Outcome of reverse shoulder arthroplasty secondary to rotator cuff arthropathy in a low-income population.

BACKGROUND: Reverse shoulder arthroplasty (RSA) is a valuable treatment for rotator cuff arthropathy (RCA) in developed regions. Socioeconomic issues impact access to specialized care and there is a lack of data on RSA outcomes in developing regions. We present our 24-month follow-up on RSA surgeries to treat RCA in our low-income population. METHODS: Prospective evaluation of 26 patients subjected to RSA at Hospital Geral de Fortaleza-CE, Brazil, between January 2018 and December 2020. Literacy [>/≤ 8 school years(SY)] and income were documented. Outcomes considered pain (visual analogue scale; VAS) as well as SSV, SPADI, ASES, and UCLA scoring, and range of motion [forward flexion (FF); external rotation (ER)]. RESULTS: Patients were 68.5 ± 7.6 years-old with 16(61.5%) females; 65% had hypertension and 7 (26.9%) had diabetes. Over 90% declared < 900.00 US$ monthly family earnings and 10 (38.4%) patients declared ≤8 SY with > 80% exerting blue-collar jobs. Pain showed a significant reduction from baseline (8 ± 2) to 24 months (2.1 ± 2.3; p < 0.001). UCLA (10.3 ± 5.6 and 28.6 ± 7.2), ASES (16.7 ± 10.8 and 63.1 ± 28.4), SSV (326 ± 311 and 760 ± 234), and SPADI (98.3 ± 26.5) scores significantly improved from baseline to 24 months, achieving minimal clinically important difference. FF (89.2° ± 51.2° to 140.6 ± 38.3°) and ER (19.2° ± 22.5 to 33.4° ± 20.6°) significantly improved from baseline to 24 months (p = 0.004 and 0.027, respectively). There were 5 non-serious adverse events with one surgical revision. All patients returned to daily life activities. CONCLUSION: This is the first outcome report 2 years following RSA in a low-income population. Data indicate this procedure is justifiable regardless of socioeconomic issues.

Surgical outcome following rotator cuff tear repair in a low-income population. Impact of obesity and smoking.

BACKGROUND: Comorbidities and socioeconomic issues impact outcome of rotator cuff tear (RCT) repair. There are no data on RCT repair outcome from developing regions. We determined the impact of obesity and smoking following RCT repair in a low-income population. METHODS: This is a retrospective case series. Forty-seven shoulders of 42 patients subjected to open or arthroscopic repair of a RCT with a minimum of 2 years follow-up were cross-sectionally evaluated. Patients were seen in the Orthopaedic Service of the Hospital Geral de Fortaleza-CE, Brazil between March and September 2018. RCT were classified as partial or full-thickness lesions. Fatty infiltration (Goutallier) and tendon retraction (Patte) were recorded as well as obesity (BMI > 30), literacy [>/≤ 8 school years (SY)] and smoking status 6 months prior to surgery (present/absent). Outcomes included pain (visual analogue scale; VAS, 0-10 cm), range of motion [active forward flexion and external rotation (ER)], UCLA and ASES scoring. RESULTS: Patients were 59.9 ± 7.4 years-old, 35(74.4%) female with 19 (17.1-30.2 IQR) median of months from diagnosis to surgery and 25 median months of follow-up (26.9-34.0 IQR); over 90% declared < 900.00 US$ monthly family income and two-thirds had ≤8 SY. Forty patients (85.1%) had full-thickness tears, 7 (14.9%) had Goutallier ≥3 and over 80% had < Patte III stage. Outcomes were similar regardless of fatty infiltration or tendon retraction staging. There were 17 (36.1%) smokers and 13 (27.6%) obese patients. Outcome was similar when comparing obese vs non-obese patients. Smokers had more pain (P = 0.043) and less ER (P = 0.029) with a trend towards worse UCLA and ASES scores as compared to non-smokers though differences did not achieve minimal clinically important difference (MCID) proposed for surgical RCT treatment. After adjusting for obesity, VAS and ER values in smokers were no longer significant (P = 0.2474 and 0.4872, respectively). CONCLUSIONS: Our data document outcomes following RCT repair in a low-income population. Smoking status but not obesity impacted RCT repair outcome though not reaching MCID for surgical treatment.

Polysaccharides As Viscosupplementation Agents: Structural Molecular Characteristics but Not Rheology Appear Crucial to the Therapeutic Response.

