High flex knee for osteoarthritis of knee – A boon to the old age

Dr Ramesh Vadapalli, MS (Orthopaedics), Fellow in Arthroplasty

Movement is life and life is movement. It’s everybody wish to keep pace with life, but everyone is not that fortunate. As you grow older, joints get worn out in some people due to many reasons and we call this wearing out of joints as osteoarthritis.  It is also called degenerative joint disease where in the smooth cushion layer (cartilage) which is 3-5 mm thick on the ends of bones forming the joint wears away leading to damage of the joint.

Osteoarthritis due to old age is known as primary osteoarthritis. It is called secondary arthritis if the joint is damaged by other cause like joint infections (bacterial), inflammatory arthritis (Rheumatoid arthritis, Gout), fractures, tumors, or neurological conditions. Degenerative (age related) arthritis is the most common type.

Primary osteoarthritis can involve any joint in the body but it commonly does involve hip and knee. Osteoarthritis of knee is predominantly seen. It predominantly affects people in their sixties or seventies. Women are more commonly affected (61%) than men.  Women bones tend to become weaker in old age due to hormonal imbalances (menopause).

A number of studies have shown that there is a greater prevalence of the disease between siblings and especially identical twins indicating a hereditary basis. Up to 60% of cases are thought to result from genetic factors.

Being overweight (Obesity), smoking, alcohol abuse, thyroid related problems, diabetes, humid and cold weather all aggravate this condition.

The foremost symptom experienced is pain. It can be mild to start with, but become severe as the disease progresses and later swelling of joint with fluid collection, cracking noise (crepitus) and stiffness follows. In some of the individuals as the disease progresses, it causes severe pain, leading to severe restriction of joint movement, deformity (bow legs) and instability. This causes profound disability where they are unable to sit cross legged or squat on the floor.
A simple x-ray will confirm the diagnosis and severity of the disease can be assessed. In the initial stages, we can delay the progression of joint damage by life style modifications like reducing the weight, wearing soft cushioned foot wear; exercises which strengthen the muscles of thigh and leg, aerobic exercises, brisk walking, cycling and swimming. Of all, swimming is the best exercise in advanced stage.

Oral medications and knee braces will help initially, but not in advanced stage. Be aware that prolonged intake of pain killers will have a detrimental effect on the stomach, kidneys and heart. Corticosteroids either orally or as injections into the joint should be  strictly avoided  except in inflammatory arthritis(rheumatoid arthritis).Cleaning of the joint by arthroscopy(key hole surgery) once thought as treatment of choice   can only give relief for only a small period of time. Recently cartilage supplementing injections are available, these are given into the joint and these give reasonable relief from pain in a few cases.

What is a Total knee replacement?
Total knee replacement (TKR) also known as Total knee arthroplasty (TKA) is the best available permanent option for severe osteoarthritis.

As the name suggests we do not replace the entire bone, we just resurface the joint.  This operation involves the removal of just 8 mm-10 mm of damaged, worn out surfaces of the thigh bone (femur), and leg bone (tibia) bones of the knee joint, as well as the kneecap (patella).  The bone ends are recapped with metal prostheses and plastic liners which are strong and durable and give stable, smooth movement with very little friction.

What is a High flex knee?

Every normal person should be able to bend his knee from 0 to 155 degrees (calf touching the back of thigh) conventional standard knee replacements could bend the knee up to approximately 110°and only very few patients can bend beyond 120°. But many individuals who are involved in deep knee bending activities are scared of further limitations in their daily activities with these old designs.

A new total knee replacement implant called as a high flex knee is designed to do deep knee bending activities. The high flex knee replacement is the first knee specifically designed to safely accommodate flexibility of up to 155 degrees.

Many activities of daily living such as climbing stairs (75-140 degrees), sitting in a chair (90-130 degrees), gardening, golfing or activities such as kneeling for prayer especially muslims  are possible with this high flex knee. High flex knee is a boon to those who prefer to sit cross-legged and squat on floor for religious and social purposes.

This prosthesis is implanted by special instrumentation and the operation is minimally invasive and does not damage the tissues. Hence recovery is faster after the operation. Patients are made to walk on the next day after surgery and discharged from the hospital with in 5 days. Patients will be back to their daily activities in a month.
It is very much affordable and less expensive unlike standard prostheses. The high flex knee may be an option for many patients to help them achieve the goal of bending till 155 degrees. A well analyzed, well planned and executed high flex total knee replacement results in good functional outcome and longevity of prostheses and greater patient satisfaction. Research has shown that total knee replacement provides substantial improvement in patients’ pain, functional status, and overall health-related quality of life in about 9 out of 10 patients. Movement is the best medicine for old age, so they do not suffer in silence and keep pace with life by giving fresh life to your joints.

Queries are most welcome at ramesh.c.vadapalli@gmail.com or can be contacted at 592 226-4279.

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