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

Peri-acetabular tumour resections and their subsequent reconstruction are among the most challenging procedures in orthopaedic oncology. Despite the fact that a number of different pelvic endoprostheses have been introduced, rates of complication remain high and long-term results are mostly lacking. . In this retrospective study, we aimed to evaluate the outcome of reconstructing a peri-acetabular defect with a pedestal cup endoprosthesis after a type 2 or type 2/3 internal hemipelvectomy. A total of 19 patients (11M:8F) with a mean age of 48 years (14 to 72) were included, most of whom had been treated for a primary bone tumour (n = 16) between 2003 and 2009. After a mean follow-up of 39 months (28 days to 8.7 years) seven patients had died. After a mean follow-up of 7.9 years (4.3 to 10.5), 12 patients were alive, of whom 11 were disease-free. Complications occurred in 15 patients. Three had recurrent dislocations and three experienced aseptic loosening. There were no mechanical failures. Infection occurred in nine patients, six of whom required removal of the prosthesis. Two patients underwent hindquarter amputation for local recurrence. The implant survival rate at five years was 50% for all reasons, and 61% for non-oncological reasons. The mean Musculoskeletal Tumor Society score at final follow-up was 49% (13 to 87). Based on these poor results, we advise caution if using the pedestal cup for reconstruction of a peri-acetabular tumour resection. Cite this article: Bone Joint J 2014;96-B:1706–12

Aims. Survival rates and local control after resection of a sarcoma of the pelvis compare poorly to those of the limbs and have a high incidence of complications. The outcome for patients who need a hindquarter amputation (HQA) to treat a pelvic sarcoma is poor. Our aim was to evaluate the patient, tumour, and reconstructive factors that affect the survival of the patients who undergo HQA for primary or recurrent pelvic sarcoma. Methods. We carried out a retrospective review of all sarcoma patients who had undergone a HQA in a supraregional sarcoma unit between 1996 and 2018. Outcomes included oncological, surgical, and survival characteristics. Results. A total of 136 patients, with a mean age of 51 (12 to 83) underwent HQA, 91 for a bone sarcoma and 45 for a soft tissue sarcoma. The overall survival (OS) after primary HQA for a bone sarcoma was 90.7 months (95% confidence interval (CI) 64.1 to 117.2). In patients undergoing a secondary salvage HQA it was 90.3 months (95% CI 58.1 to 122.5) (p = 0.727). For those treated for a soft tissue sarcoma (STS), the mean OS was 59.3 months (95% CI 31.1 to 88.6) for patients with a primary HQA, and 12.5 months (95% CI 9.4 to 15.5) for those undergoing a secondary salvage HQA (p = 0.038). On multivariate analysis, high histological grade (hazard ratio (HR) 2.033, 95% CI 1.127 to 3.676; p = 0.018) and a diagnosis of STS (HR 1.653, 95% CI 1.027 to 2.660; p = 0.039) were associated with a poor prognosis. The 30-day mortality for patients with curative intent was 0.8% (1/128). For those in whom surgery was carried out with palliative intent it was 33.3% (2/6) (p = 0.001). In total, 53.7% (n = 73) of patients had at least one complication with 23.5% (n = 32) requiring at least one further operation. Direct closure was inferior to flap reconstruction in terms of complete primary wound healing (60.0% (3/5) vs 82.0% (82/100); p = 0.023). Conclusion. In carefully selected patients HQA is associated with satisfactory overall survival, with a low risk of perioperative mortality, but considerable morbidity. However, caution must be exercised when considering the procedure for palliation due to the high incidence of early postoperative mortality. Cite this article: Bone Joint J 2020;102-B(6):788–794

