Unicompartmental Knee Replacement Good Choice for Low-Demand Patients

Improvements in joint replacements have made it possible to have a unicompartmental knee replacement (UKR). Instead of replacing the entire joint surface when only one side of the knee is arthritic, just one compartment is replaced. In most patients, the medial or inside half of the knee is removed and replaced.

But there are pros and cons to this idea. UKR costs less than a total knee replacement (TKR). The UKR is less invasive and recovery time is shorter. The TKR may cost more but it lasts longer. If the UKR has to be revised or eventually replaced with a TKR, then the total cost is greater than if the patient just had a TKR to start with.

In this study, the costs of the UKR are compared with a TKR for elderly low-demand patients. Low-demand refers to older adults who are inactive or sedentary. Medicare reimbursement was used to calculate average costs. The researchers took into consideration the risks and benefits of each treatment method.

They used data from a Norwegian national registry with over 9,000 TKRs and 770 UKRs included. Implant survival rates were available up to 10 years after the operation. Using probability rates for infection and revision, they predicted how long each implant would last up until the death of each patient.

The authors report on the basis of their findings that UKR shouldn't be rejected just because it might not last as long as a TKR. In low-demand patients, a UKR costs less and often outlasts the patient. The model used in this study only accounted for the possibility of a single revision for each UKR or TKR. More studies are needed to compare costs under a variety of conditions.



References: James Slover, MD, MS, et al. Cost-Effectiveness of Unicompartmental and Total Knee Arthroplasty in Elderly Low-Demand Patients. In The Journal of Bone and Joint Surgery. November 2006. Vol. 88-A. No. 11. Pp. 2348-2355.