Reported rates of dislocation in hip hemiarthroplasty (HA) for the treatment of intra-capsular fractures of the hip, range between 1% and 10%. HA is frequently performed through a direct lateral surgical approach. The aim of this study is to determine the contribution of the anterior capsule to the stability of a cemented HA through a direct lateral approach. . A total of five whole-body cadavers were thawed at room temperature, providing ten hip joints for investigation. A Thompson HA was cemented in place via a direct lateral approach. The cadavers were then positioned supine, both knee joints were disarticulated and a digital torque wrench was attached to the femur using a circular frame with three half pins. The wrench applied an external rotation force with the hip in extension to allow the hip to dislocate anteriorly. Each hip was dislocated twice; once with a capsular repair and once without repairing the capsule. Stratified sampling ensured the order in which this was performed was alternated for the paired hips on each cadaver. . Comparing peak torque force in hips with the capsule repaired and peak torque force in hips without repair of the capsule, revealed a significant difference between the ‘capsule repaired’ (mean 22.96 Nm, standard deviation (. sd. ) 4.61) and the ‘capsule not repaired’ group (mean 5.6 Nm, . sd. 2.81) (p < 0.001). Capsular repair may help reduce the risk of hip dislocation following HA. Cite this article: Bone Joint J 2015;97-B:141–4

Insufficiency of the lateral collateral ligamentous complex causes posterolateral rotatory instability (PLRI). During reconstruction surgery the joint capsule is repaired, but its biomechanical influence on elbow stability has not been described. We hypothesized that capsular repair reduces ROM and varus angle after reconstruction of the lateral collateral complex. Six fresh frozen cadaveric elbow specimens were used. Varus laxity in supination, pronation and neutral forearm rotation with 1 Nm load and forearm rotaitonal range of motion (ROM) with 0.3 Nm torque were measured using a Microscribe 3DLX digitizing system (Revware Inc, Raleigh, NC). Each specimen was tested under four different conditions: Intact, Complete Tear with LUCL, RCL and capsule tear, LUCL/RCL reconstruction + capsule repair and LUCL/RCL reconstruction only. Reconstruction was performed according to the docking technique (Jones, JSES, 2013) and the capsule was repaired with mattress sutures. Each condition was tested in 30°, 60° and 90° elbow flexion. A two-way ANOVA with Tukey's post-hoc test was used to detect statistical differences between the conditions. Total ROM of the forearm significantly increased in all flexion angles from intact to Complete tear (p<0.001). ROM was restored to normal in 30° and 60° elbow flexion in both reconstruction conditions (p>0.05). LUCL/RCL Reconstruction + capsule repair in 90° elbow flexion was associated with a significantly lower ROM compared to intact (p=0.0003) and reconstruction without capsule repair (p=0.015). Varus angle increased significantly from intact to complete tear (p<0.0001) and restored to normal in both reconstruction conditions (p>0.05) in 30° and 60° elbow flexion. In contrast varus angle was significantly lower in 90° elbow flexion in both reconstruction conditions compared to intact (both p<0.0001). Reconstruction of the lateral collateral complex restores elbow stability, ROM and varus laxity independent of capsular repair. Over tightening of the elbow joint occurred in 90° elbow flexion, which was aggravated by capsular repair. Over all capsular repair can be performed without negatively affecting elbow joint mobility

Summary. In contrast to the current literature, myofibroblasts are not present in chronic posttraumatic elbow contractures. However, myofibroblasts are present in the acute phase after an elbow fracture and/or dislocation. This suggests a physiological role in normal capsule healing and a potential role in the early phase of posttraumatic contracture formation. Introduction. Elbow stiffness is a common complication after elbow trauma. The elbow capsule is often thickened, fibrotic and contracted upon surgical release. The limited studies available suggest that the capsule is contracted because of fibroblast to myofibroblast differentiation. However, the timeline is controversial and data on human capsules are scarce. We hypothesise that myofibroblasts are absent in normal capsules and early after acute trauma and elevated in patients with posttraumatic elbow contracture. Patients & Methods. We obtained twenty-one human elbow joint capsules within fourteen days after an elbow fracture and/or dislocation and thirty-four capsules from thirty-four patients who had operative release of posttraumatic contractures greater than five months after injury. Myofibroblasts in the joint capsules were quantified using immunohistochemistry. Alpha-smooth muscle actin (α-SMA) was used as a marker for myofibroblasts. Samples were characterised and scored by an independent pathologist blinded for clinical data. Results. Eleven capsules were associated with the acute phase after trauma (hours to 7 days), and staining for α-SMA was negative in all eleven specimens. Ten specimens were associated with a later phase post trauma with myofibroblasts staining positive for α-SMA in all but two. All, but two, thirty-four long standing contractures showed a histological pattern consistent with chronic stages of fibrosis, characterised by increased fibroblast-like cell proliferation and higher cellular density of fibroblast-like cells with highly unstructured collagen. There was no staining of α-SMA in fibroblast-like cells in, all but two of these longstanding contractures suggesting absence of myofibroblasts. Conclusions. This study present ‘negative results’ on the hypothesis that myofibroblast numbers are elevated in longstanding (> 5 months) human posttraumatic elbow capsules. This is in contrast to all studies on human tissue in the literature to date. One recent animal study is in agreement withy our data. We did find some myofibroblasts in elbow capsules in the late-phase posttrauma (between 7 and 14 days) suggesting a potential role in early phase of posttraumatic contracture formation

