A high tibial osteotomy (HTO) realigns your leg instead of replacing the joint.
The surgeon cuts the top of the shinbone, changes its angle, and fixes it with a plate. That shifts your weight off the worn inner side of the knee and onto the healthier outer side.
It suits a fairly narrow group: YOUNGER, active people, usually under about 60, with bow legs and arthritis on the inner side of the knee only. You keep your own knee, and many people go back to sport and heavy work that a knee replacement would rule out.
The price is a slower start.
The bone has to heal like a fracture, so expect crutches for several weeks and a return to full activity at around 3 to 6 months. Many people still need a knee replacement one day. The osteotomy buys time.
Who it suits
- Pain on the inner side of the knee only, with arthritis confirmed on X-ray and the outer side still in good shape
- Bow legs: the knee is angled so your weight runs down the inside of the joint. A full-length standing X-ray shows how much
- Younger and active, usually under about 60. Some older people who are very active also do well, so age alone doesn’t decide it
- A healthy weight helps the result last
- A knee that moves well: it straightens fully and bends to at least 90 degrees
- No pain behind the kneecap
- Not a good fit for rheumatoid arthritis, arthritis across the whole knee, or very advanced wear on the inner side
The American Academy of Orthopaedic Surgeons has a clear guide to who is a candidate for knee osteotomy.
Osteotomy vs partial knee replacement
Both treat arthritis on one side of the knee, so many people are offered a choice. Neither is better for everyone. See partial knee replacement for the other side of the decision.
- What happens to your joint: an osteotomy keeps all of your own knee. A partial replaces the worn surface with metal and plastic
- Early recovery: usually quicker after a partial, because there is no cut bone that has to knit. After an osteotomy, weight on the leg is often limited for the first weeks
- Impact activity: more people get back to running, jumping and heavy manual work after an osteotomy. High-impact sport is often discouraged after a partial
- Age: osteotomy tends to be offered to younger, more active people. A partial more often suits people in their 60s and beyond
- How long it lasts: at 10 years, roughly 2 in 3 to 9 in 10 osteotomies are still going without a knee replacement, depending on the study. The benefit often fades after about a decade
- What comes next: if the knee wears later, a total knee replacement is still possible after an osteotomy
An osteotomy doesn’t fix the worn cartilage. It moves your weight off it.
Recovery, roughly
Protocols vary a lot between surgeons, especially on how much weight you can put through the leg early. Your surgeon’s protocol comes first. Use theirs.
- Days 0 to 2: usually 1 to 2 days in hospital. Walking with crutches, ankle pumps and thigh squeezes straight away
- Weeks 0 to 6: crutches, often with only part of your weight on the leg. Some surgeons allow full weight early, others keep it light for 6 weeks or more. See weight bearing after surgery for what each instruction means. Getting the knee fully straight and bending comes first
- Around 6 weeks: an X-ray to check the bone is healing, which usually takes about 6 weeks. Weight is then increased and the crutches come away over the following weeks
- Weeks 6 to 12: normal walking, stationary bike and steady strength work for the thigh and hip
- Months 3 to 6: back to full activities for most people, including sport, once the bone has healed and strength has returned
- Up to a year: aching after long days keeps easing, and strength keeps building
When can I…
- Go back to work: most people are back within about three months, desk jobs often sooner. Heavy manual work takes longest
- Drive: once you’re off crutches and strong painkillers and can brake hard. Check with your surgeon and insurer
- Play sport: more than 8 in 10 people get back to some sport after an osteotomy. Cycling and swimming come first, running and impact later
- Get the plate out: some people have the plate removed later if it rubs or feels uncomfortable under the skin. Many never need to
The risks
- The bone is slow to heal or doesn’t heal. More likely if you smoke. Occasionally it needs another operation
- Infection of the wound or around the plate
- Blood clots in the leg
- Stiffness, especially if bending isn’t worked on early
- Damage to nerves or blood vessels, which is uncommon
Questions to ask your surgeon
- Is my arthritis limited to the inner side, and how advanced is it?
- Would a partial knee replacement suit me as well, and why do you prefer one over the other for me?
- How much weight can I put on the leg, and for how long?
- How many osteotomies do you do each year?
- What activities can I realistically return to?
If you’re still deciding whether you need surgery at all, see knee arthritis: what actually helps.
Call your surgeon today if
- The wound is red, spreading, hot, weeping or draining, or you have a fever or chills
- Your calf is painful, tender or newly swollen: possible clot in the leg
- Pain is getting WORSE instead of slowly better, or you feel a crack or give after a slip or fall
- Your foot goes numb, or you can’t lift your foot or toes
Go to the emergency department if
- You are suddenly short of breath or have chest pain. A clot can travel to the lung
- Your leg is swelling fast with severe pain that painkillers don’t touch
- Your foot turns cold or pale
Mention it at your next review if
- The knee still won’t go fully straight at around six weeks
- Aching over the plate is limiting what you do months after surgery
- Pain on the inner side is creeping back after a few good years
A replacement swaps the worn joint for a new one. An osteotomy keeps your own knee and moves the load.