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PubMedDate not supplied

Capsular ligaments of the shoulder. Anatomical and functional study of the anterior superior capsule.

One hundred shoulders of 50 cadavers were dissected using the anterior approach. The normal appearance of the capsule, particularly the anterior superior, and the functions of the structures during passive motion were noted. There was a distinct capsular pattern with a Z formation which included the coracohumeral ligament and the superior, middle, and inferior glenohumeral ligaments. The middle and proximal capsular structures appeared to restrain external rotation. The coracohumeral ligament aided in restraint of external rotation at the lower range of abduction. The middle glenohumeral ligament was critical in restraining external rotation between 60 degrees and 90 degrees of abduction. It was readily identifiable except in a small percentage of individuals, who had a weak or absent ligament. The large capsular opening sometimes seen in shoulder repairs is due to an absent or attenuated middle glenohumeral ligament. Both the coracohumeral and middle glenohumeral ligaments were found to support the dependent arm.

Adolescent↗
PubMedDate not supplied

The anatomy and histology of the inferior glenohumeral ligament complex of the shoulder.

The gross and histologic anatomy of the inferior glenohumeral ligament was studied in 11 fresh frozen cadaver shoulders. Arthroscopic observations of the joint capsule through the normal range of motion revealed that the inferior glenohumeral ligament is actually a complex of structures consisting of an anterior band, a posterior band, and an interposed axillary pouch. While these components of the inferior glenohumeral ligament complex were present in all 11 specimens, they were best demonstrated in some shoulders by placing the humeral head in internal or external rotation in varying degrees of abduction. Histologic examination of the joint capsule revealed that the anterior and posterior bands of the inferior glenohumeral ligament complex were readily identifiable as distinct structures comprised of thickened bands of well-organized collagen bundles. Although slight variations were noted in the attachment sites of the anterior and posterior bands to the glenoid, the inferior glenohumeral ligament complex was observed to attach to the humeral neck in one of two distinct configurations. A collar-like attachment, in which the entire inferior glenohumeral ligament complex attaches just inferior to the articular edge of the humeral head, was observed in six specimens. In the remaining five specimens, the attachment was in the shape of a "V," with the anterior and posterior bands attaching adjacent to the articular edge of the humeral head and the axillary pouch attaching at the apex of the "V" distal to the articular edge. The orientation and design of the inferior glenohumeral ligament complex supports the functional concept of this single structure as an important anterior and posterior stabilizer of the shoulder joint.

Arthroscopy↗
PubMedDate not supplied

The effects of increased tension on healing medical collateral ligaments.

The effects of motion and increased levels of stress on the biomechanical, biochemical, and morphological properties of healing medial collateral ligaments were assessed in a rabbit model. In one group, the medial collateral ligament of the left hindlimb was transected and allowed to heal with cage activity for either 6 or 12 weeks. In another group, the transected ligaments were permitted to heal for 4 weeks and then were placed under increased stress by inserting a stainless steel pin perpendicularly underneath the healing medial collateral ligament. The animals were allowed cage activity for an additional 2 or 8 weeks. The varus-valgus joint laxity and the stress-strain properties of the medical collateral ligament substance were obtained. Further, the quantity of total collagen, amount and ratio of the collagen cross-links, dihydroxylysinonorleucine and hydroxylysinonorleucine, and the histologic appearance of the healing medical collateral ligaments were evaluated for all groups. At 6 weeks, knees with a transected medial collateral ligament were twice as lax as the controls. However, joints with the stainless steel tension pin had varus-valgus values approximately 1.5 times those of the controls. At 12 weeks, joints with increased stress were not statistically different from the controls. The group that had healing with increased stress for 12 weeks produced the highest stress for a given strain compared to any other group. Also, the total collagen levels and the ratio of dihydroxylysinonorleucine/hydroxylysinonorleucine were the closest to normal of any transected group. Finally, qualitative histologic improvements were seen, including a more longitudinal arrangement of collagen fibers and decreased cellularity.

Animals↗
PubMedDate not supplied

Force displacement characteristics of the posterior cruciate ligament.

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, posterior distal, anterior distal, and posterior distal direction. The tibial insertion sites were also varied 2.5 and 5.0 mm in the medial, lateral, proximal, and distal directions. Percent force changes were measured over a range of 0 degree to 90 degrees. 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 degree and 90 degrees 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 degrees and 75 degrees 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.(ABSTRACT TRUNCATED AT 250 WORDS)

Biomechanical Phenomena↗
PubMedDate not supplied

Magnetic resonance imaging of injury to the lateral ankle ligaments.

