冻结肩资料

您的感受

冻结肩通常表现为一种深层的钝痛，这种疼痛在数周内逐渐加重，而非突然发作。对大多数人而言，起初最严重的部分是疼痛，且夜间疼痛往往最为剧烈。侧卧于患侧变得不可能，睡眠中断是整个病程中最令人疲惫的部分之一。

随后，肩部开始僵硬。当您伸手去系安全带、够高处的架子或把手伸进口袋时，手臂会突然无法活动。冻结肩与大多数肩部问题的不同之处在于，这种僵硬并非仅仅是因为您因疼痛而保护性限制活动——即使由他人抬起您的手臂，肩部也确实无法活动。最典型的体征是丧失外旋前臂的能力，就像开门或将手臂伸入衣袖的动作一样。

大多数患者年龄在40至60岁之间。有些人记得发病前曾受过轻微撞击；许多人则完全没有诱因。如果您患有糖尿病或甲状腺疾病，发病率会更高；如果一侧肩部曾发病，另一侧随后发病的可能性也略有增加。

实际情况

您的肩关节位于一层称为关节囊的坚韧组织袖套内。通常，这层袖套是松弛且有弹性的，这使得肩关节能够比体内任何其他关节活动范围更大。在冻结肩（冻结肩）中，关节囊发生炎症，随后增厚并收缩，导致袖套缩小。关节内部的空间最终可能缩小到正常大小的一半以下。

尽管旧称“粘连性关节囊炎”，但关节内部实际上并没有任何组织粘连在一起。不存在类似胶水的粘连。组织变得紧绷，这是一个真正不同的问题，这也是为什么一些外科医生认为该病症应简单地称为肩关节挛缩——即紧绷——的原因。

其发病原因仍未被充分理解，诚实地说，确实如此。有充分证据表明，它不仅仅是肩关节的局部问题。遗传风险研究表明，1型糖尿病确实会导致冻结肩，而不仅仅是与其相关，且这种联系是通过血糖而非体重或机械负荷实现的。组织变化看起来与手部疾病杜普伊特伦挛缩（Dupuytren's disease）惊人地相似，这就是为什么两者经常出现在同一个人身上的原因。

诚实地谈谈需要多长时间

您很可能会读到，冻结肩（冻结肩）是一种自限性疾病，通常在 18 个月至 2 年内完全缓解。我们要对您直言不讳：这种安慰性的说法比现有证据所支持的要更为自信。

认为该疾病会整齐地经历三个阶段——冻结期、冻结期、解冻期——的观点，源自 1975 年发表的一项小型研究，该研究中患者的手臂被悬吊固定长达九个月。毫不奇怪，以这种方式治疗的肩膀会变僵硬，一旦允许活动，又会再次变得松弛。当研究人员回顾所有现有研究时，他们发现没有确凿证据表明未经治疗的肩膀会可靠地经历这些阶段并最终恢复正常。事实上，从未有任何研究证明，未经治疗的人能够恢复到测量上真正正常的活动范围。

证据所显示的更有用，具体如下：您获得的大部分改善往往发生在早期，随后进展放缓并趋于平稳。 这种平台期可能是永久性的。根据您阅读的研究不同，几年后仍有三分之一到一半的人仍有某种程度的酸痛或僵硬，尽管对大多数人来说，这些症状很轻微，不会妨碍他们做自己想做的事。

这并不意味着您不会好转。大多数人的症状会有很大改善。但这意味着，“只是等待，它会自行解决”并不是中立的建议，而且积极治疗疼痛而非单纯忍受疼痛是有充分理由的。

我们能做什么

在洛克汉普顿 Mater 私人医院，Kieran Hirpara 医生会根据让您更困扰的因素——是疼痛还是僵硬——来与您探讨治疗方案，而不是试图将您归入某个固定的分期。

关节内类固醇注射是疼痛期最有证据支持的治疗手段。在大量研究中，它是唯一能可靠地产生患者可感知的疼痛和功能改善差异的治疗，且通常在最初几周内起效。其客观的局限性在于，这种优势在四到六个月左右会逐渐消退。它能为您提供舒适、改善睡眠并恢复肩部工作能力，但并不能治愈僵硬。

锻炼和物理治疗值得进行，但需保持现实的期望。简单的家庭锻炼计划具有可测量的价值。可能会让您感到意外的是，锻炼的强度似乎并不重要：比较强力终末端拉伸与轻柔无痛运动的研究所显示，在六个月和十二个月时的结果并无差异；令人欣慰的是，也没有证据表明加大强度会造成损伤。因此，请在您能承受的范围内进行锻炼。研究表明，忍痛强行锻炼并不能加速康复。

液压扩张术是通过注入液体从内部拉伸关节囊，该方法使用广泛且风险较低。关于其疗效的研究结果确实不一：一项大型综述发现它虽能轻微缓解疼痛，但对活动度改善有限；另一项研究则发现结果相反。这是一个合理的选择，但我们不会过度夸大其效果。

麻醉下手法松解是指在您睡眠状态下，将肩部活动至全范围，以拉伸紧张的关节囊。在比较主要治疗方案的最大型试验中，这是整体性价比最高的选项。

关节镜下关节囊切开术是指在直视下手术切断紧张的关节囊，而不是将其拉伸至撕裂。其主要优势在于疗效更为持久：在已发表的手术系列研究中，松解术后复发僵硬的情况并不常见，而在手法松解后，有相当一部分患者肩部会再次变紧，需要二次手术。在大型英国试验中，接受切开术的患者是三个组别中最不需要进一步治疗的人群。由于这是一种手术，其风险略高于其他替代方案且费用更高，您应预期在最初几周内会比接受手法松解的患者感到更明显的酸痛——但这种早期的差异在六个月左右会趋于一致。

值得了解的是：在该试验中，一年后这三种方法的疗效差异仅在几分之内。这确实是好消息，因为这意味着决策可以基于哪种方案更适合您、您的其他健康状况以及您的具体情况，而不是基于某一种方案明显优于其他方案。

Hirpara 医生通常的治疗顺序。 您不会被要求为了等待某种治疗而忍受固定月数的痛苦。在实践中，他通常会建议首先进行类固醇注射，因为对许多人来说，这足以减轻疼痛，使他们在肩部恢复期间能够继续日常生活。如果注射未能提供充分的缓解，他很乐意从那时起提供关节囊切开术——他并不要求您先挣扎忍受九到十二个月。鉴于“它总会自行痊愈”这一安慰性说法的证据并不稳固，花一年时间忍受疼痛以观察您的病情会如何发展是没有意义的。

预期情况

如果您接受了注射治疗，预计疼痛会在第一至第二周内缓解。请利用这段时间保持肩关节活动。

如果您接受了手法松解或关节囊切开术，您所能恢复的大部分活动度会迅速回归——通常在前四至六周内——并且在大约三个月后一般不会有进一步的显著变化。早期活动至关重要，物理治疗通常在术后一至两天内开始。大多数人可在术后一至三周内恢复办公室类工作。

如果您患有糖尿病，可以预期恢复速度较慢且恢复程度略低于平均水平；另外需了解，类固醇注射可能会在数天内影响您的血糖水平。如果您的血糖控制困难，请告知我们，因为这会改变我们的建议。

无论采取何种治疗途径，恢复期均以月计算，而非周。您能做的最有用的事情是在舒适范围内继续使用患肢，并保证充足的睡眠。

何时就医

如果肩部疼痛在夜间将你痛醒，或在休息数周后仍未缓解，请就诊全科医生；若肩部活动变得真正困难，而非仅仅酸痛，请特别咨询是否患有冻结肩（粘连性肩关节囊炎）。

若出现以下情况，请尽早寻求专科医生评估：无法将手向外旋转、患有糖尿病、肩部疼痛影响工作或驾驶，或疼痛严重到影响睡眠。在评估疼痛之前长时间等待并无益处。

若肩部出现发热、发红和肿胀，或伴有全身不适或发热，或手臂出现明显无力或麻木，或疼痛由跌倒或外伤引起，请立即就医。这些症状提示并非冻结肩，而是需要更紧急处理的其它问题。

更深入的了解

本节内容比您做出自身治疗决策所需的信息更为深入。之所以提供此部分，是因为“冻结肩”（粘连性肩关节囊炎）是一种患者所获告知与科研实际结果之间出现偏差的疾病，部分人更希望了解推理过程，而非仅凭信任接受结论。

关节究竟出了什么问题

关节囊是包裹在关节周围的一层胶原组织袖套。在冻结肩（冻结肩）中，关节囊发生炎症，随后变得纤维化——称为成纤维细胞的细胞增殖并沉积致密的新型胶原，其中部分细胞转化为肌成纤维细胞，后者具有主动收缩能力。这正是其与普通瘢痕的关键区别：组织不仅增厚，还会产生牵拉收紧的作用。关节腔容量可从正常的 10–15 mL 降至 3–4 mL。

手部杜普伊特伦挛缩（Dupuytren's disease）中同样存在相同的细胞行为，这解释了为何这两种疾病常同时出现在同一患者身上，也解释了为何有肩关节外科医生主张将该病直接更名为肩部的挛缩，而非“囊炎”[1]。尽管旧称“粘连性囊炎”，但外科医生在关节镜下观察关节内部时，实际上并未发现任何粘连。

为什么“三阶段”说法的基础比听起来更不稳固

你会在各地读到，冻结肩会经历冻结期、冻结期和解冻期。该模型于1975年提出。当研究人员回溯其来源时，发现作者混淆了两篇较早文献的参考文献，而且——更重要的是——他的患者手臂被悬吊固定长达九个月。肩部如此长时间固定会导致僵硬，而一旦允许活动，僵硬便会缓解。“阶段”可能部分描述的是治疗过程，而非疾病本身。

