The effect of meniscal repair on strength deficits 6 months after ACL reconstruction.

INTRODUCTION: Ruptures of the anterior cruciate ligament (ACL) can be accompanied by meniscal lesions. Generally, the rehabilitation protocols are altered by meniscal repair. Therefore, the aim of this study was to investigate the effect of meniscal repair on the early recovery of thigh muscle strength in ACL reconstruction (ACLR). MATERIALS AND METHODS: We performed a matched cohort analysis of n = 122 isolated ACLR (CON) compared to n = 61 ACLR with meniscal repair (ACLR + MR). The subgroups of meniscal repair consisted of 30 patients who had undergone medial meniscus repairs (MM), 19 lateral meniscus repairs (LM) and 12 repairs of medial and lateral meniscus (BM). Isokinetic strength measurement was performed pre-operatively and 6 months post-surgery to perform a cross-sectional and a longitudinal analysis. All injuries were unilateral, and the outcome measures were compared to the non-affected contralateral leg. RESULTS: Six months postoperatively overall there is no significant difference between the groups (extension strength MR 82% vs. CON 85% and flexion strength 86% vs. 88%, resp.). Subgroup analysis showed that medial repairs exhibit a comparable leg symmetry while lateral repairs performed worse with leg symmetry being 76% in extension and 81% in flexion strength. Patients undergoing BM repair performed in between lateral and medial repairs (82% extension, 86% flexion). CONCLUSION: Generally, meniscal repair in conjunction with ACLR does not significantly alter the recovery of limb symmetry in strength at 6 months postoperatively. Interestingly, medial repairs seem to perform superior to lateral meniscal repair and repair of both menisci. Since the recovery of symmetric strength is a major factor in rehabilitation testing, these results will help to advise surgeons on appropriate rehabilitation protocols and setting realistic goals for the injured athlete. LEVEL OF EVIDENCE: III, retrospective cohort study.

Knee and hip joint biomechanics are gender-specific in runners with high running mileage.

Female runners are reported to be more prone to develop specific knee joint injuries than males. It has been suggested that increased frontal plane joint loading might be related to the incidence of these knee injuries in running. The purpose of this study was to evaluate if frontal plane knee and hip joint kinematics and kinetics are gender-specific in runners with high mileage. 3D-kinematics and kinetics were recorded from 16 female and 16 male runners at a speed of 3 m/s, 4 m/s, and 5 m/s. Frontal plane joint angles and joint moments were ascertained and compared between genders among speed conditions. Across all speed conditions, females showed increased hip adduction and reduced knee adduction angles compared to males (p < 0.003). The initial peak in the hip adduction moment was enhanced in females (p = 0.003). Additionally, the hip adduction impulse showed a trend towards an increase in females at slow running speed (p = 0.07). Hip and knee frontal plane joint kinematics are gender-specific. In addition, there are indications that frontal plane joint loading is increased in female runners. Future research should focus on the relationship of these observations regarding overuse running injuries.

Absence of pressure overload induced myocardial hypertrophy after conditional inactivation of Galphaq/Galpha11 in cardiomyocytes.

Myocardial hypertrophy is an adaptational response of the heart to increased work load, but it is also associated with a high risk of cardiac mortality due to its established role in the development of cardiac failure, one of the leading causes of death in developed countries. Multiple growth factors and various downstream signaling pathways involving, for example, ras, gp-130 (ref. 4), JNK/p38 (refs. 5,6) and calcineurin/NFAT/CaM-kinase have been implicated in the hypertrophic response. However, there is evidence that the initial phase in the development of myocardial hypertrophy involves the formation of cardiac para- and/or autocrine factors like endothelin-1, norepinephrine or angiotensin II (refs. 7,8), the receptors of which are coupled to G-proteins of the Gq/11-, G12/13- and Gi/o-families. Cardiomyocyte-specific transgenic overexpression of alpha1-adrenergic or angiotensin (AT1)-receptors as well as of the Gq alpha-subunit, Galphaq, results in myocardial hypertrophy. These data demonstrate that chronic activation of the Gq/G11-family is sufficient to induce myocardial hypertrophy. In order to test whether Gq/G11 mediate the physiological hypertrophy response to pressure overload, we generated a mouse line lacking both Galphaq and Galpha11 in cardiomyocytes. These mice showed no detectable ventricular hypertrophy in response to pressure-overload induced by aortic constriction. The complete lack of a hypertrophic response proves that the Gq/G11-mediated pathway is essential for cardiac hypertrophy induced by pressure overload and makes this signaling process an interesting target for interventions to prevent myocardial hypertrophy.

