Tendon injuries of the hand

Tendon injuries are the second most common injuries of the hand and therefore an important topic in trauma and orthopedic patients. Most injuries are open injuries to the flexor or extensor tendons, but less frequent injuries, e.g., damage to the functional system tendon sheath and pulley or dull avulsions, also need to be considered. After clinical examination, ultrasound and magnetic resonance imaging have proved to be important diagnostic tools. Tendon injuries mostly require surgical repair, dull avulsions of the distal phalanges extensor tendon can receive conservative therapy. Injuries of the flexor tendon sheath or single pulley injuries are treated conservatively and multiple pulley injuries receive surgical repair. In the postoperative course of flexor tendon injuries, the principle of early passive movement is important to trigger an “intrinsic” tendon healing to guarantee a good outcome. Many substances were evaluated to see if they improved tendon healing; however, little evidence was found. Nevertheless, hyaluronic acid may improve intrinsic tendon healing.

Management of failed metal-on-metal total hip arthroplasty

The theoretical advantages of metal-on-metal (MOM) bearing couples in total hip arthroplasty (THA) have been recently balanced by concerns regarding adverse local and systemic effects. Higher than anticipated early revision rates have been reported by several joint registries. Failed MOM hips present with a spectrum of symptoms and findings and traditional methods of failure must be considered in addition to the failure modes that appear to be unique to the MOM bearing couple. Metal hypersensitivity and soft tissue immune reactions remain incompletely understood and require careful ongoing study. The tools available to evaluate MOM THAs and the indications for revision surgery remain to be defined. Outcomes following revision of MOM hips appear to depend on appropriate evaluation, early identification, and appropriate surgical management.

Scurvy: An unusual presentation of cerebral palsy

Scurvy is caused by prolonged severe dietary deficiency of ascorbic acid, in which the breakdown of intercellular cement substances leads to capillary hemorrhages and defective growth of fibroblasts, osteoblasts and odontoblasts, resulting in impaired synthesis of collagen, osteoid and dentine. It is characterized by hemorrhagic gingivitis, subperiosteal hemorrhages, perifollicular hemorrhages, and frequently petechial hemorrhages (especially on the feet). People with abnormal dietary habits, mental illness or physical disability are prone to develop this disease. Epiphyseal separation is known to occur in scurvy but is rarely seen now. Epiphyseal separation from the metaphysis is always through the zone of calcified cartilage, known as “scorbutic lattice”, which in the radiographs is represented as “the white line of Frenkel”. We report a case of multiple epiphyseal separations in a cerebral palsy child because of vitamin C deficiency. The child was treated with splintage of extremity and nutritional supplementation. All physeal separation healed completely without any deformity.

Total hip arthroplasty in developmental dysplasia of the hip: Review of anatomy, techniques and outcomes

Total hip arthroplasty (THA) in developmental dysplasia of the hip (DDH) presents many challenges to the reconstructive surgeon. The complex femoral and acetabular anatomy makes standard reconstruction technically challenging. Acetabular coverage can be improved by medialization of the component or augmentation of the deficient areas with bone graft. Femoral shortening osteotomies are considered in cases of severe dysplasia and frankly dislocated hips. Each patient’s unique anatomy dictates what options of reconstruction are available. The functional outcomes of THA in DDH are generally excellent, though higher rates of mechanical failure have been reported in this group. This article reviews the anatomy, classification, technical considerations, and outcomes of THA in patients with DDH.

Osteonecrosis of the femoral head: An update in year 2012

Osteonecrosis is a phenomenon involving disruption to the vascular supply to the femoral head, resulting in articular surface collapse and eventual osteoarthritis. Although alcoholism, steroid use, and hip trauma remain the most common causes, several other etiologies for osteonecrosis have been identified. Basic science research utilizing animal models and stem cell applications continue to further elucidate the pathophysiology of osteonecrosis and promise novel treatment options in the future. Clinical studies evaluating modern joint-sparing procedures have demonstrated significant improvements in outcomes, but hip arthroplasty is still the most common procedure performed in these affected younger adults. Further advances in joint-preserving procedures are required and will be widely studied in the coming decade.

Applications of finite element simulation in orthopedic and trauma surgery

Research in different areas of orthopedic and trauma surgery requires a methodology that allows both a more economic approach and the ability to reproduce different situations in an easy way. Simulation models have been introduced recently in bioengineering and could become an essential tool in the study of any physiological unity, regardless of its complexity. The main problem in modeling with finite elements simulation is to achieve an accurate reproduction of the anatomy and a perfect correlation of the different structures, in any region of the human body. Authors have developed a mixed technique, joining the use of a three-dimensional laser scanner Roland Picza captured together with computed tomography (CT) and 3D CT images, to achieve a perfect reproduction of the anatomy. Finite element (FE) simulation lets us know the biomechanical changes that take place after hip prostheses or osteosynthesis implantation and biological responses of bone to biomechanical changes. The simulation models are able to predict changes in bone stress distribution around the implant, so allowing preventing future pathologies. The development of a FE model of lumbar spine is another interesting application of the simulation. The model allows research on the lumbar spine, not only in physiological conditions but also simulating different load conditions, to assess the impact on biomechanics. Different degrees of disc degeneration can also be simulated to determine the impact on adjacent anatomical elements. Finally, FE models may be useful to test different fixation systems, i.e., pedicular screws, interbody devices or rigid fixations compared with the dynamic ones. We have also developed models of lumbar spine and hip joint to predict the occurrence of osteoporotic fractures, based on densitometric determinations and specific biomechanical models, including approaches from damage and fracture mechanics. FE simulations also allow us to predict the behavior of orthopedic splints applied to the correction of deformities, providing the recovering force-displacement and angle-moment curves that characterize the mechanical behavior of the splint in the overall range of movement.

Evaluation of utility in shoulder pathology: Correlating the American Shoulder and Elbow Surgeons and Constant scores to the EuroQoL

AIM: To study whether health utility scores can be derived from shoulder-specific scores.

METHODS: Authors investigated two questions: (1) do the American Shoulder and Elbow Surgeons (ASES) score and the Constant score correlate with the EuroQoL (EQ-5D), a measure of health utility? (2) can the ASES and Constant scores be obtained from a complete study sample without bias? Thirty subjects with various shoulder diagnoses completed ASES, Constant, and EQ-5D instruments. Pearson correlations were calculated to assess the associations between EQ-5D score and ASES and Constant scores.

RESULTS: The correlation between EQ-5D score and ASES score was 0.60 (P < 0.001); it was 0.54 for EQ-5D and Constant scores (P < 0.003). A multiple regression model containing ASES score, Constant score, age, and gender failed to adequately predict EQ-5D. Moreover, 25% of patients meeting the inclusion criteria did not complete the ASES questionnaire because they did not feel that specific questions, such as “do usual sport - list” and “throw ball overhand,” applied to them.

CONCLUSION: Authors’ results do not support the use of the ASES and Constant scores in predicting EuroQol health utility values. However, the Constant score was more suitable for this patient population because all patients were able to complete it.

Measurement of forces generated during distraction of growing-rods in early onset scoliosis

AIM: To measure the forces applied during distraction of growing-rods in early onset scoliosis (EOS), aimed at developing a motorized elongation device.

METHODS: A consecutive series of measurements were carried out to analyze the forces applied by the surgeon during distraction of single growing-rods in 10 patients affected by EOS (mean age 8.3 years; range 6 to 10 years) undergoing the first distraction 6 months following implantation of the rods. For each measurement, output from the transducer of a dedicated pair of distraction calipers was recorded at zero load status and at every 1 mm of distraction, up to a maximum of 12 mm for each of the two connected rods.

RESULTS: Twenty measurements were obtained showing a linear increase of the load with increasing distraction, with a mean peak force of 485 N at 12 mm distraction and a single reading over 500 N. We did not observe bone fractures or ligament disruptions during or after rod elongations. There was one case of superficial wound infection in the cohort.

CONCLUSION: The safe peak force carrying capacity of a motorized device for distraction of growing-rods is 500N.

Innervation of cervical ventral facet joint capsule: Histological evidence

AIM: To assess the presence of nerves in ventral facet joint capsules as facet capsules are generally implicated in neck pain.

METHODS: Twenty-four ventral cervical facet joint capsules were harvested from 3 unembalmed cadavers. Paraffin sections from these capsules were processed to identify neurofilament and substance P immunoreactive fibers. Nerve fiber presence was also verified by a silver impregnation method.

RESULTS: Neurofilament reactive fibers were observed in sections from 9 capsules. They were observed in areas with collagen fibers and areas with irregular connective tissue. Substance P reactive nerve fibers were found in sections from 7 capsules in similar areas. Silver impregnation also revealed the presence of nerve fibers. The nerve fibers were also found as bundles in the lateral margins of the capsule. A Pacinian corpuscle-like ending was also observed in one specimen.

CONCLUSION: Nerve fibers revealed by neurofilament immunoreactivity and silver staining support innervation of the ventral aspect of the facet joint capsule. The presence of substance P reactive fibers supports the potential role of these elements in mediating pain. The presence of a Pacinian-like ending implicates a potential role in joint movement.

Factors affecting response rates to mailed preoperative surveys among arthroplasty patients

AIM: To identify factors that affect patient response rates to preoperative functional surveys in hip and knee arthroplasty patients.

METHODS: From May 2008 to March 2009, 247 patients were scheduled more than 4 wk in advance for hip or knee arthroplasty by one of two participating surgeons at our center. A personalized questionnaire comprised of the Short Form 12 (SF-12) and Western Ontario and McMaster Universities (WOMAC) Index was mailed to patients at random time points ranging from 7 to 101 d prior to surgery. Nine independent factors were documented prospectively, including age, gender, ethnicity, marital status, type of surgery, surgeon, days prior to surgery (DPS) of survey mailing, WOMAC score and SF-12 score. The date of the completed survey receipt was also documented. For non-responders, the surveys were completed with the research team at the hospital upon admission. Multivariate regression and χ² analysis were performed with Statistical Analysis Software software.

RESULTS: DPS was the only factor that affected patient response. Mailing surveys 26 d to 31 d prior to surgery dates led to a peak response rate of 80% that was significantly higher (P < 0.023) than response rates for patients who were mailed their surveys ≤ 16 d (62.5%), 17 d to 25 d (70%) or ≥ 32 d prior to surgery (55%). No other factors, including preoperative WOMAC and SF-12 scores, significantly influenced response behavior.

CONCLUSION: The DPS was independently the most significant predictor of response rates for pre-operative functional data among patients scheduled for hip and knee arthroplasty.

Analyses of possible risk factors for subacromial impingement syndrome

AIM: To evaluate the association between various risk factors, including sleeping position, and impingement syndrome. Impingement syndrome is the most common cause of shoulder problems. The pathogenesis of this problem is still debated these days.

METHODS: This was a case control study conducted at the outpatient clinic of Songklanakarind hospital. Data regarding history, physical examination and radiographic evaluations using supraspinatous outlet views were obtained from all patients with clinically suspected impingement syndrome. The diagnoses of impingement syndrome were confirmed by a xylocaine subacromial injection test. All patients were interviewed concerning their usual sleeping position, which was categorized into supine, decubitus, prone and undetermined. Radiographs were evaluated to determine the shape of the acromion, which was divided into 3 types: flat, curved and hook. We used logistic regression analysis to determine the association between risk factors and outcome.

RESULTS: The study group included 111 patients with impingement syndrome and 191 healthy volunteers as a control group. The mean age was about 50 years with a body mass index (BMI) of 24 kg/m² in both groups. The most common shape of the acromion was flat (84.5%), followed by curved (10.7%) and hook (4.8%). We found the 4 independent risk factors affecting impingement syndrome were smoking status, occupation, acromion shape and sleeping position. Patients who currently smoked had a 6.8 times greater risk of impingement syndrome compared to non-smokers (OR 6.8, 95% CI: 1.2-39) and government officers had a 6.3 times increased risk compared to rubber tappers (OR 6.3, 95% CI: 1.3-30.3). Patients with a hook type acromion had 6.2 times the risk of flat type (OR 6.2, 95% CI: 1.1-35) and patients who slept in the decubitus position had 3.7 times the risk of those who slept in the supine position (OR 3.7, 95% CI: 1.2-11.6). No significant associations were found between age, sex, BMI, sports activity and impingement syndrome.

CONCLUSION: Independent risk factors affecting impingement syndrome are current smoker, government officer, a hook-type acromion and the decubitus sleeping position.

Stochastic resonance whole body vibration reduces musculoskeletal pain: A randomized controlled trial

AIM: To examined the effects of stochastic resonance whole-body vibration training on musculoskeletal pain in young healthy individuals.

METHODS: Participants were 43 undergraduate students of a Swiss University. The study was designed as a randomized controlled trial (RCT) with randomized group allocation. The RCT consisted of two groups each given 12 training sessions during four weeks with either 5 Hz- Training frequency (training condition) or 1.5 Hz Training frequency (control condition). Outcome was current musculoskeletal pain assessed in the evening on each day during the four week training period.

RESULTS: Multilevel regression analysis showed musculoskeletal pain was significantly decreased in the training condition whereas there was no change in the control condition (B = -0.023, SE = 0.010, P = 0.021). Decrease in current musculoskeletal pain over four weeks was linear.

CONCLUSION: Stochastic resonance whole-body vibration reduced musculoskeletal pain in young healthy individuals. Stochastic resonance vibration and not any other exercise component within training caused pain reduction.

Classification criteria for spondyloarthropathies

Spondyloarthropathies (SpA) are a group of inflammatory arthritis which consist of ankylosing spondylitis (AS), reactive arthritis, arthritis/spondylitis associated with psoriasis (PsA), and arthritis/spondylitis associated with inflammatory bowel diseases. It is now more important than ever to diagnose and treat SpA early. New therapeutic agents including blockers of tumor necrosis factor have yielded tremendous responses not only in advanced disease but also in the early stages of the disease. Sacroiliitis on conventional radiography is the result of structural changes which may appear late in the disease process. However, magnetic resonance imaging (MRI) can visualize active inflammation at sacroiliac joints and spine in recent onset disease. The modified New York criteria, the European Spondyloarthropathy Study Group criteria and the Amor criteria do not include advanced imaging techniques like MRI which is very sensitive to the early Inflammatory changes. Assessment of SpondyloArthritis international Society has defined MRI methods for the assessment of sacroiliac joints and spine, criteria for inflammatory back pain and developed new criteria for classification of axial and peripheral spondyloarthritis. These new criteria are intended to be used for patients with SpA at the very early stage of their disease. Also, classification of psoriatic arthritis study group developed criteria for the classification of PsA. The widespread use of these criteria in clinical trials will provide evidence for a better definition of early disease and recognize many patients who may further develop classical AS or PsA. These efforts will guide therapeutic trials of potent drugs like biological agents in the early stage of these diseases.

Current concepts in end-to-side neurorrhaphy

In peripheral nerve injury, end-to-side neurorrhaphy involves coaptation of the distal stump of a transected nerve to the trunk of an adjacent donor nerve. It has been proposed as an alternative technique when the proximal stump of an injured nerve is unavailable or the nerve gap is too long to be bridged by a nerve graft. Experimental and clinical data suggests that end-to-side neurorrhaphy can provide satisfactory functional recovery for the recipient nerve, without any deterioration of the donor nerve function. The most accepted mechanism of nerve regeneration following end-to-side neurorrhaphy is collateral sprouting. The source of the regenerating axons traveling in the epineurium of the donor nerve is thought to be the proximal Ranvier’s nodes at the site of end-to-side neurorrhaphy, however, histologic evidence is still lacking. Partial neurotomy of the donor nerve may enhance regeneration of motor neurons through end-to-side neurorrhaphy and reinnervation of motor targets.

Role of polyethylene particles in peri-prosthetic osteolysis: A review

There is convincing evidence that particles produced by the wear of joint prostheses are causal in the peri-prosthetic loss of bone, or osteolysis, which, if it progresses, leads to the phenomenon of aseptic loosening. It is important to fully understand the biology of this bone loss because it threatens prosthesis survival, and loosened implants can result in peri-prosthetic fracture, which is disastrous for the patient and presents a difficult surgical scenario. The focus of this review is the bioactivity of polyethylene (PE) particles, since there is evidence that these are major players in the development and progression of osteolysis around prostheses which use PE as the bearing surface. The review describes the biological consequences of interaction of PE particles with macrophages, osteoclasts and cells of the osteoblast lineage, including osteocytes. It explores the possible cellular mechanisms of action of PE and seeks to use the findings to date to propose potential non-surgical treatments for osteolysis. In particular, a non-surgical approach is likely to be applicable to implants containing newer, highly cross-linked PEs (HXLPEs), for which osteolysis seems to occur with much reduced PE wear compared with conventional PEs. The caveat here is that we know little as yet about the bioactivity of HXLPE particles and addressing this constitutes our next challenge.

Methods to shorten the duration of an external fixator in the management of tibial infections

Massive segmental bone loss due to chronic osteomyelitis represents a considerable challenge to orthopedic surgeons and is a limb threatening condition. The only option available in such a clinical situation is segment transport using the Ilizarov technique of distraction osteogenesis; yet the most common problem in cases of bone transport with the Ilizarov technique in massive bone loss, is the long duration of the fixator. In addition to autologous bone grafting, several mechanical, biologic, and external physical treatment modalities may be employed to promote bone formation and maturation during segment transport in osteomyelitis patients. Mechanical approaches include compressive loading of the distraction regenerate, increased frequency of small increments of distraction, and compression-distraction. Intramedullary nailing and hemicorticotomy can reduce the time in external fixation; however, these techniques are associated with technical difficulties and complications. Exogenous application of low-intensity pulsed ultrasound or pulsed electromagnetic fields may shorten the duration of external fixation. Other promising modalities include diphosphonates, physician-directed use (off-label use) of bone morphogenetic proteins, and local injection of bone marrow aspirate and platelet gel at the osteotomy site. Well-designed clinical studies are needed to establish safe and effective guidelines for various modalities to enhance new bone formation during distraction osteogenesis after segment transfer.

Osteoporotic fracture and parathyroid hormone

Osteoporosis and age-related bone loss is associated with changes in bone remodeling characterized by decreased bone formation relative to bone resorption, resulting in bone fragility and increased risk of fractures. Stimulating the function of bone-forming osteoblasts, is the preferred pharmacological intervention for osteoporosis. Recombinant parathyroid hormone (PTH), PTH(1-34), is an anabolic agent with proven benefits to bone strength and has been characterized as a potential therapy for skeletal repair. In spite of PTH's clinical use, safety is a major consideration for long-term treatment. Studies have demonstrated that intermittent PTH treatment enhances and accelerates the skeletal repair process via a number of mechanisms. Recent research into the molecular mechanism of PTH action on bone tissue has led to the development of PTH analogs to control osteoporotic fractures. This review summarizes a number of advances made in the field of PTH and bone fracture to combat these injuries in humans and in animal models. The ultimate goal of providing an alternative to PTH, currently the sole anabolic therapy in clinical use, to promote bone formation and improve bone strength in the aging population is yet to be achieved.

Imaging of the anterior cruciate ligament

The anterior cruciate ligament (ACL) is an important structure in maintaining the normal biomechanics of the knee and is the most commonly injured knee ligament. However, the oblique course of the ACL within the intercondylar fossa limits the visualization and assessment of the pathology of the ligament. This pictorial essay provides a comprehensive and illustrative review of the anatomy and biomechanics as well as updated information on different modalities of radiological investigation of ACL, particularly magnetic resonance imaging.

Ultrasound-assisted musculoskeletal procedures: A practical overview of current literature

Traditionally performed by a small group of highly trained specialists, bedside sonographic procedures involving the musculoskeletal system are often delayed despite the critical need for timely diagnosis and treatment. Due to this limitation, a need evolved for more portability and accessibility to allow performance of emergent musculoskeletal procedures by adequately trained non-radiology personnel. The emergence of ultrasound-assisted bedside techniques and increased availability of portable sonography provided such an opportunity in select clinical scenarios. This review summarizes the current literature describing common ultrasound-based musculoskeletal procedures. In-depth discussion of each ultrasound procedure including pertinent technical details, indications and contraindications is provided. Despite the limited amount of prospective, randomized data in this area, a substantial body of observational and retrospective evidence suggests potential benefits from the use of musculoskeletal bedside sonography.

Diagnosing syndesmotic instability in ankle fractures

The precise diagnosis of distal tibiofibular syndesmotic ligament injury is challenging and a distinction should be made between syndesmotic ligament disruption and real syndesmotic instability. This article summarizes the available evidence in the light of the author’s opinion. Pre-operative radiographic assessment, standard radiographs, computed tomography scanning and magnetic resonance imaging are of limited value in detecting syndesmotic instability in acute ankle fractures but can be helpful in planning. Intra-operative stress testing, in the sagittal, coronal or exorotation direction, is more reliable in the diagnosis of syndesmotic instability of rotational ankle fractures. The Hook or Cotton test is more reliable than the exorotation stress test. The lateral view is more reliable than the AP mortise view because of the larger displacement in this direction. When the Hook test is used the force should be applied in the sagittal direction. A force of 100 N applied to the fibula seems to be appropriate. In the case of an unstable joint requiring syndesmotic stabilisation, the tibiofibular clear space would exceed 5 mm on the lateral stress test. When the surgeon is able to perform an ankle arthroscopy this technique is useful to detect syndesmotic injury and can guide anatomic reduction of the syndesmosis. Many guidelines formulated in this article are based on biomechanical and cadaveric studies and clinical correlation has to be established.

