A macropencil beam model: clinical implementation for conformal and intensity modulated radiation therapy.

The increasing use of irregularly shaped, off-centre fields in advanced treatment techniques, particularly intensity modulated radiation therapy, has strained the limits of conventional, broad-beam dose calculation algorithms. More recent models, such as kernel-based pencil beams and Monte Carlo methods, are accurate but suffer from the time needed for calculations and from the lack of clearly established methods for determining the parameters needed to match calculations with the particular dosimetric characteristics of an individual machine. This paper presents the implementation of a model that uses an extended source model to calculate the variation of fluence at the patient surface for any arbitrarily shaped field. It uses a macropencil beam model to calculate phantom scatter. Both head scatter and phantom scatter models use exponential functions fit to a series of measurements to determine the model's parameters. The means by which the model can be implemented in a clinical setting using standard dosimetric equipment is presented. Results for two separate machines and three energies are presented. Comparisons with measurements for a set of regular and irregular fields demonstrate the accuracy of the model for conventional, conformal and intensity modulated treatments. For rectangular and irregular fields at depths up to 20 cm, the accuracy was better than < or =1.5%, compared with errors of up to 7.5% with a standard algorithm. For a 20-step intensity modulated field, the accuracy was 3.4% compared with 18% with the conventional algorithm. The advantages of this model for IMRT are discussed.

Alcohol abuse/dependence in motor vehicle crash victims presenting to the emergency department.

OBJECTIVE: 1) To determine the prevalence of current alcohol abuse/alcohol dependence (AA/AD) among the full injury range of ED motor vehicle crash (MVC) patients; and 2) compare AA/AD and non-AA/AD patient characteristics. METHODS: This was a prospective cohort study using a stratified random sample of MVC patients aged > or = 18 years presenting to a university hospital and university-affiliated community hospital ED from May 1, 1992, to August 30, 1994. A diagnosis of current AA/AD was based on the alcohol section of the Diagnostic Interview Survey (DIS). Other measurements included the presence of blood alcohol (BAC+), Injury Severity Score (ISS-85), occupant status (driver/passenger), age, gender, seat belt use, culpability for crash, and ED disposition (admitted vs released). A weighted prevalence was determined; subgroups were compared using t-tests, chi 2, 2-factor analysis, and logistic regression modeling; alpha = 0.05. RESULTS: 1,161 patients were studied. The weighted prevalence of current AA/AD was 22.5%; 53% of these patients were released from the ED. Almost 45% of the patients with current AA/AD were BAC-. When controlling for BAC and AA/AD, greater injury severity and culpability were associated with a BAC+, but not with current AA/AD. CONCLUSION: Almost 23% of ED MVC patients have current AA/AD; BAC testing does not accurately identify these patients. Intervention strategies must be directed to both admitted and released patients.

Family history of alcoholism and childhood adversity: joint effects on alcohol consumption and dependence.

Empirical studies provide substantial evidence that having a family history of alcoholism increases the risk of developing alcohol dependence; however, some of this effect may be caused by nonspecific childhood socioeconomic adversity common in families with an alcohol-dependent parent. In this study, we examine joint effects of family history and childhood adversity within a sample of 509 men and 217 women over age 40. The measures analyzed were included in routine screening assessments for participants in various studies at the University of Michigan Alcohol Research Center. About 60% of the men and 45% of the women were alcohol-dependent. About 30% reported an alcoholic parent. Degree of family history affected drinking behavior for both men and women. There were also environmental effects on the same measures for both men and women. Childhood socioeconomic adversity was reported more frequently by participants with an alcoholic parent, but adversity effects were also shown for those with a negative family history. The risk of alcohol dependence was additively increased by a positive family history and childhood socioeconomic adversity. The environmental effects identified in this study are promising evidence for nonspecific factors that moderate family history risk for development of alcohol problems.

Stress changes of the distal radial growth plate. A radiographic survey and review of the literature.

