bluuebunny/crossref_metadata_2025 huggingface dataset:
An evaluation of football helmets under impact conditions
Authors: Bishop Patrick J. , Norman Robert W. , Kozey John W.
Published: June 2007

The impact attenuating characteristics of a sample of 81 football helmets used in competitive high school programs were determined using a Hodgson-Wayne State University (WSU) headform and a modified Na tional Operating Committee on Standards for Athletic Equipment (NOCSAE) test protocol. The helmets, clas sified by liner type as suspension (37), padded-suspen sion (22), and padded (22) had been in use for 6 to 8 years. Each was subjected to two consecutive right rear boss impacts from a drop height of 1.5 m, onto a rigid anvil covered with a 45 durometer hardness rubber pad. Analogue signals from a triaxial accelerometer located at the center of gravity of the headform were analogue to digital (A/D) converted at 6060.6 Hz and processed on a Hewlett Packard 9845B minicomputer to yield a resultant acceleration-time curve from which peak acceleration (gpeak) and the Gadd Severity Index (GSI) were determined. The mean gpeak was 205 g for helmets with suspension liners, 165 g for helmets with padded-suspension liners, and 156 g for helmets with padded liners. Twenty-four suspension helmets and five padded or padded-suspension helmets had GSI values greater than 1200. Using a criterion of GSl1500 the failure rate for suspension helmets was 19% compared to 2% for padded and padded-suspension helmets combined. If the criterion chosen was GSl1200 the failure rate for suspension helmets was 65% as op posed to 11 % for the padded and padded-suspension helmets combined. Suspension helmets are decidedly inferior under impact conditions to the padded and padded-suspension helmets.
Women Midshipmen in Sports
Authors: Cox Jay S. , Lenz Heinz W.
Published: June 2007

This is a study of the physical performance and injury rate for seven classes of women midshipmen at the United States Naval Academy. Women comprise only 6.2% of the brigade of midshipmen, but men and women live in the same dormitory, undergo the same physical training and fitness tests, study the same academic curriculum, and live in an environment where performance and activities can be constantly moni tored. The required number of hours of physical edu cation are the same for men and women.

The conclusions from this study are: (1) women midshipmen continue to improve their fitness level more rapidly than men; (2) while some disparities in perform ance are correctly attributed to physiological differ ences, many of the present disparities should be attrib uted to societal conditions; (3) should physical perform ance requirements ever become the same, women will have to work harder than men to achieve the same standards because of the physiological differences; (4) women continue to seek medical attention for stress- related problems (i.e., shin splints, stress fractures) more often than men, but do so less often as they become acclimated to the active life of the Naval Acad emy ; (5) women midshipmen have the same number of serious injuries as men, and in some sports are more susceptible to certain types of injuries.
Stress fracture of the humerus
Authors: Allen Murray E.
Published: June 2007

A 13-year-old male Little League pitcher sustained a displaced spiral fracture of the right midhumerus while in midpitch. Deep ache prodrome symptoms in the midhumerus at rest and during pitching occurred during the preceeding week, suggestive of a stress fracture that later completed to an overt fracture during the added stress of a forceful side-arm curve ball pitch, his specialty. Osteonal remodeling in stress fractures is discussed.
Decreasing the incidence of recurrence of first time anterior shoulder dislocations with rehabilitation
Authors: Aronen John G. , Regan Kevin
Published: June 2007

Studies of adolescent and young adult males sustaining primary anterior shoulder dislocations reveal the like lihood of recurrence to be virtually always above 50% and as high as 79% to 94%. Common among these investigations is the lack of a specific, rigidly adhered to rehabilitation program.

During a 3½ year period, 20 midshipmen at the United States Naval Academy sustained primary anterior shoulder dislocations. All participated in an identical treatment regimen which included a restrengthening program emphasizing the muscles of internal rotation and adduction, plus rigid restrictions of activities until the goals of their rehabilitation program were satisfied. Exercises progressed from isometrics through isoton ics and isokinetics. Goals included return to full active, unrestricted duty and athletic participation which in cluded participation in the sport that resulted in the original dislocation. Patients were followed for an av erage of 35.8 months (with a range of 17 to 45 months). During the period of study there were five recurrences (25%). A success rate of 75% would suggest that adherence to a specific, aggressive postdislocation re habilitation program, plus rigid restrictions of activities until the goals of the program are satisfied, can sub stantially improve the likelihood of a full return to activity without recurrent shoulder dislocation.
Osteochondrosis of the humeral capitellum
Authors: Singer Kenneth M. , Roy Steven P.
Published: June 2007

Seven cases of osteochondrosis of the capitellum oc curring in five high performance female gymnasts be tween the ages of 11 and 13 are presented. Two of the patients were treated by surgical excision of the loose osteochondral fragment in three elbows. Four of the five gymnasts, including the two who underwent surgical treatment, were able to return to full workouts without recurrence of symptoms within the 3 year followup.

All conditions in gymnasts were detected after symp toms had presented. A survey of 37 actively competing gymnasts at a nationally known gymnastics academy was performed, including a detailed history and physical examination and radiographic examination. No other cases of osteochondrosis were detected.

