Reconstruction of periacetabular tumours with saddle prosthesis or custom-made prosthesis, functional results and complications

Biomechanical and clinical outcomes of 3D-printed versus modular hemipelvic prostheses for limb-salvage reconstruction following periacetabular tumor resection: a mid-term retrospective cohort study

BACKGROUND

Debates persist over optimal pelvic girdle reconstruction after acetabular tumor resection, with surgeons grappling between modular and 3D-printed hemipelvic endoprostheses. We hypothesize superior outcomes with 3D-printed versions, yet scarce comparative research exists. This study fills the gap, examining biomechanics and clinical results retrospectively.

METHODS

From February 2017 to June 2021, we retrospectively assessed 32 patients undergoing en bloc resection for malignant periacetabular tumors at a single institution.

PRIMARY OUTCOME

limb function.

SECONDARY OUTCOMES

implant precision, hip joint rotation center restoration, prosthesis-bone osteointegration, and complications. Biomechanical characteristics were evaluated through finite element analysis on pelvic defect models.

RESULTS

In the 3D-printed group, stress distribution mirrored a normal pelvis, contrasting the modular group with elevated overall stress, unstable transitions, and higher stress peaks. The 3D-printed group exhibited superior functional scores (MSTS: 24.3 ± 1.8 vs. 21.8 ± 2.0, p < 0.05; HHS: 79.8 ± 5.2 vs. 75.3 ± 3.5, p < 0.05). Prosthetic-bone interface osteointegration, measured by T-SMART, favored 3D-printed prostheses, but surgery time (426.2 ± 67.0 vs. 301.7 ± 48.6 min, p < 0.05) and blood loss (2121.1 ± 686.8 vs. 1600.0 ± 505.0 ml, p < 0.05) were higher.

CONCLUSIONS

The 3D-printed hemipelvic endoprosthesis offers precise pelvic ring defect matching, superior stress transmission, and function compared to modular endoprostheses. However, complexity, fabrication expertise, and challenging surgical implantation result in prolonged operation times and increased blood loss. A nuanced consideration of functional outcomes, complexity, and patient conditions is crucial for informed treatment decisions.

LEVEL OF EVIDENCE

Level III, therapeutic study (Retrospective comparative study).

Incidence of avascular necrosis of native femur following hip transposition surgery for periacetabular malignancies: a single-centre experience

BACKGROUND

Hip transposition surgery after surgical resection of large pelvic tumours is a well-established alternate to endoprosthetic reconstruction. The major goals of surgery are to ensure adequate resection margins with limb salvation, albeit with acceptable levels of morbidity. While surveillance is aimed at diagnosing local recurrence or distant metastasis primarily, other complications may occasionally be seen.The aim of this study was to assess incidence of avascular necrosis (AVN) in the preserved native femoral heads after hip transposition surgery for periacetabular malignancies, also known as hanging hip surgery.

PATIENTS AND METHODS

Patient records and follow-up imaging of 22 patients who had undergone hanging hip surgery from 1999 to 2020 were retrospectively analysed to assess for any probable causes of AVN.

RESULTS

Of the 22 patients, 5 (22.7%) had developed AVN on follow-up with a mean time of onset of about 10.5 months from surgery (5 months-2 years). A review of the patient demographics, surgical notes, preoperative management did not offer any clues as to the cause of AVN in these patients. Osteopenia was the most common radiological finding (59%) in most patients, but this also did not herald AVN onset.

CONCLUSIONS

The theory that loss of major vascular supply to the femoral head from capsular disruption during hip transposition surgery would lead to AVN in most patients did not hold true as AVN occurred in a small number of patients.

Biomimetic design and clinical application of Ti-6Al-4V lattice hemipelvis prosthesis for pelvic reconstruction

OBJECTIVE

This study aims to biomimetic design a new 3D-printed lattice hemipelvis prosthesis and evaluate its clinical efficiency for pelvic reconstruction following tumor resection, focusing on feasibility, osseointegration, and patient outcomes.

METHODS

From May 2020 to October 2021, twelve patients with pelvic tumors underwent tumor resection and subsequently received 3D-printed lattice hemipelvis prostheses for pelvic reconstruction. The prosthesis was strategically incorporated with lattice structures and solid to optimize mechanical performance and osseointegration. The pore size and porosity were analyzed. Patient outcomes were assessed through a combination of clinical and radiological evaluations.

