GM-CSF inhibits glial scar formation and shows long-term protective effect after spinal cord injury

OBJECT

This study investigated the effects of granulocyte macrophage-colony stimulating factor (GM-CSF) on the scar formation and repair of spinal cord tissues in rat spinal cord injury (SCI) model.

METHODS

Sprague-Dawley male rats (8 weeks old) were randomly divided into the sham-operated group, spinal cord injury group, and injury with GM-CSF treated group. A spinal cord injury was induced at T9/10 levels of rat spinal cord using a vascular clip. GM-CSF was administrated via intraperitoneal (IP) injection or on the dural surface using Gelfoam at the time of SCI. The morphological changes, tissue integrity, and scar formation were evaluated until 4 weeks after SCI using histological and immunohistochemical analyses.

RESULTS

The administration of GM-CSF either via IP injection or local treatment significantly reduced the cavity size and glial scar formation at 3-4 weeks after SCI. GM-CSF also reduced the expression of core proteins of chondroitin sulfate proteoglycans (CSPGs) such as neurocan and NG2 but not phosphacan. In particular, an intensive expression of glial fibriallary acidic protein (GFAP) and neurocan found around the cavity at 4 weeks was obviously suppressed by GM-CSF. Immunostaining for neurofilament (NF) and Luxol fast blue (LFB) showed that GM-CSF preserved well the axonal arrangement and myelin structure after SCI. The expression of GAP-43, a marker of regenerating axons, also apparently increased in the rostral grey matter by GM-CSF.

CONCLUSION

These results suggest that GM-CSF could enhance long-term recovery from SCI by suppressing the glial scar formation and enhancing the integrity of axonal structure.

Comparison study of intraarticular and intravenous gadolinium-enhanced magnetic resonance imaging of cartilage in a canine model

BACKGROUND

Magnetic resonance (MR) imaging and measurement of glycosaminoglycan (GAG) have potential for characterization of hyaline articular cartilage. Recently, some reports have demonstrated the potential of direct administration of contrast media for MR imaging of cartilage.

PURPOSE

To prove the feasibility of intraarticular gadolinium-enhanced MR imaging of cartilage (iGEMRIC) and T1 relaxation mapping of the articular cartilage in vivo with intraarticular injection of Gd-DTPA2-.

MATERIAL AND METHODS

Five healthy beagle dogs underwent MR imaging and T1 relaxation mapping of the knee joints of both hind legs. The delayed gadolinium-enhanced MR imaging of cartilage (dGEMRIC) and iGEMRIC techniques were interchanged with MR imaging. For dGEMRIC, a double routine dose of Gd-DTPA2- (0.2 mM/kg) was administered intravenously. For iGEMRIC, 2.5 and 1.25 mmol/l saline-diluted Gd-DTPA2- solutions were separately injected into the right and left knee joints, respectively, prior to MR imaging. Color-coded T1 maps of 20 femoral condyles were obtained from the dGEMRIC and iGEMRIC images. The signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and glycosaminoglycan (GAG) delineation of articular cartilage were compared between the dGEMRIC and iGEMRIC techniques.

RESULTS

The mean SNR was higher with dGEMRIC than with iGEMRIC, but the difference was not statistically significant (P=0.174). The mean (+/-SD) CNR was higher with iGEMRIC (-11.6+/-3.4) than with dGEMRIC (-16.7+/-4.0; P=0.000), although the absolute value of the CNR was higher with dGEMRIC. The layering and gradient distribution of GAG were more clearly visualized on the iGEMRIC images. The mean scores of GAG delineation with dGEMRIC and iGEMRIC were 0.7+/-0.6 and 2.2+/-1.7, respectively. The iGEMRIC method better visualized GAG distribution (P=0.001).

