Abstracts

Session 7
Elbow Imaging

Moderators : F. Handelberg, B. Stallenberg

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Ultrasound of the Elbow in Selecting Surgical Candidates

M. van Holsbeeck1, J. Introcaso2
1 Department of Diagnostic Radiology & Rehabilitation, Henry Ford Hospital, Detroit, Michigan, USA
2 Lutheran General, Chicago, IL, USA

Ultrasound enables us to distinguish patients with elbow problems who will benefit from surgery from patients who need a continuation of conservative treatment.

Lateral epicondylitis represents by far the most common symptomatic lesion in the elbow. The treatment of epicondylitis starts off with medication and physical therapy. The chronic pain of the tendinosis lacks specificity and misdiagnosis is not uncommon.

The use of ultrasound in the diagnosis of elbow pain early on when the patient first visits proves invaluable in the patients follow-up and treatment. Ultrasound may confirm the diagnosis of medial or lateral epicondylitis. This document can then be used as a baseline to judge the effects of treatment. However, the real purpose of using ultrasound in elbow pain is to exclude other diagnoses that can cause similar symptoms.

Thickened synovial folds, loose bodies, tears of collateral ligaments can ail mimic the pain and the focal tendemess caused by extensor or flexor tendon degeneration. The detection of articular pathology changes the management. Surgery is readily used when a mechanical conflict interferes with the patients elbow function. With pain as the lead symptom, we advocate ultrasound to detect:

  1. Loose Bodies (detection/localization)
  2. Ulnar and Lateral Collateral Ligament Tears
  3. Lesions of the Ulnar Nerve
  4. Retained Foreign Bodies
  5. Calcifications versus Avulsions
  6. Joint Inflammation or Infection

Joint effusion, although nonspecific, is a clear indicator of joint pathology. Cartilaginous loose bodies represent the most frequently observed joint pathology [Frankel, Radiology 1998]. Often these loose bodies will be found in the anterior, posterior or annular joint recesses. In young patients, the cause of those loose bodies will be cartilage shedding at the site of an osteochondral or chondral injury to the capitellum humeri. This osteochondral lesion has long been known as the Panner’s lesion in the elbow. Valgus alignment of the elbow puts the patient at increased risk. Panner’s disease is common in baseball pitchers and it is included in the differential diagnosis of the ‘little league elbow’. The mechanism of injury is a valgus force on the elbow causing rupture of the ulnar collateral ligament and avulsion of the medial epicondylar apophysis. Abnormal widening of the joint space at the medial aspect will be accompanied by narrowing of the lateral joint spaces. In cases of acute injury, lateral impaction on the capitellum in valgus will result in a failure of the subchondral bone of the distal humerus. The overlying cartilage may be cracked along the edges of the subchondral fracture. If the cartilage fails, the osteochondral fragment will loosen and may float freely in the synovial fluid. Cartilage derives its nutrition from surrounding joint fluid. Therefore, the free cartilage fragment may grow mto a larger loose body within the joint. This growth explains why most loose bodies do not fit their original donor site, Examination using transducer frequencies of 10 MHz and above reveals the hyaline nature of some of those loose bodies. Hyaline cartilage [Takahara, American Journal of Roentgenology 2000] can be observed at the periphery of the calcified matrix. A hyperechoic segment is typically identified associated with the hyaline cartilage. This corresponds to the portion, which has calcified or the fragment of avulsed subchondral bone. The region surrounding this linear echogenic structure will appear hypoechoic, corresponding to hyaline cartilage from the articular donor site. The ultrasound study confirms the diagnosis of intra-articular loose bodies and it facilitates the surgery. The precise localization of the loose bodies assists in choosing the correct surgical approach. It is possible to diagnose associated ulnar collateral ligament tears as well. A normal collateral ligament connects the distal humerus to the ulna and it can be found deep to the flexor origin. It is identified as a layered structure. The injuries we have found are more common at the origin, over a narrow groove in the humerus located distal, slightly posterior and deep to the medial epicondyle.

Ultrasound allows us to distinguish intraarticular from extraarticular inflammation. The study proves extremely helpful in establishing a local cause for synovitis. For example, there is no better imaging technique than ultrasound to help diagnose a foreign body located in capsule or synovium. Ultrasound may also assist in the removal of the implanted material.

