Sweat rate and fluid turnover in American football players compared with runners in a hot and humid environment.

OBJECTIVES: To determine sweat rate (SwR) and fluid requirements for American footballers practicing in a hot, humid environment compared with cross country runners in the same conditions. METHODS: Fifteen subjects, 10 footballers and five runners, participated. On the 4th and 8th day of preseason two a day practices, SwR during exercise was determined in both morning and afternoon practices/runs from the change in body mass adjusted for fluids consumed and urine produced. Unpaired t tests were used to determine differences between groups. RESULTS: Overall SwR measured in litres/h was higher in the footballers than the cross country runners (2.14 (0.53) v 1.77 (0.4); p<0.01). Total sweat loss in both morning (4.83 (1.2) v 1.56 (0.39) litres) and afternoon (4.8 (1.2) v 1.97 (0.28) litres) practices/runs, and daily sweat losses (9.4 (2.2) v 3.53 (0.54) litres) were higher in the footballers (p<0.0001). The footballers consumed larger volumes of fluid during both morning and afternoon practices/runs (23.9 (8.9) v 5.5 (3.1) ml/min and 23.5 (7.3) v 13.6 (5.6) ml/min; p<0.01). For complete hydration, the necessary daily fluid consumption calculated as 130% of daily sweat loss in the footballers was 12.2 (2.9) litres compared with 4.6 (0.7) litres in the runners (p<0.0001). Calculated 24 hour fluid requirements in the footballers ranged from 8.8 to 19 litres. CONCLUSIONS: The American footballers had a high SwR with large total daily sweat losses. Consuming large volumes of hypotonic fluid may promote sodium dilution. Recommendations for fluid and electrolyte replacement must be carefully considered and monitored in footballers to promote safe hydration and avoid hyponatraemia.

Lateral ankle sprains: a comprehensive review: part 1: etiology, pathoanatomy, histopathogenesis, and diagnosis.

Ankle sprains are among the most common injuries sustained by athletes and seen by sports medicine physicians. Despite their prevalence in society, ankle sprains still remain a difficult diagnostic and therapeutic challenge in the athlete, as well as in society in general. The purpose of this section of our two-part study is to review scope of the problem, the anatomy and biomechanics of the lateral ankle ligaments, review the pathoanatomical correlates of lateral ankle sprains, the histopathogenesis of ligament healing, and define the mechanisms of injury to understand the basis of our diagnostic approach to the patient with this common acute and chronic injury. We extensively review the diagnostic evaluation including historical information and physical examination, as well as options for supplementary radiographic examination. We further discuss the differential diagnosis of the patient with recurrent instability symptoms. This will also serve as the foundation for part two of our study, which is to understand the rationale for our treatment approach for this common problem.

Lateral ankle sprains: a comprehensive review part 2: treatment and rehabilitation with an emphasis on the athlete.

This is the second part of a two-part comprehensive review of lateral ankle sprains. In the first part of our review, we discussed the etiology, natural history, pathoanatomy, mechanism of injury, histopathogenesis of healing, and diagnostic approach to acute and chronic lateral ligamentous ankle injuries. Conservative intervention and treatment of grade I-III and chronic, recurrent sprains of the lateral ankle ligaments and appropriate rehabilitation guidelines are the topics of this article. We review the use and benefit of different modalities and external supports and outline our five-phase intervention program of rehabilitation based on the histopathogenesis of ligament healing. We discuss the expected timing of recovery of the acute injury as well as the management of chronic, recurrent ankle sprains. Treatment of acute ankle sprains depends on the severity of the injury. Conservative therapy has been found to be uniformly effective in treating grade I and II ankle sprains. Some controversy exists regarding the appropriate treatment of grade III injuries, particularly in high-level athletes. Our belief is that the majority of these patients may also be treated well with conservative management. Other options for the management of grade III sprains will be briefly discussed at the end of this article.

Reflex inhibition of the quadriceps femoris muscle after injury or reconstruction of the anterior cruciate ligament.

A burst-superimposition technique was used to assess the strength of the quadriceps femoris muscle in three groups of patients. Group 1 comprised twenty patients who had had a torn anterior cruciate ligament of the knee and had a reconstruction of the ligament one to six months after the injury. Group 2 comprised twelve patients who had had a torn anterior cruciate ligament for an average of three months (a subacute tear). Group 3 comprised eight patients who had had a torn anterior cruciate ligament for an average of two years (a chronic tear). The patients in Groups 2 and 3 had not had an operation for the torn ligament. The patients in Groups 1 and 3 had no evidence of failure of activation of the involved quadriceps, but nine of the twelve patients in Group 2 had reflex inhibition of contraction of the muscle.

