Bone marrow edema at ligament insertion is an accurate MRI sign of deltoid ligament injury.

BACKGROUND: Magnetic resonance imaging (MRI) is effective in diagnosing deltoid ligament (DL) injury but its sensitivity in chronic cases is low. Additional diagnostic signs are required to reduce the risk of a false negative diagnosis. PURPOSE: To evaluate the added diagnostic value of bone marrow edema at the ligament insertion (BMELI) of DL to the MRI assessment of chronic DL injury. MATERIAL AND METHODS: One hundred patients who consecutively came to our institution between November 2018 and December 2021 and underwent arthroscopic surgery for chronic ankle instability (CAI) were enrolled in the present study. Preoperative MR images were retrospectively reviewed by two orthopedic surgeons to evaluate the sensitivity, specificity and interobserver reliability of three MRI signs in diagnosing chronic DL injury, namely, abnormal ligamentous morphological characteristics (ALMC), BMELI and medial clear space (MCS). RESULTS: Taking arthroscopy as the reference standard, there were 34 patients with and 66 without DL injury. ALMC had 64.71% (22/34; 46.47-79.70) sensitivity and 83.33% (55/66; 71.71-91.00) specificity, BMELI had 70.59% (24/34; 52.33-84.29) sensitivity and 95.45% (63/66; 86.44-98.82) specificity and MCS had 26.47% (9/34; 13.51-44.65) sensitivity and 92.42% (61/66; 82.50-97.18) specificity. Compared with ALMC, BMELI had similar efficacy in superficial cases (P = 0.06) and greater efficacy in deep cases (P = 0.04). All three signs showed good interobserver agreement (kappa values all above 0.7). CONCLUSION: BMELI can reliably indicate concomitant injury to the DL in CAI patients. Using BMELI as a sign of chronic DL injury when ALMC is unclear may reduce the risk of a false negative diagnosis.

Utility of Magnetic Resonance Imaging for Ligamentous Injury in Cervical Spine Trauma: A 2-Year Consecutive Case Cohort.

BACKGROUND: Magnetic resonance imaging (MRI) is increasingly used as an adjunct to spinal soft tissue evaluation in cervical spine (C-spine) trauma; however, the utility of this information remains controversial. In this consecutive observational study, we reviewed the utility of MRI in patients with C-spine trauma. METHODS: We identified patients in real time over a 2-year period as they presented to our level 1 trauma center for C-spine computed tomography (CT) scan followed by MRI. MRI was obtained by the trauma team prior to the spine service consultation if (1) they were unable to clear the C-spine according to protocol or (2) if the on-call radiologist reported a concern for ligamentous integrity from the CT findings. RESULTS: Thirty-three patients, including 19 males (58%) and 14 females, with a mean age of 54 years, were referred to the spine service for concerns of ligamentous instability. The most common mechanisms of injury were motor vehicle accidents (n = 13) and falls (n = 11). MRI demonstrated ligamentous signal change identified by the radiologist as potentially unstable in all patients. Fifteen patients (45%) had multiple C-spine ligaments affected. The interspinous ligament was involved most frequently (28%), followed by the ligamentum flavum (21%) and supraspinous ligament (15%). All patients underwent dynamic upright C-spine X-rays that were interpreted by both the ordering surgeon and radiologist. There was no evidence of instability in any patient; concurrence between X-ray interpretation was 100%. The cervical collar was successfully removed in all cases. No patients required late surgical intervention, and there were no return visits to the emergency department of a spinal nature. CONCLUSIONS: MRI signal change within the ligaments of the C-spine should be interpreted with caution in the setting of trauma. To physicians less familiar with spinal biomechanics, MRI findings may be perceived in an inadvertently alarming manner. Bony alignment and, when indicated, dynamic upright X-rays remain the gold standard for evaluating the ligamentous integrity of the C-spine.

Editorial Commentary: When Properly Indicated, Combined Tibial Tubercle Osteotomy Reduces Risk of Recurrent Patellofemoral Instability More Than Does Isolated Medial Patellofemoral Ligament Reconstruction.

Clinical recognition and surgical treatment of patellofemoral instability has evolved dramatically over the past 3 decades. However, few patellofemoral patients present with an isolated medial patellofemoral ligament (MPFL) tear. Rather, patients often demonstrate patella alta, increased tibial tubercle to trochlear groove (TT-TG) distance, dysplasia, coronal malalignment, or combinations thereof. Given this, concomitant procedures such as tibial tubercle osteotomy (TTO) have become increasingly popularized, given their ability to anteriorize, medialize, and even distalize the patella to correct tracking. It is generally recommended that concurrent TTO be considered with primary medial patellofemoral ligament reconstruction (MPFLR) in patients with closed physes whose TT-TG distance is larger than 17 to 20 mm. MPFLR + TTO is generally safe and may decrease risk of revision surgery when compared with isolated MPFLR in properly indicated patients. However, it important to measure both knee rotation angle and tibial tubercle lateralization on magnetic resonance imaging, as both factors influence TT-TG. In patients in whom abnormal knee rotation angle is felt to be the primary driver of TT-TG, surgeons should proceed with caution when considering concomitant TTO. The pen may be mightier than the sword, but the osteotome may be mightier yet than the scalpel.

