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Biomedical subjects

J R Steadman

Publications and source records attributed to J R Steadman.

At least 37 records · Page 2Linked to original sources
PubMed1995

The surgical treatment of knee injuries in skiers.

Although the overall skin injury incidence continues to decline, knee injuries requiring surgery remain extremely common. Emphasis is placed on the history of the skier's fall in making an accurate diagnosis. This injury pattern is then assessed with the skier's age and activity level in determining the most appropriate surgical procedure. The actual surgical intervention is just a portion of the rehabilitation process in returning a skier back to sport as quickly as possible. The most common injuries requiring surgical intervention include meniscal tears, osteochondral fractures, and ligament tears. Our indications and techniques are described. Early focus on postoperative range of motion is emphasized. Strengthening begins only when full, pain-free range of motion is obtained. Utilizing these principles, our goals have been to complete the rehabilitation process coexistent with healing of the injury.

Age Factors↗
PubMed1995

Effects of human knee synovial fluid on chondrogenesis in vitro.

To evaluate the healing environment of chondral defects, synovial fluid samples from knees of 25 patients with a traumatic chondral defect were evaluated. Effect of the synovial fluid on chondrogenesis was measured using a chick limb bud bioassay. Samples from 11 of 17 acutely injured knees stimulated chondrogenesis, samples from 4 were inhibitory, and samples from 2 showed no effect. Samples from six of eight chronically injured knees inhibited chondrogenesis; the other two samples stimulated chondrogenesis. The relationship between acute versus chronic injury and effect of synovial fluid on chondrogenesis was statistically significant. We conclude that synovial fluid contains factors that stimulate cartilage healing in the acute period following traumatic injury, but this effect can become inhibitory if the lesion is allowed to become chronic.

Adult↗
PubMed1993

Arthroscopic assessment of the posterior compartments of the knee via the intercondylar notch: the arthroscopist's field of view.

This study was undertaken to assess the adequacy of visualization, limits of arthroscopic field of view (FOV), and potential "blind spots" at the periphery of the meniscocapsular junction using standard arthroscopic instrumentation. Five human cadaveric knees were assessed arthroscopically via standard anteromedial and anterolateral portal. Access to the posterior compartments was obtained via the intercondylar notch. FOV was maximized with first a 30 degrees and then a 70 degrees arthroscope, and the farthest point of visualization was marked with a holmium:yttrium-aluminum-garnet (YAG) laser. FOV was calculated as a percentage of the total meniscocapsular periphery. For the lateral compartment, FOV averaged 100.2% with the 30 degrees versus 116.6% with the 70 degrees arthroscope. In all knees, the entire periphery of the lateral meniscocapsular junction could be visualized with the 30 degrees arthroscope anteriorly combined with the 70 degrees arthroscope posteriorly. Medially, FOV averaged 68.9% with a 30 degrees and 88.1% with a 70 degrees arthroscope. A "blind spot" was present in all knees, averaging 21.5% of the meniscocapsular periphery with a 30 degrees arthroscope anteriorly and a 70 degrees arthroscope posteriorly.

Arthroscopy↗
PubMed1993

Case report of a successful closed reduction without anesthesia.

Intraarticular dislocation of the patella is a rare clinical entity. Horizontal dislocation occurs when the patella rotates 90 degrees about its horizontal axis. Of the 33 previously reported cases, only six have been successfully reduced by closed manipulation. Furthermore, all previously successful closed reductions have required general anesthesia to accomplish the reduction. Intraarticular dislocation of the patella in a 24-year-old man was successfully reduced in a closed fashion without anesthesia.

Adult↗
PubMed1993

Role of primary anterior cruciate ligament repair with or without augmentation.

