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PubMedDate not supplied

The role of the lateral extraarticular restraints in the anterior cruciate ligament-deficient knee.

We measured the increases in tibiofemoral motion when lateral structures were sectioned in anterior cruciate ligament-deficient knees of 20 unembalmed cadaveric whole lower limbs. Motion was measured with a six degrees-of-freedom electrogoniometer. The lateral structures investigated were the iliotibial band and mid-lateral capsule, lateral collateral ligament, and popliteus tendon and the posterolateral capsule. Cutting the anterolateral structures increased anterior translation and internal rotation, particularly in flexion. Increases in motions were highly variable, reflecting the variation in function in the lateral collateral ligament and posterolateral structures. Cutting the lateral collateral ligament produced small changes in anterior translation and external rotation and larger increases in adduction. Cutting the posterolateral structures produced small increases in external rotation. Large increases in external rotation were found only if the lateral collateral ligament was also sectioned. The posterolateral structures act in concert with the lateral collateral ligament in restraining internal and external rotation. External rotation was affected at all flexion angles; internal rotation was affected mainly in extension. Our results can be used in the diagnosis of complex knee ligament injuries. Findings of increased anterior translation in both flexion and extension and increased internal rotation at 90 degrees of flexion are consistent with combined injury to the anterior cruciate ligament and the anterolateral structures. The anterior cruciate ligament-deficient knee with significant posterolateral compromise (posterolateral structures/lateral collateral ligament) would exhibit larger anterior translation in extension than in flexion, increased adduction, and increased external rotation in both flexion and extension.

Adult↗
PubMed1995

[Healing of ligaments and tendons].

Regeneration of ligaments and tendons is a slow process, compared with the healing of other connective tissues (e.g., bone). Healing starts from the surrounding soft tissues ("extrinsic healing"), but also from the ligament or tendon itself ("intrinsic healing"). Regeneration is poor when there is little surrounding soft tissue available, as is the case in the anterior cruciate ligament. Regeneration of the medial collateral ligament of the knee is examined best. Mechanical and ultrastructural properties are not completely normal even 1 year after dissection of the ligament irrespective of whether it was sutured or not. Our own experiments on rabbit anterior cruciate ligaments showed that there is no regeneration after complete transection of the ligament. After incomplete transection there is regeneration, but maximum load of the ligament reaches only about 3/4 of the values of the sham-operated contralateral side. An additional experiment showed that regeneration is significantly better with the application of continuous passive motion, and elongation of the ligament can be avoided. If the healing tissue is not loaded, regeneration results in unstructured scar tissue. Under functional load, the collagen fibers are oriented in a longitudinal direction and the mechanical properties are optimized. There are no fundamental differences in the healing process between tendons and ligaments.

Animals↗
PubMed1999

Anatomy of pelvic arteries adjacent to the sacrospinous ligament: importance of the coccygeal branch of the inferior gluteal artery.

OBJECTIVE: To describe the arterial vascular anatomy in the area of the sacrospinous ligament. METHODS: Cadaver pelvises were dissected to reveal the anatomy of the sacrospinous ligament with emphasis on vascular and neuroanatomy. Flexible rulers were used to measure the coccygeal branch in five hemipelvises. RESULTS: The pudendal vessels and nerve pass immediately medial and inferior to the ischial spine (within 0.5 cm of the spine) and behind the sacrospinous ligament. The pudendal artery lies anterior to the sacrotuberous ligament, which passes behind the ischial spine to its attachment at the posterior ischial tuberosity. The inferior gluteal artery originates from the posterior or the anterior branch of the internal iliac artery to pass behind the sciatic nerve and the sacrospinous ligament. There is a 3- to 5-mm window in which the inferior gluteal vessel is left uncovered above the top of the sacrospinous ligament and below the lower edge of the main body of the sciatic nerve plexus. The coccygeal branch of the inferior gluteal artery passes immediately behind the midportion of the sacrospinous ligament and pierces the sacrotuberous ligament in multiple sites. The main body of the inferior gluteal artery leaves the pelvis by passing posterior to the upper edge of the sacrospinous ligament and following the inferior portion of the sciatic nerve out of the greater sciatic foramen. CONCLUSION: Sutures placed through the sacrospinous ligament at least 2.5 cm from the ischial spine along the superior border of the sacrospinous ligament and without transgressing the entire thickness are in an area generally free of arterial vessels.

