The Medial Patellofemoral Ligament Is a Dynamic and Anisometric Structure: An In Vivo Study on Length Changes and Isometry

2019 ◽  
Vol 47 (7) ◽  
pp. 1645-1653 ◽  
Author(s):  
Willem A. Kernkamp ◽  
Cong Wang ◽  
Changzou Li ◽  
Hai Hu ◽  
Ewoud R.A. van Arkel ◽  
...  
Keyword(s):  
Knee Flexion ◽  
Medial Patellofemoral Ligament ◽  
Length Change ◽  
High Rate ◽  
Mpfl Reconstruction ◽  
Full Extension ◽  
3 Dimensional ◽  
Technical Errors ◽  
Length Changes

Background: Medial patellofemoral ligament (MPFL) reconstruction is associated with a high rate of complications, including recurrent instability and persistent knee pain. Technical errors are among the primary causes of these complications. Understanding the effect of adjusting patellofemoral attachments on length change patterns may help surgeons to optimize graft placement during MPFL reconstruction and to reduce graft failure rates. Purpose: To determine the in vivo length changes of the MPFL during dynamic, weightbearing motion and to map the isometry of the 3-dimensional wrapping paths from various attachments on the medial femoral epicondyle to the patella. Study Design: Descriptive laboratory study. Methods: Fifteen healthy participants were studied with a combined computed tomography and biplane fluoroscopic imaging technique during a lunge motion (full extension to ~110° of flexion). On the medial femoral epicondyle, 185 attachments were projected, including the anatomic MPFL footprint, which was divided into 5 attachments (central, proximal, distal, posterior, and anterior). The patellar MPFL area was divided into 3 possible attachments (proximal, central, and distal). The length changes of the shortest 3-dimensional wrapping paths of the various patellofemoral combinations were subsequently measured and mapped. Results: For the 3 patellar attachments, the most isometric attachment, with an approximate 4% length change, was located posterior and proximal to the anatomic femoral MPFL attachment, close to the adductor tubercle. Attachments proximal and anterior to the isometric area resulted in increasing lengths with increasing knee flexion, whereas distal and posterior attachments caused decreasing lengths with increasing knee flexion. The anatomic MPFL was tightest in extension, decreased in length until approximately 30° of flexion, and then stayed near isometric for the remainder of the motion. Changing both the femoral and patellar attachments significantly affected the length changes of the anatomic MPFL ( P < .001 for both). Conclusion: The most isometric location for MPFL reconstruction was posterior and proximal to the anatomic femoral MPFL attachment. The anatomic MPFL is a dynamic, anisometric structure that was tight in extension and early flexion and near isometric beyond 30° of flexion. Clinical Relevance: Proximal and anterior MPFL tunnel positioning should be avoided, and the importance of anatomic MPFL reconstruction is underscored with the results found in this study.

scholarly journals Automatic string generation for estimating in vivo length changes of the medial patellofemoral ligament during knee flexion

2014 ◽  
Vol 52 (6) ◽  
pp. 511-520 ◽  
Author(s):  
Matthias Graf ◽  
Salomon Diether ◽  
Lazaros Vlachopoulos ◽  
Sandro Fucentese ◽  
Philipp Fürnstahl
Keyword(s):  
Knee Flexion ◽  
Medial Patellofemoral Ligament ◽  
Length Changes

scholarly journals Simulation of varying femoral attachment sites of medial patellofemoral ligament using a musculoskeletal multi-body model

2015 ◽  
Vol 1 (1) ◽  
pp. 547-551 ◽  
Author(s):  
A. Geier ◽  
T. Tischer ◽  
R. Bader
Keyword(s):  
Knee Flexion ◽  
Medial Patellofemoral Ligament ◽  
Numerical Study ◽  
Patellofemoral Instability ◽  
Length Change ◽  
Systematic Evaluation ◽  
Parameter Study ◽  
Femoral Attachment ◽  
Attachment Sites ◽  
Length Changes

AbstractThe medial patellofemoral ligament (MPFL) is a key structure in the treatment of habitual and traumatic patellofemoral instability. However, there exists little knowledge about its behaviour during deep knee flexion after femoral refixation. Since improper femoral attachment sites may lead to unnatural length change patterns in the ligament and consequently to osteoarthritis due to pathological femoro-patellar contact pressure, the understanding of the patella kinematics and MPFL behaviour is crucial.The purpose of this numerical study was to compute the six-degree-of-freedom motion pattern of the human patella during deep knee flexion for systematic analysis of varying landmarks for the femoral attachment in medial patellofemoral ligament reconstruction surgery by means of multibody simulation.Therefore, based on a previously presented musculoskeletal model [1] the dynamic pathways of the patella were computed. Then, the spatial motion was approximated by rheonomic polynomials and exploited for systematic evaluation of the MPFL length change patterns. Hence, 16 femoral attachment points at a radius of 5 mm and 10 mm around the radiographic centre point [2] were defined and the absolute length changes were recorded during deep knee flexion to 120 degree.This approach allows for a systematic evaluation of numerous MPFL attachment sites while exploiting the physiological patella kinematics. The patella kinematics including shift, flexion, tilt and rotation as well as the MPFL length change patterns were consistent to in vitro and in vivo data in the literature [3–7] and therefore indicate validity of the numerical approach. The parameter study on the femoral attachment site should enable to determine the most isometric point and non-isometric variations corresponding to patellofemoral instability, arthritis or high graft load.