Relationship between pre- and post-operative isokinetic strength after ACL reconstruction using hamstring autograft.

BACKGROUND: Anterior cruciate ligament (ACL) ruptures are of major concern in sports. As mostly young and active individuals are affected there is an emphasis on the rapid and safe return to sports (RTS). Strengthening the ventral and dorsal thigh muscles is a prerequisite for a successful RTS after ACL reconstruction (ACLR), as persistent muscle weakness may increase the incidence for secondary injuries and impair performance. Aiming to increase evidence on the importance of preoperative muscle strength and the coaching of patients, the purpose of this study is to compare thigh muscle strength pre- and post-operatively after ACLR. METHODS: We performed a retrospective analysis of 80 patients with primary, isolated ACLR using a four-stranded hamstring autograft. We performed bilateral isokinetic concentric strength measurement (60°/s) before and six months after ACLR. Primary outcomes were the maximal knee extension and flexion torque, hamstrings-to-quadriceps ratio (H/Q ratio) and the corresponding limb symmetry indices (LSI). Pearson correlations were calculated for pre- and post-surgical values. RESULTS: The operated as well as the unaffected leg increased maximal knee extension (+ 18% ± 7% p < 0.05; + 11% ± 5% p < 0.05) and flexion torque (+ 9% ± 5% p < 0.05, + 10% ± 6% p < 0.05) throughout the 6 months of rehabilitation. The H/Q ratio remained unaffected (- 2% ± 3% p = 0.93; - 4% ± 4% p = 0.27). LSI of knee extension strength increased significantly (6% ± 3% p < 0.05), while flexion strength remained unaffected (+ 2% ± 4% p = 0.27). Positive correlations underline the interrelationship between the strength pre- and post-surgery for the knee extension (r = 0.788 p < 0.05) and knee flexion strength (r = 0.637 p < 0.05) after ACLR. CONCLUSIONS: Preoperative leg extension and flexion strength normalized to body mass are strongly correlated to postoperative strength performance after ACLR. Therefore, pre-operative quadriceps and hamstring muscle strength deficits may have a significant negative impact on functional performance following ACLR. This emphasizes the need for intensive preoperative screening and subsequent treatment to achieve the best possible preoperative leg strength before ACLR. TRIAL REGISTRATION: DRKS00020210 .

Assessing mechanical ankle instability via functional 3D stress-MRI - A pilot study.

BACKGROUND: Quantitative measurement of the mechanical deficit in chronic ankle instability (CAI) is difficult. Therefore, the distinction between functional (FAI) and mechanical ankle instability (MAI) as well as the evaluation of surgical techniques is difficult. This pilot study uses a novel method of functional 3-dimensional stress ankle-MRI to test its applicability for assessing mechanical ankle instability. METHODS: We used a custom-built ankle arthrometer that allows a stepless positioning of the foot and an axial in situ loading with up to 500 N combined with a 3-dimensional MRI protocol. We assessed four parameters (3D cartilage contact area (CCA) fibulotalar, tibiotalar horizontal and vertical and intermalleolar distance) under six different conditions (neutral-null, plantarflexion-supination and dorsiflexion-pronation each with and without loading) in n = 10 individuals (7 suffering from MAI and 3 healthy controls). FINDINGS: The MAI group showed a substantially increased reduction of lateral osseous constraint compared to healthy controls when the foot was positioned in plantarflexion-supination (CCA fibulotalar 69% vs. 30% in controls). The reduction of the weight bearing surface in plantarflexion-supination was also more pronounced (CCA tibiotalar horizontal -49% in MAI vs. -28% in controls). INTERPRETATION: This novel technique is valuable for assessing mechanical ankle instability in the target population and has a potential clinical benefit for assessing the mechanical deficit of individual patients. Further studies are needed to provide evidence for a possible prognostic value of this novel technique.

