髋膝关节文献精译荟萃（第156期）
本期目录：
1、松解后交叉韧带是否会影响全膝关节置换术后效果
2、功能性安全区比Lewinnek安全区有更大的优势：为什么Lewinnek安全区不总能有效预测关节稳定性
3、重新考虑全膝关节置换术中常规应用止血带的合理性
4、可溶性Pecam-1作为关节假体周围感染的生物标志物
5、阿司匹林预防全髋和全膝关节置换术后静脉血栓的临床有效性和安全性：关于RCT的系统综述和Meta分析
6、股骨头坏死围塌陷期：保髋最后的机会
7、关节镜治疗临界髋关节发育不良失败原因的多中心研究：注意Tönnis角
8、跑步过程中的伸髋肌力量、躯干姿势和伸膝肌的使用
9、婴幼儿DDH超声检查体位带来的差异：冠状面屈曲位VS冠状面中立位
10、髋臼周围截骨术后患者报告结果与股骨头覆盖率和髋臼方向的相关性：单中心队列研究
11、关节镜与开放性股骨髋臼撞击症的治疗：中长期结果的系统评价
第一部分：关节置换及保膝相关文献
文献1
松解后交叉韧带是否会影响全膝关节置换术后效果
译者：张轶超
背景：对于后交叉韧带（PCL）保留型假体的全膝置换手术（TKA），要想达到良好的功能可能需要通过松解后交叉韧带来达到软组织平衡。但是一直有意见认为当松解了PCL后，考虑到关节稳定性和临床效果是否就应该将后交叉保留型（CR）假体换成后稳定型（PS）假体。本文的目的就是确定松解PCL会不会影响CR假体TKA的效果。
方法：选取从2006年12月到2015年7月间由本文作者中最年长的医生(J.M.)完成的CR-TKA患者。通过西安大略和麦克马斯特大学骨关节炎指数评分（WOMAC）、膝关节协会临床等级系统（KSS）、简易生活质量问卷（SF-12）物理/精神混合评分及翻修率来评估临床效果。
结果：对行CR-TKA患者的观察显示，无论是未对PCL松解的还是部分松解的或完全切断的病例间各项评分均无明显差异（WOMAC评分：P=0.54；KSS评分：P=0.42；SF-12精神混合评分：P=0.89；SF-12物理混合评分：P=0.527）。
结论：本研究表明当做CR-TKA时，无论是完好保留PCL还是松解PCL其临床效果相近。医生更应该注重的是软组织平衡。做CR假体时，如果部分松解或完全切断了PCL也不必更换成PS假体。
Does Recession of the Posterior Cruciate Ligament Influence Outcome in Total Knee Arthroplasty?
Background: For a PCL-retaining (posterior cruciate ligament) total knee arthroplasty (TKA) to function suitably, proper soft tissue balancing, including PCL recession, is required. Yet, when the recession of the PCL is needed, there is still a debate as to whether a cruciate-retaining (CR) TKA should be converted to a posterior-stabilized TKA due to the concern of instability and poorer clinical outcomes. The purpose of this study is to determine whether recession of the PCL adversely affects clinical outcomes in patients who undergo CR TKA.
Methods: CR TKAs of the same design performed by the senior author (J.M.) were identified between December 2006 and July 2015. Clinical outcome measurements were collected and included the Western Ontario and McMaster Universities Osteoarthritis Index score, the Knee Society Clinical Rating System, Short Form-12 Physical Composite Score/Mental Health Composite Score, and revision rates.
Results: There were no significant differences in clinical outcome when the PCL was retained, partially recessed, or completely released during PCL-retaining TKA (Western Ontario and McMaster Universities Osteoarthritis Index: P = .54, Knee Society Clinical Rating System: P = .42, Short Form-12 Mental Health Composite Score: P = .89, Short Form-12 Physical Composite Score: P = .527).
Conclusion: This study presents evidence of similar clinical outcomes when the PCL is retained or released during PCL-retaining TKA, provided attention is paid to appropriate soft tissue balancing. CR TKA undergoing partial or complete release of the PCL should not routinely be converted to a posterior-stabilized knee design.
文献出处：Dion CB, Howard JL, Lanting BA, McAuley JP. Does Recession of the Posterior Cruciate Ligament Influence Outcome in Total Knee Arthroplasty? J Arthroplasty. 2019 Oct;34(10):2383-2387. doi: 10.1016/j.arth.2019.05.052. Epub 2019 Jun 5. PMID: 31326243.
文献2
功能性安全区比Lewinnek安全区有更大的优势：
为什么Lewinnek安全区不总能有效预测关节稳定性
译者：马云青
背景：以往提出的lewinnek“安全区”并不能很好的预测全髋关节置换术后关节的稳定性。最近的研究主要集中在脊柱-骨盆-髋关节侧位x线片所观察到的髋关节功能安全区。本研究的目的是评估lewinnek安全区和功能安全区之间的相关性，本研究测量数据是基于髋关节和骨盆在矢状面上的运动。
方法：应用计算机导航技术对320髋(291例患者)进行初次全髋关节置换术。其中296髋(92.5%)位于lewinnek安全区内，外倾角为40°±10°，前倾角为15°±10°。所有患者术前和术后均行站位和坐位脊柱骨盆侧位x线片检查。每例患者均测量联合矢状指数(CSI)，联合矢状面髋臼位置和股骨头位置，并用于评估功能安全区。对这些测量数据进行分析，以确定在lewinnek安全区内、外的患者是否在矢状面功能安全区。评价处于功能安全区外的影响髋关节稳定性的预测因素。
结果：在lewinnek安全区内的296例髋关节中，有254髋(85.8%)处于功能安全区内。42名患者在CSI的功能安全区之外，19例站立位CSI增加，23例坐姿csi减少，均被认为有脱位的危险。在功能安全区外的预测因素为股骨活动度增加(p<0.001，r=0.632)、脊盆活动度降低(p<0.001，r=0.455)和骨盆入射角(p<0.001，r=0.400)。
结论:在这项研究中，lewinnek安全区内14.2%的髋关节位于功能安全区之外，虽然这些髋关节有既往认为“正常”的臼杯角度。术前和术后不在功能安全区内的最准确预测指标是患者股骨的活动度，而不是矢状位髋臼杯的位置(即，髋臼杯的前倾)。
Functional Safe Zone Is Superior to the Lewinnek Safe Zone for Total Hip Arthroplasty: Why the Lewinnek Safe Zone Is Not Always Predictive of Stability
Background: The Lewinnek 'safe zone' is not always predictive of stability after total hip arthroplasty (THA). Recent studies have focused on functional hip motion as observed on lateral spine-pelvis-hip x-rays. The purpose of this study was to assess the correlation between the Lewinnek safe zone and the functional safe zone based on hip and pelvic motion in the sagittal plane.
