Significant Loss Of Strength Research Articles

The Effect of Immobilization on the Native and Repaired Tendon-to-Bone Interface

Little is known of the cellular events that occur in native or repaired tendons as a result of immobilization after injury. To examine this issue, we compared (1) native tendons without immobilization, (2) native tendons with immobilization, and (3) surgically repaired tendons with immobilization. Eighty-one rats underwent either patellar tendon repair followed by immobilization or immobilization of the native tendon without repair. A custom external fixation device was used for immobilization. The tendon-bone insertion site was evaluated after two and four weeks of immobilization with use of histologic, radiographic, and biomechanical analyses. Immobilization of the native tendon led to a significant decrease in the load to failure (p < 0.01) and stiffness (p < 0.05) compared with the native tendon at both two and four weeks. The repaired/immobilized group had a significantly lower load to failure at two weeks compared with the native/immobilized group (p < 0.05); however, by four weeks, the repaired group was significantly stronger (p < 0.01). Micro-computerized tomography demonstrated no significant differences in bone microstructure at two weeks but demonstrated increased bone mineral density and bone volume fraction in the repaired/immobilized group at four weeks. There was significantly more MMP-13 (matrix metalloproteinase-13) staining in the native/immobilized specimens compared with the native specimens at both time points (p < 0.01). Immobilization had a significant detrimental effect on the bone-tendon complex. At two weeks there was a significant decrease in the mechanical properties of the native tendon, but the immobilized, native tendon remained significantly stronger than the repaired and immobilized tendon. However, four weeks of immobilization led to a significant loss of strength of the bone-tendon complex in the native tendon, such that it was significantly weaker than the repaired and immobilized tendon. Surgeons who manage patients with immobilization should be aware of the changes at the bone-tendon complex.

Loss of tensile strength in cellulose tissue on the surface of spruce (Picea abies) caused by natural photodegradation and delignification

Photodegradation of wood leads to discolouration and delignification, inducing damage to the cellular structure. This study is an investigation of the damage and loss of tensile strength of the cellulose fibres in spruce (Picea abies). Microtensile tests in the longitudinal direction on 250-μm-thick microtomed samples were performed on undegraded and degraded spruce specimens. The tested length of the samples for the first series was 10 mm (t-span) to evaluate the entire wood composite degradation process and the interaction between cellulose and lignin. For the second series of samples, the tested length was 0 mm (z-span) to evaluate the fibre strength only. The samples were exposed outdoors on a 45° rack facing south for zero, 12, 16, and 70 weeks. The depth of degradation was studied by testing three 250-μm-thick layers, starting from the surface. With this approach, the real degradation behaviour can be evaluated because the cutting is performed after the exposure, in contrast to classical studies in which the microcuts are exposed directly. The touchless measurement of roughness did support the evaluation of the surface and helps to explain the degradation and erosion of the material.The results revealed a significant loss of tensile strength for the t- and z-spans of the degraded surface (0–250 μm) after 16 weeks of exposure and highlighted the degradation of the cellulose fibres. With the applied method, no significant loss of strength below 250 μm could be measured. However, quantitative analyses via scanning electron microscopy (SEM) showed typical degradation patterns, such as pit destruction and cracking between the cells below 250 μm.For the degraded and nondegraded samples, the tensile strength of the z-span was always twice that for the t-span. In addition, the time-dependent loss of strength always demonstrated the same tendency for both testing methods. This observation indicates a similar degree of degradation of lignin and cellulose in terms of strength loss.

Ageing of thermoplastic umbilical hose materials used in a marine environment I – Polyethylene

This study of the behaviour of high-density polyethylene umbilical hoses subjected to constant and cyclic variation of pressure and temperatures attempts to simulate the temperatures and stresses experienced in offshore operations. The hoses are used to carry fluids to the top of the wellhead and provide protection for the electrical and optical controls systems. Measurements are reported for exposures at 40℃, 70℃ and 100℃ in water, methanol and xylene, using an applied pressure of 200 bar. The changes in the physical properties of the hose were monitored by measurement of the tensile properties, dynamic mechanical thermal analysis, differential scanning calorimetry and gravimetric uptake of the fluids. Significant changes occur immediately on application of pressure and reflect changes in crystallinity. The rates and extent of the modifications depend primarily on the ageing temperature but are also influenced by the fluid. Water has little effect on the rate at which ageing occurs, whereas xylene, which is a potential solvent for high-density polyethylene, exhibits characteristics of plasticization. Methanol behaves as a weak solvent and shows characteristics intermediate between xylene and water. Burst tests carried out on the aged material show that significant loss in strength is only observed with the highest temperatures and most aggressive solvent systems. The study indicates that engineers should use pressure-aged rather than initial materials data when designing umbilical hose systems.

