The stabilizing effect of various implants on the torn acromioclavicular joint

Summary A biomechanical in vitro test was performed to determine the stabilizing effect of various implants for the surgical treatment of the torn acromioclavicular joint. In a specially designed testing device, plastic and cadaver specimens of the shoulder girdle were stressed in various ways. Different dislocations between the acromion and the clavicle and between the clavicle and the coracoid were determined, as well as the stiffness of the implants. A convenient stabilizing effect combined with less rigid fixation to secure the newly treated AC joint was provided by K-wire fixation with cerclage. Interfering shear and bending stresses could be avoided with this method, while the other implants showed various disadvantages. From a biomechanical point of view, a carbon-fiber ligament replacement provides sufficient stability in cases of chronic acromioclavicular separation.

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Zusammenfassung Die stabilisierende Wirkung verschiedener bei der Behandlung der Schultereckgelenkssprengung Verwendung findender Implantate wurde in einem biomechanischen Test in vitro untersucht. In einer speziellen Testvorrichtung wurden Kunststoffmodelle and Leichenpräparate auf verschiedene Weise beansprucht. Neben der Höhe der acromioclavicularen Gelenksstufe wurden die coracoclaviculare Abstandszunahme wie such die Implantatssteifigkeit bestimmt. Ein guter Stabilisationseffekt, verbunden mit einer zufriedenstellenden, weniger rigiden Fixation des AC-Gelenkes zum Schutz des frisch rekonstruierten Kapselbandapparates, wurde für die Spickdrahttransfixation mit kombinierter Cerclage ermittelt. Die auftretenden Scher- and Biegekräfte können mit dieser Methode neutralisiert werden, wdhrend die anderen Verfahren zum Teil gravierende Nachteile aufweisen. In Fallen chronischer AC-Gelenk-Instabilität kann mit einem Kohlenstoffaserband biomechanisch geniigende Stabilitäterzielt werden.

     

Incidence of acromioclavicular joint complications after arthroscopic subacromial decompression.

We performed a chart and radiograph review of 173 patients (183 shoulders) who underwent arthroscopic subacromial decompression between 1991 and 1994 and had preoperative and postoperative radiographs. The study focused on the presence of preoperative acromioclavicular joint pathology, intraoperative violation of the acromioclavicular joint, extent of distal clavicle excision, and subsequent development of acromioclavicular joint symptoms. The 183 surgical procedures were divided into three groups: shoulders with subacromial decompression without acromioclavicular joint violation (103 of 183; 56%; group A); shoulders with subacromial decompression with acromioclavicular joint violation and partial distal clavicle resection (36 of 183; 20%; group B); and shoulders with subacromial decompression with complete distal clavicle resection (44 of 183; 24%; group C). Groups A and C had no postoperative sequelae in reference to the acromioclavicular joint. In contrast, 14 of the 36 shoulders (39%) in group B with a documented acromioclavicular joint violation and a partial distal clavicle resection developed acromioclavicular joint symptoms at an average of 8.4 months (range, 1.8 to 19 months) after surgery. This finding was statistically significant (P=.0001). The results of this study suggest that any violation of the acromioclavicular joint in the course of an arthroscopic subacromial decompression may jeopardize the result. The degree of violation is not helpful in predicting outcome. As a result of this study, we suggest an all-or-none surgical approach to the acromioclavicular joint and distal clavicle resection.     

锁骨钩钢板治疗肩锁关节完全脱位与锁骨外侧骨折

目的评价锁骨钩钢板治疗肩锁关节完全脱位与锁骨外端骨折的方法及效果。方法分析2001年5月至2005年5月22例患者运用锁骨钩钢板治疗肩锁关节完全脱位与锁骨外端骨折的疗效。结果平均随访20个月,按Lazz Cano疗效标准,优15例,良6例。结论锁骨钩钢板治疗肩锁关节完全脱位和锁骨远端骨折,符合生物力学要求,并发症少,是一种可靠有效的治疗方法。     

Biomechanical Analysis of Implanted Clavicle Hook Plates With Different Implant Depths and Materials in the Acromioclavicular Joint: A Finite Element Analysis Study