Arteries↗
PubMed2002

Modeling of failure mode in knee ligaments depending on the strain rate.

BACKGROUND: The failure mechanism of the knee ligament (bone-ligament-bone complex) at different strain rates is an important subject in the biomechanics of the knee. This study reviews and summarizes the literature describing ligament injury as a function of stain rate, which has been published during the last 30 years. METHODS: Three modes of injury are presented as a function of strain rate, and they are used to analyze the published cases. The number of avulsions is larger than that of ligament tearing in mode I. There is no significant difference between the number of avulsions and ligament tearing in mode II. Ligament tearing happens more frequently than avulsion in mode III. RESULTS: When the strain rate increases, the order of mode is mode I, II, III, I, and II. Analytical models of ligament behavior as a function of strain rate are also presented and used to provide an integrated framework for describing all of the failure regimes. In addition, this study showed the failure mechanisms with different specimens, ages, and strain rates. CONCLUSION: There have been several a numbers of studies of ligament failure under various conditions including widely varying strain rates. One issue in these studies is whether ligament failure occurs mid-ligament or at the bone attachment point, with assertions that this is a function of the strain rate. However, over the range of strain rates and other conditions reported, there has appeared to be discrepancies in the conclusions on the effect of strain rate. The analysis and model presented here provides a unifying assessment of the previous disparities, emphasizing the differential effect of strain rate on the relative strengths of the ligament and the attachment.

Journal Article↗
PubMed1995

Synergistic effect of growth factors on cell outgrowth from explants of rabbit anterior cruciate and medial collateral ligaments.

Cellular migration and proliferation are integral aspects of wound healing. An in vitro assay for cellular migration and proliferation using explants of rabbit anterior cruciate and medial collateral ligaments was developed previously. This study presents the effects of serum-free culture medium supplemented with basic fibroblast growth factor, bovine insulin, transforming growth factor-beta 1, and platelet-derived growth factor-B, added either individually or in combination, on cell outgrowth in explants of rabbit anterior cruciate and medial collateral ligaments. Outgrowth was assessed at 3 and 6 days by counting the number of cells surrounding the tissue explants. For explants of both ligaments, cell outgrowth was dependent on the presence of 10% fetal bovine serum or the combination of growth factors. Little outgrowth occurred in explants of either ligament in the presence of basic fibroblast growth factor, transforming growth factor-beta 1, or bovine insulin. Platelet-derived growth factor-B at concentrations of 20 and 100 ng/ml seemed to increase cell outgrowth from medial collateral ligament explants at 6 days. The outgrowth from the explants of both ligaments was much greater in the presence of all four growth factors than the sum of the outgrowth with the individual factors. This synergistic effect was as much as 10-fold and 20-fold for the anterior cruciate ligament explants at days 3 and 6, respectively, but no more than 3-fold for the medial collateral ligament explants at these times. Medial collateral ligament explants exhibited greater cell outgrowth than anterior cruciate ligament explants in 10% serum and in the presence of the four growth factors.

Animals↗
PubMed2003

Radiofrequency treatment weakens the fatigue characteristics of rabbit anterior cruciate ligament.