一项旨在验证该模型的系统评价未能找到支持证据，并发现了与其预测相反的结果：大多数改善发生在早期，随后逐渐减缓，而非在晚期出现解冻 [2]。此外，临床医生也无法可靠地确定某一冻结肩处于哪个阶段——撰写该标准定义的人曾在公开文献中承认，证实该定义的数据“尚不可用”。

恢复统计数据及其两个截然不同答案的原因

常被引用的数据是，94% 的患者无需治疗即可恢复。这一数据源自一项真实研究，但仅统计了那些未接受治疗且返回进行随访的患者。原始群体中的大多数人要么选择了治疗，要么中途退出。若统计所有人群，同一数据得出的恢复率约为 26% [3]。“恢复”的定义还包括患肩活动度与健侧相差在 10 度以内——而在部分此类患者中，健侧肩关节也处于冻结状态。

最长期的随访研究发现，平均四年后仍有 41% 的患者存在症状，且——值得了解的是——症状改善通常在约三年后停止，而非无限期持续 [4]。

这是一种全身性疾病，而非仅限于肩部的疾病

一项大型遗传学研究发现了五个与冻结肩相关的DNA区域，并使用了一种能够区分因果关系与巧合的技术，证实了1型糖尿病确实会导致冻结肩，而不仅仅是伴随发生。超重并未导致冻结肩——在控制糖尿病因素后，超重的关联性消失了。这表明驱动因素是血糖水平，而非机械负荷[5]。

物理治疗证据实际说了什么

如果您正在接受或提供物理治疗，这部分内容最值得关注。一项Cochrane综述汇总了32项试验和1,836名受试者 [6]。其中有三点发现尤为突出。

与类固醇注射相比，手法物理治疗在早期效果较差。 在一项头对头试验中，与单次注射相比，六周的被动活动和监督运动在七周时产生的疼痛改善幅度少26分，功能改善幅度少25分。根据患者是否感觉明显改善或康复的评估，物理治疗组的这一比例为46%，而注射组为77%——这意味着每注射四人，仅比物理治疗多帮助一人。到六至十二个月时，这种差距缩小，差异不再具有临床意义。

施力程度、频率以及使用的技术似乎并不重要。 一项包含100名患者的试验比较了坚定的终末端活动与温和的无痛活动，发现在六或十二个月时，在17项结局指标（包括疼痛、夜间疼痛、功能、各个运动平面、生活质量）上均无显著差异。另一项包含120名患者的试验改变了终末端活动的频率（每周超过两次、每周一次、每周少于一次），发现外展角的差异小于8度，且所有差异在统计学上与零无显著区别。技术之间的头对头比较——前向与后向滑动、本体感觉神经肌肉促进法（PNF）与常规运动、哑铃与徒手——几乎均无显著差异。令人欣慰的是，也没有迹象表明在终末端工作会造成伤害。

最大的结构性空白：从未有任何试验将手法治疗加运动与完全不治疗进行比较。 因此，虽然我们可以说物理治疗并不明显优于注射，且其交付细节似乎不会带来太大变化，但没有人真正证明这种改善中有多少是自然发生的。

两个有用的注意事项。综述中唯一真正高质量的试验考察了关节扩张后的物理治疗，发现其对疼痛、功能或生活质量没有影响——但它提高了自我评定为康复的患者比例，并在六周时增加了约13度的外展角，该增加量在六个月时消失。而在英国的大型试验中，物理治疗组被描述为包括进入僵硬范围的手法拉伸，但其自身记录显示，仅11–27%的患者接受了手法活动，仅有一名患者接受了监督拉伸。实际交付的内容——并在一年时达到与手术相当的效果——是教育、注射、温和的监督运动和家庭锻炼计划。

恢复良好需要多长时间，释放方式的选择是否重要

时间进程。 术后，中位患者在约 1个月 时达到“这确实是真正的改善”的阈值，在约 4个月 时达到“我的肩膀我可以接受”的阈值 [14]。停工时间的中位数为 8周，但分布范围很广——四分之一的患者在4周内复工，四分之三的患者在13周内复工 [15]。

手法松动能更快地恢复活动度。 这是对上述持久性优势的真实权衡：手法松动能更早地恢复关节活动度，而手术松解直到约6个月时才真正赶上，此后在各项汇总指标上两者无显著差异。一项小型比较甚至发现，单纯手法松解的外旋功能最佳 [16]。

需要切断多少关节囊是一个真正的问题，答案是“比你想象的要少”。 一项汇总了 18项研究、629名患者和811个肩关节 的综述比较了三种技术：仅切断关节囊的前侧和下侧、在此基础上增加后侧切断，或进行全周切断。其结论是：范围较小的松解术能带来更好的功能评分和疼痛评分，增加后侧松解虽能带来早期的内旋改善（尽管这种改善不持久，但能带来持久的屈曲改善），而全周 360度松解“可能不会提供任何进一步的益处”。三种方法的并发症发生率无差异 [17]。两项关于后侧延伸松解的随机对照试验发现了相同的模式——早期恢复更快，但在6个月时无差异。因此，更大的手术并不自动意味着更好的效果。

同时联合进行两种操作并非最佳方案。 在唯一的三项对比中，在松解术基础上联合手法松解导致外旋丧失率最高 —— 18%，而单纯手法松解为7%，单纯松解术为2% [16]。

最大的治疗试验实际发现了什么

一项英国试验将略多于500名患者随机分配至接受结构化物理治疗联合注射、麻醉下手法松解或关节镜手术。在一年时，三组结果彼此相差无几——差异小于患者所能察觉的程度 [7]。这确实是有益的消息：这意味着选择可以基于您个人及具体情况来决定，而非某一选项明显优于其他选项。

这三者的区别在于后续需要其他治疗的发生频率。在该试验中，接受松解术后需要进一步治疗的比例为4%，手法松解术后为7%，物理治疗术后为15% [7]。就每单位效益的成本而言，手法松解效果最佳；松解术成本最高，且导致了试验中大多数严重并发症，尽管从绝对值来看这些并发症极为罕见。

手法松解或切开松解——关于复发的问题

正是在这一点上，两种手术真正分道扬镳，这也是尽管总体结局评分看似相同，外科医生仍可能建议您选择切开松解的原因。

手法松解将关节囊拉伸直至撕裂，而撕裂的位置并非总是如您所愿。在最大规模的研究系列中——792 例肩关节随访 17 年——17.8% 的患者需要二次手法松解，而在 1 型糖尿病患者中，这一比例上升至 37.9% [9]。最长随访期平均为 13 年，发现 19.2% 的患者需要重复手法松解，31.3% 的患者在某个时间点描述了复发 [10]。有两点因素使这一情况显得不那么严重：几乎所有复发都发生在第一年（五年后复发率低于 2%），且重复手法松解的效果与首次手法松解大致相当 [9][10]。

切开松解是在直视下有意地切断关节囊。再次手术的发生率显著降低：一项平均随访五年的系列研究显示，32 例患者中无一例需要再次手术，仅有一例因未完成康复而出现复发 [11]。一项汇总了八项研究、共 768 名患者的荟萃分析发现，两种手术在疼痛、功能或活动度方面无显著差异，但指出手法松解组需要更多的额外注射治疗，并得出结论，在更长的随访期内，“手法松解组可能会经历更多复发” [8]。

两个诚实的说明。首先，关于手法松解与复发的大型研究主要来源于一位外科医生的临床实践，因此它们并非相互独立的确认。其次，切开松解也并非完全恢复：一项以患者自身对侧肩关节为对照的研究发现，两到六年后，患者的功能水平约为健侧的 77–79% [12]；在排除糖尿病患者的队列中，虽然几乎所有患者都有显著改善，但仍有 11–22% 的患者在六个月时认为其肩关节状态不可接受 [13]。

因此，诚实的总结是：为了让肩关节恢复活动和舒适，两者大致等效，且手法松解是成本更低的选择。为了维持这种状态，证据支持切开松解。如果您患有糖尿病、肩关节非常僵硬，或者已经接受过未能维持效果的手法松解，那么这种差异就显得尤为重要。

