okoj, Volume 9, No. 8

Osteonecrosis of the Hip

Osteonecrosis of the hip is a debilitating disease that primarily affects adults in their fourth decade of life. The disease can lead to severe arthritis and can either be caused by a traumatic event or be associated with various direct or indirect risk factors. Total hip arthroplasty or hip resurfacing is indicated for patients with late-stage disease. However, alternative treatment options, including core decompression, osteotomy, and bone grafting, may improve long-term outcomes in those with less advanced disease. The key to management is early diagnosis, before collapse of the hip. The practitioner must therefore have a high degree of suspicion for the disease in patients presenting with hip pain and other factors associated with it.

    • Keywords:
    • avascular necrosis of the hip

    • AVN of the hip

    • avascular necrosis of the femoral head

    • AVN of the femoral head

    • osteonecrosis of the femoral head

    • atraumatic osteonecrosis

    • nontraumatic osteonecrosis

    • idiopathic osteonecrosis

    • core decompression

    • nonvascularized bone grafting

    • vascularized bone grafting

    • vascularized fibular grafting

    • proximal femoral osteotomy

    • transtrochanteric anterior rotational osteotomy

    • transtrochanteric posterior rotational osteotomy

    • hip resurfacing

    • total hip resurfacing

    • total hip arthroplasty

    • Subspecialty:
    • Adult Reconstruction

HOT TOPIC: Workup of the Painful Metal-on-Metal Total Hip Arthroplasty

Recent years have seen renewed interest in metal-on-metal bearing surfaces for resurfaced and total hip arthroplasties (THAs) because of the greater stability and wear resistance of these bearing surfaces compared with that of polyethylene. However, the increasing incidence of painful metal-on-metal THAs has sparked interest in such complications as adverse local tissue reactions; increased wear and metallosis from component malpositioning; and systemic metal-ion release. The relationships of these unique clinical findings to the conventional diagnoses of infection, loosening, and osteolysis in THA have become topics of active discussion in the orthopaedic community; however, the literature currently provides little information to assist in the timely clinical evaluation and management of these problems. This article provides an outline for the evaluation of patients with painful THAs and an effective plan for their treatment.

    • Keywords:
    • hip replacement

    • hip arthroplasty

    • THA

    • THR

    • hip resurfacing arthroplasty

    • metal-on-metal articulations

    • metal-on-metal bearing surfaces

    • metal-on-metal total hip articulation

    • metal-on-metal hip arthroplasties

    • cobalt-chromium ions

    • cobalt-chromium particles

    • metallosis

    • osteolysis

    • infection

    • implant loosening

    • arthroprosthetic cobaltism

    • delayed-type hypersensitivity response

    • Subspecialty:
    • Basic Science

    • Adult Reconstruction

Blount Disease

Blount disease is a growth disorder in children and adolescents characterized by a pathologic varus bowing (unilateral or bilateral) of the knees. The disease typically occurs in obese patients, and appears at two stages of life: infancy and adolescence. Treatment depends on the age of the patient and the severity of the deformity. In infantile Blount disease, a trial of bracing may be beneficial in children younger than 3 years. If there is no improvement and the disease progresses radiographically, surgical correction should be performed. In adolescent Blount disease, a progression of the deformity is likely if left untreated. Medial joint line pain is likely to worsen, and the altered forces within the joint can lead to early degenerative disease. Surgical intervention aimed at realigning the mechanical axis to potentially allow for normal medial physeal growth is therefore recommended.

    • Keywords:
    • tibia vara

    • Blount disease

    • bowleg deformity

    • varus deformity

    • valgus deformity

    • limb length discrepancy

    • rotational deformity

    • angular deformity

    • physeal growth

    • epiphysis

    • external fixation

    • tibial osteotomy

    • femoral osteotomy

    • Blount brace

    • hemiepiphysiodesis

    • epiphysiolysis

    • Subspecialty:
    • Pediatric Orthopaedics

Spondylolysis and Spondylolisthesis in the Skeletally Immature Patient

Spondylolysis and spondylolisthesis are diagnosed in ambulatory children with low back pain. Spondylolysis is a defect of the vertebral pars interarticularis, and spondylolisthesis is the anterior translation of one vertebra relative to the adjacent caudal segment. The most common forms are isthmic spondylolysis, isthmic spondylolisthesis, and stress reactions affecting the pars interarticularis. The typical patient is a child with an insidious onset of activity-related low back pain with associated hamstring tightness, without neurologic symptoms. Plain radiography and CT are useful in the diagnosis of this condition. Single-photon emission computed tomography is the single most valuable diagnostic test for spondylolysis in the presence of normal plain films. Spondylolysis and low-grade spondylolisthesis respond well to brief periods of activity modification, rest, immobilization, and physical therapy, in which case the deformity is not likely to progress. High-grade symptomatic spondylolisthesis is treated surgically, because many patients do not respond to nonsurgical treatment, and the natural history of the deformity is progressive. In situ posterolateral L5-S1 fusion is the treatment of choice for those patients with low-grade spondylolisthesis that is refractory to nonsurgical management. Pars interarticularis repair is effective for those patients with low-grade mobile spondylolisthesis or pars interarticularis defects cephalad to L5, and is considered for multilevel symptomatic spondylolysis. The optimal surgical treatment for high-grade spondylolisthesis remains controversial. Spinal fusion is recommended for patients with high-grade spondylolisthesis with or without symptoms. Traditionally, an in situ L4 through S1 fusion has been used to relieve back pain and neurologic symptoms, and to prevent continued slip progression. Reduction of the spondylolisthesis and fusion can correct sagittal spinal imbalance and permit more rapid rehabilitation. Instrumented reduction has been associated with higher rates of nerve root injury than has in situ fusion alone. The most common complications associated with surgical treatment of high-grade spondylolisthesis are pseudarthrosis and injury to the L5 nerve root.

    • Keywords:
    • acquired spondylolisthesis

    • asymptomatic spondylolysis

    • degenerative spondylolisthesis

    • developmental spondylolisthesis

    • dysplastic spondylolisthesis

    • congenital spondylolisthesis

    • high dysplastic spondylolisthesis

    • high-grade spondylolisthesis

    • isthmic (spondylolytic) spondylolisthesis

    • low dysplastic spondylolisthesis

    • low-grade spondylolisthesis

    • pathologic spondylolisthesis

    • postsurgical spondylolisthesis

    • posttraumatic spondylolisthesis

    • spondyloptosis

    • traumatic spondylolisthesis

    • Subspecialty:
    • Spine