It was postulated that this condition represents a lateral compression injury because of repetitive valgus overload. Investigation of the capitellar blood supply indicates that the common factors in osteochondrosis of the capitellum are repetitive or prolonged trauma to a vulnerable epiphysis on a basis of vascular interrup tion. Gymnastics maneuvers require forceful weight- bearing through the upper extremities.

Medical personnel and coaches associated with gym nastics need to be aware of the condition of osteo chondrosis of the capitellum so that any gymnast who presents with a painful, tender, swollen or locked elbow is appropriately investigated and treated.
Contractile properties of slow and fast muscle following tourniquet ischemia
Authors: Gardner Vance O. , Caiozzo Vincent J. , Long Susan T. , Stoffel John , McMaster William C. , Prietto Carlos A.
Published: June 2007

Tourniquet application is commonly used during sur gery on an extremity to create a bloodless field. Inves tigations have focused on the ultrastructural, histo chemical, and biochemical effects of tourniquet isch emia on muscle. Few studies, however, have examined the influence of tourniquet ischemia on the contractile properties of muscle. The purpose of this study was not only to examine this latter consideration, but also to determine whether slow and fast muscles exhibit a differential response. In adult male guinea pigs, the plantaris and soleus muscles of control (N = 5) and experimental legs (N = 5) were tested for time-peak- tension (TPT), one-half relaxation time (½RT), maximal twitch tension (Pt), and maximal tetanic tension (Po). The experimental leg was subjected to a 2 hour tour niquet which was placed around the thigh. Muscles of this leg were tested following a 2 hour recovery period. In three of the five animals, no response could be elicited from either the plantaris or soleus muscles of the experimental leg. In those instances where the experimental muscles were capable of generating force, the plantaris was clearly more effected. While tension production in the soleus was reduced by ap proximately 55%, the plantaris exhibited approximately a 90% decrease in tension output. Furthermore, both TPT and ½RT demonstrated consistent changes. These results indicate that the contractile properties of both the soleus and plantaris are dramatically effected by a 2 hour tourniquet. They further suggest that there may be a differential response based upon fiber type.
Torque-velocity relationships of the knee extensor and flexor muscles in individuals sustaining injuries of the anterior cruciate ligament
Authors: Murray Sarah M. , Warren Russell F. , Otis James C. , Kroll Michael , Wickiewicz Thomas L.
Published: June 2007

Muscle deficits in 58 patients with chronic anterior cruciate ligament (ACL) insufficiency were evaluated after completion of a 6 month rehabilitation program. Quadriceps and hamstring torques were measured on a modified Cybex II isokinetic dynamometer. Twenty- nine of our patients were tested just prior to undergoing ACL reconstruction, and patients who were continuing to tolerate their conditions served as controls.

For the surgical group, significant quadriceps deficits (P < 0.01) were found for all speeds and at both the 30 and 60° positions. The nonsurgical group had sig nificant deficits at the 30° position at 180°/sec, and at 60° for the 0°/sec and 30°/sec. However, in comparing the two groups no significant differences were noted.

Regarding hamstring deficits in the surgical group, significant deficits were seen only at 30° of flexion at 180°/sec. The nonsurgical group had similar deficits.

Of interest was the observation that the ham string:quadriceps (H:Q) ratio was found to be both speed-position dependent.

Overall, no correlation was found between the pres ence of strength deficits following a rehabilitation pro gram and the need for surgery.
Diagnosis of cruciate ligament injury using single contrast arthrography
Authors: Reider Bruce , Clancy William , Langer Leonard O.
Published: June 2007

To evaluate the accuracy of arthrography for assessing the status of the anterior cruciate ligament (ACL), 212 arthrograms from 212 knees in 205 consecutive pa tients undergoing single contrast arthrography and sub sequent arthroscopy or arthrotomy were reviewed. Cri teria for evaluation of the ACL included the clarity of its radiographic appearance as well as the anterior laxity of the knee as seen on manual stress views. Of the 111 knees having intact ACLs at surgery, 98 (88%) were evaluated correctly by arthrography. Of the 101 knees having a damaged ACL, 85 were read as torn or attenuated on the arthrogram. When the torn and at tenuated ligaments were considered separately, accu racy was decreased. Of the 87 ligaments actually torn, 68 (78%) were read as torn and 9 (10%) as attenuated. Of the 14 actually attenuated, 5 (36%) were read as attenuated and 3 (21 %) as torn. Of 114 arthrograms read as intact, 98 (86%) were correct. Of 77 arthro grams read as torn, 68 (88%), were correct. Of 21 arthrograms read as attenuated, 5 (24%) were correct. Of 114 torn medial menisci, 112 (98%) were correctly diagnosed, as were 38 (69%) of 55 torn lateral menisci. Sixteen of the 17 missed lateral meniscus tears were in knees with torn medial menisci. Single contrast ar thrography is, therefore, highly accurate in distinguish ing intact from damaged ACLs. The distinction between torn and attenuated ligaments, however, is not valua ble.
An unusual cause of back pain in a young athlete
Authors: Clark Andrew , Stanish William D.
Published: June 2007

Back pain in the young athlete is a common problem seen in many sport medicine clinics. Not only can this be a difficult problem for the physician to manage (due to inability to pinpoint the pathology), but it is a frustrating expenence for the athlete, unable to compete or train effectively. The sport medicine physician must, therefore, always be alert and ob sessed with obtaining a precise diagnosis to be followed by specific treatment.

