Department of Orthopaedic Surgery, University Medical Centre, 5 Ljubljanska street, SLO-2000, Maribor, Slovenia.
Faculty of Mechanical Engineering, University of Maribor, 17 Smetanova street, SLO-2000, Maribor, Slovenia.
BMC Musculoskelet Disord. 2021 Apr 16;22(1):356. doi: 10.1186/s12891-021-04210-y.
Bi-modular stems were introduced in primary total hip arthroplasty (THA) to enable better control of the femoral offset, leg length, and hip stability. Despite numerous reports on modular femoral neck fractures, some designs are still marketed worldwide. While the risk factors for the sudden failure are multifactorial and mostly known, the timing of this new THA complication is not predictable by any means.
In this report, the literature regarding one of the most popular bi-modular stems with specific neck-stem coupling (oval Morse taper) is reviewed and illustrated with a case of bilateral modular neck fracture in a patient with idiopathic aseptic necrosis of femoral heads treated with primary bi-modular THA. Because of bilateral modular femoral neck fracture, which occurred 3 years on the left side and 20 years after implantation on the right side, the patient required a total of 6 revisions and 208 days of hospitalized care.
To our knowledge, this is the first report of bilateral modular neck fracture in a single patient. Even though the same surgeon performed both operations and used the same neck length and orientation, fractures occurred with a 17-year time difference after implantation. This shows that we cannot predict with certainty when a fracture might occur. Orthopaedic surgeons should use bi-modular stem designs for primary THA very cautiously.
双模块化柄被引入初次全髋关节置换术（THA）中，以更好地控制股骨偏心距、下肢长度和髋关节稳定性。尽管有许多关于模块化股骨颈骨折的报告，但某些设计仍在全球范围内销售。虽然导致突然失效的危险因素是多因素的，并且大多为人所知，但这种新的 THA 并发症的发生时间是无法预测的。
在本报告中，对最流行的一种双模块化柄进行了文献回顾，该柄具有特定的颈柄连接（椭圆形莫尔斯锥度），并通过一名接受初次双模块化 THA 治疗的特发性股骨头无菌性坏死患者双侧模块化颈骨折的病例进行了说明。由于左侧发生双侧模块化股骨颈骨折，3 年后又在右侧发生，该患者总共需要进行 6 次翻修和 208 天的住院治疗。
据我们所知，这是首例单例双侧模块化颈骨折的报告。尽管同一外科医生进行了这两次手术，并使用了相同的颈长和方向，但在植入后 17 年发生了骨折。这表明我们不能确定何时会发生骨折。骨科医生应非常谨慎地在初次 THA 中使用双模块化柄设计。