OBJECTIVE: To evaluate the radiofrequency treatment applied to an intact anterior cruciate ligament, and to quantify the mechanical effects of controlled cyclic loading (simulating activities of daily living) post-treatment. DESIGN: An in vitro radiofrequency energy application to the rabbit anterior cruciate ligament and cyclic loading of the treated ligament. BACKGROUND: Effect of cyclic loading on the radiofrequency treated ligament in a controlled environment is not known. METHODS: In the treatment group radiofrequency treatment was applied to an intact ligament and then the ligament was cyclically loaded for 3000 cycles, and stretched-to-failure. Control group was similar to treatment, except that the radiofrequency treatment was not applied. The cyclic loading (approximately 6% tensile strain) was kept below the injury threshold of the rabbit anterior cruciate ligament and was designed to simulate loading post-treatment. A relaxation test (5% constant strain for 180 s) was used to compare the results at different steps in the experiment; within each group and between the two groups. RESULTS: Relaxation force increased in the treatment group (average 108% of intact, P<0.05), but decreased after the cyclic loading (average 71% of intact, P<0.05). There were significant differences in the force-deformation-failure curves between the treatment and control groups: average treated ligament failed at 59% and 57% of the control values respectively for the deformation and force (P<0.05). CONCLUSIONS: Using radiofrequency treatment makes rabbit anterior cruciate ligament weaker following cyclic loading. RELEVANCE: The radiofrequency treatment weakens the anterior cruciate ligament, and therefore, it perhaps should be protected until healing and adaptation restore its full strength.

Activities of Daily Living↗
PubMed2004

Cervical spine ligament injury during simulated frontal impact.

STUDY DESIGN: The supraspinous and interspinous ligaments, ligamentum flavum, and capsular and posterior longitudinal ligament strains were monitored during simulated frontal impact of whole cervical spine specimens with muscle force replication and compared with corresponding physiologic strain limits. OBJECTIVES: To quantify the strains in the cervical spine ligaments during simulated frontal impact and investigate injury mechanisms. SUMMARY OF BACKGROUND DATA: Clinical and biomechanical studies have documented injuries to cervical spine ligaments during frontal impact. There are no biomechanical studies investigating subfailure injury mechanisms to these ligaments during simulated frontal impacts of increasing severity. METHODS: The whole cervical spine with muscle force replication model and a bench-top sled were used to simulate frontal impacts at 4, 6, 8, and 10 g horizontal accelerations of the T1 vertebra. The peak ligament strains during frontal impacts were compared with physiologic strain limits determined during intact flexibility testing. RESULTS: Significant increases (P < 0.05) in the supraspinous and interspinous ligaments and the ligamentum flavum strains beyond physiologic limits were observed throughout the cervical spine, with the highest strains occurring at C3-C4. Significant increases were observed in the capsular ligament strains only during the 10 g impact, whereas the posterior longitudinal ligament strains did not exceed physiologic limits. CONCLUSIONS: The supraspinous and interspinous ligaments and the ligamentum flavum may be at risk for injury due to excessive strains during frontal impacts.

Aged↗
PubMed2004

The accessory anteroinferior tibiofibular ligament as a cause of talar impingement: a cadaveric study.

BACKGROUND: A distal fascicle of the anteroinferior tibiofibular ligament has been reported as a possible cause of anterolateral ankle impingement. HYPOTHESIS: This fascicle represents an independent accessory ligament in the anterior aspect of the inferior tibiofibular syndesmosis. STUDY DESIGN: Descriptive anatomical study. METHODS: The inferior tibiofibular syndesmosis was exposed in 24 fresh-frozen cadaveric ankles. Morphological characteristics of the inferior tibiofibular ligaments and interactions between the anterior ligaments and the talus were investigated in different degrees of ankle motion. RESULTS: A separate accessory anterior ligament was identified in 22 specimens. Its orientation was parallel and distal to the anterior tibiofibular ligament, from which it was separated by a fibrofatty septum. Its length ranged from 17 to 22 mm, its thickness from 1 to 2 mm, and its width from 3 to 5 mm. Impingement of this ligament against the talar dome was documented in all specimens in neutral ankle position, with bending of the ligamentous bands in dorsiflexion. Distraction maneuvers reproducing traction during arthroscopic approaches relieved contact. CONCLUSIONS: An accessory anteroinferior tibiofibular ligament with distinct anatomical features was recognized. CLINICAL RELEVANCE: Based on its increased incidence in the cadaver ankles, the accessory ligament reflects a normal anatomical finding. Nevertheless, it could lead to anterolateral impingement in cases with coexistent ankle instability.

