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Biomedical subjects

D H Janda

Publications and source records attributed to D H Janda.

At least 19 recordsLinked to original sources
PubMed2001

A comparison of standard vs. breakaway bases: an analysis of a preventative intervention for softball and baseball foot and ankle injuries.

More than 40 million individuals participate in organized baseball and softball leagues in the United States every year. Unfortunately, it has also been estimated by the Consumer Product Safety Commission that softball and baseball are the two main sports leading to emergency-room visits in the United States. A previous field study has determined that the utilization of breakaway bases has the potential of preventing 96% of sliding injuries, thereby preventing 1.7 million injuries a year in the United States with a savings of $2 billion a year in health care costs. It is the purpose of this study to analyze and compare the potential attenuating capabilities of various types of bases. We found the force at the ankle upon impact when compared to the standard base revealed all breakaway bases reduced the force of impact to a statistically significant level. The force at the foot upon impact when compared to the standard base revealed all breakaway bases reduced the force at variable levels, with the Rogers bases having the only statistically significant reduction. However, the force delivered to the tibia/fibula was increased with the Stay Down and Mag-Net large bases as compared to the standard stationary base. The moments of inversion/eversion and dorsiflexion/plantar flexion upon impact, when compared to the standard base, revealed all safety bases were reduced to a statistically significant level. We conclude breakaway bases reduce the force of impact and moments to a statistically significant level and confirm previous field studies. Though there is a difference among the breakaway bases themselves, they should be used on all fields.

Adult↗
PubMed2000

Prevention of commotio cordis in baseball: an evaluation of chest protectors.

BACKGROUND: In a recent study of fatal chest impacts by baseballs, 28% of the children were wearing a chest protector. This study evaluates the effectiveness of chest protectors in reducing the risk of commotio cordis. METHODS: Five commercially available chest protectors were placed on a three-rib structure simulating the chest and impacted at 40, 50, 60, and 70 miles per hour by a standard baseball. Ten repeated tests were conducted on each vest in random order, and on the control (unprotected chest). The viscous response (or viscous criterion [VC]) was used to assess differences in fatality risk. RESULTS: One vest had a statistically lower VC (average, 50.6%, p < 0.05) for all impact speeds. Three averaged 18.7% to 27.7% lower VC, but were significantly different only at higher speeds. One vest had an average 34.2% higher VC, and was significantly higher at 40 to 50 miles per hour (p < 0.05). A method was proposed linking laboratory test results to real-world incidents of ventricular fibrillation. CONCLUSIONS: The majority of commercially available chest protectors fail to provide consistent reductions in commotio cordis risk. Nonetheless, there are benefits from their use in baseball until improved safety equipment is developed and standard tests are established to assess sport equipment effectiveness.

Athletic Injuries↗
PubMed1998

Blunt chest impacts: assessing the relative risk of fatal cardiac injury from various baseballs.

OBJECTIVE: To compare various soft-core baseballs for their ability to reduce the risk of fatal chest-impact injury. DESIGN: This study used a three-rib biomechanical surrogate to quantitatively analyze chest impacts from nine soft-core baseballs and one standard baseball, which served as the control. Impacts were achieved with an air cannon system, with the velocity of impact being 40, 50, and 60 mph. MATERIALS AND METHODS: The deflection of the three-rib structure at the sternum was measured and used to calculate the viscous criterion, which correlates with risk of chest-impact injury. MEASUREMENTS AND MAIN RESULTS: Analysis showed that baseballs with lighter mass had a significantly lower viscous criterion (p < 0.05). Those with a similar mass had no change in the viscous criterion, and the heaviest soft-core baseball had a significantly higher viscous criterion at an impact velocity of 60 mph. CONCLUSION: The results of this study indicate that soft-core baseballs may not differ from a standard baseball with regard to the risk of fatal chest-impact injury while playing baseball. Other techniques, such as preventive coaching, need to be implemented when trying to improve baseball safety.

Baseball↗
PubMed1997

Sports injury surveillance has everything to do with sports medicine.

Injury is the most under-recognised major public health problem facing the world community. In addition to being an enormous public health issue, injuries continue to usurp our limited healthcare financial resources. It therefore becomes imperative that comprehensive injury occurrence data systems be developed in order to: (i) identify risk factors and types of injuries; (ii) help determine the effectiveness of preventative intervention; and (iii) delineate the costs of injury in order to develop financial resource planning.

Athletic Injuries↗
PubMed1995

An analysis and comparison of soccer shin guards.

