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PubMedDate not supplied

[Dislocation of the tibia in lesions the of anterior cruciate ligament. A magnetic resonance measurement technic].

In the international scientific literature, MRI is reported to identify anterior cruciate ligament tears with high diagnostic accuracy (80-95%). In this prospective analysis, 274 MR examinations of the knee were performed to develop a method to measure even slight sagittal dislocation of the tibia relative to the femur as a predictor of an anterior cruciate ligament tear. Ninety-eight patients presented a healthy anterior cruciate ligament and were therefore considered as a control group. In 92 cases, a complete tear of the anterior cruciate ligament was observed; in 78 cases the injury was partial and in 6 cases the posterior cruciate ligament was injured. Our results had arthroscopic, surgical or clinical confirmation in all cases. The measurements were carried out on an MR image of the sagittal midplane of the knee and served to calculate a ratio (Y/X) which quantifies the degree of possible tibial dislocation. The results served to establish a range for classifying the status of the anterior cruciate ligament in three categories: 1) undamaged ligaments (Y/X < 3), 2) interstitial injury (2.2 < Y/X < 3) and 3) complete tear (Y/X < 2.2). This simple and easy-to-apply method should be considered complementary to conventional MR examinations. The results are extremely useful in the analysis of acute injuries where other radiologic and symptomatologic techniques are not completely reliable.

Anterior Cruciate Ligament↗
PubMed1998

Magnetic resonance imaging of the normal and injured lateral collateral ligaments of the ankle.

BACKGROUND AND AIMS: To study the role of MR Imaging in evaluating both normal and injured lateral collateral ligaments of the ankle. MATERIALS AND METHODS: Twenty-four patients with clinically diagnosed inversion injury to the ankle and 20 healthy volunteers underwent Magnetic Resonance Imaging (MRI) of the ankle with special emphasis on the lateral complex ligaments. RESULTS: The anterior talofibular (ATFL) and posterior talofibular ligaments (PTFL) were identified in 100% of the ankles of normal volunteers in the axial plane. The PTFL was identified in 100% in the coronal plane. The calcaneofibular ligament (CFL) was identified in 76% of the ankles in the axial, 84% in the coronal and 88% in the sagittal plane. Of the 24 patients with inversion injury, MRI showed ligament abnormalities in 16 patients, ten of these were isolated ATFL tears, five had combined ATFL and CFL tears and one case showed in addition abnormal signal in the PTFL. MRI revealed associated injuries to other ligaments and other soft tissue and osseous structures of the ankle in twelve patients. CONCLUSION: MRI is a non-invasive, accurate technique for evaluation of the normal and injured lateral collateral ligaments of the ankle.

Acute Disease↗
PubMed2007

Tendons and ligaments are anatomically distinct but overlap in molecular and morphological features--a comparative study in an ovine model.

Tendons and ligaments are similar in composition but differ in function. Simple anatomical definitions do not reflect the fact individual tendons and ligaments have unique properties due to their adaptation to a specific role. The patellar tendon is a structure of particular clinical interest. A null hypothesis was declared stating that the patellar tendon is not significantly different in terms of matrix composition and collagen fibril diameter to other tendons. The lateral and medial collateral ligaments (LCL, MCL), anterior and posterior cruciate ligaments (ACL, PCL), together with the long digital extensor, superficial digital extensor, and patellar tendons (LDET, SDFT, PT) were harvested from three cadaveric ovine hindlimbs. The extracellular matrix was assessed in terms of water, collagen, and total sulphated glycosaminoglycan (GAG) content. The organization of the collagen component was determined by an ultrastructural analysis of collagen fibril diameter distributions, together with values for the collagen fibril index (CFI) and mass-average diameter (MAD). There were significant differences between ligaments and tendons. The PT had a bimodal collagen fibril diameter distribution with CFI 72.9%, MAD 202 nm, water content 53.1%, GAG content 2.3 microg/mg, and collagen content 73.7%, which was not significantly different from the other tendons. The results of this study support the null hypothesis suggesting that the patellar tendon is similar to other tendons and demonstrate that tendons have different characteristics to ligaments.

Animals↗
PubMed1995

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↗
PubMed1997

A musculoskeletal model of the knee for evaluating ligament forces during isometric contractions.