To establish the value of magnetic resonance imaging in determining which patients with ankle sprains will benefit from surgical treatment, 1 uninjured volunteer and 15 patients with acute, subacute, and chronic injuries of the lateral ankle ligaments were imaged at 1.0 tesla using a fast imaging with steady-state precision three-dimensional technique and 1.5-mm slice thickness. A dedicated knee coil was used to hold the foot in a neutral or plantar-flexed position. In cases of acute, low-grade injuries, fraying of the anterior talofibular ligaments with intact calcaneofibular ligaments was observed in the presence of edema and hemorrhagic fluid. In cases of acute, high-grade sprains, the calcaneofibular ligament appeared wavy or was visualized only partially or not at all. Subacute injuries showed ligament disruption; chronic lesions, on occasion, showed atrophy of the calcaneofibular ligament but no edema or hemorrhagic fluid. These findings showed a good qualitative correlation with the results of graded stress radiography. Magnetic resonance imaging can definitely determine the ligaments involved in lateral ankle sprains and provide useful anatomic information in cases in which acute or reconstructive surgery is contemplated. However, the magnetic resonance imaging findings do not directly correlate with degree of instability and do not replace those of physical examination or routine radiographic studies.

Acute Disease↗
PubMedDate not supplied

Undersurface tear of the ulnar collateral ligament in baseball players. A newly recognized lesion.

Seven patients were diagnosed with an undersurface tear of the deep capsular layer of the anterior bundle of the ulnar collateral ligament. Preoperatively, all of the patients had tenderness over the anterior bundle of the ulnar collateral ligament and pain with valgus stressing of the elbow. Six of the seven patients had a normal magnetic resonance imaging scan, with one magnetic resonance imaging scan showing degeneration within the ligament. All of the patients had a negative computed tomography arthrogram for extracapsular contrast extravasation. A consistent finding in five of the seven patients was a leak of contrast around the edge of the humerus or ulna, although the contrast was contained within the joint. At arthroscopic evaluation, all of the patients demonstrated medial elbow instability as valgus stress was applied across the elbow joint in 70 degrees of flexion. All of the patients underwent open medial elbow surgery, where the ulnar collateral ligament was visualized and found to be intact externally. But when the anterior bundle was incised, there was a detachment of the undersurface of the ligament at the ulna or the humerus. Cadaveric dissections were performed to define the anatomy of the insertion sites and to confirm that this lesion was not an anatomic variant. A tear of the deep layer of the ulnar collateral ligament can result in symptomatic instability that is difficult to diagnose with conventional preoperative testing. This lesion of the anterior bundle of the ulnar collateral ligament has not been previously reported, and in our series it was associated with persistent medial elbow pain in throwing athletes.

Adult↗
PubMedDate not supplied

Anatomy of the lateral ankle ligaments.

The anatomy of the lateral ankle ligaments that is frequently described in articles and book chapters often lacks the precision of orientation and attachment points. We believe a knowledge of this precise anatomy is important to better reconstruct or repair lateral ligaments. We dissected cadaveric ankles free of skin and soft tissue and made the following measurements: areas of attachments of the anterior talofibular ligament, length and width of the anterior talofibular ligament, and locations of the attachments on the fibula and talus. The same measurements were made of the calcaneofibular and posterior talofibular ligaments. The distance of the calcaneofibular calcaneal attachments from the subtalar joint as well as the angle in the sagittal plane with the fibula was determined. We then used these anatomic attachments of the ligaments to make comparisons with the Watson-Jones and modified Elmslie reconstructions. Our results enable us to suggest a more anatomic placement for ligaments in a reconstruction.

Ankle Joint↗
PubMedDate not supplied

Histology and arthroscopic anatomy of the ulnar collateral ligament of the elbow.

The histology and arthroscopic anatomy of the ulnar collateral ligament of the elbow were studied in cadaveric specimens. The capsule consists of two layers of collagen fibers, with two distinct ligamentous bundles corresponding to anterior and posterior portions of the ulnar collateral ligament. The posterior bundle consists of distinct collagen bundles within the layers of the capsule; the anterior bundle consists of a similar thickening within the capsular layers, with an additional ligament complex superficial to the capsular layers. With arthroscopy only the anterior 20% to 30% of the anterior bundle of the ulnar collateral ligament could be visualized via the anterior portal. Only the posterior 30% to 50% of the posterior bundle could be seen via the posterior portals. After sectioning of the anterior bundle, joint instability was noted arthroscopically by an increased opening in the ulnohumeral joint with application of valgus stress. At arthroscopy ulnar collateral ligament tears may be visualized in part or not at all. To diagnose a tear or laxity in the ulnar collateral ligament, a demonstration of an increase in the opening of the ulnohumeral joint in response to valgus stress is useful.

