Deep Medial Collateral Ligament Research Articles

Specific tibial landmarks to improve to accuracy of the tibial cut during total knee arthroplasty. A case control study.

More personalized alignment techniques in total knee arthroplasty (TKA) have recently been described particularly for the young and active patients. Performing the ideal tibial cut might be challenging with a conventional ancillary. Therefore the aims of this study were: (1) to describe specific tibial landmarks to optimize the tibial cut in TKA; (2) to compare the accuracy of the tibial cut with these landmarks compared to a conventional technique. This retrospective case-control study compared primary TKAs performed using a conventional technique with extramedullary guide associated with specific tibial landmarks. For each case, one control patient was matched based on body mass index (BMI), age, preoperative Hip Knee Ankle (HKA) angle, and Medial Proximal Tibial Angle (MPTA). All control patients were operated by the same surgeon and similar conventional technique but without landmarks. The MPTA target was to reproduce preoperative deformity with a 3° of varus limit. 34 TKA were included in each group. There was no preoperative difference between both groups. Mean age was 63years old ± 8. Mean BMI was 32kg/m2 ± 5. Mean HKA was 170.6° ± 2.5. Mean MPTA was 85.1° ± 2.3. The radiographic assessment was performed preoperatively and at 2months: HKA, mechanical Medial Distal Femoral Angle (mMDFA), MPTA, tibial slope, restoration of the joint line-height. The tibial landmarks corresponded to the line of insertion of the deep medial collateral ligament fibers extended to the capsular insertion above the Gerdy tubercle. The postoperative MPTA was significantly more varus (87.2° ± 1.6 in landmark group versus 88.3° ± 2.2; p = 0.027) and closer to preoperative bone deformity in landmark group (p = 0.002) with significantly less outliers than in the conventional group. There was no significant difference between both groups postoperatively for HKA (175.4° ± 2.3 versus 175.9° ± 2.5; p = 0.42); mMDFA (88.9° ± 2.3 versus 88.2° ± 2.1; p = 0.18); tibial slope (82.6° ± 1.9 versus 82.4° ± 2.6; p = 0.67), the restoration of the joint line-height (1.5mm ± 2 versus 1.8mm ± 2; p = 0.56). Specific tibial landmarks during TKA can be used to increase the accuracy of the tibial cut when using personalized alignment techniques in TKA. IV.

Load Sharing of the Deep and Superficial Medial Collateral Ligaments, the Effect of a Partial Superficial Medial Collateral Injury, and Implications on ACL Load

Background: Injuries to the deep medial collateral ligament (dMCL) and partial superficial MCL (psMCL) can cause anteromedial rotatory instability; however, the contribution of each these injuries in restraining anteromedial rotatory instability and the effect on the anterior cruciate ligament (ACL) load remain unknown. Purpose: To investigate the contributions of the different MCL structures in restraining tibiofemoral motion and to evaluate the load through the ACL after MCL injury, especially after combined dMCL/psMCL injury. Study Design: Controlled laboratory study. Methods: Sixteen fresh-frozen human cadaveric knees were tested using a 6 degrees of freedom robotic simulator. Tibiofemoral kinematic parameters were recorded at 0°, 30°, 60°, and 90° of knee flexion for the following measurements: 8-N·m valgus rotation, 4-N·m external tibial rotation (ER), 4-N·m internal tibial rotation, and a combined 89-N anterior tibial translation and 4-N·m ER for both anteromedial rotation (AMR) and anteromedial translation (AMT). The kinematic parameters of the 3 different MCL injuries (dMCL; dMCL/psMCL; dMCL/superficial MCL (sMCL)) were recorded and reapplied either in an ACL-deficient joint (load sharing) or before and after cutting the ACL (ACL load). The loads were calculated by applying the principle of superposition. Results: The dMCL had the largest effect on reducing the force/torque during ER, AMR, and AMT in extension and the psMCL injury at 30° to 90° of knee flexion (P < .05). In a comparison of the load through the ACL when the MCL was intact, the ACL load increased by 46% and 127% after dMCL injury and combined dMCL/psMCL injury, respectively, at 30° of knee flexion during ER. In valgus rotation, a significant increase in ACL load was seen only at 90° of knee flexion. Conclusion: The psMCL injury made the largest contribution to the reduction of net force/torque during AMR/AMT at 30° to 90° of flexion. Concomitant dMCL/psMCL injury increased the ACL load, mainly during ER. Clinical Relevance: If a surgical procedure is being considered to treat anteromedial rotatory instability, then the procedure should focus on restoring sMCL function, as injury to this structure causes a major loss of the knee joint’s capacity to restrain AMR/AMT.

Effect of a Partial Superficial and Deep Medial Collateral Ligament Injury on Knee Joint Laxity.

