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Lunate and perilunate dislocation.

BACKGROUND: Perilunate dislocation is an uncommon injury of the wrist due to hyperextension. The factors affecting its prognosis are still controversial. The aim of the present study was to review its fracture types, associated injuries, timing of surgery, different fixation methods and prognostic factors. METHODS: Fourteen patients with perilunate dislocation or fracture dislocation were treated by open reduction and internal fixation, and were followed for at least 12 months. A functional scoring system and X-ray findings were used for follow-up evaluation. RESULTS: Two patients had excellent results, six patients had good results, and four had fair results. Only two patients had poor results. Treatment delayed over one month, transscaphoid perilunar fracture dislocation, or fixation of the transscaphoid fracture with Kirschner wire was associated with poorer results. CONCLUSIONS: Early diagnosis of perilunate dislocation, prompt open reduction and rigid fixation for fracture combined with ligament repair can give more promising results.

Accidents, Traffic↗

Fractures and dislocations involving the navicular-lunate axis.

This is a report of experience with 48 carpal disruptions including anterior dislocations of the lunate, transnavicular perilunate and perilunate dislocations and subluxation of the navicular. The correct radiographic diagnosis is absolutely essential for effective treatment. Many of these injuries may be treated by closed reduction, but open reduction of transnavicular perilunate dislocations is the procedure of choice. Avascular necrosis of the lunate may follow open dislocation. Primary subluxation of the navicular may occur without dislocation of the lunate.

Carpal Bones↗

[Osteochondral fractures of the external femoral condyle after traumatic patellar dislocation during physical exercise in children].

PURPOSE OF THE STUDY: Nineteen osteochondral fractures of the lateral femoral condyle associated with acute traumatic patellar dislocation resulting from sport injury in children were studied. The purpose of this study was to specify clinical and radiological features. MATERIAL AND METHOD: This study was led with special care to injury circumstances, fracture visibility on X-rays, size and location of the fracture, treatment delay, presence of femoro-patellar dysplasia signs. Treatment results were evaluated on knee pain, bone consolidation and recurrent dislocation. RESULT: Thirteen boys and six girls aged 8 to 16 years (average 14 years) were included. The injury resulted from a rotatory-compression stress in 75 per cent cases. The patella was always in place at the time of examination. Thirteen fractures were diagnosed within 24 hours and 5 fractures were diagnosed within 1 week after injury. One fracture was not visible on X-rays and was diagnosed 6 weeks after injury. Only the lateral view showed the fracture in more than one case out of two. Seven patients whose fracture was less than 5 mm, or involving a non-weight-bearing portion, or diagnosed within more than ten days after injury, were treated by knee arthroscopy and removal of the osteochondral fragment. Twelve patients were treated by arthrotomy and excision (one case) or replacement of the osteochondral fragment (11 cases). The replaced fracture was fixed with biological glue ten times, and screwed once. The knee was immobilised in a cylinder cast and weight-bearing prohibited for six weeks. Bone consolidation was obtained in 9 cases out of 11, in an average of 8 weeks. Knee pain occurred 5 times. Recurrence of the dislocation occurred 3 times within 6 months. Eighty per cent of these children showed patello-femoral dysplasia. DISCUSSION: This fracture complicated 31.6 per cent of traumatic patellar dislocation resulting from sport injury in children which we observed during the last ten years. It may be overlooked if it is suspected and carefully looked for by radiographic examination including antero-posterior, lateral, oblique and true skyline views of the patella. The presence of fat in the hemarthrosis may help. Early surgery is recommended. Arthroscopy may be performed to evaluate fracture location and size. After ten days, host area begins to fill in and free fragment will not fit back well. Fragments less than 5 mm, or involving a non-weight-bearing portion, or diagnosed within more than ten days after injury, may be removed. CONCLUSION: Lateral femoral condyle osteochondral fractures are associated with nearly one third of traumatic patellar dislocation resulting from sport injury in children. A detailed radiographic examination can help diagnosis. Treatment depends on the delay after injury, the size and location of the fracture.

Adolescent↗

[Treatment of acromio-clavicular dislocations using coracoacromial ligament plasty].