Clinical implantation of clavicle hook plates is often used as a treatment for acromioclavicular joint dislocation. However, it is not uncommon to find patients that have developed acromion osteolysis or had peri‐implant fracture after hook plate fixation. With the aim of preventing complications or fixation failure caused by implantation of inappropriate clavicle hook plates, the present study investigated the biomechanics of clavicle hook plates made of different materials and with different hook depths in treating acromioclavicular joint dislocation, using finite element analysis (FEA). This study established four parts using computer models: the clavicle, acromion, clavicle hook plate, and screws, and these established models were used for FEA. Moreover, implantations of clavicle hook plates made of different materials (stainless steel and titanium alloy) and with different depths (12, 15, and 18 mm) in patients with acromioclavicular joint dislocation were simulated in the biomechanical analysis. The results indicate that deeper implantation of the clavicle hook plate reduces stress on the clavicle, and also reduces the force applied to the acromion by the clavicle hook plate. Even though a clavicle hook plate made of titanium alloy (a material with a lower Young's modulus) reduces the force applied to the acromion by the clavicle hook plate, slightly higher stress on the clavicle may occur. The results obtained in this study provide a better reference for orthopedic surgeons in choosing different clavicle hook plates for surgery.     

锁骨中段骨折合并同侧肩锁关节脱位：诊断要点分析研究

目的探讨锁骨中段骨折合并同侧肩锁关节脱位的诊断要点,为临床早期诊断该类损伤提供参考。 方法通过分析国内外文献报道的病例,并回顾性分析本科室随访病例,从年龄、性别、受伤原因、锁骨中段骨折及肩锁关节脱位分型等方面进行分析。 结果共检索到19篇锁骨中段骨折伴同侧肩锁关节脱位的英文病例报道、7篇中文文献病例报道,其中有清晰术前X线片的病例共22例。同时,回顾性分析了本院临床随访的2例该类病例,因此,最终有24例病例纳入分析研究。其中,男16例、女8例;最小年龄为19岁,最大年龄为65岁,平均年龄为37岁。大部分由高能量损伤所致（21/24, 87.5%）。锁骨骨折类型分型：19例（19/24,79.2%）属于A型骨折,5例（5/24,20.8%）属于B型骨折;肩锁关节脱位分型：IV型12例（50.0%）、III型6例（25.0%）,VI型4例（16.7%）,V型2例（8.3%）;9例（9/24,37.5%）患者有合并损伤。 结论对于高能量损伤导致的相对简单类型的锁骨中段骨折,需高度怀疑有无同侧肩锁关节脱位,诊断要点如下：（1）详细询问受伤原因,了解受伤机制;（2）对所有锁骨中段骨折病例,需观察肩锁关节处有无肿胀、皮下青紫,并对肩锁关节及喙突处进行压痛体格检查,如有压痛,则高度怀疑肩锁关节损伤;（3）需仔细观察术前X线肩锁间隙及喙锁间隙变化,如锁骨中段骨折为相对简单类型,且为高能量损伤者,需高度怀疑,建议加拍对照位片及患侧肩关节CT检查;（4）术中锁骨中段骨折固定后,常规透视同侧肩锁关节。     

TightRope?

Surgical treatment of horizontally or vertically unstable acromioclavicular (AC) joint dislocations covers a wide range of surgical techniques, e.g. stabilization via a tension band, hooked tie plate or Bosworth screw. Many of these techniques are often accompanied by various complications so that a stabilizing, low complication and approximately physiological surgical treatment has moved increasingly into the focus of scientific interest. Through further development of the dynamic TightRope? system in syndesmosis surgery there is now the possibility to treat unstable AC joint dislocations in a similar manner. Advantages include improved cosmetic aspects through a less stressful surgical access as well as the reduction of postoperative infections and the fact that a second intervention to remove the metal implants is no longer necessary. Within the framework of biomechanical studies scientists were able to show that the TightRope? treatment was able to create a stable situation and to provide a sufficient load capacity.     

