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Biomedical subjects

J J Irrgang

Publications and source records attributed to J J Irrgang.

At least 19 recordsLinked to original sources
PubMed2005

Neuromuscular and biomechanical characteristic changes in high school athletes: a plyometric versus basic resistance program.

BACKGROUND: In order to improve neuromuscular and biomechanical characteristic deficits in female athletes, numerous injury prevention programs have been developed and have successfully reduced the number of knee ligament injuries. However, few have investigated the neuromuscular and biomechanical changes following these training programs. It is also largely unknown what type of program is better for improving the landing mechanics of female athletes. OBJECTIVES: To investigate the effects of an 8 week plyometric and basic resistance training program on neuromuscular and biomechanical characteristics in female athletes. METHODS: Twenty seven high school female athletes participated either in a plyometric or a basic resistance training program. Knee and hip strength, landing mechanics, and muscle activity were recorded before and after the intervention programs. In the jump-landing task, subjects jumped as high as they could and landed on both feet. Electromyography (EMG) peak activation time and integrated EMG of thigh and hip muscles were recorded prior to (preactive) and subsequent to (reactive) foot contact. RESULTS: Both groups improved knee extensor isokinetic strength and increased initial and peak knee and hip flexion, and time to peak knee flexion during the task. The peak preactive EMG of the gluteus medius and integrated EMG for the gluteus medius during the preactive and reactive time periods were significantly greater for both groups. CONCLUSIONS: Basic training alone induced favourable neuromuscular and biomechanical changes in high school female athletes. The plyometric program may further be utilised to improve muscular activation patterns.

Adolescent↗
PubMed2001

A pilot study on the relationship between physical impairment and activity restriction in persons with anterior cruciate ligament reconstruction at long-term follow-up.

This study examined the relationship between impairment of the knee and activity restriction during activities of daily living and sports following anterior cruciate ligament reconstruction. Knee range of motion, swelling, pain, instability, ligamentous laxity, isometric and isokinetic muscle function and performance-based measures of activity restriction were measured in 44 subjects. Four measures of patient-reported activity restrictions, including the Activities of Daily Living, Sports Activities Scales of the Knee Outcome Survey, and global ratings of function during activities of daily life and sports, were statistically combined to create a composite variable representing the level of patient-reported activity restrictions for each subject. Hierarchical regression analysis revealed that 17% of the variability in patient-reported activity restrictions was accounted for by age, length of postoperative follow-up, and mechanism of injury. Addition of the one-legged hop, Lachman, anterior drawer, and varus stress tests accounted for an additional 40% of the variability of function. When pain and giving way were added to the model, 79% of the variability was explained.

Activities of Daily Living↗
PubMed2001

A comparison of a modified Oswestry Low Back Pain Disability Questionnaire and the Quebec Back Pain Disability Scale.

BACKGROUND AND PURPOSE: The quality of a disability scale should dictate when it is used. The purposes of this study were to examine the validity of a global rating of change as a reflection of meaningful change in patient status and to compare the measurement properties of a modified Oswestry Low Back Pain Disability Questionnaire (OSW) and the Quebec Back Pain Disability Scale (QUE). SUBJECTS: Sixty-seven patients with acute, work-related low back pain referred for physical therapy participated in the study. METHODS: The 2 scales were administered initially and after 4 weeks of physical therapy. The Physical Impairment Index, a measure of physical impairment due to low back pain, was measured initially and after 2 and 4 weeks. A global rating of change survey instrument was completed by each subject after 4 weeks. RESULTS: An interaction existed between patients defined as improved or stable based on the global rating using a 2-way analysis of variance for repeated measures on the impairment index. The modified OSW showed higher levels of test-retest reliability and responsiveness compared with the QUE. The minimum clinically important difference, defined as the amount of change that best distinguishes between patients who have improved and those remaining stable, was approximately 6 points for the modified OSW and approximately 15 points for the QUE. CONCLUSION AND DISCUSSION: The construct validity of the global rating of change was supported by the stability of the Physical Impairment Index across the study period in patients defined as stable by the global rating and by the decrease in physical impairment across the study period in patients defined as improved by the global rating. The modified OSW demonstrated superior measurement properties compared with the QUE.

Activities of Daily Living↗
PubMed2000

Biomechanical considerations for rehabilitation of the knee.

Knowledge of the anatomy and biomechanics of the knee is critical for successful rehabilitation following knee injury and/or surgery. Biomechanics of both the tibiofemoral and patellofemoral joints must be considered. The purpose of this paper is to provide a framework for rehabilitation of the knee by reviewing the biomechanics of the tibiofemoral and patellofemoral joints. This will include discussion of the relevant arthrokinematics as well as the effects of open and closed chain exercises. The implications for rehabilitation of the knee will be highlighted.

