling the hips into external rotation by muscle tension. Concentrate on the knee staying over the first and second toes in one-legged half squats and whilst cycling or going up stairs. Weak external hip rotators allow the pelvis to swing into adduction and the knee to follow into valgus. Orthotics may reduce functional pronation and thus reduce the work required from the hip rotators, but perhaps long-term development of strength in the external hip rotators is the priority.

Fault at the knee

a)      Rehabilitatioon exercises are the same as those for hip fault, above; however, if an athlete has too many fat in thighs, weight has to be lost

b)      Running repeats the same movements angles across the knees, whereas “direction change” sports will vary this angle, and thus the tracking of the patella. Hence change of direction sports suit the maltracking knee better than running.

c)      Calm any ligamentous strain with electrotherapeutic modalities, NSAIDs or cortisone injection.

Fault at the feet

Corrective orthotics are required, as well as the corrective exercises for the cause from the hip and knee.

Group I: Posterior tibialis strengthening. The psoas may need strengthening to encourage knee lift during running, allowing the swing phase to complete before foot strike.

Group II: A heel raise may help, as in the standing position it moves the talus and foot towards plantar flexion. There is then a greater range of dorsiflexion available, before anterior impingement of the talus against the tibia occurs. Pronation of the foot to avoid this impingement is thus avoided. A shorter stride patterns should be advocated, and high knee drills prescribed to encourage lift off of the foot at the midstance phase, father than pushing through to toe off, at which stage the limited dorsiflexion of the foot induces a functional pronation. Use of orthotics other than a heel raise may help, but if pronation is the way out of the limited dorsiflexion, they can make the situation worse.

Group III: May have to accept the problem and increment loads more slowly, or consider takin up a non- running sport.

Sports

a)      Change of direction sports cause fewer problems than running because the femur/ patella positions alter, in contrast to being repeatedly maltracked, as in running.

b)      Swimming breaststroke or butterfly can increase valgus stress at the knee.

c)      Hill running can cause problems if knee lift is poor. The swing phase is not completed before foot strike, thus the foot lands in external rotation and pronation.

d)     Running on a camber may produce functional valgus on the higher side.

e)      The knee must be maintained in line over the foot during “step ups”.

f)       Bicycles must have play in the foot, knee mustn’t be locked into one position, and forefoot varus must be corrected at the pedal with a wedge on the shoe or the pedal. Vastus medialis obliquus function is encouraged by training with a raised saddle, and the knees should move in line with the feet, over the pedals.

g)      Some runners who land into the mid-stance phase instead of heel strike will run onto a soft pronating foot and the knee will suffer both overload and tracking problems. 

 

"Concise guide to sports injuries, 2^nd edition",Churchill Livingstone, Malcolm T.F. Read,  foreword by Bryan English