Seung Yup Lee

Rab3a promotes brain tumor initiation and progression.

The Rab protein family is composed of small GTP-binding proteins involved in intracellular vesicle trafficking. In particular, Rab3a which is one of four Rab3 proteins (a, b, c, and d isoforms) is associated with synaptic vesicle trafficking in normal brain. However, despite the elevated level of Rab3a in tumors, its role remains unclear. Here we report a tumorigenic role of Rab3a in brain tumors. Elevated level of Rab3a expression in human was confirmed in both glioma cell lines and glioblastoma multiforme patient specimens. Ectopic Rab3a expression in glioma cell lines and primary astrocytes promoted cell proliferation by increasing cyclin D1 expression, induced resistance to anti-cancer drug and irradiation, and accelerated foci formation in soft agar and tumor formation in nude mice. The overexpression of Rab3a augmented the tumorsphere-forming ability of glioma cells and p53−/− astrocytes and increased expression levels of various stem cell markers. Taken together, our results indicate that Rab3a is a novel oncogene involved in glioma initiation and progression.

The parameters affecting the success of irrigation and debridement with component retention in the treatment of acutely infected total knee arthroplasty.

Background The aims of our study were to evaluate the success rate of irrigation and debridement with component retention (IDCR) for acutely infected total knee arthroplasty (TKA) (< 4 weeks of symptom duration) and to analyze the factors affecting prognosis of IDCR. Methods We retrospectively reviewed 28 knees treated by IDCR for acutely infected TKA from 2003 to 2012. We evaluated the success rate of IDCR. All variables were compared between the success and failure groups. Multivariable logistic regression analysis was also used to examine the relative contribution of these parameters to the success of IDCR. Results Seventeen knees (60.7%) were successfully treated. Between the success and failure groups, there were significant differences in the time from primary TKA to IDCR (p = 0.021), the preoperative erythrocyte sedimentation rate (ESR; p = 0.021), microorganism (p = 0.006), and polyethylene liner exchange (p = 0.017). Multivariable logistic regression analysis of parameters affecting the success of IDCR demonstrated that preoperative ESR (odds ratio [OR], 1.02; p = 0.041), microorganism (OR, 12.4; p = 0.006), and polyethylene liner exchange (OR, 0.07; p = 0.021) were significant parameters. Conclusions The results show that 60.7% of the cases were successfully treated by IDCR for acutely infected TKA. The preoperative ESR, microorganism, and polyethylene liner exchange were factors that affected the success of IDCR in acutely infected TKA.

Effect of Leukocyte-Rich and Platelet-Rich Plasma on Healing of a Horizontal Medial Meniscus Tear in a Rabbit Model

There are limited reports on the effect of platelet-rich plasma (PRP) on meniscus healing. The purpose of this study was to investigate the effect of leukocyte-rich PRP (L-PRP) on potential healing of the horizontal medial meniscus tears in a rabbit model. A horizontal medial meniscus tear was created in both knees of nine skeletally mature adult rabbits. Left or right knees were randomly assigned to a L-PRP group, or a control group. 0.5u2009mL of L-PRP from 10u2009mL of each rabbits whole blood was prepared and injected into the horizontal tears in a L-PRP group. None was applied to the horizontal tears in a control group. The histological assessment of meniscus healing was performed at two, four, and six weeks after surgery. We found that there were no significant differences of quantitative histologic scoring between two groups at 2, 4, and 6 weeks after surgery (p > 0.05). This study failed to show the positive effect of single injection of L-PRP on enhancing healing of the horizontal medial meniscus tears in a rabbit model. Single injection of L-PRP into horizontal meniscus tears may not effectively enhance healing of horizontal medial meniscus tears.

