Pelvic discontinuity in acetabular revisions: does CT scan overestimate it? A comparative study of diagnostic accuracy of 3D-modeling and traditional 3D CT scan

Mid-Term Clinical and Radiographic Results of Complex Hip Revision Arthroplasty Based on 3D Life-Sized Model: A Prospective Case Series

Background: The pre-operative three-dimensional (3D) assessment of acetabular bone defects may not be evaluated properly with conventional radiographic and computed tomography images. This paper reports mid-term clinical and radiographic outcomes of complex revision total hip arthroplasty (r-THA) based on a 3D life-sized printed model. Methods: Patients who underwent r-THA for septic or aseptic acetabular loosening with acetabular defects Paprosky types IIc, IIIa, and IIIb between 2019 and 2021 were included. The outcomes of the study were to determine clinical and radiographic assessment outcomes at the time of the last follow-up. Results: 25 patients with mean age of 62.9 ± 10.8 (18-83) years old were included. The mean Harris hip score improved from 34.8 ± 8.1 pre-operative to 81.6 ± 10.4 points (p < 0.001). The mean visual analog scale decreased from 6.7 ± 1.4 points pre-operative to 2.4 ± 1.0 points (p < 0.001). The mean limb length discrepancy improved from -2.0 ± 1.2 cm pre-operative to -0.6 ± 0.6 cm (p < 0.001). The mean vertical position of the center of rotation (COR) changed from 3.5 ± 1.7 cm pre-operative to 2.0 ± 0.7 cm (p < 0.05). The mean horizontal COR changed from 3.9 ± 1.5 cm pre-operative to 3.2 ± 0.5 cm (p < 0.05). The mean acetabular component abduction angle changed from 59.7° ± 29.6° pre-operative to 46° ± 3.9 (p < 0.05). Conclusions: A three-dimensional-printed model provides an effective connection between the pre-operative bone defects' evaluation and the intraoperative findings, enabling surgeons to select optimal surgical strategies.

Enhancing Hip Arthroplasty Outcomes: The Multifaceted Advantages, Limitations, and Future Directions of 3D Printing Technology

In the evolving field of orthopedic surgery, the integration of three-dimensional printing (3D printing) has emerged as a transformative technology, particularly in addressing the rising incidence of degenerative joint diseases. The integration of 3D printing technology in hip arthroplasty offers substantial advantages throughout the surgical process. In preoperative planning, 3D models enable meticulous assessments, aiding in accurate implant selection and precise surgical strategies. Intraoperatively, the technology contributes to precise prosthesis design, reducing operation duration, X-ray exposures, and blood loss. Beyond surgery, 3D printing revolutionizes medical equipment production, imaging, and implant design, showcasing benefits such as enhanced osseointegration and reduced stress shielding with titanium cups. Challenges include a higher risk of postoperative infection due to the porous surfaces of 3D-printed implants, technical complexities in the printing process, and the need for skilled manpower. Despite these challenges, the evolving nature of 3D printing technologies underscores the importance of relying on existing orthopedic surgical practices while emphasizing the need for standardized guidelines to fully harness its potential in improving patient care.

Impact of three-dimensional printed planning in Paprosky III acetabular defects: a case-control and cost-comparison analysis

PURPOSE

The main challenges in revision total hip arthroplasty (rTHA) are the treatment of the bone loss and the pre-operative planning. 3D-printed models may enhance pre-operative planning. The aim of the study is to compare the intra- and peri-operative results and costs for Paprosky type 3 rTHAs planned with 3D-printed models to ones accomplished with the conventional imaging techniques (X-rays and CT scan).

METHODS

Seventy-two patients with Paprosky type 3 defect underwent rTHA between 2014 and 2021. Fifty-two patients were treated with standard planning and 20 were planned on 3D-printed models. Surgical time, intra-operative blood loss, number of transfused blood units, number of post-operative days of hospitalization, and use of acetabular rings were compared between the two groups. A costs comparison was also performed.