A model of the knee in the sagittal plane was developed to study the forces in the ligaments induced by isometric contractions of the extensor and flexor muscles. The geometry of the distal femur was obtained from cadaver data. The tibial plateau and patellar facet were modeled as flat surfaces. Eleven elastic elements were used to describe the mechanical behavior of the anterior and posterior cruciate ligaments (ACL and PCL), the medial and lateral collateral ligaments (MCL and LCL), and the posterior capsule. The model knee was actuated by 11 musculotendinous units, each muscle represented by a Hill-type contractile element, a series-elastic element, and a parallel-elastic element. Tendon was assumed to be elastic. The response of the model to anterior-posterior drawer suggests that the geometrical and mechanical properties of the model ligaments approximate the behavior of real ligaments in the intact knee. Calculations for a simulated quadriceps leg raise indicate further that the two-dimensional model reproduces the response of the three-dimensional knee under similar conditions of loading and constraint. During maximum isometric contractions of the quadriceps, the model ACL is loaded from full extension to 80 degrees C of flexion; the model PCL is loaded at 70 degrees of flexion and greater. For maximum isometric extension, ACL forces in the range 0-20 degrees of flexion depend most heavily upon the force-length properties of the quadriceps. At flexion angles greater than 20 degrees, cruciate ligament forces are determined by the geometry of the articulating surfaces of the bones. During isolated contractions of the hamstrings and gastrocnemius muscles, the model ACL is loaded from full extension to 10 degrees of flexion; the model PCL is loaded at all flexion angles greater than 10 degrees. Isolated contractions of the flexor muscles cannot unload the ACL near full extension, as the behavior of the ACL in this region is governed by the shapes of the bones. At 10 degrees of flexion or greater, the overall pattern of PCL force is explained by the force length properties of the hamstrings and by the geometrical arrangement of the flexor muscles about the knee.

Adult↗
PubMed2006

[One-stage reconstruction of the two cruciate ligaments with a single autogenous graft from the extensor system: techniques and results of 25 chronic cases].

PURPOSE OF THE STUDY: Chronic tears of both cruciate ligaments are rarely encountered. Management practices have varied. One-stage reconstruction of both ligaments using arthroscopically implanted allografts was proposed starting in 1996 for such chronic laxity but only 44 cases have been reported in six papers mixed in with recent cases raising very different problems. Treatments using allografts or autogenous grafts or both implanted arthroscopically have often been combined with open surgery. We report a retrospective analysis of 25 knees treated with the same technique from 1983 to 2004: reconstruction with a single transplant taken from the extensor system. MATERIAL AND METHODS: A 30-cm lenght patella tendon-patella-quadriceps tendon graft was harvested. The patellar block was fixed in a hole drilled under the tibial spine, the patellar tendon replacing the posterior cruciate ligament and the quadriceps tendon passing through the lateral condyle and replacing the anterior cruciate ligament before implantation on Gerdy's tubercle, this also creating an extra-articular plasty with the same implant. Medial, lateral and posterior plasties were performed, depending on the radiographic assessment of laxity. Twenty-five knees with major laxity and instability were operated on, including 14 in two-stage operations. The differential anterior drawer was 10+/-3 mm medially and 9+/-5 mm laterally. The posterior drawer at 70 degrees was 15+/-4 mm medially and 10+/-6 degrees laterally. The total anteroposterior laxity of the medial compartment was 29 mm, it was 30 mm for the lateral compartment. Lateral laxity was considered major (>10 degrees ) in 17 knees and medial laxity in 7. Lateral and medial laxities were associated in eleven knees. Hyper-extension was very severe in five knees. RESULTS: Functional outcome at mean 6.5 years follow-up (range 1-21) was satisfactory (except in three knees) allowing renewed occupational activity. Resumption of sports activity was less marked and none of the knees was in IKDC class A, corroborating results in the literature. Anatomic outcome was assessed on the radiological drawer decrease which was modest, mean gain in the anterior drawer measuring 4 and 5 mm in the medial and lateral compartments and mean gain in the posterior drawer measuring 5 mm medially and 3 mm laterally. Peripheral laxity was corrected for best. DISCUSSION: Classically, one or other of the cruciate ligaments is repaired, sometimes both, but in a two-stage procedure associating two different methods and autogenous tendon grafts. One-stage reconstruction of both cruciate ligaments with a single autogenous graft and a wide approach has not led to any complications. One-stage reconstruction using this technique has several advantages: one anterior incision, single transplant which also enables lateral plasty, short immobilization time with rapid rehabilitation.