Besides pain, loss of normal function of the elbow after trauma may pose another diagnostic dilemma. Radiographs maintain their importance in the initial study of an elbow dysfunction. When ultrasound is added, one can derive useful information that will guide the choice of treatment. A number of practical examples will be illustrated. Common diagnostic problems arise in differentiating : distal biceps tendonitis versus avulsion, partial versus complete triceps tendon avulsions, postero-medial impingement versus other sports related traumas, and displaced versus non-displaced lateral condyle fractures.

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Imaging of the Elbow
An Update

M. Schenk, M.K. Dalinka
Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, PA, USA

The elbow has received considerably less attention in the MR literature than the more commonly imaged shoulder and knee. It is a complex joint which acts as a link between the shoulder and the hand enhancing the flexibility of hand motion and transmiting generated forces. The elbow is vulnerable to a variety of injuries both acute and chronic. MR is particularly useful in the evaluation of chronic elbow pain which is often secondary to chronic overuse.

Routine radiographs and CT are excellent for evaluating the osseous structures and detecting fluid, calcification or ossification in and about the joint. Detailed examination of the soft tissues is better performed with MRI.

MR has a major use in the treatment planning of bone and soft tissue neoplasms and is helpful in detecting osseous lesions such as marrow edema or occult fractures. The accurate evaluation of the complex anatomy of the elbow requires optimization of MR imaging techniques including imaging parameters and positioning. Familiarity with the anatomy and signal characteristics are essential in the detection of subtle abnormalities and early or minimal pathologic findings.

Normal Anatomy - The elbow is a hinge joint with three articulations : the humeral-radial, humeral-ulnar and radioulnar. Flexion and extension occur at the humeroulna articulation and pronation supination at the radiocapitellar joint. The relationship between the humerus, radius and ulna are best evaluated in the coronal and sagittal planes and the radial ulna articulation can be evaluated best with axial images.

The muscles about the elbow can be divided into four compartments dependent upon their location. The muscles in the anterior compartment consist of the brachialis and the biceps muscles. The brachialis muscle arises from the anterior inferior humerus and crosses the elbow joint to insert in the ulnar just distal to the coronoid process. In the region of the elbow the two heads of the biceps brachialis have already converge to form the biceps tendon which is superficial to the brachialis muscle and crosses the elbow joint to insert into the radial tuberosity.

The posterior compartment contains the triceps muscle which at the elbow has already fused into a single musculotendinous unit that inserts into the posterior superior olecranon and the anconeus, a small fan shaped muscle arising from the posterior medial epicondyle and inserting into the posterior lateral aspect of the olecranon.

The flexors of the hand and wrist, pronator teres and the palmaris longus are the muscles in the medial compartment. The pronator teres muscle is the most anterior and it arises from the humerus proximal to the medial epicondyle and the common tendon of the other flexor muscles. Its deep portion arises from the proximal ulna. The flexor muscles arise from a common tendon. The muscles from anterior to posterior consist of the flexor carpi radialis, palmaris longus, flexor carpi ulnaris and the flexor digitorum superficialis. These muscles are often difficult to separate in the region of the elbow.

The lateral compartment of the elbow contains the supinator muscle, the extensor muscles of the digits and wrist and the brachioradialis. The supinator muscle arises from the posterior-lateral aspect of the ulna and wraps around the lateral aspect of the radius. It is easy to identify in all imaging planes. The brachioradialis is the most anterior of the lateral muscles and is difficult to separate from the other muscles in the extensor compartment. The other muscles are the extensor carpi radialis longus, the extensor carpi radialis brevis, the extensor digitorum, extensor digiti minimi and extensor carpi ulnaris.

The ligaments about the elbow are divided into medial and lateral ligamentous complexes. They are black on all spin echo pulse sequences and best delineated on oblique coronal views. The medial collateral ligament (MCL) complex is composed of anterior and posterior bundles and a transverse bundle. The functionally important anterior bundle is routinely visualized on MR; it is taut with the elbow extended and is best seen on oblique coronal images. The anterior bundle arises from the inferior aspect of the medial epicondyle and inserts on the medial margin of the coronoid process. More proximally the anterior fibers have a fan-like origin from the medial epicondyle. A synovial invagination is commonly seen adjacent to the MCL and is of intermediate or high signal intensity adjacent to the low signal intensity MCL.

