Rotationplasty is a specialized, limb-sparing surgical procedure used primarily to treat conditions affecting the lower limb, often around the knee joint. It is an alternative to traditional above-the-knee amputation, aiming to provide a patient with greater long-term function. The procedure involves removing a diseased section of the leg and reattaching the remaining healthy lower portion. The goal is to repurpose the patient’s ankle joint to function as a replacement knee joint, significantly improving mobility and offering greater durability and sensation than purely artificial replacements.
The Medical Necessity for Rotationplasty
The decision to perform a rotationplasty is made when a segment of the leg, including the knee joint, must be removed, but the lower leg, ankle, and foot are otherwise healthy. This surgery is most frequently indicated for children and adolescents diagnosed with malignant bone tumors, such as osteosarcoma or Ewing sarcoma, located near the knee. Removing the tumor often necessitates the removal of the surrounding bone structure, including the distal femur, knee joint, and proximal tibia.
Rotationplasty is also considered for patients with severe congenital limb deficiencies, like proximal femoral focal deficiency, where a significant portion of the femur is underdeveloped. Choosing this procedure over a traditional high amputation maximizes a child’s function and preserves their growth potential. Unlike metal endoprostheses, the patient’s own bone continues to grow, adapting better to activities and reducing the need for multiple future surgeries.
The Surgical Process Explained
The procedure begins with the precise removal of the diseased section of the limb, known as the resection phase. Surgeons carefully excise the tumor and surrounding bone, ensuring a margin of healthy tissue is taken to minimize cancer recurrence. During this step, the lower limb’s major nerves and blood vessels are isolated and preserved to maintain sensation and circulation in the foot and ankle.
The next step involves the rotation of the lower limb segment. The remaining lower leg is rotated 180 degrees so the foot faces backward. This rotation is performed because the ankle joint naturally flexes in the opposite direction of the knee joint. By turning the segment 180 degrees, the ankle’s up-and-down movement mimics the forward-and-backward motion of a normal knee.
Following the rotation, the fixation phase involves reattaching the rotated lower leg to the remaining upper thigh bone (femur). The tibia is secured to the femur using internal fixation devices like plates and screws until the bones heal together. This connection creates a shortened limb with the ankle positioned where the knee would have been, preparing the foot and ankle to act as a biologically powered hinge for a prosthetic limb.
Functional Outcomes and Rehabilitation
The primary outcome is the conversion of the ankle joint into a highly functional, active knee joint. The backward-facing foot and ankle fit into a specialized prosthetic socket. When the patient moves their ankle, the action of plantarflexion and dorsiflexion translates into the flexion and extension of the prosthetic knee.
This biological joint provides sensory feedback and control superior to a purely mechanical prosthetic knee. Patients can feel the position of their joint and contract the muscles of the foot and calf to control prosthetic movement. This enhanced control allows for high mobility, enabling many patients to participate in activities like running, jumping, and competitive sports.
Rehabilitation is a structured process, often beginning within weeks of the surgery. Physical therapy focuses on strengthening the muscles of the thigh and hip, and regaining full range of motion in the newly positioned ankle joint. Patients must learn to consciously use their ankle and foot muscles to operate the prosthetic knee, which requires significant practice and adaptation.
The rehabilitation program typically spans several months, focusing on gait training and balance once the prosthetic is fitted. Long-term monitoring is important for growing children, as the prosthetic must be adjusted and potentially lengthened as the child grows. Studies demonstrate that patients achieve significant improvements in walking ability and muscle strength, often reaching near-normal levels within one year.