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PubMed2001

Leeds-Keio artificial ligament: a new concept for the anterior cruciate ligament reconstruction of the knee.

The features of the Leeds-Keio artificial ligament, which was developed as a collaborative project between the University of Leeds in the UK and Keio University, are introduced. The ligament is made of polyester, and has a mesh structure. The diameter of the polyester fibers is 22 microns. The ligament has a tensile strength sufficient for anterior cruciate ligament (ACL) reconstruction, and fatigue tests have shown satisfactory durability of the ligament. The stiffness of the Leeds-Keio artificial ligament is about 200 N/mm, which is similar to the natural ACL. A combination of a bone plug and stapling is used for the bone fixation, taking into consideration the strength in both the initial mechanical fixation and the long term fixation. From an animal study, it was shown that fibrous tissue was induced around the artificial ligament, and the collagen fibers became aligned in the longitudinal direction of the ligament. For the clinical experience, one-hundred and thirty five cases were reviewed. The Lachaman sign disappeared in 87.4%, and the pivot shift sign disappeared in 88.1%. Side-to-side difference of anterior displacement of the knee, measured with a KT-2000 knee arthrometer at 30 degrees of flexion, was less than 3 mm in 85.9%. More than 90% of the patients experienced full range of motion. Thus, from the clinical results, it can be concluded that reasonable stability was obtained with the operation. If the Leeds-Keio artificial ligament may not be the perfect substitute for the ACL, both experimental and clinical studies indicate that it represents a major forward step in the history of knee ligament surgery.

Animals↗
PubMed2000

Anterior cruciate ligament reconstruction with the Leeds-Keio artificial ligament.

The Leeds-Keio (L-K) artificial ligament, developed for knee ligament reconstruction, is made of polyester with a maximum tensile strength of 2200 N. This implant works not only as a ligament but also as a scaffold onto which natural tissue grows from synovium. In an animal experiment, each strand of the L-K ligament was covered with new tissue by 2-3 weeks after anterior cruciate ligament reconstruction. Eight weeks postoperatively, abundant fibrous tissue with extensive vascularity covered the implant, which was still histologically immature. After 16 weeks, vascularization and tissue induction began to subside, and histologic analysis showed dense fibers running longitudinally and parallel. By 36 weeks, the new ligament looked like a natural anterior cruciate ligament, although histologically more cells could be seen than in the natural ligament. This maturation was observed only when the substitute was implanted under good tension. Clinically, the surgical procedure has been improved over the past 10 years, to the current practice in which the tape-in-tube double L-K ligament employs a small piece of autogenous tissue to promote early tissue induction and maturation. Using this practice (n = 135), more than 85% of the patients were satisfied subjectively, objectively, and arthroscopically at the 5-year postoperative FU period. Few patients had joint effusion postoperatively. Sacrifice of autogenous tissue is minimal. The patient can return to activities of daily living within 2 weeks, and more than 50% of them to sports within 10 weeks, and the new ligament is expected to keep its function for a long period as ingrowth completes the structure biologically.

Activities of Daily Living↗
PubMed1991

The effect of section of the medial collateral ligament on force generated in the anterior cruciate ligament.

Ten fresh-frozen knees from cadavera were instrumented with a specially designed transducer that measures the force that the anterior cruciate ligament exerts on its tibial attachment. Specimens were subjected to tibial torque, anterior tibial force, and varus-valgus bending moment at selected angles of flexion of the knee ranging from 0 to 45 degrees. Section of the medial collateral ligament did not change the force generated in the anterior cruciate ligament by applied varus moment. When valgus moment was applied to the knee, force increased dramatically after section of the medial collateral ligament; the increases were greatest at 45 degrees of flexion. Section of the medial collateral ligament had variable effects on the force generated in the anterior cruciate ligament during internal rotation but dramatically increased that generated during external rotation; these increases were greatest at 45 degrees. Section of the medial collateral ligament increased mean total torsional laxity by 13 degrees (at 0 degrees of flexion) to 20 degrees (at 45 degrees of flexion). Application of an anteriorly directed force to the tibia of an intact knee increased the force generated in the anterior cruciate ligament; this increase was maximum near the mid-part of the range of tibial rotation and minimum with external rotation of the tibia. Section of the medial collateral ligament did not change the force generated in the anterior cruciate ligament by straight anterior tibial pull near the mid-part of the range of tibial rotation.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed2002

Arthroscopically assisted combined anterior and posterior cruciate ligament reconstruction in the multiple ligament injured knee: 2- to 10-year follow-up.