CONCLUSION

Although the SNR did not differ significantly between the iGEMRIC and dGEMRIC techniques, the color-coded T1 map produced with iGEMRIC allowed better cartilage evaluation. Thus, iGEMRIC exhibits the useful features of both MR arthrography and dGEMRIC, and provides a color-coded T1 map that is useful for diagnosing early articular cartilage damage.

Low-Intensity Ultrasound (LIUS) as an Innovative Tool for Chondrogenesis of Mesenchymal Stem Cells (MSCs)

Mesenchymal stem cells (MSCs) have a capacity to differentiate into the chondrogenic lineage and are a valuable allogenic source for cartilage tissue engineering. However, they still have critical limitations of relatively inefficient chondrogenic differentiation in vitro and of dedifferentiation and/or hypertrophic changes at late stages of differentiation. Numerous approaches using biochemical and mechanical factors have been tried but have so far failed to overcome these problems. Recent studies by other groups and ours have shown that low-intensity ultrasound (LIUS) is an efficient tool for promoting the chondrogenic differentiation of MSCs both in vitro and in vivo. A series of our experiments suggests that LIUS not only induces chondrogenic differentiation of MSCs but also has diverse additional activities that enhance the viability of MSCs, increase possibly the integrity of the differentiated tissues and delays hypertrophic changes during differentiation. Therefore, LIUS could be an innovative and versatile tool for chondrogenic differentiation of MSCs and for cartilage tissue engineering.

Low-intensity ultrasound inhibits apoptosis and enhances viability of human mesenchymal stem cells in three-dimensional alginate culture during chondrogenic differentiation

Many studies have investigated optimal chondrogenic conditions, but only a few of them have addressed their effects on cell viability or the methods to enhance it. This study investigated the effect of low-intensity ultrasound (LIUS), a well-known chondrogenic inducer, on the viability of human mesenchymal stem cells (hMSCs) during chondrogenic differentiation in three-dimensional (3-D) alginate culture. The hMSCs/alginate layer was cultured in a chondrogenic defined medium and treated with transforming growth factor-beta1 (TGF-beta1) and/or LIUS for 2 weeks. Along with chondrogenic differentiation for 2 weeks, the 3-D alginate culture and TGF-beta1 treatment resulted in the decrease of cell viability, which appeared to be mediated by apoptosis. In contrast, co-treatment with LIUS clearly enhanced cell viability and inhibited apoptosis under the same conditions. The effect of LIUS on the apoptotic event was further demonstrated by changes in the expression of apoptosis/viability related genes of p53, bax, bcl-2, and PCNA. These results suggest that the LIUS treatment could be a valuable tool in cartilage tissue engineering using MSCs as it enhances cell viability and directs the chondrogenic differentiation process, its well-known activity.

Preconditioning of mesenchymal stem cells with low-intensity ultrasound for cartilage formation in vivo

The purpose of this study was to evaluate the benefits of in vitro preconditioning of mesenchymal stem cells (MSCs) using low-intensity ultrasound (US) in the induction of chondrogenic differentiation of MSCs in vivo. After rabbit bone marrow-derived MSCs were seeded onto a polyglycolic acid (PGA) scaffold, the PGA-MSCs constructs were divided into 4 subgroups: untreated control, low-intensity US group, transforming growth factor-beta [TGF]-treated group and low-intensity US/TGF group. The chondrocyte-seeded PGA construct served as a positive control. For 1 week before implantation, the low-intensity US groups were subjected to ultrasound treatment for 20 min daily at an intensity of 200 mW/cm(2). The TGF groups were treated with 10 ng/mL TGF-beta1. The cells were then implanted into the nude mouse subcutaneously. Retrieved 1, 2, 4, and 6 weeks after implantation, each construct underwent gross examination, histology, biochemical assays, mechanical testing, and reverse transcriptase polymerase chain reaction (RT-PCR). Substantial size reduction and blood invasion were found much earlier in the groups that did not undergo low-intensity US than in those that did. Safranin O/Fast green staining revealed that the chondrogenic differentiation of MSCs was more widespread throughout the constructs in the low-intensity US groups. In the biochemical and mechanical analyses, the low-intensity US and low-intensity US/TGF groups were significantly better in forming hyaline cartilage-like tissue by 4 weeks than the non-low-intensity US groups. Presented by von Kossa staining, the development of osteogenic phenotypes was highly suppressed until 4 weeks in the low-intensity US groups, along with compressive strength comparable to the positive control. In the RT-PCR analysis before implantation, the messenger RNA levels of Sox-9, aggrecan, and tissue inhibitors of metalloproteinase-2 were higher in the low-intensity US groups, while those of type I and type X collagens and matrix metalloproteinase-13 were higher in the non-low-intensity US groups. Blood invasion into the constructs was also considerably hindered in the low-intensity US groups. These results strongly indicate that low-intensity US preconditioning in vitro could be an effective cue to upregulate chondrogenic differentiation of MSCs in vivo.

