The subacromial bursa modulates tendon healing after rotator cuff injury in rats.

Rotator cuff injuries result in more than 500,000 surgeries annually in the United States, many of which fail. These surgeries typically involve repair of the injured tendon and removal of the subacromial bursa, a synovial-like tissue that sits between the rotator cuff and the acromion. The subacromial bursa has been implicated in rotator cuff pathogenesis and healing. Using proteomic profiling of bursa samples from nine patients with rotator cuff injury, we show that the bursa responds to injury in the underlying tendon. In a rat model of supraspinatus tenotomy, we evaluated the bursa's effect on the injured supraspinatus tendon, the uninjured infraspinatus tendon, and the underlying humeral head. The bursa protected the intact infraspinatus tendon adjacent to the injured supraspinatus tendon by maintaining its mechanical properties and protected the underlying humeral head by maintaining bone morphometry. The bursa promoted an inflammatory response in injured rat tendon, initiating expression of genes associated with wound healing, including Cox2 and Il6. These results were confirmed in rat bursa organ cultures. To evaluate the potential of the bursa as a therapeutic target, polymer microspheres loaded with dexamethasone were delivered to the intact bursae of rats after tenotomy. Dexamethasone released from the bursa reduced Il1b expression in injured rat supraspinatus tendon, suggesting that the bursa could be used for drug delivery to reduce inflammation in the healing tendon. Our findings indicate that the subacromial bursa contributes to healing in underlying tissues of the shoulder joint, suggesting that its removal during rotator cuff surgery should be reconsidered.

Calcific bursitis of the Gruberi bursa: a case report.

BACKGROUND: Bursitis is the inflammation of a synovial bursa, a small synovial fluid-filled sac that acts as a cushion between muscles, tendons, and bones. Further, calcific bursitis results from calcium deposits on the synovial joint that exacerbates pain and swelling. The Gruberi bursa is located dorsolaterally in the ankle, between the extensor digitorium longus and the talus. Despite limited literature on its pathophysiology, the aim of this case is to discuss the bursa's association with calcific bursitis and its management via a case presented to our clinic. CASE PRESENTATION: A 47-year-old Caucasian female with no past medical or family history presents with acute right ankle pain following a minor injury 3 months prior with no improvement on analgesic or steroid therapy. Imaging demonstrated incidental calcium deposits. The day prior to presentation, the patient stated she used 1-pound ankle weights that resulted in mild swelling and gradual pain to the right dorsoanterior ankle. Physical exam findings displayed a significant reduction in the range of motion limited by pain. Imaging confirmed calcification within the capsule of the talonavicular joint, consistent with Gruberi bursitis. Initial management with prednisone yielded minimal improvement, requiring an interventional approach with ultrasound-guided barbotage that elicited immediate improvement. CONCLUSION: The presented case report highlights a rare and unique instance of acute ankle pain and swelling caused by calcific Gruberi bursitis in a young female. Although the Gruberi bursa is a relatively new discovery, it contains inflammatory components that may predispose it to calcification and should be considered in the differential of ankle swelling. Therefore, utilizing a systematic approach to a clinical presentation and considering all differential diagnoses is essential.

Suprapatellar pouch effusion is associated with an increased risk of neglected osteochondral fractures in primary acute traumatic patellar dislocation: a consecutive series of 113 children.

BACKGROUND: The aim of this study was to investigate the risk factors of neglected osteochondral fractures in primary acute traumatic patellar dislocation in the pediatric population. METHODS: A total of 113 patients with primary acute traumatic patellar dislocation for whom coincident osteochondral fractures could not be confirmed by X-ray examination at initial diagnosis between January 2010 and February 2022 were retrospectively analyzed. Medical history, physical examination, and radiographic images were recorded in detail. The greatest dimension of the suprapatellar pouch (SP) effusion on radiograph was measured. Computed tomography and magnetic resonance imaging were used to confirm the presence of neglected osteochondral fractures and measure the fragment size. Potential risk factors were calculated and correlated with reference to the neglected osteochondral fractures and fragment size using multivariate linear regression analysis. RESULTS: Weight, walking ability, effusion grade, and SP measurement had a significant correlation with neglected osteochondral fractures in primary acute traumatic patellar dislocation (p = 0.046; p < 0.001; p = 0.048; p < 0.001). The cutoff point was 53.5 kg for weight and 18.45 mm for SP measurement. In the neglected fractures group, SP measurement was statistically significant with larger fragment size (beta value = 0.457; p < 0.001), and the cutoff point was 26.2 mm. CONCLUSIONS: SP effusion is not only associated with an increased risk of neglected osteochondral fractures in primary acute traumatic patellar dislocation but also with larger fragment size. Knee radiograph, medical history, and physical examination can predict the need for further imaging examination and even surgery in primary acute traumatic patellar dislocation.

