Ice-cream cone reconstruction of the pelvis: a new type of pelvic replacement

Outcomes Following Pedestal Cup Reconstruction of (Impending) Pathological Fractures of the Acetabulum due to Metastatic Bone Disease

Management of periacetabular metastatic bone disease (MBD) is challenging, specifically if associated with bone loss or fracture. The aim of this study was to evaluate the complications and outcomes after undergoing peri-acetabular reconstruction using an 'ice-cream cone' pedestal cup endoprostheses for the most severe cases of (impending) pathological acetabular fractures. Fifty cases with severe periacetabular disease were identified. Acetabular defects were classified using the Metastatic Acetabular Classification (MAC). Pre- and post-operative mobility was assessed using the Eastern Cooperative Oncology Group (ECOG) Performance Status. Pain levels were assessed using a verbal rating scale. Surgical complications and patient survival were analysed; the Prognostic Immune Nutritional Index (PINI) was applied retrospectively to survival. There were 32 females and 18 males with a median age of 65 (41-88). Median post-operative follow-up was 16 months (IQR 5.5-28.5 months). Thirty-nine had complete, and 11, impending pathological fractures. The observed five-year survival was 19%, with a median survival of 16 months (IQR 5.8-42.5 months). Significantly worse survival was observed with PINI scores < 3.0 (p = 0.003). Excluding three perioperative deaths, 13 complications occurred in 12 patients: Implant failure in six patients (four aseptic loosening, one dislocation and one infection). At the final follow-up, mobility and pain levels were improved in 85% and 100%, respectively. Reconstruction of significant pelvic MBD with the 'ice-cream cone' reduces pain and improves mobility. Whilst the mortality rate is high, it remains a reasonable option for bed-bound, immobile patients. We advocate the use of an 'ice-cream cone' prosthesis for selected patients balancing the reported risks with the observed benefits.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13193-024-01917-x.

LUMiC Endoprosthetic Reconstruction of Periacetabular Tumor Defects: A Multicenter Follow-up Study

BACKGROUND

We previously reported promising early results for periacetabular tumor reconstructions using the LUMiC prosthesis. The current study evaluates mid-term complications, revision rates, cumulative incidence of implant revision, and risk factors for complications in a multicenter cohort.

METHODS

We assessed patients in whom a tumor defect after type P1b+2, P2, P2+3, or P1b+2+3 internal hemipelvectomy was reconstructed with a LUMiC prosthesis during the period of 2008 to 2022. Complications were reported according to the Henderson classification. Competing risks models were used to estimate the cumulative incidence of implant revision for mechanical and nonmechanical reasons, and reoperations for any complication. Cox models were used to study the effect of risk factors on dislocation and infection.

RESULTS

One hundred and sixty-six patients (median follow-up, 4.2 years [interquartile range, 2.6 to 7.6 years]) were included. A total of 114 (69%) were treated for a primary malignant tumor, 46 (28%) for metastatic carcinoma, 5 (3%) for a benign aggressive lesion, and 1 (1%) for another reason. One hundred and sixty-five reoperations were performed in 82 (49%) of the patients; 104 (63%) of the reoperations were within 6 months. Thirty-two (19%) of 166 implants were revised: 13 (8%) for mechanical reasons, mainly dislocation (n = 5, 3%), and 19 (11%) for nonmechanical reasons, mainly periprosthetic joint infection (PJI) (n = 15, 9%). The cumulative incidences of revision for mechanical reasons and PJI (Henderson 1 to 4) at 2, 5, and 10 years were 11% (95% confidence interval [CI], 7% to 17%), 18% (12% to 25%), and 24% (16% to 33%), respectively. Previous surgery at the same site was associated with an increased dislocation risk (cause-specific hazard ratio [HRCS], 3.0 [95% CI, 1.5 to 6.4]; p < 0.01), and resections involving the P3 region were associated with an increased infection risk (HRCS, 2.5 [95% CI, 1.4 to 4.7]; p < 0.01).

CONCLUSIONS

Despite a substantial reoperation risk, the LUMiC prosthesis demonstrated its durability in the mid-term, with a low mechanical revision rate and most patients retaining their primary implant. Most complications occur in the first postoperative months. Patients with previous surgery at the same site had an increased dislocation risk and might benefit from more conservative rehabilitation and aftercare. Measures should be aimed at reducing the PJI risk, especially in resections involving the P3 region.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

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.

Clinical outcomes in patients with neurological disorders following periacetabular tumor removal and endoprosthetic reconstruction of the hemipelvis

Background

Surgical treatment of musculoskeletal tumors in the periacetabular region present extremely difficult due to the complex anatomy and need for reconstruction. Orthopedic surgeons face more difficulties in patients with neurological conditions, which can cause increased muscle tone, an elevated risk of fractures, and compromised bone quality. There is limited evidence regarding endoprosthetic reconstruction for periacetabular tumors in individuals with neurological disorders.

Methods

We conducted a single-center retrospective study to examine the outcomes of patients with preexisting neurological conditions who underwent surgery to remove periacetabular tumors and who underwent endoprosthesis reconstruction. Clinical presentation, detailed neurological conditions, complications, and functional outcomes were studied.

Results

Sixteen out of the 838 patients were identified (1.91%), with a mean follow-up time of 33 months. The primary neurological conditions encompassed Parkinson's disease, Alzheimer's disease, dementia, and cerebral ischemic stroke. Every patient was diagnosed with periacetabular lesions that were either primary or oligometastatic. They underwent tumor resection and subsequently received endoprosthetic reconstruction of the hemipelvis. Three patients developed metastasis lesions later, and two patients experienced tumor recurrence. Five cases experienced hip dislocation-one with periprosthetic fracture and one with surgical site infection. The position of the prosthetic rotating center was not correlated with dislocation. The reoperation rate was 31.25%. The cohort of patients all presented with more extended hospital stays and rehabilitation. In 3 patients, the general functional score was good, while in 6 patients, it was fair; in 7 patients, it was regarded as poor. The average MSTS93 score was 49.71%.

Conclusion

Endoprosthetic reconstruction after periacetabular tumor resection is an effective way to eliminate tumors and salvage limbs. However, this group of patients has an increased likelihood of secondary surgery, complications, extended hospital stay, and no significant improvement in functional outcomes. Despite the diverse nature of the cohort, it is recommended to consider enhanced soft tissue reconstruction, supervised functional recovery and rehabilitation training.

Limb Salvage and Pelvic Reconstruction With Endoprosthesis After Pelvic Tumor Resection: A Narrative Review

Periacetabular defects following tumor resection present formidable challenges in reconstruction and continue to pose clinical difficulties. Historically, treatment approaches leaned towards hindquarter amputation; however, due to associated morbidities and functional limitations, limb-sparing procedures gained prominence in the 1980s. Nevertheless, the intricacies of pelvic anatomy and the imperative of achieving wide surgical margins while preserving essential structures make pelvic tumor resection and subsequent reconstruction inherently complex. Various reconstruction modalities have been explored, including non-vascularized fibular grafts and prosthetic implants. Among these options, the LUMiC® endoprosthesis stands out as a promising solution for pelvic reconstruction post-tumor resection. Characterized by a modular design featuring a hydroxyapatite-coated stem and acetabular cup, this device has shown favorable implant survival rates in studies, despite encountering complications primarily associated with soft tissue failure, dislocation, and infection. Notably, the incidence of complications varies across studies. The Henderson classification system delineates these complications, encompassing soft tissue issues, aseptic loosening, periprosthetic fractures, infections, and tumor recurrence. Despite the encouraging functional outcomes associated with the LUMiC® endoprosthesis, it is not immune to limitations. Concerns persist regarding complications such as dislocation and infection, underscoring the imperative for further research to evaluate the long-term durability and reliability of this reconstructive approach. Moreover, advancements in surgical techniques, perioperative management, and the advent of navigation-assisted procedures hold promise for enhancing outcomes and mitigating complication rates in pelvic reconstruction surgeries.

Acetabular Revision with McMinn Cup: Development and Application of a Patient-Specific Targeting Device

BACKGROUND

Surgeries of severe periacetabular bone defects (Paprosky ≥ 2B) are a major challenge in current practice. Although solutions are available for this serious clinical problem, they all have their disadvantages as well as their advantages. An alternative method of reconstructing such extensive defects was the use of a cup with a stem to solve these revision situations. As the instrumentation offered is typically designed for scenarios where a significant bone defect is not present, our unique technique has been developed for implantation in cases where reference points are missing. Our hypothesis was that a targeting device designed based on the CT scan of a patient's pelvis could facilitate the safe insertion of the guiding wire.

METHODS

Briefly, our surgical solution consists of a two-step operation. If periacetabular bone loss was found to be more significant during revision surgery, all implants were removed, and two titanium marker screws in the anterior iliac crest were percutaneously inserted. Next, by applying the metal artifact removal (MAR) algorithm, a CT scan of the pelvis was performed. Based on that, the dimensions and positioning of the cup to be inserted were determined, and a patient-specific 3D printed targeting device made of biocompatible material was created to safely insert the guidewire, which is essential to the implantation process.