Methods: Three hundred twenty hips (291 patients) underwent primary THA using computer navigation. Two hundred ninety-six of these hips (92.5%) were within the Lewinnek safe zone as determined by inclination of 40° ± 10° and anteversion of 15° ± 10°. All patients had preoperative and postoperative standing and sitting lateral spinopelvic x-rays. The combined sagittal index (CSI), a combination of sagittal acetabular and femoral position, was measured for each patient and used to assess the functional safe zone. Data analysis was performed to identify hips in the Lewinnek safe zone inside and outside the sagittal functional safe zone. Predictive factors for hips outside the functional safe zone were identified.
Results: Of the 296 hips within the Lewinnek safe zone, 254 (85.8%) were also in the functional safe zone. Forty-two patients were outside the functional safe zone based on CSI; 19 had an increased standing CSI and 23 had a decreased sitting CSI, all were considered at risk for dislocation. Predictive factors for falling outside the functional safe zone were increased femoral mobility (P < .001, r = 0.632), decreased spinopelvic mobility (P < .001, r = 0.455), and pelvic incidence (P < .001, r = 0.400).
Conclusion: In this study, 14.2% of hips within the Lewinnek safe zone were outside the functional safe zone, identifying a potential reason hips dislocate despite having 'normal' cup angles. The best predictor for falling outside the functional safe zone, both preoperatively and postoperatively, was femoral mobility, not the sagittal cup position (ie, cup anteinclination).
文献出处：Tezuka T, Heckmann ND, Bodner RJ, Dorr LD. Functional Safe Zone Is Superior to the Lewinnek Safe Zone for Total Hip Arthroplasty: Why the Lewinnek Safe Zone Is Not Always Predictive of Stability. J Arthroplasty. 2019 Jan;34(1):3-8. doi: 10.1016/j.arth.2018.10.034. Epub 2018 Nov 2. PMID: 30454867.
文献3
重新考虑全膝关节置换术中常规应用止血带的合理性
译者：张蔷
目的：许多术者在全膝关节置换术中常规应用止血带。止血带是环绕下肢的束带装置，减少流向下肢的血液。应用的同时，我们需要考虑它的安全性，是否会给病人带来收益或者伤害。本篇文章的目的就是确定全膝关节置换术中应用止血带的收益或损害。
方法：我们搜索了MEDLINE、EMBASE和Cochrane数据库中截止2020年3月26日的数据。入组了所有比较全膝关节置换应用止血带和不应用止血带的随机对照试验（RCT）。评价指标包括：疼痛、功能、严重不良事件（SAEs）、失血、假体稳定性、手术时间和住院时长。
结果：我们入组了41项RCT试验共2819个病例。止血带组的SAEs明显多于非止血带组（53/901 vs 26/898, 止血带组 vs 非止血带组）（风险概率比1.73，95%置信区间1.10-2.73）。止血带组术后第一天的平均疼痛评分是非止血带组的1.25倍（95%置信区间0.32-2.19）。组间失血量并无显著性差异（平均差异8.61ml；95%置信区间-83.76-100.97）。止血带组的平均住院时长比非止血带组长0.34天（95%置信区间0.03-0.64），平均手术时间短3.7分钟（95%-5.53-1.87）。
结论：全膝关节置换应用止血带与严重不良事件增多、疼痛加重和住院时间延长相关。应用止血带的唯一优势是手术时间缩短。这一结果很难支持全膝关节置换术中常规应用止血带。
Time to reconsider the routine use of tourniquets in total knee arthroplasty surgery
Aims: Many surgeons choose to perform total knee arthroplasty (TKA) surgery with the aid of a tourniquet. A tourniquet is a device that fits around the leg and restricts blood flow to the limb. There is a need to understand whether tourniquets are safe, and if they benefit, or harm, patients. The aim of this study was to determine the benefits and harms of tourniquet use in TKA surgery.
Methods: We searched MEDLINE, EMBASE, Cochrane Central Register of Controlled trials, and trial registries up to 26 March 2020. We included randomized controlled trials (RCTs), comparing TKA with a tourniquet versus without a tourniquet. Outcomes included: pain, function, serious adverse events (SAEs), blood loss, implant stability, duration of surgery, and length of hospital stay.
Results: We included 41 RCTs with 2,819 participants. SAEs were significantly more common in the tourniquet group (53/901 vs 26/898, tourniquet vs no tourniquet respectively) (risk ratio 1.73 (95% confidence interval (CI) 1.10 to 2.73). The mean pain score on the first postoperative day was 1.25 points higher (95% CI 0.32 to 2.19) in the tourniquet group. Overall blood loss did not differ between groups (mean difference 8.61 ml; 95% CI -83.76 to 100.97). The mean length of hospital stay was 0.34 days longer in the group that had surgery with a tourniquet (95% CI 0.03 to 0.64) and the mean duration of surgery was 3.7 minutes shorter (95% CI -5.53 to -1.87).
Conclusion: TKA with a tourniquet is associated with an increased risk of SAEs, pain, and a marginally longer hospital stay. The only finding in favour of tourniquet use was a shorter time in theatre. The results make it difficult to justify the routine use of a tourniquet in TKA surgery.
文献出处：Ahmed I, Chawla A, Underwood M, Price A, Metcalfe A, Hutchinson C, Warwick J, Seers K, Parsons H, Wall PDH. Time to reconsider the routine use of tourniquets in total knee arthroplasty surgery. Bone Joint J. 2021 Mar 8:1-10. doi: 10.1302/0301-620X.103B.BJJ-2020-1926.R1. Epub ahead of print. PMID: 33683139.
