Partial Knee Replacement – Procedure, Advantages, Precautions & Risks
Partial Knee Resurfacing is a surgical procedure which involves the resurfacing of only the worn out bony surface of the Knee Joint.
In a Partial Knee Replacement procedure, either the inner part of the knee (medial); outer part of the knee (lateral); or area between the kneecap and the upper front surface of the femur (patella-femoral) is replaced. This means only the damaged part of the knee cartilage is replaced with the prosthesis and not all parts as in a Total Knee Replacement Surgery.
To be a suitable candidate one must have an intact anterior cruciate ligament, a sufficient range of knee motion, limited inflammation, damage to only one compartment and no calcification of cartilage or knee dislocation. Patients with medial, lateral, or patella-femoral knee osteoarthritis can be considered for a partial knee replacement.
Compared to a Total Knee Replacement Surgery, Partial Knee Replacement Surgery preserves better knee bending and functioning because it facilitates healthy natural tissue (ligaments) and bone in the knee. For these reasons patients tend to be more satisfied with partial knee replacement as compared to a total knee replacement and they are still candidates for total knee replacement should they ever need it in the future. Further testing may be required if the diagnosis is not clear:
- X-Ray – this needs to be weight bearing. The use of a weight-bearing x-ray can determine the extent of the degeneration in the joint
- Blood Test – This may be needed to determine if there is inflammatory arthritis or infection in the knee MRI – This is dome to determine if one has an intact ACL
Partial Knee Replacement is considered as a ‘resurfacing’ surgery. This means the diseased bone is resurfaced only, leaving the rest of the joint untouched. The device is small consisting of metal and plastic components and the operation itself is less invasive.
Smaller Incision: The incision itself is approximately 8cms long Less Blood Loss: Partial Knee Replacement Surgery is done by the minimally invasive approach and the need for blood transfusion is practically never there Less Bone Removed: Partial Knee Replacement Surgery means ‘resurfacing’ the bone with metal on plastic. Therefore, only a small amount of bone needs to be removed, approximately 3 – 4 mm, to fit the device. Total Knee Replacement requires the loss of approximately 10 mm from all compartments Lower Morbidity: Partial Knee Replacement Surgery greatly reduces the disruption to the joints, providing a shorter recovery period and a decrease in complications
Shorter Recovery Time: Most Partial knee replacement patients are walking 6 hours after surgery. Total time spent in hospital is approximately 24- 48 hours & within 4 weeks patients are back driving, playing golf, or resuming normal activities
The advantage of a partial knee replacement rather than a total knee replacement is less. There is no damage made to the healthy ligaments during the procedure and the operated knee will function and feel more like the patient’s natural knee.
A partial knee replacement implant is much smaller than a total knee replacement implant and does not disturb the healthy tissues of the patient’s knee. Implants are a cobalt chrome alloy that conforms precisely to the anatomy of the knee and the bearing surfaces are Metal- on-poly.
Partial Knee Replacement Surgery requires resurfacing of the damaged knee joint. An artificial knee joint is designed to fit into the edges of the partially damaged joint and replace the damaged areas without causing much pain and discomfort.
The surgery takes approximately 1 hour and an additional 45 minutes to an hour for recovery. A patient will be out of the bed and in a condition to walk in about 4-6 hours post surgery. An incision of approximately 8 cms has to be made below the centre of the knee, above the kneecap. Upon waking up the patient will have a drain attached to the knee which will be removed before the patient goes home.
The surgery will be performed under general anesthesia/ spinal anesthesia.
- Post-operative pain is one of the major outcomes of surgery.
- Relief of the patient’s distress is an important goal in its own right, severe pain often leaves the patient permanently scarred and terrified of even minor surgery.
- Meticulous pain management is pivotal in helping physical therapy and achieving a faster return to function.
Our objectives are:
- No pain or low levels of discomfort for the entire peri-operative and convalescent period
- Side effects limited or reduced to negligible levels
- Rigorous rehabilitation and early discharge
Precautions to take following Knee Surgery:
- Avoid chairs that are low
- Avoid slippery surfaces
- Avoid twisting knee for 6-8 weeks after surgery
- Avoid sitting in the same position for long periods. 45 minutes at a time should be enough.
- Sitting for long periods increases the likelihood of stiffness
- The incision is sutured with skin staples which will be removed 12-15 days after surgery.
- The nurses in the hospital will help the patient change the dressing if needed before leaving the hospital.
- Patient must not get the incision wet until the staples are removed – a sponge bath instead of a shower is therefore recommended for 15 days post surgery.
Gentle exercises help strengthen the muscles around the new knee and regain the knee’s range of motion.
An infection at the surgical site is possible. Blood clots are a risk as are injuries to a blood vessel or a nerve. These complications are quite rare Some knee joint stiffness may be experienced Late complications may include infection and a failure, loosening or dislocation of the prosthesis as well as continued pain