An in Vivo 3D Computed Tomographic Analysis of Femoral Tunnel Geometry and Aperture Morphology Between Rigid and Flexible Systems in Double-Bundle Anterior Cruciate Ligament Reconstruction Using the Transportal Technique

PURPOSEnThe aim of this study was to compare femoral tunnel length, femoral graft-bending angle, posterior wall breakage, and femoral aperture morphologic characteristics between rigid and flexible systems after double-bundle (DB) anterior cruciate ligament (ACL) reconstruction using the transportal (TP) technique.nnnMETHODSnWe evaluated 3-dimensional computed tomography (3D-CT) results for 54 patients who underwent DB ACL reconstruction using the TP technique with either a flexible system (nxa0= 27) or a rigid system (nxa0= 27). The femoral tunnel length, femoral graft-bending angle, posterior wall breakage, femoral tunnel aperture height to width (H:W) ratio, aperture axis angle, and femoral tunnel position were assessed using OsiriX Imaging Software and Geomagic Qualify 2012 (Geomagic, Cary, NC).nnnRESULTSnThe mean anteromedial (AM) femoral tunnel length of the flexible group was significantly longer than that of the rigid group (Pxa0= .009). The mean femoral graft-bending angles in the flexible group were significantly less acute than those in the rigid group (AM, P < .001; posterolateral [PL], Pxa0= .003]. Posterior wall breakage was observed in both groups (Pxa0= 1.00). The mean H:W ratios in the rigid group were significantly larger (more elliptical) than those of the flexible group (AM, P < .001; PL, Pxa0= .006). The mean aperture axis angle of the PL femoral tunnel in the rigid group was more parallel to the femoral shaft axis than that in the flexible group (P < .001). There were no significant differences in femoral tunnel position between the 2 groups.nnnCONCLUSIONSnThe AM femoral tunnel length and the AM/PL femoral graft-bending angle of the flexible system were significantly longer and less acute than those of the rigid system. However, the aperture morphologic characteristics of the AM/PL femoral tunnel and the aperture axis angle of the PL femoral tunnel in the rigid system were significantly more elliptical and closer to parallel to the femoral shaft axis than those of the flexible system.nnnLEVEL OF EVIDENCEnLevel III, retrospective comparative study.

Sagittal osteotomy inclination in medial open-wedge high tibial osteotomy

PurposeUnlike postoperative changes in posterior tibial slope after medial open-wedge high tibial osteotomy, sagittal osteotomy inclination has not been examined. It has been recommended that the osteotomy line in the sagittal plane be parallel to the medial posterior tibial slope. The purpose of this study was to determine the frequency of parallel osteotomy in medial open-wedge high tibial osteotomy.MethodsTo determine the sagittal osteotomy inclination, the angle between the medial joint line and the osteotomy line was measured in the lateral radiograph. A positive angle value indicates that the osteotomy is anteriorly inclined relative to the medial posterior tibial slope. Correlation between the sagittal osteotomy inclination and posterior tibial slope was also evaluated.ResultsThe mean sagittal osteotomy inclination was 15.1xa0±xa07.5°. The majority 87.1xa0% of knees showed an anterior-inclined osteotomy. There was a significantly positive correlation between the postoperative posterior tibial slope and the sagittal osteotomy inclination (r, 0.33; 95xa0% confidence interval (CI) 0.19–0.46; Pxa0<xa00.001). The postoperative change in posterior tibial slope also showed a significantly positive correlation with the sagittal osteotomy inclination (r, 0.35; 95xa0% CI 0.21–0.47; Pxa0<xa00.001).ConclusionAlthough parallel osteotomy in the sagittal plane relative to the medial joint line was planned, only 12.9xa0% of cases achieved osteotomy parallel to the medial posterior tibial slope in the sagittal plane. Because of high rate of the anterior-inclined osteotomy and their correlations with posterior tibial slope, surgeons should make all efforts to perform parallel osteotomy relative to medial posterior tibial slope.Level of evidenceIV

Patient-reported outcomes correlate with functional scores after opening-wedge high tibial osteotomy: a clinical study