In order to determine the potential for an internervous safe zone, 20 hips from human cadavers were dissected to map out the precise pattern of innervation of the hip capsule. The results were illustrated in the form of a clock face. The reference point for measurement was the inferior acetabular notch, representing six o’clock. Capsular branches from between five and seven nerves contributed to each hip joint, and were found to innervate the capsule in a relatively constant pattern. An internervous safe zone was identified anterosuperiorly in an arc of 45° between the positions of one o’clock and half past two. Our study shows that there is an internervous zone that could be safely used in a capsule-retaining anterior, anterolateral or lateral approach to the hip, or during portal placement in hip arthroscopy

Background. Hyperlaxity is associated with a high incidence of shoulder dislocations. Collagen V regulates the diameter of fibrils of the abundant collagen type I. Decorin and biglycan are members of the small leucine rich proteoglycans(SLRP's)family and play important roles in the regulation of collagen fibrillogenesis. The aim of this study was to identify if there was a link in hyperlaxity, capsule strength, collagen V and SLRP's expression. Methods. Data was collected for 10 patients undergoing open shoulder stabilization for recurrent instability. Beighton score was used to assess hyperlaxity. Localization of Collagen V and SLRP's was studied by immunohistochemical staining of paraffin embedded sections of shoulder capsule. Grading of the stain was done on a 0-4 scale(0=no staining and 4=strong staining>50% of the slide)by three observers. Shoulder capsules were mounted on a material testing system and vertical load was applied to reach yield. Results. The mean force required for yield in 15 shoulder capsules was 45N(17-78). Data was analysed for Group A(weak group) with yield<45N(8 specimens) and Group B(strong group)with yield>45N(7 specimens). The mean age was 26 years and all were male. The mean force for group A was 31N(17-41) and group B was 59N(45-78). The mean Beighton score for group A was 1.9(0-4) and Group B was 2. 2 specimens in Group A had Beighton score>4 as compared to 0 in Group B, indicating hyperlaxity. The mean grading of collagen V expression in synovial surface was 2.6,Blood vessels(BV)1.6 and extracellular matrix(ECM)1.9 in Group A and 4,3.1 and 2.6 respectively in group B. The mean grading of decorin expression for shoulder capsule was 2.7 in Group A and 3.3 in group B. The mean grading of Biglycan expression in synovial surface was 2,BV 2 and ECM 2.9 in Group A and 2,2.5 and 4 respectively in group B. Conclusions. We found that weaker capsule specimen(group A)had higher incidence of hyperlaxity. Decorin and biglycan expression in ECM and Collagen V expression in synovial surface, BV and ECM of shoulder capsule was higher in group B(strong group). This study shows a link between hyperlaxity, strength, Collagen V and SLRP's expression in shoulder capsule

The Masquelet technique is a variable method for treating critical-sized bone defects, but there is a need to develop a technique for promoting bone regeneration. In recent studies of bone fracture healing promotion, macrophage-mesenchymal stem cell (MSC) cross-talk has drawn attention. This study aimed to investigate macrophage expression in the induced membrane (IM) of the Masquelet technique using a mouse critical-sized bone defect model. The study involved a 3-mm bone defect created in the femur of mice and fixed with a mouse locking plate. The Masquelet (M) group, in which a spacer was inserted, and the Control (C) group, in which the defect was left intact, were established. Additionally, a spacer was inserted under the fascia of the back (B group) to form a membrane due to the foreign body reaction. Tissues were collected at 1, 2, and 4 weeks after surgery (n=5 in each group), and immunostaining (CD68, CD163: M1, M2 macrophage markers) and RT-qPCR were performed to investigate macrophage localization and expression in the tissues. The study found that CD68-positive cells were present in the IM of the M group at all weeks, and RT-qPCR showed the highest CD68 expression at 1 week. In addition, there was similar localization and expression of CD163. The C group showed lower expression of CD68 and CD163 than the M group at all weeks. The B group exhibited CD68-positive cells in the fibrous capsule and CD163-positive cells in the connective tissue outside the capsule, with lower expression of both markers compared to the M group at all weeks. Macrophage expression in IM in M group had different characteristics compared to C group and B group. These results suggest that the IM differs from the fibrous capsules due to the foreign body reaction, and the macrophage-MSC cross-talk may be involved in Masquelet technique