INTRODUCTION: Most clinical studies and basic research document viscosupplementation (VS) in terms of effectiveness and safety, but only a few highlight its molecular mechanisms of action. Besides, there is generally focus on hyaluronic acid (HA) as being the most relevant polysaccharide to reach the clinical endpoints, attributing its effect mainly to its unique viscoelastic properties, related to a high-molecular weight and gel formulation. Usually, studies do not approach the possible biological pathways where HA may interfere, and there is a lack of reports on other biocompatible polysaccharides that could be of use in VS. AIM: We briefly review the main proposed mechanisms of action of intra-articular hyaluronic acid (IA-HA) treatment and discuss its effectiveness focusing on the role of rheological and intrinsic structural molecular properties of polysaccharides in providing a therapeutic effect. METHODS: We conducted a literature search using PubMed database to find articles dealing with the mechanisms of action of IA-HA treatment and/or emphasizing how the structural properties of the polysaccharide used influenced the clinical outcomes. DISCUSSION/CONCLUSION: HA is involved in numerous biochemical interactions that may explain the clinical benefits of VS, most of them resulting from HA-cluster of differentiation 44 receptor interaction. There are other important aspects apart from the molecular size or the colloidal state of the IA-HA involved in VS efficiency that still need to be consolidated. Indeed, it seems that clinical response may be dependent on the intrinsic properties of the polysaccharide, regardless of being HA, rather than to rheology, posing some controversy to previous beliefs.

Structural characteristics are crucial to the benefits of guar gum in experimental osteoarthritis.

Protein-free guar gum (DGG) was oxidized (DGGOX) or sulfated (DGGSU) by insertion of new groups in C-6 (manose) and C-6 (galactose), for DGGOX and DGGSU, respectively. Rats were subjected to anterior cruciate ligament transection (ACLT) of the knee, joint pain recorded using the articular incapacitation test, and the analgesic effect of intraarticular 100µg DGG, DGGOX or DGGSU solutions at days 4-7 was evaluated. Other groups received DGG or saline weekly, from days 7 to 70 and joint damage assessed using histology and biochemistry as the chondroitin sulfate (CS) content of cartilage. The molar mass of CS samples was obtained by comparing their relative electrophoretic mobility to standard CS. DGG but not DGGOX or DGGSU significantly inhibited joint pain. DGG significantly reversed the increase in CS, its reduced electrophoretic mobility, and histological changes following ACLT, as compared to vehicle. Structural integrity accounts for DGG benefits in experimental osteoarthritis.

Assessment of zymosan-induced leukocyte influx in a rat model using sulfated polysaccharides.

Fucoidan, a sulfated polysaccharide from the brown algae Fucus vesiculosus, has diverse biological properties, including anti-inflammatory, anticoagulant and antithrombotic activity. This study analyzed the therapeutic activity of total fucoidan (TF) from F. vesiculosus and that of purified fractions (F1 and F2) on zymosan-induced arthritis. Arthritis was induced by injecting zymosan into the knee joint. Thus, three fucoidan fractions were obtained by acetone fractionation. Due to the yield obtained from F3, we used only fucoidans F1 and F2 in the induced inflammation tests. Chemical analyses and electrophoretic characterization of these fractions demonstrated that they contain polysaccharides, sulfate ester and very low protein levels. The fucoidans obtained from TF showed only an electrophoretic band in agarose gel with much lower polydispersion. The F2 fraction showed a migration between fucoidans F1 and F3. We administered TF (15, 30, 50 mg/kg I. P.), F1 or F2 (10, 25 and 50 mg/kg I. P.), diclofenac sodium (10 mg/kg I. P.), lumiracoxib (5 mg/kg O. A.) or L-NAME (30 mg/kg I. P.), 1 hour after induction of articular inflammation. We analyzed cell influx and nitrite levels in addition to performing histopathological analysis. TF (total fucoidan) at 15, 30, 50 mg/kg I. P. and its fractions (F1 and F2 at concentrations of 25 and 50 mg/kg I. P.) significantly reduced cellular influx and nitric oxide concentration. Moreover, the articular inflammation in zymosan-induced arthritis caused a progressive loss in glycosaminoglycan content. This loss decreased when TF (30 mg/kg) was administered. These data suggest that fucoidan exerts anti-inflammatory action in a zymosan-induced model of acute inflammation in rats. Taken together with the fact that these natural compounds have minimal toxicity, this may have important therapeutic implications.