An electromagnetic compressive force by cell exciter stimulates chondrogenic differentiation of bone marrow-derived mesenchymal stem cells

In this study, we present a biological micro-electromechanical system and its application to the chondrogenic differentiation of rabbit bone marrow-derived mesenchymal stem cells (MSCs). Actuated by an electromagnetic force, the micro cell exciter was designed to deliver a cyclic compressive load (CCL) with various magnitudes. Two major parts in the system are an actuator and a cartridge-type chamber. The former has a permanent magnet and coil, and the latter is equipped with 7 sample dishes and 7 metal caps. Mixed with a 2.4% alginate solution, the alginate/MSC layers were positioned in the sample dishes; the caps contained chondrogenic defined medium without transforming growth factor-beta (TGF-beta). Once powered, the actuator coil-derived electromagnetic force pulled the metal caps down, compressing the samples. The cyclic load was given at 1-Hz frequency for 10 min twice a day. Samples in the dishes without a cap served as a control. The samples were analyzed at 3, 5, and 7 days after stimulation for cell viability, biochemical assays, histologic features, immunohistochemistry, and gene expression of the chondrogenic markers. Applied to the alginate/MSC layer, the CCL system enhanced the synthesis of cartilage-specific matrix proteins and the chondrogenic markers, such as aggrecan, type II collagen, and Sox9. We found that the micromechanically exerted CCL by the cell exciter was very effective in enhancing the chondrogenic differentiation of MSCs, even without using exogenous TGF-beta.

Collagenous fibril texture of the discoid lateral meniscus

PURPOSE

To provide the theoretic basis for treatment and to increase the understanding of the tear patterns of the discoid meniscus, we observed the collagen orientation of the discoid meniscus.

METHODS

Ten meniscus specimens were used to observe the collagen fibril orientation of the complete type of the discoid lateral menisci. The samples were observed layer by layer under a polarizing filter microscope by using Sirius red staining, and they were also observed under a scanning electron microscope.

RESULTS

The lateral discoid meniscus is classified into 7 layers based on collagen fibril orientation. The femoral surface of the discoid meniscus is covered by dense and well-arranged thick fibrils, which very much resembles a bunched streak. The fibrils show a sagittal isotropic-arranged orientation. However, the tibial surface shows an irregular and anisotropically arranged orientation. In the outer layer, a meshwork of thin fibrils has been observed. The collagen fibrils in the inner layer are radially orientated from the lateral side to the medial side. In the central layer, the peripheral collagen fibrils are displayed as dense bundles running in a circumferential pattern, whereas its medial zone shows as thin, loosely, and irregularly arranged fibrils without a bundle formation. The anterior and posterior zones of the central layer show the collagen fibrils with a straight arrangement in the radial direction.

CONCLUSIONS

In the lateral middle zone of discoid meniscus, the collagen fibrils run parallel to the periphery of the meniscus. Therefore, it would be ideally suited for resisting hoop stresses. From this anatomic study, it is apparent that the peripheral portion of the meniscus is constructed to bear a load.

