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Strenuous physical activity is known to cause structural abnormalities in the immature vertebral body. Concern that exposure to years of intense athletic training may increase the risk for developing adolescent hyperkyphosis in certain sports, as well as the known association between hyperkyphosis and adult-onset back pain, led us to examine the association between cumulative hours of athletic training and the magnitude of the sagittal curvature of the immature spine. A sample of 2,270 children (407 girls and 1,863 boys) between 8 and 18 years of age were studied. An optical raster-stereographic method was used to measure the mid-sagittal curvatures of the surface of the back while the subject was in the upright standing position to quantify the angles of thoracic kyphosis and lumbar lordosis. These data were then correlated with self-reported hours of training measured by interview and questionnaire. The possible effects of age, sex, sport, and upper and lower body weight training were investigated. The results in these young athletes showed that larger angles of thoracic kyphosis and lumbar lordosis were associated with greater cumulative training time. Gymnasts showed the largest curves. Lack of sports participation, on the other hand, was associated with the smallest curves. Age and sex did not appear to affect the degree of curvature.

An estimated 80,000 anterior cruciate ligament (ACL) tears occur annually in the United States. The highest incidence is in individuals 15 to 25 years old who participate in pivoting sports. With an estimated cost for these injuries of almost a billion dollars per year, the ability to identify risk factors and develop prevention strategies has widespread health and fiscal importance. Seventy percent of ACL injuries occur in noncontact situations. The risk factors for non-contact ACL injuries fall into four distinct categories: environmental, anatomic, hormonal, and biomechanical. Early data on existing neuromuscular training programs suggest that enhancing body control may decrease ACL injuries in women. Further investigation is needed prior to instituting prevention programs related to the other risk factors.

In the general population, an estimated one in 3000 individuals sustains an anterior cruciate ligament injury per year in the United States, corresponding to an overall injury rate of approximately 100,000 injuries annually. This national estimate is low for women because anterior cruciate ligament injury rates are reported to be two to eight times higher in women than in men participating in the same sports, presenting a sizable health problem. With the growing participation of women in athletics and the debilitating nature of anterior cruciate ligament injuries, a better understanding of mechanisms of injury in women sustaining anterior cruciate ligament injuries is essential. Published studies strongly support noncontact mechanisms for anterior cruciate ligament tears in women, which make these injuries even more perplexing. Speculation on the possible etiology of anterior cruciate ligament injuries in women has centered on anatomic differences, joint laxity, hormones, and training techniques. Investigators have not agreed on causal factors for this injury, but they have started to profile the type of athlete who is at risk. In the current study the most recent scientific studies of intrinsic and extrinsic risk factors thought to be contributing to the high rate of female anterior cruciate ligament injuries will be reviewed, important differences will be highlighted, and recommendations proposed to alleviate or minimize these risk factors among female athletes will be reported where appropriate.

Summary: Hip arthroscopy is a technically difficult procedure to perform. A limited anterior approach to the joint has made hip arthroscopy technically less difficult in our hands and has enabled us to treat a wide range of hip pathology. Five hip arthroscopies were performed using a modified 4-cm Smith-Petersen anterior approach to the hip exposing the joint capsule as manual traction is applied. The arthroscope is then easily introduced making visualization of the hip joint possible. The 5 hip arthroscopies resulted in either removal of loose bodies or debridement of an osteochondral fragment, synovitis, or cartilaginous debris. There were no complications postoperatively. We believe that hip arthroscopy through a limited anterior approach provides an easy and safe alternative method for arthroscopic access to the hip joint. Importantly, there is a decreased risk of neurovascular trauma and iatrogenic damage to the articular cartilage and acetabular labrum when introducing instruments into the hip joint.

