The purpose of this study was to evaluate the long-term outcome of patients with a sacral chordoma and the surgical management of locally recurrent disease. Between October 1990 and August 2013 we operated on 54 consecutive patients with a sacral chordoma. There were 34 men and 20 women with a mean age of 60 years (25 to 86). The mean maximum diameter of the tumour was 9.3 cm (3 to 20). The mean follow-up was 7.8 years (2 months to 23.4 years). The disease-specific survival was 82% at five years, 57% at ten years and 45% at 15 years. The local recurrence-free survival was 49% at five years, 37% at ten years and 20% at 15 years. Local recurrence occurred in 30 patients (56%) at a mean of 3.8 years (3 months to 13 years) post-operatively. Survival after the treatment of recurrence was 89% at two years, 56% at five years and 19% at ten years. Of nine patients who had complete resection of a recurrence, one died after 72 months and eight remain disease-free. Incomplete resection of recurrent disease resulted in a survival of 54% at two years and 36% at five years. For 12 patients with a local recurrence who were treated palliatively, survival was 81% at two years and 31% at five years. A wide margin of resection gave the best chance of long-term survival and complete resection of local recurrence the best chance of control of disease. Cite this article: Bone Joint J 2015;97-B:711–15

Aims. There is a lack of evidence about the risk factors for local recurrence of a giant cell tumour (GCT) of the sacrum treated with nerve-sparing surgery, probably because of the rarity of the disease. This study aimed to answer two questions: first, what is the rate of local recurrence of sacral GCT treated with nerve-sparing surgery and second, what are the risk factors for its local recurrence?. Methods. A total of 114 patients with a sacral GCT who underwent nerve-sparing surgery at our hospital between July 2005 and August 2017 were reviewed. The rate of local recurrence was determined, and Kaplan-Meier survival analysis carried out to evaluate the mean recurrence-free survival. Possible risks factors including demographics, tumour characteristics, adjuvant therapy, operation, and laboratory indices were analyzed using univariate analysis. Variables with p < 0.100 in the univariate analysis were further considered in a multivariate Cox regression analysis to identify the risk factors. Results. The rate of local recurrence of sacral GCT treated with nerve-sparing surgery was 28.95% (33/114). Multivariate Cox regression analysis showed that large tumour size (> 8.80 cm) (hazard ratio (HR) 3.16; 95% confidence interval (CI) 1.27 to 7.87; p = 0.014), high neutrophil-to-lymphocyte ratio (NLR) (> 2.09) (HR 3.13; 95% CI 1.28 to 7.62; p = 0.012), involvement of a sacroiliac joint (HR 3.09; 95% CI 1.06 to 9.04; p = 0.039), and massive intraoperative blood loss (> 1,550 ml) (HR 2.47; 95% CI 1.14 to 5.36; p = 0.022) were independent risk factors for local recurrence. Conclusion. Patients with a sacral GCT who undergo nerve-sparing surgery have a local recurrence rate of 29%. Large tumour size, high NLR, involvement of a sacroiliac joint, and massive intraoperative blood loss are independent risk factors. Cite this article: Bone Joint J 2020;102-B(10):1392–1398

