Distinctiveness of Femoral and Acetabular Mesenchymal Stem and Progenitor Populations in Patients with Primary and Secondary Hip Osteoarthritis Due to Developmental Dysplasia.

Primary hip osteoarthritis (pOA) develops without an apparent underlying reason, whereas secondary osteoarthritis arises due to a known cause, such as developmental dysplasia of the hips (DDH-OA). DDH-OA patients undergo total hip arthroplasty at a much younger age than pOA patients (50.58 vs. 65 years in this study). Recently, mesenchymal stem and progenitor cells (MSPCs) have been investigated for the treatment of osteoarthritis due to their immunomodulatory and regenerative potential. This study identified cells in subchondral bone expressing common MSPC markers (CD10, CD73, CD140b, CD146, CD164, CD271, GD2, PDPN) in vivo and compared the proportions of these populations in pOA vs. DDH-OA, further correlating them with clinical, demographic, and morphological characteristics. The differences in subchondral morphology and proportions of non-hematopoietic cells expressing MSPC markers were noted depending on OA type and skeletal location. Bone sclerosis was more prominent in the pOA acetabulum (Ac) in comparison to the DDH-OA Ac and in the pOA Ac compared to the pOA femoral head (Fh). Immunophenotyping indicated diagnosis-specific differences, such as a higher proportion of CD164+ cells and their subsets in DDH-OA, while pOA contained a significantly higher proportion of CD10+ and GD2+ cells and subsets, with CD271+ being marginally higher. Location-specific differences showed that CD271+ cells were more abundant in the Fh compared to the Ac in DDH-OA patients. Furthermore, immunohistochemical characterization of stromal bone-adjacent cells expressing MSPC markers (CD10, CD164, CD271, GD2) in the Ac and Fh compartments was performed. This research proved that immunophenotype profiles and morphological changes are both location- and disease-specific. Furthermore, it provided potentially effective targets for therapeutic strategies. Future research should analyze the differentiation potential of subsets identified in this study. After proper characterization, they can be selectively targeted, thus enhancing personalized medicine approaches in joint disease management.

Novel micro-MRI approach for subchondral trabecular bone analysis in patients with hip osteoarthritis is comparable to micro-CT approach.

AIM: To test the agreement between a newly developed micro-magnetic resonance imaging (MRI) analysis of the subchondral bone and the micro-computed tomography (CT) approach. METHODS: Samples obtained from 10 patients with osteoarthritis undergoing total hip arthroplasty were scanned with a 7.0 T micro-MRI. Proton density-weighted images and proton density-weighted images with fat suppression were obtained. The results were validated with a micro-CT device. Micro-MRI and micro-CT scans of the same sample were aligned, and regions of interest were delineated on equal areas of the sample. Bone volume fraction was calculated by using in-house plugins. The agreement between the methods was tested with Bland-Altman analysis. RESULTS: The agreement between the methods was good, with average difference of 2.167%. The differences between the methods were not significant (P=0.272, t test). CONCLUSION: The novel micro-MRI approach could be used for subchondral bone analysis. With further optimization for clinical MRI machines, the approach can be also used in the diagnostics of hip osteoarthritis.

IMPACT OF CEMENTLESS ZWEYMÜLLER STEM ANTEVERSION ON RESISTANCE TO PERIPROSTHETIC FRACTURE IN TOTAL HIP ARTHROPLASTY.

Total hip arthroplasty implies proper orientation of both acetabular and femoral components with a range of 25-40° of combined anteversion. The aim of the study was to examine resistance to periprosthetic fracture of the axially loaded cross section rectangular femoral stem (Zweymüller) with respect to different degrees of anteversion, implanted in the artificial bone model, in laboratory conditions. Femoral bone models with implanted femoral stems were divided into 3 groups depending on the degree of stem anteversion (A, control group 13-17°; B, stem retroverted 0°-4°; and C, stem anteverted 26-30°). The amount of axial load leading to periprosthetic fracture (PPFx) of the artificial bone model was determined experimentally for each construct. The results showed that the load at which the PPFx occurred significantly increased with the increase of the endoprosthesis anteversion angle. In our clinical practice, we are often unable to place the acetabular component in an ideal grade of anteversion for intraoperatively determined reasons. The results of this experimental study suggested that increasing rectangular femoral (Zweymüller) stem anteversion lowered the risk of PPFx. This study was limited by experimental design (laboratory conditions, artificial bone) and should be clinically verified.