Injuries to the medial collateral ligament (MCL), specifically the deep MCL (dMCL) and superficial MCL (sMCL), are both reported to be factors in anteromedial rotatory instability (AMRI); however, a partial sMCL (psMCL) injury is often present, the effect of which on AMRI is unknown. To investigate the effect of a dMCL injury with or without a psMCL injury on knee joint laxity. Controlled laboratory study. Sixteen fresh-frozen human cadaveric knees were tested using a 6 degrees of freedom robotic simulator. The anterior cruciate ligament (ACL) was cut first and last in protocols 1 and 2, respectively. The dMCL was cut completely, followed by an intermediary psMCL injury state before the sMCL was completely sectioned. Tibiofemoral kinematics were measured at 0°, 30°, 60°, and 90° of knee flexion for the following measurements: 8 N·m of valgus rotation (VR), 4 N·m of external tibial rotation, 4 N·m of internal tibial rotation, and combined 89 N of anterior tibial translation and 4 N·m of external tibial rotation for both anteromedial rotation (AMR) and anteromedial translation. The differences between subsequent states, as well as differences with respect to the intact state, were analyzed. In an ACL-intact or -deficient joint, a combined dMCL and psMCL injury increased external tibial rotation and VR compared with the intact state at all angles. A significant increase in AMR was seen in the ACL-intact knee after this combined injury. Cutting the dMCL alone showed lower mean increases in AMR compared with the psMCL injury, which were significant only when the ACL was intact in knee flexion. Moreover, cutting the dMCL had no effect on VR. The ACL was the most important structure in controlling anteromedial translation, followed by the psMCL or dMCL depending on the knee flexion angle. A dMCL injury alone may produce a small increase in AMRI but not in VR. A combined dMCL and psMCL injury caused an increase in AMRI and VR. In clinical practice, if an increase in AMRI at 30° and 90° of knee flexion is seen together with some increase in VR, a combined dMCL and psMCL injury should be suspected.

A Comparative Biomechanical Study of Alternative Medial Collateral Ligament Reconstruction Techniques

Background: There is little evidence of the biomechanical performance of medial collateral ligament (MCL) reconstructions for restoring stability to the MCL-deficient knee regarding valgus, external rotation (ER), and anteromedial rotatory instability (AMRI). Hypothesis: A short isometric reconstruction will better restore stability than a longer superficial MCL (sMCL) reconstruction, and an additional deep MCL (dMCL) graft will better control ER and AMRI than single-strand reconstructions. Study Design: Controlled laboratory study. Methods: Nine cadaveric human knees were tested in a kinematics rig that allowed tibial loading while the knee was flexed-extended 0° to 100°. Optical markers were placed on the femur and tibia and displacements were measured using a stereo camera system. The knee was tested intact, and then after MCL (sMCL + dMCL) transection, and loaded in anterior tibial translation (ATT), ER, varus-valgus, and combined ATT + ER (AMRI loading). Five different isometric MCL reconstructions were tested: isolated long sMCL, a short construct, each with and without dMCL addition, and isolated dMCL reconstruction, using an 8 mm–wide synthetic graft. Results: MCL deficiency caused an increase in ER of 4° at 0° of flexion (P = .271) up to 14° at 100° of flexion (P = .002), and valgus laxity increased by 5° to 8° between 0° and 100° of flexion (P < .024 at 0°-90°). ATT did not increase significantly in isolated MCL deficiency (P > .999). All 5 reconstructions restored native stability across the arc of flexion apart from the isolated long sMCL, which demonstrated residual ER instability (P≤ .047 vs other reconstructions). Conclusion: All tested techniques apart from the isolated long sMCL graft are satisfactory in the context of restoring the valgus, ER, and AMRI stability to the MCL-deficient knee in a cadaveric model. Clinical Relevance: Contemporary MCL reconstruction techniques fail to control ER and therefore AMRI as they use a long sMCL graft and do not address the dMCL. This study compares 5 MCL reconstruction techniques. Both long and short isometric constructs other than the long sMCL achieved native stability in valgus and ER/AMRI. Double-strand reconstructions (sMCL + dMCL) tended to provide more stability. This study shows which reconstructions demonstrate the best biomechanical performance, informs surgical reconstruction techniques for AMRI, and questions the efficacy of current popular techniques.

High prevalence of associated injuries in anterior cruciate ligament tears: A detailed magnetic resonance imaging analysis of 254 patients.

To evaluate the type and prevalence of associated injuries by using magnetic resonance imaging (MRI) in patients with anterior cruciate ligament (ACL) tears. Data from the Natural Corollaries and Recovery after ACL injury multicenter longitudinal cohort study were analyzed. Between May 2016 and October 2018, patients aged between 15 and 40years, who had experienced an ACL tear within the last 6weeks and sought medical attention at one of seven healthcare clinics in Sweden, were invited to participate. The mean time from injury to MRI was 19.6 ± 15.2days. An orthopedic knee surgeon and a musculoskeletal radiologist reviewed all the MRI scans. The following structures were assessed: posterior cruciate ligament (PCL), medial collateral ligament (MCL) complex, lateral collateral ligament (LCL), popliteus tendon, medial meniscus (MM), lateral meniscus (LM), and cartilage. In addition, the presence of bone bruising, impaction fractures in the lateral femoral condyle (LFC) or posterolateral tibia (PLT), and Segond fractures were also assessed. RESULTS: A total of 254 patients (48.4% males) with a mean age of 25.4 ± 7.1 years were included. The prevalence of associated injuries was as follows: PCL (0.4%), MCL {41.3% [superficial MCL and deep MCL (dMCL) 16.5%; isolated dMCL 24.8%]}, LCL (2.4%), MM (57.4%), LM (25.2%), cartilage (15.0%), bone bruising (92.9%), impaction fracture in the LFC (45.7%) and PLT (4.7%), and Segond fracture (7.5%). The prevalence of associated injuries in patients with ACL tears was high. The findings reported in this study may serve as a reference tool for orthopedic surgeons and radiologists in the diagnosis of associated injuries using MRI in patients with ACL tears.