Biomechanical Phenomena↗
PubMed2000

Rehabilitation of the multiple-ligament-injured knee.

Rehabilitation for a patient with a multiple-ligament knee injury should be designed to reduce pain and swelling, restore range of motion, strength, and endurance, and to enhance proprioception, and dynamic stability of the knee, with the goals of restoring function and minimizing disability. The biomechanics of the knee must be considered when designing a rehabilitation program. General guidelines for rehabilitation of the multiple-ligament-injured knee include considerations for promoting tissue healing, decreasing pain and swelling, restoring full motion, increasing muscular strength and endurance, improving proprioception, enhancing dynamic stability of the knee, and reducing functional limitations and disability. A patient's progression through this sequence must be individualized and depends on the pattern of ligament injury or surgical procedure that was performed, and the principles of tissue healing. Specific guidelines for rehabilitation following ACL reconstruction combined with MCL repair, PCL reconstruction, combined ACL-PCL reconstruction, and reconstruction of the LCL and posterolateral corner have been provided.

Activities of Daily Living↗
PubMed1998

Use of the International Knee Documentation Committee guidelines to assess outcome following anterior cruciate ligament reconstruction.

The purpose of this project was to determine if guidelines established by the International Knee Documentation Committee (IKDC) could distinguish differences in outcome, as indicated by the patients' subjective rating of knee function following ACL reconstruction, and to determine if all subgroups included in the IKDC rating system contribute to the prediction of the overall final IKDC rating. A total of 133 patients undergoing ACL reconstruction were evaluated according to IKDC guidelines 1-5 years postoperatively. Each subject was rated in each of four subgroups on the IKDC scale: patient subjective assessment, symptoms, range of motion (ROM), and laxity. The worst rating for the subgroups defined the overall final rating. The outcome from the patient's perspective was determined by asking them to rate the function of their knee on a scale from 0 to 100 with 100 being the level of function before injury. Average length of follow-up was 3.2 years (range 1.1-6.3 years). ANOVA indicated that the patients' subjective rating of knee function on a scale from 0 to 100 differed according to the overall final IKDC rating (F = 16.1, P < 0.001). The average subjective rating of knee function for those with a normal IKDC rating was 95.2, nearly normal was 91.2, abnormal was 84.9, and severely abnormal was 75.4. The average subjective rating of knee function for those who were severely abnormal was significantly different from those rated normal, nearly normal, and abnormal, and the average subjective rating for those who were abnormal was significantly different from those who were normal or nearly normal. There was no significant difference in average subjective rating between those who were rated as normal or nearly normal. Regression analysis indicated that all four subgroups contributed significantly to the prediction of the final IKDC rating (r2 = 0.70), but the majority of the variance (62%) was accounted for by symptoms and laxity. These results appear to indicate that the IKDC guidelines are useful for describing the outcome following ACL reconstruction. Further testing of the IKDC guidelines is necessary to determine if they are capable of detecting a change in the patients over time following treatment and/or surgery of the knee.

Adolescent↗
PubMed1998

Development of a patient-reported measure of function of the knee.

The purpose of the present study was to demonstrate the reliability, validity, and responsiveness of the Activities of Daily Living Scale of the Knee Outcome Survey, a patient-reported measure of functional limitations imposed by pathological disorders and impairments of the knee during activities of daily living. The study comprised 397 patients; 213 were male, 156 were female, and the gender was not recorded for the remaining twenty-eight. The mean age of the patients was 33.3 years (range, twelve to seventy-six years). The patients were referred to physical therapy because of a wide variety of disorders of the knee, including ligamentous and meniscal injuries, patellofemoral pain, and osteoarthrosis. The Activities of Daily Living Scale was administered four times during an eight-week period: at the time of the initial evaluation and after one, four, and eight weeks of therapy. Concurrent measures of function included the Lysholm Knee Scale and several global measures of function. The subjects also provided an assessment of the change in function, with responses ranging from greatly worse to greatly better, at one, four, and eight weeks. The Activities of Daily Living Scale was administered to an additional sample of fifty-two patients (thirty-two male and twenty female patients with a mean age of 31.6 years [range, fourteen to sixty-six years]) before and after treatment within a single day to establish test-retest reliability. Factor analysis revealed two dominant factors: one that reflected a combination of symptoms and functional limitations and the other, only symptoms. The internal consistency of the Activities of Daily Living Scale was substantially higher than that of the Lysholm Knee Scale (coefficient alpha, 0.92 to 0.93 compared with 0.60 to 0.73), resulting in a smaller standard error of measurement for the former scale. Validity was demonstrated by moderately strong correlations with concurrent measures of function, including the Lysholm Knee Scale (r = 0.78 to 0.86) and the global assessment of function as measured on a scale ranging from 0 to 100 points (r = 0.66 to 0.75). Analysis of variance with repeated measures revealed significant improvements in the score on the Activities of Daily Living Scale during the eight weeks of physical therapy (F2,236 = 108.13; p < 0.0001); post hoc testing indicated that the change in the score at eight weeks was significantly greater than the change at four weeks and that the change at four weeks was significantly greater than that at one week (p < 0.0001 for both). As had been hypothesized, the patients in whom the knee had somewhat improved had a significantly smaller change in the score, both at four weeks (F1,189 = 33.50; p < 0.001) and at eight weeks (F1,156 = 22.48; p < 0.001), compared with those in whom the knee had greatly improved. The test-retest reliability coefficient (intraclass correlation coefficient[2,1]) was 0.97. These results suggest that the Activities of Daily Living Scale is a reliable, valid, and responsive instrument for the assessment of functional limitations that result from a wide variety of pathological disorders and impairments of the knee.

