Sanki Tomoaki, Tetsunaga Tomonori, Furumatsu Takayuki, Yamada Kazuki, Kawamura Yoshi, Ozaki Toshifumi
Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences.
Acta Med Okayama. 2021 Feb;75(1):71-77. doi: 10.18926/AMO/61437.
Intra-operative acetabular fracture is a total hip arthroplasty complication that can occur during cementless cup insertion, especially in osteoporotic patients. We conducted this biomechanical study to investigate the impact resistance of the acetabulum with simulated bones of different density by drop-weight impact testing. Low- and high-density polyurethane foam blocks were used as osteoporotic and healthy bone models, respectively. Polyurethane blocks were used as the acetabular cancellous bone. Composite sheets were used as the acetabu-lum's medial cortex. The testing revealed that the osteoporotic bone model's impact resistance was significantly lower than that the healthy bone model'. In the healthy bone model, even thin acetabular cancellous bone with ≥ 1 mm acetabulum medial cortex was less likely to fracture. In the osteoporotic bone model, fracture was pos-sible without ≥ 1 mm medial cortex of the acetabulum and thick acetabular cancellous bone. Although impac-tion resistance differs due to bone quality, the impaction resistance in this osteoporotic bone model was equiv-alent to that healthy bone model's when a thick medial wall was present. To avoid intra-operative acetabulum fracture, surgeons should consider both the bone quality and the thicknesses of the medial cortex and acetabu-lar cancellous bone.
术中髋臼骨折是全髋关节置换术的一种并发症，可发生在非骨水泥髋臼杯植入过程中，尤其是在骨质疏松患者中。我们进行了这项生物力学研究，通过落锤冲击试验，使用不同密度的模拟骨来研究髋臼的抗冲击性。分别使用低密度和高密度聚氨酯泡沫块作为骨质疏松和健康骨模型。聚氨酯块用作髋臼松质骨。复合片用作髋臼内侧皮质。测试表明，骨质疏松骨模型的抗冲击性明显低于健康骨模型。在健康骨模型中，即使髋臼内侧皮质厚度≥1mm的薄髋臼松质骨也不太可能骨折。在骨质疏松骨模型中，髋臼内侧皮质厚度不足1mm且髋臼松质骨较薄时就有可能发生骨折。尽管抗冲击性因骨质不同而有所差异，但当存在较厚的内侧壁时，该骨质疏松骨模型的抗冲击性与健康骨模型相当。为避免术中髋臼骨折，外科医生应同时考虑骨质以及髋臼内侧皮质和髋臼松质骨的厚度。
