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Osteoarthritis is a common cause of morbidity and mortality in geriatric gazelles. Propionibacterium australiense has been reported as a cause of systemic granulomas in cattle, but there are no descriptions of this bacteria infecting other species nor causing osteoarthritis, to our knowledge. An 8-y-old, castrated male, sand gazelle (Gazella leptoceros leptoceros) was managed for chronic, intermittent, progressive osteoarthritis of the right tarsus. Serial biopsies revealed pyogranulomatous dermatitis with intralesional bacteria. Serial diagnostic imaging identified osseous and soft tissue proliferation with draining tracts. Treatments over 1 y included broad-spectrum antibiotics, anti-inflammatories, joint debridement, and infusion with platelet-rich plasma and stem cells. Despite therapy, lameness persisted, azotemia developed, and subsequently, the animal was euthanized. On postmortem examination, the periarticular tissue of the right tarsus was markedly expanded by pyogranulomas and fibrosis. Histologically, the synovium, joint capsule, and overlying soft tissues were markedly expanded by pyogranulomas and numerous gram-positive and acid-fast–negative filamentous bacteria surrounded by Splendore–Hoeppli material. Within the joint, there was regionally extensive cartilage ulceration, osteonecrosis, osteolysis, and pannus formation. PCR assay of affected formalin-fixed, paraffin-embedded tissue amplified segments of 16S rRNA and β subunit of bacterial RNA polymerase (rpoB) genes with 99.7% and 95.6% identity to P. australiense. This bacterium should be considered a differential for chronic pyogranulomatous osteoarthritis in gazelles. [ABSTRACT FROM AUTHOR]

Synovial myxoma, a rare joint tumor in dogs, has traditionally been considered benign, acknowledging that local invasion into regional tissues including bone may be present. Given the diagnostic challenges in distinguishing synovial myxoma from other joint lesions through clinical features and diagnostic imaging, definitive diagnosis relies on characteristic gross and histologic features. Within the inner surface of the joint capsule, synovial myxomas form nodules of stellate-to-spindle cells within abundant myxomatous matrix. We present here 2 cases of synovial myxoma with metastasis to regional lymph nodes and compare these 2 cases to 3 cases without evidence of lymph node metastasis. Aside from lymphovascular invasion in one case with metastasis, there were no overt histologic features of the primary tumor to suggest aggressive biologic behavior. The finding of lymph node metastasis warrants reconsideration of the term "synovial myxoma" for this neoplasm. We suggest the term "synovial myxosarcoma," considering that histologic features of the primary tumor do not predict biologic behavior. Our case series highlights the importance of lymph node sampling in suspected synovial myxosarcoma cases as well as thorough histologic examination, emphasizing careful evaluation for lymphovascular invasion. [ABSTRACT FROM AUTHOR]

This article discusses the prevalence and significance of osteochondral fragmentation (OCF) in the palmar/plantar proximal interphalangeal (PIP) joint of yearling Thoroughbred horses. The study highlights the importance of comprehensive lameness examinations, including diagnostic analgesia, radiography, and ultrasonography, in assessing the risk and impact of OCF on future athletic performance. The article suggests that ultrasound examination of associated soft tissues, in addition to radiography, may be necessary to accurately evaluate the significance of OCF. The authors also emphasize the need for further research to better understand the management and treatment options for horses with OCF in the PIP joint. [Extracted from the article]

Introduction: Psoriasis is a widespread chronic inflammatory skin disease; enthesitis is inflammation of the tendon, ligament, and joint capsule insertion, prevalent in patients with psoriatic arthritis. Objectives: The aim of the study to evaluate the utility of the Madrid Sonography Enthesitis Index scoring system for accurate detection of subclinical enthesitis in patients with Psoriasis compared with healthy controls. Another objective was to assess increase in enthesis area and Psoriatic arthritis incidence, in a prospective 1-year follow-up. Method: Patients aged ≥18 years who were diagnosed with Psoriasis, without musculoskeletal complaints, and who did not have any clinical sign and/or symptom of enthesitis and synovitis were included in the study. The patients and healthy controls were evaluated with ultrasonography. Ultrasonography evaluation consisted of the detection of gray-scale enthesitis and power Doppler signal in the enthesis areas. The Madrid Sonography Enthesitis Index scoring system was used to quantify the extent of the sonographic enthesis abnormalities. Results: The mean MASEI score, structure, thickness, erosion, and calcification were significantly higher in the Psoriasis group than in the control group. The mean MASEI score, structure, erosion, and calcification measurements were significantly higher at the last examination when compared to the first examination. The triceps was the most commonly affected tendon in both groups. Conclusion: Ultrasonography is an important tool for diagnosis and follow-up of subclinical enthesitis in patients with psoriasis. Regardless of disease duration and severity, patients should be screened using ultrasonography at yearly intervals. [ABSTRACT FROM AUTHOR]

A 12 yr old male castrated miniature Australian shepherd dog presented for surgical consultation of historical bilateral medial patellar luxations with a 3 mo history of an acute onset of a left pelvic limb lameness. Physical examination confirmed medial patellar luxations and a mass effect of the left stifle medially. Radiographs showed medial distension of the joint capsule by a soft tissue opacity. Fine-needle aspirate of the left stifle revealed a mesenchymal cell population. Left medial parapatellar stifle arthrotomy found a fatty mass, which was excised at its base. A benign fibrolipoma was diagnosed on histopathology, and the excision was expected to be curative. The owners reported immediate improvement of perceived comfort postoperatively. At 2 and 24 wk, the dog returned to a normal level of function. Lipomas of the stifle, although rare, should be considered as a differential for intra-articular masses causing lameness. [ABSTRACT FROM AUTHOR]