The aim of this work was to develop a novel, accessible and low-cost method, which is sufficient to measure changes in meniscal position in a whole-knee joint model performing dynamic motion in a knee simulator. An optical tracking method using motion markers, MATLAB (MATLAB, The MathWorks Inc.) and a miniature camera system (Raspberry Pi, UK) was developed. Method feasibility was assessed on porcine whole joint knee samples (n = 4) dissected and cemented to be used in the simulator (1). Markers were placed on three regions (medial, posterior, anterior) of the medial meniscus with corresponding reference markers on the tibial plateau, so the relative meniscal position could be calculated. The Leeds high kinematics gait profile scaled to the parameters of a pig (1, 2) was driven in displacement control at 0.5 Hz. Videos were recorded at cycle-3 and cycle-50. Conditions tested were the capsule retained (intact), capsule removed and a medial posterior root tear. Mean relative displacement values were taken at time-points relating to the peaks of the axial force and flexion-extension gait inputs, as well as the range between the maximum and minimum values. A one-way ANOVA followed by Tukey post hoc analysis were used to assess differences (p = 0.05). The method was able to measure relative meniscal displacement for all three meniscal regions. The medial region showed the greatest difference between the conditions. A significant increase (p < 0.05) for the root tear condition was found at 0.28s and 0.90s (axial load peaks) during cycle-3. Mean relative displacement for the root tear condition decreased by 0.29 mm between cycle-3 and cycle-50 at the 0.28s time-point. No statistically significant differences were found when ranges were compared at cycle-3 and cycle-50. The method was sensitive to measure a substantial difference in medial-lateral relative displacement between an intact and a torn state. Meniscus extrusion was detected for the root tear condition throughout test duration. Further work will progress onto human specimens and apply an intervention condition

Abstract. OBJECTIVES. Although surgical periacetabular osteotomy (PAO) for hip dysplasia aims to optimise acetabular coverage and restore hip function, it is unclear how surgery affects capsular mechanics and joint stability. The purpose was to examine how the reoriented acetabular coverage affects capsular mechanics and joint stability in dysplastic hips. METHODS. Twelve cadaveric dysplastic hips (n = 12) were denuded to the capsule and mounted onto a robotic tester. The robot positioned each hip in multiple flexion angles (Extension, Neutral 0°, Flexion 30°, Flexion 60°, Flexion 90°) and performed internal-external rotations and abduction-adduction to 5 Nm in each rotational or planar direction. Each hip underwent a PAO, preserving the capsule, and was retested postoperatively in the robot. Paired sample t-tests compared the range of motion before and after PAO surgery (CI = 95%). RESULTS. Pre-operatively, the dysplastic hips demonstrated large ranges of internal-external rotations and abduction-adduction motions throughout all flexion positions. Post-operatively, the PAO slackenend the anterosuperior capsule and tightened the inferior capsule. This increased external rotation in Flexion 60° and Flexion 90° (∆. ER. = +16 and +23%) but provided lateral coverage to decrease internal rotation at Flexion 90° (∆. IR. = –15%). The PAO also reduced abduction throughout, but increased adduction in Neutral 0°, Flexion 30°, and Flexion 60° (∆. ADD. = +34, +30%, +29% respectively). CONCLUSIONS. The PAO provided crucial osseous structural coverage to the femoral head, decreasing hypermobility and adverse loading at extreme hip flexion-extension. However, it also slackened the anterosuperior capsule and increased adduction and external rotation, which may lead to ischiofemoral impingement and adductor irritations. Capsular instability may be secondary to acetabular undercoverage, thus capsular alteration may be warranted for larger corrections or rotational osteotomies. To preserve native hip and delay joint degeneration, it is crucial to preserve capsule and elucidate amount of reorientation needed without causing iatrogenic instability. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Introduction and Objective. The human body is designed to walk in an efficient way. As energy can be stored in elastic structures, it is no surprise that the strongest elastic structure of the human body, the iliofemoral ligament (IFL), is located in the lower limb. Numerous popular surgical hip interventions, however, affect the structural integrity of the hip capsule and there is a growing evidence that surgical repair of the capsule improves the surgical outcome. Though, the exact contribution of the iliofemoral ligament in energy efficient hip function remains unelucidated. Therefore, the objective of this study was to evaluate the influence of the IFL on energy efficient ambulation. Materials and Methods. In order to assess the potential passive contribution of the IFL to energy efficient ambulation, we simulated walking using the large public dataset (n=50) from Schreiber in a the AnyBody musculoskeletal modeling environment with and without the inclusion of the IFL. The work required from the psoas, iliacus, sartorius, quadriceps and gluteal muscles was evaluated in both situations. Considering the large uncertainty on ligament properties a parameter study was included. Results. A significant reduction in the active component of all hip flexors was observed when the IFL is intact. The required muscle work was found to be reduced by as much as 48% (CI: 29–62%), 61% (CI: 35–84%) and 38% (CI: 2–69%) for the psoas, iliacus, and sartorius muscle respectively. The IFL inclusion has no major effect on the required work from the quadriceps and the gluteal muscle group. The energy storage in the IFL is largest at maximal hip extension and the contribution to forward motion is the largest at the start of the swing phase. Conclusions. The iliofemoral ligament seems to be a crucial structure in energy efficient walking. The findings support need for meticulous reconstruction of the capsule ligament in case of surgical damage

