Hyoung Yeon Seo

Significance of laboratory and radiologic findings for differentiating between septic arthritis and transient synovitis of the hip.

Although significant differences exist in the methods of treatment and prognoses of septic coxitis and transient synovitis in children complaining of acute hip pain, similar symptoms are present in these two diseases at the early stages, and differential diagnosis is difficult. To differentiate between these two diseases, the authors evaluated the clinical, serologic, and radiologic findings and tried to determine factors that could be used as diagnostic criteria. The authors performed a retrospective study by evaluating medical records, plain hip radiographs, and clinical findings in 97 patients with transient synovitis and 27 patients with septic arthritis. Univariate analysis showed significant differences in body temperature, serum WBC count, and ESR and CRP levels of the two patient groups. Plain radiographs showed a displacement or blurring of periarticular fat pads in all patients with acute septic arthritis, and multivariate regression analysis showed that body temperature >37°C, ESR >20 mm/h, CRP >1 mg/dL, WBC >11,000/mL, and an increased hip joint space of >2 mm were independent multivariate predictors of acute septic arthritis. The authors conclude that the independent multivariate predictors are effective indices for the differential diagnosis of acute septic coxitis and transient synovitis.

Differentiation of intervertebral notochordal cells through live automated cell imaging system in vitro

Study Design. We demonstrated the differentiation of notochordal cells by direct observation using a live automated cell imaging system. We also hypothesized that notochordal cells have characteristics of chondrocyte-like cells. Objective. To determine characteristics of notochordal cells by matrix protein expression and their differentiation using a live automated cell imager. Summary of Background Data. Although notochordal cells are critical to homeostasis of intervertebral disc, their fate has not been extensively studied and there is little evidence of notochordal cells as progenitors. Methods. Notochordal cells purified from rabbit nucleus pulposus were isolated after serial filtration. Notochordal cells in 3-dimensional culture were compared to chondrocyte-like cells by 35S sulfate incorporation into proteoglycan and reverse transcription polymerase chain reaction for gene expression(collagen II and aggrecan). Notochordal cells in 2-D culture were used for immunocytochemical staining (collagen II, aggrecan, and SOX9) and time-lapsed cell tracking study. Results. Notochordal cells were capable of proteoglycan production at a rate comparable to chondrocyte-like cells (108% ± 22.6% to chondrocyte-like cells) and expressed collagen II, aggrecan, and SOX9. In time-lapsed cell tracking analysis, notochordal cells were slower in population doubling time than chondrocyte-like cells and differentiated into 3 morphologically distinct cell types: vacuolated cells (area: 2392 ± 507.1 &mgr;m2, velocity: 0.09 ± 0.01 &mgr;m/min); giant cells (area: 12678 ± 1637.0 &mgr;m2, velocity: 0.08 ± 0.01 &mgr;m/min) which grew rapidly without cell division; polygonal cells (area: 3053 ± 751.2 &mgr;m2, 0.14 ± 0.01 &mgr;m/min) morphologically similar to typical differentiation type of chondrocyte-like cells (area: 2671 ± 235.6 &mgr;m2, 0.19 ± 0.01 &mgr;m/min). Rarely, notochordal cells formed clusters analogous to that observed in vivo. Conclusion. These studies demonstrate a chondrocyte phenotype of notochordal cells and are the first direct evidence of notochordal cell differentiation, suggesting that they may act as progenitor cells, which has the potential to lead to their use in novel approaches to regeneration of degenerative intervertebral disc.

In Vivo Stability and Clinical Comparison of Anterior Cruciate Ligament Reconstruction Using Low or High Femoral Tunnel Positions

Background: Several biomechanical studies have supported placing the femoral tunnel at a low position (10 or 2 o’clock) to achieve anterior and rotational knee stabilities after anterior cruciate ligament (ACL) reconstruction. However, no firm consensus has been reached regarding the merits and demerits of ACL reconstruction using a low femoral tunnel versus a high femoral tunnel (11 or 1 o’clock). Hypothesis: A low femoral tunnel position during ACL reconstruction provides better intraoperative stability (especially, rotational stability) and clinical outcomes than does a high femoral tunnel position. Study Design: Cohort study; Level of evidence 2. Methods: Sixty-two patients who underwent ACL reconstruction were equally allocated to low and high femoral tunnel groups; 58 were followed up for a minimum of 2 years (29 in the each group). After reconstruction and using a navigation system, the authors compared intraoperative anterior, internal rotational, and external rotational stabilities at 0°, 30°, 60°, and 90° of knee flexion and compared clinical outcomes, including Lysholm knee scores, Tegner activity scores, Lachman and pivot-shift test findings, and radiographic stabilities at final follow-up visits. Results: The low group showed significantly better intraoperative internal rotational stability at 0° and 30° of flexion but not at other angles (60° and 90°). Intraoperatively, no significant intergroup differences were found for anterior and external rotational stabilities at any flexion angle. Furthermore, clinical outcomes, including Lysholm knee and Tegner activity scores, showed no significant differences between the 2 groups at final follow-up visits (P > .05), and Lachman and pivot-shift test stability results and radiological stability data obtained at final follow-up were not significantly different between the 2 groups (P > .05). Conclusion: The low femoral tunnel group showed better internal rotational stability at time zero during ACL reconstruction but similar anterior and external rotational stabilities. No significant differences were observed between the 2 groups in terms of clinical outcomes and stabilities after a minimum follow-up of 2 years.