RESULTS

In this study, medical, engineering, and technical tasks related to the design, the surgical technique, and experiences from 17 surgical cases between February 2018 and July 2021 are reported. There were no surgical complications in any cases. The implant had to be removed due to septic reasons (independently from the technique) in a single case, consistent with the septic statistics for this type of surgery. There was not any perforation of the linea terminalis of the pelvis due to the guiding method. The wound healing of patients was uneventful, and the implant was fixed securely. Following rehabilitation, the joints were able to bear weight again. After one to four years of follow-up, the patient satisfaction level was high, and the gait function of the patients improved a lot in all cases.

CONCLUSIONS

Our results show that CT-based virtual surgical planning and, based on it, the use of a patient-specific 3D printed aiming device is a reliable method for major hip surgeries with significant bone loss. This technique has also made it possible to perform these operations with minimal X-ray exposure.

Pelvic bone sarcomas, prognostic factors, and treatment: A narrative review of the literature

Primary sarcomas of bone are rare malignant mesenchymal tumors. The most common bone sarcomas are osteosarcoma, Ewing's sarcoma, and chondrosarcoma. The prognosis has improved over the years, but bone sarcomas are still life-threatening tumors that need a multidisciplinary approach for diagnosis and treatment. Bone sarcomas arising in the pelvis present a unique challenge to orthopedic oncologists due to the absence of natural anatomical barriers, the close proximity of vital neurovascular structures, and the high mechanical demands placed on any pelvic reconstruction following the excision of the tumor. While radiotherapy has an important role especially in Ewing's sarcoma and chemotherapy for both Ewing's sarcoma and osteosarcoma, surgery remains the main choice of treatment for all three entities. While external hemipelvectomy has remained one option, the main aim of surgery is limb salvage. After complete tumor resection, the bone defect needs to be reconstructed. Possibilities to reconstruct the defect include prosthetic or biological reconstruction. The method of reconstruction is dependent on the location of tumor and the surgery required for its removal. The aim of this article is to give an insight into pelvic bone sarcomas, their oncological and surgical outcomes, and the options for treatment based on the authors' experiences.

Chondrosarcoma: A Clinical Review

Chondrosarcomas are a diverse group of malignant cartilaginous matrix-producing neoplasms. Conventional chondrosarcomas are a continuum of disease based on the biologic activity of the tumor. The tumors range from the relatively biologically benign low-grade tumors or intermediate atypical cartilaginous tumors (ACTs), to malignant, aggressive high-grade tumors. The clinical presentation, radiographic and pathologic findings, treatments and outcomes vary significantly based on the histologic grade of the tumor. Chondrosarcomas present a diagnostic dilemma, particularly in the differentiation between high- and intermediate-grade tumors and that of low-grade tumors from benign enchondromas. A multidisciplinary team at a tertiary sarcoma centre allows for optimal care of these patients.

LUMiC® endoprosthesis for pelvic reconstruction: A Canadian experience

BACKGROUND AND OBJECTIVES

The LUMiC® prosthesis was introduced to reduce the mechanical complications encountered with periacetabular reconstruction after pelvic tumor resection. Few have evaluated the outcomes associated with its use.

METHODS

A retrospective study from five Orthopedic Oncology Canadian centers was conducted. All patients with a LUMiC® endoprosthesis were included. Their charts were reviewed for surgical and functional outcomes.

RESULTS

A total of 16 patients were followed for 28 months (3-60). A total of 12 patients (75%) had a LUMiC® after a resection of a primary sarcoma. Mean surgical time was 555 min. Four patients (25%) had a two-stages procedure. MSTS score was 60.3 preoperatively and 54.3 postoperatively. Patients got a dual mobility bearing and the silver coated implant was used in 7 patients (43.7%). Five patients (31.3%) underwent capsular reconstruction using a fabric. Silver-coating was not found to reduce infection risk (p = 0.61) and capsuloplasty did not prevent dislocation (p = 0.6). Five patients had peroperative complications (31.3%). Eight patients (50%) had an infection including all four with two-stages surgery. Dislocation occurred in five patients (31.3%) whereas no cases of aseptic loosening were reported. A total of 10 patients (62.5%) needed a reoperation.

CONCLUSION

LUMiC® endoprosthesis provides low rates of aseptic loosening on medium-term follow-up. Infection and dislocation are common complications but we were unable to show benefits of capsuloplasty and silver-coated implants.

Porous tantalum acetabular cups for reconstructions after peri-acetabular resections of primary bone tumours

INTRODUCTION

Periacetabular reconstruction after resection of primary bone tumour is a very demanding procedure. They are frequently associated with scarce functional results and a high rate of complications. We report a series of patients with periacetabular resections for primary bone tumours and reconstruction with a porous tantalum (PT) acetabular cup (AC).

MATERIALS AND METHODS

27 patients (median age 30 years) were included, being affected by primary bone tumours of the pelvis and treated with peri-acetabular resection and reconstruction with a PT AC. The diagnoses were 13 osteosarcomas, 7 chondrosarcomas and 7 Ewing sarcomas. Function was assessed with the Harris Hip Score and complications were classified according to Zeifang.

RESULTS

The median follow-up was 70 months. 1 patient required removal of the PT AC because of implant associated infection 55 months after surgery. There was 1 hip dislocation and no case of aseptic loosening. At final follow-up, the median HHS was 81 points (range 48-92).

CONCLUSIONS

The used PT AC had good medium-term survival rates and good functional results. This technique is a viable reconstructive option after resections of periacetabular primary bone sarcomas.

Risk factor investigation for hip dislocation after periacetabular tumour resection and endoprosthetic reconstruction via thin-slice CT-based 3D model

AIMS

Dislocation of the hip remains a major complication after periacetabular tumour resection and endoprosthetic reconstruction. The position of the acetabular component is an important modifiable factor for surgeons in determining the risk of postoperative dislocation. We investigated the significance of horizontal, vertical, and sagittal displacement of the hip centre of rotation (COR) on postoperative dislocation using a CT-based 3D model, as well as other potential risk factors for dislocation.

METHODS

A total of 122 patients who underwent reconstruction following resection of periacetabular tumour between January 2011 and January 2020 were studied. The risk factors for dislocation were investigated with univariate and multivariate logistic regression analysis on patient-specific, resection-specific, and reconstruction-specific variables.

RESULTS

The dislocation rate was 13.9% (n = 17). The hip COR was found to be significantly shifted anteriorly and inferiorly in most patients in the dislocation group compared with the non-dislocation group. Three independent risk factors were found to be related to dislocation: resection of gluteus medius (odds ratio (OR) 3.68 (95% confidence interval (CI) 1.24 to 19.70); p = 0.039), vertical shift of COR > 18 mm (OR 24.8 (95% CI 6.23 to 128.00); p = 0.001), and sagittal shift of COR > 20 mm (OR 6.22 (95% CI 1.33 to 32.2); p = 0.026).

CONCLUSION

Among the 17 patients who dislocated, 70.3% (n = 12) were anterior dislocations. Three independent risk factors were identified, suggesting the importance of proper restoration of the COR and the role of the gluteus medius in maintaining hip joint stability.Cite this article: Bone Joint J 2022;104-B(10):1180-1188.

Long-term functional recovery in patients with custom-made 3D-printed anatomical pelvic prostheses following bone tumor excision

BACKGROUND

Anatomical custom-made prostheses make it possible to reconstruct complicated bone defects following excision of bone tumors, thanks to 3D-printed technology. To date, clinical measures have been used to report clinical-functional outcome and provide evidence for the effectiveness of this new surgical approach. However, there are no studies that quantified the achievable recovery during common activities by using instrumental clinical-functional evaluation in these patients.

RESEARCH QUESTION

What is the motor performance, functional outcome and quality of life in patients with custom-made 3D-printed pelvic prostheses following bone tumor?

METHODS

To analyze motor performance, six patients performed motion analysis during five motor activities at follow-up of 32 ± 18 months. Joint angles, ground reaction forces and joint moments of the operated and contralateral limbs were compared. On-off activity of lower-limb muscles were calculated from electromyography and compared to a healthy matched population. To analyze functional outcome and quality of life, differences in measured hip abductor strength between limbs were evaluated, as well as clinical-functional scores (Harris Hip Score, Barthel Index, Musculoskeletal Tumor Society score), and quality of life (SF-36 health survey).

RESULTS

We found only slight differences in joint kinematics when comparing operated and contralateral limb. The activity of gluteal muscles was normal, while hamstrings showed out-of-phase activities. Ground reaction forces and hip moments showed asymmetries between limbs, particularly in more demanding motor activities. We found a mean difference in hip abductor strength of 48 ± 82 N between limbs, good clinical-functional scores, and quality of life scores within normative.

SIGNIFICANCE

Our study showed optimal long-term results in functional recovery, mainly achieved through recovery of the gluteal function, although minor impairments were found, which may be considered for future improvement of this innovative surgery. The effect of a more loaded contralateral limb on internal loads and long-term performance of the implant remains unknown and deserves further investigation.