When presented with the adolescent athlete suffering with back pain, one must consider the full gamut of diagnostic possibilities. Mechanical or spondylogenic causes are most common; however, potentially more serious infective, meta bolic, and neoplastic conditions should also be considered.
Three-dimensional cinematographic analysis of water polo throwing in elite performers
Authors: Whiting William C. , Puffer James C. , Finerman Gerald A. , Gregor Robert J. , Maletis Greg B.
Published: June 2007

Thirteen members of the United States Men's Water Polo Team were filmed using two synchronized cam eras while shooting at a goal. Three-dimensional (3D) coordinates of the throwers' shoulder, elbow, wrist, and the ball were used to estimate elbow angle, elbow angular velocity, and ball velocity at release. Ball release velocities ranged from 14.5 to 25.8 m/sec, with peak elbow angular velocities averaging 1137°/sec. Peak elbow angular velocity typically was reached just prior (x = 28 msec) to release as the elbow approached full extension. Results are significant in establishing the efficacy of 3D techniques in evaluating throwing me chanics and may prove useful in: (1) identifying char acteristics of superior performers, (2) assessing differ ences in throwing technique between injured and non- injured populations, and (3) providing a kinematic data base for further studies of throwing kinetics and poten tial injury mechanisms.
Achillodynia and loss of heel pad shock absorbency
Authors: Jørgensen Uffe
Published: June 2007

The heel pad, with its specially organized elastic adi pose tissue, and the importance of heel pad shock absorption loss (soft heel pads) in the pathophysiology of achillodynia (particularly in heel strikers) is described and illustrated by case histories of three athletes. All had unusual, soft, flattened heel pads; all were heel- strikers ; and all were successfully treated with added external heel shock absorption. A diagnostic method to evaluate the shock absorbing ability of the heel pad is the "visual compressibility index" calculated on the basis of x-ray films of the heel, loaded and unloaded by body weight.
Shoulder strength following acromioclavicular injury
Authors: Walsh W. Michael , Peterson David A. , Shelton Guy , Neumann Randall D.
Published: June 2007

The acromioclavicular (AC) joint enjoys the dubious distinction of being one of the few joints in the body whose total dislocation is routinely treated by simply leaving the joint dislocated. Adherents of both conserv ative and operative treatment have presented reasons for their viewpoints. Residual shoulder weakness has been offered as a sequela of untreated acromioclavic ular injury and a reason for repairing the joint. An objective evaluation of shoulder strength would be valuable in determining the optimum treatment for this injury. The purpose of our study was to quantitate, using the Cybex II, the residual shoulder weakness following various modes of treatment. Seventeen pa tients with Grade III AC separations and eight patients with Grade II AC sprains were reviewed. Nine of the Grade III injuries were treated and eight nonoperatively. All Grade II injuries were treated nonsurgically. All pa tients were tested on the Cybex II isokinetic dynamom eter at both slow and fast speeds through various ranges of motion. Grade III injuries treated nonopera tively showed no significant strength deficits. Surgically treated Grade III injuries had a significant strength deficit in vertical abduction at fast speeds (19.8%) when compared to the uninjured shoulder. Interestingly, the Grade II injuries led to a significant weakness in hori zontal abduction (24.3%) at fast velocity.

Evaluation of subjective results showed that Grade III injuries treated conservatively had the most pain and stiffness, despite their strong shoulders. Patients with Grade III injuries treated operatively rated their overall outcome below that of those treated conservatively. We conclude that: (1) from the standpoint of objective strength, nonsurgical treatment of Grade III AC injury is as effective as surgical treatment; (2) the dilemma of Grade II AC injury continues, as shown by our findings of significant strength deficits; and (3) patient satisfac tion following treatment of AC injury does not mirror objective strength deficits.
Nerve injury and Grades II and III ankle sprains
Authors: Nitz Arthur J. , Dobner Joseph J. , Kersey Douglas
Published: June 2007

Nerve injuries associated with inversion sprains of the ankle have been mentioned in the literature on a case presentation basis only. Sixty-six consecutive patients with Grade II (30) and Grade III (36) ankle sprains were examined by electromyography 2 weeks after injury to determine the presence and distribution of nerve inju ries. Ankle active range of motion (AROM) and the number of weeks postinjury when the patient could heel/toe walk and return to full activity were also noted. Five patients (17%) with Grade II sprains had mild peroneal nerve injury and three (10%) injured the tibial nerve. Clinical measurements were normal by the end of the second week. Thirty-one patients (86%) with Grade III sprains injured their peroneal nerve, while 30 (83%) incurred posterior tibial nerve injury. Ankle AROM was impaired, and heel/toe walking (5.1 weeks) and return to full activity (5.3 weeks) were markedly pro longed. The likely cause of this injury is considered to be a mild nerve traction or a hematoma in the epineural sheath at the bifurcation of the sciatic nerve into pero neal and posterior tibial branches. This report indicates that a consistently high percentage of patients with Grade III ankle sprains sustain a significant injury to both motor nerves in the leg and that rehabilitation time is markedly prolonged.
Radiographic and histologic analyses of stress fracture in rabbit tibias
Authors: Guoping Li  , Shudong Zhang  , Gang Chen  , Hui Chen  , Anming Wang
Published: June 2007

