Medial Quadriceps Tendon Femoral Ligament Research Articles

Effect of Medial Patellofemoral Complex Reconstruction Technique on Patellofemoral Contact Pressure, Contact Area, and Kinematics.

Medial patellofemoral ligament (MPFL) reconstruction is considered by many to be the gold standard to treat lateral patellar instability; however, some investigators have reported good clinical results after isolated medial quadriceps tendon-femoral ligament (MQTFL) reconstruction or a combined MPFL/MQTFL reconstruction. A handful of studies have preliminarily investigated the biomechanical consequences of these various medial patellar stabilizing procedures. Despite this, no existing study has included multiple medial patellofemoral complex (MPFC) reconstructions and assessment of lateral patellar translation at distinct flexion angles. Combined MPFL/MQTFL reconstruction would restore patellofemoral contact areas, forces, and kinematics closest to the native state compared with isolated reconstruction of the MPFL or MQTFL alone. Controlled laboratory study. Ten adult cadaveric knee specimens were prepared and analyzed under 5 different conditions: (1) intact state, (2) transected MPFC, (3) isolated MPFL reconstruction, (4) isolated MQTFL reconstruction, and (5) combined MPFL/MQTFL reconstruction. Patellar tilt, lateral patellar translation, patellofemoral contact forces, and patellofemoral contact areas were measured in each condition from 0° to 80° through simulated knee flexion using a custom servohydraulic load frame with pressure sensor technology and a motion capture system for kinematic data acquisition. The isolated MPFL, isolated MQTFL, and combined MPFL/MQTFL reconstruction conditions produced significantly less lateral patellar tilt compared with the transected MPFC state (P < .05). No statistically significant differences were found when each reconstruction technique was compared with the intact state in patellar tilt, lateral patellar translation, contact forces, and contact areas. All 3 reconstruction techniques (isolated MPFL reconstruction, isolated MQTFL reconstruction, and combined MPFL/MQTFL reconstruction) restored native knee kinematics, contact forces, and contact areas without overconstraint. Isolated MPFL reconstruction, isolated MQTFL reconstruction, and combined MPFL/MQTFL reconstruction all restore patellofemoral stability comparable with the intact MPFC state without the overconstraint that could be concerning for increasing risk of patellofemoral arthritis.

Combined Medial Patellofemoral Ligament and Medial Quadriceps Tendon-Femoral Ligament Reconstruction With Single Knotless Anchor

Lateral patellar dislocations represent a common orthopaedic condition in young, active individuals who experience patellar instability. Despite increasing interest in re-creating the natural biomechanics and native knee anatomy when performing medial patellar soft-tissue reconstructive procedures, there is no consensus among surgeons regarding the best techniques to use when reconstructing the medial patellofemoral ligament and medial quadriceps tendon-femoral ligament. This article details a method to reconstruct the medial patellofemoral ligament and medial quadriceps tendon-femoral ligament using a single graft and a single all-suture knotless anchor on the patella.

Combined Medial Quadriceps Tendon-Femoral Ligament and Medial Patellofemoral Ligament Reconstruction for Revision Patellofemoral Soft-Tissue Stabilization

Patients with recurrent patellofemoral instability in whom prior medial patellofemoral ligament (MPFL) reconstruction fails present unique challenges for revision soft-tissue stabilization owing to scar tissue formation, limited patellar bone stock for anchor placement, and increased risk of patellar fracture. We describe a technique for revision patellofemoral soft-tissue stabilization that combines MPFL and medial quadriceps tendon–femoral ligament reconstruction techniques through combined fixation to the patella with 1 suture anchor and soft-tissue fixation to the quadriceps tendon. The proposed technique maximizes restoration of resistance to lateral translation by attempting to re-create the native MPFL attachment and minimizes patellar fracture risk in the setting of poor bone stock through the use of a single 1.8-mm all-suture suture anchor rather than bone tunnels or multiple anchor placement for bony fixation.

Medial Quadriceps Tendon Femoral Ligament Reconstruction for Anatomic Reconstruction of the Medial Patellofemoral Complex

The medial patellofemoral complex (MPFC) refers to the primary static restraint to lateral patellar translation. Originally thought of as the medial patellofemoral ligament, anatomic studies over the past 10 years have identified the additional fibers that attach to the quadriceps tendon, which some have termed the medial quadriceps tendon femoral ligament. Anatomic studies have demonstrated that the MPFC midpoint is at the junction of the medial border of the quadriceps tendon and the articular surface of the patella, indicating that fixation can be on either structure. This technique describes a single-bundle reconstruction technique with anatomic fixation on the quadriceps tendon at the MPFC midpoint that involves fixation on the extensor mechanism first.

