I’ve been told that younger, active patients with arthritis can have part of the joint replaced when uneven wear causes problems. How young do you have to be? I’m 62-years-old and not quite ready for a complete knee replacement. Am I too old for this operation?

The unicompartmental knee arthroplasty (UKA) has several advantages over a total knee replacement (TKR). As you mentioned, it is an acceptable alternative to TKR when only one side of the joint needs to be replaced.

UKA is less invasive and removes less bone compared to a TKR. Improved computer-assisted surgical methods and improved implant quality have made it possible for younger patients to benefit from the UKA.

The exact definition of younger has not been statistically determined. Each patient is evaluated by the orthopedic surgeon for this type of implant. Studies report surgeons are using the UKA in adults ages 47 to 83.

Older age is not as much of a challenge as younger age. The reason for this is concern over how many years of wear and tear the implant can handle. The average TKR lasts about 15 years. Older adults who have a TKR usually die before the knee wears out. The average life of the UKA is unknown. Mid- and long-term results of UKA are slowly trickling into the published literature.

Patients with UKA report their motion and feeling with the implant are more like a normal joint. Computer analysis shows knee joint biomechanics with a UKA are closer to a normal knee compared to the biomechanics provided by a TKR. That’s because the cruciate ligaments inside the joint are not cut or removed with a UKA (but they often are with a TKR).

At age 62, you may be a good candidate for a UKA. With increasing life expectancy for many adults, the UKA may give you added years of quality knee function. Then if you need to convert to a TKR later, it may be an available option.