Following ischaemia-reperfusion (I-R) tissues undergo a neutrophil mediated oxidant injury. Vitamin C is a water-soluble endogenous anti-oxidant, which has been shown in previous studies to abrogate neutrophil mediated endothelial injury. Our aim was to evaluate Vitamin C supplementation in the prevention of I-R induced acute muscle injury. Sprague-Dawley rats (n-6/group) were randomised into control, I-R and I-R pretreated with Vitamin C (3.3g over 5 days). Cremasteric muscle was isolated on its neuro-vascular pedicle and I-R injury induced by clamping the pedicle for 3 hours, the tissue was subsequently reperfused for 60 minutes. Following reperfusion muscle function was assessed by electrical field stimulation: peak twitch (PTV), maximum tetanus (MTV) and fatigability values were recorded. Tissue neutrophil infiltration was assessed by tissue myeloperoxidase (MPO) activity and tissue oedema by wet:dry ratio (WDR). Ischaemia-reperfusion (I-R) resulted in a significant decrease in muscle function (PTV< MTV) there was no difference in fatigability values between groups. I-R also resulted in a significant increase in neutrophil infiltration (MPO) and tissue oedema (WDR). Pre-treatment with Vitamin C attenuated I-R injury as assessed by these parameters. This data suggests that oral Vitamin C reduce I-R induced acute muscle injury, possibly by attenuating neutrophil mediated tissue injury

Matsen in 1975 described Compartment Syndrome (CS) as a condition in which the circulation and function of tissues within a closed space are compromised by increased pressure within that space. Raised intra-compartmental pressures result in progressive venous obstruction, capillary stagnation and microvascular hypoxia. N-acetyl cysteine (NAC) is an anti-oxidant used clinically to reduce liver injury following paracetamol overdose. NAC has been shown previously to reduce lung injury following exposure to endotoxin. Our aim was to evaluate the efficacy of n-acetyl cysteine in the prevention of CS induced acute muscle injury. Sprague-Dawley rats (n=6/group) were randomised into Control, CS and CS pre-treated with N-Acetyl Cysteine (0.5g/kg i.p. 1 hr prior to induction). Cremasteric muscle was isolated on its neuro-vascular pedicle and CS injury was induced by placing the muscle in a specially designed pressure chamber. Arterial blood pressure was measured via a cannula placed in the carotid artery. To induce compartment syndrome chamber pressure was maintained at diastolic-10 mm Hg. After three hours pressure was released stimulating surgical fasciotomy. One hour after decompression muscle function was assessed by electrical field stimulation: peak twitch (PTV) and maximum tetanus (MTV) values were recorded. Tissue oedema was assessed by wet to dry ratio (WDR). Compartment Syndrome (CS) resulted in a significant decrease in muscle function (PTV, MTV). CS also resulted in a significant increase in tissue oedema (WDR). Pre-Treatment with N-Acetyl Cysteine attenuated CS injury as assessed by these parameters. These data show that administration of the anti-oxidant N-Acetyl Cysteine results in significant attenuation of the muscle injury and oedema caused by Compartment Syndrome. This work was supported by a grant from the Cappagh Trust

Aims. The primary objective of this study was to develop a validated classification system for assessing iatrogenic bone trauma and soft-tissue injury during total hip arthroplasty (THA). The secondary objective was to compare macroscopic bone trauma and soft-tissues injury in conventional THA (CO THA) versus robotic arm-assisted THA (RO THA) using this classification system. Methods. This study included 30 CO THAs versus 30 RO THAs performed by a single surgeon. Intraoperative photographs of the osseous acetabulum and periacetabular soft-tissues were obtained prior to implantation of the acetabular component, which were used to develop the proposed classification system. Interobserver and intraobserver variabilities of the proposed classification system were assessed. Results. The BOne trauma and Soft-Tissue Injury classification system in total Hip arthroplasty (BOSTI Hip) grades osseous acetabular trauma and periarticular muscle damage during THA. The classification system has an interclass correlation coefficient of 0.90 (95% CI 0.86 to 0.93) for interobserver agreement and 0.89 (95% CI 0.84 to 0.93) for intraobserver agreement. RO THA was associated with improved BOSTI Hip scores (p = 0.002) and more pristine osseous surfaces in the anterior superior (p = 0.001) and posterior superior (p < 0.001) acetabular quadrants compared with CO THA. There were no differences between the groups in relation to injury to the gluteus medius (p = 0.084), obturator internus (p = 0.241), piriformis (p = 0.081), superior gamellus (p = 0.116), inferior gamellus (p = 0.132), quadratus femoris (p = 0.208), and vastus lateralis (p = 0.135), but overall combined muscle injury was reduced in RO THA compared with CO THA (p = 0.023). Discussion. The proposed BOSTI Hip classification provides a reproducible grading system for stratifying iatrogenic bone trauma and soft-tissue injury during THA. RO THA was associated with improved BOSTI Hip scores, more pristine osseous acetabular surfaces, and reduced combined periarticular muscle injury compared with CO THA. Further research is required to understand if these intraoperative findings translate to differences in clinical outcomes between the treatment groups. Cite this article: Bone Joint J 2024;106-B(9):898–906

Aims. The aim of the HIPGEN consortium is to develop the first cell therapy product for hip fracture patients using PLacental-eXpanded (PLX-PAD) stromal cells. Methods. HIPGEN is a multicentre, multinational, randomized, double-blind, placebo-controlled trial. A total of 240 patients aged 60 to 90 years with low-energy femoral neck fractures (FNF) will be allocated to two arms and receive an intramuscular injection of either 150 × 10. 6. PLX-PAD cells or placebo into the medial gluteal muscle after direct lateral implantation of total or hemi hip arthroplasty. Patients will be followed for two years. The primary endpoint is the Short Physical Performance Battery (SPPB) at week 26. Secondary and exploratory endpoints include morphological parameters (lean body mass), functional parameters (abduction and handgrip strength, symmetry in gait, weightbearing), all-cause mortality rate and patient-reported outcome measures (Lower Limb Measure, EuroQol five-dimension questionnaire). Immunological biomarker and in vitro studies will be performed to analyze the PLX-PAD mechanism of action. A sample size of 240 subjects was calculated providing 88% power for the detection of a 1 SPPB point treatment effect for a two-sided test with an α level of 5%. Conclusion. The HIPGEN study assesses the efficacy, safety, and tolerability of intramuscular PLX-PAD administration for the treatment of muscle injury following arthroplasty for hip fracture. It is the first phase III study to investigate the effect of an allogeneic cell therapy on improved mobilization after hip fracture, an aspect which is in sore need of addressing for the improvement in standard of care treatment for patients with FNF. Cite this article: Bone Jt Open 2022;3(4):340–347

Purpose of the study: The purpose of this study was to assess traumatic damage to muscles using biological markers. Two approaches were evaluated: a modified Hardinge approach (anterior hemimyotomy) and a reduced anterolateral approach (Rottinger). Material and method: This was a multicentric prospective study conducted in three centres in 2008. The first 50 patients in each centre were included. Total creatinine phosphokinase (CPK) and serum myoglobulin levels were used to evaluate muscle damage. Blood samples were taken ten hours after surgery for myoglobulaeia and at one and two postoperative days for CPK. Student’s t test was used for the statistical analysis. Results: There was no statistically significant difference in serum myoglobulin levels 10 hours postoperatively (p=0.25) or for CPK level at day 1 (p=0.098) and day 2 (p=0.105). Objective clinical recovery (Postel-Merle-d’Aubigné, Harris) and function (WOMAC and SF-12) were better at six weeks with the reduced anterolateral approach. Discussion: These findings show that muscle aggression after mini-incision is to the same order as with the standard approach. The damage is however different: section for the Hardinge type approaches, stretching and contusion for the mini-incisions. Conclusion: Use of biological markers specific for muscle tissue appears to be a simple way of quantifying muscle damage. However, adjunction of an imaging technique (MRI) might provide a more precise assessment of muscle injury

Elevated intracompartmental pressure (ICP) results in tissue damage due to impaired microcirculatory function. The nature of microcirculatory impairment in elevated ICP is not well understood. This study was designed to measure the effects of increased ICP on skeletal muscle microcirculation, inflammation and cell viability using intravital videomicroscopy. Twenty adult male Wistar rats were randomised to four groups: the control group (control) had no intervention; while three experimental groups had elevated ICP maintained for fifteen (15m), 45 (45m), or ninety (90m) minutes. Compartment pressure was continuously monitored and controlled between 30¡V40mmHg in the posterior hindlimb using saline infusion into the anterior hindlimb. Mean arterial pressure was maintained between 80 and 120mmHg. Fasciotomy was then performed and the Extensor Digitorum Longus muscle studied using intravital videomicroscopy. Perfusion was measured by comparing the numbers of continuous, intermittent, and nonperfused capillaries. Inflammation was measured by counting the number of activated (rolling and adherent) leukocytes in post-capillary venules. Muscle cellular Injury was measured using fluorescent vital staining of injured cell nuclei. Perfusion: The number of continuously perfused capillaries decreased from 77 ± 3/mm (control) to 46 ± 10/mm (15m),40±10/mm(45m)and27±8/mm(90m)(p< 0.05). Non-perfused capillaries increased from 13 ± 1 (control) to 16 ± 4 (15m), 30 ± 7 (45m), and 39 ± 5 (90m) (p< 0.05). Inflammation: Activated leukocytes increased from 3.6 ± 0.7/(100ƒÝ)2 (control) to 5.9 ± 1.3 (15m), 8.6 ± 1.8 (45m), and 10.9 ± 3.0/(100ƒÝ)2 (90m) (p< 0.01). Injury: The proportion of injured cells increased from 5 ± 2 % in the control group to 12 ± 3 (15m), 16 ± 7 (45m) and 20 ± 3 % (90m) (p< 0.05). As little as fifteen minutes of 30mmHg ICP caused irreversible muscle damage and microvascular dysfunction. With increased duration, further decreases in capillary perfusion and increases in injury are noted. A severe inflammatory response accompanies elevated ICP. The role of inflammation in compartment syndrome is unknown, but may contribute to cell injury and reduced capillary perfusion

Purpose: Compartment syndrome is a limb-threatening complication of skeletal trauma. Both ischemia and inflammation may be responsible for tissue necrosis in compartment syndrome (CS). In this study, normal rodents were compared with neutropenic animals to determine the importance of inflammation as a mechanism of cellular damage using techniques of intravital videomicroscopy (IVVM) and histochemical staining.