Medial quadriceps tendon femoral ligament reconstruction and medial patellofemoral ligament reconstruction have no significant differences in clinical outcomes for treatment of lateral patellar instability: a matched-cohort study

ObjectivesThe purpose of this study was to compare clinical outcomes of medial quadriceps tendon-femoral ligament reconstruction (MQTFLR) and medial patellofemoral ligament reconstruction (MPFLR) among patients with recurrent lateral patellar instability. MethodsA retrospective matched-cohort study was conducted involving patients who underwent MQTFLR or MPFLR with or without tibial tubercle osteotomy (TTO) from 2019 to 2021. Subjects were matched 1:1 on age, concomitant osteochondral allograft (OCA), concomitant TTO, and follow-up time. Measured outcomes included 90-day complications, Visual Analog Scale (VAS) knee pain, return to sport/work, Kujala score, Tegner score, and MPFL-Return to Sport after Injury (MPFL-RSI) score. Outcomes were compared between groups using Mann–Whitney U-test for continuous variables and Fisher's exact test for categorical variables. P-values <0.05 were considered significant. ResultsTen MQTFLR patients (mean age 28.7 years, 80% female, mean follow-up 19.7 months) and ten MPFLR patients (mean age 29.1 years, 90% female, mean follow-up 28.3 months) were included in the study. One MQTFLR patient (10%) and three MPFLR patients (30%) underwent reoperation for postoperative arthrofibrosis. Postoperative VAS resting pain was not significantly different between the groups (MQTFLR mean 1.1, MPFLR mean 0.6, p ​= ​0.31). There were no significant differences in rates of recurrent subluxations (MQTFLR 20%, MPFLR 0%, p ​= ​0.47), return to sport (MQTFLR 50%, MPFLR 75%, p ​= ​0.61), return to work (MQTFLR 100%, MPFLR 88%, p ​= ​1.00), or MPFL-RSI pass rate (MQTFLR 75% vs. MPFLR 38%, p ​= ​0.31). ConclusionThere were no significant differences in knee pain and function, return to work, and rates of recurrent patellar instability between patients who underwent MQTFLR versus MPFLR, though these results should be interpreted with caution given the small sample size and potential selection bias. Level of EvidenceIII.

Medial Patellofemoral Complex Reconstruction (Combined Reconstruction of Medial Patellofemoral Ligament and Medial Quadriceps Tendon–Femoral Ligament) With Semitendinosus Autograft Resulted in Similar Clinical and Radiographic Outcomes to Medial Patellofemoral Ligament Reconstruction in Treating Recurrent Patellar Dislocation

PurposeTo compare clinical and radiographic outcomes of medial patellofemoral ligament reconstruction (MPFL-R) and medial patellofemoral complex reconstruction (MPFC-R) for recurrent patellar dislocation. Outcome measures were compared based on the Insall–Salvati index. MethodsPatients who were diagnosed with recurrent patellar dislocation and underwent either MPFL-R or MPFC-R (combined reconstruction of MPFL and medial quadriceps tendon-femoral ligament) were retrospectively analyzed. Group allocation was based on surgical procedure and patient characteristics were collected. Clinical assessments included patient-reported outcome measures (PROMs) and return-to-sports rates. Minimal clinically important difference analysis was performed. A subgroup analysis of PROMs was carried out between patients with an Insall–Salvati index ≤1.2 versus >1.2. The patellar tilt angle, lateral patellar displacement, and bisect offset ratio were measured pre- and postsurgery. Functional failures and complications were assessed. ResultsOverall, 70 patients (72 knees) in the MPFL-R group and 58 patients (61 knees) in the MPFC-R group were included. Patient characteristics were comparable between the groups. At a minimum follow-up of 24 (mean, 50.6 ± 22.1) months, all PROMs were substantially improved (P < .001), without significant intergroup differences. The percentages of patients reaching the minimal clinically important difference were similar after MPFL-R and MPFC-R: 98.6% versus 93.4% (International Knee Documentation Committee), 97.2% versus 98.4% (Lysholm), 98.6% versus 100% (Kujala), and 77.8% versus 72.1% (Tegner). The subgroup analysis based on patellar height and the return-to-sport rates also suggested comparable results. Radiographic evaluation demonstrated significantly smaller lateral patellar displacements (P = .004) and bisect offset ratios (P < .001) but similar patellar tilt angles after MPFC-R. Four (5.6%) patients receiving MPFL-R and 2 (3.3%) patients receiving MPFC-R reported recurrence of functional instability, without statistically significant difference. ConclusionsMPFC-R resulted in similar overall clinical and radiographic outcomes to MPFL-R in treating recurrent patellar dislocation. MPFC-R might not provide additional benefits for patients with an Insall-Salvati index >1.2. Level of EvidenceLevel IV, therapeutic, retrospective cohort study.

