Morphological description of the temporomandibular joint ligaments in domestic pigs.

The temporomandibular joint (TMJ) ligaments play crucial roles in its function or dysfunction. The objective of this study was to describe the macro and microscopic morphology of these ligaments in domestic pigs, aiming to: (1) expand knowledge about the species; (2) provide anatomical references for advancing veterinary therapy and utilizing pigs as animal models in craniofacial research. Heads of young Sus scrofa domesticus were dissected to identify TMJ ligaments. Fragments of these ligaments were collected and processed for subsequent histological analysis with Haematoxylin and eosin staining. The results were qualitatively described. Pigs exhibited a TMJ reinforced by three individualized capsular ligaments: a lateral ligament, attaching to the ventral margin of the zygomatic process of the temporal bone and the lateral margin of the mandibular neck; a caudomedial ligament, attaching to the retroarticular process of the squamous part of the temporal bone and the caudomedial margin of the mandibular neck and a caudolateral ligament, attaching to the ventral margin of the base of the zygomatic process of the temporal bone and the caudal margin of the mandibular neck. The lateral ligament exhibited a greater constitution of dense irregular connective tissue, while the caudomedial and caudolateral ligaments showed a greater constitution of dense regular connective tissue. It is concluded that the TMJ of pigs presents one more ligament than horses, cattle, dogs, cats and what has been described for pigs themselves. We believe these results may contribute to the improvement of veterinary clinical and surgical therapy overall, as well as provide essential morphological information for a better interpretation and application of interspecies results in craniofacial research using pigs as an experimental model, as in the case of humans.

The role of computed tomography with external rotation and dorsiflexion in decision making for acute isolated non-displaced posterior malleolar fractures Bartonícek and Rammelt type II: a prospective study.

PURPOSE: Our objective was to evaluate the syndesmotic and fracture instability using conventional ankle computed tomography (CT) with stress maneuvers. METHODS: A consecutive sample of 123 individuals with an ankle sprain was assessed for eligibility. In total, 33 patients met the inclusion criteria. All patients underwent a magnetic resonance imaging (MRI) and CT scan with stress maneuvers (CTSM). The patterns of ligament tears f were classified using West Point grades I, IIA, IIB, III. Mann-Whitney test was used to test the differences in the numerical variables between injured and uninjured syndesmoses. The Spearman correlation tested the strength of the association between the tibial joint surface involved in posterior malleolus fracture and syndesmotic instability. RESULTS: In MRI, two patterns of syndesmotic ligament injury predominated. A completely torn anterior inferior tibiofibular (AITFL) and interosseous tibiofibular ligaments (ITFL) and a completely torn AITFL were combined with a partially torn ITFL. In the neutral phase CTSM and during the stress phase the median difference of the narrowest tibiofibular distance between injured and uninjured syndesmoses was 0.2 mm (P = 0.057) and 2.3 mm (P < 0.0001), respectively. There was no association between the percentage of involvement of the posterior tibial joint surface in the posterior malleolar fracture and syndesmotic instability as measured with CTSM. CONCLUSION: The conventional computed tomography with external rotation and dorsiflexion represents a reproducible and accurate diagnostic option for detecting syndesmosis instability and fracture instability in acute isolated non-displaced posterior malleolar fractures Bartonícek and Rammelt type II. LEVEL OF EVIDENCE: Prospective study among consecutive patients (Diagnosis); Level of evidence, 2.

Ankle instability in pediatric and adolescent patients diagnosed with lateral malleolus avulsion fracture: Analysis of clinical and functional outcomes of ligament injury repair surgery.

BACKGROUND: Some children and adolescents can develop persistent pain and instability following inversion injuries of the ankle. In these cases, imaging exams could reveal small bone fragments distal to the lateral malleolus. For these patients, regular conservative treatment may not be successful, requiring additional management, which can include surgical treatment. This study aimed to present the short-to-midterm functional and clinical outcomes of a series of 12 pediatric and adolescent patients who underwent ligament repair surgery due to chronic instability associated with the presence of osseous components in the lateral ligaments. METHODS: A review of 12 patients treated with surgical ligament reconstruction of the ankle was evaluated. Clinical and functional evaluations were based on comparing the Visual Analogue Scale (VAS), AOFAS ankle-hindfoot score, and residual symptoms before and after the surgical intervention. RESULTS: Before the reconstructive approach, the mean VAS was 2.41 and the mean AOFAS score was 74.16. After the procedure, the standard VAS declined to zero, and the AOFAS score was 100 in all patients. The mean follow-up was 6.33 months. CONCLUSION: The surgical approach in children and adolescents with symptomatic ankle instability due to the presence of osseous fragments after an initial inversion trauma provided adequate clinical and functional results at short-to-midterm follow-up. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Arthrological reconstructions of the pterosaur neck and their implications for the cervical position at rest.

