Biomedical subjects

J R Steadman

Publications and source records attributed to J R Steadman.

At least 19 recordsLinked to original sources

PubMed2001

The role of capsular distention in the arthroscopic management of arthrofibrosis of the knee: A technical consideration.

Arthroscopic treatment of arthrofibrosis of the knee is a technically challenging procedure. Capsular distention with fluid before arthroscopy results in easier and safer insertion of arthroscopic instruments with improved arthroscopic visualization. In addition, it stretches the entire capsule, including the difficult to access posterior capsule. This report describes a simple technique for capsular distention before arthroscopic treatment of arthrofibrosis of the knee.

Arthroscopy↗

PubMed2001

Microfracture: surgical technique and rehabilitation to treat chondral defects.

Full-thickness articular cartilage defects rarely heal spontaneously. Some patients may not have clinically significant problems from chondral defects, but most eventually have degenerative changes. Techniques to treat chondral defects include abrasion, drilling, autografts, allografts, and cell transplantation. The senior author (JRS) developed the microfracture technique to enhance chondral resurfacing by providing a suitable environment for new tissue formation and taking advantage of the body's own healing potential. Microfracture has been done in more than 1800 patients. Specially designed awls are used to make multiple perforations, or microfractures, into the subchondral bone plate. Perforations are made as close together as possible, but not so close that one breaks into another. They usually are approximately 3 to 4 mm apart. The integrity of the subchondral bone plate must be maintained. The released marrow elements (including mesenchymal stem cells, growth factors, and other healing proteins) form a surgically induced super clot that provides an enriched environment for new tissue formation. The rehabilitation program is crucial to optimize the results of the surgery. It promotes the ideal physical environment for the marrow mesenchymal stem cells to differentiate into articular cartilagelike cells, ultimately leading to development of a durable repair cartilage that fills the original defect.

Cartilage, Articular↗

PubMed2001

Effects of walking poles on lower extremity gait mechanics.

PURPOSE: The purpose of this study was to determine whether walking with poles reduces loading to the lower extremity during level over ground walking. METHODS: Three-dimensional gait analysis was conducted on 13 healthy adults who completed 10 walking trials using three different poling conditions (selected poles, poles back, and poles front) and without the use of poles (no poles). The inverse dynamics approach was used to calculate kinetic data via anthropometric, kinematic, and kinetic data. RESULTS: All walking with poles conditions increased walking speed (P = 0.0001-0.0004), stride length (P < 0.0001), and stance time (P < 0.0001) compared with the no poles condition. There also was a decrease in anterior-posterior GRF braking impulse (P = 0.0001), a decrease in average vertical GRF walking with poles (P < 0.0001-0.0023), and a decrease in vertical (compressive) knee joint reaction force (P < 0.0001-0.0041) compared with the no poles condition. At the knee, extensor impulse decreased a 7.3% between the no poles and selected poles conditions (P = 0.0083-0.0287) and 10.4% between the no poles and poles back conditions (P < 0.0001). The support moment was reduced between the no poles and poles back (P = 0.0197) and poles front (P = 0.0002) conditions. Ankle plantarflexor work (A2) was reduced in the poles-front condition (P = 0.0334), but no differences were detected in all other ankle, knee or hip power and work variables (P > 0.05). CONCLUSION: There were differences in kinetic variables between walking with and without poles. The use of walking poles enabled subjects to walk at a faster speed with reduced vertical ground reaction forces, vertical knee joint reaction forces, and reduction in the knee extensor angular impulse and support moment, depending on the poling condition used.

Adult↗

PubMed2000

Intra-articular knee joint effusion induces quadriceps avoidance gait patterns.

