Effects of patient-specific positioning guides (PSPGs) vs. conventional instrumentation on patient-reported outcome in total knee arthroplasty: secondary analysis of a randomized controlled trial after 5 years.

Background and purpose: The use of patient-specific positioning guides (PSPGs) in total knee arthroplasty (TKA) has been advocated as a means of improving patient outcomes, but the reception of PSPGs has been mixed. The aim of our study was to compare patient-reported outcomes (KOOS, NRS-11, EQ-5D-3L, EQ-VAS) after TKA using PSPG with conventional instrumentation (CI) to determine whether there is a discernible clinical benefit to using PSPGs.

Patients and methods: This multicenter randomized controlled trial (RCT) followed 77 patients who were randomly assigned to 1 of 2 cohorts between September 2011 and January 2014-one receiving TKA with PSPGs (from Materialise NV) and one receiving TKA with CI-with each cohort followed up until 5 years after the operation. The Vanguard Cruciate Retaining Total Knee System and Refobacin Bone Cement R were used in all operations. KOOS was evaluated using confidence intervals, with differences of less than 10 KOOS units between the cohorts interpreted as indicating the absence of a clinically meaningful difference.

Results: No significant differences were found in any of the measured clinical outcomes-KOOS, NRS-11, EQ-5D-3L, EQ-VAS, range of motion, or radiolucent lines scoring-between the cohort operated on using PSPG and the cohort operated on using CI after 5 years of follow-up.

Conclusion: There was no statistically significant effect of PSPGs on patient-reported outcomes or range of motion in TKA.