bluuebunny/crossref_metadata_2025 huggingface dataset:
Kinetics of Baseball Pitching with Implications About Injury Mechanisms
Authors: Fleisig Glenn S. , Andrews James R. , Dillman Charles J. , Escamilla Rafael F.
Published: June 2007

Elbow and shoulder kinetics for 26 highly skilled, healthy adult pitchers were calculated using high-speed motion analysis. Two critical instants were 1) shortly before the arm reached maximum external rotation, when 67 N-m of shoulder internal rotation torque and 64 N-m of elbow varus torque were generated, and 2) shortly after ball release, when 1090 N of shoulder com pressive force was produced. Inability to generate suf ficient elbow varus torque may result in medial tension, lateral compression, or posteromedial impingement in jury. At the glenohumeral joint, compressive force, joint laxity, and 380 N of anterior force during arm cocking can lead to anterior glenoid labral tear. Rapid internal rotation in combination with these forces can produce a grinding injury factor on the labrum. After ball release, 400 N of posterior force, 1090 N of compressive force, and 97 N-m of horizontal abduction torque are gener ated at the shoulder; contribution of rotator cuff muscles in generating these loads may result in cuff tensile fail ure. Horizontal adduction, internal rotation, and superior translation of the abducted humerus may cause sub acromial impingement. Tension in the biceps tendon, due to muscle contraction for both elbow flexion torque and shoulder compressive force, may tear the antero superior labrum.
Functional Anatomy of the Flexor Pronator Muscle Group in Relation to the Medial Collateral Ligament of the Elbow
Authors: Davidson Philip A. , Pink Marilyn , Perry Jacquelin , Jobe Frank W.
Published: June 2007

To describe the relationship of the pronator teres, flexor carpi radialis, flexor digitorum superficialis, and flexor carpi ulnaris muscles to the medial collateral ligament at 30°, 90°, and 120° of elbow flexion, we dissected 11 cadaveric specimens. The flexor carpi ulnaris muscle is the predominant musculotendinous unit overlying the medial collateral ligament in the majority of cases and is the only one at 120° of elbow flexion. The flexor digi torum superficialis muscle is the only other significant contributor. The medial collateral ligament is the pri mary stabilizer of the medial elbow with elbow flexion greater than 30°, as in throwing. The flexor carpi ulnaris muscle, because of its position directly over the medial collateral ligament, and the flexor digitorum superficialis muscle, with its near proximity and relatively large bulk, are the specific muscles best suited to provide medial elbow support. This is especially relevant to overhand throwing athletes who encounter extreme valgus force across the elbow during the cocking and acceleration phases of the throwing motion. Exercise and condition ing of the medial elbow musculature, specifically the flexor digitorum superficialis muscle and the flexor carpi ulnaris muscle, may prevent injury or assist in rehabili tation of medial elbow instability, especially in overhand throwing athletes.
Knee Extension and its Relationship to the Slope of the Intercondylar Roof
Authors: Howell Stephen M. , Barad Steven J.
Published: June 2007

This study determined that knee extension (range, -30° to 2°) and the slope of the intercondylar roof (range, 26° to 46°) vary widely between knees in both men and women. We found a weak relationship between knee extension and the slope of the intercondylar roof (r2 = 0.207); therefore, roof angle cannot be predicted by clinically measuring knee extension.

Clinical relevance: A knee with a given degree of ex tension can have a variety of different slopes to the in tercondylar roof. Knees with the combination of hyper extension and a vertically oriented slope to the intercondylar roof are "unforgiving" because they re quire a more posterior position for the tibial tunnel to avoid roof impingement and an extensive roofplasty. If the surgical objective is to minimize the extent of the roofplasty and avoid roof impingement, then consider ation should be given to customizing the placement of the tibial tunnel to account for variability in knee exten sion and roof angle when reconstructing the anterior cruciate ligament. Studies have shown that isometric graft placement can be achieved with this surgical approach.
Wrist Kinematics During Pitching
Authors: Pappas Arthur M. , Morgan William J. , Schulz Lisa A. , Diana Richard
Published: June 2007

A computerized hand and wrist motion analysis sys tem was modified to capture data at a rate of up to 1000 Hz. Using this system, wrist flexion and exten sion data were collected on five right-handed profes sional pitchers (75 pitches). A wrist position versus time graph was generated for each pitch. The pitch data produced a reproducible analysis of motion for the majority of the pitches regardless of pitcher. Based on the graphic display of data points, four phases of wrist motion during a pitch were identified. The first phase is the cocking phase, or the motion of the wrist as it moves into maximum extension. This is then followed by the most explosive phase, the ac celeration phase, which represents ball propulsion. At ball release, the wrist progresses through flexion and there is a consistent decrease in wrist velocity, known as the deceleration phase. Finally, there is the re covery phase, or the return of the wrist toward neutral. Average values for wrist range of motion, length of phase, and angular velocity (degrees per second) were calculated for each phase of the pitch. This study represents a major step toward quantifying mo tion of the wrist during a pitch. The ability to quantify this motion may prove valuable in the assessment of throwing athletes after injury and rehabilitation.
Effect on Knee Stability if Full Hyperextension is Restored Immediately After Autogenous Bone-Patellar Tendon-Bone Anterior Cruciate Ligament Reconstruction
Authors: Rubinstein Richard A. , Shelbourne K. Donald , VanMeter Charles D. , McCarroll John R. , Rettig Arthur C. , Gloyeske Robert L.
Published: June 2007