Ankle Joint↗
PubMedDate not supplied

Graft fixation in cruciate ligament reconstruction.

Cruciate ligament reconstruction has progressed dramatically in the last 20 years. Anatomic placement of ligament substitutes has fostered rehabilitation efforts that stress immediate and full range of motion, immediate weightbearing, neuromuscular strength and coordination, and early return to athletic competition (3 months). This has placed extreme importance on secure graft fixation at the time of ligament reconstruction. Current ligament substitutes require a bony or soft tissue component to be fixed within a bone tunnel or on the periosteum at a distance from the normal ligament attachment site. Fixation devices have progressed from metal to biodegradable and from far to near-normal native ligament attachment sites. Ideally, the biomechanical properties of the entire graft construct would approach those of the native ligament and facilitate biologic incorporation of the graft. Fixation should be done at the normal anatomic attachment site of the native ligament (aperture fixation) and, over time, allow the biologic return of the histologic transition zone from ligament to fibrocartilage, to calcified fibrocartilage, to bone. The purpose of this article is to review current fixation devices and techniques in cruciate ligament surgery.

Anterior Cruciate Ligament↗
PubMedDate not supplied

Anterior cruciate ligament rupture after thermal treatment in a canine model.

BACKGROUND: The use of radiofrequency energy to treat damaged anterior cruciate ligaments is gaining popularity. However, complete rupture of the ligament after treatment has been reported. PURPOSE: To evaluate the effect of thermal energy applied arthroscopically to normal, intact anterior cruciate ligaments in mature dogs. STUDY DESIGN: Controlled laboratory study. METHODS: Monopolar radiofrequency energy was applied to the normal anterior cruciate ligament of 1 knee in 18 dogs. The contralateral anterior cruciate ligament (also normal) was sham treated. Force-plate gait analysis was performed preoperatively and at 4, 8, 12, 16, 26, and 36 weeks after surgery. Anterior cruciate ligament rupture was detected by a sudden onset of nonweightbearing and a positive drawer sign. RESULTS: All treated ligaments ruptured approximately 55 days after surgery (mean, 55 days; standard error, 1.6). CONCLUSIONS: Although monopolar radiofrequency energy may have some potential in the treatment of lax anterior cruciate ligaments, in the application described here the result was a highly predictable deterioration and rupture of all treated anterior cruciate ligaments. CLINICAL RELEVANCE: On the basis of these findings, we strongly recommend that strict selection and application criteria be used when considering use of this modality on anterior cruciate ligaments that are stretched or partially disrupted, or both. Use of this modality should be followed by adherence to a highly conservative rehabilitation protocol.

Analysis of Variance↗
PubMedDate not supplied

Simulated lateral ankle ligamentous injury. Change in ankle stability.

The effect of simulated ankle ligamentous injury on ankle-subtalar joint complex laxity was studied. Thirty-six intact ankles were loaded in inversion-eversion and anterior-posterior directions. Motions of the talus and calcaneus were measured with respect to the tibia. Ankles were tested at neutral, 15 degrees of dorsiflexion, and 15 degrees of plantar flexion. In all the specimens the anterior talofibular ligament was sectioned and then the calcaneofibular ligament was sectioned; testing was then repeated. With sectioning of the anterior talofibular ligament, motion increased primarily in dorsiflexion with both anterior-posterior and inversion-eversion loading. This increase was primarily caused by a large increase in subtalar motion. Additional sectioning of the calcaneofibular ligament produced little change in ankle subtalar joint motion except in dorsiflexion. Clinically, these findings show that if an anterior-posterior drawer test shows less laxity in dorsiflexion than in neutral and greater laxity than the contralateral asymptomatic side, then an isolated anterior talofibular ligamentous tear exists. Similarly, laxity in 15 degrees of dorsiflexion and in neutral suggests calcaneofibular ligament disruption. During inversion-eversion loading, the increase in ankle-subtalar joint complex rotation with calcaneofibular ligament sectioning occurred primarily in the ankle joint, implying that the calcaneofibular ligament constrains the talus through the calcaneus. Therefore, a talar tilt on stress radiographs demonstrates a torn calcaneofibular ligament.

