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 .

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.

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.

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.

[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.

Effect of soccer shoe cleats on knee joint loads.

Noncontact injuries frequently occur during soccer matches and training. The purpose of this study was to examine the influences of different soccer shoe studs to kinematic, kinetic and electromyographic parameters in the knee joint. Six male soccer players performed complex turning movements (180 degrees ) with bladed and round studded soccer shoes. Ground reaction forces, 3-D kinematics and electromyographic activity of the lower leg muscles were recorded. Calculated external knee joint moments were similar with both stud configurations, although there was a trend towards increased vertical and anterior-posterior ground reaction forces with blades. Electromyography evidenced significantly higher activation of m. quadriceps femoris (p = 0.02) with round studs during initial phase of stance. In conclusion, comparison of soccer shoes with round and bladed studs showed no significant differences in externally applied knee joint loads during a complex injury related movement. The significant increased activation of m. quadriceps femoris with round studs during the critical weight acceptance can be associated with an additional internal load on the anterior cruciate ligament. Therefore, results revealed no higher risk of getting noncontact knee joint injuries with bladed soccer shoes.

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.

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.

Requirements for an enterprise digital image archive.

This report describes several image archival problems facing the authors' department and the results of their attempt to define the requirements for an enterprise digital image archive. The problems identified include the costs of supporting multiple distinct archives, the increased complexity of supporting multiple archive interfaces, the differences in data handling policies and resulting variations in data integrity, and variability in support for nonimage data. The authors also describe the data collected including image volumes and trends and imaging device trends. Finally, the resulting specification for an enterprise digital image archive, including storage and retrieval performance and interface requirements are presented.

Cardiovascular abnormalities with normal blood pressure in tissue kallikrein-deficient mice.

Tissue kallikrein is a serine protease thought to be involved in the generation of bioactive peptide kinins in many organs like the kidneys, colon, salivary glands, pancreas, and blood vessels. Low renal synthesis and urinary excretion of tissue kallikrein have been repeatedly linked to hypertension in animals and humans, but the exact role of the protease in cardiovascular function has not been established largely because of the lack of specific inhibitors. This study demonstrates that mice lacking tissue kallikrein are unable to generate significant levels of kinins in most tissues and develop cardiovascular abnormalities early in adulthood despite normal blood pressure. The heart exhibits septum and posterior wall thinning and a tendency to dilatation resulting in reduced left ventricular mass. Cardiac function estimated in vivo and in vitro is decreased both under basal conditions and in response to beta-adrenergic stimulation. Furthermore, flow-induced vasodilatation is impaired in isolated perfused carotid arteries, which express, like the heart, low levels of the protease. These data show that tissue kallikrein is the main kinin-generating enzyme in vivo and that a functional kallikrein-kinin system is necessary for normal cardiac and arterial function in the mouse. They suggest that the kallikrein-kinin system could be involved in the development or progression of cardiovascular diseases.

Clinician usage patterns of a desktop radiology information display application.

We developed a system for delivering radiologic images and reports to desktop computers used for the electronic medical record (EMR). This system was used by both primary care physicians and specialists primarily in the out-patient setting. The system records all physician interactions with the application to a database. This usage information was then studied in order to understand the value and requirements of an application that could display radiology information (reports and images) on EMR workstations. In this report we describe some of the differences and similarities in usage patterns for the two physician groups. A very high percentage of physicians indicated that having image display capabilities on the workstations was very valuable.

Image display for clinicians on medical record workstations.

Image display on electronic medical record (EMR) workstations is an important step in widespread implementation of picture archiving and communications systems (PACS). We describe a pilot project for implementing image display capability that is integrated with the EMR software, and will allow display of images on the physician's workstation. We believe this pilot will provide valuable information about usage patterns in image display needs, which will be valuable in planning further expansion of PACS in our institution.

READS: a radiology-oriented electronic analysis and display station.

READS is a picture archiving and communications system (PACS) display program that is tailored to allow a radiologist to efficiently perform image review tasks. In this study, the image review process was observed and functional patterns were identified. These were used to define a design that was considered to represent the optimal balance of compromises for a low-cost review station that also allowed easy addition of new functionality. As a result, a program was designed and implemented that has been found to be acceptable for image review and for special image processing function development.

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.

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.

Effect of Hoe 140 on bradykinin-induced bronchoconstriction in anesthetized guinea pigs.

We have investigated the efficacy of the novel, highly potent, and stable B2 bradykinin (BK) antagonist Hoe 140 against BK-induced bronchoconstriction in guinea pigs via whole body plethysmography and compared different routes of administration. Our results clearly demonstrate that Hoe 140 is highly potent at inhibiting bronchoconstriction induced by either intravenous (i.v.) or inhaled BK. Intravenous BK was strongly inhibited by i.v. Hoe 140 (ID50 13.4 pmol/kg), and less by aerosolized Hoe 140 (ID50 1.34 nmol/kg). Aerosolized BK (235 nmol/kg) was strongly inhibited by 0.1 nmol/kg of aerosolized Hoe 140 given 30 min before. Hoe 140 is the first BK antagonist to effectively inhibit the bronchoconstrictor effect of aerosolized BK. The equieffective i.v. dose of Hoe 140, however, as about 100-fold higher. From the discrepancy in efficacy of Hoe 140 against i.v. and aerosolized BK, it was concluded that i.v. BK has no direct effect on the lung, in contrast to inhaled BK. Moreover, the high potency of Hoe 140 in the guinea pig lung does not confirm the hypothesis of a B3 BK receptor. Based on its high potency and good tolerability, Hoe 140 is appropriate to evaluate the role of BK in human airway diseases.