CLINICAL RELEVANCE

It is strongly recommended that the peripheral portion of the discoid meniscus should be preserved when a resection of the meniscus is mandatory.

Complete spinal cord injury treatment using autologous bone marrow cell transplantation and bone marrow stimulation with granulocyte macrophage-colony stimulating factor: Phase I/II clinical trial

To assess the safety and therapeutic efficacy of autologous human bone marrow cell (BMC) transplantation and the administration of granulocyte macrophage-colony stimulating factor (GM-CSF), a phase I/II open-label and nonrandomized study was conducted on 35 complete spinal cord injury patients. The BMCs were transplanted by injection into the surrounding area of the spinal cord injury site within 14 injury days (n = 17), between 14 days and 8 weeks (n = 6), and at more than 8 weeks (n = 12) after injury. In the control group, all patients (n = 13) were treated only with conventional decompression and fusion surgery without BMC transplantation. The patients underwent preoperative and follow-up neurological assessment using the American Spinal Injury Association Impairment Scale (AIS), electrophysiological monitoring, and magnetic resonance imaging (MRI). The mean follow-up period was 10.4 months after injury. At 4 months, the MRI analysis showed the enlargement of spinal cords and the small enhancement of the cell implantation sites, which were not any adverse lesions such as malignant transformation, hemorrhage, new cysts, or infections. Furthermore, the BMC transplantation and GM-CSF administration were not associated with any serious adverse clinical events increasing morbidities. The AIS grade increased in 30.4% of the acute and subacute treated patients (AIS A to B or C), whereas no significant improvement was observed in the chronic treatment group. Increasing neuropathic pain during the treatment and tumor formation at the site of transplantation are still remaining to be investigated. Long-term and large scale multicenter clinical study is required to determine its precise therapeutic effect. Disclosure of potential conflicts of interest is found at the end of this article.

Human Amniotic Membrane as a Delivery Matrix for Articular Cartilage Repair

The purpose of this study is to evaluate the feasibility of human amniotic membrane (HAM) as a chondrocyte carrier by assessing cell proliferation and maintenance of phenotype in vitro and cartilage regeneration in vivo. Intact HAM was treated with 0.1% trypsin-ethylenediaminetetraacetic acid (EDTA) for 15 min and the epithelial cells removed to make a denuded HAM. Rabbit articular chondrocytes were then seeded on three different HAM substrates: the epithelial side of intact HAM (IHE), basement side of denuded HAM (DHB), and stromal side of denuded HAM (DHS). These cell-substrate specimens were cultured for up to 4 weeks, and cell proliferation rate and phenotypic stability were examined at weeks 1 and 4. While chondrocytes grew in monolayer fashion on the surface of IHE and DHB substrates, the cells seeded in DHS penetrated and spread into the whole thickness of the stromal layer. The proliferating activity of chondrocytes in DHB was continuously up-regulated. A similar proliferating activity was observed in DHS in the first week, which remained stable for up to 4 weeks. The expression of type II collagen gradually increased with time in the DHS group, while it gradually decreased in the DHB group or was not detected at all in the IHE group. These results suggested that denuded HAM was able to support chondrocyte proliferation and maintenance of phenotype in vitro, seemingly more favorable when DHS was used. Based on this data, the DHS with chondrocytes was used to cover rabbit osteochondral defect with the stromal side facing in. The defect area was successfully regenerated with hyaline cartilage in the Safranin-O stain and International Cartilage Repair Society (ICRS) scoring after 8 weeks of implantation. In conclusion, our findings suggest that denuded HAM could be one of the ideal cell carrier matrices for cartilage regeneration.