The pronator quadratus muscle after plating of distal radius fractures: is the muscle still working?

The purpose of this study is to define the function of the pronator quadratus muscle after plating of a distal radius fracture using anterior (volar) approach. Fourteen cases with volar plating after for a distal radius fracture were included in the study. Sixteen healthy volunteers were selected to determine the effect of dominant arm on pronation torque of the forearm for the control group. Biodex System 4 PRO (Biodex Medical Systems Inc., New York) torque meter was used for pronation torque measurement. In healthy volunteer group, there was no statistically significant difference in mean pronation torque values between the dominant arm and nondominant arms. The mean loss of pronator strength was 18.5% and the mean loss of pronator durability was 12.9% indicating a pronator insufficiency in the cases operated by a volar approach compared to uninjured forearm. Two patients among the operated group, who had further strengthening exercises beyond their own rehabilitation regimes, had improved pronator torque compared to uninjured forearm. In conclusion, the results of this study indicate that following volar plating of distal radius fractures, there is a significant loss in pronator strength of the forearm. As the two of the patients had improved pronator strength of their operated forearm, further rehabilitation regimes should be considered to prevent pronator weakness following volar plating for distal radius fractures.

Web Buckling in Pultruded Fiber-Reinforced Polymer Deep Beams Subjected to Concentrated Loads

Five 609.5-mm deep fiber-reinforced polymer (FRP) beams with a span-to-depth ratio of 4∶1 were tested in three-point bending with the beam ends constrained to prevent global failure. A concentrated load was applied at midspan either directly to the top flange or through a 101.6 mm wide by 12.7-mm thick FRP bearing plate resting on the top flange. VIC-3D Digital Image Correlation Measurement Software from Correlated Solutions captured out-of-plane displacement of the webs, and Southwell plots were generated to determine buckling loads. Each specimen experienced a stability failure of the web before undergoing material failure in the upper web-flange junction. On average, web buckling occurred at 90% of the ultimate load. The introduction of a bearing plate did not significantly affect the buckling load or ultimate capacity of the specimens. One specimen was tested into the postbuckling range, unloaded, and reloaded to material failure and experienced no loss of strength or stiffness. Another specimen with significant damage to the unloaded web-flange junction was tested and compared with a virgin sample. The damaged sample experienced no significant loss of strength or stiffness. Comparisons of experimental data with three theoretical equations for web-buckling capacity of FRP beams are provided.

Influence of exfoliation corrosion on tensile properties of a high strength Al-Zn-Mg-Cu alloy

The influence of exfoliation corrosion on the tensile properties of a high strength Al-Zn-Mg-Cu alloy was investigated by ambient temperature tensile testing, optical microscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). After exfoliation corrosion immersion, blisters and corrosion pits can be seen on the sheet surface, which lead to loss of materials and notches. A number of intergranular cracks are observed to initiate at the bottom of the corrosion-induced notches and propagate rapidly into the bulk materials during tensile. Consequently, exfoliation corrosion results in significant loss of strength and brittle fracture. EBSD results show that the crack propagation path is primarily along the grain boundaries with misorientation of ∼45°, and coincidence site lattice (CSL) boundaries are slightly more resistant to crack.

Bending Performance of Box-Based Cross-Laminated Timber Systems

AbstractCross-laminated timber (CLT) is a growing phenomenon and a recent building solution alternative in timber construction in North America by using massive or solid wood plates as roof, floor, and wall elements. In this paper a variation of the conventional CLT is considered by studying the performance of box-based CLT systems, which refer to box beams with multiple voids. In some loading situations, such as out-of-plane bending, these systems, which can reduce structural weight without significant loss of strength or stiffness, may be structurally efficient and cost competitive. Comprehensive three-dimensional finite-element models, which can be used to analyze the mechanical behavior of such box structures, were developed. Four prototype layups, each having five replicates, were designed, manufactured in-house, and tested under symmetric four-point bending (also known as third-point loadings). The numerical analysis agreed well with experimental data in terms of vertical deflection and flexural rig...

