JAAOS

JAAOS, Volume 14, No. 12


Applications of porous tantalum in total hip arthroplasty.

Porous tantalum is an alternative metal for total joint arthroplasty components that offers several unique properties. Its high volumetric porosity (70% to 80%), low modulus of elasticity (3 MPa), and high frictional characteristics make it conducive to biologic fixation. Tantalum has excellent biocompatibility and is safe to use in vivo. The low modulus of elasticity allows for more physiologic load transfer and relative preservation of bone stock. Because of its bioactive nature and ingrowth properties, tantalum is used in primary as well as revision total hip arthroplasty components, with good to excellent early clinical results. In revision arthroplasty, standard and custom augments may serve as a structural bone graft substitute. Formation of a bone-like apatite coating in vivo affords strong fibrous ingrowth properties and allows for substantial soft-tissue attachment, indicating potential for use in cases requiring reattachment of muscles and tendons to a prosthesis. Development of modular components and femoral stems also is being evaluated. The initial clinical data and basic science studies support further investigation of porous tantalum as an alternative to traditional implant materials.

    • Keywords:
    • Animals|Arthroplasty

    • Replacement

    • Hip|Hip Prosthesis|Humans|Osteoarthritis

    • Hip|Porosity|Prosthesis Design|Tantalum

    • Subspecialty:
    • Adult Reconstruction

Malignant tumors of the hand and wrist.

Malignant tumors in the hand and wrist compose a wide variety of lesions involving skin, soft tissues, and bone. Although these lesions are found elsewhere in the body, many have unique characteristics at this anatomic location. Skin tumors predominate; the most common are squamous cell carcinomas, followed in frequency by basal cell carcinomas and malignant melanomas. Other soft-tissue malignancies are less common but may present more difficult diagnostic problems. They often appear as painless masses that sometimes have been present for months or even years and deceptively appear to be benign. A missed or delayed diagnosis of these tumors can have devastating consequences. Bone malignancies involve both primary lesions, of which chondrosarcomas are the most common, and metastatic lesions. Regardless of cell type, treatment of malignant tumors in the hand and wrist requires special considerations because of the important function of these structures. Orthopaedic surgeons should be familiar with the spectrum of these tumors, the work-up necessary to arrive at a precise diagnosis, and the treatment that will achieve the most favorable outcome.

    • Keywords:
    • Bone Neoplasms|Diagnosis

    • Differential|Hand|Humans|Orthopedic Procedures|Prognosis|Soft Tissue Neoplasms|Wrist

    • Subspecialty:
    • Hand and Wrist

    • Musculoskeletal Oncology

Patient-centered care.

    • Keywords:
    • Clinical Competence|Decision Making|Humans|Orthopedics|Patient-Centered Care|Physician-Patient Relations

    • Subspecialty:
    • Clinical Practice Improvement

Sacral fractures.

Sacral fractures most commonly occur after pelvic ring injuries but occasionally in isolation. Although the true incidence of sacral fractures is unknown, an estimated 30% are identified late. Sequelae of inappropriately treated or untreated sacral fractures include persistent pain, decreased mobility, and neurologic compromise. Because these fractures often result from high-energy trauma, concomitant injuries should be suspected. A thorough physical examination, including a detailed neurologic assessment and radiographic evaluation, is necessary to determine treatment. Computed tomography of the pelvis/sacrum can provide significant information about fracture pattern. Surgical intervention, often as a combination of neural decompression and stabilization, is indicated in patients with neurologic deficits, significant soft-tissue compromise, and lumbosacral instability. Patient satisfaction with surgical intervention has not been definitively documented, although neurologic improvement with timely intervention has been noted.

    • Keywords:
    • Fracture Fixation|Humans|Sacrum|Spinal Fractures|Tomography

    • X-Ray Computed

    • Subspecialty:
    • Trauma

    • Spine

Slipped capital femoral epiphysis: current concepts.

Slipped capital femoral epiphysis is a common hip disorder in adolescents, with an incidence of 0.2 (Japan) to 10 (United States) per 100,000. The etiology is unknown, but biomechanical and biochemical factors play an important role. Symptoms at presentation include pain in the groin, thigh, or knee. Ambulatory patients also may present with a limp. Nonambulatory patients present with excruciating pain. The slipped capital femoral epiphysis is classified as stable when the patient can walk and unstable when the patient cannot walk, even with the aid of crutches. Because the epiphysis slips posteriorly, it is best seen on lateral radiographs. The treatment of choice for stable slipped capital femoral epiphysis is single-screw fixation in situ. This method has a high probability of long-term success, with minimal risk of complications. In the patient with unstable slipped capital femoral epiphysis, urgent hip joint aspiration followed by closed reduction and single- or double-screw fixation provides the best environment for a satisfactory result, while minimizing the risk of complications.

    • Keywords:
    • Epiphyses|Epiphyses

    • Slipped|Femur|Humans|Orthopedic Procedures

    • Subspecialty:
    • Pediatric Orthopaedics

    • Basic Science

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