Handheld Navigation Device and Patient-Specific Cutting Guides Result in Similar Coronal Alignment for Primary Total Knee Arthroplasty: a Retrospective Matched Cohort Study

Abstract

Background: Proper alignment of total knee arthroplasty (TKA) is essential for TKA function and may reduce the risk of aseptic failure. Technologies that prevent malalignment may reduce the risk of revision surgery. Questions/Purposes: The purpose of this study was to compare two competing TKA systems that purport improved alignment: patient-specific instrumentation (PSI), and a handheld portable navigation device (NAV). Methods: After IRB approval, 49 consecutive PSI TKAs (40 patients) were matched based on preoperative characteristics to 49 NAV TKAs (40 patients) performed by a single surgeon. A blinded observer measured alignment on digital radiographs. Operating room records were reviewed for procedure times. Two-tailed paired sample t tests and McNemar's test were used as appropriate. Alpha level was 0.05 for all tests. Results: Preoperative cohort characteristics were not different. Mean postoperative long-leg mechanical alignment was within ±1°of neutral for both groups, although statistically different (p = 0.026). There were no other significant differences in coronal alignment. PSI exhibited significantly greater posterior tibial slope (4.4°) compared to NAV (2.7°) (p = 0.004); PSI resulted in significantly more outliers (>6°; p = 0.004). Procedure time for unilateral TKAs was lower for PSI (74.4 min) compared to that for NAV (80.6 min; p = 0.023). Conclusion: NAV and PSI technologies provided excellent coronal plane alignment. NAV was better for sagittal tibial slope, while PSI procedure times were shorter for unilateral TKA. The impact of these technologies on patientreported outcomes and TKA survivorship is controversial and should be the focus of future research.

The Impact of Surgeon Volume and Training Status on Implant Alignment in Total Knee Arthroplasty

“…While custom cutting guides offer theoretical advantages, the majority of mid-to-long-term studies assessing their efficacy have demonstrated nonsuperiority [20][21][22][23][24][25][26] . Although the true value and cost-effectiveness of robotic technology have been debated, the use of robotic-arm assistance has demonstrated superiority to patient-specific instrumentation 27 and has shown the ability to improve TKA alignment in multiple studies 19,[28][29][30][31][32] . The findings of the current study, especially if alignment outlier status is linked to increases in implant failure in follow-up studies, may justify the increased use of these technologies in the future.…”

“…As a result of the link between implant alignment outliers and early implant failure, efforts have been made to optimize alignment with the use of robotic navigation and patient-specific instrumentation [19][20][21][22][23][24][25][26][27][28][29][30][31][32] . However, little work has been conducted to identify the primary surgeon-specific factors that drive these outliers in order to understand the optimal patient populations in which to utilize this expensive technology.…”

Handheld, accelerometer‐based navigation versus conventional instrumentation in total knee arthroplasty: a meta‐analysis

“…1). In addition, five studies 25,27,[37][38][39] were identified that compared ABN to CAS or PSI that formed part of a descriptive review.…”

“…After exclusion, two studies met final inclusion criteria. 27,37 Kawaguchi et al 27 retrospectively compared 34 ABN TKAs using KneeAlign2 for the distal femoral resection with 32 PSI TKAs (Biomet, Warsaw, IN, USA). They found significantly fewer outliers >3 in the HKA (9.1% versus 22.5%), CFA (0% versus 12.9%) and SFA (9% versus 37.5%) favouring ABN.…”

“…Steinhaus et al 37 compared 49 ABN TKAs using KneeAlign2 for the tibia and femur resections with 49 PSI TKAs (VISIONAIRE, Smith and Nephew, Memphis, TN, USA) in a retrospective matched cohort. They found the mean postoperative HKA was within AE1 of neutral for both groups and no significant differences in coronal alignment or outliers >3 0 .…”