Method: Forty Wistar rats were randomised. Twenty animals served as a control (group C). Twenty rats were rendered neutropenic using cyclophosphamide (250mg/kg) (group N). Animals were anaesthetised with 5 % isoflurane. Elevated intracompartmental pressure was induced by saline infusion into the anterior hindlimb compartment and maintained at 30–40 mmHg for 0, 15, 45 or 90 minute time intervals. Following fasciotomy, the EDL muscle was analyzed using IVVM to quantify tissue injury, capillary perfusion, and inflammatory response.

Results: The proportion of injured cells decreased in group N compared to group C at all time intervals of EICP (p< 0.05). The proportion of injured cells in group N was 8 % after 0 minutes EICP, and 12, 15, and 10 % at 15, 45, and 90 min of EICP. In group C injured cells increased from 8 % to 20, 22, and 21 % at 15, 45, and 90 minutes EICP respectively. Groups N and C both demonstrated a time-dependent reduction in capillary perfusion. In group N continuously-perfused capillaries decreased from 79±4/mm with 0 min of EICP, to 48±11/mm (15min), 36±7/mm (45min), and 24±10/mm (90min) (p < 0.05). Overall, There was no difference between groups N and C with regards to perfusion (p> 0.05).

Conclusion: This study demonstrates the importance of inflammation as a cause of injury in compartment syndrome. There was a 50% decrease in injury in neutropenic animals compared to controls after 90 minutes of elevated intracompartmental pressure. Microvascular perfusion analysis demonstrated a time-dependent decrease in capillary perfusion in both neutropenic and control animals. Blocking of the inflammatory response via neutropenia was protective against tissue injury. These results provide evidence toward a potential therapeutic benefit for anti-inflammatory treatment of elevated intra-compartmental pressure.

1. The electric potentials in undeformed rabbit tibiae were measured in vivo and in vitro.

2. Surgically traumatised soft-tissues, particularly muscle, constituted the major source of voltage in vivo (up to 22 millivolts).

3. Electrical insulation of the tibia from attached soft parts abolished the high potentials on the bone.

4. Similarly high voltages could be reproduced in an excised tibia by substituting a battery for the injured muscle.

5. Changes in voltage also could be induced by altering blood flow rates or by rapid infusion of saline into the medullary space.

6. Death of the cellular elements in bone did not alter the voltage significantly.

7. The electrical contributions of the nervous system, and of dipole components of the extracellular matrix (such as collagen), either were inconsequential or of such low magnitude as to be "masked" by the larger "injury" voltages. Supported by grants from the United States Public Health Service (AM-07822) and the National Institute of Arthritis and Metabolic Diseases (TIAM-05408).

Injuries to the quadriceps muscle group are common in athletes performing high-speed running and kicking sports. The complex anatomy of the rectus femoris puts it at greatest risk of injury. There is variability in prognosis in the literature, with reinjury rates as high as 67% in the severe graded proximal tear. Studies have highlighted that athletes can reinjure after nonoperative management, and some benefit may be derived from surgical repair to restore function and return to sport (RTS). This injury is potentially career-threatening in the elite-level athlete, and we aim to highlight the key recent literature on interventions to restore strength and function to allow early RTS while reducing the risk of injury recurrence. This article reviews the optimal diagnostic strategies and classification of quadriceps injuries. We highlight the unique anatomy of each injury on MRI and the outcomes of both nonoperative and operative treatment, providing an evidence-based management framework for athletes.

Cite this article: Bone Joint J 2023;105-B(12):1244–1251.

Aims. Dystrophic calcification (DC) is the abnormal appearance of calcified deposits in degenerating tissue, often associated with injury. Extensive DC can lead to heterotopic ossification (HO), a pathological condition of ectopic bone formation. The highest rate of HO was found in combat-related blast injuries, a polytrauma condition with severe muscle injury. It has been noted that the incidence of HO significantly increased in the residual limbs of combat-injured patients if the final amputation was performed within the zone of injury compared to that which was proximal to the zone of injury. While aggressive limb salvage strategies may maximize the function of the residual limb, they may increase the possibility of retaining non-viable muscle tissue inside the body. In this study, we hypothesized that residual dead muscle tissue at the zone of injury could promote HO formation. Methods. We tested the hypothesis by investigating the cellular and molecular consequences of implanting devitalized muscle tissue into mouse muscle pouch in the presence of muscle injury induced by cardiotoxin. Results. Our findings showed that the presence of devitalized muscle tissue could cause a systemic decrease in circulating transforming growth factor-beta 1 (TGF-β1), which promoted DC formation following muscle injury. We further demonstrated that suppression of TGF-β signalling promoted DC in vivo, and potentiated osteogenic differentiation of muscle-derived stromal cells in vitro. Conclusion. Taken together, these findings suggest that TGF-β1 may play a protective role in dead muscle tissue-induced DC, which is relevant to understanding the pathogenesis of post-traumatic HO. Cite this article: Bone Joint Res 2020;9(11):742–750

The HIPGEN study funded under EU Horizon 2020 (Grant 7792939) has the aim to investigate the potential of the first regenerative cell therapy for the improvement of recovery after muscle injury in hip fracture patients. For this aim we intramuscularly injected placental derived mesenchymal stromal cells during hip fracture arthroplasty. Despite not having reached the primary endpoint, which was the Short Physical Performance Battery, we could observe an increase in abductor muscle strength and a faster return to balance looking at symmetry in insole measurements during follow up

Traditional mechanical debridement can only remove visibly infected tissue and is unable to completely clear all the biofilm that hides within muscle crevices and nerves. This study aims to determine the results of single-stage revision using noncontact low frequency ultrasonic debridement in treating chronic periprosthetic joint infections (PJI). A prospective study of consecutive patients requiring single-stage revision for chronic PJI was performed since August 2021. After mechanical debridement, an 8‑mm handheld non‑contact low‑frequency ultrasound probe was used for ultrasonic debridement at a frequency of (25±5) kHz and power of 90% for 5 minutes. Each ultrasound lasted 10 seconds with 3‑seconds intervals. The probe was repeatedly sonicated among all soft tissue and bsingle interface. The distal femoral canal and the posterior capsule of the knee were fully sonicated with a special right‑angle probe. Chemical debridement was then performed to irrigation the whole operative area. Recurrence of infection, culture results and number of colonies 24 hours after ultrasonic debridement were recorded. A total of 45 patients (25 hips and 20 knees) were included and 43 of them (95.6%) were free of infection at a mean follow-up time of 29 months (24 to 33). There were no intraoperative complications related to ultrasonic debridement (neurovascular and muscle injury, poor wound healing and fat liquefaction). The culture‑positive rate of wound liquid before ultrasonic debridement was 40.0% (18/45), which significantly increased to 75.6% (34/45) after ultrasonic debridement (P=0.001). The median number of colonies 24 hours after ultrasonic debridement was 2372 CFU/ml (310 to 4340 CFU/ml), which was significantly higher than that before debridement (307 CFU/ml; 10 to 980 CFU/ml) (P=0.000). Single-stage revision with non‑contact low‑frequency ultrasonic debridement can fully expose bacteria within biofilm, increase the efficacy of chemical debridement and lead to a favorable short‑term outcome without related complications

Purpose: Several variables related to tourniquet (TQ) inflation contribute to ischemic muscle injury. Among these the duration of ischemia has been identified as a primary factor. The purposes of this study were to investigate the following during and after TQ-induced ischemia during orthopedic trauma surgery:. muscle oxygenation changes measured by near infrared spectroscopy (NIRS);. muscle protein oxidation; and. correlations between muscle oxygenation / hemodynamics and oxidative changes. Method: Consented patients aged 19–69 yrs (n=18) with unilateral ankle fracture requiring surgery at our institution were recruited. A pair of NIRS probes was fixed over the midpoint of the tibialis anterior muscle (TA) on both the injured and healthy legs. A thigh TQ was applied to the injured leg and inflated to 300 mmHg. Using the NIRS apparatus coupled to a laptop with data acquisition software, changes in oxygenated (O2Hb), deoxygenated (HHb), and total hemoglobin (tHb) levels in the TA of both legs were measured before and during TQ inflation, and after release until values returned to baseline. PRE surgical biopsies were collected from the peroneus tertius muscle (PT) immediately after TQ inflation and incision. POST biopsies were collected from the same PT immediately before TQ deflation. Oxidation of PT myosin, actin, and total protein was quantified using Western blot analysis of 4-hydroxynonenal (4-HNE) modified proteins. Data are reported as mean±SD. Results: In PRE biopsies compared to POST biopsies there were large and statistically significant increases in the PT content of 4-NE modified myosin (174.4±128%; P< 1×10-6), actin (223.7±182%; P< 5×10-9), and total protein (567.5±378%; P< 5×10-7). There was a greater increase in PT protein oxidation in male subjects than in female subjects (50.8% difference; P< 0.05). In the TA of the fractured side, there were moderate to strong linear correlations between total protein oxidation and: the relative change in tHb (r=−0.704) and O2Hb (r=−0.415) during the period of TQ inflation and the rate at which the muscle became reoxygenated following TQ release (r=0.502). There was no relationship between muscle protein oxidation and TQ time, nor between muscle protein oxidation and age of patients. Conclusion: TQ-induced muscle ischemia for 21 to 74 min during lower extremity surgery leads to oxidative muscle injury as measured according to myofibrillar contractile protein oxidation. Importantly, we observed that when the TQ was “leaky,” local increases in muscle tHb were associated with a lower magnitude of protein oxidation, however, when local decreases in muscle O2Hb were observed, perhaps due to local blood loss below the TQ, more oxidative changes resulted. Intriguingly, gender appeared to influence the extent of muscle oxidative injury, but age did not. Surprisingly, there was no significant correlation between muscle oxidative injury and the TQ-induced ischemia interval. FUNDING: MSFHR, COF, BCLA

Summary Statement. This experimental study showed that platelet rich fibrin matrix can improve muscle regeneration and long-term vascularization without local adverse effects. Introduction. Even though muscle injuries are very common, few scientific data on their effective treatment exist. Growth Factors (GFs) may have a role in accelerating muscle repair processes and a currently available strategy for their delivery into the lesion site is the use of autologous platelet-rich plasma (PRP). The present study is focused on the use of Platelet Rich Fibrin Matrix (PRFM), as a source of GFs. Materials and Methods. Bilateral muscular lesions were created on the longissimus dorsi muscle of Wistar rats. One side of the lesion was filled with a PRFM while the contralateral was left untreated (controls). Animals were sacrificed at 5, 10, 40 and 60 days from surgery. Histological, immunohistochemical and histomorphometric analyses were performed to evaluate muscle regeneration, neovascularization, fibrosis and inflammation. The presence of metaplasic zones, calcifications and heterotopic ossification were also assessed. Results. PRFM treated muscles exhibited an improved muscular regeneration, an increase in neovascularization, and a slight reduction of fibrosis compared with controls. No differences were detected for inflammation. Metaplasia, ossification and heterotopic calcification were not detected. Conclusions. This preliminary morphological experimental study shows that PRFM use can improve muscle regeneration and long-term vascularization. Since autologous blood products are safe, PRFM may be a useful and handily product in clinical treatment of muscle injuries

