ISSN 2380-2995 (Online)
ISSN 2380-2987 (Print)


Ronald W. Lindsey, MD
Zbigniew Gugala, MD, PhD


Utility and Precision of CT-Based Patient-Specific Instrumentation for Total Knee Arthroplasty

Tyler D. Goldberg, MD[1][2]; Andrea M. Torres, BS[1]; Jared Bush, PA-C[1]; Sanjib Basu, PhD[3]

[1] Texas Orthopedics, Sports and Rehabilitation Associates; Austin, TX, USA
[2] Dell Medical School, The University of Texas at Austin, TX, USA
[3] Northern Illinois University; DeKalb, IL, USA

Corresponding Author:
Tyler D. Goldberg, MD
Texas Orthopedics, Sports and Rehabilitation Associates
4700 Seton Center Parkway
Suite 200
Austin, TX 78759, USA



Introduction:  Patient-specific instrumentation has been introduced to total knee arthroplasty (TKA). This paper reports on the clinical, operative, and radiographic outcomes of CT-based TKAs.

Methods: 100 consecutive TKAs (94 patients) using CT-based patient-specific instrumentation (PSI) were performed. The planned preoperative versus the actual bony resections we compared. Pre- and postoperative Knee Society Score (KSS), range of motion (ROM), and complications were analyzed. Long-leg standing radiographs were obtained to assess alignment. Additionally, 10 randomly selected TKA patients received postoperative CT imaging for comparison.

Results: Average patient follow up was 3.9 years. At 1 year, mean KSS increased from 44.3 to 81.8, whereas KSS Functional Score improved from 59.1 to 81.8. Mean ROM was 110.5 preoperatively and 111.3 postoperatively. Two patients had a postoperative infection requiring surgery. The actual bony resections achieved during surgery strongly correlated with the preoperatively planned resections of all 6 bone fragments measured (p<0.001). Average postoperative alignment measured on plain radiographs was 179.36°. The average postoperative hip-knee-ankle measured by CT was 179.9°±1.31°. When comparing the X-ray and CT measurements, we found only 0.09° average difference preoperatively and 0.2° postoperatively (p<0.001).

Discussion: The present study demonstrates improvement in patient function and accurate and reliable postoperative alignment, thereby supporting the use of CT-based patient-specific instrumentation in TKA. Level of Evidence:

Level of Evidence: II; Prospective case series.

Keywords: Total knee arthroplasty; Patient-specific instrumentation; Arthroplasty outcomes.