Concomitant anterior medializing osteotomy and MPFL reconstruction improves patellar tilt when compared to MPFL reconstruction alone.

PURPOSE: Understanding how surgical procedures influence anatomic factors associated with patellofemoral instability can help guide surgeons when planning treatments for individual patients. This study sought to understand how patellar tilt is affected in adolescent patients with elevated pre-operative tibial tuberosity to trochlear groove (TT-TG) values undergoing medial patellofemoral ligament reconstruction (MPFLR) with or without an anterior medializing osteotomy (AMZ). METHODS: Utilizing a prospective database of 274 patellofemoral instability patients who underwent MPFLR ± AMZ by one of two orthopedic surgeons at a single institution, those who underwent MPFLR + AMZ were identified. Pre-operative and post-operative magnetic resonance imaging (MRI) were used to measure TT-TG distance, while radiographs were used to measure patellar tilt (tilt). Patients were matched based on age at surgery (within 2 years) and pre-operative TT-TG distance (within 2 mm) to a comparison cohort of patients who underwent isolated MPFLR (iMPFLR) without osseous procedures. RESULTS: A total of 56 patients were analyzed (28 per group). The mean age of the cohort was 15.5 ± 2.0 years and was similar between both groups (15.9 ± 1.9 versus 15.1 ± 2.0 years [n.s]). When comparing the two cohorts, significant pre- to post-operative decreases in patellar tilt for both MPFLR + AMZ (6.6 degrees, p < 0.001) and iMPFLR (3.9 degrees, p = 0.013) were noted. While there were no differences in pre-operative patellar tilt (21.2 ± 3.5 versus 21.1 ± 3.4 [n.s]), post-operatively, MPFLR + AMZ had significantly less patellar tilt than iMPFLR (13.2 ± 5.5 versus 16.5 ± 4.4, p = 0.017). CONCLUSIONS: This study found that patellar tilt significantly improved in participants undergoing either MPFLR + AMZ or iMPFLR. In addition, those undergoing MPFLR + AMZ were found to have significantly lower post-operative tilt than those undergoing iMPFLR. If patellar tilt is found pre-operatively to be significantly elevated and a risk for future dislocations, these findings suggest that surgeons might strongly consider MPFLR with AMZ to further address the increased tilt. LEVEL OF EVIDENCE: III.

Magnetic resonance imaging of the ankle: Pathology of the anterior and medial compartments.

Magnetic resonance imaging (MRI) is the gold standard for imaging the tendons and the ligaments of the ankle. MRI combines excellent tissue contrast and accurate anatomic delineation of joint structures. In this pictorial essay, the first of two parts, we delineate the ankle into anatomic compartments and use this as a template for describing pathology in each compartment.

Intrameniscal degeneration and meniscotibial ligament loosening are associated factors with meniscal extrusion of symptomatic discoid lateral meniscus.

PURPOSE: This study aimed to compare the amount of extrusion of the discoid lateral meniscus (DLM), which was symptomatic and required surgery, with normal meniscuses and asymptomatic DLMs and examine factors associated with the extrusion of symptomatic DLM. METHODS: Medical records of participants with DLM or normal lateral meniscus (LM) were retrospectively reviewed using magnetic resonance imaging (MRI). DLM cases were divided into symptomatic and asymptomatic groups. The midbody meniscal extrusion was measured using mid-coronal MRI. The association between meniscal extrusion and MRI findings, including the meniscofemoral ligament, meniscotibial ligament (MTL), intrameniscal signal intensity of the peripheral rim, meniscal shift, and skeletal maturity, was evaluated. RESULTS: Eighty-six knees with DLM (63 symptomatic) were included. The control group included 31 patients. The symptomatic group showed significantly greater meniscal extrusion (mean ± standard deviation symptomatic DLM: 1.0 ± 1.1 mm, asymptomatic DLM: 0.1 ± 0.4 mm, and normal LM: 0.3 ± 0.6 mm, P < 0.001) and had a significantly higher incidence of MTL loosening (P = 0.02) and intrameniscal signal (P < 0.001) than the other two groups. In the symptomatic group, multivariable linear regression analysis showed that MTL loosening [ß = 1.45, 95% confidence interval (CI) 1.03-1.86, P < 0.001] and intrameniscal signal (ß = 0.49, 95% CI 0.09-0.90, P = 0.002) were independent associated factors. CONCLUSIONS: LM extrusion was significantly more common in patients with symptomatic DLM than in those with asymptomatic DLM or a normal LM. MTL loosening and intrameniscal high-signal intensity on MRI were independently associated with meniscal extrusion. These findings help explain the pathogenesis and diagnosis of symptomatic DLM. LEVEL OF EVIDENCE: III.