A randomised controlled pre-clinical trial utilising an existing extremity war wound model compared the efficacy of saline soaked gauze to commercial dressings. The Flexor Carpi Ulnaris of anaesthetised New Zealand rabbits was exposed to high-energy trauma using computer-controlled jig and inoculated with 10. 6. Staphylococcus aureus 3 hours prior to application of dressing. After 7 days the animals were culled. Quantitative microbiological assessment of post-mortem specimens demonstrated statistically significantly reduced S aureus counts in groups treated with iodine or silver based dressings (2-way ANOVA p< 0.05). Clinical observations and haematology were performed during the study. Histopathological assessment of post-mortem muscle specimens included image analysis of digitally scanned haematoxylin and eosin stained tissue sections and subjective semi-quantitative assessment of pathology severity using light microscopy to grade muscle injury and lymph node activation. Tissue samples were also examined using scanning electron microscopy to determine the presence of bacteria and biofilm formation within the injured muscle. Non-parametric data were compared using Kruskal-Wallis. There were no bacteraemias, significantly raised white cell counts, abscesses, purulent discharge or evidence of contralateral axillary lymph node activation. All injured muscle specimens showed evidence of haemorrhage, inflammatory cell infiltration and fibrosis. All ipsilateral axillary lymph nodes were activated. There were no significant differences in the amount of muscle loss, size of the activated lymph nodes or in subjective semi-quantitative scoring criteria for muscle injury or lymph node activation. There was no evidence of bacterial penetration or biofilm formation. This study demonstrated statistically significant reductions in Staphylococcus aureus counts associated with iodine and silver dressings, and no evidence that these dressings cause harm. This was a time-limited study which was primarily powered to detect reduction in bacterial counts; however, there was no significant variation in secondary outcome measures of local or systemic infection over 7 days

Aims

Glucose-insulin-potassium (GIK) is protective following cardiac myocyte ischaemia-reperfusion (IR) injury, however the role of GIK in protecting skeletal muscle from IR injury has not been evaluated. Given the similar mechanisms by which cardiac and skeletal muscle sustain an IR injury, we hypothesized that GIK would similarly protect skeletal muscle viability.

The nervous system is known to be involved in inflammation and repair. We aimed to determine the effect of physical activity on the healing of a muscle injury and to examine the pattern of innervation. Using a drop-ball technique, a contusion was produced in the gastrocnemius in 20 rats. In ten the limb was immobilised in a plaster cast and the remaining ten had mobilisation on a running wheel. The muscle and the corresponding dorsal-root ganglia were studied by histological and immunohistochemical methods. In the mobilisation group, there was a significant reduction in lymphocytes (p = 0.016), macrophages (p = 0.008) and myotubules (p = 0.008) between three and 21 days. The formation of myotubules and the density of nerve fibres was significantly higher (both p = 0.016) compared with those in the immobilisation group at three days, while the density of CGRP-positive fibres was significantly lower (p = 0.016) after 21 days. Mobilisation after contusional injury to the muscle resulted in early and increased formation of myotubules, early nerve regeneration and progressive reduction in inflammation, suggesting that it promoted a better healing response

Purpose: It is well established that skeletal muscle ischemia followed by reperfusion induces oxidative damage, metabolic stress, and an inflammatory response. This ischemia-reperfusion injury has been studied extensively in experimental models and, importantly, in the clinical setting where it is associated with tourniquet (TQ) inflation during orthopedic trauma surgery. Of particular clinical concern is the notion that reperfusion upon TQ release is central to oxidative injury, since release necessarily follows surgery. Consequently, the effects of ischemia alone, without reperfusion, is poorly documented. That is, it remains unknown what are the effects of muscle ischemia, per se, on muscle properties that could influence functional recovery postoperatively or what preventative measures might be taken to minimize the potentially deleterious effects of the ischemic period alone. Hence the purpose of this study was to investigate changes in myofibrillar contractile protein oxidation over the course of TQ-induced leg muscle ischemia during orthopedic trauma surgery. Method: Among patients with unilateral ankle fractures requiring surgery at our institution, 24 subjects gave informed consent to participate. All subjects underwent standard general anesthesia. PRE surgical biopsies were collected from the peroneus tertius muscle (PT) immediately after TQ inflation and incision of the skin and underlying connective tissue. POST surgical biopsies were collected from the same muscle immediately before TQ release. Oxidation of PT myosin, actin, and total protein was quantified using Western blot analysis for 4-hydroxynonenal (4-HNE) modified proteins. Results are reported as mean ± standard deviation. Results: Total TQ time ranged from about 21 to 84 min (50.5±16). As anticipated, in PRE biopsies compared to POST biopsies there were large increases in the PT content of 4-NE modified myosin (174.4±128%; P< 1×10-6), actin (223.7±182%; P< 5×10-9), and total protein (567.5±378%; P< 5×10-7). Intriguingly, there was a much greater increase in PT protein oxidation in males than in females (43.3% difference; P< 0.05), although there was no relationship observed between PT protein oxidation and subject age. Surprisingly, there was no significant relationship between muscle protein oxidation and duration of the TQ-induced ischemia. Conclusion: TQ-induced skeletal muscle ischemia for 21 to 84 min during orthopedic trauma surgery leads to considerable oxidative muscle injury as measured by muscle protein oxidation, including of the functionally relevant contractile proteins myosin and actin. This injury occurs even without reperfusion. Interestingly, the extent of oxidative muscle injury appears to be influenced by gender, but is not dependent upon the duration of ischemia. FUNDING: MSFHR, COF, BCLA

Background: Scientific investigation of muscle trauma and regeneration is in need of well standardised models. These should mimic the clinical situation and be thoroughly described histologically and functionally. Existing models of blunt muscle injury are either based on segmental muscle damage or in case of whole muscle injury also affect the innervating structures. In this study we present a modified model of open crush injury to the whole soleus muscle of rats sparing the region of the neuromuscular junctions. Methods: The left soleus muscles of male Sprague-Dawley rats were crushed with the use of a curved artery forceps. Functional regeneration was evaluated 1, 4 and 8 weeks after trauma (n = 6 per group) via in vivo measurement of muscle contraction force after fast twitch and tetanic stimulation of the sciatic nerve. The intact right soleus muscle served as an internal control. H & E staining was used for descriptive analysis of the trauma. The amount of fibrosis was determined histomorphologically on Picro-Sirius Red stained sections at each point of time. Results: Across the evaluated regeneration period a continuous increase in contraction force after fast twitch as well as after tetanic stimulation could be observed – describing the functional regeneration of the traumatized soleus muscle over time. Tetanic force amounted to 0.34 ± 0.14 N, which are 23 ± 4% of the control side one week after trauma, and recovered to 55 ± 23% after eight weeks. Fast twitch contraction was reduced to 49 ± 7% of the control side at one week after injury and recovered to 68 ± 19% during the study period. Fibrotic tissue occupied 40 ± 4% of the traumatized muscles after the first week, decreased to approximately 25% after four weeks and remained at this value at eight weeks. Conclusion: The trauma model characterised morphologically and functionally in the presented study allows the investigation of muscle regeneration caused by highly standardized injury exclusively to muscle fibers

Introduction: The complexity of the spine has made a complete understanding of its mechanical function difficult. As a consequence, biomechanical models have been used to describe the behaviour of the spine and its various components. A comprehensive mathematical model of the muscles of the lumbar spine and trunk is presented to enable computation of the forces and moments experienced by the lumbar intervertebral joints during physiological activities. Methods: The model includes the nine major muscles crossing the region and concentrates on improving the estimated line of action for the muscles. The muscles are considered to consist of numerous fascicles, each with its own force producing potential based on size and line of action. The model respects the physical constraints imposed by the skeletal structure by ensuring that muscles maintain their anatomical position in various spinal postures. Validation was performed by comparing model predictions of maximum moments to published data from maximum isometric exertions in male volunteers. To highlight the potential novel uses of the model, three examples of muscle injury caused by surgical procedures were investigated; posterior lumbar surgery, impairment of abdominal muscles from anterior surgery and removal of the psoas major unilaterally during total hip replacement. Results: The validation indicated that the model predicted forces similar to those measured in normal volunteers. The biomechanical changes resulting from the muscle injuries during the surgical procedures share several common features: decreased spinal compression and production of asymmetric moments during symmetric tasks. Discussion: The results suggest that interference with muscles crossing or attaching to the lumbar spine can have a significant impact on its function

The June 2012 Research Roundup. 360. looks at: platelet-rich plasma; ageing, bone and mesenchymal stem cells; cytokines and the herniated intervertebral disc; ulcerative colitis, Crohn’s disease and anti-inflammatories; the effect of NSAIDs on bone healing; osteoporosis of the fractured hip; herbal medicine and recovery after acute muscle injury; and ultrasound and the time to fracture union

INTRODUCTION: The complexity of the spine has made a complete understanding of its mechanical function difficult. As a consequence, biomechanical models have been used to describe the behaviour of the spine and its various components. A comprehensive mathematical model of the muscles of the lumbar spine and trunk is presented to enable computation of the forces and moments experienced by the lumbar intervertebral joints during physiological activities. METHODS: The model includes the nine major muscles crossing the region and concentrates on improving the estimated line of action for the muscles. The muscles are considered to consist of numerous fascicles, each with its own force producing potential based on size and line of action. The model respects the physical constraints imposed by the skeletal structure by ensuring that muscles maintain their anatomical position in various spinal postures. Validation was performed by comparing model predictions of maximum moments to published data from maximum isometric exertions in male volunteers. To highlight the potential novel uses of the model, three examples of muscle injury caused by surgical procedures were investigated; posterior lumbar surgery, impairment of abdominal muscles from anterior surgery and removal of the psoas major unilaterally during total hip replacement. RESULTS: The validation indicated that the model predicted forces similar to those measured in normal volunteers. The biomechanical changes resulting from the muscle injuries during the surgical procedures share several common features: decreased spinal compression and production of asymmetric moments during symmetric tasks. DISCUSSION: The results suggest that interference with muscles crossing or attaching to the lumbar spine can have a significant impact on its function

Aims

This study explored the shared genetic traits and molecular interactions between postmenopausal osteoporosis (POMP) and sarcopenia, both of which substantially degrade elderly health and quality of life. We hypothesized that these motor system diseases overlap in pathophysiology and regulatory mechanisms.

