Lyle J. Micheli

Non-contact ACL injuries in female athletes: an International Olympic Committee current concepts statement

The incidence of anterior cruciate ligament (ACL) injury remains high in young athletes. Because female athletes have a much higher incidence of ACL injuries in sports such as basketball and team handball than male athletes, the IOC Medical Commission invited a multidisciplinary group of ACL expert clinicians and scientists to (1) review current evidence including data from the new Scandinavian ACL registries; (2) critically evaluate high-quality studies of injury mechanics; (3) consider the key elements of successful prevention programmes; (4) summarise clinical management including surgery and conservative management; and (5) identify areas for further research. Risk factors for female athletes suffering ACL injury include: (1) being in the preovulatory phase of the menstrual cycle compared with the postovulatory phase; (2) having decreased intercondylar notch width on plain radiography; and (3) developing increased knee abduction moment (a valgus intersegmental torque) during impact on landing. Well-designed injury prevention programmes reduce the risk of ACL for athletes, particularly women. These programmes attempt to alter dynamic loading of the tibiofemoral joint through neuromuscular and proprioceptive training. They emphasise proper landing and cutting techniques. This includes landing softly on the forefoot and rolling back to the rearfoot, engaging knee and hip flexion and, where possible, landing on two feet. Players are trained to avoid excessive dynamic valgus of the knee and to focus on the “knee over toe position” when cutting.

Youth Resistance Training: Updated Position Statement Paper From the National Strength and Conditioning Association

Faigenbaum, AD, Kraemer, WJ, Blimkie, CJR, Jeffreys, I, Micheli, LJ, Nitka, M, and Rowland, TW. Youth resistance training: Updated position statement paper from the National Strength and Conditioning Association. J Strength Cond Res 23(5): S60-S79, 2009-Current recommendations suggest that school-aged youth should participate daily in 60 minutes or more of moderate to vigorous physical activity that is developmentally appropriate and enjoyable and involves a variety of activities (219). Not only is regular physical activity essential for normal growth and development, but also a physically active lifestyle during the pediatric years may help to reduce the risk of developing some chronic diseases later in life (196). In addition to aerobic activities such as swimming and bicycling, research increasingly indicates that resistance training can offer unique benefits for children and adolescents when appropriately prescribed and supervised (28,66,111,139,147,234). The qualified acceptance of youth resistance training by medical, fitness, and sport organizations is becoming universal (5,6,8,12,18,33,104,167,192,215). Nowadays, comprehensive school-based programs are specifically designed to enhance health-related components of physical fitness, which include muscular strength (169). In addition, the health club and sport conditioning industry is getting more involved in the youth fitness market. In the U.S.A., the number of health club members between the ages of 6 and 17 years continues to increase (127,252) and a growing number of private sport conditioning centers now cater to young athletes. Thus, as more children and adolescents resistance train in schools, health clubs, and sport training centers, it is imperative to determine safe, effective, and enjoyable practices by which resistance training can improve the health, fitness, and sports performance of younger populations. The National Strength and Conditioning Association (NSCA) recognizes and supports the premise that many of the benefits associated with adult resistance training programs are attainable by children and adolescents who follow age-specific resistance training guidelines. The NSCA published the first position statement paper on youth resistance training in 1985 (170) and revised this statement in 1996 (72). The purpose of the present report is to update and clarify the 1996 recommendations on 4 major areas of importance. These topics include (a) the potential risks and concerns associated with youth resistance training, (b) the potential health and fitness benefits of youth resistance training, (c) the types and amount of resistance training needed by healthy children and adolescents, and (d) program design considerations for optimizing long-term training adaptations. The NSCA based this position statement paper on a comprehensive analysis of the pertinent scientific evidence regarding the anatomical, physiological, and psychosocial effects of youth resistance training. An expert panel of exercise scientists, physicians, and health/physical education teachers with clinical, practical, and research expertise regarding issues related to pediatric exercise science, sports medicine, and resistance training contributed to this statement. The NSCA Research Committee reviewed this report before the formal endorsement by the NSCA. For the purpose of this article, the term children refers to boys and girls who have not yet developed secondary sex characteristics (approximately up to the age of 11 years in girls and 13 years in boys; Tanner stages 1 and 2 of sexual maturation). This period of development is referred to as preadolescence. The term adolescence refers to a period between childhood and adulthood and includes girls aged 12-18 years and boys aged 14-18 years (Tanner stages 3 and 4 of sexual maturation). The terms youth and young athletes are broadly defined in this report to include both children and adolescents. By definition, the term resistance training refers to a specialized method of conditioning, which involves the progressive use of a wide range of resistive loads and a variety of training modalities designed to enhance health, fitness, and sports performance. Although the term resistance training, strength training, and weight training are sometimes used synonymously, the term resistance training encompasses a broader range of training modalities and a wider variety of training goals. The term weightlifting refers to a competitive sport that involves the performance of the snatch and clean and jerk lifts. This article builds on previous recommendations from the NSCA and should serve as the prevailing statement regarding youth resistance training. It is the current position of the NSCA that:A properly designed and supervised resistance training program is relatively safe for youth.A properly designed and supervised resistance training program can enhance the muscular strength and power of youth.A properly designed and supervised resistance training program can improve the cardiovascular risk profile of youth.A properly designed and supervised resistance training program can improve motor skill performance and may contribute to enhanced sports performance of youth.A properly designed and supervised resistance training program can increase a young athletes resistance to sports-related injuries.A properly designed and supervised resistance training program can help improve the psychosocial well-being of youth.A properly designed and supervised resistance training program can help promote and develop exercise habits during childhood and adolescence.