AbstractPurposeThe purpose of this study was to assess post-operative patient subjective satisfaction and to analyze associated peri-operative factors following biplanar medial open wedge high tibial osteotomy (OWHTO).MethodsThe study cohort consisted of 88 patients with a minimum of two years of follow-up. Patient satisfaction was evaluated with a questionnaire that assessed (1) overall satisfaction, (2) pain relief, (3) daily living functions, and (4) cosmesis. Patients were categorized into two groups (satisfied or unsatisfied) based on overall satisfaction questionnaire. Pre- and post-operative objective clinical statuses were assessed with a knee scoring system based on the American Knee Society (AKS), the Western Ontario McMaster University Osteoarthritis Index (WOMAC), and range of motion.ResultsOf the 88 patients, 85.2% were graded as satisfied according to the overall satisfaction estimation. The percentage of patients satisfied with pain relief, daily living functions, and cosmesis were 85.2%, 86.4%, and 86.4%, respectively. Multivariable logistic regression analysis demonstrated that pre-operative Hip-Knee-Ankle angle (HKAA) (odds ratio (OR)xa0=xa01.812), post-operative AKS knee score (ORxa0=xa01.156), and post-operative HKAA (ORxa0=xa00.717) were significantly associated with overall satisfaction. Pre-operative HKAA (ORxa0=xa01.436), post-operative WOMAC activity score (ORxa0=xa00.865), and post-operative HKAA (ORxa0=xa00.505) were significant predictors for satisfaction with pain reduction, daily living functions, and cosmesis, respectively.ConclusionsBiplanar medial OWHTO is an effective treatment for osteoarthritis with varus deformity in terms of subjective satisfactory outcome. Several factors, including pre- and post-operative HKAA, post-operative AKS and WOMAC score, were significant predictors for subjective satisfaction.n Level of evidence: Level III

Tibial component rotation during the unicompartmental knee arthroplasty: is the anterior superior iliac spine an appropriate landmark?

PurposeNo “ideal” landmark for tibial component rotation in medial unicompartmental knee arthroplasty (UKA) has been suggested by a biomechanical and clinical study. The aim of this study was to investigate whether the anterior superior iliac spine (ASIS) could provide a consistent rotational landmark of the tibial component during mobile-bearing medial UKA using computed tomography (CT).MethodsDuring sagittal tibial resection, we utilized the ASIS as a rotational landmark. In 47 knees that underwent postoperative CT scans after medial UKA, the tibial component position was assessed by drawing a line tangential to the lateral wall of the tibial component. Rotation of the tibial component was measured using two reference lines: a line perpendicular to the posterior cortical rim of the tibia (angle α) and Akagi’s line (angle β). Instant bearing position and posterior cruciate ligament (PCL) fossa involvement were also evaluated. External rotation of the tibial component relative to each reference line was considered positive values.ResultsThe mean α and β angles were 8.0°xa0±xa06.1° (range −4.0 to 24.3) and 8.7°xa0±xa04.8° (range 1.9–25.2), respectively. Fourteen knees (29.8xa0%) showed PCL fossa involvement of the tibial resection margin. One bearing showed complete 180° rotation at 2xa0weeks postoperatively.ConclusionDue to the wide variation and inherent difficulty of identifying the ASIS during the operation, it is not recommended for guidance of sagittal tibial resection during medial UKA. In cases of inappropriate tibia component rotation, risk of PE bearing spinning and iatrogenic PCL injury should be reminded after medial UKA.Level of evidenceIV.

What Factors Are Associated With Femoral Component Internal Rotation in TKA Using the Gap Balancing Technique

