Ligament Attachment Sites Research Articles

Osseous Morphology Differences Between Demyelinating and Axonal Subtypes of Charcot Marie Tooth Disease

Category: Midfoot/Forefoot; Basic Sciences/Biologics Introduction/Purpose: Charcot Marie Tooth disease (CMT) is a progressive genetic neurological condition that, despite heterogeneity in genotype and expression, presents with characteristic cavovarus foot deformity consisting of a varus hindfoot with a high arch and valgus forefoot. Bony morphology differences have been identified in CMT but have not been studied between demyelinating and axonal subtypes. Existing work has predominantly utilized automated angle measures from weight-bearing computed tomography (WBCT), which has limitations for describing a complex 3-dimensional deformity. Statistical shape modeling (SSM) from WBCT images is a mathematical tool that can be used to quantify morphology and alignment in foot pathologies. The objective of this study is to use SSM to analyze differences in osseous morphology between demyelinating and axonal subtypes of CMT and controls. Methods: Retrospective chart review identified patients with CMT who had received WBCT scans before any foot or ankle surgery and healthy controls (IRB: 00154634). This yielded 11 WBCT scans in the demyelinating group, 11 scans in the axonal group, and 15 controls. Images were automatically segmented then manually edited and verified. 3-dimensional parts were aligned using an iterative closest point algorithm. A 14 bone SSM was created for the tibia through metatarsals and single-bone SSMs were created for each individual bone. Principal component analysis was used to calculate modes of variation and parallel analysis was used to identify statistically significant modes across the population. Along each mode of variation, PCA component scores between demyelinating, axonal, and control groups were tested for normality then compared with a t-test, Wilcoxon rank sum test, or ANOVA with a Holm-Sidak correction with a significance value of α=0.05. Results: Differences along at least one PCA mode were identified between axonal and demyelinating groups in the tibia, fibula, cuneiforms, and metatarsals (Figure 1). The tibia and fibula showed a shortened medial malleolus and alteration of the attachment sites of the deep transverse faschia and posterior tibio-fibular ligament in the demyelinating group as compared to axonal and control groups. In the cuneiforms, different patterns of variation were evident between subtypes primarily around the attachment sites of cuneo-navicular and cuneo-cuboid ligaments and the plantar Lisfranc ligament. In the first and second metatarsals, differences between subtypes are present in the morphology of the metatarsal heads and at the attachment of the peroneus longus tendon. Conclusion: There are differences in osseous morphology between subtypes of CMT. In the tibia and fibula, these support axonal CMT as a milder presentation that demyelinating CMT. However, different patterns of morphology variation between subtypes in the midfoot suggest a difference in bone adaptation between groups. Studying demyelinating and axonal groups is a simplification of the genetic variability in CMT, and additional work is necessary to characterize differences based on specific mutations. These findings are relevant to surgical planning as soft tissue surgeries may be less effective with bony deformity. Improved characterization of osseous morphology may improve surgical treatment of CMT.

A Recording Method for Sixteen Nonadult Muscle Entheses

ABSTRACT Bioarchaeology lacks a system for recording the morphology of muscle and ligament attachment sites, called entheses, in growing individuals. Such information is useful in investigating factors that affect bone growth and development, including sex, age, puberty, pathology, and activity. This paper presents a standardized recording method for nonadult entheses based on 29 archaeological individuals of archivally known sex and age-at-death, ranging from two to 17 years. This paper (a) assesses the range of osseous changes of 16 entheses in the upper and lower limbs of growing individuals, and (b) presents a scoring method for each enthesis, which is evaluated through inter-and intra-observer comparisons. Nonadult entheses show a wide range of morphological variation. Method reproducibility is established. This method will allow researchers to further investigate factors affecting bone development in nonadult skeletal remains.

Establishment of a uniform histological evaluation method for early stage osteophytes in the destabilization of the medial meniscus mouse model

BackgroundOsteophyte formation is attracting attention as an early-stage pathology of knee osteoarthritis (OA). Although osteophyte formation is understood as a defense response to joint instability, its role and impact on OA remain largely unknown. Many studies have been conducted using the surgical destabilization of the medial meniscus (DMM) mouse model, but there are few standard evaluation methods, especially in the histological evaluation of early-stage osteophytes. The purpose of this study was to establish a reproducible and uniform method for histological evaluation of characteristics of early osteophyte formation in the DMM mouse model. MethodsMale mice were operated with DMM at 12 weeks old and histologically evaluated at 4 days and 1, 2 and 4 weeks after DMM. Osteophyte Width, Osteophyte Area, and Original and Modified Maturity Scores were used to evaluate osteophytes for all sections. ResultsOsteophyte Width, Osteophyte Area and Maturity Scores were all greater anteriorly than posteriorly in the knee joint. The Modified Maturity Score was more strongly correlated with position than the Original Maturity Score, and could be used to evaluate early-stage osteophyte formation. ConclusionThe Modified Maturity Score as well as Osteophyte Width and Area at the section of the anterior cruciate ligament (ACL) attachment site can provide a reproducible evaluation method to histologically assess the early-stage osteophyte formation in the DMM mouse model.