OBJECTIVES: (1) To identify adaptations caused by intra-articular knee joint effusion during walking and (2) to determine if knee joint effusion may be a causative factor in promoting quadriceps avoidance gait patterns. DESIGN: Gait testing of 14 healthy individuals who underwent incremental saline injections of the knee joint capsule.Background. Gait adaptations have been reported in the literature for knee injured and rehabilitating individuals. Knee joint capsular afferent activity can influence knee joint function. METHODS: Gait analysis was employed in a pre- and post-test, repeated measures design to determine lower extremity joint kinematics, kinetics, energetics and thigh EMG adaptations due to intra-articular knee joint effusion. RESULTS: Knee effusion caused an increase in hip and knee flexion through the stance phase. Knee extensor torque, impulse and negative and positive work were diminished with increased effusion levels. Quadriceps activity decreased and hamstring activity increased due to intra-articular knee joint effusion. DISCUSSION: These adaptations cannot be attributed to an injury, surgery or rehabilitation. Thus, the results of this experiment suggest knee joint capsular distention, via knee joint effusion, may be responsible for many gait adaptations reported for knee injured individuals in previous investigations. CONCLUSIONS: Knee joint effusion and the subsequent capsular distention can cause major alterations in the normal gait cycle and can be considered a causative factor promoting the acquisition of quadriceps avoidance gait patterns. RELEVANCE: This study provides reference data on the effects of intra-articular knee joint effusion on gait parameters by which future studies of injured or rehabilitating individuals can be compared.

Adaptation, Physiological↗

PubMed1999

[The microfracture technic in the management of complete cartilage defects in the knee joint].

Full thickness defects of the articular cartilage rarely heal spontaneously. While some patients do not develop clinically significant problems from chondral defects, most eventually develop degenerative changes associated with the cartilage damage over time. Techniques to treat chondral defects include abrasion, drilling, tissue autografts, allografts, and cell transplantation. The senior author has developed a procedure referred to as the "microfracture." This technique enhances chondral resurfacing by providing a suitable environment for tissue regeneration and by taking advantage of the body's own healing potential. This technique has now been used in more than 1400 patients. Specially designed awls are used to make multiple perforations, or "microfractures", into the subchondral bone plate. The perforations are made as close together as necessary, but not so close that one breaks into another. Consequently, the microfracture holes are approximately three to four millimeters apart (or 3 to 4 holes per square centimeter). Importantly, the integrity of the subchondral bone plate is maintained. The released marrow elements form a "super clot" which provides an enriched environment for tissue regeneration. Follow up with long term results of more than 8 years have been positive and very encouraging.

Bone Regeneration↗

PubMed1999

A clinical study of collagen meniscus implants to restore the injured meniscus.

The meniscus performs critical functions within the knee, and its loss frequently leads to osteoarthritis and irreversible joint damage. Because prosthetic replacement of the meniscus has proven ineffective, the authors used tissue engineering techniques to develop a resorbable collagen scaffold (collagen meniscus implant) that supports ingrowth of new tissue and eventual regeneration of the lost meniscus. Eight patients underwent arthroscopic placement the collagen meniscus implant to reconstruct and restore the irreparably damaged medial meniscus of one knee. Seven patients had one or more prior meniscectomies, and one patient had an acute meniscus injury. Patients were observed with frequent clinical, serologic, radiographic, and magnetic resonance imaging examinations for at least 24 months (range, 24-32 months). All patients underwent relook arthroscopy and biopsy of the implant regenerated tissue at either 6 or 12 months after implantation. All patients improved clinically from preoperatively to 1 and 2 years postoperatively based on pain, Lysholm scores, Tegner activity scale, and self assessment. Relook arthroscopy revealed tissue regeneration in all patients with apparent preservation of the joint surfaces based on visual observations. Histologic analysis confirmed new fibrocartilage matrix formation. Radiographs confirmed no progression of degenerative joint disease. The collagen meniscus implant is implantable, biocompatible, resorbable, and supports new tissue regeneration as it is resorbed. This tissue seems to function similar to meniscus tissue by protecting the chondral surfaces.

Arthroscopy↗

PubMed1999

Lower limb stability with ACL impairment.