参考文献

[1] Bunker T. 肩周炎需要新名称——肩关节挛缩。Shoulder Elbow. 2009;1(1):4-9. https://doi.org/10.1111/j.1758-5740.2009.00007.x [2] Wong CK, Levine WN, Deo K, Kesting RS, Mercer EA, Schram GA, 等. 冻结肩的自然病程：事实还是虚构？系统综述。Physiotherapy. 2017;103(1):40-7. https://doi.org/10.1016/j.physio.2016.05.009 [3] Vastamäki H, Kettunen J, Vastamäki M. 特发性冻结肩的自然病程：一项2至27年的随访研究。Clin Orthop Relat Res. 2012;470(4):1133-43. https://doi.org/10.1007/s11999-011-2176-4 [4] Hand C, Clipsham K, Rees JL, Carr AJ. 冻结肩的长期预后。J Shoulder Elbow Surg. 2008;17(2):231-6. https://doi.org/10.1016/j.jse.2007.05.009 [5] Green HD, Jones A, Evans JP, Wood AR, Beaumont RN, Tyrrell J, 等. 全基因组关联研究鉴定出5个与冻结肩相关的位点，并提示糖尿病为因果危险因素。PLoS Genet. 2021;17(6):e1009577. https://doi.org/10.1371/journal.pgen.1009577 [6] Page MJ, Green S, Kramer S, Johnston RV, McBain B, Chau M, 等. 手法治疗与运动疗法治疗粘连性关节囊炎（冻结肩）。Cochrane Database Syst Rev. 2014;2014(8):CD011275. https://doi.org/10.1002/14651858.CD011275 [7] Brealey S, Northgraves M, Kottam L, Keding A, Corbacho B, Goodchild L, 等. 初级护理中成人原发性冻结肩的手术治疗与早期结构化物理治疗对比：英国FROST三项随机对照试验。Health Technol Assess. 2020;24(71):1-162. https://doi.org/10.3310/hta24710 [8] Zhao Y, Yang T, Feng C, Li L, Pang L, Zhao S. 关节镜下关节囊松解术与麻醉下手法松解术治疗难治性冻结肩：系统综述与荟萃分析。Orthop Surg. 2024;16(7):1517-29. https://doi.org/10.1111/os.14077 [9] Woods DA, Loganathan K. 麻醉下手法松解术（MUA）后冻结肩的复发。Bone Joint J. 2017;99-B(6):812-7. https://doi.org/10.1302/0301-620X.99B6.BJJ-2016-1133.R1 [10] Fairclough A, Waters C, Davies T, Ali A, Woods D. 麻醉下手法松解术后冻结肩的长期复发。Shoulder Elbow. 2023;15(2):173-80. https://doi.org/10.1177/17585732211070007 [11] Ranalletta M, Rossi LA, Zaidenberg EE, Bertona A, Tanoira I, Maignon GD, 等. 关节镜下前下关节囊松解术治疗特发性粘连性关节囊炎的中期结果。Arthroscopy. 2017;33(3):503-8. https://doi.org/10.1016/j.arthro.2016.08.024 [12] Mardani-Kivi M, Hashemi-Motlagh K, Darabipour Z. 关节镜下冻结肩关节囊松解术：中期结果。Clin Shoulder Elb. 2021;24(3):172-7. https://doi.org/10.5397/cise.2021.00311 [13] Pasqualini I, Tanoira I, Hurley ET, Ranalletta M, Rossi LA. 关节镜下关节囊松解术为粘连性关节囊炎患者带来具有临床意义的疗效。Arthroscopy. 2024;40(4):1081-8. https://doi.org/10.1016/j.arthro.2023.08.083 [14] Pasqualini I, Rossi LA, Oyem PC, Tanoira I, Ranalletta M. 关节镜下关节囊松解术后达到具有临床意义疗效所需的时间。Orthop J Sports Med. 2024;12(11):23259671241275653. https://doi.org/10.1177/23259671241275653 [15] Sedlinsch A, Berndt T, Rühmann O, Lerch S. 冻结肩关节镜下关节囊松解术后的恢复期。J Orthop. 2020;20:374-9. https://doi.org/10.1016/j.jor.2020.06.013 [16] Schoch B, Huttman D, Syed UA, 等. 粘连性关节囊炎的外科治疗：手法松解、关节囊松解及两者联合治疗的比较。Cureus. 2020;12(7):e9032. https://doi.org/10.7759/cureus.9032 [17] Sivasubramanian H, Chua CXK, Lim SY, Manohara R, Ng ZWD, Prem Kumar V, 等. 关节镜下关节囊松解术治疗特发性冻结肩：需要多少松解？Orthop Traumatol Surg Res. 2021;107(1):102766. https://doi.org/10.1016/j.otsr.2020.102766

Evidence & references

This is the clinical evidence summary written for health professionals. It is technical, and it lists the research this page was built from. You do not need to read it to understand your treatment or to make a decision about it.

Overview

Frozen shoulder management guidelines provide evidence-based guidance and identify key areas for future research [2].
Magnetic resonance imaging findings in frozen shoulder should not replace clinical judgments regarding prognosis and treatment decisions [7].
Clinicians should monitor frozen shoulder patients with diabetes more closely and offer further treatment if pain or lack of function persist long-term [8].
Different treatment strategies for frozen shoulder may be appropriate depending on the location [9].
A strict definition of recalcitrant idiopathic frozen shoulder is needed to prevent unnecessary interventions, as current data should not be interpreted as a plea for surgery in patients with a mean symptom duration of 4 months [10].
The variety of participants, methods, interventions, and outcomes across trials provides limited new evidence to inform the non-surgical management and treatment of frozen shoulder [14].
Patients with a poor outcome or recurrent symptoms after manipulation under anaesthetic (MUA) should be offered a further MUA, with an expectation of a good outcome and a low complication rate [17].
Early surgical intervention might shorten the overall duration of symptoms in frozen shoulder and is not associated with inferior clinical outcomes compared with late surgical intervention [19].
There is insufficient evidence to reliably recommend a single treatment approach for frozen shoulder [32].
Further treatment was indicated in 41% of patients who could not tolerate more than 20 mL of injection during hydrodilatation [34].
Recurrence of frozen shoulder was more common in primary (33%) versus secondary (16%) cases [34].
Arthroscopic capsular release is a suitable option for refractory primary frozen shoulder syndrome, leading to faster and long-lasting recovery [35].
Manipulation under anaesthetic (MUA) and arthroscopic capsular release (ACR) are both good treatment options for primary frozen shoulder [70].
MUA is simpler but carries risks of serious complications, whereas ACR may be safer if performed by experienced surgeons and is convenient for patients with combined rotator cuff tears [70].

Anatomy & Pathophysiology

Primary (idiopathic) frozen shoulder consists of three phases: pain, stiffness, and thawing [3].
Secondary frozen shoulders may not exhibit all three phases and may not follow the exact chronology of primary frozen shoulder [3].
The pain phase of primary frozen shoulder involves a gradual onset of diffuse shoulder pain that is progressive over weeks to months [3].
Pain in the initial phase is usually worse at night and exacerbated by lying on the affected side [3].
Reduced arm use due to pain leads to stiffness [3].
The stiffness phase begins when patients restrict movement to seek pain relief and usually lasts 4 to 12 months [3].
During the stiffness phase, patients experience difficulty with activities of daily living, such as men accessing back pockets or women fastening brassieres [3].
A dull ache is present nearly all time during the stiffness phase, especially at night, often accompanied by sharp pain during range of motion at or near new endpoints [3].
The thawing phase lasts for weeks or months, during which motion increases and pain diminishes [3].
Without treatment, motion return in the thawing phase is gradual and may never objectively return to normal, although most patients subjectively feel near normal [3].
Frozen shoulder is characterized by progressive pain and stiffness that usually resolves spontaneously after about 18 months [4].
Histological features of frozen shoulder are reminiscent of Dupuytren’s disease, with active fibroblastic and myofibroblastic proliferation in the rotator interval, anterior capsule, and coracohumeral ligament [4].
Conditions particularly associated with frozen shoulder include diabetes, Dupuytren’s disease, hyperlipidaemia, hyperthyroidism, cardiac disease, and hemiplegia [4].
The etiology of frozen shoulder is still not known and understanding of the pathogenesis is limited [15].
Frozen shoulder is a poorly understood condition that typically involves substantial pain, movement restriction, and considerable morbidity [12].
The pathophysiology of frozen shoulder is complex, involving various pathophysiologic mechanisms [62].
A systematic review summarizes the tissue pathophysiology of primary frozen shoulder [25].
Primary frozen shoulder is defined by total elevation restricted to 135° or less [20].
In primary frozen shoulder, motion restriction is localized to the humero-scapular joint [20].
Primary frozen shoulder excludes cases with post-traumatic conditions, rheumatoid arthritis, osteoarthritis, hemiplegia, or other obvious changes explaining the range of motion decrease [20].
Secondary frozen shoulder involves decreased range of motion following a traumatic lesion, including soft tissue injury, intra- and juxtaarticular fractures, and other upper limb fractures [20].
Symptomatic subjects with frozen shoulder demonstrate substantial kinematic deficits during humeral range of motion [44].
Patients with frozen shoulder present with altered shoulder muscle activity and kinematics [78].
Pathomechanics of frozen shoulder are characterized by glenohumeral motion limitations, high tension in the anteroinferior glenohumeral capsule, and altered scapular motion [75].
The scapulohumeral rhythm (SHR) of the affected shoulder is inversely related to the severity of limitation of shoulder range of motion, suggesting a compensatory pattern [80].
The anatomical structure of passive shoulder restraints has no impact on the difference in passive joint position sense values between external and internal rotation in frozen shoulder [59].
The thickness of the inferior glenohumeral joint capsule in the 80° scapular plane elevated arm position is a highly reliable and valid method for assessment [79].
Imaging is an essential tool for evaluation of patients with shoulder pain to understand the extent of injury [37].
X-rays in frozen shoulder are normal, and their main role is to exclude other causes of pain and stiffness [4].
Post-traumatic stiffness may persist for some months after severe shoulder injury but is maximal at the start and gradually lessens, unlike the pattern of frozen shoulder [4].
Disuse stiffness can occur if the arm is nursed overcautiously, such as following a wrist fracture, but lacks the characteristic pain pattern of frozen shoulder [4].
Complex regional pain syndrome may follow acute trauma or be seen in patients with myocardial infarction or stroke, presenting features similar to frozen shoulder [4].
Rheumatoid arthritis and osteoarthritis can affect the shoulder and develop bilaterally, with diagnosis usually obvious on X-ray [4].
Shoulder stiffness is a typical outcome after bone or soft tissue injuries around the shoulder, including contusions, subluxations, dislocations, acromioclavicular joint injuries, clavicle and scapula fractures, and proximal humerus fractures in the elderly [61].
Repetitive, low-level trauma can cause localized contractures leading to motion loss in specific patterns [61].
Isolated posterior capsular contracture is the most commonly described localized contracture causing motion loss [61].
Surgical procedures such as anterior or posterior capsulorrhaphy, inferior capsular shift, and rotator cuff surgery can result in limitation of motion [61].

