In fact, the causes of external knee pain include: knee arthrosis, injuries to the lateral collateral ligament, injuries to the lateral meniscus, rheumatoid arthritis, ilio-tibial band syndrome and bruises to the medial knee .
The Knee: a brief reminder of Anatomy
The knee is the important synovial joint of the human body, located between the femur (superiorly), tibia (inferiorly) and patella (anteriorly).
Its anatomy is quite complex and includes:
- The articular cartilage, which covers the lower surface of the femur, the inner side of the patella and the center of the upper surface of the tibia, protecting all these bones from mutual friction;
- The synovial membrane, which covers the joint from the inside and produces the synovial fluid, a fluid with a lubricating action for all the internal structures of the knee;
- The collateral ligaments, the cruciate ligaments and the patellar tendon, which, all together, guarantee the stability of the joint and the correct alignment between the femur and the tibia;
- The synovial bags, which are small sacs of synovial membrane, filled with a lubricating fluid very similar to synovial fluid;
- The internal meniscus (or medial meniscus) and the external meniscus (or lateral meniscus), which are pads of cartilage with a cushioning and anti-friction function, located on the sides of the upper surface of the tibia.
Thanks to its strategic position and its particular anatomy, the knee plays a fundamental role in supporting the weight of the body and in allowing the extension and flexion movements of the leg, during a walk, a run, a jump, etc.
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In light of this, the most correct definition of external knee pain is lateral knee pain or lateral knee pain.
In any case, even if it is jargon, the expression "pain in the external knee" is the one that best describes the pain to which it refers and which is more easily interpreted by the common reader.
The sagittal plane is the antero-posterior axis that symmetrically separates the human body into two parts, giving rise to a right half and a left half.
Epidemiology. Who suffers most from External Knee Pain?
External knee pain is a common symptom, which can affect people of all ages, but it mainly affects:
- Those who play sports where changes of direction during running, jumps, leaps etc. are expected. (therefore football, rugby, basketball etc.);
- Seniors.
Knee osteoarthritis
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Also known as gonarthrosis, knee osteoarthritis is chronic inflammation of the knee, which results from the degeneration of the articular cartilage present on the femur and / or tibia.
Knee osteoarthritis is, unfortunately, an irreversible and progressive condition; it produces, in fact, injuries to the articular cartilages of the knee that are impossible to recover and with a tendency to worsen over time.
Various factors favor the onset of knee osteoarthritis, including: family predisposition to the aforementioned problem, old age, obesity and a past history of knee injuries (in particular to the menisci and anterior cruciate ligament) .
Knee osteoarthritis causes pain in the external knee when its degenerative action mainly affects the lateral portion of the articular cartilage of the knee.
Injuries to the Lateral Collateral Ligament
The lateral collateral ligament, or external collateral ligament, is the knee ligament located on the external side of the joint, originating on the so-called lateral epicondyle of the femur and ending on the so-called head of the fibula.
Injuries to the lateral collateral ligament consist of strains or, at worst, tears of the connective-fibrous tissue constituting the ligament in question.
Usually, strains and tears of the lateral collateral ligament are the result of a knee sprain, following a sudden and abrupt trauma (bad fall, abnormal torsion, etc.).
External knee pain due to an injury of the lateral collateral ligament localizes in the anatomical segment through which the aforementioned ligament passes.
In medicine, the term "sprain" indicates an injury to the "musculoskeletal system, which is characterized by a" temporary alteration of the internal anatomical relationships of a "joint and the consequent damage, more or less deep, to one or more components articular.
Injuries to the lateral meniscus
The lateral meniscus, or external meniscus, is the layer of fibrous cartilage, with a circular shape, which takes place on the lateral portion of the upper surface of the tibia and which mainly serves to absorb shocks to the joint.
Lateral meniscus injuries consist of injuries, tears and splits of the fibrous cartilage layer.
In most cases, injuries to the lateral meniscus are the result of a knee sprain following an abrupt and sudden traumatic event; more rarely, they result from repeated improper stresses on the joint, which, in the long run, are harmful to the lateral meniscus.
External knee pain due to a lateral meniscus injury is located just below and outside the patella.
Rheumatoid arthritis
Rheumatoid arthritis is a chronic inflammatory disease of the synovial joints, which has as its main target the synovial membrane and which, over time, determines the alteration of the joint capsule, ligaments and articular cartilage.
Rheumatoid arthritis is a medical condition that originates from a malfunction of the immune system, which is the reason for its inclusion in the list of autoimmune diseases.
The exact cause of rheumatoid arthritis is uncertain; it is a fact, however, that factors such as "belonging to the female sex, over 40 years of age, cigarette smoking and" having come into contact with some pathogens such as "contribute to the onset of the disease in question. herpes virus or Epstein Barr virus.
Ileo-Tibial Band Syndrome
Also known as "runner's knee", ilio-tibial band syndrome is the condition that arises from the inflammation of the band of fibrous tissue located along the outer thigh and which runs substantially from the hip (iliac crest) to the portion just below the knee (lateral condyle of the tibia).