Biomechanical study of the ligamentous system of the acromioclavicular joint

The ligamentous structures of the acromioclavicular joint were studied by gross examination and quantitative measurement in twelve human cadaver specimens. Distances between insertions at various extreme positions of the clavicle were studied with the biplane radiographic technique. Ligamentous contributions to joint constraint under displacements were determined by performing load-displacement tests along with sequential sectioning of the ligaments. Twelve modes of joint displacement were examined. The acromioclavicular ligament acted as a primary constraint for posterior displacement of the clavicle and posterior axial rotation. The conoid ligament appeared to be more important than has been previously described. That ligament played a primary role in constraining anterior and superior rotation as well as anterior and superior displacement of the clavicle. The trapezoid ligament contributed less constraint to movement of the clavicle in both the horizontal and the vertical plane except when the clavicle moved in axial compression toward the acromion process. The various contributions of different ligaments to constraint changed not only with the direction of joint displacement but also with the amount of loading and displacement. For many directions of displacement, the acromioclavicular joint contributed a greater amount to constraint at smaller degrees of displacement, while the coracoclavicular ligaments, primarily the conoid ligament, contributed a greater amount of constraint with larger amounts of displacement.     

锁骨钩钢板内固定术后肩部疼痛和外展受限的分析

目的探讨采用锁骨钩钢板内固定治疗锁骨远端骨折和肩锁关节脱位术后并发肩部疼痛和肩关节外展受限的原因。方法将60例锁骨远端骨折和肩锁关节脱位患者随机分为A、B两组。锁骨钩钢板外侧钩的安置采用两种不同方式：A组（30例）患者术中仅显露锁骨骨折断端及肩锁关节,不显露肩峰,锁骨钩钢板外侧钩于肩锁关节后方盲插入肩峰下进行固定;B组（30例）患者同时显露肩峰,将锁骨钩钢板外侧钩紧贴肩峰于骨膜下插入进行固定,以减少钢板钩部与肩峰之间软组织嵌入。对两组术后出现患侧肩关节疼痛不适及外展受限发生率进行组间对比分析。结果 55例患者获得12-24个月随访,5例失访。肩关节疼痛及外展轻度受限B组28例中出现3例,发生率为10.7%;A组27例中出现9例,发生率为33.3%,两组比较差异有统计学意义（P〈0.05）。结论术中充分显露肩峰,紧贴肩峰插入锁骨钩钢板外侧钩,使外侧钩部与肩峰紧密贴合,可减少其间软组织嵌入和肩峰与钢板钩部撞击,从而减少术后肩关节疼痛及外展受限等并发症的发生率。     

改良双Endobutton技术治疗肩锁关节脱位和锁骨远端不稳定性骨折的肩关节功能评定

目的对经典的双Endobutton技术进行改良,治疗锁骨远端不稳定性骨折和Rock—woodⅢ型以上的肩锁关节脱位,探索新术式的疗效。方法2010年3月至2011年1月就诊的18例锁骨远端不稳定性骨折和Ⅲ型以上的肩锁关节脱位的患者,予以改良的双Endobutton技术重建喙锁韧带,术后予以Constant—Murley评分。结果术后随访4～10个月,本组14例疗效为优,4例为良,优良率为100％。未发生并发症。结论改良的双Endobutton技术重构锁骨远端的生物稳定性,术式简单易行,手术时间短,疗效满意。     

