The effect of radial head fracture size on elbow kinematics and stability.

This study determined the effect of radial head fracture size and ligament injury on elbow kinematics. Eight cadaveric upper extremities were studied in an in vitro elbow simulator. Testing was performed with ligaments intact, with the medial collateral (MCL) or lateral collateral (LCL) ligament detached, and with both the MCL and LCL detached. Thirty degree wedges were sequentially removed from the anterolateral radial head up to 120 degrees . Valgus angulation and external rotation of the ulna relative to the humerus were determined for passive motion, active motion, and pivot shift testing with the arm in a vertical (dependent) orientation. Maximum varus-valgus laxity was calculated from measurements of varus and valgus angulation with the arm in horizontal gravity-loaded positions. No effect of increasing radial head fracture size was observed on valgus angulation during passive and active motion in the dependent position. In supination, external rotation increased with increasing fracture size during passive motion with LCL deficiency and both MCL and LCL deficiency. With intact ligaments, maximum varus-valgus laxity increased with increasing radial head fracture size. With ligament disruption, elbows were grossly unstable, and no effect of increasing radial head fracture size occurred. During pivot shift testing, performed with the ligaments intact, subtle instability was noted after resection of one-third of the radial head. In this in vitro biomechanical study, small subtle effects of radial head fracture size on elbow kinematics and stability were seen in both the ligament intact and ligament deficient elbows. These data suggest that fixation of displaced radial head fractures less than or equal to one-third of the articular diameter may have some biomechanical advantages; however, clinical correlation is required.     

The effect of radial head excision and arthroplasty on elbow kinematics and stability

BACKGROUND: Radial head fractures are common injuries. Comminuted radial head fractures often are treated with radial head excision with or without radial head arthroplasty. The purpose of the present study was to determine the effect of radial head excision and arthroplasty on the kinematics and stability of elbows with intact and disrupted ligaments. We hypothesized that elbow kinematics and stability would be (1) altered after radial head excision in elbows with intact and disrupted ligaments, (2) restored after radial head arthroplasty in elbows with intact ligaments, and (3) partially restored after radial head arthroplasty in elbows with disrupted ligaments. METHODS: Eight cadaveric upper extremities were studied in an in vitro elbow simulator that employed computer-controlled actuators to govern tendon-loading. Testing was performed in stable, medial collateral ligament-deficient, and lateral collateral ligament-deficient elbows with the radial head intact, with the radial head excised, and after radial head arthroplasty. Valgus angulation and rotational kinematics were determined during passive and simulated active motion with the arm dependent. Maximum varus-valgus laxity was measured with the arm in a gravity-loaded position. RESULTS: In specimens with intact ligaments, elbow kinematics were altered and varus-valgus laxity was increased after radial head excision and both were corrected after radial head arthroplasty. In specimens with disrupted ligaments, elbow kinematics were altered after radial head excision and were similar to those observed in specimens with a native radial head after radial head arthroplasty. Varus-valgus laxity was increased after ligament disruption and was further increased after radial head excision. Varus-valgus laxity was corrected after radial head arthroplasty and ligament repair; however, it was not corrected after radial head arthroplasty without ligament repair. CONCLUSIONS: Radial head excision causes altered elbow kinematics and increased laxity. The kinematics and laxity of stable elbows after radial head arthroplasty are similar to those of elbows with a native radial head. However, radial head arthroplasty alone may be insufficient for the treatment of complex fractures that are associated with damage to the collateral ligaments as arthroplasty alone does not restore stability to elbows with ligament injuries.     

Laxity of the elbow after experimental excision of the radial head and division of the medial collateral ligament. Efficacy of ligament repair and radial head prosthetic replacement: a cadaver study

We studied the stabilising effect of prosthetic replacement of the radial head and repair of the medial collateral ligament (MCL) after excision of the radial head and section of the MCL in five cadaver elbows. Division of the MCL increased valgus angulation (mean 3.9 +/- 1.5 degrees) and internal rotatory laxity (mean 5.3 +/- 2.0 degrees). Subsequent excision of the radial head allowed additional valgus (mean 11.1 +/- 7.3 degrees) and internal rotatory laxity (mean 5.7 +/- 3.9 degrees). Isolated replacement of the radial head reduced valgus laxity to the level before excision of the head, while internal rotatory laxity was still greater (2.8 +/- 2.1 degrees). Isolated repair of the MCL corrected internal rotatory laxity, but a slight increase in valgus laxity remained (mean 0.7 +/- 0.6 degrees). Combined replacement of the head and repair of the MCL restored stability completely. We conclude that the radial head is a constraint secondary to the MCL for both valgus displacement and internal rotation. Isolated repair of the ligament is superior to isolated prosthetic replacement and may be sufficient to restore valgus and internal rotatory stability after excision of the radial head in MCL-deficient elbows.     