Medial Patellofemoral Reconstruction Techniques for Patellar Instability

The medial patellofemoral complex (MPFC) is the term used to describe the primary soft tissue stabilizer of the patella, which consists of fibers that attach to the patella (medial patellofemoral ligament, or MPFL), and the quadriceps tendon (medial quadriceps tendon femoral ligament, or MQTFL). Despite the variability of its attachment on the extensor mechanism, the midpoint of this complex is consistently at the junction of the medial quadriceps tendon with the articular surface of the patella, indicating that either patellar or quadriceps tendon fixation can be used for anatomic reconstruction. Multiple techniques exist to reconstruct the MPFC, including graft fixation on the patella, quadriceps tendon, or both structures. Various techniques using several graft types and fixation devices have all reported good outcomes. Regardless of the location of fixation on the extensor mechanism, elements critical to the success of the procedure include anatomic femoral tunnel placement, avoiding placing undue tension on the graft, and addressing concurrent morphological risk factors when present. This infographic reviews the anatomy and techniques for the reconstruction of the MPFC, including graft configuration, type, and fixation, while addressing common pearls and pitfalls in the surgical treatment of patellar instability.

Localization of the Adductor Tubercle in the Skeletally Immature: A Computed Tomography Study With Patellofemoral Surgical Implications

Background: The adductor tubercle of the distal femur is utilized by surgeons as an anatomic landmark to identify graft anchor placement during medial patellofemoral ligament (MPFL) and medial quadriceps tendon femoral ligament (MQTFL) reconstruction for patellofemoral instability. In the skeletally immature population, its location relative to the physis has not been well defined. Purpose: To identify the location of the adductor tubercle relative to the distal femoral physis in skeletally immature individuals and gain insight regarding optimal graft anchor placement for pediatric patients undergoing MPFL and MQTFL reconstruction. Study Design: Descriptive laboratory study. Methods: Thin-cut computed tomography scans of 37 male cadaveric specimens (age, 4-16 years) were obtained from the New Mexico Decedent Image Database. A measurement protocol to identify the adductor tubercle was created with guidance from a fellowship-trained musculoskeletal radiologist. By utilizing axial, coronal, and sagittal views of knee computed tomography scans, the adductor magnus tendon was identified and followed distally to its insertion (adductor tubercle) on the distal femur. Distance from the midpoint of the adductor magnus tendon insertion relative to the physis in the proximal-distal orientation was measured. The anterior-posterior distance of the midpoint tendon insertion relative to the posterior femoral cortex line was also evaluated. Results: The midpoint of the adductor magnus tendon was at the physis in 30 specimens. One 8-year-old cadaveric specimen had an insertion 1.1 mm distal to the physis. In all specimens ≥15 years old (n = 6), the adductor magnus tendon insertion was distal to the physis with a mean distance of 2.73 mm. The location of the adductor tubercle was always posterior (mean, 5.1 mm) with respect to the posterior femoral cortex line. Conclusion: The location of the adductor tubercle in male pediatric patients is likely at or distal to the physis. Thus, the findings of this study directly conflict with previous studies that suggested a more proximal location. Clinical Relevance: Optimal graft anchor placement during MPFL and MQTFL reconstruction in the skeletally immature patient can be challenging because of the variability reported in previous studies of the medial patellofemoral complex origin relative to the physis. This study suggests that distal—rather than proximal—graft anchor placement might better help restore patellofemoral isometry.