Effect of deep medial collateral ligament release during high knee flexion movements

PurposeThe medial preserving gap technique has recently been used in total knee arthroplasty. Generally, the deep medial collateral ligament (DMCL) is released using this technique. However, the effect of DMCL release on the kinematics and length of the ligaments remains unknown. This study aimed to clarify how DMCL release affects the kinematics and length change of the ligaments during high knee flexion movements. MethodsThree cadaveric knees were examined using a computed tomography-based navigation system. The following parameters were evaluated: femoral rotation and varus-valgus angle relative to the tibia; anteroposterior translation of the sulcus distal to the medial epicondyle (medial side) and tip of the lateral epicondyle of the femur (lateral side); mediolateral translation of the medial and lateral sides of the plane perpendicular to the tibial mechanical axis; and kinematic pathways during non-weight-bearing knee flexion, cross-legged motion, and sideways motion. ResultsThere were no significant differences in the kinematics and length change of the ligaments during all movements after DMCL release compared with that before DMCL release. ConclusionDMCL release did not affect the kinematics and length change of the ligaments.

Isometry of anteromedial reconstructions mimicking the deep medial collateral ligament depends on the femoral insertion.

This study aimed to investigate the length change patterns of the native deep medial collateral ligament (dMCL) and potential anteromedial reconstructions (AMs) that might be added to a reconstruction of the superficial MCL (sMCL)to better understand the control of anteromedial rotatory instability (AMRI). Insertion points of the dMCL and potential AM reconstructions were marked with pins (tibial) and eyelets (femoral) in 11 cadaveric knee specimens. Length changes between the pins and eyelets were then tested using threads in a validated kinematics rig with muscle loading of the quadriceps and iliotibial tract. Between 0° and 100° knee flexion, length change pattern of the anterior, middle and posterior part of the dMCL and simulated AM reconstructions were analysed using a rotary encoder. Isometry was tested using the total strain range (TSR). The tibiofemoral distance of the anterior dMCL part lengthened with flexion (+12.7% at 100°), whereas the posterior part slackened with flexion (-12.9% at 100°). The middle part behaved almost isometrically (maximum length: +2.8% at 100°). Depending on the femoral position within the sMCL footprint, AM reconstructions resulted in an increase in length as the knee flexed when a more centred position was used, irrespective of the tibial attachment position. Femoral positioning in the posterior aspect of the sMCL footprint exhibited <4% length change and was slightly less tight in flexion (min TSR = 3.6 ± 1.5%), irrespective of the tibial attachment position. The length change behaviour of potential AM reconstructions in a functionally intact knee is mainly influenced by the position of the femoral attachment, with different tibial attachments having a minimal effect on length change. Surgeons performing AM reconstructions to control AMRI would be advised to choose a femoral graft position in the posterior part of the native sMCL attachment to optimise graft length change behaviour. Given the high frequency of MCL injuries, sufficient restoration of AMRI is essential in isolated and combined ligamentous knee injuries. There is no level of evidence as thisstudy was an experimental laboratory study.

Single-Strand “Short Isometric Construct” Medial Collateral Ligament Reconstruction Restores Valgus and Rotational Stability While Isolated Deep MCL and Superficial MCL Reconstruction Do Not

Background: Historical MCL (medial collateral ligament) reconstruction (MCLR) techniques have focused on the superficial MCL (sMCL) to restore valgus stability while frequently ignoring the importance of the deep MCL (dMCL) in controlling tibial external rotation. The recent recognition of the medial ligament complex importance has multiple studies revisiting medial anatomy and questioning contemporary MCLR techniques. Purpose: To assess whether (1) an isolated sMCL reconstruction (sMCLR), (2) an isolated dMCL reconstruction (dMCLR), or (3) a novel single-strand short isometric construct (SIC) would restore translational and rotational stability to a knee with a dMCL and sMCL injury. Study Design: Controlled laboratory study. Methods: Biomechanical testing was performed on 14 fresh-frozen cadaveric knee specimens using a custom multiaxial knee activity simulator. The specimens were divided into 2 groups. The first group was tested in 4 states: intact, after sectioning the sMCL and dMCL, isolated sMCLR, and isolated dMCLR. The second group was tested in 3 states: intact, after sectioning the sMCL and dMCL, and after single-strand SIC reconstruction (SICR). In each state, 4 loading conditions were applied at 0°, 20°, 40°, 60°, and 90° of knee flexion: 8-N·m valgus torque, 5-N·m external rotation torque, 90-N anterior drawer, and combined 90-N anterior drawer plus 5-N·m tibial external rotation torque. Anterior translation, valgus rotation, and external rotation of the knee were measured for each state and loading condition using an optical motion capture system. Results: sMCL and dMCL transection resulted in increased laxity for all loading conditions at all flexion angles. Isolated dMCLR restored external rotation stability to intact levels throughout all degrees of flexion, yet valgus stability was restored only at 0° of flexion. Isolated sMCLR restored valgus and external rotation stability at 0°, 20°, and 40° of flexion but not at 60° or 90° of flexion. Single-strand SICR restored valgus and external rotation stability at all flexion angles. In the combined anterior drawer plus external rotation test, isolated dMCL and single-strand SICR restored stability to the intact level at all flexion angles, while the isolated sMCL restored stability at 20° and 40° of flexion but not at 60° or 90° of flexion. Conclusion: In the cadaveric model, single-strand SICR restored valgus and rotational stability throughout the range of motion. dMCLR restored rotational stability to the knee throughout the range of motion but did not restore valgus stability. Isolated sMCLR restored external rotation and valgus stability in early flexion. Clinical Relevance: In patients with anteromedial rotatory instability in the knee, neither an sMCLR nor a dMCLR is sufficient to restore stability.

