The knee has three compartments
Inside (medial), outside (lateral), and behind the kneecap (patellofemoral). Arthritis can wear one compartment while the others stay healthy, or involve the whole joint. That anatomy is the entire decision: partial replacement resurfaces only the worn compartment; total replacement resurfaces the whole joint.
What makes partial appealing
- Your ACL and the rest of your knee stay exactly as they are, which is why partial knees often feel more natural.
- Less bone is removed and less soft tissue disturbed, so recovery is typically faster.
- Smaller operation, generally lower medical stress.
What makes total the right call more often
- Arthritis in more than one compartment, a partial can't fix what it doesn't cover.
- A deficient ACL or significant deformity, which partial designs depend on.
- Inflammatory arthritis, which affects the whole joint.
- Durability planning: a partial knee carries a somewhat higher chance of needing a later conversion to total, usually because arthritis progresses in the compartments it preserved.
The honest comparison
| Partial | Total | |
|---|---|---|
| Treats | One worn compartment | The whole joint |
| Feel | Often more “like my knee” | Excellent, occasionally more “replaced” |
| Recovery | Typically quicker | Somewhat longer |
| Candidacy | Narrow, anatomy decides | Broad |
| Later surgery | Higher chance of eventual conversion | Lower revision rate overall |
How Dr. Seem decides
Candidacy is anatomical, not aspirational. Your history, examination, and imaging establish which compartments are involved and whether your ligaments qualify you. If you're a genuine partial candidate, you'll hear both options with their real trade-offs. If you're not, you'll hear why, a partial knee in the wrong knee is a short-lived favor.
One more honest point
Partial knees punish imprecision, component position and balance drive their survival. This is a
place where robotic assistance and an adult-reconstruction practice genuinely matter to the
odds.