Length Change Behavior of Virtual Medial Patellofemoral Ligament Fibers During In Vivo Knee Flexion

2015 ◽  
Vol 43 (5) ◽  
pp. 1165-1171 ◽  
Author(s):  
Si Young Song ◽  
Chae-Hyun Pang ◽  
Chan Hyoek Kim ◽  
Jeehyoung Kim ◽  
Mi Lim Choi ◽  
...  
Keyword(s):  
Knee Flexion ◽  
Medial Patellofemoral Ligament ◽  
Length Change ◽  
Change Behavior

scholarly journals Medial collateral ligament reconstruction graft isometry is effected by femoral position more than tibial position

2021 ◽  
Author(s):  
Christoph Kittl ◽  
James Robinson ◽  
Michael J. Raschke ◽  
Arne Olbrich ◽  
Andre Frank ◽  
...  
Keyword(s):  
Medial Collateral Ligament ◽  
Knee Flexion ◽  
Length Change ◽  
Collateral Ligament ◽  
Complex Behaviour ◽  
Femoral Attachment ◽  
Attachment Sites ◽  
Custom Made ◽  
Length Changes ◽  
Graft Length

Abstract Purpose The purpose of this study was to examine the length change patterns of the native medial structures of the knee and determine the effect on graft length change patterns for different tibial and femoral attachment points for previously described medial reconstructions. Methods Eight cadaveric knee specimens were prepared by removing the skin and subcutaneous fat. The sartorius fascia was divided to allow clear identification of the medial ligamentous structures. Knees were then mounted in a custom-made rig and the quadriceps muscle and the iliotibial tract were loaded, using cables and hanging weights. Threads were mounted between tibial and femoral pins positioned in the anterior, middle, and posterior parts of the attachment sites of the native superficial medial collateral ligament (sMCL) and posterior oblique ligament (POL). Pins were also placed at the attachment sites relating to two commonly used medial reconstructions (Bosworth/Lind and LaPrade). Length changes between the tibiofemoral pin combinations were measured using a rotary encoder as the knee was flexed through an arc of 0–120°. Results With knee flexion, the anterior fibres of the sMCL tightened (increased in length 7.4% ± 2.9%) whilst the posterior fibres slackened (decreased in length 8.3% ± 3.1%). All fibre regions of the POL displayed a uniform lengthening of approximately 25% between 0 and 120° knee flexion. The most isometric tibiofemoral combination was between pins placed representing the middle fibres of the sMCL (Length change = 5.4% ± 2.1% with knee flexion). The simulated sMCL reconstruction that produced the least length change was the Lind/Bosworth reconstruction with the tibial attachment at the insertion of the semitendinosus and the femoral attachment in the posterior part of the native sMCL attachment side (5.4 ± 2.2%). This appeared more isometric than using the attachment positions described for the LaPrade reconstruction (10.0 ± 4.8%). Conclusion The complex behaviour of the native MCL could not be imitated by a single point-to-point combination and surgeons should be aware that small changes in the femoral MCL graft attachment position will significantly effect graft length change patterns. Reconstructing the sMCL with a semitendinosus autograft, left attached distally to its tibial insertion, would appear to have a minimal effect on length change compared to detaching it and using the native tibial attachment site. A POL graft must always be tensioned near extension to avoid capturing the knee or graft failure.

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 Is Diagnostic Arthroscopy at the Time of Medial Patellofemoral Ligament Reconstruction Necessary?

2020 ◽  
Vol 8 (8) ◽  
pp. 232596712094565
Author(s):  
Christopher L. Shultz ◽  
Samuel N. Schrader ◽  
Benjamin D. Packard ◽  
Daniel C. Wascher ◽  
Gehron P. Treme ◽  
...  
Keyword(s):  
Postoperative Pain ◽  
Knee Flexion ◽  
Medial Patellofemoral Ligament ◽  
Perioperative Complications ◽  
Mpfl Reconstruction ◽  
Tibial Tubercle ◽  
Level Of Evidence ◽  
Diagnostic Arthroscopy ◽  
Patient Reported ◽  
Arthroscopic Procedures