Double-Bundle Quadriceps Tendon Autograft for Reconstruction of the Medial Patellofemoral Complex to Manage Recurrent Patellar Dislocation in Patients With Open Physes

Management of chronic patellar instability in patients with open physis requires special reconstruction techniques to minimize the risks of femoral growth plate injury due to the close proximity of the open physis to the native femoral origin of the medial patellofemoral ligament (MPFL). Children and adolescents have a relatively smaller patella than the adult group, so, there is a higher risk of patellar fracture when tunnels are performed in the patella. It is wise to mimic the normal anatomy of the medial patellofemoral complex (MPFC) by reconstruction of both of the medial quadriceps tendon femoral ligament (MQTFL) and MPFL, so as to restore the normal fan-shaped MPFC, with its wide anterior attachment to both of the patella and quadriceps tendon (QT). This article describes a simple, safe, reproducible, and cost effective technique for surgical management of chronic patellar instability in patients with open physis by reconstruction of the MPFC using a double-bundle QT autograft.

Combined Medial Patellofemoral Ligament, Medial Quadriceps Tendon-Femoral Ligament, and Medial Patellotibial Ligament Reconstruction for Patellar Instability: A Technical Note

Lateral patellar dislocations often occur in a young, athletic population of recurrent dislocators with generalized laxity and an interest in returning to an active lifestyle. A recent appreciation for the distal patellotibial complex has directed surgeons toward attempting to re-create the native anatomy and knee biomechanics during medial patellar reconstructive procedures. By reconstructing the medial patellotibial ligament (MPTL) in addition to the medial patella-femoral ligament (MPFL) and medial quadriceps tendon-femoral ligament (MQTFL), the current article describes a potentially more stable construct that can be utilized in patients with subluxation with the knee in full extension, patellar instability with the knee in deep flexion, genu recurvatum, and generalized hyperlaxity. Additionally, the current technique utilizes a tibialis anterior allograft. The purpose of this Technical Note is to describe, in detail, the current authors' technique for a combined MPFL, MQTFL, and MPTL reconstruction.

Combined Reconstruction of the Medial Patellofemoral Ligament and Medial Quadriceps Tendon Femoral Ligament in Skeletally Immature Patients

The medial patellofemoral ligament (MPFL) reconstruction is challenging in skeletally immature patients due to the anatomical particularities at this age. Recently, the medial quadriceps tendon femoral ligament (MQTFL) has received great interest for its ability to restrain the patella’s instability along with MPFL. No gold-standard technique has been described so far to reconstruct both MPFL and MQTFL in skeletally immature patients. We present a technique to safely reconstruct the MPFL and the MQTFL in children and adolescents. The gracilis tendon autograft is harvested and passed through the medial collateral ligament as a pulley. The free ends of the graft are passed through the patella by an “L-shaped tunnel” and tied to itself. The other free end of the graft is pulled through the medial third of the quadriceps tendon and tied to itself to achieve tension. Our technique is reproducible, implant-free and avoids complications associated with femoral drilling and graft fixation. However no long-term follow-up results are available.

Biomechanical Comparison of 3 Medial Patellofemoral Complex Reconstruction Techniques Shows Medial Overconstraint but No Significant Difference in Patella Lateralization and Contact Pressure

The purpose of this study was to investigate biomechanical differences of medial patellofemoral ligament (MPFL) reconstruction, medial quadriceps tendon femoral ligament (MQTFL) reconstruction, and a combination of these techniques to restore lateral patellar constraint and contact pressures. Eight fresh frozen cadaver knees were mounted to a custom jig with physiological quadriceps tendon loading. Flexion angles and contact pressure (CP) were dynamically measured using Tekscan® pressure sensors and Polhemus® Liberty 6 degree of freedom (6DOF) positioning sensors in the following conditions: 1) intact 2) MPFL and MQTFL deficient, 3) MPFL reconstructed, 4) Combined MPFL+ MQTFL reconstructed, and 5) MQTFL reconstructed. Lateral patellar translation was tested using horizontally directed 30 N force applied at 30° of knee flexion. The knees were flexed in dynamic fashion, and CP values were recorded for 10°, 20°, 30°, 50°, 70°, and 90° degrees of flexion. Group differences were assessed with ANOVA's followed by pairwise comparisons with Bonferroni correction. MPFL (P= .002) and combined MPFL/MQTFL (P= .034) reconstruction significantly reduced patellar lateralization from+19.28% (9.78%, 28.78%) in the deficient condition to-17.57% (-27.84%,-7.29%) and-15.56% (-33.61%, 2.30%), respectively. MPFL reconstruction was most restrictive and MQTFL reconstruction the least-7.29% (-22.01%, 7.45%). No significant differences were found between the three reconstruction techniques. Differences in CP between the three reconstruction techniques were not significant (<.02 MPa) at all flexion angles. The present study found no significant difference for patellar lateralization and patellofemoral CP between MPFL, combined MPFL/MQTFL, and MQTFL reconstruction. All 3 techniques resulted in stronger lateral patellar constraint compared to the native state, while the MQTFL reconstruction emulated the intact state the closest. Various surgical techniques for medial patellofemoral complex reconstruction can restore patellar stability with similar patellofemoral articular pressures.

