Core Decompression plus Autologous Mesenchymal Stem Cell Transplantation for Treating Early-stage Femoral Head Necrosis

Osteonecrosis; traumatic osteonecrosis; atraumatic osteonecrosis; avascular necrosis; aseptic necrosis; ischemic necrosis; core decompression (CD); bone grafting; autologous mesenchymal stem cells; bone marrow stem cells; adipose stem cells; mesenchymal stem cells (MSCs); skeletal stem cells; multipotent mesenchymal stromal cells

Avascular necrosis, or osteonecrosis, is death of bone tissue due to reduced blood flow. The two forms of osteonecrosis are traumatic (most common) and atraumatic.1 Osteonecrosis of the hip typically affects the femoral head, and once blood supply to the femoral head declines below a threshold level, cell death can follow.2 As the osteocytes die, the bone structure of the femoral head collapses and fractures, resulting in pain and loss of joint function. During the end stage of the disease, severe destruction of the femoral head with concomitant hip degeneration occurs.1

Etiology

Both traumatic (i.e., femoral neck fracture, hip dislocation, subluxation) and atraumatic (i.e., alcoholism, coagulation disorder, liver disease, corticosteroids) clinical factors are associated with osteonecrosis development.1,2 The pathophysiology of osteonecrosis remains unknown. Histologists have reported the presence of dead osteocytes in the initial disease stages.1 Dead osteocytes signal the natural repair process; osteoclasts resorb the necrotic bone, and osteoblasts form new bone. For smaller lesions, natural repair may stop disease progression. Yet for larger lesions, the disease can progress. Along the lesion periphery, osteoblasts create new bone, but the central region is avascular (slow to heal), more prone to fracture or further injury, and ultimately may collapse inward.1 Collapse of this outer necrotic bony segment manifests as having the appearance of a "crescent sign" on radiograph and is the first indication of impending femoral head collapse.

Staging/Classification

Osteonecrosis typically presents as a painful hip, often localized to the groin, buttocks, and hip area.1 Most patients report a slow-onset groin pain (bilateral or unilateral) that increases with exercise or weight-bearing activity.3 Range of motion may be limited, yet results of initial radiographs could be normal. Thus, diagnosis must be confirmed by magnetic resonance imaging (MRI).4 Because there are marked differences in disease progression, and since treatment options vary based on disease stage, classifying the disease stage is useful. Use of MRI and bone scan for diagnosis has enabled clinicians to stage osteonecrosis of the hip using three different classification schemes: Ficat/Arlet, Steinberg, and Association Research Circulation Osseous (ARCO). See...