Several studies have evaluated the risk of peroneal nerve (PN) injuries in all-inside lateral meniscal repair using standard knee magnetic resonance imaging (MRI) with the 30 degrees flexed knee position which is different from the knee position during actual arthroscopic lateral meniscal repair. The point of concern is “Can the risk of PN injury using standard knee MRIs be accurately determined”. To evaluate and compare the risk of PN injury in all-inside lateral meniscal repair in relation to both borders of the popliteus tendon (PT) using MRIs of the two knee positions in the same patients. Using axial MRI studies with standard knee MRIs and figure-of-4 with joint fluid dilatation actual arthroscopic lateral meniscal repair position MRIs, direct lines were drawn simulating a straight all-inside meniscal repair device from the anteromedial and anterolateral portals to the medial and lateral borders of the PT. The distance from the tip of each line to the PN was measured. If a line touched or passed the PN, a potential risk of iatrogenic injury was noted and a new line was drawn from the same portal to the border of the PN. The danger area was measured from the first line to the new direct line along the joint capsule. In 28 adult patients, the closest distances from each line to the PN in standard knee MRI images were significantly shorter than arthroscopic position MRI images (all p-values < 0.05). All danger areas assessed in the actual arthroscopic position MRIs were included within the danger areas as assessed by the standard knee MRIs. We found that the standard knee MRIs can be used to determine the risk of peroneal nerve injury in arthroscopic lateral meniscal repair, although the risks are slightly overestimated

Hip joint biomechanics can be altered by abnormal morphology of the acetabulum and/or femur. This may affect load distribution and contact stresses on the articular surfaces, hence, leading to damage and degradation of the tissue. Experimental hip joint simulators have been used to assess tribology of total hip replacements and recently methods further developed to assess the natural hip joint mechanics. The aim of this study was to evaluate articular surfaces of human cadaveric joints following prolonged experimental simulation under a standard gait cycle. Four cadaveric male right hips (mean age = 62 years) were dissected, the joint disarticulated and capsule removed. The acetabulum and femoral head were mounted in an anatomical hip simulator (Simulation Solutions, UK). A simplified twin peak gait cycle (peak load of 3kN) was applied. Hips were submerged in Ringers solution (0.04% sodium azide) and testing conducted at 1 Hertz for 32 hours (115,200 cycles). Soft tissue degradation was recorded using photogrammetry at intervals throughout testing. All four hips were successfully tested. Prior to simulation, two samples exhibited articular surface degradation and one had a minor scalpel cut and a small area of cartilage delamination. The pre-simulation damage got slightly worse as the simulation continued but no new areas of damage were detected upon inspection. The samples without surface degradation, showed no damage during testing and the labral sealing effect was more obvious in these samples. The fact that no new areas of damage were detected after long simulations, indicates that the loading conditions and positioning of the sample were appropriate, so the simulation can be used as a control to compare mechanical degradation of the natural hip when provoked abnormal conditions or labral tissue repairs are simulated