Combined and Modified Gibson and Ilioinguinal Approaches in Type II + III Internal Hemipelvectomy for Periacetabular Tumors

Background

The routine iliofemoral approach and its modifications in type II+III resection require extensive skin incision and massive periacetabular muscle detachment, leading to prolonged hospital stay, increased complication incidence, and impaired lower limb function. Under the management of an enhanced recovery after surgery (ERAS) protocol, a combined and modified Gibson and ilioinguinal (MGMII) approach was used to avoid unnecessary soft tissue trauma during tumor resection and therefore advantageous to patients’ return to normal life.

Methods

Twenty-five patients with type II + III (including type II) periacetabular tumors who underwent reconstruction with 3D printed customized endoprostheses at our center between January 2017 and March 2019 were included in this study. There were 13 cases using MGMII approach and 12 cases using iliofemoral approach. The operation duration and blood loss were assessed by chart review. The surgical margin was evaluated by the histopathological studies. The reconstruction accuracy, the abductor muscle strength, the 1993 version of the Musculoskeletal Tumor Society (MSTS-93), the Harris Hip scores (HHS), and the limp score were evaluated. Complications were recorded after reviewing the patients’ records.

Results

The operative duration and blood loss in MGMII group were shorter than those in the iliofemoral group, but the postoperative hemoglobin was slightly higher than that in the iliofemoral group. The MGMII group had stronger postoperative hip abductors, better functional restoration, and relatively fewer patients with higher limp scores. No complication was observed in the MGMII group. In the iliofemoral group, three patients encountered wound healing delay, and one patient suffered deep infection.

Conclusions

The MGMII approach can better expose the posterior column of the acetabulum, especially the ischial tuberosity, which is beneficial for avoiding tumor rupture during resection. The MGMII approach also helps to preserve residual muscle function, such as the origin of the gluteus medius, while ensuring the extent of resection.

Reconstruction of Type I-II Internal Hemipelvectomy in a Patient With Pelvic Myxoid Chondrosarcoma: A Case Report

Pelvic chondrosarcomas are a major clinical challenge since the only therapeutic approach available is surgical resection. Reconstruction after partial resection of the pelvis including the acetabulum or the hip joint is a laborious and rigorous surgical procedure. Numerous complications are associated with different reparative methods. Moreover, due to the anatomical complexities of the area, adequate surgical margins are difficult to achieve in many cases, which are closely related to the advent of local recurrence of the tumor. Several techniques for hip function restoration and skeletal reconstruction have been reported. The purpose of this report is to describe a novel pelvic reconstruction technique for PI-II resection that required a custom-designed implant. We present the case of a 61-year-old female patient with chronic pain in the gluteal region. The pelvis’s magnetic resonance imaging (MRI) showed an osteolytic tumor in the right iliac wing that compromises the acetabular roof. The diagnosis was a grade 2 central chondrosarcoma. Surgery included the reconstruction of the acetabulum by inserting two Schanz pins coated with hydroxyapatite, one in the iliopubic corridor and the other in the ischium. A supporting “pyramid” was built, unitizing both Schanz with cement, onto which an acetabular cage was inserted. The procedure was completed with a conventional total hip prosthesis. The patient presented an acute prosthesis infection, which positively responded to prompt surgical lavage and antibiotic treatment. After 10 months of follow-up, the patient remains free of infection, with weight-bearing as tolerated, without pain, and with excellent hip motion. No tumor recurrence has occurred. Medialization of the construct has occurred as expected, with no evidence of implant loosening. The technique used in this patient is novel, could be considered cost-effective, and has allowed the reconstruction of a functional hip. For resections of the acetabular area and preservation of the ischium and pelvic zones, this technique may be an acceptable option.

Reconstruction with a cage outlives patients with metastatic disease involving the acetabulum

AIM

The aim of this study was to determine whether patients treated with a caged reconstruction for metastatic acetabular disease would have a construct survival superior to that of their life expectancy.

PATIENTS AND METHODS

We undertook a retrospective study, in a single centre in the United Kingdom, reviewing outcomes for 19 patients (20 hips) treated with a cage reconstruction for metastatic disease of their acetabulum over 6 years. Inclusion criteria were those with an impending fracture of the acetabulum, metastatic dissociation, fracture of the acetabulum and or femur and those whose life expectancy was considered by the oncology team to be >6 months.

RESULTS

In all patients the Restoration GAP II acetabular cage (Stryker, Howmedica Osteonics Corp, NJ, USA) was used in conjunction with a cemented acetabular cup and cemented femoral stem. The mean age at the time of surgery was 68 (44-87) years with breast cancer being the most common primary malignancy (31%) followed by prostate cancer (26%).Radiological survivorship estimates were 94.1% (95% CI, 99.2-65.0) at 12 and 24 months, 70.6% (95% CI, 93.6-16.0) at 36 months and 35.3% (95% CI, 78.2-1.2) at 48 months. There were 3 radiological failures of the implant due to disease progression. Complications occurred in 3 patients with 2 developing deep infection which was treated with suppressive antibiotic therapy following aspiration of the hip. 1 patient suffered a hip dislocation following trauma which was successfully reduced closed and no further intervention was required.

CONCLUSIONS

This study represents the first published case series of the use of the GAP II cage in patients with metastatic acetabular disease. The construct generally outlives the patient and hence is suitable for the treatment of acetabular metastases.

The Harrington Plus Reconstruction for Pelvic and Acetabular Metastases

•

The Harrington Plus reconstruction is a modification of the original Harrington rod technique for reconstruction of extensive periacetabular metastases. This procedure was developed in our institution.

•

An intrapelvic suprapectineal plate is used, with the aim of reconstructing a disrupted anterior column and reducing the risk of failure in cases where there is extensive medial bone loss.

•

This paper describes the outcomes of patients who have undergone this procedure to date.

Background

Surgical management of periacetabular bone metastases is challenging. The Harrington Plus reconstruction is a modification of the original Harrington rod technique. An intrapelvic suprapectineal plate is used, with the aim of reconstructing a disrupted anterior column and reducing the risk of failure in cases where there is extensive medial bone loss.

Methods

A retrospective review of the 13 patients who have undergone the Harrington Plus procedure to date was performed. Mobility status, EQ5D and Oxford Hip scores were assessed.

Results

There was a significant improvement in mobility status, EQ5D and Oxford Hip Scores at 6 months postoperatively (p < 0.05). Two patients returned to theatre for debridement of infection. There were no postoperative dislocations, cup medialisation or cases of loosening of the prosthesis. No patient required revision arthroplasty surgery.

Conclusion

The Harrington Plus procedure produces a reliable construct that allows patients with extensive periacetabular metastatic defects to fully weight-bear. Careful patient selection and multidisciplinary management is essential.

Extra-articular resection of the hip joint for pelvic sarcomas: Are there any oncological and functional risks compared with intra-articular resection?

BACKGROUND

While extra-articular resection (EAR) of the knee and shoulder joint is associated with poorer clinical outcomes, the oncological and functional risks of EAR of the hip joint are unknown. We aimed to compare these risks between EAR of the hip joint and intra-articular resection (IAR).

METHODS

We conducted a comparative study of 75 patients who underwent en-bloc tumour resection and limb-salvage reconstruction for bone sarcomas of the peri-acetabulum between 1996 and 2016. We divided patients into two groups for analyses; EAR (n = 21) and IAR (n = 54).

RESULTS

There was no statistical difference in oncological outcomes; the 5-year cumulative incidence of disease-specific death was 34% and 35% in the EAR and IAR groups, respectively (p = 0.943), and the 5-year cumulative incidence of LR was 26% and 34%, respectively (p = 0.482). The most common complications were dislocation (28%) and deep infection (28%); there was equally no difference between the groups. The mean Musculoskeletal Tumour Society score was 66% and 65% in the EAR and IAR groups, respectively (p = 0.795), and were significantly lower in patients with deep infection (52% vs. 69%; p = 0.013). In a sub-analysis on the outcomes in patients who underwent PI-uninvolved PII-resection for chondrosarcoma, no major differences in oncologic and functional outcomes were confirmed.

CONCLUSION

Patients undergoing EAR and limb-salvage reconstructions of the hip joint have undistinguishable oncological, clinical and functional outcomes compared to those undergoing IAR and reconstructions. If preoperative imaging suggests articular tumour involvement, there appears to be no detrimental effect of undertaking EAR to optimise local control.

Periacetabular reconstruction following limb-salvage surgery for pelvic sarcomas

Limb-salvage surgery for pelvic sarcomas remains one of the most challenging surgical procedures for musculoskeletal oncologists. In the past several decades, various surgical techniques have been developed for periacetabular reconstruction following pelvic tumor resection. These methods include endoprosthetic reconstruction, allograft or autograft reconstruction, arthrodesis, and hip transposition. Each of these procedures has its own advantages and disadvantages, and there is no consensus or gold standard for periacetabular reconstruction. Consequently, this review provides an overview of the clinical outcomes for each of these reconstructive options following pelvic tumor resections. Overall, high complication rates are associated with the use of massive implants/grafts, and deep infection is generally the most common cause of reconstruction failure. Functional outcomes decline with the occurrence of severe complications. Further efforts to avoid complications using innovative techniques, such as antibiotic-laden devices, computer navigation, custom cutting jigs, and reduced use of implants/grafts, are crucial to improve outcomes, especially in patients at a high risk of complications.

