bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanics of the healed meniscus in a canine model
Authors: Newman Alan P. , Anderson D. Ron , Daniels A.U. , Dales Mark C. 
Published: June 2007

The mechanical behavior of the intact canine stifle joint was studied, using a surgical model of meniscal injury and repair. Thirty-eight animals were divided into five study groups: Group S received only a sham arthro tomy (without a meniscal incision), Groups P13 and P26 received peripheral medial meniscal incisions, and Groups R13 and R26 received radial medial meniscus incisions. All meniscal incisions were repaired anatom ically with absorbable suture. Groups P13 and R13 were sacrificed at 13 weeks following surgery and Groups P26 and R26 at 26 weeks. Following sacrifice, the joints were subjected to gross and histologic ex amination, and structural and material properties test ing. All meniscal repairs healed, and the peripheral repairs were virtually invisible, with no articular damage. The radial repairs healed with 3 to 5 mm wide fibrovascular scars, and several joints demonstrated articular ero sions. The radial repair tissue contained unorganized collagen bundles and ground substance deficient in mucopolysaccharides. Groups S, P13 and P26 demonstrated no statistically significant differences between test and control limbs in compressive force-displacement behavior, input en ergy (EI), and ratio of dissipated to input energy (ED/EI). There were significant test-control differences in the load-displacement characteristics of Groups R13 (P < 0.05) and R26 (P < 0.05), with the repaired joint stiffer than the control. El decreased 26% in Group R13 (not significant) and 34% in Group R26 (P < 0.05), while the ratio ED/El increased from 27% to 44% in Group R13 (not significant) and from 31 % to 38% in Group R26 (P < 0.05). Medial compartment contact area did not change significantly in either peripheral repair group, but de creased by 25% in Group R13 (P < 0.05) and by 13% in Group R26 (P< 0.05). Yield stress, maximum stress, and Young's modulus decreased significantly (P < 0.05) relative to the controls in tensile tests of the radial repair tissue. There were no significant changes in these properties from 13 to 26 weeks. We concluded that in this animal model, the mechan ical function of the meniscus is restored following repair of peripheral longitudinal lesions ; however, it appears that in the radial repairs, progressive spreading at the repair site (filled by a fibrovascular scar) altered normal meniscal geometry and structure, adversely influencing mechanical function. Future studies may document whether protective measures (immobilization, limited weightbearing, etc.) can preserve normal mechanical function following repair of radial lesions.
Patellofemoral problems after anterior cruciate ligament reconstruction
Authors: Sachs Raymond A. , Daniel Dale M. , Stone Mary Lou , Garfein Richard F. 
Published: June 2007

Between 1982 and 1986, 126 patients who had under gone ACL reconstruction were followed in a prospec tive manner. One year follow-up statistics were re viewed for the presence of 13 different complications. The most prevalent complications were quadriceps weakness, flexion contracture, and patellofemoral pain. Quadriceps weakness (strength less than 80% of the normal side) was present in 65% of patients and cor related positively with flexion contracture, patellar irrit ability, and ACL reconstructions using patellar tendon grafts. Flexion contracture of 5° or more was present in 24% of patients and correlated positively with in creased age and patellar irritability. Patellofemoral pain was present in 19% of patients and correlated positively with flexion contracture. Clinical relevance: The three most common compli cations of knee ligament surgery are shown to be strongly interrelated. It is likely that a causal relationship is present in which flexion contracture causes patello femoral irritability, and that both of these factors, alone or in combination, result in quadriceps weakness. If this theory is correct, then it is crucial that postoperative rehabilitation programs place a major emphasis on the avoidance of flexion contracture.
The effect of enforced exercise on the healing of ligament injuries
Authors: Burroughs Paul , Dahners Laurence E. 
Published: June 2007

Previous studies have documented that mobilization ad libitum has a beneficial effect on the healing of ligaments as compared to immobilization. This study was under taken to determine whether enforced exercise (over and above motion ad libitum) would have a further beneficial effect or, instead, an adverse effect on the healing of ligaments. Large male Sprague-Dawley rats with unrepaired transections of the medial collateral ligament were sep arated into five groups of similar mean weights. Two of these groups had the anterior cruciate ligament and the medial capsule transected in addition to the medial collateral ligament, rendering the knee unstable. The groups were then subjected to varying regimens of enforced exercise (swimming). After 12 days, the me chanical characteristics of the femur, medial collateral ligament, and tibia complex were evaluated. Rats with intact secondary valgus stabilizers (medial capsule and anterior cruciate ligament) that swam daily for either 5 (moderate) or 15 (near exhaustion) minutes were found to have increases in the tensile strength of the femur, medial collateral ligament, tibia complex as compared to rats that did not swim. Unstable knees (with tran sected secondary valgus stabilizers) did not show an increase in the tensile strength of the femur, medial collateral ligament, tibia complex when subjected to moderate increase in enforced exercise (swimming 5 minutes). The unstable groups were, however, signifi cantly more lax than the groups that underwent identi cal exercise regimens but had intact secondary valgus stabilizers. Significant differences in the stiffness of the ligaments in the different groups were not detected. In conclusion, exercise had a beneficial effect on the strength of the medial collateral ligament in stable rat knees but an adverse effect on the laxity of the MCL when the knees had been rendered unstable.
Medial approach in elbow arthroscopy
Authors: Lindenfeld Thomas N. 
Published: June 2007