PURPOSE: This study presents the 2- to 10-year results of 35 arthroscopically assisted combined anterior cruciate ligament and posterior cruciate ligament (ACL/PCL) reconstructions evaluated preoperative and postoperatively using Lysholm, Tegner, and Hospital for Special Surgery knee ligament rating scales, KT-1000 arthrometer testing, stress radiography, and physical examination. TYPE OF STUDY: Case series. METHODS: This study population included 26 men and 9 women with 19 acute and 16 chronic knee injuries. Ligament injuries included 19 ACL/PCL/posterolateral instabilities, 9 ACL/PCL/medial cruciate ligament (MCL) instabilities, 6 ACL/PCL/posterolateral/MCL instabilities, and 1 ACL/PCL instability. All knees had grade III preoperative ACL/PCL laxity and were assessed preoperatively and postoperatively with arthrometer testing, 3 different knee ligament rating scales, stress radiography, and physical examination. Arthroscopically assisted combined ACL/PCL reconstructions were performed using the single-incision endoscopic ACL technique and the single femoral tunnel-single bundle transtibial tunnel PCL technique. PCLs were reconstructed with allograft Achilles tendon (in 26 cases), autograft bone-patellar tendon-bone (BPTB) (in 7 cases), and autograft semitendinosus/gracilis (in 2 cases). ACLs were reconstructed with autograft BPTB (16 cases), allograft BPTB (12 cases), Achilles tendon allograft (6 cases), and autograft semitendinosus/gracilis (1 case). MCL injuries were treated with bracing or open reconstruction. Posterolateral instability was treated with biceps femoris tendon transfer, with or without primary repair, and posterolateral capsular shift procedures as indicated. RESULTS: Postoperative physical examination revealed normal posterior drawer/tibial step-off in 16 of 35 (46%) knees. Normal Lackman and pivot-shift test results were found in 33 of 35 (94%) knees. Posterolateral stability was restored to normal in 6 of 25 (24%) knees, and tighter than normal knee results were found in 19 of 25 (76%) knees evaluated with the external rotation thigh foot angle test. In this group, 30 degrees varus stress testing was normal in 22 of 25 (88%) knees, and grade 1 laxity was found in 3 of 25 (12%) knees. 30 degrees valgus stress testing was normal in 7 of 7 (100%) surgically treated MCL tears, and in 7 of 8 (87.5%) brace-treated knees. Postoperative KT-1000 arthrometer testing mean side-to-side difference measurements were 2.7 mm (PCL screen), 2.6 mm (corrected posterior), and 1.0 mm (corrected anterior) measurements, a statistically significant improvement from preoperative status (P =.001). Postoperative stress radiographic side-to-side difference measurements measured at 90 degrees of knee flexion and 32 lb posteriorly directed proximal force were 0 to 3 mm in 11 of 21 (52.3%) knees, 4 to 5 mm in 5 of 21 (23.8%), and 6 to 10 mm in 4 of 21 (19%) knees. Postoperative Lysholm, Tegner, and HSS knee ligament rating scale mean values were 91.2, 5.3, and 86.8, respectively, showing a statistically significant improvement from preoperative status (P =.001). CONCLUSIONS: Combined ACL/PCL instabilities can be successfully treated with arthroscopic reconstruction and the appropriate collateral ligament surgery. Statistically significant improvement is noted from the preoperative condition at 2- to 10-year follow-up using objective parameters of knee ligament rating scales, arthrometer testing, stress radiography, and physical examination. Postoperatively, these knees are not normal, but they are functionally stable. Continuing technical improvements will probably improve future results.

Accidental Falls↗
PubMed1999

[13-MHc high frequency ultrasound of the lateral ligaments of the ankle joint and the anterior tibia-fibular ligament. Comparison and results of MRI in 64 patients].