Sequential changes in remodeling of the internal struc ture of the tibia caused by controlled, excessive jumping and running were studied in 20 rabbits. Vascular changes and circulatory disturbances within the cortical bone occurred before osteoclastic resorption. Degen eration and necrosis of osteocytes due to circulatory disturbances also occurred. Periosteal new bone for mation, found at and after 12 days of the experiment, was a compensatory reaction to support the tibia weak ened by accelerated osteoclastic resorption. Small cracks appeared at the cement line and developed through the neighboring cement line of the haversian systems. At 21 days, incomplete fracture of the tibial cortex was found in two rabbits. Complete fracture through one side of the cortex was seen in one animal at the 50th day of the experiment. In this study, how ever, most of the tibias did not have visible fracture lines after a period of stressful exercise. This result suggests that most tibias adapt to changes in stress requirements through proper internal remodeling so that a complete fracture does not occur.
Stability of the loaded ankle
Authors: Stormont Daniel M. , Morrey Bernard F. , An Kai-Nan , Cass Joseph R.
Published: June 2007

The stabilizing capacity of the ligaments and articular surface in the ankle was determined under defined physiologic loading conditions. The concept of primary and secondary constraints was adapted to the ankle. With physiologic loading, the articular surface ac counted for 30% and 100% of stability in rotation and version, respectively. That the articular surface was the sole source of inversion and eversion stability under the prescribed physiologic loading conditions has not been previously reported.

The demonstration that the articular surface resists inversion displacement in the loaded ankle supports the conclusion of previous studies that rotation, rather than inversion, may account for a type of clinically sympto matic ankle instability. Further, ankle instability may occur during loading and unloading but not once the ankle is fully loaded. The results of our study confirm the importance of the anterior talofibular and calcaneo fibular ligaments and suggest an important role for the deltoid ligament.
The emergency care network of a ski marathon
Authors: Gannon Daniel M. , Derse Arthur R. , Bronkema Pamela J. , Primley Donald M.
Published: June 2007

In this paper we report the system of emergency care that was used in a large-scale cross-country ski mara thon. We describe the typical terrain encountered, per sonnel required, physical facilities, communication sys tem, injury protocol, and types and numbers of injuries seen. We have found that many injuries can occur in a cross-country ski race, given specific race conditions.

A complete and efficient emergency care network is essential to the success of any athletic event similar to the one we report. These races are rapidly growing in number and size, yet we could not find any previous reports in the literature pertaining to the medical care necessary. We hope to provide a model for emergency care that can be applied to many different athletic events involving large numbers of participants and cov ering great distances.
Glenoid labrum tears related to the long head of the biceps
Authors: Andrews James R. , Carson William G. , Mcleod William D.
Published: June 2007

Tears of the glenoid labrum were observed in 73 base ball pitchers and other throwing athletes who under went arthroscopic examination of the dominant shoul der. Most of the tears were located over the anterosu perior portion of the glenoid labrum near the origin of the tendon of the long head of the biceps muscle into the glenoid.

At arthroscopy, the tendon of the long head of the biceps appeared to originate through and be continuous with the superior portion of the glenoid labrum. In many cases it appeared to have pulled the anterosuperior portion of the labrum off the glenoid. This observation was verified at arthroscopy by viewing the origin of the biceps tendon into the glenoid labrum as the muscle was electrically stimulated. With stimulation of the mus cle, the tendinous portion became quite taut, particu larly near its attachment to the glenoid labrum, and actually lifted the labrum off the glenoid.

Three-dimensional high-speed cinematography with computer analysis revealed that the moment acting about the elbow joint to extend the joint through an arc of about 50° was in excess of 600 inch-pounds. The extremely high velocity of elbow extension which is generated must be decelerated through the final 30° of elbow extension. Of the muscles of the arm that provide the large deceleration forces in the follow-through phase of throwing, only the biceps brachii traverses both the elbow joint and the shoulder joint. Additional forces are generated in the biceps tendon in its function as a "shunt" muscle to stabilize the glenohumeral joint during the throwing act.

On the basis of our observations that (1) the biceps tendon is subjected to large forces during throwing, (2) most tears of the glenoid labrum occur at the antero superior portion near the origin of the biceps tendon, and (3) the biceps tendon lifts the labrum off the glenoid when its muscle is stimulated, we believe that the tendon of the long head of the biceps may be a cause of tearing of the glenoid labrum in the throwing athlete.
Stress fracture of the ribs in female rowers
Authors: Holden David L. , Jackson Douglas W.
Published: June 2007