This article, titled "Where are the broken needle fragments? Are they intra-articular or not? Case report," discusses a rare case of foreign body penetration in a child's knee. The authors present a case where two foreign bodies were detected in the knee and removed through arthroscopic intervention. The article emphasizes the importance of multidimensional thinking and detailed examination when dealing with a limping child, and suggests that diagnostic arthroscopy is a safe and minimally invasive procedure for cases where the location of foreign bodies cannot be fully determined. The authors hope that presenting this case will aid in the differential diagnosis and treatment of similar cases. [Extracted from the article]

Background: Ultrasound (US) guided intra‐articular elbow injections are commonly performed in clinical practice. Objective: To describe a proximal to distal approach for US‐guided intra‐articular elbow injection. Design: Cadaveric study. Settings: Academic institution. Methods: Both elbows of a single cadaver were injected with green‐colored water‐diluted latex dye using the US‐guided proximal to distal approach. In the left elbow, the needle was kept in situ; in the right elbow, the needle was removed. Subsequently, a layer‐by‐layer anatomical dissection was performed in both elbows. Main Outcome Measures: Presence and distribution of the latex dye and location of the needle tip within the elbow joint capsule. Results: Anatomical dissection of both elbows confirmed the correct intra‐articular position of the needle tip in the left elbow as well as correct placement of the latex dye bilaterally. During layer‐by‐layer dissection of the left elbow, the position of the radial nerve was observed anterior to the needle. Conclusions: This cadaveric observation demonstrated that the US‐guided proximal to distal approach is a convenient technique to access the elbow joint. Compared to the previously described techniques, the in‐plane, proximal to distal approach may provide excellent needle visibility during the entire procedure, precisely targeting the articular space. The preliminary data need to be validated in additional clinical studies. [ABSTRACT FROM AUTHOR]

Background: Ultrasound (US)‐guided intraarticular hip joint injections are commonly performed using an in‐plane anterior approach, which has several limitations. Objective: To describe and report a "lateral" (lateral to medial) approach for US‐guided intraarticular hip injection. Design: Cadaveric investigation. Setting: Academic institution, department of anatomy. Participants: One cadaveric specimen. Methods: Both hips of a single cadaver were injected using the US‐guided lateral approach. In the left hip, the needle was inserted and kept in situ. The right hip was injected with white‐colored water‐diluted latex dye. Subsequently, a layer‐by‐layer anatomical dissection was performed. Main Outcome Measures: Presence and distribution of latex dye and location of needle tip within the joint capsule of the hip. Results: Anatomical dissection of the left and right hips confirmed the correct intraarticular position of the needle tip and the placement of the latex dye, respectively. During layer‐by‐layer dissection of the left hip, positions of the lateral cutaneous nerve and the lateral circumflex femoral artery were observed anterior to the needle, 30 mm for the nerve and 8 mm for the artery. Conclusions: This preliminary study demonstrated that the US‐guided lateral approach is a convenient technique to access the hip joint in a cadaveric specimen. Compared with the "classical" anterior technique, the lateral approach may provide several advantages, including improved needle visibility, theoretically decreased risk of vascular injury, and less risk of needle contamination. Because injury to the lateral epiphyseal arteries is possible when lateral approach is used, caution is required, especially in children. These preliminary conclusions will need to be validated in future/larger clinical studies. [ABSTRACT FROM AUTHOR]

A 4 yr old female neutered Labrador retriever was referred with a history of left hind-limb lameness and an acute, nonpainful, subcutaneous mass on the medial aspect of the left stifle. Stifle radiographs and fine needle aspirates of the soft tissue mass performed by the referring veterinarian confirmed the presence of predominantly highly granulated mast cells, consistent with a mast cell tumor. Computed tomography demonstrated a soft tissue mass centered on the left medial stifle, with associated joint effusion and polyostotic lytic lesions on the tibial plateau and distal patella. Ultrasound-guided aspirates of the liver, spleen, and popliteal lymph nodes were obtained to rule out further metastatic spread. Cytology of the joint fluid demonstrated a low number of well-differentiated mast cells. Surgical and oncological interventions were discussed, and full hind-limb amputation was elected. Histopathological analysis of the submitted tissues after amputation diagnosed a subcutaneous mast cell tumor with neoplastic cell infiltrate extending into sections of joint capsule and synovial membrane. Infiltration to the tibia and distal patella were suspected following the presence of mast cell clusters in both osteolytic lesions. No evidence of metastasis was identified in the popliteal lymph node. Postoperative monitoring of iliac lymph node size using ultrasound did not identify evidence of metastasis 12 mo postoperatively. [ABSTRACT FROM AUTHOR]

