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

2020 ◽  
pp. 036354652097242
Author(s):  
Jiebo Chen ◽  
Kang Han ◽  
Jia Jiang ◽  
Xiaoqiao Huangfu ◽  
Song Zhao ◽  
...  
Keyword(s):  
Medial Patellofemoral Ligament ◽  
Femoral Tunnel ◽  
Average Distance ◽  
Three Dimensional ◽  
Reference Points ◽  
Mpfl Reconstruction ◽  
Tunnel Placement ◽  
Precise Position ◽  
Fresh Frozen ◽  
Anatomic Localization

Background: Medial patellofemoral ligament (MPFL) reconstruction is one of the main treatments for lateral patellar translation. Based on intraoperative true lateral radiographs, the accepted methods for femoral MPFL tunnel location are potentially inaccurate. Direct assessment of anatomic characteristics during surgery through palpation of the anatomic landmarks involving the saddle sulcus might help eliminate tunnel malposition. Hypothesis: The saddle sulcus is a reliable osseous landmark where the MPFL attaches for tunnel placement. Study Design: Descriptive laboratory study. Methods: A total of 9 fresh-frozen unpaired human cadaveric knees were dissected; MPFL insertion point and relative osseous structures were marked. Three-dimensional images and transformed true lateral radiographs were obtained for analysis; 3 previously reported radiographic reference points for MPFL femoral tunnel placement were determined on all images and compared with the anatomic insertion. Results: A saddle sulcus consistently existed where the MPFL was attached, located at 11.7 ± 5.9 mm from the apex of the adductor tubercle (AT) to the medial epicondyle (ME), 62.8% of the average distance between the apexes of the AT and ME, and 5.6 ± 2.8 mm perpendicular-posterior to the border connecting the AT and ME. The reported radiographic reference points were located at average distances of 6.2 ± 3.2 mm (Schöttle method), 5.9 ± 2.3 mm (Redfern method), and 7.3 ± 6.6 mm (Fujino method) from the saddle sulcus center on the true lateral radiographs. Conclusion: The saddle sulcus was a reliable landmark where the MPFL was anatomically attached, located approximately 12 mm from the AT to the ME (approximately 60% along a line from the AT to the ME) and 6 mm perpendicular-posterior to the border connecting the apexes of the AT and ME. Additionally, the saddle sulcus position presented variability on the femoral aspect of different knees. All of the average direct distances from the sulcus to the reference radiographic points exceeded 5 mm, and tunnel localizations on a true lateral radiograph were inaccurate. Clinical Relevance: This study demonstrates the potential precise position of the saddle sulcus, according to the ME and AT, as a reliable anatomic landmark for MPFL femoral tunnel location. Radiographic reference points were not accurate during MPFL reconstruction. Direct palpation of the landmarks might be effective for femoral MPFL tunnel placement.

scholarly journals Medial Patellofemoral Ligament Reconstruction Femoral Tunnel Accuracy

2017 ◽  
Vol 5 (2) ◽  
pp. 232596711668774 ◽  
Author(s):  
Laurie A. Hiemstra ◽  
Sarah Kerslake ◽  
Mark Lafave
Keyword(s):  
Quality Of Life ◽  
Medial Patellofemoral Ligament ◽  
Femoral Tunnel ◽  
Patellofemoral Instability ◽  
Mpfl Reconstruction ◽  
Tunnel Position ◽  
Femoral Tunnel Position ◽  
The Mean ◽  
Femoral Tunnel Placement