STUDY DESIGN: Repeated measures (3 separate day sessions) to determine test reliability; single-session repeated measures to compare stability between limbs. OBJECTIVES: To develop a functional test measuring dynamic stability that is capable of differentiating between the injured and uninjured lower limb in 2 populations: (1) people with anterior cruciate ligament deficiency (ACLd) and (2) people with anterior cruciate ligament reconstruction (ACLr), and to establish the reliability of this test. BACKGROUND: Many functional tests of the lower limb used by clinicians, such as the 1-legged hop for distance, the 1-legged hop for time, the vertical jump, the triple hop for distance, shuttle run, and single-limb standing, do not allow the clinician to discern differences between function in the injured and uninjured limbs. METHODS AND MEASURES: Twenty-five nonimpaired subjects (14 men, 11 women, aged 31.2 +/- 9.1 years), 11 subjects with ACLr (9 men, 2 women, aged 26.3 +/- 10.4 years), and 13 subjects with ACLd (5 men, 8 women, aged 40.4 +/- 12.6 years) were tested. Twelve nonimpaired subjects participated in 3 testing sessions to determine the reliability of the force plate measures. Ground reaction forces (vertical, medial-lateral, and anterior-posterior) were measured while the subjects performed 1-legged hop and step-down tests onto a force plate. Stability was defined as the ability to transfer the vertical projection of the center of gravity to the supporting base and keep the knee still. A repeated-measures analysis of variance (2-factor; limbs by trials) was used to compare the stability between limbs. RESULTS: The majority of the measures used to calculate dynamic stability were reliable. Moreover, the data provide normal standards of functional knee stability for step-down and hop tests. In the step-down test, changes in vertical force did identify dysfunction in the injured limb (stabilization time = 1527 +/- 216 ms) compared to the uninjured limb (stabilization time = 892 +/- 498 ms) for subjects with ACLr. CONCLUSIONS: The normal standards may serve as a reference for comparing functional differences in ACLr or ACLd populations. The vertical force parameter during a step-down may be useful as an outcome measure to monitor progress during rehabilitation.

Adolescent↗

PubMed1999

MR imaging of knee anterior cruciate ligament and associated injuries in skiers.

Tears of the ACL have become widespread in the skiing population. Understanding of the mechanisms and patterns of associated injury of such ACL tears has benefited from and contributed greatly to clinical and imaging evaluation and management. MR imaging of the injured knee has become the gold standard comprehensive imaging examination for evaluating the ACL tear and associated soft-tissue and osseous injuries and assisting the treating physician in planning management, as the isolated ACL tear has proven to be the exception rather than the rule in skiing knee injuries.

Anterior Cruciate Ligament Injuries↗

PubMed1999

Role of MR imaging in sports medicine research. Basic science and clinical research studies.

The advent and advancement of MR imaging have provided an entire new dimension for medical imaging. MR imaging has been especially useful because of its capacity to image nonmineralized tissues with a very high degree of resolution. Although modalities such as ultrasound and scintigraphy have proven useful for specific purposes, it is MR imaging that has the most utility and capabilities, especially in the area of sports-induced injuries. The technology associated with MR imaging has expanded greatly, and it continues to evolve at a rapid pace. The result has been an ever-increasing diagnostic capability that has become more economic with time. As described previously, MR imaging is gaining importance in the area of comparative medicine for animal athletes as well. It is also interesting to note that MR imaging now has a greater potential for monitoring physiological and biochemical changes as well as anatomic ones. Some newer MR units actually include physiologic data acquisition components. Consequently, new bioassays and nondestructive tissue tests can be performed to further understand the molecular biology and ongoing cellular processes in any given condition. Coupled with MR spectroscopy, the enhanced MR techniques should continue to contribute to the overall information that will be integrated into the training and rehabilitation of patients with sports-induced inflammation and injuries. The authors support and encourage ongoing efforts in the area of MR imaging research, both basic science and clinical studies.

Animals↗

PubMed1998

Reconstruction of the anterior cruciate ligament in patients who are at least forty years old. A long-term follow-up and outcome study.

