Partial Knee Replacement
Partial (unicompartmental) knee replacement with Dr. Steven Ward in Tucson and Oro Valley — resurfacing only the worn part of the knee and keeping the healthy cartilage and ligaments, including the ACL and PCL.
Call 520-881-1394Typical ranges for general education. Dr. Ward’s plan for you may differ.
What it treats
The knee has three compartments: the inner (medial), the outer (lateral), and the area behind the kneecap (patellofemoral). When arthritis has worn away the cartilage in only one compartment, most often the inner side, a partial knee replacement can resurface just that area.
- Arthritis limited to one compartment, with pain mostly on the inner or outer side of the knee
- An intact ACL and healthy ligaments
- Good knee motion without significant stiffness
A partial knee is usually not the right fit for inflammatory arthritis (such as rheumatoid arthritis), significant stiffness, ligament damage, or arthritis in more than one compartment. In those cases a total knee replacement is usually the better option. An X-ray is usually enough to decide; sometimes an MRI or arthroscopy is used to confirm the other compartments and the ACL.
Is surgery right for you?
Surgery is not automatic. Treatment starts with non-operative care:
- Activity changes and anti-inflammatory medication when it is safe for you
- Physical therapy to strengthen the muscles that support the knee
- Bracing
- Injections
Replacement is considered when arthritis keeps interfering with work, sleep, or the activities you enjoy despite these steps. Dr. Ward and his physician assistants review your X-rays and options with you, and there is no single path that fits everyone.
How the surgery is done
A partial knee replacement typically takes 1–2 hours. The anesthesia team will discuss options with you, such as a spinal anesthetic or nerve block, sometimes combined with general anesthesia.
Through an incision at the front of the knee, Dr. Ward first checks all three compartments to confirm that the damage is limited to one area and that the ligaments are intact. He then removes the worn cartilage and a thin layer of bone from that compartment and fits metal components to recreate the joint surfaces, with a smooth plastic insert between them. Everything else in the knee is left in place.
If the inside of the knee shows that a partial replacement is not the right choice, a total knee replacement may be done instead. Dr. Ward will talk through this back-up plan with you before surgery.
Partial vs. total knee
Partial: resurfaces one compartment and keeps the ACL and PCL. Recovery is typically about six weeks, and many people say the knee feels more natural.
Total: resurfaces all three compartments. Recovery is typically about twelve weeks.
Converting a partial to a total later is uncommon, but the compartments that were not replaced can still wear over time. See total knee replacement for a full comparison.
Recovery overview
Typical ranges after a partial knee replacement. Dr. Ward’s plan for you may differ.
First days
- You start putting weight on the knee right after surgery
- Many people go home the same day or after one night
- A walker, cane, or crutches for the first several days or weeks
- Ice and elevation for swelling; you will get a plan to lower your blood clot risk
Weeks 1–6
- Physical therapy and home exercises to restore motion and strength
- Wean off the walking aid as you become steady
- Follow-up visits with Dr. Ward
Around 6 weeks and beyond
- Recovery is typically about six weeks
- Most people are back to their regular daily activities by about 6 weeks
- Keep up your exercises, and ask Dr. Ward about returning to your recreational activities
When to call the clinic
Call 520-881-1394 if you notice any of the following after surgery or while you are recovering:
- A fever of 101°F or higher, or chills
- Redness spreading around an incision, or drainage that is cloudy, foul-smelling, or keeps soaking the dressing after the first few days
- New or worsening numbness, tingling, or weakness in the leg or foot once the anesthesia has worn off, or a foot that turns pale, blue, or cold
- Pain that is not controlled by your prescribed medication, ice, elevation, and rest
- Pain, swelling, or tenderness in the calf that is new or getting worse
It is normal for the knee to be swollen, bruised, and sore for a while, and for the leg to feel numb or weak until a nerve block or spinal anesthetic wears off. Use your crutches, walker, or brace as directed. Call if something feels different from what you were told to expect.
for chest pain, shortness of breath, or trouble breathing. These can be signs of a blood clot in the lungs and need emergency care.
If something does not match the instructions you were given, call the office. Dr. Ward or one of his physician assistants will get back to you.
Related resources
Total and Partial Knee Replacement Post-Op Instructions
Dr. Ward’s printable handout for the weeks after knee replacement, including medications, wound care, activity, and when to call.
Open PDFTotal knee replacement
Total vs. partial knee replacement and what the first twelve weeks look like.
Open pageTotal knee exercises
Printable knee replacement exercise programs and worksheets.
Open pageKnee post-op hub
Knee arthroscopy and knee replacement packets, rehab protocols, and anatomy guides.
Open pageExercise guides
Printable home exercise programs to use with your physical therapist.
Open pageOrthoInfo: Partial knee replacement
Patient education on unicompartmental knee replacement from the AAOS.
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