When ankylosing spondylitis has fused both hips and both knees, which joints are replaced first, and why?
Dr. Mahajan is Chairman Orthopaedics, Joint Replacement & Chief Robotic Joint Replacement at Max Smart Super Speciality Hospital, Saket.
A man in his forties had lived with ankylosing spondylitis, a long-term arthritis that stiffens the spine and joints, for seventeen or eighteen years, and was close to bedridden when Dr Ramneek Mahajan treated him.
What had the condition taken from the patient's daily life?
A family member says it began one day with severe pain and stiffness in the patient's neck, which the family first put down to long hours at a laptop.
The patient says the pain eased after he walked for five or ten minutes, and at first he thought it came from eating late at night. Then it got worse: back pain every morning when he woke, and then, slowly, his shoulders, hips, knees and ankles were affected.
The same family member says the patient became close to bedridden, and could not even lift his daughter.
What did Dr Mahajan find?
Dr Mahajan says that when the patient came to him, both hips and both knees had ankylosed, and the patient was bent into a curled-up position as he tried to move around and manage his daily tasks.
A joint that has ankylosed has stiffened and fused, so it barely moves.
Why were the hips replaced first?
Dr Mahajan says all four joints of the legs needed surgery: both hips and both knees had to be replaced. The operations were done in two stages over six weeks, with both hips first, so the patient could start to lie straight and, once he could stand, begin training his back.
What was done, and in what order?
The patient says both hips were replaced at the same time, and that it took him about two to three months to get back to normal.
Dr Mahajan says that when the patient came back for the second stage, both knees were replaced together with a robot's help, the surgeon using a robotic arm to guide the cuts.
How was the patient three days after the knee operations?
Dr Mahajan says that three days after the knee operations, the patient could stand straight, get out of bed and try a few steps.
What should a patient with ankylosing spondylitis in several joints ask?
This is one man's story, not a promise: what an operation can do for you depends on your own case.
Ask which joints should be replaced first, and why in that order.
Ask whether both hips, or both knees, can be replaced in the same operation.
If back pain eases after a short walk and comes back each morning, ask whether an arthritis such as ankylosing spondylitis could be the cause.
What this case teaches
Ankylosing spondylitis is a long-term condition that inflames the spine and other areas; in some people it damages hips or knees, the NHS says.
People with ankylosing spondylitis having a hip replacement were about 39 years old on average, a 2025 review of 19 studies found.
In four observational studies, hip movement improved after replacement in ankylosing spondylitis, that 2025 review reports, calling for more research.