RESULTS

The 3D-printed group showed reduced operative time (101.8 min (SD 27.7) vs. 146.1 min (SD 49.5), p < 0.001) and total days of hospitalization (9.3 days (SD 3.01) vs. 12.3 days (SD 6.01), p = 0.009). The cost of the procedures was significantly lower than the control group, with an adjusted difference of 4183 euros (p = 0.004). No significant differences were found for the number of total transfused blood units and blood loss and the number of acetabular rings.

CONCLUSION

The use of 3D-printed models led to a meaningful cost saving. The 3D-printed pre-operative planning for complex rTHAs seems to be effective in reducing operating time, hospital stay and overall costs.

Improvement of surgical time and functional results after do-it-yourself 3D-printed model preoperative planning in acetabular defects Paprosky IIA-IIIB

INTRODUCTION

The correct positioning of the implant in revision total hip arthroplasty (rTHA) is critical to obtaining substantial functional outcomes, and to avoiding complications. Current literature supports three-dimensional (3D)-printed models as potentially useful tools for preplanning, as well as the "do it yourself (DIY)" methodology to reduce both the time and costs of this procedure. However, no study has determined the efficacy of both methods combined in a cohort of patients with severe acetabular defects. In the lack of bibliography, we performed rTHA after preoperative planning by DIY-3D-printed models to evaluate its influence in: 1) the surgical time, 2) the functional scores, 3) the intra and postoperative complications, and 4) the reconstruction of the center of rotation (COR) of the hip.

HYPOTHESIS

Preoperative planning through 3D-DIY printed models will both improve the accuracy of the implant positioning, and the surgical time, leading the latter to improved functional scores and reduced complications.

MATERIALS & METHODS

A comparative study of 21 patients with Paprosky IIB to IIIB acetabular defects who underwent rTHA after 3D-printed model preoperative planning by the DIY method between 2016 and 2019 was conducted. A historical cohort of 24 patients served as the comparator. Surgical time, reconstruction of the COR, functional scores, and complications were analyzed.

RESULTS

The mean follow-up was 32.4 (range, 12 to 60) months. All the patients showed significant improvement of the Harris hip score (HHS) after the operation (3D group: 26.58±10.73; control group 22.47±15.43 (p=0.00)). In the 3D-printed model preoperative planning group the mean operation time and the intraoperative complications were significantly lower (156.15±43.03min vs 187.5±54.38min (p=0.045); and 19% vs 62.5% (p=0.003), respectively), and the HHS and patient satisfaction score (PSS) were significantly greater (83.74±8.49 vs 75.59±11.46 (p=0.019); and 8.17±0.88 vs 7.36±1.17 (p=0.023), respectively). No differences were found in the postoperative complications, nor in the restoration of the COR as determined from the acetabular index, verticalization or horizontalization, although the acetabular index was closer to the intended one in the 3D-printed model planning group (46.67°±7.63 vs 49.22±8.1 (p=0.284)).

CONCLUSION

Preoperative planning of severe acetabular defects through 3D-printed models shortens the surgical time, leading to a decrease in complications and thus to better functional outcomes and greater patient satisfaction. Moreover, the DIY philosophy could decrease both the time and costs of traditional 3D planning.

LEVEL OF EVIDENCE

III, retrospective case matched study.

Efficacy of High-Resolution Preoperative 3D Reconstructions for Lesion Localization in Oncological Colorectal Surgery—First Pilot Study

