What is Cementless Total Knee Arthroplasty?
Cementless total knee arthroplasty uses a special kind of knee implant, also called press-fit implant, that is fixed to the bone without the use of bone cement. The cementless knee implants have a porous surface with specific holes and are attached to the bones with screws. As time progresses, the bone cells grow into the implant. The bone-metal interface becomes a single healed unit as a result of biologic fixation.
What are the Indications for Cementless Total Knee Arthroplasty?
Cementless total knee arthroplasty is recommended only after non-surgical approaches such as medications, exercise, steroid injections, weight control, and lifestyle modifications are unsuccessful in relieving symptoms of arthritis and other related joint problems such as pain, weakness, and instability.
Indications for cementless total knee arthroplasty surgery include:
- Wear and tear of joints due to arthritis, trauma, or other medical conditions
- Significant knee pain
- Age less than 65 years
- Good bone quality
- Physically active
Cementless total knee arthroplasty IS NOT recommended for people with poor bone quality due to:
- Bone infection/osteomyelitis
- Bone deterioration (osteolysis)
Pre-Surgical Preparation for Cementless Total Knee Arthroplasty
In general, preoperative preparation for a cementless total knee arthroplasty will involve the following:
- A thorough medical examination by your doctor including your medical history, physical examination, blood tests, and other diagnostic tests.
- Inform your doctor if you have a history of bleeding disorders or if you are on any blood thinners (anticoagulant medications), aspirin, or other medications that affect blood clotting. You may need to refrain from these medications prior to the procedure.
- Inform your doctor about any allergies and your current medications.
- You should not consume any solids or liquids at least 8 hours prior to surgery.
- You should refrain from smoking, as tobacco affects blood circulation and increases the risk of complications.
Cementless Total Knee Arthroplasty Procedure
Cementless total knee arthroplasty is performed under general anesthesia.
- You are placed in supine position on your back with your knees slightlyraised to facilitate incision placement.
- Your surgeon makes an incision in the skin over the affected knee to expose the knee joint.
- Then, the damaged portions of the femur bone are cut at appropriate angles using specialized jigs.
- The femoral component of the knee implant is attached to the end of the femur with or without a screw.
- Your surgeon then cuts or shaves the damaged area of the tibia (shinbone) and the cartilage. This removes the deformed part of the bone and any bony growths, as well as creates a smooth surface on which the implants can be attached.
- Next, the tibial component of the knee implant is secured to the end of the bone with or without screws.
- Care is taken that there is no gap between the implant components and the bones in your knee joint. This is done to ensure there is proper biological fixation as the bone begins to grow into the implant.
- Once the implants have been placed, the surgical instruments are removed.
- The incision is closed and covered with a sterile waterproof bandage.
Recovery and Post-Surgical Care for Cementless Total Knee Arthroplasty
Post-surgery, you will be monitored and discharged after 1 to 3 days. In some cases, patients may be discharged on the day of surgery. Post-operative imaging tests are usually ordered to determine the success of your knee surgery.
- You will be prescribed pain medications to keep you comfortable.
- You will be encouraged to walk immediately after surgery. A cane, crutches, or a walker will be needed for weight-bearing in the first few weeks.
- Perform mild exercises as per your physical therapist’s recommendations to remain active. You can gradually increase the intensity of your regular activities.
- Patients can return to normal activities within 3-4 weeks. Complete recovery may take up to 8 weeks.
You should visit your specialist for regular follow-ups to ensure a smooth recovery.
What are the Benefits/Advantages of Cementless Total Knee Arthroplasty?
Traditional knee replacements use bone cement. The drawback of using bone cement is that it can loosen over time, especially if you are involved in extensive physical activities. Thus, performing a cementless total knee arthroplasty has the following advantages:
- Shorter duration of surgery
- Preserves bone stock
- Longevity/long-lasting implants
- Easy to perform a revision surgery, if required
- Minimizes the risk of implant loosening
- The cementless implant may last for a long period ranging from 10-15 years up to one’s lifetime
- Minimizes the presence of any potential loose fragments
- Quicker recovery
- Better quality of life
What are the Risks and Complications of Cementless Total Knee Arthroplasty?
Cementless total knee arthroplasty is a relatively new technique when compared to cemented total knee arthroplasty. Hence, there is lesser evidence to support the long-term effectiveness of cementless implants. Some of the challenges or drawbacks may include:
- The fusion between the knee implant and the bone via biologic fixation may take a long time.
- The success of the procedure may reduce if there is a gap between the implant and the bone in absence of cement.
- The bone implant may loosen over time.
- Cementless knee implants are more expensive compared to the cemented total knee arthroplasty. The reason is the implants are manufactured using a special technology.