Aims. Treatment of high-grade limb bone sarcoma that invades a joint requires en bloc extra-articular excision. MRI can demonstrate joint invasion but is frequently inconclusive, and its predictive value is unknown. We evaluated the diagnostic accuracy of direct and indirect radiological signs of intra-articular tumour extension and the performance characteristics of MRI findings of intra-articular tumour extension. Methods. We performed a retrospective case-control study of patients who underwent extra-articular excision for sarcoma of the knee, hip, or shoulder from 1 June 2000 to 1 November 2020. Radiologists blinded to the pathology results evaluated preoperative MRI for three direct signs of joint invasion (capsular disruption, cortical breach, cartilage invasion) and indirect signs (e.g. joint effusion, synovial thickening). The discriminatory ability of MRI to detect intra-articular tumour extension was determined by receiver operating characteristic analysis. Results. Overall, 49 patients underwent extra-articular excision. The area under the curve (AUC) ranged from 0.65 to 0.76 for direct signs of joint invasion, and was 0.83 for all three combined. In all, 26 patients had only one to two direct signs of invasion, representing an equivocal result. In these patients, the AUC was 0.63 for joint effusion and 0.85 for synovial thickening. When direct signs and synovial thickening were combined, the AUC was 0.89. Conclusion. MRI provides excellent discrimination for determining intra-articular tumour extension when multiple direct signs of invasion are present. When MRI results are equivocal, assessment of synovial thickening increases MRI’s discriminatory ability to predict intra-articular joint extension. These results should be interpreted in the context of the study’s limitations. The inclusion of only extra-articular excisions enriched the sample for true positive cases. Direct signs likely varied with tumour histology and location. A larger, prospective study of periarticular bone sarcomas with spatial correlation of histological and radiological findings is needed to validate these results before their adoption in clinical practice. Cite this article: Bone Jt Open 2024;5(10):944–952

Aims. Surgical limb sparing for knee-bearing paediatric bone sarcoma is considered to have a clinically significant influence on postoperative function due to complications and leg-length discrepancies. However, researchers have not fully evaluated the long-term postoperative functional outcomes. Therefore, in this study, we aimed to elucidate the risk factors and long-term functional prognosis associated with paediatric limb-sparing surgery. Methods. We reviewed 40 patients aged under 14 years who underwent limb-sparing surgery for knee bone sarcoma (15 cases in the proximal tibia and 25 in the distal femur) between January 2000 and December 2013, and were followed up for a minimum of five years. A total of 35 patients underwent reconstruction using artificial materials, and five underwent biological reconstruction. We evaluated the patients’ postoperative complications, survival rate of reconstruction material, and limb, limb function, and leg-length discrepancy at the final follow-up, as well as the risk factors for each. Results. Complications were observed in 55% (22/40) of patients. The limb survival and reconstruction material rates at five and ten years were 95% and 91%, and 88% and 66%, respectively. Infection was the only risk factor in both survivals (p < 0.001, p = 0.019). In the 35 patients with limb preservation, the median International Society of Limb Salvage (ISOLS) score at the final follow-up was 80 (47% to 97%). Younger age (p = 0.027) and complications (p = 0.005) were poor prognostic factors. A negative correlation was found between age and leg-length discrepancy (R = −0.426; p = 0.011). The ISOLS scores were significantly lower in patients with a leg-length discrepancy of more than 5 cm (p = 0.005). Conclusion. Young age and complications were linked to an unfavourable functional prognosis. Leg-length correction was insufficient, especially in very young children, resulting in decreased function of the affected limb. Limb-sparing surgery for these children remains a considerable challenge. Cite this article: Bone Jt Open 2024;5(10):868–878

Aims

The modern prevalence of primary tumours causing metastatic bone disease is ill-defined in the oncological literature. Therefore, the purpose of this study is to identify the prevalence of primary tumours in the setting of metastatic bone disease, as well as reported rates of pathological fracture, postoperative complications, 90-day mortality, and 360-day mortality for each primary tumour subtype.