We sought to determine if knee stability after autog enous bone-patellar tendon-bone anterior cruciate liga ment reconstruction was adversely affected by obtain ing immediate full hyperextension. We selected patients based on degree of knee hyperextension. Group 1 (46 men and 51 women), with an average of 10° (range, 8° to 15°) hyperextension, was compared with the ran domly selected control Group 2 (70 men and 27 women), which had an average of 2° (range, 0° to 5°) hyperextension. The operative knee in both groups, which underwent similar reconstruction of the injured knee, achieved full passive extension equal to the non- involved knee during the immediate postoperative course. The average KT-1000 arthrometer manual maximum side-to-side differences were 2.4 mm for Group 1 and 2.1 mm for Group 2 (P = 0.13). Seventy- nine patients in Group 1 had KT-1000 arthrometer dif ferences of ≤3 mm as compared with 85 patients in Group 2. Fourteen patients in Group 1 had KT-1000 arthrometer differences of 4 or 5 mm as compared with eight patients in Group 2. Four patients in each group had KT-1000 arthrometer differences >5 mm. Evidence suggests that restoring and maintaining immediate full knee hyperextension after this type of reconstruction does not adversely affect the ultimate stability of the knee.
Achilles Tendon Ruptures
Authors: Mandelbaum Bert R. , Myerson Mark S. , Forster Robert
Published: June 2007

We prospectively treated 29 athletes who had Achilles tendon ruptures according to a functional rehabilitation protocol. The 25 male and 4 female patients had a mean age of 35 years (range, 19 to 56). The repair was per formed with a Krackow suture of No. 2 nonabsorbable polyfilament. Patients began range-of-motion exercises 72 hours after surgery, used a posterior splint for 2 weeks, and then began ambulation in a hinged orthosis. Six weeks after surgery, use of the orthosis was dis continued, full weightbearing was allowed, and progres sive resistance exercises were initiated. Isokinetic strength and endurance testing were performed at 3, 6, and 12 months after surgery. There were no reruptures. Two patients developed superficial wound infections that responded to debridement or local wound care. One patient suffered a pulmonary embolism. At 3 months' followup, isokinetic testing showed the mean functional deficits were 36% and 35% of the opposite leg at 60 and 120 deg/sec, respectively. By 6 months, the mean deficits were 2.9% and 2.3% at 60 and 120 deg/sec, respectively. All patients returned to preinjury activity levels at a mean of 4 months (range, 3 to 7) after repair. By 12 months, there were no significant differ ences in ankle motion, isokinetic strength, or endurance as compared with the uninvolved side.
The Role of the Cruciate and Posterolateral Ligaments in Stability of the Knee
Authors: Veltri Daniel M. , Deng Xiang-Hua , Torzilli Peter A. , Warren Russell F. , Maynard Michael J.
Published: June 2007

The role of the posterolateral and cruciate ligaments in restraining knee motion was studied in 11 human ca daveric knees. The posterolateral ligaments sectioned included the lateral collateral and arcuate ligaments, the popliteofibular ligament, and the popliteal tendon at tachment to the tibia. Combined sectioning of the an terior cruciate and posterolateral ligaments resulted in maximal increases in primary anterior and posterior translations at 30° of knee flexion. Primary varus, pri mary internal, and coupled external rotation also in creased and were maximal at 30° of knee flexion. Com bined sectioning of the posterior cruciate and posterolateral ligaments resulted in increased primary posterior translation, primary varus and external rota tion, and coupled external rotation at all angles of knee flexion. Examination of the knee at 30° and 90° of knee flexion can discriminate between combined posterior cruciate ligament and posterolateral injury and isolated posterolateral injury. The standard external rotation test performed at 30° of knee flexion may not be routinely reliable for detecting combined anterior cruciate and posterolateral ligament injury. However, measurements of primary anterior-posterior translation, primary varus rotation, and coupled external rotation may be used to detect combined anterior cruciate and posterolateral ligament injury.
Results of Arthroscopic Debridement of Glenoid Labral Tears
Authors: Martin Dale R. , Garth William P.
Published: June 2007

We studied the long-term results of a prospectively se lected group of 24 patients with 12 anteroinferior and 12 posterior glenoid labral lesions; all patients had func tional instability but none had ligamentous detachment. After arthroscopic debridement, patients involved in throwing sports were not allowed to return to full athletic activity until full strength of the external rotators was achieved and documented on isokinetic evaluation. Fol lowup was 36 to 72 months with an average of 48 months. Follow-up isokinetic evaluation revealed an av erage +4.4% and +8.6% concentric strength and -4.3% and -0.4% eccentric strength of the operated shoulder compared with the uninvolved shoulder at 90 and 180 deg/sec, respectively. Long-term good or ex cellent results were achieved in 21 patients, and 16 were functioning at their preinjury level of sports activi ties. Sixty-two percent of baseball pitchers were unim paired in pitching. The average University of California Los Angeles shoulder rating score was 31 of 35 (11 excellent, 10 good, and 3 poor) and the average Rowe- Zarins ratings scale was 85 of 100 (8 excellent, 13 good, and 3 poor). These results justify an initial arthroscopic debridement of anteroinferior or posterior labral flap tears rather than capsulorrhaphy when there is no gross instability or Bankart lesion.
The Effect of Nonablative Laser Energy on Joint Capsular Properties
Authors: Hayashi Kei , Markel Mark D. , Thabit George , Bogdanske John J. , Thielke Robert J.
Published: June 2007

