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HealthInfo Waitaha Canterbury

Broken knee

Turi tāwhatiwhati

knee anatomy from the front, showing femur, femoral condyles, patella, articular cartilage, lateral and medial collateral ligaments, patellar ligament, tibial plateau, fibula, and tibiaYour knee joint is made up of the end of your thigh bone (the femur), the top of your tibia (one of the bones of your lower leg) and your kneecap (the patella). Tough bands of tissue called ligaments hold these bones together on the inside and outside of your knee.

This page explains what happens when the end of your femur or the top of your tibia breaks. Another page explains what happens when your kneecap breaks.

Sometimes, when you break the bones of your knee, your ligaments are also damaged.

The smooth round ends of your thigh bone are called the femoral condyles. If you break one of these, it's called a condylar fracture. This tends to happen with high-speed, high-impact activities like downhill skiing or parachuting.

The flat surface at the top of your tibia is called the tibial plateau. This can break if there is a force down through your straight leg, pushing your femoral condyles into the surface of your tibia. For example, if you fall from a height. It can also break if you're hit with great force on the side of the knee. For example, by the bumper of a car.

These fractures usually involve the surface of the joint (also called the articular cartilage), which needs to be repaired very carefully. Sometimes, people go on to develop arthritis and may eventually need surgery to preserve the joint or replace it.

Treating a broken knee

If the broken bones are in a good position, the bone is stable, and the break doesn't involve the joint surface, you'll have a brace or cast to support your knee and stop the bones from moving while they heal. You'll need crutches to move around.

Depending on how your bones are broken, your doctor may recommend you put no weight, or very little weight, on the injured leg. It's very important to follow this advice so your bones heal properly.

You'll have regular follow-up appointments with the orthopaedic team and will have X-rays to see how well the bones are healing.

If your break is not in a good position, is unstable, or involves the joint surface, you'll need an operation to move the bones into the right position and hold them there. If the ends of your thigh bone (femoral condyles) are broken, you may have a metal rod through the middle of your bone, or you may have a plate or screws.

If your tibial plateau is broken, you may have a plate and screws around the bone. If the surface of your tibial plateau has been squashed (compressed), you may need a bone graft to fill the hole. If you need a graft, the bone is likely to be taken from your tibia or occasionally your hip. Your orthopaedic surgeon will talk to you before surgery about what your options are and what they plan to do.

You'll be given antibiotics during your surgery. You may have a drain in after your surgery and are likely to need a brace to support your bones for a few weeks while they heal.

On the next page: Self-care for a broken knee

Written by HealthInfo clinical advisers. Last reviewed July 2022.


See also:

Broken bones first aid

Living with an injury

Page reference: 148653

Review key: HIHIL-240273