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A "mini-reconstruction" technique in treating anterolateral rotatory instability (ALRI).

A "mini-reconstruction" for ALRI, utilizing isometric bundles in the iliotibial tract, has been employed in 62 knee injuries--31 acutely injured and 31 chronically unstable knees. Evaluated at two or more years after operation, the results have been gratifying. The procedure should not be used for chronic "global instability" The technique is extra-articular, closely approximates the functions of the anterior cruciate ligament (ACL), and is static. Maximum tensile strength is attained early in the postoperative recovery period.

Fascia↗

Observations on the structure and the biomechanics of the cricothyroid articulation.

We examined quantitatively the ventrodorsal gliding occurring along a sagittal plane in the cricothyroid articulation. For this purpose we used 10 fresh excised human larynges taken at autopsy. Furthermore we examined the morphology, the hydroxyproline content and collagen types of the ligaments and the articular capsule of the cricothyroid articulation. This articulation appeared to be a synovial joint, supported by two ligaments: the lateral and posterior ceratocricoid ligament and articular capsule. The ligaments and the capsule contained both type I and type III collagen fibres and they were rich in elastin fibres 1-2.5 microns in diameter. Ventrodorsal gliding was generally possible when the joint was not rotated to its extremes. The marked individual variation was not essentially affected by sex or age. The collagen content of the lateral ceratocricoid ligament showed a statistically significant negative correlation with the gliding. The articular facet of the cricoid cartilage, which was not usually well-shaped, limits the gliding. A force of +/- 1.0 N caused on the average a change of +/- 1.0 mm in the length of the vocal cord. Further research is needed to evaluate the physiological importance of these findings.

Aged↗

The effects of estrogen on material and mechanical properties of the intra- and extra-articular knee structures.

BACKGROUND: Female athletes have a higher incidence of anterior cruciate ligament injuries than do male athletes in similar sports. Hormones, particularly estrogen, have been indicated by some studies to be correlated with the disproportionate number of anterior cruciate ligament injuries in female athletes. HYPOTHESIS: Estrogen does not affect the mechanical or material properties of primate anterior cruciate ligaments or patellar tendons. STUDY DESIGN: Controlled laboratory study. METHODS: Twenty-six cynomolgus monkeys (Macaca fascicularis) were divided into 2 groups: sham operated (estrogen maintained, n = 12) and ovariectomized (estrogen deficient, n = 14). After 2 years, the animals were sacrificed, and various properties of ligaments were tested. Two different ligaments were studied, the anterior cruciate ligament and patellar tendon. RESULTS: No differences were found between the sham-operated (sham) and ovariectomized group for failure load (anterior cruciate ligament: sham, 394 +/- 67 N; ovariectomized, 392 +/- 96 N; P > .74), stiffness, elongation at failure, ultimate stress (anterior cruciate ligament: sham, 115 +/- 30 MPa; ovariectomized, 128 +/- 36 MPa; P > .58), ultimate strain, modulus, failure sites, or energy to failure. CONCLUSION: Endogenous estrogen does not directly affect the mechanical or material properties of the anterior cruciate ligament or the patellar tendon of cynomolgus macaques. CLINICAL RELEVANCE: This study supports the idea that knee ligament injury in female athletes is not a direct result of estrogen's effect on ligament properties.

Animals↗

Articular and osseous lesions in recent ligament tears: arthroscopic changes compared with magnetic resonance imaging findings.

The treatment of ligament injuries of the knee has undergone rapid progress, especially with the improvement of arthroscopic reconstruction of the anterior cruciate ligament (ACL). Since the advent of magnetic resonance imaging (MRI) after knee trauma with ligament injuries, interest has focussed on the clinical significance of concomitant articular and osseous lesions. In 48 of 141 MRIs, different types of these lesions were found; in 38 cases an arthroscopy was performed and 34 times the patients could clinically and radiologically be examined after at least 6 months. Bone bruise was found 26 times, in 16 cases associated with ACL-tears. Eleven patients had subchondral fractures, 7 osteochondral fractures, and in 4 patients, stress fractures were found. They were attributed to various mechanisms of trauma, in different percentages associated with ligament tears and in different dimensions visible or progressive on follow-up MRIs. Obviously some of the different lesions of subchondral and spongeous bone can indicate later degenerative arthritis, so that we find hints for a modification of rehabilitation, e.g., open versus closed kinetic chain or orthosis with relief of single compartments.

Adolescent↗

Comparison of 1- and 2-incision posterior cruciate ligament reconstructions.