Classification

Frozen shoulder is a specific, painful, and debilitating condition affecting patients mainly in middle age [6].
Most patients clinically diagnosed with primary frozen shoulder had undiagnosed systemic abnormalities and/or intra-articular pathologies [5].
18F-FDG PET/CT is clinically relevant in diagnostically challenging cases, such as distinguishing the first phase of frozen shoulder from subacromial impingement [11].
Health professionals manage frozen shoulders differently for different phases of the condition [16].
Primary frozen shoulders are defined by total elevation restricted to 135° or less [20].
In primary frozen shoulder, the restriction of motion is localized to the humero-scapular joint [20].
Primary frozen shoulder is diagnosed when no findings in case history, clinical examination, or radiological examination explain the decrease in range of motion [20].
Cases with post-traumatic conditions, rheumatoid arthritis, osteoarthritis, hemiplegia, and other obvious changes are excluded from primary frozen shoulder classification [20].
Secondary frozen shoulder is characterized by decreased range of motion following a traumatic lesion [20].
Associated injuries in secondary frozen shoulder include soft tissue injury to the shoulder region, intra- and juxtaarticular fractures, and other fractures of the upper limb [20].
Frozen shoulder is classified into three consecutive stages according to Reeves [20].
Stage 1 of frozen shoulder is characterized by pain [20].
Stage 1 of frozen shoulder has a duration of 10 to 36 weeks [20].
In Stage 1 of frozen shoulder, there is no difference between men and women, no difference between affected dominant and nondominant shoulders, and no correlation with age [20].
In the early stages of frozen shoulder, there is a full range of movement under anesthesia [20].
Classification of frozen shoulder was found to be controversial [38].
There are lower rates of agreement among Japan Shoulder Society (JSS) members than American Shoulder and Elbow Surgeons (ASES) members for the definition of primary frozen shoulder [43].
There are lower rates of agreement among JSS members than ASES members for the classification of primary and secondary frozen shoulder [43].
There are lower rates of agreement among JSS members than ASES members for the divisions of secondary frozen shoulder [43].
There is disagreement among shoulder specialists regarding terminology for frozen shoulder [57].

Clinical Presentation

Frozen shoulder is a specific, painful, and debilitating condition that primarily affects patients in middle age [6].
Frozen shoulder is a common disease that causes significant morbidity [21].
Frozen shoulder is characterized by severe shoulder pain and functional restriction [24].
Frozen shoulder has considerable economic impact [28].
Frozen shoulder typically involves substantial pain, movement restriction, and considerable morbidity [12].
Frozen shoulder affects approximately 4% of the general population [24].
Frozen shoulder affects up to 59% of patients with diabetes mellitus [24].
The disease duration of frozen shoulder varies between 1 and 3 years [24].
The clinical course of primary (idiopathic) frozen shoulder consists of three phases: pain, stiffness, and thawing [3].
Primary frozen shoulder is characterized by progressive pain and stiffness which usually resolves spontaneously after about 18 months [4].
In Phase I (Pain), patients experience a gradual onset of diffuse shoulder pain that is progressive over weeks to months [3].
The pain in Phase I is usually worse at night and exacerbated by lying on the affected side [3].
In Phase II (Stiffness), patients restrict movement to seek pain relief, leading to stiffness that usually lasts 4 to 12 months [3].
During Phase II, patients have difficulty with activities of daily living, such as men reaching back pockets or women fastening brassieres [3].
In Phase II, a dull ache is present nearly all the time, especially at night, often accompanied by sharp pain during range of motion at or near new endpoints [3].
In Phase III (Thawing), motion increases and pain diminishes over weeks or months [3].
Without treatment, motion return in Phase III is gradual and may never objectively return to normal, though patients often subjectively feel near normal [3].
The natural history of frozen shoulder involves pain that increases in severity, prevents sleeping on the affected side, and subsides after several months [4].
As pain subsides in frozen shoulder, stiffness becomes more prominent and persists for another 6–12 months if untreated [4].
Movement is gradually regained in frozen shoulder but may not return to normal [4].
Patients with frozen shoulder are typically aged 40–60 years [4].
Patients with frozen shoulder may give a history of trauma, often trivial, followed by pain [4].
Physical examination of frozen shoulder usually reveals slight muscle wasting and tenderness [4].
Movements in frozen shoulder are always limited, and the shoulder may be extremely stiff in severe cases [4].
X-rays in frozen shoulder are normal; their main role is to exclude other causes of pain and stiffness [4].
Post-traumatic stiffness is characterized by stiffness without much pain that is maximal at the start and gradually lessens, unlike the pattern of frozen shoulder [4].
Disuse stiffness occurs if the arm is nursed overcautiously and lacks the characteristic pain pattern of frozen shoulder [4].
Complex regional pain syndrome may follow acute trauma or occur in patients with myocardial infarction or stroke, presenting features similar to frozen shoulder [4].
Rheumatoid arthritis and osteoarthritis can affect the shoulder bilaterally and are usually obvious on X-ray [4].
Primary frozen shoulder excludes cases with post-traumatic conditions, rheumatoid arthritis, osteoarthritis, hemiplegia, or other obvious changes in history or examination [20].
Secondary frozen shoulder involves decreased range of motion following a traumatic lesion, such as soft tissue injury or fractures of the upper limb [20].
Stage 1 (pain) of frozen shoulder lasts 10 to 36 weeks [20].
In Stage 1 of frozen shoulder, there is no difference in presentation between men and women, affected dominant and nondominant shoulders, or correlation with age [20].
Frozen shoulder following COVID-19 vaccination may present with clinical features similar to idiopathic frozen shoulder [39].
Frozen shoulder can occur after COVID-19 vaccination [41].
Frozen shoulder is particularly associated with diabetes, Dupuytren’s disease, hyperlipidaemia, hyperthyroidism, cardiac disease, and hemiplegia [4].
MR findings in frozen shoulder should not replace clinical judgments regarding further prognosis and treatment decisions [7].
Unusual stiffness and pain in the shoulder of a young female patient suggests a wide range of disease entities, including infection [23].
Misdiagnosing shoulder tumors as frozen shoulder syndrome is likely to cause a significant delay in making a correct diagnosis [40].
A detailed clinical history and examination is critical in the assessment of a painful, stiff shoulder to avoid misdiagnosis of conditions like malignant shoulder girdle tumours [1].

Investigations

A detailed clinical history and examination is critical in the assessment of a painful, stiff shoulder [1].
The term frozen shoulder should be reserved for a well-defined disorder characterized by progressive pain and stiffness which usually resolves spontaneously after about 18 months [4].
The histological features of frozen shoulder are reminiscent of Dupuytren’s disease, with active fibroblastic and myofibroblastic proliferation in the rotator interval, anterior capsule and coracohumeral ligament [4].
Patients may give a history of trauma, often trivial, followed by pain that gradually increases in severity and often prevents sleeping on the affected side [4].
Pain begins to subside after several months, but stiffness becomes more problematic; untreated stiffness persists for another 6–12 months before movement is gradually regained, which may not return to normal [4].
Clinical examination usually reveals slight muscle wasting and tenderness, with always limited movements and extreme stiffness in severe cases [4].
X-rays are normal in frozen shoulder, and their main role is to exclude other causes of pain and stiffness [4].
Disuse stiffness may occur if the arm is nursed overcautiously, such as following a wrist fracture, and lacks the characteristic pain pattern of frozen shoulder [4].
Complex regional pain syndrome may follow acute trauma or be seen in patients with myocardial infarction or stroke, and its features can be similar to those of frozen shoulder [4].
Both rheumatoid arthritis and osteoarthritis can affect the shoulder, with diagnosis usually obvious on X-ray, and rheumatoid arthritis may present with characteristic generalized symptoms and signs [4].
Unusual stiffness and pain in the shoulder of a young female patient suggests a wide range of disease entities, from simple frozen shoulder to infection [23].
Routine use of shoulder MRI scans in patients with frozen shoulder but without suspicion of additional pathology may not be indicated [31].
Imaging is an essential tool for evaluation of patients with shoulder pain, and understanding the extent of an injury with imaging is key to successful management [37].
Physicians should re-examine frozen shoulder patients with repeated plain radiographs and further imaging, especially MRI, if conservative therapy fails [56].
MR arthrography reveals characteristic findings in patients with frozen shoulder [58].
T2 signal hyperintensity and axillary capsule thickening are characteristic of the early stages of frozen shoulder, although MRI alone cannot completely define the disease stage [71].
The burning sign is an abnormal finding that appears in dynamic MRI of severe frozen shoulder [73].
Dynamic MRI semiquantitatively demonstrated a reduction in abnormal blood flow and improvement in clinical results after manipulation under cervical nerve root block (MUC) in patients with frozen shoulder [77].
Clinical improvement in patients with frozen shoulder was associated with a decrease in the coefficient of enhancement (CE) in the glenohumeral synovium following intraarticular injections of hyaluronate [81].
There may be a causal relationship between hypothyroidism and frozen shoulder [85].
Patients who underwent image-guided (ultrasound) injections had statistically significant greater improvement in shoulder pain and function at 6 weeks after injection compared to blind injections [86].
MR imaging of patients with severe frozen shoulder after MUC showed 29 capsule tears, 4 labrum tears, and 15 bone bruises of the humeral head [87].