文献4
可溶性Pecam-1作为关节假体周围感染的生物标志物
译者：沈松坡
目前尚缺乏一种可靠的、具有足够敏感性和特异性的单一诊断指标来确诊关节假体周围感染(PJI)。免疫反应分子Pecam-1由特定病原体触发后，通过激活促炎症信号从t细胞表面脱落。因此我们推测可溶性Pecam-1 (sPecam-1)可以作为PJI的生物标志物。58例患者被前瞻性地纳入并被分配到一个各自的治疗组(分为三组，一组为尚未做手术的膝关节，一组是非感染性膝关节置换术后翻修，另一组感染性全膝关节置换术(TKA术后)翻修)。通过采集滑膜样本和ELISA检测，建立局部sPecam-1水平数据库。我们观察到感染性翻修手术(n = 22)中sPecam-1的数量明显高于无菌性TKA翻修手术(n = 20, p≤0.001)。此外，与初次置换的膝关节相比，在感染性翻修组和无菌性翻修组中发现了大量的sPecam-1 (n = 16, p≤0.001)。将其与金标准进行对比，显示出其对PJI检测的高预测能力。局部的sPecam-1水平与植入物的感染状态相关，因此具有很强的作为PJI的生物标志物的潜力。虽然足以证明sPecam-1在感染中的明确作用，但还需要进一步阐明分子自然功能的潜在机制。
Soluble Pecam-1 as a Biomarker in Periprosthetic Joint Infection
A reliable workup with regard to a single diagnostic marker indicating periprosthetic joint infection (PJI) with sufficient sensitivity and specificity is still missing. The immunologically reactive molecule Pecam-1 is shed from the T-cell surface upon activation via proinflammatory signaling, e.g., triggered by specific pathogens. We hypothesized that soluble Pecam-1 (sPecam-1) can hence function as a biomarker of PJI. Fifty-eight patients were prospectively enrolled and assigned to one of the respective treatment groups (native knees prior to surgery, aseptic, and septic total knee arthroplasty (TKA) revision surgeries). Via synovial sample acquisition and ELISA testing, a database on local sPecam-1 levels was established. We observed a significantly larger quantity of sPecam-1 in septic (n = 22) compared to aseptic TKA revision surgeries (n = 20, p ≤ 0.001). Furthermore, a significantly larger amount of sPecam-1 was found in septic and aseptic revisions compared to native joints (n = 16, p ≤ 0.001). Benchmarking it to the gold standard showed a high predictive power for the detection of PJI. Local sPecam-1 levels correlated to the infection status of the implant, and thus bear a strong potential to act as a biomarker of PJI. While a clear role of sPecam-1 in infection could be demonstrated, the underlying mechanism of the molecule’s natural function needs to be further unraveled.
文献出处：Fuchs M, Trampuz A, Kirschbaum S, Winkler T, Sass FA. Soluble Pecam-1 as a Biomarker in Periprosthetic Joint Infection. J Clin Med. 2021 Feb 5;10(4):612. doi: 10.3390/jcm10040612. PMID: 33562828; PMCID: PMC7914675.
文献5
阿司匹林预防全髋和全膝关节置换术后
静脉血栓的临床有效性和安全性：
关于RCT的系统综述和Meta分析
译者：张峻
研究重要性：全髋关节置换术（THR）和全膝关节置换术（TKR）的患者采取药物预防静脉血栓栓塞（VTE）。哪种抗凝药物最佳仍不确定。观察性数据提示阿司匹林能够有效预防VTE。
目的：评价阿司匹林预防全髋和全膝关节置换术后静脉血栓的有效性和安全性
数据来源：关于RCT的系统综述和Meta分析，不限语种，自数据库成立至2019年9月19日使用MEDLINE, Embase, Web of Science, Cochrane 图书馆, and bibliographic 搜索RCT。
基于计算机的搜索结合了与人群（如髋关节置换术、膝关节置换术、髋关节成形术和膝关节成形术）、药物干预（如阿司匹林、肝素、氯氧烷、达比加群、利伐沙班和华法林）和结果（如静脉血栓栓塞、深静脉血栓形成，肺栓塞和出血）相关的术语和关键词组合。
研究选择：本研究包括评价成人行全髋和全膝关节置换术后阿司匹林与其它抗凝剂预防静脉血栓的有效性和安全性对比的RCT。排除有安慰剂对照的RCT。搜索和研究选择是独立进行的。
数据提取与合成：本研究遵循PRISMA声明，使用Cochrane协作风险偏倚工具。数据由两人独立筛选和提取。特定研究的相对风险使用随机效应模型进行汇总。证据质量评估价采用建议分级评价、发展和评价(GRADE)的方法。
主要结果和测量指标：主要结果是术后VTE（无症状或有症状）。次要结果是与治疗相关的不良事件，包括出血。
结果：在437篇文章中，纳入了13个随机对照试验（6060名参与者；3466名女性（57.2%）；平均年龄63.0岁）。与其他抗凝剂相比，阿司匹林经THR和TKR治疗后VTE的RR为1.12（95%CI，0.78-1.62）。深静脉血栓形成（DVT）（RR，1.04；95%CI，0.72-1.51）和肺栓塞（PE）（RR，1.01；95%CI，0.68-1.48）的结果具有可比性。服用阿司匹林和其它抗凝剂的患者发生严重出血、伤口血肿和伤口感染等不良事件的风险在统计学上没有显著差异。当分别分析THRs和TKRs时，阿司匹林和其他抗凝剂之间发生VTE、DVT和PE的风险没有统计学上的显著差异。阿司匹林与低分子肝素（RR，0.76；95%CI，0.37-1.56）或利伐沙班（RR，1.52；95%CI，0.56-4.12）相比，VTE风险无统计学差异。证据的质量从低到高不等。
结论和相关性：在临床有效性和安全性方面，阿司匹林与其它用于THR和TKR术后VTE预防的抗凝剂在统计学上没有显著差异。未来的试验应侧重于阿司匹林与其他抗凝剂和成本效益的非劣效性分析。
Clinical Effectiveness and Safety of Aspirin for Venous Thromboembolism Prophylaxis After Total Hip and Knee Replacement: A Systematic Review and Meta-analysis of Randomized Clinical Trials
Importance: Patients undergoing total hip replacement (THR) and total knee replacement (TKR) receive venous thromboembolism (VTE) pharmacoprophylaxis. It is unclear which anticoagulant is preferable. Observational data suggest aspirin provides effective VTE prophylaxis.
Objective: To assess the effectiveness and safety of aspirin for VTE prophylaxis after THR and TKR.