Background: Medial patellofemoral ligament (MPFL) reconstruction is a procedure aimed to reestablish the checkrein to lateral patellar translation in patients with symptomatic patellofemoral instability. Correct femoral tunnel position is thought to be crucial to successful MPFL reconstruction, but the accuracy of this statement in terms of patient outcomes has not been tested. Purpose: To assess the accuracy of femoral tunnel placement in an MPFL reconstruction cohort and to determine the correlation between tunnel accuracy and a validated disease-specific, patient-reported quality-of-life outcome measure. Study Design: Case series; Level of evidence, 4. Methods: Between June 2008 and February 2014, a total of 206 subjects underwent an MPFL reconstruction. Lateral radiographs were measured to determine the accuracy of the femoral tunnel by measuring the distance from the center of the femoral tunnel to the Schöttle point. Banff Patella Instability Instrument (BPII) scores were collected a mean 24 months postoperatively. Results: A total of 155 (79.5%) subjects had adequate postoperative lateral radiographs and complete BPII scores. The mean duration of follow-up (±SD) was 24.4 ± 8.2 months (range, 12-74 months). Measurement from the center of the femoral tunnel to the Schöttle point resulted in 143 (92.3%) tunnels being categorized as “good” or “ideal.” There were 8 failures in the cohort, none of which occurred in malpositioned tunnels. The mean distance from the center of the MPFL tunnel to the center of the Schöttle point was 5.9 ± 4.2 mm (range, 0.5-25.9 mm). The mean postoperative BPII score was 65.2 ± 22.5 (range, 9.2-100). Pearson r correlation demonstrated no statistically significant relationship between accuracy of femoral tunnel position and BPII score ( r = –0.08; 95% CI, –0.24 to 0.08). Conclusion: There was no evidence of a correlation between the accuracy of MPFL reconstruction femoral tunnel in relation to the Schöttle point and disease-specific quality-of-life scores. Graft failure was not related to femoral tunnel placement. The patellofemoral instability population is complex, and patients present with multiple risk factors that, in addition to the accuracy of femoral tunnel position, contribute to quality of life and warrant further investigation.

Ability of Medial Patellofemoral Ligament Reconstruction to Overcome Lateral Patellar Motion in the Presence of Trochlear Flattening: A Cadaveric Biomechanical Study

2021 ◽  
pp. 036354652110410
Author(s):  
Amrit V. Vinod ◽  
Alex M. Hollenberg ◽  
Melissa A. Kluczynski ◽  
John M. Marzo
Keyword(s):  
Repeated Measures ◽  
Knee Flexion ◽  
Medial Patellofemoral Ligament ◽  
Operative Procedure ◽  
Biomechanical Study ◽  
Mpfl Reconstruction ◽  
Trochlear Groove ◽  
Sulcus Angle ◽  
Fresh Frozen ◽  
Patellar Stability

Background: Medial patellofemoral ligament (MPFL) reconstruction is an established operative procedure to restore medial restraining force in patients with patellar instability. In the setting of a shallow sulcus, it is unclear whether an isolated MPFL reconstruction is sufficient to restore patellofemoral stability. Hypothesis: Progressively increasing the sulcus angle would have an adverse effect on the ability of an MPFL reconstruction to restrain lateral patellar motion. Study Design: Controlled laboratory study. Methods: Seven fresh-frozen human cadaveric knees were harvested and prepared for experimentation. Each specimen was run through the following test conditions: native, lateral retinacular release, lateral retinacular repair, MPFL release, MPFL reconstruction, and MPFL reconstruction with trochlear flattening. Four 3-dimensional printed wedges (10°, 20°, 30°, and 40°) were created to insert beneath the native trochlea to raise the sulcus angle incrementally and simulate progressive trochlear flattening. For each test condition, the knee was positioned at 0°, 15°, 30°, and 45° of flexion, and the force required to displace the patella 1 cm laterally at 10 mm/s was measured. Group comparisons were made with repeated measures analysis of variance. Results: In the setting of an MPFL reconstruction, as the trochlear groove was incrementally flattened, the force required to laterally displace the patella progressively decreased. A 10° increase in the sulcus angle significantly reduced the force at 15° ( P = .01) and 30° ( P = .03) of knee flexion. The force required to laterally displace the patella was also significantly lower at all knee flexion angles after the addition of the 20°, 30°, and 40° wedges ( P≤ .05). Specifically, a 20° increase in the sulcus angle reduced the force by 29% to 36%; a 30° increase, by 35% to 43%; and a 40° increase, by 40% to 47%. Conclusion: Despite an MPFL reconstruction, the force required to laterally displace the patella decreased as the sulcus angle was increased in our cadaveric model. Clinical Relevance: An isolated MPFL reconstruction may not be sufficient to restore patellar stability in the setting of a shallow or flat trochlea. Patients with an abnormal sulcus angle may have recurrent instability postoperatively if treated with an isolated MPFL reconstruction.

