Bone graft substitutes in hip revision surgery: a comprehensive overview

Assessment Accuracy of 2D vs. 3D Imaging for Custom-Made Acetabular Implants in Revision Hip Arthroplasty

Revision total hip arthroplasty (rTHA) presents significant challenges, particularly in patients with severe acetabular bone defects. Traditional treatment options often fall short, leading to the emergence of custom-made 3D-printed acetabular implants. Accurate assessment of implant positioning is crucial for ensuring optimal postoperative outcomes and for providing feedback to the surgical team. This single-center, retrospective cohort study evaluates the accuracy of standard 2D radiographs versus 3D CT scans in assessing the positioning of these implants, aiming to determine if 2D imaging could serve as a viable alternative for the postoperative evaluation. We analyzed the implant positions of seven rTHA patients with severe acetabular defects (Paprosky ≥ Type IIIA) using an alignment technique that integrates postoperative 2D radiographs with preoperative CT plans. Two independent investigators, one inexperienced and one experienced, measured the positioning accuracy with both imaging modalities. Measurements included translational shifts from the preoperatively templated implant position in the craniocaudal (CC), lateromedial (LM), and ventrodorsal (VD) directions, as well as rotational differences in anteversion (AV) and inclination (INCL). The study demonstrated that 2D radiographs, when aligned with preoperative CT data, could accurately assess implant positions with precision nearly comparable to that of 3D CT scans. Observed deviations were 1.4 mm and 2.7 mm in CC and LM directions, respectively, and 3.6° in AV and 0.7° in INCL using 2D imaging, all within clinically acceptable ranges. For 3D CT assessments, mean interobserver variability was up to 0.9 mm for translational shifts and 1.4° for rotation, while for 2D alignment, observer differences were 1.4 mm and 3.2° for translation and rotation, respectively. Comparative analysis of mean results from both investigators, across all dimensions (CC, LM, AV, and INCL) for 2D and 3D matching, showed no significant differences. In conclusion, conventional anteroposterior 2D radiographs of the pelvis can sufficiently determine the positioning of custom-made acetabular implants in rTHA. This suggests that 2D radiography is a viable alternative to 3D CT scans, potentially enhancing the implementation and quality control of advanced implant technologies.

Custom-made implants for massive acetabular bone loss: accuracy with CT assessment

BACKGROUND

Custom-made implants are a valid option in revision total hip arthroplasty to address massive acetabular bone loss. The aim of this study was to assess the accuracy of custom-made acetabular implants between preoperative planning and postoperative positioning using CT scans.

METHODS

In a retrospective analysis, three patients who underwent an acetabular custom-made prosthesis were identified. The custom-made designs were planned through 3D CT analysis considering surgical points of attention. The accuracy of intended implants positioning was assessed by comparing pre- and postoperative CT analyzing the center of rotation (CoR), anteversion, inclination, screws, and implant surface in contact with the bone.

RESULTS

The three cases presented satisfactory accuracy in positioning. A malpositioning in the third case was observed due to the posterization of the CoR of the implant of more than 10 mm. The other CoR vectors considered in the third patient and all vectors in the other two cases fall within 10 mm. All the cases were positioned with a difference of less than 10° of anteversion and inclination with respect to the planning.

CONCLUSIONS

The current case series revealed promising accuracy in the positioning of custom-made acetabular prosthesis comparing the planned implant in preoperative CT with postoperative CT.

Debridement without bone grafting prevents osteolytic lesions progression in revision THAs with prosthesis revised

Background

Bone defects in revision total hip arthroplasties (rTHAs) caused by osteolysis are routinely treated with autografts or allografts, despite their various disadvantages. Currently, little is known about the prognosis of ungrafted cavities with complete debridement following prosthetic revision in rTHAs with component loosening, as few reports have focused on the application of debridement without bone grafting in osteolytic lesions that do not compromise structural stability in revision THAs with revised components.

Methods

In this study, 48 patients receiving rTHAs with components revised for aseptic loosening with osteolysis between 2015 and 2019 were included. Anteroposterior and lateral radiographs of hips before and after revision surgery and last follow-up were compared to measure whether the size of the debrided osteolytic cavity without bone graft had changed.