The lateral collateral ligament (LCL) complex is composed primarily of the radial collateral ligament (RCL), the annular ligament and the lateral ulnar collateral ligament (LUCL). The radial collateral ligament arises from the lateral epicondyle and inserts directly onto the annular ligament. The LUCL arises from the lateral epicondyle but crosses posterior to the radius and inserts on the crista supinatoris of the ulna, distal to the insertion of the annular ligament. The LCUL is only seen occasionally and is best imaged with oblique coronal images. The annular ligament surrounds the radial head and inserts with the LUCL on the sigmoid notch of the ulna; it is best seen on axial images.

The nerves about the elbow consist of the ulnar, median and radial nerves. The ulnar nerve can be consistently identified as a round dot of intermediate signal intensity surrounded by perineural fat. It crosses posterior to the medial epicondyle and runs within the fibro-osseous cubital tunnel. The roof of the cubital tunnel is formed proximally by the cubital tunnel retinaculum which extends from the medial epicondyle to the olecranon and distally to the flexor carpi ulnaris aponeurosis (arcuate ligament). The nerve extends between the humeral and ulnar heads of the flexor carpi ulnaris distal to the elbow joint.

Lateral epicondylitis - Lateral epicondylitis is the most common source of elbow pain in the general population. This is often referred to as tennis elbow as it occurs in middle aged recreational tennis players. Although it is referred to as "epicondylitis", it really represents degeneration and tearing of the common extensor tendon rather than an inflammatory change. The histologic findings are those of fibrillar degeneration, hyaline and myxoid degeneration, and angiofibroblastic proliferation without acute or chronic inflammation. When inflammation is present, it is usually limited to the fibrous sheath surrounding the tendon, i.e. the peritenon. The vast majority of patients with this disorder respond to conservative therapy but approximately 5-10% are recalcitrant and may require surgical intervention. In approximately 20% of patients plain radiographs are abnormal with a spur at the lateral epicondyle or calcification in the common extensor tendon.

MR may be helpful in patients with recalcitrant symptoms as it can assess the site and degree of tendon damage (degeneration vs. partial or complete tear), identify potential concurrent abnormalities and exclude other potential causes of persistent lateral elbow pain i.e. radiocapitellar degenerative arthrosis, radial nerve entrapment, posterolateral instability, or synovitis. Intratendinous calcification is more difficult to recognize on MR than plain film although it is may be apparent on gradient echo sequences.

The morphology and signal intensity of the common extensor tendon must be critically evaluated on all imaging sequences. Degenerations and tears primarily involve the extensor carpi radialis brevis tendon and occasionally the extensor digitorum communis tendon. The normal tendon is devoid of signal on all pulse sequences, smooth in contour and without focal thinning or enlargement. Increased or intermediate signal on T1 weighted sequences or morphlogical abnormalities are indications of an abnormal tendon. The T2 weighted images are used to distinguish between tendon degeneration and tendon tearing. With partial or complete tears there is a focal area of discontinuity within the tendon filled with high signal (fluid) on the T2 weighted images. With complete tears there is full thickness discontinuity with a gap between the tendon and epicondyle. In tendons which are degenerated, intermediate signal on T1 weighted images often decreases or stays the same with T2 weighting. It may be difficult to distinguish between severe degeneration and partial tears or high grade partial tears and complete tears as tendon pathology represents a continuum beginning with tendon degeneration and ending with tears. In one study increased signal in the anconeus muscle accompanied all seven patients with chronic lateral epicondylitis.

Peritendinitis (peritonitis) can be recognized when fluid surrounds the tendon. The injection of steroids may give rise to high signal intensity which can be falsely interpreted as peritendinous and or muscle edema. Local steroids may also increase the risk of tendon rupture.

Lateral Collateral Ligament Injury - Insufficiency of the lateral ulnar collateral ligament may lead to recurrent posterior lateral instability of the elbow. This most commonly occurs as a result of elbow dislocation but can be seen following tennis elbow surgery. The patient often presents with symptoms of lateral elbow pain or instability. The lateral collateral ligament is best seen on oblique coronal views but is inconsistently visualized on routine examinations. As with other ligament and tendon, tears are diagnosed by fiber disruption.