PURPOSE: Determination of the value of 13-MHz high-frequency ultrasound in the diagnosis of acute injuries of the lateral ankle ligaments and the anterior tibiofibular ligament by comparison with MRI. METHOD: Sonography was performed prospectively in 64 acutely injured patients using a mechanical 13-MHz sector probe; for diagnosis of the anterior tibiofibular ligament a 15-MHz sector probe was employed during the course of this trial. Using a 0.2-T unit for MRI examination, T1-weighted (TR 580 ms, TE 24 ms) and T2-weighted (TR 3000 ms, TE 80 ms) spin-echo sequences were obtained in various oblique axial imaging planes. RESULTS: In the differentiation of intact and injured ligaments, ultrasound and MRI agreed in 95.3% of cases for the anterior fibulotalar ligament, in 88.3% for the fibulocalcanear ligament and in 85.0% for the anterior tibiofibular ligament. CONCLUSION: Lesions of the anterior talofibular and fibulocalcanear ligament can be accurately demonstrated by ultrasound if a 13-MHz sector scanner is used. The detection of lesions in the anterior tibiofibular ligament is more difficult. With increasing experience and by using a 15-MHz sector scanner, better results can be expected for this ligament.

Ankle Injuries↗
PubMed2002

Healing of subfailure ligament injury: comparison between immature and mature ligaments in a rat model.

This study evaluated biomechanical properties of healing ligament following subfailure (grade II) injury by comparing young and mature animals in a rat lateral collateral ligament (LCL) model. One randomly selected LCL was stretched in situ using a custom designed device in eighteen young (21 days) and eighteen skeletally mature (8 months) male rats. Animals were euthanized at 0, 7, and 14 days post-surgery, and ligament ultimate stress, strain at failure and laxity were determined (n = 6 pairs per group). At time 0 after introduction of stretch injury, ligament laxity was present in both groups. The mature rats had 54 +/- 9% strength of the control while the immature rats had 58 +/- 11% of the strength of the control, representing a consistent and significant injury. The immature and mature ligaments showed similar patterns of cellular damage post-injury and had similar modes of mechanical failure. Ligament laxity decreased in each group as healing time increased, however ligament laxity did not completely recover in either group after 2 weeks of healing. After 7 and 14 days of healing, the mature rats, respectively, had only 63 +/- 14%% and 80 +/- 8% strengths of the controls while the immature rats had 94 +/- 6% and 94 +/- 10%. Hence, mechanical data showed that immature animals recovered their strength after a grade II sprain at a faster rate than mature animals. However, ligament laxity was still present in both groups two weeks after the injury and was not completely removed by growth in the immature group. These findings are clinically relevant since joint laxity after injury is common, and these results may explain the presence of continued instability in a joint injured at a young age. Hence, this study, with a new injury model, showed differences in ligament healing associated with maturity and quantified the clinically observed persistance of ligament laxity.

Age Factors↗
PubMed2001

Fibrocartilage at the entheses of the suprascapular (superior transverse scapular) ligament of man--a ligament spanning two regions of a single bone.

The suprascapular ligament converts the suprascapular notch into a foramen separating the vessels and nerve of the same name. It connects 2 regions of the same bone and does not cross any joint, and no mechanical function has yet been attributed to it. Nevertheless, variations in its thickness and length, and its tendency to ossify, suggest that the ligament responds to changes in mechanical load. This should be reflected in the composition of the extracellular matrix. The primary purpose of the present study is to demonstrate that the suprascapular ligament has fibrocartilaginous entheses (i.e. insertion sites), even though there is no obvious change in insertional angle that directly results from joint movement. Such a change is more typical of tendons or ligaments that cross highly mobile joints. The complete ligament (including both entheses) was removed from 7 cadavers shortly after death and fixed in 90% methanol. Cryosections were immunolabelled with a panel of monoclonal antibodies against collagens (types I, II, III, VI), glycosaminoglycans (chondroitin 4 sulphate, chondroitin 6 sulphate, dermatan sulphate and keratan sulphates), proteoglycans (aggrecan and versican) and link protein. Both entheses were strongly fibrocartilaginous, and a moderately fibrocartilaginous matrix was also detected throughout the remainder of the ligament. The extracellular matrix of both entheses labelled strongly for type II collagen, aggrecan and link protein. The fibrocartilaginous character of the entheses suggests that the insertion sites of the ligament are subject to both compressive and tensile loading and are regions of stress concentration. This in turn probably reflects the complex shape of the scapula and the presence of a conspicuous indentation (the suprascapular notch) near the ligament. The loading patterns may reflect either the attachment of muscles and/or the forces transmitted to the suprascapular ligament from the neighbouring coracoclavicular ligament.

Adult↗
PubMed1993

A method for measuring tension in small ligaments: an application to the ligaments of the wrist carpus.