Activities of Daily Living↗
PubMed1998

An electromyographic study of vastus medialis oblique and vastus lateralis activity while ascending and descending steps.

Imbalances in the firing pattern and contraction intensity of the vastus medialis oblique (VMO) and the vastus lateralis (VL) have been considered important factors contributing to patellofemoral joint dysfunction. Vastus medialis oblique and vastus lateralis electromyographic (EMG) activity were measured for 15 individuals without patellofemoral pain (asymptomatic group) and 13 subjects with patellofemoral pain (symptomatic group) while ascending and descending steps. The peak VMO/VL ratios of EMG activity and the difference in peak VMO and VL onset times were measured. Two-way mixed-model analyses of variance (ANOVA) were used to determine the main effects of group (asymptomatic and symptomatic), phase (concentric phase ascending and two eccentric phases descending stairs), and the interaction between group and phase. The ANOVAs indicated no difference between groups for the peak VMO/VL EMG ratio or for the onset timing between peak VMO and VL muscle activity. Combining groups, the peak VMO/VL EMG ratio was less for the eccentric weight acceptance phase of descent compared with the concentric phase of ascent. These findings suggest no differences between asymptomatic and symptomatic individuals, but differences may exist between concentric and eccentric VMO/VL ratios. Further research is needed to determine if VMO and VL muscle imbalances contribute to patellofemoral dysfunction.

Adolescent↗
PubMed1998

Rehabilitation following surgical procedures to address articular cartilage lesions in the knee.

Knowledge of the structure and function of articular cartilage is important when considering rehabilitation following surgical procedures for articular cartilage lesions of the knee. Articular cartilage is avascular and derives its nutrition primarily from synovial fluid, resulting in a limited potential for regeneration. Basic science evidence has demonstrated that compressive loading may have a positive impact on articular cartilage healing; however, excessive shear loading may be detrimental. Rehabilitation following surgical procedures for articular cartilage lesions should include controlled range of motion exercises. Exercises to enhance muscle function must be done in a manner which minimizes shear loading of the joint surfaces in the area of the lesion. A period of protected weight bearing is often necessary and should be followed by progressive loading of the joint. This article will: 1) provide a brief review of the structure and function of articular cartilage lesions as it relates to rehabilitation; 2) describe common surgical procedures to address articular cartilage lesions; and 3) provide guidelines for rehabilitation following surgical management of articular cartilage lesions.

Animals↗
PubMed1998

Comparison of performance-based and patient-reported measures of function in anterior-cruciate-ligament-deficient individuals.

There is a dearth of reliable and valid instrumentation that measures disability following injury and/or surgery of the knee joint that is responsive to clinically significant changes over time. The purpose of this investigation was to determine whether performance-based or patient-reported measures of function are more effective in estimating disability in individuals with an anterior-cruciate-ligament (ACL)-deficient knee. Subjective rating of knee function was used as the criterion measure for disability, and selected performance-based and patient-reported measures were used as estimation variables. Twenty-nine individuals with an ACL-deficient knee participated in this investigation. Step-wise regression analysis revealed that the Cincinnati Knee Scale, Lysholm Knee Scale, and hop index were the most effective estimates of disability. The results demonstrate that patient-reported measures are more related to the patient's level of disability in individuals with an ACL-deficient knee. More research is necessary to substantiate these findings.