RESULTS

Multiple pore sizes were observed in irregular porous structures, with a wide distribution range (approximately 300-900 μm). The average follow-up of 34.7 months, ranging 26 from to 43 months. One patient with Ewing sarcoma died of pulmonary metastasis 33 months after surgery while others were alive at the last follow-up. Postoperative radiographs showed that the prosthesis's position was consistent with the preoperative planning. T-SMART images showed that the host bone was in close and tight contact with the prosthesis with no gaps at the interface. The average MSTS score was 21 at the last follow-up, ranging from 18 to 24. There was no complication requiring revision surgery or removal of the 3D-printed hemipelvis prosthesis, such as infection, screw breakage, and prosthesis loosening.

CONCLUSION

The newly designed 3D-printed lattice hemipelvis prosthesis created multiple pore sizes with a wide distribution range and resulted in good osteointegration and favorable limb function.

Design of 3D-printed prostheses for reconstruction of periacetabular bone tumors using topology optimization

Background: Prostheses for the reconstruction of periacetabular bone tumors are prone to instigate stress shielding. The purpose of this study is to design 3D-printed prostheses with topology optimization (TO) for the reconstruction of periacetabular bone tumors and to add porous structures to reduce stress shielding and facilitate integration between prostheses and host bone. Methods: Utilizing patient CT data, we constructed a finite element analysis (FEA) model. Subsequent phases encompassed carrying out TO on the designated area, utilizing the solid isotropic material penalization model (SIMP), and this optimized removal area was replaced with a porous structure. Further analyses included preoperative FEA simulations to comparatively evaluate parameters, including maximum stress, stress distribution, strain energy density (SED), and the relative micromotion of prostheses before and after TO. Furthermore, FEA based on patients' postoperative CT data was conducted again to assess the potential risk of stress shielding subsequent to implantation. Ultimately, preliminary follow-up findings from two patients were documented. Results: In both prostheses, the SED before and after TO increased by 143.61% (from 0.10322 to 0.25145 mJ/mm3) and 35.050% (from 0.30964 to 0.41817 mJ/mm3) respectively, showing significant differences (p < 0.001). The peak stress in the Type II prosthesis decreased by 10.494% (from 77.227 to 69.123 MPa), while there was no significant change in peak stress for the Type I prosthesis. There were no significant changes in stress distribution or the proportion of regions with micromotion less than 28 μm before and after TO for either prosthesis. Postoperative FEA verified results showed that the stress in the pelvis and prostheses remained at relatively low levels. The results of follow-up showed that the patients had successful osseointegration and their MSTS scores at the 12th month after surgery were both 100%. Conclusion: These two types of 3D-printed porous prostheses using TO for periacetabular bone tumor reconstruction offer advantages over traditional prostheses by reducing stress shielding and promoting osseointegration, while maintaining the original stiffness of the prosthesis. Furthermore, in vivo experiments show that these prostheses meet the requirements for daily activities of patients. This study provides a valuable reference for the design of future periacetabular bone tumor reconstruction prostheses.

Custom designed and 3D-printed titanium pelvic implants for acetabular reconstruction after tumour resection

BACKGROUND

Reconstructive procedure following resection of large pelvic tumours around the hip joint remains a complex challenge.

METHODS

This study presents a retrospective case series of patients presenting with benign or malignant pelvic tumour for which an internal hemipelvectomy including the hip joint and subsequent reconstruction with a custom designed 3-dimensional printed titanium pelvic implant (3DPPI) has been performed between August 2013 and January 2018.

RESULTS

15 consecutive patients with a median age of 33.9 years (IQR 26.4-72.2) and a median BMI of 20.7 kg/m2 (IQR 19.0-33.3) were reviewed after median follow-up of 33.8 months (IQR 24.0-78.1). The majority of patients presented with a malignant tumour as their principal diagnosis (n = 13, 86.7%). The median surgical time was 5.5 hours (IQR 4.5-8.5) and median peri-operative blood loss was 5000 ml (IQR 2000-10000). The median MSTS score at follow-up was 63.3% (IQR 51.7-86.7%). The median NRS in rest was 0.0 (IQR 0.0-5.0), the median NRS during activity was 2.0 (IQR 0.5-7.0) and the median HOOS-PS was 76.6% (IQR 67.9-91.0). 4 patients had implant-specific complications (n = 4, 26.6%); 1 hip dislocation (Henderson type 1a), 3 structural complications (type 3a), 1 deep infection (type 4a) and 1 local tumour recurrence (type 5b). At follow-up, 4 out of 15 implants were classified as a failure, resulting in an implant survival rate of 73.3%.