We conducted a radiographic survey to determine skeletal age and the nature and prevalence of stress-related changes affecting the distal radial growth plate in 60 young competitive gymnasts (39 females, 21 males). Comparison of results for chronological and skeletal age revealed a significant delay in maturation for girls (P less than 0.001). Radiographic evaluation revealed 5 gymnasts (4 girls and 1 boy) with stress-related changes of the left wrist, and four of these were considered to be minimal. These results, in conjunction with our previous findings and the review of related literature, reveal three important observations. First, the widening and irregularities of the distal radial physis that we described previously appear to be the first in a spectrum of abnormal changes secondary to overuse and probably represent a stress fracture of the distal radial growth plate. The radiographic changes associated with this injury are not the normal adaptive changes seen in young, competitive gymnasts. Secondly, more serious long-term abnormality may result even though the injury may initially resemble a Salter-Harris type I or II stress fracture. Long-term complications may include symmetrical or asymmetrical retardation or halted growth at the affected site, positive ulnar variance, and associated pathoanatomic sequelae. Thirdly, the incidence of distal radial growth plate stress injury remains unclear; we recommend a further, large-scale prospective epidemiologic study involving both male and female gymnasts. We urge that physicians and other health professionals associated with gymnastics clubs educate coaches about the possibility of significant injury to the distal radial physis, risk factors, and suggested preventive measures.

Retrospective direct comparison of three intraarticular anterior cruciate ligament reconstructions.

A long-term retrospective study (minimum 5 years) was done looking at three groups of anterior cruciate deficient knee patients using both subjective and objective anterior cruciate tests. Twenty-seven chronic anterior cruciate ligament deficient knees reconstructed with the middle third of the patellar tendon and 28 chronic anterior cruciate ligament deficient knees reconstructed with the semitendinosus tendon were included in this consecutive group of patients and were felt to be directly comparable. It was found that the chronic anterior cruciate ligament deficient group reconstructed with the semitendinosus tendon had 4 excellent, 10 good, 7 poor, and 7 failures with an objective score averaging 4.5 of a possible 12, while the comparable group reconstructed with the middle third of the patellar tendon had 16 excellent, 7 good, 3 poor, and only 1 failure with a score of 10 of a possible 12 (P less than 0.0032). For completeness sake, 20 anterior cruciate deficient knees from this group of consecutive patients that were reconstructed acutely with the semitendinosus tendon were also examined. This group had 8 excellent results, 9 good, 3 poor, and no failures with a score of 9.8 (P less than 0.03 compared to the other group using the semitendinosus tendon). This comparison between the two groups where the semitendinosus tendon was used in the anterior cruciate ligament reconstruction was made only to show the difference between studies dealing with knee reconstructions. There may be a significant difference between a study dealing with acutely reconstructed knees versus one focusing on chronically reconstructed knees, most likely because of both patient selection and time between injury and reconstruction.(ABSTRACT TRUNCATED AT 250 WORDS)

Meniscal cysts.

Meniscal cysts are cysts that occur as a direct extension, or within the substance of the meniscus. The incidence varies in reports from 1% to 20% and are much more common laterally. They usually present as joint-line pain, swelling, or both in young adult men, and are often associated with meniscal tears. The exact etiology of meniscal cysts is unknown. A myxoid degenerative process is identified histologically. There is often a history of precedent trauma. Diagnosis is often suspected clinically and can be confirmed by arthrogram, CT, or MRI when necessary. Conservative treatment in the patient with few symptoms is recommended. Should the cyst become significantly symptomatic, it is necessary to treat the meniscal pathology to prevent a cyst recurrence. At the present time it is our recommendation that this be done by arthroscopically resecting the meniscus back to normal meniscus and either aspirating and injecting the cyst with steroid or local cyst excision if the aspiration and injection fails. If no meniscal tear is documented at arthroscopy, exploration and excision of the cyst are recommended.

Instrumented Lachman tests for the evaluation of anterior laxity after reconstruction of the anterior cruciate ligament.

Using a KT-1000 arthrometer, in fifty subjects were measured the anterior ligamentous laxity in a knee in which the anterior cruciate ligament had been reconstructed and in the normal, contralateral knee. We also determined the anterior tibial displacement and anterior compliance, using the Lachman test. The subjects were divided into groups according to the type of autogenous intra-articular substitute (either the central one-third of the patellar tendon or the semitendinosus tendon) that had been used for the anterior cruciate ligament and according to the duration of follow-up (range, twenty-four to 101 months). Lachman tests were performed, applying sixty-eight and ninety newtons of force, and indices for anterior compliance were calculated. Although significantly more anterior laxity was demonstrated with both sixty-eight and ninety newtons of force in the reconstructed knees than in the contralateral, normal knees (p less than 0.001), thirteen subjects, of whom eight lacked full extension of the reconstructed knee, had more anterior laxity in the normal knee. Analyses of variance showed no significant differences in the results of the Lachman tests as related to either the type of reconstruction or the length of postoperative follow-up. The results suggested that the two types of ligamentous substitute that were used in this study were equally efficient in limiting anterior tibial displacement, as demonstrated by the Lachman test. The study also demonstrated that the substitutes did not elongate significantly during the period of the study.