Arthroscopy↗
PubMedDate not supplied

Dynamic ankle ultrasonography. A new imaging technique for acute ankle ligament injuries.

We have developed a noninvasive ultrasound technique that may be used to differentiate complete and incomplete acute tears of the anterior talofibular ligament. Direct visualization of the ligament will demonstrate the lesion in most cases and can be supplemented by an anterior drawer test with the ligament under direct vision. Seventeen athletes involved in sports and work that put high-demand pressure on their ankles underwent ultrasonic examination of their acute lateral ankle ligament injuries before surgical exploration. Fourteen scans demonstrating a complete lesion of the anterior talofibular ligament were confirmed at operation. Three scans were equivocal; two of these patients had incomplete lesions of their anterior talofibular ligaments and one patient had a complete tear that was not detected. We have found that the dynamic ultrasound test is a simple and reliable examination. We suggest that this technique is indicated where the extent of an acute lateral ligament injury requires further definition. Ankle ultrasonography may reduce the need for ankle arthrography.

Adolescent↗
PubMedDate not supplied

Critical analysis of knee ligament rating systems.

Sixty-five patients who consecutively underwent anterior cruciate ligament reconstruction were studied using four individual, categoric, knee score rating systems. Different results were noted at followup (mean, 35 months; range, 24 to 58) depending on the rating method used. Ali patients were graded using the Hospital for Special Surgery, Lysholm, Tegner activity, and Cincinnati Knee Ligament rating systems. The Cincinnati Knee Ligament rating individual scores were noted to be lower than the Hospital for Special Surgery and Lysholm scores for subjective and objective outcome assessment. The Hospital for Special Surgery and Lysholm scores did not correlate highly with the Cincinnati Knee Ligament rating final rating, but they did correlate with each other. The use of ligament rating scores tended to inflate results, particularly when raw scores were converted to overall categoric ratings (e.g., excellent, good). The Cincinnati Knee Ligament rating system correlates more highly with individual grading and most precisely defines outcome in athletically active patients. Sources of error may be introduced by a disproportionate combination of unrelated scores or by overrating low-activity-level individuals who avoid stressing their knees. Avoidance of data generalization remains the optimal method for studying anterior cruciate ligament surgery outcome.

Activities of Daily Living↗
PubMedDate not supplied

Assessment of posterior cruciate ligament graft performance using robotic technology.

We used the information on in situ forces provided by robotics to compare two methods of posterior cruciate ligament graft fixation. Twenty porcine knees were studied using robotic technology to determine and repeat intact, deficient, and reconstructed knee motion under 110 N of posterior tibial loading at 30 degrees, 60 degrees, and 90 degrees of knee flexion. Reconstruction was performed using a bone-patellar tendon-bone graft with the distal end of the graft placed in the posterolateral aspect of the posterior cruciate ligament tibial insertion. Specimens were separated into two groups based on the femoral fixation site: the proximal or anterior aspect of the femoral insertion. Repetition of knee motion allowed measurement of the force in the intact posterior cruciate ligament and graft using the principle of superposition. The forces in the graft and the intact ligament provided additional information to evaluate graft performance. Force in the intact posterior cruciate ligament was significantly greater at 90 degrees than at 30 degrees and 60 degrees of knee flexion. The forces in both graft types were significantly lower than those of the posterior cruciate ligament, but the force in the anteriorly placed graft was significantly greater at 90 degrees than at 30 degrees and 60 degrees of knee flexion, similar to the intact posterior cruciate ligament. Thus, the anteriorly placed graft had a more physiologic increase in tension with knee flexion, when the joint provided less restraint.

Animals↗
PubMedDate not supplied

Intercondylar notch width and its relation to the configuration and cross-sectional area of the anterior cruciate ligament. A cadaveric knee study.

If a narrow intercondylar notch contains a smaller anterior cruciate ligament, that may explain why people with narrow notches have a higher incidence of anterior cruciate ligament injuries. To investigate the significance of notch width measurement, we used 16 embalmed cadaveric knees. A positive mold of the entire anterior cruciate ligament, including its femoral and tibial insertions, was created with silicone rubber and plaster commonly used for dental molding. We had two hypotheses to test from this study. One was that the dimensions of the anterior cruciate ligament can be predicted by the notch width. The other was that the size of a person's anterior cruciate ligament can be predicted by a caliper measurement of the intercondylar notch. The width, sagittal length, and cross-sectional area of the midsubstance and the femoral and tibial insertions of the anterior cruciate ligament were measured. The notch width index, the ratio of notch width to width of the femoral condyle, showed a positive correlation only to the ratio of width to sagittal length of the tibial insertion. None of the parameters showed any differences between the knees with a notch width index less than or equal to 0.2 and those with a notch width index greater than 0.2. The knees with small notch width indexes did not have thinner anterior cruciate ligaments in them. These findings may not be applicable to knees obtained from other races, i.e., not Japanese.