Ankle Injuries↗
PubMedDate not supplied

Biomechanical comparison of reconstruction techniques in simulated lateral ankle ligament injury.

Eighteen intact ankles were loaded with inversion-eversion and anterior-posterior forces, and motions of the talus and calcaneus were measured. Ankles were tested in neutral, 15 degrees of dorsiflexion, and 15 degrees of plantar flexion. The anterior talofibular ligament was then sectioned and testing was repeated. In half the specimens the calcaneofibular ligament was also sectioned followed by repeat testing. The Evans, Watson-Jones, and Chrisman-Snook procedures were performed on each ankle and testing was repeated. With inversion-eversion loading, only the Chrisman-Snook reconstruction resulted in a significantly more stable ankle joint complex than in the anterior talofibular ligament cut ankles. All three reconstructions increased ankle stability over the anterior talofibular and calcaneofibular ligament cut state. With anterior-posterior loading, all reconstructions resulted in a significantly more stable ankle joint complex than the anterior talofibular ligament cut ankles. The Evans and Chrisman-Snook procedures resulted in more stability than the anterior talofibular and calcaneofibular ligament cut ankles. There was no difference in subtalar joint motion with inversion-eversion loading among ankles with the anterior talofibular ligament cut and those with any of the reconstructions. For the anterior talofibular and calcaneofibular ligament cut ankles, subtalar joint motion was similar to that in intact ankles after each reconstruction. All three reconstructions resulted in ankles with significantly less subtalar joint motion with anterior-posterior loading than ankles with the anterior talofibular ligament cut or with the anterior talofibular and calcaneofibular ligaments cut. The Chrisman-Snook procedure resulted in ankles with significantly less motion than intact ankles.

Analysis of Variance↗
PubMed2006

Dysplasia of the cruciate ligaments: radiographic assessment and classification.

BACKGROUND: A common pathologic finding in the knee associated with congenital longitudinal deformity is aplasia of one or both cruciate ligaments. We performed a radiographic analysis to assess the changes in the femoral intercondylar notch and the tibial eminence in relation to the status of the cruciate ligaments. METHODS: Thirty-four knees in thirty-one patients with longitudinal congenital deficiency of the lower limb were evaluated. The cruciate ligaments and the associated abnormalities of the distal aspect of the femur and the proximal aspect of the tibia were evaluated with use of magnetic resonance imaging and a tunnel view radiograph. RESULTS: We differentiated three main types of dysplasia of the cruciate ligaments with typical associated changes. In type I, partial closure of the femoral intercondylar notch and hypoplasia of the tibial eminence are observed and the anterior cruciate ligament is hypoplastic or aplastic. In type II, these findings are accentuated and there is additional hypoplasia of the posterior cruciate ligament. In type III, the femoral intercondylar notch and the tibial eminence are completely absent and there is aplasia of both cruciate ligaments. CONCLUSIONS: We delineated three types of congenital deficiency of the cruciate ligaments and found corresponding morphologic changes of the femoral notch and the tibial eminence, which can be observed on tunnel view radiographs. Thus, the diagnosis and differentiation between aplasia of one or both cruciate ligaments and between congenital and trauma-induced absence of the cruciate ligaments may be made by interpreting plain radiographs.

