Aims. The aim of this study was to compare the biomechanical models of two frequently used techniques for reconstructing severe acetabular defects with pelvic discontinuity in revision total hip arthroplasty (THA) – the Trabecular Metal Acetabular Revision System (TMARS) and custom triflange acetabular components (CTACs) – using virtual modelling. Methods. Pre- and postoperative CT scans from ten patients who underwent revision with the TMARS for a Paprosky IIIB acetabular defect with pelvic discontinuity were retrospectively collated. Computer models of a CTAC implant were designed from the preoperative CT scans of these patients. Computer models of the TMARS reconstruction were segmented from postoperative CT scans using a semi-automated method. The amount of bone removed, the implant-bone apposition that was achieved, and the restoration of the centre of rotation of the hip were compared between all the actual TMARS and the virtual CTAC implants. Results. The median amount of bone removed for TMARS reconstructions was significantly greater than for CTAC implants (9.07 cm. 3. (interquartile range (IQR) 5.86 to 21.42) vs 1.16 cm. 3. (IQR 0.42 to 3.53) (p = 0.004). There was no significant difference between the median overall implant-bone apposition between TMARS reconstructions and CTAC implants (54.8 cm. 2. (IQR 28.2 to 82.3) vs 56.6 cm. 2. (IQR 40.6 to 69.7) (p = 0.683). However, there was significantly more implant-bone apposition within the residual acetabulum (45.2 cm. 2. (IQR 28.2 to 72.4) vs 25.5 cm. 2. (IQR 12.8 to 44.1) (p = 0.001) and conversely significantly less apposition with the outer cortex of the pelvis for TMARS implants compared with CTAC reconstructions (0 cm. 2. (IQR 0 to 13.1) vs 23.2 cm. 2. (IQR 16.4 to 30.6) (p = 0.009). The mean centre of rotation of the hip of TMARS reconstructions differed by a mean of 11.1 mm (3 to 28) compared with CTAC implants. Conclusion. In using TMARS, more bone is removed, thus achieving more implant-bone apposition within the residual acetabular bone. In CTAC implants, the amount of bone removed is minimal, while the implant-bone apposition is more evenly distributed between the residual acetabulum and the outer cortex of the pelvis. The differences suggest that these implants used to treat pelvic discontinuity might achieve short- and long-term stability through different biomechanical mechanisms. Cite this article: Bone Joint J 2024;106-B(5 Supple B):74–81

Aims. Venous tumour thrombus (VTT) is a rare finding in osteosarcoma. Despite the high rate of VTT in osteosarcoma of the pelvis, there are very few descriptions of VTT associated with extrapelvic primary osteosarcoma. We therefore sought to describe the prevalence and presenting features of VTT in osteosarcoma of both the pelvis and the limbs. Methods. Records from a single institution were retrospectively reviewed for 308 patients with osteosarcoma of the pelvis or limb treated between January 2000 and December 2022. Primary lesions were located in an upper limb (n = 40), lower limb (n = 198), or pelvis (n = 70). Preoperative imaging and operative reports were reviewed to identify patients with thrombi in proximity to their primary lesion. Imaging and histopathology were used to determine presence of tumour within the thrombus. Results. Tumours abutted the blood vessels in 131 patients (43%) and encased the vessels in 30 (10%). Any form of venous thrombus was identified in 31 patients (10%). Overall, 21 of these thrombi were determined to be involved with the tumour based on imaging (n = 9) or histopathology (n = 12). The rate of VTT was 25% for pelvic osteosarcoma and 1.7% for limb osteosarcoma. The most common imaging features associated with histopathologically proven VTT were enhancement with contrast (n = 12; 100%), venous enlargement (n = 10; 83%), vessel encasement (n = 8; 66%), and visible intraluminal osteoid matrix (n = 6; 50%). Disease-specific survival (DSS) for patients with VTT was 95% at 12 months (95% CI 0.87 to 1.00), 50% at three years (95% CI 0.31 to 0.80), and 31% at five years (95% CI 0.14 to 0.71). VTT was associated with worse DSS (hazard ratio 2.3 (95% CI 1.11 to 4.84). Conclusion. VTT is rare with osteosarcoma and occurs more commonly in the pelvis than the limbs. Imaging features suggestive of VTT include enhancement with contrast, venous dilation, and vessel encasement. VTT portends a worse prognosis for patients with osteosarcoma, with a similar survivability to metastatic disease. Cite this article: Bone Joint J 2024;106-B(8):865–870

The October 2023 Hip & Pelvis Roundup. 360. looks at: Femoroacetabular impingement syndrome at ten years – how do athletes do?; Venous thromboembolism in patients following total joint replacement: are transfusions to blame?; What changes in pelvic sagittal tilt occur 20 years after total hip arthroplasty?; Can stratified care in hip arthroscopy predict successful and unsuccessful outcomes?; Hip replacement into your nineties; Can large language models help with follow-up?; The most taxing of revisions – proximal femoral replacement for periprosthetic joint infection – what’s the benefit of dual mobility?