Risk factors for subsidence of modular fluted tapered stem implanted by using transfemoral Wagner approach during revision hip arthroplasty.

PURPOSE: To determine clinical and radiographic risk factors for the vertical subsidence of modular fluted tapered stems implanted using the transfemoral Wagner approach in a cohort of revision hip arthroplasties. METHODS: A retrospective review of a single-centre surgical registry was performed. Patients who underwent a revision total hip arthroplasty, in which the uncemented modular fluted tapered stem (REVISION Hip/Anca-Ti6Al4V, LimaCorporate, Udine, Italy) was implanted using the transfemoral Wagner approach, were identified. Patient's demographic data, clinical and radiographic outcomes and post-operative complications were assessed. As a significant subsidence, a 5-mm cut-off was chosen. RESULTS: We identified 278 revision hip arthroplasties with a mean follow-up of 35 months. The median of subsidence in the group of 5 mm and less was 2 mm, and 17 mm in the group of subsidence of 5 mm and more. A negative correlation was found between the stem subsidence and the length of good contact between the medial and lateral cortical bone and the stem (medial, - 0.248; P < 0.001, lateral, 0.284; P < 0.001). For 200 mm stems, the percentage of good contact between femoral parts of stem and bone on medial side was 40.5% (81.0 mm) for patients with subsidence of five or less mm, and 30% (60.0 mm) for lateral side. For 140 mm stems, the percentage was 52.86% (74.0 mm) for medial side and 40.36% (56.5 mm) for lateral side. A neck length was shown to correlate significantly with the stem subsidence (P = 0.004). CONCLUSION: It is crucial to provide good contact between the bilateral cortical bone and stem, and, if possible, to select implant constructs with shorter femoral necks, in order to reduce subsidence and to ensure longer implant survivorship.

Current knowledge on the genetic background of developmental dysplasia of the hip and the histomorphological status of the cartilage.

Developmental dysplasia of the hip (DDH) represents a morphological abnormality characterized by the incongruity of femoral head and acetabulum. It ranges from mild dysplastic changes to complete dislocation. DDH has been associated with several hereditary and environmental risk factors, which could explain the incidence variability among different countries. Numerous genes may be involved in the disease etiology and progression. However, there are controversies in the literature regarding some of these genes. DDH-induced secondary osteoarthritis (OA) is characterized by changes in the macromolecule content of the cartilage and the expression of cartilage degradation markers. In addition, it exhibits a pattern of specific histological changes, with several reported differences between primary and DDH-induced secondary OA. The articular cartilage of patients with DDH shows specific radiological characteristics, including changes visible already in infancy, but also at pre-arthritic stages, early stages of OA, and in fully developed DDH-induced secondary OA. Although DDH has been extensively researched in different disease stages, the etiology of the disorder still remains uncertain. This review focuses on the current knowledge on the histomorphological status of the cartilage and the genetic background of DDH.

Applications and critical evaluation of fascia iliaca compartment block and quadratus lumborum block for orthopedic procedures.

Anterior section of the hip joint capsule is innervated by femoral nerve and obturator nerve, and posterior section is innervated by the nerve to quadratus femoris muscle and occasionally by the superior gluteal (posterolateral region) and sciatic nerve (posterosuperior region). One of the regional anesthesia options for hip surgery is the fascia iliaca compartment block (FICB) that affects nerves important for hip innervation and sensory innervation of the thigh - femoral, obturator and lateral femoral cutaneous nerve. FICB can be easily performed and is often a good solution for management of hip fractures in emergency departments. Its use reduces morphine pre-operative requirement for patients with femoral neck fractures and can also be indicated for hip arthroplasty, hip arthroscopy and burn management of the region. Quadratus lumborum block (QLB) is a block of the posterior abdominal wall performed exclusively under ultrasound guidance, with still unclarified mechanism of action. When considering hip surgery and postoperative management, the anterior QLB has shown to reduce lengthy hospital stay and opioid use, it improves perioperative analgesia in patients undergoing hip and proximal femoral surgery compared to standard intravenous analgesia regimen, provides early and rapid pain relief and allows early ambulation, thus preventing deep vein thrombosis and thromboembolic complications etc. However, some nerve branches responsible for innervation of the hip joint are not affected by QLB, which has to be taken into consideration. QLB has shown potential for use in hip surgery and perioperative pain management, but still needs to be validated as a reliable treatment approach.