Assessment of myocardial perfusion by videodensitometry in the canine model.

Assessment of the functional severity of coronary stenoses has become increasingly important as the intrinsic limitations of coronary angiography have been documented. Videodensitometric coronary flow reserve has been proposed as a means to assess the physiologic significance of a coronary stenosis in humans. This study compared videodensitometric assessment of coronary flow with microsphere quantitation in the closed chest canine model. In five dogs, flow rates were assessed at baseline, after vasodilation with adenosine, after vasoconstriction with vasopressin and during rapid cardiac pacing. The videodensitometric peak density, time to one-half peak density and washout time (time from peak to one-half peak density) were compared at each flow state with flow assessed by microsphere injection. Reproducibility of videodensitometric measurements from two different coronary injections during the same flow state was best with peak density (r = 0.94). Videodensitometric flow ratios (flow state under study to flow at rest) using peak density demonstrated a fair correlation with flow ratios by microsphere (r = 0.81). There was poor correlation between flow ratios when time to one-half peak or washout time was used. Videodensitometric flow measurements used in vivo to assess a wide range of drug-induced coronary flows may not accurately reflect coronary flow measured by microsphere.

Comparison of monoplane and biplane assessment of regional left ventricular wall motion after thrombolytic therapy for acute myocardial infarction.

Regional left ventricular (LV) function was assessed using serial biplane orthogonal LV angiograms recorded before and after reperfusion therapy for acute myocardial infarction (AMI) in 24 patients. Improvement in regional LV function was seen in only 5 patients after reperfusion therapy when only the right anterior oblique view was analyzed; improvement in regional wall motion was seen in 14 when biplane views were analyzed. Biplane analysis was particularly important in the 12 patients with right coronary artery occlusion, among whom the right anterior oblique view showed improvement in only 1 patient but the left anterior oblique view showed improvement in 6 patients (p less than 0.05). Biplane analysis is more sensitive than monoplane right anterior oblique analysis alone for detecting improvement in LV function after reperfusion therapy for AMI. However, both views are complementary, adding information about regional function not revealed by either view alone.

Therapeutic implications of intraoperative pressure measurements after the Fontan operation.

Central venous pressure (CVP) and left atrial pressure (LAP) were monitored continuously for the first 72 hours postoperatively in 32 patients who underwent a Fontan operation in whom preoperative measurements of the pulmonary artery index were available. Integrated mean values were generated for each patient for the following time frames: (1) the first 12 hours after operation, (2) the first 24 hours after operation, (3) postoperative day 2, and (4) postoperative day 3. We found no difference in the CVP, LAP, or transpulmonary gradient, derived as CVP-LAP, measured in the operating room at the completion of the operation versus that measured on the third postoperative day: CVP, 18 +/- 2 mmHg versus 19 +/- 3 mmHg; LAP, 10 +/- 2 mmHg versus 10 +/- 3 mmHg; and transpulmonary gradient, 8 +/- 2 mmHg versus 8 +/- 2 mmHg. The combined incidence of hospital mortality and postoperative takedown associated with the Fontan repair was 12.5%. These findings suggest that a poor hemodynamic result from the Fontan operation can be predicted from intraoperative pressure measurements, because the CVP, LAP, and transpulmonary gradient are unlikely to change significantly in the early postoperative period. Therefore, a decision to take down or fenestrate the repair can reasonably be made in the operating room or the early postoperative period.

Airway pharmacology of the potassium channel opener, HOE 234, in guinea pigs: in vitro and in vivo studies.

