Distal Humeral Fractures in Adults成人中的肱骨遠端骨折Aaron Nauth, Michael D. McKee, Bill Ristevski, Jeremy Hall and Emil H. SchemitschJ Bone Joint Surg Am. 2011;93:686-700.Distal humeral fractures in adults are relatively uncommon injuries that require operative intervention in the majority of cases.Dual plate fixation, with placement of a separate strong plate on each column and orientation of the plates either at 90_ or 180_ to each other, is indicated for all adult fractures involving both columns of the distal part of the humerus.Acute total elbow arthroplasty is the preferred treatment for elderly patients with a displaced, comminuted, intraarticular distal humeral fracture that is not amenable to stable internal fixation.Displaced coronal shear fractures of the distal humeral articular surface require operative fixation, most typically via a lateral approach. 肱骨遠端骨折在成人損傷中并不常見，大部分病例需要手術干預。雙鋼板固定適用于所有肱骨遠端涉及雙柱的成人骨折，這一技術要求在每個柱上各置入一枚堅強的鋼板，兩枚鋼板之間的方向為90度或180度。在難復性移位粉碎的肱骨遠端骨折中，內固定不能使骨折獲得穩定時，對于老年患者可給予急癥全肘關節置換治療。肱骨遠端關節面的冠狀面剪力移位骨折需要內固定手術治療，多經外側入路實施手術。 Distal humeral fractures in adults are complex and technically demanding injuries to manage. Operative intervention is indicated in most cases and is often complicated by difficult exposure, osteoporotic bone, and comminution in the metaphyseal and/or articular region. There is controversy regarding a number of issues pertaining to the management of distal humeral fractures, including the correct operative approach, fixation strategies, the role of total elbow arthroplasty, management of the ulnar nerve, and indications for prophylaxis against heterotopic ossification. This article provides an overview of these issues and others by reviewing the available evidence in the literature on distal humeral fractures and providing graded recommendations. 成人中的肱骨遠端骨折的處理較為復雜，技術要求較高。大部分病例適于手術治療，并發癥的發生常由于手術暴露困難，骨質疏松以及干骺端或/和關節面粉碎等因素所致。肱骨遠端骨折處理中的相關問題包括正確的選擇手術入路，固定策略，全肘關節置換的意義，尺神經的處理以及實施異位骨化預防措施的指證等。本文通過回顧肱骨遠端骨折的相關文獻，對上述問題進行分析總結并提出分級治療意見。Epidemiology流行病學Distal humeral fractures have an estimated incidence in adults of 5.7 per 100,000 persons per year1. These injuries occur in a bimodal distribution, with an early peak in young males, twelve to nineteen years of age, as a result of high-energy trauma, and a second peak in elderly women, with osteoporotic bone, as a result of falls. In a recent study based on the Finnish National Health Registry, the authors reported a dramatic increase in the annual incidence of distal humeral fractures (from twelve per 100,000 to thirty-four per 100,000) in women sixty years of age or older during the period of 1970 to 19982. The actual number of lowenergy distal humeral fractures in this patient population increased even more dramatically, from forty-two fractures to 224 fractures, over the same time period. These dramatic increases were not sustained over the period from 1998 to 2007, during which the incidence and number of distal humeral fractures stabilized.These data indicate that, although fractures of the distal part of the humerus are rare in adults, there has been a substantial increase in their number and incidence. The dramatic increases reported in elderly women with potentially osteoporotic bone is of particular note, suggesting that fixation strategies for osteoporotic bone, possibly joint replacement techniques, as well as the management of osteoporosis itself will play important roles in the future management of these injuries. 肱骨遠端骨折在成人中可估量的發病率為5.7/100,000/年【1】。這種損傷呈雙峰分布，第一個高峰出現在12-19歲的青年男性患者中，為高能量損傷所致；第二個高峰存在骨質疏松的老年女性，多為跌落傷所致。