The knee is the largest joint in the body. It is susceptible to injury as it is composed of many parts- bones, cartilage, ligaments and tendons. It is involved in ambulation, and is weight bearing. The bones are comprised of the thigh bone, the femur, the shinbone the tibia and the kneecap, the patella. The ends of the bones are covered with articular cartilage. It is smooth and allows the bones to move against each other without friction. There are wedges of a tough rubbery cartilage called ‘meniscus’ which act as shock absorbers between the femur and tibia. Ligaments connect bone to bone and keep the knee stable by holding the bones together. The collateral ligaments are found at the side of the knee, and are involved in sideways movements. Cruciate ligaments are inside the knee joint and are used for back and forth motions. The tendons connect muscles to bones. They connect the front thigh muscles to the kneecap, and from there to the shin bone.
Diagram of anatomy of the knee
Knee pain can arise from an injury to the ligaments, bursae, tendons, ligaments, cartilage or muscles, or from a condition which affects the joint. Pain may also be felt from conditions affecting the soft tissues, bones or nerves. Knee pain is common in rheumatic diseases, such as rheumatoid arthritis and reactive arthritis, as well as conditions such as lupus and osteoarthritis. Overuse of the knee may result in inflammation of the tendon below the kneecap (Runner’s Knee) and bursitis. Symptoms would include swelling, joint redness and heat, difficulty bearing weight on the affected leg, bruising, clicking noises as the knee moves, weakness, joint instability, tenderness and stiffness. Many of these symptoms would arise from excess fluid in the joint.
Photo of a runner clutching their knee
Injury can occur when an external force bends or twists the knee in a way that it was not designed for. Falls are common causes, as well as sport and accidents. If an impact is severe, many different problems may occur in the knee affecting different parts of its structure. Risk factors for injuring a knee include:
- - High impact sports, such as running or football.
- - Wearing shoes with cleats which can encourage sudden direction change.
- - Overweight.
- - Overuse of the knee and over training.
- - Not sufficient rehabilitation after an injury.
- - Falls or osteoporosis (mainly amongst the elderly).
- - Chondromalacia patella (CMP)- inflammation of the underside of the patella, which is an anatomical problem affecting more women than men.
Osteoarthritis is a condition which occurs when the cartilage degenerates and the bones start to rub against each other. It is common in the knee, with pain increasing with activity. Resting may result in stiffness, and the joint may enlarge as new bone forms where the cartilage has degenerated. Rheumatoid arthritis can affect many joints, including the knee. The knee becomes warm and swollen. Gout is characterised by a rapid onset, with the joint becoming swollen, inflamed and painful with a limited range of movement. It is a result of uric acid crystals building up in the joint. Bursitis occurs when the bursae are inflamed. It can result from arthritis, degenerative joint disease, kneeling, an infection, gout or due to an injury. The knee becomes painful and swollen.
Swollen red knee
There are many conditions which may affect the knee and cause pain. ‘Jumper’s Knee’ involves inflammation of the tendons. The pain is localised, and is worse with activity. It arises typically during jumping sports. Patellofemoral syndrome and chondromalacia patella occur when the kneecap rubs against the outer or inner femur instead of being in the middle of them. The cartilage on the underside of the kneecap breaks down. The joint becomes inflamed and the pain increases upon sitting or activity. Athletes, women and the elderly are more prone to these conditions. Fractures and dislocations should be dealt with immediately by a doctor. Injury to the ligaments can occur when (during sport) quick changes in direction are made. Other structures within the knee may also be affected.
Physiotherapy can help in the management of knee pain, and improve strength and flexibility. Arthritis in the knee may arise as a secondary problem after an injury. Treatment can halt the progress of the problem. A physiotherapist would look at all the knee structures in order to accurately diagnose the problem. They would use specific techniques to decrease the pain and to correct the movement dysfunction. This may involve massage, mobilisation (the knee is passively moved at different rates and number of repetitions), taping and strapping to help the muscles to function properly, and ambulation exercises to encourage walking. Coordination exercises help with balance, conditioning exercises with range of movement and muscle strengthening and stability exercises to work on the core muscles. They may use electrotherapy to encourage muscles and tendons to repair, or laser therapy to reduce swelling and pain. A TENS machine stimulates nerve fibres and blocks pain signals travelling to the brain. Biofeedback uses electrical pads to monitor activity of muscles and posture to help with movement and function. Muscle stretching and strengthening has been shown to have a positive effect at 3 months, which was maintained after one year, in a study with anterior knee pain sufferers1.
Physio using TENS machine on a patient
Osteopaths believe that pain can arise from poor posture and misalignment of body structures. After taking your medical history and details of the problem and symptoms, you would be examined and any relevant tests conducted. Passive and active movements would be observed. Upon diagnosis, treatment would include massage, stretching, repetitive movements and manipulation. The aim is to find the root cause of the problem and to treat that as well as the symptoms.
A chiropractor would also wish to talk to you at length concerning your problem. As part of establishing the cause of the knee pain, other joints would be evaluated as pain may be referred from the back or hips. If theses joints are working incorrectly, stress is put upon the knee joint. In order to reduce pain and inflammation advice would be given concerning avoiding aggravating factors. Support tape may be used, ice to reduce spasm and pain, and soft tissue healing encouraged by laser or ultrasound therapy. Specific manipulation and mobilisation techniques would be used to help to normalise the joint. Deep tissue massage will help to decrease pain, trigger point therapy (concentrating on a problematic area), and cross friction (working across muscle fibres) all aid healing and increased circulation to the area. During rehabilitation, exercises to develop strength, stability and balancing the joint will help to avoid reoccurrence of the problem.
Chiro demonstrating exercises for a patient
Acupuncture has been shown to be effective in reducing pain in arthritis of the knee2. A study revealed a decrease in pain and stiffness and an increase in muscle strength and flexibility in the knee. The belief in Chinese medicine is that health is governed by the flow of ‘qi’, the life force around a network of channels in the body. A blockage can occur as a result of illness or stress. Fine flexible needles are inserted in order to clear the blockage, and the pain and root cause of the problem addressed. Acupuncture stimulates the release of endorphins and enkephalin, which are natural painkilling substances produced by the body, as well as cortisol, which helps to reduce inflammation. It encourages circulation to the area, and helps muscles to relax.
A podiatrist is concerned with injury and ailments affecting the feet and lower limbs. They are able to treat problems relating to the body’s mechanics and movement. Advice concerning rehabilitation and how to strengthen and stretch associated structures will help reduce pain. Orthotics can be prescribed to correct problems associated with gait and movement style, which have shown to be effective in the prevention of ‘Runner’s Overuse’ Injuries3.
- Dr Clark D et al ‘Physiotherapy for Anterior Knee Pain: A Randomised Controlled Trial’. Ann. Rheum. Dis. 2000 Vol 59 700-704.
- Yurtkuran M et al ‘Tens, Electro-acupuncture and Ice Massage: Comparison of Treatment for Osteoarthritis of the Knee’. Am. J Ac. 1999 Vol 27 (3-4) 133-40.
- Eggold, JF ‘Orthotics in the Prevention of Runner’s Overuse Injuries’. The Physician & Sports Medicine 1981 Vol9 (3) 124-131.