Joint immobilization is frequently administered after fractures and ligament injuries and can cause joint contracture as a side effect. The structures responsible for immobilization-induced joint contracture can be roughly divided into muscular and articular. During remobilization, although myogenic contracture recovers spontaneously, arthrogenic contracture is irreversible or deteriorates further. Immediately after remobilization, an inflammatory response is observed, characterized by joint swelling, deposit formation in the joint space, edema, inflammatory cell infiltration, and the upregulation of genes encoding proinflammatory cytokines in the joint capsule. Subsequently, fibrosis in the joint capsule develops, in parallel with progressing arthrogenic contracture. The triggers of remobilization-induced joint inflammation are not fully understood, but two potential mechanisms are proposed: 1) micro-damage induced by mechanical stress in the joint capsule, and 2) nitric oxide (NO) production via NO synthase 2. Some interventions can modulate remobilization-induced inflammatory and subsequent fibrotic reactions. Antiinflammatory treatments, such as steroidal anti-inflammatory drugs and low-level laser therapy, can attenuate joint capsule fibrosis and the progression of arthrogenic contracture in remobilized joints. Antiproliferative treatment using the cellproliferation inhibitor mitomycin C can also attenuate joint capsule fibrosis by inhibiting fibroblast proliferation without suppressing inflammation. Conversely, aggressive exercise during the early remobilization phases is counterproductive, because it facilitates inflammatory and then fibrotic reactions in the joint. However, the adverse effects of aggressive exercise on remobilization-induced inflammation and fibrosis are offset by anti-inflammatory treatment. To prevent the progression of arthrogenic contracture during remobilization, therefore, care should be taken to control inflammatory and fibrotic reactions in the joints. [ABSTRACT FROM AUTHOR]

Therapeutic approaches to treat joint contracture after anterior cruciate ligament (ACL) reconstruction have not been established. Arthrofibrosis accompanied by joint inflammation following ACL reconstruction is a major cause of arthrogenic contracture. In this study, we examined whether antiinflammatory treatment using low-level laser therapy (LLLT) can prevent ACL reconstruction-induced arthrogenic contracture. Rats underwent ACL transection and reconstruction surgery in their right knees. Unoperated left knees were used as controls. After surgery, rats were reared with or without daily LLLT (wavelength: 830 nm; power output: 150 mW; power density: 5 W/cm2; for 120 s/day). We assessed the passive extension range of motion (ROM) after myotomy at one and two weeks post-surgery; the reduction in ROM represents the severity of arthrogenic contracture. ROM was markedly decreased by ACL reconstruction at both time points; however, LLLT partially attenuated the decrease in ROM. One week after ACL reconstruction, the gene expression of the proinflammatory cytokine interleukin-1ß in the joint capsule was significantly upregulated, and this upregulation was significantly attenuated by LLLT. Fibrotic changes in the joint capsule, including upregulation of collagen type I and III genes, shortening of the synovium, and thickening were caused by ACL reconstruction and seen at both time points. LLLT attenuated these fibrotic changes as well. Our results indicate that LLLT after ACL reconstruction could attenuate the formation of arthrogenic contracture through inhibition of inflammation and fibrosis in the joint capsule. Thus, LLLT may become a novel therapeutic approach for ACL reconstructioninduced joint contracture. [ABSTRACT FROM AUTHOR]

To evaluate the effects of diabetes and corticosteroid injected in the joints on the shoulder motion, gait, and joint capsular properties in a rat stiffness model. A total of 27 rats were randomly distributed into 3 groups—nondiabetes group (group A), diabetes group (group B), and diabetes plus steroid injection group (group C). The diabetes model was developed by inducing hyperglycemia with a submaximal dose of streptozotocin and the stiffness model by completely immobilizing the right shoulder of each animal in all groups with sutures passed between the scapula and humeral shaft. The left shoulder was used as an untreated control in all groups. Three weeks after immobilization, the sutures were removed in all groups, and a single dose of triamcinolone acetonide (0.5 mg/kg) was injected into the glenohumeral joint in group C. After 3 weeks of free activity, range of motion (ROM) evaluation, gait analysis by stride length, and capsular area measurement were performed in all rats. Hyperglycemia was successfully induced with a mean blood glucose level of 448.9±55.9 mg/dL in group B and 431.6±17.8 mg/dL in group C, which were significantly higher than 136.5±13.4 mg/dL in group A (P <.001). A significantly smaller ROM and stride length were found in the right (stiffness-induced) shoulder than that in the left (control) shoulder only in group B, and significantly larger capsular area in the right shoulder than that in the left shoulder in groups A and B (all P <.05). However, in group C, there were no differences between the right and left shoulders in all measurements (all P >.05). In case of the right shoulders in each group, group C showed significantly larger ROM (68° ± 11° vs. 42° ± 7°) and smaller capsular area (3934.4 ± 537.1 pixels vs. 7402.3 ± 1840.3 pixels) than group B (all P <.0167). The diabetic model had a detrimental effect on the development of stiffness by thickening the joint capsule, and an intra-articular steroid injection resolved the thickened joint capsule and restored shoulder motion. [ABSTRACT FROM AUTHOR]