关节镜辅助下三束重建治疗急性Rockwood Ⅲ型肩锁关节脱位

目的探讨关节镜辅助下三束重建治疗急性Rockwood Ⅲ型肩锁关节脱位的临床疗效。 方法回顾性分析上海交通大学医学院附属新华医院骨科采用关节镜辅助下三束重建治疗21例急性Rockwood Ⅲ型肩锁关节脱位患者的资料,均为闭合性损伤。术后3、6、12个月对所有患者进行术后临床效果和影像学评价。根据术后影像学资料评估复位再丢失情况,采用Constant评分和上肢功能（disabilities of arm,shoulder and hand,DASH）评分评估患者肩关节功能。探讨术中关节镜辅助治疗的意义和价值。 结果术中关节镜探查发现4例合并软组织损伤,并进行一期镜下修复。所有患者术后均未发生喙突骨折和襻断裂。影像学评估提示术后6~12个月有6例患者（28.6%）出现轻度复位丢失,但与Constant评分和DASH评分无显著相关性,没有患者要求取出内固定。 结论关节镜辅助下三束重建治疗急性Rockwood Ⅲ型肩锁关节脱位是一种创伤小、安全、临床效果确切的手术方法。急性肩锁关节脱位通常由高能量损伤造成,在手术中关节镜探查肩关节能发现合并的软组织损伤,并进行一期修复,有利于肩关节功能的恢复,避免二次手术。     

Die laterale Klavikulafraktur – Grundlagen,OP-Indikationen,Versorgungstechniken

Fractures of the lateral clavicle are a rare entity and can usually be treated conservatively. Only dislocated fractures with disrupted coracoclavicular (CC) ligaments may require operative treatment. Many different surgical techniques have been described. The use of hook plates and k-wires is associated with higher complication rates. Similar to acromioclavicular (AC) joint dislocation, there is a trend towards minimally invasive and arthroscopically assisted procedures. The functional results are promising and the complication rates are low. From a biomechanical point of view, a combination of locked plate fixation and minimally invasive CC ligament reconstruction provides the highest stability. Newly developed preshaped angular stable implants may provide higher stability but are associated with implant-related soft tissue irritation and hardware removal is required more frequently.     

The arthroscopic mumford procedure: An analysis of results

A total of 50 arthroscopic distal clavicle resections were performed for acromioclavicular joint pathology at our institution between 1990 and 1993. Follow-up on 50 shoulders (100%) was obtained at an average postoperative time of 2 years. Data were collected via physical examination, radiograph review, University of California at Los Angeles (UCLA) shoulder score, and questionnaire. Average patient age was 42 years. Preoperatively all patients showed acromioclavicular joint tenderness, whereas 80% had a positive adduction test. The diagnosis of acromioclavicular degeneration was made by a combination of physical examination and radiographs (100%), acromioclavicular joint injection (4%), bone scan (44%), and magnetic resonance imaging (30%). Intraoperatively, a Claviculizer (Smith-Nephew Dyonics, Andover, MA) burr was used through standard portals in a subacromial approach to the acromioclavicular joint. There were no intraoperative complications. Forty-one patients (82%) had their general anesthetic augmented with an intrascalene block, and all procedures were done on an outpatient basis. The average distal clavicle resection was 14.8 mm. Calcifications within the resected clavicle zone were noted in the shoulders of four of the patients (16%) who returned for radiographic follow-up. The UCLA shoulder score ranked 47 shoulders (94%) good to excellent and 3 fair (6%). Subjective patient satisfaction recorded 47 (94%) good to excellent results, with an average pain relief grade of 87%. Fortyfive patients (98%) would recommend the procedure. The arthroscopic Mumford procedure effectively treats acromioclavicular joint pathology. The amount of bone removed can be precisely determined with the Claviculizer burr and reliably reproduced. The procedure has low associated morbidity and high patient satisfaction regarding functional outcome.     

锁骨钩钢板与克氏针张力带治疗肩锁关节脱位和锁骨远端骨折疗效比较

[目的]比较研究锁骨钩钢板与克氏针张力带治疗肩锁关节脱位和锁骨远端骨折的疗效。[方法]52例肩锁关节脱位或锁骨远端骨折患者，34例采用锁骨钩钢板、18例采用克氏针张力带内固定。回顾性分析比较其手术难易程度、治疗效果及并发症。[结果]术中两组手术难易程度无明显差异，P〉0．05；术后平均随访15个月，锁骨钩钢板组手术并发症发生率为0．0％，肩关节功能评定优良率为97．1％，优于克氏针张力带组的38．9％、72．2％，P〈0．05。[结论]锁骨钩钢板是一种在治疗肩锁关节脱位和锁骨远端骨折上优于克氏针张力带的新方法，值得推广。     

Painful conditions of the acromioclavicular joint.