Valgus stability of the elbow. A definition of primary and secondary constraints

The stabilizing structures of the elbow that resist valgus stress were studied with a tracking device in a model simulating active motion and muscle activity. By varying the order of serial release of the medial collateral ligament complex and removal of the radial head, each structure's contribution to valgus stability against the effect of gravity was determined. In the otherwise intact elbow, absence of the radial head does not significantly alter the three-dimensional characteristics of motion in the elbow joint. Isolated medial collateral release, on the other hand, causes increases in abduction rotation of about 6 degrees-8 degrees in magnitude. Releasing both structures results in gross abduction laxity and elbow subluxation. This study defines the medial collateral ligament (MCL) as the primary constraint of the elbow joint to valgus stress and the radial head as a secondary constraint. This definition facilitates the proper management of patients with radial head fractures and MCL disruption. The comminuted radial head fracture uncomplicated by MCL insufficiency should be treated by excision without the need for an implant and without concern of altering the normal kinematics of the elbow.     

Fractures of the capitellum

Forty intact cadaver elbows were studied to determine the contribution of the capitellum to elbow stability. With the elbow at 10 degrees of flexion, valgus motion of the elbow after capitellum excision demonstrated a minimal increase. Although some increase in valgus motion did occur after capitellum excision and radial head resection it was not until the ulnar collateral ligament was released that a severe valgus deformity was produced. In addition, isolated capitellum excisions occurring with release of the medial collateral ligament produced severe valgus motion, demonstrating the importance of medial structures to elbow stability. The cadaver study suggests excision of the capitellum in the otherwise intact elbow has little effect on valgus motion. Over the past 15 years, 17 patients with fractures of the capitellum were treated. Followup at greater than 1 year utilizing various treatment modalities is reported. Although closed reduction gave the best result, acceptable results were also obtained by open reduction and internal fixation and excision. Our clinical findings corroborated the cadaver findings in that valgus instability of the elbow only occurred when fracture of the capitellum was associated with medial ligament injuries.     

Rehabilitation of the Medial- and Lateral Collateral Ligament-deficient Elbow: An In Vitro Biomechanical Study

DesignIn vitro biomechanical research using an elbow motion simulator.IntroductionThe optimal rehabilitation of elbow dislocations with medial collateral ligament (MCL) and lateral collateral ligament (LCL) injuries has not been defined.PurposeTo determine a safe rehabilitation protocol for elbow dislocations with MCL and LCL injuries.MethodsEight cadaveric elbows underwent simulated active and passive motions with the arm in multiple orientations. Varus–valgus angulation and internal–external rotation of the ulna relative to the humerus were quantified for the intact joint and with injured MCL and LCL.ResultsActive motion with injured MCL and LCL in the horizontal and vertical orientations resulted in kinematics similar to the intact elbow, whereas passive motion resulted in significant kinematic alterations. Marked elbow instability was noted in the varus and valgus orientations using both active and passive motion.ConclusionsElbows with MCL and LCL injuries should be rehabilitated using active motion in the horizontal or vertical orientations.Level of EvidenceBasic science research.     

Standard surgical protocol to treat elbow dislocations with radial head and coronoid fractures

