3D Printing Hip Prostheses Offer Accurate Reconstruction,Stable Fixation,and Functional Recovery for Revision Total Hip Arthroplasty with Complex Acetabular Bone Defect

Complicated and large acetabular bone defects present the main challenges and difficulty in the revision of total hip arthroplasty(THA).This study aimed to explore the advantages of three-dimensional(3D)printing technology in the reconstruction of such acetabular bone defects.We retrospectively analyzed the prognosis of four severe bone defects around the acetabulum in three patients who were treated using 3D printing technology.Reconstruction of bone defect by conventional methods was difficult in these patients.In this endeavor,we used radiographic methods,related computer software such as Materialise's interactive medical image control system and Siemens NX software,and actual surgical experience to estimate defect volume,prosthesis stability,and installation accuracy,respectively.Moreover,a Harris hip score was obtained to evaluate limb function.It was found that bone defects could be adequately reconstructed using a 3D printing prosthesis,and its stability was reliable.The Harris hip score indicated a very good functional recovery in all three patients.In conclusion,3D printing technology had a good therapeutic effect on both complex and large bone defects in the revision of THA.It was able to achieve good curative effects in patients with large bone defects.

Management of Severe Femoral Bone Defect in Revision Total Hip Arthroplasty-A 236 Hip,6-14-year Follow-up Study

Summary： This study evaluated the clinical effect of impaction bone graft and distal press-fit fixation for the reconstruction of severe femoral bone defect in revision total hip arthroplasty. A total of 234 patients （involving 236 hips） with Paprosky III and 1V femoral bone defects were treated with the revision total hip arthroplasty from June 1998 to Aug. 2006. Impaction bone graft technique was used for 112 hips, with allogeneic freeze-dried bone as bone graft and SP II as prosthesis. With 124 hips, modular distal press-fit fixation and tapered femoral stem （MP stem） were employed. After the operation, the subjects were followed up on regular basis and results were assessed by using the Harris Hip Score （HHS） and 12-item Short Form Health Survey （SF-12）. Radiolucence, subsidence and loosening were observed and complications, including infection, fracture, dislocation etc. were recorded. A 6-14-year follow-up showed that prostheses failed, due to infection, in 4 patients of impaction bone graft group and that 6 patients in the press-fit fixation group experienced prosthesis failure, with the survival rates for the two techniques being 96.43% and 95.16%, respectively. One-way ANOVA showed that prosthesis survival was significantly associated with surgery-related complications （P〈0.05） and was not related to the type of the bone defects （P〉0.05）. The rate of complications bore significant association with the type of bone defects in the two groups （P〈0.05）. Our study showed that the two revision methods could achieve satisfactory mid-term and long-term results for the reconstruction of severe bone defects. It is of great significance for attaining high prosthesis survival rate to select suitable operation on the basis of the type of bone defect. Careful operative manipulation and post-operative rehabilitation aimed at reducing complications are also important.

Application of 3D-printed prosthesis in revision surgery with large inflammatory pseudotumour and extensive bone defect: A case report

BACKGROUND Hip revision surgery is the final treatment option for the failure of artificial hip joints, but it is more difficult than the initial operation. For patients with hip joint loosening around the prosthesis combined with large inflammatory pseudotumours and large segment bone defects, hip revision is even more difficult, and clinical reports are rare.CASE SUMMARY Male, 59 years old. The patient underwent left hip replacement 35 years ago and was now admitted to hospital due to massive masses in the left thigh, shortening of the left lower extremity, and pain and lameness of the left hip joint. X-ray, computed tomography and magnetic resonance imaging revealed prosthesis loosening, left acetabular bone defect(Parprosky IIIB type), and a bone defect of the left proximal femur(Parprosky IIIA type). Inflammatory pseudotumours were seen in the left hip and left thigh. Hip revision surgery was performed using a 3Dprinted custom acetabular prosthesis was used for hip revision surgery, which was produced by Arcam Electron Beam Melting system with Electron Beam Melting technology. The operation was successful, and the patient was followed up regularly after the operation. The custom-made acetabular prosthesis was well matched, the inflammatory pseudotumour was completely removed, the postoperative hip prosthesis was stable, and the old greater trochanter fracture was well reduced and fixed. The patient was partially weight-bearing with crutches 3 mo after the operation and walked with full weight-bearing after 6 mo. The hip prosthesis was stable, and there was no recurrence of inflammatory pseudotumours at the last follow-up. The Visual Analogue Scale was 3, and the Harris hip score was 90.CONCLUSION The use of 3D-printed personalized custom prostheses for complex hip revision surgery has satisfactory surgical results and has great clinical application value.