Aims

Rotator cuff (RC) injuries are characterized by tendon rupture, muscle atrophy, retraction, and fatty infiltration, which increase injury severity and jeopardize adequate tendon repair. Epigenetic drugs, such as histone deacetylase inhibitors (HDACis), possess the capacity to redefine the molecular signature of cells, and they may have the potential to inhibit the transformation of the fibro-adipogenic progenitors (FAPs) within the skeletal muscle into adipocyte-like cells, concurrently enhancing the myogenic potential of the satellite cells.

Scar tissue formation secondary to acute muscle injury, surgical wounding and compartment syndrome can result in significant functional impairment and predispose to further injury. The source of fibroblasts, and the molecular mechanisms driving their activation and persistence in skeletal muscle fibrosis are not known. We hypothesized that cells expressing PDGFRβ become fibroblasts in response to injury and that targeting αv integrins in these cells reduces skeletal muscle fibrosis. We used double-fluorescent reporter mice to demonstrate that cells expressing PDGFRβ become activated myofibroblasts in response to cardiotoxin (CTX) induced skeletal muscle injury. Following injury, PDGFRβ+ cells moved from perivascular locations into the interstitium in a distribution characteristic of fibroblasts, and showed marked induction of fibroblastic genes including αSMA and collagen1 (all p<0.0001). To confirm that αv integrins present on PDGFRβ cells critically regulate skeletal muscle fibrosis we used Itgavflox/flox;PDGFRβ-Cre mice (transgenic mice in which αv integrins are ‘knocked-down’ in PDGFRβ+ cells). These mice were significantly protected from CTX induced fibrosis (p<0.01). To demonstrate potential clinical utility of targeting αv integrins, we used a small molecule inhibitor of αv integrins (CWHM12). Treatment with CWHM12 significantly reduced fibrosis when delivered from the time of injury (p<0.01) and when delivered after the fibrotic response had become established (p<0.01). We have identified a core pathway regulating fibrosis in skeletal muscle. Pharmacologic inhibition of αv integrins has potential clinical utility in the treatment and prevention of skeletal muscle fibrosis

Aims

The decrease in the number of satellite cells (SCs), contributing to myofibre formation and reconstitution, and their proliferative capacity, leads to muscle loss, a condition known as sarcopenia. Resistance training can prevent muscle loss; however, the underlying mechanisms of resistance training effects on SCs are not well understood. We therefore conducted a comprehensive transcriptome analysis of SCs in a mouse model.

The approach to total hip arthroplasty (THA) should allow adequate visualization and access so as to implant in optimal position whilst minimizing muscle injury, maintaining or restoring normal soft tissue anatomy and biomechanics and encouraging a rapid recovery with minimal complications. Every surgeon who performs primary hip arthroplasties will expound the particular virtues of his or her particular routine surgical approach. Usually this approach will be the one to which the surgeon was most widely exposed to during residency training. There is a strong drive from patients, industry, surgeon marketing campaigns, and the media to perform THA through smaller incisions with quicker recoveries. The perceived advantage of the anterior approach is the lack of disturbance of the soft tissues surrounding the hip joint, less pain, faster recovery with the potential for earlier return to work, shorter hospital stay and improved cosmetic results. The potential disadvantages include less visibility, longer operation time, nerve injuries, femoral fractures, malposition and a long learning curve for the surgeon (and his / her patients). The anterior approach was first performed in Paris, by Robert Judet in 1947. The advantages of the anterior approach for THA are several. First, the hip is an anterior joint, closer to the skin anterior than posterior. Second, the approach follows the anatomic interval between the zones of innervation of the superior and inferior gluteal nerves lateral and the femoral nerve medial. Third, the approach exposes the hip without detachment of muscle from the bone. The mini-incision variation of this exposure was developed by Joel Matta in 1996. He rethought his approach to THA and his goals were: lower risk of dislocation, enhanced recovery, and increased accuracy of hip prosthesis placement and leg length equality. This approach preserves posterior structures that are important for preventing dislocation while preserving important muscle attachments to the greater trochanter. The lack of disturbance of the gluteus minimus and gluteus medius insertions facilitates gait recovery and rehabilitation, while the posterior rotators and capsule provide active and passive stability and account for immediate stability of the hip and a low risk of dislocation. A disadvantage of the approach is the fact that a special operating table with traction is required. Potential complications include intraoperative femoral and ankle fractures. These can be avoided through careful manipulation of the limb. If a femoral fracture occurs, the incision can be extended distally by lengthening the skin incision downward along the anterolateral aspect of the thigh, and splitting the interval between the rectus femoris and the vastus lateralis. The choice of approach used to perform a primary THA remains controversial. The primary goals are pain relief, functional recovery and implant longevity performed with a safe and reproducible approach without complications. The anterior approach is promising in terms of hospital stay and functional recovery. Although recent studies suggest that component placement in minimally invasive surgery is safe and reliable, no long-term results have been published. Further follow-up and development is necessary to compare the results with the posterior approach as most of the positive data is based on comparisons with the anterolateral approach. The proposed benefits of the anterior approach are not supported by the current available literature. The issues regarding the difficult learning curve, rate of complications, operative time, requirement for trauma tables and image intensifier should be taken into account by surgeons starting with the anterior approach in THA

The approach to total hip arthroplasty (THA) should allow adequate visualization and access so as to implant in optimal position whilst minimizing muscle injury, maintaining or restoring normal soft tissue anatomy and biomechanics and encouraging a rapid recovery with minimal complications. The direct anterior approach (DAA) for THA was first performed in Paris, by Robert Judet in 1947. This procedure has since been performed consistently by a small group of surgeons and has recently gained great popularity. Access to the hip can be safely performed with one or two assistants. The advantages of the anterior approach for hip arthroplasty are several. First, the hip is an anterior joint, closer to the skin anterior than posterior. Second, the approach follows the anatomic interval between the zones of innervation of the superior and inferior gluteal nerves lateral and the femoral nerve medial. Third, the approach exposes the hip without detachment of muscle from the bone. Care must be taken to avoid cutting the lateral femoral cutaneous nerve which runs over the fascia of the sartorius. The mini-incision variation of this exposure was developed by Joel Matta in 1996. He rethought his approach to hip arthroplasty and by abandoning the posterior approach and adopting the anterior approach his goals were: lower risk of dislocation, enhanced recovery, and increased accuracy of hip prosthesis placement and leg length equality. This approach preserves posterior structures that are important for preventing dislocation while preserving important muscle attachments to the greater trochanter. The lack of disturbance of the gluteus minimus and gluteus medius insertions facilitates gait recovery and rehabilitation while the posterior rotators and capsule provides active and passive stability and accounts for immediate stability of the hip and a low risk of dislocation. Using the anterior approach, patients are allowed to mobilise their hip freely. The gluteus maximus and tensor fascia latae muscles insert on the iliotibial band which joins them and form a ´hip deltoid´. Lack of disturbance of these abductors and pelvic stabilisers is another benefit of the anterior approach and accelerates gait recovery. The lateral femoral cutaneous nerve is at risk when the fascia is incised between the tensor fascia latae and the sartorius muscle. Damaging it may lead to a diminished sensation on the lateral aspect of the thigh and formation of a neuroma. A disadvantage of the approach is the fact that a special operating table with traction is required. Potential complications include intra-operative femoral and ankle fractures. These can be avoided through careful manipulation of the limb. If a femoral fracture occurs, the incision can be extended distally along the anterolateral aspect of the thigh, and splitting the interval between the rectus femoris and the vastus lateralis. In obese or muscular patients, where visibility is in doubt, an increase of the incision length will give the surgeon the required view. The choice of approach used to perform a primary THA remains controversial. The primary goal of a hip replacement is pain relief, functional recovery and implant longevity performed with a safe and reproducible approach without complications. The anterior approach is promising in terms of hospital stay and functional recovery. Although recent studies suggest that component placement in minimally invasive surgery is safe and reliable, no long-term results have been published. Further follow-up and development is necessary to compare the results with the posterior approach. The proposed benefits of with the DAA are not supported by the current available literature. The issues regarding the difficult learning curve, rate of complications, operative time, requirement for trauma tables and image intensifier should be taken into account by surgeons starting with the DAA in THA

Significance. Acute compartment syndrome (ACS) occurs after muscle injury and is characterised by increased pressure in the muscle compartment that can result in devastating complications if not diagnosed and treated appropriately. ACS is currently confirmed by repeated needle sticks to measure the compartment pressure using a hand-held compartment pressure monitor. This approach is often not reproducible and is not appropriate for continuous monitoring. To address the shortcomings of currently available technology we are developing an implantable micro-device that will measure compartment pressure directly and continuously over the 24 hours critical period following injury using a radio frequency identification (RFID) platform integrated with a MEMS capacitive pressure sensor. Methods. The prototype implantable device measuring 3mmx3mm consists of a capacitive pressure sensor, a sensor readout circuitry, an antenna and a radio frequency reader. A prototype sensor was packaged in Silicone gel (MED-6640, Nusil Technology LLC) for ex vivo and in vivo testing in three compartment models. First, it was tested ex vivo in an airtight vessel using a blood pressure monitor to pump air and increase the pressure inside the vessel. Second, it was implanted in a muscle compartment of a fresh porcine hind limb and an infusion pump with normal saline was used to raise the tissue pressure. Third, it was implanted in the posterior thigh muscle of a rat where the pressure was increased by applying a tourniquet around the thigh. The readings were compared with those from a hand-held Stryker Intra-compartmental Pressure Monitor System used in the trauma room. Results. The sensor reading from the radio frequency reader software interface in all three models showed good linearity against the pressure applied to the compartment. Conclusion. The successful completion of this project will lead to the development of an implantable miniaturised wireless pressure sensor microsystem capable of measuring tissue compartment pressures in the critical period after traumatic injury and reduce the incidence of serious complications such as severe pain, paralysis, sensory deficits, muscle necrosis and permanent disability