Anterior displacement of the temporomandibular joint (TMJ) disc is the most typical pathological condition of TMJ disorders. Structures attached to the articular disc may support the disc in various directions and contribute to stabilizing the TMJ. However, the relationship between the articular disc, capsule, and masticatory muscles remains unclear. Therefore, this study aimed to clarify the relationship between the masticatory muscles, related masticatory fascia, articular disc, and capsule. We examined 10 halves from adult Japanese cadavers, with five halves macroscopically analyzed and the remaining five histologically analyzed. The TMJ was dissected from the lateral aspect for gross anatomical analysis. For histological analysis, the relationship between the temporal and masseteric fasciae and the articular capsule was observed in the coronal section. Additionally, we evaluated relationships among the disc, capsule, temporal fascia, and masseteric fascia in 10 living and healthy volunteers using magnetic resonance imaging. The articular disc was attached to the capsule without a clear border. The capsule continued into the masseteric and temporal fasciae. Consequently, the articular disc, capsule, masseteric, and temporal fasciae were considered a single complex. The single complex of the temporalis, masseter, capsule, masticatory fascia, and disc may antagonize the force in the posterolateral direction through the fascia. [ABSTRACT FROM AUTHOR]

The marginal transitional zone (MTZ) is peripherally located within the diarthrodial joint, and represents the junction of synovium, fibrous joint capsule, articular cartilage, periosteum, and bone. The purpose of this study is to characterize age-related differences in protein expression of matrix and molecular regulators in the marginal transitional zone of neonatal and weanling foals. Several families of proteins with known roles in cartilage and bone development are investigated, including matrix molecules, members of the Wnt signaling family, apoptotic factors and paracrine cell signaling molecules. Our results demonstrate differential protein expression in the marginal transitional zone from the lateral femoral trochlear ridge of neonatal and weanling foals. Protein expression of several paracrine signaling molecules (Ihh, PTHrP, PDGF, VEGF, β-catenin, cytochrome C) within MTZ cartilage is higher in weanling-aged foals. Collagen type II and lubricin expression is similarly greater in weanling-aged foals, while matrix metalloproteinases are lower, likely reflecting the remodeling that occurs during cartilage development as increasing forces are placed on cartilage. • Paracrine signaling is greater in MTZ cartilage of weanling-aged foals. • Collagen II and lubricin higher in weanling MTZ cartilage Separate bullet point- Matrix metalloproteinases higher in neonate MTZ. [ABSTRACT FROM AUTHOR]

A thickened joint capsule is believed to be one of the most specific manifestations of and the primary restraint against range of motion (ROM) in frozen shoulders. The purpose of this study was to evaluate the relationship among ROMs under general anesthesia before surgery and the effects of each joint capsular release on ROM. ROM was measured using a goniometer with scapular fixation. Arthroscopic pan-capsular release was performed with the patient in the beach-chair position in the following order: (1) rotator interval, (2) coracohumeral ligament, (3) superior capsule, (4) middle glenohumeral ligament, (5) anterior inferior glenohumeral ligament, and (6) posterior inferior glenohumeral ligament. ROMs in forward flexion (FF), lateral elevation (LE), external rotation with the arm at the side (ER1), external rotation at 90° of LE (ER2), internal rotation at 90° of LE (IR2), horizontal flexion, external rotation at 90° of FF (ER3), and internal rotation at 90° of FF (IR3) were evaluated before and after each release. A total of 32 consecutive shoulders were included. After each capsular release, the ROM recovered; the final ROM was significantly greater on the affected side than on the unaffected side. Significant correlations were found between FF and LE, FF and ER1, ER1 and ER2, ER1 and ER3, ER2 and ER3, and IR2 and IR3 on both sides, regardless of surgery. Each segment of the joint capsule affected ROM in all directions, supporting the need for whole-joint capsular release; ROM was significantly greater on the affected side than on the unaffected side after surgery. [ABSTRACT FROM AUTHOR]

To date, we could find no study concerning the relationship between mechanoreceptors in the joint capsule of the first metatarsophalangeal joint and hallux valgus deformity. We aimed to investigate the presence of mechanoreceptors in samples obtained from the first metatarsophalangeal joint capsules of patients with hallux valgus deformity to improve our understanding of the clinical and histopathological features of the disease. Samples were taken from the first metatarsophalangeal joint capsules of 13 fresh-frozen cadavers with normal anatomy (controls) and 29 patients undergoing surgery for hallux valgus (cases). For light microscopy, excised specimens were fixed in 10% formaldehyde and processed for routine histopathological investigation. All samples were dehydrated in a series of ethanol, cleared in xylene, and embedded in paraffin. Orientation of collagen fibers was determined on Masson's trichrome–stained sections, and mechanoreceptors were evaluated on S-100-immunostained sections. In the sections stained with Masson's trichrome, the orientation of collagen fibers was regular in the control group. However, coarse and disoriented collagen bundles were observed in the hallux valgus cases (P ≤.05). S-100 immunostaining was positive in the sections of both the cases and controls. Finally, free nerve endings were more abundant in the samples obtained from the capsules of hallux valgus cases than from the control group (P ≤.05). An increase in the number of free nerve endings within the capsules of the first metatarsophalangeal joints in feet with hallux valgus deformity might have a role in the development of clinically relevant joint pain and instability. [ABSTRACT FROM AUTHOR]