A new technique has been devised for measuring the in situ tension in small ligaments. It is based on measuring the tension in an axially loaded flexible cable with pinned endpoints by deflecting the cable laterally and measuring its lateral load and deformation. Studies were performed in which nylon line and bone ligament bone preparations were placed in a materials tester and loaded in axial tension. Axial load as measured by lateral load and deformation was found to agree with the known load to within 8 percent. The method was sensitive to error in determination of ligament length, nonperpendicularity of the laterally applied load to the long axis of the ligament, and when used in situ, impingement of the ligament on a third bone causing bending. A device, consisting of an LVDT mounted to a rigid frame with its core rod connected to a load cell, was developed. The position of the core rod was controlled by a manual screw drive, and a hook on the other end of the core rod was used to deflect the ligament laterally. This device was applied to the study of tensions in five ligaments of the palmar wrist carpus, in seven cadaver specimens. Results showed that the radioscaphocapitate (RSC) and radiolunate (RL) ligaments had significantly greater tensions than the lunotriquetral (LT), the triquetrocapitate (TC), and scaphocapitate (SC) ligaments. For the four positions of the hand tested, neutral, 14 deg radial and 14 deg ulnar deviation, and 28 deg of extension, ligament tensions were found to be unaffected by position.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed2001

Retain or sacrifice the posterior cruciate ligament in total knee arthroplasty? A histopathological study of the cruciate ligament in osteoarthritic and rheumatoid disease.

BACKGROUND: The decision whether to retain or resect the posterior cruciate ligament in total knee arthroplasty is at present determined clinically by preoperative radiological variables focusing upon the amount of joint destruction, and subsequent soft tissue contractures. However, these variables give only indirect information on the histological integrity and proprioceptive properties of the posterior cruciate ligament. METHODS: Twenty posterior cruciate ligaments, obtained during total knee arthroplasty, were evaluated histologically to study the relation between the degree of preoperative radiological joint destruction, structural integrity of the posterior cruciate ligament and the neurological integrity of the targeted tissue. Eleven patients had osteoarthritis and nine patients rheumatoid arthritis. Haematoxylin and eosin, Alcian blue (mucoid degeneration), elastica von Gieson, Gomori (elastic fibres and collagen), and immunohistochemical staining for neural structures were used. RESULTS: In all but one of the posterior cruciate ligaments, morphologically intact neural tissue was present in the peritendineum of the ligaments. Structural integrity of the collagen framework was present in only seven posterior cruciate ligaments. These cases all had grade three or four radiological joint destruction. In 13 of the specimens a certain degree of mucoid degeneration of collagen was present. All patients with grade five radiological knee joint destruction displayed mucoid degeneration and irregularity of the posterior cruciate ligament fibres. CONCLUSION: Because of the extensive architectural and probably functional damage of the posterior cruciate ligament in patients who have grade five radiological knee joint destruction, retention of the posterior cruciate ligament in knee prosthesis should not be advocated.

Adult↗
PubMed2000

Total knee arthroplasty ligament balancing and gap kinematics with posterior cruciate ligament retention and sacrifice.

This cadaver study was undertaken to gain insight into the effects that posterior cruciate ligament retention and sacrifice would have on the amount of deformity correction obtained with medial and lateral structure release during total knee arthroplasty. Twenty-seven cadaveric specimens were used to sequentially release medial and lateral structures with and without posterior cruciate support. Each release sequence was tested in full extension and 90 degrees flexion. In full extension, the resulting change into valgus after release of the posterior cruciate ligament, posteromedial capsule/oblique ligament complex, superficial medial collateral ligament, and pes anserinus and semimembranosus tendons was 6.9 degrees, and it increased to 13.4 degrees in 90 degrees flexion. With preservation of the posterior cruciate ligament this decreased to 5.2 degrees in extension and 8.7 degrees in flexion. Changes seen in 90 degrees flexion were significantly greater than those in full extension. For the valgus knee model with release of the posterior cruciate ligament, posterolateral capsule, lateral collateral ligament, iliotibial band, popliteus tendon, and lateral head of the gastrocnemius, 8.9 degrees of change into varus was seen in extension and 18.1 degrees in 90 degrees flexion. With posterior cruciate ligament retention 5.4 degrees and 4.9 degrees of change into varus was seen in extension and flexion, respectively. Significantly less change with retention of the posterior cruciate ligament was seen with both medial and lateral release and more opening of the flexion gap was seen on the release side of the joint for all groups except those with lateral release with sacrifice of the posterior cruciate ligament.

