Oral vitamin C reduces the injury to skeletal muscle caused by compartment syndrome

Investigation of the biochemical and histopathological effects of vitamin C, selenium, and therapeutic ultrasound on muscle damage in rats

Muscle injury is a common type of soft tissue injury. Increased oxidative damage has been reported after muscle injuries. Therapeutic ultrasound is commonly used for such injuries. This study compared the efficacy of therapeutic ultrasound treatment and various antioxidant agents in experimental muscle injuries. For this purpose, some serum enzymes, oxidative stress, and inflammatory markers were evaluated together with histopathological examinations. Six groups were formed with 6 male Wistar albino rats in each group. These groups were control, only injury (OI), ultrasound (U), vitamin C (Vit C), selenium (S), and mixture (M). Muscle injury was caused by a laceration of the gastrocnemius muscle in all groups except the control group. No treatment was performed in the OI group. At the end of the 6-day application, all rats were sacrificed. As for serum enzymes, CK, ALT, and AST levels returned to control values in almost all treatment groups. Total oxidative status (TOS) and oxidative stress index (OSI) increased in the OI group, while they decreased in the S and M groups. In addition, the decrease in MPO activity in the blood tissue of the Vit C group was statistically significant. There were no significant changes between groups in terms of serum inflammatory markers and histological findings. This study has shown that the ingestion of vitamin C and selenium may contribute to the treatment of muscle injury in addition to therapeutic ultrasound treatment. However, further studies are needed to support these results.

Acute Compartment Syndrome in the Athlete

In sports, acute compartment syndrome (ACS) develops following lower limb fracture, with subsequent high intracompartmental pressures and pain out of proportion to the physical examination. A prompt diagnosis is the key to a successful outcome in patients with ACS. The goal of treatment of ACS, namely decompressive fasciotomy, is to reduce intracompartmental pressure and facilitate reperfusion of ischemic tissue before onset of necrosis. A delay in diagnosis and treatment may result in devastating complications, including permanent sensory and motor deficits, contractures, infection, systemic organ failure, limb amputation, and death.

Bioactivity of Falkenbergia rufolanosa Methanolic Extract: Assessment of Its Effect on Methyl-Thiophanate Induced Bone and Blood Disorders

This study aimed to evaluate the potentiality of a mineral and antioxidant-rich methanolic extract of the red marine alga Falkenbergia rufolanosa (FRE) against methyl-thiophanate (MT)-induced toxicity in adult rats. The animals were allocated into four groups: controls, MT (300 mg/kg), MT + FRE, and FRE-treated group for 7 days. Our results demonstrated severe mineral perturbations due to MT treatment, especially in calcium and phosphorus levels in plasma, urine, and bone. Similarly, the hematological analysis revealed increased red blood cells, platelets, and white blood cells associated with striking genotoxicity. Interestingly, a significant rise in lipid peroxidation and advanced oxidation protein products level in erythrocytes and bone were noted. Meanwhile, a depletion of the antioxidant status in both tissues occurred. These biochemical alterations were in harmony with DNA degradation and histological variation in bone and blood. In the other trend, data showed that treatment with alga improved MT-induced hematotoxicity, genotoxicity, and oxidative stress in the blood and bone. Osteo-mineral metabolism and bone histo-architecture were also noted. In conclusion, these findings demonstrated that the red alga Falkenbergia rufolanosa is a potent source of antioxidant and antibacterial agents, as revealed by the in vitro analysis.

Complex Regional Pain Syndrome and Distal Radius Fracture: Etiology, Diagnosis, and Treatment

Complex regional pain syndrome (CRPS) is a chronic pain condition characterized by a constellation of signs and symptoms including pain out of proportion to the injury or insult, autonomic dysfunction, trophic changes, and impaired function. CRPS may occur following either conservative or surgical management of distal radius fractures and can significantly complicate the trajectory of a patient's recovery. Although the incidence, diagnosis, prevention, and treatment of this condition have been extensively studied, optimal methods to identify, prevent, and treat this condition remain controversial. This article reviews the available literature on the diagnosis and treatment of CRPS in distal radius fractures.