scholarly journals Failure Analysis in Patients With Patellar Redislocation After Primary Isolated Medial Patellofemoral Ligament Reconstruction

2020 ◽  
Vol 8 (6) ◽  
pp. 232596712092617 ◽  
Author(s):  
Matthias J. Feucht ◽  
Julian Mehl ◽  
Philipp Forkel ◽  
Andrea Achtnich ◽  
Andreas Schmitt ◽  
...  
Keyword(s):  
Revision Surgery ◽  
Medial Patellofemoral Ligament ◽  
Femoral Tunnel ◽  
Trochlear Dysplasia ◽  
Patellofemoral Instability ◽  
Tibial Tuberosity ◽  
Mpfl Reconstruction ◽  
Tunnel Position ◽  
Femoral Tunnel Position ◽  
Valgus Malalignment

Background: Reconstruction of the medial patellofemoral ligament (MPFL) has become a popular surgical procedure to address patellofemoral instability. As a consequence of the growing number of MPFL reconstructions performed, a higher rate of failures and revision procedures has been seen. Purpose: To perform a failure analysis in patients with patellar redislocation after primary isolated MPFL reconstruction. Study Design: Case series; Level of evidence, 4. Methods: Patients undergoing revision surgery for reinstability after primary isolated MPFL reconstruction were included. Clinical notes were reviewed to collect demographic data, information on the primary surgery, and the mechanism of patellar redislocation (traumatic vs nontraumatic). Preoperative imaging was analyzed regarding femoral tunnel position and the prevalence of anatomic risk factors (ARFs) associated with patellofemoral instability: trochlear dysplasia (types B through D), patella alta (Caton-Deschamps index >1.2, patellotrochlear index <0.28), lateralization of the tibial tuberosity (tibial tuberosity–trochlear groove distance >20 mm, tibial tuberosity–posterior cruciate ligament [TT-PCL] distance >24 mm), valgus malalignment (mechanical valgus axis >5°), and torsional deformity (internal femoral torsion >25°, external tibial torsion >35°). The prevalence of ARF was compared between patients with traumatic and nontraumatic redislocations and between patients with anatomic and nonanatomic femoral tunnel position. Results: A total of 26 patients (69% female) with a mean age of 25 ± 7 years were included. The cause of redislocation was traumatic in 31% and nontraumatic in 69%. Position of the femoral tunnel was considered nonanatomic in 50% of patients. Trochlear dysplasia was the most common ARF with a prevalence of 50%, followed by elevated TT-PCL distance (36%) and valgus malalignment (35%). The median number of ARFs per patient was 3 (range, 0-6), and 65% of patients had 2 or more ARFs. Patients with nontraumatic redislocations showed significantly more ARFs per patient, and the presence of 2 or more ARFs was significantly more common in this group. No significant difference was observed between patients with anatomic versus nonanatomic femoral tunnel position. Conclusion: Multiple anatomic risk factors and femoral tunnel malposition are commonly observed in patients with reinstability after primary MPFL reconstruction. Before revision surgery, a focused clinical examination and adequate imaging including radiographs, magnetic resonance imaging (MRI), standing full-leg radiographs, and torsional measurement with computed tomography or MRI are recommended to assess all relevant anatomic parameters to understand an individual patient’s risk profile. During revision surgery, care must be taken to ensure anatomic placement of the femoral tunnel through use of anatomic and/or radiographic landmarks.