Wrist pain syndrome in the gymnast. Pathogenetic, diagnostic, and therapeutic considerations.

Gymnast wrist pain syndrome presents a difficult diagnostic and therapeutic challenge. It is common and debilitating among gymnasts, resulting in a reduction in training and performance, and may be the result of a response to repetitive trauma during the period of growth and development. This study was undertaken to define and characterize factors contributing to the causes and development of gymnast wrist pain and to establish an effective means of systematic and comprehensive evaluation and treatment. Thirty-eight collegiate gymnasts (20 UCLA: 9 female, 11 male; 18 NCAA: all male) were evaluated by radiograph and questionnaire. Seventy-five percent (22) of the males and 33% (3) of the females had had wrist pain for at least 4 months. The UCLA males averaged 2.82 +/- 1.94 mm positive ulnar variance; this was significantly greater than that of the NCAA males, who averaged 1.28 +/- 1.02 mm (P less than 0.02). The UCLA females averaged 1.44 +/- 1.88 mm positive ulnar variance. All of the gymnasts had significantly greater variance than had the controls, who averaged -0.52 mm (P less than 0.0001). The pommel horse routine was consistently responsible for wrist pain among the males. Anatomical and histological correlation of cryosections with magnetic resonance imaging (MRI) was performed to establish the usefulness of MRI in the diagnosis of wrist pain. MRI was able to differentiate the complex transitions between cortical and trabecular bone, articular surfaces, the ligaments, and the triangular fibrocartilage (TFC) complex of the wrist joint. A therapeutic algorithm was established to facilitate the evaluation and management of gymnast wrist pain. Arthroscopic surgery was successful, and arthroscopic findings correlated well with those of MRI and arthrography. Prospective studies are now underway in the pediatric and adolescent population to define further the causes and development of wrist pain problems in gymnasts.

The relationship between passive joint laxity and functional outcome after anterior cruciate ligament injury.

Twenty patients with anterior cruciate ligament-deficient knees were studied. Ten patients returned to all sports activities (compensators) and 10 patients were not improved with nonoperative management and required surgical stabilization (noncompensators). Joint laxity was measured using a KT-2000 arthrometer (manual maximum Lachman). Subjects completed a Lysholm questionnaire and Knee Outcome Score. The International Knee Documentation Committee form was also completed. Patients also rated their knee function on a scale of 1 to 100. There was no difference in level and frequency of athletic activity between the two groups before their anterior cruciate ligament injuries as determined by the knee outcome score. The compensator group had a mean side-to-side difference of 3.25 mm at 89 N and the noncompensators had a mean difference of 3 mm preoperatively. Manual maximum tests gave side-to-side differences of 6.7 mm for the compensators and 6 mm for the noncompensators. There were no differences in laxity measures between groups. The correlation between knee outcome scores and side-to-side laxity measurements were not significant. Measurements of anterior laxity in anterior cruciate ligament-deficient patients were not correlated with measures of functional outcome used in this study. Functional outcome measurements that are partially based on joint laxity measures, such as the International Knee Documentation Committee form, may artificially overestimate the disability after anterior cruciate ligament rupture.

Ethics in sports medicine.

Sports medicine physicians are not exempt from the ethical challenges of medical practice merely because their patients are robust and healthy. In fact, precisely because the patients with sports injuries are so healthy the moral issues remain subtle. Many ethical issues in sports medicine come about because the traditional relationship between doctor and patient is altered or absent. In the current review, several routine topics in biomedical ethics, including doctor and patient confidentiality, informed consent, the care of minors, medical advertising and use of innovative treatments, will be studied from the sports medicine perspective. Hypothetical case histories will be presented, along with an analysis of the underlying ethical issues. The goal of this analysis is not to offer answers to these moral questions, but to increase awareness and promote contemplation of the correct course of action.

Anterior cruciate ligament tears: evaluation of multiple signs with MR imaging.

PURPOSE: To assess the accuracy and reliability of multiple signs of anterior cruciate ligament (ACL) tears with magnetic resonance (MR) imaging. MATERIALS AND METHODS: Two independent reviewers retrospectively evaluated 103 sets of ACL MR images for the presence of 22 signs of ACL tears. There were 43 patients with ACL tears and 58 patients whose ACLs were proved to be intact at surgery. Although variable imaging protocols were used, T1- and T2-weighted images were obtained in nearly all patients. Direct nonvisualization, intrinisc ACL abnormalities, associated osseous and cartilage abnormalities, and other indirect signs were evaluated. RESULTS: Discontinuity of the ACL in the sagittal and axial planes and failure of the fascicles to parallel the Blumensaat line were the most accurate signs of a tear. Discontinuity of the ACL, disruption of fascicles, a posterolateral tibial bruise, a buckled posterior cruciate ligament, positive posterior cruciate ligament line sign and positive posterior femoral line sign were the best predictors of an ACL tear at logistic regression analysis. CONCLUSION: Signs other than nonvisualization of the ACL are good predictors of an ACL tear.