最近，在一項基于芬蘭國民健康登記系統的研究報告中【2】，作者稱1970年至1998年間60歲及其以上年齡的婦女其肱骨遠端骨折的年發病率呈顯著增加趨勢（從12/100000增加到34/100000）。在這一病例人群中急性低能量性肱骨遠端骨折的增加更為顯著并超過同期水平，從42例增加到224例。這種顯著增加趨勢并不包括19982007年間的數據，在這一時期肱骨遠端骨折的發病率及病人數量較為穩定。這些數據結果表明，盡管肱骨遠端骨折在成人中較為少見，但其發病率及病人數量卻不斷增加，這在存在潛在骨質疏松的老年婦女人群中尤為突出，這表明，除了骨質疏松本身的處理，骨質疏松骨折的固定策略以及關節置換技術也在這類損傷未來的治療中扮演重要角色。Classification骨折分類Distal humeral fractures involve the supracondylar region of the humerus and/or the articular surface of the distal part of the humerus. They are most commonly classified according to the Orthopaedic Trauma Association/Arbeitsgemeinschaft fur Osteosynthesefragen (OTA/AO) classification system (Fig. 1). In this classification system, A designates an extra-articular fracture, B designates a partial articular fracture, and C indicates an intra-articular fracture in which the articular surface is completely dissociated fromthe shaft of the humerus. These three types are subdivided with use of the numbers 1, 2, and 3 to indicate increasing degrees of comminution or to further define the location of the fracture. On the basis of epidemiological data from the United Kingdom, the distribution of these fractures has been reported to be 38.7% type A, 24.1% type B, and 37.2% type C1. 肱骨遠端骨折包括肱骨髁上骨折和肱骨髁間骨折。應用最為普遍的分類方法為OTA/AO分類系統（圖1）。在這一分類系統中，A型為關節外骨折，B型為關節內部分骨折，C型為關節內完全骨折，并伴有干骺端分離。這三種類型可進一步為三個亞型，分別以1、2、3表示骨折粉碎的程度，并可根據骨折的具體位置再做進一步細分?；谟牧餍胁W調查數據，三種類型的分布情況為A型占38.7%，B型占24.1%，C型占37.2%。Clinical Assessment and Radiography臨床及放射性評估The clinical evaluation of a patient with a distal humeral fracture should include careful assessment of the ipsilateral shoulder and wrist, examination of the skin for open wounds, and a detailed neurovascular examination. A patient with an open distal humeral fracture most commonly has a posterior wound proximal to the elbow joint that was created by protrusion of the humeral shaft through the tricepsmuscle and posterior skin3.Neurological assessment should include examination of the median, radial, and ulnar nerves. The prevalence of preoperative ulnar nerve symptoms in patients with a type-C fracture of the distal part of the humerus has been reported to be 24.8%4. 肱骨遠端骨折患者的臨床評估應包括同側肩、腕關節的細致查體，開放傷口皮膚的檢查以及具體的神經血管檢查。開放性肱骨遠端骨折患者由于肱骨干骨折端經肱三頭肌及后側皮膚穿出，因此傷口多出現在背側近肘關節處【3】。據報道【4】，在肱骨遠端C型骨折患者中其手術前尺神經癥狀的發生率達24.8%。Following clinical assessment, anteroposterior and lateral radiographs of the distal part of the humerus should be obtained (Fig. 2). In the setting of articular comminution, the use of computed tomography (CT) scanning with three-dimensional reconstructions can be helpful for classification and preoperative planning. Doornberg et al. compared the use of three dimensional CT reconstructions with the use of two-dimensional CT and radiographs for the classification of distal humeral fractures and treatment decision-making (Level-III evidence)5. The authors reported increased interobserver and intraobserver reliability for fracture classification as well as increased intraobserver reliability for treatment decisions with the use of three-dimensional CT. There have been several reports of Level-IV case series in which CT was used, primarily for the evaluation of coronal shear-type fractures of the distal part of the humerus (type B3)6-9在進行臨床評估之后，應進行肱骨遠端正側位X線片檢查（圖2）。對于關節內粉碎骨折，CT三維重建有助于骨折的分型和制定術前計劃。Doornberg等【5】比較了三維CT重建與二維CT加X線片在肱骨遠端骨折分型和制定治療測量的作用（循證醫學級別，III級）。作者報道稱，應用CT三維重建技術在骨折分型中可增加觀察者間和觀察者內部的可靠性，并可在治療決策上增加觀察者內部的可靠性。另外，還有多項研究報道了肱骨遠端冠狀面剪力骨折（B3型）的原始評估中CT應用的意義，其研究的循證醫學級別為IV級病例系列水平【6-9】。