BACKGROUND: The results of elbow dislocations with associated radial head and coronoid fractures are often poor because of recurrent instability and stiffness from prolonged immobilization. We managed these injuries with a standard surgical protocol, postulating that early intervention, stable fixation, and repair would provide sufficient stability to allow motion at seven to ten days postoperatively and enhance functional outcome. METHODS: We retrospectively reviewed the results of this treatment performed, at two university-affiliated teaching hospitals, in thirty-six consecutive patients (thirty-six elbows) with an elbow dislocation and an associated fracture of both the radial head and the coronoid process. Our surgical protocol included fixation or replacement of the radial head, fixation of the coronoid fracture if possible, repair of associated capsular and lateral ligamentous injuries, and in selected cases repair of the medial collateral ligament and/or adjuvant hinged external fixation. Patients were evaluated both radiographically and with a clinical examination at the time of the latest follow-up. RESULTS: At a mean of thirty-four months postoperatively, the flexion-extension arc of the elbow averaged 112 degrees +/- 11 degrees and forearm rotation averaged 136 degrees +/- 16 degrees. The mean Mayo Elbow Performance Score was 88 points (range, 45 to 100 points), which corresponded to fifteen excellent results, thirteen good results, seven fair results, and one poor result. Concentric stability was restored to thirty-four elbows. Eight patients had complications requiring a reoperation: two had a synostosis; one, recurrent instability; four, hardware removal and elbow release; and one, a wound infection. CONCLUSIONS: Use of our surgical protocol for elbow dislocations with associated radial head and coronoid fractures restored sufficient elbow stability to allow early motion postoperatively, enhancing the functional outcome. We recommend early operative repair with a standard protocol for these injuries.     

The effect of medial collateral ligament repair tension on elbow joint kinematics and stability

PURPOSE: Medial collateral ligament (MCL) repair is commonly performed for the management of acute or subacute instability after elbow dislocations and fracture-dislocations. The effectiveness of transosseous repair of the MCL, as is typically performed clinically, in restoring the normal kinematics and stability of the elbow is of interest as is the effect of MCL tensioning on the initial stability of the elbow. The purpose of this study was to determine whether suture repair of the MCL is able to restore the normal kinematics and stability of the elbow and to determine the optimal initial MCL repair tension. METHODS: Six cadaveric upper extremities were mounted in an upper limb joint simulator. Simulated active and passive elbow flexion was generated while the kinematics were measured with the arm in the dependent and the valgus gravity-loaded orientations. After testing the intact elbow, the MCL was released at its humeral attachment and repaired using a transosseous suture technique at three different repair tensions: 20, 40, and 60 N. RESULTS: Medial collateral ligament repair using a transosseous suture technique restored the kinematics and stability of the MCL-deficient elbow. Motion pathways were affected by the magnitude of initial MCL tension. For all arm orientations and forearm positions, the 20-N and 40-N repairs were not statistically different from each other or from the intact MCL. The 60-N repairs, however, were often statistically different than the other groups, suggesting an overtightening that tended to pull the ulna into a varus position-especially in the midrange of flexion. CONCLUSIONS: These data suggest that MCL repair using transosseous sutures provide adequate joint stability to permit early motion. There is a broad range of acceptable tensions for MCL repair, which is a favorable, clinically relevant finding. Clinical studies are needed to validate these in vitro results.     

Coronoid process and radial head as posterolateral rotatory stabilizers of the elbow

BACKGROUND: The purpose of this study was to evaluate the role of the radial head and the coronoid process as posterolateral rotatory stabilizers of the elbow and to determine the stabilizing effect of radial head replacement and coronoid reconstruction. METHODS: The posterolateral rotatory displacement of the ulna was measured after application of a valgus and supinating torque (1). in seven intact elbows, (2). after radial head excision, (3). after sequential resection of the coronoid process, (4). after subsequent insertion of each of two different types of metal radial head prostheses (a rigid implant and a bipolar implant with a floating cup), and (5). after subsequent reconstruction of the coronoid with each of two different techniques in the same cadaveric elbow. RESULTS: The posterolateral rotatory laxity averaged 5.4 degrees in the intact elbows. The surgical approach used in this study insignificantly increased the mean laxity to 9 degrees. Excision of the radial head in an elbow with intact collateral ligaments caused a mean posterolateral rotatory laxity of 18.6 degrees (p < 0.0001). Additional removal of 30% of the height of the coronoid fully destabilized the elbows, always resulting in ulnohumeral dislocation despite intact ligaments. Implantation of a rigid radial head prosthesis stabilized the elbows. However, a mean laxity of 16.9 degrees persisted after insertion of a floating prosthesis (p < 0.0001). The elbows with a defect of 50% or 70% of the coronoid, loss of the radial head, and intact ligaments could not be stabilized by radial head replacement alone, but additional coronoid reconstruction restored stability. CONCLUSIONS: The results of this study suggest that the coronoid and the radial head contribute significantly to posterolateral rotatory stability.     

