The bone attachments of the medial collateral and posterior oblique ligaments are defined anatomically and radiographically

Simulation of osteotomy in total knee arthroplasty with femoral extra-articular deformity assisted by artificial intelligence: a study based on three-dimensional models

BACKGROUND

The impact of extra-articular deformities (EADs) on lower limb alignment and collateral ligament integrity during total knee arthroplasty (TKA) poses significant challenges, increasing surgical complexity. Our study aims to evaluate the influence of EADs on mechanical axis alignment and the risk of collateral ligament injury during TKA using an AI-assisted surgical planning system, with the goal of minimizing ligament damage through precise and scientific planning.

METHODS

A healthy volunteer underwent CT and MRI scans of the lower limbs. The scan images were imported into Mimics 20.0 software, and the reconstructed models were spatially aligned using 3-maticResearch 11.0 software. Using Unigraphics NX9.0 software, 50 three-dimensional models of femoral lateral joint deformities with varying positions and angles were created. Finally, TKA was simulated using the AI JOINT preoperative planning system.

RESULTS

The larger the deformity angle and the closer it is to the knee joint, the more pronounced the deviation of the mechanical axis. During MA-aligned osteotomy, nine types of deformities can damage the collateral ligaments. After adjusting the varus/valgus of the prosthesis within a safe range of 3° and leaving a residual 3° varus/valgus in the lower limb alignment, only the 25° varus and 25° valgus deformities located at 90% of the femoral anatomical axis remain uncorrected.

CONCLUSION

For patients with osteoarthritis and concurrent EAD undergoing TKA, using reconstructed 3D models of the collateral ligaments for preoperative planning helps visually assess collateral ligament damage, providing a practical solution. Minimizing intra-articular osteotomies within a safe range and allowing some residual alignment deviation can reduce the risk of collateral ligament injury.

Trilogy of isolated deep medial collateral ligament injuries of the knee: A set of three cases and overview of the literature

The authors present three unique cases of isolated deep medial collateral ligament (dMCL) injuries and comprehensively review the current literature. An isolated dMCL injury is often overlooked in clinical practice, and a consensus on the most adequate treatment is needed. Three male patients were examined at our institution directly following the trauma. The first patient experienced isolated soft-tissue avulsion of the dMCL, the second patient had a bony avulsion from the femoral insertion of the dMCL, and the third patient presented with an isolated "reverse Segond" fracture, which has not previously been described in the literature. All three injuries resulted from a violent external knee joint rotation. The treatment regime included a knee brace for up to 5 weeks and a physical therapy regimen for up to 3 months. All three patients reported satisfactory outcomes regarding restored knee function, absence of symptoms, and early return to activities at the final follow-up. STUDY DESIGN: Case report. LEVEL OF EVIDENCE: IV.

Medial collateral ligament section during unicompartmental knee arthroplasty managed by direct repair and fascia lata augmentation autograft: a case report and surgical technique

Background

The medial collateral ligament (MCL) is crucial for ensuring implant stability after unicompartmental knee arthroplasty (UKA). Intraoperative MCL lesions can cause valgus instability, affecting function and implant longevity, and thereby negatively impacting the patient's outcome. Every surgeon who performs UKA may encounter this complication in their daily practice. In this context, this case report presents a rescue technique. The existing literature does not specify a protocol for managing this complication. This article presents the first instance of accidental midsubstance section of the MCL during medial UKA, managed through primary suture and augmentation repair with a fascia lata (FL) autograft. The procedure was subsequently replicated step by step on an anatomical specimen.

Case Description

A 54-year-old woman, previously successfully treated with right medial UKA, was referred to our clinic following an unsuccessful attempt at conservative treatment for osteoarthritis in the left knee. Scheduled for a left medial UKA, an inadvertent midsubstance transection of the deep part of the MCL was encountered during the procedure, resulting in valgus instability. The MCL was promptly repaired and reinforced using an ipsilateral FL augmentation autograft. Subsequent UKA surgery was successfully completed. Follow-up at one year revealed favorable post-operative outcomes, with symmetrical stability on stress radiographs and no indications of early loosening.

Conclusions

To our knowledge, this article represents the first documentation of the direct management for this rare yet severe complication. This case report could therefore inspire any surgeon facing this complication. The technique, grounded in biomechanical principles, ensures direct medial stability whilst allowing uninterrupted continuation of the initial procedure. Characterized by simplicity and reproducibility, the approach demonstrates favorable short-term outcomes. Because the results should be interpreted considering the limited impact of a case report, further prospective studies are essential to substantiate and strengthen these findings.

Modeling of the native knee with kinematic data derived from experiments using the VIVO™ joint simulator: a feasibility study

BACKGROUND

Despite advances in total knee arthroplasty, many patients are still unsatisfied with the functional outcome. Multibody simulations enable a more efficient exploration of independent variables compared to experimental studies. However, to what extent numerical models can fully reproduce knee joint kinematics is still unclear. Hence, models must be validated with different test scenarios before being applied to biomechanical questions.

METHODS

In our feasibility study, we analyzed a human knee specimen on a six degree of freedom joint simulator, applying a passive flexion and different laxity tests with sequential states of ligament resection while recording the joint kinematics. Simultaneously, we generated a subject-specific multibody model of the native tibiofemoral joint considering ligaments and contact between articulating cartilage surfaces.

RESULTS

Our experimental data on the sequential states of ligament resection aligned well with the literature. The model-based knee joint kinematics during passive flexion showed good agreement with the experiment, with root-mean-square errors of less than 1.61 mm for translations and 2.1° for knee joint rotations. During laxity tests, the experiment measured up to 8 mm of anteroposterior laxity, while the numerical model allowed less than 3 mm.

CONCLUSION

Although the multibody model showed good agreement to the experimental kinematics during passive flexion, the validation showed that ligament parameters used in this feasibility study are too stiff to replicate experimental laxity tests correctly. Hence, more precise subject-specific ligament parameters have to be identified in the future through model optimization.

[Reconstruction of the medial collateral ligament complex with a flat semitendinosus auto- or allograft]

OBJECTIVE

Replacement of superficial medial collateral ligament (sMCL) and posterior oblique ligament (POL) with an allograft.

INDICATIONS

Chronic 3° isolated medial instability and combined anteromedial or posteromedial instability.

CONTRAINDICATIONS

Infection, open growth plates, restricted range of motion (less than E/F 0-0-90°).

SURGICAL TECHNIQUE

Longitudinal incision from medial epicondyle to superficial pes anserinus and exposure of the medial collateral ligament complex. Thawing of the allogeneic semitendinosus tendon graft at room temperature, reinforcement of the tendon ends with sutures and preparation of a two-stranded graft. Placement of guidewires in the sMCL and POL insertions and control with image intensifier. Tunnel drilling. Pulling the graft loop into the femoral bone tunnel and fixation with a flip button. Pulling the two graft ends into the tibial tunnels. Tibial fixation by knotting the suture ends in a 20° flexion on the lateral cortex. Suture the tendon bundles to the remaining remnants of the medial collateral ligament complex to adopt the flat structure of the natural medial collateral ligament complex.

POSTOPERATIVE MANAGEMENT

Six weeks partial weight-bearing, immediately postoperatively splint in the extended position, after 2 weeks movable knee brace for another 4-6 weeks. Mobility: 4 weeks 0-0-60, 5th and 6th weeks 0-0-90.

RESULTS

From 2015-2021, this surgical procedure was performed in 19 patients (5 women, 14 men, age 34 years). Mean Lysholm score at follow-up after at least 2 years was 89 (76-99) points. In 6 patients, there was restricted range of motion 3 months postoperatively, which resulted in further therapy (3 × systemic cortisone therapy, 3 × arthroscopically supported manipulations under anesthesia).