Adolescent↗
PubMed2005

Alpha-smooth muscle actin expression in intact and ruptured human anterior cruciate ligament--an immunohistochemical assessment.

The objective of this work was to evaluate the distribution of alpha-smooth muscle actin cells in the intact human anterior cruciate ligament and to determine if rupture of the anterior cruciate ligament and the time since injury has any influence on the occurrence of cells with contractile capability, positively stained for a-smooth muscle actin. The intact anterior cruciate ligament group (group A) undergoing total knee arthroplasty, consisted of 9 patients (8 females) with mean age of 65.3 years. The anterior cruciate ligament rupture group (group B) consisted of 20 patients (18 males, 2 females) with mean age of 27.8 years. Healing time of the torn ligament in vivo lasted from 1 to 40 months and the patients were divided into 3 groups (Bi-Biii) embracing diverse time periods. All harvested anterior cruciate ligaments were sectioned in thirds so that there was a proximal, middle and distal third for each ligament. Distribution of alpha-smooth muscle actin was detected with mouse monoclonal anti-human smooth muscle actin antibody. The alpha-SMA cells density was significantly affected by the time after injury as well as the location in the ligament remnant. The decrease of alpha-smooth muscle actin cells in the proximal and middle thirds of the ligament after rupture may suggest that alpha-SMA cells are not mainly responsible for primary retraction of the ruptured human anterior cruciate ligament.

Actins↗
PubMed1995

[Trauma of the ligaments and tendons. Examination technique and detection in MRI].

For stress radiography, the inversion stress test can be performed during radiographic examination and widening of the lateral joint space can be measured quite accurately. However, there is no general agreement on the meaning of various degrees of talar tilt. Today MRI allows evaluation of the integrity of injured ankle ligaments. The major difficulty in MRI is inconsistency in visualization by inadequate appreciation of the three-dimensional orientation of each ankle ligament. The appropriate combination of foot position and imaging plane is very important to achieve the best visualization of each ligament. Using this technique, 52 patients with sprained ankles underwent MRI. The integrity of rupture of the collateral lateral ligaments was obtained in all 52 ankles. Full-length visualization is essential for evaluation of the ankle ligaments with MRI. In these 52 patients the ankle of tilt on the stress X-ray was compared with the rate of MRI findings showing an injury affecting two ligaments We found that none of the patients in whom the angle of lateral tilt was less than 5 degrees had rupture of two lateral ligaments, while 32% of patients with angles of tilt of 6-14 degrees and 42% of those with angles of tilt over 15 degrees on stress X-ray had two ruptured lateral ligaments. When a stress X-ray with a 6-14 degrees angle of tilt suggests only slight ligamentous injury, MRI could be indicated in specific cases to allow identification of the 32% with rupture of two ligaments. The only practical means of imaging tendons is high-frequency ultrasound and MRI.(ABSTRACT TRUNCATED AT 250 WORDS)

Achilles Tendon↗
PubMed1998

[Computerized tomography assessment of replacement of the cruciate ligaments of the knee].

