The Influence of Knee Flexion Angle for Graft Fixation on Rotational Knee Stability During Anterior Cruciate Ligament Reconstruction: A Biomechanical Study.

PURPOSE: To evaluate the effect of knee flexion angle for hamstring graft fixation, full extension (FE), or 30°, on acceleration of the knee motion during pivot-shift testing after either anatomic or nonanatomic anterior cruciate ligament (ACL) reconstruction using triaxial accelerometry. METHODS: Two types of ACL reconstructions (anatomic and nonanatomic) using 2 different angles of knee flexion during graft fixation (FE and 30°) were performed on 12 fresh-frozen human knees making 4 groups: anatomic-FE, anatomic-30°, nonanatomic-FE, and nonanatomic-30°. Manual pivot-shift testing was performed at ACL-intact, ACL-deficient, and ACL-reconstructed conditions. Three-dimensional acceleration of knee motion was recorded using a triaxial accelerometer. RESULTS: The anatomic-30° group showed the smallest overall magnitude of acceleration among the ACL-reconstructed groups (P = .0039). There were no significant differences among the anatomic-FE group, the nonanatomic-FE group, and the nonantomic-30° group (anatomic-FE vs nonanatomic-FE, P = .1093; anatomic-FE vs nonanatomic-30°, P = .8728; and nonanatomic-FE vs nonanatomic-30°, P = .1093). After ACL transection, acceleration was reduced by ACL reconstruction with the exception of the nonanatomic-FE group that did not show a significant difference when compared with the ACL-deficient (P = .4537). CONCLUSIONS: The anatomic ACL reconstruction with the graft fixed at 30° of knee flexion better restored rotational knee stability compared with FE. An ACL graft fixed with the knee at FE in anatomic position did not show a significant difference compared with the nonanatomic ACL reconstructions. CLINICAL RELEVANCE: Knee flexion angle at the time of graft fixation for ACL reconstruction can be considered to maximize the rotational knee stability.

The effect of tunnel placement on rotational stability after ACL reconstruction: evaluation with use of triaxial accelerometry in a porcine model.

PURPOSE: Conventional transtibial technique fails to restore the rotational knee stability in spite of successful anterior laxity, while anatomic anterior cruciate ligament reconstruction using the anteromedial portal technique has been developed expecting better rotational kinematics because of closer reproduction of the native anterior cruciate ligament anatomy. However, the rotational instability after those two procedures has not been fully examined especially in terms of dynamic component of the rotational stability. The purpose was to assess the effect of anatomic versus non-anatomic tunnel placement on rotational knee stability after anterior cruciate ligament reconstruction using triaxial accelerometry. METHODS: Sixteen porcine knees underwent a manual pivot-shift test at four different conditions: (1) anterior cruciate ligament intact, (2) anterior cruciate ligament deficient, (3) non-anatomic transtibial reconstruction, and (4) anatomic anteromedial portal reconstruction. The three-dimensional acceleration of knee motion during the pivot-shift test was recorded using a triaxial accelerometer. RESULTS: Both anterior cruciate ligament reconstructions decreased significantly the acceleration of the pivot-shift test from the increased level in the anterior cruciate ligament-deficient condition. However, the transtibial technique fails to reach the intact level of acceleration, while the anteromedial portal technique reduced the acceleration to even less than the intact level. CONCLUSION: The transtibial anterior cruciate ligament reconstruction could not restore the dynamic rotational stability of the intact knee, whereas the anteromedial portal technique restored the dynamic rotational stability closer to the intact level. LEVEL OF EVIDENCE: III.

Is the Rotatory Knee Stability Immediately Decreased Following a Competitive Soccer Match?