Treatment

Non-Operative Management

Treatment for frozen shoulder aims to improve pain and function through a shared decision-making process, utilizing a step-up approach from conservative measures to invasive treatments if symptoms persist [28].
Health professionals manage frozen shoulders differently depending on the phase of the condition [16].
There is limited evidence of the effectiveness of different forms of treatment used for frozen shoulder, with many studies carrying a moderate to high risk of bias and omitting details of symptom duration or condition phase [74].
The variety of participants, methods, interventions, and outcomes across trials provides limited new evidence to inform non-surgical management [14].
Conservative treatment is effective for the treatment of frozen shoulder regardless of the severity of symptoms [45].
Intra-articular steroid injection is effective and safe for frozen shoulder, relieving pain, improving functional performance, and increasing range of motion [48].
Multisite corticosteroid injection therapy is more effective than single intra-articular injection in terms of pain relief, restoration of motion, and functional status for primary frozen shoulder [46].
Both multisite and single glenohumeral injections of corticosteroid are effective in patients with primary frozen shoulder [49].
Ultrasound-guided administration of corticosteroid injections into the glenohumeral joint increases the likelihood of successful injection but does not improve clinical outcomes at 12 weeks compared with blind administration [52].
Ultrasound-guided multisite injection is a nonsurgical treatment technique for frozen shoulder that emphasizes correct injection sites [72].
Hydrodilatation has emerged as a potential nonsurgical option in the management of frozen shoulder, but its role has yet to be fully clarified [60].
Management of frozen shoulder stage II to III using hydrodistension and a guided exercise programme by physiotherapists in primary care is an effective non-operative treatment strategy [66].
Recurrence of frozen shoulder after hydrodilatation was more common in primary (33%) versus secondary (16%) frozen shoulder [34].
A central nervous system-focused treatment approach is being evaluated in a randomized clinical trial to compare effectiveness against standard medical and physical therapy care [42].
The comparative effectiveness of low-level laser therapy versus muscle energy technique is being evaluated in a randomized controlled trial to determine the optimal treatment approach for frozen shoulder related to diabetes [47].

Operative and Procedural Management

Secondary frozen shoulder may be more recalcitrant to conventional conservative treatment [64].
The study on arthroscopic capsular release timing adds information for shared decision-making but should not be a plea for surgery for patients with a mean duration of symptoms of 4 months; a strict definition of recalcitrant idiopathic frozen shoulder is needed to prevent unnecessary interventions [10].
The arthroscopic 360° release is an effective and safe treatment modality for severe or recalcitrant frozen shoulder [53].
A combination of limited capsular release and manipulation under anaesthesia (MUA) for primary frozen shoulder is a safe and effective procedure resulting in marked improvement in pain, function, and range of motion [55].
The mid-term outcomes of transcatheter arterial micro embolization (TAME) for frozen shoulders resistant to conservative treatments are encouraging and warrant further evaluation [50].
Manipulation under anesthesia versus physiotherapy treatment in stage two of a frozen shoulder is being evaluated in a randomized controlled trial to provide evidence on the best treatment strategy [51].
Different treatment strategies for frozen shoulder may be appropriate depending on the location of pathology [9].

Complications

Frozen shoulder is a painful and debilitating condition [6].
Frozen shoulder causes significant morbidity [21].
The natural history of primary frozen shoulder consists of three phases: pain, stiffness, and thawing [3].
Primary frozen shoulder usually resolves spontaneously after about 18 months [4].
Without treatment, motion return in primary frozen shoulder is gradual and may never objectively return to normal [3].
In the long term, 41% of patients with frozen shoulder report some ongoing symptoms [30].
Postoperative frozen shoulder is a serious complication after shoulder surgery with an incidence of 11% [54].
Preoperative frozen shoulder negatively affects functional outcomes, including range of motion, at 6 months and 1 year postoperatively following arthroscopic rotator cuff repair [33].
Preoperative frozen shoulder positively affects rotator cuff healing [33].
Patients with diabetes should be monitored more closely for frozen shoulder, as they may experience persistent pain or lack of function long-term [8].
An age between 46 and 60 years is a statistically significant risk factor for developing frozen shoulder after simple arthroscopic shoulder procedures [29].
A previous history of contralateral frozen shoulder is a statistically significant risk factor for developing frozen shoulder after simple arthroscopic shoulder procedures [29].
Most patients clinically diagnosed with primary frozen shoulder have undiagnosed systemic abnormalities and/or intra-articular pathologies [5].
Recurrence of frozen shoulder after manipulation under anaesthetic (MUA) can occur, but late recurrence is uncommon [22].
Patients with poor outcomes or recurrent symptoms after MUA can be offered a further MUA with an expectation of good outcome and low complication rate [17].

Recovery

Phase I (Pain) involves a gradual onset of diffuse shoulder pain that is progressive over weeks to months [3].
Pain in Phase I is usually worse at night and exacerbated by lying on the affected side [3].
Phase II (Stiffness) usually lasts 4 to 12 months [3].
During Phase II, patients restrict movement to seek pain relief, leading to difficulty with activities of daily living such as reaching back pockets or fastening brassieres [3].
Phase II is accompanied by a dull ache present nearly all the time, especially at night, and sharp pain during range of motion at or near new endpoints [3].
Phase III (Thawing) lasts for weeks or months, during which motion increases and pain diminishes [3].
Without treatment, motion return in Phase III is gradual in most patients [3].
Objective motion may never return to normal, although most patients subjectively feel near normal due to compensation or adjustment in activities of daily living [3].
Frozen shoulder affects approximately 4% of the general population and up to 59% in patients with diabetes mellitus [24].
In the long term, 59% of patients with frozen shoulder have normal or near normal shoulders [30].
94% of patients with spontaneous frozen shoulder recover to normal levels of function and motion without treatment [69].
Idiopathic frozen shoulder is a self-limiting condition in which symptoms subside and full shoulder movement returns within a maximum of two years from the onset of symptoms [88].
Long-term outcome after manipulation under anaesthetic (MUA) for frozen shoulder is favourable with late recurrence being uncommon [22].
Patients with poor outcome or recurrent symptoms after MUA should be offered a further MUA with the expectation of a good outcome and a low complication rate [17].
Arthroscopic capsular release leads to a faster and long-lasting recovery in patients with refractory primary frozen shoulder syndrome [35].
The long-term results of arthroscopic capsular release in frozen shoulder were confirmed in 255 patients [36].
MUA in stage 2 frozen shoulder results in a faster recovery of range of motion and improved functional outcome compared to physiotherapy alone in the short term [68].
MUA in stage 2 frozen shoulder can be considered safe compared to physiotherapy alone in the short term [68].
Early surgical intervention might shorten the overall duration of symptoms in frozen shoulder [19].
Early surgical intervention is not associated with inferior clinical outcomes when compared with late surgical intervention [19].
Timing has a significant influence on the outcome of manipulation for frozen shoulders [90].
Diabetes is a poor prognostic factor for the conservative treatment of frozen shoulder [82].
Male sex is a poor prognostic factor for the conservative treatment of frozen shoulder [82].
Simultaneous bilateral involvement is a poor prognostic factor for the conservative treatment of frozen shoulder [82].
Subsequent bilateral involvement is a poor prognostic factor for the conservative treatment of frozen shoulder [82].
A longer duration of symptoms recorded at the first visit is a poor prognostic factor for the conservative treatment of frozen shoulder [82].
Preoperative frozen shoulder negatively affected most functional outcomes, including range of motion, at 6 months and 1 year postoperatively after arthroscopic rotator cuff repair [33].
Preoperative frozen shoulder positively affected rotator cuff healing after arthroscopic rotator cuff repair [33].