Quantifying the Relationship Between the Medial Quadriceps Tendon–Femoral Ligament and Patellar Borders: A Pediatric Cadaveric Study

Background: The medial patellofemoral complex (MPFC) is a structure composed of the medial quadriceps tendon–femoral ligament (MQTFL) superiorly and the medial patellofemoral ligament (MPFL) inferiorly. The pediatric MPFL anatomy has been well described, but the precise anatomy of the MQTFL has only recently been described and studied in skeletally immature patients. Purpose: To describe the anatomic relationship between the MQTFL and its insertion on the quadriceps tendon and patella in pediatric specimens. Study Design: Descriptive laboratory study. Methods: A total of 22 pediatric cadaveric knee specimens were dissected to analyze attachment of the MQTFL to the quadriceps tendon and patella. Dissection was facilitated using lateral parapatellar arthrotomy followed by eversion of the extensor mechanism to evaluate MQTFL fibers from its undersurface. Results: The mean specimen age was 7.4 years. Specimens were divided based on age into a younger cohort (1-2 years), middle cohort (4-8 years), and older cohort (9-12 years). The quadriceps tendon attachment (QTA) of the MQTFL proximal to the patella extended a median of 5.0 mm in the younger cohort, 11.4 mm in the middle cohort, and 12.0 mm in the older cohort, with significant differences found between the younger and middle cohorts (P < .047) and the younger and older cohorts (P < .001). The QTA as a percentage of patellar articular height averaged 44.4% across all specimens. The vertical height of the patella measured a median of 14.0 mm, 22.3 mm, and 27.3 mm in the younger, middle, and older cohorts, respectively. Conclusion: This study expands on the recently described anatomy of the pediatric MPFC to quantify the anatomic relationship between the MQTFL attachment to the quadriceps tendon and patella in a more clinically relevant cohort of donor specimens. Clinical Relevance: As access to pediatric cadaveric tissue is extremely limited, a better understanding of MPFC and MQTFL anatomy will support surgeons in preoperative planning and intraoperative considerations for their approach to MQTFL and MPFL reconstruction. This may facilitate improved anatomic surgical stabilization of the patellofemoral joint in pediatric patients.

Simultaneous Medial Patellofemoral Ligament and Medial Quadriceps Tendon–Femoral Ligament Reconstructions Using an Artificial Ligament for Lateral Patella Instability

Recent studies on the detailed anatomy of the medial patellar stabilizer have revealed that the medial patellofemoral ligament (MPFL) not only attaches to the patella but also has fibers that attach to the quadriceps muscle, known as the medial quadriceps tendon femoral ligament (MQTFL). Reconstruction of the medial stabilizer for patellar dislocation that includes both the MPFL and MQTFL may achieve better anatomical and physiological correction. In this Technical Note, we will describe a simultaneous reconstruction technique of the MPFL and MQTFL for patellar dislocation using an artificial ligament.