Investigating the association between COL1A1 and COL3A1 gene variants and knee joint laxity and ligament measurements.

BACKGROUND: Joint laxity is a multifactorial phenotype with a heritable component. Type I collagen gene (COL1A1) mutations cause connective tissue disorders with joint hypermobility as a clinical feature, while variants within COL1A1 and type III collagen gene (COL3A1) are associated with musculoskeletal injuries. The aim of this study was to investigate whether COL1A1 and COL3A1 variants are associated with measurements of non-dominant knee joint laxity and computed ligament length changes. METHODS: 106 moderately active uninjured participants were assessed for genu recurvatum, anterior-posterior tibial translation, external-internal tibial rotation and calculated ligament length changes during knee rotation. Participants were genotyped for COL1A1 rs1107946, rs1800012 and COL3A1 rs1800255. FINDINGS: The COL1A1 rs1107946 GG genotype had significantly larger external rotation [GG: 5.7° (4.9°;6.4°) vs GT: 4.6° (4.2°;5.5°), adjusted P = 0.014], internal rotation [GG: 5.9° (5.3°;6.6°) vs GT: 5.4° (4.7°;6.2°), adjusted P = 0.014], and slack [GG: 18.2° ± 3.2° vs GT: 16.1° ± 3.1°, adjusted P = 0.014]. The GG genotype at both COL1A1 variants had significantly larger active displacement [GG + GG: 6.0 mm (3.8 mm;8.0 mm) vs other genotype combinations: 4.0 mm (2.5 mm;6.0 mm), P < 0.001] and maximum displacement [GG + GG: 8.0 mm (6.9 mm;10.6 mm) vs other genotype combinations: 6.0 mm (5.0 mm;9.0 mm), P = 0.003]. COL1A1 rs1107946 significantly contributed to increased external and internal rotation in multilinear regression models, while both COL1A1 variants, significantly contributed to increased active displacement and slack. Larger medial and lateral cruciate ligament length changes were reported in participants with GG genotypes at both COL1A1 variants. INTERPRETATION: These findings suggest that the COL1A1 variants are associated with knee rotational laxity and changes in ligament length.

[Reality of care of patella stabilizing operations : A status quo among active members of the German Society for Orthopedic and Trauma Surgery (DGOU)]. / Versorgungsrealität patellastabilisierender Operationen : Ein Status quo unter aktiven Mitgliedern der Deutschen Gesellschaft für Orthopädie und Unfallchirurgie (DGOU).

BACKGROUND: Patellofemoral instability is one of the most common pathologies of the knee joint. The planning and implementation of patella-stabilizing operations are very variable. With regard to the operative measures, the preoperative planning is of decisive importance, especially with regard to the complexity of underlying pathologies. OBJECTIVES: The aim of this study was to depict the current healthcare reality in relation to planning and implementation of patella stabilizing operations in Germany. Furthermore, it was to be ascertained whether automated analysis options would facilitate the planning and implementation of surgical procedures (in primary and revision cases). MATERIALS AND METHODS: An online survey with 16 questions was collected by email among all active members of the German Society of Orthopedic and Trauma Surgery. 7974 members were surveyed; 393 responses could then be analyzed. RESULTS: MPFL-reconstruction (89.8%) is the most frequently performed procedure, followed by tibial tubercle transfers (64.9%), osteotomies (51.2%), and trochleoplasty (19.9%). The choice of surgical approach is mainly based on a combination of clinical and radiological findings (90.3%). MRI imaging (81.2%), standard X­ray images (77.4%), and full leg images (76.6%) are mainly used for operative treatment decisions. 59.3% of the respondents would appreciate better preoperative planning and 59.0% would implement more radiologically detectable parameters in their individual preoperative planning if these were automatically available. CONCLUSIONS: The findings of this survey among members of the DGOU identify the MPFL-reconstruction as the central operative approach in the treatment of patellofemoral instabilities, whereas MRI imaging is the diagnostic tool of choice. Future establishment of automated software-based analysis methods could allow a large number of surgeons to expand the radiological parameters taken into account when planning patella-stabilizing operations.

Attachment Type, Thickness, and Volume of the Posterior Meniscofemoral Ligament and Meniscal Pathology.