January, 1993, to December, 1995, we examined with CT 44 patients submitted to surgical replacement of knee cruciate ligaments, namely 18 anterior cruciate ligaments (ACL) and 6 posterior cruciate ligaments (PCL). ACL was replaced with a patellar tendon graft (Eriksson technique) in 23 cases and with a semitendinous graft (Lindemann-Bousquet technique) in 7 cases. The autologous new ligament appeared as a laminar structure of intermediate density. The tendon had been covered with a synthetic lining (Leeds-Kejo) in 10 of the above cases, while the new ACL graft was completely synthetic in 8 cases, which synthetic allografts appeared hyperdense relative to autologous new ligaments. PCL replacement had been performed with Augustine technique (patellar tendon graft in a tibial tunnel) in 3 cases, with Hughston technique (medial gastrocnemius graft in a medial condylar tunnel) in 2 cases and with a synthetic graft (Gore-tex) in 1 case. Twelve of 38 new ACLs were injured (7 Eriksson, 3 Lindemann-Bousquet and 2 synthetic grafts): the injured new ligament was enlarged and hypodense, or involved in atrophic absorption. The new ligament was partially calcified in one of the 3 patients with PCL replacement with a patellar tendon graft (Augustine technique). The bone bract was dislocated in the intercondylar notch in a patient submitted to Hughston surgery because of proximal disinsertion of the new ligament. The Gore-tex new PCL was sinuous in the proximal tract, with intra-articular calcified loose bodies. CT adequately depicted surgical results and diagnosed the new ligament injuries and other articular abnormalities. MRI is currently the gold standard in the multiplanar studies of the postoperative knee, but CT can be confidently used to identify ligament injuries and intra-articular calcified loose bodies.

Anterior Cruciate Ligament↗
PubMed1996

Development of the human wrist joint ligaments.

BACKGROUND: Many studies have been published on the development of the human wrist joint, but scant attention has been given to the development of the wrist joint ligaments. Moreover, traditional description of wrist anatomy usually depict only the superficial capsular fibers of the wrist joint. The only ligamentous structure to receive much attention is the articular disc of the wrist joint, which has been described as a fibrocartilaginous structure extending from the medial edge of the lower end of the radius to the ulnar styloid process. METHODS: In the present report, we synthesize our observations in the wrist joint ligaments in 35 serially sectioned human embryonic and fetal hands (16 embryos and 19 fetuses). RESULTS: The interosseous intercarpal ligaments are organized from the mesenchyme, which, until O'Rahilly's stage 23, fills the intercarpal spaces. These ligaments are not individually distinguishable until the 9th week of development. The collateral ligaments begin to form in O'Rahillys's stage 22 and are completely formed by the end of week 10. The palmar radiocarpal and ulnocarpal ligaments (beginning with the palmar radiocarpal ligament) begin to form in O'Rahilly's stage 23 and are fully developed by the end of week 10. At this time, development of the dorsal radiocarpal ligament begins; this process is completed by the end of week 13. The articular disc which is initially formed of a single element, first appears in O'Rahilly's stage 23 and its organization is completed at week 10 of development. CONCLUSIONS: We establish the morphogenetic time-table of the wrist joint ligaments. Our descriptive findings may help explain carpal motion and the origin of wrist injuries.

Carpal Bones↗
PubMed1997

Morphological and immunohistochemical examination of nerves in normal and injured collateral ligaments of rat, rabbit, and human knee joints.

BACKGROUND: Knee joints possess an abundant nerve supply that relays sensory and motor information on such aspects as proprioception, nociception, and vasoregulation. Although synovial innervation has been well documented, little is known of the nerves that supply the collateral ligaments. METHODS: The morphology of rabbit and human collateral ligament nerves was examined by silver impregnation. Immunohistochemistry was performed on rabbit and rat collateral ligaments to determine the presence of peptidergic nerves in these tissues. A 6-week gap injury was performed on three rabbit medial collateral ligaments, and the localisation of peptidergic nerves in these tissues was determined. RESULTS: Irrespective of species or type of ligament examined, the greatest density of nerve fibres was found in the epiligament. Nerve fibres commonly accompanied blood vessels along the long axis of the ligament and then entered the substance of the tissue before ramifying in the deeper layers. Substance P and calcitonin gene-related peptide-immunoreactive nerve fibres were found in the collateral ligaments of the rat and rabbit. Injured ligaments showed a higher than normal level of immunoreactivity in and around the healing zone; however, the nerve fibres appeared tangled and truncated. CONCLUSIONS: Like other structures in knee joints, collateral ligaments possess a complex nerve supply. The presence of peptidergic nerves suggests that ligaments may be susceptible to neurogenic inflammation and may be centres of articular nociception.

Aged↗