Stress fractures of the lower ribs related to sports are rare. Fractures of the ribs related to rowing sports have not been reported. We have documented seven cases of stress fractures of the lower ribs in female athletes; four were elite rowers and three were engaged in tennis, golf, and gymnastics. Each athlete was initially seen and treated elsewhere for muscular strain. All athletes presented with pain in the posterolateral thorax in and around the scapula. The time from onset of symptoms to diagnosis ranged from 2 to 6 months. Bone scans were used to document the fractures when roentgenograms were equivocal. Each athlete re sponded to a 4 to 8 week period of rest or training modification. Biomechanical analysis of the forces across the ribs demonstrates that these fractures tend to occur along the posterolateral segment where the bending stresses on the rib are greatest. The predom inant muscle forces are generated by the forced couple of scapular retraction and protraction acting through the serratus anterior. We postulate that inadequate strength and resistance training background in women is the cause for the apparent increased susceptibility of women to these skeletal injuries.
Paralysis of the serratus anterior in a world class marksman
Authors: Woodhead Alfred B.
Published: June 2007

The medical literature has produced a wide array of descriptive articles concerning paralysis of the serratus anterior; however, there has been no work on the role of sports in producing this condition. The functional anatomy, pathophysiology, and clinical evaluation are presented. A case study demonstrates the symptoms and progression of a typical patient with paralysis of the serratus anterior.
A biomechanical study of human lateral ankle ligaments and autogenous reconstructive grafts
Authors: Attarian David E. , Mccrackin Hugh J. , Devit Dennis P. , Mcelhaney James H. , Garrett William E.
Published: June 2007

The purpose of this study was to investigate the bio mechanical behavior of human anterior talofibular and calcaneofibular ligaments, as well as peroneus brevis, split peroneus brevis, and toe extensor tendon grafts. This article represents the first published data compar ing the most frequently injured ankle ligaments to the most commonly used autogenous reconstructive grafts.

Twenty fresh human ankles provided the bone-liga ment-bone and tendon graft specimens for biomechan ical testing on a Minneapolis Testing System. Protocol consisted of cyclic loading at physiologic deflections, followed by several load-deflection tests at varying velocities, followed by a final extremely rapid load to failure test.

The load-deflection data for all ligaments and tendons demonstrated nonlinearity and strain rate dependence. The maximum load to failure for the anterior talofibular ligament was the lowest of all specimens tested, while its strain to failure was the highest. The loads to failure of the peroneus brevis and split peroneus tendons were signficantly greater than the anterior talofibular ligament and approximately equal to the calcaneofibular liga ment. Strains to failure for all tendons were significantly less than ligament strains.

The high strain to failure of the anterior talofibular ligament demonstrates its physiologic function of allow ing increased ankle plantar flexion-internal rotation, while its low load to failure shows its propensity for injury. The greater strength of the tendon grafts ex plains the success of most reconstructive procedures in reestablishing stability in chronic ankle sprains; at the same time, the data presented suggest that those surgical procedures sacrificing the entire peroneus brevis tendon are unnecessary. Finally, the greater stiffness of the tendon grafts may cause postoperative decreases in ankle and subtalar motion.
Predictive leg strength values in immediately prepubescent and postpubescent athletes
Authors: Tabin Geoffrey C. , Gregg John R. , Bonci Tina
Published: June 2007

Sixty healthy, athletic children were treated on a Cybex II Dynamometer to obtain values for the relative strengths of the major muscle groups of the lower extremity. Prepubescent and postpubescent boys and girls were tested. Of the anthropometric parameters measured, lean body weight correlated best with max imal torque force development. In prepubescent chil dren, the mean maximal quadriceps torque force, meas ured in foot-pounds at 60 deg/sec, is equal to 70% of the lean body weight. In postpubescent subjects, the mean peak quadriceps torque equalled 80% of the lean body weight in girls and 90% of the lean body weight in boys. Correlations can be established between the maximal torque force generated by the quadriceps and the strength of the hamstrings, ankle dorsiflexors, and plantar flexors. The values obtained are useful in plan ning training and rehabilitation programs and in deter mining when an injured young athlete can safely return to his or her sport.
Instrumented measurement of anterior knee laxity in patients with acute anterior cruciate ligament disruption
Authors: Daniel Dale M. , Stone Mary Lou , Sachs Raymond , Malcom Lawrence
Published: June 2007

Instrumented anterior/posterior laxity measurements were performed on 138 patients evaluated within 2 weeks of injury with their first traumatic knee hemar throsis. All patients were tested with the MEDmetric Arthrometer model KT-1000 in a knee injury clinic. Seventy-five of the patients had knee arthroscopy. Thirty-three had arthrometer laxity tests under anes thesia. Eighty-seven percent of patients arthroscoped had anterior cruciate ligament (ACL) tears and 41 % had meniscus tears.

One hundred twenty normal subjects were tested to establish normal anterior laxity values. Three tests were used to evaluate anterior laxity: anterior displacement between a 15 and 20 pound force (compliance index), anterior displacement with a 20 pound force, and an terior displacement with a high manually applied force. Displacement measurements in normal subjects re vealed a wide range of normal laxity with a small right knee-left knee difference. For example, the 20 pound anterior displacement range was 3 to 13.5 mm with a right knee-left knee difference (mean ± SD, 0.8 ± 0.7 mm). Eighty-eight percent of the normals had a right- left difference of less than 2 mm.