Fatigue induced by soccer playing increases physical efforts, which might alter the transverse knee stability, a known factor that promotes knee injuries, particularly anterior cruciate ligament injury. Thereby, primarily, we aimed to determine whether rotatory knee stability decreases immediately following a competitive soccer match in amateur players. Furthermore, we assessed the role of the preferred and non-preferred limbs to kick a ball in rotatory knee stability and the correlation between performance parameters and rotatory knee stability. We hypothesized that the knee stability decreases immediately after a competitive soccer match in amateur players. Eight healthy amateur soccer players (aged 27.2 ± 4.7 years and with body mass index of 23.8 ± 1.2 kg m-2) were included immediately before and after a competitive soccer match. The rotatory knee stability was assessed in the preferred and non-preferred limbs through the acceleration and jerk of the pivot shift maneuver and by the internal knee rotation of a pivoting landing task. Two-way repeated-measures ANOVA for factors time (before and after the soccer match) and limb (preferred and non-preferred) and multiple comparisons were performed using α = 5%. There was a statistical significance for the main factor time in the acceleration (5.04 vs. 6.90 ms-2, Δ = 1.86 ms-2, p = 0.020, η2 = 0.331) and jerk (18.46 vs. 32.10 ms-2, Δ = 13.64 ms-2, p = 0.004, η2 = 0.456) of the pivot shift maneuver. Rotatory stability decreases following a competitive soccer match in amateur soccer players under fatigue. Both the acceleration and jerk during the pivot shift maneuver is increased without significant internal knee rotation changes during the pivoting landing task.

Evaluation of rotational instability in the anterior cruciate ligament deficient knee using triaxial accelerometer: a biomechanical model in porcine knees.

PURPOSE: To measure the acceleration in multiple directions of the rotational instability in ACL deficient models using porcine knees. METHODS: Ten porcine knees were tested with ACL intact and tear models. The pivot shift test was performed manually, and the acceleration of the pivot shift phenomenon was recorded by the use of a triaxial accelerometer. Tests were repeated in four different ACL states: (1) intact; (2) partial AM deficient; (3) complete AM deficient, and (4) complete ACL (AM and PL) deficient. The acceleration in three directions and the magnitude of acceleration were measured to evaluate rotational instability and compare between different ACL conditions. RESULTS: Significantly increased accelerations were observed in the complete deficient ACL model, while the partial ACL tear models demonstrated a slight increase without statistical significance. The accelerometer detected stepwise increases in the acceleration with the extent of ACL tear. Additionally, the PL bundle exhibited the largest contribution for rotational instability (80.4%) when compared with the AM (19.5%) bundles. CONCLUSION: Triaxial accelerometer could serve as a quantitative evaluation of rotational instability. The present study demonstrated that PL bundle has the most important contribution for rotational instability (80.4%) when compared to IM bundle (0.01%) and AM bundle (19.5%) in porcine knee model.

Biomechanical comparison of three anatomic ACL reconstructions in a porcine model.

PURPOSE: Different tunnel configurations have been used for double-bundle (DB) anterior cruciate ligament (ACL) reconstruction. However, controversy still exists as to whether three-tunnel DB with double-femoral tunnels and single-tibial tunnel (2F-1T) or with single-femoral tunnel and double-tibial tunnels (1F-2T) better restores intact knee biomechanics than single-bundle (SB) ACL reconstruction. The purpose was to compare the knee kinematics and in situ force in the grafts among SB and two types of three-tunnel DB ACL reconstructions performed in an anatomic fashion. METHODS: Twenty-four porcine knees were subjected to an 89-N anterior tibial load (simulated KT-1000 test) at 30°, 60°, and 90° of flexion and to a 4-Nm internal tibial torque and 7-Nm valgus torque (simulated pivot-shift test) at 30° and 60° of flexion. The resulting knee kinematics and in situ force in the ACL or replacement grafts were measured using a robotic system for (1) ACL-intact, (2) ACL-deficient, and (3) three ACL reconstructed knees: SB; DB 2F-1T; and DB 1F-2T. RESULTS: During the simulated pivot-shift test, the DB grafts more closely restored the in situ force in the intact ACL at low flexion angle than the SB graft. There were no significant differences in knee kinematics between SB and DB ACL reconstruction. The DB 2F-1T reconstruction did not show a significant difference in knee kinematics or in situ force when compared to the DB 1F-2T technique. CONCLUSION: The in situ force in the ACL is better restored with an anatomic three-tunnel DB reconstruction in response to the simulated pivot-shift test at low flexion angle when compared to an anatomic SB reconstruction. Both three-tunnel DB ACL reconstructions performed in an anatomic fashion had similar biomechanical behavior. As long as it is performed anatomically, DB ACL reconstruction could be better alternative than SB ACL reconstruction, no matter which three-tunnel procedure, 2F-1T or 1F-2T, is used.

Laparoscopic surgical treatment for patients with short- and long-segment Barrett's esophagus: which technique in which patient?

