Background 

Approximately one-fourth of TKAs will be performed in patients 55 years or younger within the next decade. Postoperative outcomes for younger patients who had a knee arthroplasty were systematically reviewed in 2011; however, numerous studies evaluating young patients who had both a TKA and unicompartmental knee arthroplasty (UKA) have been reported in the past decade. Therefore, to better counsel this growing population of young patients undergoing knee arthroplasty, an updated understanding of their expected postoperative outcomes is warranted.

Questions/purposes 

In this systematic review, we evaluated (1) all-cause survivorship, (2) reasons for revision, (3) patient-reported outcomes, and (4) return to physical activity and sport in patients 55 years or younger undergoing primary TKA or UKA.

Methods 

A comprehensive search of PubMed, Medline, SportDiscus, and CINAHL was performed to identify all original studies evaluating outcomes after primary knee arthroplasty for young patients (55 years of age or younger) from inception until March 2021. The following keywords were used: knee, arthroplasty, replacement, pain, function, revision, survivorship, sport, physical activity, and return to play. Only original research studies that were related to knee arthroplasty and reported postoperative outcomes with a minimum 1-year follow-up for patients 55 years or younger were included. Unpublished materials, publications not available in English, and studies with a primary diagnosis of rheumatoid arthritis were excluded. The Methodological Index for Non-Randomized Studies (MINORS) score was used to evaluate the study quality of case series and comparative studies, while the Cochrane Risk of Bias tool and the Jadad scale were used for randomized studies. The primary outcomes of interest for this study were all-cause survivorship rate, reasons for all-cause revision, Knee Society and Knee Society Function scores (minimum clinically important difference [MCID] 7.2 and 9.7, respectively), WOMAC scores (MCID 10), Tegner scores (no reported MCID for knee arthroplasty), and return to physical activity or sport. Knee Society and Knee Society Function scores range from 0 to 100, with scores from 85 to 100 considered excellent and below 60 representing poor outcomes. All-cause survivorship rate and reasons for revision were both reported in 17 total studies. Knee Society scores were presented in 19 and Knee Society Function scores were reported in 18 included studies. WOMAC scores and Tegner scores were each found in four included studies, and return to physical activity and return to sport analyses were performed in seven studies. Overall, 21 TKA studies and five UKA studies were included in this analysis, featuring 3095 TKA knees and 482 UKA knees.

Results 

Kaplan-Meier estimates of all-cause survivorship ranged from 90% to 98% at 5 to 10 years of follow-up after TKA and from 84% to 99% (95% CI 93% to 98%) at 10 years to 20 years post-TKA. All-cause UKA survivorship was 90% at 10 years and 75% at 19 years in the largest Kaplan-Meier estimate of survivorship for patients younger than 55 who underwent UKA. Common reasons for revision in TKA patients were polyethylene wear/loosening, aseptic tibial loosening, and infection, and in UKA patients the common reasons for revision were knee pain, aseptic loosening, progression of knee osteoarthritis, and polyethylene wear/loosening. Knee Society scores ranged from 85 to 98 for 5-year to 10-year follow-up and ranged from 86 to 97 at 10-year to 20-year follow-up in TKA patients. Knee Society Function scores ranged from 70 to 95 for 5-year to 10-year follow-up and ranged from 79 to 86 at 10-year to 20-year follow-up. Return to physical activity and sport was reported variably; however, most patients younger than 55 have improved physical activity levels after knee arthroplasty relative to preoperative levels.

Conclusion 

Although all-cause survivorship rates were frequently above 90% and patient-reported outcome scores were generally in the good to excellent range, several studies reported long-term survivorship rates from 70% to 85% and fair patient-reported outcome scores, which must be factored into any preoperative counseling with patients. We could not control for surgeon volume in this report, and prior research suggests that increasing volume is associated with less frequent complications; in addition, the studies we included were variably affected by selection bias, transfer bias, and assessment bias, which makes it likely that the findings of our review represent best-case estimates. To limit the frequency of revision in patients younger than 55 years undergoing TKA, clinicians should be cautious of polyethylene wear/loosening, aseptic tibial loosening, and infection, while knee pain and progression of knee osteoarthritis are also common reasons for revision in patients younger than 55 undergoing UKA. Further research should isolate younger knee arthroplasty patients and evaluate postoperative activity levels while accounting for preoperative physical activity and sport participation.

Level of Evidence 

Level IV, therapeutic study.