The Inside-Out Technique of Deep Medial Collateral Ligament Release Could Provide Good Visualization during Knee Arthroscopy

During knee arthroscopy, clear vision of the intra-articular structures is essential. Two techniques have been described to aid in visualization by releasing the medial collateral ligament (MCL). The outside-in technique remains the most widely used, but injury to the saphenous nerve is one of the potential risks when performing this technique. On the other hand, the inside-out techniques for releasing the deep MCL (dMCL) tend to be safer since the procedure was done under direct visualization through an anteromedial portal. This study was a retrospective case series of 22 patients who underwent the dMCL release using an inside-out technique. The outcomes reported are medial joint space opening, neurovascular injury, and residual morbidities such as pain and valgus knee instability after the procedure.

QUANTIFYING ANTERIOR MEDIAL ROTATIONAL STABILITY IN ANTERIOR CRUCIATE LIGAMENT-INJURED PATIENTS WITH ASSOCIATED COLLATERAL INVOLVEMENT

IntroductionAnterior tibial translation (ATT) is assessed in the acutely injured knee to investigate for ligamentous injury and rotational laxity. Specifically, there is a growing recognition of the significance of anterior medial rotary laxity (AMRI) as a crucial element in assessing knee stability. Anterior cruciate ligament (ACL) injuries are often accompanied with medial collateral ligament (MCL) damage. It has been suggested that Deep MCL (dMCL) fibres are a primary restraint in rotational displacement. This research aims to quantify the difference in rotational laxity of patients with ACL and MCL injuries to deem if the Feagin-Thomas test can robustly capture metrics of AMRI. 2.MethodsAMRI was assessed using the Feagin-Thomas test in 7 isolated ACL (iACL) injured participants, 3 combined ACL and superficial fibre MCL (sMCL) injuries, 5 combined ACL and deep fibre MCL injuries, and 21 healthy controls. Displacement values were recorded using an optical motion capture (OMC) system and bespoke processing pipeline which map and model the knee's anterior displacement values relative to the medial compartment. Since absolute values (mm) of rotational laxity vary dependant on the person, values were recorded as a proportion of the rotational laxity obtained from the subject's contralateral leg. Values were compared between each patient group using an ANOVA test and Tukey's honesty significant difference post hoc test. 3.ResultsThe healthy control group had a median proportion of 0.97 (3SF), whilst the iACL was 1.12 (3SF), a 12% increase in rotational laxity in the injured leg. The sMCL group yielded a result of 1.64 (3SF), a 64% increase in rotational laxity in the injured leg; finally, dMCL resulted in a proportion of rotational laxity of 1.90 (3SF), a 90% increase in rotational laxity [table 1]. Whilst all groups showed differences in the increase of rotational laxity, dMCL was significantly different from the healthy control group (P value 0.0041). 4.ConclusionACL injuries with MCL involvement led to an increase in anterior medial rotary laxity and this is more evident in patients where deep MCL fibres are involved. The Feagin-Thomas test appears to be sensitive in detecting differences in AMRI and should be considered when performing comprehensive clinical knee examination.For any figures or tables, please contact authors directly.

Preserving primary medial static stabilizer ligaments achieves physiological knee kinematics in total knee arthroplasty

PurposeAs postoperative knee instability has been reported to be one of the critical reasons for early failure in total knee arthroplasty (TKA), obtaining optimal knee stability—especially in medial—was indispensable for successful TKA. We hypothesized that preserving medial soft tissue structures was the key to maintain physiological medial knee stability. Thus, TKAs with preserving primary medial static stabilizer ligaments technique were performed, and the postoperative knee kinematics was evaluated. MethodsPrimary knee osteoarthritis patients with varus knee deformity and planed for primary TKA were enrolled. However, patients with severe varus knee deformities, valgus knee deformities, and rheumatoid arthritis were excluded. TKAs were performed by removing medial femoral and tibial osteophytes; however, the primary medial static stabilizer ligaments—the superficial medial collateral ligament (MCL), deep MCL, and posterior oblique ligament—were not released. The cruciate-retaining (CR), posterior-stabilized (PS), and medial-pivot (MP) inserts were implanted, and the knee kinematics was measured. These data were statistically analyzed using analysis of variance. The institutional review board approved the study. ResultsFrom full extension to maximum flexion, the lateral femoral condyle moved backward, greater than the medial femoral condyle, and consequently the femur external rotated on the tibia. These kinematics patterns were shown in CR, PS, and MP groups. ConclusionAs the knee kinematics of CR and PS are similar to that of MP, which has been reported to demonstrate physiological knee kinematics, preserving primary medial static stabilizer ligaments technique could potentially preserve physiological knee kinematics.