Radiographic Description of Soft Tissue Attachments around the Elbow.

Quantitatively define the radiographic locations of the major soft-tissue attachments about the elbow. In 10 cadaveric elbows, the attachments of the medial ulnar collateral ligament, lateral ulnar collateral ligament, annular ligament, triceps, and biceps were marked with radiopaque spheres. Measurements were made on calibrated AP and lateral fluoroscopic images from known osseous landmarks. On AP radiographs; the anterior bundle of the MUCL (aMUCL) measured 28.6mm (95% CI, 27. 5-29.8mm) from the humeral attachment to the midpoint of the MUCL ridge on the ulna and 14.3mm, (95% CI 13.0-15.5) to the olecranon. The LUCL was 39.9mm (95% CI, 38.6 - 41.1mm) from the humeral attachment to the supinator crest attachment and 8.9mm (95% CI, 8.1-9.8mm) to the lateral epicondyle. On the lateral radiographs, the humeral attachment of the aMUCL to the medial coronoid was 27.1mm (95% CI, 25.9-28.2mm) and 9.3mm (95%CI, 17.5 -21.2mm) to the tip. The LUCL humeral attachment to the supinator crest was 45.4mm (95%CI, 44.1-46.8mm). The LUCL humeral attachment was located 8.9mm (95%CI, 8.0-9.7mm) posterior from the anterior humeral line. The soft-tissue attachments about the elbow were reproducibly demonstrated on radiographs in relation to osseous landmarks and radiographic lines. The radiographic relationships will allow for improved identification of the ligament and tendon attachment sites of the elbow for intraoperative assessment and postoperative evaluation following reconstruction.

Patient-Individualized Identification of Medial Patellofemoral Ligament Attachment Site to Femur Using "CLASS" MRI Sequences.

Malposition of the femoral tunnel during medial patellofemoral ligament (MPFL) reconstruction may increase the risk of recurrence of patellar dislocation due to isometric changes during flexion and extension. Different methods have been described to identify the MPFL isometric point using fluoroscopy. However, femoral tunnel malposition was found to be the cause of 38.1% of revisions due to patellar redislocation. This high rate of malposition has raised the question of individual anatomical variability. Magnetic resonance imaging (MRI) was performed on 80 native knees using the CLASS (MRI-generated Compressed Lateral and anteroposterior Anatomical Systematic Sequence) algorithm to identify the femoral MPFL insertion. The insertions were identified on the MRI views by 2 senior orthopaedic surgeons in order to assess the reliability and reproducibility of the method. The distribution of the MPFL insertion locations was then described in a 2-plane coordinate system and compared with MPFL insertion locations identified with other methods in previously published studies. The CLASS MPFL footprint was located 0.83 mm anterior to the posterior cortex (line 1) and 3.66 mm proximal to the Blumensaat line (line 2). Analysis demonstrated 0.90 and 0.89 reproducibility and 0.89 and 0.80 reliability of the CLASS method to identify the anatomical femoral MPFL insertion point. The distribution did not correlate with previously published data obtained with other methods. The definitions of the MPFL insertion point in the studies by Schöttle et al. and Fujino et al. most closely approximated the CLASS location in relation to the posterior femoral cortex, but there were significant differences between the CLASS method and all 4 previously published methods in relation to the proximal-distal location. When we averaged the distances from line 1 and line 2, the method that came closest to the CLASS method was that of Stephen et al., followed by the method of Schöttle et al. The CLASS algorithm is a reliable and reproducible method to identify the MPFL femoral insertion from MRI views. Measurement using the CLASS algorithm shows substantial individual anatomical variation that may not be adequately captured with existing measurement methods. While further research must target translation of this method to clinical use, we believe that this method has the potential to create a safe template for sagittal fluoroscopic identification of the femoral tunnel during MPFL surgical reconstruction. Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Probabilistic planning for ligament-balanced TKA—Identification of critical ligament properties