Aims. Few studies dealing with chondrosarcoma of the pelvis are currently available. Different data about the overall survival and prognostic factors have been published but without a detailed analysis of surgery-related complications. We aimed to analyse the outcome of a series of pelvic chondrosarcomas treated at a single institution, with particular attention to the prognostic factors. Based on a competing risk model, our objective was to identify risk factors for the development of complications. Patients and Methods. In a retrospective single-centre study, 58 chondrosarcomas (26 patients alive, 32 patients dead) of the pelvis were reviewed. The mean follow-up was 13 years (one week to 23.1 years). Results. A total of 26 patients (45%) were alive and 32 patients (55%) had died. Overall survival was 76%, 55% and 45% at one, five and ten years post-operatively, respectively. In a competing risk model the cumulative risk of the development of a surgery-related complication was 64% at six months and 69% at one year, post-operatively, respectively. Endoprosthetic reconstruction was a significant risk factor for the development of complications (p = 0.006). Complications were not significantly related to age or the location or grade of the tumour (p = 0.823, p = 0.976, p = 0.858). The development of complications did not have a negative effect on survival (p = 0.147). Conclusion. This is the first study with competing risk analysis of surgery-related complications in patients with a pelvic chondrosarcoma. The surgery in these patients remains prone to complications. Endoprosthetic reconstruction significantly increases the risk of the development of complications (p = 0.006). A competing risk model showed that the development of complications does not have a negative influence on overall survival (p = 0.147). An aggressive, surgical resection with the goal of achieving wide margins whenever possible remains the mainstay of treatment. . Cite this article: Bone Joint J 2017;99-B:686–96

Aims. The sacrum is frequently invaded by a pelvic tumour. The aim of this study was to review our experience of treating this group of patients and to identify the feasibility of a new surgical classification in the management of these tumours. Patients and Methods. We reviewed 141 patients who, between 2005 and 2014, had undergone surgical excision of a pelvic tumour with invasion of the sacrum. In a new classification, pelvisacral (Ps) I, II, and III resections refer to a sagittal osteotomy through the ipsilateral wing of the sacrum, through the sacral midline, or lateral to the contralateral sacral foramina, respectively. A Ps a resection describes a pelvic osteotomy through the ilium and a Ps b resection describes a concurrent resection of the acetabulum with osteotomies performed through the pubis and ischium or the pubic symphysis. Within each type, surgical approaches were standardized to guide resection of the tumour. Results. The mean operating time was 5.2 hours (. sd. 1.7) and the mean intraoperative blood loss was 1895 ml (. sd. 1070). Adequate margins were achieved in 112 (79.4%) of 141 patients. Nonetheless, 30 patients (21.3%) had local recurrence. The mean Musculoskeletal Tumor Society (MSTS93) lower-limb function score was 68% (. sd. 19; 17 to 100). According to the proposed classification, 92 patients (65%) underwent a Ps I resection, 33 patients (23%) a Ps II resection, and 16 (11%) patients a Ps III resection. Overall, 82 (58%) patients underwent a Ps a resection and 59 (42%) patient a Ps b resections. The new classification predicted surgical outcome. Conclusion. We propose a comprehensive classification of surgical approaches for tumours of the pelvis with sacral invasion. Analysis showed that this classification helped in the surgical management of such patients and had predictive value for surgical outcomes. Cite this article: Bone Joint J 2018;100-B:798–805

Aims. The aim of this study was to investigate the local recurrence rate at an extended follow-up in patients following navigated resection of primary pelvic and sacral tumours. Patients and Methods. This prospective cohort study comprised 23 consecutive patients (nine female, 14 male) who underwent resection of a primary pelvic or sacral tumour, using computer navigation, between 2010 and 2012. The mean age of the patients at the time of presentation was 51 years (10 to 77). The rates of local recurrence and mortality were calculated using the Kaplan–Meier method. Results. Bone resection margins were all clear and there were no bony recurrences. At a mean follow-up for all patients of 59 months (12 to 93), eight patients (34.8%) developed soft-tissue local recurrence, with a cumulative rate of local recurrence at six-years of 35.1% (95% confidence interval (CI) 19.3 to 58.1). The cumulative all-cause rate of mortality at six-years was 26.1% (95% CI 12.7 to 49.1). Conclusion. Despite the positive early experience with navigated-assisted resection, local recurrence rates remain high. With increasing knowledge of the size of soft-tissue margins required to reduce local recurrence and the close proximity of native structures in the pelvis, we advise against compromising resection to preserve function, and encourage surgeons to reduce local recurrence by prioritizing wide resection margins of the tumour. Cite this article: Bone Joint J 2019;101-B:484–490

