A total knee replacement, also known as total knee arthroplasty, is a knee surgery performed by an orthopedic surgeon to alleviate pain caused by arthritis and other knee damaging conditions. During a total knee replacement, Dr. Martin makes an incision to access your tibia (shin bone), patella (kneecap), and femur (thigh bone). After the damaged bones are exposed the bone is resected to a healthy portion which is then capped with metal components that recreate the joint surface. A layer of plastic is placed between the metal components to replace the cartilage layer to allow for the smooth movement of the joint.
The traditional approach to a knee replacement required a large incision and significant soft tissue disruption which led to a longer and more painful recovery. A minimally invasive approach to knee replacement uses robotic-assisted arms to make smaller incisions with less soft tissue disruption. The advantage of minimally invasive surgery is that the approach allows for faster recovery, less pain, less blood loss, and the opportunity for same-day surgery. Most patients who are candidates for a traditional total knee replacement are candidates for a minimally invasive approach however the determination is made by the surgeon.
Traditional Knee Replacement
When performing a traditional knee replacement, initially the surgeon makes an 8- to 10-inch vertical incision over the front of the knee to expose the joint. This incision extends into the quadriceps tendon which provides the surgeon good visualization. Visualization is important for a traditional knee replacement to ensure proper positioning for the longevity of the joint.
The surgeon will then:
- Resect the damaged cartilage surface and bone from the femur and tibia.
- Remove and resurface the soft tissues of the knee that may impede the implants.
- Position the metal implants, typically with an external jig system. The removed cartilage and bone are replaced with metal components that recreate the surface of the joint.
- Rest and replace the undersurface of the patella (kneecap) with a plastic button. Some surgeons do not resurface the patella, depending on the case.
- Place the plastic spacer between the metal components to create a smooth gliding surface.
Minimally Invasive Knee Replacement Surgery
- When performing minimally invasive knee replacement, the surgical procedure is similar, but there is less cutting of the tissue surrounding the knee. The incision is typically 4-6 inches.
- The surgeon avoids cutting into the quadriceps muscles because much of the power of the knee comes from the quadriceps. When this muscle and tendon group cut or damage as in traditional knee replacement it takes longer to recover strength and stamina of the muscle group. Dr. Martin utilizes a midvastus approach.
- Due to the limited visualization of a smaller incision, other means are needed to ensure proper placement of the implants. Dr. Martin utilizes the Makoplasty robotics system which provides proper positioning of implants based on the patient’s anatomy from a CT scan.
- The artificial implants used are the same as those used for traditional knee replacement. Dr. Martin uses Stryker Triathlon for his patients.
- Patients are often allowed to go home the same day as surgery, full weight on the leg, using a walker for balance purposes.
- Physical therapy recommendations are patient-dependent, but all patients are recommended a home exercise program. They are encouraged to participate in non-impact exercises IE the recumbent exercise bike to help increase range of motion and reduce stiffness.
Good Candidates For Minimally Invasive Surgery
Most patients who are candidates for a traditional total knee replacement are candidates for a minimally invasive approach with the robotics system. Dr. Martin, however, determines candidacy based on several factors including body structure, knee deformity, previous surgeries, and other disease processes that may affect the replacement and subsequent healing.
Quicker Surgery Recovery Time
Recovery from a minimally invasive total knee replacement is much different now than traditional replacements were a few years ago.
- Dr. Martin’s patients no longer stay overnight in the hospital unless there are specific social or medical requirements.
- Patients are up and walking within hours of the surgery with the aid of a walker for balance.
- Exercises begin the same day as surgery, progressing to more aggressive exercises as the patient heals. Depending on how the patient is recovering Dr. Martin may recommend formal outpatient physical therapy.
- There are no stitches or staples to be removed as Dr. Martin uses all absorbable sutures. Patients begin showering 3 days after surgery when the dressings are removed.
- Depending on the surgical leg and pain control, patients resume driving within 1-2 weeks for surgery.
- Returning to work is largely based on the type of job a patient has. Stationary or desk jobs can be resumed as early as 1 week but more physical jobs may take up to 6 weeks.