bluuebunny/crossref_metadata_2025 huggingface dataset:
Healing of experimental muscle strains and the effects of nonsteroidal antiinflammatory medication
Authors: Almekinders Louis C. , Gilbert Jerome A.
Published: June 2007

The healing process of muscle strains and the effect of nonsteroidal antiinflammatory medication were studied using an experimental animal model. A standardized strain of the tibialis anterior muscle in adult male rats was produced by a controlled stretch of the muscle. Groups I and II underwent a unilateral strain of the tibialis anterior muscle and were immobilized in the postinjury period. The rats in Group II were fed piroxi cam in the postinjury period. Group III underwent a sham procedure and were also immobilized. At 0, 2, 4, and 11 days postinjury both injured and contralateral control muscles were evaluated by determining tensile strength characteristics and histologic appearance.

Group I showed a significant drop in maximum failure load to 25.7% of the control leg at Day 2 with a gradual return to the level of Group III at Days 4 and 11 (40.9% and 50.1 %). Group II showed a similar drop but was still stronger than Group I at 2 days with 40.8% of the control leg and continued to drop until 4 days postinjury (33.7%). Histology showed a delay in inflammatory reaction and muscle regeneration in Group II. At 11 days both Groups I and II showed regenerated muscle fibers bridging the entire defect and an increase in endomyseal fibrosis. It is concluded that muscle strains continue to weaken in the early postinjury period. Non steroidal antiinflammatory medication, such as piroxi cam, might delay muscle regeneration.
Evaluation of warm-up for improvement in flexibility
Authors: Williford Henry N. , East Jennifer B. , Smith Furman H. , Burry Lou Ann
Published: June 2007

The purpose of this investigation was to evaluate the effects of warming the joints by jogging and then stretching on increases in joint flexibility. Subjects were 51 students enrolled in a physical conditioning class assigned to a jog and then stretch (JS), stretch and no jog (S), or a control group (C). Both the JS and S groups performed a series of stretching exercises 2 days a week for 9 weeks, with the JS group jogging for 5 minutes prior to stretching. Subjects were pretested and posttested for shoulder, hamstrings, trunk, and ankle flexibility with a Leighton flexometer. Results of t-tests indicated that significant increases in flexibility occurred for all of the joint angles evaluated for both the JS and S groups with the exception of trunk flexi bility for the JS group. An analysis of variance (ANOVA) of gain scores indicated a significant gain in ankle flexibility for the JS group compared to S and C groups. The S group produced a significant gain in trunk flexi bility compared to the JS group. Both JS and S groups were effective in improving flexibility, but when the gain scores were compared the results were variable. The data from this study again demonstrate that increases in flexibility can occur as a result of a static stretching training program. However, the results do not support the claim that warming the muscles prior to stretching by jogging will result in significant increases for all of the joint angles evaluated. Both methods offer possible advantages associated with improving joint flexibility.
Digital ischemia in baseball players
Authors: Sugawara Makoto , Ogino Toshihiko , Minami Akio , Ish Sechi
Published: June 2007

Eight baseball players developed digital ischemia as a result of repetitive ball impact. Symptoms and signs were coolness, numbness, cyanosis, paleness, and a positive reaction to the digital Allen's test. Seven of the eight players developed digital ischemia between the ages of 16 and 17. Angiograms of four patients with an occluded index digital artery are presented. Thermo- grams of four patients with a cool area of the left index finger are also presented.

We investigated the incidence of digital ischemia by administration of a questionnaire. The respondents were 578 players belonging to clubs in junior high schools, high schools, and colleges. No digital ischemia was found in 207 junior high school baseball players. The incidence increased in high school (66 of 299) and college (29 of 72). The probability of developing digital ischemia corresponded to the accumulated playing time. Digital ischemia occurred characteristically in the left index finger.
Analysis of the Müller anterolateral femorotibial ligament reconstruction using a computerized knee model
Authors: Gibson Michael , Mikosz Richard , Reider Bruce , Andriacchi Thomas
Published: June 2007

Iliotibial tract tenodesis has been described by Müller as part of the surgical treatment for anterolateral rota tory instability in the ACL deficient knee. The aim of this study was to use a previously described and vali dated computer model of the knee to calculate the effectiveness of Muller's extraarticular anterolateral fe morotibial ligament (ALFTL) graft as a substitute for the ACL or as an adjunct to an intraarticular ACL recon struction in the ACL deficient knee. This effectiveness was tested by simulating the application of a torque sufficient to create 15° of internal rotation or 5 mm of anterior displacement of the tibia on the femur at 0°, 15°, and 30° of knee flexion. The effects of moving the graft's proximal fixation point 1 cm superior, inferior, and anterior to the current surgical attachment site were examined to determine the amount of permissible surgical error in graft placement. The model predicts that the ALFTL is a useful restraint to internal rotation when it is performed with or without an intraarticular ACL reconstruction. The ALFTL graft took up greater amounts of tension and became more effective at in creasing angles of knee flexion. Placement of the ALFTL graft 1 cm anterior to the current surgical at tachment site decreases the vector component that lies perpendicular to the long axis of the tibia and conse quently reduces resistance to internal rotation. The ALFTL graft at any attachment site was ineffective in resisting pure anterior displacement between 0° and 30°.
Anterior glenoid labrum damage: A painful lesion in swimmers
Authors: McMaster William C.
Published: June 2007

