Why Alignment Matters

Normally, on a standing full-length X-ray of the lower limb, known as a scannogram, the weight-bearing axis passes through the centre of the hip joint, the centre of the knee joint, and the centre of the ankle joint. This means the three joints are aligned in a straight line. Any variation from this can lead to abnormal loading of the knee joint, either on the inside, which is more common and associated with bow legs, or on the outside.

Alignment abnormalities are commonly associated with the onset of arthritis and related knee problems. Early intervention in the form of a realignment osteotomy can significantly slow down the progression of arthrosis and allow a person to become active again.

Bow Legs and Knee Osteoarthritis

In nearly 90% of patients with knee osteoarthritis, there is bowing of the legs, meaning the distance between the knees increases and creates a bow leg deformity. This is often associated with a typical waddling gait.

In such cases, a significant amount of body weight is transmitted through the damaged inner half of the knee, leading to collapse and further bowing. If left untreated, this can quickly damage the ligaments and other stabilisers of the knee, causing rapidly progressive osteoarthritis. The eventual treatment in advanced cases is often total knee replacement.

If the alignment is corrected early, cartilage damage can be slowed or prevented, normal function can be improved, and progression of arthrosis can be delayed. Once the location and nature of the deformity are clearly determined, the appropriate realignment osteotomy is performed.

Osteotomy Planning and Surgery

Osteotomy planning is a critical part of treatment. I use Traumacad software and Bone Ninja software to assess the exact nature of the limb deformity, including its location, severity, and associated factors. These tools are highly sensitive and allow me to plan the procedure in great detail.

The surgical procedure itself is fairly straightforward and involves performing the osteotomy and fixing it with a metal or PEEK plate, which is a specialised hardened plastic implant. Most patients can begin walking within 2 days, with a gradual increase in weight bearing. In approximately 6 weeks, the osteotomy heals, and most patients return to normal activities soon after.

Steps Involved in Realignment Osteotomy

• Pre-operative planning with X-rays to determine the degree of correction required.
• Use of a saw to cut through the bone, usually the tibia or femur, depending on the deformity.
• Correction of bone alignment to match the pre-operative plan.
• Opening wedge osteotomy, where the bone is opened to create the desired alignment change.
• Closing wedge osteotomy, where a wedge of bone is removed to change the alignment.
• Fixing the corrected alignment with a metal plate and screws.
• In some opening wedge osteotomies, a bone graft is added to fill the gap when a larger correction is required.