Medial Epicondylitis - Medial epicondylitis is considerably less common than its lateral counterpart. It has been referred to as medial tennis elbow, golfer's elbow and pitcher’s elbow. As with the lateral epicondyle the pathologic lesion represents degeneration as a result of chronic repetitive stress and the vast majority of patients respond to conservative treatment.

Repetitive valgus stress in overhead or throwing sports can result in injury not only to the common flexor tendon but to the other soft tissue structures about the medial aspect of the elbow including the ulnar nerve and the medial collateral ligament. Ulnar nerve injury occurs in up to 50% of patients operated on for medial epicondylitis. In the throwing athlete, medial collateral ligament insufficiency may be present as well.

It is difficult to differentiate and separate the various causes of chronic medial elbow pain. MR is helpful in confirming the diagnosis of medial tendon degeneration (epicondylitis), grading the degree of tendon injury and evaluating the status of the medial collateral ligament and adjacent ulnar nerve.

Medial Collateral Ligament Injury - Medial collateral ligament is essential for elbow stability which is dependent upon the combination of articular congruence and ligamentous as restraint. The anterior bundle of the MCL is the primary medial constraint for elbow stability. Injury to this structure can result in valgus instability particularly in athletes involved in overhead, racket or throwing sports. Although injury may occur acutely, (typically in javelin throwers or baseball pitchers), it is commonly a result of chronic microtrauma from repetitive valgus stress. A combination of pathologic changes often occur in the elbow secondary to valgus instability. These include medial tendon degeneration, ulnar traction neuropathy, posteromedial olecranon impingement and radiocapitellar overload. Impingement by the olecranon on the medial wall of the olecranon fossa can result in posteromedial osteophytes and loose bodies and the osteophytes may compress the ulnar nerve. Lateral compression overload can result in osteochondral fractures (osteochondritis dissecans) of the capitellum or degenerative arthrosis of the radiocapitellar joint.

The imaging evaluation begins with standard radiography. Occasionally one can identify an avulsion fracture of the medial epicondyle. With more chronic injuries routine radiographs may identify calcification within the anterior bundle of the MCL, osteophytes arising from the posteromedial olecranon, loose bodies in the posterior compartment, or osteochondritic lesions of the capitellum. Medial collateral ligament tears of the elbow can be demonstrated with MR or CT arthrography. MR is not invasive and provides a more global examination of the elbow which can assess other or associated causes of elbow pain. Arthrography may be less sensitive in the setting of chronic tears. MR arthrography has also been utilized in the detection of partial ligament tears.

On MR, attention to the positioning and technical factors is critical as the structures are small and the ulnar collateral ligament runs obliquely. The anterior bundle of the MCL is normally visualized in the oblique coronal plane on thin section or three dimensional gradient echo images. Injury to the ligament may be partial or complete. In the acute stage there may be high signal in the periligamentous tissues representing edema or hemorrhage and lateral compartment bone contusions (marrow edema) may be seen as a result of impaction injury from valgus stress. Marrow edema is best appreciated on fat suppressed images such as STIR or T2 weighted images with chemical saturation. An intact ligament with surrounding signal suggest a sprain. With chronic degeneration, the ligament appears intact, but thickened. Although full thickness tears of the MCL are accurately identified on magnetic resonance imaging, partial thickness tears are less consistently diagnosed. Partial thickness tears usually occur at the ulnar insertion but partial tears of the humeral insertion site can also cause symptomatic valgus instability, particularly in the throwing athlete.

CT or MR arthrography enhances the visualization of partial undersurface tears. Schwartz diagnosed six of seven surgical-confirmed partial tears by MR arthrography and Timmerman identified five of seven by CT arthrography. The anterior bundle of the MCL inserts at the proximal medial aspect of the coronoid process; partial tears are diagnosed when contrast extends along a medial margin of the process but does not leak into the medial soft tissues. The intact superficial fibers contain the fluid within the capsule which has been referred to as the "T" sign.

Nerve Injury and Entrapment - The ulnar nerve is the most frequently injured nerve about the elbow. Injuries may occur secondary to nerve traction or compression, subluxation or direct trauma. Etiologies also include malunited fractures of the medial epicondyle, thickened cubital tunnel retinaculum, anomalous anconeus epitrochlearis muscle or masses in the cubital tunnel. Signs of ulnar neuropathy may be present in more than 40% of throwing athletes with valgus instability or medial collateral injury. The retinaculum about the cubital tunnel is absent in approximately 10% of the population; this may cause subluxation of the ulnar nerve and may be associated with symptoms of friction neuritis. The nerve may sublux anterior to the medial epicondyle or remain posterior and lateral to the epicondylar groove.

