Department of Orthopedic Surgery, Duke University Medical Center.
Department of Orthopaedic Surgery, Ortho Carolina, Durham, NC.
J Pediatr Orthop. 2021 Jul 1;41(6):e404-e410. doi: 10.1097/BPO.0000000000001792.
In young athletes, an association exists between an increased posterior tibial slope (PTS) and the risk of primary anterior cruciate ligament (ACL) injury, ACL graft rupture, contralateral ACL injury, and inferior patient reported outcomes after ACL reconstruction. In spite of this, there is no consensus on the optimal measurement method for PTS in pediatric patients. The purpose of this study was to evaluate the reliability of previously described radiographic PTS measurement techniques.
A retrospective review was performed on 130 patients with uninjured knees between the ages of 6 and 18 years. The medial PTS was measured on lateral knee radiographs by four blinded reviewers using three previously described methods: the anterior tibial cortex (ATC), posterior tibial cortex (PTC), and the proximal tibia anatomic axis (PTAA). The radiographs were graded by each reviewer twice, performed 2 weeks apart. The intrarater and inter-rater reliability were assessed using the intraclass correlation coefficient (ICC). Subgroup analyses were then performed stratifying by patient age and sex.
The mean PTS were significantly different based on measurement method: 12.5 degrees [confidence interval (CI): 12.2-12.9 degrees] for ATC, 7.6 degrees (CI: 7.3-7.9 degrees) for PTC, and 9.3 degrees (CI: 9.0-9.6 degrees) for PTAA (P<0.0001). Measures of intrarater reliability was excellent among all reviewers across all 3 methods of measuring the PTS with a mean ICC of 0.87 (range: 0.82 to 0.92) for ATC, 0.83 (range: 0.82 to 0.87) for PTC, and 0.88 (range: 0.79 to 0.92) for PTAA. The inter-rater reliability was good with a mean ICC of 0.69 (range: 0.62 to 0.83) for the ATC, 0.63 (range: 0.52 to 0.83) for the PTC, and 0.62 (range: 0.37 to 0.84) for the PTAA. Using PTAA referencing, the PTS was greater for older patients: 9.9 degrees (CI: 7.7-9.4 degrees) vs 8.5 degrees (CI: 9.2-10.7 degrees) (P=0.0157) and unaffected by sex: 9.5 degrees (CI: 8.8-10.1 degrees) for females and 9.0 degrees (CI: 8.0-10.0) for males (P=0.4199). There were no major differences in intrarater or inter-rater reliability based on age or sex.
While the absolute PTS value varies by measurement technique, all methods demonstrated an intrarater reliability of 0.83 to 0.88 and inter-rater reliability of 0.61 to 0.69. However, this study highlights the need to identify PTS metrics in children with increased inter-rater reliability.
IV, Case series.
在年轻运动员中，胫骨后倾角（PTS）增加与前交叉韧带（ACL）初次损伤、ACL 移植物断裂、对侧 ACL 损伤以及 ACL 重建后患者报告的结果较差有关。尽管如此，对于儿科患者 PTS 的最佳测量方法仍没有共识。本研究的目的是评估先前描述的 PTS 放射测量技术的可靠性。
对 130 名年龄在 6 至 18 岁之间的无受伤膝关节患者进行回顾性研究。4 名盲法评估者使用三种先前描述的方法（胫骨前皮质（ATC）、胫骨后皮质（PTC）和胫骨近端解剖轴（PTAA））在侧位膝关节 X 线片上测量内侧 PTS。每位评估者两次对 X 线片进行分级，间隔 2 周。使用组内相关系数（ICC）评估内部评估者和外部评估者的可靠性。然后根据患者年龄和性别进行分层进行亚组分析。
根据测量方法，PTS 的平均值差异显著：ATC 为 12.5 度（置信区间（CI）：12.2-12.9 度）、PTC 为 7.6 度（CI：7.3-7.9 度）和 PTAA 为 9.3 度（CI：9.0-9.6 度）（P<0.0001）。所有评估者在所有 3 种 PTS 测量方法中均具有极好的内部评估者可靠性，平均 ICC 为 0.87（范围：0.82 至 0.92），用于 ATC、0.83（范围：0.82 至 0.87）用于 PTC 和 0.88（范围：0.79 至 0.92）用于 PTAA。外部评估者的可靠性良好，平均 ICC 为 0.69（范围：0.62 至 0.83）用于 ATC、0.63（范围：0.52 至 0.83）用于 PTC 和 0.62（范围：0.37 至 0.84）用于 PTAA。使用 PTAA 参考，年龄较大的患者 PTS 较大：9.9 度（CI：7.7-9.4 度）与 8.5 度（CI：9.2-10.7 度）（P=0.0157），不受性别影响：女性为 9.5 度（CI：8.8-10.1 度），男性为 9.0 度（CI：8.0-10.0）（P=0.4199）。基于年龄或性别，内部评估者或外部评估者的可靠性没有明显差异。
虽然绝对 PTS 值因测量技术而异，但所有方法的内部评估者可靠性均为 0.83 至 0.88，外部评估者可靠性为 0.61 至 0.69。然而，本研究强调需要确定具有更高的内部评估者可靠性的儿童 PTS 指标。
IV，病例系列。