A Grade-C recommendation can be made for the selective use of CT scanning of fractures of the distal part of the humerus that involve the articular surface, particularly in the setting of articular comminution (Table I). A-C級推薦意見是基于肱骨遠端關節內骨折的CT掃描而制定地，特別適用于關節內粉碎骨折（表1）。Nonoperative Treatment非手術治療The outcomes of modern operative fixation of distal humeral fractures are such that operative intervention is indicated in most cases. Nonoperative management is reserved for completely undisplaced fractures, patients who are unable to tolerate anesthesia, and those with advanced dementia. This widely held view is supported by the available evidence, which suggests that operative management of distal humeral fractures is favored over nonoperative management with regard to several outcomes. Two Level-III studies, including one that was based exclusively on patients aged seventy-five years or older, compared functional outcomes between operatively and nonoperatively treated patients (n = 70)10,11. We performed a pooled analysis of those two studies, which demonstrated that patients treated nonoperatively are almost three times more likely to have an unacceptable result (RR relative risk = 2.8, 95% CI confidence interval = 1.78 to 4.4). Another retrospective study, by Robinson et al., compared the results in 273 operatively treated patients with those in forty-seven nonoperatively treated patients (Level-III evidence)1. The authors reported that nonoperatively treated patients were almost six times more likely to have a nonunion (RR = 5.8, 95% CI = 2.3 to 14.7) and four times more likely to have delayed union (RR = 4.4, 95% CI = 1.6 to 12.0). Numerous, recent Level-IV studies on modern techniques of fixation for distal humeral fractures have demonstrated high rates of satisfactory outcomes (47% to 93%), with acceptable rates of complications (19% to 53%)12-24. Overall, a Grade-B recommendation can be made for the operative management of all displaced fractures of the distal part of the humerus in patients able to tolerate anesthesia. In patients for whom anesthesia is deemed to pose too high a risk, conservative treatment with early mobilization is appropriate25. This typically involves immobilization of the elbow in 60_ of flexion for two to three weeks, followed by gentle range-of-motion exercises. 目前的肱骨遠端骨折手術固定效果表明大部分病例適于手術干預。非手術保守治療只適用于完全無移位骨折，不能耐受麻醉以及進展性老年癡呆癥的患者。詢證醫學結果表明，目前普通接受的觀點是肱骨遠端骨折的手術治療在多項臨床效果方面均優于非手術治療。兩項基于75歲及其以上年齡組循證醫學級III級的研究對手術與非手術治療的功能效果進行了比較(n = 70)【10,11】。我們對這兩項研究進行了會聚分析，結果表明非手術治療的患者不滿意率(RR 相關風險 = 2.8, 95% CI 可信區間 = 1.78 -4.4)較手術治療組至少高出3倍。在另一項回顧研究中，Robinson等【1】將273例手術患者與47例非手術治療患者進行了臨床效果的比較（循證醫學級別，III級）。其研究結果表明，在不愈合率方面，非手術治療患者為手術治療患者的大約6倍(RR = 5.8, 95% CI = 2.3 -14.7)，延遲愈合方面也達大約4倍(RR = 4.4, 95% CI = 1.6 - 12.0)。最近多項詢證醫學IV級的研究表明，肱骨骨折的現代固定技術滿意率高(47%- 93%)，并發癥的發生率(19%- 53%)也是可以接受地【12-24】。總體來講，對于能夠耐受麻醉的肱骨遠端移位骨折患者手術治療制定的推薦意見為B級。存在麻醉高風險的患者適于可早期活動的保守治療【25】。其一般措施包括屈肘制動60度3周，隨后逐步增加活動訓練的范圍。Operative Approach手術治療Numerous operative approaches for the management of distal humeral fractures have been described. With the exception of approaches described for the fixation of coronal shear fractures (discussed later in this text), these all employ a posterior skin incision with various strategies of working through or around the triceps muscle. Described approaches include the paratricipital (Alonso-Llames)26,27, triceps-reflecting (Bryan-Morrey)28, triceps reflecting anconeus pedicle (TRAP)29, triceps-splitting30,31, and olecranon osteotomy techniques32,33 (Fig. 3). There is controversy regarding the optimal approach for the fixation of distal humeral fractures. Irrespective