Results

In total, 48 patients with 59 osteolytic lesions were enrolled. The mean follow-up period was 3.33 years (range 2-6 years). None of the 59 cavities had progressed at the last follow-up, and 11 (18.6%) regressed. Two patients underwent re-revision according to dislocation during follow-up.

Conclusion

In rTHAs with revised components, osteolytic lesions that do not influence structural stability could be debrided without grafting to avoid the disadvantages of grafting. Debridement and component revision are sufficient to prevent the progression of osteolytic lesions during surgery, without having adverse effects on the short-to mid-term prognosis.

Minimum 10 years clinical and radiological outcomes of acetabular revisions of total hip arthroplasties with tricalcium phosphate/hydroxyapatite bone graft substitute

BACKGROUND

Aseptic loosening is the most frequent indication for revision of total hip arthroplasty. Revision arthroplasty of acetabular component is a challenge for every surgeon because they have to simultaneously deal with the reconstruction of bone defects, adequate implant geometry and stable fixation. Allografts are the most frequently used materials in reconstruction of bone loss during revision surgeries. Because of an increasing number of revision hip arthroplasties and poor availability of allografts, we decided to use bone graft substitutes in acetabular revisions.

METHODS

Between September 2005 and January 2010, 44 revision arthroplasties in 43 patients were performed with the use of bone graft substitutes for acetabular defect reconstruction in revision of total hip arthroplasty. Acetabular bone defects were classified according to Paprosky. Seventeen hips were classified as IIA, 3 hips IIB, 3 hips IIC, 10 hips IIIA and 11 hips IIIB. Acetabular bone defects were reconstructed with tricalcium phosphate/hydroxyapatite bone graft substitute - BoneSave. Clinical and radiological examination was performed after 3 months, 1 year and then annually. Harris hip score was used for clinical evaluation. Survival analysis was performed with Kaplan-Meier method with aseptic loosening as the definition of endpoint.

RESULTS

The average follow-up period is 12 (range from 10 to 15) years. During the follow-up, three patients died after 24 months because of causes not related to surgery. None of the patients was lost to follow-up. The evaluation of clinical results revealed an increase in pre-operative HHS from average 38.3 (range 25 to 55) points to average 86.3 (range 45 to 95) points at the most recent follow-up. Radiographic evaluation showed the migration of one revision cage 12 months after surgery. Revision arthroplasty performed after 14 months revealed the partial incorporation of bone graft substitute. There were not any cases of loosening of revision acetabular cup at the most recent follow up examination in the remaining 39 patients. Bone graft substitute was not absorbed in all of these patients. The survival after 10 years amounted to 97.56%.

CONCLUSION

Bone graft substitute Bone Save may be suitable for acetabular revision surgery, however preoperative bone defect is critical for success and determining of a surgical technique, so this is multifactorial in this challenge surgery.

Effect of Chemically Induced Hypoxia on Osteogenic and Angiogenic Differentiation of Bone Marrow Mesenchymal Stem Cells and Human Umbilical Vein Endothelial Cells in Direct Coculture

Bone is an active tissue where bone mineralization and resorption occur simultaneously. In the case of fracture, there are numerous factors required to facilitate bone healing including precursor cells and blood vessels. To evaluate the interaction between bone marrow-derived mesenchymal stem cells (BMSC)—the precursor cells able to differentiate into bone-forming cells and human umbilical vein endothelial cells (HUVEC)—a cell source widely used for the study of blood vessels. We performed direct coculture of BMSC and HUVEC in normoxia and chemically induced hypoxia using Cobalt(II) chloride and Dimethyloxaloylglycine and in the condition where oxygen level was maintained at 1% as well. Cell proliferation was analyzed by crystal violet staining. Osteogenesis was examined by Alizarin Red and Collagen type I staining. Expression of angiogenic factor-vascular endothelial growth factor (VEGF) and endothelial marker-von Willebrand factor (VWF) were demonstrated by immunohistochemistry and enzyme-linked immunosorbent assay. The quantitative polymerase chain reaction was also used to evaluate gene expression. The results showed that coculture in normoxia could retain both osteogenic differentiation and endothelial markers while hypoxic condition limits cell proliferation and osteogenesis but favors the angiogenic function even after 1 of day treatment.