Laparoscopic antireflux surgery is very successful in patients with short-segment Barrett's esophagus (BE), but in patients with long-segment BE, the results remain in discussion. In these patients, during the open era of surgery, we performed acid suppression + duodenal diversion procedures added to the antireflux procedure (fundoplication + vagotomy + antrectomy + Roux-en-Y gastrojejunostomy) to obtain better results at long-term follow-up. The aim of this prospective study is to present the results of 3 to 5 years' follow-up in patients with short-segment and long-segment or complicated BE (ulcer or stricture) who underwent fundoplication or the acid suppression-duodenal diversion technique, both performed by a laparoscopic approach. One hundred eight patients with histologically confirmed BE were included: 58 patients with short-segment BE, and 50 with long-segment BE, 28 of whom had complications associated with severe erosive esophagitis, ulcer, or stricture. After surgery, among patients treated with fundoplication with cardia calibration, endoscopic erosive esophagitis was observed in 6.9% of patients with short-segment BE, while 50% of patients with long-segment BE presented with positive acid reflux, persistence of endoscopic esophagitis with intestinal metaplasia, and progression to dysplasia (in 5% of cases; P = 0.000). On the contrary, after acid suppression-duodenal diversion surgery in patients with long-segment BE, more than 95.6% presented with successful results regarding recurrent symptoms and endoscopic regression of esophagitis. Regression of intestinal metaplasia to the cardiac mucosa was observed in 56.9% of patients with short-segment BE who underwent fundoplication and in 61% of those with long-segment BE treated with the acid suppression-duodenal diversion procedure. Patients with long-segment BE who experienced fundoplication alone presented no regression of intestinal metaplasia; on the contrary, progression to dysplasia was observed in 1 case (P = 0.049). Patients with short-segment BE can be successfully treated with fundoplication, but for patients with long-segment BE, we suggest performance of fundoplication plus an acid suppression-duodenal diversion procedure.

Laparoscopic sleeve gastrectomy: surgical technique, indications and clinical results.

BACKGROUND: Laparoscopic sleeve gastrectomy (LSG) has been introduced as a multipurpose restrictive procedure for obese patients. Variations of the surgical technique may be important for the late results. METHODS: 50 patients submitted to LSG from January 2005 to December 2006 were studied. Mean age was 38.2 years, preoperative weight was 103.4 +/- 14.1 kg (78 to 146 kg), and preoperative BMI was 37.9 +/- 3.4 (32.9 to 46.8). Important co-morbidities were present in 39 patients (78%). RESULTS: Operative time was 110 +/- 15 min. Intraoperative difficulties were observed in 7 patients. Volume of the resected specimen was 760 +/- 55 ml and capacity of the gastric remnant was 108.5 +/- 25 ml. There was no conversion to open surgery. Histology of the resected stomach was normal in 8 patients, while chronic gastritis was found in 42 patients. At 6 and 12 months postoperatively, weight loss was 28.0 +/- 6.4 kg and 32.6 +/- 6.8 kg respectively. In the 18 patients who have reached 1 year follow-up, % excess BMI loss reached 85 +/- 0.7%. Most of the medical diseases associated with the obesity resolved after 6 to 12 months. CONCLUSION: LSG may be an acceptable operation. It is easy to perform, safe, and has a lower complication rate than other bariatric operations. Further studies are necessary for the clinical results at long-term follow-up.

Laparoscopic anterior cardiomyotomy plus anterior Dor fundoplication without division of lateral and posterior periesophageal anatomic structures for treatment of achalasia of the esophagus.

