Anterior bundle of ulnar collateral ligament: evaluation of anatomic relationships by using MR imaging, MR arthrography, and gross anatomic and histologic analysis

PURPOSE: To evaluate the gross and microscopic anatomy and the magnetic resonance (MR) imaging and MR arthrographic appearance of the anterior bundle of the ulnar collateral ligament (UCL) of the elbow. MATERIALS AND METHODS: The origin and insertion of the anterior bundle of the UCL, the bundle's relationship to the overlying flexor tendons, and the presence of a layered configuration were assessed through inspection and dissection of an elbow specimen. T1-weighted spin-echo MR imaging and MR arthrography in standard imaging planes and a coronal oblique plane were performed in eight other elbow specimens. Additional MR arthrography was performed in four specimens by using the coronal plane with the elbow in 20 degrees of flexion. The specimens were then cut in planes corresponding to those of the MR images. Histologic analysis of two specimens was performed. RESULTS: The anterior bundle of the UCL appeared as a low-signal-intensity structure on T1-weighted spin-echo MR and MR arthrographic images. It consisted of a uniform layer of parallel collagen fibers attaching proximally to the base of the medial epicondyle of the humerus and distally to the medial aspect of the coronoid process of the ulna (sublime tubercle). A layer of synovium separated the anterior bundle from the more superficial tendon of the flexor digitorum superficialis muscle. MR imaging-anatomic comparison in four (50%) specimens revealed separation between the anterior bundle of the UCL and the sublime tubercle. Results of histologic analysis of two of these specimens confirmed insertion of the anterior bundle of the UCL 3 and 4 mm distal to the articular margin. Ligamentous degeneration was detected in only one of these specimens. CONCLUSION: There is variability in the distal insertion of the anterior bundle, and this suggests that caution should be exercised in the diagnosis of its partial detachment from the sublime tubercle of the ulna.     

Subchondral bone infractions in acute ligamentous knee injuries demonstrated on bone scintigraphy and magnetic resonance imaging.

Bone scintigraphy is used to detect radiographically silent fractures. Magnetic resonance imaging (MRI) is currently used to screen knee injuries for cartilage and ligament damage. MRI also delineates bone marrow and fractures. We investigated the bone scintigraphic findings in patients who had subchondral bone injuries demonstrated on MRI. Thirteen patients underwent MRI, three-phase bone scintigraphy with SPECT, and arthroscopic surgery after sustaining acute traumatic hemarthrosis of a knee. They all had clinically unsuspected subchondral bone injuries demonstrated on MRI with normal radiographs and normal overlying articular cartilage at arthroscopy, consistent with occult fractures. All showed focal bone repair on scintigraphy. Two of the 13 patients showed additional bone injuries only on bone scan. Two other patients scintigraphically showed focal bone repair at the medial femoral condyle due to avulsion of the medial collateral ligament. SPECT was easier to interpret than multi-view planar imaging. Bone scintigraphy confirms subchondral fractures demonstrated on MRI but also demonstrates ligament avulsion injuries and additional more subtle bone injuries.     

Biomechanical evaluation of a new ulnar collateral ligament reconstruction technique with interference screw fixation

BACKGROUND: Techniques for ulnar collateral ligament reconstruction have evolved. HYPOTHESIS: Ulnar collateral ligament reconstruction with interference screw fixation restores elbow kinematics and failure strength to that of the native ligament. STUDY DESIGN: Controlled laboratory study. METHODS: Of 10 matched pairs of cadaveric elbows, one underwent kinematic testing under conditions of an intact, released, and reconstructed ligament. Single 5-mm diameter bone tunnels were created at the isometric anatomic insertion sites on the medial epicondyle and sublime tubercle. Graft fixation was achieved with 5 x 15 mm soft tissue interference screws. The reconstructed and contralateral intact elbows were then tested to failure. RESULTS: Average stiffness for intact elbows (42.81 +/- 11.6 N/mm) was significantly greater than for reconstructed elbows (20.28 +/- 12.5 N/mm). Ultimate moment for intact elbows (34.0 +/- 6.9 N.m) was not significantly different from reconstructed elbows (30.6 +/- 19.2 N.m). Release of the ulnar collateral ligament caused a significant increase in valgus instability. Reconstruction restored valgus stability to near that of the intact elbow. CONCLUSIONS: With this reconstruction method, failure strength was comparable with that of the native ligament and physiologic elbow kinematics were reliably restored. Clinical Relevance: This technique returns elbow kinematics to near normal, with less soft tissue dissection and risk of ulnar nerve injury and ease of graft insertion, tensioning, and fixation.     

