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Biomedical subjects

M Fredericson

Publications and source records attributed to M Fredericson.

12 recordsLinked to original sources
PubMed2006

Is cartilage thickness different in young subjects with and without patellofemoral pain?

OBJECTIVE: To determine the differences in load-bearing patellofemoral joint cartilage thickness between genders. To determine the differences in load-bearing cartilage thickness between pain-free controls and individuals with patellofemoral pain. METHODS: The articular cartilage thickness of the patella and anterior femur was estimated from magnetic resonance images in 16 young, pain-free control subjects (eight males, eight females) and 34 young individuals with patellofemoral pain (12 males, 22 females). The average age of all subjects was 28+/-4 years. The cartilage surfaces were divided into regions approximating the location of patellofemoral joint contact during knee flexion. The mean and peak cartilage thicknesses of each region were computed and compared using a repeated-measures Analysis of Variance. RESULTS: On average, males had 22% and 23% thicker cartilage than females in the patella (P < 0.01) and femur (P < 0.05), respectively. Male control subjects had 18% greater peak patellar cartilage thickness than males with patellofemoral pain (P < 0.05); however, we did not detect differences in patellar cartilage thickness between female control subjects and females with patellofemoral pain (P = 0.45). We detected no significant differences in femoral cartilage thickness between the control and pain groups. CONCLUSIONS: Thin cartilage at the patella may be one mechanism of patellofemoral pain in male subjects, but is unlikely to be a dominant factor in the development of pain in the female population.

Adult↗
PubMed2000

Hip abductor weakness in distance runners with iliotibial band syndrome.

OBJECTIVE: To examine hip abductor strength in long-distance runners with iliotibial band syndrome (ITBS), comparing their injured-limb strength to their nonaffected limb and to the limbs of a control group of healthy long-distance runners; and to determine whether correction of strength deficits in the hip abductors of the affected runners through a rehabilitation program correlates with a successful return to running. DESIGN: Case series. SETTING: Stanford University Sports Medicine Clinics. PARTICIPANTS: 24 distance runners with ITBS (14 female, 10 male) were randomly selected from patients presenting to our Runners' Injury Clinic with history and physical examination findings typical for ITBS. The control group of 30 distance runners (14 females, 16 males) were randomly selected from the Stanford University Cross-Country and Track teams. MAIN OUTCOME MEASURES: Group differences in hip abductor strength, as measured by torque generated, were analyzed using separate two-tailed t-tests between the injured limb, non-injured limb, and the noninjured limbs of the control group. Prerehabilitation hip abductor torque for the injured runners was then compared with postrehabilitation torque after a 6-week rehabilitation program. RESULTS: Hip abductor torque was measured with the Nicholas Manual Muscle Tester (kg), and normalized for differences in height and weight among subjects to units of percent body weight times height (%BWh). Average prerehabilitation hip abductor torque of the injured females was 7.82%BWh versus 9.82%BWh for their noninjured limb and 10.19%BWh for the control group of female runners. Average prerehabilitation hip abductor torque of the injured males was 6.86%BWh versus 8.62%BWh for their noninjured limb and 9.73%BWh for the control group of male runners. All prerehabilitation group differences were statistically significant at the p < 0.05 level. The injured runners were then enrolled in a 6-week standardized rehabilitation protocol with special attention directed to strengthening the gluteus medius. After rehabilitation, the females demonstrated an average increase in hip abductor torque of 34.9% in the injured limb, and the males an average increase of 51.4%. After 6 weeks of rehabilitation, 22 of 24 athletes were pain free with all exercises and able to return to running, and at 6-months follow-up there were no reports of recurrence. CONCLUSIONS: Long distance runners with ITBS have weaker hip abduction strength in the affected leg compared with their unaffected leg and unaffected long-distance runners. Additionally, symptom improvement with a successful return to the preinjury training program parallels improvement in hip abductor strength.

Adolescent↗
PubMed1998

Shoulder MRI after impingement test injection.

OBJECTIVE: To determine how long injected fluid from an impingement test remains in the bursa or adjacent soft tissues after an injection. DESIGN AND PATIENTS: Six patients prospectively underwent MRI of the shoulder immediately before and after an impingement test injection, and at 3 days, 2 weeks and 4 weeks later. MR images were evaluated and graded for fluid distribution within the bursa and adjacent soft tissues. The rotator cuff was evaluated for signal abnormalities related to the injection. RESULTS AND CONCLUSION: Three days after the injection, the soft tissue fluid had returned to pre-injection levels or less in five of the six patients. No patients showed rotator cuff signal abnormalities related to the impingement test injection. We recommend a delay of 3 days before a shoulder MR examination after an injection has been performed, to avoid misinterpretations.

Adult↗
PubMed1997

[Stress fractures in athletes].