The ilio-tibial band syndrome is a functional overload disease, that is, it is the result of the continuous repetition of a movement that improperly stresses the band of fibrous tissue described above (which is then the ilio-tibial band).
Knee bruises in the lateral seat
Lateral knee contusions are injuries of the external portion of the knee that do not compromise the integrity of the joint structures, but which are still responsible for pain.
Typically, the origin of external knee bruises are involuntary falls or blows that directly affect the external side of the joint.
Pain in the external knee following contusion is, in most cases, a condition of mild clinical significance.
;Complications
If the cause is a clinically relevant condition such as knee osteoarthritis or if the treatment of the triggering cause is inappropriate, external knee pain can become a chronic symptom, which afflicts the patient even during the performance of the most trivial daily activities (eg : climbing stairs or entering or exiting the car).
When to see a doctor?
External knee pain is a symptom that should concern and prompt the affected person to see a doctor when:
- It has been going on for several days;
- Despite the rest and the application of ice, it persists and shows no signs of improving;
- It is the result of a knee sprain;
- It is associated with several other symptoms (e.g. joint stiffness, swelling, reduced joint mobility, etc.).
Who to contact in case of External Knee Pain?
External knee pain and its causes are a matter for the orthopedic doctor, ie the doctor specialized in the diagnosis, treatment and prevention of pathologies that can affect the musculoskeletal system.
), research aimed at establishing the reasons for a worrying external knee pain begins with an "investigation into the associated symptoms and with an accurate physical examination, during which the diagnostic doctor performs specific manual maneuvers (eg: anterior drawer test, Apley test, etc.); the investigations, therefore, continue with a "thorough medical history and end, in most cases, with diagnostic imaging, to be precise with an MRI of the knee. and anti-inflammatory, which many people underestimate.
As a rule, in the presence of external knee pain, doctors recommend applying ice 4-5 times a day, for at least 15-20 minutes per pack;
Thanks to their anti-inflammatory power, NSAIDs relieve the painful sensation;
The use of an elastic compression band serves to mitigate any swelling and a possible sense of instability at the knee level;
Keeping the lower limb elevated reduces the blood supply to the knee; less blood flow to a painful knee relieves pain and helps resolve any swelling.
What to do if Conservative Therapy fails?
If external knee pain persists in spite of the above conservative therapy, the doctor will suggest more invasive treatments, mildly or significantly (depending on the circumstance), including:
- Localized injection of corticosteroids.
Corticosteroids are very effective anti-inflammatory drugs, which however pay for their therapeutic power with various side effects, some of which are also very unpleasant.
In the presence of internal knee pain, corticosteroids are used when traditional anti-inflammatory and analgesic methods (ice and NSAIDs) have proved ineffective; - The use of a knee brace.
The brace serves to give stability to the joint.
Its use is necessary when, in spite of the rest and compression of the joint, the instability and swelling of the knee persist; - Physiotherapy.
Fundamental for when external knee pain and associated symptoms are not affected by rest, physiotherapy includes proprioceptive exercises and strengthening and stretching exercises for all the muscles of the suffering lower limb; in particular, the importance of strengthening the muscles should be noted. of the anterior compartment of the thigh (quadriceps femoris). - The infiltration of hyaluronic acid.
Hyaluronic acid is a dense fluid, superimposable, also in terms of composition, to the synovial fluid, ie the liquid that serves to lubricate joints such as the knee, hip, etc. and to protect the cartilages.
From what emerges from numerous scientific studies, the infiltrations of hyaluronic acid in a painful knee would have a pain-relieving effect, would favor the formation of chondrocytes (the cells of the articular cartilage) and would improve joint mobility.
It should be noted that, generally, the effect of a single hyaluronic acid infiltration lasts approximately 6 months. - Transplantation of mesenchymal stem cells.
Isolated from body fat belonging to the same patient (hence the "use of the term" transplant), mesenchymal stem cells have been shown to have regenerative properties against worn joint cartilage.
Mesenchymal stem cell transplantation is an innovative technique of regenerative medicine, which at the moment seems to guarantee comforting results. - Drainage of excess fluid (therapeutic arthrocentesis).
It consists in introducing a special needle inside the suffering knee (to be precise where it locates the swelling) and aspirating.
Often, upon aspiration, the treating physician accompanies the injection of an anti-inflammatory drug belonging to the category of corticosteroids and / or the injection of a hyaluronic acid. - The surgery.
It is the most invasive solution ever, even if - it is important to point out - today the operating techniques are much less bloody than in the past.
Surgery becomes the only way forward, when not only conservative treatments, but also those just mentioned (corticosteroids, knee braces, etc.) have proved ineffective.
How the Cause of Outer Knee Pain Affects Therapy
In the therapeutic management of external knee pain, the cause of the pain is important because:
- It affects the duration of conservative therapy.
- It affects the likelihood of success of conservative therapy.
- It is the "element on which the planning of a possible physiotherapy" is based.
Similarly to the previous case, it is the element on which the planning of a possible surgical intervention is based.