In the 53 patients arthroscoped who had complete ACL tears, the anterior laxity measurements performed in the clinic were suggestive or diagnostic of pathologic anterior laxity in 50 patients.
Avulsion of the popliteus tendon
Authors: Naver Lars , Aalberg Jens Ranch
Published: June 2007

A case of isolated avulsion of the popliteus tendon in a 20-year-old male athlete is reported. The avulsion was caused by forward gliding of the femur on the fixed tibia which produced a chondral fracture and hemar throsis.
Skiers' thumb injuries associated with flared ski pole handles
Authors: Primiano George A.
Published: June 2007

Three skiers presented for treatment of significant thumb injuries sustained while skiing. Each patient was using a strapless ski pole handle with a flared thumb support. These skiers felt their interphalangeal (IP) joint flexion was blocked by the flare of their ski pole handle, causing their protruding thumb tip to be the point of initial impact, thus leading to their injury.

Prior to use of any ski pole handle, full flexion of the gloved thumb IP joint should be verified.
Replacement of the anterior cruciate ligament using a synthetic prosthesis
Authors: Arnoczky Steven P. , Warren Russell F. , Minei Joseph P.
Published: June 2007

The ACL of 21 adult mongrel dogs was replaced with a knitted dacron velour prosthesis. The biologic fate of these synthetic grafts was then evaluated at various intervals from 1 to 12 months postoperatively using routine histology and a vascular injection (Spalteholz) technique.

Following implantation the knitted dacron prosthesis was encapsulated with a vascular synovial tissue in a manner similar to that observed with autogenous pa tellar tendon grafts. This revascularization process was followed by a proliferation of fibroblasts throughout the extent of the prosthesis. While the grafts appeared to support a fibrous tissue proliferation in and around the design of the prosthesis, this tissue demonstrated only a random orientation of collagen fibers as late as 1 year postoperatively. It would appear, therefore, that al though the knitted dacron prosthesis is capable of inducing and supporting tissue encapsulation and in growth, it does not allow for the functional orientation of this tissue.
A preliminary study on the measurement of static and dynamic motion at the glenohumeral joint
Authors: Bonci Christine M. , Hensal Frederick J. , Torg Joseph S.
Published: June 2007

Measurement of glenohumeral joint motion has, for the most part, been performed with the simple goniometer. The purpose of this paper is to describe a method for measuring and recording static and dynamic external rotation of the glenohumeral joint using the Cybex II Isokinetic Dynamometer and an MFE model 815 X-Y plotter. Static range of motion was assessed at 60 deg/ sec using a slow arm action externally from a 90° abduction position. Dynamic motion was recorded at 300 deg/sec using a rapid rotational whipping action from a 90° abducted position.

Measurements were recorded on three groups of athletes, and the influences of sex, hand dominance, overarm activity, and surgery were analyzed. The sub jects in the first two groups were divided according to sex and their participation in overarm versus nonover arm (control) activities. Static and dynamic motion in both groups was significantly influenced by sex and hand dominance (P < 0.05). Although there was no overall difference in the motion measurements between the control and overarm groups, the interaction of this factor with sex and type of measurement was signifi cant. Males who participated in overarm activities had, on the average, more static range of motion than males in the control group.

A third group that had undergone a modified Bristow procedure for recurrent dislocation/subluxation of the shoulder demonstrated that static and dynamic range of motion were significantly reduced by the surgery (P < 0.05). The average differences in static and dynamic motion between the surgical arm and its nonsurgical counterpart were 17.5° and 21°, respectively, resulting in an overall range of motion difference of 19°.

The Cybex II Isokinetic Dynamometer and X-Y plotter provided a viable mechanical means of receiving and recording the full external rotation motion potentials of the limbs at varying speeds of movement. A combina tion of both static and dynamic measurement tech niques can provide a more quantitative assessment of the functional range available at the glenohumeral joint based on slow and high speed movement capabilities.
The epidemiology of aerobic dance injuries
Authors: Garrick James G. , Gillien Donna M. , Whiteside Patrice
Published: June 2007

Aerobic dance is currently the largest organized fitness activity primarily for women in the United States. In an attempt to identify and characterize the health problems associated with it, 351 students and 60 instructors from six facilities were followed for 16 weeks with weekly telephone calls. Of the 327 medical complaints reported during 29,924 hours of documented activity, only 84 (0.28 per hundred hours) resulted in any disa bility and only 2.1% required medical care. The shin/ leg, foot and ankle accounted for nearly two-thirds of the injuries. Instructors were twice as likely to be injured as students. Both a history of prior orthopaedic prob lems and a lack of involvement in other fitness activities resulted in higher injury rates. Injury rates were influ enced by the design and conduct of the aerobic pro gram but not by brand of shoe or type of flooring. Aerobic dance appears to offer students the potential for fitness enhancement with a minimal risk of injury.
The effect of wearing the complete Lenox Hill Derotation Brace on energy expenditure during horizontal treadmill running at 161 meters per minute
Authors: Zetterlund Allen E. , Serfass Robert C. , Hunter Robert E.
Published: June 2007