Long-term evaluation of knee stability and function following surgical reconstruction for anterior cruciate ligament insufficiency.

Currently used measures of knee stability and function for ACL reconstructed knees have not gained universal acceptance. Clinical test results often are given more value than the patient's subjective evaluation of the surgical outcome. This study was designed to identify specific knee stability and function variables that were most predictive of the patient's rating of knee function following one of two types of combined (intraarticular and extraarticular) ACL reconstruction procedures. Individual measures of knee stability and function were also evaluated for differences between contralateral operated and nonoperated limbs. Postoperative and healthy contralateral knees of 51 male and female patients aged 18 to 49 years (mean, 23.7 years) were evaluated on a battery of tests at an average of 48.0 months after surgery (range, 24 to 101 months). All subjects possessed a normal contralateral knee for comparative purposes. The results of this retrospective study indicated that the variables selected were not highly correlated with, nor could they effectively predict, the patients' perceptions of postoperative knee status as measured by the Knee Function Rating Form (KFR). Statistically significant differences (P less than 0.001) between operated and nonoperated knees were found for 9 of 11 variables analyzed. The data suggest that patients' perceptions of postoperative knee status were independent of the results of static and dynamic clinical tests commonly used to assess knee stability and function. Postoperative deficits of up to 30% between the surgically reconstructed and normal contralateral knees on specific measures of knee stability and function did not greatly influence the patients' perceptions of knee function. Development of new, more specific dynamic tests may be necessary before stronger relationships between clinical test results and patients' perceptions of knee status in the ACL reconstructed knee can be realized.

Stress changes of the distal radial epiphysis in young gymnasts. A report of twenty-one cases and a review of the literature.

Between 1980 and 1983, 21 young, high-performance gymnasts with stress changes related to the distal radial epiphysis, were treated and followed for a mean of 24 months (range, 6 to 42 months). Eleven of the gymnasts presented with roentgenographic changes of the distal radial epiphysis, and in these recovery took at least 3 months. This group was compared to a group of ten gymnasts who had similar symptoms but no roentgenographic changes, and who recovered within an average of 4 weeks. The roentgenographic changes, which are described in detail, are considered to represent stress changes, possibly stress fractures, of the distal radial epiphysis. No residual growth-related problems have been observed. Possible etiologic factors are discussed, and the literature as it pertains to stress-related adaptation and injury in the growing athlete is reviewed.

Knee problems in children and adolescents.

It is important to recognize that there are differences in the spectrum of knee injuries that occur in childhood and adolescence and to always keep these in mind when examining the younger athlete. Constant vigilance for hip pathology presenting as knee pain is also necessary in this age group. As the tendency becomes greater for practitioners to become more specialized in treatment modalities (for example, arthroscopic surgeons, knee surgeons, and so forth), the likelihood of making preventable errors in the case of young athletes increases. The comprehensive care of the athlete and his or her injury is paramount, and one should be wary of the pressure to treat the youngster as one might the college or professional athlete in order to return him or her to sports more quickly. Serious injuries require time to heal and even more time for the patient to convalesce and undergo rehabilitation.

Osteochondrosis of the humeral capitellum.

Seven cases of osteochondrosis of the capitellum occurring in five high performance female gymnasts between the ages of 11 and 13 are presented. Two of the patients were treated by surgical excision of the loose osteochondral fragment in three elbows. Four of the five gymnasts, including the two who underwent surgical treatment, were able to return to full workouts without recurrence of symptoms within the 3 year followup. All conditions in gymnasts were detected after symptoms had presented. A survey of 37 actively competing gymnasts at a nationally known gymnastics academy was performed, including a detailed history and physical examination and radiographic examination. No other cases of osteochondrosis were detected. It was postulated that this condition represents a lateral compression injury because of repetitive valgus overload. Investigation of the capitellar blood supply indicates that the common factors in osteochondrosis of the capitellum are repetitive or prolonged trauma to a vulnerable epiphysis on a basis of vascular interruption. Gymnastics maneuvers require forceful weight-bearing through the upper extremities. Medical personnel and coaches associated with gymnastics need to be aware of the condition of osteochondrosis of the capitellum so that any gymnast who presents with a painful, tender, swollen or locked elbow is appropriately investigated and treated.