The acromioclavicular (AC) joint may be affected by a number of pathologic processes, most commonly osteoarthritis, posttraumatic arthritis, and distal clavicle osteolysis. The correct diagnosis of a problem can usually be deduced from a thorough history, physical examination, and radiologic evaluation. Asymptomatic AC joint degeneration is frequent and does not always correlate with the presence of symptoms. Selective lidocaine injection enhances diagnostic accuracy and may correlate with surgical outcome. Nonoperative treatment is helpful for most patients, although those with osteolysis may have to modify their activities. In appropriately selected patients, open or arthroscopic distal clavicle resection is necessary to relieve symptoms. Recent biomechanical and clinical data emphasize the importance of capsular preservation and minimization of bone resection; however, the optimal amount of distal clavicle resection remains elusive. Patients with AC joint instability have poor results after distal clavicle resection.     

RockwoodⅢ型肩锁关节脱位保守治疗与自体腓骨长肌腱重建喙锁韧带治疗的疗效对比研究

目的比较保守治疗与自体腓骨长肌腱前侧半（anterior half of the peroneus longus tendon, AHPLT）重建喙锁韧带治疗Rockwood Ⅲ型肩锁关节脱位的疗效。 方法自2013年6月至2016年3月共收治36例Rockwood Ⅲ型肩锁关节脱位患者。根据治疗方式不同将患者分为重建喙锁韧带组（利用自体AHPLT重建技术治疗）15例和保守治疗组21例。记录术前及术后（或保守治疗后）1、3、6、12个月的肩关节Constant、Quick DASH、VAS评分综合评估患者肩关节功能情况,并通过影像学分析复位是否丢失。 结果重建喙锁韧带组和保守组在随访1年时,患侧Constant评分分别为95.27分和97.02分,均较术前或保守治疗前Constant评分49.8分和51.8分显著提高,差异有统计学意义（P<0.05）,重建组和保守组间Constant评分差异无统计学意义（P>0.05）。一年时Quick DASH评分重建组和保守组分别为6分和2.38分,均较术前或保守治疗前23.8分和16.15分显著降低（P<0.05）,重建组和保守组间Quick DASH评分差异无统计学意义（P>0.05）。一年时VAS评分重建组和保守组分别为0.33分和0.10分,均较术前或保守治疗前4.73分和4.38分显著降低（P<0.05）,重建组和保守组间VAS评分无统计学意义（P>0.05）。1个月时,重建组Constant评分43.4分,Quick DASH评分58分,VAS评分4.27分,疗效均较保守组Constant评分65.17分,Quick DASH评分36.19分,VAS评分2.48分差（P<0.05）。3个月时重建组与保守组Constant评分无明显差异,但保守组Quick DASH评分与VAS评分较重建组好（P<0.05）。6个月时,两组间Constant评分和Quick DASH评分差异无统计学意义（P>0.05）,而VAS评分保守组较重建组更低,差异有统计学意义（P<0.05）。影像学检查提示随访1年时,重建组15例患者中有3例发生复位丢失（20%）,保守组21例中发生复位丢失的有5例（23.81%）。重建组患者均无感染,锁骨、喙突骨折等并发症发生。 结论对于Rockwood Ⅲ型肩锁脱位患者,采用重建喙锁韧带治疗或者保守治疗均能达到较好的临床效果,在早期,采用保守治疗的患者其功能和疼痛优于重建韧带治疗的患者。     

肩锁关节解剖学研究和临床意义

目的研究肩锁关节骨性和静态稳定结构,为肩部手术提供详细形态学资料。方法对26例成人新鲜尸体标本进行解剖,观察肩锁关节解剖形态并测量相关骨性标志和韧带的形态学参数。结果锥状韧带和斜方韧带锁骨止点中心到锁骨远端距离分别为(43.67±6.30)mm和(25.25±3.06)mm,止点宽度分别为(16.92±4.25)mm和(10.33±1.32)mm。锥状韧带长度为(15.54±3.32)mm,角度为(-116.25±10.90)°;而斜方韧带长度为(9.63±2.28)mm,角度为(75.42±11.37)°。锥状韧带和斜方韧带喙突止点相距(8.96±3.00)mm,而锁骨止点距离(13.08±3.50)mm,两条韧带呈"V"形结构。结论本研究获得了肩锁关节及其周围组织的详细形态学参数,为该部位手术提供解剖学资料。进行锁骨远端手术时应避免损伤锥韧带和斜方韧带止点,切除锁骨远端应不超过10mm以避免损伤斜方韧带。行喙锁韧带重建时要注意重建其"V"形解剖结构,以更好恢复其生理功能。     