The lack of any pterosaur living descendants creates gaps in the knowledge of the biology of this group, including its cervical biomechanics, which makes it difficult to understand their posture and life habits. To mitigate part of this issue, we reconstructed the cervical osteology and arthrology of three pterosaurs, allowing us to make inferences about the position of the neck of these animals at rest. We used scans of three-dimensionally preserved cervical series of Anhanguera piscator, Azhdarcho lancicollis and Rhamphorhynchus muensteri for the reconstructions, thus representing different lineages. For the recognition of ligaments, joint cartilages, and levels of overlapping of the zygapophyses, we applied the Extant Phylogenetic Bracket method, based on various extant birds and on Caiman latirostris. We inferred that pterosaur intervertebral joints were probably covered by a thin layer of synovial cartilage whose thickness varied along the neck, being thicker in the posterior region. Ignoring this cartilage can affect reconstructions. According to the vertebral angulation, their neck was slightly sinuous when in rest position. Our analyses also indicate that pterosaurs had segmented and supra-segmented articular cervical ligaments, which could confer stabilization, execute passive forces on the neck and store elastic energy.

Description of the lateral fibulotalocalcaneal ligament in fetal specimens and its potential clinical implications.

PURPOSE: The increase in ankle sprains in children is a reflection of the greater inclusion of this population in sports. This places the calcaneofibular (CFL) and the anterior talofibular (ATFL) ligaments in focus for study. In adults, the presence of arcuate fibers extending between these two ligaments suggests the existence of a new anatomical and functional complex called the lateral fibulotalocalcaneal ligament of the ankle (LFTCL), which can be associated with the persistence of instability of the talocrural joint in ankle sprains. This study aimed to verify the presence of arciform fibers between the CFL and ATFL in human fetuses and to study the topography of the lateral ankle region. METHODS: Forty matched fetal ankles aged between 28 and 38 weeks, fixed in 4% formalin, were macroscopically, chemically and mesoscopically dissected and analyzed in stereoscope. RESULTS: The ATFL was characterized as a capsular ligament consisting of two fascicles (proximal and distal). The CFL was characterized as an extracapsular ligament. The LFTCL complex was verified in all specimens, characterized by the arcuate fibers between the ATFL and the CFL. CONCLUSION: Such results suggest that this functional unit is congenital and that it should be taken into consideration in the treatment of persistent ankle instabilities in the pediatric population.

Hipermovilidad del tercio posterior del menisco lateral secundario a lesión de los ligamentos meniscotibiales. Estudio cadavérico / Hypermobility of the posterior third of the lateral meniscus secondary to injury to the meniscotibial ligaments. Cadaveric study

Introducción: Los meniscos son estructuras semilunares formadas por fibrocartílagos, localizadas entre el fémur y la tibia. El menisco externo es más móvil, debido a sus inserciones a través de los ligamentos meniscotibiales y poplíteomeniscales. El menisco interno tiene un desplazamiento de 2-3 mm comparado con un desplazamiento de 9-10 mm del menisco externo. Se ha descripto en la literatura mundial que la hipermovilidad meniscal es secundaria a lesión de ligamentos poplíteomeniscales (principales estabilizadores), sin embargo, se realizó un estudio cadavérico donde se evidenció que los ligamentos poplíteomeniscales desempeñan un papel secundario. El objetivo de este estudio es demostrar que la lesión de los ligamentos meniscotibiales es la causante de la hipermovilidad meniscal externa.Materiales y métodos: se realizó un estudio cadavérico en 2022 en Arthrex, Naples, Florida, Estados Unidos. Previo a la valoración artroscópica se efectuó la sección de ligamentos meniscotibiales en el tercio posterior del menisco externo, manteniendo los ligamentos poplíteomeniscales y la inserción de la raíz posterior. Posteriormente, se efectuó la valoración artroscópica en la que se vio traslación anterior y superior del tercio posterior del menisco externo y se realizó la fijación meniscal.Resultados: mediante la fijación del tercio posterior del menisco lateral con técnica transósea, en una falla o insuficiencia de los ligamentos meniscotibiales, se logra estabilidad completa del menisco.Conclusión: la estabilidad principal del tercio posterior del menisco lateral está dada por la inserción periférica de los ligamentos meniscotibiales, por lo que la hipermovilidad meniscal externa no se debe a lesión de los ligamentos poplíteomeniscales. Nivel de Evidencia: IV