The smooth muscle relaxant effects of the novel potassium channel opener, HOE 234, were investigated in guinea pig airways and compared with those of lemakalim (BRL 38227). Both agents evoked concentration-related reduction in spontaneous tracheal tone or in the tone induced by histamine, prostaglandin E2 or carbachol. HOE 234 was more potent, particularly against carbachol, and was considerably longer acting than lemakalim in a wash-out experiment. On testing for preventive efficacy against histamine-induced bronchoconstriction in anaesthetized animals a dose-related decrease of pulmonary resistance (RL) was observed. HOE 234 given either intravenously (i.v.) or by inhalation was longer acting and 3 and 6 times more potent than lemakalim. Administration of 30 micrograms/kg i.v. HOE 234 during continuous bronchoconstriction maintained by infusion of histamine decreased RL for more than 20 min whereas the effect of 100 micrograms/kg i.v. lemakalin disappeared within 4 min. These results show that HOE 234 is effective against contractile response induced by asthma mediators in guinea pig airways and compares favourably with lemakalim. Moreover it acts on acute existing bronchospasm and therefore has the potential to act against asthma attacks.

Computer analysis of orbital fat and muscle volumes in Graves ophthalmopathy.

A technique using special computer programs and data from high-resolution computed tomographic scans has been developed that provides accurate and reproducible volume measurements for muscle and fat in the orbit. Normal values for retrobulbar fat and muscle were established in 19 adults. Nineteen patients with Graves exophthalmopathy were then studied, and a spectrum of change was found that included varying degrees of increased muscle volume or increased volume of both muscle and fat. Further categorization of these changes related to clinical characteristics should lead to a better understanding of the mechanism for ophthalmopathy in Graves disease.

Ophthalmopathy of Graves' disease: computerized volume measurements of the orbital fat and muscle.

Pixel-calibrated volume measurements of muscle and fat in the bony orbit were made from CT scans of 72 patients with Graves' disease, with and without ophthalmopathy, to define characteristic changes present in clinical subgroups. Measurement abnormalities were detected in 87% of Graves' patients with clinically detectable ophthalmopathy and in 70% of hyperthyroid patients without clinical eye signs. Abnormal enlargement of the fat compartment in addition to muscle enlargement was found in 46% of patients with clinical ophthalmopathy; 8% of patients had only increased size of the fat compartment with normal muscle volumes. The ratio of muscle to fat and the volumes of orbital muscle and fat all varied widely in each clinical subgroup. Statistically significant (p less than 0.0001) total muscle-volume increase (range = 3.68-17.06 cm3) and borderline significant (p less than 0.06) fat-compartment increase (range = 6.05-22.63 cm3) were documented in all clinical subgroups. The degree of change of muscle and fat volumes was independent of the clinical group. Abnormal changes were found in the contralateral orbit in six of seven patients who appeared to have unilateral ophthalmopathy on clinical examination. A higher frequency of medial and inferior muscle enlargement was documented in all clinical subgroups.

Superficial temporal-middle cerebral artery bypass: clinical pre- and postoperative angiographic correlation.

Between 1974 and 1982, an anastomosis between a pedicle of the superficial temporal artery (STA) and a cortical branch of the middle cerebral artery (MCA) was performed in 163 carotid systems in 157 patients for internal carotid artery occlusion in whom postoperative angiograms were available for analysis. The angiographic opacification of the arterial system was correlated with the patient's preoperative neurological function and stroke in the follow-up period. From this analysis, the following observations were made: 1) 96% of bypasses were patent; 2) 80% of bypasses achieved a high or medium MCA filling score; 3) there was hypertrophy of the STA in 70% of the cases; 4) greater bypass filling occurred in hemispheres with nonvisualized preoperative collateral circulation than in those with readily visualized collateral flow; 5) a meaningful correlation between angiographically assessed postoperative bypass function and stroke rate was not possible because only four patients suffered an ipsilateral hemispheric stroke in the 8-year follow-up period; and 6) patients who were neurologically unstable before the procedure were at greatest risk for a stroke in the follow-up period. It is apparent that objective analysis of the effectiveness of an STA-MCA bypass, or any other form of extracranial bypass, must await the development of new diagnostic studies in which high-resolution three-dimensional quantification of cerebral blood flow is possible. These studies will necessarily be correlated with preoperative and follow-up clinical data.

Psychological profiles among women with vulvar vestibulitis syndrome: a chart review.

