GENERAL INFORMATION

Current scholarly publications conclude that the advantages of the UKA outweigh those of a Total Knee Arthroplasty (TKA) if done for the correct indications using a suitable surgical technique.¹

UKA could be used in at least 49-60% of operations where the TKA was used2,3.

It is neither warranted nor suitable to do a TKA for every patient that presents with a focal Grade 4 Kellgren and Lawrence4 Osteoarthritis (OA) lesion (bone-on-bone degeneration). This is despite the higher incidence of complications of the UKA attributed to the inexperienced surgeon4.

The knee must be evaluated as suitable for a UKA, as treating every knee with a TKA is not acceptable due to the functional deficit created by the loss of the Anterior Cruciate Ligament (ACL) and can be functional for more than 20 years (93% survival over 20 years)5.

The thought of dealing with every knee without identifying the specific problem, and treating it using a TKA as the only solution, equates to the need for a heart transplant when you have a heart attack (a stent and bypass should be considered) with retention of the normal anatomy, especially the ACL6.

The result achieved in the long term in the specialised centres where the UKA procedure is often done achieves similar results in survival over 10, 15, and 20 years with better functional results (range of motion and activity level). The obvious advantages are discussed below with the primary goal being the preservation of normal knee anatomy and function. This allows the patient “normal” knee function with the ability to proceed to a TKA with failure of the UKA.

The TKA should be used for the correct indications and as a salvage procedure of last resort.

UKA specific information

The knee presents in a phase of degeneration with the constitutional alignment causing a specific wear pattern with pain, function-loss and deformity.

The timing and election of the suitable arthroplasty is evaluated with the different options of treatment at the different stages of presentation.

When these lesions are focal areas of degeneration, they can be effectively treated with smaller procedures like the UKA with the various advantages as discussed below.

> Retention of all the ligaments > Preservation of most of the anatomy (less destruction of bone) > Minimal knee incision with retention of normal proprioception > Effectively resurfacing a single compartment and restoring balance and function to the joint > UKA is functionally similar to a normal knee (far superior to a TKA). It is proven that 14-25% of TKA patients are dissatisfied with their prosthesis. The younger the patient, the more dissatisfaction (due to loss of function) > Less blood loss > Less immediate cost and overall cost to the health system > Less nursing and rehabilitation required > Improved quality of function e.g. stair-climbing and sports activities > Earlier independent ambulation, driving and earlier return to work > Complications are less grave and easier to deal with e.g. deep vein thrombosis (DVT), catastrophic embolism, death, amputation and infection > This solution allows for further treatment if the patient outlives the implant with e.g. a primary TKA > In the TKA cohort; 15% of the treated knees are painful for at least 2 years and 6% suffer from permanent pain; UKA has a 0.7% incidence of permanent pain > The need for a revision of the contralateral Tibiofemoral joint OA is rare if the indications are correct (less than 5% over 20 years). Even with full thickness OA present on the Patellofemoral joint, it is seldom an indication for a TKA > UKA is currently done in the USA and Europe as a day procedure if the environment and support allows it

for more info

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