Three-dimensional-printed hemi-pelvic prosthesis for revision of aseptic loosening or screw fracture of modular hemi-pelvic prosthesis / 中国修复重建外科杂志

OBJECTIVE@#To investigate the effectiveness of three-dimensional (3D)-printed hemi-pelvic prosthesis for revision of aseptic loosening or screw fracture of modular hemi-pelvic prosthesis.@*METHODS@#Between February 2017 and January 2020, 11 patients with aseptic loosening or screw fracture of modular hemi-pelvic prosthesis were revised using 3D-printed hemi-pelvic prostheses. There were 7 males and 4 females with an average age of 44 years (range, 25-60 years). In the first operation, all patients underwent total tumor resection, modular hemi-pelvic prosthesis reconstruction, and autologous femoral head transplantation. According to the Enneking pelvic partition system, 8 cases were resected in zones Ⅰ+Ⅱ and 3 cases in zones Ⅰ+Ⅱ+Ⅲ. The interval from the initial operation to this revision ranged from 14.3-66.2 months, with an average of 35.8 months. The operation time, the amount of intraoperative bleeding, and the occurrence of complications were recorded. At 6 months after the first operation, before revision, and at last follow-up, the American Musculoskeletal Tumor Society (MSTS) score and Harris score were used to evaluate the recovery of lower limb function. The pain-free walking distance of patients without brace assistance was recorded at last follow-up. X-ray films were taken at 1 month after the first operation, before revision, and at 1 month after revision, the acetabulum position was assessed by the differences in weight arm and cup height between bilateral hip joints. At last follow-up, the digital X-ray tomography was taken to evaluate the prosthesis-bone integration and the occurrence of aseptic loosening.@*RESULTS@#The operation time was 182.6-238.0 minutes (mean, 197.4 minutes). The amount of intraoperative bleeding was 400-860 mL (mean, 550.0 mL). All incisions healed by first intention with no infection, hip dislocation, nerve damage, or vascular-related adverse events. The MSTS score and Harris score at last follow-up were significantly higher than those at 6 months after the first operation and before revision ( P<0.05), while the score before revision was significantly lower than that at 6 months after the first operation ( P<0.05). At last follow-up, the patients were able to walk more than 1 000 meters painlessly without brace assistance. Imaging review showed that the difference of cup height at 1 month after revision was significantly lower than that at 1 month after the first operation and before revision, and at 1 month after the first operation than before revision operation, and the differences were significant ( P<0.05). There was no significant difference in the difference of weight arm among three time points ( P>0.05). All prostheses were well integrated, and no aseptic loosening of the prosthesis or screw fracture occurred.@*CONCLUSION@#Revision with 3D-printed hemi-pelvic prostheses benefited in reconstructing stable pelvic ring and natural bodyweight transmission for patients encountering the aseptic loosening or screw fracture of modular hemi-pelvic prosthesis. Early postoperative rehabilitation training can maximize the recovery of patient limb function, reduce pain during walking, and reduce the incidence of complications.

Static and gait finite element analysis on individualized titanium alloy pelvic prosthesis manufactured by 3D printing / 医用生物力学

Objective To evaluate the biomechanical properties of 3D printed individualized titanium alloy pelvic prosthesis in static and gait states by the method of finite element analysis. Methods Three patients with different types of pelvic tumors were treated by hemi-pelvic arthroplasty with resection of hemi-pelvis. CT and MRI were performed before the surgery, and the corresponding individualized titanium alloy pelvic prostheses were designed. The pelvic models were reconstructed with 3D reconstruction technique, and then assembled with the individualized pelvic prostheses. The human skeletal muscle model was established by AnyBody software to perform gait dynamics analysis. The stress distribution and stress concentration areas of 3 reconstructed pelvic models in static and gait states were obtained by ABAQUS. Results Under both static and gait conditions, the maximum stress of the 3 pelvic prostheses was smaller than the yield strength of the titanium alloy. The pelvic ring of the reconstructed pelvis could meet the rule of stress conduction. The patients’ daily life returned to normal condition after the surgery. Conclusions The effect of 3D prosthetic titanium prosthesis on recovery of pelvic ring is satisfactory, and its effectiveness and stability can meet the requirement of human biomechanics. The analytic results can provide references for clinicians and prosthesis designers.

Computer aided design of 3D printing combined with hemi pelvic replacement surgery / 现代临床护理

Objective To summarize the key points of cooperative nursing care to patients with pelvic, acetabular and peripheral tumors treated with half pelvic prosthesis replacement with computer aided 3D printing. Methods Night patients with pelvic, acetabular and peripheral tumors treated with half pelvic prosthesis replacement with computer aided 3D printing during April 2014 and March 2017 were included in the study. Before replacement, the entity models were printed for confirmation of tumor range, surgical simulation and planning. After resection of tumors, the half pelvic prosthesis by 3D printing was used to reconstruct the bone defects. The points for nursing cooperation were summarized. Result All the patients lived through the replacement and survived by short-term follow-ups, reporting no complications and normal function of hip joint at movement. Conclusion In view of nursing the patients with with pelvic, acetabular and peripheral tumors treated with half pelvic prosthesis replacement with computer aided 3D printing, such nursing measures as careful preoperative preparation for the surgery, specialized nursing assessment, body position nursing, aseptic operation and tumor free technique, dynamic observation of vital signs and close nursing cooperation are critical for the success of half pelvic prosthesis replacement.

Static and gait finite element analysis on individualized titanium alloy pelvic prosthesis manufactured by 3D printing / 医用生物力学

Objective To evaluate the biomechanical properties of 3 D printed individualized titanium alloy pelvicprosthesis in static and gait states by the method of finite element analysis.Methods Three patients with different types of pelvic tumors were treated by hemi-pelvic arthroplasty with resection of hemi-pelvis.CT and MRI were performed before the surgery,and the corresponding individualized titanium alloy pelvic prostheses were designed.The pelvic models were reconstructed with 3D reconstruction technique,and then assembled with the individualized pelvic prostheses.The human skeletal muscle model was established by AnyBody software to perform gait dynamics analysis.The stress distribution and stress concentration areas of 3 reconstructed pelvic models in static and gait states were obtained by ABAQUS.Results Under both static and gait conditions,the maximum stress of the 3 pelvic prostheses was smaller than the yield strength of the titanium alloy.The pelvic ring of the reconstructed pelvis could meet the rule of stress conduction.The patients' daily life returned to normal condition after the surgery.Conclusions The effect of 3D prosthetic titanium prosthesis on recovery of pelvic ring is satisfactory,and its effectiveness and stability can meet the requirement of human biomechanics.The analytic results can provide references for clinicians and prosthesis designers.