Ulnar collateral ligament injury in the overhead athlete

The ulnar collateral ligament (UCL), particularly the anterior portion of the anterior oblique ligament, is the primary static contributor to elbow valgus stability. UCL injuries are most common in athletes participating in overhead sports. Acute and chronic injuries to the UCL result in valgus instability, which may predispose the athlete to the development of disabling secondary elbow conditions. Provocative physical examination maneuvers include the valgus abduction test, the modified milking maneuver, and the moving valgus stress test. Plain radiographs and magnetic resonance imaging are the most common imaging modalities, although ultrasonography and computed tomography arthrograms can alternatively be used. UCL injuries can be treated initially with rest, anti-inflammatory medications, bracing, and/or physical therapy. Acute avulsion injuries can be repaired, especially in those under 20 years of age, but most UCL tears are now treated with reconstruction. Modifications of the Jobe figure-of-8 technique, and now the Altchek docking technique, are the most common reconstruction techniques. Many new and hybrid techniques have been described with limited clinical experience in the literature. Current techniques offer the athlete a greater than 90% chance of return to play at their preinjury level.     

Stress injury of the proximal ulna in professional baseball players

BACKGROUND: To date, stress injury of the proximal ulna has been infrequently reported as a cause of elbow pain in the throwing athlete. PURPOSE: We describe a syndrome of osseous stress injury of the proximal ulna in the professional throwing athlete. STUDY DESIGN: Retrospective review. METHODS: We evaluated the clinical, radiographic, and magnetic resonance imaging findings of seven professional baseball players with osseous stress injury of the proximal ulna. RESULTS: Plain radiographs of the involved elbows failed to demonstrate any significant findings. All of the clinically significant lesions were detected with magnetic resonance imaging. In addition, magnetic resonance imaging was found to be of value in following the course of healing of the injuries. All of the lesions originated on the posteromedial aspect of the proximal ulna. The ulnar collateral ligament was intact in all seven athletes. One athlete had two occurrences of this injury. Six of the seven athletes returned to their previous level of play after a nonoperative course of treatment. CONCLUSIONS: We believe that this injury should be considered in the differential diagnosis of elbow pain in the throwing athlete. Magnetic resonance imaging is the diagnostic test of choice when this injury is suspected.     

尺骨冠状突骨折16例疗效分析

目的分析尺骨冠状突骨折手术治疗的必要性，评价合并有韧带损伤或桡骨头骨折的修复效果。方法2001—2004年手术治疗16例尺骨冠状突骨折患者，其中男14例，女2例；年龄18～54岁，平均36．6岁。手术中骨折复位后以螺钉或克氏针固定，同时修复前关节囊，对合并桡骨头骨折或侧副韧带损伤给予同期处理，术后功能锻炼。结果随访8～24个月，骨折临床愈合时间6～8周。平均Mayo肘关节评分80分。结论冠状突骨折需积极处理，重视软组织及韧带的检查及处理，尽量保留桡骨小头的完整性。单纯冠状突骨折手术处理后疗效较好。     

Avulsion of the medial epicondyle after ulnar collateral ligament reconstruction: imaging of a rare throwing injury

OBJECTIVE: The objective of this article is to report and describe the clinical and imaging features of an avulsion fracture of the medial epicondyle after ulnar collateral ligament (UCL) reconstruction. CONCLUSION: Avulsion fracture of the medial epicondyle is a rare complication of UCL reconstruction with distinct radiographic and MRI findings.     