Adolescent↗
PubMedDate not supplied

The treatment of acute combined ruptures of the anterior cruciate and medial ligaments of the knee.

We performed a prospective study of 46 patients with ruptures of the anterior cruciate ligament and medial ligamentous structures. All patients had anterior cruciate ligament allograft reconstructions. Group I comprised 34 patients in whom all of the medial structures were ruptured (parallel and oblique fibers of the superficial medial collateral ligament and the posteromedial capsule) and were treated operatively. In Group II (12 patients), the superficial medial ligament fibers only were ruptured and these were treated nonoperatively. All patients started an immediate motion and rehabilitation program. Forty-four patients returned for followup at a mean of 5.3 years (range, 2 to 8.9) postoperatively. The results were assessed using the Cincinnati Knee Rating System. At followup, 20 knees (59%) in Group I and 9 knees (73%) in Group II had less than 3 mm of increased displacement on KT-1000 arthrometer testing (134 N). The overall rate of anterior cruciate ligament graft failure was 15%: six (18%) in Group I and one (8%) in Group II. No patient had more than 2 mm of increase on valgus stress testing at 5 degrees or 25 degrees of knee flexion. The overall ratings were as follows: Group I, 20 knees (58%) excellent or good and 14 knees (42%) fair or poor; and Group II, 11 knees (91%) excellent or good and one knee (9%) fair. Knee motion complications and patellofemoral symptoms were common in the patients rated fair or poor in Group I.

Adolescent↗
PubMedDate not supplied

Primary repair for posterior cruciate ligament injuries. An eight-year followup of fifty-three patients.

We reviewed 53 of 58 patients who had primary repairs of posterior cruciate ligament injuries between 1981 and 1988. Sixteen patients had isolated posterior cruciate ligament ruptures, 16 had complex injuries with capsular and collateral ligament involvement, and 21 had additional anterior cruciate ligament ruptures. Forty-six patients were treated by transosseous multiple-loop sutures and seven with bony avulsions by screw osteosynthesis. The mean follow-up time was 7.5 years (range, 3 to 12). All patients were examined subjectively (questionnaire) and objectively (clinical examination, KT-1000 arthrometer, functional testing, radiographs, and Cybex II isokinetic strength analysis). The results were graded according to the International Knee Documentation Committee evaluation form and the Lysholm score. The average Lysholm score was 82.4 (range, 40 to 100). Thirty-eight patients returned to their preinjury activities at the same intensity level. The patients' subjective assessments were normal or nearly normal in 35 patients. The posterior drawer test was negative or 1+ in 46 patients. Cybex isokinetic strength analysis revealed a decrease in quadriceps muscle strength of the involved limb by 10.5% (P < 0.01). Our data suggest that primary repair of posterior cruciate ligament ruptures provides good results after 8 years in approximately two thirds of the patients. Distal ligamentous ruptures, lack of athletic activity, and temporary olecranization correlated with poor results. Bony avulsions, midsubstance or proximal ruptures, and athletic activity correlated with good results.

Adolescent↗
PubMed1993

[Ligaments of the knee].

The authors study the various ligaments of the knee and, for each one, the anatomy, mechanisms of injury, clinical diagnosis, indications for imaging (plain x-rays, arthroscopy, MRI). The anterior cruciate ligament and posterior cruciate ligament are best visualised by MRI. The tibial collateral ligament and fibular collateral ligament are also well visualised by MRI. The value of the posteromedial and posterolateral angle points, stabilising functional structures, is emphasised together with the important diagnostic distinction between isolated ligamentous lesions and associated lesions. MRI constitutes the best imaging technique for assessment of the lesions. It completes the clinical examination and should be performed early.

Anterior Cruciate Ligament↗
PubMed1999

Phrenoesophageal ligament re-visited.

