Question 1

Is every patient a candidate for knee replacement, and is every patient eligible for the robotic technique, or is there a criteria on which you decide?

Dr. Rakesh Mahajan · Accepted Answer

From the patient's perspective, every patient is eligible for robotic knee replacement, and the surgeon can advise that robotics is not needed in certain cases. The clear indications are an old fracture at the distal end of the femur or the proximal end of the tibia causing an angular deformity, or existing hardware that prevents medullary alignment, since conventional alignment passes a rod inside the femur. A valgus knee of more than 7, 10 or 12 degrees is another clear indication, while a small or moderate deformity can be done very well with mechanical alignment.

Question 2

In many disciplines a robotic or minimally invasive procedure sometimes turns into open surgery. Does this happen in knee replacement also?

Dr. Rakesh Mahajan · Accepted Answer

It doesn't, not in robotic knee replacement. Rarely there is a failure of the machine or the tracking system, and the surgeon can then easily shift to the conventional technique, so there is not much of a problem there.

Question 3

The advantages of robotics are precise, minimal cuts, but when a surgeon's hand is also very precise from decades of experience, does a surgeon like that really need robotics?

Dr. Rakesh Mahajan · Accepted Answer

I agree with you. Surgeons of my age and experience still prefer mechanical alignment. But certain things are market-driven, and with time market forces take over from conventional methods; over time the robotic takeover may become much stronger than conventional surgery, as is happening in every field. Initially the cost of robots was quite high, but companies are now coming up with smaller, portable robots and costs are decreasing. I expect AI-generated alignment of the robotic arm to come in the future.

Question 4

In the news we see reports of robotic surgery done remotely. Are orthopaedic surgeries, such as joint replacement, being done remotely?

Dr. Rakesh Mahajan · Accepted Answer

Telesurgery has not been tried in knee replacement or hip replacement, because that software is not usually available. It may be available in the future, but presently it is not there.

Question 5

There is a risk of infection after knee replacement. How do you go about minimising and eliminating the risk of implant infection down the line?

Dr. Rakesh Mahajan · Accepted Answer

If the patient is diabetic, HbA1c is checked before admission and must be in range: patients at 9 and above are not fit for knee replacement because the infection rate goes up significantly, and the target is below 7, or 7.5 at most, with referral to a physician until it is. If the patient has urinary symptoms, a urine routine and culture and sensitivity are done before admission, and the infection is treated before surgery; bacteria in the urine without symptoms do not need treatment. Uncontrolled diabetes is one of the most important correctable risk factors for infection after total knee replacement.

Question 6

One patient had one knee done by robotic replacement and the other by conventional replacement and could not tell which was which. Since robotic surgery means minimal cuts, wouldn't the patient know which knee had more cuts?

Dr. Rakesh Mahajan · Accepted Answer

It is not about the number of cuts. The distal femoral cut and the proximal tibial cut create the flexion and extension gaps, and the cut itself is the same in mechanical and robotic alignment. In mechanical alignment it may need to be made two or three times, or the result may come in one sitting, whereas in robotic alignment one cut is generally good enough to balance the flexion and extension gaps. The patient doesn't know anything about the number of cuts.

Question 7

There are a lot of myths around knee replacement surgery and recovery. How is recovery, how does quality of life improve, and what normalcy in function returns?

Dr. Rakesh Mahajan · Accepted Answer

Recovery is very good and quality of life improves immediately. If admission is today, surgery is the next day and the patient walks by the third day with a walker under a physiotherapist's guidance; by the fourth or fifth day the patient climbs stairs and walks without support, and by the sixth day can go home without support. Outcome depends a lot on the quadriceps muscles: if they are weak the patient takes longer, and if the power is good the patient recovers very fast, so physiotherapy strengthens them with isokinetic exercises.

Question 8

Prevention is the best cure. For people who are not elderly yet, what modern lifestyle factors lead to or accelerate knee degeneration, and what should someone in their 40s avoid and focus on?