Key Evidence

[L4] A detailed clinical history and examination is critical in the assessment of a painful, stiff shoulder. [1] (10.1186/1477-7800-2-2)
[L1] This updated guideline provides evidence-based guidance for managing frozen shoulder and identifies key areas for future research. [2] (10.1177/17585732251335955)
[L4] Most patients clinically diagnosed with primary frozen shoulder had undiagnosed systemic abnormalities and/or intra-articular pathologies. [5] (10.5397/cise.2018.21.2.82)
[Paper] Frozen shoulder is a specific, painful and debilitating condition effecting patients mainly in middle age. [6] (10.1016/j.maturitas.2014.02.009)
[L4] MR findings in frozen shoulder should not replace clinical judgments regarding further prognosis and treatment decisions. [7] (10.1007/s00167-015-3887-y)
[L2] If high-quality studies can confirm the findings of this review, then clinicians should monitor frozen shoulder patients with diabetes more closely and offer further treatment if pain or lack of function persist long-term. [8] (10.1016/j.arrct.2021.100141)
[L5] Different treatment strategies for frozen shoulder may be appropriate, depending on the location. [9] (10.1016/j.jse.2018.03.010)
[L5] The study adds information for shared decision-making but should not be a plea for surgery for patients with a mean duration of symptoms of 4 months; a strict definition of recalcitrant idiopathic frozen shoulder is needed to prevent unnecessary interventions. [10] (10.1177/2325967120903710)
[L2] This is clinically relevant in diagnostically challenging cases, for instance in the first phase of frozen shoulder, which can be difficult to distinguish from subacromial impingement. [11] (10.1007/s00167-020-05937-2)
[L5] Frozen shoulder is a poorly understood condition that typically involves substantial pain, movement restriction, and considerable morbidity. [12] (10.1016/j.math.2014.07.006)
[L1] The variety of participants included/excluded in trials and the variety of methods, interventions and outcomes used across the trials provided limited new evidence to inform the non-surgical management and treatment of people with frozen shoulder. [14] (10.2340/16501977-2578)
[L4] The etiology of frozen shoulder is still not known and our understanding of the pathogenesis is limited. [15] (10.3109/03009749009096786)
[L4] Health professionals manage frozen shoulders differently for different phases of the condition. [16] (10.1111/j.1758-5740.2010.00073.x)
[L4] Patients with a poor outcome or recurrent symptoms of a frozen shoulder after a MUA should be offered a further MUA with the expectation of a good outcome and a low complication rate. [17] (10.1302/0301-620x.99b6.bjj-2016-1133.r1)
[L3] Early surgical intervention might shorten the overall duration of symptoms in frozen shoulder and is not associated with inferior clinical outcomes when compared with late surgical intervention. [19] (10.1016/j.jse.2020.07.023)
[L4] Frozen shoulder is a common disease which causes significant morbidity. [21] (10.5312/wjo.v6.i2.263)
[L3] Long-term outcome after MUA for frozen shoulder is favourable with late recurrence being uncommon. [22] (10.1177/17585732211070007)
[L5] Unusual stiffness and pain in the shoulder of a young female patients suggests a wide range of disease entities, from simple frozen shoulder to (albeit rarely) infection. [23] (10.1016/j.radcr.2020.08.006)
[L1] This systematic review presents a summary of what is currently known about the tissue pathophysiology of primary frozen shoulder. [25] (10.1186/s12891-016-1190-9)
[L4] Frozen shoulder is a painful and debilitating condition with considerable economic impact; treatment aims to improve pain and function through a shared decision-making process, with a step-up approach from conservative measures to invasive treatments if symptoms persist. [28] (10.1177/1758573215601779)
[L3] An age of between 46 and 60 years and a previous history of contralateral frozen shoulder were statistically significant risk factors. [29] (10.1302/0301-620x.97b7.35387)
[L3] In the long term, 59% of patients had normal or near normal shoulders and 41% reported some ongoing symptoms. [30] (10.1016/j.jse.2007.05.009)
[L4] Therefore, routine use of shoulder MRI scans in patients with FS but without suspicion of an additional pathology may not be indicated. [31] (10.1016/j.jseint.2022.05.009)
[L1] There is insufficient evidence to reliably recommend a treatment approach for frozen shoulder. [32] (10.1136/bmj.i4162)
[L3] Preoperative frozen shoulder positively affected rotator cuff healing but negatively affected most functional outcomes, including ROM, at 6 months and 1 year postoperatively. [33] (10.1177/2325967120934449)
[L4] Further treatment was indicated in 41% of patients who could not tolerate more than 20 mL of injection, and recurrence was more common in primary (33%) versus secondary (16%) frozen shoulder. [34] (10.1177/17585732221124914)
[Paper] In patients with refractory primary frozen shoulder syndrome, arthroscopic capsular release emerges as a suitable option that leads to a faster and long-lasting recovery. [35] (10.1016/j.eats.2015.06.004)
[L4] The long-term results of arthroscopic capsular release in frozen shoulder were confirmed in 255 patients. [36] (10.1186/s13018-018-0758-5)
[L4] Imaging is an essential tool for evaluation of patients with shoulder pain; understanding the extent of an injury with imaging is key to successful management. [37] (10.1016/j.csm.2013.03.009)
[L4] However, classification of frozen shoulder was found to be controversial. [38] (10.4055/cios.2020.12.1.60)
[L4] Frozen shoulder following COVID-19 vaccination may present with clinical features similar to those of idiopathic frozen shoulder. [39] (10.1016/j.xrrt.2023.09.013)
[L2] Misdiagnosing shoulder tumors as frozen shoulder syndrome is likely to cause a significant delay in making a correct diagnosis. [40] (10.1016/j.jse.2009.05.010)
[L4] Frozen shoulder can occur after COVID-19 vaccination, and musculoskeletal specialists should be aware of this diagnosis to identify and treat such patients early. [41] (10.1016/j.jseint.2022.02.013)
[Paper] The trial aims to compare the effectiveness of a CNS-directed treatment program versus standard medical and physical therapy care on outcomes in participants with frozen shoulder. [42] (10.1186/s13063-019-3585-z)
[L4] The survey shows lower rates of agreement among the JSS members than the ASES members for the definition of primary frozen shoulder, the classification of primary and secondary frozen shoulder, and the divisions of secondary frozen shoulder. [43] (10.1016/j.jos.2018.12.012)
[L4] Symptomatic subjects demonstrated substantial kinematic deficits during humeral range of motion. [44] (10.1016/s0003-9993(03)00359-9)
[L3] Conservative treatment is effective for the treatment of frozen shoulder. [45] (10.1016/j.asmr.2025.101149)
[Commentary] Multisite corticosteroid injection therapy is more effective in terms of pain relief, restoration of motion, and functional status than single intra-articular injection for the treatment of primary frozen shoulder. [46] (10.1016/j.arthro.2021.02.028)
[L2] The findings of the study may provide evidence on the efficacy of these interventions and most likely, the optimal treatment approach for frozen shoulder related to diabetes, which may guide clinical practice. [47] (10.1186/s13018-024-04735-7)
[L1] Intra-articular steroid injection is effective and safe for frozen shoulder, relieving pain, improving functional performance, and increasing range of motion. [48] (10.1177/0363546516669944)
[L1] Both treatments were effective in patients with primary frozen shoulder. [49] (10.1016/j.arthro.2021.01.069)
[Abstract] The mid-term outcomes of TAME for frozen shoulders that were resistant to conservative treatments are encouraging and warrant further evaluation. [50] (10.1016/j.jse.2016.11.031)
[L2] Successful completion of this trial will provide evidence on the best treatment strategy for patients with a stage two frozen shoulder. [51] (10.1186/s12891-017-1763-2)
[L1] In patients with frozen shoulder, US-guided administration of corticosteroid injections into the glenohumeral joint increased the likelihood of successful injection but did not improve clinical outcomes at 12 weeks compared with blind administration. [52] (10.2106/jbjs.21.01007)
[L4] The arthroscopic 360° release is an effective and safe treatment modality for severe or recalcitrant frozen shoulder. [53] (10.1016/j.jseint.2024.07.006)
[L2] Postoperative frozen shoulder is a serious complication after shoulder surgery, with an incidence of 11%. [54] (10.1007/s00402-016-2589-3)
[L4] A combination of limited capsular release and MUA for the treatment of primary frozen shoulder is a safe and effective procedure resulting in marked improvement in pain, function and range of motion. [55] (10.1177/1758573215578590)
[L4] Physicians should re-examine frozen shoulder patients with repeated plain radiographs and further imaging, especially MRI, if conservative therapy fails. [56] (10.1016/j.jse.2011.07.026)
[L4] This survey summarized the trend in prevalent practices regarding frozen shoulder among shoulder specialists and senior shoulder surgeons of SESI, revealing strong consensus on imaging and nonoperative management but disagreement on terminology and specific surgical complications. [57] (10.1177/23259671221118834)
[L4] MR arthrography reveals characteristic findings in patients with frozen shoulder. [58] (10.1148/radiol.2332031219)
[L3] The anatomical structure of passive shoulder restraints has no impact on the difference in passive joint position sense values between external and internal rotation. [59] (10.1186/s12891-016-0971-5)
[L5] Hydrodilatation has emerged as a potential nonsurgical option in the management of frozen shoulder, but its role has yet to be fully clarified. [60] (10.1302/2058-5241.2.160061)
[L5] This scoping review outlines the complexity of the pathophysiology of frozen shoulder and provides a comprehensive overview of pathophysiologic mechanisms. [62] (10.1186/s40634-020-00307-w)
[L4] Secondary frozen shoulder may be more recalcitrant to conventional conservative treatment. [64] (10.1016/j.jor.2015.01.030)
[L4] This service evaluation demonstrates that management of frozen shoulder stage II to III, as conducted by physiotherapists in a primary care setting utilizing hydrodistension and a guided exercise programme, represents an effective non-operative treatment strategy. [66] (10.1177/1758573217701063)
[L1] MUA in stage 2 frozen shoulder can be considered safe and results in a faster recovery of range of motion and improved functional outcome compared to physiotherapy alone in the short term. [68] (10.1016/j.jseint.2023.11.004)
[L4] We found 94% of patients with spontaneous frozen shoulder recovered to normal levels of function and motion without treatment. [69] (10.1007/s11999-011-2176-4)
[L5] MUA and ACR are good treatment options for primary frozen shoulder; MUA is simpler but carries risks of serious complications, while ACR may be safer if performed by experienced surgeons and is convenient for patients with combined rotator cuff tears. [70] (10.5397/cise.2020.00311)
[L5] T2 signal hyperintensity and axillary capsule thickening are characteristic of the early stages of frozen shoulder, although MRI alone cannot completely define the disease stage. [71] (10.1016/j.xrrt.2024.05.002)
[L5] This technique is presented for the nonsurgical treatment of frozen shoulder, emphasizing correct injection sites. [72] (10.1016/j.eats.2022.06.020)
[L4] The burning sign is an abnormal finding that appears in dynamic MRI of severe frozen shoulder. [73] (10.1016/j.jse.2016.06.003)
[L2] There is limited evidence of the effectiveness of different forms of treatment used for frozen shoulder, with many studies evaluating treatment effects carrying a moderate to high risk of bias and omitting details of the duration of symptoms or the phase of the condition. [74] (10.1111/j.1758-5740.2010.00067.x)
[L5] Pathomechanics of the frozen shoulder characterised by glenohumeral motion limitations should be considered complicated, as confirmed by high tension in the anteroinferior glenohumeral capsule and altered scapular motion. [75] (10.1016/j.jseint.2025.04.003)
[L4] Dynamic MRI semiquantitatively demonstrated a reduction in abnormal blood flow and improvement in clinical results after MUC in patients with frozen shoulder. [77] (10.1016/j.jseint.2021.12.007)
[L4] Patients with frozen shoulder presented with altered shoulder muscle activity and kinematics, and one-session of heat and manual muscle release showed beneficial effects on shoulder muscle performance, kinematics, mobility, and pain. [78] (10.1186/s12891-017-1867-8)
[L3] The thickness of the inferior glenohumeral joint capsule in the 80° scapular plane elevated arm position was shown to be a highly reliable and valid method. [79] (10.1016/j.jseint.2024.06.004)
[L4] SHR of the affected shoulder is inversely related to severity of limitation of shoulder range of motion, which suggests a compensatory pattern. [80] (10.1016/j.jbiomech.2007.09.004)
[L4] Clinical improvement in patients with frozen shoulder was associated with a decrease in the coefficient of enhancement (CE) in the glenohumeral synovium. [81] (10.1007/s00776-004-0766-7)
[L2] Diabetes, male sex, simultaneous bilateral involvement, subsequent bilateral involvement, and a longer duration of symptoms recorded at the first visit were identified as poor prognostic factors for the conservative treatment of frozen shoulder. [82] (10.1016/j.jos.2019.03.011)
[L2] Our MR analysis suggests that there may be a causal relationship between hypothyroidism and frozen shoulder. [85] (10.1186/s12891-024-07826-y)
[L1] Patients who underwent image-guided (ultrasound) injections had statistically significant greater improvement in shoulder pain and function at 6 weeks after injection compared to blind injections. [86] (10.1186/1471-2474-12-137)
[L4] MR imaging of patients with severe frozen shoulder after MUC showed 29 capsule tears, 4 labrum tears, and 15 bone bruises of the humeral head. [87] (10.1016/j.jse.2015.06.019)
[L4] In the great majority of patients idiopathic frozen shoulder is a self-limiting condition, in which symptoms subside and full shoulder movement returns within a maximum of two years from the onset of symptoms. [88] (10.2106/00004623-197860040-00030)
[L4] In the great majority of patients idiopathic frozen shoulder is a self-limiting condition, in which symptoms subside and full shoulder movement returns within a maximum of two years from the onset of symptoms. [89] (10.2106/00004623-197860040-00029)
[L4] Timing has a significant influence on the outcome of manipulation for frozen shoulders. [90] (10.1016/j.jos.2020.11.002)