The purpose of this study was to assess the prevalence and type of psychological distress in women with vulvar vestibulitis syndrome (VVS). A retrospective chart review was conducted of all women receiving a diagnosis of VVS referred to a tertiary care facility during a two-year period. Brief psychological questionnaires, including the Personality Assessment Screener, Fear of Negative Evaluation Scale, Golombok-Rust Inventory of Sexual Satisfaction, and the Phobia Rating Scale were administered. Fifty-consecutive cases were reviewed along with 12-15 month follow-up data for 41 cases. Phobic anxiety to vaginal touch or entry was significantly higher in women with VVS than normative data. Fear of Negative Evaluation was a strong associated feature, and for 30% approached clinically significant levels. Twenty-six percent showed a moderate, while another 26% showed a mild clinically distressed profile. Negative affect and social withdrawal were among the most frequently endorsed variables. Improvement in allodynia and intercourse were both related to these psychological variables, and a multiple regression analysis supported the use of psychological instruments in addition to standard medical assessment. A subgroup of women with VVS display clinically significant broad based psychological distress that warrants additional assessment. The use of psychological questionnaires in addition to medical assessment of women with VVS may provide valuable information predictive of treatment needs and response.

Orbital volume measurements in enophthalmos using three-dimensional CT imaging.

The purpose of this study was to investigate enophthalmos by measuring the volume of various orbital structures using off-line computer techniques on images generated by a CT scanner. Eleven patients with enophthalmos had CT scans of the orbits consisting of 30 to 40 adjacent 1.5-mm slices. The data from the scans were analyzed on a Nova 830 stand-alone computer system using software programs that allowed measurement of total bony orbital volume, total soft-tissue volume, globe volume, orbital fat volume, neuromuscular tissue volume, and apex-to-globe distance in the horizontal plane. These data were analyzed comparing the volumes in the normal eye with the volumes in the enophthalmic eye in each patient. The analysis demonstrated a statistically significant increase in bony orbital volume in the enophthalmic eye, but the total soft-tissue volume, fat volume, neuromuscular tissue volume, and globe volume were the same as in the normal eye. The apex-to-globe distance, a measure of the degree of enophthalmos, was less in the enophthalmic eye than in the normal eye. These results suggest that in the majority of patients, the cause of posttraumatic enophthalmos is increased bony orbital volume rather than by soft-tissue loss or fat necrosis. (Several patients showed no volume discrepancies, and it is likely that cicatricial contracture is responsible for the enophthalmos in these cases.) This study suggests that the objective of surgery for correction of enophthalmos in patients with a volume discrepancy should be to decrease the volume of the bony orbit and to increase the anterior projection of the globe.

Comparison of adaptive methods for function estimation from samples.

The problem of estimating an unknown function from a finite number of noisy data points has fundamental importance for many applications. This problem has been studied in statistics, applied mathematics, engineering, artificial intelligence, and, more recently, in the fields of artificial neural networks, fuzzy systems, and genetic optimization. In spite of many papers describing individual methods, very little is known about the comparative predictive (generalization) performance of various methods. We discuss subjective and objective factors contributing to the difficult problem of meaningful comparisons. We also describe a pragmatic framework for comparisons between various methods, and present a detailed comparison study comprising several thousand individual experiments. Our approach to comparisons is biased toward general (nonexpert) users. Our study uses six representative methods described using a common taxonomy. Comparisons performed on artificial data sets provide some insights on applicability of various methods. No single method proved to be the best, since a method's performance depends significantly on the type of the target function, and on the properties of training data.

The dental educator and the law.

Dental educators become vulnerable to student lawsuits if they ignore legislative changes and judicial decisions that affect all academic units in higher education. Issues involving contractual considerations, privacy and grading, and recent copyright revisions are of particular interest to those faculty actively engaged in teaching. Knowledge of these issues as they relate to the course director's daily responsibilities will better prepare the dental educator to avoid litigation and to know when to seek advice of institutional counsel.

[Ankle arthrometry for evaluation of the mechanical component in chronic ankle instability]. / Sprunggelenkarthrometrie zur Diagnostik der mechanischen Komponente der chronischen Sprunggelenkinstabilität.

