Osteotomies can be performed around the knee to compensate for arthritic changes, ligament injuries or a combination of the two. Most often, an osteotomy around the knee is a High Tibial Osteotomy (HTO), for arthritis of the medial side of the knee. The technique can be used for individuals who are too young for a partial or total knee replacement to be considered, and moves body weight onto the healthier side of the knee.
The diagnosis of early OA is made after taking a history and examination, combined with Xrays, and sometimes an MRI scan. An arthroscopy to view inside the knee can have been performed either before, or at the same time as the osteotomy, to perform a micro-fracture and try and achieve some healing of the damaged bone if appropriate.
Because joint replacements are more likely to fail if implanted into younger individuals, an osteotomy maybe a preferred option in those less than 50 years old. Patients should also have earlier OA disease confined to one area of the knee, and a good range of motion in the joint. Because of concerns regarding reduced success of Total Knee replacements and partial replacements in patients with high Body Mass Index (BMI), osteotomy maybe more appropriate in very heavy patients.
Contraindications include those who smoke (as smoking reduces bone healing), patients with inflammatory diseases such as rheumatoid arthritis, patients with OA throughout the knee, or marked instability.
The operation involves using a saw to cut the tibia or femur, close to the knee, leaving a small bridge of bone intact. The cut is then opened to create a gap, and realign the bone. The selected correction is then fixed with a plate and screws. The gap, or wedge, that is created can be filled with bone graft, or left free and will heal with new bone.
The success of high tibial osteotomy depends on a number of factors including age, severity of disease and activity level. The operation usually results in good pain relief, and an improvement in function, whilst delaying the need for joint replacement, and retaining the native knee. Around 5-10% of patients do not feel a benefit of surgery, and 2-3% may have increased pain, or feel worse, after an osteotomy. Approximately 75% of patients will feel a benefit for 8-10 years, and will be able to defer the need for joint replacement.
Performing a joint replacement after an osteotomy maybe more slightly more difficult, but tends to produce better results than having to revise a previous Total Knee Replacement to a revision implant.
Bleeding and swelling. A drain maybe inserted to remove excess blood
Slow healing of the bone
Nerve or vessel damage
Intra-operative fracture. The tibial bone cut may extend all the way across the bone. This is controlled by the plate and screws.
DVT/PE – injections, and the oral medication are supplied to reduce the risk of blood clots.
Persisting pain. Some discomfort from the abnormal bone may persist
Length of operation. The operation takes approximately 60 – 90 minutes.
What type of anaesthesia is used? The decision as to what type of anaesthetic is used lies with the anaesthetic after assessing a patient. General anaesthetics maybe used, or a spinal injection to numb sensation below the waist. This provides good pain control for some hours after the operation and is often combined with sedation through the procedure.
Length of stay. In patient stay is usually 1 night, for pain control, and post-operative physiotherapy.
When can I drive a car? Driving allowed around 6-8 weeks
Crutches – are required to prevent putting too much pressure through the leg initially and to get the muscles working. Full weight bearing maybe allowed at 6-8 weeks depending on bone healing. Progress and healing is monitored with XRays and clinical assessment.
Cryocuff – maybe used to help keep swelling down.