bluuebunny/crossref_metadata_2025_split huggingface dataset:
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.
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.
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.
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.
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.
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.
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.
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.
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.
Concentric and eccentric torque comparisons for knee extension and flexion in young adult males and females using the Kinetic Communicator
Authors: Highgenboten Carl L. , Jackson Allen W. , Meske Neil B. 
Published: June 2007

The purposes of this investigation were to establish average leg torque values as a proportion of body weight for both concentric and eccentric contractions for leg extension and leg flexion, to determine leg flexion/extension ratios for both concentric and eccen tric contractions, and to compare those values in males and females from ages 15 to 34 years. The Kinetic Communicator (Kin-Com, Chattecx Corp., Chattanooga, TN), a relatively new computerized strength testing device, was used so that both concen tric and eccentric torques could be measured. Pilot study results indicated that Kin-Com results were reli able, r > 0.88. Average torque, across the full range of motion, and peak torque expressed in newton meters were divided by body weight in kilograms to produce torque values adjusted by body weight. No differences across age or sex were observed for floxion/extension ratios, but the males' weight-adjusted torque values were significantly (P < 0.01) greater than the females'. Younger (ages 15 to 24 years) male and female sub jects produced significantly (P < 0.01) greater torque for concentric contractions than older subjects (25 to 34 years). In rehabilitation programs using the Kin-Com, the weight-adjusted torque values and flexion/exten sion ratios will be useful in determining patients' strength recovery from knee or leg injury and/or sur gery.