Ligament augmentation and reconstruction system (LARS) synthetic grafts are safe and effective for medial collateral ligament and posterolateral corner reconstructions in elite athletes

PURPOSE

This study documents the efficacy and safety of using a Ligament Augmentation and Reconstruction System (LARS) ligament graft to augment extra-articular knee ligament reconstructions in elite athletes by reporting return-to-play (RTP) rates and levels, career longevity and complications.

METHODS

A consecutive series of all extra-articular knee ligament reconstructions augmented by LARS ligaments in elite athletes undertaken by three specialist sports knee surgeons between 2013 and 2020 were reviewed. Seventy-six elite athletes, aged over 16 years old, and more than 2 years postsurgery were included. RTP was defined as competing at professional level or national/international level in amateur sport.

RESULTS

There were 64 medial collateral ligament (MCL) and 12 posterolateral corner (PLC) reconstructions. Fifty-two (68.4%) underwent concomitant autograft cruciate ligament(s) reconstruction. The mean age was 25.1 years (SD ± 4.5). Most were football (35, 46.1%) or rugby players (35, 46.1%). Sixty-seven athletes (88.2%) RTP with 65 (97.0%) of these playing at the same or higher Tegner level. Fifty-six (83.6%) of the athletes that RTP were still playing at 2 years postsurgery. Twenty (57.1%) of those who had RTP and were more than 5 years postsurgery were still playing at 5 years. Six (7.9%) players required further surgery relating to the LARS/metalwork. One case had soft tissue inflammation adjacent to the proximal end of the synthetic graft, but it is unknown if this was mechanical irritation or a biological reaction. One MCL reruptured 4 years after RTP.

CONCLUSION

Utilising LARS to augment extra-articular knee ligament reconstructions allows 88.2% of athletes with a variety of knee ligament injuries to return to elite sport. The low morbidity rates coupled with 57% of athletes still playing 5 years postsurgery demonstrates that the LARS is safe and effective in these cases. Although there are reports of LARS ligaments being used in MCL and PLC reconstructions, there is very little evidence investigating if they are safe and effective. This study demonstrates that LARS synthetic grafts can be safely used for MCL and PLC reconstructions in elite athletes and they permit a high RTP with a low risk of complications.

LEVEL OF EVIDENCE

Level IV.

Evolution of the term "epicondyle of the femur": Revisiting the anatomical and surgical literature

The femoral epicondyle is an anatomical bony landmark essential for surgeons and anatomists, but there are discrepancies between the two fields when using this term. In current orthopedic surgery, it commonly denotes the small bony prominence of the femoral condyle. Given the derivation, "epicondyle" should be a region projecting laterally from the articular surface rather than a point. These discrepancies in usage are found not only between the fields but also in the literature. This article reviews the narrative definition of "epicondyle of the femur" in surgery and the evolution of the term in anatomy. The outcomes of the review suggest a relationship between the differing perceptions of the epicondyle and the evolution of the term. In reports of studies related to the epicondyle, it is strongly recommended that the definition of the word is clearly stated, with an understanding of its evolution.

Double-Bundle Medial Collateral Ligament Reconstruction Improves Anteromedial Rotatory Instability

BACKGROUND

New techniques have been proposed to better address anteromedial rotatory instability in a medial collateral ligament (MCL)-injured knee that require an extra graft and more surgical implants, which might not be feasible in every clinical setting.

PURPOSE

To investigate if improved resistance to anteromedial rotatory instability can be achieved by using a single-graft, double-bundle (DB) MCL reconstruction with a proximal fixation more anteriorly on the tibia, in comparison with the gold standard single-bundle (SB) MCL reconstruction.

STUDY DESIGN

Controlled laboratory study.

METHODS

Eight fresh-frozen human cadaveric knees were tested using a 6 degrees of freedom robotic simulator in intact knee, superficial MCL/deep MCL-deficient, and reconstruction states. Three different reconstructions were tested: DB MCL no proximal tibial fixation and DB and SB MCL reconstruction with proximal tibial fixation. Knee kinematics were recorded at 0°, 30°, 60°, and 90° of knee flexion for the following measurements: 8 N·m of valgus rotation (VR), 5 N·m of external tibial rotation, 5 N·m of internal tibial rotation, combined 89 N of anterior tibial translation and 5 N·m of external rotation for anteromedial rotation (AMR) and anteromedial translation (AMT). The differences between each state for every measurement were analyzed with VR and AMR/AMT as primary outcomes.

RESULTS

Cutting the superficial MCL/deep MCL increased VR and AMR/AMT in all knee positions except at 90° for VR (P < .05). All reconstructions restored VR to the intact state except at 90° of knee flexion (P < .05). The DB MCL no proximal tibial fixation reconstruction could not restore intact AMR/AMT kinematics in any knee position (P < .05). Adding an anterior-based proximal tibial fixation restored intact AMR/AMT kinematics at ≥30° of knee flexion except at 90° for AMT (P < .05). The SB MCL reconstruction could not restore intact AMR/AMT kinematics at 0° and 90° of knee flexion (P < .05).

CONCLUSION

In this in vitro cadaveric study, a DB MCL reconstruction with anteriorly placed proximal tibial fixation was able to control AMR and AMT better than the gold standard SB MCL reconstruction.

CLINICAL RELEVANCE

In patients with anteromedial rotatory instability and valgus instability, a DB MCL reconstruction may be superior to the SB MCL reconstruction, without causing extra surgical morbidity or additional costs.

Shedding light on the non-operative treatment of the forgotten side of the knee: rehabilitation of medial collateral ligament injuries-a systematic review

Objective

The purpose of this study was to review the current literature regarding the non-operative treatment of isolated medial collateral ligament (MCL) injuries.

Design

Systematic review, registered in the Open Science Framework (https://doi.org/10.17605/OSF.IO/E9CP4).

Data sources

The Embase, MEDLINE and PEDro databases were searched; last search was performed on December 2023.

Eligibility criteria

Peer-reviewed original reports from studies that included information about individuals who sustained an isolated MCL injury with non-surgical treatment as an intervention, or reports comparing surgical with non-surgical treatment were eligible for inclusion. Included reports were synthesised qualitatively. Risk of bias was assessed with the Risk of Bias Assessment tool for Non-randomized Studies. Certainty of evidence was determined using the Grading of Recommendations Assessment Development and Evaluation.

Results

A total of 26 reports (1912 patients) were included, of which 18 were published before the year 2000 and 8 after. No differences in non-operative treatment were reported between grade I and II injuries, where immediate weight bearing and ambulation were tolerated, and rehabilitation comprised different types of strengthening exercises with poorly reported details. Some reports used immobilisation with a brace as a treatment method, while others did not use any equipment. The use of a brace and duration of use was inconsistently reported.

Conclusion

There is substantial heterogeneity and lack of detail regarding the non-operative treatment of isolated MCL injuries. This should prompt researchers and clinicians to produce high-quality evidence studies on the promising non-operative treatment of isolated MCL injuries to aid in decision-making and guide rehabilitation after MCL injury.

Level of evidence

Level I, systematic review.

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.

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

PURPOSE

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).

METHODS

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).

RESULTS

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.

CONCLUSION

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.

LEVEL OF EVIDENCE

There is no level of evidence as this study was an experimental laboratory study.

ArUco-based stylus reliability for reproductible 3D digitalisation of shoulder cartilage contours

Imaging techniques in anatomy have developed rapidly over the last decades through the emergence of various 3D scanning systems. Depending on the dissection level, non-contact or tactile contact methods can be applied on the targeted structure. The aim of this study was to assess the inter and intra-observer reproducibility of an ArUco-based localisation stylus, that is, a manual technique on a hand-held stylus. Ten fresh-frozen, unembalmed adult arms were used to digitalise the glenoid cartilage related to the glenohumeral joint and the contour of the clavicle cartilage related to the acromioclavicular joint. Three operators performed consecutive digitalisations of each cartilage contour using an ArUco-based localisation stylus recorded by a single monocular camera. The shape of each cartilage was defined by nine shape parameters. Intra-observer repeatability and inter-observer reproducibility were computed using an intra-class correlation (ICC) for each of these parameters. Overall, 35.2 ± 2.4 s and 26.6 ± 10.2 s were required by each examiner to digitalise the contour of a glenoid and acromioclavicular cartilage, respectively. For most parameters, good-to-excellent agreements were observed concerning intra-observer (ICC ranging between 0.81 and 1.00) and inter-observer (ICC ranging between 0.75 and 0.99) reproducibility. To conclude, through a fast and versatile process, the use of an ArUco-based localisation stylus can be a reliable low-cost alternative to conventional imaging methods to digitalise shoulder cartilage contours.