Involvement of LTB4 in zymosan-induced joint nociception in mice: participation of neutrophils and PGE2.

Leukotriene B4 (LTB4) mediates different inflammatory events such as neutrophil migration and pain. The present study addressed the mechanisms of LTB4-mediated joint inflammation-induced hypernociception. It was observed that zymosan-induced articular hypernociception and neutrophil migration were reduced dose-dependently by the pretreatment with MK886 (1-9 mg/kg; LT synthesis inhibitor) as well as in 5-lypoxygenase-deficient mice (5LO(-/-)) or by the selective antagonist of the LTB(4) receptor (CP105696; 3 mg/kg). Histological analysis showed reduced zymosan-induced articular inflammatory damage in 5LO(-/-) mice. The hypernociceptive role of LTB4 was confirmed further by the demonstration that joint injection of LTB4 induces a dose (8.3, 25, and 75 ng)-dependent articular hypernociception. Furthermore, zymosan induced an increase in joint LTB4 production. Investigating the mechanism underlying LTB4 mediation of zymosan-induced hypernociception, LTB4-induced hypernociception was reduced by indomethacin (5 mg/kg), MK886 (3 mg/kg), celecoxib (10 mg/kg), antineutrophil antibody (100 mug, two doses), and fucoidan (20 mg/kg) treatments as well as in 5LO(-/-) mice. The production of LTB4 induced by zymosan in the joint was reduced by the pretreatment with fucoidan or antineutrophil antibody as well as the production of PGE2 induced by LTB4. Therefore, besides reinforcing the role of endogenous LTB4 as an important mediator of inflamed joint hypernociception, these results also suggested that the mechanism of LTB4-induced articular hypernociception depends on prostanoid and neutrophil recruitment. Furthermore, the results also demonstrated clearly that LTB4-induced hypernociception depends on the additional release of endogenous LTs. Concluding, targeting LTB4 synthesis/action might constitute useful therapeutic approaches to inhibit articular inflammatory hypernociception.

Neutrophils-derived peroxynitrite contributes to acute hyperalgesia and cell influx in zymosan arthritis.

We investigated the contribution of neutrophils to joint hyperalgesia and peroxynitrite formation in zymosan arthritis. Rats received 1 mg zymosan intra-articular, and joint hyperalgesia was measured using the rat knee-joint articular incapacitation test. After 6 h, joint exudates were collected by aspiration for the assessment of cell influx, myeloperoxidase activity, and nitrite (as an index of nitric oxide formation) levels. Nitrotyrosine content, used as an index of peroxynitrite formation, was measured in joint exudates, using enzyme-linked immunosorbent assay. A group of rats was rendered neutropenic through the administration of a rabbit anti-rat neutrophil antibody (2 ml kg(-1), i.p.) 30 min before injection of 1 mg zymosan intra-articular. Other groups received uric acid (100 or 250 mg kg(-1), i.p.), the peroxynitrite scavenger, 30 min before 1 mg zymosan intra-articular. Controls received the vehicle. The significant inhibition of joint hyperalgesia in neutropenic animals was associated to significantly decreased cell influx, myeloperoxidase activity, nitric oxide, and nitrotyrosine levels in the joint exudates, as compared to naive rats. Uric acid administration inhibited both hyperalgesia and cell influx, as compared to controls. Neutrophils are involved in both nitric oxide and peroxynitrite formation in zymosan arthritis, thereby contributing to acute joint hyperalgesia. Scavenging of reactive nitrogen species (e.g. peroxynitrite) inhibits neutrophil migration and joint hyperalgesia in the acute phase of zymosan arthritis in rats.

Anti-inflammatory and anti-nociceptive activity of risedronate in experimental pain models in rats and mice.