Introduction: The menisci are semilunar structures formed by fibrocartilage, located between the femur and the tibia. The lateral meniscus is more mobile due to its insertions through the tibial meniscus and popliteal meniscal ligaments. The medial meniscus has a displacement of 2-3 mm compared to a displacement of 9-10 mm for the external meniscus. It has been described in the world literature that meniscal hypermobility is secondary to injury to the popliteal meniscal ligaments (main stabilizers), however a cadaveric study was carried out where it was shown that the meniscal popliteal ligaments play a secondary role. The objective of this study is to demonstrate that injury to the meniscotibial ligaments is the cause of external meniscal hypermobility.Materials and methods: the cadaveric study was carried out in 2022 at Arthrex, Naples, Florida, United States. Prior to the arthroscopic evaluation, section of the meniscotibial ligaments was performed in the posterior third of the lateral meniscus, maintaining the popliteal meniscal ligaments and the posterior root insertion. Subsequently, the arthroscopic assessment is performed, showing anterior and superior translation of the posterior third of the external meniscus, and meniscal fixation is performed.Results: by fixing the posterior third of the lateral meniscus with a transosseous technique, in a failure or insufficiency of the meniscotibial ligaments, complete stability of the meniscus is achieved. Conclusion: the main stability of the posterior third of the lateral meniscus is given by the peripheral insertion of the meniscotibial ligaments, so external meniscal hypermobility is not due to injury to the popliteal meniscal ligaments. Level of Evidence: IV

Diagnostic accuracy of MRI for detection of occult instability of type I anterior to posterior pelvic injuries.

Type I Young and Burgess anterior posterior compression (APC) pelvic injuries have been classically managed non operatively due to theoretical integrity of sacroiliac joint ligaments (SIJL), though examination under anesthesia (EUA) has been proven occult mechanical instability in up to 50% of these injuries.  We sought to determine the diagnostic accuracy of magnetic resonance (MRI) for detection of occult instability on APC-I injuries when compared to EUA. METHODS: Diagnostic test study of prospectively recruited patients admitted with APC-I pelvic injuries between 2015 and 2022. All patients consented to participate in this study were subjected to MRI and EUA. The evaluators of each of these tests were blinded.  On MRI evaluation, SIJL were considered compromised when unilateral injury to anterior SIJL was visualized in three or more consecutive images or in bilateral injuries, when injury to the anterior SIJL in two or more consecutive images on each side was observed. Positive EUA was considered a symphyseal diastasis over 25 mm on stress fluoroscopy. Demographic data was collected as recruited and sensitivity, specificity, accuracy, and positive and negative predictive values were calculated. Confidence interval was set at 95%. EUA was considered the gold standard in statistical analysis. RESULTS: A total of 32 patients mean aged 36 (24-61) years were included. Mean symphyseal diastasis at admission was 17.58 (11 - 25) mm. The median time from injury to EUA was 5 (0-21) days. Positive EUA was observed on 20 patients and 25 patients  presented compromised SIJL. MRI presented a sensitivity of 95% (75.13% - 99.87%), specificity of 50% (21.09% - 78.91%), positive-predictive value of 73% (60.61% to 82.93%), negative-predictive value of 87% (48.66% - 98.08%). CONCLUSION: Injury to SIJL on MRI presented an accuracy of 77% (58.29% - 89.64%) for the detection of occult pelvic instability on EUA.

Risk Factors for Symptomatic Cyclops Lesion Formation after Anterior Cruciate Ligament Reconstruction / Fatores de risco para formação de lesão cyclops sintomática após a reconstrução do ligamento cruzado anterior

Abstract Objective To evaluate the incidence of symptomatic cyclops lesions requiring surgical treatment after anterior cruciate ligament (ACL) reconstruction and to establish possible intraoperative risk factors related to it. Methods Three hundred and eighty-nine patients aged between 18 and 50 years who underwent primary ACL reconstruction were retrospectively evaluated. Patients were divided into groups according to the presence or absence of symptomatic cyclops lesions, and their characteristics were compared. Patients with associated lesions that required additional surgical procedures (except anterolateral extra-articular procedures) were not included. The rate of symptomatic cyclops lesions was recorded and the following parameters were evaluated: age, gender, time from injury to surgery, graft type and diameter, femoral tunnel perforation technique, fixation type, presence of knee hyperextension, preservation of the ACL remnant, associated anterolateral extra-articular procedure, associated meniscal injury and participation in sports. Results 389 patients were evaluated and 26 (6.7%) patients developed cyclops. The patients with and without cyclops lesions did not differ in age, time from injury to surgery, graft type or diameter, surgical technique, femoral fixation method, presence of knee hyperextension, remnant preservation and associated meniscal injury. The group with cyclops lesion had a higher proportion of females (10 (38.4%) vs 68 (18.7%); OR = 2.7; p= 0.015), higher proportion of extra-articular reconstruction (18 (11.8%) vs 8 (3.4%); OR = 3.8; p= 0.001) and higher proportion of sports practice (23 (8.6%) vs 3 (2.5%); OR = 3.6; p= 0.026). Conclusion In our series, 6.7% of the patients required arthroscopic removal of cyclops lesions. Female gender, associated extra-articular reconstruction and sports practice were factors related to this lesion. Remnant preservation had no relationship with cyclops lesion formation.

