Comparation and evaluation of the accuracy of the sulcus localization method to establish the medial patellofemoral ligament femoral tunnel: a cadaveric and clinical study

Abstract

BackgroundIn anatomic medial patellofemoral ligament (MPFL) reconstruction, malpositioning of the MPFL femoral tunnel is common. A palpable sulcus reportedly exists at the anatomic femoral attachment of the MPFL. The present study aimed to investigate the accuracy of the sulcus localization method to establish the MPFL femoral tunnel.MethodsA cadaveric study was first done on 12 knees to evaluate the accuracy of the sulcus localization method to establish the entry points of the MPFL femoral tunnel in comparison with the midpoint and fluoroscopic localization methods. The center of the native MPFL femoral attachment was served as the reference in the cadaveric study. A clinical study was then performed to further evaluate the accuracy of the sulcus localization method in 53 patients (60 knees). Schöttle’s point was served as the reference in the clinical study. Femoral tunnel placement was defined as accurate when it was less than 5 mm from Schöttle’s point. In both the cadaveric and clinical studies, MPFL femoral tunnel placement was assessed on postoperative reconstructed three-dimensional computed tomography images. In the cadaveric study, the accuracy of different localization methods was compared using analysis of variance.ResultsIn the cadaveric study, the mean distances from the native MPFL attachment to the femoral tunnel entry point were 4.2 ± 1.0 mm (range 2.4–5.6 mm), 4.4 ± 1.4 mm (range 1.8–6.6 mm) and 2.9 ± 0.8 mm (range 1.9–4.4 mm) using the midpoint, fluoroscopic, and sulcus localization methods, respectively; this distance significantly differed between the midpoint and sulcus localization methods, and between the fluoroscopic and sulcus localization methods (p ≤ .05). While there were no significant differences between the midpoint and fluoroscopic localization methods (n.s.). In the clinical study, the mean distance between the femoral tunnel and Schöttle’s point was 3.5 ± 1.5 mm (range 0.4–6.1 mm), with accurate tunnel placement achieved in 49 of 60 cases (82%).ConclusionThe sulcus localization method can accurately guide MPFL femoral tunnel placement. This method might be useful for orthopedic surgeons.Level of evidenceIV

Radiographic Reference Points Do Not Ensure Anatomic Femoral Fixation Sites in Medial Patellofemoral Ligament Reconstruction: A Quantified Anatomic Localization Method Based on the Saddle Sulcus

“…All of the mean direct distances from the sulcus to the reported reference radiographic points exceeded 5 mm, a reported small malposition resulting in dramatic increase in patellofemoral pressure and alteration of graft isometry. 8,24 To our knowledge, this is the first study to quantify the anatomic landmark (saddle sulcus), which was mentioned and described in several previous studies 4,29,30 without further examination.…”

“…The palpation of these osseous landmarks through an approximately 2-cm skin incision could be realized after sufficient release and exposure, which was believed to be an accurate and feasible intraoperative technique in a previous study. 29…”

“…However, our procedure used the osseous landmarks alone to create a coordinate to locate the anatomic position, which required approximately 1 to 2 minutes to find the precise and effective location. 29 Considering the anterior and posterior medial femoral condyle width to be 100%, Nomura et al 16 and Stephen et al 24 identified that the femoral MPFL insertion was located around 60% from the anterior margin of the medial femoral condyle in normal cadaveric knees. However, trochlear dysplasia, one of the predominant risk factors for patellar instability, 2 either with a spur or a cliff, would potentially change the proportion of the MPFL insertion site on the whole medial condyle diameter and significantly affect patellofemoral kinematics.…”

“…Moreover, the midpoint localization of the AT and ME showed less accurate tunnel positioning and ignored individual variability in most cases. 29…”

Computed Tomography Imaging Analysis of the MPFL Femoral Footprint Morphology and the Saddle Sulcus: Evaluation of 1094 Knees

“…Recently, direct assessment of the femoral anatomy has been proposed for MPFL femoral tunnel placement. 58 , 60 Bicos et al 7 were the first to characterize a saddle region where the MPFL originated from the femoral aspect. Baldwin 3 and Ziegler et al 60 also described the MPFL as being consistently and anatomically attached from the osseous saddle region between neighboring landmarks, including the adductor tubercle (AT), medial epicondyle (ME), and medial gastrocnemius tubercle (MGT).…”