Worldwide > 40 million amateurs participate in the team sport of soccer. With 647,368 injuries occurring from 1989 through 1992, the risk of injury during the play of soccer is evident. Lower extremity injuries have been found to comprise 13.1% of the total injuries in soccer. To date, a comprehensive evaluation of protective equipment utilized to prevent lower extremity injuries in soccer has been lacking. This study utilized a 5th percentile Hybrid III female dummy to evaluate the effectiveness of shin guards in attenuating the forces which can lead to lower extremity injuries. A pendulum impact apparatus simulated one player being kicked by another. Impacts were delivered to the anterior tibial region of the Hybrid III dummy and peak loads were recorded. Load forces were reduced 41.2-77.1% with the utilization of shin guards. Even at extreme temperatures, the guards were found to be effective in lowering the amount of impact force transferred to the shin region. The results of this study indicate that the use of shin guards will attenuate the force of impact to the tibia and thus reduce the risk of injury.

Athletic Injuries↗
PubMed1992

Softball injuries. Aetiology and prevention.

Over 40 million individuals nationally participate in organised softball leagues, playing an estimated 23 million games per year in the United States. It has also been estimated that softball causes more injuries leading to emergency room visits in the United States than any other sport. Between 1983 and 1989, over 2.6 million injuries were documented through selected emergency rooms throughout the United States. In addition, the potential costs of these injuries can be staggering, therefore, prevention is of utmost importance. Prior to implementation of any preventative measures, the aetiology and distribution of injuries must be ascertained. Softball-related injuries can be grouped into 3 categories: (a) sliding-related injuries--the most common injury scenario; (b) collision-related injuries; and (c) falls sustained by the player. Various preventative approaches have been utilised to reduce the incidence of these recreational sports injuries and the associated health care costs. In regard to sliding-related injuries, breakaway bases have been utilised and have been found to reduce sliding-related injuries by approximately 98%. In reference to collision injuries, deformable walls and padded back stops and field maintenance have been found to prevent the majority of injuries secondary to collisions and falls. In addition, better coaching techniques as well as stretching and conditioning programmes have all been found to benefit players in the prevention of their injuries. As physicians, trainers and individuals involved with sporting activities, it is imperative that we turn and focus our attention on prevention. The cornerstone to diminished injuries and subsequent prevention of an injury is a safer environment for the recreational softball player to participate in.

Athletic Injuries↗
PubMed1991

Basic science and clinical application in the athlete's shoulder. A preventative program focusing on the glenohumeral joint.

This program can be implemented as either a preventative program or a rehabilitative program for the upper extremity in the throwing athlete or in nonthrowing athletes involved in overhead activities. The authors have found this program to be easily employed in a university setting. The keystone to its effectiveness is the participating individual. For optimal results, it should be performed as specifically outlined. The likelihood that shoulder symptomatology will develop is higher now that more people are participating in recreational and team sports for cardiovascular fitness. It is, therefore, imperative that a preventative program be developed in both the recreational and professional athletic population.

Athletic Injuries↗
PubMed1990

Nonhuman primate bites.

Nonhuman primate (monkey) bites to researchers and attending animal care staff may present problems in patient management. Such inoculations can transmit serious bacterial and viral infections to the human handlers. Significant local and systemic manifestations can subsequently develop following such an injury. Since Herpesvirus simiae (B virus) is enzootic in Asiatic monkeys of the genus Macaca, and since B virus infection in humans is usually fatal, additional prophylactic and therapeutic measures must be taken when persons are bitten by macaque monkeys. Primate bites require early aggressive intervention.

Acyclovir↗
PubMed1988

Softball sliding injuries. A prospective study comparing standard and modified bases.

In a previous retrospective study, base sliding was found to be responsible for 71% of recreational softball injuries. As most injuries occurred following rapid deceleration impact against stationary bases, quick-release (breakaway) bases were evaluated as a means to modify this mechanism of injury. Six hundred thirty-three softball games were played on breakaway-base fields and 627 games were played on stationary-base fields. Forty-five sliding injuries (7%) occurred on the stationary-base diamonds and only two sliding injuries (less than 1%) occurred on the breakaway-base fields. Implementing the use of breakaway bases in recreational softball leagues could potentially achieve a significant, cost-effective reduction of injuries.

Adult↗
PubMed1987

Objective evaluation of grip strength.

The objective and subjective components of industry-related injuries can lead to difficulties in diagnosis and treatment efforts. Grip strength determinations provide an objective measure that facilitates the evaluation of many occupation-related injuries. In this current study, healthy volunteers were evaluated with standard grip strength measurement and electromyographic recordings in order to characterize normal patterns. These recordings were found to be relatively uniform and reproducible.

Disability Evaluation↗
PubMedDate not supplied

Reliability of radiographic assessment of acromial morphology.