Resumo Objetivo Avaliar a incidência de lesões cyclops sintomáticas que precisam de tratamento cirúrgico após a reconstrução do ligamento cruzado anterior (LCA) e estabelecer os possíveis fatores de risco intraoperatórios relacionados a elas. Métodos Trezentos e oitenta e nove pacientes com idades entre 18 e 50 anos submetidos à reconstrução primária do LCA foram avaliados de forma retrospectiva. Os pacientes foram divididos em grupos de acordo com a presença ou ausência de lesões cyclops sintomáticas e suas características foram comparadas. Não foram incluídos pacientes com lesões associadas que necessitassem de outros procedimentos cirúrgicos (à exceção de procedimentos extra-articulares ântero-laterais). A taxa de lesões cyclops sintomáticas foi registrada e os seguintes parâmetros foram avaliados: idade, sexo, tempo da lesão à cirurgia, tipo e diâmetro do enxerto, técnica de perfuração do túnel femoral, tipo de fixação, presença de hiperextensão do joelho, preservação do LCA remanescente, associação a procedimento extra-articular ântero-lateral, lesão de menisco associada e participação em esportes. Resultados Dos 389 pacientes avaliados, 26 (6,7%) desenvolveram lesão cyclops. Os pacientes com e sem lesão cyclops não diferiram quanto à idade, tempo da lesão à cirurgia, tipo ou diâmetro do enxerto, técnica cirúrgica, método de fixação femoral, presença de hiperextensão do joelho, preservação do LCA remanescente e lesão de menisco associada. O grupo com lesão cyclops apresentou mais mulheres (10 [38,4%] vs. 68 [18,7%]; razão de probabilidades [OR] = 2,7; p= 0,015), maior proporção de reconstrução extra-articular (18 [11,8%] vs. 8 [3,4 %]; OR = 3,8; p= 0,001) e maior proporção de prática esportiva (23 [8,6%] vs. 3 [2,5%]; OR = 3,6; p= 0,026). Conclusão Em nossa série, 6,7% dos pacientes necessitaram de remoção artroscópica das lesões cyclops. O sexo feminino, a reconstrução extra-articular associada e a prática esportiva foram fatores relacionados a essa lesão. A preservação do menisco remanescente não foi associada à formação de lesões cyclops.

Magnetic resonance imaging of the knee anteromedial quadrant.

OBJECTIVE: This study aims to evaluate the possibility of characterizing an extra-articular thickening in the knee anteromedial quadrant in routine MRI scans. MATERIALS AND METHODS: Firstly, in a pilot study, for a better understanding of this extra-articular thickening trajectory in MRI, polytetrafluoroethylene (PTFE) tubes were attached to the ligament structure topography in two dissected pieces. Afterward, 100 knee MRI studies were randomly selected from our database, and 97 met the inclusion criteria. Two musculoskeletal radiologists interpreted the exams separately. Both had previously studied the ligament in the cadaveric knee MRI with the PTFE tube. RESULTS: The intraobserver and interobserver agreement for the ligament identification was calculated using Cohen's Kappa coefficient. The first radiologist identified the structure in 41 of the 97 scans (42.2%), and the second radiologist in 38 scans (39.2%). The interobserver agreement was substantial, with a Kappa of 0.68 and an agreement of 84.5%. The results suggest that this extra-articular thickening, recently called Anterior Oblique Ligament (AOL) in the literature, is a structure that can be frequently visualized on MRI scans with a high level of interobserver agreement in a relatively large number of exams. CONCLUSION: Therefore, this study indicates that MRI is a promising method for evaluating this anteromedial thickening, and it may be used for future studies of the Anterior Oblique Ligament.

Acute Deltoid Injury in Ankle Fractures: A Biomechanical Analysis of Different Repair Constructs.

