Summary

The purpose of this study was to perform systematic review and meta-analysis of the radiographic landmarks reported in the literature for the anatomic MPFLR femoral origin.

Abstract

Introduction

Accurate femoral tunnel positioning for medial patellofemoral ligament reconstruction (MPFLR) is essential for maintaining ligament isometry throughout knee range of motion. Although it is accepted practice to utilize Schöttle’s point as a surrogate for the anatomic location of the MPFL, there may be considerable individual variability. The purpose of this study was to perform systematic review and meta-analysis of the radiographic landmarks reported in the literature for the anatomic MPFLR femoral origin.

Methods

A meta-analysis was performed of the PubMed, EMBASE, and Cochrane Library databases to identify studies that reported the radiographic position of the MPFLR femoral tunnel position. Included studies were required to report the position of the MPFLR femoral tunnel relative to the posterior cortical extension line (PCEL) in the anterior-posterior direction and to either Blumensaat’s line or another radiographic landmark in the proximal-distal direction. Studies that reported the location of MPFLR femoral tunnel relative to anatomical landmarks, such as the adductor tubercle or medial epicondyle, were excluded. Microsoft Excel was used to calculate weighted means and standard deviations.

Results

Seven studies were included, ranging in publication date from 2007 to 2022. A total of 75 cadaveric knees were analyzed with a mean age of 62.9 ±12.4 years. The average distance from the PCEL to the MPFLR femoral tunnel was 2.24 ± 4.66 mm anterior [95% CI: 1.19, 3.30], with individual studies reporting a range from 4.80 mm posterior to 8.80 mm anterior to the PCEL.

The average distance from Blumensaat’s line to the MPFLR femoral tunnel was 1.36 ± 2.11 mm proximal [95% CI: 0.86, 1.87], ranging from 0.90 mm distal to 4.70 mm proximal to Blumensaat’s. Two studies reported the mean distance from the condylar transition line, averaging 1.35 ± 0.30 mm distal [95% CI: 1.20, 1.50], ranging from 5.70 mm distal to 2.50 mm distal to the condylar transition line.

Conclusion

This meta-analysis highlights the substantial heterogeneity in the radiographic location of the anatomic origin of the MPFLR relative to the PCEL and Blumensaat’s line. The findings underscore the importance of integrating radiographic data with intraoperative (i.e. osseous anatomic) landmarks to enhance precision of tunnel placement and optimize graft isometry. Further studies are needed to refine these radiographic landmarks and explore their relationship with functional outcomes following MPFLR.