Management of elbow instability in adults An essay submitted for partial fulfillment for Master Degree In Orthopedic surgery

Aim of the work To discuss the types of elbow instability in adults and the recent trends in its management including non-operative and operative methods.

Anatomy of the elbow joint and its stabilizers 3 separate bony articulations (distal end of the humerus, proximal ulna and the radial head). Trochogingylomoid joint (the hinged motion in flexion and extension and trochoid motion in pronation and supination).

Bony articulations of the elbow joint

Stability of the elbow provided by a ‘‘fortress’’ of static and dynamic constraints. The three primary static constraints include the ulnohumeral articulation, the anterior bundle of the medial collateral ligament (MCL), and the lateral collateral ligament (LCL) complex. Secondary constraints include the radiocapitellar articulation, the common flexor tendon, the common extensor tendon, and the capsule. Muscles that cross the elbow joint are the dynamic stabilizers

Stability of the elbow Static constrains Primary static constraints: Ulnohumeral articulation MCL (mainly anterior bundle) LCL (mainly ulnar collaterall part ) Secondary static constraints: Radiocapitellar articulation Common extensor origin Common flexor origin Dynamic constraints ( muscles around elbow joint)

Stabilizers of the elbow joint

Biomechanics of the elbow joint Range of motion: 0°-140° in extension-flexion 80° of pronation 90° of supination Variation of the flexion axis throughout range of motion is often described in terms of the screw displacement axis (SDA)

The screw displacement axis (SDA)

Pathophysiology and types of elbow instability Traumatic types A. acute elbow dislocation Simple Complex ( associated with fractures ) B. chronic Lateral elbow instability Medial elbow instability Recurrent elbow dislocation Chronic non reduced elbow dislocation Non-traumatic types Rheumatoid arthritis Connective tissue disorders Gouty arthritis

Mechanism of acute traumatic elbow dislocation Falling on outstretched hand Axial compressive force during flexion as the body approaches the ground. The body rotates internally on the elbow , a supination moment occurs at the elbow. A valgus moment results from the fact the mechanical axis is medial to the elbow.

O’Driscoll’s ring of instability It has been broken into 3 stages of disruption. Stage I involves disruption of the ulnar component of the lateral collateral ligament ( PLRI ). Stage II with continued force, disruption occurs anteriorly and posteriorly allowing for an incomplete posterolateral dislocation ( Perched ). Stage III ( Dislocated ).

O’Driscoll’s ring of instability

Complex elbow dislocation Associated radial head fracture Associated coronoid fracture Associated olecranon fracture The Monteggia lesion The terrible triad of the elbow Elbow dislocation, radial head fracture and coronoid fracture

Chronic elbow instability Chronic lateral elbow instability ( PLRI ) Patients with chronic cubitus varus caused by congenital anomaly, childhood supracondylar fracture malunion, and longstanding crutch ambulation, such as in post-polio patients. Leading to lateral static restraint overload and subsequent lateral collateral ligament disruption.

Chronic medial elbow instability results from chronic repetitive injury rather than acute injury. Commonly in throwing athletes caused by the large valgus force produced during the throwing motion (during the late cocking and early acceleration phases of throwing motion). Causing disruption of the MCL mainly the anterior bundle.

Recurrent elbow dislocation Two basic abnormalities are present: (1) the trochlear notch of the ulna is misshapen, or (2) the collateral ligaments that should stabilize the elbow are incompetent.

Chronic non reduced elbow dislocation Extensive myositis ossificans around the joint Marked shortening of the triceps muscle and medial and lateral collateral ligaments Tightening of the ulnar nerve with attempts at flexion Ossification or dense fibrous thickening of the joint capsule And extensive dense fibrous tissue filling the olecranon and coronoid fossae

Diagnosis of elbow instability In acute trauma, a detailed history of the event must be obtained. The mechanism of injury including the position of the arm at the time of the initial injury. For non acute elbow conditions, the most common complaint is pain, although stiffness or other mechanical symptoms such as locking, snapping or catching in the elbow

Special tests for instability Varus instability Varus stress test (Assessment of the integrity of the LCL): fully internally rotating the shoulder, flexing the elbow to approximately 30° to unlock the olecranon from its fossa and applying a varus stress to the elbow. If the lateral collateral ligament is deficient, the gap between the capitellum and radial head will increase.

Varus stress test

The lateral pivot shift test The patient in the supine position and with the shoulder and elbow flexed to 90°. The patient’s forearm is fully supinated, and with the examiner holding the patient’s wrist and forearm a valgus and axial compression force is applied to the elbow whilst the elbow is slowly extended. Reproduction of the patient’s symptoms and production of apprehension such that the patient prevents further movement.

The lateral pivot shift test

Push up out of a chair test The seated patient attempts to push up out of a chair with the palms facing inward on the armrests. Reproduction of symptoms constitutes a positive response

Valgus instability Valgus stress test Full external rotation of the humerus while a valgus stress is applied to the slightly flexed joint.

The milking maneuver (A) The patient applies the valgus stress to the elbow as shown with the contralateral arm. (B ) In the modified milking sign. The patient locks the humerus with the contralateral forearm; however, the examiner applies the valgus stress

The Moving Valgus Stress Test this test has been shown to be sensitive (100%) and specific (75%) for elbow pain related to UCL pathology. The shoulder is abducted and fully externally rotated to lock humeral motion. Applying a constant valgus stress as the elbow is moved through an arc of flexion and extension, noting pain between 70° and 120° of flexion

The Moving Valgus Stress Test

Radiographic Evaluation (A-P) view The distal humerus, especially the profiles of the medial and lateral epicondyles, the radial head, and the proximal ulna are highly visible in this view

laterolateral (L-L) projection The distal humerus, the olecranon process, and the anterior part of the radial head are highly visible in the lateral view

The medial oblique view It allows a better visualization of the trochlea, olecranon, and coronoid process. The radial head is obscured by the ulna

The lateral oblique view This view permits elimination of the superimposition between radius and ulna, providing a better visualization of the radial head, neck, and biceps tuberosity

The radial head-capitellum view On this view the radial head is seen without overlap by the coronoid process and an subtle fracture of the radial neck is apparent (arrow)

The axial view of the elbow It provides an excellent visualization of the olecranon, trochlea and epicondyles

CT scan CT scan of the elbow.Axial (a) and coronal reformatted CT images (b) demonstrate the linear fracture of articular surface of the radial head with a small fragment. (c) 3D reconstruction of the elbow. On A-P view (d) the fracture is not clearly visualized

Magnetic Resonance MRI of the elbow can clearly define numerous types of osseous and soft tissue pathology. Improved soft tissue contrast and numerous image planes provide advantages over CT and other imaging techniques.

Magnetic Resonance A T1-weighted SE sequence provides good evaluation of the medial and lateral epicondyles and the radiocapitellar articular surfaces

Magnetic Resonance High resolution T2-weighted GE sequence shows the normal ulnar collateral ligament (arrow) extending from the medial humeral epicondyle to the proximal ulna and normal radial collateral ligament (arrowhead)

Magnetic Resonance Oblique coronal image (3D GE) shows the radial collateral ligament (large arrow) as a linear band of signal void just deep to the extensor tendon group (small arrow)

Role of arthoscopy in diagnosis of elbow instability Diagnostic elbow arthroscopy performed as an isolated procedure for the purposes of recognizing instability is rarely, if ever, indicated. However, as a surgical adjunct performed in concert with other arthroscopic and/or open surgical procedures, arthroscopic elbow instability assessment can provide valuable information

Posterior subluxation of the radial head is seen in this same patient with posterolateral rotatory instability when the pivot shift test is applied.

Treatment of acute simple elbow dislocation Closed reduction

Mobilization recommendations For simple elbow dislocations, the elbow is immobilized for a maximum of 5 to 7 days in slightly less than 90º of flexion depending on the degree of anterior soft tissue swelling in a posterior splint. If the elbow was stable on the post reduction examination, full unprotected motion should be started no later than 1 week after injury.

Treatment of complex elbow dislocation

Operative treatment Fracture of the radial head

Fractures of the coronoid

The terrible triad of the elbow

Olecranon fractures

The Monteggia lesion

Treatment of lateral elbow instability Acute lateral ligament repair Depicting transosseous repair with a running, locking suture passed through the humeral isometric point and tied over the posterior humeral column

Ulnar lateral collateral ligament repair and reconstruction for PLRI

Treatment of medial elbow instability Classic Jobe ulnar collatereal ligament reconstruction.

The docking technique creates a humeral tunnel that accepts both limbs of the graft with tensioning performed through superior exit holes

Role of arthoscopy in treatment of elbow instability Medial instability It is indicated for those patients who maintain symptoms of posteromedial impingement despite nonoperative management

Lateral instability A, Inserting first suture through spinal needle. B, Suture in place from ulna to lateral epicondyle. C, Multiple sutures in place plicating radial ulnohumeral ligament

Application of hinged external fixator in elbow instability Compass external fixator

Treatment of recurrent elbow dislocation In these cases surgical treatment is not indicated unless dislocation recurs despite immobilization. In theses instances repair of the medial collateral ligament and other medial structures generally stabilizes the elbow

Treatment of chronic non reduced elbow dislocation The treatment options for old unreduced posterior dislocations of the elbow include closed reduction, open reduction, excision arthroplasty, interposition or replacement arthroplasty, and arthrodesis

Treatment of non-traumatic causes of elbow instability Medical treatment Physical therapy Surgical treatment Synovectomy Removal of the cysts or osteophites Arthroplasty Arthrodesis

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