Quantifying the Relationship Between the Medial Patellofemoral Complex and Patellar Borders: A Pediatric Cadaveric Study

Background:The medial patellofemoral complex (MPFC) is comprised of the medial quadriceps tendon-femoral ligament (MQTFL) superiorly and the medial patellofemoral ligament (MPFL) inferiorly. The anatomy of the pediatric MPFL has been well-described, however, the MPFC in skeletally immature patients and its relationship to the quadriceps tendon and superior patellar border has yet to be described.Purpose:To evaluate the relationship between the MPFC attachment and quadriceps tendon and patella in skeletally immature patients.Methods:16 pediatric knees were dissected to analyze the MPFC insertion on the quadriceps tendon. Dissection was performed using a lateral parapatellar arthrotomy followed by eversion of the extensor mechanism to evaluate the MPFC fibers from its undersurface. The patellar articular length (PL), patellar width, and quadriceps tendon attachment (QTA) of the MPFC above the superior pole of the patella were measured using the ImageJ program. Additionally, the ratio of quadriceps tendon attachment to patellar length was calculated as a percent (QTA/PL%). Two sample t-tests were used to identify significant differences.Results:The average age of the specimens included in this study was 9.6 years. Specimens were divided into two cohorts: a younger cohort (4-8 years), and an older cohort (9-12 years). The QTA above the patella averaged 10.6 mm in the younger cohort and 13.4 mm in the older cohort with no significant difference between the two groups (Figure 1). There was no significant difference in average QTA/PL% which was found to be 47.8% and 48% for the younger and older cohorts respectively (Figure 1). PL was significantly longer in the older cohort (Figure 1). As shown in Figure 2, the insertion of the proximal MPFC into the quadriceps tendon can be variable across specimens.Conclusion:This study clarifies the anatomy of the pediatric MPFC in exceptionally rare pediatric specimens. The MQTFL relationship to the quadriceps tendon is important to guide surgical reconstructions of the medial stabilizers of the patellofemoral joint. Primary and recurrent patella instability remains a significant problem in those under 20 years. A better understanding of the MPFC (both the MQTFL and MPFL components) will support anatomic reconstructions to stabilize the joint.Figure 1:QTA, PL, and QTA/PL% for individual specimens.Figure 2:MPFC Insertion into the Quadriceps Tendon.

Technique Variation for MPFL Reconstruction in Skeletally Immature Patients: Data from the Jupiter Cohort

Background:Management approaches and surgical techniques, when applied for pediatric and adolescent patellofemoral instability (PFI), continue to lack clear clinical guidelines and indications. Medial patellofemoral ligament reconstruction (MFPLR) is among the most popular surgical options. However, variation in technique remains significant, particularly in skeletally immature sub-populations.Purpose:The purpose of this study was to examine the variation in MPFLR technique in skeletally immature patients within a cohort of 20 orthopedic surgeons with different experience levels and specialty training backgrounds. Methods: All operative records of skeletally immature patients from 2016 to 2021 were retrieved from the JUPITER cohort, a multi-center prospective study involving 13 different tertiary care academic centers. Patients who underwent a primary single-stage MPFLR were evaluated in this study. Demographic information and operative details were collected for each knee.Results:Of the 306 knees, 205 (53% female, 47% male) met inclusion criteria and comprised the final cohort (Table 1). The average age was 13.6 ± 1.8 yrs (5.1-19.0). The initial injury mechanism was of a non-contact nature in 73% and a result of contact in 17%. 47% of surgeons utilized autograft while 53% utilized allograft. Suture anchors (including small tenodesis screws) were the most popular patellar fixation technique (61%), followed by the use of tunnel under a bone bridge (37%). The majority of surgeons utilized 2 suture anchors (59%). Interference screws were the most popular femoral fixation technique (84%), followed by suture anchors (12%). The majority of surgeons used either 1 interference screw 97(%) or 1 suture anchor at the femur (96%). In addition to MPFLR, 15% of patients underwent osteochondral fracture treatment: 36% underwent loose body removal, while 61% underwent fixation. Lateral Retinacular Release was performed in 13% of cases, and lateral retinacular lengthening was performed in 2%. 10% of patients underwent concomitant hemi-epiphysiodesis for genu valgum, 3% underwent medial quadriceps tendon-femoral ligament reconstructions, and 3% underwent a Grammont realignment (patellar tendon medialization) procedure.Conclusion:Variation in different aspects of MPFLR technique is substantial among this cohort of orthopedic surgeons. Given the well-established importance of decreasing variation for healthcare cost containment and optimization of outcomes, comparative studies and sub-stratified analyses are needed to better elucidate the most favorable techniques and their components.Table 1.Demographic and Surgical Data

Radiographic Landmarks for the Femoral Attachment of the Medial Patellofemoral Complex: A Cadaveric Study