The diagnosis of swimmer's shoulder has long con noted a malady usually perceived to be impingement syndrome. However, as greater understanding of shoulder mechanics and diagnosis has been applied to the shoulder of swimmers, it is apparent that they too suffer from a variety of problems common to all over head sports. This paper describes the functional insta bility problem of labral damage in the swimmer. Isolated labrum damage is part of a spectrum of anterior shoul der problems. This lesion is particularly disturbing to the swimmer, and its successful management through arthroscopic means is a boon. Correct diagnosis is paramount if a treatment is to be successful. The lesion in swimmers is described as well as its diagnosis by examination and computerized tomography (CT) ar thrography.
Injury patterns in nordic ski jumpers
Authors: Wright James R. , Hixson Edward G. , Rand Jay J.
Published: June 2007

No studies describing the types and frequencies of nordic ski jumping injuries have been reported in the medical literature. We examined records of injuries sustained at the Intervale Ski Jump Complex (15, 40, 70, and 90 meter jumps) in Lake Placid from 1980 to 1985. Forty-seven injured jumpers sustained 72 total injuries. The most frequent injuries were contusions. Fractures occurred in 11 jumpers; most were nondis placed. Upper extremity fractures outnumbered lower extremity fractures. Injuries requiring hospitalization were uncommon; none of these resulted in permanent disability. Injury rates for non-World Cup and for World Cup competitions were 4.3 and 1.2 injuries per 1,000 skier-days, respectively. This is roughly equivalent to injury rates in alpine skiing. Our study suggests that the dangers of nordic ski jumping have been overesti mated.
Acute ligamentous diastasis of the ankle without fracture
Authors: Marymont John V. , Lynch Mary A. , Henning Charles E.
Published: June 2007

Diastasis of the ankle syndesmosis without fracture is an uncommon injury. We present the results of bone scintigraphy as well as stress radiographs of the ankle performed on 27 athletes with suspected acute dias tasis of the ankle without fracture. Scintigraphy is a reliable procedure to guide initial management of those patients in whom stress radiographs of the ankle cannot be obtained because of pain or swelling, or in whom the radiographs were considered unreliable.

Scintigraphy correctly identified all 20 patients with positive stress tests (sensitivity = 100%). Two of seven patients with negative stress tests had positive scans (specificity = 71 %), for an accuracy of 93%.

We feel that scintigraphy is of value in a small subset of patients with suspected acute diastasis of the ankle syndesmosis on whom stress radiographs cannot be performed, or are considered inadequate in the imme diate postinjury period.
The relationship of vascularity and water content to tensile strength in a patellar tendon replacement of the anterior cruciate in dogs
Authors: McFarland Edward G. , Morrey Bernard F. , An Kai N. , Wood Michael B.
Published: June 2007

The methods and materials for ACL reconstruction are important issues for the practicing orthopaedic sur geon. In this study a model was developed to study the biological and biomechanical characteristics of a patel lar tendon autograft used for ACL reconstruction. Spe cifically it was hypothesized that since vascularity of these grafts reflects their "healthiness," strength and vascularity should be inversely related in the early pe riod after implantation. Using an over the top technique, a patellar tendon graft was placed in three groups of dogs and studied at 37, 57, and 120 days. Vascularity of the grafts was measured using technetium-tagged red blood cells, and percent water by weight was determined by dessication. Tensile testing to failure was performed using an MTS machine. The grafts became more vascular, more hydrated, less stiff, and less strong (by 4 weeks) than controls. By 16 weeks the vascular response was subsiding but the grafts remained only 40% as strong as controls. Percent water increased significantly over controls for all time periods. Decrease in strength correlated poorly with vascularity but correlated well with increase in percent water. These findings suggest that the change in strength of an intraarticular ACL replacement relates more to a basic rearrangement of its collagen-ground substance relationships, and that vascularity may re flect the inflammatory response bringing about these changes. The model developed in this study serves as a basis for further studies, and the findings reveal important information about the behavior of ACL graft ing materials.
The natural history of the anterior cruciate ligament autograft of patellar tendon origin
Authors: Amiel David , Kleiner Jeffrey B. , Akeson Wayne H.
Published: June 2007

A rabbit model for ACL reconstruction using autoge nous patellar tendon (PT) was used to study graft viability, its response to new physical forces, and the intrasynovial milieu. The autograft was assessed grossly, histologically, and biochemically with respect to time.

Histologic observations demonstrated that autografts were centrally acellular with a peripheral rim of cells at 2 weeks, and had a central focal proliferation of cells at 3 weeks and cellular homogeneity by 4 weeks pos toperation. Necrosis followed by cellular proliferation suggested that a population of cells other than the native PT fibroblasts may be inhabiting the graft.