Background The etiology of frozen shoulder (FS) is unclear. Accordingly, this study used a label-free quantitative shotgun proteomic approach to elucidate the pathogenesis of FS based on protein expression levels. Methods Tissue samples from the rotator interval (RI), middle glenohumeral ligament (MGHL), and anterior-inferior glenohumeral ligament (IGHL) were collected from 12 FSs with severe stiffness and 7 shoulders with a rotator cuff tear (RCT) as controls. Protein mixtures were digested and analyzed by nano-liquid chromatography/electrospray ionization–tandem mass spectrometry. Relative protein expression levels were calculated by the signal intensity of identified peptide ions on mass spectra. Differentially expressed proteins between FS and RCT samples were evaluated by a gene enrichment analysis using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes. Results We identified 1594 proteins, 1358 of which were expressed in all 6 tissue groups. We detected more upregulated proteins in the upper (RI and MGHL) FS groups and the lower (IGHL) RCT group than in the comparative groups, respectively. Various proteins with functions in tissue repair, collagen metabolism and fibrillation, cell–cell and cell–matrix adhesion, blood coagulation, and the immune response were expressed more highly in the RI and MGHL FS groups than in the RCT group. Proteins with functions in phagocytosis, glutathione metabolism, retinoid metabolism, and cholesterol metabolism were expressed more highly in the IGHL RCT group than in the FS group. Conclusions The pathophysiology of FS differs between the upper and lower parts of the joint capsule. Different treatment strategies for FS may be appropriate, depending on the location. [ABSTRACT FROM AUTHOR]

Ligamentum Mucosum(LM) is a ligamentous structure within the synovial layer of the knee joint capsule. For a long time LM was perceived as the vestigial remnant from the embryological development of the knee. Being treated as an irrelevant structure LM was often the first victim of shaver during arthroscopy. However, last years have shown increased interest in this structure due to its potentially significant clinical role. Our aim was to classify LM based on its morphological characteristics and examine its microanatomy using immunohistochemical analysis to reveal the potential clinical value for surgeons. We have examined sixteen fresh frozen lower limbs, 6 females (mean age 83.1 ± 3.4 years) and 10 males (mean age 84.2 ± 6.8 years). Classical histological H+E stain was routinely conducted. Subsequently, CD31 antibody (DAKO, Monoclonal Mouse Anti-Human, Clone JC70A) was used to mark vascular epithelium. Monoclonal Mouse Anti-Human Neurofilament Protein (NFP) antibody (DAKO, Clone 2F11) was used to expose the nerves. Moreover, we have conducted arthroscopic visualizing and suturing LM to the torn ACL during routinely performed arthroscopic suturing of the ACL. The dissection process has revealed that LM was present only in 75% of cases. Histological examination confirmed the presence of longitudinal collagen fiber bundles in all samples. Tiny nerves were confirmed by NFP, along the subsynovial layer in all samples. CD-31 immunostain revealed the presence of many vascular vessels along the entire ligament, especially well developed at its distal end. Our study has revealed that LM contains rich vascular network. Thus, it may be a donor for the revascularization process after ACL tear or reconstruction which may improve the recovery. Another great advantage of the LM is the presence of nerves along the subsynovial layer, hopefully they may serve as the source of reinnervation and hence better clinical outcome. Based on our results we believe that seemingly irrelevant LM may be very useful during surgical procedures in the knee region. Suturing LM to the ACL may not only prevent the infrapatellar fat pad from subluxation but also improve the blood flow and reinnervation of the injured ACL. Until now there are only a few studies examining microanatomy of the LM. This basic knowledge may serve as the foundation for surgical procedures. Hopefully our findings may be useful for surgeons while planning surgical procedures or clinicians while diagnosing patients who suffer anterior knee pain. [ABSTRACT FROM AUTHOR]

This study aims to explore the mechanism of miR-211–5p in extracellular vesicles (EVs) derived from bone marrow mesenchymal stem cells (BMSCs) in improving frozen shoulder (FS) in rat models. Rat BMSCs and EVs derived from rat BMSCs were isolated, identified, and then injected into rats to assess the expression of TGF-β, MMP1, MMP3, MMP12, GAP43, and PGP9.5 in shoulder capsule tissues. The range of motion of bilateral glenohumeral joints was assessed and pathological changes of shoulder capsule tissues were observed after hematoxylin-eosin staining. The binding sites of miR-211–5p to KDM2B and LACC1 to H3K4me3 were measured. FS rat models with LACC1 highly expressed were established to assess the motion of bilateral glenohumeral joints and expression of arthritis related factors in rats. EVs were successfully extracted from BMSCs. Injection of BMSCs-EVs could improve the activity of bilateral glenohumeral joints and the pathological condition of joint capsule in rats. Elevated expression of miR-211–5p was found in rats injected with BMSCs-EVs. Dual luciferase assay showed that miR-211–5p had a binding site with KDM2B. ChIP, qRT-PCR, and western blot experiments showed BMSCs-EVs injection resulted in elevated enrichment of LACC1 promoter in shoulder capsule tissues of FS rats, and decreased mRNA and protein expression of KDM2B and increased H3K4me3 methylation. Overexpression of LACC1 could also improve the pathological condition of joint capsule tissue. miR-211–5p in EVs derived from BMSCs increased H3K4me3 methylation in shoulder capsule tissue of rats by binding KDM2B, resulting in up-regulated transcription level of LACC1 and improving FS. The datasets used or analyzed during the current study are available from the corresponding author on reasonable request. • miR-211–5p in BMSCs-EVs facilitates the repair of rat FS. • miR-211–5p targets KDM2B. • miR-211–5p in BMSCs-EVs reduces the expression of KDM2B in FS rats. • miR-211–5p in BMSCs-EVs increases the expression of LACC1 in FS rats. • Overexpressed LACC1 improves the repair of rat FS. [ABSTRACT FROM AUTHOR]