To report the radiographic landmarks for the medial patellofemoral complex (MPFC) footprint on the medial femur and describe the difference between the radiographic positions corresponding to the medial quadriceps tendon femoral ligament (MQTFL) and medial patellofemoral ligament (MPFL) fibers. In 8 unpaired cadaveric knees, the MPFC footprint was exposed on the medial femur, and the proximal and distal boundaries of the footprint were marked. Lateral fluoroscopic images of the knee were obtained and analyzed using Image J. The proximal boundary corresponding to the MQTFL, the MPFC midpoint, and distal boundary corresponding to the MPFL were described radiographically and compared for differences in position. The proximal MQTFL footprint was 0.8 ± 0.6 mm anterior (P= .013) and 5.2 ± 1.8 mm proximal to the MPFC midpoint (P <.001), whereas the distal MPFL footprint was 0.8 ± 0.7 mm posterior (P= .012) and 5.9 ± 1.1 mm distal to the radiographic MPFC midpoint (P <.001). The radiographic point corresponding to the distal MPFL footprint was 0.8 ± 0.9 mm posterior (P= .011) and 11.1 ± 2.3 mm distal to the radiographic point of the proximal MQTFL footprint (P <.001). When using the point of intersection of the posterior cortical line and the proximal posterior condyle as a reference, 91.6% of all points correlating to the MQTFL, MPFC midpoint and MPFL, were within 10 mm in any direction from this radiographic landmark. On fluoroscopic imaging, the proximal MQTFL and distal MPFL fibers had significantly different radiographic positions from the MPFC midpoint on the femur. These findings should be considered when reconstructing specific components of the MPFC. As fluoroscopy is often used intraoperatively to guide graft placement, our findings may serve as a reference when differentiating the locations of the MPFL vs MQTFL on the femur for anatomic reconstruction.

Medial Patellofemoral Complex Reconstruction Techniques Are Not Equivalent at Lower Flexion in the Setting of Patella Alta: A Biomechanical Comparison

To (1) determine the effect of severe patella alta on lateral patellar displacement after medial patellofemoral ligament (MPFL) reconstruction and medial quadriceps tendon-femoral ligament (MQTFL) reconstruction and (2) determine whether lateral displacement significantly differs between MPFL and MQTFL reconstructions in the setting of severe patella alta (Caton-Deschamps Index [CDI] of 1.6). Eight cadaveric specimens were included. High-tensile strength suture was used to create a model of adjustable patellar height. Patellar height was set using fluoroscopy to CDI ratios of 1.0 (normal) and 1.6 (alta). Specimens underwent testing (1) with MPFL reconstruction, (2) with MQTFL reconstruction, and (3) in a medial patellofemoral complex (MPFC)-deficient control state, in randomized order, at both CDI settings: 1.0 and 1.6. Lateral patellar translation was measured at 0°, 10°, 20°, 30°, 45°, 60°, and 90° of knee flexion with 10 N of laterally directed load. At a CDI of 1.6, MPFL reconstruction showed significantly lower lateral displacement than MQTFL reconstruction at 0° and 20°. When compared with MPFC-deficient controls at a CDI of 1.6, MPFL reconstruction showed significantly lower displacement at 0° and 20° whereas MQTFL reconstruction was not significantly different at any degree of flexion. In the setting of severe patella alta (CDI of 1.6), MPFL reconstruction results in less lateral patellar displacement than MQTFL reconstruction at 0° and 20° of knee flexion. At higher flexion angles (≥30°), there is no difference between the 2 reconstruction techniques and the CDI no longer has an effect. At a CDI of 1.0, MPFL reconstruction shows lower displacement than MQTFL reconstruction in full extension only. Surgeons performing MPFC reconstruction should evaluate patients for patella alta and consider patellar height when deciding on the reconstruction technique. This study suggests that MQTFL reconstruction may be less stable than MPFL reconstruction in the setting of patella alta, without other known pathoanatomic factors, at early knee flexion angles. Patellar height should be considered when choosing the appropriate reconstruction technique in the absence of a distalization procedure.