Graft sequestration experiments demonstrated that autografts are repopulated by cells of extrinsic origin after transplantation. Autografts showed a gradual as sumption of the microscopic properties of normal ACL; by 30 weeks posttransplant the tissue characteristics were ligamentous in appearance. Histologic changes paralleled the biochemical metamorphosis: Type III col lagen was not observed in PT; however, a gradual increase in its concentration was seen in the grafts; by 30 weeks its concentration (10%) was the same as in normal ACL. Similarly, glycosaminoglycan content in creased from its normally low level in PT to that found in native ACL. Collagen-reducible cross-link analysis revealed that grafted tissue changed from the normal PT pattern of low dihydroxylysinonorleucine and high histidinohydroxymerodesmosine to the opposite pat tern seen in normal ACL by 30 weeks.

These data suggest that PT autografts undergo a process of "ligamentization" when placed in the ACL environment, and that cells responsible for this meta morphosis are of extragraft origin.
Treatment of ankle sprains in young athletes
Authors: Smith Ronald W. , Reischl Stephen F.
Published: June 2007

To study the incidence of fibulocollateral ligament ankle sprains in the young male athlete, a survey of 84 varsity basketball players was done. Seventy percent of the players had a history of an ankle sprain. Eighty percent of those with a positive history had multiple sprains. Most of the injuries were mild, but in 32% of the injuries, the athlete missed more than 2 weeks of play. No medical attention was sought in 55% of the cases. About 50% of the athletes with a sprain had residual symptoms from their injuries; 15% of the injured ath letes felt that their residual symptoms compromised their playing performance.

This article emphasizes the potential seriousness of the ankle sprain in the young athlete and presents a recommended method of management, including as sessment of severity, treatment, and rehabilitation.
Hook of the hamate fractures in athletes
Authors: Parker Richard D. , Berkowitz Mark S. , Brahms Malcolm A. , Bohl William R.
Published: June 2007

Five patients have been treated for six hook of the hamate fractures over the past 8 years by the authors. Of these, four patients were professional baseball play ers and one patient was an accountant. All fractures occurred while playing baseball; four while swinging a bat, and two secondary to a fall on an outstretched hand. Roentgenographic diagnosis was made by carpal tunnel view alone in two, oblique and carpal tunnel view in one, bone scan and subsequent carpal tunnel view in two, and computerized tomography in one fracture. Five of the fractures were through the base of the hook, while one was toward the tip. All patients ultimately underwent hook resection, four early and two late. The patient who sustained the tip of the hook fracture underwent resection of the fracture only to refracture the same hook at its base 6 months later. All patients returned to their previous level of activity in 6 to 8 weeks after surgery without loss of function. Hence, it is the authors' opinion that the entire hook should be resected to the base of the hamate as the primary form of treatment in hook of the hamate fractures.
Biomechanical and histological evaluation of muscle after controlled strain injury
Authors: Nikolaou Pantelis K. , Macdonald Beth L. , Glisson Richard R. , Seaber Anthony V. , Garrett William E.
Published: June 2007

This study correlates force generation and healing in muscle after controlled strain injury. Right tibialis ante rior (TA) muscles from 30 rabbits were strained to approximately 80% of failure while the left TA muscles served as control. Both injured and control muscles were then tested for ability to generate force. Seven animals were sacrificed immediately after testing and the muscles were examined grossly and histologically. Remaining animals were retested at 24 hours (N = 7), 48 hours (N = 8), and 7 days (N = 8). Contractile ability following injury was 70.5% of control immediately, 51.1% at 24 hours, 74.5% at 48 hours, and 92.5% at 7 days. Immediate histology showed limited distal fiber rupture and hemorrhage. By 24 hours, histology showed fiber necrosis, infiltration of inflammatory cells, edema, and hemorrhage. At 48 hours there was com plete fiber breakdown and intense inflammatory cell proliferation. At 7 days inflammation was reduced and collagen fibrosis more advanced. Our findings demon strate that injured muscle begins functional recovery by 48 hours despite inflammation and active healing. This suggests that decreasing muscle function seen clinically between 24 and 48 hours following strain injury may result from pain due to inflammation. Scarring and fibrosis seen at 7 days may explain the frequent recur rence of injury to strained muscles.
Observations on the treatment of lumbar disk disease in college football players
Authors: Day Arthur L. , Friedman William A. , Indelicato Peter A.
Published: June 2007

Over a 4 year period, 12 college players were treated for diskogenic injury. The most common position af fected was down-lineman. Symptoms consisted of low back and/or radicular pain. No players could recall the onset of symptoms relative to football activity; weight- lifting was associated with symptoms in three cases. Tentative clinical diagnosis was herniated disk disease. Method of diagnosis in the athletic population is pre sented along with results of surgical treatment. Percu taneous diskectomy appears to be successful for disk herniations occurring at the L4-5 space or higher.
High school football injuries: Evaluation
Authors: Thompson Nancy , Halpern Brian , Curl Walton W. , Andrews James R. , Hunter Stephen C. , McLeod William D.
Published: June 2007

An epidemiologic survey of the literature on high school football injuries revealed methodologic problems. These numerator-denominator inconsistencies and other con founding factors are discussed. The authors suggest a more reliable system of reporting these parameters to further reduce the risk of high school football injuries.
A review of tibial spine fractures in bicycle injury
Authors: Nichols John N. , Tehranzadeh Jamshid
Published: June 2007