Lycopene hampers lung injury due to skeletal muscle ischemia-reperfusion in rat model

This study investigates lycopene's preventive efficacy in skeletal muscle ischemia-reperfusion (I/R) induced lung injury. Thirty-two rats were randomly assigned to control group, lycopene group, I/R group and I/R + lycopene group. In the lycopene and I/R + lycopene groups, the rats initially received 10 mg/kg/day lycopene orally for 15 days. Then, dissection around the abdominal aorta was performed in all rats under general anesthesia. The aorta was clamped at the infrarenal level in the I/R group and I/R + lycopene group for two hours before two hours of reperfusion. The mean serum levels of malondialdehyde (53.0 ± 20.14 nmol/mL) and superoxide dismutase (1.03 ± 0.16 U/mL) were higher and lower in the I/R group than the other three groups, respectively (p < 0.001). The mean serum IMA level of I/R + lycopene group (0.42 ± 0.04 abs/u) was lower than the I/R group (0.47 ± 0.04 abs/u) (p = 0.015). The mean tissue malondialdehyde levels of I/R group (69.10 ± 11.55 nmol/mL) and I/R + lycopene group (68.36 ± 21.17 nmol/mL) were high compared to the control group (49.87 ± 6.52 nmol/mL) and lycopene group (47.82 ± 4.44 nmol/mL) (p = 0.002). The mean tissue glutathione peroxidase (p < 0.001) and superoxide dismutase (p = 0.001) levels of I/R group (121.81 ± 43.59 nmol/mL and 25.17 ± 8.69 U/mL) were low compared to the control group (236.12 ± 18.01 nmol/mL and 46.30 ± 5.17 U/mL), lycopene group (227.52 ± 16.92 nmol/mL and 45.82 ± 4.02 U/mL), and I/R + lycopene group (176.02 ± 24.27 nmol/mL and 35.20 ± 4.85 U/mL). The histopathological analyses of I/R + lycopene group indicated less significant changes than the control group. Tissue damage in the I/R + lycopene group was less prominent than the I/R group. These findings suggest oral lycopene supplementation as a promising prevention against skeletal muscle I/R caused lung injury.

Influence of vitamin C on the incidence of CRPS-I after subacromial shoulder surgery

PURPOSE

The primary aim of this study was to determine whether postoperative administration of vitamin C (VC) is associated with reduced risk of complex regional pain syndrome type I (CRPS-I) after subacromial shoulder surgery (SaSS). The secondary objective of the study was to identify risk factor for the development of CRPS-I after SaSS.

MATERIALS AND METHODS

A retrospective cohort study was performed to evaluate 542 patients undergoing SaSS from January 2015 to December 2016. The cohort was divided into two groups based on VC administration [Group I (no VC) and Group II (500 mg/day oral VC for 50 days postoperatively)]. The relationship between VC administration and development of CRPS-I was assessed. Demographics, preoperative clinical parameters, and operative variables were evaluated to determine their effect on the incidence of CRPS-I.

RESULTS

A total of 267 patients (Group II) undergoing SaSS received VC, and 266 patients (Group I) did not. The incidence of CRPS-I was significantly different between two groups (36(13%) vs 18(7%), p = 0.009). Multivariable regression, however, demonstrated that VC reduced the risk of CRPS-I after SaSS by > 50% (aOR = 0.49; 95% CI 0.27-0.91). Patients undergoing open surgery (aOR = 2.19; 95% CI 1.2-4.0) were more likely to develop CRPS-I postoperatively. Higher preoperative Constant score (aOR = 0.94; 95% CI 0.91-0.98) was associated with lower risk for CRPS-I development.

CONCLUSIONS

The present study found that VC administered prophylactically for 50 days postoperatively is effective in preventing CRPS-I development after SaSS. CRPS-I is a common complication following SaSS, especially in the setting of an open approach. The authors recommend preventive management with VC and arthroscopic approaches when possible for SaSS.

LEVEL OF EVIDENCE III

Retrospective comparative study.

Ascorbic Acid Attenuates Multifidus Muscles Injury and Atrophy After Posterior Lumbar Spine Surgery by Suppressing Inflammation and Oxidative Stress in a Rat Model

STUDY DESIGN

A rat model of multifidus muscles injury and atrophy after posterior lumbar spine surgery.

OBJECTIVE

We determined the effect of ascorbic acid (AA) on the postoperative multifidus muscles in rat model.

SUMMARY OF BACKGROUND DATA

Previous studies show oxidative stress and inflammation are two main molecular mechanisms in multifidus muscle injury and atrophy after posterior lumbar surgery. AA may have a protective effect in postoperative multifidus muscles.

METHODS

Rats were divided into sham surgery, control surgery, and surgery plus AA groups. Multifidus muscles of the control and AA groups were excised from the osseous structures. The muscles were retracted continuously for 2 hours. In the sham and AA groups, AA was administered via oral gavage daily in the first week. In each group, the oxidative stress was evaluated by measuring malondialdehyde (MDA) and Total superoxide dismutase (T-SOD). The inflammation, fat degeneration, or fibrosis of multifidus muscle were evaluated by quantitative real-time polymerase chain reaction (q-PCR), histology, or immunohistochemical analysis.

