Infection and Instability Increasing the Risk of Patella Baja and Pseudo-Patella Baja after Revision Total Knee Arthroplasty

Background@#Patella baja with patellar tendon shortening due to traumatic or ischemic injury is a widely known complication after primary total knee arthroplasty (TKA). Pseudo-patella baja may arise from the elevation of the joint line after excessive distal femoral resection. The maintenance of original patellar height is important in revision TKA because postoperative patella baja and pseudo-patella baja can cause inferior biomechanical and clinical results. We investigated the incidence and risk factors of patella baja and pseudo-patella baja after revision TKA. @*Methods@#We retrospectively reviewed data for 180 revision TKAs. Patella baja was defined as a truly low-lying patella with an Insall-Salvati ratio (ISR) of < 0.8 and a Blackburne-Peel ratio (BPR) of < 0.54. Pseudo-patella baja was defined as a relatively lowlying patella compared to the joint line within the normal range of ISR and with a BPR of < 0.54. Clinically, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and range of motion (ROM) were evaluated. Risk factors increasing the incidence of patella baja and pseudo-patella baja after revision TKA were evaluated using multiple regression analysis. @*Results@#Before revision TKA, 169 knees did not exhibit patella baja or pseudo-patella baja, while 9 knees showed patella baja and 2 knees exhibited pseudo-patella baja. At 2 years after revision TKAs, 25 knees (13.9%) showed patella baja and 23 knees (12.8%) exhibited pseudo-patella baja. Despite no differences in the postoperative WOMAC score between groups with and without patella baja and pseudo-patella baja, the postoperative ROM was significantly smaller in the group with patella baja (113.3°) or pseudo patella baja (110.5°) than in the normal group (122.0°). Infection as the cause of revision TKA increased the risk of patella baja (odds ratio, 10.958; p < 0.001), and instability increased the risk of pseudo-patella baja (odds ratio, 11.480; p < 0.001). @*Conclusions@#Infection and instability resulted in increases in the incidence of patella baja and pseudo-patella baja after revision TKA. Information about the risk factors of patella baja and pseudo-patella baja will help TKA surgeons plan the height of the patella after revision TKA and improve clinical outcomes.

Comparison of Mechanical Axis and Dynamic Range Assessed with Weight Bearing Radiographs and Navigation System in Closed Wedge High Tibial Osteotomy

PURPOSE: To compare navigation and weight bearing radiographic measurements of mechanical axis (MA) before and after closed wedge high tibial osteotomy (HTO) and to evaluate post-osteotomy changes in MA assessed during application of external varus or valgus force. MATERIALS AND METHODS: Data from 30 consecutive patients (30 knees) who underwent computer-assisted closed-wedge HTO were prospectively analyzed. Pre- and postoperative weight bearing radiographic evaluation of MA was performed. Under navigation guidance, pre- and post-osteotomy MA values were measured in an unloaded position. Any change in the post-osteotomy MA in response to external varus or valgus force, which was named as dynamic range, was evaluated with the navigation system. The navigation and weight bearing radiographic measurements were compared. RESULTS: Although there was a positive correlation between navigation and radiographic measurements, the reliability of navigation measurements of coronal alignment was reduced after osteotomy and wedge closing. The mean post-osteotomy MA value measured with the navigation was 3.5°±0.8° valgus in an unloaded position. It was 1.3°±0.8° valgus under varus force and 5.8°±1.1° valgus under valgus force. The average dynamic range was >±2°. CONCLUSIONS: Potential differences between the postoperative MAs assessed by weight bearing radiographs and the navigation system in unloaded position should be considered during computer-assisted closed wedge HTO. Care should be taken to keep the dynamic range within the permissible range of alignment goal in HTO.

Protective Effect of Etomidate on Kainic Acid-induced Neurotoxicity in Rat Hippocampus / 대한마취과학회지

BACKGROUND: The present investigation was undertaken to evaluate the neuroprotective effect of etomidate against kainic acid (KA) induced neurotoxicity in rats by using the immunoreactivity of heat shock protein-70 (HSP-70) and the acid-fuchsin stain. METHODS: Administration of etomidate (20 mg/kg, I.P.) was performed in sequence; first being just one hour after a KA (10 mg/kg, I.P.) injection, then three more times at one hour intervals. Neuronal damages in the hippocampus were evaluated by using the acid-fuchsin stain to detect cell death and HSP-70 induction as an index of cell injury at 24 h after the administration of KA. RESULTS: HSP-70 induction and acid fuchsin positive neurons were increased in the CA1 and CA3 regions of the hippocampus after a KA injection but significantly decreased by an injection of etomidate (P < 0.01). CONCLUSIONS: These results suggest that the etomidate has a potential effect on the protection of neurons against KA-induced neurotoxicity.