The effect of cement dosage on mechanical properties of concrete exposed to high temperatures

Although concrete is a non-combustible material, it is found that when exposed to high temperatures, such as fire, the physical, chemical and mechanical properties of concrete can drastically change. Thus, it becomes important to assess the relative properties of concrete under high temperatures in order to evaluate and predict the post-fire response of reinforced concrete (RC) buildings and structures. This paper assesses the effects of elevated temperatures and cement dosages on the mechanical properties of concrete. Two concrete mix designs were considered in this research in an attempt to study the effects of cement dosage (250 and 350kg/m3) on the post-fire response of concrete. Once cast, the test samples were first exposed to elevated temperatures ranging from 100 to 800°C, and then allowed to cool down slowly to ambient room temperature of 20°C before being tested to failure. Several tests were then carried out to determine the mechanical properties of the cooled concrete specimens. The test results indicated that at temperature above 400°C, concrete undergoes significant strength loss when compared to the strength of non-heated concrete. In addition this strength reduction was found to be unaffected by the cement dosages. The experimental results were also compared with current European standard (BS EN 1992-1-2:2004 standard) strength equations and American Concrete Institute standard (ACI 216.1).

Cinco Años de Radiomarcaje de Osos Hormigueros (Myrmecophaga tridactyla): Mejoras Implementadas y Lecciones Aprendidas

Several authors have proposed using harnesses to attach radio transmitters to giant anteaters. We assessed harness endurance and applicability on giant anteaters of different ages, tested improvements on its design, and evaluated potential negative impacts on reproduction. We also assessed the performance of an internal transmitter in a female anteater. We radiotagged 29 animals (26 reintroduced and three in-situ-born cubs) with 37 VHF harness-mounted transmitters, accumulating 370 months of radiotracking giant anteaters in Iberá Natural Reserve, Corrientes, Argentina. Each animal was periodically recaptured finding harness-related wounds in four cases for a total of 82 recaptures. All these wounds were properly treated and healed, and there were no cases of deaths related to harnesses. We designed and field-tested modifications on the transmitter canister shape that reduced resistance to vegetation, and also included an expandable section added to the strap around the thorax that prevented animals from removing their harnesses, while avoiding injuries related to changes in the anteater's weight. The internal implant resulted in a significant loss in signal strength. As result of our experience, we recommend the use of harnesses as the best way to attach radio-transmitters to giant anteaters because they offer the best quality of signal while having no apparent effect on reproduction. However, we highly recommend periodical recaptures of radio-harness tagged animals to avoid potentially fatal wounds coming from ill-adjusted harnesses in animals that are experiencing sharp changes in weight.

Arthroscopic Excision of Os Acromiale: Effects on Deltoid Function and Strength

Arthroscopic excision of os acromiale is a feasible alternative to open excision or fusion. This article describes the authors' experience with 28 patients (31 shoulders) who underwent arthroscopic excision of os acromiale and its effect on shoulder pain and function, with specific emphasis on deltoid strength measurement. Thirty-one os acromiale (all persistent unfused pre- and meso-acromions) in 28 patients were excised arthroscopically. Sixteen patients underwent concomitant rotator cuff repair (9 arthroscopic and 7 mini-open). At an average follow-up of 41 months, the patients were assessed using the American Shoulder and Elbow Surgeons (ASES) score, and deltoid function and strength were measured. Pain was completely alleviated postoperatively in 20 (65%) shoulders, and 9 (29%) shoulders had less pain postoperatively. Pain worsened postoperatively in 2 patients, both of whom had features of glenohumeral arthritis at arthroscopy. Average postoperative ASES score (80.33) was significantly improved compared with the average preoperative score (33.71). No significant loss of deltoid strength occurred compared with the contralateral side. No objective or subjective loss of normal deltoid appearance occurred. Rotator cuff repair did not compromise deltoid strength or significantly reduce ASES score irrespective of repair technique (arthroscopic vs mini-open). With careful attention to surgical technique maintaining an intact periosteal sleeve to preserve the integrity of the deltoid attachment, arthroscopic excision is an effective management tool for mobile os acromiale in a painful shoulder requiring surgical intervention.