RESULTS

T-SOD activity was significantly lower in the control group than that in the AA group in the first week. MDA levels were significantly higher in the AA group. Interleukin-6 and tumor necrosis factor-α in multifidus muscles also showed significant differences when treated with AA. The inflammation score on histology was significantly lower in the AA group postoperatively in the first week. In the long run, marker genes for fibrosis and fat degeneration, and fibrosis and fat degeneration scores, were significantly lower in the AA than the control group on days 14 and 28 postoperatively.

CONCLUSION

In conclusion, AA attenuated the oxidative stress and inflammation response in the postoperative multifidus muscles, and remarkable differences were observed from the histological assessment and related marker genes expression. Our results provided important insight into the anti-inflammatory and anti-oxidative effects of AA in the postoperative multifidus muscles.

LEVEL OF EVIDENCE

N/A.

Bradykinin Impairs and HOE 140 does not Protect Rat Hindlimb Skeletal Muscle Against Tourniquet-induced Reperfusion Injury

BACKGROUND

Bradykinin (BK) is used in different tissues. Dose-dependent studies have demonstrated that low doses protect against ischemia/reperfusion (I/R) injury while higher doses lead to adverse effects. Although the beneficial effects of BK infusion were observed in myocardium, its role on the I/R impact in skeletal muscle (SM) has not been fully clarified.

OBJECTIVE

This study was carried out to evaluate the effects of BK, administered in the hindlimbs of rats subjected to I/R.

METHODS

The study design included three experimental groups: Group 1 control (saline), Group 2 (bradykinin), and Group 3 (HOE 140, a BK2 receptor blocker). In all three groups, rats were subjected to hindlimb ischemia for a total of 2 h followed by continuous 4 h of reperfusion with pharmacological interventions. The methods include analysis of enzymes (lactate dehydrogenase-LDH and creatinine phosphokinase-CPK), cell membrane marker of injury (malondialdeyde-MDA), recruitment of neutrophils (myeloperoxidase-MPO), and apoptosis index (immunohistochemistry TUNEL in situ peroxidase dead end).

RESULTS

Except for the apoptotic index, all parameters studied were shown to be elevated in the reperfusion group intervened with BK. The blocking of BK2 receptors by HOE 140 did not affect the I/R injury.

CONCLUSION

After 2 h of total ischemia, infusion of bradykinin during 4 h of reperfusion, worsened the I/R injury in the hindlimb skeletal muscle.

Contribution of inflammation to cellular injury in compartment syndrome in an experimental rodent model

Compartment syndrome, a devastating consequence of limb trauma, is characterised by severe tissue injury and microvascular perfusion deficits. We hypothesised that leucopenia might provide significant protection against microvascular dysfunction and preserve tissue viability. Using our clinically relevant rat model of compartment syndrome, microvascular perfusion and tissue injury were directly visualised by intravital video microscopy in leucopenic animals. We found that while the tissue perfusion was similar in both groups (38.8% (standard error of the mean (sem) 7.1), 36.4% (sem 5.7), 32.0% (sem 1.7), and 30.5% (sem 5.35) continuously-perfused capillaries at 45, 90, 120 and 180 minutes compartment syndrome, respectively versus 39.2% (sem 8.6), 43.5% (sem 8.5), 36.6% (sem 1.4) and 50.8% (sem 4.8) at 45, 90, 120 and 180 minutes compartment syndrome, respectively in leucopenia), compartment syndrome-associated muscle injury was significantly decreased in leucopenic animals (7.0% (sem 2.0), 7.0%, (sem 1.0), 9.0% (sem 1.0) and 5.0% (sem 2.0) at 45, 90, 120 and 180 minutes of compartment syndrome, respectively in leucopenia group versus 18.0% (sem 4.0), 23.0% (sem 4.0), 32.0% (sem 7.0), and 20.0% (sem 5.0) at 45, 90, 120 and 180 minutes of compartment syndrome in control, p = 0.0005). This study demonstrates that the inflammatory process should be considered central to the understanding of the pathogenesis of cellular injury in compartment syndrome.

Cite this article: Bone Joint J 2015;97-B:539–43

Testing the validity of preventing chronic regional pain syndrome with vitamin C after distal radius fracture. [Corrected]

PURPOSE

The American Academy of Orthopaedic Surgeons recommends the use of vitamin C to prevent complex regional pain syndrome (CRPS) for patients with distal radius fractures (DRFs). We hypothesized that the evidence for supporting this recommendation is weak, based on epidemiological principles of association and causality. The specific aim of this project was to test the validity of this recommendation.

METHODS

We conducted a literature review to retrieve articles reporting on the use of vitamin C to prevent CRPS. Data collected included sample size, study design type, dose of vitamin C used, and outcome measures of association expressed as relative risk (RR) and odds ratio. We then applied Hill criteria to evaluate the relationship between vitamin C and CRPS.