BACKGROUND: The importance of the deltoid ligament in the congruency and coupling of the tibiotalar joint is well known. The current trend is to repair it in cases of acute injuries in the context of ankle fractures; however, there is limited information on how it should be reconstructed. The objective of this study was to compare different deltoid ligament repair types in an ankle fracture cadaveric model. METHODS: Sixteen cadaveric foot-ankle-distal tibia specimens were used. All samples were prepared as a supination external rotation ankle fracture model. Axial load and cyclic axial rotations were applied on every specimen using a specifically designed frame. This test was performed without deltoid injury, with deltoid injury, and after repair. The reconstruction was performed in 4 different ways (anterior, posterior, middle, and combined). Medial clear space (MCS) was measured for each condition on simulated weightbearing (WB) and gravity stress (GS) radiographs. Reflective markers were used in tibia and talus, registering the kinematics through a motion analysis system to record the tibiotalar uncoupling. RESULTS: After deltoid damage, in all cases the MCS increased significantly on GS radiographs, but there was no increase in the MCS on WB radiographs. After repair, in all cases, the MCS was normalized. Kinematically, after deltoid damage, the tibiotalar uncoupling increased significantly. All isolated repairs achieved a similar tibiotalar uncoupling value as its baseline condition. The combined repair resulted in a significant decrease in tibiotalar uncoupling. CONCLUSION: Our results show that deltoid repair recovers the tibiotalar coupling mechanism in an ankle fracture model. Isolated deltoid repairs recovered baseline MCS and tibiotalar uncoupling values. Combined repairs may lead to overconstraint, which could lead to postoperative stiffness. Clinical studies are needed to prove these results and show clinically improved outcomes. CLINICAL RELEVANCE: This study helps in finding the optimum deltoid repair to use in an acute trauma setting.

Study of the nerve endings and mechanoreceptors of the medial meniscotibial ligament of the knee: A structural and distribution analysis.

BACKGROUND: The aim of the present study is to describe the morphology and distribution of the nerve endings of the meniscotibial ligament (MTL) of the knee, in order to understand the interaction between the proprioceptive system and knee mechanics. METHODS: Twenty medial MTLs were obtained from deceased organ donors. The ligaments were measured, weighed and cut. Sections (10 mm) were prepared on hematoxylin and eosin-stained slides for analysis of tissue integrity, and 50 mm sections were submitted to immunofluorescence with the protein gene product (PGP) 9.5 as primary antibody and Alexa Fluor 488 as secondary antibody, followed by microscopic analysis. RESULTS: The medial MTL was identified in 100% of the dissections, with average length, width, thickness and weight of 7.07 ± 1.34 mm, 32.25 ± 3.09 mm, 3.53 ± 0.27 mm and 0.67 ± 0.13 g, respectively. The hematoxylin and eosin-stained histological sections exhibited typical ligament structure, with dense well-organized collagen fibers and vascular tissue. All the specimens analyzed contained type I (Ruffini) mechanoreceptors and free (type IV) nerve endings, varying from parallel to intertwined fibers. Nerve endings not classified with different irregular shapes were also found. Most type I mechanoreceptors were found close to the MTL insertions on the tibial plateau, while the free nerve endings were found adjacent to the capsule. CONCLUSION: The medial MTL showed a peripheral nerve structure, primarily type I and IV mechanoreceptors. These findings suggest that the medial MTL is important for proprioception and medial knee stabilization.

Irreducible Posterolateral Knee Dislocation: A Case Report.

CASE: A 62-year-old male patient suffered an irreducible posterolateral knee dislocation after a horse fell on him. The left knee was slightly flexed with a medial dimple sign present. The medial retinaculum, medial patellofemoral ligament, posteromedial corner structures, and vastus medialis obliquus (VMO) muscle were incarcerated in the medial joint. An open reduction and the medial retinaculum and VMO gap were repaired, and the knee was stabilized in an external fixator for 4 weeks. At 32-month follow-up, the patient had almost full knee motion and good subjective outcomes with moderate residual joint laxity. CONCLUSION: Early clinical diagnosis of irreducible knee dislocations and emergent open reduction should be performed to reduce the risk of soft-tissue compromise.

The Potential of Endoscopic Spring Ligament Repair in Flatfoot Reconstruction.

BACKGROUND: Spring ligament fulfills 2 main important functions: one, supporting the head of the talus and stabilizing the talonavicular joint, and the other, maintaining the longitudinal arch by acting as a static support. In this preliminary report, we describe an endoscopic repair for spring ligament injuries with modified portals. METHODS: We performed a retrospective case series study from February 2019 to January 2022. Posterior tibial tendon and/or associated bone deformities were assessed at the same surgical procedure. All patients were ≥18 years old and they had more than 6 months of follow-up. The procedure was performed in 11 patients. Mean age was 46 years (range 18-63). Ten had concomitant bony realignment surgery, and 8 had posterior tibial tendon surgery. RESULTS: In all patients, endoscopic spring ligament repair could be technically done. The modified portals were used in all procedures as described in the surgical technique. Three patients had a superficial lesion, 1 had a rupture <5 mm, 7 had a rupture >5 mm but not a complete rupture through the entire spring ligament. Most of the patients had good clinical results from the surgery that included endoscopic spring ligament debridement and/or repair at 2 years follow up. CONCLUSION: In this small series we found that endoscopy may be an effective technique to diagnose and treat incomplete spring ligament injuries. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Multidirectional Instability in a Neglected Elbow Dislocation Managed with Circumferential Ligament Reconstruction. A Case Report / Instabilidade multidirecional em uma luxação negligenciada do cotovelo gerenciada com reconstrução do ligamento circunferencial. Um relato de caso

Abstract Neglected elbow dislocation is an uncommon condition and its treatment remains challenging. We present a case of a middle-aged woman presenting with neglected elbow dislocation and multi-direction instability in whom open reduction of the elbow joint and circumferential ligamentous reconstruction with a gracilis tendon graft was done. The functional outcome assessed with the Mayo elbow performance index was excellent. This circumferential technique is undoubtedly a viable technique and the indications can be extended to even manage a neglected dislocation. This procedure reduces the need or diminishes the duration of external fixation requirement and thereby encourages early mobilization.