This investigation explored alternatives to the null hypotheses that maximal active and passive resistance to inversion developed by a near-maximally inverted and weightbearing ankle is not altered by 1) the use of prophylactic adhesive athletic tape, 2) the use of non-adhesive prewrap (underwrap), or 3) 40 minutes of vigorous exercise. Ten healthy men and 10 healthy women (mean age, 25 +/- 3 years) with no recent ankle injuries underwent testing to determine maximal ankle resistance to inversion under unipedal, weightbearing conditions. Tests were performed with and without the support of athletic tape, and before and after 40 minutes of exercise. Half the testing sessions were performed with prewrap under the tape. At 15 degrees of inversion, without any external ankle support, healthy young men and women could maximally resist a mean (SD) inversion moment of 52.9 (6.4) N-m and 28.3 (5.8) N-m, respectively. Although use of ankle tape provided a 10% increase in maximal resistance to inversion moments, this increase diminished to insignificant levels after 40 minutes of vigorous exercise. Use of prewrap improved maximal resistance to inversion by more than 10%.

At this time, meniscal allograft transplantation remains an investigational procedure with very limited indications. To date, no work has shown that the transplanted meniscus is capable of protecting and, preserving the hyaline cartilage of the knee joint. The technical aspects of the procedure have been established and are reproducible. Furthermore, it is apparent that a systemic rejection phenomenon does not seem to occur, and the transplanted meniscus is capable of healing. MR imaging appears to be the best method of assessing postoperative position of the transplanted meniscus in the knee. If the transplanted meniscus cannot be maintained in an anatomic position during weight bearing, it is unlikely to have any functional role. Questions remain with regard to the best way to preserve and sterilize the meniscus and whether the transplanted allograft meniscus is capable of assuming the multifaceted role of the normal meniscus in the knee. As more work is conducted, these questions will be answered, and a better understanding of the efficacy of this novel technique will be achieved.

The purpose of this project was to evaluate magnetic resonance imaging (MRI) accuracy for diagnosing and defining meniscal pathology. The charts of 45 patients who underwent both MRI and arthroscopy were viewed retrospectively. All cases were seen by one of two orthopedic surgeons. Magnetic resonance imaging scans were reviewed by staff radiologists at the University of Michigan Hospital Medical Center. Arthroscopy was used as the standard for comparing MRI results. Data were analyzed two ways with respect to questionable (code 3) MRI lesions. First, all code 3 lesions were interpreted as either true positives or negatives. Second, all code 3 lesions that corresponded with a negative arthroscopy finding were interpreted as false positives. The MRI accuracy was 87.8% when considering nonmatching code 3 lesions as true positives or negatives. The accuracy declined to 82.2% when considering code 3 lesions as false negatives. Magnetic resonance imaging sensitivity for medial meniscal and lateral meniscal tears was 84.6% and 87.5%, respectively, regardless of code 3 interpretation. The specificity for medial meniscal tears with and without the negative effect was 71.9% and 84.4%, respectively. The specificity with and without considering code 3 lesions as false positives was 89.2%, and 91.9%, respectively.

This case report describes the immunocytochemical examination of tissue from a 9-year-old black child diagnosed with congenital insensitivity to pain at age 5. A recent fall and resulting patella fracture required surgical treatment. Biopsies of the distal pole and surrounding soft tissue, as well as a sample of his patellofemoral joint fluid, were taken at the time of partial patellectomy and analyzed for substance-P (SP). Morphologic staining of the patella showed a grossly degenerated patellofemoral articular surface. Examination of tissue sections stained either immunocytochemically with diaminobenzidine DAB or by a rhodamine fluorescent labeling technique showed no evidence of SP-positive nerve fibers. Furthermore, only a trace amount of SP (7.29 pg/ml) was detected in a sample of the patient's knee joint synovial fluid. This patient's absence of pain sensation in conjunction with the absence of SP nerve fibers in stained patella sections and identification of only trace levels of SP in his synovial fluid, further implicates this neuropeptide in nociceptive innervation of diarthrodial joints.