Biomechanical effects of steroid injections used to treat pyogenic flexor tenosynovitis

BackgroundA recent study from our laboratory has demonstrated improved range of motion in the toes of broiler chickens afflicted with pyogenic flexor tenosynovitis when treated with local antibiotic and corticosteroid injections, without surgical drainage. However, the use of corticosteroids as an adjunct treatment raised peer concern, as steroids are thought to have deleterious effects on tendon strength. The purpose of this study was to compare the tensile strength of the aforementioned steroid treated tendons, to a group of tendons administered with the current standard treatment: systemic antibiotics, surgical drainage and no corticosteroids.MethodsTwenty-three tendons’ structural and material properties were investigated (fifteen receiving the standard treatment, eight receiving the steroid treatment). The measurements from each group were interpreted via Student’s unpaired t-test and a post-hoc power analysis.ResultsThe steroid treated tendons did demonstrate a trend toward decreased mechanical properties when compared with the standard treatment group, but the results were not statistically significant.ConclusionsTreatment of septic tenosynovitis with local corticosteroid and local antibiotic injections resulted in better digital motion, without a significant loss of tendon strength, over a twenty-eight day recovery period.

Inelastic deformation and failure of partially strengthened profiled blast walls

An integral part of a typical offshore module is the surrounding profiled blast walls that separate the potentially hazardous regions of the topside. Many of the blast walls in operation were designed to resist lower loads than those envisaged today [1] rendering them currently non-functional, thus it is desirable to upgrade their blast resistance in a cost-effective and non-intrusive manner. One proposal is to retrofit the existing blast walls partially with centrally located composite patches. This study presents the development of a rapid assessment tool which provides understanding of the effect of a composite patch on the blast resistance of profiled blast walls. The tool is based and is an improvement upon a previous analytical formulation for unstrengthened walls with realistic connection systems [2]. Numerical simulations of a proposed retrofitted wall are performed to gain insight into the failure progression of the wall. Damage in the composite patch is modelled using the Hashin damage model, and the numerical simulations showed that fibre fracture did not occur and that the small amounts of matrix failure occurring at the composite patch edges did not result in significant loss of in-plane stiffness and strength. Based on these observations the rapid assessment tool, analytically formulated to incorporate the effect of the composite patch which strengthens the wall and moves the plastic hinge locations away from the wall centre to the composite-steel edge, is deemed a suitable tool. The assessment tool and the numerical simulations are partially validated by the experimental results presented in [1] for unstrengthened blast walls. The tool runs quickly and provides reasonable predictions for the deformation response of the walls, and enables the user to quickly assess the effect of adding a composite patch. It allows for multiple deformation modes in the panels and the development of plastic hinges at the composite-steel edges and the wall connections, providing a significant advantage over conventional single-degree-of-freedom models. The numerical simulations and the rapid assessment tool give reasonable agreement for different loading regimes, given the anticipated use of the analytical approach.

Análise comparativa da força muscular entre pacientes tenotomizados artroscopicamente da cabeça longa do bíceps com relação à deformidade estética

OBJETIVO: Determinar se há discrepância na força de flexão do cotovelo entre pacientes com (CD) e sem a deformidade clínica (SD) evidente resultante da tenotomia artroscópica da cabeça longa do bíceps (TACLB). MÉTODOS: Foi analisado um grupo de 120 pacientes submetidos à TACLB, que após os critérios de exclusão, resultaram em 89. Foi avaliada, com uma mediana de 18 meses de pós-operatório, a força de flexão do cotovelo em Newton (N) por meio de um dinamômetro digital. Foram realizadas três medidas consecutivas e considerada a média comparando o lado dominante com o não dominante. Foram estudados: sexo, idade, média da força de flexão do cotovelo no MS operado e do MS contralateral de pacientes com e sem a deformidade clínica aparente. RESULTADOS: Foi comparada a força de flexão do cotovelo no grupo CD e verificada uma mediana 17,78N para o membro superior dominante e uma mediana 20,87N para o membro superior não dominante. A diferença foi de 2,51N. No grupo SD a diferença foi de 2,14N. Foi verificada uma mediana de força muscular dos MS operados de 17,26N, enquanto os MS não operados tiveram uma mediana de 20,06N sugerindo perda de força muscular significativa (p = 0,005). A diferença entre a perda de força muscular entre os pacientes com e sem deformidade evidente não foi considerada estatisticamente significativa (p = 0,977). CONCLUSÃO: Os pacientes submetidos à TACLB com ou sem deformidade clínica aparente de sua migração distal apresentam força muscular de flexão do cotovelo semelhantes.