The utility of contrast-enhanced MRI in diagnosis of muscle injuries occult to conventional MRI.

PURPOSE: Our goal was to define the utility of contrast-enhanced MRI in the diagnosis of occult muscle injuries on T2 and STIR sequences. METHOD: We retrospectively reviewed the pre- and postcontrast MR studies of four professional athletes with a clinical diagnosis of suspected muscle injuries. RESULTS: The four cases demonstrated muscle strain injuries not visualized on the conventional T2 and STIR sequences but visualized on the postcontrast MR studies as areas of localized enhancement. CONCLUSION: We recommend the intravenous administration of gadolinium in the setting of clinically suspected muscle injuries not visualized on T2 and STIR sequences.

Review of typical ice hockey injuries. Survey of the North American NHL and Hockey Canada versus European leagues.

Ice hockey is considered to be one of the fastest and roughest of all sports. Prospective injury reports of the North American National Hockey League, the Canadian Amateur Hockey Association and of several European teams (UdSSR, CSSR, Sweden and Switzerland) are reviewed to evaluate the patterns, anatomic locations, circumstances and sequelae of ice hockey-related injuries. Although different injury reporting systems are used in North America and Europe, knee injuries (sprains of the collateral ligaments) accounted for the majority of games missed (40%), followed by injuries to the shoulder (dislocation, acromio-clavicular joint separation, rotator cuff strain and tears, 20%), the groin (15%), and the back (10%). Mandatory helmets and face masks reduced the number of facial and eye injuries to a quarter from 1972 to 1983. The frequency of only concussion but also cervical spine lesions is increasing. The prevention of head, face, eye and neck injuries should mainly be accomplished by enforcement of current rules (mandatory helmets with face masks) and institution of new rules. Improvement in protective equipment would also have the effect of decreasing the frequency of injuries. Ice hockey is the fastest team sport and involves both finesse and controlled aggression. It is also considered to be one of the roughest of all sports. In recent years, ice hockey has grown tremendously in popularity, not only in the United States and in Canada but also in many European countries [1]. The number of both professional and amateur hockey players has increased with the expanding interest in the sport around the world [1].(ABSTRACT TRUNCATED AT 250 WORDS)

Arthroscopic treatment of patellar clunk.

Excellent results have been reported with posterior stabilized total knee arthroplasty. A common complication relating to patellofemoral articulation is patellar clunk syndrome. Patellar clunk syndrome occurs when a fibrous nodule develops just proximal to the patellar button. At approximately 30 degrees to 45 degrees from full extension, the nodule catches the anterior flange of the femoral prosthesis, resulting in the clunk and a painful range of motion. The present study examines the use of arthroscopic debridement for this disorder. Thirty consecutive patients (32 knees) with the diagnosis of patellar clunk syndrome were evaluated at 1 year after arthroscopic debridement. All patients were evaluated clinically and radiographically according to the Knee Society score. In addition, patients were questioned specifically regarding anterior knee pain and patellofemoral symptoms. Radiographs were evaluated further regarding patella and component position. Patients were diagnosed with patellar clunk at an average of 12 months after their latest knee arthroplasty, with a range of 3 to 47 months. All patients complained of anterior knee pain and the clunk. All patients had a hypertrophic nodule at the junction of the proximal pole of the patella and quadriceps tendon and underwent arthroscopic debridement through a superolateral portal. All patients were free of patellar clunk postoperatively; one patient reported persistent anterior knee pain. Knee Society scores increased from an average of 64 points preoperative to 93 points postoperative. Radiographs showed patella alta in eight knees, patella baja in two. Four femoral components were in 5 degrees flexion. The present study represents the largest collection of data regarding patellar clunk syndrome. The data appear to support arthroscopic debridement as a successful treatment of patellar clunk syndrome.

Failure properties of suture anchors in the glenoid and the effects of cortical thickness.