For chondral damage in younger patients, surgical best practice is microfracture, which involves drilling into the bone to liberate the bone marrow. This leads to a mechanically inferior fibrocartilage formed over the defect as opposed to the desired hyaline cartilage that properly withstands joint loading. While some devices have been developed to aid microfracture and enable its use in larger defects, fibrocartilage is still produced and there is no clear clinical improvement over microfracture alone in the long term. Our goal is to develop 3D printed devices, which surgeons can implant with a minimally invasive technique. The scaffolds should match the functional properties of cartilage and expose endogenous marrow cells to suitable mechanobiological stimuli in-situ, in order to promote healing of articular cartilage lesions before they progress to osteoarthritis, and rapidly restore joint health and mobility. Importantly, scaffolds should direct a physiological host reaction, instead of a foreign body reaction, associated with chronic inflammation and fibrous capsule formation, negatively influencing the regenerative outcome. Our novel silica/polytetrahydrofuran/polycaprolactone hybrids were prepared by sol-gel synthesis and scaffolds were 3D printed by direct ink writing. 3D printed hybrid scaffolds with pore channels of ~250 µm mimic the compressive behaviour of cartilage. Our results show that these scaffolds support human bone marrow stem/stromal cell (hMSC) differentiation towards chondrogenesis in vitro under hypoxic conditions to produce markers integral to articular cartilage-like matrix evaluated by immunostaining and gene expression analysis. Macroscopic and microscopic evaluation of subcutaneously implanted scaffolds in mice showed that scaffolds caused a minimal resolving inflammatory response. Our findings show that 3D printed hybrid scaffolds have the potential to support cartilage regeneration. Acknowledgements: Authors acknowledge funding provided by EPSRC grant EP/N025059/1

Introduction. Supraspinatus and infraspinatus tears (Massive Rotator Cuff Tear- MRCT) cause compensatory activation of the teres minor (TM) and subscapularis (SubS) to maintain humeral head alignment. This study measures force changes in TM and SubS using a dynamic shoulder testing setup. We hypothesize that combining superior capsule reconstruction (SCR) and lower trapezius tendon (LTT) transfer will correct rotator cuff forces. Methods. Eight fresh-frozen human shoulder specimens from donors aged 55-75 (mean = 63.75 years), balanced for gender, averaging 219.5 lbs, were used. Rotator cuff and deltoid tendons were connected to force sensors through a pulley system, with the deltoid linked to a servohydraulic motor for dynamic force measurement. The system allowed unrestricted humeral abduction from 0 to 90 degrees. Results. Teres Minor (TM):. -. Control: 7.43 N (SD = 1.66). -. SS tear: 5.46 N (SD = 1.45). -. MRCT: 3.94 N (SD = 1.43). -. LTT post-MRCT: 5.85 N (SD = 1.13). -. SCR post-MRCT: 4.68 N (SD = 0.71). -. Combined LTT+SCR: 6.43 N (SD = 1.24). -. TM force reduction: 26.51% post-SS tear, 46.97% from intact to MRCT, 63.20% increase with LTT+SCR. Subscapularis (SubS):. -. Control: -0.73 N (SD = 0.43). -. SS tear: -0.46 N (SD = 0.36), 36.99% increase. -. MRCT: 0.96 N (SD = 0.47), 31.51% increase. -. LTT post-MRCT: -0.32 N (SD = 0.47), 66.67% reduction. -. SCR post-MRCT: -0.28 N (SD = 0.16), 70.83% reduction. -. Combined LTT+SCR: -0.66 N (SD = 0.32), 31.25% reduction. Non-parametric Friedman's ANOVA showed overall statistical significance for TM (P = 1.083×10. -6. ) and SubS (P = 4.77×10. -4. ). Conclusion. The cadaveric model assesses rotator cuff compensations, showing significant TM force reductions following rotator cuff tears and improvements with LTT and SCR, particularly when combined. SubS exhibited negative force during normal abduction but compensated during MRCT, returning to normal values post-LTT and SCR

