Center for Cartilage Repair and Sports Medicine, Department of Orthopaedic Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Department of Orthopaedic Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Am J Sports Med. 2023 Jul;51(9):2291-2299. doi: 10.1177/03635465231163856.
Coronal and sagittal malalignment of the knee are well-recognized risk factors for failure after anterior cruciate ligament (ACL) reconstruction (ACLR). However, the effect of axial malalignment on graft survival after ACLR is yet to be determined.
To evaluate whether increased tibiofemoral rotational malalignment, namely, tibiofemoral rotation angle (TFA) and tibial tubercle-trochlear groove (TT-TG) distance, is associated with graft failure after ACLR.
Cohort study; Level of evidence, 3.
In this retrospective matched control study of a single center's database, 151 patients who underwent revision ACLR because of graft failure (ACLR failure group, defined as symptomatic patients with anterior knee instability and an ACL graft tear appreciated on magnetic resonance imaging [MRI] and confirmed during arthroscopic surgery) were compared with a matched control group of 151 patients who underwent primary ACLR with no evidence of failure after ≥2-year follow-up (intact ACLR group). Patients were matched by sex, age, and meniscal injury during primary ACLR. Axial malalignment was assessed on preoperative MRI through the TFA and the TT-TG distance. Sagittal alignment was measured through the posterior tibial slope on MRI. The optimal TFA cutoff associated with graft failure was identified by a receiver operating characteristic curve. The Kaplan-Meier curve with log-rank analysis was performed to evaluate the influence of the TFA on ACLR longevity.
The mean age was 25.7 ± 10.4 years for the ACLR failure group and 25.9 ± 10.0 years for the intact ACLR group. Among all the included patients, 174 (57.6%) were male. In the ACLR failure group, the mean TFA was 5.8°± 4.5° (range, -5° to 16°), while it was 3.0°± 3.3° (range, -3° to 15°) in the intact ACLR group ( < .001). Neither the TT-TG distance nor the posterior tibial slope presented statistical differences between the groups. The receiver operating characteristic curve suggested an optimal TFA cutoff of 4.5° for graft failure (area under the curve = 0.71; < .001; sensitivity, 68.2%; specificity, 75.5%). Considering this a threshold, patients who had a TFA ≥4.5° had 6.6 times higher odds of graft failure compared with patients with a TFA <4.5° ( < .001). Survival analysis demonstrated a 5-year survival rate of 81% in patients with a TFA <4.5°, while it was 44% in those with a TFA ≥4.5° ( < .001).
An increased TFA was associated with increased odds of ACLR failure when the TFA was ≥4.5°. Measuring the TFA in patients with ACL tears undergoing reconstruction may inform the surgeon about additional factors that may require consideration before ACLR for a successful outcome.
膝关节冠状面和矢状面的错位是前交叉韧带（ACL）重建（ACLR）后失败的公认危险因素。然而，ACL 重建后轴向错位对移植物存活率的影响仍有待确定。
评估胫骨股骨旋转对线不良（即胫骨股骨旋转角[TFA]和胫骨结节滑车沟[TT-TG]距离）是否与 ACLR 后移植物失败有关。
单中心数据库的队列研究；证据水平，3 级。
在这项回顾性匹配对照研究中，对因移植物失败（ACLR 失败组，定义为有症状的前膝不稳定患者，在 MRI 上发现 ACL 移植物撕裂，并在关节镜手术中得到证实）而接受再次 ACLR 的 151 例患者与 151 例初次 ACLR 后至少 2 年随访未见失败的匹配对照组（完整 ACLR 组）进行比较。患者按性别、年龄和初次 ACLR 时的半月板损伤进行匹配。通过 TFA 和 TT-TG 距离在术前 MRI 上评估轴向对线不良。通过 MRI 上的后胫骨斜率测量矢状面排列。通过受试者工作特征曲线确定与移植物失败相关的最佳 TFA 临界值。采用 Kaplan-Meier 曲线和对数秩分析评估 TFA 对 ACLR 寿命的影响。
ACLR 失败组的平均年龄为 25.7±10.4 岁，完整 ACLR 组为 25.9±10.0 岁。所有纳入的患者中，174 例（57.6%）为男性。在 ACLR 失败组中，TFA 的平均值为 5.8°±4.5°（范围，-5°至 16°），而在完整 ACLR 组中为 3.0°±3.3°（范围，-3°至 15°）（<0.001）。两组之间 TT-TG 距离或后胫骨斜率均无统计学差异。受试者工作特征曲线提示，TFA 临界值为 4.5°时可用于预测移植物失败（曲线下面积=0.71；<0.001；灵敏度，68.2%；特异性，75.5%）。考虑到这一阈值，TFA≥4.5°的患者移植物失败的可能性是 TFA<4.5°的患者的 6.6 倍（<0.001）。生存分析显示，TFA<4.5°的患者 5 年生存率为 81%，而 TFA≥4.5°的患者为 44%（<0.001）。
当 TFA≥4.5°时，TFA 增加与 ACLR 失败的几率增加有关。在接受 ACL 重建的 ACL 撕裂患者中测量 TFA 可能会告知外科医生在 ACLR 前需要考虑其他可能影响手术效果的因素。
