Capsular attachment on the anterosuperior femoral head-neck junction: A hypothesis about femoroacetabular impingement.

Femoroacetabular impingement (FAI), characterized by a pathological contact between the proximal femur and acetabulum, is a common precursor of hip osteoarthritis. Cam morphology is a bony prominence that causes FAI and frequently forms on the anterosuperior femoral head-neck junction. Despite anatomical consensus regarding the femoral head-neck junction as a boundary area covered by the articular cartilage and joint capsule, it remains unclear whether the joint capsule is continuous with the anterosuperior articular cartilage. For the anatomical consideration of cam morphology formation, this study aimed to investigate the histological characteristics of the capsular attachment on the anterosuperior femoral head-neck junction, particularly focusing on the presence or absence of continuity of the joint capsule to the articular cartilage. A total of 21 anterosuperior regions (seven hips each for the 12:00, 1:30, and 3:00 positions) from seven hips (three males and four females; mean age at death, 68.7 years) were histologically analyzed in this study for quantitative evaluation of the capsular thickness using histological sections stained with Masson's trichrome, as well as qualitative evaluation of the capsular attachment. The present study showed that the joint capsule, which folded proximally to the femoral head-neck junction from the recess, exhibited a blend of the fibrous and synovial regions. Notably, it not only continued with the superficial layer of the articular cartilage, but also attached to the articular cartilage via the fibrocartilage. This continuous region was relatively fibrous with dense connective tissue running in the longitudinal direction. The capsular thickness at the recess point (mean, 1.7 ± 0.9 mm) and those at the distal end of the articular cartilage (0.35 ± 0.16 mm) were significantly greater than the control value for the most superficial layer thickness of the articular cartilage (0.019 ± 0.003 mm) (Dunnett's T3, both p-value <0.001). Based on the fibrous continuity between the joint capsule and articular cartilage and its thickness, this study suggests the anatomical possibility that some mechanical stress can be transmitted from the joint capsule to the articular cartilage at the frequent sites of cam morphology.

Preliminary study of extracorporeal shock wave alleviating joint capsule fibrosis caused by internal bleeding of knee joint in rats.

PURPOSE: Joint contracture is a common disease in clinical practice, joint bleeding is an important factor affecting the progression of joint contracture. This study aimed to explore the effect of extracorporeal shock wave on alleviating joint capsule fibrosis caused by intra-articular hemorrhage in rats. METHODS: Forty two SD rats were randomly divided into seven groups. Perform simple fixation and fixation after blood injection separately. Measure the range of motion of each group's knee joints and calculate the corresponding degree of contraction. Use HE staining and Masson staining to detect the number of anterior joint capsule cells and collagen deposition. Detection of changes in Wnt1, ß-catenin protein expression in joint capsule using Western blotting. RESULTS: Compared to group C, the degree of knee joint contracture in M1 and M2 groups of rats increased, and collagen deposition, cell number and Wnt1, ß-catenin protein expression also increased accordingly. Compared to M1 and M2 groups, the degree of knee contraction in E1 and E2 groups were reduced, while collagen deposition, cell number and Wnt1, ß-catenin protein expression were decreased, and the degree of joint contracture in NR1 and NR2 groups showed no significant improvement. Compared to NR1 and NR2 groups, the degree of knee contraction in E1 and E2 groups were reduced, while collagen deposition, cell number and Wnt1, ß-catenin protein expression were decreased. CONCLUSIONS: Both rat models of knee joint contracture were successful, and joint bleeding can exacerbate joint contracture. Extracorporeal shock waves alleviate joint capsule fibrosis caused by intra-articular bleeding in rats.

Is hip capsule morphology associated with hip pain in patients without another structural correlate?

OBJECTIVE: The goals of this study were (i) to assess the association between hip capsule morphology and pain in patients without any other MRI abnormalities that would correlate with pain and (ii) to investigate whether hip capsule morphology in hip pain patients is different from that of controls. METHODS: In this study, 76 adults with hip pain who did not show any structural abnormalities on MRI and 46 asymptomatic volunteers were included. Manual segmentation of the anterior and posterior hip capsules was performed. Total and mean anterior hip capsule area, posterior capsule area, anterior-to-posterior capsule area ratio, and medial-to-lateral area ratio in the anterior capsule were quantified. Differences between the pain and control groups were evaluated using logistic regression models. RESULTS: Patients with hip pain showed a significantly lower anterior-to-posterior area ratio as compared with the control group (p = 0.002). The pain group's posterior hip capsule area was significantly larger than that of controls (p = 0.001). Additionally, the ratio between the medial and lateral sections of the anterior capsule was significantly lower in the pain group (p = 0.004). CONCLUSIONS: Patients with hip pain are more likely to have thicker posterior capsules and a lower ratio of the anterior-to-posterior capsule area and thinner medial anterior capsules with a lower ratio of the medial-to-lateral anterior hip capsule compartment, compared with controls. CLINICAL RELEVANCE STATEMENT: During MRI evaluations of patients with hip pain, morphology of the hip capsule should be assessed. This study aims to be a foundation for future analyses to identify thresholds distinguishing normal from abnormal hip capsule measurements. KEY POINTS: • Even with modern image modalities such as MRI, one of the biggest challenges in handling hip pain patients is finding a structural link for their pain. • Hip capsule morphologies that correlated with hip pain showed a larger posterior hip capsule area and a lower anterior-to-posterior capsule area ratio, as well as a smaller medial anterior capsule area with a lower medial-to-lateral anterior hip capsule ratio. • The hip capsule morphology is correlated with hip pain in patients who do not show other morphology abnormalities in MRI and should get more attention in clinical practice.

