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Objective:To evaluate the application of 3D printed osteotomy template in total knee arthroplasty (TKA) for valgus knee.Methods:A retrospective analysis was performed of the 21 patients with valgus knee who had undergone TKA at Department Ⅰ of Joint Surgery, Orthopaedics Hospital of Zhengzhou from March 2016 to February 2018. They were 5 males and 16 females, aged from 62 to 78 years (average, 66.7 years). TKA was performed with the assistance of a 3D printed personalized osteotomy template for each patient. The efficacy of the personalized osteotomy templates was evaluated by comparing the femorotibial angle, knee range of motion, Hospital for Special Surgery (HSS) knee scores of the patients between preoperation and postoperation.Results:The 21 patients were followed up for a mean duration of 16.3 months(range, from 10 months to 4 years). All incisions healed by the first intention. The last follow-ups showed that their preoperative femorotibial angle 17.6°±5.7° was improved significantly to 6.3°±1.2°, their preoperative knee range of motion 71.3°±5.8° increased significantly to 102.4°±7.5°, and their preoperative HSS scores 38.2±5.7 increased significantly to 87.5±3.5 ( P<0.001). Their radiographic evaluation at the last follow-up showed stable prosthetic components with no implant loosing or osteolysis. Conclusion:A personalized 3D printed osteotomy template can be used in TKA for valgus knee, leading to accurate osteotomy, effective correction of mechanical alignment and satisfactory clinical outcomes.
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Objective:To evaluate the application of a 3D printed positioner for hip rotation center in total hip arthroplasty.Methods:From August 2015 to December 2017, 14 patients were treated by unilateral total hip arthroplasty at Department Ⅰ of Joint Surgery, Orthopaedics Hospital of Zhengzhou for avascular necrosis of femoral head or femoral neck fracture. They were 8 males and 6 females with an average age of 51.8 years (from 37 to 65 years). All their surgeries were assisted by a 3D printed positioner for hip rotation center. Postoperatively, the abduction and anteversion of acetabular cup and the hip rotation center were measured, the agreement between the hip rotation center of the affected side (O2) and the anatomical rotation center of the healthy side (O1) was assessed, and the function of the affected hip and complications were recorded at the last follow-up.Results:The 14 patients were followed up for an average of 18 months (from 6 to 24 months). The postoperative ordinates of O2 and O1 were respectively 19.36 mm±3.61 mm and 18.33 mm±3.41 mm while their abscissas 39.93 mm±2.97 mm and 39.99 mm±3.16 mm, indicating agreement between O2 and O1 ( P>0.05). The postoperative abduction and anteversion of the cup were within a normal range (39.3°±3.2°and 14.6°±1.2°, respectively). The last follow-up showed that their preoperative Harris hip scores (42.3±3.2) were significantly improved (94.3±4.7) ( t=2.873, P=0.002) and that 13 cases were rated as excellent and one as good. X-ray follow-up showed good position of their acetabular prostheses, no loosening of the cups or femoral prostheses, and no heterotopic ossification. Conclusion:A 3D printed positioner for hip rotation center can effectively assist reconstruction of the hip rotation center and accurate implantation of acetabular prosthesis in total hip arthroplasty.
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BACKGROUND: The Topping-off technique, which combines lumbar fusion with the dynamic internal fixation system (Coflex), can not only reduce the pressure, but also protect the adjacent segments. There is no relevant mechanical analysis performed on the rationality of the application of Topping-off technique to young patients with the need for fusion on the lumbosacral region and adjacent degenerated segments. OBJECTIVE: To establish a finite element model of Topping-off surgery on the lumbosacral junction and to analyze the biomechanical changes of the adjacent segments and the range of motion trend of the lumbar spine. METHODS: A healthy young male volunteer with no previous history of low back pain or congenital malformations was randomly selected for thin-slice CT scanning after signed the informed consent. The image information was imported into the computer and the whole lumbar spine model as the healthy group model was established by analyzing the image information through Mimics, Geomagic Studio 12.0, HyperMesh and Abaqus successively. After verifying the effectiveness of the model, the moderate degeneration model of intervertebral disc was established by changing the material properties of L4-s1 discs on the basis of the healthy model, and the fusion model and Topping-off model were respectively established on the basis of the degeneration model. After applying 400 N compressive load and 10 N-m momentum to the four groups of models, the variation trends of range of motion from L2 to L5 and the stress changes of L4/L5 intervertebral disc, nucleus pulposus and facet joints were calculated respectively. RESULTS AND CONCLUSION: (1) Compared with the degeneration model, the lumbar range of motion of Topping-off model and fusion model decreased, and the Topping-off model decreased more significantly than the fusion model. (2) The range of motion of fusion model L4-L5 increased significantly and the range of motion of L2/L3 and L3/L4 segments did not change significantly. Compared with the degeneration model, the L4-L5 range of motion of Topping-off model decreased, and range of motion of the L2/L3 and L3/L4 levels increased to some extent in the flexion and extension positions. (3) Compared with the degeneration model, the stress on the disc, nucleus pulposus and facet joint of the fusion model L4-L5 increased in four positions of flexion, extension, rotation and bending, while the fiber stress on the Topping-off model decreased significantly in all four positions. (4) These results suggest that Topping-off technology can not only reduce the stress on the upper adjacent degenerative intervertebral disc, nucleus pulposus and facet joints, but also reduce the hyperactivity of the adjacent segments and increase the range of motion of other upper segments, thereby compensating the lumbar spine mobility and delaying the degeneration of upper adjacent segments.