Several studies have investigated the relationship between the thickness of the posterior meniscofemoral ligament (pMFL) and the presence of a discoid meniscus. We investigated the correlation between meniscal pathology and anatomic features of pMFL such as attachment type, thickness, and volume. We retrospectively evaluated 191 patients who underwent knee MRI. MR images were reviewed to assess the attachment type of the pMFL on the medial femoral condyle (high vs. low), the thickness of the pMFL, and the presence of a meniscal tear or a discoid meniscus. The pMFL volume was quantified by using three-dimensional (3D) segmentation software. The relationship between the frequency of medial or lateral meniscal tear and anatomic features of pMFL were analyzed using Chi-square, Fisher's exact, or Mann-Whitney U test. High type pMFLs had significantly greater thickness and volume than low type pMFLs (p < 0.001). Patients with degenerative lateral meniscal tear had significantly higher thickness and volume of the pMFL than patients with intact lateral meniscus (p < 0.05). The pMFL thickness and volume were not significantly related to traumatic lateral meniscal tear, medial meniscal tear, and discoid meniscus. High type pMFLs tended to be thicker and larger than low type pMFLs and higher thickness and volume of the pMFL was significantly related to the degenerative lateral meniscal tear. However, the attachment type of the pMFL itself was not significantly related to the lateral meniscal tear as well as the medial meniscal tear.

Diagnosis of joint invasion in patients with malignant bone tumors: value and reproducibility of direct and indirect signs on MR imaging.

OBJECTIVES: To evaluate the performance and reproducibility of MR imaging features in the diagnosis of joint invasion (JI) by malignant bone tumors. METHODS: MR images of patients with and without JI (n = 24 each), who underwent surgical resection at our institution, were read by three radiologists. Direct (intrasynovial tumor tissue (ITT), intraarticular destruction of cartilage/bone, invasion of capsular/ligamentous insertions) and indirect (tumor size, signal alterations of epiphyseal/transarticular bone (bone marrow replacement/edema-like), synovial contrast enhancement, joint effusion) signs of JI were assessed. Odds ratios, sensitivity, specificity, PPV, NPV, and reproducibilities (Cohen's and Fleiss' κ) were calculated for each feature. Moreover, the diagnostic performance of combinations of direct features was assessed. RESULTS: Forty-eight patients (28.7 ± 21.4 years, 26 men) were evaluated. All readers reliably assessed the presence of JI (sensitivity = 92-100 %; specificity = 88-100%, respectively). Best predictors for JI were direct visualization of ITT (OR = 186-229, p < 0.001) and destruction of intraarticular bone (69-324, p < 0.001). Direct visualization of ITT was also highly reliable in assessing JI (sensitivity, specificity, PPV, NPV = 92-100 %), with excellent reproducibility (κ = 0.83). Epiphyseal bone marrow replacement and synovial contrast enhancement were the most sensitive indirect signs, but lacked specificity (29-54%). By combining direct signs with high specificity, sensitivity was increased (96 %) and specificity (100 %) was maintained. CONCLUSION: JI by malignant bone tumors can reliably be assessed on preoperative MR images with high sensitivity, specificity, and reproducibility. Particularly direct visualization of ITT, destruction of intraarticular bone, and a combination of highly specific direct signs were valuable, while indirect signs were less predictive and specific. KEY POINTS: • Direct visualization of intrasynovial tumor was the single most sensitive and specific (92-100%) MR imaging sign of joint invasion. • Indirect signs of joint invasion, such as joint effusion or synovial enhancement, were less sensitive and specific compared to direct signs. • A combination of the most specific direct signs of joint invasion showed best results with perfect specificity and PPV (both 100%) and excellent sensitivity and NPV (both 96 %).

Repair of a Reverse Humeral Avulsion of the Glenohumeral Ligament and a Supraspinatus Tear in a Division I Collegiate Football Player: A Case Report.

CASE: We present the case of a 21-year-old male, collegiate division I wide receiver, with a humeral avulsion of the posterior glenohumeral ligament (RHAGL) and near-full-thickness supraspinatus tear after falling on his outstretched arm. He returned to full collegiate participation with symptom resolution after arthroscopic repair of each tear. CONCLUSION: This case report emphasizes the importance of imaging studies in the diagnosis of RHAGL and details a treatment approach that provided an excellent result in a young, active patient. This information will bring attention to these rare injuries and provides reference for providers who encounter patients with similar symptoms or pathology.

Derotational distal femoral osteotomy yields satisfactory clinical outcomes in pathological femoral rotation with failed medial patellofemoral ligament reconstruction.

