Full vs. Partial Knee Replacement: What’s the difference?
While it may seem appealing to have half of a surgery compared to a full surgery, it is important to understand the differences between a unicompartmental or partial resurfacing or replacement and a total knee replacement surgery. Each type of knee replacement surgery is unique and has its own outcomes after surgery for knee pain and osteoarthritis.
The knee is composed of three compartments: the inside (medial), outside (lateral) and underneath the knee cap (patellofemoral or anterior). Each of these compartments can be replaced individually in partial knee replacement surgery, or all three can be replaced in total knee replacement surgery. A partial knee replacement is technically one-third of the surgery of a total knee replacement. If you have a partial knee replacement, you will find improvement in the function of your knee and reduction of knee pain, but there are some long-term factors to consider.
Partial Knee Replacement
In the past, partial knee replacement was for patients over 60 years old whose ligaments were in good condition, had little knee deformity and could move their knee pretty well. Today, the procedure is being done on younger patients who have pain and other symptoms in one part of the knee.
Because a partial knee replacement is less surgery with a smaller scar, it has often been reported to have an easier, quicker, more complete recovery and greater satisfaction than a full knee replacement. Complications during surgery like blood loss, transfusion and blood clots (DVT) tend to be less with a partial replacement or resurfacing. The risk to your life (mortality) from the surgery although very small normally is significatly lower with a partial replacement versus a total knee replacement.
Because partial knee replacement retains most of your knee tissue, you are still susceptible to meniscal tears and progression of arthritis in the rest of the knee. When a partial knee replacement fails, it can be converted to a full knee replacement with an excellent degree of success. The surgery and recovery may be more involved, but the overall outcomes are highly successful.
Total Knee Replacement
This procedure has been revolutionary to orthopaedics giving many patients the ability to return to function and enjoy their lives with implants lasting about 10-15-years. While the surgery is longer, there is a higher rate of complications and greater cost, the lifetime of the implants is much greater than in partial knee replacements. Physiotherapy is tougher early on, and the knee ultimately doesn’t quite feel the same as your own knee. Despite these potential limitations, patients who are good candidates for total knee replacement have great patient satisfaction, high functional scores and longer-lasting replacements. In the United States, over 90% of knee replacement surgeries are total knee replacements; while 10% or less are partial knee replacements. However studies from Oxford have shown that one of the most important factors in your success is the skill and experience of your surgeon. Those surgeons who are doing a higher proportion of partial knee resurfacings have a better patient satisfaction and long term outcomes. It has also shown that nearly 50% of those treated in England with a total knee replacement could have been a candidate for a partial knee resurfacing or replacement.
Both partial and total knee replacements can be highly successfully for patients who are good candidates. If you take care of your total or partial knee replacement it will provide you with the greatest longevity possible.
Source data from the AAHKS