BackgroundWhen using the gap-balancing technique for TKA, excessive medial release and varus proximal tibial resection can be associated with internal rotation of the femoral component. Previous studies have evaluated the causes of femoral component rotational alignment with a separate factor analysis using unadjusted statistical methods, which might result in treatment effects being attributed to confounding variables.Questions/purposes(1) What pre- and intraoperative factors are associated with internal rotation of the femoral component in TKA using the gap balancing technique? (2) To what degree does femoral component rotation as defined by the navigation system differ from rotation as measured by postoperative CT?MethodsThree hundred seventy-seven knees that underwent computer-assisted primary TKA attributable to degenerative osteoarthritis with varus or mild valgus alignment in which medial soft tissue release was performed, and those with preoperative radiographs including preoperative CT between October 2007 and June 2014 were included in the study. To achieve a balanced mediolateral gap, the structures released during each medial release step were as follows: Step 1, deep medial collateral ligament (MCL); Step 2, superficial MCL (proximal, above the pes anserine tendon) and semimembranosus tendon; and Step 3, the superficial MCL (distal, below the pes anserine tendon). Knees with internal rotation of the femoral component, which was directed by navigation, to achieve a rectangular mediolateral flexion gap were considered cases, and knees without internally rotated femoral components were considered controls. Univariable analysis of the variables (age, sex, BMI, operated side, preoperative hip-knee-ankle angle, preoperative medial proximal tibial angle, preoperative rotation degree of the clinical transepicondylar axis [TEA] relative to the posterior condylar axis [PCA], coronal angle of resected tibia, resection of the posterior cruciate ligament, type of prosthesis, and extent of medial release) of cases and controls was performed, followed by a multivariable logistic regression analysis on those factors where p equals 0.15 or less. For an evaluation of navigation error, 88 knees that underwent postoperative CT were analyzed. Postoperative CT scans were obtained for patients with unexplained pain or stiffness after the operations. Using the paired t-test and Pearson’s correlation analysis, the postoperative TEA–PCA measured with postoperative CT was compared with theoretical TEA–PCA, which was calculated with preoperative TEA–PCA and actual femoral component rotation checked by the navigation system.ResultsAfter controlling for a relevant confounding variable such as postoperative hip-knee-ankle angle, we found that the extent of medial release (Step 1 as reference; Step 2: odds ratio [OR], 5.7, [95% CI, 2.2–15]; Step 3: OR, 22, [95% CI, 7.8–62], p < 0.001) was the only factor we identified that was associated with internal rotation of the femoral component. With the numbers available, we found no difference between the mean theoretical postoperative TEA–PCA and the postoperative TEA–PCA measured using postoperative CT (4.8° ± 2.7º versus 5.0° ± 2.3º; mean difference, 0.2° ± 1.5º; p = 0.160).ConclusionsExtent of medial release was the only factor we identified that was associated with internal rotation of the femoral component in gap-balancing TKA. To avoid internal rotation of the femoral component, we recommend a carefully subdivided medial-releasing technique, especially for the superficial MCL because once the superficial MCL has been completely released it cannot easily be restored.Level of EvidenceLevel III, therapeutic study.

The Mediolateral Excursion of the Meniscal Bearing during Flexion and Extension of the Knee after Medial Mobile-Bearing Unicompartmental Knee Arthroplasty

&NA; This mediolateral excursion of the bearing during knee motion is supposed to be caused by external rotation of the tibia during knee extension. However, to our knowledge, there is no published clinical evidence supporting these hypotheses. The current study aimed to evaluate the mediolateral excursion of the bearing during flexion‐extension motion of the knee after medial unicompartmental knee arthroplasty (UKA). In 52 knees, varus/valgus (F‐VarVal) or rotational position (F‐Rot) of the femoral component and relative location of the bearing were measured with the standing anteroposterior and modified axial view, respectively. We adopted the modified axial radiographs that are simple to assess the bearing position in the flexed knee. The modified axial view showed excellent inter‐ and intraobserver agreements. F‐Rot in the modified axial view and CT showed a high agreement in terms of validity (r = 0.98; p < 0.0001). On average, the bearing showed more medial position in extension than flexion of the knee. No correlation was found between the femoral component positions (F‐VarVal and F‐Rot) and mediolateral bearing excursion (p = 0.68 and 0.80, respectively). In conclusion, coronal location of bearing according to flexion‐extension of the knee is not influenced by the coronal and axial alignment of the femoral component. With simple radiographic method, more medial position of the bearing according to flexion‐extension of the knee. Our method could be used to assess axial rotation of the femoral component and spin‐out phenomenon of the bearing following the medial UKA.

Pitfalls in Single-Bundle Anterior Cruciate Ligament Reconstruction with the Flexible Reamer System: A Report of Two Cases and Review of the Literature

Case: We present two cases of anterior cruciate ligament reconstruction with use of the flexible reamer system. In both patients, the starting reamers were broken during femoral reaming. The location of the breaks was approximately 60 mm from the tip of the reamer, which is the transitional zone between the proximal and distal portions of the reamer. Conclusion: We believe that several conditions could have resulted in abnormal stress concentration on the flexible reamers, including engagement of the flexible reamer with a physeal scar or the posterior cortex, an inappropriate flexion angle of the knee, and acute bending of the flexible pin.