Tibial plateau stress fracture after unicondylar knee arthroplasty using a navigation system: two case reports

Satisfactory alignments of components in total knee arthroplasty have been reported since the introduction of navigation systems. And thus, such techniques have been introduced for minimally invasive unicondylar knee arthroplasty (UKA). Several intraoperative fractures of the tibial plateau have been reported in association with minimally invasive UKA and some stress fractures of tibial plateau associated with design of instrument have been reported. Here, we report on two cases of stress fracture of the tibial medial plateau after minimally invasive UKA was performed using a navigation system.

Expression and Significance of TGF-β Isoform and VEGF in Osteosarcoma

This article demonstrates that the degree of VEG expression could be used as a clinically signific prognostic factor in osteosarcoma.

Hi-Flexion and Gender-Specific Designs Fail to Provide Significant Increases in Range of Motion During Cruciate-Retaining Total Knee Arthroplasty

The effects of different femoral component designs on intraoperative range of motion were examined in 40 female patients during primary cruciate-retaining (CR) total knee arthroplasty. After complete bone resection and soft tissue balancing, standard CR, high-flexion, and gender-specific knee trials were sequentially inserted, and maximal flexion and extension under gravity were measured using a navigation system. Average maximal flexions were 134.3° for standard CR knees, 136.2° for high-flexion knees, and 136.4° for gender-specific knees. No significant intergroup differences in intraoperative maximal flexion and extension were found (P > .05). High-flexion and gender-specific femoral designs were found to show subtle increases in intraoperative range of motion as compared with the standard design but no significant differences.

New two-incision minimally invasive total hip arthroplasty: comparison with the one-incision method

BackgroundThere has been increasing interest in performing total hip arthroplasty (THA) with minimally invasive surgery (MIS). This study was conducted to examine the effectiveness of MIS-THA using the new two-incision technique versus the one-incision technique.MethodsA consecutive series of 113 patients who underwent MIS-THAs (63 one-incision cases, 50 two-incision cases) were studied. One-incision THA was performed with a posterolateral approach. For the two-incision, the first incision for cup insertion was made over the anterolateral side of the hip. Intermuscular dissection was performed between the gluteus medius and the tensor fascia lata. The second incision, for stem insertion, was made on the posterolateral side of the hip along the fiber of the gluteus maximus. Intermuscular dissection was made between the gluteus medius and the piriformis.ResultsPostoperative rehabilitation was significantly more rapid in the new two-incision group compared to the group with one incision. Postoperatively, the Harris Hip Score and the Western Ontario and the McMaster Universities Osteoarthritis Index score were significantly different between the two groups, especially the functional sections.ConclusionsThe findings of this study show that our new two-incision MIS-THA is an excellent surgical modality that allows early rehabilitation.

An unusual case of pulmonary embolism after arthroscopic meniscectomy.

Although the incidence of pulmonary embolism (PE) following arthroscopic knee surgery has not been well established, such occurrences place the patient at high risk. In this report we present a case of PE following arthroscopic meniscectomy. The patient was a 63-year-old woman, with no definite risk factors for PE, who underwent successful arthroscopic meniscectomy. However, on the postoperative 9th day she developed dyspnea and tachycardia. Investigations carried out in the emergency department, including EKG, echocardiography, and CT angiography, supported the diagnosis of a PE. Heparin therapy was initiated, and the patient’s condition then improved sufficiently to allow follow-up at our outpatient department.

Deformity of the femoral head following vascular infarct in piglets.

Background In Legg-Calvé-Perthes disease (LCPD), 4 major patterns (coxa plana, coxa magna, coxa vara, subluxation) of the femoral head are commonly observed. However, direct observation of pathological specimens is rarely possible. An animal model of LCPD may clarify the pathogenesis of femoral head deformity. Animals and methods In 26 piglets, we interrupted the vascular supply to the capital femoral epiphysis by cutting the ligamentum teres and ligating the femoral neck containing the epiphyseal artery. 6–7 piglets in each experimental group were killed at early (2 and 4 weeks: P2 and P4), intermediate (12 weeks: P12), and late (20 weeks: P20) periods. We examined the extracted femoral heads macroscopically and radiographically. Results The mean decrease in epiphyseal height was 1.5 mm, 4.1 mm, 5.0 mm, and 7.5 mm in P2, P4, P12 and P20, respectively (rs = 0.76, p = 0.002). The mean increase of diameter was 4.1 mm, 6.9 mm, and 6.8 mm in P4, P12 and P20, respectively. Decrease of the articulotrochanteric distance was mild in P2 and P4, and severe in P12 and P20. Subluxation of the femoral head was observed only in P12 and P20 piglets. Interpretation The piglet model of LCPD was useful in the early stage of devascularization for investigation of the developmental pattern of femoral head deformity. However, when the piglets had grown to 20 weeks old or more—that is, to full skeletal maturity—the femoral head and acetabulum showed severe deformities that were most likely caused by heavy body weight. ▪

Why does outer joint motion predominate in bipolar hip prosthesis?Experimental and clinical studies

Background Theoretically, the motion of a bipolar hip prosthesis is most likely to occur at the inner joint if the frictional coefficients are equal at both surfaces. However, many studies have suggested that most motion occurs at the outer joint. Material and methods We performed an analysis of motion in a cadaveric bone model and in 50 patients during fluoroscopic examination, to determine how the motion is distributed between the two joints and what factors contribute to this distribution. Results The motion distributions varied widely between the patients. However, there was a relative preponderance (63–90%) of outer motion in all directions of leg movement in addition to a persistent coexistence of motion at both joints in 44 of 50 patients. This preponderance of outer motion was the result of an early impingement of the acetabular cup and structural differences between the two joints. Interpretation An adjustment of the positive eccentricity and a decrease in the frictional torque of the inner joint as a result of better lubrication and smoothness can be expected to improve the motion distribution, thus reducing the amount of acetabular erosion.