Objective

To compare computer-based 3D-analysis for quantification of the femorotibial joint space width (JSW) using weight-bearing cone beam CT (WB-CT), non-weight-bearing multi-detector CT (NWB-CT), and weight-bearing conventional radiographs (WB-XR).

Design

Twenty-six participants prospectively underwent NWB-CT, WB-CT, and WB-XR of the knee. For WB-CT and NWB-CT, the average and minimal JSW was quantified by 3D-analysis of the minimal distance of any point of the subchondral tibial bone surface and the femur. Associations with mechanical leg axes and osteoarthritis were evaluated. Minimal JSW of WB-CT was further compared to WB-XR. Two-tailed p-values of <0.05 were considered significant.

Results

Significant differences existed of the average medial and lateral JSW between WB-CT and NWB-CT (medial: 4.7 vs 5.1 mm [P = 0.028], lateral: 6.3 vs 6.8 mm [P = 0.008]). The minimal JSW on WB-XR (medial:3.1 mm, lateral:5.8 mm) were significantly wider compared to WB-CT and NWB-CT (both medial:1.8 mm, lateral:2.9 mm, all p < 0.001), but not significantly different between WB-CT and NWB-CT (all p ≥ 0.869). Significant differences between WB-CT and NWB-CT existed in participants with varus knee alignment for the average and the minimal medial JSW (p = 0.004 and p = 0.011) and for participants with valgus alignment for the average lateral JSW (p = 0.013). On WB-CT, 25% of the femorotibial compartments showed bone-on-bone apposition, which was significantly higher when compared to NWB-CT (10%,P = 0.008) and WB-XR (8%,P = 0.012).

Conclusion

Combining WB-CT with 3D-based assessment allows detailed quantification of the femorotibial joint space and the effect of knee alignment on JSW. WB-CT demonstrates significantly more bone-on-bone appositions, which are underestimated or even undetectable on NWB-CT and WB-XR.

中文翻译：

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负重CT量化膝关节间隙宽度的三维分析：与非负重CT和负重X线摄影的比较

客观的

比较使用负重锥形束 CT (WB-CT)、非负重多探测器 CT (NWB-CT) 和负重-股胫关节间隙宽度 (JSW) 的计算机 3D 分析轴承常规射线照片（WB-XR）。

设计

26 名参与者前瞻性地接受了膝关节的 NWB-CT、WB-CT 和 WB-XR。对于 WB-CT 和 NWB-CT，平均和最小 JSW 通过 3D 分析对胫骨下骨表面和股骨的任何点的最小距离进行量化。评估与机械腿轴和骨关节炎的关联。进一步比较了 WB-CT 的最小 JSW 与 WB-XR。<0.05的双尾p值被认为是显着的。

结果

WB-CT 和 NWB-CT 之间的平均内侧和外侧 JSW 存在显着差异（内侧：4.7 vs 5.1 mm [ P  = 0.028]，外侧：6.3 vs 6.8 mm [ P  = 0.008]）。与 WB-CT 和 NWB-CT 相比，WB-XR 上的最小 JSW（内侧：3.1 mm，外侧：5.8 mm）明显更宽（内侧：1.8 mm，外侧：2.9 mm，所有p  < 0.001），但不是WB-CT 和 NWB-CT 之间存在显着差异（所有p  ≥ 0.869）。WB-CT 和 NWB-CT 之间存在显着差异，在平均和最小内侧 JSW（p  = 0.004 和p  = 0.011）膝关节内翻对齐的参与者和平均外侧 JSW 外翻对齐的参与者（p = 0.013)。在 WB-CT 上，25% 的股胫骨隔室显示骨对骨并列，与 NWB-CT (10%, P  = 0.008) 和 WB-XR (8%, P  = 0.012) 相比显着更高。

结论

将 WB-CT 与基于 3D 的评估相结合，可以详细量化股胫关节空间和膝关节对线对 JSW 的影响。WB-CT 显示出明显更多的骨对骨附着，这些在 NWB-CT 和 WB-XR 上被低估甚至无法检测到。