Contribution of the Medial Hamstrings to Valgus Stability of the Knee.

Multiligament knee injuries involving the medial side are common. When performing surgical reconstruction, use of the medial hamstrings (HS) as grafts remains controversial in this setting. To determine the role of the medial HS in stabilizing the valgus knee for different types of medial-sided knee injury. Controlled laboratory study. A biomechanical study on 10 cadaveric knees was performed. Valgus load (force moment of 10 N/m) was applied at 0°, 30°, and 60° of flexion, and the resultant rotation was recorded using an optoelectronic motion analysis system. Measurements were repeated for 4 different knee states: intact knee, superficial medial collateral ligament (sMCL) injury, deep medial collateral ligament (dMCL) injury, and posterior oblique ligament (POL) injury. For each state, 4 loading conditions (+ loaded; - unloaded) of the semitendinosus (ST) and gracilis (GRA) tendons were tested: ST+/GRA+, ST+/GRA-, ST-/GRA+, and ST-/GRA-. At 0° of flexion, combined unloading of the ST and GRA (ST-/GRA-) increased valgus laxity on the intact knee compared with the ST+/GRA+ condition (P < .05). For all medial-sided injury states (isolated sMCL; combined sMCL and dMCL; and combined sMCL, dMCL, and POL damage), ST-/GRA- increased valgus laxity at 0° and 30° of flexion versus ST+/GRA+ (P < .05 for all). The absolute value of valgus laxity increased with the severity of medial-sided ligament injury. Isolated ST unloading increased valgus laxity for the intact knee and the MCL-injured knee (combined sMCL and dMCL) at 0° of flexion (P < .05 vs ST+/GRA+). Isolated unloading of the GRA had no effect on valgus knee stability. The medial HS tendons contributed to the stabilization of the knee in valgus, and this was even more important when the medial side was severely affected (POL damage). This stabilizing effect was greater between 0° and 30°, in which the POL is the main valgus stabilizer. When deciding on graft selection for multiligament knee injury reconstruction, the surgeon should be aware of the effect of harvesting the medial HS tendon on valgus laxity.

A New Algorithm to Treat Chronic Combined ACL/MCL Injuries: Let's Come Back to the “Rotatory Instability Test”

Background: Chronic combined medial collateral ligament (MCL) and anterior cruciate ligament (ACL) injuries are frequent. Medial residual laxity is a risk factor for ACL rerupture. It should be treated at the same time as the ACL reconstruction (ACLR) if necessary, but there are still questions surrounding the indications for abstention or surgery of the medial plan, especially for grade 2 MCL injuries of the Fetto and Marshall classification. Indications: The purpose is to come back to a simple test, the “Rotatory Instability Test” as described by Slocum and Larson in 1968 for systematic clinical examination of the knee to improve the sensitivity and accuracy of the deep MCL (dMCL) and superficial MCL (sMCL) examination and to propose a decision-making algorithm for the treatment of the chronic combined ACL/MCL injuries based on the assessment of anteromedial rotatory instability (AMRI). Technique Description: Examination of the ACL with Lachman test, anterior drawer in neutral rotation, and pivot shift test confirm the ACL injury. Valgus laxity is tested in extension and at 20° of flexion. Then, an anterior drawer test at 90° of flexion with external rotation is done (the anterior drawer in external rotation [ADER] test) allowing to identify isolated dMCL, dMCL + sMCL, or MCL + posterior oblique ligament (POL) injuries. Discussion: As persistent medial laxity is a risk factor for ACL graft failure and there is no reliable method of instrumented laxity assessment, careful clinical examination remains essential. Systematic examination of the medial side with valgus laxity testing at 0° and 20° flexion combined with the ADER test assessment of AMRI can guide treatment of the MCL injury component. Where there is no valgus laxity and the ADER test is negative, isolated ACLR is indicated. If there is significant medial laxity at 0°, this suggests combining sMCL and POL reconstruction with ACLR. Where the knee is stable at 0° but there is valgus laxity at 20° and a positive ADER test, the dMCL can be reconstructed using a gracilis graft or a combined sMCL and dMCL reconstruction can be added to the ACLR depending on the degree of laxity. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

DEEP MEDIAL COLLATERAL LIGAMENT RECONSTRUCTION OF THE KNEE RESTORES ROTATIONAL STABILITY THROUGHOUT FULL RANGE OF MOTION WHILE CONTEMPORARY MCL RECONSTRUCTION ONLY DOES IN EXTENSION