Resumo A luxação negligenciada do cotovelo é uma condição incomum e seu tratamento permanece desafiador. Apresentamos o caso de uma mulher de meia-idade que apresentou luxação negligenciada do cotovelo e instabilidade multidirecional, na qual foi realizada redução aberta da articulação do cotovelo e reconstrução ligamentar circunferencial com enxerto de tendão gracilis. O resultado funcional avaliado com o índice de desempenho do cotovelo de Mayo foi excelente. Essa técnica circunferencial é, sem dúvida, uma técnica viável e as indicações podem ser estendidas para gerenciar até mesmo um deslocamento negligenciado. Este procedimento reduz a necessidade ou diminui a duração da exigência de fixação externa e, assim, incentiva a mobilização precoce.

Analysis of Mechanoreceptors and Free Nerve Endings of the Transverse Carpal Ligament.

Background: The treatment of carpal tunnel syndrome (CTS) by sectioning the transverse carpal ligament (TCL) is not exempt from complications. Some nerve branches may be damaged by the incision. The aim of this study is to identify and map the TCL nerve endings, serving as a guide for sectioning this structure in a zone with less nerve ending density. Methods: Ten TCLs were obtained from fresh frozen cadavers. The TCLs were measured, divided into 3 equal bands (radial, central, and ulnar), and submitted to cryostat sectioning. The sections were subjected to immunofluorescence with the protein gene product (PGP) 9.5 and confocal microscopy analysis. Results: All the specimens contained type I and type IV mechanoreceptors. Neural elements occupied 0.695 ± 0.056% of the ligament area. The density of the neural elements was greater in the radial, followed by the ulnar and central bands, with 0.730 ± 0.083%, 0.686 ± 0.009%, and 0.669 ± 0.031%, respectively. Conclusion: The present findings suggest that the region with the least potential for neural element injury during TCL release is the central third near the transition with the ulnar third. When performed distally to proximally with a slight inclination from the radial to the ulnar, this release compromises the lowest nerve element density. Topographically, the proximal limit of the release is the distal wrist crease, while the distal limit is the intersection of Kaplan cardinal line and the axis of the third webspace.

Anterolateral ligament MRI of the knee in ACL injuries: MRI abnormalities association with instability.

OBJECTIVE: To evaluate anterolateral ligament abnormalities (ALL) at MRI scans and correlate with data from clinical instability tests (Lachman and pivot shift) performed under anesthesia in patients with acute anterior cruciate ligament (ACL) tears. Furthermore, perform multivariate analysis with other variables to isolate the ALL contribution to instability from other abnormalities. METHODS: Retrospective analysis of MRI and instability tests of 95 patients with ACL tears. The ALL was classified as no abnormality, abnormality without discontinuity, and discontinuity. Injuries in other knee ligament structures and menisci were also assessed. Results of instability tests (pivot shift and Lachman) with the patient anesthetized for arthroscopic ACL reconstruction were obtained from the patient database. Statistical analysis was performed using the IBM SPSS 22. RESULTS: ALL abnormalities and iliotibial band (ITB), lateral (LCL), and medial (MCL) collateral ligament injuries showed a statistically significant correlation with the pivot shift test. The ALL MRI abnormalities were associated with the high-grade pivot shift results (p < 0.0005), with an odds ratio of 55.9 for high degrees of pivot shift in patients with abnormal ALL. The logistic model for all variables analyzed with the results of the pivot shift test demonstrated that the ALL was the only variable with a statistically significant correlation in the model (p < 0.0005). CONCLUSION: MRI ALL abnormalities in patients with ACL injuries have a significant association with pivot shift test results in patients under anesthesia. The logistic model for high - grade pivot shift test results demonstrated that ALL abnormalities were the only variable with significant correlation. KEY POINTS: • Evaluating the anterolateral ligament with MRI in acute anterior cruciate ligament injuries is useful to predict higher grades of pivot shift test in the moment of the arthroscopic reconstruction. • An abnormal anterolateral ligament presented an odds ratio of 55 for high degrees of pivot shift. • ALL MRI abnormalities association with knee instability is independent from other internal knee injuries.