Introduction and Objective. Objectives: To determine the effectiveness of LIA compared to ACB in providing pain relief and reducing opiates usage in hamstring graft ACL reconstructions. Materials and Methods. In a consecutive series of hamstring graft ACL reconstructions, patients received three different regional and/or anaesthetic techniques for pain relief. Three groups were studied: group 1: general anaesthetic (GA)+ ACB (n=38); group 2: GA + ACB + LIA (n=31) and group 3: GA+LIA (n=36). ACB was given under ultrasound guidance. LIA involved infiltration at skin incision site, capsule, periosteum and in the hamstring harvest tunnel. Analgesic medications were similar between the three groups as per standard multimodal analgesia (MMA). Patients were similar in demographics distribution and surgical technique. The postoperative pain and total morphine requirements were evaluated and recorded. The postoperative pain was assessed using the visual analogue scores (VAS) at 0hrs, 2hrs, 4hrs, weight bearing (WB) and discharge (DC). Results. There was no statistically significant difference in opiates intake amongst the three groups. When comparing VAS scores; there were no statistical difference between the groups at any of the time intervals that VAS was measured. However, the GA+LIA group hospital's LOS (m=2.31hrs, SD=0.75) was almost half that of GA+ACB group (m=4.24hrs, SD=1.08); (conditions t(72)=8.88; p=0.000). There was no statistical significance in the incidence of adverse effects amongst the groups. Conclusions. The LIA technique provided equally good pain relief following hamstring graft ACL reconstructions when compared to ACB, while allowing for earlier rehabilitation, mobilisation and discharge

Aims. Animal models have been developed that allow simulation of post-traumatic joint contracture. One such model involves contracture-forming surgery followed by surgical capsular release. This model allows testing of antifibrotic agents, such as rosiglitazone. Methods. A total of 20 rabbits underwent contracture-forming surgery. Eight weeks later, the animals underwent a surgical capsular release. Ten animals received rosiglitazone (intramuscular initially, then orally). The animals were sacrificed following 16 weeks of free cage mobilisation. The joints were tested biomechanically, and the posterior capsule was assessed histologically and via genetic microarray analysis. Results. There was no significant difference in post-traumatic contracture between the rosiglitazone and control groups (33° (standard deviation (. sd. ) 11) vs 37° (. sd. 14), respectively; p = 0.4). There was no difference in number or percentage of myofibroblasts. Importantly, there were ten genes and 17 pathways that were significantly modulated by rosiglitazone in the posterior capsule. Discussion. Rosiglitazone significantly altered the genetic expression of the posterior capsular tissue in a rabbit model, with ten genes and 17 pathways demonstrating significant modulation. However, there was no significant effect on biomechanical or histological properties. Cite this article: M. P. Abdel. Effectiveness of rosiglitazone in reducing flexion contracture in a rabbit model of arthrofibrosis with surgical capsular release: A biomechanical, histological, and genetic analysis. Bone Joint Res 2016;5:11–17. doi: 10.1302/2046-3758.51.2000593

Summary. Previous work in a rabbit model of post-traumatic joint contractures shows that the mast cell stabilizer ketotifen decreases contracture severity. We show here that ketotifen decreases collagen gel contraction mediated by rabbit joint capsule fibroblasts when mast cells are present. Introduction. Ketotifen was shown to decrease contracture severity and associated joint capsule fibrosis in an animal model of post-traumatic joint contractures. Ketotifen prevents the release of profibrotic growth factors from mast cells (MC). An in vitro collagen gel contraction assay is used to examine the effect of ketotifen on joint capsule fibroblasts obtained from this animal model. Methods. Six New Zealand White rabbits had a standardised procedure to induce post-traumatic joint contractures and the joint capsule was harvested 4 weeks later. The capsules were minced, placed into T75 culture flasks and incubated at 37. 0. C in a humidified atmosphere containing 5% CO. 2. The Joint Capsule fibroblasts (JC, 2.5 × 10. 5. cells/mL) were mixed with neutralised collagen solution composed of 59% neutralised PureCol collagen I, serum free DMEM/F12 with 1x serum replacement and 1x antibiotic-antimycotic. Aliquots of solution were then cast into wells of a tissue culture plate. Gelation occurred over 3h at 37°C in a humidified incubator. The collagen gel/cells were maintained with DMEM/F-12 plus 1% serum replacement and 1% antibiotic-antimycotic and incubated at 37°C for 12 h. The gels were released and gel area was calculated up to 72h post-release. Different experiments were conducted with various combinations of a human mast cell line (HMC-1, 7.5 × 10. 5. cells/mL), the neuropeptide Substance P (SP, 10. −6. M) and Ketotifen fumurate at 10. −4. , 10. −6. , 10. −8. and 10. −10. M. The various interventions were combined with the JC and collagen gel during the gelation step. Statistical comparisons used a two way ANOVA with a Posthoc Tukey test. Significance was set at p < 0.05. Results. The JC contracted the collagen gels in all conditions, with statistically significant differences between time intervals from 6 h to 72 h. When ketotifen alone was added to JC, there was no effect on collagen gel contraction in the range of doses tested. Adding MC to JC led to a significantly increased rate of gel contraction that was inhibited by ketotifen in a dose-dependent manner. The effect was maximal with a concentration of 10. −4. M while the effect was absent by the dose of 10. −10. M. There were statistically significant differences amongst different doses except for comparisons between doses closest to each other (10. −4. vs 10. −6. , 10. −6. vs 10. −8. , 10. −8. vs 10. −10. M). Including SP with MC and JC further increased the rate of gel contraction, which was also significantly inhibited by ketotifen in a similar dose-dependent fashion. Discussion/Conclusion. Fibroblasts from rabbit joint capsules contract collagen gels with the effect enhanced by the addition of mast cells. Ketotifen prevents the release of mediators by mast cells, and ketotifen modified the collagen gel assay. It appears that the inhibition of the gel contraction by the fibroblasts is via mast cell stabilization since ketotifen had no direct affect on the fibroblasts in the concentrations evaluated. Ketotifen is a medication used in the chronic treatment of asthma. It has a wide safety profile, it is already approved for human use and it is available in oral preparations