RESULTS

We obtained 225 articles from the database search. After the exclusion of duplicates, unrelated articles, editorial letters, and commentaries, we found 4 articles and 1 systematic review relevant to our topic. Six of the 9 Hill criteria were met, and an earlier meta-analysis showed a quantified reduction in CRPS risk. However, criteria like biological plausibility, specificity, and coherence were not met.

CONCLUSIONS

The number of causal/association criteria met was adequate to support the scientific premise of the effect of vitamin C in preventing CRPS after DRF. Furthermore, vitamin C administration is of relatively low cost and has few complications unless administered in large doses. Owing to sufficient epidemiological evidence availability, the American Academy of Orthopaedic Surgeons recommendation of vitamin C to prevent CRPS has practical merit.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic II.

The influence of vitamin C on the outcome of distal radial fractures: a double-blind, randomized controlled trial

BACKGROUND

Vitamin C has been proposed to improve outcomes after a distal radial fracture by promotion of bone and soft-tissue healing and reduction of the prevalence of complex regional pain syndrome (CRPS). Our primary aim was to examine the effect of vitamin C on functional outcome after a distal radial fracture.

METHODS

A total of 336 adult patients with an acute fracture of the distal aspect of the radius were recruited over a one-year period and randomized to receive 500 mg of vitamin C or placebo daily for fifty days after the fracture. The primary outcomes were the DASH (Disabilities of the Arm, Shoulder and Hand) score at six weeks and at one year. Secondary variables included complications, wrist and finger motion, grip and pinch strength, pain, and a CRPS score.

RESULTS

There were no significant differences in patient or fracture characteristics between the treatment groups. There was no significant effect of vitamin C on the DASH score throughout the study period. At six weeks, patients in the vitamin C group with a nondisplaced fracture had a significantly greater wrist flexion deficit (p = 0.008) and pinch strength deficit (p = 0.020) and a greater rate of CRPS (p = 0.022), but there was no difference in the CRPS rate at any other time point. At twenty-six weeks, there was a higher rate of complications (p = 0.043) and greater pain with use (p = 0.045) in the patients with a displaced fracture treated with vitamin C. There was no significant difference in the time to fracture-healing.

CONCLUSIONS

This study demonstrated no significant difference at one year in the DASH score, other functional outcomes, the rate of CRPS, or osseous healing of nondisplaced or displaced distal radial fractures treated with vitamin C compared with placebo. We conclude that administration of vitamin C confers no benefit to patients with a displaced or nondisplaced fracture of the distal aspect of the radius.

LEVEL OF EVIDENCE

Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

The effects of hypothermia and L-arginine on skeletal muscle function in ischemia-reperfusion injury

OBJECTIVES

Ischemia-reperfusion (I/R) injury can have detrimental effects on skeletal muscle. We have shown that vessel permeability can be minimized in a hypothermic setting and also by administering the nitric oxide synthase (NOS) stimulator, L-arginine, at physiologic temperatures. The purpose of this study was to examine and compare skeletal muscle contractility after an I/R insult during hypothermic conditions, warm conditions, and also with the administration of L-arginine at physiologic temperatures. We hypothesized that hypothermia and L-arginine administration will also demonstrate protective effects to skeletal muscle contractility.

METHODS

Using Sprague-Dawley rats, the extensor digitorum longus muscle was rotated on its vascular pedicle to a thermo-controlled stage. Ischemia was established using an atraumatic femoral artery tourniquet. Reperfusion was performed under control and experimental conditions including local hypothermia and intravenous L-arginine. After harvesting experimental muscles, contractility was then quantified by using a tissue bath stimulator with force transducers.

RESULTS

Warm reperfusion resulted in marked decrease in muscle contractility compared with sham animals. Local hypothermia showed statistically significant preservation of contractility compared with the sham group. This protective effect was recapitulated by the application of NOS inducers (L-arginine) at warm conditions.

CONCLUSIONS

These findings demonstrate that hypothermia and L-arginine are protective of skeletal muscle contractility after an I/R injury. The results presented may have profound effects on future therapeutic recommendations and suggest possible pathways for clinical intervention to modulate I/R injury, which is commonplace in orthopaedic trauma and reconstructive surgery.

The effect of ischemia reperfusion injury on skeletal muscle

Ischemia reperfusion (IR) injury occurs when tissue is reperfused following a period of ischemia, and results from acute inflammation involving various mechanisms. IR injury can occur following a range of circumstances, ranging from a seemingly minor condition to major trauma. The intense inflammatory response has local as well as systemic effects because of the physiological, biochemical and immunological changes that occur during the ischemic and reperfusion periods. The sequellae of the cellular injury of IR may lead to the loss of organ or limb function, or even death. There are many factors which influence the outcome of these injuries, and it is important for clinicians to understand IR injury in order to minimize patient morbidity and mortality. In this paper, we review the pathophysiology, the effects of IR injury in skeletal muscle, and the associated clinical conditions; compartment syndrome, crush syndrome, and vascular injuries.

