The Resurfacing of a Pathological Knee Compartment

Painfull loss of function and mobility due to a pathological loss of cartilage in the knee joint has been routinely addressed by orthopaedic surgeons with total knee replacements. (TKR)

The adage of the TKR being such a successful and long lasting procedure and therefore it should be the gold standard of acre is not acceptable in an aging, active population with demands on functionality and longevity far better than their parents.

Modern medicine dictates lesser invasive, longer lasting prosthetic devices due to this aging and active world population.

This is in part due to good and sensible medical care with quality of life dictating the development of better procedures.

The partial knee replacement, whether an unicondylar or patellofemoral replacement, was devised due to the necessity of addressing the pathological part of the knee and not as a salvage procedure as with the total knee replacement.

The knee is a tricompartmental joint (medial, lateral and patellofemoral) and each joint area works independently as well as in concert to obtain maximum functionality.
The most common area of wear is the medial compartment which takes 75% of the load bearing pressure.

Devices that were developed over the last 50 years enhance life span of the knee especially with degenerative osteoarthritis whether it is due to trauma or wear.

We will restrict the discussion to medial and lateral compartment replacements.
The success story of the TKR did restricts the development of the partial replacement but with the demands of the modern life interst in the resurfacing of the knee joint has increased.

Unicompartmental osteoarthritis does not inevitably spread to the rest of the knee (2) and therefore it is safe to resurface part of the knee if it is affected.

The collective surgical experience in the literature is increasing but as it is seen to be a more complicated procedure with higher demands than a TKR it has had its skeptics. Not least the older generation of surgeon who has had great success with the TKR.

The Unicompartmental Knee Replacement (UKR) is now a proven and successful procedure but requires good surgical technique and sound judgment as to the right indications, which will be discussed.

The biomechanics of the knee are more completely restored with a normal gait and especially activities like climbing stairs.(3) (4)

According to the Swedish Knee Arthroplasty Register (SKAR) 2004 (5) report the number of serious complications such as infection, arthrodesis and amputations are less. Revision surgery with UKR is usually easier than with a TKR and the results of such revisions are as good as a primary TKR. (6)

Blood transfusion is not required and post-operative recovery is quicker. (7)

The kinematics of the knee is restored to the same level as a normal knee with a mobile UKR and not with a TRK. (8) (9)