Aged↗
PubMedDate not supplied

Isometry measurements in the knee with the anterior cruciate ligament intact, sectioned, and reconstructed.

When assessing isometry during anterior cruciate ligament surgery, it is assumed that points determined to be isometric remain so after reconstruction. We sought to evaluate if isometric measurements vary with the status of the anterior cruciate ligament. A computerized electronic isometer was used to measure the magnitude and pattern of change in separation distance between a constant point in the tibial insertion of the anterior cruciate ligament and five positions within the femoral insertion with the anterior cruciate ligament intact, sectioned, and reconstructed. For the center position, the magnitude and pattern of the change in separation distance was physiologically isometric in all conditions (maximal length change, 3.0 mm). For the posterior position, the isometry pattern remained physiologic in each condition, and the magnitude of the separation distance was nearly isometric in all conditions (maximal length change, 3.7 mm). The superior and inferior positions had similar isometric measurements in the intact and sectioned conditions but significantly different measurements after anterior cruciate ligament reconstruction. Intraoperative assessment of isometry at positions in the center or posterior portion of the anterior cruciate ligament's femoral insertion provides useful information that is not altered by reconstruction. For superior and inferior positions, however, points found to be isometric in the anterior cruciate ligament-deficient knee did not remain isometric after reconstruction.

Anterior Cruciate Ligament↗
PubMedDate not supplied

Biomechanics of ankle ligament reconstruction. An in vitro comparison of the Broström repair, Watson-Jones reconstruction, and a new anatomic reconstruction technique.

We wanted to use biomechanical testing in a cadaveric model to compare the Broström repair, the Watson-Jones reconstruction, and a new anatomic reconstruction method. Eight specimens were held in a specially designed testing apparatus in which the ankle position (dorsiflexion-plantar flexion and supination-pronation) could be varied in a controlled manner. Testing was done with intact ligaments and was repeated after sectioning of the anterior talofibular ligament and the calcaneofibular ligament and after a Broström repair, a Watson-Jones reconstruction, and a new anatomic reconstruction were performed. An anterior drawer test was performed using an anterior translating force of 10 to 50 N, and a talar tilt test was performed using a supination torque of 1.1 to 3.4 N-m. The forces in the anterior talofibular ligament and calcaneofibular ligament were measured with buckle transducers, and tibiotalar motion and total ankle joint motion were measured with an instrumented spatial linkage. The increase in ankle joint laxity observed after sectioning of both the anterior talofibular and calcaneofibular ligaments was significantly reduced by the three reconstructive techniques, although not always to the level of the intact ankle. Joint motion was restricted after the Watson-Jones procedure compared with that in the intact ankle. Unlike the Watson-Jones procedure, the ligament or graft force patterns observed during loading after the Broström repair and the new anatomic technique resembled those observed in the intact ankle.

Adult↗
PubMedDate not supplied

The strain behavior of the anterior cruciate ligament during squatting and active flexion-extension. A comparison of an open and a closed kinetic chain exercise.

The effects of weightbearing (closed kinetic chain) and nonweightbearing (open kinetic chain) exercises on the biomechanical behavior of an injured anterior cruciate ligament or a healing anterior cruciate ligament graft are unknown. To understand the effects of these exercises on the healing graft, we measured the strain behavior of the normal anterior cruciate ligament in human subjects while they performed squatting, a closed kinetic chain exercise, and active flexion-extension of the leg, an open kinetic chain exercise. The maximum anterior cruciate ligament strain values obtained during squatting did not differ from those obtained during active flexion-extension. Also, anterior cruciate ligament strain values obtained during squatting were unaffected by the application of elastic resistance intended to increase muscle activity. These findings indicate that squatting, which produces a substantial compressive joint force, does not necessarily protect the anterior cruciate ligament more than active flexion-extension of the leg, which is characterized primarily by contraction of the dominant quadriceps muscle. These findings also demonstrate that increasing resistance during the squat exercise does not produce a significant increase in anterior cruciate ligament strain values, unlike increased resistance during active flexion-extension exercise.