CONCLUSIONS

Acceptable peri-operative outcomes, functional results, complication rates and short-term implant survival can be achieved in a cohort of complex patients undergoing 3DPPI reconstruction after hemipelvectomy including the acetabulum.

What are the 2-year survivorship outcomes of custom hemipelvis reconstruction after hemipelvectomy and revision arthroplasty? The evolution of a custom ilium "monoflange"

BACKGROUND

Innovations in machined and three-dimensionally (3D) printed implant technology have allowed for customized complex pelvic reconstructions. We sought to determine the survivorship of custom hemipelvis reconstruction using ilium-only fixation at a minimum 2-year follow-up, their modes of failure, and the postoperative complications resulting from the procedure.

METHODS

A retrospective review identified 12 consecutive patients treated with custom hemipelvis reconstruction. Indications for surgery were bone tumor requiring internal hemipelvectomy (four patients) or multiply revised, failed hip arthroplasty with massive bone loss (eight patients). All patients had a minimum of 2-year follow-up with a mean of 60.5 months. Kaplan-Meier survivorship analysis was determined for all patients. Postoperative complications and reoperations were categorized for all patients.

RESULTS

At a mean of 60.5 months, 11 of 12 patients had retained their custom implant (92% survivorship). One implant was removed as a result of an acute periprosthetic joint infection (PJI). There were no cases of aseptic loosening. Seven of 12 patients required reoperation (three PJI; two dislocations; two superficial wound complications), with five patients going on to reoperation-free survival.

CONCLUSIONS

Custom hemipelvis reconstruction utilizing an ilium monoflange provides durable short-term fixation at a minimum 2-year follow-up. Reoperation for infection and dislocation is common.

Acetabular reconstruction in oncological surgery: A systematic review and meta-analysis of implant survivorship and patient outcomes

BACKGROUND

Reconstruction of the hip for peri-acetabular oncological disease remains a challenge. The objective of this study was to summarize the evidence and identify techniques utilized for primary and metastatic tumors of the acetabulum and hemipelvis.

METHODS

A systematic review of the published literature was carried out in accordance with PRISMA guidelines. MEDLINE, EMBASE and Cochrane databases identified relevant articles. Quality was assessed using the Newcastle-Ottawa Scale. The study was registered on PROSPERO.

RESULTS

53 papers were included, 16 were suitable for meta-analysis. 909 patients had primary and 1140 metastatic disease. 1094 patients underwent reconstruction with conventional total hip arthroplasty (with or without cup-cage or cement augmentation) or modifications of the Harrington procedure, collectively termed 'non-complex'. 928 patients underwent 'complex' reconstructions with either a modular hemipelvic, saddle, reverse snow-cone, custom-made or 3D-printed endoprosthesis. The most common complication was deep infection (11%) followed by dislocation (5%). Mean MSTS scores were 61.9% for 'non-complex' versus 63.2% for 'complex' reconstruction. Meta-analysis suggested increased mortality for primary (OR 3.14; 95% CI 1.15-8.54) and trends toward reduced mortality for metastatic disease (OR 0.93; 95% CI 0.26-3.29) following 'complex' versus 'non-complex' reconstruction. Reoperation rates were higher following 'complex' reconstruction for metastatic disease (OR 1.90; 95% CI 0.66-5.46) and similar for primary disease (OR 0.98; 95% CI 0.45-2.14).

CONCLUSIONS

Peri-acetabular tumors are associated with high rates of morbidity and mortality. Decisions regarding implant selection are multi-factorial with recent increase in the use of custom-made and 3D-printing technologies. Multiple factors contribute to the oncological outcome and patient function. Further research is required in order to guide optimal practice.