This study compared the results of the 1-incision technique and the conventional 2- incision technique for the arthroscopic treatment of the posterior cruciate ligament (PCL) injury. The 2-incision technique was performed in 10 patients (group I) and the 1-incision technique in 45 patients (group II). The average duration of follow-up was 45 months in group I and 36 months in group II. Bone-patellar tendon-bone (BTB) autografts were used for all patients in group I. In group II, 34 BTB autografts and 11 BTB allografts were used. Postoperative Lysholm mean values were 90.0 in group I and 90.6 in group II. HSS mean values were 87.7 in group I and 92.6 in group II (P = .037). The Tegner activity level scales were 6.4 in group I and 6.5 in group II. The average side-to-side difference of the corrected posterior translation measured by the KT-2000 arthrometer were 2.10 mm in group I and 2.38 mm in group II. There were no statistically significant differences between the 2 groups in postoperative mean values except HSS scores. The arthroscopic PCL reconstruction using the 1-incision technique showed good results comparable with the conventional 2-incision technique. This technique needs no another incision or dissection over the medial femoral condyle.

Adolescent↗

Degenerative joint disease in the mouse knee; histological observations.

The knee joints from males of two strains (CBA/ORT and STR/ORT) were studied histologically. The incidence of degenerative joint disease was very high in the STR/ORT strain. Degeneration of the cartilage invariably occurred first at the interface of the cruciate ligament and articular cartilage of the tibia. Lesions were only seen on the medial tibial and later the medial femoral condyles. Blocks of fibrillated, uncalcified cartilage were gradually lost across the condyle, leaving the tidemark as a secondary articulating surface. Meanwhile the subchondral bone thickened and erosion continued through the calcified cartilage into the underlying bone. A statistically significant relationship was found between the development of the lesion and (a) medial dislocation of the patella, (b) calcification and ossification of the medial collateral ligament. Patella dislocation gave rise to extensive cartilaginous and bony metaplasia of the synovial tissue. In joints with advanced degeneration there was often evidence of a slight lateral subluxation of the femur relative to the tibia.

Aging↗

Extra-articular tenodesis for anterior cruciate ligament rupture in amateur skiers.

Thirty one amateur skiers with 33 knees which had had a symptomatic chronic rupture of the anterior cruciate ligament (ACL) treated with the Lemaire operation were reviewed retrospectively at an average of 4.5 years. Of the patients 23 were women. The operation failed to control symptoms in 17 out of the 33 knees. However the operation did control symptoms in 13 out of 19 knees in patients over 35 years old, compared with only three out of 14 knees in patients under 35 years old. Clinical and objective testing however showed that most knees were still unstable. Despite this 21 patients continued skiing. One patient with a successful result switched to playing tennis. Five patients gave up all sports. Four further patients, all under 35 years old, returned to skiing after an additional intra-articular reconstruction of the anterior cruciate ligament. An isolated extra-articular procedure in amateur skiers under 35 years old with symptomatic chronic ACL rupture is not recommended. They need at least an intra-articular reconstruction to control their symptoms and to stabilize the knee.

Adolescent↗

Variability of extraarticular tibial rotation references for total knee arthroplasty.

Anatomic reference axes that determine rotational alignment of the tibial component have not been established. To assess variability of three anatomic reference axes (a new tibial anteroposterior axis that we proposed, the transmalleolar axis of the ankle, and the second metatarsus bone axis of the foot), we measured the angles between a defined anteroposterior axis of the tibia (a line perpendicular to the transepicondylar axis) and each of the three axes in 57 knees of healthy subjects using computed tomography scans. The angle between the defined anteroposterior axis and our proposed anteroposterior axis (a line connecting the middle of the posterior cruciate ligament and the medial edge of the patellar tendon attachment) averaged -0.2 degrees +/- 2.8 degrees (range, -5.5 degrees -6.3 degrees). The angle between the defined anteroposterior axis and the transmalleolar axis averaged 25.9 degrees +/- 9 degrees (range, 8 degrees -49.4 degrees), and the angle between the defined anteroposterior axis and the second metatarsus bone axis averaged 5.2 degrees +/- 10 degrees (range, -21.9 degrees -24 degrees). The variability of the anteroposterior axis was less than than the other reference axes. These data indicate that our proposed tibial anteroposterior axis is more reliable for determining rotational alignment of the tibial component in total knee arthroplasty.

Adult↗

Arthroscopic assessment of occult intra-articular injury in acute ankle fractures.

