PURPOSE Rupture of the Achilles tendon (AT) is a common injury. Strength deficits may persist over the long term, possibly owing to elongation of the tendon or inferior mechanical properties. This study aimed to provide a systematic review of the literature on the prevalence and consequences of tendon elongation in patients after acute AT rupture treatment. It was hypothesized that an elongated tendon would be associated with a worse clinical outcome. METHODS The databases for MEDLINE, CENTRAL and Web of Science were searched. Clinical studies related to AT rupture reporting tendon elongation and clinical or functional outcomes, with a minimum follow-up of 6 months, were eligible for inclusion. Only studies testing for statistical correlations (SCs) between AT elongation and other outcomes were eligible, with the exception of biomechanical studies in which statistically significant AT elongation was found to be a generalized finding in the study group. For these studies to be eligible, the study group had to be compared with a healthy control group, or the injured limb compared with the uninjured limb, regarding biomechanical parameters. RESULTS Twenty-eight papers were selected for inclusion. Mean AT elongation measured with imaging techniques ranged from 0.15 to 3.1 cm (n = 17). Ten studies investigated SCs with Patient Reported Outcome Measures (PROMs), in which two found SCs with tendon elongation. Five studies reported strength and power evaluations and their correlation with AT elongation, with two having found SCs between decreased strength and tendon elongation. In ten studies reporting data on biomechanical tests, nine found influence of tendon elongation. In this group, four out of five studies found SCs with biomechanical parameters. CONCLUSION Fair evidence of the influence of tendon elongation in biomechanical parameters was found. In a general population, evidence of a detrimental effect of tendon elongation on PROMs or functional strength at follow-up was not found in this review. LEVEL OF EVIDENCE Level IV.

中文翻译：

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急性破裂后跟腱伸长：有问题吗？系统的审查。

目的跟腱断裂（AT）是常见的损伤。强度缺陷可能会长期持续存在，这可能是由于肌腱伸长或机械性能较差所致。这项研究的目的是对急性AT破裂治疗后患者肌腱伸长的发生率和后果进行文献综述。据推测，肌腱拉长会导致较差的临床预后。方法检索MEDLINE，CENTRAL和Web of Science的数据库。至少随访6个月的与AT断裂报告肌腱伸长和临床或功能预后相关的临床研究符合纳入条件。只有测试AT延长与其他结局之间的统计相关性（SC）的研究才合格，除了生物力学研究外，在统计学上显着的AT延长被认为是研究组的普遍发现。为了使这些研究符合条件，就生物力学参数而言，必须将研究组与健康对照组进行比较，或者将受伤肢体与未受伤肢体进行比较。结果入选了28篇论文。用成像技术测得的平均AT伸长率为0.15至3.1 cm（n = 17）。十项研究使用患者报告的结果指标（PROM）对SC进行了调查，其中两项发现SC的肌腱伸长。五项研究报告了强度和力量评估及其与AT伸长的相关性，其中两项研究发现强度和肌腱伸长之间存在SC。在十项报告生物力学测试数据的研究中，九人发现肌腱伸长的影响。在该组中，五分之四的研究发现SC具有生物力学参数。结论找到了肌腱伸长对生物力学参数影响的合理证据。在一般人群中，未发现肌腱伸长对PROM或随访时功能强度有不利影响的证据。证据级别IV。