Tissue transglutaminase is essential for integrin-mediated survival of bone marrow-derived mesenchymal stem cells

Autologous mesenchymal stem cell (MSC) transplantation therapy for repair of myocardial injury has inherent limitations due to the poor viability of the stem cells after cell transplantation. Adhesion is a prerequisite for cell survival and also a key factor for the differentiation of MSCs. As a novel prosurvival modification strategy, we genetically engineered MSCs to overexpress tissue transglutaminase (tTG), with intention to enhance adhesion and ultimately cell survival after implantation. tTG-transfected MSCs (tTG-MSCs) showed a 2.7-fold and greater than a twofold increase of tTG expression and surface tTG activity, respectively, leading to a 20% increased adhesion of MSCs on fibronectin (Fn). Spreading and migration of tTG-MSCs were increased 4.75% and 2.52%, respectively. Adhesion of tTG-MSCs on cardiogel, a cardiac fibroblast-derived three-dimensional matrix, showed a 33.1% increase. Downregulation of tTG by transfection of small interfering RNA specific to the tTG resulted in markedly decreased adhesion and spread of MSCs on Fn or cardiogel. tTG-MSCs on Fn significantly increased phosphorylation of focal adhesion related kinases FAK, Src, and PI3K. tTG-MSCs showed significant retention in infarcted myocardium by forming a focal adhesion complex and developed into cardiac myocyte-like cells by the expression of cardiac-specific proteins. Transplantation of 1 x 10(6) MSCs transduced with tTG into the ischemic rat myocardium restored normalized systolic and diastolic cardiac function. tTG-MSCs further restored cardiac function of infarcted myocardium as compared with MSC transplantation alone. These findings suggested that tTG may play an important role in integrin-mediated adhesion of MSCs in implanted tissues. Disclosure of potential conflicts of interest is found at the end of this article.

Posterior cruciate ligament reconstruction with a single-sling technique using a tibialis anterior tendon allograft

Reconstruction of the posterior cruciate ligament (PCL) has been performed in various ways. Recent biomechanical tests revealed that a double-bundle graft with a 2-tunnel technique is more likely to restore normal knee stability throughout the full range of knee motion. Several techniques using double-bundle grafts have been implemented for PCL reconstruction; however, each technique has its own advantages and disadvantages. To provide a simplified surgical technique and minimize its inherent complications, the purpose of this study was to introduce a novel technique of arthroscopic PCL reconstruction using an allogeneic tibialis anterior tendon and forming a single sling.

In Vivo Cartilage Tissue Engineering Using a Cell-Derived Extracellular Matrix Scaffold

We have observed in our previous study that a cell-derived extracellular matrix (ECM) scaffold could assure the growth of a cartilage tissue construct in vitro. The purpose of the present study was to evaluate the feasibility of a chondrocyte-seeded cell-derived ECM scaffold by implanting it in vivo in nude mouse. A porous cell-derived ECM scaffold was prepared with a freeze-drying protocol using porcine chondrocytes. Rabbit articular chondrocytes were seeded onto the scaffold and cultured for 2 days in vitro, and then implanted into the nude mouse subcutaneously. They were retrieved at 1, 2, and 3 weeks postimplantation. Under macroscopic analysis, the cartilage-like tissue formation matured with time and developed a smooth, white surface. Contrary to the control (in which no cells were seeded), the size of the neocartilage tissue increased slightly by the third week and remained more stable. Total glycosaminoglycan (GAG) content and the GAG/DNA ratio increased significantly with time in the chemical analysis. The histology exhibited a sustained accumulation of newly synthesized sulfated proteoglycans. Immunohistochemistry, Western blot, and reverse transcriptase-polymerase chain reaction (RT-PCR) clearly identified type II collagen at all time points. Compressive strength of in vivo neocartilage increased from 0.45 +/- 0.06 MPa at 1 week to 1.18 +/- 0.17 MPa at 3 weeks. In conclusion, this study demonstrated that the cell-derived ECM scaffold could provide chondrocytes with favorable in vivo environment to produce a hyaline-like cartilage tissue.