Femoral head wear and metallosis caused by damaged titanium porous coating after primary metal-on-polyethylene total hip arthroplasty: a case report.

Excessive metal femoral head wear has been described only as revision surgery complication after primary ceramic-on-ceramic total hip arthroplasty (THA). Here, we present the first case of metal femoral head wear after primary metal-on-polyethylene THA. A 56-year-old woman was referred to our outpatient clinic 17 years after primary right-sided THA, experiencing pain and decreased right hip range of motion. Radiographic examination revealed acetabular cup dislocation, eccentric femoral head wear, damaged titanium porous coating of femoral stem, metallosis, and pseudotumor formation. Endoprosthetic components were extracted, but further reconstruction was impossible due to presence of large acetabular bone defect. Macro- and micro-structure of extracted components were analyzed. Acetabular liner surface was damaged, with scratches, indentations, and embedded metal debris particles present on the entire inner surface. Analysis of metal debris by energy-dispersive spectroscopy showed that it consisted of titanium and stainless-steel particles. Femoral head was gravely worn and elliptically shaped, with abrasive wear visible under scanning electron microscope. No signs of trunnionosis at head/neck junction were observed. Microstructure of femoral head material was homogeneous austenitic, with microhardness of 145 HV 0.2, which is lower than previously described titanium hardness. In conclusion, detached titanium porous coating of femoral stem can cause stainless-steel femoral head wear in primary metal-on-polyethylene THA. As soon as such detachment becomes evident, revision surgery should be considered to prevent devastating complications.

Sport injuries in international masters rowers: a cross-sectional study.

AIM: To estimate the frequency and localization of acute (traumatic) and chronic (overuse) injuries in a population of masters rowers with respect to their age subgroups and assess the association between injury occurrence and different training modalities, rowing experience, previous competition level, and current rowing practice. METHODS: A cross-sectional study was conducted among 743 masters rowers who participated in the 34th International Federation of Rowing Associations (Fédération Internationale des Sociétés d'Aviron, FISA) World Rowing Masters Regatta held in Zagreb, September 2-9, 2007. A rowing-specific questionnaire was used, followed by an interview about the injuries sustained during the 12-month period before the competition. RESULTS: The mean injury rate per year was 0.48 injuries/masters rower (2.25 injuries/1000 training sessions/rower). The majority of injuries were chronic injuries (the ratio of acute to chronic injuries was 1:1.7), and did not lead to the loss of training/competition time. Of all acute injuries, 49.6% were acquired during rowing-specific training, 43.7% during cross-training, and 6.7% in the gym. The most commonly affected region was the low back (32.6%), followed by the knee (14.2%), shoulder/upper arm, and elbow (10.6% each). CONCLUSION: International masters rowers sustained predominantly chronic injuries of low severity, and the most commonly injured region was the low back. The mean injury rate per rower per year was lower than the rates previously reported for juniors and seniors.

Mortality and causes of death among Croatian male Olympic medalists.

AIM: To compare the overall and disease-specific mortality of Croatian male athletes who won one or more Olympic medals representing Yugoslavia from 1948 to 1988 or Croatia from 1992 to 2016, and the general Croatian male population standardized by age and time period. METHODS: All 233 Croatian male Olympic medalists were included in the study. Information on life duration and cause of death for the Olympic medalists who died before January 1, 2017, was acquired from their families and acquaintances. We asked the families and acquaintances to present medical documentation for the deceased. Data about the overall and disease-specific mortality of the Croatian male population standardized by age and time period were obtained from the Croatian Bureau of Statistics (CBS). Overall and disease-specific standard mortality ratios (SMR) with 95% confidence intervals (CI) were calculated to compare the mortality rates of athletes and general population. RESULTS: Among 233 Olympic medalists, 57 died before the study endpoint. The main causes of death were cardiovascular diseases (33.3%), neoplasms (26.3%), and external causes (17.6%). The overall mortality of the Olympic medalists was significantly lower than that of general population (SMR 0.73, 95% CI 0.56-0.94, P=0.013). Regarding specific causes of death, athletes' mortality from cardiovascular diseases was significantly reduced (SMR 0.61, 95% CI 0.38-0.93, P=0.021). CONCLUSIONS: Croatian male Olympic medalists benefit from lower overall and cardiovascular mortality rates in comparison to the general Croatian male population.