PURPOSE: Plasty transfer using the coracoacromial ligament (Cadenat) for the treatment of acromioclavicular separation is usually too weak and too short. The authors used a reinforcement flap, made by a lateral supraclavicular detachment of the superior fibrous-capsular sheath. MATERIAL AND METHOD: Twenty-six acromioclavicular separations were radiographically studied using an axillary view. Twenty-one patients had a posterior dislocation of the lateral end of the clavicle. A pouch formed by the superior detachment was present in all cases with posterior displacement. In 19 case out of 26, this detachment was used to create a quadrangular flap with acromial support. The end of the coracoacromial ligament was attached to this long flap which provided adequate reinforcement along its entire length. RESULTS: There was a statistical correlation (p = 0.05) between the posterior component of the separation and the presence of this detachment. In the 19 reinforced plasties, no recurrence of posterior dislocation was reported, a mild undercorrection and 2 overcorrections were noted. Recurrent posterior dislocation was reported in the 7 non-reinforced coracoacromial plasties, and superior dislocation was reported twice. DISCUSSION: Posterior acromioclavicular dislocation is present in 80 per cent of cases. Diagnosis mainly uses the axillary view. It is always associated with a lateral supraclavicular detachment providing a 3 to 5 cm long downward flap which is used as a natural reinforcement for the coracoacromial ligamentoplasty.

Acromioclavicular Joint↗

[Plantar dislocation of the tarso-metatarsal articulation (Lisfranc articulation). Apropos of a case].

Plantar fracture-dislocation of the tarso-metatarsal joint (Lisfranc plantar fracture-dislocation) is rather unusual. The authors described a case sustained in a 39 years old man injured in a motorcycle road traffic accident. Mechanism was recognized as plantar hyperflexion combined with an axial foot compression. Open reduction, and K-wires fixation were performed. An anatomical feature was restored. In an additional anatomical study on 8 cadavers, the plantar direction of a fracture-dislocation of the tarso-metatarsal joint was observed when the injury axis followed the scapho-cuneiform joint of the inner border of the foot and the cuboïdo-metatarsal joint on the lateral border, so that both tibialis muscles were fixed on the distal fragment. As tibialis posterior muscle is more powerful, the direction of the dislocation will be plantar. This type of injury is different from plantar fracture-dislocation of the tarso-metatarsal joint secondary to direct load bearing on the dorsum of the foot with severe skin and vessels injuries.

Accidents, Traffic↗

Popliteal artery thrombosis associated with trampoline injuries and anterior knee dislocations in children.

Recent reports have emphasized the benign nature of trampoline-associated injuries. However, this study describes the limb-threatening problem of popliteal artery thrombosis occurring in association with anterior knee dislocation and trampoline injuries. Three children (ages 11, 13, and 17) were referred to the emergency room within the past 12 months with anterior dislocations of the knee, which occurred while jumping on trampolines. All patients had reduction of their dislocations at outside facilities and were referred within 6 to 12 hours after their injuries, with pulse, motor, and sensory deficits. All patients were taken directly to the operating room, where arteriography confirmed thrombosis of the popliteal artery below the knee. One patient had transection of the artery, whereas two patients had stretch injuries with intimal separation. Each patient required interposition grafting with reversed saphenous vein and underwent concomitant four-compartment fasciotomy. All patients had persistent sensory and motor deficits postoperatively, which were presumed to be a combination of ischemic injury and neuropraxia. All patients have functioning grafts with an average follow-up of 1 year (range, 9-15 months). One patient required a second interposition graft to treat an area of intimal hyperplasia, which developed at the proximal anastomosis, at 6 months postoperatively. Eighty per cent of trampoline injuries are associated with minor injuries with minimal long-term complications. However, dislocations of the knee may be associated with significant arterial injury and amputation rates of up to 30 per cent in many blunt trauma series. Based on our experience, physicians should recognize the possibility of significant arterial injuries occurring in children with anterior knee dislocations while jumping on trampolines.

Adolescent↗

[Reconstruction of cervical stability following old facet dislocation of cervical spine].

A total of 12 cases of old facet dislocations of cervical spine treated between december 1988 and 1993 were analyzed in order to evaluate the efficacy of various surgical modalities. In this series, there were 8 males and 4 females, with ages ranged from 16 to 50 years old (averaged 37.8 years old). The duration from injury to admission to our hospital was ranged from 1 to 8 months (averaged 3.7 months). Dislocation levels were as follows: C3,4 in 1 case, C4,5 in 4 cases, C5,6 in 4 cases and C6,7 in 3 cases. Unilateral facet dislocation was in 7 cases and bilateral facet dislocation in 5 cases. Neurological status on admission was as follows: spinal cord and nerve root lesion in 5 cases, nerve root lesion alone in 5 cases and neurologically intact in 2 cases. Besides all facets receiving facetectomy and iliac bone graft, other four kinds of adjuvant treatments were used, including internal fixation by stainless wires laminae or spinous processes in 4 cases, Luque rod in 1 cases, anterior fibrolysis combined with posterior laminoplasty in 1 cases and sustained skull traction without internal fixation in 6 cases. The reduction efficacy from postoperative stustained skull traction was better and the stainless wires fixation ranked the next. The patients only suffering from the nerve root lesion recovered better, but those who had spinal cord combined with nerve root lesion recovered badly. In conclusion, for the treatment of old facet dislocation, it is necessary to resect the facet and graft with iliac bone.