Nine tibial spine fractures were studied. Three of these nine cases included younger patients who fell from a bicycle and sustained an isolated avulsion fracture of the tibial spine. In all three cases, the medial tibial spines of the right knees were fractured. The other remaining five medial tibial fractures included two motorcycle and two automobile accidents, together with one basketball injury. One of the nine tibial spine fractures involved the lateral tibial spine.
The synergistic action of the anterior cruciate ligament and thigh muscles in maintaining joint stability
Authors: Solomonow M. , Baratta R. , Zhou B.H. , Shoji H. , Bose W. , Beck C. , D'Ambrosia R.
Published: June 2007

The synergistic action of the ACL and the thigh muscles in maintaining joint stability was studied experimentally. The EMG from the quadriceps and hamstring muscle groups was recorded and analyzed in three separate experimental procedures in which the knee was stressed. The test revealed that direct stress of the ACL has a moderate inhibitory effect on the quadriceps, but simultaneously it directly excites the hamstrings. Similar responses were also obtained in patients with ACL damage during loaded knee extension with tibia subluxation, indicating that an alternative reflex arc unrelated to ACL receptors was available to maintain joint integrity.

The antagonist muscles (hamstrings) were clearly demonstrated to assume the role of joint stabilizers in the patient who has a deficient ACL. The importance of an appropriate muscle-conditioning rehabilitation program in such a patient is substantiated.
A biomechanical comparison of different surgical techniques of graft fixation in anterior cruciate ligament reconstruction
Authors: Kurosaka Masahiro , Yoshiya Shinichi , Andrish Jack T.
Published: June 2007

Different surgical methods of graft fixation in ACL re construction were examined to determine the effects on mechanical properties of the reconstructed ACL. Ten human cadavers were used in this study. Six different types of grafts were studied. The tendon grafts were removed from each cadaver and fixed to femurs and tibias as ACL substitutes with different surgical fixation methods, leaving femur-reconstructed graft- tibia preparations. The surgical techniques used were staple fixation, tying sutures over buttons, and screw fixation. In the latter, the screws were introduced through femoral and tibial drill holes from the outside in order to achieve interference fit as described by Lam bert. Tensile testing demonstrated that the original ACL is significantly stronger than the graft used for recon struction in linear load, stiffness, and maximum tensile strength. All of the failures of the reconstructed ACL grafts occurred at the fixation site, indicating that the mechanically weak link of the reconstructed graft is located at the fixation site. Among the different meth ods of fixation, one-third of the patellar tendon secured with a cancellous screw, especially with a custom de signed large diameter screw, showed significantly higher values. Although many other factors affect the success of ACL reconstruction, our study indicates that the method of surgical fixation is the major factor influencing the graft's mechanical properties in the im mediate postoperative period.
injury patterns in women's intramural flag football
Authors: Collins Robert K.
Published: June 2007

A prospective study of women's flag football injuries was carried out over a 4 year period at Mississippi State University. Data was gathered on 114 injuries. Organized intramural flag football activities caused 93% of the injuries observed (7% were injured in pick-up games). The finger accounted for 39%, knee for 16%, and ankle for 8% of these injuries. The type of injury was closely distributed among sprains, fractures, con tusions, and strains. Collisions, with other players and objects, resulted in 64% of these injuries. Offensive ball handlers (running backs and receivers) had the greatest probability of being injured. From this data, it is obvious that women's injury patterns are not the same as men's and that varsity injury data cannot be extrapolated to recreational injuries.
An electromyographic analysis of the elbow in pitching
Authors: Sisto Domenick J. , Jobe Frank W. , Moynes Diane Radovich , Antonelli Daniel J.
Published: June 2007

Elbow injuries are common in baseball pitchers. Curve balls are thought to increase this risk, particularly if the athlete begins throwing this pitch at an early age. The purpose of this paper is to identify forearm muscle firing patterns during the pitching cycle in an effort to under stand this etiology.

Dynamic EMG was performed on eight collegiate pitchers to evaluate extensor digitorum communis, brachioradialis, flexor carpi radialis, flexor digitorum superficialis, extensor carpi radialis longus, extensor carpi radialis brevis, pronator teres, and supinator. Each subject threw a fast ball and curve ball, which were filmed at 450 frames per second and synchronized with the EMG. These signals were converted from analog to digital records. Results showed low to moderate activity in all muscles during all phases of the pitch. The function is probably positioning to accept the transfer of energy from the larger trunk and girdle structures. The most notable difference between the fast ball and curve ball is a slight increase in the extensor carpi radialis longus and extensor carpi radialis brevis activity during late cocking, acceleration, and follow-through of the curve ball as compared to the fast ball. This differ ence, however, is not significant. In addition, there was no significant difference between the fast ball and the curve ball in the flexor-pronator group in any phase. We cannot substantiate that medial elbow problems are a result of an increase in the use of flexor muscles during the curve ball pitch.
Anterior cruciate reconstruction in the chronically unstable knee using an expanded polytetrafluoroethylene (PTFE) prosthetic ligament
Authors: Ahlfeld Steven K. , Larson Robert L. , Collins H. Royer
Published: June 2007

The purpose of this study is to review 30 patients with failed, multiply operated knees, or knees with gross instability which were reconstructed using the ex panded polytetrafluoroethylene (PTFE) prosthetic liga ment as a substitute for the ACL. The results were then compared with our experience with the proplast liga ment used in a previous clinical series.