Reconstruction of Bony Defects after Tumor Resection with 3D-Printed Anatomically Conforming Pelvic Prostheses through a Novel Treatment Strategy

There has been an increasing interest and enormous applications in three-dimensional (3D) printing technology and its prosthesis, driving many orthopaedic surgeons to solve the difficult problem of bony defects and explore new ways in surgery approach. However, the most urgent problem is without an effective prosthesis and standard treatment strategy. In order to resolve these problems, this study was performed to explore the use of a 3D-printed anatomically conforming pelvic prosthesis for bony defect reconstruction following tumor resection and to describe a detailed treatment flowchart and the selection of a surgical approach. Six patients aged 48-69 years who had undergone pelvic tumor resection underwent reconstruction using 3D-printed anatomically conforming pelvic prostheses according to individualized bony defects between March 2016 and June 2018. According to the Enneking and Dunham classification, two patients with region I+II tumor involvement underwent reconstruction using the pubic tubercle-anterior superior iliac spine approach and the lateral auxiliary approach and one patient with region II+III and three patients with region I+II+III tumor involvement underwent reconstruction using the pubic tubercle-posterior superior iliac spine approach. The diagnoses were chondrosarcoma and massive osteolysis. After a mean follow-up duration of 30.33 ± 9.89 months (range, 18-42), all patients were alive, without evidence of local recurrence or distant metastases. The average blood loss and blood transfusion volumes during surgery were 2500.00 ± 1461.51 ml (range, 1200-5000) and 2220.00 ± 1277.62 ml (range, 800-4080), respectively. During follow-up, the mean visual analogue scale (VAS) score decreased, and the mean Harris hip score increased. There were no signs of hip dislocation, prosthetic loosening, delayed wound healing, or periprosthetic infection. This preliminary study suggests the clinical effectiveness of 3D-printed anatomically conforming pelvic prostheses to reconstruct bony defects and provide anatomical support for pelvic organs. A new surgical approach that can be used to expose and facilitate the installation of 3D-printed prostheses and a new treatment strategy are presented. Further studies with a longer follow-up duration and larger sample size are needed to confirm these encouraging results.

What are the Complications of Three-dimensionally Printed, Custom-made, Integrative Hemipelvic Endoprostheses in Patients with Primary Malignancies Involving the Acetabulum, and What is the Function of These Patients?

BACKGROUND

Functional reconstruction after resection of pelvic malignancies involving the acetabulum remains challenging. Numerous reconstruction methods have been proposed, but they are generally associated with mechanical and nonmechanical complications. To improve the function of patients with primary malignancies of the acetabulum after internal hemipelvectomy and reduce the complication rate after this procedure, we designed a series of three-dimensionally (3D) printed, custom-made, integrative hemipelvic endoprostheses with a porous structure and wanted to present the early results of using this construct to determine whether it could be considered a reasonable reconstruction option.

QUESTIONS/PURPOSES

We performed this study to (1) evaluate, in a small group of patients, whether the new endoprosthesis restores short-term lower-limb function; (2) identify short-term complications associated with the use of this endoprosthesis; and (3) assess osseointegration between the host bone and the 3D-printed integrative hemipelvic endoprosthesis with a porous structure.

METHODS

Between October 2016 and May 2017, our center treated 26 patients with malignancies involving the acetabulum. Thirteen of these patients received hemipelvic replacement with a 3D-printed, custom-made, integrative endoprosthesis, six received hemipelvic replacement with a modular endoprosthesis, four received radiotherapy, and three received external hemipelvectomy. Resection and reconstruction with a 3D-printed, custom-made, integrative endoprosthesis were indicated if the resection margin was the same as that achieved in hemipelvectomy, if reconstruction would preserve reasonable function after resection, if the patient had a good physical status and life expectancy longer than 6 months, and if the patient was willing to accept the potential risk of a 3D-printed, custom-made, endoprosthesis. The exclusion criteria were an inability to achieve a satisfactory surgical margin with limb salvage, inability to preserve the function of the limb because of tumor involvement of the sacral nerve or sciatic nerve, and unresectable and/or widely metastatic disease on presentation. Pain and function were evaluated with the 10-cm VAS score (range 0 to 10; a lower score is desirable), the 1993 version of the Musculoskeletal Tumor Society (MSTS-93) score (range 0 to 30; a higher score is desirable), and the Harris hip score ([HHS]; range 0 to 100; a higher score is desirable) were evaluated preoperatively and at a median of 27 months after reconstruction (range 24 to 31 months). The functional scores and complications were recorded after reviewing the patients' records. Osseointegration was assessed with digital tomosynthesis by two senior surgeons. We observed the trabecular structures connected to the implant surface to assess whether there was good osseointegration.