Background The attachment of the anterior joint capsule on the ulnar coronoid process is not yet completely understood. The purpose of this study was to clarify the anatomic relationship between the anterior capsule of the elbow joint and the tip of the coronoid process. Methods Seventeen embalmed elbows were used for this anatomic study. The anterior capsule of the elbow joint was reflected, and the attachment of the capsule on the coronoid process was exposed. The attachment of the joint capsule on the coronoid process was macroscopically and histologically observed, its relationship to the coronoid tip was assessed, and the length of the attachment of the joint capsule was measured. Results The length of the capsule attachment at the radial side of the coronoid (11.9 mm) was greater than that at the ulnar side (6.1 mm). The bone thickness on the coronoid tip from the proximal edge of the joint capsule attachment was 1.9 mm; together, the cartilage and bone thickness was 4.7 mm. At the radial side of the coronoid, the thickness of the joint capsule at the proximal aspect of the attachment of 2 samples was 0.6 mm and 0.3 mm, and that at the tip of the coronoid was 2.6 mm and 1.7 mm, respectively. Conclusions The anterior capsule of the elbow joint had a substantial attachment on the radial side of the coronoid process. The subtype 2 tip fractures of the O'Driscoll classification included the joint capsule attachment, joint cartilage, and subchondral bone. [ABSTRACT FROM AUTHOR]

The ligamentum mucosum is a ligamentous structure within the synovial layer of the knee joint capsule. It usually arises from the infrapatellar fat pad and is inserted into the intercondylar notch of the femur. In recent years, more attention has been paid to this structure because of its clinical significance. Despite the growing attention, the complex morphology of the ligamentum mucosum has led to many misunderstandings among the scientists and clinicians. Therefore, the main objective of this study was to characterize the morphology of the ligamentum mucosum and its attachment points, classify it, and evaluate its prevalence. Classical anatomical dissection was performed on 70 lower limbs of human fetuses fixed in 10% formalin solution. Morphology was carefully assessed, and morphometric measurements were performed. The types revealed were classified. The ligamentum mucosum was present in 100% of all 70 specimens examined. Two types were detected. Type I (65.71%) - "cord-like". This type was the most common and is characterized by a single longitudinal ligament. The proximal attachment of the ligamentum mucosum was located in the middle of the infrapatellar fat, and the distal attachment was at the tip of the intercondylar notch. Type II (34.29%) - "vertical septum". This type is less common, but its morphology is much more complex compared to type I. It is wider and thicker than type I. Proximally, it is attached to the infrapatellar fat pad and distally through the entire intercondylar notch down to the anterior surface of the anterior cruciate ligament. It divides the joint cavity into medial and lateral sides. The ligamentum mucosum exhibits high morphologic variability, and the view that it is a vestigial remnant of the embryologic development of the knee should be reconsidered. We have proposed an anatomical classification of its types in human fetuses, which is a valuable addition to existing knowledge and will hopefully change the approach of clinicians and scientists. [ABSTRACT FROM AUTHOR]

We examined the time-dependent differences in the effects of treadmill exercise on joint contracture after anterior cruciate ligament (ACL) reconstruction. Rats received ACL reconstructive surgery. After surgery, rats were reared with or without treadmill exercise (60 min/day) starting at 3 days (when inflammatory reactions are active) or 14 days (when inflammatory reactions have subsided) post-surgery. Untreated rats were used as controls. Data were collected at two or four weeks post-surgery. The range of motion (ROM) decreased following surgery at both time points and treadmill exercise during the first two weeks post-surgery further decreased the ROM. Moreover, treadmill exercise during first two weeks post-surgery upregulated the pro-inflammatory cytokine interleukin-1β gene in the joint capsule and aggravated joint capsule fibrosis. For exercise started at 14 days post-surgery, the ROM recovered to control levels at four weeks post-surgery. In addition, delayed exercise contributed to resolving inflammatory and fibrotic reactions. Treadmill exercise initiated soon after surgery aggravates joint contracture via enhanced inflammatory and fibrotic reactions in the joint capsule. Conversely, exercise initiated after active inflammation has subsided facilitates joint capsule reorganization and increases joint ROM. Therefore, aggressive exercise should be started only after active inflammation is resolved to improve joint contracture following ACL reconstruction. • The effects of exercise after ACL reconstruction on contracture are controversial. • Treadmill exercise soon after surgery enhanced inflammatory and fibrotic reactions. • Treadmill exercise soon after surgery aggravated joint contracture. • Exercise after inflammation has subsided facilitated capsule reorganization. • Exercise after inflammation has subsided improved joint contracture. [ABSTRACT FROM AUTHOR]

