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Due to the irregular shape of patella and difficulty in identifying its bony landmarks, it can be a challenge for surgeons to accurately and symmetrically perform patellar resurfacing. Three-dimensional (3D) models of 20 patellae were generated from computed tomographic images. Using a computer-assisted preoperative planning technique, customized template designs were developed to guide patellar resurfacing. The patellar models and corresponding templates were produced through rapid prototyping. The accuracy of this technique was assessed after applying the templates on patellar models and cadaver specimens, respectively. Using preoperative planning and predesigned templates, a significant improvement in symmetric patellar resurfacing, with a mean angle of 1.21° mediolateral (ML) obliquity and 1.95° superoinferior (SI) obliquity, was observed compared with the conventional sawguide technique (mean angle of ML and SI was 4.13°, 4.95°, respectively). Additionally, the use of customized templates reproduced the desired preplanned patellar resection. Preoperative planning with 3D imaging and customized templates improved the accuracy of patellar resurfacing in terms of the obliquity and thickness., Clinical Relevance: A novel customized template designed for patellar resectioning will benefit surgeons in performing patellar resurfacing. This technique will provide accurate patellar resurfacing in clinical practice. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1798-1803, 2016., (© 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.)

Purpose: The present study was designed to compare the dimensions of the anterior femoral condyle with those of the anterior component flange using intraoperative morphological data., Methods: Overall, 1227 knees in 962 patients were included in this study. The height of the anterior lateral/medial condylar height (ALCH/AMCH) was measured and compared between men and women. These morphological data were compared with the dimensions of the chosen component for each patient. The lateral/medial anterior femoral offset was calculated, and the over-/understuffing rates were compared between men and women., Results: The median ALCH in men was 8.5 mm (6.5, 10.0 mm) versus 7.0 mm (6.0, 9.0 mm) in women. The median AMCH in men was 4.0 mm (2.5, 6.0 mm) versus 3.5 mm (2.5, 6.0 mm) in women. There was a significant difference between the genders with respect to ALCH (p < 0.05). When the dimensions of the component were compared with those of the native knee, the anterior lateral flange height was smaller than the native knees (1.3 mm in male, 0.7 mm in female), but the anterior medial flange height was larger than the corresponding condyle (1.8 mm in male, 1.8 mm in female). A significant difference was observed between the genders with respect to the ideal fit rate of ALCH (p < 0.01)., Conclusion: The results demonstrate that gender differences exist in the anterior lateral condyles of knees. The anterior flange of component is not designed to precisely reproduce normal trochlear anatomy., Level of Evidence: II.

Purpose: Patellofemoral syndrome is still a common complication after total knee arthroplasty (TKA). However, the effects of specific surgical approaches on patellar tracking and alignment remain incompletely understood. In this study, we compared patellar alignment in patients who underwent TKA via three different techniques., Methods: A total of 96 patients who completed a minimum follow-up of five years were involved in three groups: 30 patients were treated with the traditional medial parapatellar approach (MPP group), 35 patients were treated with the mini-medial parapatellar approach (MMP group) and 31 were treated with a quadriceps-sparing approach (QS group). Radiographic data for patellar alignment and clinical results were compared., Results: Patellar tilt and patellar displacement at the final follow-up evaluation differed significantly among the three groups [P < 0.01, analysis of variance (ANOVA)]. The MMP and QS groups exhibited more proper patellar alignment than the MPP group. The clinical results did not differ significantly among the groups (P > 0.05, ANOVA). In addition, there were no correlations between postoperative patellar alignment and clinical scores., Conclusions: The results of this study indicate that TKA performed using minimally invasive approaches yields superior patellar alignment compared to the traditional MPP approach.

Background: Although the early clinical outcomes of total knee arthroplasty (TKA) using minimally invasive surgery techniques have been widely described, data on the mid- to long-term outcomes are limited. We designed a retrospective study to compare the two most common TKA techniques - The modified quadriceps-sparing (m-QS) approach and the mini-medial parapatellar (MMP) approach - In terms of the clinical and radiographic parameters, over a minimum follow-up period of 5 years., Methods: The m-QS approach was used in 31 knees and the MMP approach, in 36 knees. Knees in both groups were compared for component position and alignment, knee alignment, length of the skin incision, range of motion, Visual Analog Scale score, muscle torques, Knee Society Score, Western Ontario and McMaster Universities Osteoarthritis Index, and number of complications., Results: There were no major intergroup differences in any of the clinical and radiographic outcomes assessed at the final follow-up examination., Conclusions: On the basis of numbers studied, the m-QS group, which requires more technique, showed equivalent results with the MMP group in the postoperative 5 years. Preservation of the extensor mechanism in the m-QS approach could not ensure any improvement in the clinical outcomes during the mid-term follow-up duration.