RESULTS

The median preoperative VAS score, MSTS-93 score, and HHS were 5 (range 2 to 8), 14 (range 3 to 18), and 64 (range 20 to 76) points, respectively. At the latest follow-up interval, the median VAS score, MSTS-93 score, and HHS were 2 (range 0 to 6), 23 (range 15 to 27), and 82 (range 44 to 93) points, respectively. No deep infection, dislocation, endoprosthetic breakage, aseptic loosening, or local recurrence occurred. Two patients experienced delayed wound healing; the wounds healed after débridement. Using digital tomography, we found that all implants were well-osseointegrated at the final follow-up examination.

CONCLUSIONS

A 3D-printed, custom-made, integrative hemipelvic endoprosthesis provides acceptable early outcomes in patients undergoing pelvic reconstruction. Osseointegration is possible, and we anticipate this will lead to biologic stability with a longer follow-up interval. The custom-made integrative design ensured precise implantation. Although a few patients in this study had only a short follow-up duration, the functional results were reasonable. We have observed no major complications so far, but this was a very small series and we caution that these are large reconstructions that will certainly result in complications for some patients. Our method uses a precise preoperative simulation and endoprosthesis design to aid the surgeon in performing challenging operations. If our early results are confirmed with more patients and longer follow-up and are replicated at other centers, this may be a reconstruction option for patients with periacetabular malignancies.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Three-dimensional-printed custom-made hemipelvic endoprosthesis for primary malignancies involving acetabulum: the design solution and surgical techniques

Background

This study is to describe the detailed design and surgical techniques of three-dimensional (3D)-printed custom-made endoprosthesis for hemipelvic tumorous bone defect.

Methods

According to the pelvic tumor resection classification by Enneking and Dunham, the hemipelvis is divided into three zones including the ilium (P1), acetabulum (P2), and pubis and ischium (P3). Thirteen patients were included in this study. Of these, P1 and P2 were involved in three cases, while P1, P2, and P3 were involved in 10. Based on radiography data, 3D pelvic model was rebuilt, and virtual surgery was simulated. Different fixation methods were applied according to residual bone volume. Parameters of the first sacral (S₁) vestibule, second sacral (S₂) vestibule, the narrowest zone of superior pubic medullary cavity (NPSPMC), and the resected surface of superior pubic medullary cavity (RSSPMC) were selectively measured in various fixation methods. Model overlapping, feature simplifying, and size controlling were three basic steps during design procedure. Volume proportion of porous structure was determined according to estimated weight of resected specimen. Acetabular location, anteversion, and inclination were modulated. Screw diameter, direction, and combination were considered. The osteotomy guides and plastic models were used during surgery.

Results

Of 13 cases, after P1 resection, endoprostheses were fixed to sacra (8; 61.5%), ilia (3; 23.1%), and both (2; 15.4%). After P3 resection, endoprostheses were fixed to residual acetabulum (3; 23.1%), and residual pubis by stem (8; 61.5%) or “cap-like” structure (2; 15.4%). Mean area of the S₁ vestibule, S₂ vestibule, RSSPMC, and PSPMC were 327.9 (222.2 to 400), 131.7 (102.6 to 163.6), 200.5 (103.8 to 333.2), and 79.8 mm² (40.4 to 126.2), respectively. Porous structure with 600 μm pore size and 70% porosity accounted for 68.8% (53.0 to 86.0) of the whole endoprosthesis on average. Mean acetabular anteversion and inclination were designed as 23.2° (20 to 25) and 42.4° (40 to 45). Median numbers of screws designed in the S₁ vestibule was 5 (IQR, 4 to 6), in the S2 vestibule was 1 (IQR, 1 to 2), in the ilium was 5 (IQR, 2 to 6), and in the pubis was 1 (IQR, 1 to 1), while screws designed in the ischium was all 2. Median number of screws inserted in the S₁ vestibule was 4 (IQR, 3 to 4), in the S₂ vestibule was 1 (IQR, 1 to 1), in the ilium was 3 (IQR, 1 to 5), in the pubis was 1 (IQR, 0 to 1), and in the ischium was 1 (IQR, 1 to 1).