Bone integration in acetabular revision hip arthroplasty using equine-derived bone grafts: a retrospective study

PURPOSE

During the last decade, total hip arthroplasty has become a common procedure performed in young patients, as well as elderly ones. This has led to an increase in total hip arthroplasty revisions. Loosening of primary components with associated bone loss represents the major cause of total hip arthroplasty revision. This study evaluates the safety and performance of an enzyme-deantigenic equine-derived bone graft material in acetabular defect reconstruction.

METHODS

Records of 55 patients who were treated for Paprosky type II or III acetabular bone defects with arthroplasty revisions using equine-derived bone and followed for an average of 34 months (range from 24 to 48 months) were analyzed.

RESULTS

Of the 55 revisions, 49 (89%) were regarded as successful, showing good osteointegration without signs of mobilization. Failures included six cases (11%) of mobilization: five cases of aseptic mobilization (9.1% of revisions, 83% of failures) and one case of septic mobilization (1.9% of revisions, 17% of failures). These results are consistent with those of studies having a similar follow-up period for allografts used in combination with trabecular metal components.

CONCLUSIONS

Results of the present study suggest that enzyme-treated equine-derived bone grafts may be a valid alternative to autogenous and homologous bone grafts in total hip arthroplasty revision.

Comparative Study on the Application of Mesenchymal Stromal Cells Combined with Tricalcium Phosphate Scaffold into Femoral Bone Defects

This prospective study sought to evaluate the healing quality of implanted ultraporous β-tricalcium phosphate sown with expanded autologous mesenchymal stromal cells (MSCs) into femoral defects during revision hip arthroplasty. A total of 37 osseous defects in 37 patients were treated and evaluated concerning bone regeneration. Nineteen subjects received β-tricalcium phosphate graft material serving as a carrier of expanded autologous MSCs (the trial group A), nine subjects received β-tricalcium phosphate graft material only (the study group B) and nine subjects received cancellous allografts only (the control group C). Clinical and radiographic evaluations were scheduled at 6 weeks, 3, 6, and 12 months post-operatively, and performed at the most recent visit as well. All observed complications were recorded during follow-up to assess the use of an ultraporous β-tricalcium phosphate synthetic graft material combined with expanded MSCs in bone defect repair. The resulting data from participants with accomplished follow-up were processed and statistically evaluated with a Freeman–Halton modification of the Fischer’s exact test, a P < 0.05 value was considered to be significant. Whereas no significant difference was observed between the trial group A with β-tricalcium phosphate synthetic graft material serving as a carrier of expanded autologous MSCs and control group C with cancellous impaction allografting in terms of the bone defect healing, significant differences were documented between the study group B with β-tricalcium phosphate graft material only and control group C. Regarding adverse effects, six serious events were recorded during the clinical trial with no causal relationship to the cell product. β-tricalcium phosphate synthetic graft material serving as a carrier of expanded autologous MSCs appears safe and promotes the healing of bone defects in a jeopardized and/or impaired microenvironment. This clinical trial was registered at the EU Clinical Trials Register before patient recruitment (Registration number: EudraCT number 2012-005599-33; Date of registration: 2013-02-04).

In vivo bone regeneration on titanium devices using serum-free grown adipose-derived stem cells, in a sheep femur model

AIM

The aim of this study was to investigate the capacity of adipose-derived stem cells (ADSC), grown in serum-free conditions, to regenerate bone around titanium discs with different titanium surfaces.

MATERIAL AND METHODS

Ovine ADSC (oADSC) were isolated from seven sheep and cultured using serum-free and osteogenic conditions. Prior to in vivo testing, the growth and osteogenic behaviour of these cells were analysed in vitro using cell proliferation and extracellular matrix mineralisation assays. The bone regenerative capacity of autologous oADSC was evaluated in vivo on titanium discs in a sheep femur epicondyle model. Machined (MTi) and alumina-blasted (ABTi) titanium discs were used. Bone regeneration within the defects was evaluated after 1 month using histology and histomorphometry. PKH26 cell-tracking dye was used to verify the persistence of oADSC in the surgical wound.

RESULTS

oADSC sourced from five of seven sheep differentiated into osteoblast-like cells. Cellular proliferation was reduced only for osteogenically induced oADSC (oOS-ADSC) grown on ABTi, compared to non-induced oADSC grown on ABTi and tissue culture polystyrene (P = 0.03 and 0.02 respectively). There was no significant difference for in vitro mineralisation assays comparing oADSC with oOS-ADSC, regardless of implant surface type. oADSC labelled with PKH26 were detected 1 month after surgery within the defect. There was no difference in bone regeneration between the bone defects treated with oADSC vs. just blood clot.