Upper extremity injuries in the paediatric athlete

Injuries to the upper extremity in paediatric and adolescent athletes are increasingly being seen with expanded participation and higher competitive levels of youth sports. Injury patterns are unique to the growing musculoskeletal system and specific to the demands of the involved sport. Shoulder injuries include sternoclavicular joint injury, clavicle fracture, acromioclavicular joint injury, osteolysis of the distal clavicle, little league shoulder, proximal humerus fracture, glenohumeral instability and rotator cuff injury. Elbow injuries include supracondylar fracture, lateral condyle fracture, radial head/neck fracture, medial epicondyle avulsion, elbow dislocation and little league elbow. Wrist and hand injuries include distal radius fracture, distal radial physeal injury, triangular fibrocartilage tear, scaphoid fracture, wrist ligamentous injury thumb metacarpalphalangeal ulnar collateral ligament injury, proximal and distal interphalangeal joint injuries and finger fractures. Recognition of injury patterns with early activity modification and the initiation of efficacious treatment can prevent deformity/disability and return the youth athlete to sport.     

Elbow injuries in throwing athletes: a current concepts review

Repetitive overhead throwing imparts high valgus and extension loads to the athlete's elbow, often leading to either acute or chronic injury or progressive structural change. Tensile force is applied to the medial stabilizing structures with compression on the lateral compartment and shear stress posteriorly. Common injuries encountered in the throwing elbow include ulnar collateral ligament tears, ulnar neuritis, flexor-pronator muscle strain or tendinitis, medial epicondyle apophysitis or avulsion, valgus extension overload syndrome with olecranon osteophytes, olecranon stress fractures, osteochondritis dissecans of the capitellum, and loose bodies. Knowledge of the anatomy and function of the elbow complex, along with an understanding of throwing biomechanics, is imperative to properly diagnose and treat the throwing athlete. Recent advantages in arthroscopic surgical techniques and ligament reconstruction in the elbow have improved the prognosis for return to competition for the highly motivated athlete. However, continued overhead throwing often results in subsequent injury and symptom recurrence in the competitive athlete.     

Sonography of injury of the ulnar collateral ligament of the elbow—initial experience

Objective The purpose of this study is to describe the sonographic appearance of injuries of the ulnar collateral ligament (UCL) of the elbow.Design and patients Eight non-professional male baseball pitchers, ages 13–35 years, with medial elbow pain and clinical suspicion of ulnar collateral ligament injury, were referred for imaging. All eight underwent sonography of the affected and contralateral asymptomatic elbow, and six also underwent MR imaging. Neither valgus stress nor power Doppler was used during the sonographic examinations. Time from onset of symptoms to imaging was 1.5 weeks to 6 months. Three patients had surgical confirmation of their injuries, with time from imaging to surgery of 2 days to 9 months.Results In four patients, the UCL was ruptured, manifest sonographically in three cases as discontinuity of the normally hyperechoic ligament with anechoic fluid in the gap and in one case as non-visualization of the ligament with heterogeneous echogenicity in the expected location of the ligament. Two adolescent patients had avulsions of the UCL from the medial epicondyle, with sonographic demonstration of the avulsed echogenic bony fragment in both cases. One patient had a mild sprain, manifest as mild thickening and decreased echogenicity of the ligament sonographically compared with the contralateral normal elbow, with mild surrounding hypoechoic edema. The eighth patient had a small partial tear of the deep surface of the distal aspect of the ligament, visualized as a hypoechoic focus between the deep surface of the ligament and its ulnar attachment.Conclusion Tears of the ulnar collateral ligament are manifested sonographically as non-visualization of the ligament or alteration of the normal morphology.     

胫骨平台骨折及膝关节附属结构损伤的MRI诊断

目的评价胫骨平台骨折合并膝关节附属结构损伤的MRI表现.资料与方法 27例胫骨平台骨折病例经X线平片检查后作MRI扫描,分析不同类型胫骨平台骨折所合并的膝关节附属结构损伤的MRI形态学表现.结果 MRI能准确显示骨折所合并的膝关节附属结构的损伤性病变,包括关节软骨断裂、半月板撕裂和移位、侧副韧带和肌腱的撕裂、关节腔脂肪血性积液等,其中双髁骨折引起的损伤最为严重,撕脱骨折引起的损伤较轻.结论 MRI能准确诊断胫骨平台骨折合并的膝关节附属结构损伤,应作为膝关节外伤的常规检查手段.     