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Objective To evaluate the efficacy of unilateral atlanto-axial transpedicle screw fixation plus iliac bone graft for treatment of unstable atlas fractures combined with unilateral pedicle dysplasia or comminuted fractures.Methods A retrospective case control study was made on 44 patients with unstable atlas fractures surgically treated between January 2012 to June 2016.Unilateral atlanto-axial transpedicle screw fixation combined with iliac bone graft was performed for 22 patients combined with unilateral pedicle dysplasia or comminuted fractures in Group A[15 males,seven females;(37.5 ± 13.4)years],and bilateral atlanto-axial transpedicle screw fixation combined with iliac bone graft was performed for 22 patients without unilateral pedicle dysplasia or comminuted fractures in Group B [14 males,eight females;(38.1 ± 13.3)years].Between-group differences were compared concerning operation time,intraoperative blood loss,length of hospital stay,success rate of screw placement,postoperative atlantoaxial stability,surgery-related complications,visual analog scale (VAS),Japanese orthopedic association score (JOA) and bone fusion.Results Mean duration of follow-up was 28.4 months (range,14-48 months).In Group A,operation time was (123.4 ± 18.2) min,blood loss was (218.5 ± 80.2) ml,hospital stay was (7.1 ± 1.0)d,success rate of screw placement was 100％,postoperative atlanto-axial stability of all patients was obtained,and no complications occurred.In Group B,operation time was (173.4 ± 12.4) min,blood loss was (318.2 ± 61.7) ml,hospital stay was (7.2 ± 0.8) d,success rate of screw placement was 100％,postoperative atlanto-axial stability of all patients was obtained,and no complications occurred.There were significant differences in operation time and blood loss between the two groups (P ＜0.01),while not in hospital stay,success rate,postoperative atlant-oaxial stability,complication incidence,VAS and JOA (P ＞ 0.05).Conclusion Both treatments are effective,but unilateral atlanto-axial transpedicle screw fixation combined with iliac bone graft is associated with relatively shorter operation time and less blood loss and hence is considered as a better choice for treatment of unstable atlas fractures.
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Objective To establish a porcine model of penetrating-suture pancreaticojejunostomy.Methods Ten domestic pigs were selected,and after general anesthesia they underwent laparotomy and the pancreas was visualized.Then the pancreas was dissected at the level of superior mesenteric vascular,and the proximal pancreatic stump was sewed up.The anastomosis between the distal pancreatic stump and the intestinal wall adopted penetrating-suture pancreaticojejunostomy; the digestive tract was reconstructed by Roux-en-Y.Results The anastomosis with penetrating-suture pancreaticojejunostomy was successful in ten domestic pigs.The mean pancreatic stump diameter was 2.5 cm,and the mean pancreatic duct diameter was 1.5 mm,the mean time for operation was 1.0 ～ 2.5 h,and the average time of pancreaticojejunostomy was 8 minutes.The mean blood loss was 25 ml.After operation,diarrhea occurred in 2 pigs and wound infection occurred in 1 pig,and all were cured with appropriate management.No pig died intra-operatively,and no pancreatic fistula or death occurred after operation.Conclusions A porcine model of penetrating-suture pancreaticojejunostomy is successfully established.