The long-term results were reviewed for seventy-two patients (seventy-five knees) who had had a bone-patellar ligament-bone intra-articular reconstruction of the anterior cruciate ligament between August 1984 and May 1992. The mean age of the patients at the time of the operation was forty-five years (range, forty to sixty years). Three patients had a bilateral procedure. The primary mechanisms of injury were accidents that occurred during skiing (thirty-two knees), tennis (fourteen knees), and soccer (five knees). We analyzed the responses to subjective questionnaires, the functional results, and the objective clinical data. The clinical examination included assessment of the range of motion, performance of Lachman and pivot-shift tests, and measurements with use of a KT-1000 arthrometer. All knees were evaluated with use of three common rating scales: that of Lysholm and Gillquist; that of The Hospital for Special Surgery, as modified by Insall et al.; and the International Knee Ligament Standard Evaluation Form. At the latest follow-up evaluation, at a mean of fifty-five months (range, twenty-six to 117 months), three patients reported pain or swelling. No patient reported giving-way or symptoms related to the patellofemoral joint. The mean range of extension was -12 to 6 degrees, compared with -8 to 42 degrees preoperatively, and the mean range of flexion was 112 to 150 degrees, compared with 52 to 154 degrees preoperatively. Flexion was limited to 112 degrees in one patient, but this was 5 degrees greater than that of the uninvolved knee. Sixty knees (80 per cent) had a negative pivot-shift test, and ten knees (13 per cent) had a grade of 1+. On testing with the KT-1000 device at maximum manual pressure, the mean difference between the injured and uninjured knees was found to have improved by 5.1 millimeters, from 6.4 millimeters preoperatively to 1.4 millimeters postoperatively (p < 0.01). The grade on the International Knee Ligament Standard Evaluation Form improved markedly; seventy-two knees (96 per cent) had a grade of C or D preoperatively, whereas seventy knees (93 per cent) had a grade of A or B postoperatively. The Hospital for Special Surgery score improved from a mean of 69 points preoperatively to a mean of 92 points postoperatively (p < 0.01). The mean score according to the scale of Lysholm and Gillquist increased from a mean of 63 points preoperatively to a mean of 94 points postoperatively (p < 0.01). All patients indicated that they were pleased with the result of the procedure. Bicycling was resumed at a mean of four months; jogging, at a mean of nine months; skiing, at a mean of ten months; and tennis, at a mean of twelve months.

Adult↗

PubMed1998

Quantification of elastic resistance knee rehabilitation exercises.

Elastic resistance exercises are frequently used for knee rehabilitation following injury and/or surgery. The evidence supporting this mode of rehabilitation is primarily anecdotal, and no biomechanical assessment of elastic resistance exercises has been previously published. The purpose of this project was to quantify muscle activation levels, knee joint angles, and applied force during five rehabilitation exercises utilizing an elastic resistance device. Twelve subjects with no previous knee injury performed double knee dip, hamstring pull, leg press, single knee dip, and side-to-side jump exercises while sagittal plane kinematics, applied force from the elastic resistance device, and electromyographic activity of eight lower extremity muscles were collected. The muscle activation patterns suggest a progressive continuum of rehabilitation exercises that can be applied to nonoperative injuries as well as anterior cruciate ligament reconstructions.

Adult↗

PubMed1998

Treatment of articular cartilage defects in athletes: an analysis of functional outcome and lesion appearance.

This article characterizes chondral injuries and reviews the results of microfracture treatment in high-level competitive and recreational athletes. Thirty-eight high-level and 140 recreational athletes completed functional questionnaires preoperatively and yearly postoperatively, recording symptoms, function, and activity level. Second-look arthroscopy tapes were available in 26 high-level and 54 recreational athletes. The mean follow-up for the high-level athletes was 3.7 +/- 1.4 years. Chondral defects averaged 223 +/- 180 mm2. Lesion size and follow-up were not significantly different in the recreational group. Functional questionnaire responses demonstrated significant improvements from the time of microfracture to final follow-up. Improvement in function and symptoms was similar for the competitive and recreational athletes.

Adolescent↗

PubMed1997

Muscle activity in wedge, parallel, and giant slalom skiing.