Assessment of the Benefit of Powered Exercises for Muscular Endurance and Functional Capacity in Elderly Participants

Aging is accompanied by a significant loss of strength which further contributes to loss of functional ability and a propensity for injury. The purpose of this study was to assess the effectiveness of power assisted exercises on muscle endurance and functional capacity of elderly participants following 12 weeks of supervised training. Elderly subjects (N = 53) were randomly assigned to either the experimental or the control group. The experimental group trained for 12 weeks using powered exercise machines incorporating only concentric contractions while attempting to accelerate the preset, moving levers. Training involved 6 separate machines and using both upper- and lower-body musculature. Pre- and posttests consisted of Timed Chair Stand, Up and Go Test, arm curl, bench press, leg extension, triceps extension, and the Berg Balance Scale Assessment. Analysis yielded significant improvements (P < .05) by the experimental group over the control group in all measures of muscle endurance, balance, and functional capacity. An improvement in balance paralleled muscle endurance improvements. Powered exercise equipment when used actively, will generate both upper- and lower-body muscle endurance in elderly participants in a safe exercise environment and such improvement also generated improvement in balance.

COMPARATIVE ANALYSIS ON MUSCLE STRENGTH AMONG PATIENTS WHO UNDERWENT ARTHROSCOPIC TENOTOMY OF THE LONG HEAD OF THE BICEPS IN RELATION TO ESTHETIC DEFORMITY

Objective: To determine whether there was any discrepancy in elbow flexion strength among patients with and without evident clinical deformity resulting from arthroscopic tenotomy on the long head of the biceps. Method: A group of 120 patients who underwent this procedure were evaluated. After applying the exclusion criteria, 89 patients remained in the analysis. Eighteen months after the operation (median), the elbow flexion strength was measured in newtons using a digital dynamometer. Three consecutive measurements were made and the average was used. The dominant and non-dominant sides were compared. Sex, age and mean elbow flexion strength in the operated and contralateral arms of patients with and without apparent clinical deformity were evaluated. Results: The median elbow flexion strength among the patients with evident clinical deformity was 17.78 N for the dominant arm and 20.87 N for the non-dominant arm. The difference was 2.51 N. In the group without evident clinical deformity, the difference was 2.14 N. The median muscle strength in the operated arm was 17.26 N, while the median was 20.06 N in the non-operated arm, thus suggesting that there was a significant loss of muscle strength (p = 0.005). The difference in muscle strength loss between the patients with and without evident deformity was not considered statistically significant (p = 0.977). Conclusion: The patients who underwent arthroscopic tenotomy on the long head of the biceps with or without apparent clinical deformity from distal migration presented similar elbow flexion muscle strength.

Reconstruction of the Fires and Thermal Environment in World Trade Center Buildings 1, 2, and 7

The National Institute of Standards and Technology (NIST) conducted an extensive investigation of the collapse of the three tall World Trade Center (WTC) buildings. A central part of this investigation was the reconstruction and understanding of the initiation and spread of the fires. This paper describes the reconstruction of the fires, the thermal environment they created within the buildings, and the raising of the temperatures of the structural components. NIST analyzed thousands of documents, interviews, photographs, and videos to obtain information on the layout of the floors and the progress of the fires. Experiments provided information on the factors likely to have determined the fire growth. Simulations using the Fire Dynamics Simulator gave good agreement with the fire spread as observed at the windows. Imposition of the probable thermal environment on the structural steel produced maps of the probable temperature profile of the steel as the fires progressed. For WTC 1 and WTC 2, even in the vicinity of the fires, it was unlikely that the columns and floor trusses with intact insulation heated to temperatures where significant loss of strength occurred. This was in part due to the short time between aircraft impact and building collapse. There were regions of the towers in which the loss of structural strength of floors and columns, whose insulation had been damaged by aircraft impact, was likely. For WTC 7, even though the insulation was intact, the long periods of heating resulted in floor components whose temperatures exceeded 600°C, but columns did not exceed 300°C.

Evaluation of biomechanical and histological properties of corrosive chemical burns

