Accuracy of Individualized Custom Tibial Cutting Guides in UKA

HSS Journal Online First Article

Thomas J. Heyse, MD, PhD

Department of Orthopaedics and Rheumatology, University Hospital Marburg, Germany

Joseph Lipman, MS

Department of Biomechanics, Hospital for Special Surgery

Carl W. Imhauser, PhD

Department of Biomechanics, Hospital for Special Surgery

Scott M. Tucker, MS

Department of Biomechanics, Hospital for Special Surgery

Yogesh Rajek

Department of Biomechanics, Hospital for Special Surgery

Geoffrey H. Westrich, MD
Geoffrey H. Westrich, MD

Attending Orthopedic Surgeon, Hospital for Special Surgery
Research Director of Adult Reconstruction and Joint Replacement Service, Hospital for Special Surgery


Component malposition is one of the major reasons for early failure of unicompartmental knee arthroplasty (UKA).

It was investigated how reproducibly patient-specific instrumentation (PSI) achieved preoperatively planned placement of the tibial component in UKA specifically assessing coronal alignment, slope and flexion of the components and axial rotation.

Patients and Methods
Based on computer tomography models of ten cadaver legs, PSI jigs were generated to guide cuts perpendicular to the tibial axis in the coronal and sagittal planes and in neutral axial rotation. Deviation ≥ 3° from the designed orientation in a postoperative CT was defined as outside the range of acceptable alignment.

Mean coronal alignment was 0.4 ± 3.2° varus with two outliers. Mean slope was 2.8 ± 3.9° with six components in excessive flexion. It was noted that the implants were put in a mean of 1.7 ± 8.0° of external rotation with seven outliers.

PSI helped achieve the planned coronal orientation of the component. The guides were less accurate in setting optimal tray rotation and slope.

This article was published online September 2014.
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About the HSS Journal

HSS Journal, an academic peer-reviewed journal published three times a year, February, July and October. The Journal accepts and publishes peer reviewed articles from around the world that contribute to the advancement of the knowledge of musculoskeletal diseases and disorders.


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