Patterns of flexibility, laxity, and strength in normal shoulders and shoulders with instability and impingement

Imbalance of the internal and external rotator muscu lature of the shoulder, excess capsular laxity, and loss of capsular flexibility, have all been implicated as etio logic factors in glenohumeral instability and impinge ment syndrome; however, these assertions are based largely on qualitative clinical observations. In order to quantitatively define the requirements of adequate pro tective synergy of the internal and external rotator musculature, as well as the primary capsulolabral re straints, we prospectively evaluated 53 subjects: 15 asymptomatic volunteers, 28 patients with glenohu meral instability, and 10 patients with impingement syndrome. Range of motion was evaluated by gonio metric technique in all patients with glenohumeral insta bility and impingement. Laxity assessment was per formed and anterior, posterior, and inferior humeral head translation was graded on a scale of 0 to 3+. Isokinetic strength assessment was performed in a modified abducted position using the Biodex Clinical Data Station with test speeds of 90 and 180 deg/sec. Internal and external rotator ratios and internal and external rotator strength deficits were calculated for both peak torque and total work. Patients with impingement demonstrated marked lim itation of shoulder motion and minimal laxity on drawer testing. Both anterior and multidirectional instability pa tients had excessive external rotation as well as in creased capsular laxity in all directions. Sixty-eight per cent of the patients with instability had significant im pingement signs in addition to apprehension and capsular laxity. Isokinetic testing of asymptomatic subjects demon strated a 30% greater internal rotator strength in the dominant shoulder. Comparison of all three experimen tal groups demonstrated a significant difference be tween internal and external rotator ratios for both peak torque and total work. Conclusions are that there appears to be a domi nance tendency with regard to internal rotator strength in asymptomatic individuals. Impingement syndrome and anterior instability have significant differences in both strength patterns of the rotator muscles and flex ibility and laxity of the shoulder. Isokinetic testing po tentially may be helpful in diagnostically differentiating between these two groups in cases where there is clinical overlap of signs and symptoms.

Mechanoreceptors in human cruciate ligaments. A histological study.