Some degree of uncertainty remains in the natural history of anterior cruciate ligament (ACL) tears treated conservatively with a supervised rehabilitation program, counseling, and activity modifications. Symptomatic ACL-deficient individuals usually present for treatment, whereas the asymptomatic may not, thus making the true outcome difficult to discern. The goal of this study was to identify which prognostic indicators available at the initial evaluation of an ACL-deficient knee could predict future disability. The hospital records of 107 individuals who presented with an ACL-deficient knee (confirmed by arthroscopy) were reviewed. Follow-up (mean 51.7 months) was obtained on 99 individuals (93%) by telephone interview. The study sample was composed of 72 males (67%), 83 acute injuries (78%), and 91 complete ACL tears (85%). Furthermore, 81 individuals presented initially with associated knee injuries (87%), whereas 73 injuries were sports related (68%). Associated injuries included 47 lateral meniscal tears (54%), 37 medial meniscal tears (42.5%), 52 hyaline cartilage injuries (59.8%), and 16 other ligament injuries (18.4%). Those individuals with associated injuries to the meniscus did not show a reduction in the ability to run, secondary to pain and/or swelling. However, those individuals with hyaline cartilage defects did decrease their running due to pain and swelling.(ABSTRACT TRUNCATED AT 250 WORDS)

The neuromuscular function of the lower extremity in 40 normal and 100 anterior cruciate ligament-deficient volunteers was evaluated by physical examination, KT-1000 arthrometer measurements, isokinetic strength and endurance testing, subjective functional assessment, and an anterior tibial translation stress test. A specially designed apparatus delivered an anteriorly directed step force to the posterior aspect of the leg while anterior tibial translation was monitored and electromyographic signals were recorded at the medial and lateral quadriceps, medial and lateral hamstrings, and gastrocnemius muscles. Testing was done at 30 degrees of knee flexion with the foot fixed to a scale to monitor weightbearing, while the tibia remained unconstrained. Results indicate that muscle timing and recruitment order in response to anterior tibial translation are affected by anterior cruciate ligament injury. These alterations in muscle performance change with time from injury, correlate with an individual's physical activity level, affect subjective functional parameters, and are directly related to the degree of dynamic anterior tibial laxity seen with stress testing.

The KT-1000 arthrometer was evaluated in vitro and in vivo to determine accuracy and quantify effects of potential error sources in clinical application. The KT-1000 arthrometer in vitro accuracy was evaluated by making 30 measurements of 13 known displacements (range, +15 to -15 mm). The effect of applied force on malalignment measurements was evaluated in vitro by making repeated measurements with force applied 5 degrees, 10 degrees, and 15 degrees from the vertical position. The effect of malpositioning the device along the joint line was evaluated in vivo by making repeated measurements 1 cm proximal and 1 cm distal to the joint line. The KT-1000 arthrometer was accurate in vitro (average error, 0.13 mm; SD, 0.12 mm). The range of measurements increased when the angle of force application was increased. Positioning the device 1 cm proximal to the joint line produced larger anterior translation measurements in vivo than those at the joint line (5.8 versus 5.4 mm), while positioning it 1 cm distal produced smaller measurements (4.4 mm). The KT-1000 arthrometer's accuracy indicates great potential for clinical application, but one must ensure that the displacing force is directed properly and the device is positioned accurately over the joint line.

It is well-documented that electrical potentials normally are present in biologic soft tissues. The discovery of these has generated interest in effecting a change in the biology of these tissues by externally imposing an electrical field. There is experimental evidence that ligament and tendon repair can be affected by ES, but there have been no clinical studies to demonstrate its effectiveness in human ligament or tendon injuries. The only clinical support for use of ES to enhance soft-tissue healing is for its use in chronic, open dermal wounds. ES has been shown to be effective for these chronic wounds under certain conditions. There is currently insufficient justification for the use of ES for reduction of soft-tissue edema.

We used five randomly selected cadaver specimens to evaluate the Anderson Knee Stabler and the Lenox Hill Knee Brace, individually and in combination with an anterior cruciate ligament protective tape method. Reduction of total laxity, as well as a defined pathologic anterior-posterior translation and internal-external rotation, was tested after the anterior cruciate and medial collateral ligaments of the specimens had been sectioned. Displacements were produced pneumatically; loads were applied to the tibia with the knee in 50 degrees of flexion. The tape and Lenox Hill Brace combination showed the greatest reduction in both anterior-posterior translation and internal-external rotation. The Lenox Hill Brace and the tape method used individually both restricted anterior-posterior translation and internal-external rotation better than the Stabler Brace alone. This study provides objective evidence of the restraining capabilities of these protective systems that may prove to be beneficial in the clinical setting.