Surgical management of medial and lateral elbow instability secondary to acute atypical complex elbow dislocation: Case report and literature review

Introduction and importanceElbow dislocation is common in adults, and complex elbow dislocations are generally associated with bone fractures. Anteromedial coronoid fracture, in association with lateral collateral ligament (LCL) disruption, often results from varus posteromedial forces. “Terrible triad” injuries are more likely to result from valgus posterolateral forces. However, our case presentation has combined medial and lateral elbow instability in addition to “terrible triad” injury of the elbow with no radial head injury.Case presentationThe patient was a 38-year-old man with an atypical complex elbow dislocation. He was successfully treated by stabilizing the medial epicondyle and coronoid anterolateral facet fractures, in addition to LCL repair and medial collateral ligament (MCL) reconstruction. A radial head fracture was unnoted. The procedure yielded satisfactory functional outcome, with a stable and painless full elbow range of motion.Clinical discussionMulti-ligament injuries with coronoid fractures result in highly unstable elbow joints, forming a variant of the “terrible triad” injury. Surgical options vary according to the surgeon’s experience and equipment availability. In this case, direct LCL repair and MCL reconstruction were performed and were well tolerated. Elbow stability improved and the patient experienced improved functionality with minimal pain. However, it may be premature to report a definite outcome in this case because of short follow-up time postoperatively.ConclusionThe injury described in this case has a unique presentation as a multi-ligamentous injury will make the elbow very unstable. Thus, careful clinical judgment, knowledge, and experience are needed to identify the underlying injury and for optimal management.     

重建肘关节外翻稳定性的生物力学研究

目的　评价肘关节桡骨头 (radial head,RH)切除、尺侧副韧带 (medial collateral ligament,MCL )损伤以及 RH假体置换、MCL重建后的外翻稳定性。　方法　新鲜成人尸体上肢标本 12侧 ,制成肘关节“骨 -韧带”标本 ,在2 N· m的外翻力矩作用下 ,分别在肘关节 0°、30°、6 0°、90°和 12 0°伸屈时 ,测量肘关节外翻松弛度 :1完整肘关节(n=12 ) ;2 MCL切断 (n=6 ) ;3RH切除 (n=6 ) ;4 MCL切断 +RH切除 (n=12 ) ;5 RH假体置换 (n=6 ) ;6 MCL重建(n=6 ) ;7RH假体置换 +MCL重建 (n=12 )。用 SPSS 10 .0统计软件包作方差分析 ,比较各组的外翻稳定性。　结果　完整肘关节的平均外翻松弛度最小 ;RH切除后 ,外翻松弛度增大 ;单纯 MCL切断 ,外翻松弛度大于单纯 RH切除 (P<0 .0 1) ;MCL切断 +RH切除 ,外翻稳定性最差 ;行 RH假体置换 ,对稳定性有改善 ;MCL重建与完整 MCL差异无统计学意义 (P>0 .0 5 ) ;RH假体置换同时重建 MCL ,效果最好。　结论　 MCL是抵抗肘关节外翻应力最主要的因素 ,RH是次要因素。在重建肘关节的外翻稳定性方面 ,MCL的重建比 RH的假体置换更重要。在无条件行 RH假体置换时 ,修复MCL是较好的手术方式。     

Metallic radial head arthroplasty improves valgus stability of the elbow

The stabilizing influence of radial head arthroplasty was studied in eight medial collateral ligament deficient anatomic specimen elbows. An elbow testing apparatus, which used computer controlled pneumatic actuators to apply tendon loading, was used to simulate active elbow flexion. The motion pathways of the elbow were measured using an electromagnetic tracking device, with the forearm in supination and pronation. As a measure of stability, the maximum varus to valgus laxity over the range of elbow flexion was determined from the difference between varus and valgus gravity loaded motion pathways. After transection of the medial collateral ligament, the radial head was excised and replaced with either a silicone or one of three metallic radial head prostheses. Medial collateral ligament transection caused a significant increase in the maximum varus to valgus laxity to 18.0 degrees +/- 3.2 degrees. After radial head excision, this laxity increased to 35.6 degrees +/- 10.3 degrees. The silicone implant conferred no increase in elbow stability, with a maximum varus to valgus laxity of 32.5 degrees +/- 15.5 degrees. All three metallic implants improved the valgus stability of the medial collateral ligament deficient elbow, providing stability similar to the intact radial head. The use of silicone arthroplasty to replace the radial head in the medial collateral ligament deficient elbow must be questioned. Metallic radial head arthroplasty provides improved valgus stability, approaching that of an intact radial head.     