Dr. Rakesh Mahajan · Accepted Answer

It depends on your workload, but even if you are very occupied, find time to keep yourself physically active. The two good exercises for the knee are walking, for a minimum of half an hour, and cycling, including static cycling. These strengthen the quadriceps, and strong quadriceps keep the knee much healthier; once the quadriceps become weak, the pain keeps increasing. Knee degeneration is also more common in women because of hormonal changes after the age of 45 to 50: once menopause sets in, the lubrication of the knee weakens, which affects the cartilage. As the cartilage wears, the patient has pain and moves less, the muscles weaken further, and a vicious cycle sets in. What I always advise: keep yourself physically active, eat healthily and do not be overweight. If you are overweight, change your diet towards more protein and fewer carbohydrates, and walk wherever you can instead of using your car.

Question 9

Would relatively high-intensity exercise, like running within a limit, put more pressure on the knees?

Dr. Rakesh Mahajan · Accepted Answer

Once knee arthritis starts, stop jogging and running and just walk. One can climb up to two floors, not beyond, because more will start damaging the knee further. If there is no knee pain or problem, one can do anything.

Question 10

Is joint arthritis one of the main indications that tells doctors or patients it may progress, or are there other factors that lead to it?

Dr. Rakesh Mahajan · Accepted Answer

There are some genetic factors as well, plus metabolic causes. In diabetic and hypothyroid patients, and in rheumatoid patients, the knee is affected much earlier. I have patients who develop bad knees between the ages of 35 and 40 because of these metabolic or autoimmune diseases.

Question 11

How do we ensure efficient knee joint lubrication?

Dr. Rakesh Mahajan · Accepted Answer

By regular knee exercises, giving sufficient time to them, which produces natural lubrication. There is a group of supplements called nutraceuticals which are often tried, but current guidelines do not recommend them, because good trials have not shown a benefit.

Question 12

You named walking and static cycling as the first exercises. Do they count as knee exercises from this perspective?

Dr. Rakesh Mahajan · Accepted Answer

They are the best exercises for the knee. But if you do not have any knee problem, you can run, jog, play tennis or do anything.

Question 13

What are the best drugs or supplements you would recommend for knee lubrication and cartilage?

Dr. Rakesh Mahajan · Accepted Answer

Earlier, the basic options were chondroitin sulfate and glucosamine. Now there are many collagens in use across specialties; in orthopaedics, collagen types 1, 2 and 3 are used, with collagen 2 marketed for the knee and other formulations promoted for cartilage. Collagen 1 and 3 are the main components of tendons, while collagen 2 is mainly found in the cartilage of the knee. However, the major osteoarthritis guidelines do not recommend glucosamine or chondroitin, and there is not yet good evidence that collagen supplements rebuild cartilage; exercise and weight control remain the mainstay.

Question 14

Because of biological factors even people in their 30s may need knee replacement. After replacement and enough physiotherapy, can they return to an active lifestyle such as tennis, swimming or sports?

Dr. Rakesh Mahajan · Accepted Answer

Contact games are not recommended because they cause more wear and tear, and the high wear of the implant components will cause aseptic loosening. Patients can lead a good, healthy life, with walking, cycling, swimming and light uphill activities recommended. Tennis or badminton, which require frequent jumping, are in between, but they are high-activity games which are not recommended, and many studies advise avoiding them.

Question 15

If a patient has a good recovery and follows instructions long term, what is the life of the implant, and can complications bring them back to the surgeon?

Dr. Rakesh Mahajan · Accepted Answer

The latest fifth-generation implants have a long life. With the earlier second-generation implants, which lasted 12 to 15 years, patients did come back. With the latest implants, I have patients more than 15 years out who are doing perfectly well, and registry data show that about 93% of knee replacements are still in place at 15 years and about 90% at 20 years.

Question 16

Have you managed knee replacement situations in pregnant patients, or do you wait until the delivery is done?

Dr. Rakesh Mahajan · Accepted Answer

In pregnancy we give only minimal, first-aid-type treatment. For a lot of pain we can use cold packs, more physiotherapy and cryotherapy, or, exceptionally, a steroid injection. An offloader can also help alleviate the pain until the pregnancy is over. Joint replacement is elective, so the pregnancy is the first priority: we manage with other methods until the pregnancy is over, and then we can proceed.

Live Discussion with Dr. Rakesh Mahajan