When planning an operation, surgeons usually rely on traditional 2D imaging. Moreover, colon neoplastic lesions are not always easy to locate macroscopically, even during surgery. A 3D virtual model may allow surgeons to localize lesions with more precision and to better visualize the anatomy. In this study, we primary analyzed and discussed the clinical impact of using such 3D models in colorectal surgery. This is a monocentric prospective observational pilot study that includes 14 consecutive patients who presented colorectal lesions with indication for surgical therapy. A staging computed tomography (CT)/magnetic resonance imaging (MRI) scan and a colonoscopy were performed on each patient. The information gained from them was provided to obtain a 3D rendering. The 2D images were shown to the surgeon performing the operation, while the 3D reconstructions were shown to a second surgeon. Both of them had to locate the lesion and describe which procedure they would have performed; we then compared their answers with one another and with the intraoperative and histopathological findings. The lesion localizations based on the 3D models were accurate in 100% of cases, in contrast to conventional 2D CT scans, which could not detect the lesion in two patients (in these cases, lesion localization was based on colonoscopy). The 3D model reconstruction allowed an excellent concordance correlation between the estimated and the actual location of the lesion, allowing the surgeon to correctly plan the procedure with excellent results. Larger clinical studies are certainly required.

Pelvic discontinuity: a challenge to overcome

Pelvic discontinuity (PD) has been a considerable challenge for the hip revision arthroplasty surgeon. However, not all PDs are the same. Some occur during primary cup insertion, resembling a fresh periprosthetic fracture that separates the superior and inferior portions of the pelvis, while others are chronic as a result of gradual acetabular bone loss due to osteolysis and/or acetabular implant loosening.In the past, ORIF, various types of cages, bone grafts and bone cement were utilized with little success. Today, the biomechanics and biology of PD as well as new diagnostic tools and especially a variety of new implants and techniques are available to hip revision surgeons. Ultraporous cups and augments, cup-cage constructs and custom triflange components have revolutionized the treatment of PD when used in various combinations with ORIF and bone grafts. For chronic PD the cup-cage construct is the most popular method of reconstruction with good medium-term results.Dislocation continues to be the leading cause of failure in all situations, followed by infection. Ultimately, surgeons today have a big enough armamentarium to select the best treatment approach. Case individualization, personal experience and improvisation are the best assets to drive treatment decisions and strategies. Cite this article: EFORT Open Rev 2021;6:459-471. DOI: 10.1302/2058-5241.6.210022.

Decision/therapeutic algorithm for acetabular revisions

Background and aim:

Paprosky’s classification is currently the most used classification for periacetabular bone defects but its validity and reliability are widely discussed in literature. Aim of this study was to introduce a new CT-based Acetabular Revision Algorithm (CT-ARA) and to evaluate its validity. The CT-ARA is based on the integrity of five anatomical structures that support the acetabulum. Classification’s groups are defined by the deficiency of one or more of these structures, treatment is based on those groups.

Methods:

In 105 patients the validity of the CT-ARA was retrospectively evaluated using preoperative X-rays, CT-scan and surgery reports. The surgical indications suggested by Paprosky’s algorithm and by CT-ARA were compared with the final surgical technique. Patients were divided into two groups according to time of surgery.

Results:

We reported concordance of indications in 56,2% of cases with the Paprosky’s algorithm and in 63,8% of cases with the CT-ARA. Analysing only the most recent surgeries (group 2), we reported even higher difference of concordance (67,3% Paprosky’s algorithm and 83,7% CT-ARA). The concordance of the CT-ARA among Group 1 and Group 2 resulted significantly different.

Conclusions:

the CT-ARA may be a useful tool for the preoperative decision-making process and showed more correlation with performed surgery compared to the Paprosky’s algorithm.

Histological evaluation of acetabular bone quality during revision hip arthroplasty

PURPOSE

Aim of this study was to evaluate acetabular bone vitality during revision hip arthroplasty and to compare the bone quality between revision and primary acetabular arthroplasty.

METHODS

During primary and revision total hip arthroplasty surgeries, biopsies were taken from the acetabulum after reaming. The samples (osteochondral cylinders of approximately ⩽1 cm long and 3 mm thickness), after removing the mineral component, were cut longitudinally with a thickness section of 5 µm and colored with hematoxylin-eosin dichromic dye and then evaluated histologically by optical microscopy with 40× magnification. Preoperative radiographs were evaluated.