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.

Reconstruction of the Medial Collateral Ligament Complex With a Flat Allograft Semitendinosus Tendon

The aim of this Technical Note is to reconstruct the medial collateral ligament complex with the superior medial collateral ligament and posterior oblique ligament as anatomically as possible. An allograft or contralateral semitendinosus autograft is used for anatomic reconstruction of the superior medial collateral ligament and posterior oblique ligament. After bony fixation, the tendon bundles are sutured to the remnants of the medial collateral ligament complex. Thus, the tubular grafts are pulled apart to form a flat shape that resembles that of the normal medial ligaments.

[Injuries of the medial side of the knee : When and how should they be treated?]

Different medial structures are responsible for restraining valgus rotation, external rotation, and anteromedial rotation. When injured this can result in various degrees of isolated and combined instabilities. In contrast to earlier speculation, the posterior oblique ligament (POL) is no longer considered to be the main stabilizer of anteromedial rotatory instability (AMRI). Acute proximal medial ruptures are typically managed conservatively with very good clinical results. Conversely, acute distal ruptures usually require a surgical intervention. Chronic instabilities mostly occur in combination with instabilities of the anterior cruciate ligament (ACL). The clinical examination is a particularly important component in these cases to determine the indications for surgery for an additional medial reconstruction. In cases of severe medial and anteromedial instabilities, surgical treatment should be considered. Biomechanically, a combined medial and anteromedial reconstruction appears to be superior to other reconstruction methods; however, there is currently a lack of clinical studies to confirm this biomechanical advantage.

Evaluation of meniscus extrusion during stair ambulation in healthy volunteers using dynamic ultrasonography: a feasibility study

PURPOSE

This study aimed to investigate the feasibility of evaluating medial meniscus extrusion (MME) during stair ambulation.

METHODS

Twenty healthy young participants (mean age, 22.4 ± 0.9 years) were recruited for this cross-sectional study. Synchronization between the three-dimensional motion system and ultrasonography was used to quantify the extent of meniscal extrusion and knee angles during different tasks, including gait, stair ascent, and stair descent. In particular, ultrasonography was used to record the movements of both the middle and posterior segments of the meniscus to obtain detailed information about these movements in relation to the knee angle. The difference between the maximum MME and the MME at the initial contact (ΔMME) was evaluated during each task in the stance phase.

RESULTS

Visualization of the meniscus in the middle segment was limited with increasing knee flexion angle, whereas the posterior segments were visible during all tasks. ΔMME of the posterior segment during stair ascent and descent was higher than that during gait (gait: 0.68 ± 0.20 mm, ascent: 1.00 ± 0.39 mm, descent: 0.90 ± 0.27 mm, gait-ascent: p = 0.009, gait-descent: p = 0.004).

CONCLUSIONS

Evaluation that includes the posterior segment enables visualization of the medial meniscus and detection of its specific behavior during stair ambulation. These findings demonstrate the feasibility of evaluating meniscus dynamics during stair ambulation, and could contribute to a better understanding of these dynamics.

Development of Multibundle Virtual Ligaments to Simulate Knee Mechanics After Total Knee Arthroplasty

Preclinical evaluation of total knee arthroplasty (TKA) components is essential to understanding their mechanical behavior and developing strategies for improving joint stability. While preclinical testing of TKA components has been useful in quantifying their effectiveness, such testing can be criticized for lacking clinical relevance, as the important contributions of surrounding soft tissues are either neglected or greatly simplified. The purpose of our study was to develop and determine if subject-specific virtual ligaments reproduce a similar behavior as native ligaments surrounding TKA joints. Six TKA knees were mounted to a motion simulator. Each was subjected to tests of anterior-posterior (AP), internal-external (IE), and varus-valgus (VV) laxity. The forces transmitted through major ligaments were measured using a sequential resection technique. By tuning the measured ligament forces and elongations to a generic nonlinear elastic ligament model, virtual ligaments were designed and used to simulate the soft tissue envelope around isolated TKA components. The average root-mean-square error (RMSE) between the laxity results of TKA joints with native versus virtual ligaments was 3.5 ± 1.8 mm during AP translation, 7.5 ± 4.2 deg during IE rotations, and 2.0 ± 1.2 deg during VV rotations. Interclass correlation coefficients (ICCs) indicated a good level of reliability for AP and IE laxity (0.85 and 0.84). To conclude, the advancement of virtual ligament envelopes as a more realistic representation of soft tissue constraint around TKA joints is a valuable approach for obtaining clinically relevant kinematics when testing TKA components on joint motion simulators.

Medial stability and lateral flexibility of the collateral ligaments during mid-range flexion in medial-pivot total knee arthroplasty patients demonstrates favorable postoperative outcomes

PURPOSE

The objectives of the present study were to investigate the length change in different bundles of the superficial medial collateral ligament (sMCL) and lateral collateral ligament (LCL) during lunge, and to evaluate their association with Knee Society Score (KSS) following medial-pivot total knee arthroplasty (MP-TKA).

METHODS

Patients with unilateral MP-TKA knees performed a bilateral single-leg lunge under dual fluoroscopy surveillance to determine the in-vivo six degrees-of-freedom knee kinematics. The contralateral non-operated knees were used as the control group. The attachment sites of the sMCL and LCL were marked to calculate the 3D wrapping length. The sMCL and LCL were divided into anterior, intermediate, and posterior portions (aMCL, iMCL, pMCL, aLCL, iLCL, pLCL). Correlations between lengths/elongation rate of ligament bundles from full extension to 100° flexion and the KSS were examined.

RESULTS

The sMCL and LCL demonstrated relative stability in length at low flexion, but sMCL length decreased whereas LCL increased with further flexion on operated knees. The sMCL length increased at low flexion and remained stable with further flexion, while the LCL length decreased with flexion on the contralateral non-operated knees. The lengths of aMCL, iMCL, and pMCL showed moderate (0.5 < r < 0.7, p < 0.05) negative correlations with the KSS, and the lengths of aLCL, iLCL, and pLCL were positively correlated with the KSS at mid flexion on operated knees (p < 0.05). The elongation rates of aLCL, iLCL, and pLCL were negatively correlated with the KSS at high flexion on operated knees (p < 0.05). However, no significant correlations between the length of different bundles of sMCL or LCL with KSS were found on contralateral non-operated knees.

CONCLUSIONS

The elongation pattern of sMCL/LCL on MP-TKA knees showed differences with contralateral non-operated knees. The sMCL is tense at low to middle flexion and relaxed at high flexion, while LCL is relaxed at low to middle flexion and tense at high flexion following MP-TKA. Medial stability and proper lateral flexibility during mid flexion were associated with favorable postoperative outcomes in MP-TKA patients. In contrast, lateral relaxation at deep flexion should be avoided when applying soft-tissue balancing in MP-TKA.

LEVEL OF EVIDENCE

Level III.

Association of medial collateral ligament complex injuries with anterior cruciate ligament ruptures based on posterolateral tibial plateau injuries

BACKGROUND

The combined injury of the medial collateral ligament complex and the anterior cruciate ligament (ACL) is the most common two ligament injury of the knee. Additional injuries to the medial capsuloligamentous structures are associated with rotational instability and a high failure rate of ACL reconstruction. The study aimed to analyze the specific pattern of medial injuries and their associated risk factors, with the goal of enabling early diagnosis and initiating appropriate therapeutic interventions, if necessary.