中文翻译：

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55 岁以下接受初次膝关节置换术的患者的全因生存率和功能结果如何？系统回顾

背景 

未来十年内，大约四分之一的 TKA 将在 55 岁或更年轻的患者中进行。2011 年对年轻膝关节置换术患者的术后结果进行了系统评价；然而，过去十年中报道了许多评估接受全膝关节置换术和单间室膝关节置换术 (UKA) 的年轻患者的研究。因此，为了更好地为不断增长的接受膝关节置换术的年轻患者提供咨询，有必要对其预期的术后结果有最新的了解。

问题/目的 

在本次系统评价中，我们评估了 55 岁或以下接受初次 TKA 或手术的患者的 (1) 全因生存率，(2) 翻修原因，(3) 患者报告的结果，以及 (4) 恢复体力活动和运动。英国。

方法 

对 PubMed、Medline、SportDiscus 和 CINAHL 进行了全面检索，以确定从开始到 2021 年 3 月对年轻患者（55 岁或以下）初次膝关节置换术后结果进行评估的所有原始研究。使用了以下关键词：膝关节、关节置换术、置换、疼痛、功能、翻修、生存、运动、体力活动和重返比赛。仅纳入与膝关节置换术相关并报告术后结果且对 55 岁或以下患者进行至少 1 年随访的原始研究。未发表的材料、没有英文版的出版物以及初步诊断为类风湿性关节炎的研究被排除在外。非随机研究方法学指数（MINORS）评分用于评估病例系列和比较研究的研究质量，而Cochrane偏倚风险工具和Jadad量表用于随机研究。本研究的主要结果是全因生存率、全因翻修原因、膝关节协会和膝关节协会功能评分（最小临床重要差异 [MCID] 分别为 7.2 和 9.7）、WOMAC 评分 (MCID 10) 、Tegner 评分（未报告膝关节置换术的 MCID），并恢复体力活动或运动。膝关节协会和膝关节协会功能评分范围为 0 至 100，其中 85 至 100 分为优秀，低于 60 表示结果较差。总共 17 项研究报告了全因生存率和修改原因。膝关节协会评分在 19 项纳入研究中提出，膝关节协会功能评分在 18 项纳入研究中报告。WOMAC 评分和 Tegner 评分分别在四项纳入的研究中找到，并在七项研究中进行了恢复体力活动和恢复运动分析。总体而言，本次分析纳入了 21 项 TKA 研究和 5 项 UKA 研究，其中包括 3095 例 TKA 膝关节和 482 例 UKA 膝关节。

结果 

Kaplan-Meier 估计全因生存率在 TKA 术后 5 至 10 年随访时为 90% 至 98%，在 10 年至 20 年随访时为 84% 至 99%（95% CI 93% 至 98%）全膝关节置换术后。根据 Kaplan-Meier 对 55 岁以下接受 UKA 患者生存率的最大估计，10 年全因 UKA 生存率为 90%，19 年生存率为 75%。TKA 患者翻修的常见原因是聚乙烯磨损/松动、无菌性胫骨松动和感染，而 UKA 患者翻修的常见原因是膝关节疼痛、无菌性松动、膝骨关节炎进展和聚乙烯磨损/松动。TKA 患者的 5 至 10 年随访中膝关节协会评分为 85 至 98 分，10 至 20 年随访中评分为 86 至 97 分。5 年至 10 年随访时膝关节协会功能评分范围为 70 至 95，10 年至 20 年随访时评分范围为 79 至 86。恢复体力活动和运动的报告各不相同；然而，大多数 55 岁以下的患者在膝关节置换术后相对于术前水平有所改善。

结论 

尽管全因生存率经常高于 90%，患者报告的结果评分通常在良好到优秀的范围内，但一些研究报告的长期生存率在 70% 至 85% 之间，患者报告的结果评分也相当公平，这必须纳入与患者的任何术前咨询中。在本报告中，我们无法控制外科医生的手术量，之前的研究表明，手术量的增加与并发症的发生率较低有关；此外，我们纳入的研究受到选择偏倚、转移偏倚和评估偏倚的不同影响，这使得我们的审查结果很可能代表最佳情况的估计。为了限制接受 TKA 的 55 岁以下患者的翻修频率，临床医生应警惕聚乙烯磨损/松动、无菌性胫骨松动和感染，而膝关节疼痛和膝骨关节炎的进展也是 55 岁以下患者翻修的常见原因。 55 正在接受 UKA。进一步的研究应该隔离年轻的膝关节置换术患者并评估术后活动水平，同时考虑术前的体力​​活动和运动参与。

证据水平 

IV级，治疗研究。