What question did this study set out to answer?

This research aims to evaluate the effectiveness of a 3D navigation technique for achieving patient-specific alignment in total knee arthroplasty.

March 25, 2026Open Access

Patient-Specific Restoration of Constitutional Alignment Within Predefined Safety Boundaries Using Three-Dimensional Navigation in Primary Total Knee Arthroplasty: One-Year Clinical and Radiographic Outcomes

Key Points

This research aims to evaluate the effectiveness of a 3D navigation technique for achieving patient-specific alignment in total knee arthroplasty.
Retrospective analysis of 185 total knee arthroplasties performed on 171 patients
Implementation of patient-specific restoration of alignment with a 3D navigation system
Assessment of clinical outcomes using various scoring systems including KSS, FJS-12, and UCLA Activity Scale
87.6% of patients reported satisfaction with their TKA
Significant improvements in KSS across all subcategories (p < 0.001)
FJS-12 scores increased significantly from 32.5 to 79.3 (p < 0.001)
UCLA Activity Score rose from 4.9 preoperatively to 6.6 postoperatively (p < 0.001)
97.7% of femoral mechanical angle and 90.2% of tibial mechanical angle cuts were within ± 1° of planned angles

Abstract

Background/Objectives: This study investigates a surgical concept that restores constitutional bony alignment within predefined safety boundaries in primary total knee arthroplasty (TKA) using modern 3D navigation. The technique combines a standard knee implant with advanced navigation technology to achieve patient-specific alignment and recreate native joint mechanics. One-year outcome was evaluated to assess first clinical results. Methods: In this retrospective study, a consecutive series of 185 TKAs (171 patients) was analyzed. All patients underwent patient-specific restoration of constitutional alignment within predefined safety boundaries using a 3D navigation system and a standard knee arthroplasty implant. The clinical outcomes were assessed using the 2011 Knee Society Score (KSS), the Forgotten Joint Score (FJS-12), the UCLA Activity Scale, and a five-step Likert scale to evaluate satisfaction. Results: In a total of 87.6% of cases, the patients reported being either satisfied or very satisfied with their TKA. No patients reported strong dissatisfaction. The KSS demonstrated significant improvements in all subcategories (all p < 0.001). The FJS-12 increased significantly from a preoperative average of 32.5 points to 79.3 points postoperatively (p < 0.001). The mean UCLA activity score rose from 4.9 preoperatively to 6.6 postoperatively (p < 0.001). In 97.7% and 90.2% of cases, the femoral mechanical angle (FMA) and tibial mechanical angle (TMA) bone cuts were within ± 1° of the planned angles. A strong correlation was observed between the planned and verified bone cuts for the FMA (ρ = 0.939) and the TMA (ρ = 0.875). Conclusions: Patient-specific restoration of constitutional alignment within predefined safety boundaries in primary TKA using modern 3D navigation is a promising strategy for personalized joint reconstruction using a standard knee arthroplasty implant. It combines precision and reproducibility with high patient satisfaction by respecting each patient’s constitutional alignment.

Patient-Specific Restoration of Constitutional Alignment Within Predefined Safety Boundaries Using Three-Dimensional Navigation in Primary Total Knee Arthroplasty: One-Year Clinical and Radiographic Outcomes

Key Points

Abstract

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