The controversy of patellar resurfacing in total knee arthroplasty: Ibisne in medio tutissimus?

Early arthroplasty designs were associated with a high level of anterior knee pain as they failed to cater for the patello-femoral joint. Patellar resurfacing was heralded as the saviour safeguarding patient satisfaction and success but opinion on its necessity has since deeply divided the scientific community and has become synonymous to topics of religion or politics. Opponents of resurfacing contend that the native patella provides better patellar tracking, improved clinical function, and avoids implant-related complications, whilst proponents argue that patients have less pain, are overall more satisfied, and avert the need for secondary resurfacing. The question remains whether complications associated with patellar resurfacing including those arising from future component revision outweigh the somewhat increased incidence of anterior knee pain recorded in unresurfaced patients. The current scientific literature, which is often affected by methodological limitations and observer bias, remains confusing as it provides evidence in support of both sides of the argument, whilst blinded satisfaction studies comparing resurfaced and non-resurfaced knees generally reveal equivalent results. Even national arthroplasty register data show wide variations in the proportion of patellar resurfacing between countries that cannot be explained by cultural differences alone. Advocates who always resurface or never resurface indiscriminately expose the patella to a random choice. Selective resurfacing offers a compromise by providing a decision algorithm based on a propensity for improved clinical success, whilst avoiding potential complications associated with unnecessary resurfacing. Evidence regarding the validity of selection criteria, however, is missing, and the decision when to resurface is often based on intuitive reasoning. Our lack of understanding why, irrespective of pre-operative symptoms and patellar resurfacing, some patients may suffer pain following TKA and others may not have so far stifled our efforts to make the strategy of selective resurfacing succeed. We should hence devote our efforts in defining predictive criteria and indicators that will enable us to reliably identify those individuals who might benefit from a resurfacing procedure. Level of evidence V

Comparison of static and mobile antibiotic-impregnated cement spacers for the treatment of infected total knee arthroplasty

Infection after total knee arthroplasty (TKA) is a devastating complication, and two-stage reimplantation has evolved as an effective treatment option. This study was undertaken to compare the clinical results and radiological changes associated with static or mobile cement spacer placement for the treatment of infected TKA. Between July 2000 and February 2007, 36 consecutive patients were treated by two-stage reimplantation using antibiotic-impregnated cement spacers (AICS) for infected TKAs. Static spacers were used in 20 knees and mobile spacers in 16 knees. Clinical outcomes included success rates of TKR revisions, ranges of motion (ROM), and Hospital for Special Surgery knee scores (HSS), pain and function scores of the Knee Society (KS), joint exposure methods, and bone loss. In this study, mobile spacers provided better ranges of motion and functional knee scores without concomitant increases in infection rate and bone loss in the initial and mid-term periods