RESULTS

According to inclusion and exclusion criteria, 14 patients formed the revision group patients (mean age: 67.9 years, average time before revision 8.8 years, SD ± 7.06) and 5 patients formed the control primary group (mean age: 61.4 years). The bone quality of the revision group was generally poorer than the primary group, while similar vitality and bone quality has been found between septic and aseptic group. Variables such as age, gender and BMI did not significantly contribute to define bone quality classes.

CONCLUSIONS

The study confirms the differences in quality and bone vitality between cases and controls and the necessity to find strategies to improve the osteointegrative processes in revision arthroplasties.

Application of 3D Printing in Hip and Knee Arthroplasty: A Narrative Review

INTRODUCTION

Ideal surgical positioning and placement of implants during arthroplasty are crucial for long-term survival and optimal functional outcomes. Inadequate bone stock or defects, and anatomical variations can influence the outcomes. Three-dimensional printing (3DP) is an evolving technology that could provide patient-specific instrumentation and implants for arthroplasty, taking into account anatomical variations and defects. However, its application in this field is still not adequately studied and described. The present review was conceptualised to assess the practicality, the pros and cons and the current status of usage of 3DP in the field of hip and knee arthroplasties and joint reconstruction surgeries.

METHODS

A PubMed database search was conducted and a total number of 135 hits were obtained, out of which only 30 articles were relevant. These 30 studies were assessed to obtain the qualitative evidence of the applicability and the current status of 3D printing in arthroplasty.

RESULTS

Currently, 3DP is used for preoperative planning with 3D models, to assess bone defects and anatomy, to determine the appropriate cuts and to develop patient-specific instrumentation and implants (cages, liners, tibial base plates, femoral stem). Its models can be used for teaching and training young surgeons, as well as patient education regarding the surgical complexities. The outcomes of using customised instrumentations and implants have been promising and 3D printing can evolve into routine practice in the years to come.

CONCLUSION

3D printing in arthroplasty is an evolving field with promising results; however, current evidence is insufficient to determine significant advantages that can be termed cost effective and readily available.

Use of 3D modelling and 3D printing for the diagnostic process, decision making and preoperative planning of periprosthetic acetabular fractures

Periprosthetic acetabular fractures represent an uncommon but challenging complication of total hip arthroplasty (THA), mostly related to low-energy trauma and pathological conditions that reduce bone quality. Therefore, particularly in elderly patients, these fractures are associated with periprosthetic osteolysis and bone loss. CT scan is considered the gold standard to define the fracture pattern; however, the presence of the prosthetic implants in situ limits the full view of the articular surface and bone loss. A three-dimensional (3D) modelling software allows precise tridimensional reconstructions of the bony surface, virtually removing the metallic implants trough DICOM image segmentation. We highlight the case of a periprosthetic acetabular fracture around THA which occurred to a 75-year-old woman, in which a 3D modelling software was used to improve the assessment of fracture morphology and bone quality. Moreover, the 3D images were printed in a real-life size model and were used for preoperative implant templating, sizing and surgical simulation.

A New Diagnostic Approach for Periprosthetic Acetabular Fractures Based on 3D Modeling: A Study Protocol

Periprosthetic acetabular fractures after total hip arthroplasty (THA) are mostly related to low energy trauma reduced bone quality. CT-scan is widely used to evaluate acetabular fractures, however, metal artifacts produced prosthetic implants limit the visualization of the articular surface and bone loss assessment. 3D modeling software allows us to creating tridimensional images of the bony surface, removing the metallic implants trough image segmentation. We highlight the use of 3D modeling and rapid prototyping (3D printing) for the diagnostic process of periprosthetic acetabular fracture around THA. 3D modeling software was used to improve the assessment of fracture morphology and bone quality. Moreover, the 3D images were printed in a real-life size model and used for preoperative implant templating, sizing and surgical simulation.