Cystic lesions and bursae around the knee: do they matter in knee osteoarthritis?

The cause of knee osteoarthritis (OA) and knee pain associated with OA is not well understood. Periarticular cystic lesions and bursae around the knee are among the most common morphologic features identified on MRI in the setting of OA. Despite widespread association of these lesions with knee OA and their inclusion in semiquantitative MRI scoring assessment systems for knee OA, the role that these lesions play in the development of knee pain and OA remains uncertain. In this discussion, we review the cystic lesions and bursae most commonly associated with OA of the knee, examine their relation and role in whole organ imaging assessments of OA, and present the literature investigating the associations of periarticular cysts and cyst-like lesions with knee pain and OA.

Anatomy of the congenital calcaneal bursae in the bovine.

OBJECTIVE: The objective of this study was to determine the anatomical relationship of the congenital calcaneal bursae in the bovine, and describe the computed tomography (CT), endoscopic and gross anatomy of these bursae. STUDY DESIGN: Ex vivo experimental. SAMPLE POPULATION: Eighteen clinically normal cadaver bovine hindlimbs. METHODS: Intrasynovial injection of iodinated contrast and methylene blue into the intertendinous calcaneal bursa (ICB) (n = 16) or gastrocnemius calcaneal bursa (GCB) (n = 2). Limbs were imaged post-contrast injection using multidetector CT. Endoscopic examination of the ICB was performed on two randomly selected limbs. All limbs underwent gross anatomical dissection. RESULTS: The anatomy of the congenital calcaneal bursae was consistent between CT imaging, endoscopic examination and gross dissection. The ICB and GCB were two separate synovial structures with no communication in all limbs. The distal and proximal extent of the ICB, defined as the distance from the point of tuber calcanei to the distal/proximal aspect of the ICB, was (median [IQR]) 7.4 (7.4 to 7.8) cm distally and 5.4 (4.7 to 6.0) cm proximally. CONCLUSION: Positive contrast CT and gross anatomical dissection revealed no communication between the congenital calcaneal bursae in any limb. Routine bursoscopy allowed complete endoscopic examination of the ICB. The proximal extent of the ICB is shorter than the distal extent. The use of a collective term for these bursae should be avoided in the bovine, as the ICB and the GCB are two separate synovial structures with no communication. CLINICAL SIGNIFICANCE: Knowledge of distinct anatomy and relationship between the congenital calcaneal bursae in the bovine may facilitate diagnosis and treatment of disorders affecting the region of tuber calcanei, including septic bursitis and osteomyelitis.

Biomolecules Related to Rotator Cuff Pain: A Scoping Review.

The pathophysiology of pain in patients suffering from rotator cuff (RC) tendinopathy or tears has been examined in various ways. Several molecules from tissue samples taken from the subacromial bursa, supraspinatus tendon, glenohumeral joint fluid, and synovium as well as from peripheral blood have been investigated. This article explores these studies, the assessed biomarkers, and groups their results according to the status of tendon integrity (tendinopathy or tear). Through a structured PubMed database search, 9 out of 658 articles were reviewed. Interleukins, mostly IL-1b and its antagonist, IL-1ra, matrix Metalloproteinases (MMPs), the vascular endothelial growth factor (VEGF) and TNF-a are biomarkers directly searched for correlation to pain level. Most studies agree that IL-1b is directly positively correlated to the degree of pain in patients with RC tendinopathy, especially when the examined sample is taken from the subacromial bursa. VEGF, and TNF-a have been related to shoulder pain preoperatively and TNF-a has also been linked with sleep disturbance. Further studies pointing to more biomarkers taken from the subacromial bursa or tendon directly relating to pain degree are warranted.

