Nattapol Tammachote, MD, Thammasat University, Bangkok, Thailand, presented data from a study comparing the use of a customized cutting block (CCB) with conventional instrumentation (CI) in patients undergoing total knee arthroplasty (TKA). The results demonstrated that CCBs save surgical time, thereby improving operating theater efficiency.

CCBs are designed to improve alignment accuracy in TKA, and this technology provides advantages over the use of CI, including a lack of reliance on instrumentation of the intramedullary femoral canal. Nevertheless, it does carry some disadvantages, such as the need for preoperative scheduling for imaging studies and preoperative planning time by the surgeon, as well as the delay in obtaining the CCB. Yet, although the ultimate goal of using this patient-specific instrumentation is to allow more efficient use of operative resources, increase component alignment accuracy, and thereby improve patient outcomes, well-designed studies to confirm its efficacy are lacking.

Prof Tammachote and colleagues therefore conducted a randomized controlled trial to compare the use of a CCB with CI in TKA. The study was performed from 2012 to 2014 at a single center, and it enrolled 129 patients. Inclusion criteria included patients aged between 50 and 85 years with osteoarthritis of the knee who were willing to wait 4 to 6 weeks for surgery and had no contraindication for preoperative magnetic resonance imaging. Patients were excluded if they had undergone previous ipsilateral hip, knee, or ankle replacement or had metallic hardware around the knee or deformity of the tibia or femur.

A total of 108 patients were ultimately included in the study and were randomized to undergo TKA using either CCB (n = 54) or CI (n = 54). All surgeries were performed by the same experienced surgeon, using the standard medial parapatellar approach. Patients were followed for up to 3 months, and primary outcome measurements included limb and prosthesis alignment, operative time, and hemodynamic evaluations.

According to Prof Tammachote, the average operative time was 11 minutes shorter in the CCB group (93 vs 104 minutes; P < .0001; Table 1).

However, there was no significant difference in the mean hip-knee-ankle angle (179.4° vs 179.1°; P = .55) between the CCB and CI groups. Hemodynamic evaluations were also similar between the groups, including the average total blood loss postsurgery (466 vs 514 mL; P = .21) and reduction in hemoglobin concentration at 24 hours postsurgery (2.2 vs 2.8 g/dL; P = .42).

The results of this study demonstrate that use of the CCB for TKA reduces surgical time compared with CI, thereby improving operating theater efficiency. CCB use is also as accurate as CI when the procedure is performed by an experienced surgeon, and there is no difference in hemodynamic outcomes, concluded Prof Tammachote.