Department of Industrial Engineering, Alma Mater Studiorum - University of Bologna, Bologna, Italy.
Clinica Ortopedica e Traumatologica II, IRCCS Istituto Ortopedico Rizzoli, Bologna, Italy.
J Orthop Surg Res. 2024 Aug 29;19(1):520. doi: 10.1186/s13018-024-04944-0.
Commercially available osseointegrated devices for transfemoral amputees are limited in size and thus fail to meet the significant anatomical variability in the femoral medullary canal. This study aimed to develop a customized osseointegrated stem to better accommodate a variety of femoral anatomies in transfemoral amputees than off-the-shelf stems. Customization is expected to enhance cortical bone preservation and increase the stem-bone contact area, which are critical for the long-term stability and success of implants.
A customized stem (OsteoCustom) was designed based on the statistical shape variability of the medullary canal. The implantability of the OsteoCustom stem was tested via 70 computed tomography (CT) images of human femurs and compared to that of a commercial device (OFI-C) for two different resection levels. The evaluations included the volume of cortical bone removed and the percentage of stem-bone contact area for both resection levels. Statistical significance was analyzed using paired and unpaired t tests.
The OsteoCustom stem could be virtually implanted in all 70 femurs, while the OFI-C was unsuitable in 19 cases due to insufficient cortical thickness after implantation, further emphasizing its adaptability to varying anatomical conditions. The OsteoCustom stem preserved a greater volume of cortical bone than did the OFI-C. In fact, 42% less bone was removed at the proximal resection level (3.15 cm³ vs. 5.42 cm³, p ≤ 0.0001), and 33% less at the distal resection level (2.25 cm³ vs. 3.39 cm³, p = 0.003). The stem-bone contact area was also greater for the OsteoCustom stem, particularly at the distal resection level, showing a 20% increase in contact area (52.3% vs. 32.2%, p = 0.002) compared to that of the OFI-C.
The OsteoCustom stem performed better than the commercial stem by preserving more cortical bone and achieving a greater stem-bone contact area, especially at distal resection levels where the shape of the medullary canal exhibits more inter-subject variability. Optimal fit in the distal region is of paramount importance for ensuring the stability of osseointegrated implants. This study highlights the potential benefits of customized osseointegrated stems in accommodating a broader range of femoral anatomies, with enhanced fit in the medullary canal.
市面上可用于股骨截肢患者的整合式骨内植入物在尺寸上存在限制，无法满足股骨髓腔在解剖结构上的显著变化。本研究旨在开发定制化的整合式骨内植入物，使其更能适应股骨截肢患者的各种股骨解剖结构，优于市售的标准植入物。定制化预期可以更好地保留皮质骨，并增加植入物与骨骼的接触面积，这对植入物的长期稳定性和成功至关重要。
基于髓腔的统计形状变化，设计了定制化的植入物（OsteoCustom）。通过 70 个人类股骨的计算机断层扫描（CT）图像，对 OsteoCustom 植入物的可植入性进行了测试，并与两种不同切除水平的商业设备（OFI-C）进行了比较。评估包括两种切除水平的皮质骨去除量和植入物与骨骼的接触面积百分比。使用配对和非配对 t 检验进行了统计学意义分析。
OsteoCustom 植入物可以虚拟植入 70 个股骨中的所有骨骼，而 OFI-C 在 19 个病例中不适用，因为植入后皮质骨厚度不足，进一步强调了其对不同解剖结构条件的适应性。OsteoCustom 植入物保留的皮质骨体积大于 OFI-C。事实上，在近端切除水平，皮质骨去除量减少了 42%（3.15cm³比 5.42cm³，p≤0.0001），在远端切除水平，皮质骨去除量减少了 33%（2.25cm³比 3.39cm³，p=0.003）。OsteoCustom 植入物与骨骼的接触面积也更大，尤其是在远端切除水平，接触面积增加了 20%（52.3%比 32.2%，p=0.002），与 OFI-C 相比。
OsteoCustom 植入物的表现优于商业植入物，因为它保留了更多的皮质骨，并且与骨骼的接触面积更大，尤其是在远端切除水平，股骨髓腔的形状表现出更多的个体间变异性。在远端区域的最佳适配对于确保整合式骨内植入物的稳定性至关重要。本研究强调了定制化整合式骨内植入物在适应更广泛的股骨解剖结构方面的潜在优势，在髓腔中具有更好的适配性。