Hip and groin injuries are common in athletes who take part in high level sports. Adductor muscle tendon injuries represent a small but important number of these injuries. Avulsion of the tendons attached to the symphysis pubis has previously been described: these can be managed both operatively and non-operatively. We describe an uncommon variant of this injury, namely complete avulsion of the adductor sleeve complex: this includes adductor longus, pectineus and rectus abdominis. We go on to describe a surgical technique which promotes a full return to the pre-injury level of sporting activity. Over a period of ten years, 15 high-level athletes with an MRI-confirmed acute adductor complex avulsion injury (six to 34 days old) underwent surgical repair. The operative procedure consisted of anatomical re-attachment of the avulsed tissues in each case and mesh reinforcement of the posterior inguinal wall in seven patients. All underwent a standardised rehabilitation programme, which was then individualised to be sport-specific. One patient developed a superficial wound infection, which was successfully treated with antibiotics. Of the 15 patients, four complained of transient local numbness which resolved in all cases. All patients (including seven elite athletes) returned to their previous level of participation in sport. Cite this article: Bone Joint J 2015;97-B:1488–92

A 7-day randomised controlled pre-clinical trial utilising an existing extremity war wound model compared the efficacy of saline soaked gauze to commercially available dressings. The Flexor Carpi Ulnaris of anaesthetised rabbits was exposed to high-energy trauma using a computer-controlled jig and inoculated with 10. 6. Staphylococcus aureus 3 hours prior to application of dressing. Quantitative microbiological assessment demonstrated reduced bacterial counts in INADINE (Iodine) and ACTICOAT (Nanocrystalline Silver) groups and an increase in ACTIVON TULLE (Manuka Honey) group (2-way ANOVA p<0.05). Clinical observations were made throughout the study. Haematology and plasma cytokines were analysed at intervals. Post-mortem histopathology included subjective semi-quantitative assessment of pathology severity using light microscopy to grade muscle injury and lymph node activation. Tissue samples were also examined using scanning electron microscopy (SEM). There were no bacteraemias, abscesses, purulent discharge or evidence of contralateral axillary lymph node activation. There were no significant differences in animal behaviour, weight change, maximum body temperature or white blood cell count elevation nor in pathology severity in muscle or lymph nodes (Kruskal-Wallis). There was no evidence of bacterial penetration or biofilm formation on SEM. Interleukin-4 and Tumour Necrosis Factor α levels were significantly higher in the ACTIVON TULLE group (1-way ANOVA p<0.05). This time-limited study demonstrated a statistically significant reduction in Staphylococcus aureus counts in wounds dressed with INADINE and ACTICOAT and an increase in wounds dressed with ACTIVON TULLE. There was no evidence that any of these dressings cause harm but nor have we established any definite clinical advantage associated with the use of the dressings tested in this study

The effect of cortisone on the repair of simple muscle injury was studied in rabbits. The histological findings in the crushed muscle are described for a period up to twenty-one days after injury. Cortisone defers the onset of muscle regeneration, and retards its progress, but it does not change the course of the repair process or alter its eventual outcome under the conditions of the experiment. This apparent refractoriness of repair of muscle, as compared with that of other connective tissues, is discussed

Aims

The aim of this study was to prepare a scoping review to investigate the use of biologic therapies in the treatment of musculoskeletal injuries in professional and Olympic athletes.

Aims. A new therapy, based on the intra-articular injection of autologous conditioned serum (ACS), is used in several European countries for osteoarthritis (OA) treatment. ACS is generated by incubating venous blood with medical grade glass beads. Peripheral blood leukocytes produce elevated amounts of endogenous anti-inflammatory cytokines such as interleukin-1 receptor antagonist (IL-1Ra) and growth factors that are recovered in the serum(1). ACS has been shown to improve the clinical lameness in horses significantly to enhance the healing of muscle injuries in animal models, and in human athletes. In the present study, the efficacy and safety of ACS was compared to intra-articular hyaluronan (HA), and saline in patients with confirmed knee OA. Methods. In a prospective, randomised, patient- and observer-blind trial with three parallel groups, 376 patients with knee OA were included in an intention to treat (ITT-) analysis. Efficacy was assessed by patient-administered outcome instruments (WOMAC, VAS, SF-8, GPA) after 7, 13 and 26 weeks (blinded) and Two-years (non-blinded). The frequency and severity of adverse events were used as safety parameters. Results. In all treatment groups, intra-articular injections produced a significant reduction in WOMAC-scores and weight-bearing pain (VAS). However, responses to ACS were stronger. The superiority of ACS and either HA or saline was statistically significant for all outcome measures and time points. No significant differences between HA treatment and saline injections (p>0.05, at all time points and outcome measures) were recorded. Frequency of adverse advents (AE) was comparable in the ACS- and the saline-group (p>0.05). Conclusion. The results demonstrate that ACS is effective, long-lasting and well tolerated in the management of chronic, idiopathic OA of the knee. So far, the efficacy of ACS is defined through improvement in clinical signs and symptoms, particularly pain. It remains to be determined whether they are disease-modifying, chondroprotective, or even chondroregenerative, sequelae

Introduction. There is a challenge to detect partial tear of the ACL, the number of bundle injured and the proportion of fibers torn. The MRI was shown efficient to individualize the two anteromedial (AM) and posterolateral (PL) bundles of the ACL. The purpose of this study was to assess the ability of the MRI to detect partial tears of the ACL on axial views to display the AM and PL bundles. Materials and methods. This retrospective study included 48 patients (19 partial tears of the ACL, 16 complete rupture of the ACL and 13 normal knee) who underwent both arthroscopy and MRI examinations of the knee. The conventional MRI protocol included one sagittal T1- weighted sequence and 3 proton-density fat sat. The images from MRI were analysis by a radiologist specialized in musculoskeletal imaging who was blinding to the arthroscopic findings. The criteria for the analysis of MRI were divided into primary (those involving the ACL himself) and secondary signs (associated abnormalities). The primary signs included the horizontalisation of the ACL (ACL axis), the global ACL signal intensity and the signal intensity of each AM and PL bundle. The secondary signs included bone bruise, osteochondral impaction, popliteus muscle injury, medial collateral ligament injury and joint effusion. The ACL was classified as normal, partially or totally torn. The rupture of the AM and PL bundle was specified. Results. In our study, MRI was found to have a 75% sensitivity and a 73% specificity for the diagnosis of partial tears of the ACL. The sensitivity to detect AM bundle lesion was 88% but the specificity was 50%. The lack of horizontalisation of the ACL was a very good sign, for partial tears of the ACL, with a sensitivity of 84% and a specificity of 81% (p<0.05). Regarding the secondary signs, there was no significant difference to distinguish partial and complete tear. However, we found that there was a greater probability to find a partial tear of the ACL with the lack of joint effusion, bone bruise and medial collateral ligament injury. Quantifying the proportion of injured fibers was unsuccessful and was found as a failure of the MRI. Conclusions. MRI exhibited lower sensitivity and specificity for partial tear than for complete rupture of the ACL. However 3 important arguments can guide us: the lack of horizontalisation of the ACL, a continuous ACL signal, the display of one of two bundles on the axial view

Injuries to the hamstring muscle complex are common in athletes, accounting for between 12% and 26% of all injuries sustained during sporting activities. Acute hamstring injuries often occur during sports that involve repetitive kicking or high-speed sprinting, such as American football, soccer, rugby, and athletics. They are also common in watersports, including waterskiing and surfing. Hamstring injuries can be career-threatening in elite athletes and are associated with an estimated risk of recurrence in between 14% and 63% of patients. The variability in prognosis and treatment of the different injury patterns highlights the importance of prompt diagnosis with magnetic resonance imaging (MRI) in order to classify injuries accurately and plan the appropriate management.

Low-grade hamstring injuries may be treated with nonoperative measures including pain relief, eccentric lengthening exercises, and a graduated return to sport-specific activities. Nonoperative management is associated with highly variable times for convalescence and return to a pre-injury level of sporting function. Nonoperative management of high-grade hamstring injuries is associated with poor return to baseline function, residual muscle weakness and a high-risk of recurrence. Proximal hamstring avulsion injuries, high-grade musculotendinous tears, and chronic injuries with persistent weakness or functional compromise require surgical repair to enable return to a pre-injury level of sporting function and minimize the risk of recurrent injury.

This article reviews the optimal diagnostic imaging methods and common classification systems used to guide the treatment of hamstring injuries. In addition, the indications and outcomes for both nonoperative and operative treatment are analyzed to provide an evidence-based management framework for these patients.

Cite this article: Bone Joint J 2020;102-B(10):1281–1288.

Injury to muscles is very common. We have previously observed that basic fibroblast growth factor (b-FGF), insulin growth factor type 1 (IGF-1) and nerve growth factor (NGF) are potent stimulators of the proliferation and fusion of myoblasts in vitro. We therefore injected these growth factors into mice with lacerations of the gastrocnemius muscle. The muscle regeneration was evaluated at one week by histological staining and quantitative histology. Muscle healing was assessed histologically and the contractile properties were measured one month after injury. Our findings showed that b-FGF, IGF and to a less extent NGF enhanced muscle regeneration in vivo compared with control muscle. At one month, muscles treated with IGF-1 and b-FGF showed improved healing and significantly increased fast-twitch and tetanus strengths. Our results suggest that b-FGF and IGF-1 stimulated muscle healing and may have a considerable effect on the treatment of muscle injuries

Compartment syndrome is a unique form of ischaemia of skeletal muscle which occurs despite patency of the large vessels. Decompression allows the influx of activated leucocytes which cause further injury. Vitamin C is a powerful antioxidant which concentrates preferentially in leucocytes and attenuates reperfusion-induced muscle injury. We have evaluated the use of pretreatment with oral vitamin C in the prevention of injury caused by compartment syndrome in a rat cremasteric muscle model. Acute and delayed effects of pretreatment with vitamin C were assessed at one and 24 hours after decompression of compartment syndrome. Muscle function was assessed electrophysiologically. Vascular, cellular and tissue inflammation was assessed by staining of intercellular adhesion molecule-1 (ICAM-1) and by determination of the activity of myeloperoxidase (MPO) in neutrophils and tissue oedema. Compartment syndrome impaired skeletal muscle function and increased the expression of ICAM-1, activity of MPO and muscle weight increased significantly. Pretreatment with vitamin C preserved muscle function and reduced the expression of ICAM-1, infiltration of the neutrophils and oedema

MicroRNAs (miRNAs) are a class of small non-coding RNAs that have emerged as potential predictive, prognostic, and therapeutic biomarkers, relevant to many pathophysiological conditions including limb immobilization, osteoarthritis, sarcopenia, and cachexia. Impaired musculoskeletal homeostasis leads to distinct muscle atrophies. Understanding miRNA involvement in the molecular mechanisms underpinning conditions such as muscle wasting may be critical to developing new strategies to improve patient management. MicroRNAs are powerful post-transcriptional regulators of gene expression in muscle and, importantly, are also detectable in the circulation. MicroRNAs are established modulators of muscle satellite stem cell activation, proliferation, and differentiation, however, there have been limited human studies that investigate miRNAs in muscle wasting. This narrative review summarizes the current knowledge as to the role of miRNAs in the skeletal muscle differentiation and atrophy, synthesizing the findings of published data.