OSTEOID OSTEOMA OF THE CORACOID PROCESS: CASE REPORT WITH LITERATURE REVIEW.

Osteoid osteoma (OO) is the most common benign osteogenic bone tumor that predominantly affects young adults. OO is commonly localized in long bones, and therefore, it is rarely considered in differential diagnosis of chronic shoulder pain. We report a case of a 22-year-old male athlete, without history of previous trauma, who presented to our Department with chronic shoulder pain, which escalated during the night and responded to nonsteroidal anti-inflammatory drug treatment. Considering these typical symptoms, diagnostic pathway was immediately directed towards OO, with magnetic resonance and computed tomography confirming the diagnosis of OO of the coracoid process (CP). Since neurovascular structures are in the proximity of CP, and this very delicate area does not support radiofrequency ablation, we decided to perform an open procedure with drilling of the lesion and excochleation. The pain withdrew immediately after the procedure, and on six-month follow up the patient remained pain free. In the treatment of OO of the CP, we recommend open surgical procedure with tumor ablation by drilling instead of CP resection, presenting a safe, simple and low-cost method that simultaneously completely destroys the lesion and preserves the anatomical and functional role of CP

Peroneal tendoscopy--more than just a solitary procedure: case-series.

This study presents a series of 13 patients who underwent peroneal tendoscopy as a solitary or accessory procedure at our department in 2013. Patients were clinically diagnosed with peroneal tendons disorders and underwent an additional radiological assessment. Peroneal tendoscopy was carried out in a standard manner before any other arthroscopic or open procedure. Postoperative management depended on the type of pathology. We found 3 peroneus brevis tendon partial tears, 4 cases of a low-lying peroneus brevis muscle belly, 5 cases of tenosynovitis, and 1 case of an intrasheath peroneal tendon subluxation. In 5 patients peroneal tendoscopy was performed as a solitary procedure and in 8 patients as an accessory procedure--together with anterior or posterior ankle arthroscopy, combined posterior and anterior ankle arthroscopy, or open surgery. Both as a solitary and accessory procedure, peroneal tendoscopy was safe and successful, ie, all patients were without any symptoms at one-year follow-up. Our series of patients showed that peroneal tendoscopy can be used both as an independent procedure as well as a valuable accessory procedure.

Acute and chronic injuries among senior international rowers: a cross-sectional study.

PURPOSE: The aim of the study was to define the types of musculoskeletal injuries present in senior international rowers. According to the literature, no such study has been performed in this group. METHODS: Injury data were obtained from a total of 634 rowers (33 % female, 67 % male) who completed a 12-month retrospective questionnaire on injury incidence while participating in the Senior World Rowing Championships in Munich, Germany, in 2007. RESULTS: The mean injury rate per one year was 0.92 injuries per rower (1.75 injuries per 1,000 training sessions per rower). The vast majority of self-reported injuries were chronic injuries (acute vs chronic ratio was 1:2.63), and the majority of reported injuries did not result in loss of time from training or competition. Of all acute injuries, 58.1 % were sustained during rowing-specific training, with 20.6 % injuries sustained in the gym and 21.3 % during cross-training. The most common site of injury was the low back followed by the knee and the chest/thoracic spine. Senior open weight rowers who sustained chronic injuries achieved significantly better final ranking at the 2007 Senior World Rowing Championships compared to the same group of rowers who did not sustain any injury. CONCLUSION: Senior international rowers participating in World Rowing Championships sustained predominantly chronic (overuse) injuries during the rowing season studied. Those were mainly low severity injuries, with the low back being the most frequently injured site. This study may will help in prevention and early diagnosis of eventual injuries in top-level rowers.

Reconstructive surgery after distal fibular resection due to bone tumors: a technical report on surgical strategies and results from the PROSPERO international register of systematic reviews.