Total knee arthroplasty (TKA) failures are often attributed to unbalanced knee ligament loading. The current study aims to develop a probabilistic planning process to optimize implant component positioning that achieves a ligament-balanced TKA. This planning process accounts for both subject-specific uncertainty, in terms of ligament material properties and attachment sites, and surgical precision related to the TKA process typically used in clinical practice. The consequent uncertainty in the implant position parameters is quantified by means of a surrogate model in combination with a Monte Carlo simulation. The samples for the Monte Carlo simulation are generated through Bayesian parameter estimation on the native knee model in such a way that each sample is physiologically relevant. In this way, a subject-specific uncertainty is accounted for. A sensitivity analysis, using the delta-moment-independent sensitivity measure, is performed to identify the most critical ligament parameters. The designed process is capable of estimating the precision with which the targeted ligament-balanced TKA can be realized and converting this into a success probability. This study shows that without additional subject-specific information (e.g., knee kinematic measurements), a global success probability of only 12% is estimated. Furthermore, accurate measurement of reference strains and attachment sites critically improves the success probability of the pre-operative planning process. To allow more precise planning, more accurate identification of these ligament properties is required. This study underlines the relevance of investigating in vivo or intraoperative measurement techniques to minimize uncertainty in ligament-balanced pre-operative planning results, particularly prioritizing the measurement of ligament reference strains and attachment sites.

Investigation of pelvic symmetry: A systematic analysis using computer aided design software

AbstractObjectivesThis study aimed to investigate the symmetry of the Chinese pelvis.MethodsComputed tomography scan images of each of 50 Chinese pelvises were converted to 3D models and the left sides of the pelvises were reflected on Mimics software. Then, the reflected left side model was aligned with the right side using the closest point algorithm function of Geomagic software to perform symmetry analysis. The volume and surface area of either side of the pelvises were also calculated. The mean standard deviation (SD), the mean percentage of permissible deviations within the ±2 mm range, the percentage differences in volume and surface area were measured to compare pelvic symmetry. In addition, the distribution of pelvic bilateral symmetry associated with both age and sex were compared.ResultsThe mean SD was 1.15 ± 0.16 mm and the mean percentage of permissible deviations was 90.82% ± 4.67%. The deviation color maps showed that the specific areas of asymmetry were primarily localized to major muscle or ligament attachment sites and the sacroiliac joint surfaces. There was no significant difference between the bilateral sides of the pelvis in either volume or surface area. Additionally, no difference in any indexes was exhibited in relation to sex and age distribution.ConclusionOur results demonstrated that the pelvis has high bilateral symmetry, which confirmed the potential of using contralateral pelvic models to create fully patient‐specific and custom‐made pelvic implants applicable for the treatment of fracture and bony destruction.

Paleopathology, Entheseal Changes, and Cross-Sectional Geometry: The Zooarchaeology of Working Animals

Morphological changes in the skeletons of working animals such as reindeer, horse, and cattle have long been observed and documented in the archaeological record. Activities such as riding, carrying cargo on their backs, and pulling vehicles like sleds and ploughs throughout an animal’s life history cause alterations and variations to skeletal tissue. Such alterations include paleopatho­logical lesions, entheseal changes (EC)—alterations in muscle, tendon, and ligament attachment sites on bone—and variations in cross-sectional bone geometry (CSBG). These clues are helpful for reconstructing human-animal relationships in faunal remains of our archaeological past. However, other factors influence the morphological appearance of skeletal tissue besides working activities, such as age, sex, body size, nutrition, genetics, environmental factors, and management by human caretakers. This article explores how paleopathological lesions, EC, and CSBG in faunal skeletal remains are examined to reconstruct working activity and changes to human-animal rela­tionships in the archaeological record. In particular, we discuss two primary topics of inquiry: (1) a review of paleopathological identifiers in working animals such as cattle, horse, camel, and rein­deer; and (2) how EC and CSBG are understood in terms of bone functional adaptation, and their application in working and non-working animals such as reindeer and horse. Next, we analyze each topic highlighting their benefits and limitations, including how they contribute to archeolog­ical understandings of human-animal relationships in the past, as well as their implications for future research.