of the approach used, the ulnar nerve must always be isolated, mobilized, and protected throughout the procedure. The nerve is identified proximal to the elbow in the medial intermuscular septum and can be secured with a Penrose drain. The cubital tunnel, proximal fascia of the flexor carpi ulnaris, and articular branch of the ulnar nerve are released, thereby mobilizing the nerve to the level of the first motor branch to the flexor carpi ulnaris (Fig. 4).While there is general agreement about isolation and mobilization of the ulnar nerve, what to do with the nerve at the conclusion of the procedure is a subject of some debate and will be discussed later. 肱骨遠端骨折可通過多種方式實施手術治療。除了冠狀面剪力骨折的手術固定方式有所不同外（將在本文的后半部分討論），其他所有手術方式均后側做皮膚切口，圍繞肱三頭肌實施不同的手術策略。具體手術入路（圖3）包括肱三頭肌兩側入路（Alonso-Llames入路），肱三頭肌翻轉入路（Bryan-Morrey入路）【28】，肱三頭肌翻轉-肘肌瓣入路(TRAP入路)【29】，肱三頭肌劈開入路【30,31】以及尺骨鷹嘴截骨入路【32,33】。對于肱骨遠端骨折的最佳入路選擇目前尚有爭議。無論何種手術方式，手術操作中均應游離、移動及保護尺神經。于肘關節近側內側肌間隔找到尺神經，可應用一Penrose引流管對其進行牽開保護。對肘管、尺側腕屈肌近側筋膜以及尺神經關節支進行松解，應將尺神經游離至尺側腕屈肌的第一運動支水平（圖4）。在尺神經的游離移動這一點上，各方的觀點趨于一致，主要爭論的焦點是尺神經的最后處理問題，這將稍后做進一步討論。The paratricipital approach avoids violation of the extensor mechanism of the elbow by utilizing medial and lateral windows on either side of the triceps, making it the favored approach for extra-articular fractures (Fig. 5). The major disadvantage of this approach is limited visualization of the articular surface, although visualization is generally adequate for extra-articular fractures and type-C1 and C2 intra-articular fractures26,27. In addition, this approach can be converted to an olecranon osteotomy approach for increased articular exposure and facilitates conversion to a total elbow arthroplasty. Satisfactory functional outcomes have been reported with the use of this approach for type-A and type-C1 and C2 fractures (Level-IV evidence)26,27, although we are not aware of any studies comparing this approach with others for distal humeral fractures. Similarly, case series of the triceps-reflecting28 and TRAP29 approaches have been reported (Level-IV evidence), but there is no comparative evidence in the literature on distal humeral fractures. 肱三頭肌兩側入路通過在在肱三頭肌的兩側開窗可避免肘關節伸肌裝置的損害，這有更有利于關節外骨折的顯露（圖5）。盡管這一入路一般情況下能足夠的顯露關節外骨折及C1，C2型關節內骨折，但對關節面的顯露比較局限，這是它的主要缺陷【26,27】。另外，為了實現關節更好的顯露，這一入路可中轉為鷹嘴截骨入路，也可方便的中轉為全肘關節置換術。對于A型，C1，C2型骨折其應用的功能效果滿意【26,27】（詢證醫學級別，IV級）。盡管筆者未見這一入路與其他入路用于肱骨遠端骨折的比較研究。與之相類似，一些病例研究對肱三頭肌翻轉入路【28】及TRAP入路【29】進行報道（詢證醫學級別，IV級），但對于肱骨遠端的入路選擇，文獻中無對照研究的證據。The triceps-splitting approach involves a midline incision in the triceps fascia with sharp reflection of the triceps insertion off the olecranon, leaving the triceps tendon in continuity with the extensor/flexor fascia (Fig. 6)30. The proximal 1 cm of the olecranon tip is resected to improve visualization of the articular surface. At the conclusion of the procedure, the triceps tendon is repaired to the olecranon with use of transosseous, nonresorbable sutures.The olecranon osteotomy approach uses an apex distal, chevron-type osteotomy of the olecranon located 2.5 to 3 cm from the tip of the olecranon, oriented to exit in the so-called bare area of the trochlear groove (Fig. 7). The osteotomy is begun with an oscillating saw and completed with an osteotome. At the conclusion of the procedure, the osteotomy site is fixed with a tension band construct, an intramedullary screw, or a plate. 肱三頭肌劈開入路通過在肱三頭肌筋膜中間切開并將肱三頭肌的尺骨鷹嘴附著點翻轉，這可保留肱三頭肌腱屈/伸筋膜的連續性(圖6)【30】。近尺骨鷹嘴1cm處理切斷肱三頭肌肌腱以實現關節面的更好顯露。手術最后經骨應用非可吸收縫線重新將肱三頭肌腱固定與尺骨鷹嘴。尺骨鷹嘴截骨入路是從鷹嘴尖端到頂點遠端2.5 - 3 cm做鷹嘴的V字形截骨，從滑車溝的裸區穿出（圖7）。開始時應用擺鋸，之后應用骨鑿完成截骨。