Kyung Hoi Koo

Preventing collapse in early osteonecrosis of the femoral head. A randomised clinical trial of core decompression

We performed a randomised trial on 37 hips (33 patients) with early-stage osteonecrosis (ON). After the initial clinical evaluation, including plain radiography and MRI, 18 hips were randomly assigned to a core-decompression group and 19 to a conservatively-treated group. All the patients were regularly followed up by clinical evaluation, plain radiography and MRI at intervals of three months. Hip pain was relieved in nine out of ten initially symptomatic hips in the core-decompression group but persisted in three out of four initially painful hips in the conservatively-treated group at the second assessment (p < 0.05). At a minimum follow-up of 24 months, 14 of the 18 core-decompressed hips (78%) and 15 of the 19 non-operated hips (79%) developed collapse of the femoral head. By survival analysis, there was no significant difference in the time to collapse between the two groups (log-rank test p = 0.79). Core decompression may be effective tin symptomatic relief, but is of no greater value than conservative management in preventing collapse in early osteonecrosis of the femoral head.

Angiography, Scintigraphy, Intraosseous Pressure, and Histologic Findings in High-Risk Osteonecrotic Femoral Heads With Negative Magnetic Resonance Images

One hundred twenty-six hips of 68 patients who were suspected of having osteonecrosis or being at risk for osteonecrosis were studied with magnetic resonance (MR) imaging. Abnormal patterns on MR imaging characteristic of osteonecrosis were observed in 98 hips. The remaining 28 hips (22 patients) with negative MR images underwent superselective angiography of the medial femoral circumflex artery. Angiography showed interruption of the superior retinacular arteries in 13 hips (12 patients), including 6 of 7 symptomatic hips. Bone scans were performed on 8 of 13 hips angiographically positive for osteonecrosis. Decrease of radionuclide uptake (cold lesions) was observed in all 8 of these femoral heads. Thirteen femoral heads with interruption of superior retinacular arteries underwent intraosseous pressure measurement and core biopsy. Intraosseous pressure was elevated in 11 hips. The results of histologic study showed evidence of early necrosis in 10 femoral heads. This study indicates that there are a considerable number of femoral heads at high risk, even when they have negative MR images. They do, however, show positive findings on angiography, scintigraphy (cold lesions), intraosseous pressure measurement, and histologic study.

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.

Morphologic and biomechanical study of avascular necrosis of the femoral head

Radiologic review and uniaxial compression tests of 1 cm3 cubes of avascular and subjacent portions of 64 femoral heads of 51 patients with idiopathic avascular necrosis of the femoral head were performed to determine the morphologic and biomechanical changes with progression of the disease. Cases were divided into three groups according to the simple radiographic findings: group I (precollapse), group II (collapse), and group III (advanced collapse with secondary degenerative arthritis). Fourteen group I, 36 group II, and 14 group III specimens were identified. In addition to the simple radiographs, 16 magnetic resonance images were reviewed. In group I, there was no significant difference of yield and maximum stress, and modulus of elasticity between avascular and subjacent portions below the reactive rim. In group II, the above parameters showed lower values in the avascular portion than in the subjacent portion (P less than .05). In group III, maximum stress of the avascular portion showed significantly higher value than that of the subjacent region (P less than .05). In groups II and III, a major crack was observed in the subchondral area in 14 specimens and in the deep avascular and reactive junction in 36 specimens. Bone densitometry data suggested higher mineral content indicative of more sclerosis in the deep crack group. These findings might suggest that different biomechanical properties in the subchondral crack group and interface crack group might contribute to varieties in clinical manifestations. Later sclerotic changes and aspherical collapse of the femoral head might play a large role in the development of secondary degenerative arthritis of the hip joint.

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.

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.

Comparison of MRI with subchondral fracture in the evaluation of extent of epiphyseal necrosis in the early stage of Legg-Calvé-Perthes disease.

We reviewed 20 patients in the early stage of Legg-Calvé-Perthes disease who showed a subchondral fracture line in radiographs. All 20 patients underwent magnetic resonance imaging (MRI) within 2 months after the first symptoms. Follow-up MRI after treatment was performed in 10 patients. The subchondral fracture line in radiographs and serial T1-weighted image was used to measure the extent of the epiphyseal necrosis volumetrically. These extents in the early stage were compared with those in the late stage for determination of prognostic significance. The intensities of coronal MRIs under the subchondral fracture were not homogeneous. The uninvolved epiphysis also showed nonhomogeneous intensities because the posterior column revealed higher intensity compared with the anterior column. The extent of the subchondral fracture line is more accurate in predicting the amount of eventual necrosis than is the extent of necrosis in MRI, which does not have a consistent correlation.

Treatment of antecubital pterygium in the nail-patella syndrome.

Antecubital pterygium is rare in the nail-patella syndrome but common in the multiple pterygium syndrome and aplasia of the trochlea. It is known that there is the rebound phenomenon after treatment of congenital joint contracture. We describe the poor functional results due to rapid recurrence of the flexion contracture treated with the Ilizarov method for an antecubital pterygium in the nail-patella syndrome.

Spontaneous healing of an atrophic pseudoarthrosis during femoral lengthening. A case report with six-year follow-up

Abstract A seven-year old girl developed an atrophic pseudoarthrosis at the midshaft of the femur with 8.5 cm of femoral shortening after an open type II fracture. During a femoral lengthening procedure, the pseudoarthrosis filled with spontaneous callus formation and bone union was obtained.Résumé Une fille âgée de 7 ans 8 mois a développé une pseudarthrose atrophique médiodiaphysaire du fémur à la suite d’une fracture ouverte de type II. Le raccourcissement fémoral a finalement été de 8,5 cms. L’allongement fémoral a permis le comblement de la zone de pseudarthrose par un cal spontané avec une bonne consolidation osseuse.