Indomethacin reduces cell damage: shedding new light on compartment syndrome

INTRODUCTION

Indomethacin may preserve tissue viability in compartment syndrome. The mechanism of improved tissue viability is unclear, but the anti-inflammatory effects may alter the relative contribution of tissue necrosis versus apoptosis to cellular injury. Existing studies have only considered indomethacin administration before induction of elevated intracompartment pressure. The purpose of this study was to determine the effect of timing of indomethacin administration on muscle damage in elevated intracompartment pressure and to assess apoptosis as a cause of tissue demise.

METHODS

Twenty-four Wistar rats were randomized to elevated intracompartmental pressure (EICP) for either 45 or 90 minutes (30 mmHg). In the 45-minute cohort, indomethacin was withheld in Group 1 (CS45), given before induction of EICP in Group 2 (CS45Indo0), or given after 30 minutes of EICP/15 minutes before fasciotomy in Group 3 (CS45Indo30). In the 90-minute cohort, indomethacin was withheld in Group 4 (CS90) or given after 30 or 60 minutes of EICP in Groups 5 (CS90Indo30) and 6 (CS90Indo60). Intravital microscopy and fluorescent staining assessed capillary perfusion, cell damage, and inflammatory activation within extensor digitorum longus muscle. Apoptosis was assessed using spectrophotometric assessment of caspase levels. Groups 1 to 3 and 4 to 6 were compared using analysis of variance with P < 0.05 deemed significant.

RESULTS

Perfusion and tissue viability improved in indomethacin-treated groups. Nonperfused capillaries decreased from Group 1 (CS45) (50.1 +/- 2.5) to Group 2 (CS45Indo0) (38.4 +/- 1.8) and Group 3 (CS45Indo30) (14.13 +/- 1.73) (P < 0.05). Similarly, Group 5 (CS90Indo30) and Group 6 (CS90Indo60) had 25% fewer nonperfused capillaries compared with Group 4 (CS90) (P < 0.0001). Group 2 (CS45Indo0) and Group 3 (CS45Indo30) showed fewer damaged cells (1% +/- 0.5% and 8.7% +/- 2%) compared with Group 1 (CS45) (20% +/- 14%) (P < 0.0001). Group 5 (CS90Indo30) showed decreased cell damage (13% +/- 1%) compared with Group 4 (CS90) (18% +/- 1%) (P < 0.01). Group 6 (CS90Indo60) also showed decreased cell damage (11% +/- 1%) compared with Group 4 (CS90) (18% +/- 1%); however, this difference was not significant (P > 0.05). Apoptotic activity was present with elevated intracompartment pressure. At 30 minutes, there were elevated caspase levels in Group 4 and Group 6 EICP groups (0.47 +/- 0.08) compared with control subjects (0.19 +/- 0.02) (P < 0.003). However, indomethacin-treated groups did not differ from control subjects with regard to caspase levels (P > 0.05).

CONCLUSION

Indomethacin decreased cell damage and improved perfusion in elevated intracompartment pressure. The benefits of indomethacin were partially time-dependent; some improvement in tissue viability occurred regardless of timing of administration. Although apoptosis was common in elevated intracompartment pressure, the protective effect of indomethacin does not appear to be related to apoptosis.

CLINICAL RELEVANCE

Adjuvant treatment with indomethacin may improve outcome in compartment syndrome.

N-acetylcysteine protects striated muscle in a model of compartment syndrome

BACKGROUND

To avoid ischemic necrosis, compartment syndrome is a surgical emergency treated with decompression once identified. A potentially lethal, oxidant-driven reperfusion injury occurs after decompression. N-acetylcysteine is an antioxidant with the potential to attenuate the reperfusion injury.

QUESTIONS/PURPOSES

We asked whether N-acetylcysteine could preserve striated muscle contractility and modify neutrophil infiltration and activation after simulated compartment syndrome release.

MATERIALS AND METHODS

Fifty-seven rats were randomized to control, simulated compartment syndrome, and simulated compartment syndrome plus N-acetylcysteine groups. We isolated the rodent cremaster muscle on its neurovascular pedicle and placed it in a pressure chamber. Chamber pressure was elevated above critical closing pressure for 3 hours to simulate compartment syndrome. Experiments were concluded at three times: 1 hour, 24 hours, and 7 days after decompression of compartment syndrome. We assessed twitch and tetanic contractile function and tissue myeloperoxidase activity. Ten additional rats were randomized to control and N-acetylcysteine administration after which neutrophil respiratory burst activity was assessed.