PURPOSE: To arthroscopically assess the pattern and extent of intra-articular damage associated with ankle fractures. TYPE OF STUDY: Prospective case series. METHODS: From 1989 to 1998, 48 consecutive patients with acute unstable ankle fractures underwent ankle arthroscopy followed by reduction and internal fixation. In addition, all injuries were categorized by specific osseous, ligamentous, and articular pathology, based on clinical and arthroscopic examination. Whenever possible, the fractures were classified according to Lauge-Hansen and Danis-Weber schemes. RESULTS: Traumatic articular surface lesions (TASLs), including chondral defects and osteochondral lesions measuring greater than 5 mm in diameter, were identified in 30 of the 48 ankles (63%), with 11 lesions localized to the tibia and 19 noted on the talus. The tibial lesions were at the posterior syndesmotic ligament insertion in 6 cases, at the anterior capsule origin in 3 cases, and at the central articular surface in 2 cases. Of the 19 talar lesions, 15 involved the medial dome and 4 involved the lateral articulation. TASLs of the talus in this series were uniformly unstable or displaced and virtually devoid of subchondral bone, precluding satisfactory internal fixation. Of the 10 pronation-external rotation fractures, 7 had articular surface defects with 5 involving the medial and 2 the lateral dome. Ten of the 24 supination-external rotation or Danis-Weber B fractures were found to have TASLs of the talus, 9 medial and 1 lateral. Nine of 12 fractures with syndesmosis disruptions sustained full-thickness damage to the talar chondral surface (P =.01). CONCLUSIONS: Ankle fractures have a high incidence of concomitant intra-articular pathology with syndesmosis disruption portending a particularly high risk of articular surface injury to the talar dome. Arthroscopy is a valuable tool in identifying and treating intra-articular damage that would otherwise remain unrecognized and may provide prognostic information regarding the functional outcome of these injuries.

Acute Disease↗

Nonuniform distribution of collagen density in human knee ligaments.

It is generally recognized that the mechanical properties of soft connective tissues are affected by their structural components. We documented collagen density distributions in human knee ligaments to quantify differences in density within and between these ligaments. In order to explain the variations in mechanical properties within and between different knee ligaments as described in the literature, the distributions of collagen density were correlated with these biomechanical findings. Human knee ligaments were shown to be nonhomogeneous structures with regard to collagen density. The anterior bundles of all ligaments contained significantly more collagen mass per unit of volume than the posterior bundles did. The percentage differences between the anterior and posterior bundles, in relation to the posterior bundles, were about 25% for the anterior cruciate ligament (ACL) and the collateral ligaments and about 10% for the posterior cruciate ligament (PCL). Along the cruciate ligaments, the central segments had higher collagen densities than did segments adjacent to the ligament insertions (ACL 9%, PCL 24%). The collagen density in the ACL was significantly lower than that in the other ligaments. These variations within and between the ligaments correlate well with the variations in mechanical properties described in the literature; however, other structural differences have to be taken into account to fully explain the variations in mechanical properties from the structural components.

Aged↗

[The value of sonographic diagnosis of the injured knee joint in trauma-surgical practice].

In a period of two years (January 1990 to December 1991) 136 knee joints were examined by ultrasound and arthroscopy. 40 out of 42 arthroscopically proven lesions of the anterior cruciate ligament were detected by ultrasound. The sensitivity therefore was 95.24%. We found three cases of ruptures of the posterior cruciate ligament, which were not detected clinically. 16 cases of ruptured medial collateral ligaments and 27 cases of elongations of the same ligament were diagnosed. Ultrasound examination of the knee and especially of the cruciate ligaments showed to be an accurate tool in order to obtain additional information on an injured knee even if clinical examination is difficult or impossible. Sonography is able to exclude lesions of the cruciate ligaments precisely. Therefore it helps to restrict the necessity of acute or early arthroscopy of knee joints.

Anterior Cruciate Ligament↗

Biomechanics of the PCL and related structures: posterolateral, posteromedial and meniscofemoral ligaments.

This paper reviews and updates our knowledge of the anatomy and biomechanics of the posterior cruciate ligament, and of the posterolateral, posteromedial and meniscofemoral ligaments of the knee. The posterior cruciate ligament is shown to have two functional fibre bundles that are tight at different angles of knee flexion. It is the primary restraint to tibial posterior draw at all angles of knee flexion apart from near full extension. In contrast, the posterolateral and posteromedial structures are shown to tighten as the knee extends, and to be well-aligned to resist tibial posterior draw. These structures also act as primary restraints against other tibial displacements. Tibial internal rotation is restrained by the medial and posteromedial structures, while tibial external rotation is restrained by the lateral and posterolateral structures. They are also the primary restraints against tibial abduction-adduction rotations. The meniscofemoral ligaments are shown, for the first time, to contribute significantly to resisting tibial posterior draw, and to have a strength of approximately 300 N. Taken together, this evidence shows how the posterolateral and posteromedial structures are responsible for posterior knee stability near extension, and this, along with the action of the meniscofemoral ligaments, may explain why an isolated rupture of the posterior cruciate ligament does not often lead to knee instability

Biomechanical Phenomena↗

MR imaging of the knee in marathon runners before and after competition.