RESULTS

Between January 2017 and December 2018, 151 patients with acute ACL ruptures with a mean age of 32 ± 12 years were included in this study. The MRIs performed during the acute phase were analyzed by four independent investigators-two radiologists and two orthopedic surgeons. The trauma impact on the posterolateral tibial plateau and associated injuries to the medial complex (POL, dMCL, and sMCL) were examined and revealed an injury to the medial collateral ligament complex in 34.4% of the patients. The dMCL was the most frequently injured structure (92.2%). A dMCL injury was significantly associated with an increase in trauma severity at the posterolateral tibial plateau (p < 0.02) and additional injuries to the sMCL (OR 4.702, 95% CL 1.3-133.3, p = 0.03) and POL (OR 20.818, 95% CL 5.9-84.4, p < 0.0001). Isolated injuries to the sMCL were not observed. Significant risk factors for acquiring an sMCL injury were age (p < 0.01) and injury to the lateral meniscus (p < 0.01).

CONCLUSION

In about one-third of acute ACL ruptures the medial collateral ligament complex is also injured. This might be associated with an increased knee laxity as well as anteromedial rotational instability. Also, this might be associated with an increased risk for failure of revision ACL reconstruction. In addition, we show risk factors and predictors that point to an injury of medial structures and facilitate their diagnosis. This should help physicians and surgeons to precisely diagnose and to assess its scope in order to initiate proper therapies. With this in mind, we would like to draw attention to a frequently occurring combination injury, the so-called "unlucky triad" (ACL, MCL, and lateral meniscus). Level of evidence Level III Retrospective cohort study.

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

Background

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.

Purpose

To evaluate the 3-dimensional and radiographic anatomy of the posteromedial knee and the biomechanical strength of the POL.

Study Design

Descriptive laboratory study.

Methods

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.

Results

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.

Conclusion

The anatomic and radiographic locations of the POL and its biomechanical properties were successfully recorded.

Clinical Relevance

This information is useful to better understand POL anatomy and biomechanical properties as well as to clinically address an injury with repair or reconstruction.

Safe femoral tunnel drilling angles avoid injury to the medial and posteromedial femoral anatomic structures during single-bundle posterior cruciate ligament reconstruction with the inside-out technique

PURPOSE

To investigate the relationship between the medial and posteromedial femoral anatomic structures and the femoral tunnel exit produced by different tunnel orientations when creating the femoral tunnel for posterior cruciate ligament reconstruction (PCLR) using the inside-out (IO) technique and to estimate safe tunnel orientations to minimize the risk of iatrogenic injury to these structures.

METHODS

Eleven cadaveric knees were used. The medial and posteromedial aspects of each knee joint were dissected to reveal the "safe zone," which is a bony area that avoids the distribution or attachment of at-risk structures (MCL, PMC structures, and articular cartilage), while remaining 10 mm away from the articular cartilage. The hypothesis of this study was that by creating the femoral tunnel at specific angles using the IO technique, the tunnel outlet would be as close to the safe zone as possible, protecting the at-risk structures from damage. Femoral tunnels were drilled at 20 different angle combinations on each specimen: 0°, 15°, 30°, 45°, and 60° relative to a line parallel to the transepicondylar axis in the axial plane, as well as 15°, 30°, 45°, and 60° relative to a line parallel to the femoral axis in the coronal plane. The positional relationship between each tunnel exit and the safe zone was recorded, and the shortest distance between the exit center and the safe zone boundary was measured.

RESULTS

The risk of iatrogenic injury differed depending on the drilling orientation (χ² = 168.880, P < 0.001). Femoral drilling angle combinations of 45/45°, 45/60°, 60/30°, 60/45°, and 60/60° (axial/coronal) were considered relatively safer than other orientations (P < 0.05). The shortest distance between the tunnel exit and the safe zone boundary was negatively correlated with the angle in the axial plane (P < 0.001, r = - 0.810).

CONCLUSIONS

When creating the IO femoral tunnel for single-bundle PCL reconstruction, angle combinations of 45/45°, 45/60°, 60/30°, 60/45°, and 60/60° (axial/oblique coronal) could be utilized to prevent at-risk structures from being damaged. The drilling angles and the safe zone can be employed to optimize the femoral tunnel in PCLR.

[Diagnosis and treatment progress in the femoral insertion injury of medial collateral ligament of knee]

Objective

To summarize the diagnosis and treatment progress in the femoral insertion injury of the medial collateral ligament (MCL) of knee, and to provide a clinical reference for diagnosis and treatment.

Methods

The literature on the femoral insertion injury of the MCL of knee was widely reviewed. The incidence, mechanisms of injury and anatomy, the diagnosis and classification, and status of treatment were summarized.

Results

The mechanism of the femoral insertion injury of the MCL of knee is related to its anatomical and histological characteristics, as well as the abnormal valgus of the knee joint, excessive external rotation of the tibial platform and it is classified according to the injury characteristics to guide the refined and individualized clinical treatment.

Conclusion

Due to different understanding of femoral insertion injury of MCL of knee, the treatment methods are different, and thus is the healing effect. Additional studies are still needed to promote the healing of insertion injuries.

A "Short Isometric Construct" Reconstruction Technique for the Medial Collateral Ligament of the Knee

Recently there has been increased focus on the medial collateral ligament (MCL) and the role the medial ligament complex plays in preventing valgus and external rotation, especially in the setting of a combined ligament injury. Multiple surgical techniques purport to reproduce "normal anatomy"; however, only one technique addresses the deep MCL fibers and the prevention of external rotation. Thus we describe the "short isometric construct" MCL reconstruction which is stiffer than the anatomic reconstructions. The "short isometric construct" technique resists valgus throughout range of motion whereas its obliquity resists tibial external rotation, helping to reduce the risk of anterior cruciate ligament graft re-rupture.

Imaging of the medial collateral ligament of the knee: a systematic review

INTRODUCTION

The primary aim of this investigation was to systematically review relevant literature of various imaging modalities (magnetic resonance imaging (MRI), stress radiography and ultrasonography) in the assessment of patients with a medial collateral ligament (MCL) injury.

MATERIALS AND METHODS

A systematic literature review of articles indexed in PubMed and Cochrane library was performed. Original research reporting data associated with medial gapping, surgical, and clinical findings associated with MCL injuries were considered for inclusion. The methodological quality of each inclusion was also assessed using a verified tool.

RESULTS

Twenty-three imaging studies (magnetic resonance imaging (MRI) n = 14; ultrasonography n = 6; radiography n = 3) were ultimately included into the review. A total of 808 injured, and 294 control, knees were assessed. Interobserver reliabilities were reported in radiographic and ultrasonographic investigations with almost perfect agreement. MRI studies demonstrated agreement ranging between substantial to almost perfect. Intraobserver reliability was only reported in radiographic studies pertinent to medial gapping and was found to be almost perfect. Correlation of MRI with clinical findings was moderate to strong (65-92%). Additionally, MRI imaging was more sensitive in the detection of MCL lesions when compared to clinical examination. However, when compared to surgical findings, MRI underestimated the grade of instability in up to 21% of cases. Furthermore, MRI showed relatively inferior performance in the identification of the exact MCL-lesion location when compared to surgical findings. Interestingly, preoperative clinical examination was slightly inferior to stress radiography in the detection of MCL lesions. However, clinical testing under general anaesthesia performed similar to stress radiography. The methodological quality analysis showed a low risk of bias regarding patient selection and index testing in each imaging modality.

CONCLUSION

MRI can reliably diagnose an MCL lesion but demonstrates limitations in its ability to predict the specific lesion location or grade of MCL instability. Ultrasonography is a widely available, radiation free modality, but is rarely used in clinical practice for detecting MCL lesions and clinical or surgical correlates are scarce. Stress radiography findings correlate with surgical findings but clinical correlations are missing in the literature.

LEVEL OF EVIDENCE

IV.