This study was aimed to prepare a standard experimental chemical burns and evaluate biomechanical and histological properties. As a model corrosive acid burns, sulfuric acid burns were made on the peritoneal part of the rabbit ear with diameter 8 mm by varing sulfuric acid concentrations (1, 2, 18.8 M) and inflicted time (20, 40, 60 and 120 s). The progress of the chemical injury was evaluated for 3 weeks by macroscopic and microscopic observation. Degree of regeneration of damaged epidermis and dermis and presence of infected cells and arrangements of collagen were investigated. Histology of 18.8 M sulfuric acid for 20 s burns showed epidermal necrosis, diffuse vascular infiltrate and collagen degeneration at the level of the papillary dermis, which is a characteristic of a deep dermal burn. The stress–strain curves of normal skin, 18.8 M sulfuric acid treated wound, 6 mm surgical biopsy punch wound and at 21 days post wound were evaluated. As tensile strength measures the ability of matrix to withstand rupture, as the damage from corrosive acid chemical involved wider and deep skin area with permanent damage, the healing could not be processed complete and showed less than 16 % of tensile strength (0.05 ± 0.01 N/mm2) as compared with those of normal skin (0.31 ± 0.08 N/mm2). The sulfuric acid inflicted wound showed flatter, reflecting the small magnitude of their moduli of elasticity. The elasticity constant for sulfuric acid treated skin (1.46 ± 0.17 N/mm) is only 25 % of those of normal skin (5.87 ± 2.14 N/mm). Surgical punch wound showed higher tensile strength (0.10 ± 0.02 N/mm2) and elasticity constant (4.19 ± 0.47 N/mm) than those of corrosive chemical acid burns. In conclusion, the proposed sulfuric acid burn condition (18.8 M, 20 s) could be employed as a useful corrosive chemical wound model. The degree of damage induced by corrosive acid chemicals is more significant than surgical full thickness wound and was dependent on the concentration and treatment time. By controlling the burn condition, the extent of damage could be designed. Biomechanical and histological study demonstrated that the corrosive acid burns induced full thickness permanent dermal injury and significant losses in tensile strength and elasticity modulus.

Changes in engineering properties of natural stone

It has long been known that some stone types show significant loss in strength, both in compression and bending during the service life of a building. These differences can include changes as a result of long-term changes in physical structure, for example as a result of thermal and moisture cycles, but there can also be shorter term changes between the wet and dry states. The European Standards that are now in place in the UK and the rest of the CEN countries require stones to be tested under ambient conditions and, if required to declare these values as part of the CE marking process. This has led to some concerns that the data available for structural calculations may not reflect the actual performance during use, and as the demands for more slender stone units increase so the margins for error become smaller. The present paper begins by examining a number of reported examples of changes in properties with time as a result of changes in structure in some marbles as well as changes in appearance and strength in limestone and sandstone as a result of salt damage and freeze-thaw action.

Modified Extensor Carpi Radialis Brevis Adductorplasty for Ulnar Nerve Palsy

Residual paralysis or irreparable injury to the ulnar nerve results in considerable impairment of hand function and posture that directly affect daily living. Usually, claw hand deformity and loss of key pinch become problematic, but tendon transfer can be used to restore the lost functions. Adductorplasty using a wrist extensor tendon can restore thumb adduction strength without a significant loss of wrist extension strength, but the short length of the wrist extensor necessitates a free tendon graft to reach the thumb. Here, the authors present a modified extensor carpi radialis brevis adductorplasty technique that does not need a tendon graft by elongating the tendinous portion.

Erythropoietin enhances the regeneration of traumatized tissue after combined muscle-nerve injury

Erythropoietin (EPO) is a pleiotropic cytokine with neuroprotective, anti-inflammatory, and muscle regenerative properties. The purpose of our study was to analyze the regenerative capacity of systemically applied EPO in a combined muscle-nerve injury model. We performed a crush injury to the left soleus muscle in 84 male Wistar rats. Using an instrumented clamp, the muscle was crushed over its complete length. Simultaneously, the ipsilateral sciatic nerve was sham manipulated or crushed. Upon induction of the trauma, animals received either EPO (E) (single application of 5,000 IU/kg body weight intraperitonial) or vehicle solution (K). After in vivo assessment of mechanical pain according to Frey, thermal hyperalgesia, latency of nerve conduction velocity, and strength of the soleus muscle were analyzed at days 1, 7, and 42 postinjury (n = 7 per group). Cell proliferation and apoptosis were assessed by means of histology and immunohistochemistry. Combined muscle-nerve injury showed a significant loss of muscle strength, which incompletely recovered within 42 days. Rats treated with EPO showed an increased muscle strength after 7 days and 42 days compared with the control group. Pain behavior was highest in the muscle-nerve injured animals at day 7. EPO decreased the pain and increased nerve conduction velocity. Nerve injury diminished proliferation of muscle cells, whereas simultaneous therapy with EPO resulted in a boost of bromdesoxyuridine-positive cells. EPO promoted muscle restoration and enhanced nerve recovery after combined muscle-nerve injury. Thus, EPO might represent an attractive therapeutic option to optimize the posttraumatic course after injury.