To evaluate the effect of laser energy at nonablative levels on the mechanical properties of joint capsular tissues, we tested the femoropatellar joint capsules of 12 mature New Zealand White rabbits. Specimens were divided into three treatment groups (5, 10, and 15 watts) and one control group. All specimens were first non- destructively mechanically tested to determine stiffness and viscoelastic properties and then treated with laser energy or served as a control. Shrinkage was recorded and mechanical testing was repeated. The application of laser energy resulted in 9%, 26%, and 38% reduction in capsular tissue length for the 5, 10, and 15 watt groups, respectively. Tissue shrinkage was significantly and strongly correlated with energy density. Laser en ergy caused a significant decrease in tensile stiffness only in the 10 and 15 watt groups. Laser energy did not change the relaxation properties at any energy density. This study demonstrates that significant capsular shrinkage can be achieved with the application of non ablative laser energy without detrimental effects to the viscoelastic properties of the tissue; although at higher energy densities, laser energy did lessen capsular stiffness properties. The results of this study should be interpreted with caution until in vivo studies are performed.
Isolated Closure of Rotator Interval Defects for Shoulder Instability
Authors: Field Larry D. , Warren Russell F. , O'Brien Stephen J. , Altchek David W. , Wickiewicz Thomas L.
Published: June 2007

Fifteen patients noted at surgery to have an isolated defect in the rotator interval and no other pathologic abnormality underwent closure of the defect as an iso lated procedure for recurrent instability symptoms. In traoperative assessment of each of these shoulders after the closure demonstrated adequate stability, and no other stabilization procedures were performed. The average age of the patients was 24 years, and 10 of the 15 patients were women. Examination under anesthe sia revealed increased inferior translation in all patients, as illustrated by at least a 1 + sulcus sign. The rotator interval defect averaged 2.75 cm in width and 2.3 cm in height. The rotator interval defect edges were fresh ened and approximated (nine patients) or imbricated (six patients), depending on the anterior capsular laxity and the degree of glenohumeral joint translation pos sible. Followup averaged 3.3 years (range, 2.2 to 5.3), and all patients achieved either a good or excellent re sult using the American Shoulder and Elbow Surgeons evaluation scale and the Rowe rating scale. Although most patients with a defect in the rotator interval require a standard stabilization procedure as a supplement to closure of the defect, approximation or imbrication of the defect as an initial step at surgery may confer adequate stability in selected patients and obviate the need for formal capsular advancement.
Allograft Reconstruction of the Anterior and Posterior Cruciate Ligaments After Traumatic Knee Dislocation
Authors: Shapiro Matthew S. , Freedman Eric L.
Published: June 2007

Seven patients (average age, 26.3 years) with traumatic knee dislocations were retrospectively evaluated more than 2 years (average, 51 months) after having fresh- frozen allograft anterior and posterior cruciate ligament reconstructions. All patients were treated consecutively at an average of 9.6 days after injury. Two patients had arterial injuries and three patients had or developed common peroneal nerve palsy. Five patients had 20 additional injuries. All patients were enlisted in an early, aggressive physical therapy regimen with early pro tected weightbearing. Four patients required a manipu lation under anesthesia for arthrofibrosis at an average of 16.8 weeks postoperatively (range, 6 to 33 weeks). At followup, only one patient had significant pain, three patients had rare or occasional giving way, and all seven were able to return to school or to the workplace. The functional grading was excellent in three patients, good in three patients, and fair in one patient. No patient had a significant flexion contracture; the average flexion arc was 118° (range, 105° to 135°). Knee dislocation is a very traumatic injury, often resulting in a painful, dys functional knee. Anterior and posterior cruciate liga ment reconstructions in young, active patients can minimize pain and optimize functional outcome. Arthrofibrosis is a common occurrence in these pa tients, and manipulation under anesthesia is frequently required.
Ski Injury Statistics, 1982 to 1993, Jackson Hole Ski Resort
Authors: Warme Winston J. , Feagin John A. , King Paul , Lambert Kenneth L. , Cunningham R. Raymond
Published: June 2007

A retrospective analysis was conducted on injury statistics compiled over 12 seasons, from 1982 to 1993 (2.55 million skier-days), at a Wyoming ski resort. The population at risk was determined by ticket sales per year. A total of 9749 skiing injuries was indexed by anatomic region and se verity according to diagnosis on initial evaluation. Injury rates were then analyzed as a function of time. The injury rate remained constant at 3.7 injuries per 1000 skier-days during the 12 seasons. The rate of lower extremity to up per extremity injury decreased from 4:1 to 2:1 during the study period (P < 0.03). The ankle injury rate also de creased with time (P < 0.04). Ulnar collateral ligament sprains make up 7% of all injuries. Knee sprains in general account for 30% of all injuries. The incidence of anterior cruciate ligament tears increased as a function of time (P < 0.04) and accounted for 16% of all skiing injuries during the study period. The medial collateral ligament sprain was the most common injury, making up 18% of skiing injuries. Forty-seven snowboard injuries from the 1992 to 1993 season are also presented. Our injury statistics mir ror those currently reported in North America, except our data reflect a higher incidence of knee sprains.
Timing of Surgery in Acute Anterior Cruciate Ligament Tears on the Return of Quadriceps Muscle Strength After Reconstruction Using an Autogenous Patellar Tendon Graft
Authors: Shelbourne K. Donald , Foulk Douglas A.
Published: June 2007