Data sources: A systematic review and meta-analysis was performed of randomized clinical trials (RCTs), with no language restrictions, from inception to September 19, 2019, using MEDLINE, Embase, Web of Science, Cochrane Library, and bibliographic searches. The computer-based searches combined terms and combinations of keywords related to the population (eg, hip replacement, knee replacement, hip arthroplasty, and knee arthroplasty), drug intervention (eg, aspirin, heparin, clexane, dabigatran, rivaroxaban, and warfarin), and outcome (eg, venous thromboembolism, deep vein thrombosis, pulmonary embolism, and bleeding) in humans.
Study selection: This study included RCTs assessing the effectiveness and safety of aspirin for VTE prophylaxis compared with other anticoagulants in adults undergoing THR and TKR. The RCTs with a placebo control group were excluded. The searches and study selection were independently performed.
Data extraction and synthesis: This study followed PRISMA recommendations and used the Cochrane Collaboration's risk of bias tool. Data were screened and extracted independently by both reviewers. Study-specific relative risks (RRs) were aggregated using random-effects models. Quality of evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach.
Main outcomes and measures: The primary outcome was any postoperative VTE (asymptomatic or symptomatic). Secondary outcomes were adverse events associated with therapy, including bleeding.
Results: Of 437 identified articles, 13 RCTs were included (6060 participants; 3466 [57.2%] women; mean age, 63.0 years). The RR of VTE after THR and TKR was 1.12 (95% CI, 0.78-1.62) for aspirin compared with other anticoagulants. Comparable findings were observed for deep vein thrombosis (DVT) (RR, 1.04; 95% CI, 0.72-1.51) and pulmonary embolism (PE) (RR, 1.01; 95% CI, 0.68-1.48). The risk of adverse events, including major bleeding, wound hematoma, and wound infection, was not statistically significantly different in patients receiving aspirin vs other anticoagulants. When analyzing THRs and TKRs separately, there was no statistically significant difference in the risk of VTE, DVT, and PE between aspirin and other anticoagulants. Aspirin had a VTE risk not statistically significantly different from low-molecular-weight heparin (RR, 0.76; 95% CI, 0.37-1.56) or rivaroxaban (RR, 1.52; 95% CI, 0.56-4.12). The quality of the evidence ranged from low to high.
Conclusions and relevance: In terms of clinical effectiveness and safety profile, aspirin did not differ statistically significantly from other anticoagulants used for VTE prophylaxis after THR and TKR. Future trials should focus on noninferiority analysis of aspirin compared with alternative anticoagulants and cost-effectiveness.
文献出处：Matharu GS, Kunutsor SK, Judge A, Blom AW, Whitehouse MR. Clinical Effectiveness and Safety of Aspirin for Venous Thromboembolism Prophylaxis After Total Hip and Knee Replacement: A Systematic Review and Meta-analysis of Randomized Clinical Trials. JAMA Intern Med. 2020 Mar 1;180(3):376-384. doi: 10.1001/jamainternmed.2019.6108. PMID: 32011647; PMCID: PMC7042877.
第二部分：保髋相关文献
文献1
股骨头坏死围塌陷期：保髋最后的机会
译者：罗殿中
目的：提出一个新的概念：股骨头坏死围塌陷期，并回顾其诊断和治疗价值。
数据来源：在PubMed、考克兰电子图书馆、EmBase三个电子数据库搜索符合条件的研究，截止到2018年8月10日，搜索关键词“osteonecrosis”、“prognosis”和“treatment”。
文献选择：对不同时期股骨头坏死的临床症状、体征、影像学表现的评价均纳入研究，对多种保髋手术预后的评价也进行回顾。
结果：围塌陷期指股骨头坏死出现软骨下骨折到早期塌陷（<2mm）的连续时期，具有特殊的影像学特征，包括MRI显示骨髓水肿和关节积液、X线显示新月征、临床表现为突然加重的髋关节疼痛。越来越多的证据表明这些征像是软骨下骨折的继发表现。值得一提的是，针对软骨下骨折的辨别，CT比MRI提供更多的信息，对围塌陷期的分期更为敏感。围塌陷期提示疾病进展可能性很大，同时提示此时进行保髋手术可以取得满意的中长期治疗效果。实际上，如果股骨头塌陷超过2mm，可以考虑关节置换。
结论：围塌陷期具有明确的临床和影像特征，并为保髋手术治疗提供了较好的最后的机会。围塌陷期作为一个独特的分期，应该从股骨头坏死病程中区分出来，并为恰当的治疗措施提供依据。
图1. 股骨头坏死三柱理论与中日友好医院分型示意图。根据股骨头坏死受累部位，股骨头坏死可分为内侧型（M型）坏死累及内侧柱；中间型（C型）坏死累及中间柱；外侧型（L型）坏死累及外侧柱。L型又可分为：L1型外侧柱部分完好；L2型坏死范围超出外侧柱；L3型内中外三柱均受累及。ONFH:股骨头坏死。
表1. SARS病人股骨头坏死进展到围塌陷期自然病程；SARS: 严重急性呼吸窘迫综合征；ONFH:股骨头坏死。
Pericollapse Stage of Osteonecrosis of the Femoral Head: A Last Chance for Joint Preservation
Objective: To propose a new definition of the pericollapse stage of osteonecrosis of the femoral head (ONFH) and review its significance in disease diagnosis and treatment selection.
Data sources: A search for eligible studies was conducted in three electronic databases including PubMed, Cochrane Library, and Embase up to August 10, 2018, using the following keywords: 'osteonecrosis', 'prognosis', and 'treatment'.
Study selection: Investigations appraising the clinical signs, symptoms, and imaging manifestations in different stages of ONFH were included. Articles evaluating the prognosis of various joint-preserving procedures were also reviewed.
Results: The pericollapse stage refers to a continuous period in the development of ONFH from the occurrence of subchondral fracture to early collapse (<2 mm), possessing specific imaging features that mainly consist of bone marrow edema and joint effusion on magnetic resonance imaging (MRI), crescent signs on X-ray films, and clinical manifestations such as the sudden worsening of hip pain. Accumulating evidence has indicated that these findings may be secondary to the changes after subchondral fractures. Of note, computed tomography provides more information for identifying possible subchondral fractures than does MRI and serves as the most sensitive tool for grading the pericollapse lesion stage. The pericollapse stage may indicate a high possibility of progressive disease but also demonstrates satisfactory long- and medium-term outcomes for joint-preserving techniques. In fact, if the articular surface subsides more than 2 mm, total hip arthroplasty is preferable.