The Role of Growth Factors to Rabbit Chondrocytes and Subtypes of Collagen in Three Dimensional High Density Culture

Cartilage is commonly used autogenous material for aesthetic and reconstructive surgery and major donor sites of cartilage are ear, nasal septum, and rib. As the cartilage correlates with ossification and can be used for joint reconstruction. Many growth factors influencing growth and differentiation of chondrocytes have been reported, and matrix composition produced by chondrocytes may vary in types and quantity according to culture duration. Initially the chondrocytes in culture aggregate, then secrete type I collagen. Type II collagen is produced during differentiation process, and synthesis of type X collagen is the last step. In this study, chondrocytes were isolated from ear cartilage of the New Zealand white rabbit weighing 400 gm. We performed high density culture using penicylinder and pellet method. The cells were polygonal in morphology and viable under the inverted microscope. This experiment was designed to evaluate the effect of IGF-I, TGF- p, and b- FGF on the synthesis of collagen in chondrocyte culture. Optimal concentration of growth factors was determined using H-thymidine incorporation into DNA. After the addition of optimal concentration of each growth factors in experimental groups, the uptake of H-proline was measured. Only IGF-I showed a statistically significant increase of collagen synthesis. We observed how subtypes of collagen were influenced by growth factors in two culture methods and by differing the addition timing of growth factors. SDS-PAGE was adopted for subtyping of collagen. All subtypes of collagen were found in both culture methods and all growth factors facilitated the production of type II and type X collagen and may be devoted to the differentiation of chondrocytes. Immunohistochemical staining for type I, and type II collagen was examined to confirm the above result. In pellet culture, type II collagen was stained densely in response to the addition of three kinds of growth factors. The results of penicylinder culture showed similar outcome to those from pellet cultured group. From the above results, we concluded as follows; First, IGF-I generally influence the synthesis of type I and II collagen. Second, TGF beta increased the synthesis of collagen. Third, b-FGF increased the synthesis of type II and type X collagen. We concluded that IFG-I is the only growth factor which is effective regardless of culture duration and method. TGF- beta and b-FGF, which are potent mitogen, facilitate the secretion of collagen.

The Effect of IGF-I on Collagen Synthesis in Cultured Chondrocytes

Cartilage is one of the most commonly manipulated tissue in esthetic and reconstructive surgery. Cartilage has an important role in longitudinal bone growth. Anabolic hormones and locally produced peptide growth factors are known to influence this process Matrix composition changes through proliferation, maturation, and differentiation of chondrocytes, and endochondral ossification thereafter. Defined cartilage matrix is synthesized during the maturation of chondrocytes where the major change is the increment of type II collagen. Variable sulfated mucololysaccharides and hyaluronic acid are also synthesized during this maturation. IGF-I(insulin like growth factor-I), so called somatomedin C, is a prominent growth factor in serum. IGF-I is known to be involved in long growth. IGF-I is affected by pituitary growth hormone. There are few studies done on IGF-I effect in cartilage matrix formation and possible changes of collagen subtypes. This experiment was designed to see the IGF-I effect on the colagen synthesis of cultured chondrocytes. Optimal concentration of IGF-I for the experiment was determined using H3-thymidine incorporation into DNA. The IGF-I effect on collagen synthesis was studied using H3-proline. The IGF-I effect on the synthesis of subtypes of collagen was studied using SDS-PAGE and immunocytochemical staining. Chondrocytes were isolated from the ears of New Zealand white rabbit and cultured in 2 X 10(5) cells/300 microgram density. IGF-I increased DNA synthesis, and optimal concentration of IGF-I was determined by dose-relationship curve as 10ng/ml. Collagen synthesis was increased by IGF-I. Type II collagen was increased on SDS-PAGE with IGF-I and this gel electrophoresis showed type X collagen, also. The increase in type II collagen was confirmed with immunocytochemical staining, the reaction becoming stronger with the addition of IGF-I. Type I collagen was not changed with IGF-I on immunocytochemistry. We conclude that IGE-I is an important modulator influencing not only proliferation and maturation but also terminal different-iation of chondrocytes.

Prognostic significance of mastoid pneumatization in childhood otitis media with effusion: temporal bone CT evaluation / 대한이비인후과학회지

No abstract available.