To determine if patients who delayed anterior cruciate ligament reconstruction until a convenient time re gained quadriceps muscle strength allowing them to re turn to sports participation at a different rate than pa tients who had early surgery for anterior cruciate ligament reconstruction, we studied 143 patients who had the same surgical procedure and postoperative re habilitation program. Group I delayed surgery at a mean of 40 days after injury; Group II had early surgery at a mean of 11 days after injury. Statistically, Group I pa tients had significantly better mean quadriceps muscle strength at 2 months (P = 0.017) and at 4 months (P = 0.0055) postoperatively. At least 65% quadriceps muscle strength was achieved by 40 of the 50 patients (80%) tested in Group I at 2 months, allowing the pa tients to progress to sport-specific rehabilitation. Only 35 of the 66 patients (53%) tested in Group II were able to progress toward sports activities at 2 months. By 6 months, 29 of the 40 patients (73%) tested in Group I compared with 27 of the 58 patients (47%) tested in Group II had 80% quadriceps muscle strength. This study demonstrates that the return of quadriceps muscle strength was faster for our patients who delayed anterior cruciate ligament reconstruction than for our patients who had early reconstruction. Thus, despite delaying their early reconstructions, Group I was able to progress sooner from the date of surgery to sport- specific rehabilitation.
Knee Injury Patterns Among Men and Women in Collegiate Basketball and Soccer
Authors: Arendt Elizabeth , Dick Randall
Published: June 2007

Women's participation in intercollegiate athletics has increased dramatically in recent years. Greater par ticipation has increased awareness of health and medical issues specific to the female athlete. Some reports have noted a higher susceptibility to knee in jury, specifically injuries to the anterior cruciate liga ment, in female athletes as compared with their male counterparts. We performed a 5-year evaluation of anterior cruciate ligament injuries in collegiate men's and women's soccer and basketball programs using the National College Athletic Association Injury Sur veillance System. Results showed significantly higher anterior cruciate ligament injury rates in both female sports compared with the male sports. Non contact mechanisms were the primary cause of an terior cruciate ligament injury in both female sports. Possible causative factors for this increase in anterior cruciate ligament injuries among women may be ex trinsic (body movement, muscular strength, shoe- surface interface, and skill level) or intrinsic (joint lax ity, limb alignment, notch dimensions, and ligament size).
Immunohistologic Analysis of Synovium in Infrapatellar Fat Pad After Anterior Cruciate Ligament Injury
Authors: Murakami Shunichi , Muneta Takeshi , Furuya Kohtaro , Saito Ichiro , Miyasaka Nobuyuki , Yamamoto Haruyasu
Published: June 2007

To clarify the natural course of synovitis after anterior cru ciate ligament injury, we took synovial tissues at various periods after injury and analyzed them immunohistologi cally. Twelve patients with isolated anterior cruciate liga ment injuries participated in the study. Inflammation in tensity was graded semiquantitatively based on the following parameters: synovial lining cell depth, synovial hyperplasia, vascular hyperplasia, lymphocyte infiltration, and the expression of cell adhesion molecules. The ex pression of fibrogenic cytokines and the degree of fibrosis were also investigated to elucidate the mechanisms of ar throfibrosis. The results demonstrated that synovitis in the infrapatellar fat pad subsides within 3 months after injury with the progression of fibrosis. Fibrogenic cytokines, platelet-derived growth factor and transforming growth factor-β, were detected at fibrotic sites, suggesting their involvement in arthrofibrosis. An increased incidence of arthrofibrosis recently has been recognized to occur when anterior cruciate ligament reconstruction is performed within several weeks after injury. We speculate that when anterior cruciate ligament reconstruction is performed dur ing the stage of acute synovitis, the operation may further promote the synovitis, accelerating the arthrofibrotic re action. Waiting to perform the anterior cruciate ligament reconstruction until the synovitis resolves may possibly decrease the motion problems seen postoperatively.
The Role of the Popliteofibular Ligament in Stability of the Human Knee
Authors: Veltri Daniel M. , Xiang-Hua Deng  , Torzilli Peter A. , Maynard Michael J. , Warren Russell F.
Published: June 2007