Analysis of Graft Length Change Patterns in Medial Patellofemoral Ligament Reconstruction via a Fluoroscopic Guidance Method

2018 ◽  
Vol 46 (5) ◽  
pp. 1150-1157 ◽  
Author(s):  
Takehiko Matsushita ◽  
Daisuke Araki ◽  
Yuichi Hoshino ◽  
Shinya Oka ◽  
Kyohei Nishida ◽  
...  
Keyword(s):  
Medial Patellofemoral Ligament ◽  
Femoral Tunnel ◽  
Length Change ◽  
Lateral View ◽  
Mpfl Reconstruction ◽  
Original Position ◽  
Fluoroscopic Guidance ◽  
Change Pattern ◽  
Radiographic Parameters ◽  
Graft Length

Background: A fluoroscopic guidance method for medial patellofemoral ligament (MPFL) reconstruction has been widely used to determine the anatomic femoral attachment site. Purpose: To examine the graft length change patterns in MPFL reconstruction with a fluoroscopic guidance method. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Forty-four knees of 42 patients who underwent MPFL reconstruction for the treatment of recurrent patellar dislocation were examined prospectively. During surgery, suture anchors were inserted into the proximal one-third and center of the patella. A guide pin for the femoral tunnel was inserted into the position reported by Schöttle et al based on the true lateral view of the knee under fluoroscopic control. Changes in graft length patterns of the proximal and center anchors were examined through 0° to 120° of knee flexion. Favorable changes in length patterns were defined as meeting 2 of 3 criteria: (1) not long during flexion (≤3 mm between 30° and 120° of flexion) and either (2) nearly isometric during flexion between 0° and 90° or (3) slightly long during maximum extension (≤3 mm). Other patterns were considered unfavorable. If the change in length pattern was unfavorable, then the pin for the femoral tunnel was moved to different positions until it was favorable. Knees were separated into the favorable group and the unfavorable group. Differences between the groups regarding radiographic parameters were assessed. Student t test or chi-square test was used for statistical analysis. Results: Of the 44 knees, 31 (70.5%) showed favorable patterns. However, 13 knees (29.5%) showed unfavorable patterns; therefore, the position of the pin was changed. The mean ± SD distance from the original position to the final position was 5.3 ± 1.1 mm distal for 7 patients and 5.2 ± 0.4 mm posterodistal for 6 patients. Technical errors, including a nontrue lateral view and the tip of the wire not being in the determined area, were found for 4 of 13 knees in the unfavorable group. There was no statistical difference in radiographic parameters between the groups. Conclusion: The graft length change pattern could be nonphysiologic at the position determined through the fluoroscopic guidance method; thus, caution may be necessary. The change in length pattern should be checked before graft fixation. If the length change pattern is unfavorable, then it is advisable to move it approximately 5 to 7 mm distally or posterodistally from the first position.

scholarly journals A BIOMECHANICAL COMPARISON OF SUTURE ANCHOR VS. INTERFERENCE SCREW TECHNIQUE FOR PATELLAR FIXATION FOR MEDIAL PATELLOFEMORAL LIGAMENT RECONSTRUCTION

2019 ◽  
Vol 7 (3_suppl) ◽  
pp. 2325967119S0010
Author(s):  
Dragomi Mijic ◽  
Sanar Yokhana ◽  
Kunal Kalra
Keyword(s):  
Repeated Measures ◽  
Medial Patellofemoral Ligament ◽  
Suture Anchor ◽  
Interference Screw ◽  
T Test ◽  
Mpfl Reconstruction ◽  
Initial Stiffness ◽  
Significant Difference ◽  
Load To Failure ◽  
Fresh Frozen

