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Purpose In vivo models are anatomically comparable to humans allowing to reproduce the patterns and progression of the disease and giving the opportunity to study the symptoms and responses to new treatments and materials. This study aimed to establish a valid and cost-effective in vivo rat model to assess the effects of implanted shoulder hemiarthroplasty materials on glenoid articular cartilage wear. Methods Eight adult male Wistar rats underwent right shoulder hemi-arthroplasty. A stainless steel metal bearing was used as a shoulder joint prosthesis. X-rays were performed one week after surgery to verify correct implant position. Additional X-rays were performed 30 and 60 days post-implantation. Animals were sacrificed 24 weeks after implantation. All specimens were evaluated with micro-CT for cartilage and bone wear characteristics as well as histologically for signs of osteoarthritis. Samples were compared to the non-operated shoulders. Results All animals recovered and resumed normal cage activity. All X-rays demonstrated correct implant positioning except for one in which the implant was displaced. Histologic evaluation demonstrated arthritic changes in the implanted shoulder. Decreased Trabecular thickness and Trabecular Spacing were documented among the implanted parties (p < .05). Bone Mineral Density and Tissue Mineral Density were reduced in the operated shoulder although not significantly (p = .07). Conclusions This study demonstrated significant glenoid cartilage wearing in the operated shoulder. Furthermore, the presence of an intra-articular hemiarthroplasty implant diminished underlying glenoid bone quality. This novel, in vivo-model will enable researchers to test implant materials and their effects on cartilage and bone tissue in a cost-effective reproducible rat model.

Prostate cancer is a significant health concern for men, emphasizing the need for effective treatment strategies. Dose-escalated external beam radiotherapy shows promise in improving outcomes but presents challenges due to radiation effects on nearby structures, such as the rectum. Innovative techniques, including rectal spacers, have emerged to mitigate these effects. This study comprehensively assessed tissue responses following the implantation of the Bioprotect biodegradable fillable balloon as a rectal spacer in a rat model. Evaluation occurred at multiple time points (4, 26, and 52 weeks) post-implantation. Results revealed localized tissue responses consistent with the expected reaction to biodegradable materials, characterized by mild to moderate fibrotic reactions and encapsulation, underscoring the safety and biocompatibility of the balloon. Importantly, no other adverse events occurred, and the animals remained healthy throughout the study. These findings support its potential clinical utility in radiotherapy treatments to enhance patient outcomes and minimize long-term implant-related complications, serving as a benchmark for future similar studies and offering valuable insights for researchers in the field. In conclusion, the findings from this study highlight the safety, biocompatibility, and potential clinical applicability of the Bioprotect biodegradable fillable balloon as a promising rectal spacer in mitigating radiation-induced complications during prostate cancer radiotherapy.

IntroductionWide resections of periacetabular tumors create a sizeable bony defect that inevitably results in severe loss of function. Reconstruction of such defects usually requires using large metal implants, a feature associated with considerable surgery extension and complications. The aim of this study is to report resection with no reconstruction of the bony defect. In this retrospective study, we reviewed a consecutive series of 16 patients diagnosed with malignant periacetabular tumors and underwent en-bloc resection without reconstructing their remaining bone defect.MethodsRecords were reviewed of 16 consecutive patients diagnosed with malignant periacetabular tumors and underwent en-bloc resection without reconstructing their remaining bony defect. Measurements included: the duration of surgery, blood loss, hemoglobin levels and the need for blood transfusions, data on other hospitalization characteristics, and intraoperative and postoperative complications.ResultsSixteen patients with malignant periacetabular bone tumors and extensive bone destruction underwent wide periacetabular tumor resection with a mean follow-up of 75 months and a mean age of 53 years. The average HOOS score was 46 (range: 20 to 76), and the mean MSTS score was 13% (range: 0 to 15). The mean operative time was 4.1 h, and the mean blood loss was 1200 ml. At their most recent follow-up, patients had a mean shortening of their operated extremity of 4.8 cm, and all could ambulate with assisting devices.ConclusionWide resection of periacetabular tumors without reconstruction provides acceptable levels of function and was associated with shorter surgical time, less blood loss and fewer postoperative complications compared to resection with reconstruction. Therefore, this approach may be considered a viable surgical option in patients with an extensive malignant periacetabular.Level IIIRetrospective study.