The popliteal tendon has a significant attachment to the fibula, the popliteofibular ligament. The role of this ligament in knee stability has not been determined. In this study we used selective cutting techniques to measure the static contribution of the popliteal tendon attachments to the tibia and the popliteofibular liga ment for stability of the knee. Sectioning of all the posterolateral structures except the popliteal tendon attachments to the tibia or the popliteofibular ligament resulted in increased primary posterior translation, va rus rotation, external rotation, and coupled external rotation. Although statistically significant, these in creases were small. Sectioning of all the posterolateral structures resulted in larger increases in primary pos terior translation, varus rotation, external rotation, and coupled external rotation. Our data indicate that the popliteal tendon attachments to the tibia and the pop liteofibular ligament are important in resisting posterior translation and varus and external rotation. If an iso lated injury to the posterolateral structures occurs, an atomic reconstruction of the major ligaments that re strain posterior translation and varus and external rotation may provide the best functional result. Recon struction for isolated posterolateral instability should include anatomic attachment of the popliteal tendon to the tibia and the popliteofibular ligament.
The Effect of Ambient Temperature on the Shoe-Surface interface Release Coefficient
Authors: Torg Joseph S. , Stilwell Gary , Rogers Kenneth
Published: June 2007

Previous studies of the shoe-surface interface corre lated foot fixation with cleat length, configuration, and material composition as well as turf type and surface conditions. Our study examined the effect of tempera ture on the rotational torsion resistance of artificial turf football shoes. Five football shoe models, a flat-soled basketball-style turf shoe, a natural grass soccer-style shoe, and three multistudded turf shoes, were studied on dry AstroTurf at five temperatures (range, 52°F to 110°F). An assay device, a prosthetic foot mounted on a loaded stainless steel shaft, was used to determine the force necessary to release a shoe from the turf's surface. We used a torque wrench to apply a rotational force so that each shoe was pivoted counterclockwise through an arc of 60°. Our results indicated that re lease coefficients differ within and among the shoe models at various turf temperatures. We also found that an increase in turf temperature, in combination with cleat characteristics, affects shoe-surface inter face friction and potentially places the athlete's knee and ankle at risk of injury. Based on an established risk criterion, which correlated shoe-surface interface com binations in the laboratory with documented clinical occurrences, only the flat-soled basketball-style turf shoe could be designated "safe" or "probably safe" at all five temperatures.
Diagnosis of Glenoid Labral Tears
Authors: Liu Stephen H. , Henry Mark H. , Nuccion Steven , Shapiro Matthew S. , Dorey Fred
Published: June 2007

We studied 54 patients with shoulder pain secondary to anterior instability or glenoid labral tears refractory to 6 months of conservative management with no evi dence of rotator cuff lesions. All patients had sufficient preoperative clinical data, magnetic resonance imag ing, and shoulder arthroscopy results for analysis. The ability to predict the presence of a glenoid labral tear by physical examination was compared with that of mag netic resonance imaging (conventional and arthro gram) and confirmed with arthroscopy. There were 37 men and 17 women (average age, 34 years) in the study group. Of this group, 64% were throwing athletes and 61% recalled specific traumatic events. Clinical assessment included history with specific attention to pain with overhead activities, clicking, and instances of shoulder instability. Physical examination included the apprehension, relocation, load and shift, inferior sulcus sign, and crank tests. Shoulder arthroscopy confirmed labral tears in 41 patients (76%). Magnetic resonance imaging produced a sensitivity of 59% and a specificity of 85%. Physical examination yielded a sensitivity of 90% and a specificity of 85%. Physical examination is more accurate in predicting glenoid labral tears than magnetic resonance imaging. In this era of cost con tainment, completing the diagnostic workup in the clinic without expensive ancillary studies allows the patient's care to proceed in the most timely and economic fashion.
The Superiority of Magnetic Resonance Imaging in Differentiating the Cause of Hip Pain in Endurance Athletes
Authors: Shin Alexander Y. , Morin William D. , Germany John D. , Jones Steven B. , Lapinsky Anthony S.
Published: June 2007

The accuracy of magnetic resonance imaging of the hip was prospectively evaluated in 19 military subjects engaged in endurance training. These patients had hip pain, negative radiographs, and radionuclide bone scans consistent with femoral neck stress fracture. Twenty-two hips were identified as positive for femoral neck stress fracture by bone scan. Each patient under went magnetic resonance imaging and 6-week fol low-up plain radiographs of the hips. Magnetic reso nance imaging studies differentiated femoral neck stress fractures from a synovial pit, iliopsoas muscle tear, iliopsoas tendinitis, obturator externus tendinitis, avascular necrosis of the femoral head, and a unicam eral bone cyst. The follow-up radiographs were used to verify the diagnosis of stress fracture. The radiographs showed healing callus in patients with stress fractures. Patients with diagnoses other than stress fractures had no changes on follow-up radiographs. Magnetic reso nance imaging studies were as sensitive and much more specific than bone scan in determining the cause of hip pain. Radionuclide bone scan had an accuracy of 68% for femoral neck stress fractures with 32% false-positive results; MRI was 100% accurate. Mag netic resonance imaging proved to be superior to ra dionuclide bone scanning in providing an early and accurate diagnostic tool that aided in the differential diagnosis of hip pain in the young endurance athlete.
Acute and Chronic Brain Injury in United States National Team Soccer Players
Authors: Jordan Sheldon E. , Green Gary A. , Galanty Harry L. , Mandelbaum Bert R. , Jabour Bradley A.
Published: June 2007