BACKGROUND: Chronic ankle instability (CAI) is a term that is not well defined until now in spite of a large body of respective literature. Most frequently this umbrella term is used synonymously for functional ankle instability and the role of the mechanical component is not fully understood. PATIENTS/MATERIAL AND METHODS: In a cohort consisting of 15 patients suffering from CAI we preoperatively investigated the mechanical component using both stress radiographs and ankle arthrometry. The functional impact was measured with the FAAM-G (foot and ankle ability measure, German version). The results were compared with a respective group of 17 uninjured subjects. RESULTS: Relevant differences were found between the patients and the uninjured groups in the mechanical (stiffness in the 40 - 60 N region of the load deformation curves and the ratio between stiffness in the 125 - 175 N and 40 - 60 N region) and functional analyses (FAAM-G), respectively (p < 0.001 - 0.040). There was no difference found between groups in the upper (125 - 175 N) region of the load deformation curves. CONCLUSIONS: This article helps to clarify the role of the mechanical component in CAI. Patients suffering from both functional and mechanical ankle instability can be detected with the FAAM-G questionnaire and with different ankle stiffness parameters from ankle arthrometer stress testing. These measures differentiate CAI patients from uninjured persons with functionally and mechanically stable ankles. Therefore, these instruments can be recommended to diagnose and quantify the mechanical component in CAI.

How to sprain your ankle - a biomechanical case report of an inversion trauma.

In order to develop preventive measures against lateral ankle sprains, it is essential to have a detailed understanding of the injury mechanism. Under laboratory experimental conditions the examination of the joint load has to be restricted with clear margins of safety. However, in the present case one athlete sprained his ankle while performing a run-and-cut movement during a biomechanical research experiment. 3D kinematics, kinetics, and muscle activity of the lower limb were recorded and compared to 16 previously performed trials. Motion patterns of global pelvis orientation, hip flexion, and knee flexion in the sprain trail deviated from the reference trials already early in the preparatory phase before ground contact. During ground contact, the ankle was rapidly plantar flexed (up to 1240°/s), inverted (up to 1290°/s) and internally rotated (up to 580°/s) reaching its maximum displacement within the first 150 ms after heel strike. Rapid neuromuscular activation bursts of the m. tibialis anterior and the m. peroneus longus started 40-45 ms after ground contact and overshot the activation profile of the reference trials with peak activation at 62 ms and 74 ms respectively. Therefore, it may be suggested that neuromuscular reflexes played an important role in joint control during the critical phase of excessive ankle displacement. The results of this case report clearly indicate that (a) upper leg mechanics, (b) pre-landing adjustments, and (c) neuromuscular contribution have to be considered in the mechanism of lateral ankle sprains.

A new sledge jump system that allows almost natural reactive jumps.

AIM: Sledge jump systems (SJS) are often employed to examine the underlying mechanical and neuromuscular mechanisms of the stretch-shortening cycle (SSC) as they allow the systematic variation of impact velocity and energy. However, in existing SJS the jumps are not very comparable to natural jumps because of the long contact times (∼200%), which prevent the storage of kinetic energy. The aim of the present study was to evaluate if an ultra-light sledge, built in a way that joint movement is barely restricted, allows jumps that are comparable to natural jumps. METHODS: Ground reaction forces, kinematic and electromyographic (EMG) data of 21 healthy subjects were compared between normal hoppings (NH) on the ground and hoppings in a custom-built SJS (sledge hoppings, SH). RESULTS: Normalized to NH, the ground contact times for the SH were prolonged (+22%), while the peak forces (-21%) and the preactivity of the soleus and gastrocnemius medialis muscles were reduced (-20% and -22%, respectively). No significant changes were observed for the iEMG of the short latency response of those muscles (+1% and +8%) and the ranges of motion in the ankle, knee and hip joint (differences of 1, 1 and 2 degrees). The reduced peak forces were associated with a reduced leg stiffness (-21%). CONCLUSION: The new system allows reactive jumps that are rather comparable to natural jumps. Therefore, the new SJS seems to be an adequate system in order to examine the SSC under controlled and almost natural conditions.