Aged↗
PubMed1991

[Study on reconstruction of the anterior cruciate ligament in the monkey knee using polyester artificial ligament].

We performed an experimental study of ACL reconstruction utilizing polyester artificial ligament(Leeds-Keio). The quality of regenerated ligaments was compared between two different procedures; in the one 1 cm wide Leeds-Keio ligament was used alone for reconstruction(Group 1) and in the other, Leeds-Keio ligament of the same size was augmented with one-third width of free patellar tendon (Group 2). Eighteen knees of nine Japanese monkeys were used. The specimens were obtained at 2, 6 and 12 months after the operation and investigated macroscopically, microscopically and biomechanically. Regenerated ligaments in Groups 1 and 2 appeared identical and grossly normal. However, more mature and stable ligament was noted in the cylinder of artificial ligaments after 2 months after operation in Group 2 than in Group 1 in terms of both quality and quantity. Biomechanically, however, the maximum the tension in the regenerated ligaments was approximately 1/2-1/3 of that of normal ACL. The authors believe that more mature ligament was made in ACL reconstruction when the artificial ligament was augmented with autogenous soft tissue.

Animals↗
PubMedDate not supplied

Acute grade III medial collateral ligament injury of the knee associated with anterior cruciate ligament tear. The usefulness of magnetic resonance imaging in determining a treatment regimen.

BACKGROUND: The appropriate management of acute grade III medial collateral ligament injury when it is combined with a torn anterior cruciate ligament has not been determined. HYPOTHESIS: Magnetic resonance imaging grading of grade III medial collateral ligament injury in patients who also have anterior cruciate ligament injury correlates with the outcome of their nonoperative treatment. STUDY DESIGN: Prospective cohort study. METHODS: Seventeen patients were first treated nonoperatively with bracing. Eleven patients with restored valgus stability received anterior cruciate ligament reconstruction only, and six with residual valgus laxity also received medial collateral ligament surgery. RESULTS: Magnetic resonance imaging depicted complete disruption of the superficial layer of the medial collateral ligament in all 17 patients and disruption of the deep layer in 14. Restoration of valgus stability was significantly correlated with the location of superficial fiber damage. Damage was evident over the whole length of the superficial layer in five patients, and all five patients had residual valgus laxity despite bracing. Both groups had good-to-excellent results 5 years later. CONCLUSIONS: Location of injury in the superficial layer may be useful in predicting the outcome of nonoperative treatment for acute grade III medial collateral ligament lesions combined with anterior cruciate ligament injury.

Acute Disease↗
PubMed2000

Operative treatment of combined anterior and posterior cruciate ligament injuries in complex knee trauma: can the cruciate ligaments be preserved?

A retrospective study was performed focusing on operative treatment after combined anterior cruciate ligament (ACL)/posterior cruciate ligament (PCL) injuries. The operative treatment included the preservation of one or both cruciate ligaments. Twenty-eight patients, average age 30 years (range: 12-55 years), were evaluated 5.4 years (range: 1-14 years) postoperatively. Twenty-two operations were performed in patients with acute injuries (<30 days after trauma) and 6 operations in patients with chronic instabilities (>30 days after trauma). Both cruciate ligaments were preserved by suture or refixation in 16 patients. Suture of one and reconstruction of the other cruciate ligament with autologous tendon graft was performed in 12 cases. In addition, 61 procedures (meniscal suture/resection, medial/lateral reconstruction, tendon suture, and open reduction and internal fixation were performed. Postoperative treatment included continuous passive motion and protected weight bearing. Eleven (27% acute, 83% chronic) patients required revision (ACL/PCL reconstruction, osteotomy, and meniscal repair). At follow-up, 43% of the patients were very satisfied and 46% were satisfied. Seventy-one percent (89% preinjury) of the patients were able to maintain intensive and moderate International Knee Documentation Committee (IKDC) activity levels. The IKDC evaluation of the patients (acute %/chronic cases %) was graded for symptoms: A 39% (45/17), B 35% (27/67), C 15% (18/0), and D 11% (9/17); for range of motion: A 42% (36/67), B 42% (50/17), C 16% (14/17), and D 0%; and for ligaments: A 21% (18/17), B 33% (45/0), C 42% (32/83), and D 4% (5/0). Radiographic findings were A 18%, B 41%, and C 41%. Primary repair of acute injuries was superior to the delayed repair of chronic instabilities. Preservation of cruciate ligaments in acute combined ACL/PCL tears results in a satisfying knee function despite distinct residual ligament instability. Although suture of the cruciate ligaments in open technique is a therapeutic option in acute multiligamentous knee injuries, it is not recommended for the treatment of chronic instabilities.

