Abstract
INTRODUCTION
Despite that computer-assisted orthopaedic surgery (CAOS) has been shown to offer increased accuracy to the bony resections compared to the conventional techniques [1], previous studies of CAOS have mostly focused on alignment outcomes based on a small number of patients [1]. Although several recent meta-analyses on the CAOS outcomes have been reported [2], these analyses did not differentiate between systems, while system-dependency has been reported to influence alignment parameters [3]. To date, no study has benchmarked a specific CAOS system based on a large number of clinical cases. The purpose of this study is to assess the accuracy and precision of bony resection in more than 4000 cases using a specific contemporary CAOS system.
Materials and Methods
Technical logs of 4292 TKAs performed between October 2012 and January 2016 using a contemporary CAOS system (ExactechGPS, Blue-Ortho, Grenoble, FR) were analyzed. The analyses were performed on: 1) planned resection, defined by the surgeon prior to the bone cuts. These parameters serve as inputs for the CAOS guidance; and 2) Checked resection, defined as digitalization of the actual resection surfaces by manually pressing an instrumented checker onto the bony cuts. Deviations in alignment and resection depths (on the referenced side) between planned and checked resections were calculated in coronal and sagittal planes for both tibia and femur (planned vs checked).
Results
Summary and distribution of the deviations in resection parameters are presented in Table 1 and Fig 1. On average, the alignment deviations were near 0°, and the deviations in resection depths were less than 0.15mm. Small standard deviations were observed.
Discussion
This study demonstrated that the CAOS system investigated can offer accurate and precise intra-operative guidance to the surgeon in achieving his/her surgical goals. TKA performed using conventional instruments is reported to achieve satisfactory lower limb alignment (within ±3° of alignment deviation) in only 70–80% of the cases [2,4], which may contribute to 20% of patients being dissatisfied with the results of surgery [5]. This study reviewed a large number of cases spanning the application history of the specific CAOS system, providing a complete clinically relevant evaluation of its accuracy and precision in terms of bony resection. The results confirmed that the system investigated can be used with confidence that the surgical goals can be achieved with accuracy and reliability.
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