Reliability of Templating with Patient-Specific Instrumentation in Total Knee Arthroplasty

Abstract

Magnetic resonance imaging (MRI) or computed tomography-based patient-specific instrumentation (PSI) may allow for reliable alignment and fewer outliers when compared with conventionally instrumented total knee arthroplasty (TKA). However, some authors have suggested that frequent intraoperative surgeon-directed changes may still be required. This study evaluated the accuracy of PSI to predict component sizing and alignment during TKA. A total of 84 patients (89 knees) who underwent a TKA using a PSI system were evaluated. An MRI-based preoperative plan of every knee was provided and approved by the surgeons. This demonstrated the proposed prosthetic component alignment, as well as the femoral, tibial, and bearing insert component size and position. Intraoperative changes to these components were prospectively recorded and compared with the computerized preoperative plan. Major changes were defined as any changes in femoral or tibial resection, size, and position of the components. Minor changes were defined as any change in the size of the polyethylene bearing insert. The preoperative plan was able to correctly predict the size of the implanted tibial and femoral component in 93 and 95.5% of the cases, respectively. Thirteen major intraoperative changes were made. In one knee, the proposed femoral resection was not acceptable (because of the presence of significant amount of osteophytes) and was abandoned in favor of a manual extramedullary guide. In another patient, the proposed femoral and tibial components were upsized. In two other patients, the femoral components were downsized, in four patients, the tibial components were downsized, and in another patient, it was upsized. There were also 16 minor changes, which included 2-mm upsizing of the polyethylene liner in 13 knees and 4-mm upsizing in 3 knees. Surgical experience is necessary to recognize improper component size, incorrect surgical resection, or nonideal alignment when performing TKA using PSI. The authors believe that the design and manufacture of PSI combined with a comprehensive templating resulted in excellent intraoperative concordance of the preoperative plan at the default settings with minimal changes.

No Evidence of Superiority in Reducing Outliers of Component Alignment for Patient‐specific Instrumentation for Total Knee Arthroplasty: a Systematic Review

“…Issa et al . reported 29 intraoperative changes in 89 primary TKAs using PSI technology. The above factors may account for the discrepancy between the theoretical advantages and the reality.…”

Systematic Review of Patient-specific Instrumentation in Total Knee Arthroplasty: New but Not Improved

“…Finally, another Level II study demonstrated that cuts achieved with PSI did not correspond to the preoperative plan when checked intraoperatively with computer-assisted navigation tools [10]. Only a single Level II study concluded that minimal changes were required to the preoperative plan laid out by the PSI manufacturer [15]. The consensus of the two studies that addressed this question was that the use of patient-specific cutting blocks did not confer any functional gains when compared with traditional instrumentation.…”

Three-Dimensional Imaging and Templating Improve Glenoid Implant Positioning

“…Total knee arthroplasty [11][12][13][14][15][16][17][18] , total hip arthroplasty [19][20][21] , hip resurfacing 22 , pelvic and acetabular procedures [23][24][25] , and spinal deformities 26,27 have all utilized patient-specific instrument technology with varying degrees of success. Recently, patientspecific instrumentation was found to improve glenoid component placement in both the version and inclination planes when compared with standard two-dimensional surgical planning 28,29 .…”