Magnetic resonance arthrography with positional manoeuvre for the diagnosis of synovial fold of posterior shoulder joint capsule.

OBJECTIVES: The objective of this study is to prospectively assess the effectiveness of shoulder magnetic resonance (MR) arthrograms with positional manoeuvres in detecting posterior synovial folds. METHODS: Two radiologists independently assessed all axial MR arthrograms in internal rotation, neutral position, and external rotation for the presence of a posterior synovial fold. The diagnostic performances of the MR arthrograms were then compared, with results validated through arthroscopy. RESULTS: Arthroscopy was performed on 81 of the 150 patients included in the study. A posterior synovial fold was identified arthroscopically in eleven of these patients. Measurements of the posterior synovial fold obtained in external rotation and the neutral position of the arm showed a significant correlation with arthroscopic results (p < 0.05). For detecting the posterior synovial fold with arthroscopic correlation, the sensitivity and specificity values for observer 1 and observer 2 were 100-81.4% and 100-88.6%, respectively, for MR arthrograms in the neutral position; 100-52.9% and 100-62.9% for MR arthrograms in external rotation; and 100-95.7% and 81.8-98.6% for MR arthrograms in internal rotation. There was a fair agreement for MR arthrography in external rotation for detecting posterior synovial folds, while MR arthrograms in internal rotation and neutral position showed near-perfect and significant interobserver agreement. CONCLUSION: The rotational positions of the humeral neck during MR arthrographic examination can influence the diagnostic specificity and sensitivity of axial MR arthrograms in detecting the posterior synovial fold. CLINICAL RELEVANCE STATEMENT: The posterior synovial fold can mimic a posterior labral detachment. Therefore, its correct identification is crucial in order to avoid unnecessary surgical procedures. KEY POINTS: Movement of the shoulder may introduce variability in MR arthrography appearance. Rotation of the humeral neck during MR arthrography can affect diagnoses in posterior synovial fold detection. Given that posterior synovial folds can imitate posterior labral detachment, their correct identification is crucial to avoid unnecessary surgical procedures.

In vivo interrelationships between the gluteus minimus and hip joint capsule in the hip internal rotation position with flexion.

BACKGROUND: The flexion adduction internal rotation (FADIR) test is performed by the combined motions of hip flexion (with knee flexion), adduction, and internal rotation, and can often reproduce anterior hip pain consistent with an individual's presenting pain. Since it has high sensitivity for intraarticular pathology diagnosis but low specificity, understanding the extraarticular pathology that can induce anterior hip pain in the FADIR test may also be essential. This study hypothesized that the interrelationships between the joint capsule and gluteus minimus differ in individuals with and without FADIR-positive pain and aimed to elucidate the in vivo interrelationships at hip internal rotation in 90°-flexion, which is also often restricted in individuals with FADIR-positive pain. METHODS: Ten hips were included in the FADIR-positive group, and ten hips without hip pain in the FADIR test were included in a control group. Based on the ultrasound images at the four hip rotation conditions (20° and 10° external rotations, 0° external/internal rotation, and 10° internal rotation), orientation measurements of the gluteus minimus (muscle belly portion) and joint capsule were performed and quantitatively compared between the FADIR-positive and control groups. Additionally, 3 hips of 3 participants were randomly selected from each of the control and FADIR-positive groups for magnetic resonance imaging analysis. RESULTS: At 0°-external/internal and 10°-internal rotation, on ultrasound images, fibers of the gluteus minimus and joint capsule in the FADIR-positive group were significantly more oriented in the same direction than those in the control group. Magnetic resonance imaging showed that the loose connective tissue between the gluteus minimus and joint capsule was prominent at 10°-internal rotation in the control group, although this was not apparent in the FADIR-positive group. CONCLUSIONS: At hip internal rotation in 90° flexion, the muscular belly portion of the gluteus minimus and joint capsule were oriented in the same direction to a greater extent in the FADIR-positive group than in the control group owing to a morphological change in the loose connective tissue between them. The pathological changes in the loose connective tissue may inhibit smooth movement of the gluteus minimus relative to the joint capsule in individuals with FADIR-positive pain.