A novel and secure technique of stemmed acetabular cup implantation in complex hip reconstructions: a comparative study and technical note

PURPOSE

The stemmed acetabular cup (SAC) can be considered in several complicated situations. This type of prosthesis uses the iliac isthmus, which is most often preserved, thus allowing solid anchorage. Its implantation is prone to mechanical complications intraoperatively, such as extra-isthmic effraction, fracture, and early aseptic loosening. The aim of our study was to compare a new technique using a flexible motorized reamer combined with isthmus catheterization (Group A) versus the standard technique deploying a rigid reamer alone (Group B).

MATERIALS AND METHODS

A retrospective analysis was carried out of the SACs implanted at our hospital. The main evaluation criterion was visualization of extra-isthmic effraction (EIE) of the stem.

RESULTS

Fifty-six SACs (Integra Lepine®, Genay, France) were implanted, 31 in group A and 25 in group B. The mean follow-up was 21.6 months ± 22.3. This study found fewer EIEs using a flexible motorized reamer (0 versus 5, p = 0.014), less perioperative bleeding (p = 0.054), and less aseptic loosening in group A (p = 0.034). There was no difference in terms of infection or other mechanical complications post-operatively between the two groups.

CONCLUSION

Using iliac catheterization combined with a flexible motorized reamer when implanting a SAC helps to avoid EIE and it also appears to reduce complications such as peri-operative bleeding and early aseptic loosening. We recommend use of this surgical technique rather than a rigid reamer alone, and this new technique should allow widespread and more accessible use of this specific type of implant.

Patient-Specific Implants for Pelvic Tumor Resections

Introduction Limb salvage surgery for periacetabular malignancies is technically demanding and associated with a considerable likelihood of postoperative complications and surgical revision. Reconstruction using custom-made implants represents the treatment of choice. This study was conducted to analyze treatment outcomes of custom-made implants in a single orthopaedic tumor center. Patients and Methods Twenty patients with a histologically verified periacetabular malignancy and a median follow up time of 5 (1-17) years were included. Results The median number of revision surgeries per patient was 1.5 (0-7). Complications were dislocations in 3 patients, aseptic loosening in 4 patients, deep infections in 9 patients, thromboembolic events in 5 patients and sciatic nerve lesions in 4 patients. Overall survival was 77% after one year, 69% after two years and 46% after five years. Median Harris Hip Score was 81 (37-92) points at last follow up. Conclusion Although internal hemipelvectomy and reconstruction using custom-made implants is linked with a high risk of postoperative complications, good functional outcomes can be regularly achieved. This information may help treating surgeons to find adequate indications, as eligible patients need to be critically selected and integrated into the decision-making process.

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

Limb-salvage reconstruction following resection of pelvic bone sarcomas involving the acetabulum

AIMS

Limb salvage for pelvic sarcomas involving the acetabulum is a major surgical challenge. There remains no consensus about what is the optimum type of reconstruction after resection of the tumour. The aim of this study was to evaluate the surgical outcomes in these patients according to the methods of periacetabular reconstruction.

METHODS

The study involved a consecutive series of 122 patients with a periacetabular bone sarcoma who underwent limb-salvage surgery involving a custom-made prosthesis in 65 (53%), an ice-cream cone prosthesis in 21 (17%), an extracorporeal irradiated autograft in 18 (15%), and nonskeletal reconstruction in 18 (15%).

RESULTS

The rates of major complications necessitating further surgery were 62%, 24%, 56%, and 17% for custom-made prostheses, ice-cream cone prostheses, irradiated autografts and nonskeletal reconstructions, respectively (p = 0.001). The ten-year cumulative incidence of failure of the reconstruction was 19%, 9%, 33%, and 0%, respectively. The major cause of failure was deep infection (11%), followed by local recurrence (6%). The mean functional Musculoskeletal Tumour Society (MSTS) scores were 59%, 74%, 64%, and 72%, respectively. The scores were significantly lower in patients with major complications than in those without complications (mean 52% (SD 20%) vs 74% (SD 19%); p < 0.001). For periacetabular resections involving the ilium, the mean score was the highest with custom-made prostheses (82% (SD 10%)) in patients without any major complication; however, nonskeletal reconstruction resulted in the highest mean scores (78% (SD 12%)) in patients who had major complications. For periacetabular resections not involving the ilium, significantly higher mean scores were obtained with ice-cream cone prostheses (79% (SD 17%); p = 0.031).

CONCLUSION

Functional outcome following periacetabular reconstruction is closely associated with the occurrence of complications requiring further surgery. For tumours treated with periacetabular and iliac resection, skeletal reconstruction may result in the best outcomes in the absence of complications, whereas nonskeletal reconstruction is a reasonable option if the risk of complications is high. For tumours requiring periacetabular resection without the ilium, reconstruction using an ice-cream cone prosthesis supported by antibiotic-laden cement is a reliable option. Cite this article: Bone Joint J 2021;103-B(4):795-803.

Pelvic reconstruction using an ice-cream cone prosthesis: correlation between the inserted length of the coned stem and surgical outcome

BACKGROUND

Acetabular reconstruction using an ice-cream cone prosthesis has been a reliable reconstruction option following pelvic tumour resection. However, it remains unknown which factor determines the success of this procedure. We aimed to determine risk factors for complications and functional loss in acetabular reconstruction using an ice-cream cone prosthesis.

PATIENTS AND METHODS

Fifty-four patients with malignant bone tumours who underwent acetabular reconstruction using an ice-cream cone prosthesis between 2004 and 2016 were studied. The bone-stem ratio was calculated as the ratio of the inserted length into the bone per the entire stem length.

RESULTS

A total of 26 (48%) patients had at least one complication and 11 patients (20%) required surgical interventions. The complication rates were 71% and 40% with a bone-stem ratio ≤ 50% and > 50%, respectively (p = 0.026), and the bone-stem ratio significantly stratified the risk of complications (≤ 50%: OR, 4.67 versus > 50%; p = 0.048). The mean MSTS score at the final follow-up was 60% (range 23-97%): the scores were significantly lower in patients with complications/leg-length discrepancy (52%) than in those without (79%; p = 0.002). The mean score with a bone-stem ratio ≤ 50% was significantly lower than the score with a ratio > 50%, especially in patients who underwent non-navigated reconstructions (33% versus 64%; p = 0.001).

CONCLUSION

The inserted length of the coned stem into residual bone was predictive of complications and functional outcome. Surgical indication for this procedure should be considered with the size of the remaining ilium to stabilise the prosthesis with a coned stem longer than half length.

Risk factors for early dislocation of the hip after periacetabular tumour resection and endoprosthetic reconstruction of the hemipelvis

AIMS

There is an increased risk of dislocation of the hip after the resection of a periacetabular tumour and endoprosthetic reconstruction of the defect in the hemipelvis. The aim of this study was to determine the rate and timing of dislocation and to identify its risk factors.

METHODS

To determine the dislocation rate, we conducted a retrospective single-institution study of 441 patients with a periacetabular tumour who had undergone a standard modular hemipelvic endoprosthetic reconstruction between 2003 and 2019. After excluding ineligible patients, 420 patients were enrolled. Patient-specific, resection-specific, and reconstruction-specific variables were studied using univariate and multivariate analyses.

RESULTS

The dislocation rate was 9.3% (n = 41). Dislocation was most likely to occur in the first three months after surgery. Four independent risk factors were found, one of which was older age at operation (p = 0.039). The odds ratios (ORs) of those aged ≥ 60 years and 30 to 60 years were 8.50 and 4.64, respectively, compared with those aged < 30 years. The other three risk factors were resection of gluteus maximus (p = 0.010, OR = 5.8), vertical shift of the centre of rotation (COR) of the hip by ≥ 20 mm (p = 0.008, OR = 3.60), and a type I+II+III pelvic resection (p = 0.014, OR = 3.04).

CONCLUSION

Hemipelvic endoprosthetic reconstruction after resection of a periacetabular tumour has a dislocation rate of 9.3% (n = 41). Patients are most likely to dislocate in the first three months after surgery. The risk is increased for older patients (especially those aged > 60 years) and for those with gluteus maximus resection, vertical shift of the COR ≥ 20 mm, and a type I+II+III pelvic resection. Cite this article: Bone Joint J 2021;103-B(2):382-390.

Comparison of reconstructive techniques after acetabular resection for pelvic chondrosarcoma

AIMS

Hip reconstruction after resection of a periacetabular chondrosarcoma is complex and associated with a high rate of complications. Previous reports have compared no reconstruction with historical techniques that are no longer used. The aim of this study was to compare the results of tantalum acetabular reconstruction to both historical techniques and no reconstruction.

