Knee pain is one of the most common ailments and can affect patients of any age, particularly the older generations.
The knee joint allows movement between three bones: the femur (thigh bone), the tibia (leg bone) and the patella (kneecap). Two semi-circular pieces of cartilage between the femur and tibia called menisci act as shock absorbers. Four ligaments, two located centrally (cruciate) and two located peripherally (collateral) function to stabilise the joint.
The joint itself sustains significant forces during walking, which increase with running and forceful exercise. These forces increase the likelihood of injuries particularly in athletes or footballers. Injuries to the knee can include fractures, while twisting injuries may damage the menisci or ligaments. This could cause swelling and pain in the knee, which if left untreated could lead to chronic knee pain. Injuries to the menisci and ligaments lead to instability that may present as knee locking or giving way. These injuries could limit one’s ability to walk, run or play sport.
Diagnostic tests such as X-Rays and MRI scans show the extent of damage within the joint. Many injuries will require keyhole surgery, where a tiny camera is placed inside the knee joint and a torn meniscus repaired or trimmed. Torn cruciate ligaments often cannot be repaired; they may be surgically replaced with parts of tendons take from other locations of the lower limb or by artificial ligaments.
In older patients, knee pain is usually due to arthritis, but other conditions such as infection, gout or cancer may also cause pain. Arthritis results from wear and tear, where part or all of the cartilage lining the knee joint can erode away causing the bones rub directly against each other. In most cases of knee arthritis, no apparent cause is identified; this is called primary arthritis. Rarely however, arthritis may result from prior injury or fractures around the knee, or from some underlying inflammatory joint condition such as rheumatoid arthritis.
Occasionally, arthritic knee pain may also be referred to the hip joint. Symptoms of arthritis include pain and swelling that are mainly due to fluid in the knee as well as stiffness and locking. The pain may affect walking distance as well as night-time sleep. Walking up and down stairs may be painful particularly if the front part of the knee joint is affected.
The diagnosis of arthritis can usually be made through the clinical history and physical examination; however, the diagnosis is confirmed with knee X-Rays, which also confirm the extent of disease. Internal knee damage resulting from arthritis such as meniscal tears or subtle fractures can be detected on MRI scans.
Treatment of knee arthritis includes physiotherapy, weight loss, exercise and muscle building or use of an external aid such as a walking stick. The use of steroid injections is controversial with some studies reporting good results in cases of early osteoarthritis while others showed equivocal effects. Other knee infiltrations available include a class of drugs known as “viscosupplements”; these are viscous substances that when injected into the knee joint act as buffers and are thought to regenerate the cartilage lining. Results obtained with these injections have been varied. Recently the use of PRP (platelet rich plasma) injections has increased in popularity. In this technique, which is readily available in our service, a sample of the patient’s own blood is centrifuged, and the platelet-rich part of the sample is then injected into the knee. The PRP is thought to stimulate the body to grow new healthy cartilage cells and promote healing.
In cases where non-operative treatment fails, surgery may be indicated. This may include a washout of the knee through keyhole surgery, which is normally effective in patients with early arthritis and for those with mechanical symptoms such as locking and giving way in addition to the pain. Total knee replacement remains the most reliable surgical way of treating knee severe knee arthritis. This is a major operation with a number of risks and potential complications. However scientific studies repeatedly reported significant improvement in the quality of life in patients undertaking this procedure with a more than 85% satisfaction rate. Recent studies have shown improvements in the lifespan of these artificial joints; these are now being recommended even for younger patients with debilitating knee arthritis.
Mr Alistair Melvyn Pace
MD (Melit) MRCS (Eng) MRCS (Edinburgh) FRCS (Tr & Orth) MSc (UK) Dipl (Orthopaedics) CCT (UK)
Consultant Orthopaedic & Trauma Surgeon
Senior Lecturer University of Malta
DaVinci Hospital, Birkirkara