Aims. The aim of this paper was to investigate the prognostic factors for local recurrence in patients with pathological fracture through giant cell tumours of bone (GCTB). Patients and Methods. A total of 107 patients presenting with fractures through GCTB treated at our institution (Royal Orthopaedic Hospital, Birmingham, United Kingdom) between 1995 and 2016 were retrospectively studied. Of these patients, 57 were female (53%) and 50 were male (47%).The mean age at diagnosis was 33 years (14 to 86). A univariate analysis was performed, followed by multivariate analysis to identify risk factors based on the treatment and clinical characteristics. Results. The initial surgical treatment was curettage with or without adjuvants in 55 patients (51%), en bloc resection with or without reconstruction in 45 patients (42%), and neoadjuvant denosumab, followed by resection (n = 3, 3%) or curettage (n = 4, 4%). The choice of treatment depended on tumour location, Campanacci tumour staging, intra-articular involvement, and fracture displacement. Neoadjuvant denosumab was used only in fractures through Campanacci stage 3 tumours. Local recurrence occurred in 28 patients (25%). Surgery more than six weeks after the fracture did not affect the risk of recurrence in any of the groups. In Campanacci stage 3 tumours not treated with denosumab, en bloc resection had lower local recurrences (13%), compared with curettage (39%). In tumours classified as Campanacci 2, intralesional curettage and en bloc resections had similar recurrence rates (21% and 24%, respectively). After univariate analysis, the type of surgical intervention, location, and the use of denosumab were independent factors predicting local recurrence. Further surgery was required 33% more often after intralesional curettage in comparison with resections (mean 1.59, 0 to 5 vs 1.06, 0 to 3 operations). All patients treated with denosumab followed by intralesional curettage developed local recurrence. Conclusion. In patients with pathological fractures through GCTB not treated with denosumab, en bloc resection offers lower risks of local recurrence in tumours classified as Campanacci stage 3. Curettage or resections are both similar options in terms of the risk of local recurrence for tumours classified as Campanacci stage 2. The benefits of denosumab followed by intralesional curettage in these patients still remains unclear

Aims. Iliosacral sarcoma resections have been shown to have high rates of local recurrence (LR) and poor overall survival. There is also no universal classification for the resection of pelvic sarcomas invading the sacrum. This study proposes a novel classification system and analyzes the survival and risk of recurrence, when using this system. Methods. This is a retrospective analysis of 151 patients (with median follow-up in survivors of 44 months (interquartile range 12 to 77)) who underwent hemipelvectomy with iliosacral resection at a single centre between 2007 and 2019. The proposed classification differentiates the extent of iliosacral resection and defines types S1 to S6 (S1 resection medial and parallel to the sacroiliac joint, S2 resection through the ipsilateral sacral lateral mass to the neuroforamina, S3 resection through the ipsilateral neuroforamina, S4 resection through ipsilateral the spinal canal, and S5 and S6 contralateral sacral resections). Descriptive statistics and the chi-squared test were used for categorical variables, and the Kaplan-Meier survival analysis were performed. Results. Resections were S1 in 25/151 patients (17%), S2 in 70/151 (46%), S3 in 33/151 (22%), S4 in 77/151 (11%), S5 in 4/151 (3%), and S6 in 2/151 (1%). An internal hemipelvectomy was performed in 113/151 patients (75%), and 38/151 patients (25%) had an external hemipelvectomy. The predominant types of sarcoma were high-grade osteosarcoma in 48/151 patients (32%), chondrosarcoma in 41/151 (27%), Ewing sarcoma in 33/151 (22%), pleomorphic sarcoma in 17/151 (11%), and others in 2/151 (8%). LR was found in 24/151 patients (15%) with S3, S5, with S6 resections showing the highest rate of LR (p = 0.038). Overall, 19/151 patients (16%) had evidence of metastastic disease at the time of surgery and these patients showed poorer survival when compared to patients with no metastasis. Conclusion. The proposed classification can help to report and compare different surgical and reconstructive approaches in these difficult cases who are still have a considerable risk of LR. Cite this article: Bone Joint J 2022;104-B(2):290–296

Pigmented villonodular synovitis (PVNS) is a rare proliferative process of the synovium which most commonly affects the knee and occurs in either a localised (LPVNS) or a diffuse form (DPVNS). The effect of different methods of surgical synovectomy and adjuvant radiotherapy on the rate of recurrence is unclear. We conducted a systematic review and identified 35 observational studies in English which reported the use of surgical synovectomy to treat PVNS of the knee. A meta-analysis included 630 patients, 137 (21.8%) of whom had a recurrence after synovectomy. For patients with DPVNS, low-quality evidence found that the rate of recurrence was reduced by both open synovectomy (odds ration (OR) = 0.47; 95% CI 0.25 to 0.90; p = 0.024) and combined open and arthroscopic synovectomy (OR = 0.19, 95% CI = 0.06 to 0.58; p = 0.003) compared with arthroscopic surgery. Very low-quality evidence found that the rate of recurrence of DPVNS was reduced by peri-operative radiotherapy (OR = 0.31, 95% CI 0.14 to 0.70; p = 0.01). Very low-quality evidence suggested that the rate of recurrence of LPVNS was not related to the surgical approach. . This meta-analysis suggests that open synovectomy or synovectomy combined with peri-operative radiotherapy for DPVNS is associated with a reduced rate of recurrence. Large long-term prospective multicentre observational studies, with a focus on both rate of recurrence and function, are required to confirm these findings. Cite this article: Bone Joint J 2015;97-B:550–7