The author undertook a cadaveric dissection study to confirm the hypothesis that starting with the anterior medial portal in elbow arthroscopy is safer than starting with the anterior radial portal. In six cadaveric elbows, the capsule was distended with saline. Both anterior medial and anterior radial approaches were made with the elbow flexed to 90°. Four and one-half millimeter arthroscopic sheaths were inserted and obturators were then left in place while the saline was drained; expanding polyurethane foam was used to distend the capsule. We allowed the polyurethane foam to harden and then dissected all elbows, with special attention given to exposure of the radial and medial nerve and the brachial artery. The hardened foam allowed for continued capsular distension during these dissections and recreated nor mal distances from instrument portals to neurovascular bundles. The minimum distance from the path of the arthroscopic sheath to the large neurovascular struc tures was then measured. The distance from the medial portal to the nearest neurovascular structure (median nerve, brachial artery) averaged 23 mm. The distance from the radial portal to the nearest neurovascular structure (radial nerve) averaged 3 mm. The ulnar nerve averaged a 25 mm clearance from the medial portal. Even when the medial portal was made by an incorrect method, the minimum clearance to the median nerve averaged 11 mm. The most frequently recommended current standard technique for elbow arthroscopy involves beginning with an anterior radial portal. However, the findings in this study suggest that an anterior medial portal is a superior starting point. The medial portal allows good visualization of the joint and helps with safe and accu rate placement of the radial portal. Most importantly, the medial portal may be placed a safe distance from important neurovascular bundles.
Shoulder arthroscopy: its role in evaluating shoulder disorders in the athlete
Authors: Hurley John A. , Anderson Thomas E. 
Published: June 2007

We retrospectively reviewed 100 initial shoulder ar throscopies from a general sports medicine orthopaedic practice to determine if arthroscopy is helpful diagnos tically and to see if specific lesions correlate well with specific diagnoses. Seventy-two percent of the patients in the review had glenoid labral tears. Ninety-two per cent of patients who had a diagnosis of either recurrent anterior dislocation or recurrent anterior subluxation demonstrated a tear of the anterior inferior margin of the glenoid labrum. Sixty-eight percent of patients with a diagnosis of impingement demonstrated tears at the superior margin of the labrum. There was a significant difference between throwing and nonthrowing athletes. Partial rotator cuff tears were noted in 18 patients, the majority occurring in throwing athletes. Other abnor malities, such as degenerative joint changes and biceps tendon lesions, were also noted at the time of arthros copy. A large number of glenoid labral tears found at the time of arthroscopy appeared to be associated with conditions other than instability, which may or may not affect the throwing athlete. There also appeared to be a high correlation between tears in the anterior inferior glenoid labrum and anterior instability. Arthroscopy en abled us to identify other significant information about the status of the biceps tendon or the undersurface of the rotator cuff. These are areas in which problems might otherwise have been missed. Degenerative changes of the articular surface, not apparent on plain radiographs, may also be better evaluated arthroscop ically.
Physician care for interscholastic athletes in Michigan
Authors: Lindaman Lynn M. 
Published: June 2007

Between January 1989 and March 1989 the athletic directors of the 711 high schools in the Michigan High School Athletic Association were surveyed as to what sports and levels of competition each school offered and what level of medical care was available. Fifty- seven percent of the surveyed schools returned prop erly completed forms. Sixty-one percent of the schools responding reported having a physician available for at least one team at some time during the year. This was almost universally the football team; with 59% of the schools with varsity football reporting a physician pres ent at either a practice or a contest at least once during the year. Only 13% of the schools reported having a physician available for a team other than varsity football. Seventy-four percent of all varsity teams had neither a physician nor an athletic trainer present at any time during the year. Comparison of the results of this study with similar studies performed in Michigan in 1975 and 1979, as well as studies in other states, demonstrates that de spite the increased awareness and popularity of sports medicine, there has been no appreciable change in the amount of access interscholastic athletes have to phy sician care.
Force displacement characteristics of the posterior cruciate ligament
Authors: Bach Bernard R. , Daluga Daniel J. , Mikosz Richard , Andriacchi Thomas P. , Seidl Robert 
Published: June 2007