RESULTS

The simulated compartment syndrome decreased muscle contractility and increased muscle tissue myeloperoxidase activity compared with controls. Treatment with N-acetylcysteine preserved twitch and tetanic contractility. N-acetylcysteine did not alter neutrophil infiltration (myeloperoxidase activity) acutely but did reduce infiltration at 24 hours, even when given after decompression. N-acetylcysteine reduced neutrophil respiratory burst activity.

CONCLUSION

N-acetylcysteine administration before or after simulated compartment syndrome preserved striated muscle contractility, apparently by attenuating neutrophil activation and the resultant oxidant injury.

CLINICAL RELEVANCE

Our data suggest a potential role for N-acetylcysteine in the attenuation of muscle injury after release of compartment syndrome and possibly in the prophylaxis of compartment syndrome.

Modulation of inflammation by vitamin E and C supplementation prior to anterior cruciate ligament surgery

Muscle atrophy commonly follows anterior cruciate ligament (ACL) injury and surgery. Proinflammatory cytokines can induce and exacerbate oxidative stress, potentiating muscle atrophy. The purpose of this study was to evaluate the influence of prior antioxidant (AO) supplementation on circulating cytokines following ACL surgery. A randomized, double-blind, placebo-controlled trial was conducted in men undergoing ACL surgery, who were randomly assigned to either: (1) AO (200 IU of vitamin E (50% d-alpha-tocopheryl acetate and 50% d-alpha-tocopherol) and 500 mg ascorbic acid), or (2) matching placebos (PL). Subjects took supplements twice daily for 2 weeks prior to and up to 12 weeks after surgery. Each subject provided five blood samples: (1) baseline (Bsl, prior to supplementation and approximately 2 weeks prior to surgery), (2) presurgery (Pre), (3) 90 min, (4) 72 h, and (5) 7 days postsurgery. Following surgery, inflammation and muscle damage increased in both groups, as assessed by increased circulating IL-6, C-reactive protein, and creatine kinase. During AO supplementation, plasma alpha-T and AA increased while gamma-T concentrations decreased significantly (P< 0.05). At 90 min the AO group displayed a significant decrease in AA, an inverse correlation between AA and (interleukin) IL-8 (r(2)= 0.50, P< 0.05), and a significantly lower IL-10 response than that of the PL group. IL-10 was significantly elevated at 90 min and 72 h in the PL group. In summary, our findings show that circulating inflammatory cytokines increase and AO supplementation attenuated the increase in IL-10 in patients post-ACL surgery.

The inflammatory response to skeletal muscle injury: illuminating complexities

Injury of skeletal muscle, and especially mechanically induced damage such as contusion injury, frequently occurs in contact sports, as well as in accidental contact sports, such as hockey and squash. The large variations with regard to injury severity and affected muscle group, as well as non-specificity of reported symptoms, complicate research aimed at finding suitable treatments. Therefore, in order to increase the chances of finding a successful treatment, it is important to understand the underlying mechanisms inherent to this type of skeletal muscle injury and the cellular processes involved in muscle healing following a contusion injury. Arguably the most important of these processes is inflammation since it is a consistent and lasting response. The inflammatory response is dependent on two factors, namely the extent of actual physical damage and the degree of muscle vascularization at the time of injury. However, long-term anti-inflammatory treatment is not necessarily effective in promoting healing, as indicated by various studies on NSAID treatment. Because of the factors named earlier, human studies on the inflammatory response to contusion injury are limited, but several experimental animal models have been designed to study muscle damage and regeneration. The early recovery phase is characterized by the overlapping processes of inflammation and occurrence of secondary damage. Although neutrophil infiltration has been named as a contributor to the latter, no clear evidence exists to support this claim. Macrophages, although forming part of the inflammatory response, have been shown to have a role in recovery, rather than in exacerbating secondary damage. Several probable roles for this cell type in the second phase of recovery, involving resolution processes, have been identified and include the following: (i) phagocytosis to remove cellular debris; (ii) switching from a pro- to anti-inflammatory phenotype in regenerating muscle; (iii) preventing muscle cells from undergoing apoptosis; (iv) releasing factors to promote muscle precursor cell activation and growth; and (v) secretion of cytokines and growth factors to facilitate vascular and muscle fibre repair. These many different roles suggest that a single treatment with one specific target cell population (e.g. neutrophils, macrophages or satellite cells) may not be equally effective in all phases of the post-injury response. To find the optimal targeted, but time-course-dependent, treatments requires substantial further investigations. However, the techniques currently used to induce mechanical injury vary considerably in terms of invasiveness, tools used to induce injury, muscle group selected for injury and contractile status of the muscle, all of which have an influence on the immune and/or cytokine responses. This makes interpretation of the complex responses more difficult. After our review of the literature, we propose that a standardized non-invasive contusion injury is the ideal model for investigations into the immune responses to mechanical skeletal muscle injury. Despite its suitability as a model, the currently available literature with respect to the inflammatory response to injury using contusion models is largely inadequate. Therefore, it may be premature to investigate highly targeted therapies, which may ultimately prove more effective in decreasing athlete recovery time than current therapies that are either not phase-specific, or not administered in a phase-specific fashion.