The December 2024 Hip & Pelvis Roundup. 360. looks at: Total hip arthroplasty after femoral neck fractures versus osteoarthritis at one-year follow-up: a comparative, retrospective study; Excellent mid-term survival of a monoblock conical prosthesis in treating atypical and complex femoral anatomy with total hip arthroplasty; Hip arthroscopy for femoroacetabular impingement improves sexual function; Fast-track hip arthroplasty does not increase complication rates; Ten-year experience with same-day discharge outpatient total hip arthroplasty: patient demographics changed, but safe outcomes were maintained

The August 2023 Hip & Pelvis Roundup. 360. looks at: Using machine learning to predict venous thromboembolism and major bleeding events following total joint arthroplasty; Antibiotic length in revision total hip arthroplasty; Preoperative colonization and worse outcomes; Short stem cemented total hip arthroplasty; What are the outcomes of one- versus two-stage revisions in the UK?; To cement or not to cement? The best approach in hemiarthroplasty; Similar re-revisions in cemented and cementless femoral revisions for periprosthetic femoral fractures in total hip arthroplasty; Are hip precautions still needed?

The June 2024 Hip & Pelvis Roundup. 360. looks at: Machine learning did not outperform conventional competing risk modelling to predict revision arthroplasty; Unravelling the risks: incidence and reoperation rates for femoral fractures post-total hip arthroplasty; Spinal versus general anaesthesia for hip arthroscopy: a COVID-19 pandemic- and opioid epidemic-driven study; Development and validation of a deep-learning model to predict total hip arthroplasty on radiographs; Ambulatory centres lead in same-day hip and knee arthroplasty success; Exploring the impact of smokeless tobacco on total hip arthroplasty outcomes: a deeper dive into postoperative complications

The April 2023 Hip & Pelvis Roundup. 360. looks at: Do technical errors determine outcomes of operatively managed femoral neck fractures in younger adults?; Single-stage or two-stage revision for hip prosthetic joint infection (INFORM); Fixation better than revision in type B periprosthetic fractures of taper slip stems; Can you maximize femoral head size at the expense of liner thickness?; Plasma D-dimer for periprosthetic joint infection?; How important is in vivo oxidation?; Total hip arthroplasty for HIV patients with osteonecrosis

The February 2023 Hip & Pelvis Roundup. 360. looks at: Total hip arthroplasty or internal fixation for hip fracture?; Significant deterioration in quality of life and increased frailty in patients waiting more than six months for total hip or knee arthroplasty: a cross-sectional multicentre study; Long-term cognitive trajectory after total joint arthroplasty; Costal cartilage grafting for a large osteochondral lesion of the femoral head; Foley catheters not a problem in the short term; Revision hips still a mortality burden?; How to position implants with a robotic arm; Uncemented stems in hip fracture?

The April 2024 Hip & Pelvis Roundup. 360. looks at: Impaction bone grafting for femoral revision hip arthroplasty with the Exeter stem; Effect of preoperative corticosteroids on postoperative glucose control in total joint replacement; Tranexamic acid in patients with a history of venous thromboembolism; Bisphosphonate use may be associated with an increased risk of periprosthetic hip fracture; A balanced approach: exploring the impact of surgical techniques on hip arthroplasty outcomes; A leap forward in hip arthroplasty: dual-mobility bearings reduce groin pain; A new perspective on complications: the link between blood glucose and joint infection risks

The December 2023 Hip & Pelvis Roundup. 360. looks at: Early hip fracture surgery is safe for patients on direct oral anticoagulants; Time to return to work by occupational class after total hip or knee arthroplasty; Is there a consensus on air travel following hip and knee arthroplasty?; Predicting whether patients will achieve minimal clinically important differences following hip or knee arthroplasty; High-dose dual-antibiotic-loaded cement for hip hemiarthroplasty in the UK (WHiTE 8): a randomized controlled trial; Vitamin E – a positive thing in your poly?; Hydroxapatite-coated femoral stems: is there a difference in fixation?