Contribution of monoblock and bipolar radial head prostheses to valgus stability of the elbow.

BACKGROUND: The purpose of this study was to evaluate the stabilizing effect of radial head replacement in cadaver elbows with a deficient medial collateral ligament. METHODS: Passive elbow flexion with the forearm in neutral rotation and in 80 degrees of pronation and supination was performed under valgus and varus loads (1) in intact elbows, (2) after a surgical approach (lateral epicondylar osteotomy of the distal part of the humerus), (3) after release of the anterior bundle of the medial collateral ligament, (4) after release of the anterior bundle of the medial collateral ligament and resection of the radial head, and (5) after subsequent replacement of the radial head with each of three different types of radial head prostheses (a Wright monoblock titanium implant, a KPS bipolar Vitallium [cobalt-chromium]-polyethylene implant, and a Judet bipolar Vitallium-polyethylene-Vitallium implant) in the same cadaver elbow. Total valgus elbow laxity was quantified with use of an electromagnetic tracking device. RESULTS: The mean valgus laxity changed significantly (p < 0.001) as a factor of constraint alteration. The greatest laxity was observed after release of the medial collateral ligament together with resection of the radial head (11.1 degrees +/- 5.6 degrees). Less laxity was seen following release of the medial collateral ligament alone (6.8 degrees +/- 3.4 degrees), and the least laxity was seen in the intact state (3.4 degrees +/- 1.6 degrees). Forearm rotation had a significant effect (p = 0.003) on valgus laxity throughout the range of flexion. The laxity was always greater in pronation than it was in neutral rotation or in supination. The mean valgus laxity values for the elbows with a deficient medial collateral ligament and an implant were significantly greater than those for the medial collateral ligament-deficient elbows before radial head resection (p < 0.05). The implants all performed similarly except in neutral forearm rotation, in which the elbow laxity associated with the Judet implant was significantly greater than that associated with the other two implants. CONCLUSIONS AND CLINICAL RELEVANCE: This study showed that a bipolar radial head prosthesis can be as effective as a solid monoblock prosthesis in restoring valgus stability in a medial collateral ligament-deficient elbow. However, none of the prostheses functioned as well as the native radial head, suggesting that open reduction and internal fixation to restore radial head anatomy is preferable to replacement when possible.     

Elbow dislocation with intra-articular fracture: the results of operative treatment without repair of the medial collateral ligament

PURPOSE: To determine the effectiveness of a protocol for the treatment of fracture-dislocations of the elbow based on the concept that, if dislocation of the elbow with associated fractures can be made to resemble a simple elbow dislocation by repairing or reconstructing the fractured structures, repair of the medial collateral ligament (MCL) will not be necessary. METHODS: Over a 5-year period, a single surgeon operated on 34 patients with a posterior dislocation of the elbow associated with one or more intra-articular fractures. The mean age of these 19 men and 15 women was 48 years. Associated fractures included the capitellum, trochlea, and lateral epicondyle in 3 patients; the olecranon in 1 patient; and the radial head in 30 patients (with concomitant fracture of the coronoid process-the so-called "terrible triad" of the elbow-in 22 patients, and concomitant fracture of the coronoid and olecranon in 1 patient). Operative treatment consisted of open reduction internal fixation (ORIF) or prosthetic replacement of all fractures and reattachment of the origin of the lateral collateral ligament (LCL) complex to the lateral epicondyle. The MCL was not repaired. RESULTS: Two patients (1 with a terrible triad injury and 1 with fracture of the capitellum and trochlea) had postoperative instability related to noncompliance, had reconstructive procedures, and were considered failures. An average of 32 months after injury, the remaining 32 patients regained an average of 120 degrees ulnohumeral motion and 142 degrees forearm rotation. Twenty-five of 34 patients (74%) had good or excellent results according to the system of Broberg and Morrey. Patients with terrible triad injuries had an average of 117 degrees ulnohumeral motion and 137 degrees forearm rotation, and 17 of 22 patients (77%) had good or excellent results. CONCLUSIONS: MCL repair is unnecessary in the treatment of dislocation of the elbow with associated intra-articular fractures, provided that the articular fractures and the LCL are repaired or reconstructed.     