OBJECTIVE: To evaluate the findings in MRI-studies of the knee in recreational long-distance runners after competition and to assess the reversibility of the findings. DESIGN AND PATIENTS: Eight recreational long-distance runners underwent MRI studies of the knee before, immediately after and 6-8 weeks after taking part in the Vienna City Marathon. The studies were evaluated regarding alterations of pre-existing lesions and new pathological findings. RESULTS: In six runners without major pre-existing alterations no negative effects were experienced. In one runner with pre-existing grade III alterations of the menisci, signs of progressive osteoarthritis were experienced 2 months after the competition. In all other cases increased meniscal signal alterations and minor signal changes in the bone marrow after the race were transitory. CONCLUSION: In healthy individuals no negative long-term-effects were experienced. Pre-existing high-grade lesions of the menisci might be a predisposing risk for osteoarthritis, triggered by the stress of long-distance running.

Adult↗

The effect of variable relative insertion orientation of human knee bone-ligament-bone complexes on the tensile stiffness.

In order to evaluate the contribution of the knee ligaments to restrain joint motions, knowledge about their structural properties is required. Due to the variable relative insertion orientation of the ligaments during knee motion, however, different fiber bundles are recruited, each with their specific mechanical properties. Hence, the structural properties vary as a function of knee motion. For this reason, a relationship between the structural tensile properties and the relative insertion orientation is required in order to define the role of the ligaments in knee mechanics. In the present study, this relationship is determined by performing a series of tensile tests in which the relative orientations of the insertion sites of human knee bone-ligament-bone preparations were varied systematically. The experimentally obtained stiffness was significantly affected by the relative orientation of the insertion sites, but more profoundly for the anterior and posterior cruciate ligaments (ACL and PCL) as compared to the medial and lateral collateral ligaments (MCL and LCL). The average decreases in stiffness per 5 degrees tilt of the insertion sites were estimated at -11.6 +/- 3.5 N mm-1 (ACL), -20.9 +/- 2.7 N mm-1 (PCL), -2.6 +/- 0.9 N mm-1 (MCL) and -3.7 +/- 0.3 N mm-1 (LCL). For the PCL and the MCL these changes in stiffness with tilt were rather insensitive to the side of the femoral insertion site which was lifted. The ACL and the LCL, conversely, displayed significant differences in stiffness changes between the different tilt directions.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

Centric relation as the treatment position.

Centric relation should be considered as "the most superior position of the mandibular condyles with the central bearing area of the disk in contact with the articular surfaces of the mandibular condyles and the articular eminences." This relationship is justifiable on analysis of the morphology and function of temporo-mandibular joint structures.

Cartilage, Articular↗

The posterolateral corner of the knee: evaluation under microsurgical dissection.

PURPOSE: The posterolateral corner (PLC) has been described by several authors, but there are still controversies. We assumed that a microanatomic dissection of this region could answer some of the questions about its complex anatomy. We therefore conducted an anatomic study using microsurgical techniques, aiming at a precise anatomic description of all the structures that form the posterolateral complex. TYPE OF STUDY: Cadaveric study. METHODS: Ten fresh-frozen human adult cadaveric knees were used for the study. Dissection of the knees was performed using microsurgical instruments, magnifying loupes, and an operative microscope. Anatomic variations, ligament shape, separated bundles of the ligaments, and topography of ligament attachments were described and recorded. RESULTS: The rate of the presence of the popliteofibular ligament (PFL), the fabellofibular ligament, and the arcuate ligament were 100%, 40%, and 70%, respectively. The connective attachments of the popliteus muscle to the other posterolateral structures are the PFL and the 2 popliteomeniscal fascicles. Our dissections show that the shape and the fibula attachment of the PFL can vary. Using the surgical microscope, we were able to dissect and identify 2 different fiber groups of the popliteus tendon at its attachment to the lateral femoral condyle. Also, we were able to confirm in 20% of our knees an anatomic variation of the lateral collateral ligament. CONCLUSIONS: Our study may answer some of the questions about the complex anatomy of the PLC. The PFL is well established, always recognizable, and significant in size. CLINICAL RELEVANCE: Being aware of the complex anatomy of the posterolateral corner and its variations may prove useful in repair and reconstruction.

Adult↗

Osteoarthritis after sports knee injuries.

Recent advances in the knowledge of tissue homeostasis, including the tissue homeostasis theory and the envelope of function theory as proposed by Dye, have greatly increased our knowledge of the pathophysiology of osteoarthrosis after sports knee injuries. The development of these two theories has not only advanced our understanding of the treatment and prevention of osteoarthrosis after acute injuries to the knee, but has also given us guidance as to directions for future research.

Athletic Injuries↗