Endoprosthetic replacement of the pelvis is one of the most challenging types of limb-salvage surgery, with a high rate of complications. In an attempt to reduce this and build greater versatility into the reconstruction process, a new type of pelvic endoprosthesis was developed in 2003, based on the old McKee-Farrar prosthesis. This study reviews the outcomes in 27 patients who had an ice-cream cone pelvic prosthesis inserted at two different specialist bone tumour centres in the United Kingdom over the past six years. The indications for treatment included primary bone tumours in 19 patients and metastatic disease in two, and six implants were inserted following failure of a previous pelvic reconstruction. Most of the patients had a P2+P3 resection as classified by Enneking, and most had resection of the ilium above the sciatic notch. The mean age of the patients at operation was 49 years (13 to 81). Complications occurred in ten patients (37.0%), of which dislocation was the most common, affecting four patients (14.8%). A total of three patients (11.1%) developed a deep infection around the prosthesis but all were successfully controlled by early intervention and two patients (7.4%) developed a local recurrence, at the same time as widespread metastases appeared. In one patient the prosthesis was removed for severe pain. This method of treatment is still associated with high morbidity, but early results are promising. Complications are diminishing with increasing experience

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

To date, all surgical techniques used for reconstruction of the pelvic ring following supra-acetabular tumour resection produce high complication rates. We evaluated the clinical, oncological and functional outcomes of a cohort of 35 patients (15 men and 20 women), including 21 Ewing’s sarcomas, six chondrosarcomas, three sarcomas not otherwise specified, one osteosarcoma, two osseous malignant fibrous histiocytomas, one synovial cell sarcoma and one metastasis. The mean age of the patients was 31 years (8 to 79) and the latest follow-up was carried out at a mean of 46 months (1.9 to 139.5) post-operatively. We undertook a functional reconstruction of the pelvic ring using polyaxial screws and titanium rods. In 31 patients (89%) the construct was encased in antibiotic-impregnated polymethylmethacrylate. Preservation of the extremities was possible for all patients. The survival rate at three years was 93.9% (95% confidence interval (CI) 77.9 to 98.4), at five years it was 82.4% (95% CI 57.6 to 93.4). For the 21 patients with Ewing’s sarcoma it was 95.2% (95% CI 70.7 to 99.3) and 81.5% (95% CI 52.0 to 93.8), respectively. Wound healing problems were observed in eight patients, deep infection in five and clinically asymptomatic breakage of the screws in six. The five-year implant survival was 93.3% (95% CI 57.8 to 95.7). Patients were mobilised at a mean of 3.5 weeks (1 to 7) post-operatively. A post-operative neurological defect occurred in 12 patients. The mean Musculoskeletal Tumor Society score at last available follow-up was 21.2 (10 to 27). This reconstruction technique is characterised by simple and oncologically appropriate applicability, achieving high primary stability that allows early mobilisation, good functional results and relatively low complication rates. Cite this article: Bone Joint J 2013;95-B:1410–16

We report our early experience with a new peri-acetabular reconstruction endoprosthesis used for pelvic reconstruction after tumour resection. The outcome of 21 patients who underwent limb salvage following type II pelvic resection and reconstruction using the peri-acetabular reconstruction prosthesis between 2000 and 2006 was retrospectively reviewed. This prosthesis was designed to use the remaining part of the ilium to support a horizontally placed acetabular component secured with internal fixation and bone cement. Into this device a constrained acetabular liner is positioned which is articulates with a conventional femoral component to which a modular extension and modular head are attached. The mean follow-up was 20.5 months (1 to 77). The most common complications were deep infection, superficial wound infections, and dislocation. The mean musculoskeletal tumor society functional outcome score for the survivors was 20.1(11 to 27). We recommend the use of the peri-acetabular reconstruction prosthesis for reconstruction of large defects after type II pelvic resection, as this design has a greater inherent stability over other available prostheses