Cite this article: Bone Joint Res 2020;9(11):798–807.

Aims: Acute lateral dislocation of the patella has been associated with disruption of the medial restraints of the patella and following non-operative management, a redislocation rate of up to 44%. Methods: Ten patients who presented to the Accident and Emergency dept. following acute patella dislocation had an ultrasound scan (USS) performed by an experienced musculoskel-etal radiologist. Each patient had an arthroscopy and washout of the knee and repair of ruptured structures. The ultrasound reports have now been compared to the surgical findings to determine the effectiveness of this investigation. Results: The ultrasound scans identified deficiencies in the ligamentous attachments to the medial border of the patella in eight patients and these were confirmed at operation in the same eight. The USS diagnosis of haematoma or torn fibres in the vastus medialis obliquus (VMO) (5 patients) corresponded with tearing of this muscle at operation; however the degree of muscle injury was underestimated in two. The USS finding of free fluid around the medial collateral ligament (MCL) at the adductor tubercle in three patients was associated with the operative finding of disruption of the femoral origin of the medial patellofemoral ligament (MPFL). Haematomata detected on USS along the adductor longus in two patients proved to have disruption of the VMO attachment. Conclusions: We recommend the use of ultrasound for assessment of all patella dislocations to accurately locate tears of the retinaculum and help clinicians to understand the severity of injury to the soft tissue restraints of the patella

Traumatic uraemia is of particular significance to orthopaedic surgeons in so far as this complication is responsible for high mortality in cases of severe injury, crushing injury, traumatic shock, gun-shot wounds, incompatible blood transfusions, and the misuse of tourniquets. In this contribution the association between muscle injury and renal failure is reviewed. The syndrome of the "crush kidney," which at first was thought to be the result of deposition of myohaemoglobin in the renal tubules, is almost certainly due to the association of many factors, all of which lead to alteration of the renal circulation and renal ischaemia. Certainly the combination of ischaemia of the kidney with deposition of pigment and haemolysis of blood causes a high mortality in animals, and it is believed that this may account for the serious prognosis in human cases where there is both shock and haemolysis. Disturbance of water balance, allergic phenomena, and chemical nephrotoxic action are also discussed. The pathology is considered together with significant changes in the blood chemistry. A plea is made for early recognition of this clinical syndrome with its characteristic features. Important aspects of treatment are discussed. The dangers of excessive intravenous infusion are emphasised. Closer investigation and further research promise to throw light on the more accurate localisation of function in the nephron, to add to our knowledge of traumatic arterial spasm, and to explain many orthopaedic problems which hitherto appeared insoluble

Crown copyright 2009. Published with the (permission of the Defence Science and Technology Laboratory on behalf of the Controller of HMSO. Introduction. The optimum strategy for the care of war wounds is yet to be established. A need exists to model complex extremity injury, allowing investigation of wound management options. Aim. To develop a model of militarily relevant extremity wounding. Study Design. Laboratory study with New Zealand White Rabbits. Methods. Phase 1. Development of injury. Following induction of general anaesthesia, a muscle belly on the flexor aspect of the forelimb of the rabbit was exposed. This was achieved by creating a fascial tunnel under the belly of flexor carpi ulnaris (FCU). Utilising a custom built drop test rig a high energy, short duration impact was delivered. To replicate casualty evacuation timelines, the animal was maintained under anaesthesia for three hours and recovered. The wound was dressed with saline soaked gauze and supportive bandaging. 48 hrs later, the animal was culled and the muscle harvested for histological analysis. Analgesia was administered once a day. Animals were checked by experienced staff at least twice a day and body temperature recorded by a subcutaneous transponder. Phase 2. Contamination of muscle injury. Sequential animals had inoculums of 1×102/100μl, 1×106/100μl and 1×108/100μl of Staphylococcus aureus administered to the muscle immediately after injury. Animals were recovered from anaesthetic and monitored as per phase 1. Delivery was evaluated by droplet spread and via injection by fine bore needle into the muscle belly. At the 48 hour point, the animals were culled, dressings removed, the muscle harvested and auxiliary lymph nodes sampled. Quantitative microbiological analysis was performed to determine colony forming unit counts (CFU) at 24 hours post-collection. Results. Phase 1. Six animals were exposed to a loading of 0.5kg. Histological analysis demonstrated a consistent injury pattern with 20% of the muscle belly becoming necrotic. Following discussion with subject matter experts this was found to be representative of the nature of injury from ballistic limb trauma and was adopted as standard. Phase 2. Twenty-two animals were exposed to the standardised injury and then inoculated at the prescribed challenge doses and delivery methods. A challenge dose of 1×106/100μl S. aureus delivered by droplet provided the greatest consistency. A group of six animals with an average challenge dose of 3.3×106/100μl yielded growth at 48hrs on average of 9.2×106 CFU. There were no adverse effects on animal welfare throughout, with body temperatures within normal limits at all times. Discussion. The use of rabbits in the investigation of musculoskeletal injury and infection is well established. No study to date however has addressed high energy complex soft tissue wounding, contamination and its optimum management. Considering the current burden of such wounds the need for this question to be answered in a research setting is transparent. This model enables a significant, reproducible, contaminated soft tissue injury to be delivered in vivo. It will allow the investigation of complex wound management options including wound coverage and fracture fixation

Introduction: In 1971, Cloward wrote that after anterior cervical surgery, dysphagia occurs in all patients and is due to pressure on the oesophagus by the retractors. Recent studies indicate that dysphagia occurs in 54% of patients at 1 month and 13.6 % at 2 years. Recurrent laryngeal nerve injury occurs in 15 – 23 % producing hoarseness in one third of these. The continuing frequency of these complications even in experienced hands suggests that a review of retractor design and consideration of new designs is worthwhile. Methods: A Medline search of unlimited years in English using terms: retractors, surgical instruments, development and history was performed. Described retractors and their design principles were reviewed and a novel principle identified from which an anterior cervical device was developed and tested. Results: The novel general principle states that superior retraction is achieved by combining fixation onto bone with variable rotation of the retractor blade. Bone stabilization within the wound provides optimal stability and mechanical advantage for retraction while variable rotation allows retraction or tissue relaxation. Excluding the ubiquitous handheld retractors which lack stability, 7 different designs of anterior cervical retractors have been described. Anecdotally self retaining retractors are the most commonly used, but to be stable they require equal bilateral tissue counterforce and tissues that do not stretch. They are thus doubly ill suited for the asymmetrical anterior approaches to the anterior cervical spine. In the new anterior cervical retractor a small internal frame is fixed to the spine using standard Caspar screws. The frame slides with distraction. Routine surgery including plating is carried out within the frame. The frame provides stable axes for the independently rotating medial and lateral retractor blades. Discussion: In the spine intermittent relaxation of retraction has recently been shown to reduce muscle injury and pain after lumbar surgery. This is the first retractor system that can be released without sacrificing stability or exposure. Despite numerous authors implicating cervical retractors as a source of complications there are few investigations and no studies investigating different designs. Rather than accepting or denying common complications we should investigate even our most familiar tools

Background and Objectives. There are various classifications to assess the degree of open fracture and each has it’s own advantages and disadvantages. We proposed a new system since we couldn’t find any which was simple, objective, reliable, reproducible and applicable in an emergency setting. We set five variables namely, skin break, bone damage, muscle injury, neurovascular impairment and the degree of contamination to make scoring. We needed to know if the proposed classification had a better reliability, was simple, objective and applicable. Design and Setting. A proposed diagnostic testing was set to better classifying the degree and severity open fractures. Every patient with open lower leg fracture was classified with the proposed Sardjito Scoring System. The residents on duty, medical students and nurse staffs were then asked to classify them with the proposed scoring Gustilo system . The debridement reports were used to be the standard as a comparison of the classification made by the residents, medical student and nurse staffs. Main Outcome Measurements. The classifications made by the residents, medical students and nurses were compared with the finding during the debridement to measure their reliability with kappa coefficient, sensitivity, specivity and accuracy. Results. We had 40 patients with open lower leg fracture. We found exelent reliability among the residents, medical students, and nurses (k: 0.86 p: 0.000). Conclusion. The proposed Sardjito Scoring system of the open lower leg fracture was so far reliable, making it reproducible and applicable

Background: Traumatic dislocations of the knee are uncommon (< 1% of all dislocations), but they account to the most serious ligament and soft tissue injuries of the knee. Diagnosis and treatment of the dislocated knee present a major challenge to the orthopaedic surgeon. The purpose of our retrospective study was to critically analyze the clinical outcome of all traumatic knee dislocations treated operatively between 1996 and 2006 in our institution. Methods: Retrospective clinical case series study of all patients treated for traumatic knee dislocation (m: w=12:4; mean age 31 yrs, range 17–63 yrs) from 1998–2006. The mechanism of injury was a traffic accident (n=7), a sport trauma (n=8) and slip and fall (n=1). The charts of all patients were analyzed. The clinical outcome was assessed by personal telephone interview by a modified SSK questionnaire by Insall. Surgery was performed by one team of surgeons 2–89 days after trauma. Mean and range were reported for continuous variables and relative and absolute frequencies vor categorial variables. Data were analyzed using Stata version 8. The level of significance was defined as p< 0.05. Results: The injury pattern is reported below:. 15 anterior cruciate ligament (ACL) lesions (11x ACL reconstruction), 15 posterior cruciate ligament (PCL) lesions (9x refixation, 3x reconstruction), 13 medial collateral ligament (MCL) lesions (8x reconstruction), 6 medial posterior collateral ligament (MPCL) lesions (4x reconstruction), 4 lateral collateral ligament (LCL) lesions (1x reconstruction), 3 popliteal muscle injuries (2x reconstruction), 5 medial meniscal lesions, 10 lateral meniscal lesions (9x suture, 1x partial meniscectomy), 3 femoral fractures, 1 proximal tibial fracture. One angiography was performed. No vascular lesion was observed. The follow up rate was 93% complete. The mean follow up time was 58 months (range 35–156). 83% of patients were able to return to work without any impairment. 62% of patients returned to the same level of sport activity. 54% of patients were absolutely painfree. Based on a modified SSK score by Insall a mean of 182 points (range 129–200) on a scale with maximum 200 points could be noted. Conclusions: Even though in a orthopaedic clinic specialized in the treatment of knee injuries traumatic knee dislocations remain a demanding therapeutic challenge. A highly specialized, customized and sophisticated treatment strategy of a experienced team of surgeons, nurses and physiotherapists is mandatory for acheivement of optimal functional and subjective outcome

Aims

The primary aim of this study was to compare the postoperative systemic inflammatory response in conventional jig-based total knee arthroplasty (conventional TKA) versus robotic-arm assisted total knee arthroplasty (robotic TKA). Secondary aims were to compare the macroscopic soft tissue injury, femoral and tibial bone trauma, localized thermal response, and the accuracy of component positioning between the two treatment groups.