Imaging evaluation of hip capsule disorders: a comprehensive review.

The hip capsule and capsular ligaments play crucial roles in providing hip stability and mobility. Their role in hip pathologies is being increasingly recognized, underscoring the need for thorough imaging evaluation, which is better performed through MRI-arthrography. Various diseases affect the hip capsule directly or indirectly. Improper mechanical loading, as seen in conditions such as femoroacetabular impingement or chondrolabral pathology, can induce capsule thickening, whereas thinning and laxity of the capsule are characteristics of microinstability. Inflammatory conditions, including adhesive capsulitis of the hip, crystal deposition disease, polymyalgia rheumatica, and infections, also lead to capsular changes. Traumatic events, particularly posterior hip dislocations, cause capsule ligament disruption and may lead to hip macroinstability. Friction syndromes can lead to capsular edema due to impingement of the adjacent capsule. Hip arthroscopy can result in various postoperative findings ranging from fibrotic adhesions to focal or extensive capsule discontinuation. Although the significance of hip capsule thickness and morphology in the pathogenesis of hip diseases remains unclear, radiologists must recognize capsule alterations on imaging evaluation. These insights can aid clinicians in accurately diagnosing and effectively managing patients with hip conditions.

The tibial capsular reflection and septum in posterior compartment are safe and reliable soft-tissue landmark for tibial tunnel drilling in posterior cruciate ligament reconstruction.

PURPOSE: To investigate the validity of using tibial capsular reflection and septum in the posterior compartment as landmark during posterior cruciate ligament (PCL) reconstruction (PCLR). METHODS: Anatomic measurements were obtained for 12 fresh human cadaveric knee specimens to observe the spatial position of the tibial insertion of the PCL in relation to the posterior septum and the capsular reflection in the posterior compartment. Sixty patients who underwent reconstruction of the PCL between 2020 and 2023 were also retrospectively investigated. The tibial tunnel was replaced in all patients using the same method (with reference to the tibial capsular reflection and the posterior septum). The placement of the tibial tunnel was assessed using X-ray fluoroscopy intraoperatively and computed tomography and three-dimensional reconstruction postoperatively. RESULTS: All fibres in the tibial insertion of the PCL in the 12 cadaveric specimens were located in the posteromedial compartment, adjacent to the posterior septum. The inferior border of the PCL insertion is adjacent to the tibial capsular reflection, which is attached at the champagne glass drop-off of the posterior tibia. In our previous cases, none of the patients experienced postoperative or intraoperative complications such as neurovascular injury, and the angle between the pin and the PCL facet was 93.1 ± 3.9° as measured on intraoperative radiographs. The mean distance from the centre of the tibial tunnel outlet to the inferior border of the PCL insertion was 5.6 ± 1.1 mm, and the distance from the centre of the tibial tunnel outlet to the outer border of the PCL insertion as a percentage of the length of the inferior border of PCL insertion was 42.2 ± 6.3%. CONCLUSION: The tibial capsular reflection and septum in the posterior compartment are safe and reliable soft-tissue landmark for tibial tunnel drilling in PCLR. LEVEL OF EVIDENCE: Level Ⅳ.

Matrix metalloproteinase-1 and matrix metalloproteinase-9 are highly expressed in the joint capsule of diabetic frozen shoulder.

BACKGROUND: The pathophysiology of frozen shoulder (FS) involves abnormal expressions of matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases (TIMPs) that lead to capsular fibrosis. However, there has been little concern for why diabetic FS has more protracted fibrotic condition. The objective of this study was to compare the expression levels of MMPs and TIMPs in the joint capsule of patients with diabetic and nondiabetic FS. MATERIALS AND METHODS: Samples of capsular tissue were collected from 20 patients with FS (10 diabetic patients; diabetic group and 10 nondiabetic patients; nondiabetic group) and 10 patients (control group) with chronic anterior shoulder instability. Quantitative real-time reverse transcriptase-polymerase chain reaction and Western blot analysis were performed to determine the expression levels of mRNA and protein for MMP-1, 3, 9, 13, 14, and TIMP-1, 2. RESULTS: The results of quantitative real-time reverse transcriptase-polymerase chain reaction showed significantly higher expression levels of all MMPs and TIMP-1 and significantly lower expression levels of TIMP-2 in the joint capsule of patients in the diabetic or nondiabetic groups compared with the control group. Significantly higher expression levels of MMP-1, 9, 14, and TIMP-1 were detected in the diabetic group compared with the nondiabetic group. The results of Western blot analysis showed significantly higher levels of MMP-3, 13, 14, and TIMP-1 in the joint capsule of patients in the diabetic or nondiabetic groups compared with the control group. However, no significant differences of protein levels of them were observed between diabetic and nondiabetic groups. CONCLUSIONS: The findings of this study demonstrate the potential involvement of MMP-1 and 9 in the pathophysiology of diabetic FS. These findings may be helpful in identification of therapeutic targets for development of novel treatments for this protracted chronic fibrosing condition.