The percent force changes in the posterior cruciate ligament were calculated using a previously validated computerized knee model after the femoral insertion sites were varied 2.5 and 5.0 mm in an anterior, pos terior distal, anterior distal, and posterior distal direc tion. The tibial insertion sites were also varied 2.5 and 5.0 mm in the medial, lateral, proximal, and distal direc tions. Percent force changes were measured over a range of 0° to 90°. These insertion sites simulated potential surgical placement errors. Results of this study demonstrated that the greatest percent force changes in the posterior cruciate ligament were at full extension. The greatest absolute percent force change between 0° and 90° of flexion was with a femoral insertion of the posterior cruciate ligament placed 5 mm anterior to its normal attachment site, which resulted in a 39% change in the posterior cruciate ligament force. Distal femoral site attachment had the least effect (10% at 5.0 mm). Alterations at the tibial attachment site were less sensitive than on the femur; the greatest absolute percent force changes occurred with medial and lateral attachment sites (14% and 15%, respectively, at 5.0 mm). A minimal amount of percent force changes were seen between 45° and 75° of knee flexion in all positions tested for both tibial and femoral attachment sites. This model suggests that, like the anterior cruciate ligament, the force in the posterior cruciate ligament is also sensitive to attachment site position. As in anterior cruciate ligament studies, the femoral attachment site was found to be more sensitive. The greatest percent force changes for the posterior cruciate ligament were seen at the extremes of the knee motion tested (i.e., 0° and 90°). The posterior cruciate ligament sensitivity to graft placement lends credence to the importance of anatomic reconstruction. Results of this study can also be extrapolated to help in designing early continuous passive motion and rehabilitation programs, with the safest range of knee motion between 45° and 75°.
Instrumented evaluation of knee laxity: A comparison of five arthrometers
Authors: Anderson Allen F. , Snyder Robert B. , Federspiel Charles F. , Lipscomb A. Brant 
Published: June 2007

We performed a prospective study on 50 subjects with normal knees and 50 patients with chronic unilateral disruption of the anterior cruciate ligament. In a random ized testing sequence, both groups were examined with five arthrometers: the MEDmetric KT-1000, the Stryker Knee Laxity Tester, the Acufex Knee Signature System, the Dyonics Dynamic Cruciate Tester, and the Genucom Knee Analysis System. Each examination was performed according to protocol with the knee at 30° of flexion. The total anterior laxity measurements of the normal subjects using the Dyonics Dynamic Cruciate Tester and Acufex Knee Signature System were approxi mately half of the KT-1000, Stryker, and Genucom values. A comparison of the side-to-side measurements revealed no statistically significant difference in the values of the five arthrometers. However, the Genucom showed an unacceptably high number of normal sub jects with laxity values that suggested an anterior cru ciate ligament tear. Total anterior laxity measurements of the anterior cruciate ligament deficient knees were almost twice those of normal knees with each device except the Genucom. Comparison of the mean side-to-side differ ence in the patients with ACL deficiency demonstrated statistically significant differences in the values re corded with the five arthrometers. The side-to-side difference was greatest with the KT-1000 and least for the KSS. In the 89 N Lachman test, the KT-1000 and Stryker demonstrated the highest diagnostic accuracy. The maximumm manual test improved the accuracy of each device.
Arthroscopic meniscectomy in patients over the age of 40
Authors: Bonamo John J. , Kessler Kevin J. , Noah Joseph 
Published: June 2007

One hundred eighteen patients, aged 40 or older, underwent partial meniscectomy and limited debride ment of coexisting grade III or grade IV degenerative articular cartilage lesions. No curettage, abrasion ar throplasty, or subchondral drilling was performed. The average age of the patients was 57 years (range, 40 to 78). The mean followup was 3.3 years (range, 1 to 7). Sixty-three similar patients who also underwent partial meniscectomy but did not have the finding of significant coexisting articular surface erosion were studied for comparison. Of the 118 patients in the group with articular lesions (78 men and 40 women), 71 (60%) rated their improve ment as significant, 22 (19%) as moderate, and 15 (13%) as mild; 10 (8%) noted no improvement. Although 98 (83%) were generally satisfied with their result, only 57 (48%) reported satisfaction for sports. However, 89 (75%) had resumed and continued recreational athletic activities. Results tended to be worse in women, in patients older than 60, in those with moderate or severe tibiofemoral radiographic changes, those who had a grade IV articular lesion, and those with longer follow up time. Although results were poorer in patients with coex isting grade III or grade IV degenerative arthritis, ar throscopic partial meniscectomy and limited debride ment was an acceptably effective procedure in patients over the age of 40.
The repair of osteochondral defects using an exogenous fibrin clot
Authors: Paletta George A. , Arnoczky Steven P. , Warren Russell F. 
Published: June 2007