Bayesian parameter estimation of ligament properties based on tibio-femoral kinematics during squatting

The objective of this study is to estimate the, probably correlated, ligament material properties and attachment sites in a highly non-linear, musculoskeletal knee model based on kinematic data of a knee rig experiment for seven specific specimens. Bayesian parameter estimation is used to account for uncertainty in the limited experimental data by optimization of a high dimensional input parameter space (50 parameters) consistent with all probable solutions. The set of solutions accounts for physiologically relevant ligament strain (ϵ<6%). The transitional Markov Chain Monte Carlo algorithm was used. Alterations to the algorithm were introduced in order to avoid premature convergence. To perform the parameter estimation with feasible computational cost, a surrogate model of the knee model was trained. Results show that there is a large intra- and inter-specimen variability in ligament properties, and that multiple sets of ligament properties fit the experimentally measured tibio-femoral kinematics. Although all parameters were allowed to vary significantly, large interdependence is only found between the reference strain and attachment sites. The large variation between specimens and interdependence between reference strain and attachment sites within one specimen, show the inability to identify a small range of ligament properties representative for the patient population. To limit ligament properties uncertainty in clinical applications, research will need to invest in establishing patient-specific uncertainty ranges and/or accurate in vivo measuring methods of the attachment sites and reference strain and/or alternative (combinations of) movements that would allow identifying a unique solution.

Effect of Ligament Mapping from Different Magnetic Resonance Image Quality on Joint Stability in a Personalized Dynamic Model of the Human Ankle Complex

Background. Mechanical models of the human ankle complex are used to study the stabilizing role of ligaments. Identification of ligament function may be improved via image-based personalized approach. The aim of this study is to compare the effect of the ligament origin and insertion site definitions obtained with different magnetic resonance imaging (MRI) modalities on the mechanical behaviour of a dynamic model of the ankle complex. Methods. MRI scans, both via 1.5 T and 3.0 T, were performed on a lower-limb specimen, free from anatomical defects, to obtain morphological information on ligament-to-bone attachment sites. This specimen was used previously to develop the dynamic model. A third ligament attachment site mapping scheme was based on anatomical dissection of the scanned specimen. Following morphological comparison of the ligament attachment sites, their effect on the mechanical behaviour of the ankle complex, expressed by three-dimensional load–displacement properties, was assessed through the model. Results. Large differences were observed in the subtalar ligament attachment sites between those obtained through the two MRI scanning modalities. The 3.0 T MRI mapping was more consistent with dissection than the 1.5 T MRI. Load–displacement curves showed similar mechanical behaviours between the three mappings in the frontal plane, but those obtained from the 3.0 T MRI mapping were closer to those obtained from dissection. Conclusions. The state-of-the-art 3.0 T MRI image analysis resulted in more realistic mapping of ligament fibre origin and insertion site definitions; corresponding load–displacement predictions from a subject-specific model of the ankle complex showed a mechanical behaviour more similar to that using direct ligament attachment observations.

Distal insertion rupture of lateral ankle ligament as a predictor of weakened and delayed sports recovery after acute ligament repair: mid-term outcomes of 117 cases

BackgroundFor lateral ankle ligament rupture, surgical repair has been considered for patients requiring return to high-demanding sports. However, there is a lack of systematic research regarding arthroscopic treatment followed by ligament repair for severe acute ankle sprain. The purpose of this study was to analyze the mid-term outcomes of arthroscopy followed by open anatomic lateral ankle ligament repair surgery for acute lateral ankle sprain and the impact of ligament rupture site on the outcomes.MethodsProfessional or amateur athletes with clinically- and radiologically-confirmed grade III acute lateral ankle ligament injuries undergoing ankle arthroscopy followed by open anatomic ligament repair between June 2007 and May 2017 were reviewed. Intra-articular lesions and the location of rupture were first examined under arthroscopy. Simple suture repair was performed for mid- substance ligament rupture (middle group), while suture repair with anchors were used for the ruptures near the ligament attachment site on the fibular (proximal group), talar or the calcaneal side (distal group). Outcomes were evaluated at final follow-up, including visual analog scale (VAS) pain score, American Orthopaedic Foot & Ankle Society (AOFAS) score, Tegner score, time to return to sports, resumption of pre-injury sports level, sprain recurrence and range of motion (ROM).ResultsA total of 117 patients were included for analysis, with a mean follow-up duration of 46.4 ± 16.1 months. There were 48 (41%) cases in the proximal group, 41 (35%) cases in the middle group and 28 (24%) cases in the distal group respectively. At final follow-up, all of the VAS score, AOFAS score and the Tegner score were significantly improved from the pre-operative level (p < 0.001). 12 (10%) patients complained of sprain recurrence during follow-up. 14 (12%) patients reported mild ROM restriction and 7 (6%) patients experienced transient skin numbness. The average time to return to pre-injury sports was 4.34 ± 1.11 months. The smallest proportion (86% ± 13%) of resumption of pre-injury sports level was reported from the distal group, compared with 93% ± 12% for the proximal group and 89% ± 14% for the middle group (p = 0.037). Time to return to sports was significantly longer for the distal group, with an average of 4.59 ± 1.27 months compared to 3.99 ± 1.09 months for the proximal group and 4.58 ± 0.90 months for the middle group (p = 0.009).ConclusionsAnkle arthroscopy followed by open anatomic ligament repair is a reliable procedure for patients requiring return to high demanding sports after severe acute ankle sprains. Distal rupture near the talar or calcaneal end was associated with delayed return-to-sport and inferior performance in resuming pre-injury sports level.