Conclusions

This study firstly presents detailed design and related surgical techniques of 3D-printed custom-made hemipelvic endoprosthesis reconstruction. Osseointegration is critical for long-term outcome and requires three design elements including interface connection, porous structure, and initial stability achieved by precise matching and proper fixation methods.

Surgical resection and reconstructive techniques using autologous femoral head bone-grafting in treating partial acetabular defects arising from primary pelvic malignant tumors

Background

The aim of this study is to present and evaluate surgical resection and reconstructive techniques using autologous femoral head bone-grafting in treating partial acetabular defects arising from primary pelvic malignant tumors.

Methods

From January 2009 until January 2015, a total of 20 primary pelvic malignancy cases involving the acetabulum were retrospectively investigated. Surgical resections and reconstructions were conducted based on the type of the tumor with custom osteotomy guides and autologous femoral head bone-grafting. In all cases, prosthesis survival period, complication occurrence, and clinical outcomes data were collected and analyzed.

Results

Thirteen male and 7 female patients with an average age of 48 years old (range 23-69 years old) were followed for a median of 69 months (range 48-112 months). Of these cases, 17 included chondrosarcomas and 3 additional patients with a malignant giant cell tumor of bone (MBGCT) as proven by pathology. During follow-up, 3 cases of chondrosarcoma recurred (15%), of which two cases received hemi-pelvic amputation, 1 case of MBGCT relapsed and developed pulmonary metastases. Two cases of acetabular prosthesis with an impending dislocation received closed reduction followed by 6 weeks of hip abduction brace fixation. One case of prosthesis loosening was revised. In another case a deep infection occurred with debridement and prosthesis removal. Musculoskeletal Tumor Society 1993 (MSTS-93) score was utilized to conduct functional evaluation: 13 cases were good, 6 were average and one was poor.

Conclusion

The precision of the osteotomies performed is likely crucial for this type of reconstructive strategy to be successful. The use of custom guides for acetabular osteotomies and femoral head reconstruction can improve functional outcomes with relatively low complications at the intermediate length of follow-up.

Individual resection and reconstruction of pelvic tumor with three-dimensional printed customized hemi-pelvic prosthesis: A case report

RATIONALE

Pelvic tumor had great impact on patients' quality of life. After tumor resection, how to accurately fill bone defect remained challenging for orthopedic surgeons. Due to lack of individual design, high incidence of prosthetic mismatching, and loosening were reported in pelvic reconstruction surgery with conventional modular prostheses. Nowadays, with rapid development of three-dimensional (3D) print technology, pelvic prostheses could be designed according to patients' own anatomy. The objective of this study was to describe the application of 3D printed customized hemi-pelvic prosthesis for patients with pelvic tumor.

PATIENT CONCERNS

A 62-year-old female had developed severe right joint pain without obvious inducement from 5 months before she sought medical advice. Pain, swelling, and limited range of motion of right joint were founded during physical examination.

DIAGNOSIS

The patients were diagnosed as "right acetabulum metastatic carcinoma" INTERVENTION:: 3D printed titanium alloy hemi-pelvic prosthesis was designed according the morphology of unaffected side hemi-pelvis and subsequently implanted in surgery to reconstruct the pelvis. 3D printed osteotomy guide and pelvic model were also manufactured and applied to improve accuracy of osteotomy and reduce operation time. X-Ray of pelvis, Harris score, musculoskeletal tumor society score (MSTS) and The MOS item short from health survey (SF-36) were recorded during the period of preoperation, 1, 3, 6, 12 months follow-up after operation.

OUTCOMES

3D printed hemi-pelvic prosthesis matched precisely with pelvis and implanted successfully. There was no sign of prosthetic loosening within 12 months' follow-up. No sign of peri-prosthetic infection from laboratory examination. Harris score, MSTS, and SF-36 were gradually increasing during follow-up period.

LESSONS

Satisfactory effect of pelvic reconstruction could be achieved by 3D printed hemi-pelvic prostheses. It also provided a promising way to the treatment of pelvic tumor in similar cases.