Patellofemoral disorders: physical and radiographic evaluation. Part I: Physical examination.

Patellofemoral disorders present a diagnostic and therapeutic challenge to the orthopedic surgeon. By the sequential application of such basic diagnostic tools as inspection, palpation, and various measurements to a patient in standing, sitting, supine, and prone positions, a reproducible, comprehensive physical examination of the patellofemoral joint and entire lower extremity may be achieved.

Patellofemoral disorders: physical and radiographic evaluation. Part II: Radiographic examination.

Evaluation of the patient with patellofemoral complaints requires a comprehensive physical and radiologic investigation. The tangential view is most helpful in the evaluation of such patellofemoral disorders as chondromalacia, lateral patellar compression syndrome, and recurrent subluxation or dislocation. Commonly utilized tangential views include those described by Hughston, Merchant, Laurin, and Ficat. Multiple calculations available for quantitation of abnormal tangential views include the sulcus angle, congruence angle, lateral patellofemoral angle, patella index, and patellofemoral index. Lateral radiographic views commonly utilized to evaluate the patellofemoral joint for patella alta or infera include those described by Blumensaat, Labelle and Laurin, and Insall and Salvati. Utilization of all of the available patellofemoral radiographic views and calculations is impractical and unnecessary. However, to ensure diagnostic accuracy, a routine consisting of a reproducible radiographic technique and various, easily performed calculations that aid in diagnosis must be adopted.

Reconstruction procedures for anterior cruciate ligament insufficiency: a computer analysis of clinical results.

A pre- and postoperative study of 205 patients who had surgical reconstruction of the anterior cruciate ligament (ACL) of the knee was evaluated with the use of a prototype computer program. An average followup of 4.1 years revealed a 27% improvement in subjective complaints and a 8% improvement in objective findings. The anterior drawer test was improved 25% and subluxation of the lateral tibial plateau (ALRI) was improved 118% correlating highly (P less than 0.001) with a good result. Seventy-four percent of patients had undergone medial meniscectomy, 58% lateral meniscectomy, and 41% had both menisci removed at followup after reconstruction. Ninety-two percent of the 121 patients responding to a final subjective complaint evaluation felt that their knee was significantly improved (average 6.1 years after reconstruction). The computer demonstrated a wide variation in the results of reconstruction within the intraarticular, extraarticular, and combined groups. The addition of associated procedures to the main reconstructive procedure significantly affected the results. This study reveals improvement of subjective complaints and objective findings after reconstructing the anterior cruciate ligament and proposes the use of computer analysis for specific evaluation of different procedures.

Little League survey: the Eugene study.

In a clinical and radiographic survey of the elbows of 120 pitchers ages 11 and 12, 20% were found to have symptoms, 10% flexion contractures, and 23% roentgenographic changes related to traction stresses on the medial side of the elbow. Five per cent had more serious lateral compression findings related to the radial head or capitellum, but none of these had symptoms. Although this represents a definite incidence of abnormal occurrence, there were no statistically significant correlations or interrelations found relating to pitching experience, valgus elbow deformities, symptoms, flexion contractures, or x-ray findings.

Clinical test for anterolateral rotary instability of the knee.

A simplified test for anterolateral rotary subluxation of the knee is largely based on the concepts described by Galway and McIntosh although performed in a different manner. The examiner places the right hand gently on the lateral side of the knee with the thumb overlying the posterior aspect of the fibula and the index finger palpating the anterolateral aspect of the joint line to determine the the tibiofemoral relationship. The left hand embraces the lateral side of the distal end of the femur with the thumb over the posterior aspect of the lateral femoral condyle. With equal pressure on the lateral femoral condyle and fibular head the knee is pushed gently forward into flexion. When anterointernal tibial luxation is present, a reduction phenomenon is felt as the knee passes into the 25 to 40 degree flexion range. This may occur as a sudden palpable and occasionally audible repositioning which is responsible for such terminology as a "pivot shift" or "jerk sign." We have experienced many instances where the reduction phenomenon is more subtle and is determined by palpation alone. The pathologic mechanics are determined by observations at surgery in 45 patients with a positive test. This test has improved our diagnositc ability and is easly taught to those unfamiliar with knee joint disorders.