The June 2023 Hip & Pelvis Roundup. 360. looks at: Machine learning to identify surgical candidates for hip and knee arthroplasty: a viable option?; Poor outcome after debridement and implant retention; Can you cement polyethylene liners into well-fixed acetabular shells in hip revision?; Revision stem in primary arthroplasties: the Exeter 44/0 125 mm stem; Depression and anxiety: could they be linked to infection?; Does where you live affect your outcomes after hip and knee arthroplasties?; Racial disparities in outcomes after total hip arthroplasty and total knee arthroplasty are substantially mediated by socioeconomic disadvantage both in black and white patients

The October 2024 Hip & Pelvis Roundup. 360. looks at: Does the primary surgical approach matter when choosing the approach for revision total hip arthroplasty?; Time to achieve the minimal clinically important difference in primary total hip arthroplasty: comparison of anterior and posterior surgical approaches; To scope or not to scope: arthroscopy as an adjunct to PAO does not provide better clinical outcomes at one year than PAO alone; Re-exploring horizons in hip resurfacing: two-year results of a ceramic-on-ceramic hip resurfacing; Association between tranexamic acid and decreased periprosthetic joint infection risk in patients undergoing total hip and knee arthroplasty; Octogenarians fare well: in revision for infection age is not a bar

The August 2024 Hip & Pelvis Roundup. 360. looks at: Understanding perceived leg length discrepancy post-total hip arthroplasty: the role of pelvic obliquity; Influence of femoral stem design on revision rates in total hip arthroplasty; Outcomes of arthroscopic labral treatment of femoroacetabular impingement in adolescents; Characteristics and quality of online searches for direct anterior versus posterior approach for total hip arthroplasty; Rapid return to braking after anterior and posterior approach total hip arthroplasty; How much protection does a collar provide?; Timing matters: reducing infection risk in total hip arthroplasty with corticosteroid injection intervals; Identifying pain recovery patterns in total hip arthroplasty using PROMIS data

The February 2024 Hip & Pelvis Roundup. 360. looks at: Trial of vancomycin and cefazolin as surgical prophylaxis in arthroplasty; Is preoperative posterior femoral neck tilt a risk factor for fixation failure? Cemented versus uncemented hemiarthroplasty for displaced intracapsular fractures of the hip; Periprosthetic fractures in larger hydroxyapatite-coated stems: are collared stems a better alternative for total hip arthroplasty?; Postoperative periprosthetic fracture following hip arthroplasty with a polished taper slip versus composite beam stem; Is oral tranexamic acid as good as intravenous?; Stem design and the risk of early periprosthetic femur fractures following THA in elderly patients; Does powered femoral broaching compromise patient safety in total hip arthroplasty?

The December 2022 Hip & Pelvis Roundup. 360. looks at: Fix and replace: simultaneous fracture fixation and hip arthroplasty for acetabular fractures in older patients; Is the revision rate for femoral neck fracture lower for total hip arthroplasty than for hemiarthroplasty?; Femoral periprosthetic fractures: data from the COMPOSE cohort study; Dual-mobility cups and fracture of the femur; What’s the deal with outcomes for hip and knee arthroplasty outcomes internationally?; Osteochondral lesions of the femoral head: is costal cartilage the answer?

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. It is uncertain whether instrumented spinal fixation in nonambulatory children with neuromuscular scoliosis should finish at L5 or be extended to the pelvis. Pelvic fixation has been shown to be associated with up to 30% complication rates, but is regarded by some as the standard for correction of deformity in these conditions. The incidence of failure when comparing the most caudal level of instrumentation, either L5 or the pelvis, using all-pedicle screw instrumentation has not previously been reported. In this retrospective study, we compared nonambulatory patients undergoing surgery at two centres: one that routinely instrumented to L5 and the other to the pelvis. Methods. In all, 91 nonambulatory patients with neuromuscular scoliosis were included. All underwent surgery using bilateral, segmental, pedicle screw instrumentation. A total of 40 patients underwent fusion to L5 and 51 had their fixation extended to the pelvis. The two groups were assessed for differences in terms of clinical and radiological findings, as well as complications. Results. The main curve (MC) was a mean of 90° (40° to 141°) preoperatively and 46° (15° to 82°) at two-year follow-up in the L5 group, and 82° (33° to 116°) and 19° (1° to 60°) in the pelvic group (p < 0.001 at follow-up). Correction of MC and pelvic obliquity (POB) were statistically greater in the pelvic group (p < 0.001). There was no statistically significant difference in the operating time, blood loss, or complications. Loss of MC correction (> 10°) was more common in patients fixated to the pelvis (23% vs 3%; p = 0.032), while loss of pelvic obliquity correction was more frequent in the L5 group (25% vs 0%; p = 0.007). Risk factors for loss of correction (either POB or MC) included preoperative coronal imbalance (> 50 mm, odds ratio (OR) 11.5, 95%confidence interval (CI) 2.0 to 65; p = 0.006) and postoperative sagittal imbalance (> 25 mm, OR 11.0, 95% CI1.9 to 65; p = 0.008). Conclusion. We found that patients undergoing pelvic fixation had a greater correction of MC and POB. The rate of complications was not different. Preoperative coronal and postoperative sagittal imbalance were associated with increased risks of loss of correction, regardless of extent of fixation. Therefore, we recommend pelvic fixation in all nonambulatory children with neuromuscular scoliosis where coronal or sagittal imbalance are present preoperatively. Cite this article: Bone Joint J 2020;102-B(2):261–267