Radial head fracture in the medial collateral ligament deficient elbow; biomechanical comparison of fixation, replacement and excision in human cadavers

A widely used clinical recommendation is that in the presence of medial collateral ligament injuries, two-part radial head fractures should be fixed rather than excising or replacing the radial head. Direct biomechanical data comparing fracture fixation, radial head replacement and excision in a human cadaveric elbow model, have not been previously described. Such comparison is clinically important as with the increasing availability of radial head implants and promising follow up results, the role of radial head replacement in fracture management may have to be redefined. In this study, five fresh cadaveric elbows had radial head fracture creation and medial collateral ligament division, fracture fixation, radial head replacement and excision. Valgus and varus laxity were determined using an electromagnetic tracking system. Radial head replacement leads to a similar valgus (P=0.80) [corrected] laxity as compared to radial head fixation. Radial head excision resulted in a significantly greater valgus laxity as compared to radial head fixation (P=0.02) or replacement (P=0.03). Both radial head excision and replacement led to a greater varus laxity as compared to fixation. Our results suggest that in the elbow with medial collateral ligament injury and two-part radial head fracture, fixation is overall biomechanically superior as compared to replacement and excision.     

Importance of a radial head component in Sorbie unlinked total elbow arthroplasty

The effects of a radial head component on total elbow arthroplasty kinematics and stability were evaluated using an anatomic design unlinked total elbow prosthesis. An electromagnetic tracking device recorded motion and varus and valgus displacements under various conditions in 10 cadaveric elbows. The motion patterns of the intact elbows and the Sorbie-Questor total elbow prostheses with a radial head component were similar, as both tended to have a valgus position in extension, varus at midflexion, and more valgus toward full flexion. Under conditions of simulated muscle loading, the maximum valgus and varus laxity of the elbow prosthesis was, on average, 8.6 degrees +/- 4.0 degrees greater than normal. Without the radial head component, however, significant kinematic disturbances and instabilities were seen. The varus and valgus displacements were 13.3 degrees +/- 5.5 degrees greater than the intact elbows. One total elbow arthroplasty without a radial head dislocated during testing. Increasing the muscle loading across the elbow significantly enhanced dynamic stability of the total elbow arthroplasties, especially in the extension half of elbow motion where instability is greatest. However, this dynamic enhancement of stability was seen only in those elbows in which the radial head component had been implanted. The radial head component is an important stabilizer, particularly in extension for this prosthesis, and possibly for other unlinked total elbow prostheses. Although instability of unlinked prostheses depends on the prosthetic design, the use of a radial head replacement may be an important factor in preventing such instability. Perhaps even more importantly, a radial head component balances the load distribution across the articulation, which could decrease stress on the ulnohumeral articulation and therefore possibly reduce polyethylene wear, osteolysis, and loosening.     

肘关节尺侧副韧带的修复重建

目的 评价桡骨头切除、尺侧副韧带(medial collateral ligament,MCL) 修复或重建手术治疗桡骨头粉碎性骨折合并MCL损伤的临床效果.方法 2000年9月-2006年4月,对18例桡骨头粉碎性骨折合并MCL损伤患者,手术行桡骨头切除的同时,对MCL采用直接缝合修复或带蒂筋膜重建治疗.其中男12例,女6例;年龄21～57岁.跌扑伤或高处坠落伤10例,交通事故伤8例.骨折按Mason分类,Ⅲ型13例,Ⅳ型5例.15例于伤后2周内手术;3例陈旧损伤,分别于伤后4、6和14个月手术.手术修复MCL4例,重建MCL14例. 结果 术后18例均获随访1～5年,平均3年.根据 Broberg 等制定的肘关节功能评定标准,优4例,良12例,可 1 例,差 1 例,优良率为 88.9%.3 例肘部轻度疼痛,1 例中度疼痛,14 例无疼痛.肘关节伸屈活动范围 110～140°,平均130°.前臂旋前 35～85°,平均 75°;前臂旋后 65～89°,平均 80°.患侧握力较健侧减少3%～28%,平均15%;伸肘力量减少8%～39%,平均30%;屈肘力量减少7%～29%,平均18%;旋前力量减少7%～31%,平均20%;旋后力量减少15%～45%,平均25%;患侧与健侧在相同外翻应力(外翻力矩2 Nm) 下X线片提携角增加 0～11°,平均 5°.以上指标患侧与健侧比较差异均有统计学意义(P<0.05). 结论 MCL 是抵抗肘关节外翻应力最主要的因素,在无条件行桡骨头假体置换时,行桡骨头切除、修复MCL 是一种有效的手术方式,但远期效果仍需随访.     