MR Imaging of the Knee Bursae and Bursal Pathology.

The main function of the knee bursae is to provide cushioning for the many periarticular ligaments, tendons, and osseous structures. Bursae can only be visualized when distended by fluid, therefore bursal anatomy is best evaluated by MR imaging using fluid-sensitive sequences. Knowledge of the normal bursal distribution is important to avoid incorrectly interpreting a distended bursa as a periarticular fluid collection or cyst. Bursal pathology usually results from trauma, chronic overuse, or inflammation, and may be associated with an underlying intra-articular process, given the presence of synovial lining and different degrees of communication with the joint.

Editorial Commentary: Subacromial Bursa May Possess Mesenchymal Progenitor Cells.

Subacromial bursal tissue biopsied during arthroscopic surgery for full-thickness rotator cuff tears appears to possess mesenchymal progenitor cells. Although attempting to harvest mesenchymal progenitor cells from the subacromial bursa for therapeutic purposes may currently be premature, the presence of these cells in bursal tissue does call into question the routine practice of subacromial bursectomy. To maximize the chances of healing after rotator cuff repair, perhaps it would be best to avoid excising non-diseased-appearing bursal tissue any more than what is absolutely necessary to facilitate visualization.

Imaging features of reactive bursitis secondary to osteochondroma.

PURPOSE: The purpose of this study was to determine imaging features of reactive bursitis secondary to osteochondroma. MATERIALS AND METHODS: Fourteen patients with reactive bursitis secondary to osteochondroma were retrospectively reviewed. RESULTS: The 14 patients were 11 males and 3 females ranging in age from 18 to 67 years (mean, 33.6 years). The locations were as follows: scapula (n = 2), lesser trochanter (n = 6), greater trochanter (n = 1), distal femur (n = 2), distal fibula (n = 1), iliac bone (n = 2). On CT, six bursae were hypodense and 1 was isodense compared to muscle. All bursae had a thickened wall, 6 contained multiple villous projections and septa. Five bursae contained a few calcifications. On enhanced CT, the bursa displayed mild enhancement of the wall, villous projections, and septa. On MRI, one bursa was hypointense, three were hyperintense, and 5 were isointense relative to muscles on T1-weighted images. All bursae were hyperintense relative to muscles on T2-weighted images. All bursae had a thickened wall, eight contained multiple villous projections and septa. In five bursae, a few fatty villous projections can be seen within the bursa. On enhanced MRI, all bursae displayed avid enhancement of the bursal wall, villous projections, and septa. CONCLUSIONS: Reactive bursitis secondary to osteochondroma most often occurred in young male adults. The most common involved site is lesser trochanter. The imaging features is that of an irregular, thick-walled fluid-filled bursa overlying an osteochondroma that containing multiple villous projections and septa. Calcification and/or lipoma arborescens may be developed within the bursa. On contrast-enhanced images, the bursa shows enhancement of the bursal wall, villous projections and septa.

Subacromial Bursa: A Neglected Tissue Is Gaining More and More Attention in Clinical and Experimental Research.

The subacromial bursa has long been demolded as friction-reducing tissue, which is often linked to shoulder pain and, therefore, partially removed during shoulder surgery. Currently, the discovery of the stem cell potential of resident bursa-derived cells shed a new light on the subacromial bursa. In the meanwhile, this neglected tissue is gaining more attention as to how it can augment the regenerative properties of adjacent tissues such as rotator cuff tendons. Specifically, the tight fibrovascular network, a high growth factor content, and the large progenitor potential of bursa-derived cells could complement the deficits that a nearby rotator cuff injury might experience due to the fact of its low endogenous regeneration potential. This review deals with the question of whether bursal inflammation is only a pain generator or could also be an initiator of healing. Furthermore, several experimental models highlight potential therapeutic targets to overcome bursal inflammation and, thus, pain. More evidence is needed to fully elucidate a direct interplay between subacromial bursa and rotator cuff tendons. Increasing attention to tendon repair will help to guide future research and answer open questions such that novel treatment strategies could harvest the subacromial bursa's potential to support healing of nearby rotator cuff injuries.

