Complex Total Knee Replacement
What is Complex Total Knee Replacement?
Total knee replacement, also called total knee arthroplasty, is a surgical treatment for painful arthritis of the knee in which the worn-out or damaged surfaces of the knee joint are removed and replaced with an artificial prosthesis.
Complex total knee replacement is employed in patients whose arthritis is especially severe, or who have already undergone a previous knee replacement in the same leg. The surgery takes about 2 to 3 hours to perform.
Some conditions involving the knee joint that warrant a complex total knee replacement include the following:
- Weak knee ligaments
- Major knee deformity
- Considerable bone loss due to fracture or arthritis
- Knee fracture that has healed in a deformed or malunited position
- Failed prior knee replacements
- Significant knee stiffness due to joint degeneration
- Gross knee instability due to tearing or stretching of ligaments
- Severe knee injury or knee fracture
- Prosthetic joint infection
In these circumstances, a complex total knee replacement affords a variety of features and benefits, such as utilising more complex prosthetic parts with longer stems to ensure the component is securely fitted in the cavity. Some components may interlock like a hinge at the front of the knee to provide more stability. In addition, larger plastic liners, and bone grafting are often required to ensure correct alignment and length of the lower leg, replace absent bone stock, and to sufficiently restore the collateral ligaments and other soft tissue structures.
Anatomy of the Knee Joint
The lower end of the thighbone, or femur, meets the upper end of the shinbone, or tibia, at the knee joint. A small disk of bone called the patella, commonly known as the kneecap, rests on a groove on the front side of the femoral end. The fibula, another bone of the lower leg, forms a joint with the shinbone. The bones are held together by protective tissues, ligaments, tendons, and muscles. Synovial fluid within the joint aids in the smooth movement of the bones over one another. The meniscus, a soft crescent-shaped area of cartilage between the femur and tibia, serves as a cushion and helps absorb shock during motion.
Preparation for Complex Total Knee Replacement
Preoperative preparation for complex total knee replacement will involve the following steps:
- A thorough examination by your doctor is performed to check for any medical issues that need to be addressed prior to surgery.
- Depending on your medical history, social history, and age, you may need to undergo tests such as bloodwork and imaging to screen for any abnormalities that could threaten the safety of the procedure.
- You will be asked if you have allergies to medications, anaesthesia, or latex.
- You should inform your doctor of any medications, vitamins, or supplements that you are taking.
- You should refrain from medications or supplements such as blood thinners, aspirin, or anti-inflammatory medicines for 1 to 2 weeks prior to surgery.
- You should refrain from alcohol or tobacco at least a week before and 2 weeks after surgery.
- You should not consume solids or liquids at least 8 hours prior to surgery.
- Arrange for someone to drive you home after surgery.
- A written consent will be obtained from you after the surgical procedure has been explained in detail.
Procedure for Complex Total Knee Replacement
The procedure is mostly performed as open surgery since arthroscopic key-hole incisions may not be sufficient to remove the damaged or worn-out prosthesis from a previous knee-replacement surgery. The surgery is performed under regional or general anaesthesia and involves the following steps:
- After adequately sterilising the surgical area, your surgeon makes a long vertical incision over the knee.
- The supporting structures of the knee are gently moved aside to access the joint area.
- Your surgeon will evaluate the joint area for any soft-tissue infection, joint damage, or prosthetic damage to determine which prosthetic parts have worn out or loosened or shifted out of position.
- If the previous prosthesis is in a bad shape, then your surgeon will carefully remove the original prosthesis, taking care to preserve as much bone as possible and any bone cement from a previous knee replacement.
- If the articulating bones have been damaged with severe arthritis or other conditions, then your surgeon will trim the damaged portions from the joint surfaces at appropriate angles to ensure a perfect fit of the new implant.
- Once the original prosthesis is removed, your surgeon will prepare the bone surfaces appropriately to insert specifically sized new prosthetic components into your knee joint, to be secured with bone cement or screws.
- In some cases, bone graft material may be used to aid in rebuilding the knee.
- With the new components in place, the knee joint is tested through its range of motion.
- All surrounding tissues and structures are restored to their normal anatomic positions.
- Finally, the incision is closed with sutures and sterile dressings are applied.
Postoperative Care and Instructions
In general, postoperative care instructions and recovery after complex total knee replacement will involve the following:
- You will be transferred to the recovery area where your nurse will closely observe you for any allergic or anaesthetic reactions and monitor your vital signs as you recover.
- You may notice pain, swelling, and discomfort in the knee area. Pain and anti-inflammatory medications are provided as needed.
- You are advised to keep your leg elevated while resting to prevent swelling and pain.
- You will be given assistive devices such as crutches with instructions on restricted weight-bearing for a specified period of time. You are encouraged to walk with assistance as frequently as possible to prevent blood clots.
- Keep the surgical site clean and dry. Instructions on surgical site care and bathing will be provided.
- Refrain from smoking as it can negatively affect the healing process.
- Eating a healthy diet rich in vitamin D is strongly advised to promote healing and a faster recovery.
- Refrain from strenuous activities for the first few months and lifting heavy weights for at least 6 months. Gradual increase in activities over a period of time is recommended.
- An individualised physical therapy protocol will be designed to help strengthen knee muscles and optimise knee function.
- Most patients can resume their normal activities in a month or two after surgery; however, return to sports may take at least 6 months or longer.
- Refrain from driving until you are fully fit and receive your doctor’s consent.
- A periodic follow-up appointment will be scheduled to monitor your progress.
Risks and Complications
Complex total knee replacement surgery is a relatively safe procedure; however, as with any surgery, some risks and complications may occur, such as the following:
- Failure to relieve pain
- Blood clots
- Anaesthetic/allergic reactions
- Injury to nerves and blood vessels
- Implant wear and loosening
- Failure of the graft
- The need for revision surgery