The contribution of the coronoid and radial head to the stability of the elbow

We undertook this study to determine the minimum amount of coronoid necessary to stabilise an otherwise intact elbow joint. Regan-Morrey types II and III, plus medial and lateral oblique coronoid fractures, collectively termed type IV fractures, were simulated in nine fresh cadavers. An electromagnetic tracking system defined the three-dimensional stability of the ulna relative to the humerus. The coronoid surface area accounts for 59% of the anterior articulation. Alteration in valgus, internal and external rotation occurred only with a type III coronoid fracture, accounting for 68% of the coronoid and 40% of the entire articular surface. A type II fracture removed 42% of the coronoid articulation and 25% of the entire articular surface but was associated with valgus and external rotational changes only when the radial head was removed, thereby removing 67% of the articular surface. We conclude that all type III fractures, as defined here, are unstable, even with intact ligaments and a radial head. However, a type II deficiency is stable unless the radial head is removed. Our study suggests that isolated medial-oblique or lateral-oblique fractures, and even a type II fracture with intact ligaments and a functional radial head, can be clinically stable, which is consistent with clinical observation.     

肘关节"恐怖三联征"的手术治疗-改良手术技术及初步结果报道

目的 总结肱尺关节后脱位合并桡骨头和尺骨冠状突骨折的手术治疗体会.方法 回顾5例典型肘关节"恐怖三联征"的手术治疗结果.手术方法包括:经肘关节外侧入路予桡骨头骨折内固定、修补外侧副韧带及伸肌总腱止点.经肘关节内侧径路固定尺骨冠状突,修复肘关节周围关节囊和内外侧副韧带损伤.最后使用肘关节铰链式外固定支架固定肱尺关节脱位,恢复肘关节同心圆稳定性.于术后1、3、6个月及随访结束时,进行影像学和临床检查评估.结果 5例平均手术时间为76 min(60-150 min),平均随访时间8.8个月(3-13个月).外固定支架拆除时间6周(4-9周).至随访末患者肘关节活动度平均为(127±25)°.按照Mayo肘关节评分平均为87分(80-95分),优2例,良3例.无浅表或深部感染、皮肤无坏死、无骨化性肌炎等并发症.结论 通过手术内固定或修补肘关节稳定结构结合外固定支架维持肘关节同心圆解剖关系可以明显改善肘关节"恐怖三联征"患者肘关节的功能及预后,对此类损伤建议采用内固定结合外固定治疗.     

A figure-eight suture loop with Kirschner wires for fixation of anteromedial coronoid process fractures: A case series

PurposeSufficient fixation of an anterior or anteromedial facet fracture of the coronoid process in fracture-dislocation of elbow is important to maintain joint stability. The purpose of this study was to report our experience with 11 patients who were managed with an original fixation technique using a “figure-eight” suture loop.MethodsFrom February 2010 to March 2011, 11 cases with a fracture of the anterior or anteromedial facet of the coronoid process were treated by coronoid fixation using a figure-eight suture loop. For cases with comminuted fractures, to prevent a suture from sliding into the fracture line, a 3- or 4-hole phalanx plate was enclosed in the suture loop to compress multiple fragments. Accompanying injuries, such as a radial head fracture or olecranon fracture, were fixed with repair of lateral collateral ligament injuries.ResultsOn final evaluations at an average of 18 months after injury, the mean elbow arc of motion was 125.5° and the mean forearm rotation arc of 124.1°. All fractures were united with an average postoperative score according to the Mayo Elbow Performance Index of 91 points. All patients achieved satisfactory scores (seven excellent, four good). All 11 fractures were united at final follow-up with no joint incongruity, dislocation, or subluxation of the injured elbow.ConclusionsThe figure-eight suture loop technique is an easy and effective technique to fix anterior or anteromedial facet fractures of the coronoid process.