Ten volunteer subjects (x age = 26.6 ± 4.9 years, x height = 177.9 ± 5.6 cm, and x weight = 76.9 ± 11.2 kg) who had been wearing the Lenox Hill Derotation Brace (LHB) for a mean time of 23.9 ± 28.0 months were familiarized with horizontal treadmill running at 161 m/min with and without the LHB. They were then tested randomly for four runs, two with the LHB and two without the LHB. Metabolic measurements using a device that counted footstrikes on the treadmill were taken during the 3rd and 6th minutes of each run. Regardless of sampling time, wearing the LHB pro duced significantly higher values for VO2 (4.58%, P < 0.025) and heart rate (5.10%, P < 0.004) compared to the no brace condition. Regardless of whether or not the subjects were wearing the LHB, 6 minute values were significantly higher than 3 minute values for VO2 (5.89%, P < 0.0004), VE (10.08%, P < 0.004), heart rate (5.35%, P < 0.0000), and R (2.17%, P < 0.038). The mean 6 minute values of VO2 with (37.42 ± 3.55 ml/kg/min) and without (35.54 ± 2.17 ml/kg/min) the brace fall within the range of expected values of 28.1 to 39.3 ml/kg/min derived from regression equations from the literature which predict VO2 response to hori zontal treadmill running. Mean stride lengths while wearing the LHB (97.85 cm) were not significantly different from mean stride lengths without the LHB (98.56 cm). It is concluded that wearing the LHB pro duces a 4.58% increase in energy expenditure during horizontal treadmill running at 161 m/min which cannot be attributed to changes in stride length or to time of sampling during the run.
Chronic repetitive unrecognized flexion injury of the cervical spine (high jumper's neck)
Authors: Paley D. , Gillespie R.
Published: June 2007

Unrecognized flexion injuries of the cervical spine may lead to late instability and neurologic damage. These hidden flexion injuries may be from acute or chronic traumatic episodes. Cervical spine instability was seen in an amateur high jumper as a result of chronic repet itive flexion loading of her cervical spine due to incorrect landing technique. The instability from these types of flexion injuries is generally unrecognized on a routine lateral radiograph. The presence of slight anterior sub luxation, simple compression fractures, or subtle ky photic angulation at one cervical level should alert the physician to this diagnosis. Flexion extension views are useful to demonstrate this instability. Occupations and sports which involve repetitive flexion stress to the cervical spine are at risk for this type of late instability. Therefore, in high jumping careful attention to safe techniques of landing is of utmost importance.
The axillary nerve and its relationship to common sports medicine shoulder procedures
Authors: Bryan William Jay , Schauder Keith , Tullos Hugh S.
Published: June 2007

Cadaveric dissections have demonstrated the precar ious nature of the axillary nerve with relationship to three common sports medicine shoulder procedures: the anteroinferior acromioplasty and rotator cuff repair incision, the inferior capsular shift procedure, and the posterior portal for shoulder arthroscopy.
Acute patellar dislocations
Authors: Hawkins Richard J. , Bell Robert H. , Anisette Garth
Published: June 2007

Of 27 patients sustaining primary patellar dislocations, 20 were treated with immobilization and subsequent physiotherapy (including nine patients who underwent arthrosocoy) and seven with immediate surgical stabi lization and lateral release. The patients with predis posing factors such as patellofemoral malalignment, abnormal patellar configuration, and a history of prior symptoms of instability were more prone to recurrent dislocation and may benefit from operative intervention. Although the incidence of recurrence among those individuals can be decreased, at least 30% to 50% of all patients having sustained a primary patellar dislo cation will continue to have symptoms of instability and/ or anterior knee pain.
Anterior tibial compartment pressure during race walking
Authors: Sanzen Lennart , Forsberg Artur , Westlin Nils
Published: June 2007

In 14 race walkers the intramuscular pressure in the anterior tibial muscle was measured with a wick cath eter. At rest the pressure was 10 to 15 mmHg and increased by a factor of 10 during full speed walking. Those walkers who experienced pain in the anterior tibial muscle also had a higher than average pressure. Fasciotomy decreased the intramuscular pressure and relieved the pain.
Recurrent dislocation of the peroneal tendons
Authors: Martens Marc A. , Noyez Jan F. , Mulier Jozef C.
Published: June 2007

Nine patients (11 cases) with recurrent dislocation of the peroneal tendons who were treated by surgically rerouting the tendons under the calcaneofibular liga ment were reviewed. Mean follow-up time was 30.5 months. An excellent or good result was obtained in all cases. This operative technique was previously de scribed in 1975, by Sarmiento and Wolf, in a case report.
A performance test to monitor rehabilitation and evaluate anterior cruciate ligament injuries
Authors: Tegner Yelverton , Lysholm Jack , Lysholm Marketta , Gillquist Jan
Published: June 2007

A performance test simulating components of sports was devised to evaluate dysfunction after ACL injury. The test included a one-leg hop, running in a figure of eight (straight running and turn running measured sep arately), running up and down a spiral staircase, and running up and down a slope.

Twenty-six men with ACL injury, most of them soccer players, and 66 uninjured male soccer players were studied. Patients with ACL injury performed signifi cantly less well than the uninjured players. Test items of special interest were turn running in the figure of eight, stair running, and slope running, all of which place high demand on the knee.