[Correlation analysis of femoral tunnel angle and medial collateral ligament injury in posterior cruciate ligament single-bundle reconstruction]

Objective

To investigate whether the outlet of the femoral tunnel will cause iatrogenic injury to the medial collateral ligament (MCL) during posterior cruciate ligament reconstruction (PCLR) and estimate the safe angle of femoral tunnel placement.

Methods

Thirteen formaldehyde-soaked human knee joint specimens were used, 8 from men and 5 from women; the donors' age ranged from 49 to 71 years, with an average of 61 years. First, the medial part of the femur was carefully dissected to clearly expose the region of the MCL course and attachment on the femoral medial aspect and to outline the anterior margin of the region with a marked line. The marked line divided the medial femoral condyle into an area with an MCL course and a bare bone area which is regarded relatively safe for no MCL course. Then, the posterior cruciate ligament (PCL) was cut to identify the femoral attachment of the PCL. After the knee joint was fixed at a 120° flexion angle, the process of femoral tunnel preparation for the PCL single-bundle reconstruction was simulated. The inside-out technique was used to drill the femoral tunnel from the PCL femoral footprint inside the knee joint with an orientation to exit the medial condyle of the femur, and the combination angle of the two planes, the axial plane and the coronal plane, was adapted to the process of drilling femoral tunnels at different orientations. The following 15 angle combinations were used in the study: 0°/30°, 0°/45°, 0°/60°, 15°/30°, 15°/45°, 15°/60°, 30°/30°, 30°/45°, 30°/60°, 45°/30°, 45°/45°, 45°/60°, 60°/30°, 60°/45°, 60°/60° (axial/coronal). The positional relationship between the femoral tunnel outlet on the femoral medial condyle and the marked line was used to verify whether the tunnel drilling angle was a risk factor for MCL injury or not, and whether the shortest distance between the femoral exit center and the marked line was affected by the various angle combinations. Furthermore, the safe orientation of the femoral tunnel placement would estimated.

Results

When creating the femoral tunnel for PCLR, there was a risk of damage to the MCL caused by the tunnel outlet, and the incidence was from 0 to 100%; when the drilling angle of the axial plane was 0° and 15°, the incidence of MCL damage was from 69.23% to 100%. There was a significant difference in the incidence of MCL damage among femoral tunnels of 15 angle combinations ( χ ²=148.195, P<0.001). By comparison between groups, it was found that when drilling femoral tunnels at 5 combinations of 45°/45°, 45°/60°, 60°/30°, 60°/45°, and 60°/60° (axial/coronal), the shortest distances between the tunnel exit and the marked line were significantly different than 0°/45°, 0°/60°, 15°/45°, 15°/60°, and 30°/30° (axial/coronal) ( P<0.05). Additionally, after comparing the median of the shortest distance with other groups, the outlets generated by these 5 angles were farther from the marked line and the posterior MCL.

Conclusion

The creation of the femoral tunnel in PCLR can cause iatrogenic MCL injury, and the risk is affected by the tunnel angle. To reduce the risk of iatrogenic injury, angle combinations of 45°/45°, 45°/60°, 60°/30°, 60°/45°, and 60°/60° (axial/coronal) are recommended for preparing the femoral tunnel in PCLR.

High return to play rate following treatment of multiple-ligament knee injuries in 136 elite athletes

PURPOSE

The purpose of the study is to assess return to play rate and timing of elite athletes treated for multi-ligament knee injuries with modern surgical techniques.

METHODS

A retrospective review was performed of all professional or national/international level athletes treated for a multi-ligament knee injury by the senior author in the period from February 2001 to October 2019, with a minimum of 2-year follow-up. The study cohort consisted of 136 elite athletes who underwent surgery of two or more knee ligaments. Outcomes measures were return to play (RTP), defined as return to elite level sport, return to play time, and further surgical procedures.

RESULTS

One hundred and twenty (88.2%) athletes returned to elite level sport at an average of 12.8 months from operation. In unicruciate injuries, ACL and PCL-based injuries had similar return to play rates (89.1% vs. 87.5% respectfully, n.s.) although mean RTP time was longer in those with PCL-based injuries (15.2 vs. 11.9 months, p < 0.01). Bicruciate injuries had longer RTP times compared to unicruciate injuries (mean RTP 16.0vs. 12.4 months, p < 0.05) but were able to return at a similar rate (83.3% vs. 88.9%, n.s.). Medial and lateral sided injuries had similar RTP rates (89.3% vs. 87.9%, n.s.) though lateral sided injuries took longer before returning to play (13.4 vs. 11.6 months, p < 0.05). Further surgery was required in 54 (39.9%) patients including 25 (18.4%) manipulations under anaesthesia. Four (2.9%) of the athletes underwent revision ligament surgery.

CONCLUSION

Modern surgical techniques used in the treatment of multi-ligament knee injuries can lead to high return to play rates in elite athletes.

LEVEL OF EVIDENCE

IV.

Instabilität des Kniegelenks – medial oder anteromedial?

Hintergrund

Verletzungen des medialen Bandkomplexes gehören zu den häufigsten Knieverletzungen. Sie heilen zwar meist mit konservativer Therapie problemlos aus, persistierende Instabilitäten erhöhen aber die Belastung der Kreuzbänder und benötigen speziell bei deren Beteiligung eine adäquate Therapie.

Anatomie und Biomechanik

Der mediale Seitenbandkomplex besteht im Wesentlichen aus dem oberflächlichen Seitenband (sMCL), welches der primäre Stabilisator gegen Valgus ist, dem tiefen Seitenband (dMCL) mit dessen schräg verlaufendem ventralem Anteil (AML), die nur sekundäre Stabilisatoren gegen Valgus darstellen, aber primär gegen Außenrotation stabilisieren, und dem hinteren Schrägband (POL), das in vollständiger Streckung gegen Valgus sowie gegen Innenrotation stabilisiert.

Therapie

Chronische Instabilitäten bzw. höhergradige Verletzungen mit Dislokation der Bandstümpfe oder multiligamentäre Verletzungen bedürfen einer operativen Versorgung. Im Akutstadium zeigen Avulsionsverletzungen bei anatomischer Refixation gutes Heilungspotenzial, während bei intraligamentären Verletzungen zusätzlich zur Naht der Bandanteile eine Augmentation mit Sehnenmaterial empfohlen wird. Bei chronischen Instabilitäten ist die Differenzierung des Instabilitätsmusters ausschlaggebend für die Wahl der Rekonstruktionstechnik (reine sMCL-Rekonstruktion oder kombinierte Rekonstruktion von sMCL und AML). In beiden Fällen kommt die hier beschriebene Technik mit flachem Transplantat der Anatomie näher als bei konventionellen Verfahren.

Diskussion

Rekonstruktionstechniken unter Verwendung flacher Sehnentransplantate, die alle betroffenen Bandanteile adressieren, haben sich biomechanisch als sehr effektiv erwiesen, komplexe mediale Instabilitäten suffizient zu behandeln. Ob diese auch klinisch überlegen sind, werden zukünftige klinische Studien zeigen müssen.

The Mirror Anterolateral Ligament: A Simple Technique to Reconstruct the Deep Medial Collateral Ligament Using the Gracilis Associated With a Four-Strand Semitendinosus for Anterior Cruciate Ligament Reconstruction

We present a surgical technique to reconstruct the deep portion of the medial collateral ligament (MCL) when associated with an injury of the anterior cruciate ligament (ACL). Patients could benefit from this procedure in cases of ACL reconstruction and persistent laxity at 20° of flexion of the MCL without any laxity in extension. This surgery uses the gracilis to reconstruct the deep portion of the MCL in the same manner described for the anterolateral ligament on the other side of the knee. The procedure is performed percutaneously, graft and tunnels are independent from the ACL, a screw is used on the femoral side, and a cortical device is used on the tibial side.