Abstract. Objective. The aim of our systematic review was to report the latest evidence on the effects of CoCr particles on local soft tissue with a focus on its clinical relevance. Methods. PubMed, Embase, and Cochrane Library databases were screened to perform an extensive review. Inclusion criteria were studies of any level of evidence published in peer-reviewed journals reporting clinical and preclinical results written in English. Relative data were extracted and critically analyzed. PRISMA guidelines were applied, and the risk of bias was assessed, as was the methodological quality of the included studies. Results. 30 studies were included after applying the inclusion and exclusion criteria. Of these, 24 were preclinical studies (18 in vitro human studies, 6 animal modal studies, including 3 in vitro and 3 in vivo), 5 were clinical studies and 1 was previous review on similar topic. The presence of metal ions causes cell damage by reducing cell viability, inducing DNA damage, and triggering the secretion of cytokines. Mechanisms of apoptosis, autophagy and necrosis are responsible for the inflammatory reaction observed in ALTR. Conclusion. The available literature on the effects of CoCr particles released from MoM implants shows that metal debris can cause damage to skeletal muscle, the capsule, and provoke osteolysis and inflammation. Therefore, the cytotoxic and genotoxic damages, as well as the interaction with the immune system, affect the success of the arthroplasty and lead to a higher rate of revision surgeries. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Invasive intraneural electrodes implanted in peripheral nerves are neural prosthetic devices that are exploied to control advanced neural-interfaced prostheses in human amputees. One of the main issues to be faced in chronic implants is represented by the gradual loss of functionality of such intraneural interfaces due to an electrical impedance increase caused by the progressive formation of a fibrotic capsule around the electrodes, which is originally due to a nonspecific inflammatory response called foreign body reaction (FBR). In this in vitro work, we tested the biocompatibility and ultra-low fouling features of the synthetic coating - poly(ethylene glycol) (PEG) - compared to the organic polymer - zwitterionic sulfated poly(sulfobetaine methacrylate) (SBMA) hydrogel - to prevent or reduce the first steps of the FBR: plasma protein adsorption and cell adhesion to the interface. Synthesis and characterization of the SBMA hydrogel was done. Preliminary biocompatibility analysis of the zwitterionic hydrogel, using hydrogel-conditioned medium, showed no cytotoxicity at all vs. control. We seeded GFP-labelled human myofibroblasts on PEG- and SBMA hydrogel-coated polyimide surfaces and evaluated their adhesion and cell viability at different time-points. Because of the high hydration, low stiffness reflecting the one of neural tissue, and ultra-low fouling characteristics of the SBMA hydrogel, this polymer showed lower myofibroblast adhesion and different cell morphology compared to adhesion controls, thereby representing a better coating than PEG for potentially mitigating the FBR. We conclude that soft SBMA hydrogels could outperform PEG coatings in vitro as more suitable dressings of intraneural electrodes. Furthermore, such SBMA-based antifouling materials can be envisioned as long-term diffusion-based delivery systems for controlled release of anti-inflammatory and anti-fibrotic drugs in vivo