METHODS

We reviewed 66 patients (45 males and 21 females) with a mean age of 53 years (24 to 81) who had undergone acetabular resection for chondrosarcoma. A total of 36 patients (54%) underwent acetabular reconstruction, most commonly with a saddle prosthesis (n = 13; 36%) or a tantalum total hip arthroplasty (THA) (n = 10; 28%). Mean follow-up was nine years (SD 4).

RESULTS

There was no difference in the mean age (p = 0.63), sex (p = 0.110), tumour volume (p = 0.646), or type of resection carried out (p > 0.05) between patients with and without reconstruction. Of the original 66 patients, 61 (92%) were ambulant at final follow-up. There was no difference in the proportion of patients who could walk in the reconstruction and 'no reconstruction' groups (p = 0.649). There was no difference in the mean Musculoskeletal Tumor Society (MSTS) score between patients who were reconstructed and those who were not (61% vs 56%; p = 0.378). Patients with a tantalum THA had a significantly (p = 0.015) higher mean MSTS score (78%) than those who were reconstructed with a saddle prosthesis (47%) or who had not been reconstructed (56%). Patients who had undergone reconstruction were more likely to have complications (81% vs 53%; p = 0.033).

CONCLUSION

Reconstruction after resection of the acetabulum is technically demanding. In selected cases, reconstruction is of benefit, especially when reconstruction is by tantalum THA; however, the follow-up for these patients remains mid-term. When not feasible, patients with no reconstruction have an acceptable functional outcome. Level of Evidence: Level III Therapeutic. Cite this article: Bone Joint J 2021;103-B(2):391-397.

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.

Reconstruction after periacetabular tumor resection with Lumic® endoprosthesis: What are the midterm results?

INTRODUCTION

This study aimed to analyze the midterm outcomes of LUMiC® endoprosthetic reconstruction following periacetabular resection of primary bone sarcomas and carcinoma metastases.

PATIENTS AND METHODS

We retrospectively reviewed the charts of 21 patients (11 male [52.3%], 10 female [47.6%]; mean age 47 ± 16 years) for whom a LUMiC® endoprosthesis (Implantcast) was used to reconstruct a periacetabular defect after internal hemipelvectomy. The tumor was pathologically diagnosed as Ewing's sarcoma in six (28.5%), chondrosarcoma in 10 (47.6%), and bone metastasis from carcinoma in five (23.8%) patients.

RESULTS

The median follow-up of patients was 57.8 months (95% confidence interval: 51.9-63.7). The implant survival rate at 1, 2, and 5 years were 95.2%, 85.7%, and 80.9%, respectively. The overall complication rate was 33.3% (n = 7). Four (19%) complications resulted in reconstruction failure. Total reoperation rate was 28.5% (n = 6). The complications were soft tissue failure/dislocation in two patients, aseptic loosening in one, infection in two, and local recurrence in two. At the time of study, seven patients were alive with no evidence of disease, seven were alive with disease, and seven died of disease. The 5-year overall survival rate and local recurrence-free survival rates were 67% and 76%, respectively. The median Musculoskeletal Tumor Society score at final follow-up was 70% (range: 50%-86.6%).

CONCLUSION

We conclude that LUMiC® endoprosthesis provides good functional outcomes and a durable reconstruct. Even though this reconstruction method presents some complications, it provides a stable pelvis in the management of periacetabular malignant tumors.

Adolescent pelvic chondrosarcoma, surgical treatment, and unusual reconstruction with pedestal conic cup (LUMiC®): A case report

An 18-year-old male patient was diagnosed pelvic chondrosarcoma histopathologically. Hip joint involvement was detected. No metastasis or neurovascular invasion was seen. Type I+II pelvic resection and hip reconstruction were planned with pedestal cup (LUMiC®) and proximal femur tumor prosthesis. Surgery was performed in lateral decubitus position with extensive triradiate incision. Pelvic wide resection was performed. At the second year of follow-up, implant failure was detected and patient was revised with same pedestal cup. Axial stability was supported by a L5 screw and connector from L5 vertebrae to LUMiC® prosthesis. Except the implant failure, no oncological complication or infection was observed during the final 36^th month follow-up.

3D-Printed Modular Hemipelvic Endoprosthetic Reconstruction Following Periacetabular Tumor Resection: Early Results of 80 Consecutive Cases

BACKGROUND

Reconstruction with an endoprosthesis following pelvic tumor resection has increased over the years. However, the long-term results reflect a disappointing frequency of mechanical complications and failures. In an attempt to enhance implant fixation, an electron beam melting (EBM)-based modular hemipelvic endoprosthesis was introduced. Our aim was to explore the preliminary clinical outcomes for patients who have been managed with this prosthesis.

METHODS

We reviewed the records of 80 consecutive patients who had been managed at a single center between June 2015 and September 2017. Chondrosarcoma was the predominant diagnosis (31.3%). Osseous metastases were diagnosed in 16 patients (20.0%). The position of the reconstructed metallic acetabulum was measured on an anteroposterior pelvic radiograph. Bone ingrowth was evaluated in 2 samples harvested from patients with tumor recurrence.

RESULTS

After a median duration of follow-up of 32.5 months (range, 9 to 52 months), no acetabular component instability was detected on radiographs. Histological sectioning of specimens harvested from 2 patients with tumor recurrence showed bone trabeculae extending toward the implant and bone ingrowth within the porous network. At the time of the latest follow-up, 59 patients (73.8%) were alive with no evidence of disease, 5 patients (6.3%) were alive with disease, and 16 patients (20.0%) had died of disease. Local recurrence occurred in 9 patients (11.3%). The mean Musculoskeletal Tumor Society score at the time of the latest follow-up was 83.9% (range, 43% to 100%). Complications occurred in 16 patients (20%), with wound dehiscence being the most common complication (8 patients; 10%). No aseptic loosening was found. Five patients (6.3%) had deep infection, and 2 patients (2.5%) had dislocation.

CONCLUSIONS

The use of a 3-dimensional (3D)-printed modular hemipelvic endoprosthesis with a highly porous metal interface represents a potential choice as a pelvic endoprosthesis after internal hemipelvectomy for the treatment of a primary or metastatic tumor. These preliminary results demonstrate stable fixation with acceptable early functional and radiographic outcomes.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Modified Harrington's procedure for periacetabular metastases in 89 cases: a reliable method for cancer patients with good functional outcome, especially with long expected survival

Background and purpose - The pelvis is the 3rd most common site of skeletal metastases. In some cases, periacetabular lesions require palliative surgical management. We investigated functional outcome, complications, and implant and patient survival after a modified Harrington's procedure.Patients and methods - This retrospective cohort study included 89 cases of surgically treated periacetabular metastases. All patients were treated with the modified Harrington's procedure including a restoration ring. Lesions were classified according to Harrington. Functional outcome was assessed by Harris Hip Score (HHS) and Oxford Hip Score (OHS). Postoperative complications, and implant and patient survival are reported.Results - The overall postoperative functional outcome was good to fair (OHS 37 and HHS 76). Sex, age, survival > 6 and 12 months, and diagnosis of the primary tumor affected functional outcome. Overall implant survival was 96% (95% Cl 88-100) at 1 year, 2 years, and 5 years; only 1 acetabular implant required revision. Median patient survival was 8 months (0-125). 10/89 patients had postoperative complications: 6 major complications, leading to revision surgery, and 4 minor complications.Interpretation - Our modified Harrington's procedure with a restoration ring to achieve stable fixation, constrained acetabular cup to prevent dislocation, and antegrade iliac screws to prevent cranial protrusion is a reliable reconstruction for periacetabular metastases and results in a good functional outcome in patients with prolonged survival. A standardized procedure and low complication rate encourage the use of this method for all Harrington class defects.

Rate and risk factors for wound complications after internal hemipelvectomy

AIMS

Although internal hemipelvectomy is associated with a high incidence of morbidity, especially wound complications, few studies have examined rates of wound complications in these patients or have identified factors associated with the consequences. The present study aimed to: 1) determine the rate of wound and other complications requiring surgery after internal hemipelvectomy; and 2) identify factors that affect the rate of wound complications and can be used to stratify patients by risk of wound complications.

METHODS

The medical records of 123 patients undergoing internal hemipelvectomy were retrospectively reviewed, with a focus on both overall complications and wound complications. Logistic regression analyses were performed to examine the association between host, tumour, and surgical factors and rates of postoperative wound complications.

RESULTS

The overall rate of postoperative complications requiring surgery was 49.6%. Wound complications were observed in 34.1% of patients, hardware-related complications in 13.2%, graft-related complications in 9.1%, and local recurrence in 5.7%. On multivariate analysis, extrapelvic tumour extension (odds ratio (OR) 23.28; 95% confidence interval (CI), 1.97 to 274.67; p = 0.012), both intra- and extrapelvic tumour extension (OR 46.48; 95% CI, 3.50 to 617.77; p = 0.004), blood transfusion ≥ 20 units (OR 50.28; 95% CI, 1.63 to 1550.32; p = 0.025), vascular sacrifice of the internal iliac artery (OR 64.56; 95% CI, 6.33 to 658.43; p < 0.001), and use of a structural allograft (OR, 6.57; 95% CI, 1.70 to 25.34; p = 0.001) were significantly associated with postoperative wound complications.