Muscle activity patterns of six alpine skiers were compared during nine runs each of wedge (W), short radius parallel (P), and giant slalom (GS) turns. Bipolar surface electrodes were placed over 12 muscles on the right side of the body: anterior tibialis, medial gastrocnemius, vastus medialis, vastus lateralis, rectus femoris, medial hamstrings, biceps femoris, gluteus maximus, adductors, rectus abdominis, external obliques, and erector spinae. Repeated measures ANOVA was used to test for differences in average and peak EMG amplitudes between W, P, and GS (P < 0.1). Average amplitude was significantly different between all turning styles (W < P < GS) for four muscles (vastus lateralis, medial hamstrings, biceps femoris, and external obliques) and significantly less for W versus P or GS for four muscles (anterior tibialis, vastus medialis, rectus femoris, and rectus abdominis). The gluteus maximus was the only muscle that had significantly greater activity in W than P. Average amplitude was greater than 50% MVC for the vastus medialis, vastus lateralis, biceps femoris, gluteus maximus, and adductors in all conditions; and for the anterior tibialis, medial hamstrings, and rectus femoris in GS and P; and for the medial gastrocnemius and erector spinae in GS. Peak amplitude was greater than 150% maximal voluntary contraction (MVC) for the vastus medialis, vastus lateralis, biceps femoris, gluteus maximus, and adductors in all conditions, and for the medial gastrocnemius, rectus femoris, and erector spinae in GS. This research indicates that with the exception of the gluteus maximus, greater muscle activity is required in GS followed by P and W turns.

Adult↗

PubMed1997

Regeneration of meniscal cartilage with use of a collagen scaffold. Analysis of preliminary data.

A collagen scaffold was designed for use as a template for the regeneration of meniscal cartilage and was tested in ten patients in an initial, Food and Drug Administration-approved, clinical feasibility trial. The goal of the study was to evaluate the implantability and safety of the scaffold as well as its ability to support tissue ingrowth. The study was based on the findings of in vitro and in vivo investigations in dogs that had demonstrated cellular ingrowth and tissue regeneration through the scaffold. Nine patients remained in the study for at least thirty-six months, and one patient voluntarily withdrew after three months for personal reasons. The collagen scaffold was found to be implantable and to be safe over the three-year period. Histologically, it supported regeneration of tissue in meniscal defects of various sizes. No adverse immunological reactions were noted on sequential serological testing. On second-look arthroscopy, performed either three or six months after implantation, gross and histological evaluation revealed newly formed tissue replacing the implant as it was resorbed. At thirty-six months, the nine patients reported a decrease in the symptoms. According to a scale that assigned 1 point for strenuous activity and 5 points for an inability to perform sports activity, the average score was 1.5 points before the injury, 3.0 points after the injury and before the operation, and 2.4 points at six months postoperatively, 2.2 points at twelve months, 2.0 points at twenty-four months, and 1.9 points at thirty-six months. According to a scale that assigned 0 points for no pain and 3 points for severe pain, the average pain score was 2.2 points preoperatively and 0.6 point thirty-six months postoperatively. One patient, who had had a repair of a bucket-handle tear of the medial meniscus and augmentation with the collagen scaffold, had retearing of the cartilage nineteen months after implantation. Another patient had debridement because of an irregular area of regeneration at the scaffold-meniscus interface twenty-one months after implantation. Magnetic resonance imaging scans demonstrated progressive maturation of the signal within the regenerated meniscus at three, six, twelve, and thirty-six months. These findings suggest that regeneration of meniscal cartilage through a collagen scaffold is possible. Additional studies are needed to determine long-term efficacy.

Adult↗

PubMed1996

Revision of failed prosthetic anterior cruciate ligament reconstruction.

Revision of failed prosthetic anterior cruciate ligament reconstructions will continue to be necessary as previously placed prosthetic devices fail with time. These patients often present with recurrent instability, pain, swelling, or effusions. Graft rupture and the generation of particulate debris are common causes of these symptoms. To effectively treat these patients requires careful preoperative evaluation and planning. Operative treatment includes removing the prosthesis and metal fixation devices, evaluating femoral and tibial bone stock, and determining adequacy of previous tunnel position. Staging of the operation may be a necessity if significant bone loss or poor tunnel position on either the femoral or tibial side requires bone grafting. The use of an autogenous bone-patellar tendon-bone graft is suggested and has proven to be effective in restoring knee stability in these revision cases. The ultimate outcome following revision of failed prosthetic ligaments may be limited by associated intraarticular pathology often seen in this patient population.

