Purpose

We hypothesized that the intra-operative measurement of the femoral head may increase the accuracy of the acetabular cup size optimal selection in total hip arthroplasty (THA). The purpose of this clinical research was to analyze the correlation between the estimated cup size from intra-operative measurement of the femoral head and the pre-operative templated cup size.

Methods

A prospective observational single-center study was conducted from June 2019 to January 2020 including primary THA (n = 100). All cases were pre-operatively templated. The measurement of the anterior–posterior diameter of the femoral head was routinely intra-operatively performed. Any definitive implanted cup was considered as “oversized” when the size was > 4 mm than the diameter of the native head.

Results

The median (interquartile range) size of the implanted cup, pre-operative planned cup size, and diameter of the femoral head were measured 52 (50–54) mm, 50 (48–54) mm and 49 (45–51) mm, respectively. Pre-operative planned size cup accurately predicted the implanted cup or differed in only one size (2 mm) in 77 (78%) cases. Otherwise, intra-operative femoral head measurement method accurately predicted the implanted or differed in only one size (2 mm) in 51 (87%) cases (p = 0.097).

Conclusion

The intra-operative femoral head measurement is a simple and reliable tool to help the surgeons choose the best size of the acetabular cup and is as reliable as the pre-operative templating in order to avoid cup oversizing in THA. Utmost caution is warranted whenever the cup reamer is > 4 mm than the anterior–posterior diameter of the native head.

中文翻译：

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术中测量股骨头直径能否帮助外科医生选择最佳尺寸的髋臼杯？

目的

我们假设股骨头的术中测量可能会提高全髋关节置换术 (THA) 中髋臼杯尺寸最佳选择的准确性。本临床研究的目的是分析术中测量股骨头的估计杯尺寸与术前模板杯尺寸之间的相关性。

方法

2019 年 6 月至 2020 年 1 月进行了一项前瞻性观察性单中心研究，包括初次全髋关节置换 ( n  = 100)。所有病例都在术前进行了模板化。术中常规测量股骨头前后径。当尺寸比原生头的直径 > 4 毫米时，任何确定的植入杯都被认为是“超大”。

结果

植入的臼杯、术前计划的臼杯尺寸和股骨头直径的中位数（四分位距）测量值分别为 52 (50–54) mm、50 (48–54) mm 和 49 (45–51) mm ， 分别。在 77 (78%) 例中，术前计划尺寸的罩杯准确地预测了植入的罩杯或仅在一个尺寸 (2 mm) 上有所不同。否则，在 51 例 (87%) 病例中，术中股骨头测量方法准确地预测了植入物或只有一种尺寸 (2 mm) 存在差异 ( p  = 0.097)。

结论

术中股骨头测量是一种简单可靠的工具，可帮助外科医生选择最佳尺寸的髋臼杯，并且与术前模板一样可靠，以避免 THA 中杯过大。当臼杯铰刀比原生头部的前后直径 > 4 mm 时，需要格外小心。