## Introduction
For many patients with knee arthritis, the damage is limited to only one side of the joint鈥攗sually the **medial (inner) compartment**. In these cases, a **Unicompartmental Knee Replacement (UKR)**, or partial knee, may be a superior alternative to a **Total Knee Arthroplasty (TKA)**.
## What is UKR?
UKR involves replacing only the damaged compartment while preserving the healthy cartilage, bone, and most importantly, the **Cruciate Ligaments (ACL and PCL)**.
## UKR vs. TKA: Key Differences
| Feature | UKR (Partial) | TKA (Total) |
| :— | :— | :— |
| **Ligament Preservation** | Preserves ACL/PCL | Often sacrifices ACL |
| **Incision Size** | Smaller (MIS) | Larger |
| **Recovery Time** | Faster (2-4 weeks) | Moderate (6-12 weeks) |
| **Joint Kinematics** | More “Natural” feeling | “Mechanical” feeling |
| **Longevity** | Potentially lower than TKA | Gold Standard |
## Why “Natural Feel” Matters
Because the ACL is preserved in a UKR, the knee retains its natural sense of position and stability. Patients often report that they forget they have an artificial joint with UKR, whereas TKA patients often feel the mechanical constraints of the implant.
## Selection Criteria for UKR
UKR is only successful if:
1. Arthritis is strictly limited to the medial compartment.
2. The ACL is intact and functional.
3. The patient does not have severe inflammatory arthritis (like Rheumatoid Arthritis).
## Conclusion
If the damage is localized, “less is more.” Ortholyx provides precision UKR systems that allow for minimal bone resection and rapid return to an active lifestyle.