Cemented versus uncemented stems for revision total hip replacement:A systematic review and meta-analysis

BACKGROUND The popularity of uncemented stems in revision total hip arthroplasty(THA)has increased in the last decade.AIM To assess the outcomes of both cemented and uncemented stems after mid-term follow up.METHODS This study was performed following both the Preferred Reporting Items for Systematic Reviews and Meta-analyses Statement and the Cochrane Handbook for systematic reviews and meta-analysis guidelines.Articles were chosen irrespective of country of origin or language utilized for the article full texts.This paper included studies that reviewed revision THA for both cemented or uncemented long stems.RESULTS Three eligible studies were included in the meta-analysis.Analysis was conducted by using Review Manager version 5.3.We computed the risk ratio as a measure of the treatment effect,taking into account heterogeneity.We used random-effect models.There were no significant differences found for intraoperative periprosthetic fractures[risk ratio(RR)=1.25;95%confidence interval(CI):0.29-5.32;P=0.76],aseptic loosening(RR=2.15,95%CI:0.81-5.70;P=0.13),dislocation rate(RR=0.50;95%CI:0.10-2.47;P=0.39),or infection rate(RR=0.99,95%CI:0.82-1.19;P=0.89),between the uncemented and the cemented long stems for revision THA after mid-term follow-up.CONCLUSION This study has evaluated the mid-term outcomes of both cemented and uncemented stems at first-time revision THA.In summary,there were no significant differences in the dislocation rate,aseptic loosening,intraoperative periprosthetic fracture and infection rate between the two cohorts.

Femoral Head Autograft to the Iliac for Use in Future Revisions of Total Hip Arthroplasty: 15-Year Follow-Up

Introduction: The therapeutic success of total hip arthroplasty (THA) is unquestionable. However, in young patients, it is still a controversial topic, not because of the results obtained, but because of the presumed need for revision of the prosthetics components in the future. Objectives: The present work performs a retrospective study of patients who underwent THA surgery in the past, in which the femoral head was transferred to the iliac for use in future revisions of total hip arthroplasty (autograft), and describes the proposed technique. Methods: The research reviewed 27 patients operated on using the femoral head autograft technique for the ipsilateral iliac in total hip arthroplasty, performed from 1996 to 2005;the study considered medical records, X-rays and CT scan images, and photographs taken at the time of surgery. Results: To date, only two revisions of total hip arthroplasty have been performed, in which the patients have benefited from the technique of autografting of the femoral head. No case evolved with infection or any other type of complication. All inserted grafts are consolidated and integrated with the iliac. Conclusion: The autograft technique is cheap, simple and reproducible, making available large amounts of bone for use in future revisions of total hip arthroplasty in young patients.

Bone graft incorporation failure with inappropriate limb load transfer can lead to aseptic acetabular loosening of metal-on-metal prosthesis: A case report

BACKGROUND Aseptic acetabular loosening can result from various factors that can be categorized into groups:patient-related,surgeon-related and implant-related.We present a case of a 63-year-old patient who at first underwent a total hip arthro-plasty(THA)using a metal-on-metal bearing due to hip arthrosis.Follow-up visits revealed no complications after the procedure.Two years after the THA,acetabular component loosening occurred due to subsequent trauma of the opposite hip,necessitating a revision THA using a ceramic-on-ceramic bearing.CASE SUMMARY We aim to illustrate a rare case where the primary reason for undergoing THA revision was not only incomplete bone graft incorporation but also improper limb load distribution.Following the revision arthroplasty,a 9-year follow-up visit revealed improvements in all evaluation measures on questionnaire compared to the state before surgery:Harris Hip Score(before surgery:15;after surgery:95),Western Ontario and McMaster Universities Arthritis Index(before surgery:96;after surgery:0),and Visual Analogue Scale(before surgery:10;after surgery:1).CONCLUSION Opposite-hip trauma caused a weight transfer to the limb after a THA procedure.This process led to a stress shielding effect,resulting in acetabular component loosening.