The phrenoesophageal ligament, attaching the esophagus to the diaphragm, has been given little emphasis in anatomy teaching. This study was undertaken to examine the macroscopic and microscopic structure of the phrenoesophageal ligament. The results indicate that the ligament is a distinct structure bridging the space between the esophageal wall and the margins of the esophageal hiatus. This ligament appears to arise from both the endothoracic fascia and the transversalis fascia and is composed of abundant collagen and elastic lamellae. Toward the wall of the esophagus, the ligament divides into a prominent upper leaf and an ill-defined lower leaf before inserting into the wall of the esophagus. Histological study reveals that the ligament has a substantial and deep insertion into the wall of the esophagus. It appears that the ligament plays an important role in anchoring the lower esophagus and maintaining gastroesophageal competence.

Cadaver↗
PubMed1983

Cell density and cell generation in the periodontal ligament of mice.

The number of cell nuclei per mm2 and the volume density of cell nuclei and blood vessels in the periodontal ligament at different levels of the mesial root of the first mandibular molar of the adult mouse and in different areas of the ligament at each level have been examined in the light microscope. Significantly higher numbers of cell nuclei per mm2 were observed adjacent to bone, cementum, and blood vessels than in the avascular body of the ligament at all levels and on all aspects of the root. This distribution of number of cell nuclei per mm2 was constant over 4 1/2 months of aging and a doubling of body weight. The volume density of cell nuclei was significantly higher in cells adjacent to bone and cementum and in gingival connective tissue than in both the vicinity of blood vessels and the body of the ligament. The blood vessels, which were present predominantly in the bone-related half of the ligament, were absent from the zone immediately adjacent to cementum. The labeling indexes of periodontal ligament cells were determined from autoradiographs of the mesial root of the first mandibular molar of the mouse after pulse-labeling with 3H-Tdr. Labeling indexes were highest in zones adjacent to blood vessels, and the labeling index was significantly higher in the middle of the ligament than in zones adjacent to bone and cementum, and consequently was inversely related to cell density.

Animals↗
PubMed1977

The site of remodeling of collagen in the periodontal ligament of the mouse incisor.

In an attempt to localize the site of remodelling of collagen in the periodontal ligament of the continuously erupting mouse incisor a radioautographic and stereologic investigation was undertaken. Grain distributions in radioautographs for light microscopy were studied at various time intervals after administration of [3H]-proline. The distribution of rough endoplasmic reticulum cisternae in fibroblasts and the incidence of collagen phagocytosis across the ligament were studied by means of stereologic methods at the electron microscopic level. No significant differences were found in half lives of [3H]-labelled substances among the various regions across the ligament. Rough endoplasmic reticulum cisternae within fibroblasts were distributed more or less uniformly throughout the entire width of the ligament. Analysis of the distribution of collagen phagocytosis, however, revealed that in the midregion of the ligament the amount of phagocytosed collagen was approximately four times as high as in the area adjacent to the tooth and about nine times as high as in the alveolar compartment. It is concluded that synthesis and turnover of total protein occurs throughout the periodontal ligament but that remodelling of collagen predominantly takes place in an intermediate area of the ligament.

Animals↗
PubMed2005

Cruciate ligament laxity and femoral intercondylar notch narrowing in early-stage knee osteoarthritis.

OBJECTIVE: The influence of the cruciate ligaments in spontaneous osteoarthritis (OA) is not understood, although ligament rupture is known to cause secondary OA. Additionally, femoral notch narrowing at the anterior cruciate ligament (ACL) insertion site is associated with disease severity, but it is unknown whether ligament deterioration precedes or follows osteophyte formation. We examined cruciate ligament mechanics and metabolism and the intercondylar notch width in OA-prone Dunkin-Hartley (DH) guinea pigs at ages up to and including the age at OA onset (24 weeks), and compared the data with those in age-matched controls (Bristol strain 2 [BS2] guinea pigs). METHODS: Guinea pigs were assessed at 3, 6, 9, 12, 16, 20, 24, and 36 weeks of age. ACLs were mechanically tested, and the intercondylar notch width index (NWI) was determined. Cruciate ligament metabolism was determined by measuring the following markers of collagen turnover: matrix metalloproteinase 2 (MMP-2), tissue inhibitor of metalloproteinases 2, C-terminal type I procollagen propeptide (PICP), and the immature collagen-derived crosslink dihydroxylysinonorleucine (DHLNL). RESULTS: DH guinea pigs had significantly laxer ACLs than did BS2 guinea pigs, at 12, 16, and 24 weeks. We observed elevated levels of pro and active MMP-2, PICP, and DHLNL in the cruciate ligaments of DH animals at most ages, compared with BS2 guinea pigs. The NWI in DH animals was significantly lower than that in BS2 guinea pigs at 24 and 36 weeks. CONCLUSION: In DH guinea pigs, laxer ACLs, which are associated with increased collagen turnover, may cause joint instability and predispose these animals to the early onset of OA. Decreased intercondylar notch width in the DH animals indicates that bone remodeling at the ACL insertion site is a response to elevated ACL laxity.