PURPOSE: The purpose of this study was to evaluate the clinical outcomes of de-rotational distal femoral osteotomy (DDFO) in patients who underwent primary medial patellofemoral ligament reconstruction (MPFLR) failure with increased femoral anteversion along with high-grade J sign. METHODS: Between 2011 and 2019, 14 patients underwent DDFO revision surgery due to failed MPFLR. The pre- and postoperative J sign grade, Caton-Deschamps index (CDI), tibial tuberosity-trochlear groove (TT-TG) distance, femoral anteversion angle (FAA), patellar lateral tilt angle (PLTA), MPFL graft laxity, and patient-reported outcomes (Kujala, Lysholm, Tegner, and International Knee Documentation Committee (IKDC) subjective scores) were collected. The anterior-posterior and proximal-distal distances between the actual point and the Schöttle point were also calculated. RESULTS: Fourteen patients underwent MPFLR revision by DDFO combined with MPFLR. The mean PLTA improved from 40.7° ± 11.9° to 20.5° ± 8.7° (P < 0.001). The mean FAA significantly decreased from 42.7° ± 12.0° to 14.1° ± 5.2° (P < 0.001). The mean patellar laxity index (PLI) decreased from 82.4% preoperatively to 15.1% postoperatively (P < 0.001). None of these patients experienced subluxation or re-dislocation during follow-up of 29.7 ± 5.0 months after revision surgery. Meanwhile, the Tegner score at the last follow-up ranged from 3 to 6, with a median of 5. The Kujala, Lysholm, and IKDC subjective scores showed significant improvements, from a mean of 51.0 ± 6.8 preoperatively to 75.4 ± 5.1 postoperatively (P < 0.001), 49.2 ± 7.9 to 75.2 ± 7.2 (P < 0.001), and 42.9 ± 6.2 to 76.8 ± 6.0 (P < 0.001), respectively. The proportion of patients with a high-grade J sign was significantly lower postoperatively than preoperatively (100% vs. 14%). Four out of 14 patients (29%) showed femoral tunnel mal-positioning. CONCLUSION: MPFLR revision by DDFO combined with MPFLR achieved favorable clinical outcomes in patients with increased femoral anteversion along with high-grade J sign. LEVEL OF EVIDENCE: IV.

Proposed Grading System for Posterior Atlantooccipital Membrane Complex Injuries on Cervical Magnetic Resonance Imaging.

BACKGROUND: The posterior atlantooccipital membrane complex consists of the posterior atlantooccipital membrane and posterior atlantoaxial membrane. Posttraumatic, posterior atlantooccipital membrane complex injuries may have varied appearances on cervical magnetic resonance imaging. The purpose of this study was to identify the different types of posterior atlantooccipital membrane complex injuries that occur in trauma patients. METHODS: Patients who suffered a posterior atlantooccipital membrane complex injury were identified retrospectively using key word searches of cervical magnetic resonance imaging reports between 2013 and 2020 using Nuance mPower software. All relevant imaging studies were reviewed by 2 neuroradiologists. A description of the location and type of posterior atlantooccipital membrane complex injury was recorded, along with additional osteoligamentous trauma of the craniocervical junction and relevant clinical history. RESULTS: Forty-one patients were identified with acute posterior atlantooccipital membrane complex injury. Four distinct patterns of posterior atlantooccipital membrane complex injury were observed. CONCLUSIONS: A grading system for posterior atlantooccipital membrane complex injuries is proposed on the basis of these data: grade 1-edema confined to the posterior atlantooccipital and atlantoaxial membrane; grade 2-edema confined to the posterior atlantooccipital and atlantoaxial membrane and ligamentum nuchae; grade 3-stripping injury of the posterior atlantooccipital membrane with C1-C2 dorsal epidural hematoma; and grade 4-frank disruption of the posterior atlantooccipital membrane at C1 with edema in the remaining posterior atlantooccipital membrane complex.

An Unrecognized Ligament and its Ossification in the Craniocervical Junction: Prevalence, Patient Characteristics, and Anatomic Evidence.