It is concluded that a performance test of this design is useful for monitoring rehabilitation and for evaluating the patient's condition. Before sports can be resumed at the original level, normal strength and normal per formance should be regained.
Torque developed at simulated sliding between sport shoes and an artificial turf
Authors: Andreasson Gunnar , Lindenberger Ulf , Renström Per , Peterson Lars
Published: June 2007

Rotation torque is known to be one of many factors affecting the risk of injury in athletics. Experiments were performed to examine the torque and friction on differ ent sport shoes when sliding on an artificial turf. An apparatus was constructed in which it is possible to measure simultaneously the torque and the frictional force developed when a shoe slides on a surface. Measurements were made for 25 different shoes on an artificial turf. The frictional force was independent of the speed in the range 1 to 5 m/s. The torque was dependent on the physical distribution of the texture of the sole and slightly dependent on the frictional force. The results indicate that the physical distribution of the sole at the heel and toe, as well as the material, is of great importance for the torque developed.
Prophylactic knee bracing in college football
Authors: Hewson George F. , Mendini Ricky A. , Wang Jon B.
Published: June 2007

American football can be harmful to knees. In an at tempt to reduce the number and severity of knee injuries, the intercollegiate football team at the Univer sity of Arizona (Pacific Ten Conference) has been using protective braces since 1981. Objective evaluation of the effectiveness of this program is the purpose of this study. All linemen, offensive and defensive, as well as linebackers and tight ends were considered to be the players at greatest risk and were required to use the braces. The brace used was the Anderson Knee Sta bler.

Each player at each practice session or game was counted as one exposure. During the 4 years of brace use, there were 28,191 exposures, while the control group numbered 29,293 exposures. The data were analyzed from the perspectives of days lost from prac tice or games, player's position, the type and severity of injury, and the rate of injury per 100 players per season. Players at risk showed no trend to change in injury rate. Of the players at risk, the type and severity of injury in nonbraced and in braced groups were similar. A significant finding in players at risk was a two fold increase in knee ligament injury rate per 100 players when compared to rates for an entire team. The number of season-ending injuries remained unchanged. Prac tice time missed for third-degree medial ligament, and for medial meniscus injuries, was significantly lower in the braced group, but this was due to improved treat ment techniques initiated in 1981. Seven NCAA rule changes, directed at reducing knee injuries, have been introduced since 1981. Neither the rule changes nor the braces nor the combination thereof have had any apparent effect on the trend to knee injury in this study. We conclude that, in this study, knee injury prevention in a college football team was not improved by prophy lactic knee bracing.
Arthroscopic percutaneous lateral patellar retinacular release
Authors: Lankenner Peter A. , Micheli Lyle J. , Clancy Ruth , Gerbino Peter G.
Published: June 2007

Thirty-four arthroscopic lateral patellar retinacular re leases in 26 patients were evaluated retrospectively. Patients were carefully assessed for residual pain; they were also evaluated by various physical examination criteria. In addition, objective measurements of quadri ceps and hamstring strength were obtained with the Cybex II Isokinetic Dynamometer.

The surgical technique and postoperative manage ment are presented. Overall, there were 9% excellent results, 53% good results, 26% fair results, and 12% poor results. A total of 64.7% of the knees were im proved by the procedure.
Tibiofemoral joint forces during ergometer cycling
Authors: Ericson Mats O. , Nisell Ralph
Published: June 2007

Six healthy subjects pedaled on a weight-braked bicy cle ergometer at different workloads, pedaling rates, saddle heights, and pedal foot positions. The subjects were filmed with a cine-film camera and pedal reaction forces were recorded from a force transducer mounted on the left pedal. Net knee moments were calculated using a dynamic model, and the tibiofemoral shear and compressive force magnitudes were calculated using a biomechanical model of the knee. During cycling at 120 W, 60 rpm, midsaddle height, and anterior pedal foot position, the mean peak tibiofemoral compressive force was 812 N [1.2 times body weight (BW)]. The maximum anteriorly directed tibiofemoral shear force was found to be low (37 N). The compressive and shear forces were significantly increased by an increased ergometer workload. The pedaling rate had no influence on the tibiofemoral force magnitudes. The stress on the ACL was low and could be further decreased by use of the anterior foot position instead of the posterior.
Sports-related injuries in children
Authors: Tursz Anne , Crost Monique
Published: June 2007

In 1981 to 1982, within a 1 year period, details were recorded of children aged 0 to 15 years and 3 months, who were treated for accidental injury in a French health care district; 789 sports-related accidents were regis tered, representing 11 % of all accidents. Sports areas were the leading sites of accident among children over age 12. Out-of-school sports accidents were more fre quent among boys, but boys and girls had similar injury rates in school physical education. Compared to home, school, and road accidents, sports accidents had the highest rate of upper limb injury. The fracture rate was 22% and the hospitalization rate 11 %. In most cases children were injured without any participation of other players or sports equipment. Sports-related injuries were usually benign, but several hospital admissions for the same accident were required in 20% of the admitted children (significantly higher than in home, school, and road accidents), and the time elapsed be tween the accident and the end of the last stay in hospital was significantly greater than in other kinds of accidents. This might be explained by a higher rate of epiphyseal fractures (10%) and internal fixation (17%). Musculoskeletal sequelae were observed in 12% of inpatient children.