Adult↗
PubMed1991

Tensions in the anterior and posterior cruciate ligaments of the knee during passive loading: predicting ligament loads from in situ measurements.

Cruciate ligament tensions were predicted for anteroposterior (AP) tibial translation at 20 degrees, 30 degrees, 80 degrees, and 90 degrees of knee flexion based on in vitro measurements from six cadaver knees. A three-dimensional trigonometric equation was derived to calculate cruciate ligament tension as functions of AP force applied to the tibia and knee flexion angle (KFA). AP forces less than or equal to 150 N were applied. Ligament tension increased with applied AP force. The relationship between ligament tension and applied AP force appeared linear, but a Hotteling's T2 test failed to demonstrate a linear relationship. Tensions in the anterior cruciate ligament (ACL) attained magnitudes of approximately equal to 140 N. Tensions in the posterior cruciate ligament (PCL) attained magnitudes of approximately equal to 220 N. An analysis was performed to determine the sensitivity of ligament tension to hypothetical errors in the experimentally measured parameters used to compute ligament tension. The new method we report can be used to determine tensions in the ligaments of the knee or other joints for various loading conditions.

Adult↗
PubMed2001

Mucoid degeneration of the anterior cruciate ligament mistaken for ligamentous tears.

OBJECTIVE: To describe the MR features of mucoid degeneration of the anterior cruciate ligament (ACL) in a series of patients with MRI findings that were mistaken for tears in the majority of cases but who were found to have an intact ligament at arthroscopy. We will suggest a pathologic entity corresponding to this finding and describe some characteristic features that can be used to identify this entity on MRI. DESIGN: A retrospective analysis of 10 MRI examinations of the knee was performed after arthroscopic evaluation. Prearthroscopic MRI findings had been interpreted as a tear in six patients prospectively and in the remaining four the diagnosis of mucoid degeneration was suggested and ultimately proven. All patients had an intact ACL by preoperative clinical examination, examination under anesthesia, and at arthroscopy. RESULTS: MRI examinations demonstrated an ill-defined ACL, greater in girth than the normal ligament and characterized by increased signal on all sequences. The high-signal ligament was oriented in the normal direction of the ACL. The overall appearance of the ligament was retrospectively described as like a celery stalk. Arthroscopy demonstrated mechanically intact ligaments with a normal to expanded external appearance. Probing of three of the ligaments caused a material to be expressed and pathologic evaluation resulted in the diagnosis of cystic, mucoid degeneration. CONCLUSION: Mucoid degeneration and an intact ACL can be suspected when an apparently thickened and ill-defined ligament with increased signal intensity on all sequences is identified in a patient with a clinically intact ligament.

Adult↗
PubMed1996

Biomechanical consequences of replacement of the anterior cruciate ligament with a patellar ligament allograft. Part I: insertion of the graft and anterior-posterior testing.

Nineteen fresh-frozen knee specimens from cadavera were tested for anterior-posterior laxity with 200 newtons of force applied to the tibia. A cylindrical cap of subchondral bone containing the tibial insertion of the anterior cruciate ligament was isolated with a coring cutter and was potted in acrylic. A thin wire was connected to the undersurface of the cap, and relative displacement between the cap and the tibia was measured with an isometer as the knee was extended. The cap of bone was connected to a load-cell that recorded force in the intact ligament during anterior-posterior testing with the tibia locked in neutral, internal rotation, and external rotation. The anterior cruciate ligament was then resected, and a femoral tunnel was drilled at the site where the isometer readings from the wire were the same as those obtained for the intact anterior cruciate ligament. A bone-patellar ligament-bone graft was used to reconstruct the anterior cruciate ligament, and the isometer measurements were repeated with the graft in place. The graft was pre-tensioned at 30 degrees of flexion to restore normal anterior-posterior laxity. Anterior-posterior laxity tests were repeated at this level of pre-tension (laxity-matched pre-tension) as well as at a level that was forty-five newtons greater (over-tension). The moment required to extend the knee was measured before and after insertion of the graft at both levels of pre-tension. When the tibia was locked in positions of internal and external rotation, the anterior-posterior laxities and the forces in the anterior cruciate ligament (generated by an anterior force applied to the tibia) were significantly less than the corresponding values with the tibia in neutral rotation at 20, 30, and 45 degrees of flexion (p < or = 0.05). Isometer readings for the intact anterior cruciate ligament indicated that the cap of bone retracted into the joint a mean and standard deviation of 3.1 +/- 0.8 millimeters as the knee was extended from 30 degrees of flexion to full extension. For each specimen, the isometer measurements for the trial wire and for the graft were within 1.5 millimeters of those for the intact anterior cruciate ligament. At laxity-matched pre-tension (mean, 28.2 +/- 16.8 newtons), the mean anterior-posterior laxities of the reconstructed knees were within 1.0 millimeter of the corresponding means for the intact knees between 0 and 45 degrees of flexion. Over-tensioning of the graft by forty-five newtons decreased the anterior-posterior laxity a mean of 1.2 millimeters at 30 degrees of flexion. Over-tensioning of the graft did not change the moment required to bring the knee to full extension.