Conclusions: The pericollapse stage with distinct clinical and imaging characteristics provides a last good opportunity for the use of joint-preserving techniques. It is necessary to separate the pericollapse stage as an independent state in evaluating the natural progression of ONFH and selecting an appropriate treatment regimen.
文献出处：Zhang QY, Li ZR, Gao FQ, Sun W. Pericollapse Stage of Osteonecrosis of the Femoral Head: A Last Chance for Joint Preservation. Chin Med J (Engl). 2018 Nov 5;131(21):2589-2598. doi: 10.4103/0366-6999.244111. PMID: 30381593; PMCID: PMC6213842.
文献2
关节镜治疗临界髋关节发育不良失败原因的
多中心研究：注意Tönnis角
译者：程徽
背景：有证据表明髋关节镜是一种治疗成人轻度髋关节发育不良的有效方法。有许多放射学参数用于髋关节发育不良分类，但迄今为止很少有研究表明哪些参数对预测手术结果最重要。
目的：确定哪些术前影像学参数与关节镜治疗成人轻度髋关节发育不良预后不良相关。
研究设计：病例对照研究；证据等级3级。
方法：对2009年至2015年期间接受关节镜手术的轻度髋关节发育不良患者进行影像学分析。术前X线测量包括外侧中心边缘角、Tönnis角、颈干角、前中心边缘角、alpha角、股骨头突出指数和髋臼深度宽度比。失败的定义为病情改善（用改良Harris髋关节评分判断）未能利达到最小临床重要差异(MCID)或需要进行二次手术。X线摄影参数的分析采用等方差t检验。P值为0.05确定统计学意义。
图1 A. 髋臼深度宽度比；B. Tönnis角；C. alpha角；D. 前中心边缘角；E. 外侧中心边缘角；F. 股骨头突出指数；G. 颈干角。
结果：共纳入373髋，平均随访41个月(范围24-102个月)。其中，46髋(12%)需要二次手术，95髋(25%)改善不理想。总失败率为32.4%。没有某个或某些指标与改善不理想相关。较高的术前Tönnis角与二次手术相关，二次手术组平均Tönnis角为6.7°(95% CI, 5.3°-8.1°)，一次手术组平均Tönnis角为4.8°(95% CI, 4.4°-5.3°；P = .006)。Tönnis角每次增加1度，进行二次手术优势比为1.12 (95% CI, 1.0-1.2；P = 0.05)。在Tönnis角>10°的患者中，84%需要二次手术。
结论：Tönnis角度越高，手术风险越高。在Tönnis角每增加1度，二次手术的概率增加1.12。在角为Tönnis >10°的患者中，84%需要二次手术。
译者的话：目前虽然有一些研究显示髋关节镜对髋关节发育不良有效。但必须提醒大家，32.4%的总失败率对外科手术来说还是比较高的，需要谨慎对待。
A Multicenter Study of Radiographic Measures Predicting Failure of Arthroscopy in Borderline Hip Dysplasia: Beware of the Tönnis Angle
Background: Hip arthroscopy has been previously demonstrated to be an effective treatment for adult mild hip dysplasia. There are many radiographic parameters used to classify hip dysplasia, but to date few studies have demonstrated which parameters are of most importance for predicting surgical outcomes.
Purpose: To identify preoperative radiographic parameters that are associated with poor outcomes in the arthroscopic treatment of adult mild hip dysplasia.
Study design: Case-control study; Level of evidence, 3.
Methods: Radiographic analysis was performed in patients with mild hip dysplasia who underwent arthroscopic surgery between 2009 and 2015. Preoperative radiographic measurements included lateral center edge angle, Tönnis angle, neck shaft angle, anterior center edge angle, alpha angle, femoral head extrusion index, and acetabular depth-to-width ratio. Failure was defined as failure to achieve the minimal clinically important difference (MCID) utilizing the modified Harris Hip Score or as the need for secondary operation. The equal variance t test was used to analyze radiographic parameters. Statistical significance was determined using a P value of .05.
Results: A total of 373 hips underwent analysis with an average follow-up of 41 months (range, 24-102 months). Of these, 46 hips (12%) required secondary operation, and 95 (25%) failed to meet the MCID. The overall failure rate was 32.4%. There was no single measurement or combination thereof associated with failure to reach the MCID. Higher preoperative Tönnis angles were associated with secondary operation, with a mean of 6.7° (95% CI, 5.3°-8.1°) in the secondary operation group versus 4.8° (95% CI, 4.4°-5.3°) in the nonsecondary operation group (P = .006). The odds ratio was 1.12 (95% CI, 1.0-1.2; P = .05) per degree increase in Tönnis angle for secondary operation. In patients with a Tönnis angle >10°, 84% required secondary operation.
Conclusion: Higher Tönnis angles portend a higher risk for revision surgery. The probability of secondary operation was increased by a magnitude of 1.12 with each degree increase in the Tönnis angle. In patients with a Tönnis angle >10°, 84% required a secondary operation.
文献出处：Kade S McQuivey, Erwin Secretov, Benjamin G Domb, Bruce A Levy, Aaron J Krych, Matthew Neville, David E Hartigan. A Multicenter Study of Radiographic Measures Predicting Failure of Arthroscopy in Borderline Hip Dysplasia: Beware of the Tönnis Angle. Am J Sports Med. 2020 Jun;48(7):1608-1615. doi: 10.1177/0363546520914942. Epub 2020 Apr 28.
文献3
跑步过程中的伸髋肌力量、躯干姿势和伸膝肌的使用
译者：肖凯
背景：已有研究证实髋关节肌肉力量下降可导致各种膝关节损伤。
目的：确定跑步时伸髋肌力量与矢状面躯干姿势之间的关系，以及伸髋肌力量与髋膝伸肌工作之间的关系。
设计：描述性实验室研究。
地点：肌肉骨骼生物力学实验室。
患者或其他参与者：共有40名无症状的休闲跑步者纳入研究，其中20名男性（年龄= 27.1±7.0岁，身高= 1.74±0.69 m，体重= 71.1±8.2 kg）和20名女性（年龄= 26.2±5.8岁，身高= 1.65±0.74 m，体重= 60.6±6.6 kg）。
主要结果指标：使用测力计评估伸髋肌的最大等距肌力。当参与者以3.4 m / s的可控速度在地面上奔跑时，量化站立位的矢状面躯干姿势（相对于整个过程的垂直轴进行计算）以及伸髋伸膝肌的工作（能量吸收和能量产生的总和）。我们使用Pearson积差相关性来明确伸髋肌力量、平均矢状面躯干屈曲角度、伸髋肌工作和伸膝肌工作之间的关系。
结果：伸髋肌强度与躯干屈曲角（r = 0.55，P <.001）和伸髋肌工作（r = 0.46，P = .003）呈正相关。它与伸膝肌的工作成反比（r = -0.39，P = 0.01）。性别调整后，所有相关性均保持不变。
结论：我们的研究结果表明，跑步者髋关节伸肌无力会导致跑步过程中躯干姿势更直立。这种情况导致对膝关节伸直肌肉的过度依赖，可能导致膝关节过度使用性跑步受伤。
Hip-Extensor Strength, Trunk Posture, and Use of the Knee-Extensor Muscles During Running
Context: Diminished hip-muscle performance has been proposed to contribute to various knee injuries.