Anterior Cruciate Ligament↗

PubMed1996

Electromyographic and kinematic analysis of graded treadmill walking and the implications for knee rehabilitation.

Muscle activity, joints, angles, and heart rate during uphill walking were compared for application in knee rehabilitation. The objectives of this study were to quantify muscle activation levels at different treadmill grades and to determine the grade(s) at which knee range of motion would not further compromise the joint. Average and peak electromyographic activity of the quadriceps (vastus medialis oblique and vastus lateralis) and hamstrings (biceps femoris and medial hamstrings (semimembranosus/semitendinosus)] was recorded during walking at 0, 12, and 24% grade. Six subjects (age = 28.5 +/- 3.7 years, stature = 1.79 +/- .05 m, and mass = 74.7 +/- 7.9 kg) walked at self-selected speeds at each grade while ankle, knee and hip angles, heart rate, and electromyographic activity (surface electrodes) were recorded. Maximum voluntary contractions provided a relative reference for the electromyographic activity during walking. Average and peak electromyographic activity increased significantly across grades for the vastus medialis oblique (125 and 154%), vastus lateralis (109 and 139%), and biceps femoris (53 and 46%), but remained similar for the medial hamstrings. Maximum knee flexion at heel strike increased significantly with grade. Despite decreased self-selected speeds with increasing grade, there were significant increases in heart rate across grades. The results of this study provide a basic understanding of the quadriceps and hamstrings activity levels, lower extremity joint range of motion, and cardiovascular requirements of graded treadmill walking in normal subjects. The results also suggest that a grade just greater than 12% may be most beneficial for knee rehabilitation to minimize patellofemoral discomfort or potential strain on the anterior cruciate ligament. The benefits achieved through this functional activity encourage its implementation in rehabilitation and provide a basis for comparison with injured patients.

Adult↗

PubMed1995

Autogenous replacement of the meniscus cartilage: analysis of results and mechanisms of failure.

Autogenous replantation of meniscal cartilage (resection of 80% of the meniscus cartilage followed by immediate replantation) was performed in 14 dogs as a control arm of a meniscal replacement study. The purpose was to assess the ability of the excised tissue to heal to the intact rim and function as a meniscus cartilage. This procedure is an idealized model of allografting meniscus cartilage in that the tissue is fresh, autogenous, and perfectly sized. If this procedure did not succeed, it seemed likely to the authors that allografting meniscal cartilage would have diminished chances for success. Evaluation of these replant failures led us to speculate that the causes and mechanisms might include slow or incomplete revascularization, inadequate mechanical fixation or stabilization, and, perhaps, some type of rejection phenomenon not examined or confirmed in the present study. We believe these mechanisms will be particularly deleterious for allografted meniscal cartilages and recommend further extensive evaluation of meniscal allografts before wide clinical use.

Animals↗

PubMed1995

Muscle activity in slalom and giant slalom skiing.

The purpose of this study was to document and compare the muscular activity patterns observed in seven competitive racers during slalom (SL) and giant slalom (GS) skiing using quantitative parameters of EMG and qualitative video recordings. Twelve muscles of the leg and trunk were monitored using surface electrodes and telemetry. EMG activity was related to phases of movement determined from the video. SL was partitioned into two phases (initiation and turning) and a third phase (completion) was distinguished for GS. The majority of muscles were active at a moderate to high level for the whole turn, with average amplitudes (AA) between 58% and 112% maximum voluntary contraction. Large peak amplitudes (PA) were attributed to the substantial components of centrifugal and gravitational force that the skier must resist in the latter part of the turn. The similarity in muscle activity between SL and GS was surprising. The only significant differences were increases of 11.8% in AA for the AT in SL and 8.8% in PA for the EO in GS. There was ample evidence of co-contraction, suggesting a quasistatic component to skiing.

Abdominal Muscles↗