Laparoscopic cardiomyotomy is the treatment of choice for patients with achalasia of the esophagus. Several different techniques and modifications have been reported concerning the approach (thoracoscopic or laparoscopic), type and length of the myotomy, with or without fundoplication, type of fundoplication, etc. In this prospective study, we report our simplified technique for anterior cardiomyotomy with Dor fundoplication and the results obtained using this procedure. Only the anterior wall of the esophagus was exposed without dissection of the lateral or posterior periesophageal anatomic structures for the technique. Twenty-five patients were operated by a single surgeon. The diagnosis was based on the clinical, radiologic, endoscopic, and functional esophageal tests. Achalasia was classified into 3 types: achalasia type I was diagnosed in 5 patients, type II in 6 patients, and type III in 14 patients. Manometry demonstrated a mean resting pressure of 33.5 mm Hg (range, 18 to 55), associated with incomplete relaxation. The hospital stay was 3 days; the median operative time was 115 minutes (range, 90 to 150), 2 small mucosal perforations occurred which were immediately sutured during surgery without conversion into open technique and no postoperative complications occurred. After operation, lower esophageal sphincter pressure returned to normal values and complete relaxation in all patients. In type II and III achalasia, the esophageal body diameter decreased more than 50% (P=0.001) compared with the preoperative diameter, and the internal diameter of the esophagogastric junction increased significantly (P=0.001). Only 2 patients presented occasional heartburn and 2 patients received 1 session of hydrostatic dilatation due to mild residual dysphagia. No late recurrence of dysphagia has been observed to the present time (1 to 5 y of follow-up). In conclusion, the goals of the surgery for achalasia are obtained with this simplified technique.

Anatomical deformities after laparoscopic antireflux surgery.

Laparoscopic Nissen, Nissen-Rossetti, cardial calibration with gastropexy, and other modifications are the procedures commonly used for surgical treatment of gastroesophageal reflux disease. Postoperative failures have been reported ranging from 10% to 15% associated with postoperative symptoms or recurrent gastroesophageal reflux. In this paper, we present 38 patients submitted to different procedures in which different "abnormal" deformities were found during the postoperative radiological evaluation with barium swallow. The symptoms associated with these deformities were pain (62%), dysphagia (43%), early satiety (37%), postprandial discomfort (35%), and recurrent postoperative reflux (30%). Dysphagia and pain were frequently observed after the Nissen-Rossetti technique, in which a bilobed stomach and stricture (46%) were confirmed. Hiatal hernia was observed in two patients, and slipped Nissen in one patient associated to pain and early satiety. Patients were submitted to conservative treatment (endoscopic dilatation, proton pump inhibitors, and prokinetics), but 10 patients were submitted to redo surgery. There were no complications, and good results were obtained after redo operations.

Radiologic and endoscopic characteristics of laparoscopic antireflux wrap: correlation with outcome.

After antireflux surgery for gastroesophageal reflux disease, 10% to 15% of patients may have unsuccessful results as a result of abnormal restoration of the esophagogastric junction. The purpose of this study was to evaluate the postoperative endoscopic and radiologic characteristics of the antireflux barrier and their correlation with the postoperative results. After surgery, endoscopic and radiologic features of the antireflux wrap were evaluated in 120 consecutive patients. Jobe's classification of the postoperative valve was used for the definition of a "normal" or "defective" wrap. Patients were evaluated 3 to 5 years later in order to determine the clinical and objective failed fundoplication. A "normal" antireflux wrap was associated with successful results in 81.7% of the patients. On the contrary, defective radiologic or endoscopic antireflux wrap was observed in 19% of cases. Among these patients, hypotensive lower esophageal sphincter was observed in 50% to 65% of patients, abnormal 24-hour pH monitoring in 91%, and recurrent postoperative erosive esophagitis in 50% of patients, respectively (P < 0.001). "Defective" antireflux fundoplication is associated with recurrent reflux symptoms, presence of endoscopic esophagitis, hypotensive lower esophageal sphincter, and abnormal acid reflux.

Myotube depolarization generates reactive oxygen species through NAD(P)H oxidase; ROS-elicited Ca2+ stimulates ERK, CREB, early genes.

Controlled generation of reactive oxygen species (ROS) may contribute to physiological intracellular signaling events. We determined ROS generation in primary cultures of rat skeletal muscle after field stimulation (400 1-ms pulses at a frequency of 45 Hz) or after depolarization with 65 mM K+ for 1 min. Both protocols induced a long lasting increase in dichlorofluorescein fluorescence used as ROS indicator. Addition of diphenyleneiodonium (DPI), an inhibitor of NAD(P)H oxidase, PEG-catalase, a ROS scavenger, or nifedipine, an inhibitor of the skeletal muscle voltage sensor, significantly reduced this increase. Myotubes contained both the p47phox and gp91phox phagocytic NAD(P)H oxidase subunits, as revealed by immunodetection. To study the effects of ROS, myotubes were exposed to hydrogen peroxide (H2O2) at concentrations (100-200 microM) that did not alter cell viability; H2O2 induced a transient intracellular Ca2+ rise, measured as fluo-3 fluorescence. Minutes after Ca2+ signal initiation, an increase in ERK1/2 and CREB phosphorylation and of mRNA for the early genes c-fos and c-jun was detected. Inhibition of ryanodine receptor (RyR) decreased all effects induced by H2O2 and NAD(P)H oxidase inhibitors DPI and apocynin decreased ryanodine-sensitive calcium signals. Activity-dependent ROS generation is likely to be involved in regulation of calcium-controlled intracellular signaling pathways in muscle cells.