Adolescent↗

Dislocation and instability complicating low friction arthroplasty of the hip joint.

Among the complications in a series of 1,400 consecutive Charnley low friction arthroplasty procedures, there were 8 dislocations, and 3 highly unstable hips. Three dislocations followed severe trauma, in 2 of the 3 there was only fibrous union of the greater trochanter. In all but 2 of the hips, more than one previous operation had been performed. More than one technical fault was evident in most dislocations. Six of the 8 dislocations required reoperation. Meticulous attention to the Charnley procedure, including soft tissue elements of the hip joint is necessary to avoid instability and dislocation following total hip arthroplasty.

Adult↗

Lung lamellar body amphiphilic topography: a morphological evaluation using the continuum theory of liquid crystals: II. Disclinations, edge dislocations, and irregular defects.

The bilayers in normal mammalian and human lung multilamellar bodies (LMB) are parallel, equally spaced, and continuous--a configuration that minimizes the large elastic strain energy associated with changing the equilibrium bilayer separation and the hydrophobic-hydrophilic repulsion energy between the hydrocarbon tails of phospholipid and the aqueous phase. This ideal behavior is disrupted at a limited population of large Burgers vector edge dislocations dissociated into +/- 1/2 disclination pairs. The configuration and interaction of the defects are explained by the continuum theory of liquid crystals and are shown to be identical to defects observed in in vitro surfactant liposomes and bilayers. We report the first observations with molecular resolution of the core structure of a liquid crystal dislocation. Defect cores are shown to be located between both headgroups and tailgroups in human LMB, suggesting that both types of core are similar in energy. This may be the result of partitioning of proteins or other nonlipid impurities in the LMB to the defect cores, which might also change the stability of the dislocations to favor their preservation. The edge dislocation defects interact in ways that minimize their overall strain energy. A population of edge dislocations may play an important role in the transport or localization of certain molecules through the lamellar body. Certain defects were observed in lung multilamellar bodies that have not been observed in in vitro systems; these are probably due to the complex, multicomponent nature of the LMB surfactant and the dynamic, in vivo environment of the LMB.

Animals↗

On the electrical properties of dislocations in ZnS using electric force microscopy.

A combination of electric force microscopy (EFM) and noncontact atomic force microscopy (AFM) was used to study microscratching-induced dislocations in sphaleritic ZnS single crystals. Dislocation bands predominantly consisting of either anion-type (S) or cation-type (Zn) dislocations were induced by scratching along either [111] or [111] on a (110) surface. A significant difference of local distortions in electrical potential between the S(g) and Zn(g) dislocation bands was observed from the EFM images. Electric charges of these dislocations were determined quantitatively and the results were compared with theoretical models.

Journal Article↗

Cervical dislocation of mice induces rapid accumulation of platelet serotonin in the lung.

As much as 3-8 micrograms/g wet weight of serotonin (5-hydroxytryptamine, 5HT) has been detected in mouse lung 10 sec after the animal was sacrificed by cervical dislocation. Perfusion of the lung was carried out to determine where the majority of 5HT was located. Of the total 5HT, 84.3% was measured in the perfusate in which 90-98% was recovered in the platelet-rich fraction. When lungs were dissected from mice without cervical dislocation, either after instantaneous killing by irradiation with high power microwaves or under anesthesia, 5HT in the lung was 0.40-1.60 microgram/g tissue. These results show that cervical dislocation induces the entrapment of platelets in the pulmonary capillaries within 10 sec. The pulmonary accumulation of 5HT induced by cervical dislocation was approximately 50% inhibited by both prazosin and yohimbine, suggesting that the alpha-adrenergic receptor plays some part in the process. Norepinephrine but not isoproterenol augmented by 180% the response of pulmonary 5HT to cervical dislocation.

Animals↗

[Late dislocation of a plate haptic silicone lens into the vitreous body after Nd:YAG capsulotomy. A case report].