MR imaging findings of lateral ulnar collateral ligament abnormalities in patients with lateral epicondylitis.

OBJECTIVE: The purpose of this paper was to use MR imaging to determine whether a relationship exists between lateral epicondylitis and abnormalities of the lateral ulnar collateral ligament. SUBJECTS AND METHODS: The study group comprised 35 consecutive patients who were referred for MR imaging to rule out lateral epicondylitis. On MR imaging, "lateral epicondylitis" was defined as increased signal intensity of the extensor tendons close to their insertion on the lateral epicondyle. The severity of the lateral epicondylitis was graded as mild, moderate, or severe. The origin of the lateral collateral ligamentous complex was characterized, and the lateral ulnar collateral ligament was graded as normal, thickened, partially torn, or torn. Eleven patients underwent elbow surgery after the initial MR examination. RESULTS: In 15 patients, MR imaging revealed characteristics of mild lateral epicondylitis. In 13 of these patients, the lateral ulnar collateral ligament was normal; one patient showed a thickened ligament; and one patient had a thinned ligament. In 11 patients, MR imaging showed features of moderate lateral epicondylitis. In eight of these patients, the lateral ulnar collateral ligament was thickened, and in the remaining three patients the ligament was normal. All nine patients with severe lateral epicondylitis showed abnormalities of the lateral ulnar collateral ligament on MR imaging. In one of these patients the lateral ulnar collateral ligament was thickened, in three patients we saw a partial tear, and in the remaining five patients we saw a complete tear of the ligament. CONCLUSION: In our study, MR imaging features of lateral epicondylitis were often associated with thickening and tears of the lateral ulnar collateral ligament.     

Medial ulnar collateral ligament reconstruction of the elbow in throwing athletes

BACKGROUND: Medial ulnar collateral ligament insufficiency of the elbow can be a devastating injury in the throwing athlete. Reconstruction of the medial ulnar collateral ligament was initially described by Jobe and associates; good clinical results have been described after this procedure. The authors' experience with this technique raised several concerns, and thus the "docking" procedure was developed as an alternative method for medial ulnar collateral ligament reconstruction of the elbow. The early results of the docking technique were good. The authors wish to investigate the intermediate-term clinical results of this method in a large group of athletes. HYPOTHESIS: The docking technique can return overhead-throwing athletes to sport with minimal perioperative morbidity. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: During a 3-year period, 100 consecutive overhead-throwing athletes were treated with surgical reconstruction using the docking technique. The inclusion criteria were as follows: (1) a history of medial elbow pain that prevented throwing, (2) a preoperative standard noncontrast magnetic resonance image demonstrating medial ulnar collateral ligament injury, (3) clinically apparent medial ulnar collateral ligament insufficiency, and (4) an overhead-throwing athlete. At the time of surgery, all patients underwent routine arthroscopic assessment. The ulnar nerve was transposed in 22 cases. The mean follow-up was 36 months (range, 24-60 months). RESULTS: Ninety of 100 (90%) patients were able to compete at the same or a higher level than before medial ulnar collateral ligament injury for more than 12 months as noted at the follow-up interval; 7 patients were able to compete at a lower level. Only 3 patients suffered postoperative complications. CONCLUSION: The docking technique reliably returns athletes to competitive throwing with a low perioperative morbidity.     

Operative treatment of ulnar collateral ligament insufficiency of the elbow in female athletes