Ultrasound-assisted musculoskeletal procedures: A practical overview of current literature

Traditionally performed by a small group of highly trained specialists, bedside sonographic procedures involving the musculoskeletal system are often delayed despite the critical need for timely diagnosis and treatment. Due to this limitation, a need evolved for more portability and accessibility to allow performance of emergent musculoskeletal procedures by adequately trained non-radiology personnel. The emergence of ultrasound-assisted bedside techniques and increased availability of portable sonography provided such an opportunity in select clinical scenarios. This review summarizes the current literature describing common ultrasound-based musculoskeletal procedures. In-depth discussion of each ultrasound procedure including pertinent technical details, indications and contraindications is provided. Despite the limited amount of prospective, randomized data in this area, a substantial body of observational and retrospective evidence suggests potential benefits from the use of musculoskeletal bedside sonography.

Umbilical cord as a mesenchymal stem cell source for treating joint pathologies

Articular cartilage disorders and injuries often result in life-long chronic pain and compromised quality of life. Regrettably, the regeneration of articular cartilage is a continuing challenge for biomedical research. One of the most promising therapeutic approaches is cell-based tissue engineering, which provides a healthy population of cells to the injured site but requires differentiated chondrocytes from an uninjured site. The use of healthy chondrocytes has been found to have limitations. A promising alternative cell population is mesenchymal stem cells (MSCs), known to possess excellent proliferation potential and proven capability for differentiation into chondrocytes. The “immunosuppressive” property of human MSCs makes them an important candidate for allogeneic cell therapy. The use of allogeneic MSCs to repair large defects may prove to be an alternative to current autologous and allogeneic tissue-grafting procedures. An allogeneic cell-based approach would enable MSCs to be isolated from any donor, expanded and cryopreserved in allogeneic MSC banks, providing a readily available source of progenitors for cell replacement therapy. These possibilities have spawned the current exponential growth in stem cell research in pharmaceutical and biotechnology communities. Our objective in this review is to summarize the knowledge about MSCs from umbilical cord stroma and focus mainly on their applications for joint pathologies.

Delayed reconstruction of lateral complex structures of the ankle

Lateral ankle instability is one of the most common and well-recognized conditions presenting to foot and ankle surgeons. It may exist as an isolated entity or in conjunction with other concomitant pathology, making it important to appropriately diagnose and identify other conditions that may need to be addressed as part of treatment. These associated conditions may be a source of chronic pain, even when the instability has been appropriately treated, or may lead to failure of treatment by predisposing the patient to ankle inversion injuries. The primary goal of this editorial is to provide a brief summary of the common techniques used in the delayed reconstruction of lateral ankle ligamentous injuries and present a method we have successfully employed for over 15 years. We will also briefly discuss the diagnosis and treatment of the more common associated conditions, which are important to identify to achieve satisfactory results for the patient. We present the outcomes of 250 consecutive reconstructions performed over the last 10 years and describe our operative technique for addressing lateral ankle ligamentous injuries.

Interactions between the immune system and bone

The relationship between the immune system, estrogen deficiency and bone loss is an intriguing and, as yet, unexplained challenge of the past two decades. Here we summarize the evidence that links immune cells, inflammation, cytokine production and osteoclast formation and activity with particular regard to humans.

Ultrasound in the diagnosis of clinical orthopedics: The orthopedic stethoscope

Ultrasonography has advantages over other imaging modalities in terms of availability and comfort, safety, and diagnostic potential. Operating costs are low compared with both computed tomography (CT) and magnetic resonance imaging (MRI). The portable equipment is accessible at locations distant from medical centers. Importantly, ultrasonography is performed while patients lie in a comfortable position, without pain or claustrophobia. Ultrasonography is a totally safe noninvasive imaging technique. In contrast to CT and X-rays, it does not emit ionizing radiation. Unlike MRI, it is safe for all patients, including those with cardiac pacemakers and metal implants, without any contraindications. Of the many indications for musculoskeletal ultrasonography, the evaluation of soft tissue pathology is particularly common. In addition, ultrasonography is useful for the detection of fluid collection, and for visualization of cartilage and bone surfaces. Color or power Doppler provides important physiological information, including that relating to the vascular system. The capability of ultrasonography in delineating structures according to their echotextures results in excellent pictorial representation. This imaging principle is based on physical changes in composition, as compared to imaging with MRI, which is based on changes in chemical composition. This article reviews the contribution of sonography to the evaluation of the musculoskeletal system.