Objective: To determine the association between hip-extensor muscle strength and sagittal-plane trunk posture and the relationships among hip-extensor muscle strength and hip- and knee-extensor work during running.
Design: Descriptive laboratory study.
Setting: Musculoskeletal biomechanical laboratory.
Patients or other participants: A total of 40 asymptomatic recreational runners, 20 men (age = 27.1 ± 7.0 years, height = 1.74 ± 0.69 m, mass = 71.1 ± 8.2 kg) and 20 women (age = 26.2 ± 5.8 years, height = 1.65 ± 0.74 m, mass = 60.6 ± 6.6 kg), participated.
Main outcome measure(s): Maximum isometric strength of the hip extensors was assessed using a dynamometer. Sagittal-plane trunk posture (calculated relative to the global vertical axis) and hip- and knee-extensor work (sum of energy absorption and generation) during the stance phase of running were quantified while participants ran over ground at a controlled speed of 3.4 m/s. We used Pearson product moment correlations to examine the relationships among hip-extensor strength, mean sagittal-plane trunk-flexion angle, hip-extensor work, and knee-extensor work.
Results: Hip-extensor strength was correlated positively with trunk-flexion angle (r = 0.55, P < .001) and hip-extensor work (r = 0.46, P = .003). It was correlated inversely with knee-extensor work (r = -0.39, P = .01). All the correlations remained after adjusting for sex.
Conclusions: Our findings suggest that runners with hip-extensor weakness used a more upright trunk posture. This strategy led to an overreliance on the knee extensors and may contribute to overuse running injuries at the knee.
文献出处：Teng HL, Powers CM. Hip-Extensor Strength, Trunk Posture, and Use of the Knee-Extensor Muscles During Running. J Athl Train. 2016 Jul;51(7):519-24. doi: 10.4085/1062-6050-51.8.05. Epub 2016 Aug 11. PMID: 27513169; PMCID: PMC5317187.
文献4
婴幼儿DDH超声检查体位带来的差异：
冠状面屈曲位VS冠状面中立位
译者：任宁涛
背景：超声（US）是诊断和治疗婴儿发育性髋关节发育不良（DDH）的首选影像学方法，目前公认的在冠状面上区分正常和发育不良髋关节的指标包括股骨头覆盖率（FHC）、α角和β角。最近的数据表明，这些指标可能存在显著的操作者和扫描图间的变异性。然而很少有研究对患儿体位带来的潜在变异进行比较，特别是冠状面屈曲位和冠状面中立位。本研究旨在对不同DDH严重程度冠状面屈曲位和冠状面中立位上测量指数变化进行比较。
方法：采用回顾性研究，涵盖正常髋关节和不同程度DDH的髋关节，在诊断、早期治疗（2-3周）、中间时间（6-8周）和治疗完成方面，由同一个研究小组对冠状面屈曲位和中立位上US图像进行评估。对两个体位每个时间点上的FHC、α角和β角进行测量比较，并对所有指标进行观察者间和观察者内可靠性评估。
结果：共纳入168例髋关节（45例正常，45例Ortolani（ ），17例Barlow（ ），61例稳定性发育不良），在正常婴幼儿和所有DDH 三种严重程度时间点方面，冠状面屈曲位的FHC中位数显著低于冠状面中立位（平均降低8.4%；范围5.5%至10.9%；P<0.01）。在所有髋关节类型的冠状面屈曲位图像上α角也降低，但仅是在某些时间点上（平均降低3.3度；范围0至7.5度；P<0.01至0.35），β角较少的体位之间的变异，但可靠性较差。
结论：在DDH严重程度和治疗时间点方面，冠状面屈曲位和中立位的FHC和α角存在显著差异，屈曲位可能与Barlow征检查类似，提示髋关节微不稳定，所有髋关节FHC的显著和持续的下降证明了这一点。因此，在屈曲位测量的指数可能代表更严格的标准来定义正常髋关节。
图1 两种体位
Coronal Flexion Versus Coronal Neutral Sonographic Views in Infantile DDH: An Important Source of Variability
Background: Ultrasound (US) is the preferred imaging modality for the diagnosis and treatment of infantile developmental dysplasia of the hip (DDH). Currently accepted indices that distinguish normal from dysplastic hips in the coronal plane include percent femoral head coverage (FHC), α angle, and β angle. Recent data suggests that significant user and interscan variability may exist for these metrics. Less studied, however, is potential variability because of patient positioning, specifically coronal flexion versus coronal neutral views. The purpose of this study was to compare standard DDH indices between coronal US views with hips in flexion versus neutral positions, for hips of varying DDH severity.
Methods: This retrospective study included normal infants and those treated for different severities of DDH. Coronal flexion and coronal neutral US images from the same study were evaluated at diagnosis, early treatment, start of weaning, and treatment resolution. FHC, α, and β angles were measured on both views at each time point and compared. Inter-rater and intra-rater reliability assessments were performed for all metrics.
Results: Among the 168 hips in this study (45 normals, 45 Ortolani positive, 17 Barlow positive, and 61 stable dysplasia), median FHC was significantly lower in coronal flexion compared with coronal neutral for normals and all 3 severities of DDH at each time point (mean decrease 8.4%; range 5.5% to 10.9%; P<0.01). Alpha angle also decreased on coronal flexion views, observed for all hip types, but only at certain time points (mean decrease 3.3 degrees; range 0 to 7.5 degrees; P<0.01 to 0.35). β angles demonstrated less variability between views, but also had poor reliability.