AbstractIntroductionHistoric MCL reconstruction techniques focused on the superficial MCL to restore valgus stability while overlooking tibial external rotation and the deep MCL. This study assessed the ability of a contemporary medial collateral ligament (MCL) reconstruction and a deep MCL (dMCL) reconstruction to restore rotational and valgus knee stability.MethodsSix pairs fresh-frozen cadaveric knee specimens with intact soft tissue were tested in four states: 1) intact 2) after sMCL and dMCL sectioning, 3) contemporary MCL reconstruction (LaPrade et al), and 4) dMCL reconstruction. In each state, four loading conditions were applied at varying flexion angles: 8Nm valgus torque, 5Nm tibial external rotation torque, 90N anterior drawer, and combined 90N anterior drawer plus 5Nm tibial external rotation torque.ResultsTransection of the sMCL and dMCL resulted in increased laxity with valgus torque, external rotation torque, and combined anterior drawer plus external rotation. dMCL reconstruction restored external rotation stability to intact levels throughout all degrees of flexion but did not restore valgus stability at any flexion angle. Contemporary MCL reconstruction restored valgus and external rotation stability at 0° and 20° and valgus stability at 40°. In the combined anterior drawer plus tibial external rotation trial, the dMCL restored stability at 20° and improved stability between 40° and 90° flexion. Conversely, the contemporary MCL reconstruction did not restore stability at any degree of flexion.ConclusionDeep MCL reconstruction restored rotational stability to the knee throughout range of motion but not valgus stability. The contemporary MCL reconstruction restored stability only near full extension.

The Anterior Fibers of the Superficial MCL and the ACL Restrain Anteromedial Rotatory Instability

Background: There is limited knowledge about how the anterior cruciate ligament (ACL) and capsuloligamentous structures on the medial side of the knee act to control anteromedial rotatory knee instability. Purpose: To investigate the contribution of the medial retinaculum, capsular structures (anteromedial capsule, deep medial collateral ligament [MCL], and posterior oblique ligament), and different fiber regions of the superficial MCL to restraining knee laxity, including anteromedial rotatory instability. Study Design: Controlled laboratory study. Methods: Eight fresh-frozen human cadaveric knees were tested using a 6 degrees of freedom robotic testing system in a position-controlled mode. Loads of 10 N·m valgus rotation, 5 N·m tibial external rotation, 5 N·m tibial internal rotation, and 134 N anterior tibial translation in 5 N·m external rotation were applied at different flexion angles. The motion of the intact knee at 0° to 120° of flexion was replicated after sequential excision of the sartorial fascia; anteromedial retinaculum; anteromedial capsule; anterior, middle, and posterior fibers of the superficial MCL; the deep MCL; the posterior oblique ligament; and the ACL. The reduction in force/torque indicated the contribution of each resected structure to resisting laxity. A repeated-measures analysis of variance with a post hoc Bonferroni test was used to analyze the relative force and torque changes from the intact state. Results: The superficial MCL was the most important restraint to valgus rotation from 0° to 120° and provided the largest contribution to resisting external rotation between 30° and 120° of knee flexion, gradually increasing from 25.2% ± 7.4% at 30° to 36.9% ± 15.4% at 90°. The posterior oblique ligament contributed significantly to resisting valgus rotation only in extension (17.2% ± 12.1%) but was the major restraint to internal rotation at 0° (46.7% ± 13.1%) and 30° (30.4% ± 17.7%) of flexion. The sartorial fascia and anteromedial retinaculum resisted ER at all knee flexion angles (P < .05) and was the single most important restraint in the extended knee (19.5% ± 11%). The capsular structures (anteromedial capsule and deep MCL) had a combined contribution of 20% ± 11.5% at 0° and 23.4% ± 10.5% at 120° of knee flexion but were less important from 30° to 90°. The ACL was the primary restraint to anterior tibial translation in external rotation between 0° and 60° of flexion (50.2% ± 16.9% at 30°), but the superficial MCL was more important at 90° to 120° of knee flexion (36.8% ± 16.4% at 90°). The anterior, middle, and posterior regions of the superficial MCL contributed differently to the simulated laxity tests. The anterior fibers were the most important part of the superficial MCL in resisting external rotation and combined anterior tibial translation in external rotation. Conclusion: The superficial MCL not only was the primary restraint to valgus rotation throughout the range of knee flexion but also importantly contributed to resisting anterior tibial translation in external rotation, particularly in deeper flexion in the cadaveric model. The anterior fibers of the superficial MCL are the most important superficial MCL fibers in resisting anterior tibial translation in external rotation. This study suggests that a medial reconstruction that reproduces the function of the posterior MCL fibers and posterior oblique ligament may not best control anteromedial rotatory instability. Clinical Relevance: Based on these data, there is a need for an individualized medial reconstruction to address different types of medial injury patterns and instabilities.