CONCLUSION

Internal hemipelvectomy is associated with high rates of morbidity, especially wound complications. Several host, tumour, and surgical variables are associated with wound complications. The ability to stratify patients by risk of wound complications can help refine surgical and wound-healing planning and may lead to better outcomes in patients undergoing internal hemipelvectomy. Cite this article: Bone Joint J 2020;102-B(3):280-284.

Extra-articular resection for bone sarcomas involving the hip joint

AIM

The aim of this study was to determine the oncologic, functional, and clinical outcomes after the extra-articular resection and limb-salvage reconstruction of the hip joint.

METHODS

A retrospective study of 34 patients who underwent extra-articular resection of the hip joint for bone sarcomas between 1996 and 2016 was conducted. The primary tumor site was pelvis in 26 patients (76%) and femur in eight (24%).

RESULTS

The surgical margins achieved were clear in 31 (91%) patients, and seven (21%) patients developed local recurrence; mostly occurring in pelvic tumors (n = 6). The 3-year overall survival was 63% with a median follow-up of 38 months (range, 5-219), which showed no statistical difference in tumor location. The most common complication was deep infection (n = 7) and dislocation (n = 7), mostly seen in pelvic tumors. Implant failure was seen in two patients with pelvic tumors, while no failure was noted in patients with femoral tumors. The median Musculoskeletal Tumour Society score was 69%; 67% for pelvic tumors and 73% for femoral tumors (P = .535).

CONCLUSION

Despite complex surgery, extra-articular resection of the hip joint can achieve oncologically and functionally acceptable outcomes. While tumors of the pelvis are associated with a higher incidence of infection and local recurrence after resection, resection of tumors involving the femur are well tolerated.

The long-term outcomes of modified Harrington procedure using antegrade pins for periacetabular metastasis and haematological diseases

AIMS

The aim of this study was to present the long-term surgical outcomes, complications, implant survival, and causes of implant failure in patients treated with the modified Harrington procedure using antegrade large diameter pins.

PATIENTS AND METHODS

A cohort of 50 consecutive patients who underwent the modified Harrington procedure for periacetabular metastasis or haematological malignancy between January 1996 and April 2018 were studied. The median follow-up time for all survivors was 3.2 years (interquartile range 0.9 to 7.6 years).

RESULTS

The five-year overall survival rate was 33% for all the patients. However, implant survival rates were 100% and 46% at five and ten years, respectively. Eight patients survived beyond five years. There was no immediate perioperative mortality or complications. A total of 15 late complications occurred in 11 patients (22%). Five patients (10%) required further surgery to treat complications. The most frequent complication was pin breakage without evidence of acetabular loosening (6%). Two patients (4%) underwent revision for aseptic loosening at 6.5 and 8.9 years after surgery. Ambulatory status and pain level were improved in 83% and 89%, respectively.

CONCLUSION

The modified Harrington procedure for acetabular destruction has low complication rates, good functional outcome, and improved pain relief in selected patients Cite this article: Bone Joint J 2019;101-B:1557-1562.

Surgical treatment for pelvic Ewing sarcoma: What is a safe and functional acetabular reconstruction when combined with modern multidisciplinary treatments?

PURPOSE

The purpose of this study was to clarify which local treatment is oncologically and functionally effective in pelvic Ewing sarcoma (ES).

METHODS

A consecutive series of patients who underwent pelvic resections and acetabular reconstructions after chemotherapy between 1986 and 2016 at a supra-regional center were evaluated.

RESULTS

The cohort consisted of 35 patients. The 5-year overall survival (OS) and local recurrence-free survival (LRFS) was 61% and 72%, respectively. Preoperative radiotherapy (RT) and surgery provided an excellent/good histological response in 92% and achieved significantly better OS (5 years, 64%) and LRFS (5 years, 100%) than surgery alone or surgery with postoperative RT. The Musculoskeletal Tumor Society functional scores were significantly better in patients with hip transposition than those with structural reconstructions (74% vs 57%; P = .031) using custom-made prostheses, irradiated autografts, and ice-cream cone prostheses. These scores were significantly lower if patients had deep infection (P = .035), which was the most common complication (28%) in structural reconstructions but did not occur in hip transposition even when performed after preoperative RT.

CONCLUSION

Acetabular reconstruction with hip transposition resulted in no deep infection and superior function in patients with pelvic ES even when combined with preoperative RT, which improved tumor necrosis and rate of local control and survival.

Temporary External Fixation Can Stabilize Hip Transposition Arthroplasty After Resection of Malignant Periacetabular Bone Tumors

BACKGROUND

The choice of reconstructive procedure to restore limb function is challenging after internal hemipelvectomy. Hip transposition arthroplasty, also known as resection arthroplasty, removes a malignant or aggressive tumor of the pelvis and acetabulum after which the remaining femoral head is moved proximally to the lateral surface side of the sacrum or the underside of the resected ilium after internal hemipelvectomy. It may provide reasonable functional results and have some advantages such as lowering the risk of an infected implant compared with other reconstructions because no foreign implants are used. Hip transposition is generally managed with prolonged bed rest or immobilization postoperatively to stabilize the soft tissue surrounding the remaining femur. Because enabling patients to be mobile while the soft tissues heal might be advantageous, we reviewed our experience with an external fixation for this procedure.

QUESTIONS/PURPOSES

(1) Does temporary external fixation facilitate postoperative physiotherapy in patients who undergo hip transposition arthroplasty? (2) What functional Musculoskeletal Tumor Society (MSTS) scores were achieved at short term in a small series of patients treated with hip transposition and temporary external fixation? (3) What were the complications of using external fixation in a small series of patients who received it for malignant tumors?

METHODS

Between 2008 and 2012, we treated seven patients (three men and four women; median age, 37 years; age range, 18-53 years) with acetabular resection for malignant bone tumors; all were managed with a hip transposition, initially stabilized using external fixation. No other types of procedures were used for this indication in this period. Minimum followup in this retrospective study was 45 months, except for one patient who died at 18 months (range of followup duration, 18-90 months; median followup, 57 months), and no patients were lost to followup. The pins for external fixation were inserted into the affected side of the femur and the healthy contralateral ilium. External fixation was removed 6 weeks postoperatively and weightbearing was started at that time. Preoperative chemotherapy was administrated in four patients, but postoperative chemotherapy was delayed since it was given after external fixation removal in three patients. The postoperative rehabilitation course and functional results were assessed by chart review, functional results were determined using MSTS scores, tallied by physiotherapists who were not part of the surgical team, and complications were ascertained through chart review. Major complications were defined as complications that were treated with additional operations, such as deep infection, or ones that could cause severe postoperative dysfunction, such as nerve injury.

RESULTS

With temporary external fixation, standing next to a bed was achieved in median 7 days (range, 6-9 days) postoperatively, transferring to a wheel chair in median 8 days (range, 6-28 days), and gait training using parallel bars in median 15 days (range, 7-48 days). At most recent followup, three patients could walk without a crutch or cane, three could walk with a cane, and one could walk with a crutch. The median MSTS score at most recent followup (median, 57 months) was 63%. Two patients had complications that resulted in reoperations; one had a wound dehiscence, and one had an abdominal herniation that gradually developed, and which was reconstructed using polypropylene mesh 2 years after pelvic resection. Two patients had nerve palsies that recovered by the end of the first year. All patients had pin tract infections that resolved with nonsurgical approaches.

CONCLUSIONS

Hip transposition with temporary external fixation can stabilize the bone soft tissue after pelvic resection. Although we did not have a comparison group of patients, we believe that external fixation facilitates early postoperative physiotherapy and rehabilitation and provides good functional results without major surgical complications. Because it delays the resumption of chemotherapy, more patients with longer followup are needed to determine whether this will be associated with poorer oncologic results.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

A general multi-objective topology optimization methodology developed for customized design of pelvic prostheses

In this study, a multi-objective topology optimization method has been formulated and carried out for various resection types, with minimization of a weighted sum of the compliance (maximized stiffness) under six routine activities of daily life as the objective function and volume reduction as a constraint. Unique prosthetic geometries with low weight and remarkable strength closely matching the pelvic bone shape were obtained. The strength of the optimized implants was investigated through finite element analysis and it has been found that the initial geometries of the optimized implants could withstand the static loading conditions of various routine activities having less stress concentration areas. A 3D printed patient-specific topology optimized hemi-pelvic prosthesis has been designed based on the proposed method and implanted successfully in a patient with pelvic sarcoma. Therefore, pelvic prostheses can be designed and then manufactured via additive manufacturing technologies with the minimum material in less time and having robust mechanical fixation responses. Conclusively, the topology optimization method used for the design of pelvic prostheses improves the biomechanical performance of the implants with reduced weight and higher stiffness than the traditional implants. Including the topology optimization procedure in the phase of designing patient-specific pelvic implants is therefore, highly recommended.