We designed a study to determine whether chronic encephalopathy occurs in elite, active soccer players resulting from repetitive heading of the soccer ball. Studies have suggested that the cumulative effects of heading a ball can cause a chronic brain syndrome similar to dementia pugilistica, which is seen in profes sional boxers. Twenty of 25 members of the U.S. Men's National Soccer Team training camp (average age, 24.9; average years of soccer, 17.7), who com pleted a questionnaire on head injury symptoms and had magnetic resonance imaging of the brain, were compared with 20 age-matched male elite track ath letes. The soccer players were surveyed about playing position, teams, number of headers, acute head inju ries, and years of playing experience. An exposure index to headers was developed to assess a dose- response effect of chronic heading. The soccer and track groups were questioned regarding alcohol use and history of acute head traumas. Questionnaire anal ysis and magnetic resonance imaging demonstrated no statistical differences between the two groups. Among the soccer players, symptoms and magnetic resonance imaging findings did not correlate with age, years of play, exposure index results, or number of headers. However, reported head injury symptoms, especially in soccer players, correlated with histories of prior acute head injuries ( r = 0.63). These findings suggest that any evidence of encephalopathy in soccer players relates more to acute head injuries received playing soccer than from repetitive heading.
Factors Related to Quadriplegia in Football and the Implications for Intervention Strategies
Authors: Bishop Patrick J.
Published: June 2007

Axial compressive loading, the principal cause of spi nal cord quadriplegia in American football, is produced when a player is forcibly struck on the crown of the helmet. This impact subjects the small cervical verte brae to a large compressive force that often produces stress that exceeds the failure limit of the spine. Sev eral factors influence the outcome in axial collisions, including the available kinetic energy, the displace ment needed to dissipate the energy, and the end conditions of the collision (i.e., the position of the head). Effective intervention of this catastrophic injury requires the melding of information from the fields of biomechanics and epidemiology. From a biomechani cal perspective, neck loading should be kept at a level that is below the failure limit of the cervical spine. The epidemiologic rate at which these injuries develop among football players suggests that cervical quadri plegia is rare. Thus, protective devices intended to lower the forces on the cervical spine may not succeed in dramatically reducing the incidence of this injury. Because this injury is rare, it is important to consider that introducing new protective equipment, intended for intervention of one problem (i.e., cervical quadriplegia), may lead to other injuries.
The Effect of Partial Meniscectomy on the Long-Term Prognosis of Knees with Localized, Severe Chondral Damage
Authors: Maletius Wolfgang , Messner Karola
Published: June 2007

We retrospectively matched 42 patients with unilateral chondral damage in the weightbearing zone of one knee compartment according to sex, age, location of chondral damage, and follow-up time. Two groups of 21 patients were formed. One group had chondral damage only. The other group had chondral damage and a meniscal tear treated with partial meniscectomy. After 12 to 15 years, all patients were reexamined. Twenty-nine percent ( N = 6) of the patients who had a partial meniscectomy needed repeat meniscal surgery during followup. No patients with isolated chondral damage developed meniscal symptoms, and only three patients underwent minor surgeries ( P < 0.02). At the follow-up evaluation, both groups had similar knee function with a mean Lysholm score of 87 points. However, most patients had reduced their sports ac tivities from competitive individual sports before injury to noncompetitive physical fitness exercise at followup. At the roentgenologic examination, patients who had partial meniscectomies had more severe roentgeno logic signs of osteoarthritis than patients who had chondral damage only ( P < 0.03). Meniscectomy, va rus knee alignment at the follow-up evaluation ( P < 0.04), and age older than 30 years ( P < 0.04) at the time of the operation were associated with a higher incidence of osteoarthritis.
The Role of the Acromioclavicular Ligaments and the Effect of Distal Clavicle Resection
Authors: Branch Thomas P. , Burdette Hillary L. , Shahriari Abtin S. , Carter Fred M. , Hutton William C.
Published: June 2007

To determine the role of the acromioclavicular liga ments in controlling scapular rotation about the distal clavicle and the effects of distal clavicle resection, we used 13 fresh shoulders consisting of the clavicle, acromioclavicular ligaments, coracoclavicular liga ments, and scapula. The range of motion was mea sured using a specially designed goniometer for each of the three orthogonal axes of rotation of the scapula with reference to the clavicle: anterior-posterior axial rotation, protraction-retraction, and abduction-adduc tion. We did two experiments involving sequential sec tioning. Range of motion was measured in the intact shoulder and after each sectioning cut. The order of sectioning in Experiment 1 (six shoulders) was 1) the inferior acromioclavicular ligament, 2) removal of 5 mm of the distal clavicle, and 3) the superior acromiocla vicular ligament. In Experiment 2 (seven shoulders) the order was 1) the superior acromioclavicular ligament, 2) removal of 5 mm of the distal clavicle, and 3) the inferior acromioclavicular ligament. The most important results were 1) only 5 mm of the distal clavicle needs to be resected to ensure that no bone-to-bone contact occurs in rotation postoperatively and 2) there was no difference in the end result (for range of motion in any of the three axes) whether the inferior acromioclavicu lar ligament or the superior acromioclavicular ligament was cut before removal of 5 mm of the distal clavicle.
Comparison of Failure Strength Between Metallic and Absorbable Interference Screws
Authors: Pena Fernando , Grøntvedt Torbjorn , Brown Greg A. , Aune Arne K. , Engebretsen Lars
Published: June 2007