The most widely used radiographic classification system for acromial morphology identifies three distinct acromial shapes: type I (flat), type II (curved), and type III (hooked). The purpose of this study was to measure the interobserver and intraobserver reliability of determinations of acromial morphology as defined by this system. Between 1990 and 1992, one hundred twenty-six supraspinatus outlet radiographs were obtained from 126 patients by technicians from Triangle Orthopaedic Associates in Durham, N.C. Six fellowship-trained shoulder surgeons independently reviewed each radiograph and classified it as type I, II, or III on the basis of established guidelines. Two surgeons classified each film a second time in random order. Analysis of variance was performed to obtain coefficients for interobserver and intraobserver reliability. Consensus ratings were then used to classify the 126 radiographs into consensus type I, consensus type II, or consensus type III groups. Percentages of type I, II, and III individual ratings within each consensus group were determined. The intraobserver reliability coefficient was 0.888, interpreted as good to excellent reliability. The interobserver reliability coefficient was 0.516, interpreted as poor to fair reliability. Of the 126 radiographs, 26 (20.6%) were rated as consensus type I, 76 (60.3%) were rated as consensus type II, and 24 (19.1%) were rated as consensus type III. The reliability of observer ratings was lowest when delineation between acromial types II and III was required. The low interobserver reliability makes comparisons of studies by different authors difficult to interpret and obscures the true incidence of acromial morphologic types. It also questions reported correlations between acromial type and shoulder pathologic conditions. It is concluded that a system that incorporates more objective classification criteria and acknowledges the continuous nature of acromial morphologic types may improve interobserver reliability and validate the system's use in making clinical and surgical judgments.

Acromion↗
PubMedDate not supplied

Translation of the glenohumeral joint with the patient under anesthesia.

This study was undertaken to determine glenohumeral translation in the anesthetized patient. Radiographically assessed humeral translation was measured in 18 members of a control group, 10 patients with anterior instability, and 10 patients with multidirectional instability. In the control group stress radiographs revealed anterior translation of 17% (percentage of the diameter of the glenoid from anterior to posterior), posterior of 26%, and inferior to 29% (percentage of diameter of glenoid from superior to inferior). In patients with anterior instability anterior translation was 29%, posterior translation was 21%, and inferior translation was 49%. In patients with multidirectional instability anterior translation was 28%, posterior translation was 52%, and inferior translation was 46%. Overlap in translation was seen between normal members and those with instability. The most practical method to grade anterior and posterior translation of the humeral head within the glenoid fossa involves a clinical assessment of where the center of the humeral head rests in reference to the glenoid rim.

Adolescent↗
PubMedDate not supplied

The Bankart repair illustrated in cross-section. Some anatomical considerations.

The Bankart repair for chronic anterior shoulder instability effectively addresses the pathologic components responsible for repeated dislocation or subluxation. However, contrary to popular belief, the Bankart repair does not precisely restore the premorbid anatomy. The capsule is reattached to the boney rim of the anterioinferior glenoid deep to and lateral to the torn cartilagenous labrum, thus excluding the labrum from the joint anteriorly. This was demonstrated by cross-sectional cadaver dissections performed to illustrate this complex surgical anatomy to orthopaedic residents in training. In addition, when correlated with double-contrast computerized axial tomography, we noted five predominant patterns of anatomical lesions which by common use have been collectively termed the "Bankart lesion." These are: 1) the rare "classic" Bankart lesion in which the cartilagenous labrum and capsular origin are torn from the glenoid rim; 2) the capsule stripped from the scapular neck and the labrum detached from the glenoid rim remaining fixed to the overlying capsule; 3) the capsule stripped from the scapular neck and the labrum separated from the glenoid rim, but separately; 4) the labrum abraded away and no longer radiographically detectable; and 5) glenoid rim fracture.

Humans↗
PubMedDate not supplied

A three-phase analysis of the prevention of recreational softball injuries.

Recreational sports injuries are expensive to society. Prevention of such injuries must be a major public health goal. In a previous retrospective study, base sliding was found to be responsible for 71% of recreational softball injuries. Because most injuries occurred during rapid deceleration against stationary bases, quick-release (break-away) bases were evaluated as a means to modify this mechanism of injury. In a prospective study, 633 softball games were played on a break-away base fields and 627 games were played on stationary base fields. Forty-five sliding injuries occurred on the stationary base diamonds (1 injury for every 13.9 games) and only two sliding injuries occurred on the break-away fields (1 injury for every 316.5 games). The medical costs for injuries on the stationary base fields was 79 times greater than that on the break-away fields. In a 1035 game follow-up study performed on all fields equipped with break-away bases, two sliding injuries occurred (1 injury for every 517.5 games). Installing break-away bases in fields used by recreational leagues would achieve a significant reduction of serious softball injuries (98%) and, therefore, should be mandatory. Based on our findings, the Centers for Disease Control has estimated 1.7 million injuries would be prevented nationally per year, saving $2.0 billion per year nationally in acute medical care costs.

Adolescent↗