Imaging features of lipoma arborescens.

BACKGROUND: Lipoma arborescens is characterized by the villous proliferation of the synovium and diffuse hyperplasia of fatty tissue in the subsynovial layer, almost always with a periarticular lesion. According to past articles, fewer cases have depicted the imaging features of lipoma arborescens. PURPOSE: To evaluate the computed tomography (CT) and magnetic resonance imaging (MRI) features of lipoma arborescens. MATERIAL AND METHODS: The imaging features of 15 patients with pathologically proven lipoma arborescens were retrospectively analyzed including lesion number, shape, location, size, margins, attenuation on CT, and signal intensity and enhancement patterns on MR images. RESULTS: All cases (n=15) showed joint or bursa effusion. The primary lesion attached to the bursa wall adjacent to the bone in 13 cases and to the lateral wall in two cases. CT shows a mass with fatty tissue attenuation values in the suprapatellar pouch (n=3) or subdeltoid bursa with an erosion of the humeral head (n=2), among them two cases showed branched slightly high density in the center of the fat density tissue. Fifteen cases on routine MRI display mass-like subsynovial mass with fatty tissue signal on all of the sequences and suppression of the signal on fat-suppression sequences. Among them, five lesions showed branched slightly low T1-weighted imaging, high proton density-weighted imaging, and T2-weighted imaging signals in the center. It showed the enhancement of the linear surface and the bursa wall in contrast-enhanced MRI (n=3). CONCLUSION: Lipoma arborescens have specific CT and MRI features that enable them to make a conclusive diagnosis of this rare condition, which helps the diagnosis before treatment.

Quercetin ameliorates ochratoxin A-Induced immunotoxicity in broiler chickens by modulation of PI3K/AKT pathway.

Ochratoxin A (OTA) is a fungal secondary metabolite produced by certain species of Aspergillus and Penicillium, and exerts immunosuppressive effect on humans and animals. Quercetin (QUE) is one of the flavonoids produced as a plant-secondary metabolite. The present study was designed to evaluate the efficacy of QUE against the immunotoxic hazard of OTA in broiler chickens. Forty one-day-old broiler chicks were randomly and equally allocated into four groups; control, OTA (0.5 mg/kg feed), QUE (0.5 g/kg feed) and OTA + QUE (0.5 mg/kg OTA + 0.5 g/kg QUE). The results revealed that dietary OTA induced a significant decrease in the antibody response to Newcastle Disease (ND), Infectious Bronchitis (IB) and Avian Influenza (AI) vaccination and in the lymphoproliferative response to Phytohemagglutinin-P (PHA-P). Ochratoxin A also induced oxidative stress and lipid peroxidation in the bursa of Fabricius, spleen and thymus tissues of chickens as demonstrated by decreased CAT and GSH levels and increased TBARS content. In addition, administration of OTA resulted in apoptosis, which was evident by the increased expression level of PTEN, Bax and Caspase-3 genes and decreased expression level of PI3K, AKT and Bcl-2 genes. Furthermore, exposure to OTA resulted in various pathological lesions in the bursa of Fabricius, spleen and thymus of chickens. On the other hand, administration of QUE ameliorated most of the immunotoxic effects of OTAby its immunomodulatory, antioxidant and anti-apoptotic activities. Taken together, the results suggested that QUE potentially alleviated the OTA-induced immunotoxicity in broiler chickens, probably through amelioration of oxidative stress and activation of the PI3K/AKT signaling pathway.

Characterization of murine subacromial bursal-derived cells.