Purpose: Compartment syndrome (CS) is a unique form of skeletal muscle ischaemia. N-acetyl cysteine (NAC) is an anti-oxidant with beneficial microcirculatory effects. We aim to assess the effect of NAC administration on CS induced muscle injury. Methods: Sprague-Dawley rats (n=6/group) were randomised into Control, CS and CS pre-treated with NAC (0.5g/kg i.p. 1 hr prior to induction) groups. In a post-treatment group NAC was administered upon muscle decompression. Cremasteric muscle was placed in a pressure chamber in which pressure was maintained at diastolic minus 10 mm Hg for 3 hours inducing CS, muscle was then returned to the abdominal cavity. At 24 hours and 7 days post CS contractile function was assessed by electrical stimulation. Myeloperoxidase (MPO) activity were assessed at24-hours. Results: CS injury reduced twitch (50.4 ± 7.7 vs 108.5 ± 11.5, p< 0.001; 28.1 ± 5.5 vs. 154.7 ± 14.1, p< 0.01) and tetanic contraction (225.7 ± 21.6 vs 455.3 ± 23.3, p< 0.001; 59.7 ± 12.1 vs 362.9 ± 37.2, p< 0.01) compared with control at 24hrs and 7 days respectively. NAC pre-treatment reduced CS injury at 24 hours preserving twitch (134.3 ± 10.4 , p< 0.01 vs CS) and tetanic (408.3 ± 34.3, p< 0.01 vs CS) contraction. NAC administration reduced neutrophil infiltration (MPO) at 24 hours (24.6 ± 5.4 vs 24.6 ± 5.4, p< 0.01). NAC protection was maintained at 7 days preserving twitch (118.2 ± 22.9 vs 28.1 ± 5.5, p< 0.01) and tetanic contraction (256.3 ± 37 vs 59.7 ± 12.1, p< 0.01). Administration of NAC at decompression also preserved muscle twitch (402.4 ± 52; p< 0.01 versus CS) and tetanic (402.4 ± 52; p< 0.01 versus CS) contraction, reducing neutrophil infiltration (24.6 ± 5.4 units/g; p< 0.01). Conclusions: |NAC provides extended protection to skeletal muscle against compartment syndrome induced injury by both direct reducing neutrophil mediated tissue toxicity and by reducing neutrophil recruitment to the site of injury

Aims

To describe a new objective classification for open fractures of the lower limb and to correlate the classification with patient-centred outcomes.

Virtual encounters have experienced an exponential rise amid the current COVID-19 crisis. This abrupt change, seen in response to unprecedented medical and environmental challenges, has been forced upon the orthopaedic community. However, such changes to adopting virtual care and technology were already in the evolution forecast, albeit in an unpredictable timetable impeded by regulatory and financial barriers. This adoption is not meant to replace, but rather augment established, traditional models of care while ensuring patient/provider safety, especially during the pandemic. While our department, like those of other institutions, has performed virtual care for several years, it represented a small fraction of daily care. The pandemic required an accelerated and comprehensive approach to the new reality. Contemporary literature has already shown equivalent safety and patient satisfaction, as well as superior efficiency and reduced expenses with musculoskeletal virtual care (MSKVC) versus traditional models. Nevertheless, current literature detailing operational models of MSKVC is scarce. The current review describes our pre-pandemic MSKVC model and the shift to a MSKVC pandemic workflow that enumerates the conceptual workflow organization (patient triage, from timely care provision based on symptom acuity/severity to a continuum that includes future follow-up). Furthermore, specific setup requirements (both resource/personnel requirements such as hardware, software, and network connectivity requirements, and patient/provider characteristics respectively), and professional expectations are outlined. MSKVC has already become a pivotal element of musculoskeletal care, due to COVID-19, and these changes are confidently here to stay. Readiness to adapt and evolve will be required of individual musculoskeletal clinical teams as well as organizations, as established paradigms evolve.

Cite this article: Bone Joint Open 2020;1-6:272–280.

Introduction. Hip and groin injuries are common in athletes participating in high level sports. Adductor muscle tendon injuries represent a small but important number of these injuries. Avulsion injuries involving tendons attaching to the symphysis pubis have previously been described and can be managed both operatively and non-operatively. The aim is to describe a rare variant of this injury; complete avulsion of the adductor sleeve complex including adductor longus, pectineus and rectus abdominus. A surgical technique is then outlined which promotes a full return to pre-injury level of sporting activity. Patients/Materials & Methods. Fifteen high level athletes with an MRI confirmed acute adductor complex avulsion injury (6–34 days) were identified from the institution's sports injury database over a 10 year period. All underwent surgical repair. The operative procedure comprised anatomical attachment of the avulsed tissues in all cases (plus mesh reinforcement of the inguinal wall in 7 patients). All underwent a standard format of rehabilitation which was then individualised to be sport specific. Results. One patient developed a superficial wound infection which was successfully treated with antibiotics. 12 out of 15 patients complained of transient local numbness which resolved in all cases. All patients (including 7 elite athletes) returned to their previous level of participation in sport. Discussion. Injury to the triad of adductor longus, pectineus and rectus abdominus should be considered in athletes presenting with groin pain following forced adduction. All athletes underwent early surgical exploration, previous studies have shown prolonged symptoms in early conservative management. Adductor tenotomy has shown previously acceptable results but may be less suitable in elite athletes with higher functional demands when operative repair has been shown to be successful. Conclusion. Operative repair of acute sleeve avulsion of the adductor complex in high level athletes, followed by sport specific rehabilitation promotes return to previous level of participation in sport

Objectives

Experimental studies indicate that non-steroidal anti-inflammatory drugs (NSAIDs) may have negative effects on fracture healing. This study aimed to assess the effect of immediate and delayed short-term administration of clinically relevant parecoxib doses and timing on fracture healing using an established animal fracture model.

Objectives

The aim of this study was to review the current evidence and future application for the role of diagnostic and therapeutic ultrasound in fracture management.

Introduction: Spondylolysis is amongst the commonest causes of low back pain in the athletic child. We observed increased uptake in the pedicles of the affected segment and a triangular pattern of uptake in the sagittal projection of tomographic studies of fractures of the pars interarticularis. The hypothesis that these observations were specific for fractures of the pars interarticularis was tested in a variety of spinal disorders. Methods:. A retrospective study of 25 young athletes with a variety of spinal disorders was undertaken (17males, 8 females; average age 13.5 years [range: nine to16 years]). The patients were referred from a specialised sports clinic. Back pain was present for an average of four months (Range six weeks to 11 months). All children had planar and tomographic scintigraphic bone scans with special reconstruction. The diagnosis was confirmed by radiological studies and/or response to treatment. Results:. All 15 children with spondylolysis had evidence of increased uptake in the ipsilateral (12/15) or contra-lateral pedicle (3/15). None of the cases of muscle insertion injury, facet joint or disc disease demonstrated this pattern. A triangular shaped pattern of uptake was only seen in the sagittal view of the tomographic studies in patients with fractures of the pars interarticularis. Conclusion:. We have described two unique features of spondylolysis that add to the confidence with which the scintigraphic diagnosis may be made

Clinical Problem: fractures under tension are common injuries and occur when patients are falling on partial flexed limbs under maximal contraction of the extensor muscles. Typical injuries are patella and olecranon. For these fractures the tension belt osteosyntheses is the mainly used procedure. A high complication rate regarding dislocation, bone healing, pain and functional outcome are reported. This is due to the unstable fixation with the tension belt because of the tendon insertion around the bone fragment witch allow secondary loosening of the tension belt under alternating load. This was found allready 1987 by Brill and Hopf in an experimental study. Materials and Methods: To improve stabilisation a new device was developed: the XS (4,5mm diameter) and the XXS nail (3,5mm) witch is locked with threaded wires and a set screw allows fracture compression inside the nail independend from the soft tissues around. Fiber Wire cerclage transversal around the threaded wire ends allow the fixation of additional frontal plane fragments or marginal fragments. Experimental test were performed in a patella sow-bone models and showed superior to tension bel (patella) and Plate fixation/fibula). On the other side the locked nail system allows percutaaneous osteosynthesis of the whole ulna also in shaft, distal fractures and shortening osteotomies. All clinical cases treated with the XS/XXS nail where recorded prospectively and re-examined after 6–12 months. From may 2000 to march 2002 76 patients with olecranon fractures were evaluated. 85% of the olecranon fracture patients could be re-examined. Most patients where treated immediately or after wound healing without splint. Results: the experimental results shows in all XS nail group no gap after alternating load of 250 and 500N and a rigidity a little higher than that of the not osteotomised patellae. In the tension belt groups in all tested patellae visible gaps of 1 to 3 mm occurred. There was no difference between the single and double XS nail Osteosynthesis. 71.7% of all patients with olecranon fractures showed a very good result according to the Murphy score. In 2 part fractures the rate was even 94.7%. Only in the group of more part fractures in 5.9% fair results were found. No patient showed a poor result. The technical possibilities of XS nail osteosynthesis in ulna shaft, distal fractures and shortening osteotomies are presented. Conclusions: the XS nail is a new device witch allows good anatomical reconstruction and stable fixation with immediate functional therapy in all olecranon and ulna fractures

Aims

To evaluate interobserver reliability of the Orthopaedic Trauma Association’s open fracture classification system (OTA-OFC).

Large bone defects remain a tremendous clinical challenge. There is growing evidence in support of treatment strategies that direct defect repair through an endochondral route, involving a cartilage intermediate. While culture-expanded stem/progenitor cells are being evaluated for this purpose, these cells would compete with endogenous repair cells for limited oxygen and nutrients within ischaemic defects. Alternatively, it may be possible to employ extracellular vesicles (EVs) secreted by culture-expanded cells for overcoming key bottlenecks to endochondral repair, such as defect vascularization, chondrogenesis, and osseous remodelling. While mesenchymal stromal/stem cells are a promising source of therapeutic EVs, other donor cells should also be considered. The efficacy of an EV-based therapeutic will likely depend on the design of companion scaffolds for controlled delivery to specific target cells. Ultimately, the knowledge gained from studies of EVs could one day inform the long-term development of synthetic, engineered nanovesicles. In the meantime, EVs harnessed from in vitro cell culture have near-term promise for use in bone regenerative medicine. This narrative review presents a rationale for using EVs to improve the repair of large bone defects, highlights promising cell sources and likely therapeutic targets for directing repair through an endochondral pathway, and discusses current barriers to clinical translation.

