Purpose With the ability to overcome specific anatomical and pathological challenges, 3D printing technology is setting itself as an important tool in patient-specific orthopaedics, delivering anatomical models, patient-specific instruments, and custom-made implants. One of the most demanding procedures in limb salvage surgery is the reconstruction of bony defects after tumour resection. Even though still limited in clinical practice, early results of the use of 3D technology are gradually revealing its potentially huge impact in bone tumour surgery. Here, we present a case series illustrating our experience with the use of 3D printing technology in the reconstruction of bone defects after tumour resection, and its impact on cosmesis and quality of life. Methods We performed a retrospective analysis of 11 patients in whom a custom-made 3D-printed prosthesis was used to reconstruct a bone defect after resection for a bone tumour. Ten out of 11 patients were children (aged between 5 and 16 years) with osteosarcoma or Ewing sarcoma of the pelvis (2 children) or the arm (8 children), and one patient was a 67-year-old lady with a chondrosarcoma of the pelvis. All underwent wide resections resulting in considerable bone defects necessitating further reconstruction. Results Custom-made implants were extremely useful both in reconstruction of bone defects and in terms of cosmesis, recovery facilitation, and quality of life. In this respect, pelvic and humeral reconstructions with 3D-printed custom implants particularly showed a great potential. The mean follow-up was 33 months. Four patients died of disease (36%) and overall the major and minor complication rate was 54% (6 out of 11 patients). Three patients had implant dislocation (27% [3/11 cases]), one had legcompartment syndrome, and one patient reported limited range of motion. Only two out of 11 patients developed local recurrence. Conclusion Use of 3D customized implant helped us achieve two major goals in orthopaedic oncology-clear surgical resection and functional recovery with a good quality of life. Large studies with long-term follow-up are needed to reveal the value and future of 3D printing in orthopaedic oncology.

BackgroundOsteoid osteoma is a painful benign skeletal tumour of unknown aetiology. Most often it occurs in the long bones of extremities and responds well to nonsteroidal anti-inflammatory medications. However, unusual localization and atypical presentation of this tumour might present a diagnostic challenge, especially if symptoms mimic that indicative of juvenile spondyloarthritis.Case presentationA misdiagnosed ten-and-a-half-year-old girl with osteoid osteoma involving the distal phalanx of a little finger is presented. Her initial symptoms were pain and swelling of the little finger resembling dactylitis, while various imaging modalities showed signs of tenosynovitis, indicating a possible development of juvenile spondyloarthritis. Several trials of different non-steroid anti-inflammatory drugs gave no satisfactory results and ultrasound guided triamcinolone-hexacetonide injection provided only a short relief. Finally, almost three years after initial presentation, persistent clinical symptoms warranted repeated imaging that raised suspicion of an osteoid osteoma. Directed treatment with surgical intervention led to almost immediate and complete resolution of her symptoms.ConclusionsOsteoid osteoma should be suspected in case of a tender swelling of a digit in children and adolescents, regardless of initial imaging findings and clinical presentation. Early diagnosis and treatment of this benign condition can have a substantial impact on quality of life of patients and their families and protect them from many unnecessary diagnostic procedures and treatment.Electronic supplementary materialThe online version of this article (10.1186/s12891-018-2383-1) contains supplementary material, which is available to authorized users.

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