We investigated whether the presence of a pathological fracture increased the risk of local recurrence in patients with a giant cell tumour (GCT) of bone. We also assessed if curettage is still an appropriate form of treatment in the presence of a pathological fracture. We conducted a comprehensive review and meta-analysis of papers which reported outcomes in patients with a GCT with and without a pathological fracture at presentation. We computed the odds ratio (OR) of local recurrence in those with and without a pathological fracture. . We selected 19 eligible papers for final analysis. This included 3215 patients, of whom 580 (18.0%) had a pathological fracture. The pooled OR for local recurrence between patients with and without a pathological fracture was 1.05 (95% confidence interval (CI) 0.66 to 1.67, p = 0.854). Amongst the subgroup of patients who were treated with curettage, the pooled OR for local recurrence was 1.23 (95% CI 0.75 to 2.01, p = 0.417). . A post hoc sample size calculation showed adequate power for both comparisons. . There is no difference in local recurrence rates between patients who have a GCT of bone with and without a pathological fracture at the time of presentation. The presence of a pathological fracture should not preclude the decision to perform curettage as carefully selected patients who undergo curettage can have similar outcomes in terms of local recurrence to those without such a fracture. Cite this article: Bone Joint J 2015;97-B:1566–71

We have investigated the significance of local recurrence on survival in 173 patients with localised soft-tissue sarcomas of the limbs and of the trunk. The overall survival rates at five and ten years were 75.2% and 68.0%, respectively. After definitive surgery at our hospitals, there was local recurrence in 25 patients (14.5%). After inadequate operations elsewhere, there was a higher incidence of late local recurrence (28.3%), in comparison with those with primary tumours treated by us (9.0%), or patients referred to us immediately after inadequate surgery elsewhere (10.2%). Because of small numbers these differences in the survival rates were not statistically significantly different. Univariate survival analysis showed that local recurrence after definitive surgery (p = 0.006) together with the histological grade (p = 0.0002), the size of the tumour (p = 0.002), its depth in relation to deep fascia (p = 0.003), and the surgical margin (p = 0.0001) were the significant prognostic factors. Local recurrence at the initial presentation did not affect survival. Multivariate analysis showed that local recurrence after definitive surgery also lost its apparent prognostic significance

We retrospectively studied local recurrence of giant cell tumour in long bones following treatment with curettage and cementing in 137 patients. The median follow-up time was 60 months (3 to 166). A total of 19 patients (14%) had at least one local recurrence, the first was diagnosed at a median of 17 months (3 to 29) after treatment of the primary tumour. There were 13 patients with a total of 15 local recurrences who were successfully treated by further curettage and cementing. Two patients with a second local recurrence were consequently treated twice. At the last follow-up, at a median of 53 months (3 to 128) after the most recent operation, all patients were free from disease and had good function. We concluded that local recurrence of giant cell tumour after curettage and cementing in long bones can generally be successfully treated with further curettage and cementing, with only a minor risk of increased morbidity. This suggests that more extensive surgery for the primary tumour in an attempt to obtain wide margins is not the method of choice, since it leaves the patient with higher morbidity with no significant gain with respect to cure of the disease

We have reviewed 13 operations on 11 patients using curettage and polymethylmethacrylate cement for giant-cell tumour of bone (GCT) to assess the value of radiology in the early detection of recurrence. There were four recurrences, the most specific radiological sign on plain radiography was lysis of 5 mm or more at the cement-bone interface. This preceded clinical signs by a mean of four months and was identified at a mean of 3.75 months after operation. There was not always a complete sclerotic margin around the cement, but when it was present, there was never evidence of recurrence. MRI was helpful in assessing cases with evidence of recurrence. Frequent surveillance with plain radiography should continue for one year after operation irrespective of clinical signs of recurrence. When the appearance of the plain radiographs suggests recurrence, MRI should be performed and followed by image-guided needle biopsy