UNLABELLED: We describe a case that was referred 10 months after Nd:YAG laser treatment with a posteriorly dislocated silicone intraocular lens (IOL) into the vitreous cavity. PATIENT: A 70-year old white woman underwent uncomplicated phacoemulsification with in-the-bag placement of a Chiron silicone plate haptic lens through a 5.5- mm continuous circular capsulorhexis. The patient was fine until 9 months postoperatively when she complained of a decrease in visual acuity due to capsular fibrosis. A successful Nd:YAG laser capsulotomy was performed, resulting in an increase in visual acuity. Ten months later, the patient noted acute and atraumatic loss of vision, and the IOL was found to have dislocated posteriorly onto the retina. RESULTS: The dislocated IOL was removed via the anterior chamber following pars plana vitrectomy. Perfluorocarbon liquid was used to elevate the slippery lens from the retinal surface. The IOL was removed by a Sato Knife from the anterior chamber, followed by implantation of a one-piece PMMA IOL in the ciliary sulcus. CONCLUSION: Silicone plate haptic IOLs seem to present special risks for dislocation. Shrinkage of the anterior capsule exerts centripetal forces on the ends of the plate haptic, causing the optic to move posteriorly and to exert pressure against the posterior capsule. If either the posterior or anterior capsule is disrupted by Nd:YAG laser treatment, the forces created by capsular contraction against the flexible lens may cause extension of radial tears and appear to be a substantial risk for further capsule-tearing, releasing the IOL into the vitreous cavity, even months later. The forces of capsular contraction can impart a spring-loading effect on plate haptic silicone lenses. Due to inadequate capsular adherence, these lenses are at risk of posterior dislocation from capsular rents following Nd:YAG laser treatment.

Aged↗

A comparative study of unilateral dislocated mandibular condyle fractures in the rabbit.

PURPOSE: The purpose of this study was to clarify the influence of patients age and the degree of dislocation on the healing of mandibular condyle fractures. MATERIAL AND METHODS: Sixty-two Japanese white rabbits (30 adolescent and 30 adult ones) were used. They underwent unilateral condylar neck osteotomy. The proximal fragments were positioned differently. In group I animals, the fragments were reduced into the original position, in group II animals the small fragment was dislocated 55-90 degrees to the ramus. In group III animals the proximal fragment was dislocated 135 degrees to the ramus. Gross and microscopic assessment was performed 4, 6, 8, 12 and 24 weeks postoperatively. RESULTS: In adolescent animals, complete healing of the fracture was observed, irrespective of the degree of dislocation. In the adult animals, there was complete healing of the fractures in groups I and II. In group III animals, there was a decrease of ramus height accompanied by some fibro-cartilaginous changes. CONCLUSION: Even in rabbits condylar deformation has been found following heavily dislocated artificial condylar fractures in adult animals. This result will help to decide for or against surgical treatment of condylar fractures in humans.

Age Factors↗

Phacoemulsification of dislocated lens and suture fixation of intraocular lens using a perfluorocarbon liquid.

The objective was to describe a new surgical technique to manage a posteriorly dislocated crystalline lens. Four patients with posteriorly dislocated lenses were studied. Two patients had dislocated lenses secondary to trauma, 1 had undergone retinal detachment surgery, and 1 had an idiopathic lens dislocation. Pars plana vitrectomy was carried out on all 4 eyes, followed by an injection of perfluoro-n-octane to float the lens off the retina. The lens was phacoemulsified through a limbal incision, and an intraocular lens was positioned in the ciliary sulcus with suture fixation. Perfluoro-n-octane was replaced by a balanced salt solution. Postoperative visual acuity ranged from 1.0-1.5. Transient choroidal detachment and hypotony were observed in 3 eyes in the early postoperative period. Postoperative ocular hypertension was noted in 2 eyes and was well-controlled with topical antiglaucoma agent. These results indicate that limbal lensectomy of a posteriorly dislocated lens using perfluorocarbon liquids is a beneficial and relatively safe method.

Fluorocarbons↗

Pars plana suture fixation for intraocular lenses dislocated into the vitreous cavity using a closed-eye cow-hitch technique.