Conclusions: Coronal flexion and coronal neutral views demonstrated significant differences in FHC and α angle across a spectrum of DDH severities and treatment time points. Flexion views may represent a 'baby Barlow' test, revealing subtle instability as evidenced by the significant and consistent decrease in FHC across all hips. Indices measured in flexion, therefore, may represent more stringent criteria for defining normal hips.
文献出处：Blake C Meza, Jie C Nguyen , Jacob L Jaremko , Wudbhav N Sankar .Coronal Flexion Versus Coronal Neutral Sonographic Views in Infantile DDH: An Important Source of Variability. J Pediatr Orthop . 2020 Jul;40(6):e440-e445.
文献5
髋臼周围截骨术后患者报告结果与股骨头覆盖率和
髋臼方向的相关性：单中心队列研究
译者：张利强
背景：更好地了解髋臼发育不良的三维基本模式将有助于更好地指导治疗和优化髋臼周围截骨术（PAO）后的临床结果。
目的：（1）探讨髋臼发育不良行PAO治疗前后股骨头覆盖率与患者报告的预后评分（PROM）之间的关系；（2）评估根据渥太华分类是否可以预测髋臼矫正的方向。
研究设计：队列研究；证据水平，3。
方法：回顾性分析单中心机构注册数据库前瞻性收集的PAO资料，分析至少2年的PROM评分。共有79髋（67名患者[56名女性]；平均手术年龄27.5岁[范围15.8-53.7岁]）符合纳入标准。根据渥太华分类，54髋（68.4%）有全髋关节发育不良，15髋（18.9%）有髋关节后方发育不良，10髋（12.7%）有髋关节前方发育不良。应用Hip2Norm软件分析股骨头三维覆盖情况。采用髋关节残疾和骨关节炎结局评分（HOOS）日常生活活动量表的最小临床重要差异（MCID）对PROMs改善的显著预测因子进行统计分析。
结果：平均随访3.1年（2.0-7.4年），所有功能结果评分均明显改善。术后股骨头总覆盖率＜75.7%，后方覆盖率＜45.2%，股骨头外移指数＞15.5%，均与HOOS日常生活活动量表未达到MCID有关。多变量分析显示PC是影响PAO治疗髋臼发育不良后功能结果的唯一最重要因素，优势比为6.0（95%CI，1.8-20.4；P=0.004）。单因素方差分析显示，根据渥太华分类（P<0.001），与X线测量的平均变化相比，前覆盖率、后覆盖率和股骨总覆盖率存在显著差异。
结论：我们的研究表明，术后股骨头覆盖率和髋臼方向是PROM的重要预测因素。根据不稳定平面将髋臼发育不良分为3组，可以更好地了解三维畸形，从而优化PAO的规划。
（A） 一位22岁女性患者的术前骨盆正位（AP）平片显示，右髋臼为全髋发育不良（根据渥太华分类为G级），图示外移指数，未覆盖股骨头（a）与总水平股骨头直径（a b）的比率为27%，术后降至8%（插图）。（B）髋臼周围截骨术后在骨盆平片上利用Hip2Norm手动标识，包括骶尾关节（上蓝十字）和耻骨联合上缘（下蓝十字），用于矢状面参照；泪滴的下缘（红十字），用于水平面参照；股骨头（粉红十字）和髋臼（绿十字）的中心；髋臼前缘（蓝线）和后缘（红线）的投影。利用前后视图（插图a）和上下视图（插图b）分析右髋。（C） 髋臼三维重建前后，在前后位上计算前覆盖率，后覆盖率，计算髋臼在上下方向（蓝色箭头）的总股骨覆盖率（Hip2Norm软件的插图显示了髋臼在上下方向的前（蓝线）和后（红线）的股骨头覆盖率）。髋臼硬化带由粗黑线表示。
（A） 前覆盖率（蓝色斑块）：髋臼前缘（实线）在前后方向覆盖的股骨头百分比。（B） 后覆盖率（红色斑块）：股骨头在后向前方向上被髋臼后缘（虚线）覆盖的百分比。（C） 股骨总覆盖率：髋臼在上下方向（蓝色箭头）覆盖股骨头的百分比，即上下覆盖率。（D） 外侧中心边缘角：骨盆纵轴与连接股骨头中心与髋臼外侧边缘的线（粗黑线）之间的角度。（E） 髋臼指数：骨盆水平轴与连接髋臼顶部硬化区最内侧和外侧点的线（粗黑线）之间的角度。（F） 外移指数：未覆盖股骨头（a）与总水平头直径（a b）的比值。（G）后壁征：髋臼后缘（虚线）向股骨头中心内侧突出（黑点）。交叉征：突出的前壁与后壁交叉。髋臼后倾指数：后倾的髋臼开口长度（a）与髋臼外侧开口全长（b）的比值。
Correlation of Patient-Reported Outcomes After Periacetabular Osteotomy With Femoral Head Coverage and Acetabular Orientation: A Single-Center Cohort Study
Background: Gaining a better understanding of the underlying pattern of acetabular dysplasia 3-dimensionally can help better guide treatment and optimize clinical outcomes after periacetabular osteotomy (PAO).
Purpose: (1) To examine the relationship between femoral head coverage before and after PAO for dysplasia and patient-reported outcome measure (PROM) scores and (2) to assess if the direction/orientation of correction of the acetabulum can be predicted based on the Ottawa classification.
Study Design: Cohort study; Level of evidence, 3.
Methods: A retrospective analysis of a prospectively collected database from a single-center institutional registry of PAO was conducted, and PROM scores at a minimum of 2 years were analyzed. A total of 79 hips (67 patients [56 female]; mean age at surgery, 27.5 years [range, 15.8-53.7 years]) were available for inclusion. According to the Ottawa classification, 54 hips (68.4%) had global deficiency, 15 hips (18.9%) had posterior deficiency, and 10 hips (12.7%) had anterior deficiency. Hip2Norm software was used to analyze the 3-dimensional coverage of the femoral head. Statistical analysis was conducted to look at significant predictors of improvements in PROMs using the minimal clinically important difference (MCID) for the Hip disability and Osteoarthritis Outcome Score (HOOS) Activities of Daily Living subscale.