Entheseal Changes: Benefits, Limitations and Applications in Bioarchaeology

Reconstructing physical activities in ancient humans has long been pursued in bioarchaeology to understand our history and development. Entheseal changes (EC)––variations to muscle, tendon, and ligament attachment sites on bone––have been used in bioarchaeology since the 1980s to reconstruct activities in past populations such as changes in mobility, subsistence strategy, and gendered division of labour. EC research is based on bone functional adaptation, where bone responds to mechanical stress on entheses through bone formation or destruction in varying degrees of expression. However, the relationship between EC and activity is more complex than simple cause-and-effect, as it involves multiple confounding variables, which can affect EC morphology. This article addresses the use of EC research in bioarchaeology through two parts: Part 1 defines entheses and EC, including observational and quantitative methods developed in bioarchaeology to study EC. Part 2 will summarize the main known factors that influence EC beyond activity such as age, sex, and body size. The article concludes with a discussion of varying benefits and limitations to EC research in bioarchaeology including the use of archaeological samples, historical collections, and animal experimental models. Overall, EC research can be difficult to link with activity due to its multifactorial etiology, challenges of efficacy in developing methods, and limitations of working with human remains. However, recent studies are showing more positive results, demonstrating the usefulness of EC as a way to reconstruct activity.

Magnetic resonance imaging of medial collateral ligament avulsion fractures of the knee in children: a potentially underestimated injury.

Literature regarding medial collateral ligament (MCL) injuries is focused on adults with superficial MCL disruptions. However, children follow different injury patterns, with avulsion fractures at ligament attachment sites occurring commonly. Such avulsions have not been characterized for pediatric MCL injuries. To elucidate imaging findings, and review management and outcomes of pediatric MCL avulsion fractures. We conducted a 10-year retrospective review of knee magnetic resonance (MR) imaging reports for patients younger than 16years old diagnosed with acute MCL avulsion fracture. MR imaging was reviewed to confirm and characterize the components of the avulsion (perichondrium without or with cartilage, and/or bone) and to identify additional knee injuries. Radiographs, if available, from the time of injury were reviewed. Clinical management and patient outcomes were recorded. Eighteen patients (13 boys, 5 girls) incurred an acute MCL avulsion fracture. All avulsions involved the deep MCL attachment: 17 meniscofemoral and 1 meniscotibial component. Two avulsions also included the superficial MCL attachment. Nine boys had non-osseous avulsions, all radiographically occult. All girls had radiographically apparent avulsions. Three girls and three boys sustained associated knee derangements, most commonly anterior cruciate ligament (ACL) injury (n=4). All MCL avulsions were initially treated conservatively; one child required subsequent surgery for ongoing pain. Pediatric MCL avulsion fractures in this study uniformly involve the attachment of the deep MCL and can be entirely non-osseous, particularly in boys who lag in skeletal maturity, making these injuries radiographically occult. MR imaging may be required to recognize these avulsions, which can impact the duration of rest and knee bracing.

Biomechanical comparison of arthroscopic and open lunate excisions in the cadaveric wrist

BackgroundIn advanced Kienböck disease, unreconstructible lunate should be excised as a salvage procedure. There is a lack of information about the biomechanical approaches evaluating the carpal kinematics after lunate excision. We hypothesized that arthroscopic lunate excision would not break the ring structure of the proximal carpal row, preventing carpal instability. We aimed to investigate changes in carpal kinematics following arthroscopic and open lunate excisions. MethodsWe used upper extremities from five fresh cadavers and simulated arthroscopic and open lunate excisions. Arthroscopic lunate excision was performed to preserve the attachment sites of intrinsic and extrinsic carpal ligaments to the lunate. Open lunate excision was conducted with sectioning of the intrinsic and extrinsic carpal ligaments. Using a three-dimensional space electromagnetic tracking device, rotation angles of the scaphoid and triquetrum and the change of scaphotriquetrum distance were measured under axial loading. We compared the rotation angles and the change of scaphotriquetrum distance among intact wrists, open, and arthroscopic lunate excisions. FindingsNo Significant differences in the rotation angle of the scaphoid and triquetrum or the change of scaphotriquetrum distance were found between intact wrist and arthroscopic lunate excision. The triquetrum significantly dorsiflexed and supinated in wrists with open lunate excisions compared with intact wrists. Significant differences in the change of scaphotriquetrum distance were found between intact and openly excised wrists and between arthroscopic and open excisions. InterpretationArthroscopic lunate excision potentially prevented kinematic change of the proximal carpal row under axial loading by maintaining the integrity of attachment sites of carpal ligaments.