BACKGROUND: In the craniocervical junction, the ligaments between the anterior foramen magnum and the anterior arch of the atlas are not well defined, and ossification of the ligaments in this region has rarely been reported. Characterizing the anatomy and ossification of these ligaments may help in the diagnosis and treatment of disorders in this region. QUESTIONS/PURPOSES: (1) What is the prevalence of an unrecognized ossification at the craniocervical junction in patients with cervical spine disorders, and what are the patient characteristics associated with this ossification? (2) Do patients with this ossification have a greater risk of ossification of other structures at the craniocervical junction or cervical spine? (3) Is there an unreported ligament at this ossified site? METHODS: We conducted a retrospective study of 578 hospitalized patients who underwent CT for cervical spine disorders between January 2016 and July 2020. Based on the inclusion criteria, 11% (66 of 578) were excluded because of a cervical or craniocervical tumor, deformity, infection, fracture or dislocation, or prior surgery, leaving 89% (512 of 578) for analysis. These 512 patients had diagnoses of cervical radiculopathy, cervical myelopathy, cervical spondylotic amyotrophy, cervical spinal cord injury without a radiographic abnormality, or axial neck pain. Their mean age was 57 years (range 22-90 years), and 60% of the patients were men. Patient characteristics including age, gender, and diagnosis were retrieved from a longitudinally maintained institutional database. CT images were used to assess the presence of a previously unrecognized ossification and ossification of other structures in the craniocervical junction and cervical spine, including the posterior longitudinal ligament, anterior longitudinal ligament, nuchal ligament, ligamentum flavum, transverse ligament, and apical ligament, as well as diffuse idiopathic skeletal hyperostosis (DISH). The association between these structures was also assessed. This unreported ossification was called the capped dens sign. It was defined and graded from 1 to 3. Grade 3 was defined as the typical capped dens sign. Cervical spine MRI was used to assess whether there was an unreported structure in the same region as where the capped dens sign was detected on CT images. In the database of a recent study, there were 33 patients younger than 41 years. Nine percent (three of 33) were excluded because they did not have cervical spine MRI. MRIs of the remaining 30 patients were assessed. Their mean age was 35 years (range 22-40 years), and 58% were men. All cervical spine CT images and MRIs were reviewed by one senior spine surgeon and one junior spine surgeon twice with a 2-week interval. Blinding was accomplished by removing identifying information from the radiographs and randomly assigning them to each examiner. Any discrepancy with respect to the grade of the capped dens sign was adjudicated by a third blinded senior spine surgeon. Intrarater and interrater reliabilities were assessed by calculating weighted kappa statistics. No ligament or membrane was reported at this site. MRI is not sensitive to identify thin tissue in this region, especially when severe degeneration has occurred. A cadaveric study was conducted to discover a potential ligament between the inferior margin of the foramen magnum and the anterior arch of the atlas, as prompted by the newly discovered ossification in the clinical analysis of this study. Six embalmed human cadaveric craniocervical regions (three male and three female cadavers; median age 56 years, range 45-78 years) were dissected by a senior anatomist and a senior anatomy technician. A mid-sagittal section of the craniocervical junction was created, allowing us to explore the interval between the anterior foramen magnum and anterior arch of the atlas. A histologic analysis was conducted in two of the six cadavers (a male cadaver, 45 years; and a female cadaver, 51 years). Slides were made with 4-µm sections and stained with hematoxylin and eosin. RESULTS: A novel capped dens sign was detected in 39% (198 of 512) of the patients and the most typical capped dens sign was detected in 19% (96 of 512) of patients. The prevalence of this sign was the highest in patients with cervical spondylotic amyotrophy (12 of 25 patients). The prevalence of ossification of the anterior longitudinal ligament, ligamentum nuchae, and apical ligament, as well as DISH, was higher in patients with a capped dens sign than in those without (p = 0.04, p < 0.001, p < 0.001, and p = 0.001, respectively). The capped dens sign was identified in 69% (18 of 26) of the patients with DISH. A thin and short band-like structure or osteophyte was detected on MRI in 87% (26 of 30), in the same region as the capped dens sign. In the cadaveric study, an unreported, distinct ligamentous structure was identified at this ossified site. It originated from the posterosuperior rim of the anterior arch of the atlas to the inferior margin of the foramen magnum, which we called the inter-atlanto-occipital ligament. It was found in all six dissected craniocervical junctions. The histologic analysis revealed dense connective tissue. CONCLUSION: More than one-third of the patients in this series demonstrated CT evidence of a previously unrecognized ossification in the craniocervical junction, which we called the capped dens sign. Anatomic evidence of this sign, which was a previously unidentified ligament, was also newly discovered in this region. This study was conducted among Asian patients and specimens. Further studies among diverse ethnic groups may be needed to generalize the results. An additional well-designed prospective study will be needed to provide further evidence regarding the potential pathophysiology and clinical relevance of the capped dens sign. Furthermore, the cadaveric analysis in this study was only a preliminary report of the ligament; further biomechanical research is needed to investigate its function. CLINICAL RELEVANCE: Knowledge of this novel ligament may improve the diagnosis and treatment of craniocervical stability and dislocation. Ossification of this ligament is correlated with age, cervical spondylotic amyotrophy, and DISH. We wonder whether patients with cervical degenerative disorders who also have a capped dens sign may be at risk for the formation of osteophytes of an uncovertebral joint, which may result in palsy of the upper limb muscles. The capped dens sign may be the craniocervical manifestation of DISH. This possible association between the capped dens sign and DISH should be considered when performing surgery on patients with the capped dens sign.

Potential Link between Ossification of Nuchal Ligament and the Risk of Cervical Ossification of Posterior Longitudinal Ligament: Evidence and Clinical Implication from a Meta-Analysis of 8429 Participants.