CONCLUSION

After 1-month healing, the use of autologous oADSC did not improve bone regeneration in defects containing titanium devices with different surfaces.

Design and properties of novel gallium-doped injectable apatitic cements

Different possible options were investigated to combine an apatitic calcium phosphate cement with gallium ions, known as bone resorption inhibitors. Gallium can be either chemisorbed onto calcium-deficient apatite or inserted in the structure of β-tricalcium phosphate, and addition of these gallium-doped components into the cement formulation did not significantly affect the main properties of the biomaterial, in terms of injectability and setting time. Under in vitro conditions, the amount of gallium released from the resulting cement pellets was found to be low, but increased in the presence of osteoclastic cells. When implanted in rabbit bone critical defects, a remodeling process of the gallium-doped implant started and an excellent bone interface was observed.

STATEMENT OF SIGNIFICANCE

The integration of drugs and materials is a growing force in the medical industry. The incorporation of pharmaceutical products not only promises to expand the therapeutic scope of biomaterials technology but to design a new generation of true combination products whose therapeutic value stem equally from both the structural attributes of the material and the intrinsic therapy of the drug. In this context, for the first time an injectable calcium phosphate cement containing gallium was designed with properties suitable for practical application as a local delivery system, implantable by minimally invasive surgery. This important and original paper reports the design and in-depth chemical and physical characterization of this groundbreaking technology.

Osteointegration of an Uncemented Modular Revision Stem Implanted during revision Hip Surgery

Background: Though mid-term survival rates of over 95% in several series have been published, there is still a paucity of related literature regarding the role of vertical stem instability in the osteointegration of fluted tapered stems. This paper presents a comprehensive and prospective assessment on short-term experiences with uncemented modular femoral stem in the treatment of defective femur during revision surgery of total hip replacement. Materials and methods: Clinical and radiological monitoring of 20 consecutive patients with implanted tapered fluted revision stem (Lima Corporate, Udine, Italy) was of 27 months in average (20–35 months). The average pre-operative Merle d’Aubigné and Postel method score was 6.3 points (3–10 points). The frequency of femur defects, classified according to Paprosky, was IIIA = 9 and IIIB = 11. Results: During last follow-up, the Merle d’Aubigné and Postel hip score was on average 11.7 (6–16 points). Compared to post-operation radiograph, stem migration of 1.9 mm (0–11 mm) on average was found. This vertical stem migration was observed only when comparing hip radiographs immediately after surgery, and at 6 weeks post-surgery. The Paprosky IIIA defects group, presented a subsided stem by an average of 1.5 mm. In the group of Paprosky IIIB defects, the stem subsidence was on average 2.3 mm. All 20 patients in the study showed excellent osteointegration of the uncemented revision modular stem. Conclusions: This study found and excellent osteointegration of the Lima uncemented tapered fluted revision modular stem in defective femur with a cortical bone segment present in the diaphyseal isthmus area. The initial vertical instability leading to stem migrating during the first six weeks following surgery did not, however, affect its osteointegration.

Treatment of acetabular defects during revision total hip arthroplasty--preliminary clinical and radiological outcome using bone substitute materials

Acetabular defects are a particular challenge during THR revision. Defects may be filled with autologous bone grafts, allografts or synthetic bone substitute materials. In this preliminary, retrospective study, 22 patients were treated with an oval shaped revision cup and a combination of synthetic bone substitute materials, namely hydroxyapatite and beta-tricalcium phosphate. The postoperative outcome was evaluated regarding the functional clinical outcome and quality of life using the Harris hip score, the WOMAC and the SF-36. Signs of loosening and changes of the implant position were evaluated from plain radiographs. Follow up examinations were performed after an average duration of 20.5 months (7-33 months). Postoperatively, we found a significant increase of the Harris hip score, and an increase in both the SF-36 and the WOMAC scores (without statistical significance). No radiographic signs of loosening were evident at the time of follow up. The use of synthetic bone substitute materials offers a possible alternative to the use of autologous and allogenic bone grafts in acetabular revision surgery. Further randomised controlled long-term studies are needed to verify the promising short-term results and to determine potential side effects, such as possible third body wear.