Downregulation of IL-11 regulates the TGFß/ERK1/2 signaling pathway to inhibit articular capsule fibrosis and alleviate post-traumatic articular capsule contracture.

BACKGROUND: Post-traumatic capsular contracture is a common complication of joint injury and surgery. Post-traumatic capsular contracture is associated with fibrosis characterized by excessive differentiation and proliferation of myofibroblasts and abnormal secretion and accumulation of extracellular matrix. Previous studies have suggested that IL11 plays a role in myocardial fibrosis. We thus hypothesized that IL11 may play a fibrotic role during capsular contracture, in order to discover new targets for preventing joint capsule contracture METHODS: We constructed a post-traumatic contracture model by excessively extending the knee joint and fixing the joint in the flexion position, and a post-traumatic joint capsule contracture model was constructed in the wild-type, IL11-/-, IL11R -/-, α-SMA-cre-IL11fl/fl, α-SMA-cre-IL11Rfl/fl mouse strain, with wild-type mice without any treatment of the knee joint as the control group. Fibrotic markers and the expression of IL11 and IL11R in knee joint tissue were detected in each group of mice. The NIH3T3 cell line was used for in vitro analyses. The expression of fibrosis markers, IL11, TGFß and ERK1/2 were detected by western blot, ELISA and RT-qPCR. RESULTS: Inhibition of IL11 inhibited ERK1/2 phosphorylation, reduced the secretion of collagen in the joint capsule, and inhibited the excessive differentiation and proliferation of myofibroblasts in the post-traumatic joint capsule contracture, thus alleviating the joint capsule contracture and obtaining better joint mobility. CONCLUSION: Downregulation of IL11 in traumatic joint capsule contracture inhibits ERK1/2 phosphorylation, thus significantly relieving joint capsule contracture. Our findings indicate the TGFß/IL11/ERK1/2 axis is an important pathway for the differentiation of fibroblasts into myofibroblasts. Anti-IL11 treatment is an effective means to prevent traumatic joint capsule contracture.

A new injection method for identifying the subpopliteal recess of the knee.

The posterolateral region of the knee has a complex and diverse anatomy. Hydrarthrosis of the knee can potentially communicate with other parts of the joint space. The joint fluid distribution reflects anatomical communications between synovial spaces. To observe the continuity between the knee joint cavity and the surrounding bursa, we devised a dissection method with a new injection agent, an eosin-containing congealed liquid that spreads uniformly over the entire space. The purpose of this study was to perform a detailed examination of the subpopliteal recess (SPR) where a bursa connects to the knee joint capsule. We also reported the advantages of this new injection agent compared with conventional materials (latex and epoxy resin). Twenty-two formalin-fixed cadavers (34 knees), two N-vinyl-pyrrolidone (NVP)-fixed cadavers (4 knees), and two cadavers (3 knees) fixed by Thiel's method were used. After filling the knee joint space and SPR with eosin congealed liquid, the specimens were dissected to investigate the morphology of the SPR. In addition, three different types of injection agents were assessed. The SPR extended distally along the popliteus tendon. The SPR length was 22.64 ± 11.38 mm from the upper end of the lateral tibial condyle to the lower end of the depression. The existence of a fabellofibular ligament made the SPR significantly longer, but abrasion of the femoral articular cartilage did not affect the SPR. Furthermore, the relationship between the popliteus muscle and the SPR was classified into three types (types 1-3). Types 2 and 3 in which the SPR extended to the proximal tibiofibular joint may cause instability of the knee joint. The eosin congealed liquid was highly useful in many aspects, such as fluidity and injection workability. The new dissection method with eosin congealed liquid provides insights into the anatomy of the posterior lateral knee, which are useful for radiological diagnoses and clinical treatments.

Arthrographic description of the canine carpal joint cavities and its recesses.