We considered whether a positive margin occurring after resection of a soft-tissue sarcoma of a limb would affect the incidence of local recurrence. Patients with low-grade liposarcomas were expected to be a low-risk group as were those who had positive margins planned before surgery to preserve critical structures. Two groups, however, were expected to be at a higher risk, namely, patients who had undergone unplanned excision elsewhere with a positive margin on re-excision and those with unplanned positive margins occurring during primary resection. Of 566 patients in a prospective database, 87 with positive margins after limb-sparing surgery and adjuvant radiotherapy were grouped according to the clinical scenario by an observer blinded to the outcome. The rate of local recurrence differed significantly between the two low- (4.2% and 3.6%) and the two high-risk groups (31.6% and 37.5%). This classification therefore provides useful information about the incidence of local recurrence after positive-margin resection

Local recurrence along the biopsy track is a known complication of percutaneous needle biopsy of malignant musculoskeletal tumours. In order to completely excise the track with the tumour its identification is essential, but this becomes increasingly difficult over time. In an initial prospective study, 22 of 45 patients (48.8%) identified over a three-month period, treated by resection of a musculoskeletal tumour, had an unidentifiable biopsy site at operation, with identification statistically more difficult after 50 days. We therefore introduced the practice of marking the biopsy site with India ink. In all 55 patients undergoing this procedure, the biopsy track was identified pre-operatively (100%); this difference was statistically significant. We recommend this technique as a safe, easy and accurate means of ensuring adequate excision of the biopsy track. Cite this article: Bone Joint J 2013;95-B:250–3

Aims. Tenosynovial giant cell tumour (TGCT) is a rare benign tumour of the musculoskeletal system. Surgical management is fraught with challenges due to high recurrence rates. The aim of this study was to describe surgical treatment and evaluate surgical outcomes of TGCT at an Australian tertiary referral centre for musculoskeletal tumours and to identify factors affecting recurrence rates. Methods. A prospective database of all patients with TGCT surgically managed by two orthopaedic oncology surgeons was reviewed. All cases irrespective of previous treatment were included and patients without follow-up were excluded. Pertinent tumour characteristics and surgical outcomes were collected for analysis. Results. There were 111 total cases included in the study; 71 (64%) were female, the mean age was 36 years (SD 13.6), and the knee (n = 64; 57.7%) was the most commonly affected joint. In all, 60 patients (54.1%) had diffuse-type (D-TGCT) disease, and 94 patients (84.7%) presented therapy-naïve as "primary cases" (PC). The overall recurrence rate was 46.8% for TGCT. There was a statistically significant difference in recurrence rates between D-TGCT and localized disease (75.0% vs 13.7%, relative risk (RR) 3.40, 95% confidence interval (CI) 2.17 to 5.34; p < 0.001), and for those who were referred in the ”revision cases” (RC) group compared to the PC group (82.4% vs 48.9%, RR 1.68, 95% CI 1.24 to 2.28; p = 0.011). Age, sex, tumour volume, and mean duration of symptoms were not associated with recurrence (p > 0.05). Conclusion. Recurrence rates remain high even at a tertiary referral hospital. Highest rates are seen in D-TGCT and “revision cases”. Due to the risks of recurrence, the complexity of surgery, and the need for adjuvant therapy, this paper further supports the management of TGCT in a tertiary referral multi-disciplinary orthopaedic oncology service. Cite this article: Bone Jt Open 2023;4(11):846–852