Primary ACL repair with or without extra-articular augmentation can be functionally and statically successful based on our experience in high-performance athletes. Proper surgical technique, appropriate rehabilitation, and excellent quality of the tissue being repaired are required to achieve these results. Several notable improvements in diagnostic imaging, physical examination, surgical technique, and rehabilitation protocol have led to excellent results. The notchplasty, multiple loop suture technique, and improved meniscal repair are key factors. Moreover, we believe that one of the prime enhancements is to provide the highly stable extra-articular lateral capsular ligament reconstruction described previously. Laboratory findings have shown that this procedure provides excellent support against anterior subluxation immediately after surgery. It appears that release of the iliotibial band tissue proximally prevents stretching and failure of this extra-articular procedure. Rehabilitation unquestionably is a critical factor in the success of this surgical procedure. Immediate motion and appropriate biomechanical stresses on the repaired ligament have proved compatible with good functional and objective results. Even though intra-articular reconstruction of the torn ACL continues to be considered the gold standard, we remain convinced that primary repair of the ACL with appropriate extra-articular augmentation should not be ruled out in many cases. This procedure clearly is a viable, successful, and acceptable alternative to intra-articular reconstruction in selected cases.

Anterior Cruciate Ligament↗
PubMed1991

Alpine skiing and the mature athlete.

Alpine skiing is a popular sport enjoyed by millions of Americans annually. As the average age of the world population increases, so does the average age of the skier. The ever-increasing older group of skiers adds a new dimension to both the prevention and treatment of ski injuries. Several injuries, if not unique to the older skier, are more common in this group, and familiarity with the causes, treatments, risks, and avoidance of these injuries is essential for proper treatment. It is possible that with proper education, prevention, and physical training, the incidence of these injuries can be decreased to the level of the general population, and skiing will not be more hazardous to the older athlete.

Aged↗
PubMed1990

Future directions. Collagen-based prostheses for meniscal regeneration.

Prosthetic meniscal replacement offers the ability to stabilize the meniscectomized knee and provide prophylaxis against early degenerative arthritis. Since prosthetic meniscal replacement may be performed in the setting of normal articular cartilage, a prosthesis will be required to match the exact joint configuration, induce the same lubricity, produce the same coefficient of friction, and absorb and dampen the same joint forces (without incurring significant creep or abrasion) as does the normal meniscus. This feat is currently beyond the capabilities of artificial materials alone. Alternatively, collagen-based prostheses acting as resorbable regeneration templates offer the possibility of inducing regrowth of new menisci. This paper presents a summary of hypotheses, considerations, and laboratory evidence for the use of collagen-based, resorbable matrices as regeneration templates.

Animals↗
PubMed1989

Rehabilitation of the knee.

Rehabilitation of the knee following injury or operative reconstruction and repair is vitally important to realizing optimal results, return to athletics, labor, and activities of daily living. Outlined in detail is a regimen of continuous passive motion, protected early weight bearing, co-contraction (EMS) of hamstring and quadriceps muscles for conditioning and analgesia (TENS), and functional concentric--eccentric loading of the knee musculature. A rationale based on an understanding of biologic rates of healing, fixation strength, ligament isometricity, and stress-induced healing is discussed.

Athletic Injuries↗
PubMed1988

Rehabilitation of the anterior cruciate ligament in the athlete.

Recent medical advances in diagnosis, surgical technique, bracing and postoperative rehabilitation have greatly improved subjective and objective results following anterior cruciate ligament surgery. A team approach involving patient, therapist, athletic trainer, and surgeon is vital to a successful outcome. Surgical rationale and postoperative rehabilitation should be based on sound scientific data, recognising the need for static and dynamic knee stability. The rehabilitation programme should incorporate principles which enhances the well-being of the musculoskeletal system, avoiding potential problems such as periarticular contractures, disuse atrophy, negative cartilage changes, and cardiopulmonary deconditioning. This article is an attempt to summarise the scientific data and principles, and describe a rehabilitation programme which adheres to the data and principles outlined.

Athletic Injuries↗
PubMed1987

Ligament and tendon oxygenation measurements using polarographic oxygen sensors.