Rehabilitation and Return to Sport After Medial Patellofemoral Complex Reconstruction

AbstractThe medial patellofemoral complex (MPFC) consists of the medial patellofemoral ligament and medial quadriceps tendon femoral ligament, which play a critical role stabilizing the patella against lateral translation. After a patellar dislocation, athletes with recurrent dislocations have functional limitations that may limit their return to their prior level of competition, requiring surgical reconstruction. Although ample literature exists delineating return-to-play (RTP) considerations after anterior cruciate ligament reconstruction, there is a paucity of evidence specific to MPFC reconstruction. Athletes aiming to return to sport after MPFC reconstruction require the same methodical treatment approach to ensure safe RTP. A criterion-based periodical assessment of progress that measures range of motion, strength, neuromuscular control, balance, agility, and power are pivotal components of rehabilitating this population. A combination of objective and subjective criteria should be assessed when determining an individual’s readiness for sports-specific activities. A battery of functional tests, including quadriceps strength testing, single-limb hop testing, lateral step-down test, the lateral leap and catch test, the Y-balance test, and the depth jump should be considered when evaluating the athlete for readiness for sport, incorporating specific understanding of the biomechanics of the patellofemoral joint. We discuss the considerations for return-to-sport rehabilitation and testing after MPFC reconstruction, to provide clinicians working with an athletic population a framework to adequately prepare their athletes for safe return to sport.

Complex Patellofemoral Reconstruction for Recurrent Instability

Background: Patellofemoral instability is due to a combination of bony and soft tissue factors. While recurrent patellar dislocations are rare, evaluation and treatment of these conditions require addressing patellar height and lateralization of the tibial tubercle (TT), restraint to lateral patellar subluxation, and trochlear dysplasia. Other factors to consider are coronal limb-length alignment outside of the physiologic 5 to 8° of valgus, which may significantly alter the Q angle and contribute to lateral instability. Other ligaments around the patella contribute to soft-tissue restraint, including the medial and lateral patellotibial ligaments, patellomeniscal ligaments, and the medial quadriceps tendon femoral ligament. Patellar tilt is assessed with and without quadriceps contraction to further evaluate the patella’s relationship to the trochlear groove. The Caton-Deschamps Index, as well as patellar trochlear index (PTI), are used to measure patellar height for patella alta or baja. Technique Description: The technique is to surgically manage a patient in neutral mechanical alignment on standing limb radiographs, with moderate-to-severe DeJour type B trochlear dysplasia and a trochlear sulcus angle of around 145°, patella alta with a Caton-Deschamps Index of 1.6 and PTI of 0.22, a TT to trochlear groove (TT-TG) distance of 8 mm, and a deficient medial patellofemoral ligament (MPFL). The MPFL reconstruction is done first, with harvesting of the ipsilateral quadriceps tendon and maintenance of its distal attachment on the superior patellar pole. The quadriceps tendon graft is folded medially upon its distal attachment and fixed in this position with suture anchors. Tibial tubercle osteotomy is accomplished by spacing drill holes 2 mm apart, medially and laterally, on the TT and connecting the drill holes with an osteotome and reciprocating saw. A distalized location to secure the TT is selected and superficial bone is excised. A medial parapatellar arthrotomy is performed, and bur attachments are used to drill into the subchondral bone beneath the femoral articular surface to create a V-shaped flap of trochlear cartilage. An arthroscope is inserted under the trochlear flap during this process to visualize the appropriate depth. The trochlear flap is then secured with screws passed over guide pins to secure the flap to the desired location. Cannulated screws and washers are then used to secure the TT to its distalized and/or medialized position, with fluoroscopic verification of screw depth and location. The arthrotomy is then closed with the knee at 45°. The quadriceps graft is passed through a subretinacular channel and secured with suture anchors, adjacent to the adductor tubercle, to complete the MPFL reconstruction. Before closure, appropriate tracking and translation of the patella is verified. Results: Sulcus-deepening trochleoplasty, with or without MPFL reconstruction, has been reported to obtain satisfactory outcomes at 2 years, with close to 85% return to sport and 100% return to work, with improvements in International Knee Documentation Committee (IKDC) scores from 50.8 to 79.1 in some studies. MPFL reconstruction with tibial tubercle osteotomy (TTO) has yielded a 94.5% patient satisfaction rate in the literature. Discussion/Conclusion: In patients with recurrent patellar instability and DeJour types B-D trochlear dysplasia, MPFL reconstruction with TTO and sulcus-deepening trochleoplasty provides excellent subjective outcomes and restores patellar tracking with elimination of recurrent subluxation.