Low-intensity ultrasound stimulates the viability and matrix gene expression of human articular chondrocytes in alginate bead culture

We investigated the effects of low-intensity ultrasound (LIUS) on the activity of human articular chondrocytes isolated from osteoarthritis patients and cultured in the three-dimensional alginate beads. LIUS was treated at 0, 100, 200, and 300 mW/cm(2) for 10 min everyday for 2, 7, or 15 days. LIUS induced the viability of cells only at day 15 but not until day 7 after treatment, when examined by trypan blue exclusion and LIVE/DEAD(R) assay kit. When examined at day 7, the proliferation of cells was not changed by LIUS in the (3)H-thymine incorporation. The expression of matrix producing proteins (type II collagen and proteoglycan) was clearly induced by 200-300 mW/cm(2) LIUS in the incorporation of radioactivity and Northern blot analysis. Although the expression of MMP-1, a matrix degrading protein, was decreased, that of TIMP-1, an inhibitor of MMPs, was not affected by LIUS. Histological analysis revealed an increase in the number and size of glycosaminoglycan-positive lacunae and cellular organelles, appearing as rough endoplasmic reticulum and mitochondria by LIUS. These results showed that the viability and metabolism of human articular chondrocytes in alginate culture was induced by LIUS treatment, suggesting that they could be a promising autologous source for cartilage tissue engineering.

Scaffold-free, engineered porcine cartilage construct for cartilage defect repair--in vitro and in vivo study

This study introduces an implantable scaffold-free (SF) cartilage tissue construct that is composed of chondrocytes and their self-produced extracellular matrix (ECM). Chondrocytes were isolated from the articular cartilages from knees of domestic pigs (2-week old) and monolayer-cultured for 3-4 days in Dulbecco's modified Eagle's medium supplemented with 10% fetal calf serum and 50 microg/mL of ascorbic acid. Briefly treated with 0.25% trypsin-ethylenediaminetetraacetic acid (EDTA), an intact chondrocytes/ECM membrane, as a cell sheet was released from the plate bottom and subsequently centrifuged into a pellet-type construct. Each was grown in vitro for up to 5 weeks and subjected to various assays at different time points (1, 7, 14, 21, and 35 days). For in vivo implantation, full-thickness defects (n = 4) were manually created on the femoro-patellar groove of the left porcine knee and 1-week-cultured SF construct was implanted as an allograft for a month. One defect (#1) was an empty control and the remaining three received different recipes; construct only (#2) or 0.25% trypsin/EDTA-treated first and then construct and collagen gel (#3) or construct and collagen gel (#4). While the total cell numbers significantly increased by 2 weeks and then remained stable, cell viability stayed in the mid-70% range through the entire culture period. Biochemical assay found continuous glycosaminoglycan (GAG) accumulation. Histology exhibited that cell distribution was even in the construct and GAG intensity became stronger and uniform with time. Real-time reverse transcription polymerase chain reaction (RT-PCR) results showed that phenotypic stability peaked at 2 weeks, which was arable to that of freshly isolated chondrocytes. Upon analysis of the retrieved implants, some promising results were witnessed in the defects (#3) retaining not only their intact mass but also chondrocytic morphology with lacuna formation.

Quantitative Analysis of Temporal and Spatial Variations of Chondrocyte Behavior in Engineered Cartilage during Long-Term Culture