A modified method of coracoid transposition for the treatment of complete dislocation of acromioclavicular joint

Objective:To eport a new method of coracoid transpostiton for the treatment of complete dislocation of acromioclavicular joint and to evaluate its efficacy.Methods:We modified Eewar‘s surgical method as follows:(1)Two small incisions,a transversal incision on the acromioclavicular joint and a longitudinal incision on the coracoid ,were made instead of a conventional large arc incision from the acromion to coracoid.(2)The foreign body in the acromioclavicular joint was cleared out.Thechondral surface at the lateral segment of clavicle was resected to form a pseudarthrosis and meanwhile the residual joint capsule and ligaments were repaired.(3)The coracoid was moved to the anteroinferior edge of the clavicle instead of the anterior margin and (4)the coracoid was moved to the lateral border of the clavicle instead of the superior border of the coracoclavicular ligament.Results:The follow-up duration in 30patients of the series was from6to 72months(mean41months).Functional assessment was carried out by the criteria delineated previously by Karkson,in which Grade Awas in 24 cases,Grade Bin4cases,and Cin2.Conclusions:This modified technique,having less postoperative complications and less injuries to tissues and according well with the requitement of biomechanics,can achieve a stable reduction of acromioclavicular joint with a good functional and cosmetic result and thereore is preferable to use clinically on a large scale.     

Current concepts in the diagnosis and management of acromioclavicular dislocations

Not all complete dislocations of the acromioclavicular joint should be treated by one method alone. A classification of acromioclavicular dislocation is presented and is based upon the pathology of the injury. Grade I sprain results from a mild force that causes tearing of only a few fibers of the acromioclavicular joint. Grade II sprains are caused by a moderate force with a rupture of the capsule and acromioclavicular ligament. Grade III sprains result from a severe force that ruptures both the acromioclavicular and coracoclavicular ligaments and causes a dislocation of the joint. Grade IV dislocation may be associated with an avulsion fracture of the coracoclavicular ligament from the inferior lateral clavicle, severe tearing or other injury to the soft-tissue envelope about the lateral clavicle, or a buttonhole injury of the lateral clavicle. Grade V dislocation refers to a posterior displacement of the lateral clavicle from any cause, while Grade VI relates to an inferior lateral clavicle displacement. Grades I, II, and most Grade III injuries can be treated conservatively. The indications for open treatment of Grade III injuries are reviewed. It is recommended that Grade IV and most Grade V and VI dislocations be managed with open methods.     

Acromioclavicular reconstruction using autogenous semitendinosus tendon graft: results of revision surgery in chronic cases

Revision surgery of acromioclavicular dislocation is challenging owing to the altered anatomic relationships and the lack of stabilizing structures. In this study, an autogenous semitendinosus tendon graft was used for revision acromioclavicular stabilization, aiming at anatomic coracoclavicular reconstruction, as these patients had previously undergone a Weaver-Dunn procedure, which failed. Twelve patients were followed up clinically and radiographically for a mean of 49.5 months. The primary diagnosis was acromioclavicular joint dislocation Rockwood type III in 6, type IV in 4, and type V in 2 cases. At follow-up, the mean Constant score averaged 76.4 points. Pain relief was statistically significant (P < .01). Radiologic coracoclavicular distance and posterior displacement of the lateral clavicle in the Rockwood type IV cases decreased significantly (P < .01). We conclude that with this new technique of autogenous semitendinosus tendon graft replicating the anatomic ligamentous properties, good to excellent results can be achieved in revision cases of acromioclavicular reconstruction.