Cite this article: E. Ferreira, R. M. Porter. Harnessing extracellular vesicles to direct endochondral repair of large bone defects. Bone Joint Res 2018;7:263–273. DOI: 10.1302/2046-3758.74.BJR-2018-0006.

Background and Hypothesis: High-energy fractures associated with severe soft tissue injury have a significant incidence of delayed or non-union. The soft tissue envelope may adversely contribute to the healing of a fracture, not only in stripping of the periosteal blood supply, development of compartment syndrome or tissue interposition between the bone ends but also in its ability to generate an intense acute inflammatory response. Inflammation is the initiator of healing; in clinical scenarios of impaired inflammation (immune deficiency, NSAIDs, corticosteroids) healing is delayed; interestingly, in injury with excess inflammation (CVA, MI) healing is also delayed. Would the inflammatory response following high-energy fractures contribute beneficially or adversely to the healing of the underlying fracture? Using an in-house murine femoral fracture model which reliably demonstrated features of delayed fracture healing when associated with a severe overlying muscle crush injury we proposed these hypotheses:. That fracture callus with overlying muscle crush would contain raised expression of acute inflammatory cytokines (IL-1β, IL-6 and TNF-α). That application of locally applied blocking antibodies to these inflammatory cytokines might negate excessive cytokine release and modulate fracture healing in this model. Methods: Total RNA was extracted from normal fracture callus (FO) and muscle crush fracture callus (MC) at day 2, day 4 and day 8. Semi-quantitative RT-PCR was used to compare IL-1β, IL-6 and TNF-α mRNA expression. Histomorpometric analysis of ICC stained sections of the FO and the MC groups was used to estimate IL-1β, IL-6 and TNF-α protein expression within the callus. Positively staining areas for the cytokine within the callus were a semi-quantified and compared between groups. Finally, blocking antibodies to IL-1β and TNF-α were injected into MC fracture callus at day 0, 4 and 8. Control MC group had vehicle only injected. Fracture healing was measured using radiological, histomorphological and biomechanical outcome measures. Following a pilot dosing experiment, the effect of blocking antibodies on fracture healing was compared between MC and MC with antibody groups. Results: The MC group IL-1β mRNA expression was significantly higher than FO at day 4 and day 8 (p=0.05). ICC for IL-1β protein expression was higher on day 4 and on day 8 in the MC group, significant at day 8 (p=0.03). TNF-α mRNA expression in the MC group at day 8 was significantly higher than the FO group (p=0.05). ICC for TNF-α protein in the MC group peaked at day 8 and was significantly higher than the FO group (p< 0.03). IL-6 mRNA expression was significantly raised in the MC group at day 4 and 8 compared with the FO group (p=0.05). ICC for IL-6 protein showed significantly increased expression at day 8 in the MC group (p=0.05). The patterns of expression of the mRNA and proteins were similar. Injection of anti-TNF-α antibodies into MC mice caused more new bone formation on day 16 (p=0.03) and day 24 (p=0.06), stiffer calluses at day 24 (p=0.01) and faster fracture gap obliteration at day 16 (p=0.05) and day 24 (p=0.001). IL-1β blockade had slightly less effect, more new bone formationd ay 16 (p=0.01) and day 24 (p=0.03), slightly stiffer (p=0.08), but no significant difference in fracture gap obliteration from controls. Conclusion: The effect of muscle crush around the fracture callus was to increase and prolong the expression of inflammatory cytokines with the callus. The effect of blocking these excessive inflammatory cytokines in our model was to improve fracture healing. Excessive inflammatory cytokines (IL-1β, IL-6, TNF-α) in bone impair new bone production by osteoblasts, inhibit the recruitment and differentiation of mesenchymal precursors and promote osteoclastogenesis. The mechanism of action of blocking antibodies may be due to inhibition of the antiosteogenic effects of these cytokines

Objectives

The aim of this study was to systematically review the literature on measurement of muscle strength in patients with femoroacetabular impingement (FAI) and other pathologies and to suggest guidelines to standardise protocols for future research in the field.

Objectives

Rotator cuff tears are among the most frequent upper extremity injuries. Current treatment strategies do not address the poor quality of the muscle and tendon following chronic rotator cuff tears. Hypoxia-inducible factor-1 alpha (HIF-1α) is a transcription factor that activates many genes that are important in skeletal muscle regeneration. HIF-1α is inhibited under normal physiological conditions by the HIF prolyl 4-hydroxylases (PHDs). In this study, we used a pharmacological PHD inhibitor, GSK1120360A, to enhance the activity of HIF-1α following the repair of a chronic cuff tear, and measured muscle fibre contractility, fibrosis, gene expression, and enthesis mechanics.

Objectives

Rotator cuff tears are among the most common and debilitating upper extremity injuries. Chronic cuff tears result in atrophy and an infiltration of fat into the muscle, a condition commonly referred to as ‘fatty degeneration’. While stem cell therapies hold promise for the treatment of cuff tears, a suitable immunodeficient animal model that could be used to study human or other xenograft-based therapies for the treatment of rotator cuff injuries had not previously been identified.

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

Objectives

Traumatic brachial plexus injury causes severe functional impairment of the arm. Elbow flexion is often affected. Nerve surgery or tendon transfers provide the only means to obtain improved elbow flexion. Unfortunately, the functionality of the arm often remains insufficient. Stem cell therapy could potentially improve muscle strength and avoid muscle-tendon transfer. This pilot study assesses the safety and regenerative potential of autologous bone marrow-derived mononuclear cell injection in partially denervated biceps.

The April 2012 Research Roundup³⁶⁰ looks at who is capable of being an arthroscopist, bupivacaine, triamcinolone and chondrotoxicity, reducing scarring in injured skeletal muscle, horny Goat Weed and the repair of osseous defects, platelet-derived growth factor and fracture healing, the importance of the reserve zone in a child’s growth plate, coping with advanced arthritis, hydroxyapatite and platelet-rich plasma for bone defects, and calcium phosphate and bone regeneration

Injury to the perforating branch of the peroneal artery has not been reported previously as a cause of acute compartment syndrome following soft-tissue injury to the ankle. We describe the case of a 23-year-old male who sustained such an injury resulting in an acute compartment syndrome. In a review of the literature, we could find only five previous cases, all of which gave rise to a false aneurysm which was detected after the acute event.

This review is aimed at clinicians appraising preclinical trauma studies and researchers investigating compromised bone healing or novel treatments for fractures. It categorises the clinical scenarios of poor healing of fractures and attempts to match them with the appropriate animal models in the literature.

We performed an extensive literature search of animal models of long bone fracture repair/nonunion and grouped the resulting studies according to the clinical scenario they were attempting to reflect; we then scrutinised them for their reliability and accuracy in reproducing that clinical scenario.

Models for normal fracture repair (primary and secondary), delayed union, nonunion (atrophic and hypertrophic), segmental defects and fractures at risk of impaired healing were identified. Their accuracy in reflecting the clinical scenario ranged greatly and the reliability of reproducing the scenario ranged from 100% to 40%.

It is vital to know the limitations and success of each model when considering its application.

There are many causes of paraspinal muscle weakness which give rise to the dropped-head syndrome. In the upper cervical spine the central portion of the spinal cord innervates the cervical paraspinal muscles. Dropped-head syndrome resulting from injury to the central spinal cord at this level has not previously been described. We report two patients who were treated acutely for this condition. Both presented with weakness in the upper limbs and paraspinal cervical musculature after a fracture of C2. Despite improvement in the strength of the upper limbs, the paraspinal muscle weakness persisted in both patients. One ultimately underwent cervicothoracic fusion to treat her dropped-head syndrome.

While the cause of the dropped-head syndrome cannot be definitively ascribed to the injuries to the spinal cord, this pattern is consistent with the known patho-anatomical mechanisms of both injury to the central spinal cord and dropped-head syndrome.

Invasive group A streptococcus (iGAS) is the most common cause of monomicrobial necrotising fasciitis. Necrotising infections of the extremities may present directly to orthopaedic surgeons or by reference from another admitting specialty. Recent epidemiological data from the Health Protection Agency suggest an increasing incidence of iGAS infection in England. Almost 40% of those affected had no predisposing illnesses or risk factors, and the proportion of children presenting with infections has risen. These observations have prompted the Chief Medical Officer for the Central Alerting System in England to write to general practitioners and hospitals, highlighting the need for clinical vigilance, early diagnosis and rapid initiation of treatment in suspected cases.

The purpose of this annotation is to summarise the recent epidemiological trends, describe the presenting features and outline the current investigations and treatment of this rare but life-threatening condition.

A series of 26 children was referred to our specialist unit with a ‘pink pulseless hand’ following a supracondylar fracture of the distal humerus after a mean period of three months (4 days to 12 months) except for one referred after almost three years. They were followed up for a mean of 15.5 years (4 to 26). The neurovascular injuries and resulting impairment in function and salvage procedures were recorded. The mean age at presentation was 8.6 years (2 to 12). There were eight girls and 18 boys.

Only four of the 26 patients had undergone immediate surgical exploration before referral and three of these four had a satisfactory outcome. In one child the brachial artery had been explored unsuccessfully at 48 hours. As a result 23 of the 26 children presented with established ischaemic contracture of the forearm and hand. Two responded to conservative stretching. In the remaining 21 the antecubital fossa was explored. The aim of surgery was to try to improve the function of the hand and forearm, to assess nerve, vessel and muscle damage, to relieve entrapment and to minimise future disturbance of growth.

Based on our results we recommend urgent exploration of the vessels and nerves in a child with a ‘pink pulseless hand’, not relieved by reduction of a supracondylar fracture of the distal humerus and presenting with persistent and increasing pain suggestive of a deepening nerve lesion and critical ischaemia.

We assessed the functional outcome following fracture of the tibial plateau in 63 consecutive patients. Fifty-one patients were treated by internal fixation, five by combined internal and external fixation and seven non-operatively. Measurements of joint movement and muscle function were made using a muscle dynamometer at three, six and 12 months following injury. Thirteen patients (21%) had a residual flexion contracture at one year. Only nine (14%) patients achieved normal quadriceps muscle strength at 12 months, while 19 (30%) achieved normal hamstring muscle strength. Recovery was significantly slower in patients older than 40 years of age. We conclude that there is significant impairment of movement and muscle function after fracture of the tibial plateau and that the majority of patients have not fully recovered one year after injury.