Fit & Proper: When weight affects the joints

In 2014, worldwide obesity had more than doubled since 1980, with over 600 million adults diagnosed as obese and over 1.9 billion diagnosed as overweight, according to a World Health Organisation report. Today, almost five per cent of India’s population is struggling with the epidemic. Besides heart diseases and high blood pressure, knee joint pains are a common issue arising from obesity.

A person’s body weight is focused on the knee joints. The ends of the bones that form knee are covered with a cartilage that is responsible for smooth movement.  When the person is obese, he or she adds more pressure on the cartilage, leading to its early wear. When this condition aggravates, it leads to osteoarthritis. Severe osteoarthritis might require knee replacement surgery.

The surgery involves the replacement of the knee joints with an artificial material. In this procedure, the lower end of the thigh bone, or femur, is replaced with a metal shell and the upper end of the leg bone is replaced with a metal plate and plastic inserted in between. A plastic button may also be added under the kneecap surface. The positioning of the artificial knee is assessed with the manual alignment jigs. These jigs may display an error of about three degrees despite being performed by experienced doctors. Over time, the technology used for the treatment has undergone drastic transformation. A relatively non-invasive technology, Pinless Computer Navigation Assisted Total Knee Replacement procedure, has gained huge popularity among masses.  

This technology is a boon for patients with knee osteoarthritis with severe deformity of legs and ensures complete correction. In the procedure, special sterile probes are touched to different part of the knee during the surgery in order to create a 3D model with the help of an infrared camera.

Its advantages:

• The state-of-the-art surgical technique improves the accuracy of knee replacement surgery from around 80 per cent to up to 99.9 per cent.
• It ensures proper placement of the implant and alignment of the artificial knee.
• It reduces chances of life-threatening complication of fat embolism, as one need not drill a hole in the medullary canal of the thigh bone.
• It reduces complications associated with the older version of computer navigation (with pins).

Computer navigated surgery takes into account each patient’s shape and the size of the knees and allows a surgeon to use what is essentially a mini GPS system to register the exact bio-mechanic anatomy of the leg and knee joint to ensure that each replacement is as accurate as possible.  

In the early days of knee replacement, obese patients were often told to lose weight prior to the operation. It was believed that the morbidity in overweight patients was greater. Studies have shown that the result of knee replacement in obese patients is as good as in people who are not obese. However, in people who are obese, skin healing might be a problem and might need extra attention. Good physical activity and regular walks are recommended after a knee replacement surgery in these patients to help shed a few extra kilos.

Next week: How to take care of your loves ones suffering from Alzheimer’s

Anil Arora, Director, department of orthopaedics & joint replacement surgery, Max Super Speciality Hospital, New Delhi