Application Of Individualized 3D Guide Plate In The Treatment Of Recurrent Patellar Dislocation

Objective: According to the preoperative three-dimensional CT data of knee joints of patients with recurrent patellar dislocation,combined with 3D printing technology and reverse engineering principle,a 3D printing guide template for locating the insertion of the medial patellofemoral ligament was designed and applied in surgery.Meanwhile,the patient was treated with the reconstruction of the medial patellofemoral ligament combined with the medial patellotibial ligament for recurrent patellar dislocation.The accuracy and application effect of the two methods were evaluated systematically compared with the traditional perspective positioning of the legal position of femoral tunnel insertion.Methods: The clinical data of 30 patients(30 knees)with recurrent patellar dislocation admitted to the Second Affiliated Hospital of Bengbu Medical College from January 2016 to February 2022 were retrospectively analyzed.They were divided into two groups according to different surgical methods.All patients had completed the anteroposterior and lateral knee joint,three-dimensional knee joint CT,and MRI before surgery.Fifteen patients were treated as a control group by traditional perspective positioning of legal femoral tunnel insertion.Fifteen patients(guide plate group)designed and printed 3D individualized femoral tunnel stop guide templates with 3D printing technology to assist in locating the femoral tunnel.The three-dimensional CT data of the preoperative knee joint were imported into the computer software,and the guide plate assisting in the reconstruction of the medial patellofemoral ligament was designed on the computer based on the principle of reverse engineering.Then,the knee joint model and guide template with a ratio of 1:1 to the entity were printed by 3D printing technology for a simulated positioning test,which verified that the guide plate could accurately locate the medial patellofemoral ligament in operation.There were nine males and 6 females in the guide group,ranging in age from 13 to 20 years old,with an average age of(17.47±2.10).In the control group,there were 10 males and 5 females,ranging in age from 13 to 21 years old,with an average age of(16.20±1.47).The information of postoperative re-dislocation and complications in the two groups was collected,and the operation time and fluoroscopy times of the two groups were collected and compared.Lysholm score,IKDC score,Kujala score and VAS score before surgery,3 months and 12 months after surgery were recorded and statistically analyzed to evaluate the clinical effect.All patients underwent a three-dimensional CT examination of the knee joint after surgery,and the accuracy of femoral tunnel location was evaluated according to Servien’s evaluation method.Results: At 12 months after surgery,all patients’ patella extrapolation test and patella fear test were negative and no patella dislocation occurred again.No infection,joint stiffness,deep venous thrombosis,or other complications occurred in the knee joint and incision.The operation time([16.87±3.25] minutes)and intraoperative fluoroscopy times([3.60±1.18] times)in the guide group were significantly less than those in the control group([26.07±4.08] minutes)and([11.80±3.21 times]),with statistical significance(P<0.05).Lysholm score,IKDC score and Kujala score in both groups gradually improved before surgery,3 months and 12 months after surgery,and VAS score was gradually decreased,which was significantly better than before surgery(P<0.05).However,there was no significant difference in Lysholm score,IKDC score,Kujala score and VAS score between the two groups before surgery,3 months and 12 months after surgery(P>0.05).Through comparison,it was found that the positioning accuracy of the guide group was higher than that of the control group,and the difference between the two groups was statistically significant(P<0.05).Conclusion: MPFL combined with MPTL reconstruction in the treatment of recurrent patellar dislocation can obtain a stable trochlear trajectory with good short-term clinical efficacy and safe and reliable technical operation.The positioning of medial patellofemoral ligament insertion assisted by 3D printing reflects the principle of personalized positioning,which is more accurate,reduces the number of fluoroscopies and the learning curve,and is worthy of clinical promotion.