Electrodiagnostic studies are often unable to demonstrate injury to the ulnar nerve at the elbow. MRI enables one to determine the course and identification of the potential sources of ulnar nerve compression. MR features of ulnar neuropathy include nerve displacement, focal or fusiform nerve enlargement and increased signal intensity. The normal nerve is normally of intermediate signal on T2 weighted images, isointense or slightly higher in signal than muscle.

Osteochondrosis and Osteochondritis Dissecans - Osteochondrosis of the capitellum, i.e. Panner’s disease, is a benign, self limited abnormality typically occurring in males between the ages of 7-12 (prior to complete ossification of the capitellum). This abnormality represents an alteration of endochondral ossification of the epiphyses which is usually benign, with eventual radiographic return to normal. Patients typically present with pain, tenderness and loss of extension and radiographs reveal motteled appearing epiphyses which may appear fragmented. On MRI, the ossified epiphysis is decreased in signal intensity on T1 weighted images.

Osteochondritis dissecans (OCD) is a lesion of bone and cartilage which typically involves the anterior aspect of the capitellum in young adolescents (10-16 year olds). The majority of cases occur in the dominant extremity of baseball players or gymnasts and are thought to result from repetitive microtrauma with chronic impaction and superimposed vascular ischemia. The area of involvment contains subchondral bone and cartilage which may remain in situ, heal, or undergo fragmentation leading to loose body formation and eventually resulting in degenerative joint disease. Routine radiography may depict the defect in the capitellum with or without loose body formation. There may be a localized area of subchondral lucency. In some cases the plain films may be normal or the abnormality subtle.

MR may aid in the detection of subtle abnormalities including surrounding edema. MR arthrography may be used to improve the detection of articular cartilage abnormalities. With MR arthrography contrast may extend through the cartilage into the subchondral bone and surround a nondisplaced osteochondral fragment. The contrast may also aid in the identification and localization of loose bodies. This may be seen with standard MR of the elbow in the presence of effusion.

Osteochondritis dissecans should not be confused with the pseudodefect of the capitellum, a normal anatomic finding. This pseudodefect represents a trough at the junction of the nonarticular portion of the lateral condyle and the posterolateral cartilage covered capitellum. It is seen on sagittal and coronal images and is more conspicuous when joint fluid is present. This pseudodefect is characteristically located posteriorly while OCD is present anteriorly. In addition the adjacent bone is normal in signal in patients with the pseudodefect and may be abnormal in patients with osteochondritis dissecans.

Biceps Tendon Injury - Although most injuries to the biceps tendon occur in the shoulder, injury to the distal tendon is being reported with increased frequency following the advent of MRI.

Injury to the distal biceps tendon often occurs in the dominant hand of middle aged males, with weightlifters presenting at a younger age. The injury is usually secondary to acute trauma with forced hyperextension of the elbow in midflexion . This leads to complete avulsion of the tendon from its insertion site on the radial tuberosity. Partial tendon tears and tears of the myotendinous junction are much less common. Although often clinically apparent, partial tears, complete nonretracted tears, and chronic tears may be more difficult to diagnose. Chronic anterior elbow pain may be caused by degeneration of the distal biceps tendon or radial bicipital bursitis. These two entities can coexist.

MRI can diagnose bicipital tendon degeneration, radial bicipital bursitis, and complete biceps tendon tears. MR is helpful in determining the degree of tendon retraction. It is important to image the biceps tendon from the myotendinous junction to its insertion on the radial tuberosity of the ulna. The T2 weighted images are best for determining the degree and site of the tear. Sagittal images are helpful for determining the degree of tendon retraction. With chronic tears, the tendon may be retracted into the substance of the muscle itself. Radial bicipital bursitis may be identified by detecting a fluid collection between the biceps tendon and the radial tuberosity. This bursa can become quite large and may simulate a soft tissue tumor. Contrast enhancement may aid in this differentiation as the central fluid collection will not enhance with gadolinium.