We review the treatment of pelvic Ewing’s sarcoma by the implantation of extracorporeally-irradiated (ECI) autografts and compare the outcome with that of other reported methods. We treated 13 patients with ECI autografts between 1994 and 2004. There were seven males and six females with a median age of 15.7 years (interquartile range (IQR) 12.2 to 21.7). At a median follow-up of five years (IQR 1.8 to 7.4), the disease-free survival was 69% overall, and 75% if one patient with local recurrence after initial treatment elsewhere was excluded. Four patients died from distant metastases at a mean of 17 months (13 to 23). There were three complications which required operative intervention; one was a deep infection which required removal of the graft. The functional results gave a mean Musculoskeletal Tumor Society score of 85% (60% to 97%), a mean Toronto extremity salvage score of 86% (69% to 100%) and a mean Harris hip score of 92 (67 to 100). We conclude that ECI grafting is a suitable form of treatment for localised and resectable pelvic Ewing’s sarcoma

Aims. The aim of this study was to describe the use of 3D-printed sacral endoprostheses to reconstruct the pelvic ring and re-establish spinopelvic stability after total en bloc sacrectomy (TES) and to review its outcome. Patients and Methods. We retrospectively reviewed 32 patients who underwent TES in our hospital between January 2015 and December 2017. We divided the patients into three groups on the basis of the method of reconstruction: an endoprosthesis group (n = 10); a combined reconstruction group (n = 14), who underwent non-endoprosthetic combined reconstruction, including anterior spinal column fixation; and a spinopelvic fixation (SPF) group (n = 8), who underwent only SPF. Spinopelvic stability, implant survival (IS), intraoperative haemorrhage rate, and perioperative complication rate in the endoprosthesis group were documented and compared with those of other two groups. Results. The mean overall follow-up was 22.1 months (9 to 44). In the endoprosthesis group, the mean intraoperative hemorrhage was 3530 ml (1600 to 8100). Perioperative complications occurred in two patients; both had problems with wound healing. After a mean follow-up of 17.7 months (12 to 38), 9/10 patients could walk without aids and 8/10 patients were not using analgesics. Imaging evidence of implant failure was found in three patients, all of whom had breakage of screws and/or rods. Only one of these, who had a local recurrence, underwent re-operation, at which solid bone-endoprosthetic osseointegration was found. The mean IS using re-operation as the endpoint was 32.5 months (95% confidence interval 23.2 to 41.8). Compared with the other two groups, the endoprosthesis group had significantly better spinopelvic stability and IS with no greater intraoperative haemorrhage or perioperative complications. Conclusion. The use of 3D-printed endoprostheses for reconstruction after TES provides reliable spinopelvic stability and IS by facilitating osseointegration at the bone-implant interfaces, with acceptable levels of haemorrhage and complications. Cite this article: Bone Joint J 2019;101-B:880–888

We reviewed 124 patients with a conventional pelvic chondrosarcoma who had been treated over a period of 20 years. We recorded the type of tumour (central or peripheral), type of operation (limb salvage surgery or hemipelvectomy), the grade of tumour, local recurrence and/or metastases, in order to identify the factors which might influence survival. More satisfactory surgical margins were achieved for central tumours or in those patients treated by hemipelvectomy. However, grade 1 tumours, whatever the course, did not develope metastases or cause death, while grade 3 tumours had the worst outcome and prognosis. Central, high-grade tumours require aggressive surgical treatment in order to achieve adequate surgical margins, particularly in those lesions located close to the sacroiliac joint. By contrast, grade 1 peripheral chondrosarcomas may be treated with contaminated margins in order to reduce operative morbidity, but without reducing survival

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.

We retrospectively evaluated 18 patients with a mean age of 37.3 years (14 to 72) who had undergone pelvic reconstruction stabilised with a non-vascularised fibular graft after resection of a primary bone tumour. The mean follow-up was 10.14 years (2.4 to 15.7). The mean Musculoskeletal Tumor Society Score was 76.5% (50% to 100%). Primary union was achieved in the majority of reconstructions within a mean of 22.9 weeks (7 to 60.6). The three patients with delayed or nonunion all received additional therapy (chemotherapy/radiation) (p = 0.0162). The complication rate was comparable to that of other techniques described in the literature. Non-vascularised fibular transfer to the pelvis is a simpler, cheaper and quicker procedure than other currently described techniques. It is a biological reconstruction with good results and a relatively low donor site complication rate. However, adjuvant therapy can negatively affect the outcome of such grafts

The aim of this study was to evaluate the functional and oncological outcome of extracorporeally irradiated autografts used to reconstruct the pelvis after a P1/2 internal hemipelvectomy.