Poster 297: Deep medial collateral ligament reconstruction of the knee restores rotational stability throughout full range of motion while contemporary MCL reconstruction only does in extension

Objectives: The past decade has taught the importance of identifying and treating the concomitant injuries that frequently occur at the time of ACL rupture. Failure to do so can result in increased stresses on the ACL graft and subsequently increased risk of failure. While the focus has largely been on the menisci and the anterolateral soft tissues, recent studies have highlighted high frequency at which injuries to the medial structures occur in previously presumed isolated ACL tears and the increased risk of poor outcomes when they are not addressed. Injuries to the medial ligament complex result in valgus and anteromedial rotatory instability (AMRI). Historic MCL reconstruction techniques have focused on the superficial MCL in an effort to restore valgus stability while frequently ignoring the importance of the deep MCL in controlling tibial external rotation. The recent recognition of the importance of the medial ligament complex has led to multiple studies revisiting medial sided anatomy and questioning contemporary MCL reconstruction techniques. The objective of this study is to assess and compare the ability of a contemporary medial collateral ligament (MCL) reconstruction and a deep MCL (dMCL) reconstruction to restore rotational and valgus stability to the knee. Methods: Six pairs fresh-frozen cadaveric knee specimens were included and with intact soft tissue, the distal femur and tibia were potted in PVC pipes to facilitate biomechanical testing using a customized multi-axial knee activity simulator. Four states were tested: 1) intact 2) after sectioning of the sMCL and dMCL, 3) contemporary MCL reconstruction as described by LaPrade et al, and 4) dMCL reconstruction. In each state, the knees were tested under four loading conditions at varying flexion angles (0°, 20°, 40°, 60° and 90°): 8 Nm valgus torque, 5 Nm tibial external rotation torque, 90N anterior drawer, and combined 90 N anterior drawer plus 5 Nm tibial external rotation torque. Results: Transection of the sMCL and dMCL resulted in increased laxity with the application of the valgus torque, external rotation torque, and combined anterior drawer plus external rotation at all flexion angles. dMCL reconstruction restored external rotation stability to intact levels (all p&lt;0.05) throughout all degrees of flexion (Figure 1), yet dMCL reconstruction did not restore valgus stability at any flexion angle (Figure 2). Contemporary MCL reconstruction restored valgus and external rotation stability at 0° and 20° and valgus stability at 40° (p&lt;0.01). In response to a combined anterior drawer plus tibial external rotation, the dMCL restored stability back to the intact level at 20° and improved stability between 40° and 90° flexion (Figures 3 and 4). In contrast, the contemporary MCL reconstruction did not restore stability at any degree of flexion (p&gt;0.05). Conclusions: Deep MCL reconstruction restored rotational stability to the knee throughout range of motion but did not restore valgus stability. The contemporary MCL reconstruction restore stability only near full extension.

High Prevalence of Superficial and Deep Medial Collateral Ligament Injuries on Magnetic Resonance Imaging in Patients With Anterior Cruciate Ligament Tears

To assess the prevalence of and factors associated with medial collateral ligament (MCL) complex injuries on magnetic resonance imaging (MRI) in patients with anterior cruciate ligament (ACL) tears. Data were extracted from the Natural Corollaries and Recovery After ACL Injury (NACOX) multicenter longitudinal cohort study. Between May 2016 and October 2018, patients who presented to 1 of 7 health care clinics across Sweden with an ACL tear sustained no more than 6 weeks earlier and who were aged between 15 and 40 years at the time of injury were invited to participate. All the patients included in this study underwent MRI. The mean time from injury to MRI was 19.6 ± 15.2 days. An orthopaedic surgeon specializing in knee surgery and a musculoskeletal radiologist reviewed all MRI scans. Injuries to the superficial MCL (sMCL), deep MCL (dMCL), and posterior oblique ligament were identified. Stepwise forward multiple binary logistic regression analyses were used to evaluate patient characteristics (age, sex, body mass index, preinjury Tegner activity level, and activity at injury) and injuries on MRI (lateral meniscus [LM] injury, medial meniscus [MM] injury, pivot shift-type bone bruising, medial femoral condyle [MFC] bone bruising, and lateral femoral condyle [LFC] impaction) associated with the presence of MCL complex tears. In total, 254 patients (48.4% male patients) with a mean age of 25.4 ± 7.1 years were included. The overall prevalence of MCL (sMCL and dMCL) injuries and isolated dMCL injuries was 16.5% (42 of 254) and 24.8% (63 of 254), respectively. No isolated sMCL injuries were found. Posterior oblique ligament injuries were found in 12 patients (4.7%) with MCL (sMCL and dMCL) injuries. An LM injury (odds ratio [OR], 3.94; 95% confidence interval [CI], 1.73-8.94; P= .001) and LFC impaction (OR, 2.37; 95% CI, 1.11-5.07; P= .02) increased the odds of having an MCL injury, whereas an MM injury (OR, 0.26; 95% CI, 0.12-0.59; P= .001) reduced the odds. Isolated dMCL injuries were significantly associated with MFC bone bruising (OR, 4.21; 95% CI, 1.92-9.25; P < .001) and LFC impaction (OR, 3.86; 95% CI, 1.99-7.49; P < .001). The overall combined prevalence of MCL (sMCL and dMCL) injuries and isolated dMCL injuries in patients with ACL tears was high (16.5%+ 24.8%= 41.3%). The presence of an LM injury and LFC impaction increased the odds of having an MCL injury, whereas the presence of an MM injury reduced the odds. MFC bone bruising and LFC impaction were associated with the presence of isolated dMCL injuries. Level III, retrospective cohort study.