Stress fractures are one of the most common overuse injuries seen in athletes, accounting for up to 20% of all injuries presented to sports medicine clinics. Runners are particularly prone to these injuries, however, it is difficult to predict injury as there is usually a critical interplay between the athlete's biomechanical predisposition, training methods, and other factors such as diet, and muscle strength and flexibility. This article will discuss the key clinical findings for the majority of stress fractures encountered in a sports medicine practice. A classification scheme will also be described that will allow the clinician to make appropriate treatment decisions based on the degree of risk for each injury.

Athletic Injuries↗
PubMed1996

Common injuries in runners. Diagnosis, rehabilitation and prevention.

Most injuries to runners involve a critical interplay between an individual's biomechanical predisposition and some recent change in their training programme. This may involve a rapid increase in weekly distance, intensity, or frequency of hill or track workouts. This review emphasises that a through understanding of the anatomy, pathophysiology, and predisposing biomechanical factors is essential for adequate injury treatment and prevention. As a sports medicine spedialist, it is also important to be familiar with the wider differential diagnosis for each of the common running injuries seen in a sports medicine clinic. In addition, all female runners should be questioned regarding any history of menstrual or eating dysfunction that can contribute to lowered bone mineral density and higher risk of injury. Because these injuries are related to cumulative overload of the lower extremity, they often come on insidiously and a strong index of suspicion is necessary for prompt detection. The vast majority of injuries, when identified early on, can be treated effectively with minor modifications in the training programme, correction of underlying muscle and flexibility imbalances, and attention to appropriate footwear.

Athletic Injuries↗
PubMed1983

Mediation of skin temperature biofeedback effects in children.

Three studies are reported that, in general, fail to replicate an earlier investigation by this laboratory ( Suter & Loughry - Machado , 1981) in which impressive self-regulation of skin temperature by children was obtained. Mediation of skin temperature biofeedback effects is discussed. It is concluded that biofeedback self-regulation cannot be understood independently of the interpersonal, attitudinal, and cognitive context in which it occurs.

Adult↗
PubMedDate not supplied

Changes in posterior disc bulging and intervertebral foraminal size associated with flexion-extension movement: a comparison between L4-5 and L5-S1 levels in normal subjects.

BACKGROUND CONTEXT: No previous study has used magnetic resonance imaging (MRI) to evaluate changes of posterior disc bulging and intervertebral foraminal size in the normal spine with flexion-extension movement, comparing L4-5 versus L5-S1 intervertebral levels. PURPOSE: To determine changes in posterior disc bulging and intervertebral foraminal size with flexion-extension movement, comparing L4-5 versus L5-S1 intervertebral levels. STUDY DESIGN: An in vivo study of magnetic resonance kinematics with spine flexion extension. METHODS: Spines of three volunteers with no history of low back pain were scanned in neutral, flexion, and extension positions in a vertically open MRI system. MRI was repeated after 6 hours of normal activity and an additional 4 hours of heavy activity with a weighted vest. Posterior bulging of the intervertebral disc and the size of intervertebral foramen were measured at the L4-5 and L5-S1 levels. RESULTS: With spine flexion, posterior bulging of the discs increased at L4-5 in eight of nine measurements (three different spine-loading states for each of three subjects) and L5-S1 discs in six of nine measurements. In most cases, posterior bulging decreased with extension. No significant difference was noted in the degree of disc bulge between levels. Foraminal size at L4-5 increased with flexion and decreased with extension, and the extent of these changes was greater at the L4-5 level than at L5-S1. CONCLUSIONS: This pilot study demonstrates two distinct behavior characteristics of the normal spine with flexion-extension movement.

Adult↗
PubMedDate not supplied

Tibial stress reaction in runners. Correlation of clinical symptoms and scintigraphy with a new magnetic resonance imaging grading system.

Medial tibial pain in runners has traditionally been diagnosed as either a shin splint syndrome or as a stress fracture. Our work using magnetic resonance imaging suggests that a progression of injury can be identified, starting with periosteal edema, then progressive marrow involvement, and ultimately frank cortical stress fracture. Fourteen runners, with a total of 18 symptomatic legs, were evaluated and, within 10 days, referred for radiographs, a technetium bone scan, and a magnetic resonance imaging scan. In 14 of the 18 symptomatic legs, magnetic resonance imaging findings correlated with an established technetium bone scan grading system and more precisely defined the anatomic location and extent of injury. We identified clinical symptoms, such as pain with daily ambulation and physical examination findings, including localized tibial tenderness and pain with direct or indirect percussion, that correlated with more severe tibial stress injuries. When clinically warranted, we recommend magnetic resonance imaging over bone scan for grading of tibial stress lesions in runners. Magnetic resonance imaging is more accurate in correlating the degree of bone involvement with clinical symptoms, allowing for more accurate recommendations for rehabilitation and return to impact activity. Additional advantages of magnetic resonance imaging include lack of exposure to ionizing radiation and significantly less imaging time than three-phase bone scintigraphy.

Adolescent↗