Jumbo cup in hip joint renovation may cause the center of rotation to increase

BACKGROUND Utilizing the large jumbo cup in revision total hip arthroplasty is an effective approach to cure many lacunar and segmental peripheral bone defects.However,with the use of the jumbo cup,the center of the hip joint may become elevated relative to the primary acetabulum,and the diameter of the large cup is greater.AIM To study the height and the significance of the elevation of the hip joint center.METHODS Eighty-eight patients matched the criteria for this condition and were included in the study.The center height of the hip joint was measured relative to the opposite normal hip joint.The diameter of the jumbo cup was measured and checked according to operation notes,and the diameter of the jumbo cup was measured with a prosthesis label.Then,the horizontal and vertical centers of rotation were measured on the surgical side and opposite side.The average center height of the hip joint on the renovated side and the opposite side and the position of the hip cup relative to the teardrop were compared using a paired t-test.RESULTS Radiometric analysis showed that the average hip joint center was elevated by 7.6 mm.The rotational center height delta of the renovated hip was 7.6±5.6 mm,and there was an obvious difference between the two groups(P=0.00).The difference in horizontal distance was 0.5±5.1 mm(-11.5-14.0 mm),and there was no obvious difference between the two groups(P=0.38).According to the foreign standard,the rotational center height delta of the renovated hip was 7.5±6.2 mm,and there was a significant difference between the two groups(P=0.00).There was no obvious difference between the domestic and foreign standards(P>0.05)between the two groups.CONCLUSION The application of the jumbo cup elevates the rotational center of the hip joint,but it is feasible and effective to use the jumbo cup.

Application of Acetabular Reinforcement Ring with Hook for Correction of Segmental Acetabular Rim Defects during Total Hip Arthroplasty Revision

This study investigated the biomechanical micro-motion associated with the application of acetabular reinforcement ring with hook （Ganz ring） for the correction of segmental acetabular rim defects, by finite element analysis. The objective was to determine whether the Ganz ring is suitable for correcting segmental acetabular rim defects at different regions during total hip arthroplasty revision as well as the number of screws required to fix the Ganz ring. A finite element model of the hip joint was generated to simulate and evaluate the insertion and fixation of the Ganz ring and acetabular cup in the context of segmental rim defects in the anterior column, superior portion, and posterior column. Micro-motion was the greatest in the posterior column defect and the least in the anterior column defect. However, the peak stress distribution on the remaining portion of the acetabular rim was the highest in the superior portion defect, following the pos- terior column defect and anterior column defect. Increasing the number of fixations of the Ganz ring did not decrease the micro-motion. We found that the Ganz ring effectively provided biomechanical stability during the reconstruction of the segmental rim defect as long as the screws fixed the Ganz ring well to the host bone.

Fracture of Extensively Porous-Coated Cylindrical Femoral Stem Following Revision Total Hip Arthroplasty

Total hip arthroplasty （THA） is one of the most clinically successful surgeries. Despite the prevalence of THA, the number of revisions for septic or aseptic reasons continues to increase.

Application of Novel Design Bone Grafting for Treatment of Segmental Acetabular Rim Defects During Revision Total Hip Arthroplasty

The study aimed to develop efficient techniques with different novel graft structures to enhance the treatment of acetabular bone deficiency.The inhomogeneous material properties Finite Element Analysis(FEA)model was reconstructed according to computed tomography images based on a healthy patient without any peri-acetabular bony defect according to the American Academy of Orthopedic Surgeons(AAOS).The FEA model of acetabular bone deficiency was performed to simulate and evaluate the mechanical performances of the grafts in different geometric structures,with the use of fixation implants(screws),along with the stress distribution and the relative micromotion of graft models.The stress distribution mainly concentrated on the region of contact of the screws and superolateral bone.Among the different structures,the mortise-tenone structure provided better relative micromotion,with suitable biomechanical property even without the use of screws.The novel grafting structures could provide sufficient biomechanical stability and bone remodeling,and the mortise-tenone structure is the optimal treatment option for acetabulum reconstruction.