Patellar Tendon Orientation and Strain Are Predictors of ACL Strain In Vivo During a Single-Leg Jump.

Background:There is little in vivo data that describe the relationships between patellar tendon orientation, patellar tendon strain, and anterior cruciate ligament (ACL) strain during dynamic activities. Quantifying how the quadriceps load the ACL via the patellar tendon is important for understanding ACL injury mechanisms.Hypothesis:We hypothesized that flexion angle, patellar tendon orientation, and patellar tendon strain influence ACL strain during a single-leg jump. Specifically, we hypothesized that patellar tendon and ACL strains would increase concurrently when the knee is positioned near extension during the jump.Study Design:Descriptive laboratory study.Methods:Models of the femur, tibia, ACL, patellar tendon, and quadriceps tendon attachment sites of 8 male participants were generated from magnetic resonance imaging (MRI). High-speed biplanar radiographs during a single-leg jump were obtained. The bone models were registered to the radiographs, thereby reproducing the in vivo positions of the bones, ligament, and tendon attachment sites. Flexion angle, patellar tendon orientation, patellar tendon strain, and ACL strain were measured from the registered models. ACL and patellar tendon strains were approximated by normalizing their length at each knee position to their length at the time of MRI. Two separate bivariate linear regression models were used to assess relationships between flexion angle and patellar tendon orientation and between ACL strain and patellar tendon strain. A multivariate linear regression model was used to assess whether flexion angle and patellar tendon strain were significant predictors of ACL strain during the inflight and landing portions of the jump.Results:Both flexion angle and patellar tendon strain were significant predictors (P < .05) of ACL strain. These results indicate that elevated ACL and patellar tendon strains were observed concurrently when the knee was positioned near extension.Conclusion:Concurrent increases in patellar tendon and ACL strains indicate that the quadriceps load the ACL via the patellar tendon when the knee is positioned near extension.Clinical Relevance:Increased ACL strain when the knee is positioned near extension before landing may be due to quadriceps contraction. Thus, landing with unanticipated timing on an extended knee may increase vulnerability to ACL injury as a taut ligament is more likely to fail.

Enthesitis is a clue to the diagnosis of spondyloarthritis, focus on psoriatic arthritis

Enthesitis is a common clinical feature of spondyloarthritis (SpA), characterized by inflammation of the tendon or ligament attachment site to a bone or joint capsule. The importance of detecting enthesitis for the diagnosis of SpA is confirmed by its inclusion in the classification criteria for psoriatic arthritis (PsA) – CASPAR – and in the classification criteria for SpA of the international group for the study of spondyloarthritis – ASAS. Enthesitis may be the first clinical sign of SpA, as well as the leading symptom that significantly influences the therapeutic choice. Enthesitis occurs in 30–50% of patients with SpA and is associated with high disease activity, more severe pain and worse quality of life. The frequency of enthesitis detected by ultrasound in patients with PsA is approximately 4 times higher than in patients with ankylosing spondylitis and is associated with the severity of the disease. The review presents current data on the pathophysiology, diagnosis and treatment of enthesitis. Recent studies emphasize the role of imaging methods for the diagnosis of enthesitis due to their higher sensitivity and specificity compared to clinical examination. There is very limited information on the effect of synthetic disease-modifying antirheumatic drugs on enthesitis, while targeted drugs and biologic therapy have shown high efficacy in its treatment compared to placebo. Preliminary evidence suggests that targeting interleukin (IL) 17 or IL12/23 may be more effective in enthesises inflammation suppression than tumor necrosis factor α inhibition.

Studies of the criteria for determining optimal location of medial patellofemoral ligament attachment sites.