Reanalysis of the Posterior Oblique Ligament: Quantitative Anatomy, Radiographic Markers, and Biomechanical Properties.

The posterior oblique ligament (POL) is the largest structure of the posteromedial knee that is at risk of injury in conjunction with the medial collateral ligament (MCL). Its quantitative anatomy, biomechanical strength, and radiographic location have not been assessed in a single investigation. To evaluate the 3-dimensional and radiographic anatomy of the posteromedial knee and the biomechanical strength of the POL. Descriptive laboratory study. Ten nonpaired fresh-frozen cadaveric knees were dissected and medial structures were elevated off bone, leaving the POL. The anatomic locations of the related structures were recorded with a 3-dimensional coordinate measuring machine. Anteroposterior and lateral radiographs were taken with radiopaque pins inserted into the pertinent landmarks, and the distances between the collected structures were calculated. Each knee was then mounted to a dynamic tensile testing machine, and pull-to-failure testing was performed to record the ultimate tensile strength, stiffness, and failure mechanism. The POL femoral attachment was a mean of 15.4 mm (95% CI, 13.9-16.8 mm) posterior and 6.6 mm (95% CI, 4.4-8.8 mm) proximal to the medial epicondyle. The tibial POL attachment center was a mean of 21.4 mm (95% CI, 18.1-24.6 mm) posterior and 2.2 mm (95% CI, 0.8-3.6 mm) distal to the center of the deep MCL tibial attachment and a mean of 28.6 mm (95% CI, 24.4-32.8 mm) posterior and 41.9 mm (95% CI, 36.8-47.0 mm) proximal to the center of the superficial MCL tibial attachment. On lateral radiographs, the femoral POL was a mean of 17.56 mm (95% CI, 14.83-21.95 mm) distal to the adductor tubercle and 17.32 mm (95% CI, 14.6-21.7 mm) posterosuperior to the medial epicondyle. On the tibial side, the center of the POL attachment was a mean of 4.97 mm (95% CI, 3.85-6.79 mm) distal to the joint line on anteroposterior radiographs and 6.34 mm (95% CI, 5.01-8.48 mm) distal to the tibial joint line on lateral radiographs, at the far posterior tibial aspect. The biomechanical pull-to-failure demonstrated a mean ultimate tensile strength of 225.2 ± 71.0 N and a mean stiffness of 32.2 ± 13.1 N. The anatomic and radiographic locations of the POL and its biomechanical properties were successfully recorded. This information is useful to better understand POL anatomy and biomechanical properties as well as to clinically address an injury with repair or reconstruction.

The Deep-MCL Line: A Reliable Anatomical Landmark to Optimize the Tibial Cut in UKA.

The extramedullary guides for the tibial resection during medial unicompartmental knee arthroplasty (UKA) are inaccurate, with an error risk in coronal and sagittal planes and cut thickness. It was our hypothesis that the use of anatomical landmarks for the tibial cut can help the surgeon to improve accuracy. The technique described in this paper is based on the use of a simple and reproducible anatomical landmark. This landmark is the line of insertion of the fibers of the deep medial collateral ligament (MCL) around the anterior half of the medial tibial plateau called the "Deep MCL insertion line". The used anatomical landmark determines the orientation (in the coronal and sagittal planes) and the thickness of the tibial cut. This landmark corresponds to the line of insertion of the fibers of the deep MCL around the anterior half of the medial tibial plateau. A consecutive series of patients who underwent primary medial UKA between 2019 and 2021 were retrospectively reviewed. A total of 50 UKA were included. The mean age at the time of surgery was 54.5 ± 6.6 years (44-79). The radiographic measurements showed very good to excellent intra-observer and inter-observer agreements. The limb and implant alignments and the tibial positioning were satisfying, with a low rate of outliers and good restoration of the native anatomy. The landmark of the insertion of deep MCL constitutes a reliable and reproducible reference for the tibial cut axis and thickness during medial UKA, independent of the wear severity.

Medial-Sided Ligamentous Injuries of the Athlete's Knee: Evaluation and Management.

The superficial medial collateral ligament (sMCL) is the most commonly injured ligamentous structure in the knee. The other medial knee stabilizers include the deep medial collateral ligament, the posterior oblique ligament, and the medial meniscus. Medial collateral ligament injuries frequently occur in young athletes. As a result of the good healing capacity of the sMCL, the majority of acute medial-sided knee injuries can be treated nonoperatively with good outcomes. However, missed concomitant injuries can lead to residual laxity and instability of the knee when treated conservatively. When surgical management is warranted, numerous techniques exist, including repair, augmentation, and reconstruction. Recent anatomic and biomechanical studies defining the attachment sites and functional roles of the individual medial knee structures have led to advancements in diagnosis, treatment, and rehabilitation. These studies have allowed for the development of an anatomic reconstruction technique that restores the native stability and load-sharing relationships among the medial knee structures. The purpose of this narrative review is to summarize the recent updates in the anatomy, biomechanics, evaluation, and treatment of ligamentous injuries on the medial side of the athlete's knee.