Patient Specific Instrumentation: Transfusions and Complications
Moderate evidence supports not using patient specific instrumentation compared to conventional instrumentation for total knee arthroplasty (TKA) because there is no difference in transfusions or complications.

Rationale
Two high quality studies (Pfitzner 2014 and Pietsch 2013) demonstrated no difference in knee society and visual analog pain scores between patient specific cutting guides and conventional instrumentation. Both studies also found no difference in knee society function score and one study (Pfitzner 2014) additionally found no difference in the overall WOMAC score. There was heterogeneity in outcomes regarding perioperative blood loss with Pietsch 2013 demonstrating a clinically significant difference in perioperative blood loss, however, no impact in the drop in hgb and need for transfusion. This indicates that while there is some improvement in blood loss in patients who receive patient specific instrumentation there was no significant clinical impact when compared to conventional instrumentation. Three moderate quality studies and one low quality study found similar results with no significant difference between both treatment groups.

There was no evidence to demonstrate a clinically relevant difference in surgical time or shorter length of stay when comparing both groups. One moderate quality study (Boonen 2013) found no difference in hospital length of stay between both groups.

The work group recognizes that there are scenarios where patient specific instrumentation theoretically could be considered but the evidence is insufficient to make a recommendation.