Adolescent↗
PubMed1997

Electromyographic analysis of the squat performed in self-selected lower extremity neutral rotation and 30 degrees of lower extremity turn-out from the self-selected neutral position.

Little research is available on the muscle activity patterns of the lower extremity muscles during dynamic closed chain squatting activities. The purpose of this study was to examine the effect of lower extremity position during an Olympic squat on the muscle activity patterns of the vastus medialis, vastus lateralis, semimembranosus/semitendinosus, and biceps femoris. Twenty-five healthy, untrained subjects, 18-35 years old, were randomly assigned initial squatting positions of either self-selected neutral or 30 degrees of lower extremity turn-out from the self-selected neutral position. Surface electromyography and motion analysis data were collected simultaneously in 10 degrees intervals and analyzed from 10-60 degrees of knee flexion in both the ascending and descending phases of the squat. A four-way analysis of variance indicated that the main effect of lower extremity position and the interaction of extremity position and knee joint angles were not found to cause significant changes in muscle activity patterns. Significant changes in muscle activity did occur with changes in knee flexion angles in the vastus medialis and vastus lateralis but not in the semimembranosus/semitendinosus or biceps femoris.

Adolescent↗
PubMed1996

Allograft versus autograft anterior cruciate ligament reconstruction: 3- to 5-year outcome.

Sixty-four patients whose knees underwent anterior cruciate ligament reconstruction with nonirradiated allograft tissue were compared with 26 patients whose anterior cruciate ligaments were reconstructed using autograft tissue 3 to 5 years after their operation. Detailed symptoms, activity-level, and functional outcomes, physical examination, and instrumented knee testing were recorded. No statistically significant differences were found except a higher incidence of loss of terminal extension in the autograft group. These differences were small and not considered clinically significant. Laxity and knee scores were similar in both groups. According to International Knee Documentation Committee ratings, overall outcome was normal or nearly normal in 48% of the allograft patients and in 38% of the autograft patients. Overall subjective rating with the Cincinnati Knee Score was 85.8 for the allograft patients and 84.5 for the autograft patients. Allograft tissue provides an acceptable alternative to autograft tissue for reconstruction of the anterior cruciate ligament.

Adult↗
PubMed1996

Revision anterior cruciate ligament surgery: experience from Pittsburgh.

Twenty-five patients who underwent revision anterior cruciate ligament reconstruction after failure of a previous intraarticular reconstruction were retrospectively reviewed. Before revision, all patients reported functional instability with sports or activities of daily living and exhibited increased anterior patholaxity on physical examination. Fresh frozen irradiated allograft tissue was used for all revisions. A comprehensive knee analysis using a subjective and objective system was done for all patients preoperatively and at the time of final followup. The mean age at revision surgery was 25 years and average time from primary to revision surgery was 30 months. Average length of followup was 28 months. The anteroposterior displacement was improved in all patients. Sixty-four percent of patients had less than 5 mm side to side difference on arthrometric testing. Eighty percent had either a Grade 0 or Grade 1 pivot shift. The average modified Cincinnati Knee Score was 68 with the results of 88% of patients rated abnormal by International Knee Documentation Committee guidelines. Seventy-six percent of patients were satisfied with their results and would elect to have revision surgery again. These results show that patients having revision anterior cruciate ligament reconstruction for a failed intraarticular reconstruction had improvement in their functional status compared with prerevision; however, they did not achieve the same level of satisfactory results as primary anterior cruciate ligament reconstruction.

Activities of Daily Living↗
PubMed1996

Rehabilitation following allograft meniscal transplantation: a review of the literature and case study.

Treatment of meniscal injuries in the knee has evolved over the past three decades. New research regarding the functional roles of the menisci has increased emphasis on the preservation of meniscal tissue. Meniscal transplantation has developed as a surgical technique for individuals whose menisci have been compromised through trauma or previous meniscectomy. The purpose of this article is to review the current literature regarding meniscal function, the deleterious effects of meniscectomy, and the development of transplantation of allograft menisci as a surgical technique. A case study of a 28-year-old male undergoing medial meniscus transplantation is presented, with emphasis on the development of postoperative rehabilitation guidelines.

Adult↗
PubMed1995

Loss of motion following knee ligament reconstruction.

Loss of motion following knee ligament surgery is a common and potentially serious complication. Loss of extension is most common following anterior cruciate ligament reconstruction, and loss of flexion is most common after posterior cruciate ligament reconstruction. The aetiology of loss of motion is multifactorial and includes impingement and capsulitis. The risk for loss of motion can be minimised by appropriate preoperative, intraoperative and postoperative intervention. Management of loss of motion depends on the cause and length of time following surgery.

Anterior Cruciate Ligament↗