Background:

Osteoarthritis (OA) is a significant long term concern after anterior cruciate ligament (ACL) reconstruction (ACLR). A low bone mineral density (BMD), particularly in the subchondral region, has been associated with the development of OA and is evident at the knee in patients long after ACLR. It is unknown if persistent BMD deficits are present in high level collegiate athletes.

Purpose/Hypothesis:

The purpose of this study was to evaluate bilateral changes in the BMD of the femur and tibia from before the injury to 24 months after ACLR in collegiate athletes. We hypothesized that the BMD of both the distal femur and the proximal tibia would be significantly reduced within the surgical limb initially postoperatively but return to preinjury levels by 24 months after ACLR.

Study Design:

Cohort study; Level of evidence, 2.

Methods:

A total of 33 Division I collegiate athletes were identified between 2010 and 2021 (13 female) who underwent total body dual-energy X-ray absorptiometry (DXA) before sustaining an ACL injury. DXA was repeated at 6, 12, and 24 months after ACLR. Linear mixed effects models assessed differences in the BMD at 5%, 15%, and 50% of the femur's length (F₅, F₁₅, F₅₀) and at 5%, 15%, and 50% of the tibia's length (T₅, T₁₅, T₅₀) within each limb from before the injury to 24 months after ACLR, reported as Tukey-adjusted P values.

Results:

Compared with before the injury, the BMD at F₅ of the surgical limb was reduced by 0.15 g/cm² (SE, 0.02 g/cm²) at 6 months (P < .001). The BMD at F₁₅ of the surgical limb was reduced by 0.06 g/cm² (SE, 0.01 g/cm²), 0.09 g/cm² (SE, 0.01 g/cm²), and 0.09 g/cm² (SE, 0.01 g/cm²) at 6, 12, and 24 months, respectively (all P < .001). The BMD at T₅ of the nonsurgical limb was reduced by 0.07 g/cm² (SE, 0.02 g/cm²) at 12 months (P = .02) and 0.10 g/cm² (SE, 0.02 g/cm²) at 24 months (P = .001). The BMD at T₁₅ of the surgical limb was reduced by 0.07 g/cm² (SE, 0.01 g/cm²) at 6 months and 0.08 g/cm² (SE, 0.02 g/cm²) at 12 months (P < .001).

Conclusion:

BMD deficits at F₁₅ of the surgical limb persisted out to 24 months (–7.1%) after ACLR compared with before the injury in collegiate athletes. The BMD at F₅ and T₁₅ of the surgical limb was reduced at 6 and 12 months but not at 24 months compared with preinjury levels. For the nonsurgical limb, no significant differences were detected, except for the T₅ region at 12 months (–5.1%) and 24 months (–7.2%). The BMD at F₅₀ and T₅₀ of both limbs was not significantly different than preinjury levels at any time after ACLR.

中文翻译：

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大学一级运动员受伤前至前十字韧带重建后2年股骨、胫骨骨密度变化

背景：

骨关节炎 (OA) 是前十字韧带 (ACL) 重建 (ACLR) 后的一个重要的长期问题。骨矿物质密度 (BMD) 低，尤其是软骨下区域，与 OA 的发生有关，并且在 ACLR 术后很长时间的患者中，膝关节的骨矿物质密度 (BMD) 较低。目前尚不清楚高水平大学运动员是否存在持续的骨密度不足。

目的/假设：

本研究的目的是评估大学运动员从受伤前到 ACLR 后 24 个月期间股骨和胫骨双侧 BMD 的变化。我们假设手术肢体内股骨远端和胫骨近端的 BMD 在术后最初都会显着降低，但在 ACLR 后 24 个月恢复到损伤前的水平。

学习规划：

队列研究；证据级别，2。

方法：

2010 年至 2021 年间，共有 33 名 I 级大学运动员（13 名女性）在遭受 ACL 损伤之前接受了全身双能 X 射线吸收测定法 (DXA)。ACLR 后 6、12 和 24 个月重复 DXA。线性混合效应模型评估了股骨长度的 5%、15% 和 50%（F ₅、F ₁₅、F ₅₀）和胫骨长度的 5%、15% 和 50%（T从受伤前到 ACLR 后 24 个月，每个肢体内的图₅、T ₁₅、T _{50 ），报告为 Tukey 调整的}P值。

结果：

_{与受伤前相比，6个月时手术肢体的F 5} BMD降低了0.15 g/cm ² (SE, 0.02 g/cm ² ) ( P < .001)。_{手术肢体F 15}处的BMD减少了0.06 g/cm ² (SE, 0.01 g/cm ² )、0.09 g/cm ² (SE, 0.01 g/cm ² )和0.09 g/cm ² (SE ，0.01 g/cm ²）分别在 6、12 和 24 个月时（所有P < .001）。_{12 个月时，非手术肢体的 T 5} BMD降低了 0.07 g/cm ² (SE, 0.02 g/cm ² ) ( P= .02) 和 24 个月时 0.10 g/cm ² (SE, 0.02 g/cm ² ) ( P = .001)。_{手术肢体 T 15}时的 BMD在 6 个月时降低了 0.07 g/cm ² (SE, 0.01 g/cm ² ) ，在 12 个月时降低了0.08 g/cm ² (SE, 0.02 g/cm ^{2 ) (} P < .001）。

结论：

与大学运动员受伤前相比，ACLR 后手术肢体F ₁₅的BMD 缺陷持续了 24 个月（–7.1%）。与受伤前水平相比，手术肢体的 F ₅和 T ₁₅骨密度在 6 个月和 12 个月时有所降低，但在 24 个月时没有降低。对于非手术肢体，除了 12 个月 (–5.1%) 和 24 个月 (–7.2%) 时的 T ₅区域外，未检测到显着差异。ACLR 后任何时间点，双肢F ₅₀和 T ₅₀的BMD与受伤前水平没有显着差异。