Adult↗
PubMedDate not supplied

Arthrometric evaluation of posterior cruciate ligament injuries.

We reviewed the clinical examinations and knee arthrometry evaluations of 40 patients: 10 with posterior cruciate ligament injuries, 10 with combination anterior and posterior cruciate ligament injuries, 10 with anterior cruciate ligament injuries alone, and 10 with no history of knee injury. Using a 3-mm side-to-side difference as the minimal limit for detection of posterior cruciate ligament injury, the sensitivity of the arthrometer at 40 pounds of posterior force was 90%, the specificity was 100%, the predictive value of a positive test was 100%, and the predictive value of a negative test was 91%. When total anterior-posterior translation was assessed, the sensitivity was 100%, the specificity was 85%, the predictive value of a positive test was 87%, and the predictive value of a negative test was 100%. The overall accuracy of arthrometry for detection of posterior cruciate ligament injury was 96% for 40 pounds of posterior force and 94% for total anterior-posterior translation at 40 pounds. Grade 1 posterior cruciate ligament injuries had significantly greater arthrometric posterior translation compared with grade 0 (normal) knees. Regression analysis showed arthrometric laxity measurements correlated well with the clinical grade of the posterior drawer test. Finally, the accuracy of the arthrometer was not affected by concomitant anterior cruciate ligament injury.

Adolescent↗
PubMedDate not supplied

The effects of removal and reconstruction of the anterior cruciate ligament on patellofemoral kinematics.

Patellofemoral pain may be associated with anterior cruciate ligament deficiency or may occur after anterior cruciate ligament reconstruction. We investigated the effects of the removal and reconstruction of the anterior cruciate ligament on the kinematics of the tibiofemoral and patellofemoral joints during physiologic levels of quadriceps muscle loads in seven cadaveric knees. A bone-patellar tendon-bone graft was used for intraarticular reconstruction of the anterior cruciate ligament. The spatial positions of the tibiofemoral and patellofemoral joints were measured between 0 degrees and 90 degrees of knee flexion in 15 degrees increments with a six degree-of-freedom digitizing system. Excision of the anterior cruciate ligament resulted in statistically significant increases in anterior tibial translation between 0 degrees and 90 degrees and valgus tibial rotation between 30 degrees and 90 degrees; intraarticular reconstruction returned these to levels not significantly different from those of the intact knee. Excision of the anterior cruciate ligament resulted in significant increases in lateral patellar tilt, ranging from 6.3 degrees to 9.0 degrees between full extension and 90 degrees of knee flexion, and in lateral patellar shift, ranging from 2.9 mm at 15 degrees of knee flexion to 5.9 mm at 90 degrees; intraarticular reconstruction returned these to levels not significantly different from those of the intact knee. Neither removal nor reconstruction of the anterior cruciate ligament significantly affected tibial internal-external rotation, patellar flexion, patellar mediolateral rotation, patellar anteroposterior translation, or patellar proximodistal translation.

Adult↗
PubMedDate not supplied

The effects of platelet-derived growth factor-BB on healing of the rabbit medial collateral ligament. An in vivo study.

We report a biologic approach to improve medial collateral ligament healing using growth factors normally expressed in healing tissue. Our previous in vitro work demonstrated that platelet-derived growth factor-BB and transforming growth factor-beta 1 promoted fibroblast proliferation and matrix synthesis, respectively. There-fore, these growth factors were used in vivo to determine whether they could improve medial collateral ligament healing, whether this effect was dose-dependent, and if combinations of growth factors could improve healing more than individual growth factors. Thirty-seven rabbits had various doses of growth factors applied to the ruptured right medial collateral ligaments using a fibrin sealant delivery vehicle. The five groups consisted of 1) two groups receiving two doses of platelet-derived growth factor-BB, 2) two groups receiving two doses of this growth factor plus transforming growth factor-beta 1, and 3) one group receiving fibrin sealant only. After sacrifice at 6 weeks, biomechanical and histologic evaluations of the healing ligament were performed. Femur-medial collateral ligament-tibia complexes of the knees given the higher dose of platelet-derived growth factor-BB had ultimate load, energy absorbed to failure, and ultimate elongation values that were 1.6, 2.4, and 1.6 times greater than the same complexes of the control group. Adding transforming growth factor-beta 1 did not lead to any further increase in the structural properties of the complex compared with treatment with platelet-derived growth factor-BB. These encouraging results suggest that use of platelet-derived growth factor-BB may improve the quality of the healing medial collateral ligament, and that it may also have a similar potential for promoting healing of other ligaments.

Analysis of Variance↗