The Andrew J. Weiland Medal is presented by the American Society for Surgery of the Hand to a midcareer researcher who is dedicated to advancing patient care in the field of hand surgery. This essay, awarded the Weiland Medal in 2012, focuses on posttraumatic elbow joint contractures. Joint contractures are well known to hand surgeons because they limit function of our patients. There is a thorough understanding of the pathoanatomy underlying joint contractures. However, the mechanisms leading to the pathoanatomy are either unknown or partially understood, depending on the etiology of the particular clinical condition. This review describes our research over the past 14 years on posttraumatic elbow joint contractures. It defines pathologic cellular, matrix, and growth factor changes in the joint capsule, elaborates on the development of an animal model of posttraumatic joint contractures, presents an evaluation of a potential prevention strategy based on our research, and outlines future plans to bring this work to the clinical realm for the benefit of patients. [Copyright &y& Elsevier]

Abstract: Detection of ceramic particles in synovial fluids allows early diagnosis of ceramic damage, but there is no evidence of a relationship between ceramic debris in the articular space and in the joint capsule. The aim of the present study is to verify if the particles isolated in the synovial fluid are comparable with those stored in the capsular tissue. Twenty-one patients were enrolled. Both synovial fluid and capsular samples were collected during revision surgery and ceramic particles were isolated and analyzed by scanning electron microscopy and energy-dispersive X-ray microanalysis. It resulted a significant correlation between the samples couples (18 out of 21). This study confirms that the synovial fluid analysis can give a clear definition of the presence of particles in the joint capsule. [Copyright &y& Elsevier]

Background: Frozen shoulder is a debilitating condition characterized by gradual loss of glenohumeral motion with chronic inflammation and capsular fibrosis. Yet its pathogenesis remains largely unknown. We hypothesized that the subacromial bursa may be responsible for the pathogenesis of frozen shoulder by producing inflammatory cytokines. Materials and methods: We obtained joint capsules and subacromial bursae from 14 patients with idiopathic frozen shoulder and from 7 control subjects to determine the expression levels of interleukin (IL) 1α, IL-1β, IL-6, tumor necrosis factor α (TNF-α), cyclooxygenase (COX) 1, and COX-2 by real-time reverse transcriptase–polymerase chain reaction, immunohistochemistry, and enzyme-linked immunosorbent assay. Results: IL-1α, IL-1β, TNF-α, COX-1, and COX-2 were expressed at significantly high levels in the joint capsules of the frozen shoulder group compared with those of the control group. Intriguingly, IL-1α, TNF-α, and COX-2 were also expressed at significantly high levels in the subacromial bursae of the frozen shoulder group compared with those of the control group. Immunohistochemical analysis showed increased expression of COX-2 in both the joint capsules and subacromial bursae of the frozen shoulder group. Conclusions: These findings imply that elevated levels of inflammatory cytokines in the subacromial bursa may be associated with the pathogenesis of inflammation evolving into fibrosis. [Copyright &y& Elsevier]

Abstract: Posterior ankle arthroscopy has traditionally been associated with concern for injury to the posterior tibial nerve and vessels, and this concern is greatest when the patient is positioned supine. Positioning the patient prone could be a safer method for posterior ankle arthroscopy. The purpose of this cadaver study was to determine the anatomic safe zone devoid of vital structures relative to the posteromedial and posterolateral arthroscopic portals created. In addition, exposure of the posterior ankle was evaluated by direct visualization and fluoroscopy to determine the relative utility of these portals. Based on our findings, which are consistent with other previously reported results, we believe that a wide range of ankle pathology can be suited to treatment by means of posterior arthroscopy with the patient in the prone position. [Copyright &y& Elsevier]

Summary: Objective: To investigate the effect of glucosamine on the loss of newly synthesized radiolabeled large and small proteoglycans by bovine tendon, ligament and joint capsule. Design: The kinetics of loss of 35S-labeled large and small proteoglycans from explant cultures of tendon, ligament and joint capsule treated with 10mM glucosamine was investigated over a 10-day culture period. The kinetics of loss of 35S-labeled small proteoglycans and the formation of free [35S]sulfate were determined for the last 10 days of a 15-day culture period. The proteoglycan core proteins were analyzed by gel electrophoresis followed by fluorography. The metabolism of tendon, ligament and joint capsule explants exposed to 10mM glucosamine was evaluated by incorporation of [3H]serine and [35S]sulfate into protein and glycosaminoglycans, respectively. Results: Glucosamine at 10mM stimulated the loss of small proteoglycans from ligament explant cultures. This was due to the increased loss of both macromolecular and free [35S]sulfate to the medium indicating that glucosamine affected the release of small proteoglycans as well as their intracellular degradation. The degradation pattern of small proteoglycans in ligament was not affected by glucosamine. In contrast, glucosamine did not have an effect on the loss of large or small proteoglycans from tendon and joint capsule or large proteoglycans from ligament explant cultures. The metabolism of cells in tendon, ligament and joint capsule was not impaired by the presence of 10mM glucosamine. Conclusions: Glucosamine stimulated the loss of small proteoglycans from ligament but did not have an effect on small proteoglycan catabolism in joint capsule and tendon or large proteoglycan catabolism in ligament, tendon or synovial capsule. The consequences of glucosamine therapy at clinically relevant concentrations on proteoglycan catabolism in joint fibrous connective tissues need to be further assessed in an animal model. [Copyright &y& Elsevier]

