Disadvantages of Knee Replacement Surgery: An Honest Guide

Knee replacement is one of the most successful operations in modern medicine, but it is still major surgery and it is not right for everyone. Being told about the downsides before you decide is not discouragement — it is how you make a choice you will still be happy with in ten years' time. Here is an honest summary of the disadvantages Dr Oosthuizen discusses with patients in Johannesburg every week.

Recovery takes longer than most people expect. A total knee replacement typically means one to three nights in hospital, crutches or a walker for two to four weeks, and structured physiotherapy for three months. Full comfort and confidence on stairs, in the car and on uneven ground often takes six to twelve months. A partial knee replacement is considerably quicker — many patients walk unaided within two weeks — but it is still weeks, not days.

Some pain and stiffness can persist. Around one in five people with a total knee replacement report ongoing discomfort or a sense that the knee never feels entirely their own. Kneeling is uncomfortable or impossible for many, and some patients notice clicking, warmth or numbness on the outer side of the scar. These are common, usually manageable, and much less frequent after partial replacement because the ligaments and healthy cartilage are left in place.

The joint is not a natural knee. A replaced knee is a mechanical bearing. Bending range is usually good but rarely unlimited, deep squatting and sitting cross-legged may stay difficult, and high-impact sport such as running, squash or contact sport is discouraged because it accelerates wear. Walking, cycling, swimming, golf, hiking and doubles tennis are all encouraged and generally feel excellent.

Implants do not last forever. Modern implants have 10-year survival above 90%, but younger and more active patients are statistically more likely to need a revision within their lifetime. Revision surgery is a bigger operation with a longer recovery than the original — which is one reason preserving bone and ligament with a partial replacement, where suitable, matters so much.

There are real surgical risks. Infection, blood clots in the leg or lung, bleeding, nerve or blood vessel injury, stiffness needing manipulation under anaesthetic, fracture around the implant and anaesthetic complications are all possible. Each is uncommon — most sit well under 2% — but the combined risk is not zero, and it rises with diabetes, obesity, smoking and heart or lung disease.

Cost and time away from life are genuine drawbacks. Even with medical aid cover there are usually co-payments for the prosthesis, hospital, anaesthetist and physiotherapy, and manual workers may need six to twelve weeks off. These practical costs deserve as much planning as the medical side.

For some people, waiting is the better decision. If your arthritis is mild on X-ray, if your pain is controlled with weight management, activity modification, physiotherapy or injections, or if you are still able to sleep and walk reasonably, surgery can safely be delayed. The strongest reasons to proceed are night pain, pain at rest, and a life that has shrunk around the knee.

The most useful step is finding out which operation you actually need. Many patients told they need a full knee replacement are in fact candidates for a partial knee replacement — a smaller operation with a faster recovery and a more natural-feeling knee. Dr Oosthuizen uses the KOGS grading system, which he developed, to assess this objectively from your X-rays and examination rather than by preference alone.