1. The antinociceptive effect of risedronate in experimental pain models in rats and mice was investigated in the present study. 2. Rats received zymosan intra-articularly (i.art.) into the right knee joint and the nociceptive response was assessed using the articular incapacitation test. Joint washouts were used for determining cell influx, tumour necrosis factor (TNF)-alpha and leukotriene (LT) B4 levels. 3. Mice received either zymosan (1 mg) or acetic acid (0.6%) i.p. and the nociceptive response was measured as the number of writhings between 0 and 30 min after the stimuli. Control animals received i.p. injections of saline. 4. Groups were pretreated with risedronate (5-500 microg/kg, s.c.) and compared with vehicle (saline)-treated (NT) animals. One group of rats was cotreated with the micro-opioid receptor antagonist naloxone (2 mg/kg, s.c.) prior to risedronate, followed by 1 mg zymosan i.art. 5. Risedronate, at 100 and 500 microg/kg, significantly and dose-dependently inhibited the nociceptive response in the writhings test (P < 0.05), inhibiting responses to acetic acid by 65.4 and 49.2%, respectively, and to zymosan by 72.9 and 71.9%, respectively. 6. Pretreatment with risedronate also significantly (P < 0.05) and dose-dependently inhibited the articular incapacitation in zymosan-arthritis. 7. Risedronate, at 50 microg/kg, significantly inhibited TNF-alpha release as compared with the NT group (39.4 +/- 9.8 vs 145.6 +/- 43.3 pg/mL TNF-alpha, respectively). 8. Risedronate, at 50 and 100 microg/kg, significantly inhibited LTB4 release into the joints compared with the NT group (2883.1 +/- 73.2, 1911.5 +/- 205.3 and 4709.9 +/- 237.2 pg/mL, respectively). These effects of risedronate were associated with a significant reduction in the inflammatory cell infiltration. 9. Cotreatment with risedronate and naloxone did not reverse the antinociceptive effects of risedronate in zymosan-arthritis. 10. This is the first demonstration that risedronate displays intrinsic antihypernociceptive activity. This effect is associated with reduced cell infiltration and inhibition of TNF-alpha and LTB4 release and is not linked to an endogenous opioid-release mechanism.

Hypernociception elicited by tibio-tarsal joint flexion in mice: a novel experimental arthritis model for pharmacological screening.

Mice have been used as animal model to study mechanisms underlying inflammatory and immune diseases. The present study describes a model of joint inflammation-induced hypernociception to discriminate pharmacological tests in mice. A polypropylene tip probe with a large area (4.15 mm2) applied on the plantar surface of the hind paw was used to produce a dorsal flexion of tibio-tarsal joint. Experiments were performed to demonstrate that the probe application did not provoke cutaneous nociception. The decrease in the withdrawal threshold of inflamed joint was used as nociceptive parameter. Administration of zymosan in the tibio-tarsal joint induced a dose and time-dependent hypernociception elicited by articular dorsal flexion movement. Maximal joint hypernociception was detected between 7 and 24 h after zymosan injection, and matched maximal inflammation score as determined by histopathology and neutrophil migration assay. In agreement with the inflammatory hypernociceptive paradigm, flexion-elicited hypernociception induced by zymosan was dose-dependently inhibited by morphine (2-8 mg/kg) and by an effective dose of indomethacin (5 mg/kg). The present study demonstrated that the tibio-tarsal flexion reflex is a behavioral nociceptive model that allows a quantitative evaluation of inflammatory joint hypernociception in mice and its pharmacological modulation.

Low viscosity hydrogel of guar gum: preparation and physicochemical characterization.

Guar gum was cross-linked with glutaraldehyde and characterized by GPC, rheology, WADX, SEM and TGA. This guar gum is a galactomannan polysaccharide, that contains small amount of arabinose, glucose and uronic acid, besides galactose and mannose. The polymer has high molar mass, with Mw, Mn and Mv values of 2.0x10(6), 1.2x10(6) and 1.9x10(6)g/mol, respectively. The reticulation follows a slow process and lead to a viscosity increase of 40 times compared with the original gum solution. The final viscosity was similar to that of Hylan G-F 20, a hyaluronate derivative, commercially used in viscosupplementation treatment. The gel contains 95.6% of water and the amount of residual glutaraldehyde is much lower than the LD-50. Porous structure was detected by SEM and thermal stability was improved by the cross-linking. The low viscosity, the small amount of remained glutaraldehyde, and the thermal stability indicates that the guar hydrogel has potential to be applied as biomaterial with specific rheological requirements.

Antihyperalgesic effect of pentoxifylline on experimental inflammatory pain.