Twenty-two patients with Grade III acromioclavicular (AC) joint dislocations were treated nonoperatively and evaluated by questionnaire, physical exam, and isokinetic strength and endurance testing. The mean follow-up time was 2.6 years (range, six months to 7.7 years). Patients returned to work an average of 2.1 weeks after injury. All of the patients were right-handed; 14 injured their dominant right AC joint whereas eight injured their nondominant left side. Isokinetic muscle testing was used to evaluate the strength and endurance of both shoulders in all 22 patients. Strength was measured as peak torque for shoulder flexion, extension, internal and external rotation, abduction, and adduction at 400 degrees per second. Internal and external rotation testing was also evaluated at 60 degrees per second. Endurance was measured at 400 degrees per second for flexion, extension, and internal and external rotation. The strength and endurance levels of the injured shoulders were comparable to the noninjured side. Although discomfort levels were low, long range follow-up reports reveal discomfort appearing with increased intensity of activity.

Developmental patella infera and associated arthrofibrosis after knee surgery require prompt recognition and treatment. The condition develops because of contracture of peripatellar tissues, fatpad tissues, and quadriceps weakness, and may rapidly progress to permanent patella infera and disabling patellofemoral arthrosis. Case studies for five patients with acute developmental patella infera are described. All patients required an early arthroscopic release of contracted tissues. To establish normal right to left patellar, vertical-height ratios, lateral roentgenograms were obtained in 202 normal knees (101 pairs). The data showed that although essentially no difference existed between right and left sides, large variations existed in the ratios from one individual to another (range, 0.75-1.46). Thus, the diagnosis of developmental patella infera requires comparison of patellar height ratios in the same knee or between knees in the same individual. A decrease in the vertical-height ratio of 11%-15%, depending on the method used, indicates developmental patella infera.

Recreational sports injuries are expensive to society. Prevention of such injuries must be a major public health goal. In a previous retrospective study, base sliding was found to be responsible for 71% of recreational softball injuries. Because most injuries occurred during rapid deceleration against stationary bases, quick-release (break-away) bases were evaluated as a means to modify this mechanism of injury. In a prospective study, 633 softball games were played on a break-away base fields and 627 games were played on stationary base fields. Forty-five sliding injuries occurred on the stationary base diamonds (1 injury for every 13.9 games) and only two sliding injuries occurred on the break-away fields (1 injury for every 316.5 games). The medical costs for injuries on the stationary base fields was 79 times greater than that on the break-away fields. In a 1035 game follow-up study performed on all fields equipped with break-away bases, two sliding injuries occurred (1 injury for every 517.5 games). Installing break-away bases in fields used by recreational leagues would achieve a significant reduction of serious softball injuries (98%) and, therefore, should be mandatory. Based on our findings, the Centers for Disease Control has estimated 1.7 million injuries would be prevented nationally per year, saving $2.0 billion per year nationally in acute medical care costs.

We assessed the relative restraints that are provided by fourteen currently available functional knee-braces, using six limbs in cadavera. The tests were made at 30 and 60 degrees of flexion of the knee, and a mechanical loading system applied loads that caused anterior-posterior translation and internal-external rotation. The braces limited abnormal tibiofemoral displacements by 10 to 75 per cent in translation; there was more variation in rotation. This study demonstrated that functional knee-braces provide a restraining influence that may be beneficial in the control of abnormal displacements of the knee, but that the degree of restraint varies considerably.

Patients with pyarthrosis of the knee can be effectively managed by several different methods. A retrospective review of patients with the diagnosis of septic arthritis of the knee was undertaken to determine the efficacy of two different treatment programs. Multiple-needle arthrocentesis was contrasted with formal arthrotomy drainage. In this series, patients with a longer than three-day history of a knee pyarthrosis and those with Staphylococcus aureus or enteric gram-negative organisms on culture benefited from open drainage procedures in lieu of repeated aspiration techniques.