BACKGROUND: As women become more involved in athletic activity, injuries specific to this population also increase. No data exist regarding operative treatment of female patients with elbow instability secondary to ulnar collateral ligament insufficiency. HYPOTHESIS: Women with symptomatically unstable elbows who failed nonoperative treatment will improve after surgical intervention. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Nineteen women were retrospectively evaluated using the Andrews and Carson Elbow Outcome Score. Patients were included if they underwent repair or reconstruction of the ulnar collateral ligament for symptomatic instability that precluded them from participation in their desired sport or activities, despite nonoperative treatment. RESULTS: The mean age was 22.0 years (range, 15.1-37.2 years). The mean follow-up was 38.8 months (range, 12.4-68.6 months). Of the 19 patients, 14 were softball players, gymnasts, and tennis players. Only 1 was a pitcher. Eighteen women underwent repair by one of the following procedures: plication (n = 6), repair to bone using anchors (n = 11), or drill holes (n = 1). One patient underwent a palmaris graft reconstruction. The mean overall preoperative outcome score of 120 improved to 191 postoperatively (P < .0001). Seventeen of 18 athletes were able to return to their sport at a mean of 2.5 months postoperatively. One patient did not participate in athletics. CONCLUSION: This study demonstrated excellent overall results in 16 and good results in 3 female patients after medial elbow repair or reconstruction. Women appear to be able to consistently return to a high level of function after repair or reconstruction for medial elbow instability.     

US of the anterior bundle of the ulnar collateral ligament: findings in five cadaver elbows with MR arthrographic and anatomic comparison--initial observations

PURPOSE: To characterize the ultrasonographic (US) appearance of the anterior bundle of the ulnar collateral ligament of the elbow by comparing US images with magnetic resonance (MR) arthrograms and anatomic slices. MATERIALS AND METHODS: The ulnar collateral ligament in four cadavers (eight elbows) was blindly evaluated with US by one musculoskeletal radiologist with experience in musculoskeletal US. These results were compared with standard arthrograms, MR arthrograms, and anatomic slices by consensus reading of two musculoskeletal radiologists. The criteria for an abnormal ulnar collateral ligament included contrast material extension into the ligament or fiber discontinuity, as documented by MR arthrography and anatomic slices. RESULTS: Standard arthrography, MR arthrography, and anatomic slices demonstrated the ulnar collateral ligament to be unequivocally normal in three specimens and abnormal in two. The remaining three elbows did not meet the criteria for classification as either normal or abnormal, and thus they were excluded from the study. With US, the normal ulnar collateral ligament was fibrillar and hyperechoic between the medial epicondyle and proximal ulna. In the two abnormal cases, abnormal hypoechogenicity and ligament fiber disruption were noted. In addition, the proximal aspect of the ulnar collateral ligament varied from a cordlike structure to a broad attachment to the undersurface of the medial epicondyle with variable fat. CONCLUSION: In this small sample, the anterior bundle of the ulnar collateral ligament is identified with US by its hyperechoic and compact fibrillar echotexture. The proximal attachment of the ulnar collateral ligament has a variable appearance. Hypoechogenicity and fiber disruption indicated ulnar collateral ligament abnormality.     

Avulsion fracture of the head of the fibula (the "arcuate" sign): MR imaging findings predictive of injuries to the posterolateral ligaments and posterior cruciate ligament

OBJECTIVE: The purpose of this study was to describe the significance of an avulsion fracture of the head of the fibula ("arcuate" sign) and its association with injuries of the knee on MR imaging. MATERIALS AND METHODS: We conducted a retrospective search of 2318 patients who underwent conventional radiography and MR imaging after an episode of knee trauma. Patients were included in this study if they had an avulsion fracture of the head of the fibula revealed on conventional radiography and underwent arthroscopy. Thirteen patients, all of whom were men, satisfied the inclusion criteria. Ten patients underwent further explorative surgery. The clinical, radiographic, MR imaging, and surgical findings were then reviewed. RESULTS: The avulsion fracture of the styloid process of the fibular head was apparently related to injuries of the arcuate complex in all 13 patients. Radiographically, the bony fragment was horizontally oriented and similar in size in most patients, ranging from 8 to 10 mm in length and from 2 to 5 mm in width. On MR imaging, the fibular avulsion was identified in 11 of the 13 patients. The other two patients had marrow edema in the fibular styloid process, although the avulsion fracture was not evident. All patients had injuries of the posterior cruciate ligament (six tibial avulsions, seven midsubstance tears). No patient had a tear of the anterior cruciate ligament. Disruption of the lateral collateral ligament was evident in seven patients, and one patient had a tear of the popliteal tendon. During surgery, six patients had disruption of the arcuate complex, but this disruption could not be identified on the MR images. CONCLUSION: An avulsion fracture of the fibular head generally involves the styloid process and causes injury of some of the major stabilizers in the posterolateral corner. Avulsion fractures are strongly associated with disruption of the posterior cruciate ligament.     