We describe a modified intraocular cow-hitch technique for pars plana suture fixation of intraocular lenses (IOLs) that dislocated into the vitreous cavity in 3 patients who had a 3-port vitrectomy and IOL implantation because of retinal disease. To reposition the dislocated IOL after the residual vitreous was removed, 2 additional sclerotomies for suture fixation were made 3.0 mm posterior to the limbus. A loop (cow-hitch knot) was made with 10-0 polypropylene for suture fixation. After the neck of the cow-hitch loop was grasped with an intraocular forceps, the loop was used to lasso a haptic of the dislocated IOL, which was then pulled forward to the sclerotomy. The same procedure was used for the other haptic, and both sutures were secured to the sclera under scleral flaps. In all patients, the dislocated IOLs were repositioned without the need for extraction. The procedures were uneventful. Pars plana suture fixation with the intraocular cow-hitch technique can be used to reposition an IOL that has dislocated into the vitreous cavity.

Adult↗

Anterior intraocular lens dislocation after combined cataract extraction trabeculectomy.

PURPOSE: To evaluate the incidence, cause, and effect of intraocular lens (IOL) dislocation after combined cataract extraction and trabeculectomy. SETTING: An ophthalmic ambulatory surgery center in Lynwood, California. METHODS: This retrospective study comprised 150 patients with open-angle glaucoma who had either planned extracapsular cataract extraction (ECCE) (n = 96) or phacoemulsification (n = 54) combined with IOL implantation and trabeculectomy. I reviewed type of cataract extraction, preoperative glaucoma medications, axial length, and amount of filtration achieved postoperatively. RESULTS: The lens dislocated in 20 eyes (13.3%), with the highest incidence after planned ECCE (18.7%) and the lowest after phacoemulsification with capsulorhexis (3.7%). Eighteen of 30 eyes (60%) that had excessive filtration also had IOL dislocation. Mean induced postoperative myopia in eyes with lens dislocation was-2.25 diopters (D) +/- 0.55 (SD). CONCLUSIONS: Anterior IOL dislocation was related to increased postoperative filtration and was more common after planned ECCE. In all cases, it caused a distorted pupil, posterior synechias, and induced myopia of over -1.00 D.

Anterior Chamber↗

Visual outcome after management of a posteriorly dislocated lens nucleus during phacoemulsification.

PURPOSE: To evaluate the characteristics of eyes with a posteriorly dislocated lens nucleus during phacoemulsification and to assess the results of the management. SETTING: Department of Ophthalmology, Nagoya University School of Medicine, Nagoya, Japan. METHODS: Fifteen eyes (15 patients) with posteriorly dislocated lens nuclei during phacoemulsification were evaluated retrospectively. Patients ranged in age from 56 to 86 years old (mean 73.9 years +/- 9.6 [SD]). Thirteen of the 15 eyes had advanced cataract with hard nucleus before surgery Three patients developed secondary glaucoma resulting from the lens particle after nuclear dislocation. RESULTS: One dislocated lens nucleus was not removed surgically and only observed. In three patients, an attempt had been made to remove the dislocated lens nucleus at the time of cataract surgery. This caused massive choroidal hemorrhage with giant retinal tear, posterior retinal tear, and ora tear, respectively. Finally, the displaced nucleus was removed in 14 patients who had a pars plana vitrectomy at the time of cataract surgery (4 eyes) or a secondary procedure (10 eyes). In 5 eyes, liquid perfluorocarbon was used for the procedure. An intraocular lens (IOL) was successfully implanted in all eyes that were expected to have IOL implantation before surgery except in 1 eye with choroidal hemorrhage. CONCLUSION: Although the results of secondary management of displaced lens nucleus were fairly good, surgeons should take great care to avoid serious secondary complications such as retinal detachment and massive choroidal hemorrhage.

Aged↗

Striped iron zoning of olivine induced by dislocation creep in deformed peridotites.

Deformation of solid materials affects not only their microstructures, but also their microchemistries. Although chemical unmixing of initially homogeneous multicomponent solids is known to occur during deformation by diffusion creep, there has been no report on their chemical zoning due to deformation by dislocation creep, in either natural samples or laboratory experiments. Here we report striped iron zoning of olivine ((Mg,Fe)2SiO4) in deformed peridotites, where the iron concentration increases at subgrain boundaries composed of edge dislocations. We infer that this zoning is probably formed by alignment of edge dislocations dragging a so-called Cottrell 'atmosphere' of solute atoms (iron in this case) into subgrain boundaries during deformation of the olivine by dislocation creep. We have found that the iron zoning does not develop in laboratory experiments of high strain rates where dislocations move too fast to drag the Cottrell atmosphere. This phenomenon might have important implications for the generation of deep-focus earthquakes, as transformation of olivine to high-pressure phases preferentially occurs in high-iron regions, and therefore along subgrain boundaries which would be preferentially aligned in plastically deformed mantle peridotites.

Journal Article↗