The knee is a joint rich in anatomical structures; therefore, disease processes affecting it can be many and varied. In this article, we will focus on anterior knee pain, its causes, and treatments to relieve it.
Anterior knee pain: what it is
Anterior knee pain is an algic syndrome, often caused byaltered motion of the patella during flexion-extension (the natural “bending” of the knee).
In the daily movements that the knee makes, the patella slides within a natural anatomical track, the femoral trochlea.
If this sliding is not well aligned in the center, the patella is likely to cause pain.
Because of the normal anatomical characteristics of the lower limb, this overload usually occurs on the outer side of the knee; but there are also internal hyperpressures that can cause an antero medial pain, similar to what occurs in meniscal tears.
Anterior patella pain: who it affects
This condition is more common in adolescent girls, particularly among those who have stopped exercising to engage more in study or work activities. In fact, a toned and balanced musculature tends to compensate for anatomical defects such as patellar strabismus or an external patellar prevalence.
Another category particularly afflicted by anterior patella pain is those who overload this joint such as, for example, runners ( Runner’s knee).
All these conditions lead to asymmetric wear of the patellar facet joint also called patellar chondromalacia.
The causes of anterior knee pain
The causes of anterior knee pain, as mentioned earlier, are many but all related to misalignment of the patella during its movement during flexion.
This misalignment may be medial (internal) or lateral (external).
It is possible to identify conditions of hyperpressure (and pain) on the inside of the knee often associated with altered bony rotation of the femur and tibia: this leads to the characteristic picture of patellar strabismus.
Patellar strabismus is so defined because, looking frontally at the patient in an upright position, the kneecaps tend to look inward at the knees.
The most common cause found, however, is a lateral (external) hyperpressure of the patella against the trochlea (the “rail” within which the patella slides) . Women, having an anatomically wider pelvis than men, have a more oblique quadriceps force vector (angle greater than 15°). This oblique vector, during the knee flexion-extension movement, will tend to push the patella toward the outer portion of the knee. This thrust causes wear and tear of the outer cartilage of the patella and subsequent antero-external knee pain.
Additional anatomic conditions that promote this external hyperpressure are:
- A slight valgus knee;
- Less development of the inner portion of the quadriceps muscle (vastus medialis oblique);
- A deficit of the medial patellofemoral ligaments;
- valgus (overpronated) flat feet.
How does it manifest itself?
The clinical manifestation of anterior patella pain can be extremely varied.
It can present with simple discomfort at the end of sports activity, to sudden severe stabbing pain that limits the performance of simple daily activities.
The pain may affect both knees (in this is a typical case of patellar pathology) or even only one knee, despite, the anatomical prerequisites are present in both knees; why this dysfunctional pain occurs only on one side remains, to date, partially unknown.
Frequently, pain occurs after maintaining a sitting position for a long time or classically while descending stairs.
Just as the intensity of pain varies, its location may also be different.
Although the pain is, in most cases, anterior, it can also occur toward the inner or outer part of the knee, as well as posteriorly, when the contracture of the knee flexor muscles becomes more pronounced.
In severe cases, we may even have pseudo-joint locks: the patient will report feeling sudden pain resulting in an inability to move the knee.
These different climatic presentations may misdirect toward meniscal pathology.
Long-term and short-term disorders
Any pressure alteration of the inner or outer side of the patella leads to progressive wear and tear of the cartilage and, therefore, in the long term,patellofemoral arthrosis may develop. But more than in the long term, patellofemoral pathology leads to problems in the short term, limiting the ability to perform sports activities or, even, normal daily actions.
What tests should be performed?
Anterior patellar pain is not easy to recognize as it can have different manifestations and localizations.
A careful analysis of the patient’s medical history, as well as an objective examination of the patient, are essential to bring out this problem, which remains, however, the most frequent knee pathology among adolescents (especially females).
The first examination to be performed is an X-ray of the knees, which, however, often shows nothing abnormal.
The second examination is MRI: in a variety of cases, it, too, shows no problem except in frankly unstable conditions.
The patellofemoral changes, in fact, occur during dynamic knee motion: neither X-rays nor MRI can show us the altered tracking of the patella during flexion-extension, since they are examinations performed with the knee “stationary.”
It will, then, be dynamic examinations that will confirm the clinical diagnostic hypotheses:
- X-rays or C.T. in axial for patella at different degrees of flexion.
- T.C. study of the torsional axes of the lower limbs
Treatments for anterior knee pain
The vast majority of patellar syndromes will benefit greatly from rehabilitation and the use of orthotics that can correct minor knee defects.
In patients who show the onset of symptoms during intense sports activity, the use of infiltrations with visco supplementary purposes (hyaluronic acid) may be of considerable benefit.
Muscle strengthening of the quadriceps (in particular, of its internal component, the vastus medialis) combined with relaxation therapies(stretching) of the hamstring flexor muscles and posture correction, lead, most patients, to have a significant improvement in symptoms.
For this reason, the use of taping, dedicated orthotics or knee pads will be of great help.
Unfortunately, it will be difficult to achieve a complete disappearance of the symptoms, but their impact on daily life can be greatly limited by relegating them to mere occasional complaints.
Surgical treatment is reserved for that small percentage, about 10%, of those patients who fail to achieve sufficient benefit.
Anterior knee pain: surgical interventions
Just as the causes of patellar syndrome may be varied, the surgical treatments will be equally different.
If the hyperpressure is medial and is due to an alteration of the torsional axes of the femur and tibia, corrective derotative osteotomy will have to be considered: however, this is a fairly rare treatment.
More frequently, one is faced with external hyperpressure: in this case, one must surgically decrease the thrust that the quadriceps force vector has outward or increase the thrust inward.
These surgical treatments have a progression of intensity depending on the severity of the problem:
- Mild cases may be treated with ligament or muscle correction such as medial patellofemoral ligament reconstruction or a vastus medialis oblique plastic;
- In more severe cases, surgical gestures on the bony portions such as anterior tibial tuberosity transposition or trochleo-plasty will also have to be performed.
In association with these surgeries, arthroscopy of the knee is frequently performed to assess the cartilaginous status of the facet joint and possibly perform ancillary arthroscopic gestures (microfractures, shaving, synovial fold removal, etc…).
Postoperative period
Most of these surgeries will involve an initial month of using crutches and, the following months, intense functional rehabilitation.
Changing the strength axis of the quadriceps (the most powerful human muscle) does, in fact, require lengthy and demanding gait and running reeducation.
Do you have an anterior knee pain problem and would like to learn more about possible treatments? Please feel free to contact me.