Aims. The scapula is a rare site for a primary bone tumour. Only a small number of series have studied patient outcomes after treatment. Previous studies have shown a high rate of recurrence, with functional outcomes determined by the preservation of the glenohumeral joint and deltoid. The purpose of the current study was to report the outcome of patients who had undergone tumour resection that included the scapula. Methods. We reviewed 61 patients (37 male, 24 female; mean age 42 years (SD 19)) who had undergone resection of the scapula. The most common resection was type 2 (n = 34) according to the Tikhoff-Linberg classification, or type S1A (n = 35) on the Enneking classification. Results. The ten-year disease-specific survival was 76%. High tumour grade (hazard ratio (HR) 4.27; p = 0.016) and a total resection of the scapula (HR 3.84; p = 0.015) were associated with worse survival. The ten-year metastasis-free and local recurrence-free survivals were 82% and 86%, respectively. Total scapular resection (HR 6.29; p = 0.004) was associated with metastatic disease and positive margins were associated with local recurrence (HR 12.86; p = 0.001). At final follow-up, the mean shoulder forward elevation and external rotation were 79° (SD 62°) and 27° (SD 25°), respectively. The most recent functional outcomes evaluated included the mean Musculoskeletal Tumor Society Score (76% (SD 17%)), the American Shoulder and Elbow Score (73% (SD 20%)), and the Simple Shoulder Test (7 (SD 3)). Preservation of the glenoid (p = 0.001) and scapular spine (p < 0.001) improved clinical outcomes; interestingly, preservation of the scapular spine without the glenoid improved outcomes (p < 0.001) compared to preservation of the glenoid alone (p = 0.05). Conclusion. Resection of the scapula is a major undertaking with an oncological outcome related to tumour grade, and a functional outcome associated with the status of the scapular spine and glenoid. Positive resection margins are associated with local recurrence. Cite this article: Bone Joint J 2023;105-B(12):1314–1320

Aims. Giant cell tumour of bone (GCTB) is a locally aggressive lesion that is difficult to treat as salvaging the joint can be associated with a high rate of local recurrence (LR). We evaluated the risk factors for tumour relapse after treatment of a GCTB of the limbs. Methods. A total of 354 consecutive patients with a GCTB underwent joint salvage by curettage and reconstruction with bone graft and/or cement or en bloc resection. Patient, tumour, and treatment factors were analyzed for their impact on LR. Patients treated with denosumab were excluded. Results. There were 53 LRs (15%) at a mean 30.5 months (5 to 116). LR was higher after curettage (18.4%) than after resection (4.6%; p = 0.008). Neither pathological fracture (p = 0.240), Campanacci grade (p = 0.734), soft-tissue extension (p = 0.297), or tumour size (p = 0.872) affected the risk of recurrence. Joint salvage was possible in 74% of patients overall (262/354), and 98% after curettage alone (262/267). Of 49 patients with LR after curettage, 44 (90%) underwent repeated curettage and joint salvage. For patients treated by curettage, only age less than 30 years (p = 0.042) and location in the distal radius (p = 0.043) predicted higher LR. The rate of LR did not differ whether cement or bone graft was used (p = 0.753), but may have been reduced by the use of hydrogen peroxide (p = 0.069). Complications occurred in 15.3% of cases (54/354) and did not differ by treatment. Conclusion. Most patients with a GCTB can undergo successful joint salvage by aggressive curettage, even in the presence of a soft-tissue mass, pathological fracture, or a large lesion, with an 18.4% risk of local recurrence. However, 90% of local relapses after curettage can be treated by repeat joint salvage. Maximizing joint salvage is important to optimize long-term function since most patients with a GCTB are young adults. Younger patients and those with distal radius tumours treated with joint-sparing procedures have a higher rate of local relapse and may require more aggressive treatment and closer follow-up. Cite this article: Bone Joint J 2023;105-B(5):559–567

Aims. The present study investigated receptor activator of nuclear factor kappa-Β ligand (RANKL), osteoprotegerin (OPG), and Runt-related transcription factor 2 (RUNX2) gene expressions in giant cell tumour of bone (GCTB) patients in relationship with tumour recurrence. We also aimed to investigate the influence of CpG methylation on the transcriptional levels of RANKL and OPG. Methods. A total of 32 GCTB tissue samples were analyzed, and the expression of RANKL, OPG, and RUNX2 was evaluated by quantitative polymerase chain reaction (qPCR). The methylation status of RANKL and OPG was also evaluated by quantitative methylation-specific polymerase chain reaction (qMSP). Results. We found that RANKL and RUNX2 gene expression was upregulated more in recurrent than in non-recurrent GCTB tissues, while OPG gene expression was downregulated more in recurrent than in non-recurrent GCTB tissues. Additionally, we proved that changes in DNA methylation contribute to upregulating the expression of RANKL and downregulating the expression of OPG, which are critical for bone homeostasis and GCTB development. Conclusion. Our results suggest that the overexpression of RANKL/RUNX2 and the lower expression of OPG are associated with recurrence in GCTB patients. Cite this article: Bone Joint Res 2024;13(2):84–91