PURPOSE/AIM: The purpose of this study is to identify a cell population within the murine subcromial bursal-derived cells with characteristics compatible to an accepted mesenchymal stem cell description given by the International Society for Cellular Therapy (ISCT). MATERIALS AND METHODS: Murine subacromial bursa was harvested using microsurgical technique. Subacromial bursal-derived cells were classified through colony-forming units, microscopic morphology, fluorescent-activated cell sorting, and differentiation into chondrogenic, adipogenic, and osteogenic lineages. RESULTS: Subacromial bursal samples exhibited cell growth out of the tissue for an average of 115 ± 29 colony-forming units per 1 mL of complete media. Subacromial bursal-derived cells exhibited a long, spindle-shaped, fibroblast-like morphology. Subacromial bursal-derived cells positively expressed mesenchymal stem cell markers CD73, CD90, and CD105, and negatively expressed mesenchymal stem cell markers CD31 and CD45. Subacromial bursal-derived cells, examined by Image J analysis and quantitative gene expression, were found to differentiate into chondrogenic, adipogenic, and osteogenic lineages. CONCLUSIONS: This study demonstrated the feasibility of harvesting murine subacromial bursal tissue and identified a cell population within the subacromial bursa with characteristics compatible to an accepted mesenchymal stem cell description. The results of this study suggest that the mouse subacromial bursal-derived cell population harbors mesenchymal stem cells. Murine subacromial bursal tissue is a potential source for obtaining cells with mesenchymal stem cell characteristics for future utilization in orthopedic research to look into treatment of rotator cuff pathology.

Subacromial Bursal Tissue and Surrounding Matrix of Patients Undergoing Rotator Cuff Repair Contains Progenitor Cells.

PURPOSE: To build upon previous literature to identify a complete analysis of cellular contents of subacromial bursal tissue as well as the matrix surrounding the rotator cuff. METHODS: Samples of subacromial bursal tissue and surrounding matrix milieu from above the rotator cuff tendon and above the rotator cuff muscle bellies were obtained from 10 patients undergoing arthroscopic rotator cuff repair. Samples were analyzed using fluorescent-activated cell sorting and histologic analysis with staining protocols (Oil Red O, Alcian Blue, and Picro-Sirius Red), for identification of matrix components, including fat, proteoglycans, and collagen. RESULTS: Progenitor cells and fibroblast-type cells were present in significant amounts in subacromial bursal tissue in both tissues obtained from over the tendinous and muscle belly portions. Markers for neural tissue, myeloid cells, and megakaryocytes also were present to a lesser extent. There were prominent amounts of fat and proteoglycans present in the matrix, based on ImageJ analysis of stained histologic slides. CONCLUSIONS: The subacromial bursal tissue and surrounding matrix of patients undergoing rotator cuff repair contains progenitor cells in significant concentrations both over the tendon and muscle belly of the rotator cuff. CLINICAL RELEVANCE: This presence of progenitor cells, in particular, in the subacromial bursal tissue provides a potential basis for future applications of augmentation purposes in rotator cuff healing, and calls into question the practice of routine bursectomy. As the potential role of bursal tissue contents in growth and regeneration in the setting of rotator cuff healing is more well understood, maintaining this tissue may become more relevant. Concentration of these cellular components for use in autologous re-implantation is also an avenue of interest.

Ultrasound Guidance Is Not Superior in Subacromial Bursa and Intraarticular Injections but Superior in Bicipital Groove: A Meta-analysis of Randomized Controlled Trials.

PURPOSE: To perform a meta-analysis comparing the clinical and functional outcomes of ultrasound-guided (USG) and blind injections for shoulder pain. METHOD: The Embase, Cochrane Library, and PubMed databases were searched from database inception to April 7, 2021. Clinical and functional outcomes included the visual analog scale (VAS) pain score, abduction, flexion, American Shoulder and Elbow Surgeons Assessment Form (ASES) score, Constant-Murley Shoulder (CMS) score, Shoulder Pain and Disability Index (SPADI), Shoulder Disability Questionnaire (SDQ) score, and Shorted Disabilities of the Arm, Shoulder and Hand (Quick DASH) score. Dichotomous outcomes were assessed with mean differences (MDs) and 95% confidence intervals (95% CIs). RESULTS: Fifteen studies that compared USG and blind injections were included. No significant difference was found in the VAS score between the blind group and USG group (MD 0.41 [-0.02, 0.84]; I2 = 79%; P = .06). Subgroup analysis of the brachial bicipital groove indicated that the USG group had less pain than the blind group (MD 1.50 [0.54, 2.46]; I2 = 64; P = .002). The USG injection patients had better postoperative abduction (MD -3.08 [-5.19, -0.98], I2 = 0, P = .004) and flexion (MD -3.36 [-5.56, -1.16]; I2 = 0; P = .003) than the blind group. Additionally, the USG injection patients had better CMS scores than the blind injection patients (MD -12.95 [-25.60, -0.29]; I2 = 96; P = .04). However, subgroup analysis showed no significant difference in the subacromial bursas and glenohumeral joints of CMS score (MD -13.22 [-29.93, 3.94]; I2 = 97; P＜.0001). No significant difference was found in the SPADI, ASES score, or SDQ score between the groups. CONCLUSIONS: Ultrasound guidance is not superior in the subacromial bursa and glenohumeral joint injections in pain or function. However, injection in the brachial bicipital groove, is still superior to blind injection of pain relief. LEVEL OF EVIDENCE: Level II, meta-analysis of Level I and II studies.

