1. Sprains and Strains The Biomechanics of Injury Janus D. Butcher UMD School of Medicine June 2007

2. Sprains and Strains Biomechanical Model History and Physical Initial Treatment Rehabilitative Treatment Illustrative Cases/Complications

3. Definitions A sprain is?

4. Definitions A sprain is? Ligament Injury

5. Definitions A strain is?

6. Definitions A strain is? Musculotendinous Injury

7. Biomechanical Model of Acute Ligament/tendon Injury Acute injury occurs when a ligament or tendon is subjected to tensile stress (load) that exceeds it’s tensile strength.

8. Biomechanical Model of Overuse Injury to Ligament or Tendon Overuse injury occurs when ligament or tendon is subjected to repetitive tensile stress at a frequency, duration, and intensity that exceed its capacity for recovery or repair.

9. Concentric Contraction/Load Muscle shortens as it exerts force.

10. Eccentric Contraction/Load Muscles are forced to lengthen while exerting a force

11. Biomechanical Model Factors That Increase Risk of Injury Increased tensile stress Decreased tensile strength Decrease capacity for repair

12. Increased Tensile Stress Eccentric overload Ballistic velocity Weak supporting dynamic stabilizers Proprioceptive deficit

13. Proprioception is….. Balance

14. Decreased Tensile Strength Prior injury Disuse atrophy Degenerative disease Aging Connective tissue disease Medications

15. Decreased Capacity for Repair Recurrent injury Aging Connective tissue disease Vascular disease Diabetes Smoking Medications Other

16. Biomechanical Model Injury Prevention Decrease tensile load (stress) Increase tensile strength Enhance ability for repair

17. Decrease Tensile Load Extrinsic Factors Proper equipment Proper technique Bracing/taping Orthotics

18. Increase Tensile Strength Intrinsic Factors Resistance exercise (eccentric loading) Balanced strengthening of dynamic stabilizers General conditioning Proprioception training

19. Enhance Capacity for Repair Conditioning Lifestyle Drugs

20. Sprains and Strains Mechanism of Injury Deformation injury produced by stress Musculotendinous injuries usually eccentric overload Ligament injuries usually non-anatomic stress

21. Musculotendinous Injury Eccentric overload

23. Ligamentous Injury Non-Anatomic Stress

24. Grading Severity Grade 1: Micro-tears (stretch) Grade 2: Macrotears (partial tear) Grade 3: Complete disruption

25. Joint Laxity vs. Joint Instability

26. Joint Stability Musculotendinous unit and ligaments are symbiotic in joint stability Static stabilizer vs. dynamic stabilizers

27. Functional Instability Not the same as joint laxity Frequently describes “giving out” Unable to do certain activities Jump Pivot Decelerate Cut

28. Functional Instability Possible Causes Ligamentous laxity Motion deficit Strength or endurance deficit Proprioception issues Internal derangement (fracture/loose body)

29. Sprains and Strains Physical Exam Inspection Swelling Bruising Pain Provocation Motion Palpation

30. Physical Exam Palpation Crepitance Weakness Palpable defect

31. Physical Exam Stress Testing Laxity End Point

32. Modifiers of Endpoint Muscle tone Muscle guarding Joint effusion Soft tissue swelling Mechanical block Ligamentous endpoint

33. Physical Exam Caveats 1.The patient will tell you what’s wrong 2.The exam may or may not be confirmatory

34. Initial Treatment PProtection Ractive Rest Iintermittent Ice CCompression EElevation Manti-inflammatory Medication Manti-inflammatory Modalities

35. Rest

36. A four letter word

37. Rest A four letter word Relative rest implies ACTIVE rest

38. Active Rest Treatment Implications Stimulates healing of tissue Allows maintenance of general conditioning Prevents loss of strength in supporting structures Maintains joint ROM Addresses proprioception retraining

39. Active Rest Activity is performed in a biomechanically normal position Protected from abnormal motion No pain with activity No pain or swelling after activity

40. Rehabilitative Exercise Goals Control immediate inflammatory response Promote normal tissue healing Increase tensile strength Address collateral joint effectors Maximize functional stability

41. Who Gets Therapy? Everyone!

42. Return to Sport Absence of pain is not appropriate end- point of treatment-Webb Strength >80% on normal ROM normal Proprioception normal

43. Return to Sport Bracing Almost everyone Functions Support Joint Enhance proprioception Ensure Appropriate fit Use with specified activities

44. Case 24 year old student hockey athlete slid feet first into the boards. He saw it coming and tried to stop his crash. Felt a ripping sensation in his left thigh and was unable to bear weight.

45. Physical Exam

46. Swelling Bruising Palpable defect in the vastus lateralis Negative extensor lag

47. Imaging Xray- none initially MRI

48. Treatment PKnee immobilizer RKnee immobilizer/flexion block splint IIce CAce Wrap EElevation MNo MNSAIDS (Indocin)

49. Therapy 1.Initial rest until able to weight bear 2.Gentle stretching 3.Gradual eccentric exercise (2-4 weeks) 4.Dynamic flexibility and strengthening 5.Return to sport 4 to 8 weeks

50. Complications Re-injury Complete tear MO

51. Prevention of Myositis Ossificans Avoid repeat injury Avoid aggressive activity early Indocin 50mg t.i.d.

52. Case 33 year old runner sprained ankle 1 year ago. Was very bruised and swollen but symptoms subsided without treatment Now has had multiple ankle sprains over the past year and ankle feels very unstable.

53. Physical exam Inspection: Normal Tender in the anterio- lateral corner Weakness in peroneus brevis ROM: diminished dorsiflexion

54. Physical exam Anterior drawer/talar tilt are normal Proprioception: Poor balance on injured side

55. Diagnosis? 1.Ankle sprain (recurrent grade 2 or less) 2.Synovitis 3.Functional instability

56. Treatment Brace Strengthing ROM Proprioception

57. Questions?