JAAOS, Volume 12, No. 2

Low back pain: pathophysiology and management.

Basic research is advancing the understanding of the pathogenesis and management of low back pain at the molecular and genetic levels. Frequently, low back pain is caused by disorders of the intervertebral disk. Cytokines such as matrix metalloproteinases, phospholipase A2, nitric oxide, and tumor necrosis factor-alpha are thought to contribute to the development of low back pain. Drugs are being developed to modulate these chemical mediators. Recent research using growth factors to promote chondrocyte regeneration appears to be promising. Advances in gene therapy to both prevent disk degeneration and regenerate the disk eventually may have clinical application.

    • Keywords:
    • Analgesics|Chronic Disease|Combined Modality Therapy|Female|Humans|Intervertebral Disk|Intervertebral Disk Displacement|Low Back Pain|Male|Manipulation

    • Spinal|Physical Therapy Modalities|Prognosis|Risk Assessment|Severity of Illness Index|Spinal Fusion|Treatment Outcome

    • Subspecialty:
    • Pain Management

    • Spine

Heterotopic ossification.

Heterotopic ossification, the formation of bone in soft tissue, requires inductive signaling pathways, inducible osteoprogenitor cells, and a heterotopic environment conducive to osteogenesis. Little is known about the molecular pathogenesis of this condition. Research into two rare heritable and developmental forms, fibrodysplasia ossificans progressiva and progressive osseous heteroplasia, has provided clinical, pathologic, and genetic insights. In fibrodysplasia ossificans progressiva, overexpression of bone morphogenetic protein 4 and underexpression of multiple antagonists of this protein highlight the potential role of a potent morphogenetic gradient. Research on fibrodysplasia ossificans progressiva also has led to the identification of the genetic cause of progressive osseous heteroplasia: inactivating mutations in the alpha subunit of the gene coding for the stimulatory G protein of adenylyl cyclase. Better understanding of the complex developmental and molecular pathology of these disorders may lead to more effective strategies to prevent and treat other, more common forms of heterotopic ossification.

    • Keywords:
    • Adolescent|Adult|Age Distribution|Bone Morphogenetic Proteins|Child|Child

    • Preschool|Disease Progression|Female|Follow-Up Studies|Gene Expression|Genetic Predisposition to Disease|Humans|Incidence|Male|Myositis Ossificans|Ossification

    • Heterotopic|Risk Assessment|Severity of Illness Index|Sex Distribution

    • Subspecialty:
    • Pediatric Orthopaedics

Sports for the physically challenged child.

Participation in sports is important for the physical and emotional health of the physically challenged child. Sports can improve strength, endurance, and cardiopulmonary fitness while providing companionship, a sense of achievement, and heightened self-esteem. With interest in such participation increasing, it is necessary for the physicians, therapists, and families of children with special needs to understand the preparticipation evaluation, athletic options, specialized equipment, and sport-specific risks. Recommendations that provide guidelines for safe, effective participation in sports are currently available for common congenital and developmental disabilities such as Down syndrome, cerebral palsy, myelodysplasia, hemophilia, congenital amputations, and arthritic disorders.

    • Keywords:
    • Adolescent|Cerebral Palsy|Child|Child

    • Preschool|Developmental Disabilities|Disability Evaluation|Down Syndrome|Female|Follow-Up Studies|Humans|Male|Neural Tube Defects|Physical Education and Training|Risk Assessment|Sports

    • Subspecialty:
    • Sports Medicine

    • Pediatric Orthopaedics

Parathyroid hormone.

    • Keywords:
    • Aged|Alendronate|Bone Density|Bone Remodeling|Clinical Trials as Topic|Dose-Response Relationship

    • Drug|Etidronic Acid|Female|Follow-Up Studies|Fractures

    • Spontaneous|Humans|Male|Middle Aged|Osteoporosis|Osteoporosis

    • Postmenopausal|Parathyroid Hormone|Risk Assessment|Teriparatide|Treatment Outcome

    • Subspecialty:
    • General Orthopaedics

Implanted neuroprostheses for restoration of hand function in tetraplegic patients.

Restoration of hand function through functional electrical stimulation allows tetraplegic patients to use existing abilities to control paralyzed muscles. In patients with C5 or C6 spinal cord injuries, implanted upper extremity neuroprostheses use functional electrical stimulation technology to power hand and arm muscles. A variety of devices, often using contralateral shoulder motion, sends signals via a small external controller and transmitting coil to an implanted stimulator. The stimulator powers designated upper extremity muscles via implanted electrodes. The surgical procedure is minimally invasive and easily reversed. Palmar and lateral grasp, among other functions, can be reliably restored, leading to significant improvements in functional capacity. High user satisfaction, low complication rates, and recent advances in technology and control systems contribute to the success of this technology in the treatment of devastating spinal cord injuries.

