How It Works:
Also known as unicompartmental knee replacement, this procedure resurfaces only the worn compartment while preserving the healthy cartilage, bone, and cruciate ligaments in the rest of the knee. The result is a less invasive surgery, a faster recovery, and a knee that often feels more natural than a total replacement.
Robotic Precision:
Dr. Leo Zalikha performs partial knee replacement with robotic-assisted technology, which is particularly valuable for this procedure because precision in a smaller operative field directly affects outcome.
Who Is a Candidate?
Partial knee replacement works best for patients with a specific pattern of disease:
- Arthritis confined to one compartment (most commonly the medial, or inner, side of the knee)
- Intact cruciate ligaments (the ACL and PCL must be functioning to maintain stability)
- Correctable deformity (the knee alignment can be addressed by replacing the worn compartment)
- Adequate range of motion (at least 90 degrees of flexion and the ability to fully straighten the knee, or close to it)
Roughly 25 to 30 percent of patients who present with knee arthritis meet the criteria for partial replacement. The evaluation includes a physical exam, standing X-rays of both knees, and a thorough discussion of symptoms and goals.
If arthritis affects more than one compartment, the ligaments are damaged, or the deformity is too significant, a total knee replacement is the better choice.
How Partial Knee Replacement Differs from Total
Feature
Partial Knee
Total Knee
- Bone removed
Only the damaged compartment
All three compartments
- Cruciate ligaments
Preserved
ACL removed, PCL sometimes preserved
- Incision size
Smaller (typically 3 to 4 inches)
Larger (typically 6 to 8 inches)
- Blood loss
Less
More
- Hospital stay
Most patients go home same day
Same day or one night
- Recovery speed
Typically faster
Standard 6-12 week trajectory
- Knee feel
Often described as more natural
Excellent but may feel different
- Longevity
15 to 20+ years in appropriately selected patients
20+ years
- Revision if needed
Can be converted to total knee
Revised with larger components
Robotic-Assisted Partial Knee Replacement
Precision is especially important in partial knee replacement. The implant must be positioned to match the native anatomy of the preserved compartments. If the component is slightly malpositioned, it can alter the mechanics of the healthy side of the knee.
Dr. Zalikha uses robotic-assisted technology for partial knee replacements. Before surgery, a CT scan generates a 3D model of the knee. The surgical plan is built around the patient’s actual anatomy, accounting for bone geometry, alignment, and the relationship between the diseased and healthy compartments.
During surgery, the robotic system provides real-time guidance as bone is prepared, ensuring cuts are made precisely according to plan. The system also provides data on ligament tension, helping Dr. Zalikha fine-tune the balance of the knee so it feels stable and natural through its full range of motion.
What to Expect
Before Surgery
Dr. Zalikha's team provides a pre-operative checklist and scheduling information. A CT scan is obtained for robotic planning. Medical optimization, including addressing weight, blood sugar, and cardiovascular health, improves outcomes.
Day of Surgery
Partial knee replacement typically takes 45 to 75 minutes. Most patients go home the same day. You will walk with the assistance of a physical therapist before discharge.
Recovery
Recovery after partial knee replacement is generally faster than after total knee replacement:
1 to 2 weeks:
Walking with a walker or cane, beginning home exercises, managing swelling
2 to 4 weeks:
Many patients transition off assistive devices, begin driving (left knee replacements sooner than right)
4 to 6 weeks:
Return to most daily activities and many work environments
2 to 3 months:
Resuming recreational activities, continued strength gains
3 to 6 months:
Full recovery for most patients
Physical therapy is important after partial knee replacement, and understanding factors like Knee Replacement Cost can help patients better prepare for recovery. Rehab is often less intensive than after total knee replacement because less tissue is disrupted.
Advantages of Partial Knee Replacement
Keeping the intact compartments, cruciate ligaments, and natural bone stock means the knee retains more of its original anatomy and biomechanics.
Many patients describe a partial knee replacement as feeling more like their natural knee compared to a total replacement. The preserved ligaments contribute to a sense of stability and proprioception (knowing where the knee is in space).
Less bone removal, a smaller incision, and less soft tissue disruption translate to a quicker return to daily activities.
If the other compartments develop arthritis later in life, a partial knee replacement can be converted to a total knee replacement. The conversion surgery is similar in complexity to a primary total knee replacement because healthy bone stock has been preserved.
Limitations and Considerations
- Partial knee replacement is not for everyone. It is a precision operation that requires careful patient selection. If arthritis is present in multiple compartments or the ligaments are damaged, a total knee replacement will produce a more reliable result.
- There is also a slightly higher revision rate compared to total knee replacement over the long term, primarily because new arthritis can develop in the preserved compartments. However, when the procedure is performed on the right patient by an experienced surgeon using robotic-assisted technology, the outcomes are excellent.
- Dr. Zalikha is straightforward about which patients are good candidates and which would be better served by a total replacement. The goal is to match the right procedure to the right knee.