Background: There are numerous techniques for MPFL reconstruction, however, one single technique has not been proven to be superior to another. Suture anchor reconstruction has been shown to provide stable fixation while decreasing the risk of patellar fracture. The aim of the study was to compare the stiffness and clinical load to failure of two common MPFL reconstruction techniques. Our hypothesis was that there would be no significant difference in the stiffness and the clinical load to failure between the suture anchor and interference screw reconstructions. Methods: Eight pairs of fresh frozen cadaveric knees were randomized into two groups undergoing MPFL reconstruction using either a suture anchor technique (n=8) or an interference screw technique (n=8). Testing was performed at 0, 30, 60, and 90 degrees of flexion for the native knee, transected medial structures, and reconstructed MPFL. Next, the reconstructed MPFL specimens were tested until failure in 0 degrees of flexion. T test, One-Way ANOVA, and repeated measures of ANOVA were used for statistical analysis, P values less than 0.05 were considered significant. Results: The average stiffness for the suture anchor and interference screw reconstructions was 12.02 ± 3.96 N/mm and 14.21 ± 4.20 N/mm, respectively (t test, p = 0.27), while average clinical load to failure was 256.57 ± 54.1 N and 237.81 ± 23.82 N, respectively (t test, p = 0.38). There was no significant difference in stiffness between the suture anchor and interference screw techniques at 0, 30, and 60 degrees of flexion. Conclusions: The suture anchor and interference screw reconstruction techniques produce comparable stiffness for sub-failure testing at 0 and 30 degrees of flexion. For testing to failure, the initial stiffness for both reconstruction techniques have been shown to be concordant with previously published values for the native MPFL. Both reconstruction techniques provide greater ultimate failure loads than those reported for the native MPFL in previous studies. Clinical Relevance: Suture anchor reconstruction described in our study provides another reliable option for the reconstruction of the medial patellofemoral ligament. [Figure: see text]

Accuracy and Learning Curve of Femoral Tunnel Placement in Medial Patellofemoral Ligament Reconstruction

2017 ◽  
Vol 30 (09) ◽  
pp. 879-886 ◽  
Author(s):  
Laurie Hiemstra ◽  
Catherine O'Brien ◽  
Mark Lafave ◽  
Sarah Kerslake
Keyword(s):  
Learning Curve ◽  
Ligament Reconstruction ◽  
Medial Patellofemoral Ligament ◽  
Femoral Tunnel ◽  
Medial Patellofemoral Ligament Reconstruction ◽  
Tunnel Placement ◽  
Surgical Time ◽  
Significant Difference ◽  
Schöttle’S Point ◽  
Femoral Tunnel Placement

AbstractThe purpose of this study was to assess the accuracy of femoral tunnel placement in a medial patellofemoral ligament reconstruction (MPFL-R) cohort. The secondary purpose was to establish the evidence of a learning curve to achieve acceptable femoral tunnel placement during MPFL-R. Two surgeons, using lateral radiographs, assessed 73 subjects post–MPFL-R. Femoral tunnel accuracy and direction of tunnel error were measured in relation to Schöttle's point (A–T distance). Interrater reliability (intraclass correlation coefficient 2,k) of these measures was calculated. Learning curve of accurate femoral tunnel placement was examined by dividing the patient cohort into quartiles. A one-way analysis of variance was used to assess the quartiles for accuracy of femoral tunnel position and surgical time. In relation to Schöttle's point, 66/73 (90.4%) femoral tunnels were categorized as being in a “good” or “excellent” position and 7/73 (9.6%) were categorized as being in a “poor” position. Evidence of an MPFL-R learning curve was established via a statistically significant difference in the mean A to T distance for the four quartiles (F [3, 69] = 6.41, p = 0.001). There was also a statistically significant difference in the surgical time for the four quartiles (F [3, 69] = 8.71, p = 0.001). In this series, accurate femoral tunnels were placed more than 90% of the time during MPFL-R. A clear learning curve for accurate femoral tunnel placement was demonstrated both with respect to distance of the tunnel from Schöttle point and with regard to surgical time. Level of evidence was IV.

Biomechanical Evaluation of Classic Solid and All-Soft Suture Anchors for Medial Patellofemoral Ligament Reconstruction

2017 ◽  
Vol 45 (7) ◽  
pp. 1622-1626 ◽  
Author(s):  
Michael G. Saper ◽  
Karim Meijer ◽  
Scott Winnier ◽  
John Popovich ◽  
James R. Andrews ◽  
...  
Keyword(s):  
Medial Patellofemoral Ligament ◽  
Failure Load ◽  
Articular Surface ◽  
Mpfl Reconstruction ◽  
Suture Anchors ◽  
Ultimate Failure Load ◽  
Mode Of Failure ◽  
Fixation Techniques ◽  
Fresh Frozen ◽  
Ultimate Failure