Abstract. OBJECTIVES. Cam femoroacetabular impingement (FAI – femoral head-neck deformity) and developmental dysplasia of the hip (DDH – insufficient acetabular coverage) constitute a large portion of adverse hip loading and early degeneration. Spinopelvic anatomy may play a role in hip stability thus we examined which anatomical relationships can best predict range of motion (ROM). METHODS. Twenty-four cadaveric hips with cam FAI or DDH (12:12) were CT imaged and measured for multiple femoral (alpha angles, head-neck offset, neck angles, version), acetabular (centre-edge angle, inclination, version), and spinopelvic features (pelvic incidence). The hips were denuded to the capsule and mounted onto a robotic tester. The robot positioned each hip in multiple flexion angles (Extension, Neutral 0°, Flexion 30°, Flexion 60°, Flexion 90°); and performed internal-external rotations to 5 Nm in each position. Independent t-tests compared the anatomical parameters and ROM between FAI and DDH (CI = 95%). Multiple linear regressions determined which anatomical parameters could predict ROM. RESULTS. The FAI group demonstrated restricted ROM in deep hip flexion, with DDH showing higher ROM in Flexion 30° (+20%, p = 0.03), 60° (+31%, p = 0.001), and 90° (+36%, p = 0.001). In Neutral 0° and Flexion 30°, femoral neck and version angles together predicted ROM (R. 2. = 60%, 58% respectively); whereas in Flexion 60°, pelvic incidence and femoral neck angle predicted ROM (R. 2. = 77%). In Flexion 90°, pelvic incidence and radial alpha angle together predicted ROM (R. 2. = 81%), where pelvic incidence alone accounted for 63% of this variance. CONCLUSIONS. Pelvic incidence is essential to predict hip ROM. Although a cam deformity or acetabular undercoverage can elevate risks of labral tears and progressive joint degeneration, they may not be primary indicators of restrictive hip impingement or dysplastic instability. Better delineating additional spinopelvic characteristics can formulate early diagnostic tools and improve opportunities for nonsurgical management. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Poor soft tissue balance in total knee arthroplasty (TKA) is one of the most primary causes of dissatisfaction and reduced joint longevity, which are associated with postoperative instability and early implant failure. 1. Therefore, surgical techniques, including mechanical instruments and 3-D guided navigation systems, in TKA aim to achieve optimum soft tissue balancing in the knee to improve postoperative outcome. 2. Patella-in-Place balancing (PIPB) is a novel technique which aims to restore native collateral ligament behaviour by preserving the original state without any release. Moreover, reduction of the joint laxity compensates for the loss of the visco-elastic properties of the cartilage and meniscus. Following its clinical success, we aimed to evaluate the impact of the PIPB technique on collateral ligament strain and laxity behaviour, with the hypothesis that PIPB would restore strains in the collateral ligaments. 3. . Eight fresh-frozen cadaveric legs were obtained (KU Leuven, Belgium, H019 2015-11-04) and CT images were acquired while rigid marker frames were affixed into the femur, and tibia for testing. After carefully removing the soft tissues around the knee joint, while preserving the joint capsule, ligaments, and tendons, digital extensometers (MTS, Minnesota, USA) were attached along the length of the superficial medial collateral ligament (MCL) and lateral collateral ligament (LCL). A handheld digital dynamometer (Mark-10, Copiague, USA) was used to apply an abduction or adduction moment of 10 Nm at fixed knee flexion angles of 0°, 30°, 60° and 90°. A motion capture system (Vicon Motion Systems, UK) was used to record the trajectories of the rigid marker frames while synchronized strain data was collected for MCL/LCL. All motion protocols were applied following TKA was performed using PIPB with a cruciate retaining implant (Stryker Triathlon, MI, USA). Furthermore, tibiofemoral kinematics were calculated. 4. and combined with the strain data. Postoperative tibial varus/valgus stresses and collateral ligament strains were compared to the native condition using the Wilcoxon Signed-Rank Test (p<0.05). Postoperative tibial valgus laxity was lower than the native condition for all flexion angles. Moreover, tibial valgus of TKA was significantly different than the native condition, except for 0° (p=0.32). Although, tibial varus laxity of TKA was lower than the native at all angles, significant difference was only found at 0° (p=0.03) and 90° (p=0.02). No significant differences were observed in postoperative collateral ligament strains, as compared to the native condition, for all flexion angles, except for MCL strain at 30° (p=0.02) and 60° (p=0.01). Results from this experimental study supported our hypotheses, barring MCL strain in mid-flexion, which might be associated with the implant design. Restored collateral ligament strains with reduced joint laxity, demonstrated by the PIPB technique in TKA in vitro, could potentially restore natural joint kinematics, thereby improving patient outcomes. In conclusion, to further prove the success of PIPB, further biomechanical studies are required to evaluate the success rate of PIPB technique in different implant designs