Purpose: Primary bone tumors of the fibula are rare. Distal fibular resection has a significant impact on ankle biomechanics and gait, possibly leading to complications such as ankle instability, valgus deformity, and degenerative changes. Question: Is there a need for reconstructive surgery after distal fibular resection, and what reconstructive procedures are available? Materials and methods: The review is registered with the PROSPERO International Register of Systematic Reviews. Inclusion criteria consisted of all levels of evidence, human studies, patients of all ages and genders, publication in English, and resection of the distal portion of the fibula due to tumor pathology. The reviewers defined four different categories of interest by method of treatment. Additional articles of interest during full-text review were also added. Results: The initial search resulted with a total of 2958 records. After screening, a total of 50 articles were included in the study. Articles were divided into 'No reconstruction', 'Soft tissue reconstruction', 'Bone and soft tissue reconstruction', and 'Arthrodesis, arthroplasty or other reconstruction options' groups. Conclusion: Limb salvage surgery should be followed by reconstruction in order to avoid complications. Soft tissue reconstructions should always be considered to stabilize the joint after fibular resection. Bone reconstruction with reversed vascularized fibula is the preferred technique in young patients and in cases of bone defects more than 3 cm, while arthrodesis should be considered in adult patients. Whenever possible for oncologic reason, if a residual peroneal malleolus could be preserved, we prefer augmentation with a sliding ipsilateral fibular graft.

Specificities in the Structure of the Cartilage of Patients with Advanced Stages of Developmental Dysplasia of the Hip.

Developmental dysplasia of the hip (DDH) presents varying degrees of femoral head dislocation, with severe cases leading to the formation of a new articular surface on the external side of the iliac bone-the neoacetabulum. Despite conventional understanding suggesting otherwise, a tissue resembling hyaline cartilage is found in the neoacetabulum and acetabulum of Crowe III and IV patients, indicating a potential for hyaline cartilage development without mechanical pressure. To test this theory, acetabular and femoral head cartilage obtained from patients with DDH was stained with hematoxylin-eosin and toluidine blue. The immunohistochemical analysis for collagen types II and VI and aggrecan was performed, as well as delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) analysis on a 7.0 T micro-MRI machine. The results obtained from DDH patients were compared to those of the control groups. Hyaline cartilage was found in the neoacetabulum and the acetabulum of patients with DDH. The nature of the tissue was confirmed with both the histological and the MRI analyses. The results of this study proved the presence of hyaline cartilage in patients with DDH at anatomical regions genetically predisposed to be bone tissue and at regions that are not subjected to mechanical stress. This is the first time that the neoacetabular cartilage of patients with advanced stages of DDH has been characterized in detail.

Galectin-3 is required for resident microglia activation and proliferation in response to ischemic injury.

Growing evidence suggests that galectin-3 is involved in fine tuning of the inflammatory responses at the periphery, however, its role in injured brain is far less clear. Our previous work demonstrated upregulation and coexpression of galectin-3 and IGF-1 in a subset of activated/proliferating microglial cells after stroke. Here, we tested the hypothesis that galectin-3 plays a pivotal role in mediating injury-induced microglial activation and proliferation. By using a galectin-3 knock-out mouse (Gal-3KO), we demonstrated that targeted disruption of the galectin-3 gene significantly alters microglia activation and induces ∼4-fold decrease in microglia proliferation. Defective microglia activation/proliferation was further associated with significant increase in the size of ischemic lesion, ∼2-fold increase in the number of apoptotic neurons, and a marked deregulation of the IGF-1 levels. Next, our results revealed that contrary to WT cells, the Gal3-KO microglia failed to proliferate in response to IGF-1. Moreover, the IGF-1-mediated mitogenic microglia response was reduced by N-glycosylation inhibitor tunicamycine while coimmunoprecipitation experiments revealed galectin-3 binding to IGF-receptor 1 (R1), thus suggesting that interaction of galectin-3 with the N-linked glycans of receptors for growth factors is involved in IGF-R1 signaling. While the canonical IGF-1 signaling pathways were not affected, we observed an overexpression of IL-6 and SOCS3, suggesting an overactivation of JAK/STAT3, a shared signaling pathway for IGF-1/IL-6. Together, our findings suggest that galectin-3 is required for resident microglia activation and proliferation in response to ischemic injury.