We obtained human cruciate ligaments at the time of total knee replacement and from autopsy and amputation specimens, and examined histological sections of the ligaments for the presence of mechanoreceptors using the Bodian, Bielschowsky, and Ranvier gold-chloride stains for axons and nerve-endings. The cruciate ligaments obtained at the time of total knee replacement were too distorted by disease processes to be of use. The autopsy and amputation specimens, however, contained fusiform mechanoreceptor structures measuring 200 by seventy-five micrometers, with a single axon exiting from the capsule of the receptor. One to three receptors were found at the surface of each ligament beneath the synovial membrane, and were absent from the joint capsules and menisci. Morphologically the receptors resembled Golgi tendon organs, and it seems likely that they provide proprioceptive information and contribute to reflexes inhibiting injurious movements of the knee. This is the first histological demonstration of mechanoreceptors in human cruciate ligaments.

Articular Cartilage Lesions of the Knee

From *Santa Monica Orthopaedic and Sports Medicine Group, Santa Monica, California; ‡University of Missouri at Kansas City and University of Kansas, Shawnee Mission, Kansas; §Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania; iDivision of Sports Medicine, Children’s Hospital, Boston, Massachusetts; Baylor Sports Medicine Group, Houston, Texas; Orthopaedische Universitaetsklinik, Freiburg, Germany; Brigham Orthopedic Association, Boston, Massachusetts; and Gothenburg Medical Center, Vastra Frolunda, Sweden

Scapulothoracic motion in normal shoulders and shoulders with glenohumeral instability and impingement syndrome : a study using Moiré topographic analysis

Qualitative visual inspection and manual muscle testing are traditional methods of evaluation that may overlook subtle weakness of the axioscapular musculature. A modification of the standard technique of Moiré topographic analysis of spinal deformity was applied to assess axioscapular muscle function in 51 subjects: 22 asymptomatic individuals, 22 with shoulder instability, and seven with impingement syndrome. Static Moiré evaluation demonstrated scapulothoracic asymmetry or increased topography in 14% of asymptomatic subjects, compared with 32% and 57% in the instability and impingement groups, respectively. The dynamic Moiré test demonstrated an abnormal Moiré pattern in 18% of asymptomatic individuals, compared with 64% and 100% in the instability and impingement groups, respectively. Axioscapular muscle dysfunction is common with both instability and impingement syndrome of the shoulder, although it remains to be determined whether this represents a primary or secondary phenomenon.

Autologous chondrocyte implantation of the knee: multicenter experience and minimum 3-year follow-up.

ObjectiveTo determine clinical outcome and graft survivorship in patients undergoing autologous chondrocyte implantation (ACI) for the repair of chondral defects of the knee. DesignProspective cohort study. Setting19 centers in the United States. Patients50 patients (37 males, 13 females). Mean age was 36 years (range: 19–53). Defects were grade III or IV with a mean size of 4.2 cm 2 . All patients had a minimum of 36 months postoperative follow-up. Main Outcome MeasurementsClinician and patient evaluation based on the modified Cincinnati Knee Rating System. Graft failure was defined as replacement or removal of the graft due to mechanical symptoms or pain. ResultsClinician and patient evaluation indicated median improvements of 4 and 5 points, respectively, at 36 months following ACI (p < 0.001). Previous treatment with marrow stimulation techniques and size of defect did not impact the results with ACI. The most common adverse events reported were adhesions and arthrofibrosis and hypertrophic changes. Three patients had graft failure and required reimplantation or treatment with alternative cartilage repair techniques. Kaplan-Meier estimated freedom from graft failure was 94% at 36 months postoperatively (95% CI = 88–100%). ConclusionsThese results of this study indicate excellent graft survivorship using ACI as well as substantial improvement in functional outcome.

Reflex sympathetic dystrophy in children. Clinical characteristics and follow-up of seventy patients.