Joint effusion is diagnostically important. The canine carpal joint effusion, which is sometimes difficult to detect clinically, has received less attention in diagnostic ultrasound (US) studies. The aim of the present study was to provide a description of the morphological appearance of the canine carpal joint cavities and recesses using US, radiography, helical computed tomography (CT) and three-dimensional volume rendering technique (3D-VRT) images and to prove the applicability of musculoskeletal US for the detection of artificial carpal joint effusion in dogs. The understanding of the characteristics of these structures in normal patients is essential in the diagnosis. Twenty-eight clinically and radiologically unremarkable canine carpal cadavers of different breeds were examined, representative images were selected and anatomical structures were labelled. The canine carpal joint cavities and in particular its recesses had a complex appearance with a basic structure found in all dogs: Antebrachiocarpal joint: dorsoproximal antebrachiocarpal recess, dorsodistal antebrachiocarpal recess, medial antebrachiocarpal recess, lateral antebrachiocarpal recess and five palmar antebrachiocarpal recesses. Middle carpal joint: two dorsal middle carpal recesses, medial common middle carpal and carpometacarpal recess, lateral common middle carpal and carpometacarpal recess, four palmar middle carpal recesses. The carpometacarpal joint had dorsal and palmar funnel-shaped and irregular, finely tubular extensions, the most prominent ran dorsal to metacarpal III, the maximum distal end represented the proximal metacarpal diaphysis. All recesses presented ultrasonographically as a generalized anechogenic to hypoechoic filled continuation of the articular capsule with an indistinct peripheral hypoechogenic to isoechogenic fine capsule, the synovial-connective tissue interface was difficult to identify. The novel results of this study provide the first morphological description of the ultrasonographic, radiographic and computed tomographic arthrographic appearance of the canine carpal joint cavities and recesses with different injection volumes. The canine carpal joint cavities and in particular its recesses had a complex appearance with a basic structure found in all dogs. The applicability of musculoskeletal US to visualize an artificial carpal effusion has been demonstrated. The results of this study, and in particular US, give the practitioner an advantage in visualizing joint effusion and assist in the decision to perform arthrocentesis.

In vivo movement interrelationships among the medial meniscus, joint capsule, and semimembranosus during tibial rotation.

The meniscal position within the knee is critical to maintain normal knee function. The joint capsule might dynamically coordinate the medial meniscus (MM) by transmitting a semimembranosus action. However, their interrelationships in vivo are unclear. We aimed to determine relationships among the MM, joint capsule, and semimembranosus during passive tibial external-internal and isometric tibial internal rotation at the medial and posteromedial knees of 10 healthy individuals in vivo using ultrasound. We analyzed images of the MM and joint capsule locations at the medial and posteromedial knee and the velocity waveform similarity of each structure during rotational tasks. Both isometric internal rotation with semimembranosus action and passive tibial external rotation displaced the MM inward at the medial knee. The MM and joint capsule during these MM displacements coordinately moved with more than moderate cross-correlation coefficients (passive external and isometric internal rotations, ≥ 0.54 and ≥ 0.90, respectively). The movements of the MM and joint capsule to the semimembranosus during isometric internal rotation also coordinated with moderate cross-correlation coefficients (≥ 0.62). Therefore, the joint capsule might dynamically coordinate the MM by transmitting semimembranosus action. Whether increased tibial internal rotation or semimembranosus shortening causes MM extrusion awaits further investigation.

Transient contribution of the sphenoid ala major to the socket of the temporomandibular joint in near-term fetuses.

The temporomandibular joint (TMJ) is a complex structure that plays a vital role in the movement of the jaw. Some anatomy and dental textbooks show that, at the medial margin, the TMJ capsule attaches to a suture between the sphenoid ala major and the temporal bone squamosa. In near-term fetuses, the ala major extends posterolaterally to approach the TMJ. In this study, we aimed to investigate the contribution of the sphenoid ala major to the socket of the TMJ in near-term fetuses. We examined histological sections from 22 human fetuses (approximately 15-40 weeks). At midterm, the lateral and superior walls of the TMJ cavity were formed by the temporal bone squamosa, whereas the ala major was distant from the joint. However, at near-term, the ala major formed the medial wall of almost the entire part of the joint cavity. The top of the TMJ was attached to both the squamosa and ala major, with the condylar head consistently separated from the sphenoid by the joint disk. We observed a significant descent of the middle cranial fossa in near-term fetuses, which brought the ala major close to the TMJ. This transient position of the TMJ near the sphenoid is likely due to brain enlargement and posterolateral growth of the ala major. After birth, occlusion causes the anterior growth of the mandibular fossa of the squamosa, which moves the ala major away from the TMJ. Similarly, the lateral growth of the sphenoid toward the squamosa suture may also stop in children.

Sex diferences in serum and synovial fluid C-reactive protein concentration in healthy dogs.

