The Design And Drilling Accuracy Evaluation Of Commonly-used And Personalized Guide Device In Coracoclavicular Ligament Reconstruction

BackgroundIn most anatomical reconstruction of the coracoclavicular(CC)ligament techniques,a transclavicular-transcoracoid tunnel is necessary,with subsequent insertion and immobilization of the substitute of CC ligament.The tunnel's orientation is important factors in maintaining stability of AC joint after reduction.Since the coracoid process is small in a complex spatial configuration,accurate transclavicular-transcoracoid drilling is a big challenge for physicians—especially with minimally invasive incisions.Several methods have been developed to assist drilling,such as arthroscopy and navigation systems.But they are expensive,skill-demanding.In comparison,guide devices are simple and cost-effective operative tools.However,the existing guide devices could not meet the requirements of transclavicular-transcoracoid drilling with minimally invasive incisions under direct visualization well.In addition,lengths of the ligament substitute and drilling angulations have an impact on prognosis,but there is no relevant morphological measurement.ObjectiveThis study aims to measure the morphological data related to reconstruction of CC ligament,and to design a simple C-shape guide and personalized guides for transclavicular-transcoracoid drilling with minimally invasive incisions under direct visualization based on the morphological data,and to compare their accuracy and efficiency with free-hand technique and the assembly-type guide in specimen experiment.Method1.CT images of adults' shoulder were collected and used to measure morphological data related to CC ligament reconstruction.2.Computer-aided design(CAD)software was used to design the C-shape guide device and personalized guide devices for CC ligament reconstruction.The C-shape,assembly-type and personalized guide devices were produced by 3D printing with photosensitive resin.3.One hundred and twenty human shoulder specimens were randomly assigned into free-hand,C-shape' assembly and personalized groups for transclavicular-transcoracoid drilling by 5 inexperienced surgeons.The drilling was from distal one third of the upper clavicle,which was approximately 3.5 cm medial to the AC joint,to the midpoint of the inferior coracoid base.Operation time and the tunnel location zones on the coracoid's inferior surface were measured.Additionally,distances from the tunnel edge to the coracoid's medial(dm)and lateral(d1)edges were measured to calculate the absolute differences(dd)between them.Result1.The length of trajectories for the conoid ligament reconstruction and the trapezoid ligament reconstruction were 41.1 ± 4.6 mm and 42.4 ± 6.1 mm,respectively.The angulation between ideal lateral clavicle tunnel and long axis of clavicle was 73.4 ± 9.1°.The angulation between ideal lateral clavicle tunnel and anteroposterior axis of clavicle was 88.0±4.1°.2.The operation time in the free-hand group,C-shape group,assembly group and personalized group was 203 ± 33 s,267 ± 62 s,348±71 s,155 ± 14 s,respectively(P<0.001).The tunnel exit points on the inferior coracoid surface located at desired base-central zones were 13(43.3%),28(93.3%),30(100%)and 30(100%)in the free-hand group,C-shape group,assembly group and personalized group,respectively(P<0.001).The absolute differences(dd)between dm and d1 in the freehand,C-shape,assembly groups and personalize group were 3.7±2.0 mm,2.0 ± 0.9 mm,1.0 ± 0.8 mm,0.9±0.5 mm,respectively(P<0.001).Conclusion1.The results provided an anatomical basis for the improvement of the closed loop's length and the drilling angulation.It is recommended that the length of the closed loop should reduce intervals within the range of 30 mm to 57 mm.When establishing the lateral clavicle tunnel,it should be slightly toward anterior and medial.2.The C-shape,assembly-type and personalize guide device all achieved high accuracies in transclavicular-transcoracoid drilling with efficiency.The assembly-type and personalized guide device showed higher accuracy.Considering the factors such as materials and preparation time,the assembly-type guide device might be the better choice for inexperienced surgeons.