Animals↗
PubMed1995

A new retinacular ligament and vein of the human temporomandibular joint.

In the human temporomandibular joints of 14 Japanese cadavers, we observed a new retinacular ligament that connected to the retrodiskal pad posterolaterally and was accompanied by a vein draining the retrodiskal pad. This retinacular ligament originated from lateral to posterolateral part of the joint. The origin included the articular tubercle of the zygomatic process of the temporal bone. The ligament descended along the mandibular ramus to insert into the fascia of the masseter muscle at the mandibular angle. The vein originated from the venous plexus in the retrodiskal pad and ran parallel to the retinacular ligament, giving off branches to the retromandibular, transverse facial, and superfacial temporal veins. There were no remarkable differences in the size of the retinacular ligaments among individuals as well as between the left and right sides. The retinacular ligament had firm fibrous connections with the posterolateral part of the retrodiskal pad, where the external fibrous membrane of the articular capsule was lacking. These findings suggest that the retinacular ligament and its accompanying vein function together to maintain blood circulation during jaw movement and may also be related to the development of occlusal disorders.

Adult↗
PubMed1985

Sensory innervation of periodontal ligament of rat molars consists of unencapsulated Ruffini-like mechanoreceptors and free nerve endings.

The trigeminal ganglion (TG) of adult rats was injected with 3H-amino acids to label periodontal receptors by axonal transport; 20-24 hours after injection, samples of molar ligament were prepared for autoradiography and electron microscopy. Four types of neurites labeled from TG were found in the avascular ligament fiber regions: large, complex, Ruffini-like endings, lacking a capsule, but with finger extensions touching ligament collagen; smaller Ruffini-like endings, lacking a capsule and neural fingers; free bundles of unmyelinated axons; and free, small, myelinated axons. The vascular channels plus associated loose connective tissue that perforate the ligament contained labeled preterminal ensheathed axons, small Ruffini endings, and free unmyelinated or small myelinated axons. The incidence of labeled endings was about 5 X greater next to the lower third of the root than in the upper two-thirds or beneath the root. The TG myelinated axons (diameter range 2-15 microns) entered the ligament in sheathed nerve bundles; these branched to form numerous small preterminal axons that were surrounded by a periaxonal fluid space and a perineurial sheath. Terminal axons branched from nodes of Ranvier, left the preterminal chamber, and followed an extended branching course through the collagen fibers. Large, complex Ruffini-like endings had numerous mitochondria and were partially covered by special lamellar Schwann cells and complex basal lamina; vesicles and multivesicular bodies were found near exposed regions of the receptor. Smaller Ruffini-like endings lacked neural fingers and had a simpler structure and less elaborate Schwann cells. The structure of Ruffini-like endings was highly varied; thus a structural continuum may exist from the largest, most complex to the smallest, simplest Ruffini-like receptor. The TG unmyelinated axons entered the ligament in ensheathed bundles; they then branched into free bundles that were found in the avascular ligament or near blood vessels. No encapsulated receptors were found.

Animals↗
PubMed2001

Sonography of the normal scapholunate ligament and scapholunate joint space.