Differences between serum C-reactive protein (SCRP) and synovial fluid C-reactive protein (SFCRP) concentrations in healthy animals may be influenced by the sex of the individual and associated with various factors. The objective of this study was to evaluate the disparities in SCRP and SFCRP concentrations between females and males, as well as within each sex. Sixty healthy dogs (N = 60), comprising both sexes, were enrolled in the study. Peripheral blood and knee synovial fluid samples were collected for SCRP and SFCRP analysis, respectively. Serum C-reactive protein (SCRP) and SFCRP concentrations were measured, with mean of 9.61 ± 4.96 mg/L for SCRP and 1.28 ± 3.05 mg/L for SFCRP. Notably, SFCRP concentrations were consistently lower than SCRP concentrations in both sexes. Statistically significant differences were observed between sexes for both SCRP (P = 0.021) and SFCRP (P = 0.007). Further analysis within females revealed statistically significant differences between SCRP and SFCRP concentrations (P = 0.002), whereas in males, such differences were not significant (P = 0.175). Additionally, weak correlations were found between SCRP and SFCRP concentrations for both sexes (females r = 0.07; males r = 0.29). Joint capsule thickness was assessed using ultrasonography, revealing thicker joint capsules in males. A robust positive association was noted between joint capsule thickness and the SFCRP concentration in both sexes. These findings offer valuable insights into the dynamics of CRP in the context of joint health in male and female patients, elucidating the underlying pathological mechanisms of joint disease and inflammation. Overall, this underscores the importance of considering sex-specific factors in the assessment and management of joint health, as well as in the design and interpretation of studies involving SFCRP concentrations.

Association of Range of Motion Deficit and Recurrence of Pain After Treatment of Adhesive Capsulitis.

INTRODUCTION: We evaluated the factors influencing the duration of significant pain reduction after conservative management for adhesive capsulitis (AC). METHODS: Follow-up for 6-8 months was performed with 141 patients with AC who experienced significant pain reduction after treatment. Clinical and demographic factors, numeric rating scale (NRS) scores, and shoulder range of motion (ROM) were collected and assessed pretreatment (T0), at 5 weeks post-treatment (T1), and at 6-8 months post-treatment (T2). Patients were divided into successful (n = 96) and unsuccessful (n = 45) NRS groups according to the degree of pain reduction at T2. We assessed post-treatment NRS and ROM improvement scores within each group and compared these parameters between the two groups. RESULTS: Significant NRS and ROM improvements were achieved in all patients who participated in our study. The unsuccessful NRS group demonstrated a lack of significant improvement in abduction at T1 and T2. All T1 and shoulder ROM measurements among the unsuccessful NRS group were significantly smaller than those among the successful NRS group. CONCLUSIONS: Failure to achieve a significant improvement in abduction angle after conservative management of AC was significantly associated with pain recurrence.

Elbow anatomy in perspective of joint capsule and surrounding aponeuroses: a narrative review.

Background: Because of the proximity of several ligaments, aponeuroses, and capsule in the limited area of the elbow joint, the precise anatomy is difficult to understand. In the current narrative review, we focused on two anatomical perspectives: the capsular attachment and structures consisting of ligaments. Methods: Based on the previously performed studies regarding the elbow anatomy, a narrative review was prepared in terms of the capsular attachment and structures consisting of ligaments. Results: At the tip of the coronoid process, the joint capsule attaches roughly 6 mm distal to its tip with 6-12 mm length. On the lateral epicondyle of the humerus, the capsular attachment at the anterior part of the extensor carpi radialis brevis origin is narrower than the one distal to it. A single interpretation of the lateral collateral ligament is the capsulo-aponeurotic membrane, which is composed of the joint capsule intermingling with the supinator aponeurosis. The anterior bundle of the ulnar collateral ligament could be interpreted as the grossly separated collagenous structure from the tendinous complex, which is composed of the tendinous septum between the flexor digitorum superficialis and pronator teres muscle, the medial part of the brachialis muscle, and deep aponeurosis of the flexor digitorum superficialis muscle. Discussion: Based on these perspectives, ligaments could function as a "static-dynamic" stabilizer rather than a simple static one.

Role of hypoxia-mediated pyroptosis in the development of extending knee joint contracture in rats.