References

[1] Lessons learnt from the painful shoulder; a case series of malignant shoulder girdle tumours misdiagnosed as frozen shoulder. International Seminars in Surgical Oncology. 2005. DOI: 10.1186/1477-7800-2-2

[2] British Elbow and Shoulder Society patient care pathway: Frozen shoulder. Shoulder & Elbow. 2025. DOI: 10.1177/17585732251335955

[3] Campbell S Operative Orthopaedics 4 Volume Set. ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION WITH BONE-PATELLAR TENDON-BONE GRAFT > PRIMARY FROZEN SHOULDER.

[4] Apley And Solomon S Concise System Of Orthopaedics And Trauma. ADHESIVE CAPSULITIS (FROZEN SHOULDER).

[5] Is the Frozen Shoulder Classification a Reliable Assessment?. Clinics in Shoulder and Elbow. 2018. DOI: 10.5397/cise.2018.21.2.82

[6] Frozen shoulder – A stiff problem that requires a flexible approach. Maturitas. 2014. DOI: 10.1016/j.maturitas.2014.02.009

[7] Correlations of magnetic resonance imaging findings with clinical symptom severity and prognosis of frozen shoulder. Knee Surgery, Sports Traumatology, Arthroscopy. 2015. DOI: 10.1007/s00167-015-3887-y

[8] Diabetes as a Prognostic Factor in Frozen Shoulder: A Systematic Review. Archives of Rehabilitation Research and Clinical Translation. 2021. DOI: 10.1016/j.arrct.2021.100141

[9] Comparative proteome analysis of the capsule from patients with frozen shoulder. Journal of Shoulder and Elbow Surgery. 2018. DOI: 10.1016/j.jse.2018.03.010

[10] What Is the Right Timing for Arthroscopic Capsular Release of a Frozen Shoulder? Letter to the Editor. Orthopaedic Journal of Sports Medicine. 2020. DOI: 10.1177/2325967120903710

[11] The role of ¹⁸F‐FDG PET/CT in the diagnosis of frozen shoulder. Knee Surgery, Sports Traumatology, Arthroscopy. 2020. DOI: 10.1007/s00167-020-05937-2

[12] Frozen shoulder contracture syndrome – Aetiology, diagnosis and management. Manual Therapy. 2015. DOI: 10.1016/j.math.2014.07.006

[14] Clinical effectiveness of non-surgical interventions for primary frozen shoulder: A systematic review. Journal of Rehabilitation Medicine. 2019. DOI: 10.2340/16501977-2578

[15] Frozen Shoulder: Current Concepts. Scandinavian Journal of Rheumatology. 1990. DOI: 10.3109/03009749009096786

[16] Managing Idiopathic Frozen Shoulder: A Survey of Health Professionals' Current Practice and Research Priorities. Shoulder & Elbow. 2010. DOI: 10.1111/j.1758-5740.2010.00073.x

[17] Recurrence of frozen shoulder after manipulation under anaesthetic (MUA). The Bone & Joint Journal. 2017. DOI: 10.1302/0301-620x.99b6.bjj-2016-1133.r1

[19] Does the timing of surgical intervention impact the clinical outcomes and overall duration of symptoms in frozen shoulder?. Journal of Shoulder and Elbow Surgery. 2021. DOI: 10.1016/j.jse.2020.07.023

[20] Classifications And Scores Of The Shoulder. Classifications of frozen shoulder.

[21] Frozen shoulder: A systematic review of therapeutic options. World Journal of Orthopedics. 2015. DOI: 10.5312/wjo.v6.i2.263

[22] Long-Term Outcomes Following Manipulation Under Anaesthetic for Patients with Primary and Secondary Frozen Shoulder. Shoulder & Elbow. 2021. DOI: 10.1177/17585732211070007

[23] Subscapularis pyomyositis presenting as shoulder stiffness mistaken as frozen shoulder in young female: a case report. Radiology Case Reports. 2020. DOI: 10.1016/j.radcr.2020.08.006

[24] Frozen Shoulder. 2024.

[25] The pathophysiology associated with primary (idiopathic) frozen shoulder: A systematic review. BMC Musculoskeletal Disorders. 2016. DOI: 10.1186/s12891-016-1190-9

[28] Frozen Shoulder. Shoulder & Elbow. 2015. DOI: 10.1177/1758573215601779

[29] Frozen shoulder after simple arthroscopic shoulder procedures. The Bone & Joint Journal. 2015. DOI: 10.1302/0301-620x.97b7.35387

[30] Long-term outcome of frozen shoulder. Journal of Shoulder and Elbow Surgery. 2008. DOI: 10.1016/j.jse.2007.05.009

[31] Is routine magnetic resonance imaging necessary in patients with clinically diagnosed frozen shoulder? Utility of magnetic resonance imaging in frozen shoulder. JSES International. 2022. DOI: 10.1016/j.jseint.2022.05.009

[32] What is the most effective treatment for frozen shoulder?. BMJ. 2016. DOI: 10.1136/bmj.i4162

[33] Effect of Preoperative Frozen Shoulder on Clinical Outcomes After Arthroscopic Rotator Cuff Repair. Orthopaedic Journal of Sports Medicine. 2020. DOI: 10.1177/2325967120934449

[34] Recurrence of the frozen shoulder after hydrodilatation, what is the true incidence?. Shoulder & Elbow. 2022. DOI: 10.1177/17585732221124914

[35] Primary Frozen Shoulder Syndrome: Arthroscopic Capsular Release. Arthroscopy Techniques. 2015. DOI: 10.1016/j.eats.2015.06.004

[36] Clinical outcome of arthroscopic capsular release for frozen shoulder: essential technical points in 255 patients. Journal of Orthopaedic Surgery and Research. 2018. DOI: 10.1186/s13018-018-0758-5

[37] Imaging of the Shoulder with Arthroscopic Correlation. Clinics in Sports Medicine. 2013. DOI: 10.1016/j.csm.2013.03.009

[38] Definition, Diagnosis, Treatment, and Prognosis of Frozen Shoulder: A Consensus Survey of Shoulder Specialists. Clinics in Orthopedic Surgery. 2020. DOI: 10.4055/cios.2020.12.1.60

[39] Frozen shoulder after COVID-19 vaccination versus idiopathic frozen shoulder: similar clinical features and functional improvement at 1-year follow-up. JSES Reviews, Reports, and Techniques. 2024. DOI: 10.1016/j.xrrt.2023.09.013

[40] Tumors masked as frozen shoulders: A retrospective analysis. Journal of Shoulder and Elbow Surgery. 2010. DOI: 10.1016/j.jse.2009.05.010