Aims. The epiphyseal approach to a chondroblastoma of the intercondylar notch of a child’s distal femur does not provide adequate exposure, thereby necessitating the removal of a substantial amount of unaffected bone to expose the lesion. In this study, we compared the functional outcomes, local recurrence, and surgical complications of treating a chondroblastoma of the distal femoral epiphysis by either an intercondylar or an epiphyseal approach. Methods. A total of 30 children with a chondroblastoma of the distal femur who had been treated by intraregional curettage and bone grafting were retrospectively reviewed. An intercondylar approach was used in 16 patients (group A) and an epiphyseal approach in 14 (group B). Limb function was assessed using the Musculoskeletal Tumor Society (MSTS) scoring system and Sailhan’s functional criteria. Results. At final follow-up, the mean MSTS score was 29.1 (SD 0.9) in group A and 26.7 (SD 1.5) in group B (p = 0.006). According to Sailhan’s criteria, the knee function was good and fair in 14 (87.5%) and two (12.5%) patients of group A, and eight (57.1%) and six (42.9%) patients of group B, respectively (p = 0.062). The lesion had recurred in one patient (6.2%) in group A and four patients (28.6%) in group B. Limb shortening > 1 cm was recorded in one patient (6.2%) from group A and six patients (42.8%) from group B. Joint degeneration was noted in one patient from group A and three patients from group B. Conclusion. An intercondylar approach to a chondroblastoma of the middle two-quarters of the distal femoral epiphysis results in better outcomes than a medial or lateral epiphyseal approach: specifically, better limb function, a lower rate of recurrence, and a lower rate of physeal damage and joint degeneration. Cite this article: Bone Joint J 2024;106-B(2):195–202

Aims. The ulna is an extremely rare location for primary bone tumours of the elbow in paediatrics. Although several reconstruction options are available, the optimal reconstruction method is still unknown due to the rarity of proximal ulna tumours. In this study, we report the outcomes of osteoarticular ulna allograft for the reconstruction of proximal ulna tumours. Methods. Medical profiles of 13 patients, who between March 2004 and November 2021 underwent osteoarticular ulna allograft reconstruction after the resection of the proximal ulna tumour, were retrospectively reviewed. The outcomes were measured clinically by the assessment of elbow range of motion (ROM), stability, and function, and radiologically by the assessment of allograft-host junction union, recurrence, and joint degeneration. The elbow function was assessed objectively by the Musculoskeletal Tumor Society (MSTS) score and subjectively by the Toronto Extremity Salvage Score (TESS) and Mayo Elbow Performance Score (MEPS) questionnaire. Results. The mean follow-up of patients was 60.3 months (SD 28.5). The mean elbow flexion-extension ROM was 95.8° (SD 21). The mean MSTS of the patients was 84.4 (SD 8.2), the mean TESS was 83.8 (SD 6.7), and the mean MEPS was 79.2 (SD 11.5). All the patients had radiological union at the osteotomy site. Symptomatic osteoarthritic change was observed in three patients (23%), one of whom ended up with elbow joint fusion. Two patients (15.4%) had recurrence during the follow-up period. Surgical complications included two allograft fractures, two plate fractures, three medial instabilities, and two infections. Conclusion. Osteoarticular ulna allograft reconstruction provides acceptable functional outcomes. Despite a high rate of complications, it is still a valuable reconstruction method, particularly in skeletally immature patients who need their distal humerus physis for the rest of hand growth. Cite this article: Bone Jt Open 2024;5(9):749–757