Identifying appropriate attachment sites is important in the planning of medial patellofemoral ligament (MPFL) reconstruction. Two criteria are advanced to describe normal MPFL function, namely isometric criterion and desired pattern criterion. Subsequently, computational methods have applied these criteria to determine optimal attachment sites. So far, there is no study that compares the outcomes of these two criteria. For five subjects' 3D models of the patella and femur, three patellar sites and many femoral sites were identified as pairs of candidate attachment sites. For each patellar site, the criteria were applied to identify the matching femoral sites that satisfy them. The matching femoral site with the smallest length change was identified as the optimal femoral site. The desired pattern criterion finds fewer matching sites compared to the isometric criterion. In contrast, the isometric criterion can always find matching sites. The optimal femoral sites obtained vary significantly across different subjects. For most subjects, the optimal sites obtained using the isometric criterion are closer to known anatomical sites than those obtained using the desired pattern criterion. This study reaffirms that MPFL reconstruction is subject specific. The isometric criterion may be more reliable than the desired pattern criterion for determining optimal attachment sites. Graphical Abstract. Highlight of the paper. The location of the patella site significantly affects the location of the optimal femoral site. The isometric criterion option 1, with length at 0° regarded as MPFL's natural length, may be more reliable than other criteria or options for the planning of MPFL surgery because the optimal sites that it finds are closest to known anatomical sites.ᅟ.

Magnetic Resonance Imaging of Enthesitis in Spondyloarthritis, Including Psoriatic Arthritis-Status and Recent Advances.

Enthesitis, inflammation at the attachment sites of tendons, ligaments, fascia, and joint capsules to bones plays a critical role in the pathogenesis of spondyloarthritis (SpA), including psoriatic arthritis (PsA). Magnetic resonance imaging (MRI) has aided in a better understanding of pathophysiology, early diagnosis, prognostication, therapeutic outcomes, and follow up of enthesitis. The concept of enthesitis as a focal insertional pathology has transformed over the past decade, with the help of MRI, to a more widespread entity involving both bone and surrounding soft tissues. The utility of MRI in the differential diagnosis of suspected enthesitis has recently been explored. With the emergence of the treat-to-target concept, and a domain-based approach in the management of SpA, objective and sensitive monitoring of response to targeted therapy becomes prudent. Properties like high sensitivity, ability to image intra-osseous pathology along with surrounding structures exemplify the utility of MRI technology. Considering the lack of a comprehensive, validated MRI score the Outcome Measures in Rheumatology (OMERACT) MRI in Arthritis Working Group, informed by a systematic literature review, developed the first international, consensus-based MRI-scoring system, combined with MRI definitions of pathologies for enthesitis in patients with spondyloarthritis (SpA) and PsA. An atlas with representative images of each grade of the scoring system was subsequently developed by the group to aid readers interested in using the heel enthesitis MRI scoring system (HEMRIS). The HEMRIS can find utility in clinical trials targeting enthesitis as the primary outcome. MRI also finds value for global assessment of the total burden of enthesitis. The concept of whole-body MRI (WBMRI), enabling visualization of entheses throughout the body using a single image is relatively new. The MRI whole-body score for inflammation in peripheral joints and entheses (MRI-WIPE) is a promising scoring system, which is undergoing further testing in clinical trials and longitudinal cohorts evaluating global measures of inflammation at entheses. This review discusses the role of MRI in diagnosis and monitoring of enthesitis in SpA and PsA, along with recent advances in the field, based on published literature.

Dynamic Three-Dimensional Computed Tomography Mapping of Isometric Posterior Cruciate Ligament Attachment Sites on the Tibia and Femur: Single- Versus Double-Bundle Analysis

(1) To determine the area of posterior cruciate ligament (PCL) insertion sites on the lateral wall of the medial femoral condyle (LWMFC) that demonstrates the least amount of length change through full range of motion (ROM) and(2) to identify a range of flexion that would be favorable for graft tensioning for single-bundle (SB) and double-bundle (DB) PCL reconstruction. Six fresh-frozen cadaveric knees were obtained. Three-dimensional computed tomography point-cloud models were obtained from 0° to 135°. A point grid was placed on the LWMFC and the tibial PCL facet. Intra-articular length was calculated for each point on the femur to the tibia at all flexion angles and grouped to represent areas for bone tunnels of SB and DB PCLR. Normalized length changes were evaluated. Femoral tunnel location and angle of graft fixation were significant contributors to mean, minimum, and maximum normalized length of the PCL (all p < .001). Tibial tunnel location was not significant in any case (all p < .22). A femoral tunnel in the location of the posteromedial bundle of the PCL resulted in the least length change at all tibial positions (maximum change 13%). Fixation of the anterolateral bundle in extension or at 30° flexion resulted in significant overconstraint of the PCL graft. The femoral tunnel location for a SB PCLR resulted in significant laxity at lower ranges of flexion. PCL length was significantly dependent on femoral tunnel position and angle of fixation, whereas tibial tunnel position did not significantly contribute to observed differences. All PCL grafts demonstrated anisometry, with the anterolateral bundle being more anisometric than the posteromedial bundle. For DB PCLR, the posteromedial bundle demonstrated the highest degree of isometry throughout ROM, although no area of the LWMFC was truly isometric. The anterolateral bundle should be fixed at 90° to avoid overconstraint, and SB PCLR demonstrated significant laxity at lower ranges of flexion. Surgeons can apply the results of this investigation to surgical planning in PCLR to optimize isometry, which may ultimately reduce graft strain and the risk of graft failure. Additionally, DB PCLR demonstrated superiority compared with SB PCLR regarding graft isometry, as significant laxity was encountered at lower ranges of flexion in SB PCLRs. Fixation of the ALB at 90° flexion should be performed to avoid overconstraint in knee extension.