Delaying treatment of supracondylar fractures in children

The aim of this retrospective multicentre study was to report the continued occurrence of compartment syndrome secondary to paediatric supracondylar humeral fractures in the period 1995 to 2005. The inclusion criteria were children with a closed, low-energy supracondylar fracture with no associated fractures or vascular compromise, who subsequently developed compartment syndrome. There were 11 patients (seven girls and four boys) identified from eight hospitals in three countries. Ten patients with severe elbow swelling documented at presentation had a mean delay before surgery of 22 hours (6 to 64). One patient without severe swelling documented at presentation suffered arterial entrapment following reduction, with a subsequent compartment syndrome requiring fasciotomy 25 hours after the index procedure.

This series is noteworthy, as all patients had low-energy injuries and presented with an intact radial pulse. Significant swelling at presentation and delay in fracture reduction may be important warning signs for the development of a compartment syndrome in children with supracondylar fractures of the humerus.

Tibial compartment syndrome and the cavovarus foot

Compartment syndrome of the leg is an orthopedic emergency that requires a high index of suspicion for diagnosis and a low threshold for surgical management to prevent devastating complications. Where the clinical findings are subtle, continuous monitoring of compartment pressures, with clinical correlation, is the key to diagnosis. Surgical management should include decompression of all four compartments and early rehabilitation to prevent ischemic contracture. If contracture develops, it may cause varying degrees of equinocavovarus deformity of the foot and ankle. Appropriate evaluation and careful surgical planning that considers all components of this complex deformity are essential for obtaining good clinical results.

Antioxidants attenuate oxidative damage in rat skeletal muscle during mild ischaemia

We have previously shown oxidative stress and oedema, caused by both xanthine oxidase-derived oxidants and infiltrating neutrophils, within skeletal muscle after contractile-induced claudication. The purpose of this study was to determine whether supplementation with antioxidant vitamins attenuates the oxidative stress, neutrophil infiltration and oedema associated with an acute bout of contractile-induced claudication. Rats received vehicle, vitamin C, vitamin E or vitamin C + E for 5 days prior to contractile-induced claudication. Force production was significantly reduced in the claudicant limbs of all groups compared with the control (sham) limb of control animals. Contractile-induced claudication caused a significant increase in protein oxidation, lipid peroxidation, neutrophil infiltration and oedema compared with sham muscles. Supplementation with vitamin C, E or C + E prevented the increases in each of these, and there were no differences between groups. These findings suggest that, in an animal model of exercise-induced claudication, neutrophil chemotaxis is caused by oxidizing species and that antioxidant supplementation can prevent oxidative damage, neutrophil infiltration and oedema following an acute bout of contractile-induced claudication.

Crocus sativus L. (Saffron) extract and its active constituents (crocin and safranal) on ischemia-reperfusion in rat skeletal muscle

Saffron and its constituents have been shown to decrease ischemia-reperfusion (I/R) injury in kidney or brain tissues. In this study, the effects of saffron ethanolic extract and its constituents, crocin and safranal, were evaluated in skeletal muscle during I/R injury. Hind limb ischemia was induced using clamping the common femoral artery and vein. After 2 h ischemia, the clamp of the femoral vessels of animals was taken off and the animal underwent 1h reperfusion. Muscle injuries were evaluated by recording of the electromyographic (EMG) potentials and performing some biochemical analysis including thiobarbituric acid reactive substances (TBARS), total sulfhydryl (SH) groups and antioxidant capacity of muscle (using FRAP assay). The ethanolic extract of saffron (5, 20 and 80 mg kg(-1)), crocin (50, 200 and 400 mg kg(-1)), safranal (0.1, 0.25 and 0.5 ml kg(-1)) and normal saline (10 ml kg(-1)) were administered intraperitoneally 1 h prior reperfusion. The average peak-to-peak amplitude during I/R was significantly increased in extract, crocin and safranal groups in comparison with control-ischemic group. Following saffron, crocin and safranal administration, the total SH contents and antioxidant capacity were elevated in muscle flap. The MDA level was declined significantly in test groups. It is concluded that saffron extract and its constituents show a protective effect against lower limb I/R in rat.