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. Low-grade central osteosarcoma (LGCOS), a rare type of osteosarcoma, often has misleading radiological and pathological features that overlap with those of other bone tumours, thereby complicating diagnosis and treatment. We aimed to analyze the clinical, radiological, and pathological features of patients with LGCOS, with a focus on diagnosis, treatment, and outcomes. Methods. We retrospectively analyzed the medical records of 49 patients with LGCOS (Broder’s grade 1 to 2) treated between January 1985 and December 2017 in a single institute. We examined the presence of malignant features on imaging (periosteal reaction, cortical destruction, soft-tissue invasion), the diagnostic accuracy of biopsy, surgical treatment, and oncological outcome. Results. Based on imaging, 35 of 49 patients (71.4%) exhibited malignant features. Overall, 40 of 49 patients (81.6%) had undergone a biopsy before en-bloc resection: 27 of 40 patients (67.5%) were diagnosed on the first biopsy, which was more accurate when carried out by open rather than needle biopsy (91.3% vs 35.3% diagnostic accuracy, respectively; p < 0.001). Of the 40 patients treated by en-bloc resection, surgical margins were wide in 38 (95.0%) and marginal in two (5.0%). Furthermore, nine of 49 patients (18.4%) underwent curettage (intralesional margin) without previous biopsy. All patients with a positive margin developed local recurrence. Distant metastases occurred in five of 49 patients (10.2%). The mean five-year overall survival (OS) and distant relapse-free survival (D-RFS) were 89.3% (SD 5.1%) and 85.7% (SD 5.5%), respectively. Univariate analysis showed that the occurrence of distant metastasis was a poor prognostic factor for OS (hazard ratio 11.54, 95% confidence interval (CI) 1.92 to 69.17; p < 0.001). Local recurrence was a poor prognostic factor for D-RFS (HR 8.72, 95% CI 1.69 to 45.0; p = 0.002). Conclusion. The diagnosis of LGCOS can be challenging because it may present with non-malignant features and has a low diagnostic accuracy on biopsy. If precisely diagnosed, LGCOS can be successfully treated by surgical excision with wide margins. Cite this article: Bone Joint J 2024;106-B(1):99–106

Aims. Clear cell sarcoma (CCS) of soft-tissue is a rare melanocytic subtype of mesenchymal malignancy. The aim of this study was to investigate the clinical and therapeutic factors associated with increased survival, stratified by clinical stage, in order to determine the optimal treatment. Methods. The study was a retrospective analysis involving 117 patients with histologically confirmed CCS, between July 2016 and November 2017, who were enrolled in the Bone and Soft Tissue Tumour Registry in Japan. Results. The five- and ten-year survival rates were 41% (95% confidence interval (CI) 29 to 52) and 37% (95% CI 25 to 49), respectively. On multivariable analysis, the size of the tumour of > 10 cm (p = 0.006), lymph node metastasis at the time of diagnosis (p < 0.001), distant metastases at the time of diagnosis (p < 0.001), and no surgery for the primary tumour (p = 0.019) were independently associated with a poor survival. For N0M0 CCS (n = 68), the development of distant metastases was an independent prognostic factor for survival (early (< 12 months), hazard ratio (HR) 116.78 (95% CI 11.69 to 1,166.50); p < 0.001; late (> 12 months), HR 14.79 (95% CI 1.66 to 131.63); p = 0.016); neoadjuvant/adjuvant chemotherapy (p = 0.895) and/or radiotherapy (p = 0.216) were not significantly associated with survival. The five-year cumulative incidence of local recurrence was 19% (95% CI 8 to 35) and the size of the tumour was significantly associated with an increased rate of local recurrence (p = 0.012). For N1M0 CCS (n = 18), the risk of mortality was significantly lower in patients who underwent surgery for both the primary tumour and lymph node metastases (HR 0.03 (95% CI 0.00 to 0.56); p = 0.020). For M1 CCS (n = 31), excision of the primary tumour was independently associated with better survival (HR 0.26 (95% CI 0.09 to 0.76); p = 0.013). There was no significant difference in survival between the different types of systemic treatment (p = 0.523). Conclusion. Complete excision of the primary tumour and lymph nodes is associated with a better survival in patients with CCS. Systemic treatment appears to provide limited benefits, demonstrating a pressing need for novel systemic agents. Cite this article: Bone Joint J 2023;105-B(11):1216–1225