The revision acetabulum – allograft and bone substitutes

A common situation presenting to the orthopaedic surgeon today is a worn acetabular liner with substantial acetabular and pelvic osteolysis. The surgeon has many options for dealing with osteolytic defects. These include allograft, calcium based substitutes, demineralised bone matrix, or combinations of these options with or without addition of platelet rich plasma. To date there are no clinical studies to determine the efficacy of using bone-stimulating materials in osteolytic defects at the time of revision surgery and there are surprisingly few studies demonstrating the clinical efficacy of these treatment options. Even when radiographs appear to demonstrate incorporation of graft material CT studies have shown that incorporation is incomplete. The surgeon, in choosing a graft material for a surgical procedure must take into account the efficacy, safety, cost and convenience of that material.

Cite this article: Bone Joint J 2014;96-B (11 Suppl A):70–2.

The use of a novel bone allograft wash process to generate a biocompatible, mechanically stable and osteoinductive biological scaffold for use in bone tissue engineering

Fresh-frozen biological allograft remains the most effective substitute for the 'gold standard' autograft, sharing many of its osteogenic properties but, conversely, lacking viable osteogenic cells. Tissue engineering offers the opportunity to improve the osseointegration of this material through the addition of mesenchymal stem cells (MSCs). However, the presence of dead, immunogenic and potentially harmful bone marrow could hinder cell adhesion and differentiation, graft augmentation and incorporation, and wash procedures are therefore being utilized to remove the marrow, thereby improving the material's safety. To this end, we assessed the efficiency of a novel wash technique to produce a biocompatible, biological scaffold void of cellular material that was mechanically stable and had osteoinductive potential. The outcomes of our investigations demonstrated the efficient removal of marrow components (~99.6%), resulting in a biocompatible material with conserved biomechanical stability. Additionally, the scaffold was able to induce osteogenic differentiation of MSCs, with increases in osteogenic gene expression observed following extended culture. This study demonstrates the efficiency of the novel wash process and the potential of the resultant biological material to serve as a scaffold in bone allograft tissue engineering.

Clinical experience with computer navigation in revision total hip arthroplasty

The biomechanically and anatomically correct placement of hip prostheses components is the main challenge in revision hip arthroplasty. The orientation of the cup and stem with the restoration of leg length, offset and hip centre is hampered by the defect situations frequently present. In primary hip arthroplasty, it has been demonstrated that the components can be accurately positioned using computer-navigated procedures. However, such procedures could also be of considerable benefit in revision hip arthroplasty. Systems that not only detect anatomical landmarks using pointers but also use image data for referencing may provide a possible solution for the defect situation. Literature about navigation in revision arthroplasty is very rare. This article comprises general considerations on this subject and presents our experience and possible clinical applications.

Application of scaffolds for bone regeneration strategies: current trends and future directions

Scaffolds are extensively used in surgery to replace missing bone and to achieve bony union and fusion. An ideal scaffold should not only maintain, induce, and restore biological functions where cells, extracellular matrix, and growth factors are needed, but also have the right properties with respect to degradation, cell binding, cellular uptake, non-immunogenicity, mechanical strength, and flexibility. Here we examine both the basic science behind the development of scaffolds and comprehensively and systematically review the clinical applications.

Fractures of the acetabulum in elderly patients: an update

The incidence of acetabular fractures in elderly patients is increasing. Poor bone quality and concomitant diseases are the main features of these patients. Fracture patterns are marked by a high degree of variability in terms of patient and fracture characteristics. Preoperative planning with plain radiographs and computed tomography, including 3-dimensional reconstructions, is recommended. Treatment remains challenging because of precarious general health, severe osteopenia, comminution, and associated femoral head damage. Treatment options available include closed management, open reduction with internal fixation, percutaneous fixation in situ, and acute or staged total hip arthroplasty (THA) whether alone or combined with osteosynthesis. In the case of significant destruction of the articular cartilage, primary THA may provide the best solution. Whichever surgical method is chosen, the objective is rapid mobilisation of the patient on a walker or crutches. Late local complications that may occur after nonoperative or operative treatment include posttraumatic arthritis, nonunion, malunion, wound infection, dislocation, intrusive hardware, nerve palsy, and heterotopic bone formation. In this article an overview of the current trends in the management of acetabulum fractures in the elderly is presented.