This prospective review evaluated the patients pre operatively and at regular intervals during the postop erative period. The average followup was 24 months postoperation. Eighty-three percent of the patients had a satisfactory result, scoring greater than 140 points on a 200 point knee grading scale. Objectively, the anterior instability pattern was improved in 87% of the knees. Subjectively, pain of at least a mild degree persisted in 70% of the patients postoperatively. This pain seemed to correlate with articular cartilage changes documented intraoperatively. Major compli cations occurred in two patients.

In conclusion, the PTFE prosthetic ligament was an improvement over the proplast ligament in the recon struction of the multiply operated, unstable knee. The 83% satisfactory rate with the PTFE was promising compared to a 52% satisfactory rate using the proplast ligament. However, we encourage future long term studies of the PTFE prosthetic ligament in the recon struction of the ACL in the chronically unstable knee.
Lower extremity flexibility patterns in classical ballet dancers and their correlation to lateral hip and knee injuries
Authors: Reid D.C. , Burnham R.S. , Saboe L.A. , Kushner S.F.
Published: June 2007

Knee and hip problems account for up to 40% of injuries in classical ballet. Despite apparent flexibility, many dancers appeared to have tight iliotibial bands that contributed to lower limb problems. Thirty senior female ballet dancers were contrasted with thirty age-matched active volunteers for hip and knee range of motion, and the information derived was correlated with their ortho paedic medical histories. Dancers spent a reasonable period of time warming up, but it was usually with an unbalanced routine that emphasized hip abduction and external rotation to the exclusion of adduction work. This was reflected in the significantly lower range of passive hip adduction and internal rotation compared to the controls. Furthermore, the older and more ex perienced the dancer, the more this trend was exag gerated. This unbalanced flexibility may play a role in the production of lateral knee pain (30% of the dancers) and anterior hip pain (33% of the dancers). It is sug gested that more attention should be given to a bal anced stretching regimen as part of the dancers' war mup in an effort to reduce the frequency of some of the chronic hip and knee complaints.
The biomechanics of lateral knee bracing
Authors: Paulos Lonnie E. , France E. Paul , Rosenberg Thomas D. , Jayaraman Gopal , Abbott Paul J. , Jaen Jose
Published: June 2007

To better understand the role of preventive knee braces in injury prevention, a biomechanical study using fresh frozen cadaveric knees (N = 18) was conducted. Liga ment tensions and joint displacements were measured at static, nondestructive valgus forces as well as low- rate destructive forces. After quantifying and establish ing individual ligament contributions to valgus restrain ing function, knees were then braced with two different laterally applied preventive braces, the McDavid Knee Guard and the Omni Anderson Knee StabIer.The effects of lateral bracing were analyzed according to valgus force, joint line opening, and ligament tensions.

Valgus applied forces, with or without braces, consis tently produced medial collateral ligament (MCL) disrup tions at ligament tensions surprisingly higher than the anterior cruciate ligament (ACL) and higher than or equal to the posterior cruciate ligament (PCL). Although large joint displacements were necessary for complete ligament failure, bundle disruption in the MCL, ACL, and PCL was noted at much smaller joint openings. In Part I of this study, no significant protection could be documented with the two preventive braces used. Also, four potentially adverse effects were noted: MCL pre load, center axis shift, premature joint line contact, and brace slippage.
The percutaneous lateral retinacular release
Authors: Betz Randal R. , Magill John T. , Lonergan Robert P.
Published: June 2007

This study reviews 34 of 37 original patients who were reviewed in 1981 after previously undergoing percuta neous lateral retinacular release. Short-term satisfac tory results regarding reduction of pain and prevention of dislocation were maintained on this second followup (average, 48 months). With this increase in postopera tive time, patients with recurrent subluxation developed an increase in patellar slipping. Patients with chondro malacia and degenerative joint disease are less suited for long-term treatment. Long-term problems occurred in 1 of 34 patients (3%).
Strength training for prepubescent males: Is it safe?
Authors: Rians Clark B. , Weltman Arthur , Cahill Bernard R. , Janney Carol A. , Tippett Steven R. , Katch Frank I.
Published: June 2007

This study examined the safety of one type of strength training for prepubescent males. Eighteen males (av erage age, 8.3 ± 1.2 years) participated in a 45 min/ session, three session/week, 14 week supervised strength training program with an attendance rate of 91.5%. Concentric work was done almost exclusively. KinCom analysis showed significant strength gain in this group (P < 0.05), while an age, sex, and activity matched control group did not gain strength.

Safety was evaluated by injury surveillance, blood pressure and heart rate monitoring, scintigraphy, and creatine phosphokinase measurement. Effects on growth and development, flexibility, and motor perform ance were also investigated, as these are factors with an impact on sports injury occurrence.