In this work, we present the fact that chondrocyte activity differs in relation to their position in an engineered cartilage construct. Chondrocytes from porcine articular cartilage were cultured in a monolayer. Then the cell/extracellular matrix (ECM) membrane was peeled off and centrifuged into a three-dimensional (3D) pellet-type construct. Cultivated in a static condition, the constructs were harvested at specific time intervals (1, 2, 3, and 5 weeks) and manually cored using a biopsy punch to separate the core from the remaining construct. The resultant parts, core and peripheral remnant were thus obtained and subjected to analysis individually. Cell density (10(6 )cells/cm(3)) of the core was significantly higher at 1 week than that of the periphery but this trend was reversed at later time points. Cell viability was remarkably better in the peripheral tissue. Alcian blue staining of glycosaminoglycan (GAG) revealed an intense blue staining from the periphery, exhibiting a steep gradient in distribution of GAG concentration. The gene expression ratio of collagen type II to I appeared to be more altered in the periphery, possibly suggesting cell dedifferentiation, especially at later time points (>2 weeks). The mRNA levels of matrix metalloproteinase-1 (MMP-1) and MMP-13 remained in the normal range, whereas collagen type X expression was more significantly upregulated at the periphery. This study showed that chondrocyte behavior could be highly variable in the extent of their proliferation, differentiation and dedifferentiation, depending on their physical location within 3D engineered cartilage construct.

Low-intensity Ultrasound Stimulation Enhances Chondrogenic Differentiation in Alginate Culture of Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) are regarded as a potential autologous source for cartilage repair, because they can differentiate into chondrocytes by transforming growth factor-beta (TGF-beta) treatment under the 3-dimensional (3-D) culture condition. However, more efficient and versatile methods for chondrogenic differentiation of MSCs are still in demand for its clinical application. Recently, low-intensity ultrasound (LIUS) was shown to enhance fracture healing in vitro and induce chondrogenesis of MSCs in vitro. In this study, we investigated the effects of LIUS on the chondrogenesis of rabbit MSCs (rMSCs) in a 3-D alginate culture and on the maintenance of chondrogenic phenotypes after replating them on a monolayer culture. The LIUS treatment of rMSCs increased: (i) the matrix formation; (ii) the expression of chondrogenic markers such as collagen type II, aggrecan, and Sox-9; (iii) the expression of tissue inhibitor of metalloprotease-2 implicated in the integrity of cartilage matrix; and (iv) the capacity to maintain the chondrogenic phenotypes in a monolayer culture. Notably, LIUS effects were clearly shown even without TGF-beta treatment. These results suggest that LIUS treatment could be an efficient and cost-effective method to induce chondrogenic differentiation of MSCs in vitro for cartilage tissue engineering.

Surgical Treatment for Distal Clavicle Fracture Associated With Coracoclavicular Ligament Rupture Using a Cannulated Screw Fixation Technique

BACKGROUND

A clavicle fracture is a common traumatic injury. However, the high percentage of distal clavicle fractures associated with a rupture of the coracoclavicular (CC) ligament can result in delayed union or nonunion. There is no standard treatment for a clavicle fracture. This report introduces a method for treating distal clavicle fractures associated with a ruptured CC ligament using a cannulated screw.

METHODS

Seventeen patients suffering from a clavicle fracture caused by a rupture of the CC ligament were treated with a closed reduction and a cannulated screw fixation technique. Twelve patients were male and five were female and the average age was 30.5 years (range, 8-64 years). The patients were assessed using a clinical and radiologic evaluation as well as by the University of California at Los Angeles (UCLA) shoulder rating scale for 12 to 16 months after surgery.

RESULTS

After confirming the formation of a callus, the implants were routinely removed approximately 8 weeks after surgery in all patients except for one. In this patient, the implant was removed 16 weeks after surgery as a result of a loosened screw, which caused displacement at the fracture site. During the final follow-up, the fracture site displayed nonunion and a partially limited range of motion (ROM). The shoulder function of the other 16 patients was restored to the preinjury level after 4 approximately 6 months of treatment. In one patient, heterotopic ossification was observed along the CC ligament without any functional deficit. All but one patient showed good results according to the UCLA scale.

CONCLUSIONS

The cannulated screw fixation technique can maintain the rigid fixation of fracture fragments and allow an early return to work and sport activities. Therefore, the cannulated screw fixation technique is expected to be a useful method for treating distal clavicle fractures associated with a coracoclavicular ligament rupture.