What is Ankle Joint Replacement using Patient-Specific Instrumentation (PSI)?
Ankle joint replacement, also referred to as ankle joint arthroplasty, is a surgical procedure in which the worn-out or damaged parts of the ankle joint are removed and replaced with artificial ankle components called prostheses or implants made of metal, ceramic, or plastic.
An effective ankle joint replacement is directly connected with the use of precise implant designs and implant positioning. Ankle joint replacement using patient specific instrumentation (PSI) is an advanced ankle joint replacement technique that involves the use of preoperative navigation system and custom-made cutting guides to achieve precision in implant designs and placement. PSI enables to accomplish customized implants with respect to each patient's unique anatomy based on preoperative ankle computed tomography scans and guide the use of instruments intraoperatively to improve the accuracy of bone cutting and implant positioning. PSI improves the reliability of accomplishing neutral ankle alignment and more precise implant sizing and positioning, enabling a successful ankle joint replacement.
Indications for Ankle Joint Replacement using Patient-Specific Instrumentation (PSI)
Ankle joint replacement using patient-specific instrumentation is usually indicated for the treatment of ankle arthritis that has not responded to non-surgical treatments such as medications and injections. Arthritis is a degenerative condition in which the articular cartilage that covers the joint surface is damaged or worn out causing pain and inflammation.
The ankle joint connects the leg with the foot and provides free movement to the foot. It is formed by connecting the bones of the lower leg, tibia and fibula, with the talus or ankle bone. The surface of the ankle bones is covered with articular cartilage. Damage to the cartilage leads to an arthritic ankle, which results in pain and impaired movement of the ankle. Infection, bone fracture, connective tissue disorder, excessive stress, and certain disease conditions such as rheumatoid arthritis and osteoarthritis, may cause ankle arthritis.
Preparation for Ankle Joint Replacement using Patient-Specific Instrumentation (PSI)
Preoperative preparation for ankle joint replacement using patient-specific instrumentation may involve the following steps:
- A review of your medical history and a physical examination is performed by your doctor to check for any medical issues that need to be addressed prior to surgery.
- Diagnostic tests such as blood work to help detect any abnormalities that could compromise the safety of the surgery and imaging of the foot and ankle to design a personalized plan based on the specifics of an individual’s ankle anatomy.
- You will be asked if you have allergies to medications, anesthesia, or latex.
- You should inform your doctor of any medications or supplements you are taking or any conditions you have such as heart or lung disease.
- Your physician may adjust the dose of the medications you are on or ask you to stop taking certain medications such as blood thinners or other supplements for a defined period prior to surgery, if contraindicated for the procedure.
- You should refrain from alcohol or tobacco at least a few days prior to the surgery and several days after as it can hinder the healing process.
- You should not consume any solids or liquids at least 8 hours prior to surgery.
- You should arrange for someone to drive you home after surgery.
- A signed informed consent form will be obtained from you after the pros and cons of the surgery have been explained.
Procedure for Ankle Joint Replacement using Patient-Specific Instrumentation (PSI)
Prior to ankle joint replacement using patient-specific instrumentation (PSI), several CT scans are taken to understand the specific anatomy of the affected ankle joint. Based on the CT images, your surgeon plans the surgery and calculates the cutting measurements, which help your surgeon to remove the exact amount of bone, at specific angles. This customized cut provides better implantation, more reliable alignment, and removal of less bone.
The surgery is usually performed under general or regional anesthesia. Your surgeon makes an incision over the front of the ankle. The muscles are retracted, and tendons and ligaments moved away to expose the ankle joint. The damaged regions of the tibia, fibula, and talus bone are then removed using special instruments, and the remaining healthy bones are reshaped to fit the patient-specific ankle implants. A bone graft is inserted between the tibia and fibula to create a fusion of the two bones and prevent loosening of the implants. The implants are kept in position using special bone cement and instrumentation such as screws to support the artificial ankle joint. With all the new components in place, the ankle joint is tested through its range of motion. At the end of the surgery, tendons and other structures are positioned back to cover the new joint. The wound is sutured closed and covered with a sterile dressing.
Postoperative Care and Recovery
Following ankle joint replacement using patient-specific instrumentation (PSI), you may need to stay in the hospital for 2-3 days and will be advised on precautions for a successful recovery. The treated ankle will be immobilized with the help of splints and a bulky dressing. You are advised not to put any weight on the ankle for at least 6 weeks and use crutches for walking. Usually, a drain tube is inserted into the joint during surgery to drain blood from the incision, which is removed within 1-2 days after the surgery. Swelling and discomfort can be managed by taking prescription pain medicines, applying ice packs, and also by elevating the ankle above heart level while resting. You will be referred to physical therapy soon after surgery to regain range of motion of the new ankle. Sutures are removed after 10-15 days. You should take care that the incision is kept clean and dry. Refrain from strenuous activities for at least 6 months. A gradual increase in activities is recommended, with your doctor’s guidance. Avoid smoking and alcohol consumption and make sure to eat a healthy diet for the best outcome.
Risks and Complications
Ankle joint replacement using patient-specific instrumentation is a relatively safe procedure; however, as with any surgery, some risks and complications may occur, such as:
- Infection
- Bleeding
- Deep vein thrombosis (DVT) or blood clots
- Allergic/anesthetic reactions
- Hardware failure
- Fracture of the tibia or fibula
- Dislocation of the ankle
- Instability
- Stiffness
- Injury to surrounding soft tissues, such as nerves or blood vessels