We report on the experience with our first seventy patients who had reflex sympathetic dystrophy and were less than eighteen years old (average age, 12.5 years). In our series, the patients were predominantly girls (male to female ratio, 11:59) and the lower extremity was involved most often (sixty-one of the seventy patients). The average time from the initial injury to the diagnosis was one year, which indicates that the syndrome remains under-recognized in patients in this age-group. Conservative treatment with physical therapy, transcutaneous electrical nerve stimulation, psychological therapies including cognitive-behavioral management and relaxation training, and tricyclic anti-depressants was effective in improving the average scores for pain and function for forty patients. Sympathetic blocks were helpful for twenty-eight of thirty-seven patients. Thirty-eight of the seventy patients in the series continued to have some degree of residual pain and dysfunction. Reflex sympathetic dystrophy in children differs in presentation and clinical course from the syndrome in adults. It is best treated in a multidisciplinary fashion.

Bankart Repair for Anterior Instability of the Shoulder. Long-Term Outcome*†

Anterior instability of the shoulder is a commonly encountered entity in orthopaedic practice. The Bankart procedure is considered by many surgeons to be the treatment of choice for this condition. Despite its widespread popularity, there have been no studies on the long-term outcome of the Bankart procedure as far as we know. Sixty shoulders (fifty-six patients) that had been followed for a minimum of eight years after a Bankart procedure were evaluated for range of motion, stability, and strength according to the data form of the American Shoulder and Elbow Surgeons for examination of the shoulder. The results for the involved shoulder were compared with the findings for the contralateral, normal shoulder. All patients completed a questionnaire regarding the history of the instability of the shoulder, the level of participation in sports before and after the operation, the preoperative and postoperative level of pain, and whether the patient had ever sustained a dislocation that needed reduction by a physician. Information about the current ability of the patient to function at home, at work, and during sports also was requested. In addition, the patients were asked to rate the results of the operation and to indicate whether they would have the same procedure again for the same problem. At a mean of 11.9 years after the operation, the mean loss of external rotation was 12 degrees (range, 0 to 30 degrees) (p < 0.0001). There were no significant differences in forward elevation, abduction, or internal rotation between the involved shoulder and the contralateral, normal shoulder. One patient had crepitus on glenohumeral motion. Fifty-five of the fifty-six patients returned to the occupation that they had had preoperatively, without having to alter their activities. Twenty-eight patients had mild pain with strenuous activity, and one patient had pain at rest. Three patients had a dislocation of the involved shoulder because of a new traumatic event more than three years postoperatively. Fifty-two patients rated the result as good or excellent; three, as fair; and one, as poor. Fifty-four patients said that they would have a Bankart procedure performed again for the same problem. We present a new system for rating the shoulder that emphasizes function and is based specifically on the goals stated by the patients to be most important with regard to the shoulder. Using this system, we found that the Bankart procedure offers an excellent objective long-term outcome with a high degree of patient satisfaction.

Clinical outcome of autologous chondrocyte implantation at 5 years in US subjects.

Peterson’s pioneering experience with the first clinical application of autologous chondrocyte implantation showed improvement in clinical outcomes, durable as much as 11 years, for a difficult patient population. An assessment of the general applicability of this technology in the United States requires long-term, multicenter followup. The purpose of this multicenter cohort study was to assess the clinical outcomes of patients treated with autologous chondrocyte implantation for lesions of the distal femur. Modified 10-point scales of the Cincinnati knee rating system were used to measure outcomes assessments at baseline and at 5 years. Eighty-seven percent (87 of 100) of patients completed 5-year followup assessments. Patients were an average 37 years of age, had a mean total defect size of 4.9 cm2, and had low baseline overall condition scores. At least one prior cartilage repair procedure had failed in 70% of the patients. At followup, 87 patients reported a mean improvement of 2.6 points in the overall condition score, including 62 with improved conditions, six with no change in condition, and 19 with worsened conditions. Of the 62 patients who improved, the mean overall condition score improved 4.1 points at followup. Patients treated with autologous chondrocyte implantation for large cartilage defects in the distal femur reported improvement in outcome scores at 5 years followup. Level of Evidence: Therapeutic study, Level II-1 (prospective cohort study). See the Guidelines for Authors for a complete description of levels of evidence.