This pilot study was designed to investigate a new flexible polarographic oxygen sensor for intraarticular oxygen tissue tension monitoring, as a first step in designing a combined simultaneous oxygen and perfusion monitor. The tendoachilles in the sheep provided the initial testing model, which was followed by in vivo testing in the human knee. In the animal model, the tendoachilles was perforated by a single needle through which the new flexible multichannel polarographic oxygen sensor probe was passed. Variations in blood and oxygen delivery to the hindlimb were then produced by tourniquet and fraction of inspired oxygen (FiO2) changes. The oxygen sensors appropriately recorded current variations proportional to the hypothesized oxygen delivery. In the human model, the anterior cruciate ligament (ACL) in five human knees was exposed during routine total knee replacement surgery and stripped of the fat pad and synovial attachments. The probe was inserted into the substance of the ligament from distal to proximal. Oxygen measurements were taken with the tourniquet elevated and then inflated, in an effort to evaluate the response of the oxygen sensors and to establish the degree of oxygenation that the bone blood supply provides to the ACL. In the sheep, 100% of the time (13 of 13 events), the current changed appropriately to a change in the FiO2. Ninety-four percent of the time (17 of 18 events), the current changed appropriately to a tourniquet change. In the human ACL, the probe was 83% sensitive (5 of 6 events) to a tourniquet change. The FiO2 changes were inconclusive owing to an insufficient amount of time allowed for tissue perfusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Achilles Tendon↗
PubMed1987

Training for Alpine skiing.

Skiing requires aerobic fitness. For aerobic conditioning, there must be significant elevation in heart rate during training. Although anaerobic training benefits physical fitness in general, skiing requires more aerobic than anaerobic conditioning. Strength, power, and endurance can be maintained through the use of concentric and eccentric contractions, using a variety of equipment and sports. Care should be taken to avoid injury to the patellofemoral joint during training. It is important to use specificity in choosing sports, as well as the exercise patterns in preseason training. If these principles are recognized in ski conditioning, a successful and effective training program will result.

Athletic Injuries↗
PubMed1985

Rehabilitation of the injured knee.

The basis of rehabilitation is to return the patient to the preinjury status. The physician must recognize that muscle is made up of both Type I and Type II fibers, Type I having endurance and Type II having speed capabilities. Immobilization for long periods of time is destructive to the ligaments, muscles, and cartilage of the affected area. Some immobilization is required, however, for the healing of tissues. The basis of any postinjury rehabilitation program should take into account that controlled motion can decrease the deleterious effect of immobilization. At the same time, it allows for healing. The ranges of motion that are allowed must be determined for each specific injury. An approach to determining the losses in the psychological and physiologic states of the patient is identified and recommendations for rehabilitation are given.

Exercise Therapy↗
PubMed1982

Rehabilitation of skiing injuries.

It is important to include psychological and physiologic rehabilitation in addition to rehabilitation of the injured area. Motion that does not stress repairs of either ligament or bone is not contraindicated. Exercises that aggravate patellofemoral problems should be modified to avoid areas in the range of motion that cause crepitance or pain. The use of modalities such as electrical stimulation is an important adjunct. Exercisers that allow speed work-out and isolate the muscle group are helpful but not mandatory. Manual resistance can parallel each type of machine exercise. Ligaments that have been repaired should be allowed to mature prior to allowing subluxing stresses. Before resumption of skiing, reactive exercises should be done.

Athletic Injuries↗
PubMed1975

Differential inhibition of sclerotial germination in Whetzelinia sclerotiorum.

A number of diverse compounds including divalent metal ions, simple sugars, and common counterions, buffers, and fungicides were surveyed in the laboratory with regard to ability to inhibit germination of field-collected sclerotia from Whetzelinia sclerotiorum. Many compounds were inhibitory and several were comparable in effectiveness to benomyl and other commercial fungicides. Different levels of a given inhibitor were needed to prevent stipe formation, apothecial formation or mycelial germination. Inhibition was not correlated with ionic strength or related to pH.

Ascomycota↗
PubMed1970

Abscisic Acid in tobacco plants: tentative identification and its relation to stunting induced by pseudomonas solanaccarum.