The study included 18 patients with a primary malignant bone tumour of the pelvis. There were 13 males and five females with a mean age of 24.8 years (8 to 62). Of these, seven had an osteogenic sarcoma, six a Ewing’s sarcoma, and five a chondrosarcoma. At a mean follow-up of 51.6 months (4 to 185), nine patients had died with metastatic disease while nine were free from disease. Local recurrence occurred in three patients all of whom eventually died of their disease. Deep infection occurred in three patients and required removal of their graft in two while the third underwent a hindquarter amputation for extensive flap necrosis.

The mean Musculoskeletal Tumor Society functional score of the 16 patients who could be followed-up for at least 12 months was 77% (50 to 90). Those 15 patients who completed the Toronto Extremity Salvage Score questionnaire had a mean score of 71% (53 to 85).

Extracorporeal irradiation and re-implantation of bone is a valid method of reconstruction after an internal hemipelvectomy. It has an acceptable morbidity and a functional outcome that compares favourably with other available reconstructive techniques.

Cite this article: Bone Joint J 2014;96-B:1404–10

Aims. Ilium is the most common site of pelvic Ewing’s sarcoma (ES). Resection of the ilium and iliosacral joint causes pelvic disruption. However, the outcomes of resection and reconstruction are not well described. In this study, we report patients’ outcomes after resection of the ilium and iliosacral ES and reconstruction with a tibial strut allograft. Methods. Medical files of 43 patients with ilium and iliosacral ES who underwent surgical resection and reconstruction with a tibial strut allograft between January 2010 and October 2021 were reviewed. The lesions were classified into four resection zones: I. 1. , I. 2. , I. 3. , and I. 4. , based on the extent of resection. Functional outcomes, oncological outcomes, and surgical complications for each resection zone were of interest. Functional outcomes were assessed using a Musculoskeletal Tumor Society (MSTS) score and Toronto Extremity Salvage Score (TESS). Results. The mean age of the patients was 17 years (SD 9.1). At a mean follow-up of 70.8 months (SD 50), the mean functional outcomes were 24.2 points (SD 6.3) for MSTS and 81 points (SD 11) for TESS. The mean MSTS and TESS scores were associated with the iliac resection zone (< 0.001). Nine patients (20.9%) had local recurrence. The recurrence was not associated with the zone of iliac resection (p = 0.324). The two-year disease-free survival of the patients was 69.4%. The mean time to graft union was longer in patients with the I. 4. resection zone (p < 0.001). The complication rate was 34.9%, and nerve palsy (11.6%) was the most common. The rate of surgical complications was not associated with the resection zone. Conclusion. Reconstruction using tibial strut allograft is an efficient procedure after the resection of the ilium and iliosacral ES. Functional outcomes and complications of iliac ES depend on the resection zone, and inferior outcomes could be generally expected when more segments of the pelvic ring are resected, even if it is reconstructed. Cite this article: Bone Jt Open 2024;5(5):385–393

Aims. Internal hemipelvectomy without reconstruction of the pelvis is a viable treatment for pelvic sarcoma; however, the time it takes to return to excellent function is quite variable. Some patients require greater time and rehabilitation than others. To determine if psoas muscle recovery is associated with changes in ambulatory function, we retrospectively evaluated psoas muscle size and limb-length discrepancy (LLD) before and after treatment and their correlation with objective functional outcomes. Methods. T1-weighted MR images were evaluated at three intervals for 12 pelvic sarcoma patients following interval hemipelvectomy without reconstruction. Correlations between the measured changes and improvements in Timed Up and Go test (TUG) and gait speed outcomes were assessed both independently and using a stepwise multivariate regression model. Results. Increased ipsilesional psoas muscle size from three months postoperatively to latest follow-up was positively correlated with gait speed improvement (r = 0.66). LLD at three months postoperatively was negatively correlated with both TUG (r = -0.71) and gait speed (r = -0.61). Conclusion. This study suggests that psoas muscle strengthening and minimizing initial LLD will achieve the greatest improvements in ambulatory function. LLD and change in hip musculature remain substantial prognostic factors for achieving the best clinical outcomes after internal hemipelvectomy. Changes in psoas size were correlated with the amount of functional improvement. Several patients in this study did not return to their preoperative ipsilateral psoas size, indicating that monitoring changes in psoas size could be a beneficial rehabilitation strategy. Cite this article: Bone Joint J 2023;105-B(3):323–330