Anterior knee pain is a frequent musculoskeletal complaint affecting all ages, both sexes, athletes, and nonathletes alike. Numerous theories have been proposed regarding its etiology including patellar malalignment, quadriceps insufficiency, subluxation, quadriceps muscle tightness, and chondral defects. However, the mechanism by which these factors produce this pain is not clear. Knowledge of the distribution of nociceptive nerve fibers around the knee would seem to provide insight in treating these painful conditions. Eleven human patellae--eight specimens from patients with degenerative patellofemoral disease and three normals--were evaluated. Immunohistochemical techniques using monoclonal antibody to substance-P were employed to identify nociceptive fibers. Substance-P is a nociceptive neurotransmitter found in afferent nerve fibers. Substance-P fibers were isolated in the retinaculum, fat pad, periosteum, and subchondral plate of patellae affected with degenerative disease. This study demonstrates that selective tracting of nociceptive pain fibers is possible around the knee both in soft tissue and, in some circumstances, bone. The subchondral plate of normal patellae did not demonstrate erosion channels, but those with chondral defects from degenerative disease did. Nociceptive fibers found in these defects may explain the origin of symptoms in some patients. The distribution of substance-P nerve fibers in the soft tissues around the knee suggests that denervation may be the mechanism by which surgical procedures for anterior knee pain produce favorable results.

In a previous retrospective study, base sliding was found to be responsible for 71% of recreational softball injuries. As most injuries occurred following rapid deceleration impact against stationary bases, quick-release (breakaway) bases were evaluated as a means to modify this mechanism of injury. Six hundred thirty-three softball games were played on breakaway-base fields and 627 games were played on stationary-base fields. Forty-five sliding injuries (7%) occurred on the stationary-base diamonds and only two sliding injuries (less than 1%) occurred on the breakaway-base fields. Implementing the use of breakaway bases in recreational softball leagues could potentially achieve a significant, cost-effective reduction of injuries.

Volar flexion intercalated segment instability may develop after many different injuries to the skeletal and ligamentous architecture of the wrist. We describe two cases in which the presumed cause of instability was an injury to the extrinsic volar scapho-trapezial ligament complex.

The care of the pediatric athlete should not be viewed as caring for small adults. Growing bones, tendons, ligaments, and muscles respond differently to stress. Proper training and conditioning can remedy most problems in the immature athlete.

Rupture of the distal insertion of the biceps brachii may lead to severe functional impairment of the upper extremity on the basis of resultant weakness of elbow flexion and supination. When the diagnosis of a posttraumatic distal biceps tendon avulsion is made, a simple method of reattachment is possible and functionally warranted.

This study was conducted to determine the effectiveness of the Lenox Hill knee brace in limiting anterior translation and external rotation of the tibia in reference to the femur in normal and ligament-deficient knees. Four fresh cadaver knees were fitted with Lenox Hill knee braces according to the manufacturer's guidelines. A computer-assisted testing apparatus was constructed that allowed each knee to be tested as a function of knee flexion angle, joint load, and soft tissue integrity. Each knee served as its own control. While 45 kg of anterior force was applied to the tibia of the anterior cruciate ligament deficient knees, the Lenox Hill knee brace was able to decrease anterior translation from an average of 10 mm, to 5.7 mm, at 30 degrees of flexion when no vertical load was present. This limiting effect was lost when the medial collateral ligament was sectioned in addition to the anterior cruciate ligament or when both the medial and the lateral collateral ligaments were sectioned along with the anterior cruciate ligament. When 20 Newton-meters (Nm) of torque was applied to the femurs at 30 degrees of flexion without vertical load, the Lenox Hill knee brace limited external rotation of the tibia in all tested categories. For intact knees at 30 degrees of flexion and no vertical load, the Lenox Hill knee brace decreased external rotation from 18 degrees to 10 degrees. In the anterior cruciate ligament-sectioned knees, external rotation was decreased from an average of 20.2 degrees to 16.1 degrees. In the knees with sectioned anterior cruciate and medial collateral ligaments, the average reduction was from 21.2 degrees to 15.4 degrees.(ABSTRACT TRUNCATED AT 250 WORDS)