Medial Collateral Ligament Reconstruction: A Gracilis Tenodesis for Anteromedial Knee Instability

The main principle of the present medial collateral ligament reconstruction technique is to address anteromedial knee instability. Therefore, we describe a gracilis tenodesis with 2 functional bundles to reconstruct the deep and superficial medial collateral ligament. The proposed technique may be performed as an isolated or combined procedure with anterior cruciate ligament reconstruction. Valgus instability in extension is a contraindication.

The Control of Anteromedial Rotatory Instability Is Improved With Combined Flat sMCL and Anteromedial Reconstruction

BACKGROUND

Both the superficial medial collateral ligament (sMCL) and the deep MCL (dMCL) contribute to the restraint of anteromedial (AM) rotatory instability (AMRI). Previous studies have not investigated how MCL reconstructions control AMRI.

PURPOSE/HYPOTHESIS

The purpose was to establish the optimal medial reconstruction for restoring normal knee kinematics in an sMCL- and dMCL-deficient knee. It was hypothesized that AMRI would be better controlled with the addition of an anatomically shaped (flat) sMCL reconstruction and with the addition of an AM reconstruction replicating the function of the dMCL.

STUDY DESIGN

Controlled laboratory study.

METHODS

A 6 degrees of freedom robotic system equipped with a force-torque sensor was used to test 8 unpaired knees in the intact, sMCL/dMCL sectioned, and reconstructed states. Four different reconstructions were assessed. The sMCL was reconstructed with either a single-bundle (SB) or a flattened hamstring graft aimed at better replicating the appearance of the native ligament. These reconstructions were tested with and without an additional AM reconstruction. Simulated laxity tests were performed at 0°, 30°, 60°, and 90° of flexion: 10 N·m valgus rotation, 5 N·m internal and external rotation (ER), and an AM drawer test (combined 134-N anterior tibial drawer in 5 N·m ER). The primary outcome measures of this force-controlled setup were anterior tibial translation (ATT; in mm) and axial tibial rotation (in degrees).

RESULTS

Sectioning the sMCL/dMCL increased valgus rotation, ER, and ATT with the simulated AM draw test at all flexion angles. SB sMCL reconstruction was unable to restore ATT, valgus rotation, and ER at 30°, 60°, and 90° of flexion to the intact state (P < .05). Flat MCL reconstruction restored valgus rotation at all flexion angles to the intact state (P > .05). ER was restored at all angles except at 90°, but ATT laxity in response to the AM drawer persisted. Addition of an AM reconstruction improved control of ATT relative to the intact state at all flexion angles (P > .05). Combined flat MCL and AM reconstruction restored knee kinematics closest to the intact state.

CONCLUSION

In a cadaveric model, AMRI resulting from an injured sMCL and dMCL complex could not be restored by an isolated SB sMCL reconstruction. A flat MCL reconstruction or an additional AM procedure, however, better restored medial knee stability.

CLINICAL RELEVANCE

In patients evaluated with a combined valgus and AM rotatory instability, a flat sMCL and an additional AM reconstruction may be superior to an isolated SB sMCL reconstruction.

The "Figure of Four" Reconstruction of the Medial Collateral Ligaments in the Setting of Anteromedial Rotatory Knee Instability Using a Single Autograft

The deep medial collateral ligament plays an important role in controlling tibial external rotation and restrain anterior translation of the medial tibial plateau. Despite being the basic lesion of anteromedial knee instability as proposed by many authors, the majority of the medial side reconstructions do not restore the anatomy and the function of the deep medial collateral ligament. In this Technical Note, we describe a technique to reconstruct both the superficial and deep medial collateral ligament in the setting of anteromedial knee instability using a single peroneus longus autograft.

Proximal tibial morphology is associated with risk of trauma to the posteromedial structures during tibial bone resection reproducing the anatomical posterior tibial slope in bicruciate-retaining total knee arthroplasty

BACKGROUND

A tibial cut with the native posterior tibial slope (PTS) is a theoretical prerequisite in bicruciate-retaining total knee arthroplasty (BCRTKA) to regain physiological knee kinematics. The present study reveals tibial morphological risk factors of trauma to the posteromedial structures of the knee during tibial bone resection in BCRTKA.

METHODS

Fifty patients undergoing BCRTKA for varus knee osteoarthritis were analyzed. A three-dimensional tibial bone model was reconstructed using a computed tomography-based preoperative planning system, and the coronal tibial slope (CTS) and medial PTS (MPTS) were measured. Then, we set the simulated tibial cutting plane neutral on the coronal plane, posteriorly inclined in accordance with the MPTS on the sagittal plane, and 9 mm below the surface of the subchondral cortical bone (i.e., 11 mm below the surface of the cartilage) of the lateral tibial plateau. The association between the tibial morphology and the distance from the simulated cutting plane to the semimembranosus (SM) insertion (Dsm) was analyzed.

RESULTS

Of the 50 patients, 19 (38%) had negative Dsm values, indicating a cut into the SM (namely, below the posterior oblique ligament) insertion. The MPTS was negatively correlated with Dsm (r = -0.396, p = 0.004), whereas the CTS was positively correlated with Dsm (r = 0.619, p < 0.001). On multivariate linear regression analysis, the MPTS and CTS were independent predictors of Dsm.

CONCLUSION

In the setting of tibial cuts reproducing the native MPTS in BCRTKA, patients with larger PTS and smaller CTS had more risk of trauma to the posteromedial structures.

Minimally Invasive Reconstruction of the Medial Collateral Ligament of the Knee

BACKGROUND

This study describes a minimally invasive technique for the reconstruction of the medial collateral ligament (MCL) and posterior oblique ligament (POL) through minimal incisions on the tibial and femoral sides of the ligament using the modified Bosworth technique.

METHODS

This study included 19 consecutive patients who presented with chronic grade III injury; the mean age was 29.6 years (standard deviation ± 7.5 years, range 19-43 years), and five patients (26.3%) had no associated injuries. Ten patients (52.6%) had associated anterior cruciate ligament (ACL) injury and four patients (21.1%) had associated posterior cruciate ligament (PCL) injury. All patients were assessed 18 months postoperatively regarding functional outcome using the Lysholm score and medial joint space opening.

RESULTS

There was a statistically significant improvement in the patient functional outcome as the Lysholm score improved from 55.39 ± 6.9 to 89.42 ± 6.4 at 18 months postoperatively. (P< 0.001). At the end of the follow-up, 16 cases had grade 1 medial laxity, 3 cases with grade II laxity, and no patients with grade III medial laxity.

CONCLUSION

Minimally invasive MCL reconstruction with modified Bosworth technique gives very good results regarding the functional outcome and residual medial laxity of the knee.

Surgical Repair of Stener-like Injuries of the Medial Collateral Ligament of the Knee in Professional Athletes

BACKGROUND

A "Stener-like" lesion of the knee is defined as a distal avulsion of the superficial medial collateral ligament (sMCL) with interposition of the pes anserinus between the ligament and its tibial insertion-a displacement impeding anatomic healing. Because of the scarcity of these injuries, the literature is limited to case reports and small case series.

PURPOSE

To assess the effect of surgical repair of acute Stener-like lesions of the sMCL on the following outcomes: return to preinjury level of sporting function; time to return to preinjury level of sporting function; functional performance; injury recurrence; and any other complications.

STUDY DESIGN

Case series: Level of evidence, 4.

METHODS

This prospective single-surgeon study included 23 elite athletes with a mean age of 27.2 years (range, 19-37 years). Of the participants, 20 were men (87%) and 3 were women (13%). The mean body mass index was 23.1 ± 2.3. A total of 16 athletes were soccer players (70%) and 7 were rugby players (30%), with isolated acute, traumatic Stener-like lesions of the sMCL of the knee confirmed on preoperative magnetic resonance imaging. Surgical repair was undertaken with primary suture anchor repair with ligament repair or reconstruction system (LARS) augmentation. Predefined outcomes were recorded at regular intervals after surgery. The minimum follow-up time was 24 months (range, 24-108 months) from the date of surgery.

