Hae Ryong Song

Role of thrombotic and fibrinolytic disorders in the etiology of Perthes' disease.

The etiologic role of thrombotic and fibrinolytic disorders in Perthes’ disease has not been determined. A case control study was conducted to determine whether thrombotic and fibrinolytic disorders are associated with Perthes’ disease. Twenty-six patients with Perthes’ disease were matched with 26 control patients for gender, age (2-year range), and time of presentation (1-year range). Thrombotic disorders were investigated for protein C activity, protein S activity, antithrombin III, anticardiolipin antibody immunoglobulins G and M, and lupus anticoagulant. Fibrinolytic disorders were investigated for tissue-plasminogen activator, plasminogen activator inhibitor-1, plasminogen activator inhibitor-1 to tissue plasminogen activator ratio, lipoprotein (a), and plasminogen. The activity of protein C, which suppresses factor Va and leads to an increase of coagulant activity when decreased, was increased in patients. There were no significant differences in the levels of other factors between the patients and controls. No evidence was found to prove a relationship between Perthes’ disease and thrombotic or fibrinolytic disorders in the patients in the current study.

Spondyloepiphyseal dysplasia congenita with absent femoral head.

Spondyloepiphyseal dysplasia congenita (SEDC), an inherited chondrodysplasia, occurs through a mutation in the COL2A1 gene encoding the type II procollagen alpha1 chain, proalpha1 (II). Recently, the authors studied two Korean patients with SEDC. Both these patients had short stature, os odontoideum with or without atlantoaxial instability, platyspondyly, and epiphyseal dysplasia limited to the femoral heads. The more seriously affected patient had shorter height (125 cm), atlantoaxial instability associated with os odontoideum, flat feet, and cleft palate, absence of the femoral head on radiographic and magnetic resonance imaging (MRI), and dislocated proximal femur. The less seriously affected patient was taller (145 cm) and had no atlantoaxial instability, absence of the femoral head on radiography with visible cartilage anlage on MRI, and subluxated cartilaginous femoral head. A mutation analysis was performed using direct sequencing. Two novel dominant mutations were found in the COL2A1 gene of these two patients: G277V and G238S, respectively. Although glycine was substituted with valine and serine in the proalpha1 (II) of these two patients, their phenotypes were significantly different in physical and radiologic evaluations.

Classification of metaphyseal change with magnetic resonance imaging in Legg-Calvé-Perthes disease.

Seventy-eight patients (85 affected hips and 71 unaffected hips) with Legg-Calvé-Perthes disease were included in this study to evaluate the metaphyseal change in radiographs and magnetic resonance imaging (MRI) and to define the type of the metaphyseal cyst according to presence or absence of the epiphyseal involvement. The content of the metaphyseal cyst was evaluated by using T1, T2, proton, and gadolinium-enhanced T1-weighted MRI scans. Among 85 hips, there were no changes in 32 hips, marrow edema in 13 hips, false cyst with epiphyseal involvement in 28 hips, and true cyst without epiphyseal involvement in 12 hips. Granulation tissue was found in the false cysts and water-rich fibrotic tissue was found in the true cysts based on the MRI scans. The metaphyseal change in MRI scans was shown in 71% of groups 3 and 4 and in 35% of groups 1 and 2 according to the Catterall classification, and 52% of group A, 56% of group B, and 86% of group C according to the Herring classification. Of the 30 hips at the avascular stage, 33% showed metaphyseal cyst in MRI scans. Of the 53 hips at the fragmentation stage, 60% showed the metaphyseal cyst.

Injected calcium sulfate for consolidation of distraction osteogenesis in rabbit tibia.

This study investigated the effects of calcium sulfate powder injection in a rabbit tibial distraction model. There was one experimental group and two control groups. The calcium sulfate powder, suspended in carboxymethylcellulose (CMC) medium, was injected into the distracted tissue in the experimental rabbit group, whereas only CMC medium was injected into the one control group. The other control group did not undergo any intervention. On radiography and bone mineral density tests, the amount of newly formed bone was greater in the distracted zone of the experimental group than in the two control groups, which showed incomplete bone deposition and calcification. The application of calcium sulfate to distracted tissue increased the rate of osteogenesis and calcification.

Subcapital fractures associated with extensive osteonecrosis of the femoral head.

The authors reviewed 10 patients with subcapital fractures associated with extensive osteonecrosis of the femoral head and distinguished these fractures from traumatic femoral neck fractures. The mean age of the patients was 52 years (range, 36–68 years). Nine patients were younger than 60 years. Eight patients had risk factors for osteonecrosis. Necrosis was extensive and involved nearly the whole femoral head. Fracture occurred at the junction between a necrotic bone and reparative bone and extended downward through the reparative interface to the healthy inferior cortex of the femoral neck. Patients experienced hip pain that was aggravated gradually during a period of 1 to 24 weeks before diagnosis of the fracture. In all patients, the opposite femoral head was involved with osteonecrosis. In two femoral heads, slight collapse or subchondral fracture (crescent sign) also was observed. No patient had a history of precipitating trauma. In patients younger than 60 years with a subcapital fracture, fracture associated with extensive osteonecrosis of the femoral head should be suspected when a history of trauma is not obvious, when the opposite hip shows findings of osteonecrosis, and when the patient has a risk factor of osteonecrosis. In these fractures, osteosynthesis rarely should be considered because of the high failure rate caused by additional progression of extensive osteonecrosis and the probability of nonunion.

Spontaneous Bone Regeneration in Surgically Induced Bone Defects in Young Rabbits

Defects of the femoral shaft (15%, 20%, 25%, and 30% of the femoral length) with intact periosteum were made in young rabbits to investigate differences in union time. The mean union time was 7.3, 7.1, 7.4, and 7.0 weeks, respectively and there was no significant difference (P >0.05) between the groups. The mean healing indices were 6.7, 4.6, 3.9, and 3.1 weeks/cm, respectively and these were significantly different (P <0.05) between the 15% bone defect group and the other bone defect groups. These results suggested that union time was not affected by the amount of bone defect. Femoral lengthening of 20% was performed to compare the quality of callus with those of the femoral defect of 20%. The mean healing indices of defect and lengthening were 4.6 and 5.7, respectively and the difference was significant (P = 0.004). The callus stiffness of femoral defect was higher (P = 0.02) than that after femoral lengthening whereas the bone mineral density of the callus showed no significant difference (P = 0.37) between two groups. The method of filling bone defect with callus generated from the intact periosteum may be a new therapeutic option for the reconstruction of large bone defects in children when other treatments are not available.