BACKGROUND A hip flexion contracture (HFC) results in an inability to extend the hip by reducing the ROM of the affected hip. The condition affects one in four patients with above-knee amputations on the amputation side. While HFC in other disorders is known to decrease hip ROM and increase pelvic tilt during gait, its impact on the gait of patients with above-knee amputations remains unexplored. Typically, prosthetists design the socket with a flexion angle matching the HFC, potentially leading to compensations during the posterior stance phase of the gait cycle. To our knowledge, little is known about how or whether these compensations relate to the socket's flexion alignment. QUESTIONS/PURPOSES (1) Is the presence of HFC associated with modifications of spatiotemporal and kinematic parameters during gait in patients with an above-knee amputation? (2) Is there a correlation between the socket flexion angle and the spatiotemporal and kinematic parameters during gait in patients with an above-knee amputation with and without HFC? METHODS A comparative observational study was conducted between February 2022 and June 2023. Thirty-two participants with unilateral above-knee amputations who had undergone amputation at least 1 year prior and had a minimum of 1 month of experience with their current prostheses were eligible for consideration and included in the study. After the trial, 1 of 32 participants was excluded due to other impairments affecting gait, and 9% (3 of 32) were excluded because of pain or discomfort during data acquisition on their gait, leaving 88% (28 of 32) of participants included in the analysis. The median (IQR) age of participants in the HFC group (n = 13) was 50 years (26 to 56); 85% (11) were male and 15% (2) were female. The median (IQR) age of participants in the noHFC group (n = 15) was 41 years (32 to 56), and 100% were male. Time since amputation was similar between groups (HFC median 8 years [IQR 3 to 21], noHFC median 6 years [IQR 1 to 9], difference of medians 2; p = 0.31). Thirty-two percent (9 of 28) of patients were classified according to the Medicare Functional Classification Level system as K4 (exceeding basic ambulation skills) and 68% (19 of 28) were classified as K3 (ability to walk with variable cadence and traverse most environmental barriers). Clinical and prosthetic measurements were made, which comprised measurement of the HFC using a hand-held goniometer with the patient in the modified Thomas test position, the socket flexion alignment, and the difference (δ) between the HFC and socket flexion alignment. A gait analysis was performed with an optoelectronic system equipped with six infrared cameras and two force plates to analyze the time-distance and kinematic parameters of gait. To answer our first question, we quantitively compared the gait spatiotemporal and kinematic parameters between groups, and for the second question, we evaluated the correlations between the same parameters and prosthesis alignment for both groups. RESULTS During gait, the HFC group exhibited reduced mean ± SD residual hip ROM in comparison with the noHFC group (35° ± 6° versus 44° ± 6°, mean difference -9° [95% CI -13° to -6°]; p < 0.001), increased pelvic tilt (11° ± 6° versus 7° ± 3°, mean difference 4° [95% CI 1° to 8°]; p = 0.02), increased pelvic rotation (12° ± 3° versus 9° ± 2°, mean difference 3° [95% CI 2° to 6°]; p < 0.001), and increased trunk rotation (15° ± 5° and 12° ± 2°, mean difference 3° [95% CI 0° to 6°]; p = 0.04). Greater δ correlated with decreased ROM in the contralateral hip (r = -0.71; p = 0.006), pelvis (r = -0.77; p = 0.002), and trunk (r = -0.58; p = 0.04) in the sagittal plane and with increased residual hip ROM (r = 0.62; p = 0.02). In terms of spatiotemporal gait parameters, in the HFC group, the δ correlated with an increase in contralateral step width (r = 0.58; p = 0.04) and a decrease in prosthetic step length (r = -0.65; p = 0.02). CONCLUSION Our findings further suggest that physiotherapists should consider the pelvic and trunk compensations associated with HFC in their rehabilitation because of potential long-term effects, such as low back pain or osteoarthritis. In addition, the correlation between the socket flexion angle and the parameters involved may support prosthetists in their choices of prosthetic settings. For now, we cannot consider these compensations as an impaired gait syndrome, and future studies are needed to evaluate their impact on patients' quality of life. LEVEL OF EVIDENCE Level III, therapeutic study.