To evaluate the ability of an exogenous fibrin clot to hasten or optimize the repair of full-thickness articular cartilage defects, 4-mm diameter, full-thickness articu lar cartilage defects in 20 adult mongrel dogs were packed with an exogenous fibrin clot that had been prepared from each animal. The defects were created in a loaded and unloaded portion of the femoral troch lea. The healing response was then examined using routine histology at various intervals from 2 weeks to 6 months. Both the experimental (clot-filled) and control (empty) defects healed through a proliferation of fibrous con nective tissue that eventually modulated into fibrocar tilage. However, in the 2-, 4-, and 8-week animals, the experimental defects (both loaded and unloaded) dem onstrated a more organized and advanced healing re sponse than did the control defects. This difference was less pronounced in the 12- and 24-week animals. In all specimens, the clot-filled defects healed more uniformly than controls with less surface depression. In general, the unloaded sites were more uniform in heal ing than the corresponding loaded sites.
Magnetic resonance imaging of the posterior cruciate ligament
Authors: Gross Michael L. , Grover Jaswinder S. , Bassett Lawrence W. , Seeger Leanne L. , Finerman Gerald A.M. 
Published: June 2007

This study was undertaken to determine the accuracy of magnetic resonance image scanning in detecting posterior cruciate ligament injury, and to determine those clinical situations where it can add the most useful information. A retrospective study was conducted on 201 patients who underwent surgery after magnetic resonance scanning of their knees. Two additional pa tients who did not have surgery but had clinical findings grossly positive for posterior cruciate ligament injury were included in the analysis of magnetic resonance imaging accuracy. In all, there were 190 intact and 13 torn posterior cruciate ligaments. In a review of the clinical findings in the 11 patients with surgically docu mented tears, we found that all 11 had positive mag netic resonance scans. In 4 of the 11, magnetic reso nance imaging provided especially useful information regarding the status of the ligament. For the 190 normal ligaments, there were no false-positive scans; for the 13 torn ligaments, there were no false-negative scans. Therefore, specificity and sensitivity estimates for this group were both 100%. Magnetic resonance imaging proved to be an accu rate modality for evaluating the integrity of the posterior cruciate ligament. If used in the proper setting, it can provide useful information for diagnosing posterior cru ciate ligament injuries.
Arthroscopic and histologic analysis of human patellar tendon autografts used for anterior cruciate ligament reconstruction
Authors: Rougraff Bruce , Shelbourne K. Donald , Gerth P. Kevin , Warner Jeffrey 
Published: June 2007

To evaluate the fate of patellar tendon autografts in humans, the knees of 23 patients who had undergone anterior cruciate ligament reconstruction were exam ined 3 weeks to 6.5 years postoperatively. Arthroscopy and biopsy were performed on all patients. The patellar tendon autografts progressed through four stages of ligamentization after reconstruction. The first stage of repopulation occurred during the first 2 months and was evidenced by a viable 3-week speci men with an increasing fibroblast number and active nuclear morphology. Over the next 10 months, the graft went through a stage of rapid remodeling in which the fibroblast count increased markedly, the active nuclear morphology and neovascularity remained increased, and more areas of degeneration were present as the percentage of mature collagen decreased. The third stage or "maturation" stage occurred over the next 2 years and was characterized by a slow decline in the nuclei and the maturation of the collagen matrix. By 3 years the grafts were ligamentous by all histologic criteria examined. The authors conclude that human autogenous patel lar tendon grafts are viable as early as 3 weeks post operatively and may not go through a necrotic stage. They then progress through a prolonged process of ligamentization that takes as long as 3 years to com plete.
Relationship between changes in length and force in in vitro reconstructed anterior cruciate ligament
Authors: Muneta Takeshi , Yamamoto Haruyasu , Sakai Hiroshi , Ishibashi Toshiro , Furuya Kohtaro 
Published: June 2007

The effect of tibial and femoral attachment site on the length change and force of an anterior cruciate ligament graft during unloaded flexion in eight cadaver speci mens was examined. Two tibial sites (anteromedial and central portion of the anterior cruciate ligament attach ment) and three femoral sites (anterior and central portions of the anterior cruciate ligament attachment, and over-the-top) were evaluated. Graft length changes between all combinations of attachment sites were measured from full extension to 150° of passive flexion at 15° intervals using the displacement of a 2-mm inextensible cord. The anterior cruciate ligament was then reconstructed using a Kennedy Ligament Aug mentation Device, and graft forces at the same angles of passive flexion were measured with a buckle trans ducer. Graft length change and force were more affected by the femoral attachment site than the tibial site. There was a close correlation between length change and force measurements in flexion, but not near extension. The pattern of force and length change versus flexion angle for a given combination of attachment sites some times varied over the knees tested. Our results suggest that intraoperative isometry measurements are worth while for indicating an overloaded graft in flexion; how ever, length changes near extension may not ade quately reflect graft force, creating the possibility that a graft may be more highly loaded than realized.