OBJECTIVE: The aim of the present paper was to evaluate the strength and the magnitude of the association between ossification of the nuchal ligament (ONL) and the risk of cervical ossification of the posterior longitudinal ligament (COPLL) and to determine whether there is a direct association or whether COPLL is a consequence of shared risk factors. METHODS: Medline, Web of Science, Cochrane Library, and Embase databases were searched for studies evaluating the association of COPLL-ONL published before July 2020. Eligible studies were selected based on certain inclusion and exclusion criteria. Two investigators independently conducted the quality assessment and extracted the data, including study designs, countries, patients' age, gender, body mass index (BMI), and the risk of COPLL between individuals with and without ONL. A meta-analysis of homogenous data, a sensitivity analysis, a publication bias assessment, and a subgroup analysis were performed using Stata 12.0 software. RESULTS: A total of 10 cohort studies involving 8429 participants were incorporated into this analysis. Pooled results demonstrated a statistically significant association between the presence of ONL and the increased COPLL risk (odds ratio [OR] 3.84; 95% confidence interval [CI] 2.68-5.52, P < 0.001). Furthermore, subgroup analyses indicated that this association was independent of study design (6.36-fold in case-control studies vs 3.22-fold in cross-sectional studies), sex (6.33-fold in male-female ratio >2.5 vs 2.91-fold in male-female ratio <2.5), age (4.28-fold in age ≥55 years vs 3.45-fold in age <55 years), and BMI (3.88-fold in BMI ≥ 25 kg/m2 vs 2.43-fold in BMI < 25 kg/m2 ), which also indicated that obese, older male patients with ONL had a higher risk of OPLL. Moreover, combined two articles revealed that patients with larger-type ONL had a significantly higher risk of long-segment COPLL compared with controls (OR 1.86; 95% CI 1.41-2.47, P < 0.001). CONCLUSION: This is the first meta-analysis to demonstrate a strong and steady association between ONL and higher risk of COPLL. This association was independent of sex, age, and BMI. Considering that ONL is generally asymptomatic and easily detectable on X-ray, our findings implied that ONL might serve as an early warning sign of the onset of COPLL and provide clinicians an opportunity for early detection and early intervention.

Relationship between Anatomical Risk Factors, Articular Cartilage Lesions, and Patient Outcomes Following Medial Patellofemoral Ligament Reconstruction.

OBJECTIVE: The purpose of this study was (1) to determine which risk factors for patellar instability were associated with the presence of patellofemoral cartilage lesions and (2) to determine how cartilage lesion presence, size, and grade affect postoperative disease-specific quality of life. DESIGN: Preoperative, intraoperative, and postoperative demographic, anthropometric (body mass index, Beighton score, hip rotation), radiographic (crossover sign, trochlear bump), cartilage lesion morphology (presence, size, location, grade), and outcomes data (Banff Patella Instability Instrument 2.0 [BPII 2.0]) were prospectively collected from patients undergoing isolated medial patellofemoral ligament reconstruction. For all knees (n = 264), single and multivariable logistic regression was used to determine if any patellar instability risk factors affected the odds of having a cartilage lesion. In patients with unilateral symptoms (n = 121), single variable linear regression was used to determine if the presence, size, or ICRS (International Cartilage Regeneration & Joint Preservation Society) grade of cartilage lesions could predict the 12 or 24+ month postoperative BPII 2.0 score. RESULTS: A total of 84.5% of knees had patellofemoral cartilage lesions (88.3% involved the distal-medial patella). Trochlear dysplasia (high grade: odds ratio = 15.7, P < 0.001; low grade: odds ratio = 2.9, P = 0.015) was associated with the presence of a cartilage lesion. The presence, size, and grade of cartilage lesions were not associated with 12 or 24+ month postoperative BPII 2.0 scores. CONCLUSIONS: Trochlear dysplasia was a risk factor for the development of patellofemoral cartilage lesions in this patient population. Cartilage lesions most commonly involve the distal-medial patella. There was no significant relationship between patellofemoral cartilage lesion presence, size, or grade and postoperative BPII 2.0 scores in short-term follow-up.

Acute, isolated and unstable syndesmotic injuries are frequently associated with intra-articular pathologies.

PURPOSE: Although simultaneous arthroscopy for the surgical treatment of acute isolated, unstable syndesmotic injuries has been recommended, little knowledge is present about the actual frequency of intra-articular pathologies for this injury. The aim of this study was to investigate the frequency and severity of intra-articular pathologies detected during arthroscopy and their subsequent treatment in acute isolated, unstable syndesmotic injuries. METHODS: A retrospective chart review of patients treated by arthroscopic-assisted stabilization for acute isolated, syndesmotic instability was performed. The primary outcome parameter was the frequency of intra-articular pathologies. Secondary outcome parameters were the type of syndesmotic lesion (ligamentous/bony), severity of chondral lesions, MRI findings, treatment details, complications and the identification of factors associated with intra-articular pathologies. RESULTS: Twenty-seven patients, 19% female, with a mean age of 37 ± 12 years met the inclusion criteria. 70% suffered isolated ligamentous injuries, the remaining suffered avulsion fractures of the syndesmosis. Chondral lesions occurred in 48% (ICRS grade II: 33%; ICRS grade IV 15%) and intra-articular loose bodies in 11% of patients. Overall, arthroscopy revealed intra-articular pathologies necessitating further treatment in 19% of patients. Neither the type of syndesmotic injury (bony vs. ligamentous; ns) nor the degree of ligamentous instability (West Point IIB vs. III; ns) had a significant influence on the occurrence of chondral lesions. One complication (SSI) occurred. Pre-operative MRI revealed a sensitivity/specificity of 100/79% for chondral lesions and 50/93% for loose bodies. CONCLUSION: Intra-articular pathologies in acute isolated, unstable syndesmotic injuries occur in up to 50% of patients, 19% necessitated additional treatment. Simultaneous arthroscopy, independent of the pre-operative MRI findings, appears reasonable in highly active patients. LEVEL OF EVIDENCE: Level III.