Results: At a mean follow-up of 3.1 years (range, 2.0-7.4 years), all functional outcome scores improved significantly. A postoperative total femoral coverage < 75.7%, posterior coverage (PC) < 45.2%, and femoral head extrusion index > 15.5% were all associated with not reaching the MCID for the HOOS Activities of Daily Living subscale. Multivariate analysis showed that PC was the single most important significant modifier influencing functional outcomes after PAO for the treatment of acetabular dysplasia, with an odds ratio of 6.0 (95% CI, 1.8-20.4; P = .004). One-way analysis of variance showed a significant difference comparing the mean change in radiographic measurements, that is, anterior coverage, PC, and total femoral coverage, per the Ottawa classification (P <.001).
Conclusion: Our study demonstrated that postoperative femoral head coverage and acetabular orientation were significant predictors of PROM scores. Classifying acetabular dysplasia into 3 groups based on the plane of instability could optimize the planning of PAO by giving a better understanding of the 3-dimensional deformity.
文献出处：Ibrahim MM, Smit K, Poitras S, Grammatopoulos G, Beaulé PE. Correlation of Patient-Reported Outcomes After Periacetabular Osteotomy With Femoral Head Coverage and Acetabular Orientation: A Single-Center Cohort Study. Am J Sports Med. 2021 Mar 4:363546521992108. doi: 10.1177/0363546521992108. Epub ahead of print. PMID: 33661717.
文献6
关节镜与开放性股骨髋臼撞击症的治疗：
中长期结果的系统评价
译者：陶可（北京大学人民医院骨关节科）
背景：症状性股骨髋臼撞击症（FAI）的外科治疗旨在改善症状并可能延迟髋关节骨关节炎的发生，同时，防止进展为终末期髋关节骨关节炎以及可能的全髋关节置换术（THA）。髋关节镜检查和开放性髋关节外科脱位是用于治疗FAI最常见的两种手术方法。
目的：进行一项对照性系统评价，以确定在最低限度的中期随访中，髋关节镜和开放性髋关节外科脱位治疗FAI的临床结果和进展为THA之间，是否存在显著差异。
研究设计：系统评价和荟萃分析。
方法：使用PubMed界面对MEDLINE数据库进行了系统评价。纳入研究的最低平均随访时间定为36个月。纳入的研究是以英文发表的，具体为在关节镜或开放性FAI治疗后，评估结果在最少平均中期时间框架内。统计方法采用了独立t检验、Kaplan-Meier生存分析和加权平均合并队列分析。
结果：共有16项研究符合纳入标准。有9项开放性髋关节外科脱位研究和7项髋关节镜检查研究。开放研究包括600例髋，平均随访57.6个月（4.8年；范围6-144个月）。关节镜检查包括1484髋，平均随访50.8个月（4.2年；范围12-97个月）。以THA为终点，开放手术的总生存率为93％，关节镜手术的总生存率为90.5％（P = .06）。两种治疗后，高龄和先前存在的软骨损伤都是发展为THA的危险因素。两种手术治疗FAI在特殊疾病结果之间的直接比较参数受到结果指标异质性的限制。但是，两种治疗方法在各自的评分系统中均显示出良好的效果。值得注意的是， SF-12简易生活质量问卷显示髋关节镜检查与较高的一般健康相关生活质量评分（HRQoL）相关（P <0.001）。
结论：在中期随访中，无论是髋关节镜检查还是开放性髋关节外科脱位，采用特定的髋关节随访结果指标，均显示出极佳的且等同的髋关节存活率，证明了两组之间的等效性。但是，与一般治疗相比，髋关节镜检查在一般HRQoL方面显示出更好的结果。仍然需要对FAI的自然病史进行更深入的探索，以评估FAI患者的长期疗效。
开放性髋关节外科脱位和髋关节镜治疗股骨髋臼撞击症的Kaplan-Meier生存分析，以进展为全髋关节置换术为终点。
Arthroscopic Versus Open Treatment of Femoroacetabular Impingement: A Systematic Review of Medium- to Long-Term Outcomes
Background: Surgical treatment of symptomatic femoroacetabular impingement (FAI) aims to improve symptoms and potentially delay initiation of hip osteoarthritis and prevent progression to end-stage hip osteoarthritis and possible total hip arthroplasty (THA). Hip arthroscopy and open surgical hip dislocations are the 2 most common surgical approaches used for this condition.
Purpose: To perform a comparative systematic review to determine whether there is a significant difference in clinical outcomes and progression to THA between hip arthroscopy and open surgical hip dislocation treatment for FAI at minimum medium-term follow-up.
Study design: Systematic review and meta-analysis.
Methods: A systematic review of the MEDLINE database by use of the PubMed interface was performed. Minimum mean follow-up for included studies was set at 36 months. English-language studies with a minimum mean medium-term time frame evaluating outcome after arthroscopic or open treatment of FAI were included. Independent t tests, Kaplan-Meier survival analysis, and weighted mean pooled cohort statistics were performed.
Results: A total of 16 studies met inclusion criteria. There were 9 open surgical hip dislocation studies and 7 hip arthroscopy studies. Open studies included 600 hips at a mean follow-up of 57.6 months (4.8 years; range, 6-144 months). Arthroscopic studies included 1484 hips at a mean follow-up of 50.8 months (4.2 years; range, 12-97 months). With THA as an outcome endpoint, there was an overall survival rate of 93% for open and 90.5% for arthroscopic procedures (P = .06). Advanced age and preexisting chondral injury were risk factors for progression to THA after both treatments. Direct comparison among disease-specific outcome instruments between the 2 procedures was limited by outcome measure heterogeneity; however, both treatments demonstrated good outcomes in their respective scoring systems. Notably, hip arthroscopy was associated with a higher general health-related quality of life (HRQoL) score on the 12-Item Short-Form Survey physical component score (P < .001).
Conclusion: Both hip arthroscopy and open surgical hip dislocation showed excellent and equivalent hip survival rates at medium-term follow-up with hip-specific outcome measures, demonstrating equivalence between groups. However, hip arthroscopy was shown to have superior results regarding general HRQoL in comparison to open treatment. An increased understanding of the natural history of FAI remains warranted, with further studies needed to assess long-term outcomes for patients with FAI.
文献出处：Benedict U Nwachukwu, Brian J Rebolledo, Frank McCormick, Samuel Rosas, Joshua D Harris, Bryan T Kelly. Arthroscopic Versus Open Treatment of Femoroacetabular Impingement: A Systematic Review of Medium- to Long-Term Outcomes. Am J Sports Med. 2016 Apr;44(4):1062-8.