Because of the good initial fixation strength of interfer ence screws used in anterior cruciate ligament recon struction, metal interference screws have become the standard method for fixation of bone-patellar tendon- bone grafts. To avoid some of the complications with metal screws, a bioabsorbable interference screw was developed. Data on fixation strength in older human cadavers indicate a similar failure strength between bioabsorbable and metal screws. We studied the fail ure mechanisms, insertion torques, and fixation strengths of absorbable and metal interference screws in cadaveric knees from young and middle-aged do nors. With identical gap and screw size, the mean insertion torque for the metal screws (mean, 1.5 N-m; SD, 0.8) was significantly higher than for the absorb able screws (mean, 0.3 N-m; SD, 0.19). The mean failure load for the metal screws (mean 640 N; SD, 201) was also significantly higher than for the absorb able screws (mean, 418 N; SD, 118).
Achieving Full Range Of Motion After Anterior Cruciate Ligament Reconstruction
Authors: Majors Roy A. , Woodfin Blane
Published: June 2007

A review of 119 consecutive anterior cruciate ligament reconstructions showed that the time from injury to surgery (early versus delayed) did not make a differ ence in obtaining full range of motion. Only patients with late surgery had a slight decrease in range of motion. Followup data were obtained for 111 recon structions. Twenty-one were early surgeries (1 to 14 days), 22 were delayed surgeries (15 to 28 days), and 68 were late surgeries (more than 28 days). The pa tients involved in the 21 early surgeries obtained 0° of knee extension or better and 135° of knee flexion or better. The patients involved in the 22 delayed recon structions reached 0° of knee extension or better and 135° of flexion or better. Among the patients with the 68 late surgeries, 93% of the knees reached 0° of extension or better and all reached at least 135° of flexion. The five patients who did not achieve full knee extension had extension loses less than 4°. All 111 reconstructions were determined stable when full range of motion was achieved based on clinical exam ination, which included the Lachman test, anterior drawer test, pivot shift, and KT-1000 arthrometer when appropriate.
Neuromuscular Performance Characteristics in Elite Female Athletes
Authors: Huston Laura J. , Wojtys Edward M.
Published: June 2007

The purpose of this research was to identify possible predisposing neuromuscular factors for knee injuries, particularly anterior cruciate ligament tears in female athletes by investigating anterior knee laxity, lower extremity muscle strength, endurance, muscle reaction time, and muscle recruitment order in response to anterior tibial translation. We recruited four subject groups: elite female ( N = 40) and male ( N = 60) athletes and sex-matched nonathletic controls ( N = 40). All participants underwent a subjective evaluation of knee function, arthrometer measurement of anterior tibial translation, isokinetic dynamometer strength and endurance tests at 60 and 240 deg/sec, and anterior tibial translation stress tests. Dynamic stress testing of muscles demonstrated less anterior tibial translation in the knees of the athletes (both men and women) com pared with the nonathletic controls. Female athletes and controls demonstrated more anterior tibial laxity than their male counterparts and significantly less mus cle strength and endurance. Compared with the male athletes, the female athletes took significantly longer to generate maximum hamstring muscle torque during isokinetic testing. Although no significant differences were found in either spinal or cortical muscle reaction times, the muscle recruitment order in some female athletes was markedly different. The female athletes appeared to rely more on their quadriceps muscles in response to anterior tibial translation; the three other test groups relied more on their hamstring muscles for initial knee stabilization.
The Effects of Knee Reconstruction on Combined Anterior Cruciate Ligament and Anterolateral Capsular Deficiencies
Authors: Samuelson Matthew , Draganich Louis F. , Xiadong Zhou  , Krumins Peter , Reider Bruce
Published: June 2007

We tested the effect of intraarticular reconstructions of the anterior cruciate ligament alone and in combination with extraarticular reconstructions in 10 cadaveric knees. These knees had anterior cruciate ligament deficiency alone or in combination with anterolateral capsuloligamentous deficiencies. In the knees with combined injury, intraarticular reconstruction returned anterior stability to levels not significantly different from levels found for the knees deficient in the anterior cruciate ligament alone and treated with this proce dure. After intraarticular reconstruction, rotational sta bility of the knee with combined injuries failed to return to the levels seen in the knee with isolated anterior cruciate ligament deficiencies that underwent the same treatment. When a tenodesis with either 0 N or 22 N of tension was added to the intraarticular reconstruction in the knee with combined injuries, we found that ex cessive internal rotation significantly decreased at all angles of flexion, except at full extension with 0 N of tension. In addition, the extraarticular reconstruction with 22 N of tension in the tenodesis overconstrained the knee in internal rotation between 30° and 90° of knee flexion. The tenodesis with 0 N of tension over constrained the knee at only 60° and 90° of flexion. These results suggest extraarticular reconstruction as an adjunct to the intraarticular operation for the knee with anterior cruciate ligament and anterolateral struc tural injuries. The results also suggest that the surgeon can affect anterior and rotational laxity by adjusting the tension in the tenodesis.
Is Prevention of Sports Injuries a Realistic Goal?
Authors: Twellaar Mascha , Verstappen Frans T. J. , Huson Anthony
Published: June 2007