Laparoscopic cardial calibration and gastropexy for treatment of patients with reflux esophagitis: pathophysiological basis and result.

Laparoscopic antireflux surgery is the gold standard procedure for treatment of patients with reflux esophagitis. The current results of the laparoscopic approach are absolutely comparables with the results obtained during the open surgery era. The Nissen, Nissen-Rossetti, or Toupet techniques are the more frequently used. We have performed cardial calibration and posterior gastropexy or Nissen fundoplication by the open approach with similar results. The purpose of this article is to present the anatomo-physiological basis for employing cardial calibration and posterior gastropexy in patients with reflux esophagitis. This study includes 108 symptomatic patients, 12 of them with associated extraesophageal manifestations ( posterior laryngitis). Endoscopic mild or moderate esophagitis was confirmed in 83 patients, Barrett's esophagus in 12 patients, and type I or II hiatal hernia in 13 patients. All patients were also submitted to manometry, 24 hour intraesophageal pH monitoring, and barium swallow before and after surgery. Follow-up ranged from 12 to 36 months. There were no conversion, major intraoperative, or postoperative complications; nor were there any deaths. Postoperative dysphagia was present in 5% of cases. Symptomatic recurrence of reflux was observed in 10.3% and endoscopic presence of esophagitis in 12.3% of cases . Lower esophageal sphincter pressure increased significantly after surgery, even in patients with endoscopic recurrence. 24-hour intraesophageal monitoring improved after surgery, except in patients with objective recurrence of esophagitis. In conclusion, laparoscopic cardial calibration with posterior gastropexy presents comparable results to those reported after Nissen fundoplication and therefore could be another excellent therapeutic option in patients with reflux esophagitis.

[Prader-Willi Syndrome (PWS) associated to morbid obesity: surgical treatment]. / Síndrome Prader-Willi asociado a obesidad mórbida: tratamiento quirúrgico.

Prader-Willi Syndrome (PWS) is a multisystemic genetic disease characterized by hypothalamic hypogonadism, mental retardation and compulsive hyperphagia associated with early and severe obesity. Complications of overweight, such as type-2 diabetes Mellitus, dyslipidemia and diffuse atheromatosis are common. We report a 15 years old morbid obese male with PWS, with a body mass index of 57.7 kg/m2, refractory to weight-lowering treatments. He underwent preoperative evaluation and treatment by a multidisciplinary team, and subjected to a 95% gastrectomy, leaving a 50 ml remnant pouch and a long limb (120 cm) Y-Roux gastro-jejuno anastomosis. There were no surgical complications, oral feeding was initiated at the 5th day with an hypocaloric diet. During the first postoperative year, the patient lost 70 kg, achieving a body mass index of 30 kg/m2. Surgical treatment can become a therapeutic choice for obesity in PWS patients.

Estudio prospectivo y randomizado de 2 tipos de anastomosis como método de reconstrucción después de gastrectomía total / Randomized and prospective study of 2 types of anastomosis as reconstruction method after total gastrectomy

Se realizó un estudio prospectivo y randomizado comparando los resultados inmediatos de 2 tipos de anastomosis después de gastrectomía total por cáncer gástrico. Hubo 37 pacientes seleccionados para una anastomosis esofagoyeyunal terminolateral simple y 43 pacientes para una anastomosis tipo Tomoda. No se observó diferencias significativas en ambos grupos en cuanto a características epidemiológicas. La duración de la operación, las complicaciones sépticas postoperatorias y la incidencia de fístulas anastomóticas fueron similares en ambos grupos al igual que la estadía postoperatoria. Falta evaluar los resultados a largo plazo para comprobar si hay diferencias entre ambas anastomosis