    • Keywords:
    • Electric Stimulation|Electrodes

    • Implanted|Female|Humans|Male|Patient Selection|Prosthesis Design|Quadriplegia|Range of Motion

    • Articular|Recovery of Function|Spinal Cord Injuries|Upper Extremity

    • Subspecialty:
    • Hand and Wrist

Evidence-based medicine.

Evidence-based medicine refers to an explicit process of using and evaluating information to make medical decisions. Evidence-based medicine, perhaps contrary to popular perception, requires its users to embrace uncertainty in medical decision making because information that is simultaneously true and complete cannot be attained. Recognizing medicine's inherent uncertainty, proponents of evidence-based medicine advocate using a five-step process for sound decision making: formulate answerable questions, gather evidence, appraise the evidence, implement the valid evidence, and evaluate the process. The formulation of answerable questions requires categorizing the facts of the case in terms that allow comparison to evidence gathered from prior studies. The appraisal of the evidence uses the tools of clinical epidemiology to assess the validity and applicability of the evidence. Implementation refers to the construction of a clinical plan based on the evidence collected as well as on the physician's judgment and patient's preferences. Finally, evidence-based medicine requires continued evaluation and refinement. The methods of evidence-based medicine are especially germane to contemporary medicine as physicians practice under increasing demands to deliver optimal outcomes yet face an ever-expanding body of medical knowledge.

    • Keywords:
    • Case-Control Studies|Evidence-Based Medicine|Female|Forecasting|Humans|Male|Orthopedics|Randomized Controlled Trials as Topic

    • Subspecialty:
    • Clinical Practice Improvement

Metaphyseal fibrous defects.

Nonossifying fibromas and fibrous cortical defects are the most common benign lesions of the skeletal system. They are frequently detected incidentally on radiographs taken for an unrelated reason. The diagnosis is routinely made solely on the basis of the history, physical examination, and radiographic appearance. The incidence of multifocal nonossifying fibroma is typically underestimated in patients initially found to have a solitary lesion; the use of a limited skeletal survey rather than bone scan may help detect multifocal lesions in this population. Small, asymptomatic lesions may be followed over time using serial radiographs. Incisional biopsy, curettage, and bone grafting are indicated for large lesions that raise concern for impending pathologic fracture, for lesions that have become painful, and for lesions whose characteristics prevent a definitive radiographic diagnosis. Pathologic fractures involving these lesions should be treated with cast immobilization until the fracture has healed, followed by biopsy, curettage, and bone grafting.

    • Keywords:
    • Adolescent|Adult|Age Distribution|Biopsy

    • Needle|Bone Neoplasms|Child|Combined Modality Therapy|Female|Fibroma|Fractures

    • Spontaneous|Humans|Immunohistochemistry|Male|Prevalence|Prognosis|Risk Assessment|Sex Distribution|Tomography

    • X-Ray Computed

    • Subspecialty:
    • Musculoskeletal Oncology

Management of Ficat stage III and IV osteonecrosis of the hip.

Management of Ficat stage III and IV osteonecrosis of the hip remains controversial. Because patients usually require a surgical intervention in their mid 30s, the initial procedure is often the first step in a lifelong treatment plan. Long-term results of total hip arthroplasty in these young, active patients have been disappointing. New alternative bearing surfaces (metal-on-metal, ceramic-on-ceramic, and highly cross-linked polyethylene) and improved methods of fixation may lead to better long-term results. Nevertheless, bone- and joint-preserving procedures, such as free-vascularized fibular graft, trapdoor grafting, redirectional osteotomy, or hemiresurfacing hip arthroplasty, should be considered. The choice of option depends on patient age, the cause of osteonecrosis, the extent of femoral head involvement, and the condition of the acetabular articular cartilage. The goals of treatment are to relieve pain, improve function, minimize morbidity, and maintain options for secondary procedures.

    • Keywords:
    • Adult|Age Factors|Arthroplasty

    • Replacement

    • Hip|Bone Transplantation|Female|Femur Head Necrosis|Hip Joint|Humans|Male|Middle Aged|Osteotomy|Pain Measurement|Prognosis|Prosthesis Design|Range of Motion

    • Articular|Recovery of Function|Risk Assessment|Severity of Illness Index|Treatment Outcome

    • Subspecialty:
    • Adult Reconstruction