Aims. Custom-made partial pelvis replacements (PPRs) are increasingly used in the reconstruction of large acetabular defects and have mainly been designed using a triflange approach, requiring extensive soft-tissue dissection. The monoflange design, where primary intramedullary fixation within the ilium combined with a monoflange for rotational stability, was anticipated to overcome this obstacle. The aim of this study was to evaluate the design with regard to functional outcome, complications, and acetabular reconstruction. Methods. Between 2014 and 2023, 79 patients with a mean follow-up of 33 months (SD 22; 9 to 103) were included. Functional outcome was measured using the Harris Hip Score and EuroQol five-dimension questionnaire (EQ-5D). PPR revisions were defined as an endpoint, and subgroups were analyzed to determine risk factors. Results. Implantation was possible in all cases with a 2D centre of rotation deviation of 10 mm (SD 5.8; 1 to 29). PPR revision was necessary in eight (10%) patients. HHS increased significantly from 33 to 72 postoperatively, with a mean increase of 39 points (p < 0.001). Postoperative EQ-5D score was 0.7 (SD 0.3; -0.3 to 1). Risk factor analysis showed significant revision rates for septic indications (p ≤ 0.001) as well as femoral defect size (p = 0.001). Conclusion. Since large acetabular defects are being treated surgically more often, custom-made PPR should be integrated as an option in treatment algorithms. Monoflange PPR, with primary iliac fixation, offers a viable treatment option for Paprosky III defects with promising functional results, while requiring less soft-tissue exposure and allowing immediate full weightbearing. Cite this article: Bone Jt Open 2024;5(8):688–696

Aims. The aim of this study was to identify factors that determine outcomes of treatment for patients with chondroblastic osteosarcomas (COS) of the limbs and pelvis. Patients and Methods. The authors carried out a retrospective review of prospectively collected data from 256 patients diagnosed between 1979 and 2015. Of the 256 patients diagnosed with COS of the pelvis and the limbs, 147 patients (57%) were male and 109 patients (43%) were female. The mean age at presentation was 20 years (0 to 90). Results. In all, 82% of the patients had a poor response to chemotherapy, which was associated with the presence of a predominantly chondroblastic component (more than 50% of tumour volume). The incidence of local recurrence was 15%. Synchronous or metachronous metastasis was diagnosed in 60% of patients. Overall survival was 51% and 42% after five and ten years, respectively. Limb localization and wide surgical margins were associated with a lower risk of local recurrence after multivariable analysis, while the response to chemotherapy was not. Local recurrence, advanced patient age, pelvic tumours, and large volume negatively influenced survival. Resection of pulmonary metastases was associated with a survival benefit in the limited number of patients in whom this was undertaken. Conclusion. COS demonstrates a poor response to chemotherapy and a high incidence of metastases. Wide resection is associated with improved local control and overall survival, while excision of pulmonary metastases is associated with improved survival in selected patients. Cite this article: Bone Joint J 2019;101-B:739–744

Aims . Osteosarcoma of the pelvis is a particularly difficult tumour to treat as it often presents late, may be of considerable size and/or associated with metastases when it presents, and is frequently chondroid in origin and resistant to chemotherapy. The aim of this study was to review our experience of managing this group of patients and to identify features predictive of a poor outcome. Patients and Methods. Between 1983 and 2014, 121 patients, (74 females and 47 males) were treated at a single hospital: 74 (61.2%) patients had a primary osteosarcoma and 47 (38.8%) had an osteosarcoma which was secondary either to Paget’s disease (22; 18.2%) or to previous pelvic irradiation (25; 20.7%). . The mean age of those with a primary osteosarcoma was 29.3 years (nine to 76) and their mean follow-up 2.9 years (0 to 29). The mean age of those with a secondary sarcoma was 61.9 years (15 to 85) and their mean follow-up was one year (0 to 14). . A total of 22 patients with a primary sarcoma (52.4%) and 20 of those with a secondary sarcoma (47.6%) had metastases at the time of presentation. . Results. The disease-specific survival at five years for all patients was 27.2%. For those without metastases at the time of diagnosis, the five-year survival was 32.7%. Factors associated with a poor outcome were metastases at diagnosis and secondary tumours. In primary osteosarcoma, sacral location, surgical margin and a diameter > 10 cm were associated with a poor outcome. Conclusion. In this, the largest single series of patients with an osteosarcoma of the pelvis treated in a single hospital, those with secondary tumours and those with metastases at presentation had a particularly poor outcome. For those with a primary sarcoma, sacral location, an intralesional margin and a diameter of > 10 cm were poor prognostic indicators. Cite this article: Bone Joint J 2016;98-B:555–63