Are patient-specific cutting blocks cost-effective for total knee arthroplasty?

Abstract

Background: Using patient-specific cutting blocks for TKA increases the cost to the hospital for these procedures, but it has been proposed they may reduce operative times and improve implant alignment, which could reduce the need for revision surgery.

Questions/purposes: We compared TKAs performed with patient-specific cutting blocks with those performed with traditional instrumentation to determine whether there was improved operating room time management and component coronal alignment to support use of this technology.

Methods: We retrospectively reviewed 57 patients undergoing primary TKAs using patient-specific custom cutting blocks for osteoarthritis and compared them with 57 matched patients undergoing TKAs with traditional instrumentation during the same period (January 2009 to September 2010). At baseline, the groups were comparable with respect to age, sex, and BMI. We collected data on operative time (total in-room time and tourniquet time) and measured component alignment on plain radiographs.

Results: On average, TKAs performed with patient-specific instrumentation had similar tourniquet times (61.0 versus 56.2 minutes) but patients were in the operating room 12.1 minutes less (137.2 versus 125.1 minutes) than those in the standard instrumentation group. We observed no difference in the femorotibial angle in the coronal plane between the two groups.

Conclusions: Patient-specific instrumentation for TKA shows slight improvement in operating room time management but none in component alignment postoperatively. Therefore, routine use of this new technology may not be cost-effective in its current form.

Level of evidence: Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Fig. 1

A CT scout image shows the lower-extremity alignment with a field of view from the hip to ankle used to make measurements for this study.

Fig. 2

A CT scout image magnified at the knee shows the two augment holes (arrows) on the posterior condyles of the femoral component used to help standardize the extremity rotation before making measurements by ensuring the holes are visible on either side of the anterior flange of the femoral component.