Joint contracture is one of the common diseases clinically, and joint capsule fibrosis is considered to be one of the most important pathological changes of joint contracture. However, the underlying mechanism of joint capsule fibrosis is still controversial. The present study aims to establish an animal model of knee extending joint contracture in rats, and to investigate the role of hypoxia-mediated pyroptosis in the progression of joint contracture using this animal model. 36 male SD rats were selected, 6 of which were not immobilized and were used as control group, while 30 rats were divided into I-1 group (immobilized for 1 week following 7 weeks of free movement), I-2 group (immobilized for 2 weeks following 6 weeks of free movement), I-4 group (immobilized for 4 weeks following 4 weeks of free movement), I-6 group (immobilized for 6 weeks following 2 weeks of free movement) and I-8 group (immobilized for 8 weeks) according to different immobilizing time. The progression of joint contracture was assessed by the measurement of knee joint range of motion, collagen deposition in joint capsule was examined with Masson staining, protein expression levels of HIF-1α, NLRP3, Caspase-1, GSDMD-N, TGF-ß1, α-SMA and p-Smad3 in joint capsule were assessed using western blotting, and the morphological changes of fibroblasts were observed by transmission electron microscopy. The degree of total and arthrogenic contracture progressed from the first week and lasted until the first eight weeks after immobilization. The degree of total and arthrogenic contracture progressed rapidly in the first four weeks after immobilization and then progressed slowly. Masson staining indicated that collagen deposition in joint capsule gradually increased in the first 8 weeks following immobilization. Western blotting analysis showed that the protein levels of HIF-1α continued to increase during the first 8 weeks of immobilization, and the protein levels of pyroptosis-related proteins NLRP3, Caspase-1, GSDMD-N continued to increase in the first 4 weeks after immobilization and then decreased. The protein levels of fibrosis-related proteins TGF-ß1, p-Smad3 and α-SMA continued to increase in the first 8 weeks after immobilization. Transmission electron microscopy showed that 4 weeks of immobilization induced cell membrane rupture and cell contents overflow, which further indicated the activation of pyroptosis. Knee extending joint contracture animal model can be established by external immobilization orthosis in rats, and the activation of hypoxia-mediated pyroptosis may play a stimulating role in the process of joint capsule fibrosis and joint contracture.

Incidence and epidemiology of adhesive capsulitis during the covid-19 pandemic / Incidência e epidemiologia de capsulite adesiva durante a pandemia de covid-19

ABSTRACT Objective: To evaluate a possible increase of adhesive capsulitis incidence during the COVID-19 pandemic. Methods: A total of 1,983 patients with shoulder disorders were retrospectively analyzed regarding gender, age, development of adhesive capsulitis and comorbidities (systemic arterial hypertension, diabetes mellitus, dyslipidemia, hypothyroidism, hyperthyroidism, depression, and anxiety) in two different periods: from March 2019 to February 2020 and from March 2020 to February 2021. Descriptive and quantitative variables were statistically analyzed. The program used for the calculations was SPSS 17.0 for Windows. Results: During the pandemic, there was a 2.41-fold increase (p < 0.001) in cases of adhesive capsulitis (compared to the previous year). Patients with depression and anxiety had a significantly increased risk by 8.8 (p < 0.001) and 14 (p < 0.001) times, respectively, of developing frozen shoulder (regarding the two periods studied). Conclusion: A significant increase in the incidence of frozen shoulder was observed after the onset of the COVID-19 pandemic in addition to a simultaneous increase of psychosomatic disorders. Prospective studies would help to ratify the idea contained in this research. Level of Evidence III, Observational Cross-Sectional Study.

RESUMO Objetivo: Avaliar se houve aumento da incidência de capsulite adesiva durante a pandemia de COVID-19. Métodos: Foram analisados, retrospectivamente, 1.983 pacientes com desordens do ombro quanto a sexo, idade, desenvolvimento de capsulite adesiva e comorbidades (hipertensão arterial sistêmica, diabetes mellitus, dislipidemia, hipo/hipertireoidismo, depressão e ansiedade) em dois períodos distintos: de março de 2019 a fevereiro de 2020 e de março de 2020 a fevereiro de 2021. Procedeu-se à análise estatística das variáveis descritivas e quantitativas, utilizando o software SPSS 17.0 for Windows para os cálculos. Resultados: Durante a pandemia, houve aumento de 2,41 vezes (p < 0,001) de casos de capsulite adesiva em relação ao ano anterior. Considerando os períodos estudados, pacientes com depressão e ansiedade apresentaram um risco significativamente aumentado em 8,8 (p < 0,001) e 14 (p < 0,001) vezes, respectivamente, de desenvolver a patologia em questão. Conclusão: Observou-se um aumento significativo da incidência de ombro congelado após o início da pandemia de COVID-19, além de sua relação com distúrbios psicossomáticos. São necessários estudos prospectivos futuros para ratificar a ideia contida nesta pesquisa. Nível de Evidência III, Estudo Transversal Observacional.