Purpose: The purpose of this study was to evaluate the histologic morphology of human shoulder joint capsule after thermal capsulorrhaphy with monopolar radiofrequency energy (mRFE) during short- to long-term follow-up. Methods: This study comprised 27 patients who received an arthroscopic mRFE thermal capsulorrhaphy and 10 patients without mRFE treatment serving as the control group. Biopsy samples from 3 locations (anterior-superior, anterior-inferior, and posterior-medial) of the shoulder joint capsule were harvested from both the mRFE-treated patients and the control patients. The follow-up time for the mRFE treatment ranged from 3.5 to 62 months, which was divided into 3 groups: short, 3.5 to 12 months; medium, 14 to 25 months; and long, 31 to 62 months. The biopsy samples were analyzed via a histologic scoring system, evaluating an intact synovial layer, subsynovial edema, collagen morphology, cellularity, vascularity, and inflammatory cells. Histologic scores among each follow-up group were compared with each other and with those in the control group. Results: There were no significant differences in the histologic categories of intact synovial layer, subsynovial edema, collagen morphology, and inflammatory cells among the control and mid- and long-term mRFE groups. The short-term mRFE group had greater increased cellularity and vascularity compared with the mid- and long-term groups, which progressively improved toward the appearance in the normal control group with time. Conclusions: After mRFE capsulorrhaphy, histologic analysis revealed that the mRFE-treated shoulder joint capsule had almost returned to normal, except for persistent cellularity and increased vascularity, which were present at up to 5 years after this procedure. Level of Evidence: Level III, therapeutic case-control study. [Copyright &y& Elsevier]

Abstract: We investigated intracapsular pressure and elasticity of the hip joint capsule in osteoarthritis. HOOS hip score, sonography of the hip joint, and radiographic assessment of osteoarthritis were performed in 31 patients before total hip arthroplasty. The intracapsular hydrostatic pressure was measured perioperatively, and 0.9% saline solution was then injected in the hip joint, 1 mL at a time, with continuous pressure recording up to 300 mm Hg. The mean radiographic grade of severity of osteoarthritis was 8 (SD, 2.4). The mean hydrostatic intracapsular pressure in 45° of flexion was 2.2 mm Hg (SD, 10.0); in extension, 15.8 mm Hg (SD, 33.0); in inward rotation, 13.7 mm Hg (SD, 26.0); and in outward rotation, 12.1 mm Hg (SD, 24.3). Severe osteoarthritis was associated with lower intracapsular pressure and lower elasticity of the joint capsule. [Copyright &y& Elsevier]

Purpose: Lumbar spinal manipulation (SM) is a popular, effective treatment for low back pain but the physiological mechanisms remain elusive. During SM, mechanoreceptors innervating the facet joint capsule (FJC) may receive a novel stimulus, contributing to the neurophysiological benefits of SM. The biomechanics of SM and physiological axial rotations were compared to determine whether speed or loading site affected FJC strain magnitudes or patterns. Methods: Human lumbar spine specimens were tested during physiological rotations and simulated SM while measuring applied torque, vertebral motion, and FJC strain. During physiological rotations, specimens were actuated at T12 to 20° left and right axial rotation at 2° to 125° per second. During SM simulations, a 7-mm impulse displacement was applied to L3, L4, or L5 at 5 to 50 mm per second. Results: Physiological rotations. Increasing displacement rate resulted in significantly larger torque magnitudes (P <.001), whereas vertebral kinematics and FJC strain magnitudes were unchanged (P > .05). Physiological rotations vs SM. Applied torque and vertebral rotation magnitudes were similar across speed and vertebral level. Total vertebral translations were slightly larger during physiological rotations vs SM at a given loading rate (P <.05). Patterns of vertebral motions and FJC strain during SM and physiological rotations varied significantly with loading rate (P <.05) but not with actuation site (P > .15). Conclusions: The similar patterns observed in vertebral motion and FJC strain across actuation sites during SM and physiological rotations suggest that site specificity of SM may have minimal clinical relevance. High loading rates during lumbar SM resulted in unique patterns in FJC strain, which may result in unique patterns of FJC mechanoreceptor response. [ABSTRACT FROM AUTHOR]

Extraskeletal chondromas are rare benign cartilaginous tumors. Clinically, these tumors are most frequently found in the hands and feet. However, it is extremely rare for them to develop in the oral and maxillofacial regions. We present the case of a 50-year-old man with a tumor lesion of the temporomandibular joint capsule, which is a site that has not been described previously. Based on the physical examination and imaging study, the tumor was located in the joint capsule, and it was locally excised and pathologically diagnosed as extraskeletal chondroma. Postoperatively, residual disability and tumor recurrence were not observed. [ABSTRACT FROM AUTHOR]

Abstract: Ankle arthroscopy has become a standard surgical technique for the treatment of many ankle pathologies. Over the past 30 years, the technique has undergone modification and standardization in order to improve surgical performance and outcomes. In contrast to the ankle joint, the hip joint is a deep joint, which makes visualization and palpation of the topographical anatomy quite difficult. The use of fluoroscopy has enabled the surgeon to successfully perform hip arthroscopy for the treatment of selective hip pathologies. Fluoroscopy also can improve the localization of the anteromedial portal for use in ankle arthroscopy. This technique is valuable for the less-experienced ankle arthroscopist, in resident education, and for the experienced arthroscopist when surface anatomy palpation and visualization is less than ideal due to soft tissue edema and obesity. [Copyright &y& Elsevier]