Minimally invasive surgical technique for unicondylar knee arthroplasty.

Between August 1992 and December 1996, more than 700 unicondylar knee arthroplasty (UKA) procedures were done by the senior author (JA.R.), using well-defined patient selection criteria, which is paramount to the outcome of the procedure. The UKA procedure described is done through a smaller incision than that required for total knee arthroplasty (TKA) (3 inches versus 8 inches), thus minimizing blood loss (less than 200 mL), avoiding normal tissue sacrifice (opposite compartment, patellar bone, and cruciate ligaments), and decreasing morbidity (no patellofemoral disruption). The UKA costs less because it is done as an outpatient procedure in 80% of cases; since postoperative physical therapy is minimal or unnecessary, recovery time is shorter (90% independent function at 2 weeks after operation). Whereas TKA can have universal application, UKA is patient specific and cannot replace TKA in all circumstances. Likewise, the techniques for TKA and UKA are not interchangeable. However, with the use of well-defined patient populations and surgical techniques, the intermediate results of UKA have paralleled reported outcomes of TKA.