Muscle Injury - Muscle injuries are common and can be detected and characterized on MRI although imaging is not usually necessary. On occasion, in high performance athletes or patients with chronic symptoms, an MRI may be performed.

Muscle strains are usually secondary to indirect forces and commonly occur in muscles which cross two joints such as the biceps muscle. Muscle contusions usually cause injury at the site of the injury. Occasionally severe contusions may result in myositis ossificans. The MR findings depend upon the degree of fiber disruption. A grade I injury is manifested by edema often with microscopic tears. A grade II injury is a partial tear at the myotendinous junction and a grade III injury represents a complete tear. Muscle injuries are best demonstrated by fat suppressed sequences such as STIR and chemical saturation.

Fractures - MR is rarely utilized in the diagnosis of fractures. However in a difficult or questionable case, MR is highly diagnostic. This is particularly true in the pediatric age group when fractures may occur through the cartilaginous epiphysis, prior to ossification of the growth centers. In this age group sedation is often required for the examination.

Lateral condylar fractures account for approximately 10-15% of elbow fractures in children. They are usually Salter-Harris IV fractures and are intra-articular and transphyseal. The intraarticular portion of the fracture is purely cartilaginous and not visible on standard radiography which makes it difficult to differentiate from a Salter-Harris type II injury. Extension of the fracture through the unossified cartilage can be seen by standard MR or with MR arthrography.

Evaluation of avulsion fractures of the medial epicondyle in children may be difficult, particularly if there is limited epiphyseal ossification. The injury is usually a Salter-Harris type I fracture with the epicondyle either pulled inferiority or displaced into the joint. MR can determine the location and degree of displacement of the unossified epiphysis.

Loose Bodies - The elbow is the second most common site of loose bodies. These loose bodies may be the results of degenerative joint disease, osteochondritis dissecans or proliferative disorders of the synovium. In patients with valgus instabilities, loose bodies may form in the posterior aspect of the olecranon fossa secondary to posteromedial olecranon impingement.

Routine radiographs can often identify ossified loose bodies. However, it may be difficult to distinguish them from osteophytes or extraarticular calcifications and plain radiographs will not detect cartilaginous loose bodies. CT arthrography or MR arthrography can accurately identify most loose bodies and determine their location. They may however be difficult to differentiate from osteophytes or hypertrophied synovium. MR has the advantage of multiplanar imaging.

Addendum, abstract book

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Arthro CT or MRI in Evaluation of Cartilaginous Lesions of the Elbow.
Experimental Study

C. Debouck1, J. Alexiou2, Th. Mettens3, B. Stallenberg4, M. Rooze1
1 Department of Human and Embryology, Faculty of Medicine, University of Brussels
2 Department of Radiology, New Paul Brien Institut
3 Faculté des Sciences Appliquées, Service des Systèmes Logiques et Numériques, Université libre de Bruxelles, Brussels, Belgium
4 Department of Radiology, Erasme University Hospital

Purpose - To compare relative performances of CT-arthrography and MRI in the evaluation of humero-radial cartilage lesions.

Material and methods - 20 elbow joints from cadaveric specimens were examined at both CT and MR and afterwards macroscopically. 1.2 mm CT coronal sections and 0.8 mm sagittal MR sections were acquired. Detection, location and grading of the lesions (0: intact cartilage, 1: partial ulceration, 2: exposed bone) were evaluated using the macroscopic results as a standard of reference.

For the radial head a subdivision in 8 sectors was defined relatively to the orientation of the radial tuberosity. The capitulum was divided into 4 antero-posterior sectors and into 3 parts in the lateral direction.

Results - For the detection of the lesions according to the surface examined, the sensitivity was 100% for CT and 50-100% for MR imaging and the specificity was 93-100% for both CT and MR techniques. The location of the lesions was correct in 84.4% for CT and in 56.2% for MR technique. Concerning the grading of the lesions, 12.5% were overestimated at CT and 37.5% were underestimated at MR imaging.

Conclusion - Both techniques were found to be accurate means for characterizatrion of humero-radial cartilage lesions, CT-arthrography being slightly superior but invasive. MR imaging needs further evaluation in patients.