Background: Although medial patellofemoral ligament (MPFL) reconstruction is well described for patellar instability, the utility of arthroscopy at the time of stabilization has not been fully defined. Purpose: To determine whether diagnostic arthroscopy in conjunction with MPFL reconstruction is associated with improvement in functional outcome, pain, and stability or a decrease in perioperative complications. Study Design: Cohort study; Level of evidence, 3. Methods: Patients who underwent primary MPFL reconstruction without tibial tubercle osteotomy were reviewed (96 patients, 101 knees). Knees were divided into MPFL reconstruction without arthroscopy (n = 37), MPFL reconstruction with diagnostic arthroscopy (n = 41), and MPFL reconstruction with a targeted arthroscopic procedure (n = 23). Postoperative pain, motion, imaging, operative findings, perioperative complications, need for revision procedure, and postoperative Kujala scores were recorded. Results: Pain at 2 weeks and 3 months postoperatively was similar between groups. Significantly improved knee flexion at 2 weeks was seen after MPFL reconstruction without arthroscopy versus reconstruction with diagnostic and reconstruction with targeted arthroscopic procedures (58° vs 42° and 48°, respectively; P = .02). Significantly longer tourniquet times were seen for targeted arthroscopic procedures versus the diagnostic and no arthroscopic procedures (73 vs 57 and 58 min, respectively; P = .0002), and significantly higher Kujala scores at follow-up were recorded after MPFL reconstruction without arthroscopy versus reconstruction with diagnostic and targeted arthroscopic procedures (87.8 vs 80.2 and 70.1, respectively; P = .05; 42% response rate). There was no difference between groups in knee flexion, recurrent instability, or perioperative complications at 3 months. Diagnostic arthroscopy yielded findings not previously appreciated on magnetic resonance imaging (MRI) in 35% of patients, usually resulting in partial meniscectomy. Conclusion: Diagnostic arthroscopy with MPFL reconstruction may result in findings not previously appreciated on MRI. Postoperative pain, range of motion, and risk of complications were equal at 3 months postoperatively with or without arthroscopy. Despite higher Kujala scores in MPFL reconstruction without arthroscopy, the relationship between arthroscopy and patient-reported outcomes remains unclear. Surgeons can consider diagnostic arthroscopy but should be aware of no clear benefits in patient outcomes.

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.

Comparison of Patellofemoral Kinematics and Stability After Medial Patellofemoral Ligament and Medial Quadriceps Tendon–Femoral Ligament Reconstruction

2020 ◽  
Vol 48 (9) ◽  
pp. 2252-2259
Author(s):  
Robert Spang ◽  
Jonathan Egan ◽  
Philip Hanna ◽  
Aron Lechtig ◽  
Daniel Haber ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Medial Patellofemoral Ligament ◽  
Quadriceps Tendon ◽  
Mpfl Reconstruction ◽  
Fixation Method ◽  
Full Extension ◽  
Lateral Translation ◽  
Patellar Position ◽  
Significant Difference ◽  
Contact Pressures

Background: There is a lack of evidence regarding the optimum extensor-sided fixation method for medial patellofemoral ligament (MPFL) reconstruction. There is increased interest in avoiding patellar drilling via soft tissue–only fixation to the distal quadriceps, thus reconstructing the medial quadriceps tendon–femoral ligament (MQTFL). The biomechanical implications of differing extensor-sided fixation constructs remain unknown. Hypothesis: The null hypothesis was there would be no differences between traditional MPFL reconstruction and MQTFL reconstruction with respect to resistance to lateral translation, patellar position, or patellofemoral contact pressures. Study Design: Controlled laboratory study. Methods: Nine adult knee specimens were mounted on a jig that applied static, physiologic loads to the quadriceps tendons. Patellar position and orientation, knee flexion angle, and patellofemoral pressure were recorded at 8 different flexion angles between 0° and 110°. Additionally, a lateral patellar excursion test was conducted wherein a load was applied directly to the patella in the lateral direction with the knee at 30° of flexion and subjected to 2-N quadriceps loads. Testing was conducted under 4 conditions: intact, transected MPFL, MQTFL reconstruction, and MPFL reconstruction. For MQTFL reconstruction, the surgical technique established by Fulkerson was employed. For MPFL reconstruction, a traditional technique was utilized. Results: The patellar excursion test showed no significant difference between the MQTFL and intact states with respect to lateral translation. MPFL reconstruction led to significantly less lateral translation ( P < .05) than all other states. There were no significant differences between MPFL and MQTFL reconstructions with respect to peak patellofemoral contact pressure. MPFL and MQTFL reconstructions both resulted in increased internal rotation of the patella with the knee in full extension. Conclusion: Soft tissue-only extensor-sided fixation to the distal quadriceps (MQTFL) during patella stabilization appears to re-create native stability in this time 0 cadaver model. Fixation to the patella (MPFL) was associated with increased resistance to lateral translation. Clinical Relevance: Evolving anatomic knowledge and concern for patellar fracture has led to increased interest in MQTFL reconstruction. Both MQTFL and MPFL reconstructions restored patellofemoral stability to lateral translation without increasing contact pressures under appropriate graft tensioning, with MQTFL more closely restoring native resistance to lateral translation at the time of surgery.

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