Editorial Commentary: Point-of-Care Harvest and Application of Resident Stem Are Practical and Cost-Effective.

Point-of-care harvest and application of residence stem cells are practical and cost-effective. Tissue formerly considered waste contains these biologically potent cells, and use of such tissue may represent a big part of biologics going forward. The practical application of orthobiologics has slowed because of 3 hurdles: the regulatory requirements of stem cell technologies; the energy, time, and money required to develop a clinical evidence base; and the expense that they present to patients and institutions. Orthobiologic technologies that are simple and cheap and that leverage tissues that are already readily available at the point of care (i.e., the surgical procedure) solve many of these challenges. Cell sources could include knee synovium, shoulder subacromial bursa, bone marrow aspirate, and anterior cruciate ligament injury effusion fluid and stump tissue. A current concern is that collagenase processing and culture expansion are steps resulting in regulatory hurdles in the United States.

Factors affecting successful ultrasound-guided injection into the podotrochlear bursa using a palmarolateral approach.

OBJECTIVE: To evaluate potential factors affecting ultrasonographic visibility of the suprasesamoidean region and the success rate of ultrasound-guided injection (USGI) into the podotrochlear bursa (PB). STUDY DESIGN: Ex vivo, experimental study. ANIMALS: 24 cadaveric forelimbs. METHODS: The PB was distended with 0, 1, or 2 ml of iodinated contrast material and saline under radiographic guidance. Ultrasonographic visibility of the suprasesamoidean region and PB was graded before and after distention with the limb loaded in three positions (vertical, cranial and caudal). Two operators with different experience levels performed an USGI into the PB with methylene blue (12 limbs each [four limbs with each of three volumes of PB distension]) using a palmarolateral approach and caudal foot placement. Limbs were frozen and sectioned to assess accuracy. RESULTS: Ultrasonographic visibility scores of the suprasesamoidean region (p = .0081) and PB (p < .0001) were improved using a caudal foot placement. Higher visibility grades of the suprasesamoidean region were associated with higher injection success rate (p = .047). The injection success was 75% (9/12) for the experienced versus 41.6% (5/12) for the less experienced operator (p = .14). PB distension improved visibility during caudal foot placement (p = .013) but not injection success rates (p = .78). CONCLUSION: Caudal foot placement enhances visibility of the PB and suprasesamoidean region. Limbs with poor visibility of the suprasesamoidean region are more likely to undergo a failed USGI. CLINICAL SIGNIFICANCE: The lateral USGI approach should be performed only in cases of optimal visibility. The reported success rates support the technical challenge of PB injections.

Neglected tuberculous trochanteric bursitis in an adolescent girl: A case report and literature review.

Tuberculous trochanteric bursitis (TTB) is an extremely rare form of extrapulmonary tuberculosis. Due to a low clinical suspicion and poor collaboration among medical professionals, the diagnosis of TTB can be often delayed. In this report, we describe a case of neglected TTB in an adolescent girl that initially presented with right thigh swelling and fluctuance. The patient underwent repeated unsuccessful surgical treatment; however, dull pain and periodic wound drainage remained for eight years. Complete excision of fistula and trochanteric bursa and one year of oral antituberculous drug therapy led to complete recovery. This case report highlights tuberculosis as a diagnostic challenge, when rare localizations are affected. In addition, this report addresses several diagnostic pitfalls and reviews the literature regarding TTB in adolescent patients. Orthopedic surgeons need to consider TTB, when swelling, fluctuance or repeated wound drainage are present on the thigh.