Seguridad de los portales para la reparación endoscópica del ligamento calcaneonavicular: estudio cadavérico / Endoscopic Spring ligament repair. Anatomic evaluation of portal safety

Introducción: La lesión del ligamento calcaneonavicular ha sido descrita como una de las causas de la deformidad en el pie plano del adulto. El objetivo de este artículo es describir portales modificados para el diagnóstico y la reparación endoscópica de las lesiones del fascículo superomedial del ligamento calcaneonavicular y evaluar la seguridad de los portales utilizados. Materiales y Métodos:Se llevó a cabo un estudio cadavérico con seis preparados reproduciendo una lesión del fascículo superomedial del ligamento calcaneonavicular con una punta de corte de radiofrecuencia y la posterior reparación endoscópica. Se crearon dos portales modificados para el abordaje. Luego se procedió a la disección anatómica para evaluar la seguridad de los portales en relación con las estructuras anatómicas. El primer portal se realiza inmediatamente proximal a una línea trazada desde la punta del maléolo medial dirigida al centro del talón, el segundo portal se emplaza 0,5 cm proximal a la inserción del tendón tibial posterior en el escafoides por transiluminación. Si es necesario, se coloca un portal accesorio inmediatamente dorsal al tendón tibial posterior a mitad de camino entre los dos portales antes descritos. Resultados:En todos los casos, fue posible la reparación del ligamento con el procedimiento endoscópico. En la disección anatómica de los portales, se observó una distancia promedio a las estructuras vasculonerviosas de 11,83 mm del portal proximal y de 9,66 mm del portal distal. Conclusión: Los portales modificados son seguros y permiten la visualización directa del haz superomedial del ligamento calcaneonavicular y su reparación endoscópica. Nivel de Evidencia: IV

Introduction: Calcaneonavicular ligament injury has been described as a cause of adult flat foot deformity. The objective of this study is to describe modified portals for the diagnosis and treatment of injuries to the superomedial bundle of the calcaneonavicular ligament and to evaluate the safety of the portals used. Materials and Methods: We performed a cadaveric specimen study on 6 feet, where we reproduced a lesion of the superomedial bundle of the calcaneonavicular ligament with a radiofrequency ablation device and repaired it endoscopically. Two modified portals were created for the approach and an anatomical dissection was performed to assess the safety of the portals in relation to the anatomical structures. The first portal was placed immediately proximal to a line drawn from the tip of the medial malleolus toward the center of the heel; the second portal was placed 0.5 cm proximal to the posterior tibial tendon insertion into the navicular bone, guided by transillumination. If needed, an accessory portal was placed halfway between the two previously described portals immediately dorsal to the posterior tibial tendon. Results:In all cases, ligament repair was achieved with the endoscopic procedure. In the anatomical dissection of the portals, we observed an average distance of 11.83 mm from the proximal portal and 9.66 mm from the distal portal to neurovascular structures. Conclusion:Modified portals are safe and allow direct visualization of the superomedial bundle of the calcaneonavicular ligament to perform endoscopic repair. Level of Evidence: IV

Bony structures at the attachment areas of the cruciate ligaments in human knee joints and their clinical significance-studied using the P45 plastination technique / Estructuras óseas en las áreas de inserción de los ligamentos cruzados en las articulaciones de la rodilla humana y su importancia clínica, estudiadas mediante la técnica de plastinación P45

SUMMARY: For treating cruciate ligament injuries, especially for characterizing the mechanics of the tunnel in cruciate ligament reconstruction, correctly understanding the bony information of the attachment area of the cruciate ligaments is significant. We studied 31 knee joints of middle-aged Chinese adults using the P45 sheet plastination technique, focusing on the attachment areas of the cruciate ligaments, especially the bony structures. The trabeculae at the attachment area were distributed radially and extended deep into the medial wall of the lateral condyle of the femur. However, in the anterior part of the intercondylar eminence, the trabeculae of the anterior group were parallelly arranged along the tendinous fibers of the anterior cruciate ligament, while the trabeculae of the posterior group were parallelly arranged along the perpendicular direction of the anterior cruciate ligament fibers. Similarly, at the attachment area of the lateral wall of the medial condyle of the posterior cruciate ligament, the trabeculae extended radially toward the deep medial condyle. Deep in the posterior part of the intercondylar eminence, the trabeculae were arranged longitudinally. In the anterior part of the intercondylar eminence, the trabeculae were parallelly arranged along the perpendicular directions of ligament fibers. The distribution patterns of the trabecular at the attachment areas of the cruciate ligaments at the ends of the femur and tibia were different. This difference should be considered when orthopedic surgeons reconstruct anterior cruciate ligaments.

