Sometimes people with osteoarthritis (OA) of the knee only need part of the joint replaced. Instead of a total knee replacement (TKR), they get a unicompartmental arthroplasty. Usually the medial side of the joint (closest to the other knee) wears down first and needs to be replaced.
In this report, researchers compared the cost of unicompartmental versus TKR. They used the results of other studies collected in the literature. Out of 345 articles on the topic, nine articles were used for the analysis.
Treatment costs and benefits for each procedure were calculated using a special formula. Utility value, discounting, and hospital costs were calculated as part of the factors. Quality of life, durability of the implant, and improved function were measures used to compare the benefit of these two implants.
The authors report that a unicompartmental implant represents about a 25 per cent cost savings over a TKR. Shorter hospital stay, lower physician cost, and savings on the cost of the unicompartmental implant account for the difference.
The TKR is expected to last at least 15 years. The expected survival rate of the unicompartmental implant is closer to 12 years. The unicompartmental implant has to survive within three or four years of a TKR for equal benefit to occur when comparing costs.
All in all, the authors say the unicompartmental implant is a good choice for some patients with unicompartmental knee arthritis. Durability and function are improved just as much as for patients who get a TKR but at one-fourth less cost.