Lower limb acute compartment syndrome after colorectal surgery in prolonged lithotomy position

PURPOSE

Acute compartment syndrome in patients undergoing prolonged colorectal procedures is uncommon but can have catastrophic consequences for the patient with the development of metabolic acidosis, myoglobinuric renal failure, Volkmann's contracture, limb loss, and death. The potential to produce long-term disability in a patient has important medicolegal implications, particularly if the complication is avoidable. Why only some patients develop acute compartment syndrome is not fully understood. The purpose of this study was to highlight current knowledge and suggested prevention strategies.

METHODS

A review of the relevant English language articles was performed on the basis of a MEDLINE search of the keywords: acute compartment syndrome, lithotomy position, reperfusion injury, and fasciotomy.

RESULTS

Different factors play a role: lithotomy position with or without head down, ankle and knee position, external compression for deep vein thrombosis prophylaxis, method of leg support, duration of surgery, and physiologic factors, such as gender, age, and body mass index. All efforts should be directed to prevent the establishment of acute compartment syndrome and there are accepted suggestions, such as limiting the time of leg elevation, positioning the leg below the atrium level, and monitoring postoperatively patients at risk. There is still debate on the intraoperative use of pulse oximetry to detect hypoperfusion and the appropriate use of sequential compression devices and antithromboembolic stockings.

CONCLUSIONS

Acute compartment syndrome is uncommon but cases have been reported after prolonged pelvic procedures in the lithotomy position and it is a preventable condition. More research is required to set clear guidelines on patient positioning during surgery.

The ILAILL study: iloprost as adjuvant to surgery for acute ischemia of lower limbs: a randomized, placebo-controlled, double-blind study by the italian society for vascular and endovascular surgery

SUMMARY BACKGROUND DATA

High rate of complications has been reported following revascularization for acute limb ischemia (ALI). No adjuvant pharmacologic treatment, apart from anticoagulation and standard perioperative care, has been shown clinically effective.

OBJECTIVE

Aim of this study was to evaluate the effects of the prostacyclin analog iloprost as adjuvant to surgery for ALI.

METHODS

A total of 300 patients were randomly assigned to receive perioperative iloprost (intra-arterial, intraoperative bolus of 3000 ng, plus intravenous infusion of 0.5-2.0 ng/kg/min for 6 hours/day for 4-7 days following surgery), or placebo. The primary endpoint was the combined incidence of death and amputation at 3-month follow-up. Secondary endpoints were the incidence of each single major complication, total event rate, symptomatology, and tolerability.

RESULTS

The combined incidence of death and amputation was 19.9% in the placebo and 14.1% in the iloprost group (relative risk, 1.56; 95% confidence interval, 0.89-2.75, P = 0.12, Cox regression analysis). A statistically significant lower mortality (4.7%) was reported in patients receiving iloprost, compared with controls (10.6%; relative risk, 2.61; 95% confidence interval, 1.07-6.37, P = 0.03). The overall incidence of fatal plus major cardiovascular events was 33.1% and 22.8% in placebo and iloprost groups, respectively (relative risk, 1.61; 95% confidence interval, 1.04-2.49, P = 0.03). No serious adverse reactions occurred after iloprost administration, nor differences in the incidence of bleeding or hypotension between treatment groups.

CONCLUSIONS

Although at lower levels than previously reported, our results confirm the severity of ALI. Iloprost as adjuvant to surgery significantly reduced mortality and overall major event rate. Further data are needed to support this finding, and to face a still open medical issue.

Does nutrition have a role in peripheral vascular disease?

Peripheral vascular disease (PVD) is a manifestation of systemic atherosclerosis in the lower limbs, and PVD patients have a 3- to 5-fold increased risk of cardiovascular mortality compared with age-matched controls. Nevertheless, recent reports show how PVD patients are undertreated with regard to CVD risk-factor reduction and the use of lipid-lowering or antiplatelet drugs. There is appreciable evidence that demonstrates the beneficial effects of certain nutrients and dietary habits in the prevention of CVD, but there has been little attention paid to the role of nutrients in PVD. The purpose of the present review is to provide an overview of our understanding of how foods could possibly benefit PVD. In the last few decades, several nutrients have arisen as potentially health-promoting in PVD. While nutritional interventions in PVD show positive clinical effects for fish oil, carnitine or vitamin E, others such as olive oil or vitamin C seem to interact only at a biochemical level by decreasing risk factors. Moreover, only epidemiological associations exist for the potential role of fibre, folates or vitamin B6 in this disease. In all cases, the limited data available provide no clear-cut evidence in favour of the clinical benefit of nutritional interventions aimed at reducing risk factors and ameliorating symptoms in PVD patients. No practical recommendations can be given at this stage, and further studies are clearly needed.