Abstract：
BACKGROUND: People with patellofemoral pain (PFP) may have lower performance during the forward step-down and single-leg hop with their painful (unilateral complaints) or most painful (bilateral complaints) limb when compared to pain-free controls. Yet, no study has investigated the appropriateness of using the pain-free/less painful limb as a reference standard in clinical practice or whether deficits might be present depending on the laterality of pain.
OBJECTIVE: To compare performance scores and proportion of side-to-side limb symmetry during the forward step-down and single-leg hop tests among people with unilateral and bilateral PFP, and pain-free controls.
METHODS: Cross-sectional study.
METHODS: Laboratory.
METHODS: Fifty-two young adults (18-35 years old) with unilateral PFP, 72 with bilateral PFP, and 76 controls.
METHODS: Group-by-limb interactions on the performance during the step- down (repetitions) and hop test (distance [cm] normalized by the limb length) were investigated using a repeated-measures analysis of covariance controlling for sex. Pairwise comparisons were interpreted using effect sizes. A Chi-square test was used to compare the proportion of symmetry/asymmetry (cutoff point of ≥ 90% for symmetries indices) across groups and tests.
RESULTS: Main effects for groups (small-to-medium effects) but not limbs indicated lower performance of both limbs of individuals with unilateral and bilateral PFP compared to controls during forward step-downs and single-leg hop tests. No significant differences for the proportion of symmetry/asymmetry were identified across groups (p ≥ 0.05), which further suggests an impaired physical performance of the contralateral limb.
CONCLUSIONS: Our results indicate bilateral deficits in the physical performance of people with unilateral and bilateral PFP when compared to pain-free controls during the forward step-down and single-leg hop tests. Limb symmetries indices greater than 90% should be interpreted with caution, as they may overstate the physical performance by not assuming bilateral deficits.
OBJECTIVE: To compare performance scores and proportion of side-to-side limb symmetry during the forward step-down and single-leg hop tests among people with unilateral and bilateral PFP, and pain-free controls.
METHODS: Cross-sectional study.
METHODS: Laboratory.
METHODS: Fifty-two young adults (18-35 years old) with unilateral PFP, 72 with bilateral PFP, and 76 controls.
METHODS: Group-by-limb interactions on the performance during the step- down (repetitions) and hop test (distance [cm] normalized by the limb length) were investigated using a repeated-measures analysis of covariance controlling for sex. Pairwise comparisons were interpreted using effect sizes. A Chi-square test was used to compare the proportion of symmetry/asymmetry (cutoff point of ≥ 90% for symmetries indices) across groups and tests.
RESULTS: Main effects for groups (small-to-medium effects) but not limbs indicated lower performance of both limbs of individuals with unilateral and bilateral PFP compared to controls during forward step-downs and single-leg hop tests. No significant differences for the proportion of symmetry/asymmetry were identified across groups (p ≥ 0.05), which further suggests an impaired physical performance of the contralateral limb.
CONCLUSIONS: Our results indicate bilateral deficits in the physical performance of people with unilateral and bilateral PFP when compared to pain-free controls during the forward step-down and single-leg hop tests. Limb symmetries indices greater than 90% should be interpreted with caution, as they may overstate the physical performance by not assuming bilateral deficits.
摘要：
背景：与无痛对照组相比，髌股疼痛（PFP）患者在前下步和单腿跳跃过程中的表现可能较低，其肢体疼痛（单侧主诉）或最疼痛（双侧主诉）。然而，没有研究调查在临床实践中使用无痛/疼痛较轻的肢体作为参考标准的适当性,或者根据疼痛的偏侧性是否存在缺陷.
目的：比较单侧和双侧PFP患者在前向下步和单腿跳跃测试中的表现得分和左右肢体对称性的比例，和无痛控制。
方法：横断面研究。
方法：实验室。
方法：52名单侧PFP的年轻人（18-35岁），72与双边PFP，76个控件。
方法：使用重复测量的协方差分析，研究了在步降（重复）和跳跃测试（通过肢体长度归一化的距离[cm]）期间对表现的逐组相互作用性别控制。使用效应大小解释成对比较。使用卡方检验比较各组和测试中对称/不对称的比例（对称指数的截止点≥90％）。
结果：组的主要影响（小到中等影响），而不是四肢，表明与对照组相比，单侧和双侧PFP个体的四肢表现较低。和单腿跳跃测试。各组间对称性/不对称性比例无显著差异(p≥0.05)，这进一步表明对侧肢体的身体表现受损。
结论：我们的结果表明，在正向步降和单腿跳跃测试中，与无痛对照组相比，单侧和双侧PFP患者的身体表现存在双侧缺陷。肢体对称指数大于90%应谨慎解释。因为他们可能通过不假设双边赤字来夸大身体表现。
目的：比较单侧和双侧PFP患者在前向下步和单腿跳跃测试中的表现得分和左右肢体对称性的比例，和无痛控制。
方法：横断面研究。
方法：实验室。
方法：52名单侧PFP的年轻人（18-35岁），72与双边PFP，76个控件。
方法：使用重复测量的协方差分析，研究了在步降（重复）和跳跃测试（通过肢体长度归一化的距离[cm]）期间对表现的逐组相互作用性别控制。使用效应大小解释成对比较。使用卡方检验比较各组和测试中对称/不对称的比例（对称指数的截止点≥90％）。
结果：组的主要影响（小到中等影响），而不是四肢，表明与对照组相比，单侧和双侧PFP个体的四肢表现较低。和单腿跳跃测试。各组间对称性/不对称性比例无显著差异(p≥0.05)，这进一步表明对侧肢体的身体表现受损。
结论：我们的结果表明，在正向步降和单腿跳跃测试中，与无痛对照组相比，单侧和双侧PFP患者的身体表现存在双侧缺陷。肢体对称指数大于90%应谨慎解释。因为他们可能通过不假设双边赤字来夸大身体表现。
