2015 ISAKOS Biennial Congress ePoster #1427

Patient Specific Guide Versus CT-Free Navigation System in Total Knee Arthroplasty

Taisei Kawamoto, MD, PhD, Tokyo JAPAN
Satoshi Iida, MD, Matsudo JAPAN
Manato Horii, MD, Chiba City JAPAN
4005 Kamihongo, Matsudo, Chiba, JAPAN

FDA Status Cleared

Summary: Background: Recently, patient specific guide(PSG) in total knee arthroplasty have been introduced , in which preoperative 3-dementional imaging is used to manufacture disposable cutting guide specific to a patient’s anatomy. The aim of this study is to evaluate clinical results and quantify the coronal plane alignment between a group of patients who underwent TKA using PSG versus CT-free navigat

Abstract:

Background

Variability in component alignment continues to be a major in total knee arthroplasty(TKA). In the long term,coronal plane malalignment has been associated with an increased risk of loosening, insatability, and wear. Recently, patient specific guide(PSG) in total knee arthroplasty have been introduced , in which preoperative 3-dementional imaging is used to manufacture disposable cutting guide specific to a patient’s anatomy. The goal of patient specific guide are to improve the accuracy of post operative alignment and eliminate outlier cases. The aim of this study is to evaluate clinical results and quantify the coronal plane alignment between a group of patients who underwent TKA using PSG versus CT-free navigation system.
Patients and Method: An unselected consecutive series of ninety-two patients undergoing primary TKA using the same cruciate retaining cemented total knee system between April 2010 and September 2013 were studied. Patients were included only if they were deemed to be candidates for a Cruciate retaining TKA. Patients were excluded if they had a flexion contracture greater than 40°,or severe valgus or varus deformity. Fifty-two knees was operated a TKA with CT-free navigation system. Subsequently forty knees was received a TKA using CT-based patient specific guide(SignatureTM). Postoperatively standing AP hip-to-ankle radiographs were obtained, from which the lower extremity mechanical axis, component angle were measured. The alignment goals were a neutral mechanical axis defined as a hip-to-ankle angle of 0°with the femoral and tibial components aligned perpendicular to the mechanical axis. The total operating time were quantified utilising an operating room database. The total operating time between TKAs performed with CT-free navigation system and those performed with patient specific guides was compared in each group. All patients postoperatively was evaluated of clinical results the Japan Orthopedics Association(JOA) Knee scores.Postoperative blood loss volume were also measured.

Results

The mechanical axis angle in PSG group was 2.2°,while the CT-free navigation system group was 2.3°and there was no statistical significance.The number of outliers for mechanical axis angle was virtually identical between patient specific guide group 32.5% and the standard navigation group 23.1%.The tibial components angle in PSG group was 88.8° , while the navigation group was 89.6° ,between the two groups there was statistical significance. The operative time in PSG was 113.9minutes and significantly less compared to the time of navigation group 150.4 minutes. The JOA Knee score of navigation group was 83.9 points, and the score of PSG group was 84.6 points. There was no statistical significance between the two groups on the clinical score. The blood loss volume of between the two group was no different substantially. Conclusion: patient specific guide improved operative time in TKA, this study demonstrates patient specific guide to obtain same angle of overall mechanical axis angle , but did not demonstrate tibial component alignment accuracy as a navigation technique.