中文翻译：

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臋窝屈曲对线是否与膝上截肢和髋关节屈曲挛缩个体的步态参数变化有关？


背景 髋关节屈曲挛缩 （HFC） 导致无法通过减少受影响髋关节的 ROM 来伸展髋关节。这种情况影响了四分之一的膝盖以上截肢患者。虽然已知其他疾病中的 HFC 会减少步态期间的髋关节活动度并增加骨盆倾斜，但其对膝上截肢患者步态的影响仍未得到探索。通常，修复师设计的接受腔的屈曲角度与 HFC 相匹配，这可能会导致在步态周期的后站位阶段进行补偿。据我们所知，关于这些补偿如何或是否与窝的屈曲对齐有关知之甚少。问题/目的 （1） HFC 的存在是否与膝上截肢患者步态过程中时空和运动学参数的改变有关？（2） 膝上截肢患者伴和不伴 HFC 患者步态时的窝屈曲角与时空和运动学参数之间是否存在相关性？方法 2022 年 2 月至 2023 年 6 月期间进行了一项比较观察研究。32 名单侧膝上截肢参与者至少在 1 年前接受过截肢手术，并且至少有 1 个月使用当前假肢的经验，他们有资格被考虑并纳入研究。试验后，32 名参与者中有 1 名因影响步态的其他障碍而被排除在外，9% （32 名中的 3 名） 因步态数据采集过程中的疼痛或不适而被排除在外，剩下 88% （32 名中的 28 名） 被纳入分析。HFC 组 （n = 13） 参与者的中位 （IQR） 年龄为 50 岁 （26 至 56 岁）;85% （11） 为男性，15% （2） 为女性。 noHFC 组 （n = 15） 参与者的中位 （IQR） 年龄为 41 岁 （32 至 56），其中 100% 为男性。两组截肢后的时间相似 （HFC 中位 8 年 [IQR 3 至 21]，无 HFC 中位 6 年 [IQR 1 至 9]，中位数差异 2;p = 0.31）。根据 Medicare 功能分类级别系统，32%（28 人中的 9 人）被归类为 K4（超过基本的行走技能），68%（28 人中的 19 人）被归类为 K3（能够以可变节奏行走并穿越大多数环境障碍）。进行了临床和修复测量，包括使用手持式测角仪测量 HFC，患者处于改良的 Thomas 测试位置、牙槽屈曲对位以及 HFC 和牙槽屈曲对位之间的差异 （δ）。使用配备 6 个红外摄像头和 2 个测力台的光电系统进行步态分析，以分析步态的时间 - 距离和运动学参数。为了回答我们的第一个问题，我们定量比较了组间的步态时空和运动学参数，对于第二个问题，我们评估了两组相同参数与假体对齐之间的相关性。结果在步态期间，与 noHFC 组相比，HFC 组的平均 ±SD 残余髋关节活动度降低 （35° ± 6° vs 44° ± 6°，平均差 -9° [95% CI -13° 至 -6°];p < 0.001），骨盆倾斜增加 （11° ± 6° vs 7° ± 3°，平均差 4° [95% CI 1° 至 8°];p = 0.02），骨盆旋转增加 （12° ± 3° vs 9° ± 2°， 平均差 3° [95% CI 2° 至 6°];p < 0.001），躯干旋转增加 （15° ± 5° 和 12° ± 2°，平均差 3° [95% CI 0° 至 6°];p = 0.04）。 较大的 δ 与矢状面对侧髋关节 （r = -0.71;p = 0.006）、骨盆 （r = -0.77;p = 0.002） 和躯干 （r = -0.58;p = 0.04） 的 ROM 降低相关，并且残余髋关节活动度增加 （r = 0.62;p = 0.02）。在时空步态参数方面，在 HFC 组中，δ与对侧步宽的增加 （r = 0.58;p = 0.04） 和修复步长的减少 （r = -0.65;p = 0.02） 相关。结论 我们的研究结果进一步表明，物理治疗师在康复中应考虑与 HFC 相关的骨盆和躯干补偿，因为潜在的长期影响，例如腰痛或骨关节炎。此外，接受腔屈曲角度与相关参数之间的相关性可能支持修复专家选择修复设置。目前，我们不能将这些补偿视为步态障碍综合征，需要未来的研究来评估它们对患者生活质量的影响。证据级别 III 级，治疗研究。