RESULTS

The mean time from injury to surgical intervention was 9 days (range, 3-28 days). Overall, 15 (65%) athletes had isolated distal sMCL injuries requiring anatomic suture anchor repair at the distal tibial insertion site only, and 8 (35%) athletes had concomitant injuries of the proximal and distal sMCL and required anatomic suture anchor repair at the proximal and distal attachment sites. Ten athletes required LARS augmentation at the time of the index operation. All study patients returned to their preinjury level of sporting activity in professional soccer or rugby. The mean time from surgical intervention to return to full sporting activity was 16.8 ± 2.7 weeks. At 6 and 24 months' follow-up, all patients had Tegner scores of 10. At a 2-year follow-up, all study patients were still participating at their preinjury level of sporting activity. Three patients developed complications around the LARS that required further surgery to remove synthetic material; however, this did not affect function.

CONCLUSION

Surgical repair of acute Stener-like lesions of the sMCL is associated with a high return to preinjury level of sporting function, excellent functional performance, and a low risk of recurrence at short-term follow-up in elite athletes.

Medial Collateral Ligament Reconstruction for Anteromedial Instability of the Knee: A Biomechanical Study In Vitro

BACKGROUND

Although a medial collateral ligament (MCL) injury is associated with anteromedial rotatory instability (AMRI) and often with an anterior cruciate ligament (ACL) injury, there has been little work to develop anteromedial (AM) reconstruction to address this laxity.

PURPOSE

To measure the ability of a novel "anatomic" AM reconstruction technique to restore native knee laxity for isolated AM insufficiency and combined AM plus posteromedial insufficiency.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 12 cadaveric knees were mounted in a kinematic testing rig that allowed the tibia to be loaded while the knee flexed-extended 0° to 100° with 88-N anteroposterior translation, 5-N·m internal rotation-external rotation (ER), 8-N·m valgus, and combined anterior translation plus ER to simulate AMRI. Joint motion was measured using optical trackers with the knee intact, after superficial MCL (sMCL) and deep MCL (dMCL) transection, and after AM reconstruction of the sMCL and dMCL with semitendinosus autografts. The posteromedial capsule (PMC)/posterior oblique ligament (POL) was then transected to induce a grade 3 medial injury, and kinematic measurements were repeated afterward and again after removing the grafts. Laxity changes were examined using repeated-measures analysis of variance and post-testing.

RESULTS

sMCL and dMCL deficiency increased valgus, ER, and AMRI laxities. These laxities did not differ from native values after AM reconstruction. Additional PMC/POL deficiency did not increase these laxities significantly but did increase internal rotation laxity near knee extension; this was not controlled by AM reconstruction.

CONCLUSION

AM reconstruction eliminated AMRI after transection of the dMCL and sMCL, and also eliminated AMRI after additional PMC/POL transection.

CLINICAL RELEVANCE

Many MCL injuries occur in combination with ACL injuries, causing AMRI. These injuries may rupture the AM capsule and dMCL. Unaddressed MCL deficiency leads to an increased ACL reconstruction failure rate. A dMCL construct oriented anterodistally across the medial joint line, along with an sMCL graft, can restore native knee ER laxity. PMC/POL lesions did not contribute to AMRI.

A Triple-Strand Anatomic Medial Collateral Ligament Reconstruction Restores Knee Stability More Completely Than a Double-Strand Reconstruction: A Biomechanical Study In Vitro

BACKGROUND

There are many descriptions of medial collateral ligament (MCL) reconstruction, but they may not reproduce the anatomic structures and there is little evidence of their biomechanical performance.

PURPOSE

To investigate the ability of "anatomic" MCL reconstruction to restore native stability after grade III MCL plus posteromedial capsule/posterior oblique ligament injuries in vitro.

STUDY DESIGN

Controlled laboratory study.

METHODS

Twelve cadaveric knees were mounted in a kinematic testing rig to impose tibial displacing loads while the knee was flexed-extended: 88-N anteroposterior translation, 5-N·m internal-external rotation, 8-N·m valgus-varus, and combined anterior translation plus external rotation (anteromedial rotatory instability). Joint motion was measured via optical trackers with the knee intact; after superficial MCL (sMCL), deep MCL (dMCL), and posterior oblique ligament transection; and then after MCL double- and triple-strand reconstructions. Double strands reproduced the sMCL and posterior oblique ligament and triple-strands the sMCL, dMCL, and posterior oblique ligament. The sMCL was placed 5 mm posterior to the epicondyle in the double-strand technique and at the epicondyle in the triple-strand technique. Kinematic changes were examined by repeated measures 2-way analysis of variance with posttesting.

RESULTS

Transection of the sMCL, dMCL, and posterior oblique ligament increased valgus rotation (5° mean) and external rotation (9° mean). The double-strand reconstruction controlled valgus in extension but allowed 5° excess valgus in flexion and did not restore external rotation (7° excess). The triple-strand reconstruction restored both external rotation and valgus throughout flexion.

CONCLUSION

In a cadaveric model, a triple-strand reconstruction including a dMCL graft restored native external rotation, while a double-strand reconstruction without a dMCL graft did not. A reconstruction with the sMCL graft placed isometrically on the medial epicondyle restored valgus rotation across the arc of knee flexion, whereas a reconstruction with a more posteriorly placed sMCL graft slackened with knee flexion.

CLINICAL RELEVANCE

An MCL injury may rupture the anteromedial capsule and dMCL, causing anteromedial rotatory instability. Persistent MCL instability increases the likelihood of ACL graft failure after combined injury. A reconstruction with an anteromedial dMCL graft restored native external rotation, which may help to unload/protect an ACL graft. It is important to locate the sMCL graft isometrically at the femoral epicondyle to restore valgus across flexion.

Elongation Patterns of the Superficial Medial Collateral Ligament and the Posterior Oblique Ligament: A 3-Dimensional, Weightbearing Computed Tomography Simulation

Background:

Although length change patterns of the medial knee structures have been reported, either the weightbearing state was not considered or quantitative radiographic landmarks that allow the identification of the insertion sites were not reported.

Purpose:

To (1) analyze the length changes of the superficial medial collateral ligament (sMCL) and posterior oblique ligament (POL) under weightbearing conditions and (2) to identify the femoral sMCL insertion site that demonstrates the smallest length changes during knee flexion and report quantitative radiographic landmarks.

Study Design:

Descriptive laboratory study.

Methods:

The authors performed a 3-dimensional (3D) analysis of 10 healthy knees from 0° to 120° of knee flexion using weightbearing computed tomography (CT) scans. Ligament length changes of the sMCL and POL during knee flexion were analyzed using an automatic string generation algorithm. The most isometric femoral insertion of the sMCL that demonstrated the smallest length changes throughout the full range of motion (ROM) was identified. Radiographic landmarks were reported on an isometric grid defined by a true lateral view of the 3D CT model and transferred to a digitally reconstructed radiograph.

Results:

The sMCL demonstrated small ligament length changes, and the POL demonstrated substantial shortening during knee flexion ( P = .005). Shortening of the POL started from 30° of flexion. The most isometric femoral sMCL insertion was located 0.6 ± 1.7 mm posterior and 0.8 ± 1.2 mm inferior to the center of the sMCL insertion and prevented ligament length changes >5% during knee flexion in all participants. The insertion was located 47.8% ± 2.7% from the anterior femoral cortex and 46.3% ± 1.9% from the joint line on a true lateral 3D CT view.

Conclusion:

The POL demonstrated substantial shortening starting from 30° of knee flexion and requires tightening near full extension to avoid overconstraint. Femoral sMCL graft placement directly posteroinferior to the center of the anatomical insertion of the sMCL demonstrated the most isometric behavior during knee flexion.

Clinical Relevance:

The described elongation patterns of the sMCL and POL aid in guiding surgical medial knee reconstruction and preventing graft lengthening and overconstraint of the medial compartment. Repetitive graft lengthening is associated with graft failure, and overconstraint leads to increased compartment pressure, cartilage degeneration, and restricted ROM.