Aged↗
PubMed1992

The effect of a ligament-augmentation device on allograft reconstructions for chronic ruptures of the anterior cruciate ligament.

A prospective study was performed to determine the effect of a combination of a ligament-augmentation device with a bone-patellar ligament-bone allograft for the treatment of chronic rupture of the anterior cruciate ligament. One hundred and fifteen knees in 110 patients were divided into two groups. Group BLB consisted of sixty-six knees in sixty-four patients who were managed with a bone-patellar ligament-bone allograft only, and Group BLB-LAD consisted of forty-nine knees in forty-six patients who were managed with both the allograft and a ligament-augmentation device. Preoperatively, there were no statistically significant differences between the two groups with regard to fifteen variables. All patients were managed with the same postoperative program of immediate motion and rehabilitation of the knee. All patients returned for evaluation at a mean of thirty-four months (range, twenty-three to fifty-three months) postoperatively. The results were evaluated with a comprehensive rating system that assessed twenty factors. Both of these procedures significantly decreased functional limitations and symptoms and improved the level of sports activity and the over-all score. However, the use of the ligament-augmentation device did not improve the efficacy of the reconstruction with regard to any of the individual variables that were assessed or in terms of the over-all score. All but one of the patients regained an arc of 0 to 135 degrees of motion. Although the augmentation device reduced anterior-posterior displacement effectively for the first twenty weeks postoperatively (p less than 0.05), there was no difference between the groups in terms of the percentage of knees that had abnormal displacement at the latest follow-up. A new classification system was developed to determine rates of failure. The over-all rate of failure was 28 per cent (thirty-two) of the 115 knees: 29 per cent (nineteen) of the sixty-six knees in Group BLB and 27 per cent (thirteen) of the forty-nine knees in Group BLB-LAD. The difference between the two groups was not statistically significant. The addition of the ligament-augmentation device did not improve the results of allograft reconstruction in the treatment of chronic rupture of the anterior cruciate ligament. The use of either an allograft alone or an allograft combined with a ligament-augmentation device did not reduce the amount of anterior-posterior displacement satisfactorily in all of the knees.

Adolescent↗
PubMed1993

The name cranial ovarian suspensory ligaments in mammalian anatomy should be used only to indicate the structures derived from the foetal cranial mesonephric and gonadal ligaments.

The term ovarian suspensory ligament appears ambiguous when human adult anatomy textbooks are compared with human embryology or with general mammalian anatomy textbooks. The term ovarian suspensory ligament in laboratory rodents and domestic animals indicates homologous structures during foetal (the cranial mesonephric and gonadal ligaments) and later life (the cranial mesonephric ligament derivatives). In human foetal anatomy textbooks ovarian suspensory ligament is generally applied to this same ligament. However, in human adult anatomy textbooks ovarian suspensory ligament is widely applied to the part of the (uterine) broad ligament which contains the uterine and ovarian blood and lymphatic vessels and nerves. This inconsistency in human anatomy books raises confusion on the nature of the foetal and adult ovarian suspensory ligaments and inconsistencies in the description of the normal anatomical relationships of the ovaries between humans and other mammals. For the proper understanding of normal gonadal growth and development within the abdomen, it is important to maintain a consistent nomenclature of the cranial ovarian structures. The current practice in veterinary and other mammalian textbooks offers a solid point of departure.

Animals↗