Computed microtomography visualization and quantification of mouse ischemic brain lesion by nonionic radio contrast agents.

AIM: To explore the possibility of brain imaging by microcomputed tomography (microCT) using x-ray contrasting methods to visualize mouse brain ischemic lesions after middle cerebral artery occlusion (MCAO). METHODS: Isolated brains were immersed in ionic or nonionic radio contrast agent (RCA) for 5 days and subsequently scanned using microCT scanner. To verify whether ex-vivo microCT brain images can be used to characterize ischemic lesions, they were compared to Nissl stained serial histological sections of the same brains. To verify if brains immersed in RCA may be used afterwards for other methods, subsequent immunofluorescent labeling with anti-NeuN was performed. RESULTS: Nonionic RCA showed better gray to white matter contrast in the brain, and therefore was selected for further studies. MicroCT measurement of ischemic lesion size and cerebral edema significantly correlated with the values determined by Nissl staining (ischemic lesion size: P=0.0005; cerebral edema: P=0.0002). Brain immersion in nonionic RCA did not affect subsequent immunofluorescent analysis and NeuN immunoreactivity. CONCLUSION: MicroCT method was proven to be suitable for delineation of the ischemic lesion from the non-infarcted tissue, and quantification of lesion volume and cerebral edema.

Toll-like receptor 2 deficiency leads to delayed exacerbation of ischemic injury.

BACKGROUND: Using a live imaging approach, we have previously shown that microglia activation after stroke is characterized by marked and long-term induction of the Toll-like receptor (TLR) 2 biophotonic signals. However, the role of TLR2 (and potentially other TLRs) beyond the acute innate immune response and as early neuroprotection against ischemic injury is not well understood. METHODS: TLR2-/- mice were subjected to transient middle cerebral artery occlusion followed by different reperfusion times. Analyses assessing microglial activation profile/innate immune response were performed using in situ hybridization, immunohistochemistry analysis, flow cytometry and inflammatory cytokine array. The effects of the TLR2 deficiency on the evolution of ischemic brain injury were analyzed using a cresyl violet staining of brain sections with appropriate lesion size estimation. RESULTS: Here we report that TLR2 deficiency markedly affects post-stroke immune response resulting in delayed exacerbation of the ischemic injury. The temporal analysis of the microglia/macrophage activation profiles in TLR2-/- mice and age-matched controls revealed reduced microglia/macrophage activation after stroke, reduced capacity of resident microglia to proliferate as well as decreased levels of monocyte chemotactic protein-1 (MCP-1) and consequently lower levels of CD45(high)/CD11b(+) expressing cells as shown by flow cytometry analysis. Importantly, although acute ischemic lesions (24 to 72 h) were smaller in TLR2-/- mice, the observed alterations in innate immune response were more pronounced at later time points (at day 7) after initial stroke, which finally resulted in delayed exacerbation of ischemic lesion leading to larger chronic infarctions as compared with wild-type mice. Moreover, our results revealed that TLR2 deficiency is associated with significant decrease in the levels of neurotrophic/anti-apoptotic factor Insulin-like growth factor-1 (IGF-1), expressed by microglia in the areas both in and around ischemic lesion. CONCLUSION: Our results clearly suggest that optimal and timely microglial activation/innate immune response is needed to limit neuronal damage after stroke.

Plantaris tendon is valuable graft for the medial patellofemoral ligament reconstruction: A biomechanical study.