In tobacco plants inoculated with the wilt-inducing bacterium, Pseudomonas solanacearum, there was a correlation between decreased internode elongation, maximum multiplication of the bacterium, and an increase in the growth inhibitor content of stems 4 to 12 days after inoculation, as determined by a wheat coleoptile assay. Initial wilting of the upper leaves was also correlated with an increase in inhibitor content of these tissues.Application of either the partially purified inhibitor from tobacco or pure (+)-abscisic acid to roots, terminal buds, or petioles of tobacco plants caused a reduction of internode length which lasted from 8 to 10 days following a single treatment. Repeated treatment was necessary to obtain growth retardation over a longer period of time.The tobacco inhibitor was tentatively identified as abscisic acid, based on a comparison with authentic abscisic acid on paper, thin layer, column, and gas-liquid chromatography. On the basis of optical rotatory dispersion, circular dichroism, and ultraviolet spectra, the tobacco inhibitor was indistinguishable from abscisic acid. Increases in the inhibitor content of infected tissues are attributed primarily to abscisic acid although other substances, not separable from abscisic acid by the procedures used, could also play a role. The inhibitor was not found in P. solanacearum culture medium.

Journal Article↗
PubMedDate not supplied

Arthroscopic subchondral bone plate microfracture technique augments healing of large chondral defects in the radial carpal bone and medial femoral condyle of horses.

OBJECTIVE: To evaluate the effect of arthroscopic subchondral bone microfracture on healing of large chondral defects in horses. STUDY DESIGN: Short- (4 months) and long-term (12 months) in vivo experimental chondral defect model. ANIMALS: 10 horses, aged 2 to 5 years. METHODS: Each horse had a 1 cm2 full-thickness chondral defect created in both radial carpal bones and both medial femoral condyles. One carpus and one femoral condyle of each horse had the subchondral bone plate under the defect perforated using an orthopedic awl. All horses were exercised, five horses were evaluated after 4 months and five horses after 12 months. Gross, histologic, and histomorphometric examination of defect sites and repair tissues was performed, as was collagen typing of the repair tissue. RESULTS: On gross observation a greater volume of repair tissue filled treated defects (74%) compared with control defects (45%). Histomorphometry confirmed more repair tissue filling treated defects, but no difference in the relative amounts of different tissue types was observed. There was an increased percentage of type II collagen in treated defects compared with control defects and evidence of earlier bone remodeling as documented by changes in porosity. CONCLUSIONS: In full-thickness chondral defects in exercised horses, treatment with subchondral bone microfracture increased the tissue volume in the defects and the percentage of type II collagen in the tissue filling the defects when compared to nontreated defects. CLINICAL RELEVANCE: No negative effects of the microfracture technique were observed and some of the beneficial effects are the basis for recommending its use in patients cases with exposed subchondral bone.

Animals↗
PubMedDate not supplied

Internal and external tibial rotation strength after anterior cruciate ligament reconstruction using ipsilateral semitendinosus and gracilis tendon autografts.

The internal and external tibial rotation torques of subjects who had undergone anterior cruciate ligament reconstruction using semitendinosus and gracilis tendon grafts were measured to determine whether harvest of the tendons results in weakness of tibial internal and external rotation. Cybex NORM dynamometer examinations were performed to measure internal and external tibial torque at angular velocities of 60, 120, and 180 deg/sec in 23 subjects. The sex-specific average torque data of the reconstructed limbs were compared with those of the contralateral limbs. Relative internal and external torque scores were calculated for each subject by subtracting the peak torque of the reconstructed knee from that of the contralateral knee. These relative scores were averaged and compared with the null hypothesis that each score should be statistically similar to zero. Subjects were evaluated at an average of 51 +/- 40 months postoperatively. The mean relative internal torque scores of the reconstructed limbs showed a statistically significant decrease from those of the contralateral limbs at all angular velocities. The mean relative external torque scores of the reconstructed limbs were statistically similar to those of the contralateral limbs at all angular velocities. Subjects who had undergone ligament reconstruction using semitendinosus and gracilis tendons demonstrated internal tibial rotation weakness in their reconstructed knees compared with their contralateral knees at all angular velocities tested. These results suggest that semitendinosus and gracilis tendon harvest causes weakness of internal tibial rotation.

Adult↗