Results showed that in the short term, supervised concentric strength training results in a low injury rate and does not adversely affect bone, muscle, or epi physes ; nor does it adversely affect growth, develop ment, flexibility, or motor performance. As the safety question is multifaceted, this should not lead to the conclusion that strength training for prepubescents is uniformly safe. Further research is needed.
Evaluation of patella viability after disruption of the arterial circulation
Authors: Scuderi Giles , Scharf Stephen C. , Meltzer Lon , Nisonson Barton , Scott W. Norman
Published: June 2007

Fifty patients whose surgical approach violated the arterial geniculate circulation to the patella were evalu ated to determine the subsequent effect on patella viability. Comparative postoperative radionuclide scans in 100 knees, 50 control and 50 surgical, revealed an avascular insult in only 7 knees (14%). It appears that the intratendinous circulation described by Björkström and Goldie1 protects the patella from an avascular insult in the presence of geniculate arterial disruption.
Soccer injuries in Saudi Arabia
Authors: Sadat-Ali M. , Sankaran-Kutty M.
Published: June 2007

Soccer injuries which were seen at the King Fahd University Hospital over a period of 12 months were analyzed. The majority of the patients were under 20 years of age. Two-thirds of the injuries involved soft tissue, while those to the bone and joint comprised one-third. The lower extremity was involved in 59%. Sixteen percent of the injuries were considered severe enough to require inpatient treatment.

We feel the high incidence of injuries can be reduced by better guidance and coaching at school and other training levels. At present, these patients are seen in the emergency room of our hospital and subsequently in the orthopaedic and fracture clinics. A specialized sports injury clinic staffed with medical and paramedical personnel with special interest in sports medicine would enable early and effective treatment returning athletes to play without undue delay.
Trabecular bone density and menstrual function in women runners
Authors: Cook Stephen D. , Harding Amanda F. , Thomas Kevin A. , Morgan Edward L. , Schnurpfeil Kimberly M. , Haddad Ray J.
Published: June 2007

Osteoporosis results in decreased bone mineral mass and reduced trabecular bone density. Although its etiol ogy remains unknown, studies have revealed differen tial changes in the bone mineral densities of postmeno pausal women, anorexic women, and amenorrheic fe male athletes. Correlations have also been made be tween estrogen deficiency and osteoporosis in both premenopausal and postmenopausal women. In order to examine the possibility of osteopenia, a group of 36 female runners between the ages of 15 and 44 years were evaluated for bone mineral density, menstrual function, and dietary habits. Serum calcium, phospho rus, and parathyroid hormone (PTH) levels were also determined for each participant, as were complete blood counts. Using dual photon absorptiometry, all participants underwent a 20 minute scan of the lumbar spine with specificity to the L1-14 vertebrae. The 36 subjects included 19 oligomenorrheic and 17 eumenor rheic women. Results of bone density analyses re vealed that the oligomenorrheic runners had signifi cantly lower calibrated bone mineral density (CBMD) than their eumenorrheic counterparts ( P << 0.01 ). Like wise, the PTH levels of the oligomenorrheic runners were also significantly lower ( P << 0.01). Analysis of dietary logs revealed no significant differences between the dietary habits, the calcium intake, or the caloric intake of the two groups. The data from this study indicate that there is a relationship between reduced serum PTH levels and the oligomenorrheic state. The loss of the protective effect of estrogen in the oligo menorrheic runners possibly contributed to their re duced bone mineral densities and could be a contrib uting factor in osteopenia.
Occult anterior subluxations of the shoulder in noncontact sports
Authors: Garth William P. , Allman Fred L. , Armstrong William S.
Published: June 2007

Athletes participating in noncontact sports involving abduction and external rotation of the shoulder (e.g., throwing) may develop occult recurrent subluxation manifested only as pain. The lack of contact trauma preceding symptoms, the failure of the athlete to ap preciate the instability, the relative rarity that the lesion has been previously recognized and reported, and the lack of objective evidence of instability often lead to incorrect diagnosis by the physician.

We report 30 shoulders in 28 patients with this lesion. Nineteen of these patients had been originally seen by other physicians prior to presenting to us and mis diagnosed. The newly described apical oblique roent genographic projection revealed Hill-Sach's lesions in 23 of 28 patients in this series. In addition, two of the five patients without Hill-Sach's lesions had bony changes pathognomonic for the Bankart lesion on the apical oblique projection. A total of 25 of the 28 patients had objective roentgenographic evidence of previous anterior subluxation. Eleven of the patients had arthros copic examinations confirming various pathology con sistent with anterior subluxation, including anterior or inferior labral tears, Hill-Sach's lesions, anterior inferior glenoid articular cartilaginous erosion, or Bankart le sions. Two of the twenty-eight patients had pathology in addition to evidence of previous occult subluxation which may have played a role in their symptoms, one having had osteolysis of the distal end of the clavicle and another having subacromical adhesions.
Peripheral tears of the meniscus
Authors: Baratz Mark E. , Rehak David C. , Fu Freddie H. , Rudert M.J.
Published: June 2007