The ultimate pullout strength and fatigue properties of a screw-design suture anchor implanted in the anterior glenoid rim were investigated and compared with results from a nonscrew-design suture anchor. Twenty-two cadaveric glenoids were harvested and one to two anchors were implanted in the superior and inferior quadrants. Fifty-seven Statak 3.5 anchors (Zimmer, Warsaw, IN) were tested and compared with results obtained in a previous study on 50 Mitek GII anchors (Mitek Products, Inc, Westwood, MA). The specimens were mounted on an Instron fatigue testing machine (Instron Corp, Canton, MA) and cycled between preselected minimum and maximum loads until pullout. The Mitek GII maintained a higher pullout strength than the Statak 3.5 after cyclic loading. Cortical thickness at the implantation sites was measured, and found to decrease monotonically from superior to inferior positions. The ultimate pullout strength, and subsequently the fatigue life, of both types of suture anchors depended directly on cortical thickness. The significantly lower performance of both anchors when placed inferiorly emphasizes the importance of correct anchor selection, number, and placement in this region. All anchors settled during the first 10 to 100 cycles, resulting in partial exposure of the implant. Intraoperative cycling of the anchors before suture tying may be necessary to achieve complete settling and prevent subsequent loss of coaptation between capsule and glenoid. The study shows that for the anchors to last 1,000 cycles or more, less than 50% of the theoretical ultimate pullout strength should be applied cyclically. With aggressive early rehabilitation exercises, this significant decrease in fixation strength could shift reconstruction failure from suture breakage or soft tissue tearing to anchor pullout.

Fatigue properties of suture anchors in anterior shoulder reconstructions: Mitek GII.

Suture anchors have simplified anterior capsule labral reconstruction. During rehabilitation the shoulder goes through many repetitions of range of motion exercises. These exercises will repetitively submaximally load the anchor and in theory should reduce the pullout strength of the suture anchor. No published reports exist on the fatigue strengths and properties of one of the most commonly used anchors: Mitek GII suture anchors. Fifty trials of cyclic submaximal load were done on 22 cadaveric glenoids with an average age of 66.8 years (range, 40 to 90 years). At two to three different sites on the same specimen, the anchors were inserted according to manufacturer's specifications. The anchors were tested to failure on a Instron 1331 servohydraulic mechanical testing system at 2 Hertz sinusoidal loading pattern using steel sutures and a predetermined load. There were 22 (44%) tests performed in the superior quadrant and 28 (56%) tests in the inferior quadrant. All anchors pulled out, and no wires broke. There were statistically significant differences between the superior and inferior portion of the glenoid with regard to number of cycles to failure at a given maximum load. The anchors underwent an average of 6,220 cycles before pullout at an average load of 162 N (SD = 73 N). In the superior quadrant, the average ultimate pullout strength was 237 N (SD = 42 N), whereas in the inferior quadrant the average ultimate pullout strength was 126 N (SD = 36 N). Hence, the ultimate pullout strength of the Mitek GII anchor was significantly higher (P < .002) in the superior quadrant than in the inferior quadrant. Using a least squares regression analysis, it was possible to predict the fatigue life of the superiorly and inferiorly placed suture anchors over a wide range of cycles. The R-squared values for trendlines showed good reliability (superior R2 = 0.55; inferior R2 = 0.28). The fatigue life curves for the two different quadrants were normalized using the ultimate pullout strength. This new, universal curve predicts the fatigue life of the Mitek GII anchor as a percentage of the ultimate pullout strength for any selected location. For a clinically relevant number of cycles, no more than approximately 40% to 50% of the ultimate pullout strength of the suture anchor can be cyclically applied to the anchor to guarantee a life for the duration of rehabilitation. For the entire system, the inferiorly placed anchors dictate the amount of cyclically applied load the system can experience without failing, and rehabilitation should be adjusted accordingly.

Rotator cuff tears: prospective comparison of MR imaging with arthrography, sonography, and surgery.

Thirty-eight patients with suspected rotator cuff tears were examined at 1.5 T by using a loop-gap resonator surface coil. The MR findings were compared prospectively in a blinded fashion with the results from double-contrast arthrography in all 38 patients, high-resolution sonography in 23 patients, and surgery in 16 patients. In the total group of 38 patients, MR imaging detected 22 of 22 tears and 14 of 16 intact cuffs as determined by arthrography. In the 16 surgically proved cases, MR and arthrography showed identical results, with 92% sensitivity in the diagnosis of 12 tears and 100% specificity in the diagnosis of four intact cuffs. In a subgroup of 23 patients, sonography detected nine of 15 tears and seven of eight intact cuffs as determined by comparison with arthrography. In 10 surgically proved cases, sonography was 63% sensitive in the diagnosis of eight rotator cuff tears and 50% specific in the diagnosis of two intact cuffs. For the diagnosis of rotator cuff tears, MR imaging is comparable to arthrography in both sensitivity and specificity. In this study, sonography was not as accurate in the diagnosis of rotator cuff tears as were the other two techniques. These results suggest that MR imaging should be considered the noninvasive test of choice for patients with suspected rotator cuff disease.