Multiflora and Gram-Negative Microorganisms Predominate in Infections Affecting Pelvic Endoprostheses Following Tumor Resection

BACKGROUND

Periprosthetic infections after pelvic reconstruction are common, with reported rates ranging from 11% to 53%. Management of these infections is troublesome, as they commonly necessitate multiple surgical interventions and implant removal. The epidemiology and outcomes of these infections are largely unknown. The aim of this study was to analyze the causative microorganisms and the clinical outcome of treatment in a series of patients with pelvic endoprostheses affected by infection following tumor resection.

METHODS

In this retrospective, multicenter cohort study, we identified all patients who developed an infection after endoprosthetic reconstruction in periacetabular tumor resection, between 2003 and 2017. The microorganisms that were isolated during the first debridement were recorded, as were the number of reoperations for ongoing infection, the antimicrobial treatment strategy, and the outcome of treatment.

RESULTS

In a series of 70 patients who underwent pelvic endoprosthetic reconstruction, 18 (26%) developed an infection. The type of pelvic resection according to the Enneking-Dunham classification was type P2-3 in 14 (78%) of these patients and type P2 in 4 (22%). Median follow-up was 66 months. Fourteen (78%) of the 18 patients with infection had a polymicrobial infection. Enterobacteriaceae were identified on culture for 12 (67%). Of a total 42 times that a microorganism was isolated, the identified pathogen was gram-negative in 26 instances (62%). Microorganisms associated with intestinal flora were identified 32 times (76%). At the time of latest follow-up, 9 (50%) of the patients had the original implant in situ. Of these, 2 had a fistula and another 2 were receiving suppressive antibiotic therapy. In the remaining 9 (50%) of the patients, the original implant had been removed. At the time of final follow-up, 3 of these had a second implant in situ. The remaining 6 patients had undergone no secondary reconstruction.

CONCLUSIONS

Infections that affect pelvic endoprostheses are predominantly polymicrobial and caused by gram-negative microorganisms, and may be associated with intestinal flora. This differs fundamentally from mono-bacterial gram-positive causes of conventional periprosthetic joint infections and may indicate a different pathogenesis. Our results suggest that prophylaxis and empiric treatment may need to be re-evaluated.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Pelvic reconstruction following resection of tumour involving the whole ilium and acetabulum

Background

Functional reconstruction following resection of pelvic tumours with the ileum and the acetabulum involvement is challenging and demanding. The aim of this study was to evaluate the results of these patients receiving pelvic reconstruction with a femoral head autograft plus a hemipelvic prosthesis.

Methods

Eighteen patients receiving pelvic reconstruction with a femoral head autograft plus a hemipelvic prosthesis following resection of pelvic tumours involving the whole ileum and the acetabulum were included in this study from April 2006 to June 2014. Oncological status, functional results, and complications of these selected patients were analysed.

Results

The follow-up was 15–125 months (median 43). The functional MSTS-93 scores of the 18 patients available for the functional analysis were 37–87% (mean 60.7%). Complications occurred in seven patients (31.8%); dislocation in two (9%); and deep infection in three patients (13.6%) and two patients healed well following thorough debridement and antibiotic treatment. Five patients had local recurrence (22.7%). Lung metastases occurred in eight patients; seven died of disease and one lived after the metastasectomy. The 5-year overall Kaplan–Meier survival and disease-free survival rates were 61.7% and 50%, respectively.

Conclusions

The procedure of femoral head autograft plus hemipelvic prosthesis was an effective method to reconstruct the defect following the whole ileum and the acetabulum resection; the functional outcomes were satisfactory, and it had an acceptable complication rate.

Treatment of intra-articular hip malignancy with extra-articular resection, preservation of the acetabular columns, and total hip arthroplasty

Intra-articular malignant lesions of the hip present significant challenges. Resection often requires large resection of the acetabular bone and pelvic columns. Concurrent reconstruction options after intra-articular hip tumors are challenging and may necessitate the use of techniques and implants with uncertain long-term survivorship. We present a case of an intra-articular hip malignancy with extra-articular resection and preservation of the acetabular columns with reconstruction using a cementless acetabular shell fixed with screws.

In vitro experimental and numerical study on biomechanics and stability of a novel adjustable hemipelvic prosthesis

Hemipelvic prostheses are used to reconstruct the damaged pelvis due to bone tumors and traumas. However, biomechanical properties of the reconstructed pelvis remain unclear, causing difficulties to implant development and prediction of surgical outcome. In this study, a novel adjustable hemipelvic prosthesis for the Type 1-3 pelvis resection was used to reconstruct the intact pelvic ring. Two types of Pedicle Screw Rod Systems were proposed to improve the stability of fixation between the prosthesis and the bone. Finite Element models of the reconstructed pelvis were built to analyze the performance of the prosthesis and PSRS. Moreover, an in vitro experimental study was performed to measure the deformation of the human reconstructed pelvis. Numerical results agree well with the experimental data. It was found that displacements and stresses bilaterally transferred more evenly in the reconstructed pelvis enhanced by bilateral Pedicle Screw Rod System. The load-transfer function of the pelvis under double-leg standing stance could be recovered. The bilateral pedicle system has better biomechanical performance than the unilateral pedicle system.

The usefulness of wide excision assisted by a computer navigation system and reconstruction using a frozen bone autograft for malignant acetabular bone tumors: a report of two cases

Background

Difficult resection of tumors from regions with complex local anatomy, such as the pelvis and sacrum, is likely to result in inadequate surgical margins (intralesional or marginal); this is because three-dimensional osteotomy is difficult particularly around the acetabulum. Additionally, removal of the joint makes reconstruction very difficult; thus, retention of good function also becomes difficult. In musculoskeletal oncology, computer navigation systems are still not widely used to prevent tumor-positive margins. We performed wide excision with guidance from a computer navigation system and reconstruction using frozen bone autografts for malignant pelvic bone tumors in two patients, and we obtained excellent functional and oncological outcomes. Here we present these patients and discuss our approach.

Case presentation

Case 1: A 12-year-old girl presented with Ewing sarcoma of the left pelvis (PI-II). We performed wide excision assisted by a computer navigation system with the osteotomy of the load surface of acetabulum and reconstruction using a frozen bone autograft. At the final follow-up, she showed excellent function and was alive without the disease. Moreover, she did not have osteoarthritis of the left hip joint.

Case 2: A 71-year-old woman presented with dedifferentiated chondrosarcoma of the right pelvis (PII-III). We performed wide excision assisted by a computer navigation system with osteotomy avoiding load surface of the acetabulum and reconstruction using a frozen bone autograft; there was no tumor at the load surface. At the final follow-up, she showed good function, was alive without the disease, and did not have osteoarthritis of the left hip joint.

Conclusions

Wide excision assisted by a computer navigation system and reconstruction using a frozen bone autograft are very useful for the management/treatment of extremely difficult cases such as malignant pelvic bone tumors, particularly those including the acetabulum.

Pelvic reconstruction following resection of malignant bone tumours using a stemmed acetabular pedestal cup

Aims

Pelvic reconstruction after the resection of a tumour around the acetabulum is a challenging procedure due to the complex anatomy and biomechanics. Several pelvic endoprostheses have been introduced, but the rates of complication remain high. Our aim was to review the use of a stemmed acetabular pedestal cup in the management of these patients.

Patients and Methods

The study involved 48 patients who underwent periacetabular reconstruction using a stemmed pedestal cup (Schoellner cup; Zimmer Biomet Inc., Warsaw, Indiana) between 2000 and 2013. The indications for treatment included a primary bone tumour in 27 patients and metastatic disease in 21 patients. The mean age of the patients at the time of surgery was 52 years (16 to 83).

Results

At a median follow-up of 6.6 years (95% confidence interval 4.6 to 8.2), local control was achieved in all patients; 19 patients had died (16 of disease). Complications occurred in 19 patients (40%), of which deep infection was the most common, affecting eight patients (17%). Seven patients (15%) had a dislocation of the hip. Aseptic loosening was found in three patients (6%). Two (4%) underwent hindquarter amputation for non-oncological reasons. The risk of revision, with death being treated as a competing event, was 28% at one year, 39% at five years and 48% at ten years post-operatively. The mean Musculoskeletal Tumour Society Score at final follow-up was 71% (27% to 93%).

Conclusion

This type of reconstruction is a satisfactory option for the treatment of patients with a periacetabular tumour. There remains, however, a high rate of complication, which may be reduced by future modifications of the device such as silver coating and tripolar articulation. Cite this article: Bone Joint J 2017;99-B:841–8.