PURPOSE: The aims of this study were to assess the visibility of the normal scapholunate ligament on sonography and to establish the normal scapholunate joint space width in the neutral position and radial and ulnar deviation. METHODS: Two hundred normal wrists in 100 subjects (55 men and 45 women; mean age, 40 years; range, 19-83 years) were examined with high-resolution sonography (5-12-MHz linear-array transducer). The visibility and thickness of the scapholunate ligament were recorded. The width of the scapholunate joint space, or interval, was measured in the neutral position and radial and ulnar deviation. The width of the distal radius was recorded as a comparative standard for the patients' body habitus. RESULTS: The dorsal scapholunate ligament was completely (100%) visible in 95 wrists (48%), partially (> or = 50%) visible in 60 (30%), barely (< 50%) visible in 15 (8%), and not visible in 30 (15%). The volar scapholunate ligament was completely visible in 13 wrists (7%), partially visible in 17 (9%), barely visible in 15 (8%), and not visible in 151 (76%). The proximal component of the ligament was not visible in any subject. Measurement of the scapholunate interval was limited by the lack of identifiable anatomic marks for reference. The mean width of the dorsal scapholunate interval was 4.2 mm (range, 2.3-6.3 mm) in the neutral position. The interval did not differ more than 2.5 mm between the left and right wrists. No predictable change in width on ulnar or radial deviation was evident. The mean scapholunate intervals and mean distal radial width were significantly wider in men than in women and on the right side than on the left side. CONCLUSIONS: The dorsal scapholunate ligament is completely or partially visible in 78% of normal wrists. Its detection following injury may help to exclude the possibility of scapholunate dissociation. There is a quite wide variation in scapholunate interval widths on sonography and an unpredictable response with stress testing. The absence of a visible scapholunate ligament on sonography does not indicate injury.

Adult↗
PubMed1986

Tensile properties of the medial collateral ligament as a function of age.

The biomechanical properties of the rabbit medial collateral ligament (MCL) as a function of maturation and age were investigated. Femur-MCL-tibia (F-M-T) preparations were obtained from rabbits of different age groups (open or closed epiphysis). Parallel increases in the animal body weight and ligament cross-sectional area were recorded with age. Cyclic and tensile failure tests were performed to obtain the structural properties of the F-M-T complex and the mechanical properties of the MCL substance. There were significant increases in the load at failure, energy-absorbing capability of the bone-ligament junction, and in the tensile strength of the ligament substance as a result of maturation and subsequent aging. Increases in the area of hysteresis obtained during cyclic loading-unloading were also documented. At the closing of the epiphysis, the mode of failure of the F-M-T structure progressed from tibial avulsion to failure in the midsubstance of the ligament. An asynchronous rate of maturation was observed between the structural properties of the bone-ligament complex and the mechanical properties of the ligament substance.

Aging↗
PubMed1990

The early effect of high molecular weight hyaluronan (hyaluronic acid) on anterior cruciate ligament healing: an experimental study in rabbits.

The purpose of this study was to assess, morphologically and biochemically, the effect of hyaluronan (HA) on the early repair process of the anterior cruciate ligament (ACL). Following partial bilateral laceration in the midsubstance of the cruciate ligament, a single dose of HA (MW of 3.6 x 10(6] was injected in one knee and saline in the contralateral knee. Postsurgery, the rabbits were allowed normal (nonimmobilized) cage activity, and were killed after 4 (n = 11) and 12 (n = 10) weeks. The ligaments were evaluated by gross morphology and graded according to the degree of repair. We used grades 1,2, and 3 for uncovered, partially covered, and totally covered lacerations, respectively. Five of the HA-treated ligaments at each time studied were completely covered, compared to 0 at 4 weeks, and 1 at 12 weeks in the saline group. Paired evaluations of the lacerated ACLs showed that the HA-treated ligaments received a healing grade higher than the ligaments exposed to saline in 14 of the 21 animals. In the remaining animals, there was no difference between the sides. The repaired tissue of the ACLs was also examined by light and electron microscopy. When compared qualitatively with saline controls, HA-treated ligaments exhibited a more pronounced repair, with an increased angiogenesis and less inflammatory response. Biochemical analysis demonstrated a mean higher value of type III collagen in the HA-treated injured ACL than in saline-treated injured ACL (13.4 +/- 1.1% and 11.0 +/- 0.8%, respectively). This increased synthesis of type III collagen in the HA-treated injured ACL was statistically higher (p less than 0.05) when compared to the saline-treated injured ACL.

Animals↗