BACKGROUND: Medial patellofemoral ligament (MPFL) reconstruction is a standard treatment option for selected patients with patellar instability. Although frequently performed, the optimal graft source for the procedure has not yet been established. This study aimed to determine whether a two-strand plantaris tendon construct possesses the biomechanical properties needed to act as an MPFL reconstruction graft. METHODS: Thirty paired plantaris and gracilis tendons were harvested from 15 cadavers, mean age at death of 42.7 years. All specimens were frozen and maintained at -20 °C until biomechanical testing. Prior to mechanical testing, specimens were thawed at room temperature. The two-strand plantaris tendon and two-strand gracilis tendon constructs were created and secured in a uniaxial tensile testing machine in a triangular-shaped mode. Biomechanical properties for tensile testing to failure were determined using validated method. Results obtained were compared with the previously published data on native MPFL biomechanical properties. RESULTS: The mean maximal force was 220.3 ± 108.1 N and 448.1 ± 117 N for the two-strand plantaris tendon construct and two-strand gracilis tendon construct, respectively. Significant differences were observed between all biomechanical properties of two-strand plantaris tendon and two-strand gracilis tendon constructs. The mean maximal force of a two-strand plantaris tendon construct and a two-strand gracilis tendon construct were greater than the mean maximal force of the native MPFL reported in all previous studies. CONCLUSIONS: This study suggests that, due to its biomechanical properties, the two-strand plantaris tendon graft is suitable as a graft for MPFL reconstruction.

Accumulation of dietary docosahexaenoic acid in the brain attenuates acute immune response and development of postischemic neuronal damage.

BACKGROUND AND PURPOSE: Consumption of fish has been shown to reduce risk of coronary heart disease and, possibly, of ischemic stroke. Because docosahexaenoic acid (DHA) is the most likely neuroactive component within fish oil, we hypothesized that exposing mice to a DHA-enriched diet may reduce inflammation and protect neurons against ischemic injury. METHODS: To visualize the effects of DHA on neuroinflammation after stroke, TLR2-fluc-GFP transgenic mice were exposed to either a control diet, a diet depleted in n-3 polyunsaturated fatty acid, or a diet enriched in DHA during 3 months. Real-time biophotonic/bioluminescence imaging of the TLR2 response was performed before and after middle cerebral artery occlusion, whereas cytokines concentrations and stroke area analyses were performed at 3 and 7 days after middle cerebral artery occlusion, respectively. RESULTS: We show that a 3-month DHA treatment prevented microglial activation after ischemic injury, reduced the ischemic lesion size, and increased levels of the antiapoptotic molecule Bcl-2 in the brain. Additional analysis revealed a significant decrease in the levels of COX2 and IL-1ß, but not in other proinflammatory cytokines. Importantly, long-term DHA supplementation significantly changed the n-3:n-6 polyunsaturated fatty acid ratio in the brain. CONCLUSIONS: Collectively, these data indicate that diet-induced accumulation of DHA in the brain protects against postischemic inflammation and injury. Because DHA is widely available at low cost and has an excellent safety profile, our data suggest that increased DHA intake may provide protection against acute immune response/brain damage in ischemic stroke.

The neoacetabulum in developmental dysplasia of the hip is covered with hyaline cartilage.

The lack of adequate mechanical stimulation and appropriate contact between acetabulum and femoral head results with developmental dysplasia of the hip (DDH). In DDH, hip joint forms normally during the organogenesis, but deforms during the fetal development. Acetabulum remains comparable in width with normal acetabulum, but has increased length and decreased depth, resulting in a poor coverage of the femoral head. In cases of severe hip subluxation and luxation due to DDH, the femoral head articulates with the external side of the iliac bone, forming a neoacetabulum in the position that was genetically predetermined to become bony tissue. A neoacetabulum is therefore formed under intermittent mechanical pressure, but never has the depth of a physiological acetabulum due to different forces at this new location. Over time, the depth of the neoacetabulum increases, and a crest is formed that obstructs reposition of the femoral head into the anatomic acetabulum. We hypothesize that the neoacetabulum on the iliac bone in DDH patients is formed of hyaline cartilage, despite the lack of genetic predisposition for hyaline cartilage formation in this area. We assume that as the femoral head migrates during development in such patients, joint capsular tissue interposes between the external side of the iliac bone and the femoral head, and a cartilaginous metaplasia of the capsule follows. This results in elongation of the acetabular cartilage in the same direction as the femoral head migrated. This assumption is based on the finding that in patients with hip luxation such interposed joint capsule showed signs of cartilaginous transformation. Furthermore, in the inner part of such joint capsules, proteoglycan production was notably higher than that of other non-cartilaginous tissue. Also, high expression of cartilaginous genes, which are usually not expressed in this tissue, was observed. Confirmation of this hypothesis would put a new perspective on the pathogenesis of DDH and could lead to better management or even prevention of this condition.