High Tibial Osteotomy

When it is worth considering

This is an operation for a particular kind of patient: someone relatively young and active, with arthritis limited to one side of the knee, whose leg has bowed inwards so that all their weight tracks through the worn side. Replacing that knee would work, but a replacement in a forty-year-old is a replacement that will need revising, possibly more than once. Realigning the leg buys years on your own joint instead.

It tends to be suitable when:

• You are broadly under fifty-five and want to stay active, including at work
• Wear is on the inner side of the knee, with the outer side still in good condition
• The leg is visibly bow-legged, and the alignment is the reason that side is wearing
• The knee still bends well and is stable, with intact ligaments
• You would rather delay a replacement than have one now

It is not the right operation for arthritis spread across the whole knee, for inflammatory arthritis, or for a knee that is already stiff. In an older or less active patient a replacement is usually the more sensible choice, and that gets said directly.

What the operation involves

The planning matters more here than in most operations, because the whole point is a specific correction in degrees. Full-length standing X-rays are used to measure the current alignment and work out exactly how much the bone needs to move.

In theatre the tibia is cut just below the knee and opened, or occasionally closed, to the planned angle, then held with a plate and screws while it heals. Bone graft or a substitute is sometimes used to fill the gap. The joint itself is not opened for the correction, though an arthroscopy is sometimes done at the same sitting to deal with a torn meniscus or loose cartilage.

Recovery, week by week

Recovery here is longer than after a knee replacement, because a cut bone has to unite before the leg can take full load. These are typical ranges.

• Week 0 to 2. Hospital stay of a few days. Walking with crutches, putting only limited weight through the leg. Knee bending exercises start early.
• Week 2 to 6. Still on crutches with protected weight-bearing. X-rays check that the cut is healing in the planned position.
• Week 6 to 12. Weight through the leg is increased as the X-rays allow, usually off crutches somewhere in this window. Strengthening work begins in earnest.
• 3 to 6 months. The bone is normally united. Walking distance, stairs and general activity build back up.
• 6 to 12 months. Return to sport and heavier physical work, once strength and healing allow it.

The instruction about how much weight to put through the leg is not advisory. Loading a cut bone too early is the main way this operation goes wrong.

What it buys you

A well-aligned osteotomy commonly gives a decade or more of good function on your own knee, and often longer in someone who stays a reasonable weight. It does not cure the arthritis, and it does not promise the knee will never need replacing. What it does is push that decision into the future, at an age when a replacement is a better proposition than it is now.

A knee replacement remains entirely possible afterwards if it is eventually needed. The plate is usually removed first if it is still in place, and the operation is a little more involved than a straightforward replacement, but it is done routinely.

Risks worth knowing about

The ones specific to this operation are the bone failing to unite or uniting slowly, correction that ends up short of or beyond what was planned, and irritation from the plate, which is sometimes removed once healing is complete. Infection, clots in the leg or lung, stiffness and injury to nerves or vessels apply here as they do to any knee surgery.

Smoking matters more for this operation than for most, because it directly impairs bone healing. If you smoke, stopping before surgery is part of the treatment rather than general advice.

Common questions