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Arthroscopy and Radial Head Fractures

F. Handelberg
AZ VUB Brussels, Belgium

Building on our experience with the arthroscopic assessment and treatment of tibial plateau fractures, we decided to perform arthroscopy in selected cases of radial head fractures. It soon became obvious that only isolated and noncomminuted fractures of type B2 in the AO classification came into consideration for this approach. Since standard radiographs of the elbow do not always show precisely if two, three or more fragments are present, and as we frequently were surprised by the comminution while performing open surgery, we think that a preoperative CT-scan is mandatory. Based on this CT-scan, simple fractures of type B2.1 and B2.2 were chosen for the arthroscopic approach.

Technique - The patient is positioned in ventral decubitus, with the arm hanging freely over an armrest, so that an assistant can provide flexion-extension and pronation-supination. The tourniquet is inflated to 300 mm Hg.

The arthroscope is inserted through the soft spot directly lateral to the olecranon and in the humero-radial joint line, with the arm slightly extended, and directed to the tip of the olecranon. We generally use a pump with a pressure set to 50 mm Hg maximally; back flow comes through a spinal needle placed either in a superior position (olecranon fossa) or directly lateral. Once the hemarthrosis is rinsed out, the radial head can be easily inspected. Through a 5-mm lateral stab wound, a thin probe is inserted to reduce the bony fragments. Optionally, the fracture is temporarily stabilized with a small Kirschner wire. It is then definitively fixed with a small fragment AO screw of 2 mm or a cannulated Herbert screw. Stability and reduction can be assessed easily by direct vision, but positioning and especially the length of the screw is preferably observed by fluoroscopy, since protrusion cannot be seen arthroscopically. A plaster splint is applied for 24 hours, then early active assisted mobilization is started in both flexion-extension and pronation-supination.

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Surgical Repair of Acute Traumatic Closed Transection of the Biceps Brachii in Paratroopers

J.F. Kragh, C.J. Basamania, K.D. Harvey
 Orthopedic Service, Department of Orthopedics and Rehabilitation, Womack Army Medical Center, Fort Bragg, NC

Introduction - Direct muscle trauma is common, but studies of repair of belly transections are rare. Controversy exists whether muscles are repairable when no tendon is involved.

Methods - The authors conducted a prospective, controlled study of surgical repairs of acute traumatic closed transection of the biceps brachii muscle bellies in paratroopers. Illustrations detail suturing muscle fibers and epimysium using running interlocking and modified Mason-Allen stitches. Nine patients had muscle-to-muscle tissue repairs, and their uninjured arms served as internal controls. Patients with complete transections served as external controls. The imaging protocol included obtaining biceps muscle MRIs with an open or felx coil. We imaged sagittal T1 4mm sections with 0.5 mm skips at a 192 by 256 matrix. We did axial fast spin echo T2 fat saturation 5 mm sections with 2 mm skips, an ETL 6, and a 256 by 256 matrix. We did sagittal fast spin echo T2 fat saturation 4 mm sections with 0.5 mm skips, an ETL 6, and a 256 by 256 matrix. The FSE T2 was about 3000TR and 80 TE. Ultrasounds were also obtained if MRI was not available (once) or for comparison with MRI (twice) or postoperative for interest (once).

Results - In the surgery group, follow-up averaged 0.6 year (0.1 - 1.14 year). In the complete conservative group, follow-up averaged 10.1 years (1.9 - 15.2 years). In the incomplete group, follow-up averaged 2.1 years (1.7 - 3.0 years). Comparing surgery to the complete conservative group, range of motion, muscle size, and work capacity were the same and normal (p<0.05). The surgery group had better appearance (Likert scale 4.6/5 vs. 3.0/5, p=0.000002), supination power (60 inch-pounds vs. 51 inch-pounds, p=0.049), and satisfaction (100% excellent vs. 100% satisfactory). The complete conservative group had a persistent 40% deficit of supination strength compared to their uninjured arms. This is the same deficit found in untreated distal biceps tendon ruptures. The incomplete group had no subjective problems or objective impairments.

Analysis - This is the first human study to show specifically how to repair a muscle belly transection and the first to image in surgically-confirmed complete vs. incomplete transection. It is also the first to report imaging of muscle belly transection or laceration. We also have nearly the longest muscle repair follow-up. Our conservatively treated patients did rather well also, but our repair patients did better.

Discussion - Surgical repair of biceps muscle belly transection can lead to excellent functional results in a high-demand population.

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