The mechanical properties of the repaired meniscus may affect its ability to heal and to protect the articular surface against degenerative changes. We compared the immediate biomechanical consequences of open versus arthroscopic repair in the human cadaver knee. Additionally, having measured postoperative stresses at various degrees of knee flexion, we have addressed the effect of tethering of the meniscus, a question relevant to both meniscus repair and replacement. Peak stresses were measured by the Pressensor system. Fresh human cadaver knees were subjected to loading in an Instron unit, on an unconstrained base. Instanta neous loads were applied with the knee in 0°, 30°, or 60° of flexion, and stress distributions were measured after repair of a 2 cm peripheral tear, by an open or arthroscopic approach. The results of loading experi ments on five knees revealed no statistically significant differences between stresses after the two repairs. Similarly, there was no statistically significant difference between the normal and repaired menisci. In our model, this suggests that the immediate biomechanical con sequences of open and arthroscopic repair are equiv alent and that the "tethered" meniscus distributes loads as well as the normal meniscus.
Posterior cruciate ligament reconstruction by transfer of the medial gastrocnemius tendon
Authors: Roth James H. , Bray Robert C. , Best T.M. , Cunning L.A. , Jacobson R.P.
Published: June 2007

A retrospective study to determine the efficacy of me dial gastrocnemius tendon transfer for symptomatic PCL instability is presented. Results from a group of 31 patients undergoing this procedure were compared with a group of 8 patients managed conservatively while awaiting surgery.

The mean injury to follow-up interval was 82 months in the operated group and 104 months in the nonop erated group. The mean surgery to follow-up interval was 53 months. Sixty-nine percent of surgical patients were subjectively improved; however, 29 (91 %) contin ued to have pain and 19 (59%) continued to experience giving way. Thirteen patients from the operated group who had associated procedures performed were sig nificantly better subjectively than those with no asso ciated procedures (P < 0.05).

Physical examination demonstrated no difference in clinical laxity between the operated and nonoperated groups. Medial gastrocnemius transfer did not result in any significant reduction in anterior-posterior translation (KT-1000 assessment) when reconstructed knees were compared with control posterior cruciate deficient knees. Surgery, combined with subsequent immobili zation, may have also been responsible for the signifi cant reduction in lower limb function observed in the reconstructed patients.

We do not recommend this procedure as a primary PCL reconstruction.
The absent posterior drawer test in some acute posterior cruciate ligament tears of the knee
Authors: Hughston Jack C.
Published: June 2007

Over a 10 year period, 24 of 54 acute PCL tears in cases of straight medial instability demonstrated an absent or an equivocal posterior drawer test. Most of these (22, 91.6%) were contact injuries, and in the 11 cases where the mechanism of injury was known (45.8%), were incurred by a blow to the outer aspect of the leg while the foot was planted. The ACL was normal in 6 of the 24 knees. The abduction stress test at 0° extension was severely positive (2+ or more) in 21 of the 24 knees (87.5%).

The phenomenon of an absent or equivocal posterior drawer test in the situation of acute straight medial instability is felt to occur when the mechanism of injury does not stress, strain, or tear the arcuate complex. If the PCL tear is not discovered and repaired, repeated stressful activity stretches the arcuate complex, and the chronically unstable knee subsequently presents with a positive posterior drawer test.
Arthroscopic subacromial decompression
Authors: Gartsman Gary M. , Blair Major E. , Noble Philip C. , Bennett James B. , Tullos Hugh S.
Published: June 2007

Anterior acromioplasty as described by Neer has been an effective procedure for shoulder impingement syn drome. Recent presentations by Ellman suggest that an effective acromioplasty may be performed arthros copically. These clinical reports have not been sup ported by any laboratory experience. The purpose of our study was to examine the feasibility and attempt to quantitate the results of arthroscopic subacromial de compressions.

Six acromioplasties were performed according to the recommended technique of Dr. Neer to create a stand ard for comparison. Fourteen fresh postmortem speci mens were studied. In seven shoulders a standard acromioplasty was performed with an osteotome. In seven shoulders an acromioplasty was performed using standard arthroscopic approaches and motorized in struments. In five shoulders an isolated division of the coracoacromial ligament was performed arthroscopi cally. The coracoacromial ligament was completely di vided in all five cases. In the osteotome group adequate bone was resected in 75% (21/28) measured locations. In the arthroscopic group adequate bone was removed at 86% (24/28) location. This difference is not statisti cally significant.

In the cadaver, anterior acromioplasty was performed effectively and predictably with arthroscopic instru ments. This compared favorably to a conventional os teotome acromioplasty. It was concluded that coraco acromial ligament division can be accomplished.
Concentric versus eccentric isokinetic strengthening of the rotator cuff
Authors: Ellenbecker Todd S. , Davies George J. , Rowinski Mark J.
Published: June 2007

Twenty-two male and female college varsity tennis players trained for 6 weeks, one group using eccentric isokinetic internal and external shoulder rotation, and the second group using concentric isokinetic internal and external shoulder rotation. Subjects pretested and posttested both concentrically and eccentrically, so that training overflow and specificity could be examined. Three maximally hit tennis serves made before and after training, which were analyzed by high speed cin ematography to obtain ball velocity, served as a func tional performance measurement. Statistical analysis of peak torque (newton meters) and peak torque to body weight ratio have revealed significant concentric strength gains (P < 0.005) in the concentric as well as the eccentric training groups. Eccentric strength gains were demonstrated by the concentric training group at selected speeds (P < 0.05 and P < 0.005) but were not generated in the eccentric group at the P < 0.05 significance level. Functional test analysis shows an increase in maximal serve velocity at a significance level of P < 0.005 in the concentric training group, with no significant (P > 0.01) increases in the eccentric group.
Effect of viscoelastic shoe insoles on vertical impact forces in heel-toe running
Authors: Nigg B.M. , Herzog W. , Read L.J.
Published: June 2007