Quantitative and Qualitative Analyses of the Glenohumeral Ligaments: An Anatomic Study

Background: While several studies have qualitatively described the anatomy of the glenohumeral ligaments, there remains a lack of consensus regarding their quantitative humeral and glenoid attachment sites. Purpose: To quantitatively and qualitatively describe the anatomic humeral and glenoid attachment sites of the glenohumeral ligaments and their relationship to well-established anatomic landmarks. Study Design: Descriptive laboratory study. Methods: A total of 10 nonpaired, fresh-frozen human cadaveric shoulders were included in this study. A 3-dimensional coordinate measuring device was used to quantify the location of pertinent bony landmarks and soft tissue attachment areas. All subcutaneous tissues and musculature were removed, with the exception of the rotator cuff (respective muscle bellies cut at their musculotendinous junctions) and the long head of the biceps tendon. The superior glenohumeral ligament (SGHL), middle glenohumeral ligament (MGHL), anteroinferior glenohumeral ligament (AIGHL), posteroinferior glenohumeral ligament (PIGHL), and coracohumeral ligament (CHL) were then transected. Coordinates of points along the perimeters of attachment sites were used to calculate areas, while coordinates of center points were used to determine distances between surgically relevant attachment sites and pertinent bony landmarks. Results: The mean length of the SGHL humeral attachment along the intra-articular cartilage margin was 9.5 ± 3.2 mm, spanning from 12:55 to 1:40, while the SGHL glenoid attachment to the labrum was 1.9 ± 1.2 mm medial to the most lateral extent of the labral rim, spanning from 12:30 to 12:45. The mean length of the MGHL attachment along the intra-articular cartilage margin was 16.4 ± 3.0 mm, equating to 2:10 to 3:35 on the humeral head clockface, and the glenoid attachment was confluent with the labrum, attaching 1.5 ± 1.0 mm medial to the most lateral extent of the labral rim and thus extending from 1:50 to 2:35 on the glenoid clockface. The mean length of the AIGHL attachment along the intra-articular cartilage margin was 12.0 ± 3.0 mm, spanning from 4:05 to 5:10 on the humeral head clockface. The AIGHL bony footprint on the glenoid neck was 48.4 ± 24.5 mm2. The confluent attachment of the AIGHL to the labrum was 1.2 ± 0.9 mm medial to the most lateral extent of the labral rim, corresponding to 3:30 to 4:05 on the glenoid clockface. The mean length of the PIGHL attachment along the intra-articular cartilage margin was 12.0 ± 1.4 mm, spanning from 7:40 to 8:50 on the humeral head clockface. The PIGHL attachment to the labrum was 1.2 ± 0.5 mm medial to the most lateral extent of the labral rim. This attachment to the labrum was calculated to span from 7:35 to 8:50 on the glenoid clockface. The mean length of the CHL origin from the coracoid was 12.9 mm, with its most anterior point located a mean of 14.1 mm from the tip of the coracoid. The mean length of the CHL attachment along the intra-articular cartilage margin was 10.0 ± 4.0 mm, spanning from 11:55 to 12:40 on the humeral head clockface. Conclusion: Glenohumeral ligaments were consistently identified in all specimens with minor anatomic variability for the SGHL, MGHL, AIGHL, and PIGHL. Important landmarks including the cartilage surface of the humerus, the bicipital groove, and the clockface can be utilized intraoperatively when attempting anatomic repair of these structures. Clinical Relevance: There are multiple open and arthroscopic shoulder procedures that rely on anatomic restoration of these static stabilizers to provide optimal shoulder function and prevent recurrent instability. The qualitative descriptions are comparable with current literature; however, this study is the first to quantify the glenohumeral capsular and ligamentous attachments. The data provided allow for reliable landmarks to be established from known bony and soft tissue structures.