Eminectomía bilateral como tratamiento para luxación crónica de articulación temporomandibular. Reporte de caso / Bilateral eminectomy as a treatment for chronic temporomandibular joint dislocation. Case report

Introducción: la luxación de la articulación temporomandibular es un desplazamiento del cóndilo fuera de sus posiciones funcionales dentro de la fosa articular y la eminencia articular, la cual ocasiona una pérdida completa de la función articular. La luxación crónica es toda luxación aguda que progresa sin un tratamiento específico y que puede ser de carácter recurrente. La eminectomía es un tratamiento quirúrgico definitivo contra la luxación crónica de articulación temporomandibular. Objetivo: reportar el caso clínico de un paciente masculino, de la tercera década de su vida, con diagnóstico de luxación crónica de la articulación temporomandibular de cinco meses de evolución y presentar una revisión actualizada de la literatura sobre este procedimiento quirúrgico. Caso clínico: el paciente fue tratado quirúrgicamente con eminectomía bilateral. Discusión: la eminectomía es un procedimiento quirúrgico controversial; sin embargo, recientes investigaciones lo catalogan como seguro y efectivo. Conclusión: el caso clínico presentado muestra un buen resultado.

Background: Temporo-mandibular joint dislocation is a displacement of the condyle, out of its functional positions within the articular fossa and articular eminence, causing a complete loss of joint function. Chronic dislocation is any acute dislocation that progresses without specific treatment and that can be recurrent. Eminectomy is a definitive surgical treatment for chronic temporomandibular joint dislocation. Objective: To report the clinical case of a male patient in the third decade of his life with a diagnosis of chronic dislocation of the temporomandibular joint of 5 months of evolution and to carry out an updated review of the literature on this surgical procedure. Case Report: The patient was treated surgically with bilateral eminectomy. Discussion: Eminectomy is a controversial surgical procedure; recent research classifies it as safe and effective. Conclusion: The presented clinical case shows a good result.

Treatment of Irreparable Rotator Cuff Tears: Superior Capsular Reconstruction with Fascia Lata Allograft / Tratamento das rupturas irreparáveis do manguito rotador: Reconstrução capsular superior com aloenxerto de fáscia lata

Abstract Objective The objective of the present study was to evaluate the efficacy and safety of superior capsular reconstruction (SCR) using fascia lata allograft. Methods A prospective case series of 15 patients with irreparable supraspinatus tear who underwent SCR using fascia lata allograft. The American Shoulder and Elbow Surgeons (ASES) scale at 12 months after surgery was the primary outcome. The University of California Los Angeles (UCLA), Constant-Murley, and Single Assessment Numeric Evaluation (SANE) scales, in addition to the range of motion, were secondary outcomes. Radiological parameters were also evaluated by simple radiographs and magnetic resonance imaging (MRI). Results Fifteen patients completed 12 months of postoperative follow-up. The ASES score increased from 34.0 to 73.0 (p= 0.005). The UCLA, Constant-Murley, and SANE scales also showed statistically significant differences (p= 0.001; p= 0.005; and p= 0.046). In the evaluation of range of motion, there was improvement in elevation and in external rotation (95 to 140°, p= 0.003; 30 to 60°, p= 0.007). Six patients (40%) had complete graft healing. The clinical outcomes were significantly higher in the patients who presented graft healing. Conclusions Superior capsular reconstruction using a fascia lata allograft is a safe and effective procedure in short follow-up. Level of Evidence IV; Therapeutic Study; Case Series.

Resumo Objetivo O objetivo do presente estudo foi avaliar a eficácia e a segurança da reconstrução capsular superior (RCS) com a utilização do aloenxerto de fáscia lata. Métodos Uma série de casos prospectivos de 15 pacientes com ruptura irreparável do supraespinhal foi submetida a RCS com aloenxerto de fáscia lata, sendo adotada como desfecho primário a escala American Shoulder and Elbow Surgeons (ASES, na sigla em inglês) aos 12 meses do pós-operatório. Como desfechos secundários, foram adotadas as escalas da University of California Los Angeles (UCLA, na sigla em inglês), Constant-Murley, e Single Assessment Numeric Evaluation (SANE, na sigla em inglês), além da amplitude de movimento. Os parâmetros radiológicos também foram avaliados por radiografias simples e ressonância magnética (RM). Resultados Quinze pacientes completaram 12 meses de acompanhamento pós-operatório. O escore ASES aumentou de 34,0 para 73,0 (p= 0,005). As escalas UCLA, Constant-Murley e SANE também apresentaram diferenças estatisticamente significativas (p= 0,001; p= 0,005; e p= 0,046). Na avaliação da amplitude de movimento, houve melhora na elevação e rotação externa (95 a 140°, p= 0,003; 30 a 60°, p= 0,007). Seis pacientes (40%) tiveram cicatrização completa do enxerto. Os desfechos clínicos foram significativamente maiores nos pacientes que apresentaram cicatrização do enxerto. Conclusões A RCS com aloenxerto de fáscia lata é um procedimento seguro e eficaz com um curto acompanhamento de tempo. Nível de evidência IV; Estudo Terapêutico; Série de casos.