The tibiocalcaneal bundle of the deltoid ligament - Prevalence and variations.

INTRODUCTION: A precise understanding of the anatomy of the multiple bundles of the deltoid ankle ligament might have clinical impact. The most relevant deltoid anatomical series report a variable frequency of the tibiocalcaneal ligament, possibly the most important bundle to be reconstructed in medial ankle insufficiency. Our purpose was to access the deltoid's tibiocalcaneal ligament morphology in a large anatomical study as well as to perform a historical literature review on the reasons for its variable prevalence. MATERIALS AND METHODS: Forty-three ankle specimen were dissected to describe the prevalence of superficial and deep deltoid bundles, with special attention to the tibiocalcaneal ligament and its variants. RESULTS: All ankles had distinct deep and superficial bundles. In all 43 ankles the tibionavicular and tibiospring ligaments were clearly identified. The superficial posterior tibiotalar ligament was identified in 38 ankles (88%). The deep anterior tibiotalar bundle was identified in 35 ankles (81%). The deep posterior tibiotalar bundle was identified in all ankles. The tibiocalcaneal ligament was identified in 33 ankles (77%). In ten ankles there wasn't a direct bundle between the tibia and the sustentaculum tali. In all of these, however, we found some fibers spanning the gap between the tibiospring ligament and the sustentaculum tali. CONCLUSION: The tibiocalcaneal ligament is present in most specimens. In those in which we could not identify a direct bundle between the tibia and the calcareous we found a variant of the tibiospring ligament that connects to the sustentaculum tali.

Femoral and tibial bone bruise volume is not correlated with ALL injury or rotational instability in patients with ACL-deficient knee.

PURPOSE: Some researchers have suggested that bone bruises are evidence of rotational instability. The hypothesis was that the extent of lateral bone edema is correlated with the presence of an anterolateral ligament (ALL) injury. The main objective was to determine whether there was a correlation between the presence of an ALL injury the extent of bone bruises. METHODS: A prospective diagnostic study enrolled all the patients who suffered an acute anterior cruciate ligament (ACL) who were operated on within 8 weeks. The extent of bone bruising according to the ICRS classification was measured on preoperative MRIs by two independent blinded raters twice with an interval of 4 weeks. Dynamic ultrasonography (US) to look for ALL injury and the pivot shift test were performed before the ACL surgery. The correlation between ALL injury and bone bruises, and the correlation between an ALL injury and a high-grade pivot shift test were determined. RESULTS: Sixty-one patients were included; 52% of patients had an ALL injury on US. The extent of lateral bone bruise was not related to the presence of an ALL injury, nor related to the presence of a high-grade pivot shift. A grade 2 or 3 pivot shift was significantly correlated with an ALL injury (p < 0.0001). Inter- and intra-rater reliability for the bone bruise rating was excellent. CONCLUSION: The extent of lateral bone bruise is not correlated with ALL injury or a high-grade pivot shift; thus, it is not correlated with rotational instability of the knee. LEVEL OF EVIDENCE: II.

Dorsal Atlantoaxial Ligament Hypertrophy as a Cause for Clinical Signs in Dogs with Dens Abnormalities.

The objective of this study is to suggest clinical and subclinical atlantoaxial (AA) instability as a cause for dorsal AA ligament hypertrophy responsible for clinical signs in dogs with dens abnormalities. Clinical information from five dogs with malformed dens and dorsal spinal cord compression at the AA junction was collected. All dogs had neck pain, associated with tetraparesis in three cases. Radiological examination revealed hypoplastic dens in two dogs and a defect in its ossification in the other three. Stress views were able to demonstrate obvious AA instability only in two cases, but it was suspected in the other owing to response to surgical fixation of the joint and the presence of a dorsal compressive band, which was considered an enlarged dorsal AA ligament. Surgical and histopathological examination of compressive tissue confirmed hypertrophy of the ligament. Long-term prognosis in the four operated cases, either by dorsal decompression and ventral fixation or by ventral fixation alone, was excellent. A malformed dens can cause subclinical instability, unnoted in dynamic studies. As instability may lead to hypertrophy of joint ligaments, soft tissue changes (specifically dorsal AA ligament hypertrophy) points out this instability and the need for joint fixation if surgical management is required.