最后，截骨部位通過張力帶裝置，髓內螺釘或鋼板進行固定。Anatomic studies have demonstrated that the olecranon osteotomy provides superior visualization of the articular surface34. However, retrospective studies comparing the triceps-splitting and olecranon osteotomy approaches have not shown any significant differences in terms of functional outcomes (Level- III evidence)31,35,36. A retrospective comparison of the two approaches, by McKee et al., showed equivalent outcomes with regard to the Disabilities of the Arm, Shoulder and Hand (DASH) and Short Form-36 (SF-36) scores as well as objective muscle strength testing (n = 25 patients)31. However, the authors reported that three of eleven patients had a reoperation for removal of the olecranon implant in the osteotomy group (Level-III evidence). Other, Level-IV series of patients treated with olecranon osteotomy have had rates of implant removal ranging from 6% to 30% and rates of nonunion of the olecranon osteotomy site of 0% to 9%32,33,37,38. The triceps-splitting and olecranon osteotomy approaches for the treatment of open distal humeral fractures have also been compared retrospectively 3. In that study, of twenty-six patients, the triceps-splitting group had significantly better functional outcomes on the basis of the DASH (p = 0.05) and Mayo Elbow Performance Scores (MEPS) (p = 0.05) as well as a trend toward an improved range of motion (Level-III evidence). The authors hypothesized that this effect was due to the fact that open fractures typically were associated with a large tear in the triceps muscle and this tear was easily incorporated into the triceps-splitting approach. This seemed to offer an advantage over sectioning of the extensor mechanism at an adjacent site with an olecranon osteotomy. This study also provided Level-IV evidence that acute plate fixation of open distal humeral fractures was safe and reliable after adequate irrigation and debridement, with only one deep infection developing in the series.解剖學研究表明，鷹嘴截骨入路對關節面的顯露視野更佳【34】。然而，多項回顧性對照研究顯示肱三頭肌劈開入路與鷹嘴截骨入路在功能效果方面無顯著差異（循證醫學級別，III級）【31,35,36】。在一項對兩種入路的回顧性對照研究中，McKee等指出無論是主觀肌肉力量測試還是在臂-肩-手殘障功能評分(DASH)，SF-36評分等方面，二者得出的結果相同(n = 25例)【31】。但作者同時指出，鷹嘴截骨入路組的11例患者中有3例實施了鷹嘴部內固定物的取出手術（循證醫學級別，III級）。其它一些循證醫學級別IV級的病例研究顯示，鷹嘴截骨入路手術的內固定取出率為6% - 30%，鷹嘴截骨處的不愈合率為0%- 9%【32,33,37,38】。一項回顧性研究還比較了肱三頭肌劈開入路與鷹嘴截骨入路用于開放性肱骨遠端骨折的治療情況【3】。該研究顯示在DASH (p = 0.05)，Mayo肘關節功能評分(MEPS) (p = 0.05)以及關節活動度改善情況等方面，肱三頭肌劈開入路組（26例患者）的功能效果更佳（循證醫學級別，III級）。作者推測出現這一結果的原因是由于開放骨折往往存在肱三頭肌的廣泛撕裂，肌肉的撕裂對于實施肱三頭肌劈裂入路更為有利，這似乎較鷹嘴截骨臨近部位的伸肌裝置切開更具優勢。該研究中只有1例患者出現深部感染，這表明在經過充分的清創、沖洗之后，開放性肱骨遠端骨折的急癥鋼板固定是安全可靠地，其循證醫學級別為IV級水平。On the basis of the available evidence, a Grade-C recommendation can be made for the use of the paratricipital approach for extra-articular or simple intra-articular fractures. There is fair evidence to suggest that the use of a tricepssplitting approach leads to functional outcomes equivalent to those provided by an olecranon osteotomy while potentially avoiding the complications associated with the olecranon osteotomy, rendering this a Grade-B recommendation. In addition, there is fair evidence to suggest that the use of a tricepssplitting approach leads to improved functional outcomes compared with those following the use of an olecranon osteotomy for the treatment of open distal humeral fractures, rendering this a Grade-B recommendation in that setting. 基于詢證醫學證據，對于關節外骨折或簡單的關節內骨折推薦應用肱三頭肌雙側入路治療，其推薦意見等級為C級。應用肱三頭肌劈開入路獲得的功能效果與鷹嘴截骨入路相同，但卻可能避免出現鷹嘴截骨入路相關并發癥，這些觀點均有充分的證據支持。另外，也有充分的證據表明，對于肱骨遠端的開放性骨折，肱三頭肌劈開入路在功能效果的改善方面較之鷹嘴截骨入路更佳，其推薦意見級別為B級。Plate Fixation鋼板固定S