To assess the reliability of injury registration and to determine the incidence of injury in intramural (pro gram of the institution) and extramural (leisure time) sports activities, we prospectively recorded information on sports injuries for 4 years in a group of 136 physical education students. Registration forms were com pleted every 3 weeks, and data on medical consulta tions were recorded. During the last year, we asked 59 students to recall all injuries sustained to establish the reliability of retrospective injury registration. In the pro spective study, 525 sports injuries were recorded: 58% during intramural activities and 42% during extramural. The incident rate per 1000 hours of intramural activities (1.26) was significantly lower than that for extramural activities (1.77). A gradual decline in response rate from 98.4% the 1st year to 87.7% in the final year indicated a decreasing compliance during the study period. Eighteen percent of all injuries with recorded medical consultations were not reported by the stu dents. At the retrospective injury registration in the final year of the study, students had forgotten 54% of the recorded injuries and 50 injuries (20% of all recorded injuries) were mentioned that had not been recorded during the previous years. We conclude that, even in a well-supervised population, prospective injury registra tion is not complete, and the reliability of retrospective injury registration is even poorer.
Dynamic Electromyographic Analysis of Trunk Musculature in Professional Golfers
Authors: Watkins Robert G. , Uppal Gurvinder S. , Perry Jacqueline , Pink Marilyn , Dinsay Jocylane M.
Published: June 2007

Using dynamic surface electrode electromyography, we evaluated muscle activity in 13 male professional golfers during the golf swing. Surface electrodes were used to record the level of muscle activity in the right abdominal oblique, left abdominal oblique, right glu teus maximus, left gluteus maximus, right erector spi nae, left erector spinae, upper rectus abdominis, and lower rectus abdominis muscles during the golfer's swing. These signals were synchronized electronically with photographic images of the various phases of the golf swing; the images were recorded in slow motion through motion picture photography. The golf swing was divided into five phases: take away, forward swing, acceleration, early follow-through, and late fol low-through. Despite individual differences among the subjects' swings, we observed reproducible patterns of trunk muscle activity throughout all phases of the golf swing. Our findings demonstrate the importance of the trunk muscles in stabilizing and controlling the loading response for maximal power and accuracy in the golf er's swing. This study provides a basis for developing a rehabilitation program for golfers that stresses strengthening of the trunk muscles and coordination exercises.
Increased Tibial Translation After Partial Sectioning of the Anterior Cruciate Ligament
Authors: Hole Robert L. , Lintner David M. , Kamaric Emir , Moseley J. Bruce
Published: June 2007

We measured changes in anterior translation of the tibia with sequential sectioning of the bundles of the anterior cruciate ligament and correlated these changes with the clinical examination. Six fresh cadav eric lower extremities were examined by three experi enced knee surgeons in a masked fashion with the anterior cruciate ligament intact and after sectioning of the posterolateral bundle, the posterolateral bundle and 50% of the anteromedial bundle, and the entire ligament. Lachman, anterior drawer, and lateral pivot shift tests were performed. Both KT-1000 arthrometer testing (30 pounds) and biplanar radiography demon strated progressive increases in anterior translation with incremental sectioning of the anterior cruciate lig ament. However, significant ( P < 0.05) increases in translation were found only after sectioning both the posterolateral bundle and half of the anteromedial bun dle and after complete sectioning of the anterior cruci ate ligament. The examiners were accurate in their interpretation of the status of the anterior cruciate lig ament in 89% of the intact specimens and 80% of completely sectioned ligaments. Only 11 % of the ex aminations correctly diagnosed the anterior cruciate ligament as partially cut when the posterolateral bundle was sectioned. A soft end point to the Lachman exam ination was noted only after cutting at least 75% of the ligament, but was not always present. Clinical evalua tion is accurate in defining intact and completely sec tioned anterior cruciate ligaments. However, it is un able to differentiate a sectioned posterolateral bundle from an intact anterior cruciate ligament, or a 75% sectioned ligament from a completely sectioned liga ment. The clinical diagnosis of a partial tear of the anterior cruciate ligament is more likely to represent a complete or "functionally complete" tear.
Knee Joint Dynamics Predict Patellar Tendinitis in Elite Volleyball Players
Authors: Richards David P. , Ajemian Stanley V. , Wiley J. Preston , Zernicke Ronald F.
Published: June 2007

We quantified the lower extremity dynamics developed during the volleyball spike and block jumps to find out if predictive relations exist between jump dynamics and patellar tendinitis. Lower extremity movement biome chanics were analyzed for 10 members of the 1994 Canadian Men's National Volleyball Team (all right- handed hitters). Based on physical examination, 3 of the 10 players had patellar tendon pain associated with patellar tendinitis at the time of testing. In masked biomechanical and logistic regression analyses, we discovered that the vertical ground-reaction force dur ing the take-off phase of both spike and block jumps was a significant predictor of patellar tendinitis—cor rectly predicting the presence or absence of patellar tendinitis in 8 of 10 players. Deepest knee flexion angle (during landing from the spike jump) predicted 10 of 10 cases correctly for the left knee. The external tibial torsional moment (during the takeoff for the right knee with the spike jump and for the left knee with the block jump) was also a significant predictor of tendinitis. In these players, the likelihood of patellar tendon pain was significantly related to high forces and rates of loading in the knee extensor mechanism, combined with large external tibial torsional moments and deep knee flexion angles.