[41] Frozen shoulder after COVID-19 vaccination. JSES International. 2022. DOI: 10.1016/j.jseint.2022.02.013

[42] A central nervous system-focused treatment approach for people with frozen shoulder: protocol for a randomized clinical trial. Trials. 2019. DOI: 10.1186/s13063-019-3585-z

[43] Representative survey of frozen shoulder questionnaire responses from the Japan Shoulder Society: What are the appropriate diagnostic terms for primary idiopathic frozen shoulder, stiff shoulder or frozen shoulder?. Journal of Orthopaedic Science. 2019. DOI: 10.1016/j.jos.2018.12.012

[44] Shoulder kinematics in subjects with frozen shoulder11No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the author(s) or upon any organization with which the author(s) is/are associated.. Archives of Physical Medicine and Rehabilitation. 2003. DOI: 10.1016/s0003-9993(03)00359-9

[45] Conservative Treatment for Frozen Shoulder Is Effective Regardless of the Severity of Symptoms. Arthroscopy, Sports Medicine, and Rehabilitation. 2025. DOI: 10.1016/j.asmr.2025.101149

[46] Editorial Commentary: Corticosteroid Injections and Physical Therapy Are Effective First-Line Treatments for Frozen Shoulder. Arthroscopy: The Journal of Arthroscopic & Related Surgery. 2021. DOI: 10.1016/j.arthro.2021.02.028

[47] Comparative effectiveness of low-level laser therapy versus muscle energy technique among diabetic patients with frozen shoulder: a study protocol for a parallel group randomised controlled trial. Journal of Orthopaedic Surgery and Research. 2024. DOI: 10.1186/s13018-024-04735-7

[48] Intra-articular Steroid Injection for Frozen Shoulder: A Systematic Review and Meta-analysis of Randomized Controlled Trials With Trial Sequential Analysis. The American Journal of Sports Medicine. 2016. DOI: 10.1177/0363546516669944

[49] A Multisite Injection Is More Effective Than a Single Glenohumeral Injection of Corticosteroid in the Treatment of Primary Frozen Shoulder: A Randomized Controlled Trial. Arthroscopy: The Journal of Arthroscopic & Related Surgery. 2021. DOI: 10.1016/j.arthro.2021.01.069

[50] Mid-term outcomes of prospective clinical trial of transcatheter arterial micro embolization (TAME) for resistant frozen shoulder. Journal of Shoulder and Elbow Surgery. 2017. DOI: 10.1016/j.jse.2016.11.031

[51] Manipulation under anesthesia versus physiotherapy treatment in stage two of a frozen shoulder: a study protocol for a randomized controlled trial. BMC Musculoskeletal Disorders. 2017. DOI: 10.1186/s12891-017-1763-2

[52] In Frozen Shoulder, US-Guided Versus Blind Administration of Intra-Articular Corticosteroid Injections Increased Accuracy of Injections but Did Not Improve Clinical Outcomes at 12 Weeks. Journal of Bone and Joint Surgery. 2021. DOI: 10.2106/jbjs.21.01007

[53] The clinical course and outcomes following arthroscopic frozen shoulder 360° release. JSES International. 2024. DOI: 10.1016/j.jseint.2024.07.006

[54] Incidence and prognostic factors for postoperative frozen shoulder after shoulder surgery: a prospective cohort study. Archives of Orthopaedic and Trauma Surgery. 2017. DOI: 10.1007/s00402-016-2589-3

[55] Limited capsular release and controlled manipulation under anaesthesia for the treatment of frozen shoulder. Shoulder & Elbow. 2015. DOI: 10.1177/1758573215578590

[56] Glenohumeral joint tuberculosis that mimics frozen shoulder: a retrospective analysis. Journal of Shoulder and Elbow Surgery. 2012. DOI: 10.1016/j.jse.2011.07.026

[57] Trends in Practice Among Shoulder Specialists in the Management of Frozen Shoulder: A Consensus Survey. Orthopaedic Journal of Sports Medicine. 2022. DOI: 10.1177/23259671221118834

[58] Frozen Shoulder: MR Arthrographic Findings. Radiology. 2004. DOI: 10.1148/radiol.2332031219

[59] Shoulder proprioception – lessons we learned from idiopathic frozen shoulder. BMC Musculoskeletal Disorders. 2016. DOI: 10.1186/s12891-016-0971-5

[60] Indications for hydrodilatation for frozen shoulder. EFORT Open Reviews. 2017. DOI: 10.1302/2058-5241.2.160061

[61] Rockwood And Matsen S The Shoulder. Arthroscopic Management of Prearthritic and Arthritic Conditions of the Shoulder and the Postarthroplasty Shoulder > Secondary Frozen Shoulder.

[62] The puzzling pathophysiology of frozen shoulders – a scoping review. Journal of Experimental Orthopaedics. 2020. DOI: 10.1186/s40634-020-00307-w

[64] The management of secondary frozen shoulder after anterior shoulder dislocation – The results of manipulation under anaesthesia and injection. Journal of Orthopaedics. 2016. DOI: 10.1016/j.jor.2015.01.030

[66] The effectiveness of ultrasound guided hydrodistension and physiotherapy in the treatment of frozen shoulder/adhesive capsulitis in primary care: a single centre service evaluation. Shoulder & Elbow. 2017. DOI: 10.1177/1758573217701063

[68] Improved range of motion after manipulation under anesthesia versus physiotherapy for stage two frozen shoulder: a randomized controlled trial. JSES International. 2024. DOI: 10.1016/j.jseint.2023.11.004

[69] The Natural History of Idiopathic Frozen Shoulder: A 2- to 27-year Followup Study. Clinical Orthopaedics & Related Research. 2012. DOI: 10.1007/s11999-011-2176-4

[70] Arthroscopic capsular release versus manipulation under anesthesia for primary frozen shoulder. Clinics in Shoulder and Elbow. 2020. DOI: 10.5397/cise.2020.00311

[71] Can magnetic resonance imaging distinguish clinical stages of frozen shoulder? A state-of-the-art review. JSES Reviews, Reports, and Techniques. 2024. DOI: 10.1016/j.xrrt.2024.05.002

[72] Ultrasound Guıded Multisıte Injectıon Technıque in the Treatment of Frozen Shoulder. Arthroscopy Techniques. 2022. DOI: 10.1016/j.eats.2022.06.020

[73] Characteristics of dynamic magnetic resonance imaging of idiopathic severe frozen shoulder. Journal of Shoulder and Elbow Surgery. 2017. DOI: 10.1016/j.jse.2016.06.003

[74] An Overview of Factors Relevant to Undertaking Research and Reviews on the Effectiveness of Treatment for Frozen Shoulder. Shoulder & Elbow. 2010. DOI: 10.1111/j.1758-5740.2010.00067.x

[75] Pathomechanics of glenohumeral capsule and scapula in idiopathic frozen shoulder: a study using a three-dimensional finite element model. JSES International. 2025. DOI: 10.1016/j.jseint.2025.04.003

[77] Reduction of abnormal blood flow in frozen shoulder after shoulder manipulation under ultrasound-guided cervical nerve root block: semiquantitative analysis using dynamic magnetic resonance imaging. JSES International. 2022. DOI: 10.1016/j.jseint.2021.12.007

[78] The immediate effect of muscle release intervention on muscle activity and shoulder kinematics in patients with frozen shoulder: a cross-sectional, exploratory study. BMC Musculoskeletal Disorders. 2017. DOI: 10.1186/s12891-017-1867-8

[79] Inferior glenohumeral joint capsule thickness in frozen shoulder via ultrasonography. JSES International. 2024. DOI: 10.1016/j.jseint.2024.06.004

[80] Three-dimensional scapular kinematics and scapulohumeral rhythm in patients with glenohumeral osteoarthritis or frozen shoulder. Journal of Biomechanics. 2008. DOI: 10.1016/j.jbiomech.2007.09.004

[81] Synovial response to intraarticular injections of hyaluronate in frozen shoulder: a quantitative assessment with dynamic magnetic resonance imaging. Journal of Orthopaedic Science. 2004. DOI: 10.1007/s00776-004-0766-7

[82] Is frozen shoulder completely resolved at 2 years after the onset of disease?. Journal of Orthopaedic Science. 2020. DOI: 10.1016/j.jos.2019.03.011

[85] Causal associations of hypothyroidism with frozen shoulder: a two-sample bidirectional Mendelian randomization study. BMC Musculoskeletal Disorders. 2024. DOI: 10.1186/s12891-024-07826-y

[86] Image-guided versus blind corticosteroid injections in adults with shoulder pain: A systematic review. BMC Musculoskeletal Disorders. 2011. DOI: 10.1186/1471-2474-12-137

[87] Magnetic resonance imaging and short-term clinical results of severe frozen shoulder treated with manipulation under ultrasound-guided cervical nerve root block. Journal of Shoulder and Elbow Surgery. 2016. DOI: 10.1016/j.jse.2015.06.019

[88] Brief Note The Natural History of 'Idiopathic' Frozen Shoulder. The Journal of Bone & Joint Surgery. 1978. DOI: 10.2106/00004623-197860040-00030

[89] The natural history of 'idiopathic' frozen shoulder.. The Journal of Bone & Joint Surgery. 1978. DOI: 10.2106/00004623-197860040-00029

[90] Does the timing of shoulder manipulation under ultrasound-guided cervical nerve root block for frozen shoulder affect the clinical outcome?. Journal of Orthopaedic Science. 2022. DOI: 10.1016/j.jos.2020.11.002