Aims. Controversy exists as to what should be considered a safe resection margin to minimize local recurrence in high-grade pelvic chondrosarcomas (CS). The aim of this study is to quantify what is a safe margin of resection for high-grade CS of the pelvis. Methods. We retrospectively identified 105 non-metastatic patients with high-grade pelvic CS of bone who underwent surgery (limb salvage/amputations) between 2000 and 2018. There were 82 (78%) male and 23 (22%) female patients with a mean age of 55 years (26 to 84). The majority of the patients underwent limb salvage surgery (n = 82; 78%) compared to 23 (22%) who had amputation. In total, 66 (64%) patients were grade 2 CS compared to 38 (36%) grade 3 CS. All patients were assessed for stage, pelvic anatomical classification, type of resection and reconstruction, margin status, local recurrence, distant recurrence, and overall survival. Surgical margins were stratified into millimetres: < 1 mm; > 1 mm but < 2 mm; and > 2 mm. Results. The disease-­specific survival (DSS) at five years was 69% (95% confidence interval (CI) 56% to 81%) and 51% (95% CI 31% to 70%) for grade 2 and 3 CS, respectively (p = 0.092). The local recurrence-free survival (LRFS) at five years was 59% (95% CI 45% to 72%) for grade 2 CS and 42% (95% CI 21% to 63%) for grade 3 CS (p = 0.318). A margin of more than 2 mm was a significant predictor of increased LRFS (p = 0.001). There was a tendency, but without statistical significance, for a > 2 mm margin to be a predictor of improved DSS. Local recurrence (LR) was a highly significant predictor of DSS, analyzed in a competing risk model (p = 0.001). Conclusion. Obtaining wide margins in the pelvis remains challenging for high-grade pelvic CS. On the basis of our study, we conclude that it is necessary to achieve at least a 2 mm margin for optimal oncological outcomes in patients with high-grade CS of the pelvis. Cite this article: Bone Joint J 2021;103-B(6):1150–1154

Aims. For rare cases when a tumour infiltrates into the hip joint, extra-articular resection is required to obtain a safe margin. Endoprosthetic reconstruction following tumour resection can effectively ensure local control and improve postoperative function. However, maximizing bone preservation without compromising surgical margin remains a challenge for surgeons due to the complexity of the procedure. The purpose of the current study was to report clinical outcomes of patients who underwent extra-articular resection of the hip joint using a custom-made osteotomy guide and 3D-printed endoprosthesis. Methods. We reviewed 15 patients over a five-year period (January 2017 to December 2022) who had undergone extra-articular resection of the hip joint due to malignant tumour using a custom-made osteotomy guide and 3D-printed endoprosthesis. Each of the 15 patients had a single lesion, with six originating from the acetabulum side and nine from the proximal femur. All patients had their posterior column preserved according to the surgical plan. Results. Postoperative pathological assessment revealed a negative surgical margin was achieved in all patients. At final follow-up, 13.3% (2/15) died and no recurrence occurred. The overall survival was 81.7% at five years. None of the patients showed any signs of aseptic loosening, and no wound healing issues were observed. In total, 20% (3/15) developed complications, with two cases of early hip dislocation and one case of deep infection. The cumulative incidence of mechanical and non-mechanical failure in this series was 13.7% and 9.3%, respectively, at five years. In this cohort, the mean time to full weightbearing was 5.89 (SD 0.92) weeks and the mean Musculoskeletal Tumor Society score was 24.1 (SD 4.4). Conclusion. For patients with a hip joint tumour who met the inclusion criteria and were deemed suitable for posterior column preservation, a custom-made osteotomy guide combined with 3D-printed endoprosthesis is worth performing when treating patients who require extra-articular resection of the hip joint, as it can achieve adequate margin for local control, maximize bone preservation to maintain pelvic ring integrity, reduce the risk of complications by simplifying the surgical procedure, and allow for more precise reconstruction for better function. Cite this article: Bone Jt Open 2024;5(11):1027–1036