MCL Reconstruction Using a Flat Tendon Graft for Anteromedial and Posteromedial Instability

The main principles of the present medial collateral ligament (MCL) reconstruction techniques are (1) to approximate the natural anatomy and (2) to restore the main passive restraining structures in anteromedial and posteromedial knee instability. Therefore, we describe a technique using a flat tendon graft instead of tubular grafts with point-to-point bone fixation. Moreover, we address the deep MCL, a relevant restraint to anteromedial instability.

High incidence of superficial and deep medial collateral ligament injuries in 'isolated' anterior cruciate ligament ruptures: a long overlooked injury

PURPOSE

In anterior cruciate ligament (ACL) injuries, concomitant damage to peripheral soft tissues is associated with increased rotatory instability of the knee. The purpose of this study was to investigate the incidence and patterns of medial collateral ligament complex injuries in patients with clinically 'isolated' ACL ruptures.

METHODS

Patients who underwent ACL reconstruction for complete 'presumed isolated' ACL rupture between 2015 and 2019 were retrospectively included in this study. Patient's characteristics and intraoperative findings were retrieved from clinical and surgical documentation. Preoperative MRIs were evaluated and the grade and location of injuries to the superficial MCL (sMCL), dMCL and the posterior oblique ligament (POL) recorded. All patients were clinically assessed under anaesthesia with standard ligament laxity tests.

RESULTS

Hundred patients with a mean age of 22.3 ± 4.9 years were included. The incidence of concomitant MCL complex injuries was 67%. sMCL injuries occurred in 62%, dMCL in 31% and POL in 11% with various injury patterns. A dMCL injury was significantly associated with MRI grade II sMCL injuries, medial meniscus 'ramp' lesions seen at surgery and bone oedema at the medial femoral condyle (MFC) adjacent to the dMCL attachment site (p < 0.01). Logistic regression analysis identified younger age (OR 1.2, p < 0.05), simultaneous sMCL injury (OR 6.75, p < 0.01) and the presence of bone oedema at the MFC adjacent to the dMCL attachment site (OR 5.54, p < 0.01) as predictive factors for a dMCL injury.

CONCLUSION

The incidence of combined ACL and medial ligament complex injuries is high. Lesions of the dMCL were associated with ramp lesions, MFC bone oedema close to the dMCL attachment, and sMCL injury. Missed AMRI is a risk factor for ACL graft failure from overload and, hence, oedema in the MCL (especially dMCL) demands careful assessment for AMRI, even in the knee lacking excess valgus laxity. This study provides information about specific MCL injury patterns including the dMCL in ACL ruptures and will allow surgeons to initiate individualised treatment.

LEVEL OF EVIDENCE

III.

Anatomic medial knee reconstruction restores stability and function at minimum 2 years follow-up

PURPOSE

Chronic grade 3 tears of the medial collateral ligament and posterior oblique ligament may result in valgus laxity and anteromedial rotational instability after an isolated or multiligament injury. The purpose of this study was to prospectively analyze the restoration of physiologic medial laxity as assessed on stress radiography and patient reported subjective functional outcomes in patients who undergo an anatomic medial knee reconstruction.

METHODS

This was a prospective study which included patients with chronic (> 6 weeks old) posteromedial corner injury with or without other ligament and meniscus lesions. Pre- and post-operative valgus stress radiographs were performed in 20° knee flexion and functional outcome was recorded as per the International Knee Documentation Committee (IKDC) and Lysholm scores. All patients underwent anatomic medial reconstruction with two femoral and two tibial sockets using ipsilateral hamstring tendon autograft. Simultaneous ligament and meniscus surgery was performed as per the associated injury pattern. All patients were followed up for a minimum of 24 months post-surgery.

RESULTS

Thirty-four patients (23 males, 11 females) were enrolled in the study and all were available till final follow-up of mean 49.7 ± 14.9 months. The mean age was 30.6 ± 7.9 (18-52 years). Two patients had isolated medial sided lesions and 23 had associated ligament injuries. The mean follow up was 49.7 (24-72) months. The mean IKDC score improved from 58 ± 8.3 to 78.2 ± 9.5 (p < 0.001). Post-operatively there were 15 excellent, 11 good and 8 fair outcomes on Lysholm score. The mean pre-operative valgus side-to-side opening improved from 7.5 ± 2.5 mm to 1.2 ± 0.7 mm on stress radiography (p < 0.001).

CONCLUSION

Anatomic reconstruction of the superficial medial collateral and posterior oblique ligaments restore stability in a consistent manner cases of chronic grade 3 instability. The objective functional results, subjective outcomes and measures of static medial stability are satisfactory in the short term.

LEVEL OF EVIDENCE

IV.

How to Report: Knee MRI

The knee is the most commonly examined joint with magnetic resonance imaging (MRI) and, as such, it is the joint that most trainee radiologists start reporting. This article addresses the main pathologies encountered on MRI examination of the knee, outlining the key features to note and report, as well as providing examples of terminology used to describe these findings.

Impact of intraoperative medial collateral ligament injury on outcomes after total knee arthroplasty: a meta-analysis and systematic review

BACKGROUND

As an uncommon but severe complication, medial collateral ligament (MCL) injury in total knee arthroplasty (TKA) may be significantly under-recognized. We aimed to determine whether MCL injury influences postoperative outcomes of patients undergoing TKA.

METHODS

Two independent reviewers searched PubMed, Cochrane Library, and EMBASE from their inception to July 1, 2021. The main outcomes were postoperative function, and secondary outcomes included the incidences of revision and complications.

RESULTS

A total of 403 articles yielded 15 studies eligible for inclusion with 10 studies used for meta-analysis. This study found that there was a statistically significant difference in postoperative functional scores, range of motion (ROM), complications, and revision rates, with adverse outcomes occurring more commonly in patients with MCL injury.

CONCLUSIONS

This meta-analysis highlights the complexity of MCL injury during TKA and shows the impact on postoperative function, joint mobility, complications, and revision. Surgeons need to prevent and put more emphasis on MCL injury during TKA.

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

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.

Medial soft-tissue complex of the knee: Current concepts, controversies, and future directions of the forgotten unit

The medial side of the knee is comprised of ligaments, myotendinous and meniscal structures that work as a unit to stabilize the joint. The superficial medial collateral ligament is its core structure. Still, all elements of the medial side have load-sharing relationships, leading to a cascade of events in the scenario of insufficiency of any of them. Understanding the medial soft tissue structures as part of a unit is of utmost importance because the most common ligaments damaged in knee injuries belong to it. Surprisingly, there is a lack of high-level evidence published around the issue, and most studies focus on the superficial medial collateral ligament, overlooking the complexity of these injuries. Acknowledging the consequences for joint biomechanics and treatment outcomes, interest in this area is growing between researchers. Emerging evidence may become a game-changer in the future management of these injuries. Based on a thorough research of published literature, this review provides a current biomechanical concepts and clinical guidance to treat these injuries.

Medial Collateral Ligament Reconstruction With Dual Adjustable-Loop Suspensory Fixation: A Technique Guide

The purpose of this technique paper is to outline a minimally invasive technique using dual suspensory fixation with adjustable-loop devices for reconstruction of the superficial medial collateral ligament. The femoral fixation is performed through a limited approach at the anatomic origin of the medial collateral ligament, a socket is prepared, and the graft is docked using the adjustable-loop suspensory fixation. The tibial socket is prepared through a separate incision just distal to the pes anserine tendons and drilled medially to laterally perpendicular to the tibial shaft. The graft is tunneled and docked into the tibial tunnel using adjustable-loop cortical suspensory fixation on the far cortex. The knee is cycled through a full arc of motion and stressed in valgus to take initial creep out of the construct. The knee is placed in 30° of flexion and slight varus and final tension is applied to both the femoral and tibial side. With this technique, fixation can be completed with a minimally invasive incision and it allows the ability to tension the graft both on the femoral and tibial side to the desired level, providing a significant advantage over previously used interference screw techniques.