Background: Multiple techniques for patellar fixation with classic solid suture anchors (SAs) in medial patellofemoral ligament (MPFL) reconstruction have been described. Fixation of the graft to the patella with all-soft suture anchors (ASAs) has not been studied. Purpose/Hypothesis: To evaluate the biomechanical performance of 2 different MPFL patellar fixation techniques: ASA fixation and SA fixation. We hypothesized that the ASA group would show no statistical difference in the ultimate failure load and stiffness compared with the SA group. Study Design: Controlled laboratory study. Methods: Reconstruction of the MPFL with gracilis autografts was performed in 16 fresh-frozen cadaveric knees (mean age, 52.6 ± 9.0 years). The specimens were randomly assigned to 2 groups of 8 specimens each based on the method used to fix the graft to the medial patella: ASA or SA fixation. Patellar fixation with ASAs was completed with 2 parallel 1.8-mm anchors (Q-Fix, Smith & Nephew). Fixation with SAs was completed with 2 parallel 2.9-mm anchors (Osteoraptor, Smith & Nephew). The reconstructions were cyclically loaded for 10 cycles to 25 N and then loaded in tension at 6 mm/s until failure. Ultimate failure load (N), displacement (mm), stiffness (N/mm), and mode of failure were recorded for each specimen. Results: Load to failure testing showed an ultimate failure load of 228.5 ± 53.1 N in the ASA group. In the SA group, the ultimate failure load was 156.2 ± 84.9 N. The difference between the 2 groups was not statistically significant ( P = .064). Stiffness values between the ASA and SA groups were not significantly different (21.3 ± 4.1 N/mm vs 20.9 ± 9.3 N/mm, respectively, P = .905). The most common mode of failure in both groups was anchor pullout (8 of 8 in the ASA group; 6 of 8 in the SA group). Conclusion: This experimental study showed no statistically significant differences in biomechanical performance between 1.8-mm ASAs and 2.9-mm SAs. Clinical Relevance: Patellar fixation with 2 parallel ASAs may provide adequate patellar fixation for MPFL reconstruction, while their smaller diameter could potentially decrease the risks for patella fracture and violation of the articular surface in the cadaver model.

Optimal Fluoroscopic Angulation to Determine Intercondylar Notch Violation during Pediatric Medial Patellofemoral Ligament Reconstruction

2021 ◽  
Author(s):  
Derrick M. Knapik ◽  
Conor F. McCarthy ◽  
Ian Drummond ◽  
Raymond W. Liu ◽  
Allison Gilmore
Keyword(s):  
Ligament Reconstruction ◽  
Medial Patellofemoral Ligament ◽  
Femoral Tunnel ◽  
Kirschner Wire ◽  
Mpfl Reconstruction ◽  
Intercondylar Notch ◽  
Fluoroscopic Guidance ◽  
Medial Patellofemoral Ligament Reconstruction ◽  
Femoral Physis ◽  
Schöttle’S Point

AbstractPrevious anatomic data has suggested that during pediatric medial patellofemoral ligament (MPFL) reconstruction, the femoral tunnel must be angled distally and anteriorly to avoid damage to the distal femoral physis and then intercondylar notch. The purpose of this study was to determine the optimal degree of fluoroscopic angulation necessary to radiographically determine the presence of intercondylar notch violation. Fourteen adult cadaveric human femora were disarticulated and under fluoroscopic guidance, Schöttle's point was identified. A 0.62-mm Kirschner wire was then drilled through the condyle to create minimal notch violation. The femur was then placed on a level radiolucent table and coronal plane radiographs angled from −15 to 60 degrees were obtained in 5-degree increments to determine the fluoroscopic angle at which intercondylar notch violation was most evident. Grading of optimal fluoroscopic angle between two authors found that violation of the notch was the best appreciated at a mean angle of 43 ± 15 degrees from neutral. Results from this study emphasize the importance of angling the beam to essentially obtain a notch view to assess for a breech.

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