LUMiC® Endoprosthetic Reconstruction After Periacetabular Tumor Resection: Short-term Results

BACKGROUND

Reconstruction of periacetabular defects after pelvic tumor resection ranks among the most challenging procedures in orthopaedic oncology, and reconstructive techniques are generally associated with dissatisfying mechanical and nonmechanical complication rates. In an attempt to reduce the risk of dislocation, aseptic loosening, and infection, we introduced the LUMiC^® prosthesis (implantcast, Buxtehude, Germany) in 2008. The LUMiC^® prosthesis is a modular device, built of a separate stem (hydroxyapatite-coated uncemented or cemented) and acetabular cup. The stem and cup are available in different sizes (the latter of which is also available with silver coating for infection prevention) and are equipped with sawteeth at the junction to allow for rotational adjustment of cup position after implantation of the stem. Whether this implant indeed is durable at short-term followup has not been evaluated.

QUESTIONS/PURPOSES

(1) What proportion of patients experience mechanical complications and what are the associated risk factors of periacetabular reconstruction with the LUMiC^® after pelvic tumor resection? (2) What proportion of patients experience nonmechanical complications and what are the associated risk factors of periacetabular reconstruction with the LUMiC^® after pelvic tumor resection? (3) What is the cumulative incidence of implant failure at 2 and 5 years and what are the mechanisms of reconstruction failure? (4) What is the functional outcome as assessed by Musculoskeletal Tumor Society (MSTS) score at final followup?

METHODS

We performed a retrospective chart review of every patient in whom a LUMiC^® prosthesis was used to reconstruct a periacetabular defect after internal hemipelvectomy for a pelvic tumor from July 2008 to June 2014 in eight centers of orthopaedic oncology with a minimum followup of 24 months. Forty-seven patients (26 men [55%]) with a mean age of 50 years (range, 12-78 years) were included. At review, 32 patients (68%) were alive. The reverse Kaplan-Meier method was used to calculate median followup, which was equal to 3.9 years (95% confidence interval [CI], 3.4-4.3). During the period under study, our general indications for using this implant were reconstruction of periacetabular defects after pelvic tumor resections in which the medial ilium adjacent to the sacroiliac joint was preserved; alternative treatments included hip transposition and saddle or custom-made prostheses in some of the contributing centers; these were generally used when the medial ilium was involved in the tumorous process or if the LUMiC^® was not yet available in the specific country at that time. Conventional chondrosarcoma was the predominant diagnosis (n = 22 [47%]); five patients (11%) had osseous metastases of a distant carcinoma and three (6%) had multiple myeloma. Uncemented fixation (n = 43 [91%]) was preferred. Dual-mobility cups (n = 24 [51%]) were mainly used in case of a higher presumed risk of dislocation in the early period of our study; later, dual-mobility cups became the standard for the majority of the reconstructions. Silver-coated acetabular cups were used in 29 reconstructions (62%); because only the largest cup size was available with silver coating, its use depended on the cup size that was chosen. We used a competing risk model to estimate the cumulative incidence of implant failure.

RESULTS

Six patients (13%) had a single dislocation; four (9%) had recurrent dislocations. The risk of dislocation was lower in reconstructions with a dual-mobility cup (one of 24 [4%]) than in those without (nine of 23 [39%]) (hazard ratio, 0.11; 95% CI, 0.01-0.89; p = 0.038). Three patients (6%; one with a preceding structural allograft reconstruction, one with poor initial fixation as a result of an intraoperative fracture, and one with a cemented stem) had loosening and underwent revision. Infections occurred in 13 reconstructions (28%). Median duration of surgery was 6.5 hours (range, 4.0-13.6 hours) for patients with an infection and 5.3 hours (range, 2.8-9.9 hours) for those without (p = 0.060); blood loss was 2.3 L (range, 0.8-8.2 L) for patients with an infection and 1.5 L (range, 0.4-3.8 L) for those without (p = 0.039). The cumulative incidences of implant failure at 2 and 5 years were 2.1% (95% CI, 0-6.3) and 17.3% (95% CI, 0.7-33.9) for mechanical reasons and 6.4% (95% CI, 0-13.4) and 9.2% (95% CI, 0.5-17.9) for infection, respectively. Reasons for reconstruction failure were instability (n = 1 [2%]), loosening (n = 3 [6%]), and infection (n = 4 [9%]). Mean MSTS functional outcome score at followup was 70% (range, 33%-93%).

CONCLUSIONS

At short-term followup, the LUMiC^® prosthesis demonstrated a low frequency of mechanical complications and failure when used to reconstruct the acetabulum in patients who underwent major pelvic tumor resections, and we believe this is a useful reconstruction for periacetabular resections for tumor or failed prior reconstructions. Still, infection and dislocation are relatively common after these complex reconstructions. Dual-mobility articulation in our experience is associated with a lower risk of dislocation. Future, larger studies will need to further control for factors such as dual-mobility articulation and silver coating. We will continue to follow our patients over the longer term to ascertain the role of this implant in this setting.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Reconstruction After Hemipelvectomy With the Ice-Cream Cone Prosthesis: What Are the Short-term Clinical Results?

BACKGROUND

Reconstruction after internal hemipelvectomy resection likely provides better function than hindquarter amputation. However, many reconstruction methods have been used, complications with these approaches are common, and function often is poor; because of these issues, it seems important to investigate alternative implants and surgical techniques.

QUESTIONS/PURPOSES

The purposes of this study were (1) to identify the frequency of surgical site complications and infection associated with the use of the Ice-Cream Cone prosthesis for reconstruction after hemipelvectomy for oncological indications; (2) to evaluate the Musculoskeletal Tumor Society (MSTS) outcomes scores in a small group of patients treated with this implant in the short term; and (3) to quantify the surgical margins and frequency of local recurrence in the short term in this group of patients.

METHODS

Between 2008 and 2013, one center performed a total of 27 internal hemipelvectomies for oncological indications. Of those, 23 (85%) were treated with reconstruction. Our general indications for reconstruction were patients whose pelvic stability was affected by the resection and whose general condition was sufficiently strong to tolerate the reconstructive procedure. Of those patients undergoing reconstruction, 14 (61%) were treated with an Ice-Cream Cone-style implant (Coned^®; Stanmore Worldwide Ltd, Elstree, UK; and Socincer^® custom-made implant for the pelvis, Gijón, Spain), whereas nine others were treated with other implants or allografts. The indications during this time for using the Ice-Cream Cone implant were pelvic tumors affecting the periacetabular area without iliac wing involvement. Of those 14, 10 were available for followup at a minimum of 2 years (median, 3 years; range, 2-5 years) unless a study endpoint (wound complication, infection, or local recurrence) was observed earlier. Study endpoints were ascertained by chart review performed by one of the authors.

RESULTS

Surgical site complications occurred in five patients. Of those, two developed superficial infections with necrosis, two developed deep infections, and one patient developed wound necrosis without apparent infection. No prostheses were removed as a result of these complications [corrected]. Median MSTS score was 19 out of 30 when 0 is the worst possible result and 30 a perfect function and emotional status. Five of seven primary tumors had wide margin surgery and three of seven developed local recurrences by the end of the followup.

CONCLUSIONS

Pelvic reconstruction with the Ice-Cream Cone prosthesis yielded fair functional results at short-term followup. Longer term surveillance is called for to see whether this implant will represent an improvement over available reconstructive alternatives such as allograft, custom-made implants, and saddle prostheses. We are cautiously optimistic and continue to use this implant when we need to reconstruct the periacetabular area in patients without Enneking Zone 1 involvement.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Reconstruction with 3D-printed pelvic endoprostheses after resection of a pelvic tumour

Aims

The aims of this retrospective study were to report the feasibility of using 3D-printing technology for patients with a pelvic tumour who underwent reconstruction.

Patients and Methods

A total of 35 patients underwent resection of a pelvic tumour and reconstruction using 3D-printed endoprostheses between September 2013 and December 2015. According to Enneking’s classification of bone defects, there were three Type I lesions, 12 Type II+III lesions, five Type I+II lesions, two Type I+II+III lesions, ten type I+II+IV lesions and three type I+II+III+IV lesions. A total of three patients underwent reconstruction using an iliac prosthesis, 12 using a standard hemipelvic prosthesis and 20 using a screw-rod connected hemipelvic prosthesis.

Results

All patients had an en bloc resection. Margins were wide in 15 patients, marginal in 14 and intralesional in six. After a mean follow-up of 20.5 months (6 to 30), 25 patients survived without evidence of disease, five were alive with disease and five had died from metastatic disease. Complications included seven patients with delayed wound healing and two with a dislocation of the hip. None had a deep infection. For the 30 surviving patients, the mean Musculoskeletal Society 93 score was 22.7 (20 to 25) for patients with an iliac prosthesis, 19.8 (15 to 26) for those with a standard prosthesis, and 17.7 (9 to 25) for those with a screw-rod connected prosthesis.

Conclusion

The application of 3D-printing technology can facilitate the precise matching and osseointegration between implants and the host bone. We found that the use of 3D-printed pelvic prostheses for reconstruction of the bony defect after resection of a pelvic tumour was safe, without additional complications, and gave good short-term functional results. Cite this article: Bone Joint J 2017;99-B:267–75.