The purposes of this study were: 1) to compare the impact forces in running using running shoes with con ventional insoles to the impact forces using running shoes with four different viscoelastic insoles, 2) to discuss possible effects of the viscoelastic insoles on lower leg kinematics, and 3) to explain the force and kinematic results using a mechanical model. Kinetic and kinematic data were collected for 14 subjects running heel-toe at an average speed of 4 m/s. The results showed that the four tested viscoelastic insoles did not differ in variables describing the vertical impact forces (vertical force peak, time of occurrence of vertical force peak, maximum vertical loading rate) compared to the conventional insoles furnished in running shoes. Fur thermore, the viscoelastic insoles did not influence ki nematic variables of the lower extremities in a system atic way.
Evaluation of the results of extensor mechanism reconstruction
Authors: Cerullo G. , Puddu G. , Conteduca F. , Ferretti A. , Mariani P.P.
Published: June 2007

One hundred sixteen patients underwent extensor mechanism reconstruction. Ninety-four returned at fol lowup (3 to 11 years after surgery). Twenty-two pa tients were lost to followup. Subjectively, 74% of the patients had either an excellent or good result and 26% either a fair or poor result.

We found retrospectively, that the patients with either fair or poor results had a stable or only mildly unstable patella preoperatively.
Muscular coactivation
Authors: Baratta R. , Solomonow M. , Zhou B.H. , Letson D. , Chuinard R. , D'Ambrosia R.
Published: June 2007

The objective of this study was to quantify the coacti vation patterns of the knee flexor and extensor muscles as part of continued efforts to identify the role of the antagonist muscles in maintaining joint stability.

The simultaneous EMG from the flexor and extensor muscles of the knee were recorded during maximal effort, slow isokinetic contractions (15 deg/sec) on the plane parallel to the ground to eliminate the effect of gravity. The processed EMG from the antagonist mus cle was normalized with respect to its EMG as agonist at maximal effort for each joint angle. The plots of normalized antagonist EMG versus joint angle for each muscle group were shown to relate inversely to their moment arm variations over the joint range of motion. Additional calculations demonstrated that the antago nist exerts nearly constant opposing torque throughout joint range of motion. Comparison of data recorded from normal healthy subjects with that of high perform ance athletes with hypertrophied quadriceps demon strated strong inhibitory effects on the hamstrings coac tivations. Athletes who routinely exercise their ham strings, however, had a coactivation response similar to that of normal subjects.

We concluded that coactivation of the antagonist is necessary to aid the ligaments in maintaining joint stability, equalizing the articular surface pressure dis tribution, and regulating the joint's mechanical imped ance. The reduced coactivation pattern of the unexer cised antagonist to a hypertrophied muscle increases the risk of ligamentous damage, as well as demon strates the adaptive properties of the antagonist muscle in response to exercise. It was also concluded that reduced risk of knee injuries in high performance ath letes with muscular imbalance could result from com plementary resistive exercise of the antagonist muscle.
An in vivo analysis of the effect of transcutaneous electrical stimulation of the quadriceps and hamstrings on anterior cruciate ligament deformation
Authors: Kain Christopher C. , McCarthy John A. , Arms Steve , Pope Malcolm H. , Steadman J. Richard , Manske Paul R. , Shively Robert A.
Published: June 2007

Transcutaneous electrical muscle stimulation (TEMS) has been advocated as a method to rehabilitate the postoperative ACL repaired/reconstructed lower ex tremity. Isolated quadriceps contraction can potentially disrupt the ACL repair/reconstruction; to minimize this risk simultaneous quadriceps and hamstring stimulation has been used. This study measured the in vivo defor mation of the ACL during TEMS of the quadriceps and hamstrings.

Six legs in four Rhesus monkeys were immobilized in 0°, 45°, and 90° of flexion in neutral rotation using a Hoffman frame and pins placed through the proximal femur and distal tibia. The hamstrings and quadriceps muscles were stimulated with a dual channel electrical stimulator individually and simultaneously at each point of flexion, and ACL deformation was measured using a Hall effect device placed on the anterior medial fibers of the ACL. The following conclusions were made: 1) Isolated quadriceps contraction produces ACL elonga tion at 0° and 45° of knee flexion and produces ACL shortening at 90° of knee flexion. 2) Isolated hamstrings contraction produces ACL shortening at 45° and 90° of knee flexion and negligible effects at full knee exten sion. 3) It is not possible to simultaneously contract the quadriceps and hamstrings using separate stimulator pads for each muscle group. 4) At 45° of knee flexion when the quadriceps muscles are stimulated before the hamstring muscles and simultaneous contraction of both is then sustained, ACL lengthening occurs. 5) When the hamstring muscles are fired before the quad riceps muscles and simultaneous contraction of both is sustained, ACL shortening occurs.