Background

Biomechanical effects of anterior knee pain are difficult to distinguish from effects of other factors also related to knee injury (e.g., joint effusion). The purpose of this study was to evaluate independent effects of anterior knee pain on landing and jumping biomechanics.

Methods

Thirteen healthy participants performed a land and jump movement task, under three experimental conditions (pre-pain, pain, and post-pain), during one data collection session. One 1-ml injection of hypertonic saline into the infrapatellar fat pad was used to induce experimental anterior knee pain during the pain condition. Participant-perceived anterior knee pain was measured every 2 min throughout data collection. Landing and jumping biomechanics were measured and compared between the experimental conditions using a functional statistical approach.

Findings

The aforementioned injection increased mean participant-perceived anterior knee pain, from zero during the pre-pain condition to 2.6 ± 0.71 cm during the pain condition. Vertical ground reaction force, knee flexion angle, and internal knee extension moment decreased by approximately 0.100 body weights, 3°, and 0.010 Nm/body weight × body height, respectively, between the pre-pain and pain conditions. Conversely, hip flexion angle and internal hip extension moment increased by approximately 3° and 0.006 Nm/body weight × body height, respectively, between the pre-pain and pain conditions. Several biomechanical changes persisted after anterior knee pain abatement (the post-pain condition).

Interpretation

Anterior knee pain alters landing and jumping biomechanics, independent of other injury-related factors. These altered biomechanics likely change knee joint loading patterns and might increase risk for chronic knee joint injury and/or pathology.

背景

膝关节前部疼痛的生物力学影响很难与其他与膝关节损伤相关的因素（例如，关节积液）的影响区分开来。本研究的目的是评估膝前疼痛对着地和跳跃生物力学的独立影响。

方法

十三名健康参与者在一个数据收集会话期间在三种实验条件（疼痛前、疼痛和疼痛后）下执行了着陆和跳跃运动任务。将 1 毫升高渗盐水注射到髌下脂肪垫中，用于在疼痛条件下诱发实验性膝前部疼痛。在整个数据收集过程中，每 2 分钟测量一次参与者感知的膝前疼痛。使用功能统计方法测量和比较实验条件之间的着陆和跳跃生物力学。

发现

上述注射增加了参与者感知的平均膝前部疼痛，从疼痛前状态下的零到疼痛状态下的 2.6 ± 0.71 cm。在疼痛前和疼痛状态之间，垂直地面反作用力、膝关节屈曲角度和膝关节内伸力矩分别减少了大约 0.100 体重、3°和 0.010 Nm/体重×身高。相反，在疼痛前和疼痛状态之间，髋关节屈曲角度和髋关节内伸力矩分别增加了大约 3° 和 0.006 Nm/体重 × 身高。膝盖前部疼痛减轻（疼痛后状况）后，一些生物力学变化持续存在。

解释

膝前疼痛会改变着地和跳跃的生物力学，与其他与损伤相关的因素无关。这些改变的生物力学可能会改变膝关节负荷模式，并可能增加慢性膝关节损伤和/或病理的风险。