1 / 38

Medial Elbow Instability

Medial Elbow Instability. Geoff Wilkin Academic Half-Day University of Ottawa, Div. of Orthopaedic Surgery April 19, 2012. Outline. Biomechanics of Throwing Medial Elbow Instability Valgus Extension Overload. Throwing Biomechanics. Throwing Biomechanics. Windup.

yamin
Télécharger la présentation

Medial Elbow Instability

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Medial Elbow Instability • Geoff Wilkin • Academic Half-Day • University of Ottawa, Div. of Orthopaedic Surgery • April 19, 2012

  2. Outline • Biomechanics of Throwing • Medial Elbow Instability • Valgus Extension Overload

  3. Throwing Biomechanics

  4. Throwing Biomechanics

  5. Windup • Weight to trailing leg, lead leg flexes • Trunk rotates away from target • Elbow flexed • Forearm pronated • Ends when ball leaves glove hand

  6. Early Cocking • Stride initiation • Lead leg and hip drive toward target • Shoulder abduction and ER • Elbow extension controlled eccentrically • Ends when lead foot contacts ground

  7. Late cocking • Shoulder abduction to 90° and ER to maximum (150-180°) • Elbow flexes to ~90° • Forearm pronates • Leading leg decelerates and pelvis rotates toward target • L-spine lordosis increases shoulder ER • Ends at max shoulder ER

  8. Acceleration • Humerus rapidly transitions to IR, propelled by body rotation • Trunk flexes, elbow extends • Acceleration ~600,000 deg/sec2 • Max varus torque ~64 N⋅m • Ends with ball release

  9. Deceleration/Follow-through • Nearly equally rapid deceleration (~500,00 deg/sec2) • Arm continues into horizontal adduction, shoulder IR, elbow extension • Posterior shoulder girdle muscles, cuff/deltoid, & elbow flexors decelerate arm • Weight transfer to lead leg

  10. Anatomy • Medial Collateral Ligament • Anterior Bundle • Strongest (260 N) • Primary Valgus stabilizer • Posterior Bundle • Transverse Bundle

  11. Anterior Bundle • Origin: anteroinferior medial epicondyle • slightly posterior to axis of rotation = cam effect • Anterior Band: 0-60/90 • Posterior Band: 60/90-120 • Insertion: • sublime tubercle • ~18mm distal to coronoid tip

  12. Valgus Restraint of MCL • Morrey & An, AJSM 1983 • 31% at 0° • 54% at 90° (less bony stability) • Morrey et al., CORR 1991 • Sequential removal: radial head, PMCL, AMCL • MCL is primary valgus stabilizer • Radial head important secondary stabilizer when MCL deficient

  13. Muscles • Flexor-pronator mass • Dynamic secondary stabilizers to valgus stress • Protect UCL • FCU may be most important due to synergistic position Davidson et al., AJSM 1995

  14. Muscle • Small moment arm • Mechanical disadvantage • Limited ability to compensate for MCL deficiency • Hamilton et al., JSES 1996 • No compensatory increase in flexor/pronator activity in pitchers with MCL deficiency

  15. Medial Elbow Instability

  16. Pathogenesis • Valgus overload in flexion • Acute rupture • valgus force exceeds yield strength of UCL • Repetitive microtrauma

  17. Role of Throwing Mechanics • Aguinaldo & Chambers, AJSM 2007 • Increased elbow valgus loads with: • Early trunk rotation • Increased shoulder ER • Decreased elbow flexion • Sidearm delivery

  18. Clinical Presentation • Medial-sided elbow pain • Insidious onset, occasionally acute • Late cocking & early acceleration phases • Weakness, loss of control & stamina towards end of game • +/- ulnar nerve symptoms

  19. Physical Exam • ROM (may pitchers lack terminal extension) • Ulnar nerve • motor, sensory, subluxation, Tinel’s • Flexor-pronator strength

  20. Physical Exam • Static Valgus Stress • pain at 70-90° • “Milking test”

  21. Physical Exam • “Moving Valgus Stress test” • pain in mid-flexion (70-120°) • most accurate predictor of UCL injury • Sens: 100% • Spec: 75% O'Driscoll SWM et AL., Am J Sports Med. 2005 Feb.;33(2):231–239.

  22. Imaging • Xray (AP, Lat, Obl) • Oblique axial at 110° • posteromedial osteophytes • valgus stress views • 0.5-2mm widening • utility is questionable (differences in technqiue, normal widening) • calcification of UCL

  23. Imaging • MRI • Acute Injury • Sens: 57-79% • Spec: 100%

  24. Management • Non-operative • Usually successful in non-throwing athletes • Rest, activity restriction • Graduated return to activities

  25. Management • Acute Rupture • Richard et al, JBJS(A) 2008 • 11 athletes with acute UCL rupture • Direct repair through drill holes or with suture anchors • 11/11 had avulsion of UCL origin and superficial flexor-pronator muscles • 3/11 acute ulnar nerve palsies recovered by 6 months • 10/11 regained full ROM & returned to previous level of sport within 4-6 months

  26. Management • Chronic Valgus Instability • UCL reconstruction • Palmaris longus, gracilis, EHL, allograft • Initially described by Jobe (1986) • Figure-8 through bone tunnels • Routine detachment of flexor-pronator tendon & ulnar n. transposition

  27. Management • Variations • Docking technique • Interference screw

  28. Outcomes • Jobe et al., JBJS(A) 1986 • 10/16 professional pitchers returned to same level of sport • 2/16 ulnar n. palsy, 3/16 ulnar n. paresthesias • Thompson et al., JSES 2001 • Flexor-pronator split, no ulnar n. transposition • 5% (4/83) ulnar n. symptoms • 82% “excellent” (return to same level >12 mo.), 12% “good” (return 1 level lower)

  29. Rehab • 1 week - posterior splint • 1-3 weeks - hinged brace 10-110 • 3-4 weeks - full motion in brace • 4-6 weeks - sport specific activites • 12 weeks - gentle throwing with brace • 16 weeks - progress throwing out of brace

  30. Valgus Extension Overload

  31. Etiology • Chronic UCL laxity • Impingement of the posteromedial tip of the olecranon on medial wall of olecranon fossa

  32. History/Physical • Posterior or posteromedial elbow pain • Pain at ball release • late acceleration/deceleration vs. late cocking/early acceleration for UCL • Valgus stress in 20 and forced terminal extension • Tender posteromedial olecranon tip

  33. Imaging • Posteromedial osteophytes • can be asymptomatic, & absence doesn’t exclude VEO • found in ~65% of professional baseball players undergoing sugery

  34. DDx • Ulnar n. instability • anterior subluxation with flexion >90° • Olecranon stress fractures • symptoms during & after throwing. • pain more distal and lateral • Medial epicondylitis • tender epicondyle

  35. Management • Initial Presentation • Active rest from throwing x 10-14 days • Recurrent Episodes • 4-6 weeks rest, more gradual return to throwing

  36. Management • Operative • Arthroscopic debridement of posteromedial olecranon tip • How much? • Levin et al., JSES 2004 • 8mm

  37. Prevention • Prevent overuse/overload of MCL • Good throwing mechanics • Pitch maximums • Minimize breaking pitches (sliders, curveballs, etc)

  38. Thank you

More Related