Para el tratamiento de lesiones de los ligamentos cruzados, especialmente para caracterizar la mecánica del túnel en su reconstrucción, es importante comprender correctamente la información ósea del área de inserción de estos ligamentos. Estudiamos 31 articulaciones de rodilla de individuos chinos, adultos, de mediana edad, utilizando la técnica de plastinación de láminas P45, centrándonos en las áreas de unión de los ligamentos cruzados, especialmente en las estructuras óseas. Las trabéculas en el área de inserción se distribuyeron radialmente y se extendieron profundamente en la pared medial del cóndilo lateral del fémur. Sin embargo, en la parte anterior de la eminencia intercondílea, las trabéculas del grupo anterior estaban dispuestas paralelamente a lo largo de las fibras tendinosas del ligamento cruzado anterior, mientras que las trabéculas del grupo posterior estaban dispuestas paralelamente a lo largo de la dirección perpendicular de las fibras del ligamento cruzado anterior. De manera similar, en el área de inserción en la cara lateral del cóndilo medial del ligamento cruzado posterior, las trabéculas se extendían radialmente y profundas hacia el cóndilo medial. Profundamente en la parte posterior de la eminencia intercondílea, las trabéculas estaban dispuestas longitudinalmente. En la parte anterior de la eminencia intercondílea, las trabéculas estaban dispuestas paralelamente a lo largo de las direcciones perpendiculares de las fibras del ligamento. Los patrones de distribución del tejido óseo trabecular en las áreas de unión de los ligamentos cruzados en los extremos del fémur y la tibia eran diferentes. Estas diferencias deben tenerse en consideración cuando los cirujanos ortopédicos reconstruyen los ligamentos cruzados anteriores.

Outcomes of a Modified Arthroscopic-assisted Reconstruction Technique for Lateral Ankle Instability / Resultados de uma técnica modificada de reconstrução assistida por artroscopia para instabilidade lateral do tornozelo

Abstract Objective The present study assesses the results of a minimally invasive surgical technique for acute and chronic ankle instability management. Methods The present case series study retrospectively evaluated 40 patients undergoing arthroscopic-assisted percutaneous ankle ligament reconstruction from 2013 to 2019. Results The present study included 17 males and 23 females with an average age of 38.3 years old. Postintervention follow-up using American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot scores identified improvement of > 30 points in function and pain control. The most frequently occurring associated injuries were osteochondral (35%). No patient required reintervention or had infection during follow-up. Conclusion The technique in the present study is easy and achieves satisfactory results for function and pain control. Level of Evidence IV.

Resumo Objetivo O presente estudo avalia os resultados de uma técnica cirúrgica minimamente invasiva para o manejo da instabilidade aguda e crônica do tornozelo. Métodos O presente estudo de uma série de casos avaliou retrospectivamente 40 pacientes submetidos à reconstrução percutânea assistida por artroscopia do ligamento do tornozelo entre 2013 e 2019. Resultados O estudo incluiu 17 homens e 23 mulheres com idade média de 38,3 anos. O acompanhamento pós-intervenção utilizou a pontuação American Orthopaedic Foot and Ankle Society (AOFAS, na sigla em inglês). As pontuações do tornozelo-retropé identificaram melhora > 30 pontos na função e no controle da dor. As lesões associadas mais frequentes foram as osteocondrais (35%). Nenhum paciente precisou de reintervenção ou teve infecção durante o acompanhamento. Conclusão A técnica do presente estudo é fácil e consegue resultados satisfatórios para a função e o controle da dor. Nível de Evidência IV.

Are the popliteofibular ligament, the arcuate ligament, and the fibular insertion of the popliteus muscle the same structure? An anatomic and terminological study.

Lesions in the lateral region of the knee can result in severe disability due to instability and articular degeneration. The structures in the posterolateral side of the knee function as a unit contributes to rotation and translation limits. Anatomical descriptions of the lateral corner of the knee are incomplete and contradictory. This study aims to verify, through anatomical dissections in cadavers, if the fibular insertion of the popliteus muscle, the arcuate ligament, and the popliteofibular ligament are distinct or the same structure with different terminology and descriptions in the literature. Fifteen cadavers were dissected. Photographs were taken, and in some cases, a video was recorded. Also, the correct terminology for ligament and insertion was searched. The dissections allowed the popliteus muscle to be identified proximally in the lateral femoral condyle, in the fibula head's posterolateral region, and through a meniscocapsular insertion. In none of the anatomy books reviewed, this fibular insertion of the popliteus muscle is mentioned. However, our findings and data from other experimental studies provide evidence of its presence. The aponeurotic portion of the arcuate ligament is distinguished from the short lateral ligament, which is the fibular insertion of the popliteus muscle with its tendinous attachment. Therefore, the term popliteofibular ligament should be abandoned based on the anatomic terminology, and the term "fibular insertion of the popliteus muscle" should be used instead.