Pediatric elbow fractures: MRI evaluation

Magnetic resonance imaging (MRI) was performed in eight patients under the age of 8 years who suffered elbow fractures, to assess possible fracture extension into the distal nonossified epiphysis of the humerus in seven cases and to determine the displacement and location of the radial head in one case. MRI allowed accurate depiction of the fracture line when it extended into the cartilaginous epiphysis. In four cases, MRI findings were confirmed at surgery. In five cases, surgery was obviated because no articular extension of the fracture was seen on MRI (4 cases) or because no displacement was noted (1 case). In one patient, the plain film diagnosis of a Salter type II fracture was changed to Salter type IV on the basis of the MRI findings. It is concluded that MRI might play a role in the preoperative evaluation of pediatric patients presenting with elbow trauma when extension of the fracture cannot be determined with routine radiographic studies. Elbow injuries in children may be difficult to diagnose by routine clinical and radiographic techniques [1, 4, 12, 14]. Diagnostic difficulty is due to the presence of multiple ossification centers of the distal humeral epiphysis and proximal radius and ulna; these are mostly cartilaginous until the age of 11–12 years and therefore invisible on radiographs. Following distal radial and distal tibial physeal fractures, epiphyseal elbow injuries are the most frequent epiphyseal injuries [8, 16]. These fractures tend to be unstable and often require surgical intervention. In addition, lasting sequelae such as cubitus valgus and delayed ulnar nerve palsy can occur if these fractures are not treated properly [8]. Most elbow fractures suspected to be unstable by clinical and radiographic evaluation are operated upon without additional imaging. Occasionally, arthrography or computed arthrography are used to assess epiphyseal extension and cartilaginous malignment [1, 3, 4]. Because of its ability to depict cartilage, MRI provides a noninvasive means of gaining information regarding the nonossified epiphysis. The purpose of this article is to present our preliminary experience using magnetic resonance imaging (MRI) for the detection of articular extension of elbow fractures and determination of displacement of fragments.     

肘关节后外侧旋转不稳定的解剖与生物力学研究

目的 研究肘关节外侧软组织对维持肘关节后外侧旋转稳定的作用。方法 通过解剖肘关节,观察外侧软组织的形态结构特点;将16侧上肢标本分为两组,通过生物力学试验,研究按顺序切断桡侧软组织结构时肘关节旋转度的变化。结果 肘关节伸肌起始于肱骨外髁的肌腱膜上,肌腱膜部分随肌肉走行成为肌间隔,部分止于尺骨鹰嘴外侧骨面;桡侧副韧止于尺骨冠突的部分为桡侧尺副韧带,其与桡骨环状韧带在尺度上的止点有2种类型。肘关节桡侧副韧带复合体对维持关节外侧稳定的作用约占50％,伸肌及伸肌腱膜的作用约占11％;在桡侧副韧带复合体中,桡侧副韧带（包括桡侧尺副韧带）起主要作用,桡骨环状韧带起协同作用。结论 肘关节后侧旋转不稳定除桡侧副韧带的损伤外,可能还有外侧伸肌及伸肌腱膜的损伤。     

Magnetic resonance imaging of the elbow. Part II: Abnormalities of the ligaments, tendons, and nerves

Part II of this comprehensive review on magnetic resonance imaging of the elbow discusses the role of magnetic resonance imaging in evaluating patients with abnormalities of the ligaments, tendons, and nerves of the elbow. Magnetic resonance imaging can yield high-quality multiplanar images which are useful in evaluating the soft tissue structures of the elbow. Magnetic resonance imaging can detect tears of the ulnar collateral ligament and lateral collateral ligament of the elbow with high sensitivity and specificity. Magnetic resonance imaging can determine the extent of tendon pathology in patients with medial epicondylitis and lateral epicondylitis. Magnetic resonance imaging can detect tears of the biceps tendon and triceps tendon and can distinguishing between partial and complete tendon rupture. Magnetic resonance imaging is also helpful in evaluating patients with nerve disorders at the elbow.Part I of this review can be found at: