Lateral Elbow Instability Travis Marion, MD. MSc. BEd. Academic Half Day Apr 2012

Outline Intro – definitions Anatomy Biomechanics Evaluation Mechanism of injury Acute  Terrible Triad Fracture classification Management Reconstruction Priniciples Outcomes Chronic  PRLI

Anatomy

Anatomy Proximal Ulna Greater sigmoid notch Lesser sigmoid notch Sublime tubercle Coronoid process Greater sigmoid notch articulates with the trochlea Lesser articulates with the radial head forming the radioulnar joint Coronoid process serves as an important anterior and varus buttress

Anatomy Troclear notch provides nearly 180º of capture with posterior 30º tilt Central ridge interdigitates with groove further enhancing stability

Anatomy Coronoid Process Tip Body Anterolateral facet Anteromedial facet 6mm from capsule 12mm from brachialis 18mm from MCL No soft tissue structures routinely attach

Anatomy Radial Head Articulates Safe Zone2 Capitellum Radial notch Radial head articular dish and margin covered by articular cartilage Forearm in neutral lateral portion of articular surface devoid of cartilage, does not articulate with capitellum or proximal ulna, important for planning fixation

Anatomy MCL21 Anterior bundle Posterior bundle Transverse Anterior bundle originates anterior inferior aspect of the medial epicondyle, inserts on the sublime

Anatomy LCL19,20 RCL LUCL Accessory lateral collateral Annular LCL – attaches to the lateral epicondyle and fans out to merge indistinguishably with the annular ligament LUCL – a thickening of the capsule, from isometric point on lat epicondyle, inserting on the supinator crest. Serves as lateral stabilizer (tight in varus) and posterior buttress for the radial head. RCL inserts on the annular ALCL – stabilizes the annular ligament during varus stress

Biomechanics

Biomechanics Primary Stabilizers Secondary Stabilizers Ulnohumeral articulation3 MCL LCL complex4 Secondary Stabilizers Radial capitellar4, 30 Joint capsule Common flexor/pronator and extensors Compressive force Anconeus, triceps and bracialis Rotatory stabilizer ECU, EDM Ulnohumeral resists anterior-posterior compressive forces Coronoid beyond 30 degrees of flexion more than 50% resistance to posterior subluxation Biomechanical studies have shown importance for axial, varus, posterior medial and lateral rotatory forces MCL important for valgus and posteromedial stability, anterior band of primary importance LCL varus and posterolateral rotatory instability – cadaveric study demonstrated that an isolated removal of the LCL resulted in mean posterolateral rotatory laxity of 33º from 5.4º Radial capitellar – secondary valgus stabilizer and compressive loads – cadaveric study demonstrated 9.6º posterolateral rotatory laxity in isolated radial head resections (represented a doubling of laxity) post traumatic excision revealed reduced arc flexion (mean 103º), 5/7 perceived instability, 100% reported weakness, and all had positive pivot shift)

Evaluation

Evaluation History Physical Physical Closed reduction Imaging Chronic Severity Mechanism Precipitants Chonic Inciting event Clicking/snapping/clunking/locking Apprehensive maneuver Past medical history Physical Acute Inspection Open vs closed Alignment Joint above and below Detailed neurologic Physical Chronic Full pain free ROM Pain free stressing Special tests Closed reduction Imaging Radiographs pre/post reduction AP/Lat/Oblique CT History Events severity and mechanism – Young high energy with more ligamentous and osseous disruption vs elderly low energy only ligamentous Mechanism allows surgeon to predict injured structures Precipitants of fall/instability – progressive reduction in required amount of force, reduction movements clicking/locking/clunking/locking typically in extension half of arc and in supination Apprehensive maneuver – push off when getting out of a chair - Past medical history – generalized ligamentous laxity or varus inclinations of the distal humerus secondary to pediatric SC #’s Physical Imaging - Line through the radial head should intersect the centre of the capitellum regardless of projection

Instability Classification

Classification18 Timing (acute, chronic or recurrent) Articulations (elbow vs radial head vs both) Direction of displacement (valgus, varus, anterior, posterolateral rotatory) Degree of displacement (subluxation or dislocation) – see slide 18 Simple or complex 2) Elbow – most common category of elbow instability involving the hinge joint Radioulnar – usually traumatic and associated with monteggia Elbow and prox radioulnar 3) Posterolateral rotatory most common

Mechanism

Mechanism of Injury FOOSH, elbow extended Posteriorly directed force3 Ulna levers out of trochlea Valgus stress/posterolateral roll out/supination6 Capsuloligamentous failure lateral to medial, MCL anterior bundle last to rupture6 Radial head, coronoid fx Valgus force created as the mechanical axis passes through the lateral side of the joint/body rotates internally on the elbow Supination movement pushes the coronoid beneath the trochlea/alternatively fracture requiring less external rotatin Conceivable that can dislocate without MCL rupture

Mechanism 0 – reduced 1 - PRLI – posterolateral rotatory instability – first described by O`Driscoll et al, JBJS 1991 2- perched – incomplete, supination allowing the coronoid to traverse inferiorly 3 - dislocation

Mechanism Stage 1 lateral disruption (PRLI) Failure of posterolateral capsular ligaments initial event LUCL – originally thought to be primary stabilizer Anatomic study 1997 suggested primary lateral stabilizer combination LCL and annular ligament ECU and extensor digiti minimi secondary rotatory stabilizers One histologic study that refutes LUCL as a primary stabilizer and is a mere capsular thickening (1999) Dunning et al, 2001 demonstrated with annular intact the LCL or LUCL could be transected, in a cadaveric study whereby structures were sequentially sectioned Concensus that LCL complex combined contributes as the primary stabilizer, most dislocations as force generated across the joint the LCL and casp Stage 2 anterior and posterior capsular disruption – perched Stage 3 medial disruption, 3A partial disruption (MCL intact), 3B complete disruption (unstable to valgus, immobilize 30-45º of flexion), 3C (entire distal humerus stripped of soft tissue – stable only at 90º) Each stage of injury elicits different physical findings

Acute Traumatic Instability

Classification Simple Dislocations Complex Dislocations Capsuloligamentous injury No osseous injury Complex Dislocations Associated osseous injury

Patterns of Fracture Dislocation Terrible Triad Posterior dislocation of radial head Varus posteromedial rotatory instability Anterior olecranon fracture dislocations Will only discuss terrible triad

Fracture Classification Mason Classification I. non displaced II. Displaced partial articular III. Multifragmentary IV. Described in 1962 by Johnson indicates associated ulnohumeral dislocation Morrey Modified Classification Include radial neck fractures Quantify definition of displacement  fragments >30% with 2mm Include dislocation

Fracture Classification Regan and Morrey7 O`Driscoll8 Fracture Classification Regan and Morrey Tip - avulsion ≤ 50% > 50%

Fracture Classification O`Driscoll Tip – do not pass the sublime tubercle Subtype I – less than 2mm Subtype II – more than 2mm and largely associated with triad injuries Anteromedial Subtype I – medial to tip to anterior of the sublime tubercle Subtype II – extend to sublime tubercle with extension to the tip Subtype III – anteromedial rim and entire sublime tubercle with/without tip Base Anteromedial fractures do not occur with the same posterolateral rotatory instability rather the opposite. Axial force in combination with posteromedial rotation, varus force, and elbow flexion causing the medial trochlea to abut the anteromedial facet of the coronoid. Involves disruption of the LCL if no associated olcranon fracture

Traumatic Instability Terrible Triad1 Elbow dislocation Coronoid fracture Radial head fracture

Management Follows the nature of the injury – lateral to medial

Management Nonsurgical Concentrically reduced ulnohumeral and radiocapitellar Stable to allow sufficient ROM (extension to 30°) Congruency evaluated under fluoroscopically CT evaluation Radial head fx minimally reduced with no mechanical block Type I coronoid fracture Tx as simple dislocation Splint at 90° Isometric biceps/triceps

Management Surgical Incision Advantages Posterior Access to medial and lateral Precludes requirement for secondary incision Reduced injury to cutaneous inervation9 Improved cosmesis Disadvanages Large flaps

Management Kocher EDC split Anconeus (radial) ECU (PIN) Kocher/EDC both allow access to the radial head and LCL

Management No Replacement Pros Cons No healing required Exposure to coronoid Faster recovery Cons Non anatomic Overstuffing Stiffness Management of radial head fractures as per Hotchkiss: Think Mason Classification Do nothing Fix Replace

Management Yes ORIF Pros Cons Anatomic No overstuffing Non union Malunion Implant complications PIN palsy Fix – no neck fracture, Minifrag, headless screws to avoid clicking

Management Yes No One less incision Medial approach No ulnar nerve dissection Amenable to ORIF vs suture technique Use targeting devices to aid in fixation positioning Medial approach Hotchkiss Can address trochlear fractures Ulnar nerve dissection May address MCL if warranted Can perform a taylor if require humeral reduction/fixation The brachial fascia is incised along the anterior aspect of the septum, and the flexor-pronator group is released from the supracondylar ridge. The flexor group is split longitudinally at the distal aspect, taking care to leave the posterior aspect of the FCU origin intact on the medial aspect of the distal humerus. The brachialis, flexor carpi radialis, and pronator teres muscles are elevated off the anterior capsule. Sufficient elevation of these muscles makes it possible to see across to the lateral aspect of the anterior elbow joint. A cuff of tissue may be left on the ridge so that the muscle group can be repaired at the end of the procedure.

Management LCL Repair Origin at isometric point on lateral epicondyle Suture anchors vs bone tunnels Check anatomy Check stability If unstable repair the MCL Persistent instability = external fixator Typically torn at origin, bare lateral epicondyle Check the reconstructed anatomy under fluoroscopy If persistent instability and appropriate reconn, Repair MCL

Reconstruction Principles < 10% coronoid fractures little effect on stability5 MCL repair more effective than coronoid repair5 Most triads involve more than 10% MCL most important valgus stabilizer Requires radial head Radial head acts as buttress Radial head tensions LCL providing varus stability In biomechanical cadaveric studies, MCL more important than coronoid if less than 10% in setting of triad

Outcomes Pugh and McKee, 2002 Pugh et al, JBJS AM, 2004 Mean arc 20º and 135º Mean rotation 135º Delay in treatment or revision 20% greater loss of motion 25% revision Pugh et al, JBJS AM, 2004 36 patients, multicentred 112º flexion arc 136º rotation 15 excellent, 13 good, 7 fair, 1 poor 8 revisions (synostosis, instability, contracture release, wound infection) Prolonged immobilization worse prognosis No defined length of immobilization resulting in poorer outcomes. Previous studies more than 4 weeks led to instability. Better to manage a stiff congruent elbow vs mobile incongruent

Outcomes Frothman et al, J Hand Surgery, 2007 Similar Findings 30 patients 117º flexion arc Rotation 135º 77% excellent results Single surgeon, no MCL repairs Similar Findings Chemama et al, Orthop Traumatol Surg Res, 2010 Rodriguez-Martin et al, Int Orthop, 2011 Jeong et al, J Orthop Sci, 2010 Lindenhovius et al, J Hand Surgery 2008 Acute within 2 weeks (ave 6 days) vs subacute repair > 3 weeks (ave 7 weeks) No difference except 20º more flexion arc

Chronic Instability

Posterolateral Rotatory Instability Most common type of symptomatic instability First described 1991 Recurrent proximal radio-ulnar displacement Prox radius and ulna rotate externally in relation to the humerus Radioulnar joint intact and rotates as a single unit as opposed to isolated radial head dislocation Lateral elbow instability with an absence of physical findings

PRLI Failure of LCL complex Physical exam Trauma iatrogenic chronic attenuation29 Physical exam PRLI - analogous to pivot shift Table top relocation test Trauma - typically avulsed from origin, failure of LCL to heal in anatomic position on lateral epicondyle in case of trauma Iatrogenic – surgical approaches, arthroscopic releases Chronic attenuation – longstanding cubitus varus (pedriatric SC fracture) which may create an external rotatory moment on the ulna, chronic overuse – chronic crutch walking (polio)

PRLI Radiographs Avulsion of LCL complex Degenerative changes Faber/King lesion (post capitellum lesion analogous to hill sachs) Drop sign --. Ulnohumeral distance > 4mm on plane lateral

Management Management Avoid further ligamentous injury Arthrotomy anterior to LUCL, anterior capsular release Suture anchor vs lateral ligamentous reconstruction Ligamentous graft – palmaris, plantaris Drill placed in supinator tubercle, second drill hole proximal to annular ligament creating bony tunnel (both extra-articular) Subsequent tunnels drilled in lateral epicondyle

Outcomes Jones et al, J Shoulder Elbow Surg, 2012 8 patients with purely ligamentous PRLI Surgical graft reconstructionr Mean f/u 7.1 years 75% resolution 25% occasional instability with ADLs Olsen and Sojberg, JBJS Brm 2003 Triceps tendon graft in 18 patients 4 persistent apprehension 5 moderate pain Sanchez-Sotelo et al, JBJS Br, 2005 12 patients, ligamentous repair, 32 reconstruction 5 persistent instability (3 from repaired, 2 from recon) 17 rated excellent 17 good 10 fair Similar Findings Lee and Teo, J Shoulder and Elbow, 2003 Primarily case reports on various techniques Decreased persistent instability with reconstruction Persistent pain associated with osteochondral lesion O’Driscoll et al, Instr Course Lect, 2001  90% satisfaction if no associated degenerative arthritis

References 1Hotchkiss, Rockwood and Green’s, 1996 2Matthew et al, JAAOS, 2009 3Mezera and Hotchkiss, Rockwood and Green’s, 2001 4Schneeberger et al, JBJS AM, 2004 5Beingessner et al, J Shoulder Elbow Surg, 2007 6O’Driscoll et al, JBJS, 1991 7Regan and Morrey, JBJS AM, 1989 8O`Driscoll et al, Instr Course Lect, 2003 9Dowdy et al, JBJS BR, 1995 10Morrey et al, CORR, 1991 11Pugh and McKee, 2002 12Pugh et al, JBJS AM, 2004 13Frothman et al, J Hand Surgery, 2007 14Chemama et al, Orthop Traumatol Surg Res, 2010 15Rodriguez-Martin et al, Int Orthop, 2011 16Jeong et al, J Orthop Sci, 2010 17Lindenhovius et al, J Hand Surgery 2008 18O’Driscoll, CORR, 2000 19Mehta and Bain, JAAOS, 2004 20Imatani et al, Jshoulder Elbow Surg, 1999

References 21Morrey and An, Clin Orthop, 1985 22Cohen and Hastings, JBJS Am, 1997 23Dunning et al, JBJS AM, 2001 24O`Driscoll et al, JBJS, 1991 25Jones et al, J Shoulder Elbow Surg, 2012 26Sanchez-Sotelo et al, JBJS Br, 2005 27Lee and Teo, J Shoulder and Elbow, 2003 28Olsen and Sojberg, JBJS Br, 2003 29Beuerlein et al, JBJS Am, 2004 30Hall and McKee, JBJS, 2005

Questions

Nathan L Sacevich circa 1998 Future ambition: sports medicine doctor Most memorable experience: losing the soccer championship Nickname: Nate Dogg Closet friends: Mack Daddy, Mr Sauce, P Squared (no mention of Travis) Remembered by: his “stylo” (his style?) When no one was looking: he liked to get his thug on People thought: he looked like a back street boy “the illest playa”