Why are knock knees harder to replace, especially in a tall patient?
Dr. Mahajan is Chairman Orthopaedics, Joint Replacement & Chief Robotic Joint Replacement at Max Smart Super Speciality Hospital, Saket.
A tall woman with severe arthritis and knock knees, knees that bend inward toward each other, came to Dr Ramneek Mahajan for a knee replacement.
Why did the patient need surgery?
The patient says she had problems with her knees for a long time, starting with one knee. The earlier advice was to wait, the second knee got worse, and her mobility became very poor.
Dr Mahajan says she had severe osteoarthritis in both knees, the wearing away of the smooth surface inside a joint that leaves it stiff and painful.
Which operation was chosen, and why?
Dr Mahajan says that during the knee replacement, robotic technology, a robotic arm the surgeon uses to guide the cuts, helped the surgeons find their way into the thigh bone and get the right fit for the patient.
What made the operation harder?
Dr Mahajan says that what sets the patient apart from a routine case of arthritis is that she is tall and slightly heavier, and has knock knees. This means she puts a lot of strain on her hip and back when she walks, and straightening such knees causes pressure on the nerves and blood vessels.
How did the patient recover?
Dr Mahajan says that after the operation on the patient's first knee she tried to walk: first with a walker, then with a stick, and within a few minutes without a stick.
The patient says she can now walk, and her pain is about 90 per cent less.
What should a patient with knock knees ask?
This is one woman's story, not a promise: what an operation can do for you depends on your own case.
Ask what straightening your knees means for the nerves and blood vessels, and how the surgeon plans for it.
Ask whether your height and weight change the plan for the operation.
What this case teaches
Knock knees are found in 18.5% of people having a knee replacement, a 2026 review in EFORT Open Reviews reports.
With one method of lining up the new knee, long-term results for knock knees matched bowed knees, the same 2026 review reports.
In 328,314 knee replacements in Japan, a foot-weakening nerve injury followed 0.10%; knock knees scored highest of four warning signs, a 2026 study found.
Injury to the nerves or blood vessels around the knee is rare in knee replacement, the American Academy of Orthopaedic Surgeons says.