The antihyperalgesic effect of pentoxifylline was investigated in three experimental pain models. Pentoxifylline (0.5-1.6 mg kg(-1)) given 30 min before the stimulus significantly inhibited the writhing response induced by the intraperitoneal (i.p.) administration of either acetic acid (-90%) or zymosan (-83%), but not that of iloprost, in mice, as well as the zymosan-induced articular hyperalgesia in the zymosan arthritis in rats (-50%). Pentoxifylline also inhibited the mechanical hypernociception in rats induced by the intraplantar injection of either carrageenin (-81%), bradykinin (-56%) or tumor necrosis factor alpha (TNF-alpha; -46%), but not that induced by interleukin-1beta (IL-1beta) or prostaglandin E(2) (PGE(2)). Pentoxifylline did not inhibit the nociceptive response in the hot plate test in mice. Further, the antinociceptive effect of pentoxifylline in the writhing test in mice and the zymosan-induced articular hyperalgesia were not reversed by the coadministration of the opioid receptor antagonist naloxone. Thus, pentoxifylline antinociceptive effect is probably not mediated at a central level. Pentoxifylline significantly reduced TNF-alpha (-43%) and IL-1beta (-42%) concentrations in the joint exudates of rats stimulated by intra-articular injection of zymosan and the production of both cytokines (-66 and -86%, respectively) by mouse peritoneal macrophages stimulated in vivo with zymosan as well as the expression of TNF-alpha at the tissue level in carrageenin-injected rat paws. In conclusion, the antinociceptive activity of pentoxifylline is associated with the inhibition of the release of both TNF-alpha and IL-1beta.

Tumour necrosis factor-alpha mediates neutrophil migration to the knee synovial cavity during immune inflammation.

Tumour necrosis factor (TNF)-alpha, interleukin-1beta, interleukin-8 and leukotriene B4 have an important role on neutrophil recruitment during immune-inflammation. Here we evaluated the participation of several inflammatory mediators on ovalbumin-induced neutrophil recruitment in the knee articular space of immunized rats. Ovalbumin administration in immunized, but not in control, rats induced a dose- and time-dependent neutrophil accumulation, which was inhibited by dexamethasone, pentoxifylline or thalidomide, but not by selective inhibitors of nitric oxide (nitro-L-arginine), platelet-activating factor (BN50730 or UK74505), prostaglandins (indomethacin), histamine (meclisine) or leukotriene B4 (MK 886 and CP105,696). Anti-TNF-alpha antiserum, but not anti-interleukin-1beta or anti-CINC-1 (cytokine-induced neutrophil chemoattractant 1) antisera, impaired ovalbumin-induced neutrophil accumulation. High amounts of TNF-alpha were detected in the exudates, which was inhibited by dexamethasone, pentoxifylline and thalidomide. These results suggest a specific role for TNF-alpha in this model, and the ability of pentoxifylline and thalidomide to inhibit both neutrophil influx and TNF-alpha release may have therapeutic implications in arthritis.

Dual effect of nitric oxide in articular inflammatory pain in zymosan-induced arthritis in rats.

The contribution of nitric oxide (NO) to articular pain in arthritis induced by zymosan (1 mg, intra articular) in rats was assessed by measuring articular incapacitation (AI). Systemic treatment with the non-selective NO synthase (NOS) inhibitor L-NAME (10 - 100 mg kg(-1) i.p.) or with the selective iNOS inhibitors aminoguanidine (AG; 10 - 100 mg kg(-1) i.p.) or 1400W (0.5 - 1 mg kg(-1) s.c.) inhibited the AI induced by injection of zymosan 30 min later. Local (intra articular) treatment with the NOS inhibitors (L-NAME or AG, 0.1 - 1 micromol; 1400W, 0.01 (micromol) 30 min before zymosan also inhibited the AI. Systemic or local treatment with the NOS inhibitors (L-NAME; AG, 100 mg kg(-1) i.p. or 0.1 micromol joint(-1); 1400W, 1 mg kg(-1) s.c. or 0.01 micromol joint(-1)), 2 h after zymosan did not affect the subsequent AI. Local treatment with the NO donors SNP or SIN-1, 2 h after zymosan did inhibit AI. L-NAME and AG, given i.p. inhibited nitrite but not prostaglandin E(2) (PGE(2)) levels in the joints. L-NAME (100 mg kg(-1)) but not AG (100 mg kg(-1)) increased mean arterial blood pressure. Neither L-NAME, AG nor the NO donor SIN-1 altered articular oedema induced by zymosan. In conclusion, inhibitors of iNOS decrease pain in zymosan arthritis only when given before the zymosan. This was not due to inhibition of articular PGE(2) release or oedema. NO donors also promoted antinociception in zymosan arthritis without affecting oedema.