Intraoperative fluoroscopy during MPFL reconstruction improves the accuracy of the femoral tunnel position
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Reconstruction of the medial patellofemoral ligament (MPFL) has been established as standard of care for patellofemoral instability. An anatomic femoral tunnel position has been shown to be a prerequisite for restoration of patellofemoral stability and biomechanics. However, the incidence of malpositioning of the femoral tunnel during MPFL reconstruction continues to be notable. Palpation of anatomic landmarks and intraoperative fluoroscopy are the two primary techniques for tunnel placement. The aim of this study was to compare the accuracy of these two methods for femoral tunnel placement.
From 2016 to 2017, 64 consecutive patients undergoing MPFL reconstruction for patelllofemoral instability were prospectively enrolled. During surgery, the presumed femoral MPFL insertion was identified by both palpation of anatomic landmarks and using fluoroscopy, both of these points were separately documented on true lateral radiographs. They were then analysed and deviations from the Schoettle’s Point were measured as anterior–posterior and proximal–distal deviations. A tunnel position within a radius of 7 mm around the Schoettle’s Point was designated as an “accurate tunnel position”.
Compared to the method of palpation, fluoroscopy led to significantly more anatomic femoral tunnel positoning (p < 0.0001). The mean proximal–distal and anterior–posterior distances between the femoral insertion site identified by palpation and the Schoettle’s Point were 5.7 ± 4.5 mm (0.3–20.3 mm) and 4.1 ± 3.7 mm (0.1–20.3 mm), respectively, versus 1.7 ± 0.9 mm (0.1–3.6 mm) and 1.8 ± 1.3 mm (0.1–4.8 mm) for fluoroscopy, respectively. Using fluoroscopy, all femoral insertion sites were identified within a 7 mm radius around the centre of the Schoettle’s Point. In contrast, only 52% (33) of femoral insertion sites identified by palpation were within this radius. These data were independent of patients’ age, gender and BMI. No improvement in accuracy of femoral tunnel positions was detected over time.
The main finding of this study was that, compared to the method of palpation of anatomic landmarks, the use of intraoperative fluoroscopy in MPFL reconstruction leads to more accurate femoral tunnel positioning. Based on these results, the use of intraoperative fluoroscopy has to be recommended for femoral tunnel placement in daily surgical practice to minimize the incidence of malpositioning and to restore native patellofemoral biomechanics.
Level III Case-control study.
KeywordsMPFL reconstruction Femoral tunnel position Intraoperative fluoroscopy
Medial patellofemoral ligement
Body mass index
PK participated in the design of the study, collected data, performed the statistical analysis and drafted the manuscript. SS, TP and AK have been involved in drafting the manuscript and revising it critically. SS performed all surgeries. AW helped to perform the statistical analysis and interpretation of data. BB participated in the design and coordination of the study. VJ conceived of the study and participated in its design. All authors read and approved the final manuscript.
Compliance with ethical standards
Conflict of interest
All authors declare that there is no conflict of interests.
Ethical approval was obtained from the ethics committee of the University of Witten/Herdecke, Germany (ID 146/2014). All procedures involving human participants were in accordance with the 1964 Helsinki declaration and its later amendments.
Informed consent was obtained from all participants.
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