Soft Tissue Injury

1. Soft Tissue Injury Lutul D. Farrow, MD Assistant Professor, Clinical Orthopaedic Surgery University of Arizona College of Medicine Department of Orthopaedic Surgery

2. Disclosure Statement I have not received anything of value from or own stock in any commercial company or institution as it relates to this research study

3. Outline Introduction Musculotendinous injury Ligament injury Treatment Prevention Conclusion

4. Case Presentation • 22 year old college hurdler • Chief Complaint: “Sharp pain in the back of my thigh” • HPI • Going over the last hurdle and felt a “twinge” in the back of my thigh. I had to “pull-up” from the race. Couldn’t sprint to the finish, but was able to hobble across the finish line.

5. Case Presentation • Examination (4 days after injury) • Limps into YOUR office on crutches • Swelling in posterior thigh • Severe ecchymosis (bruising) • Pain in posterior thigh, right in center.

6. Musculotendinous Injury Crisco JJ, Jokl P, Heinen GT, et al. A muscle contusion injury model. Am J Sports Med 1994; 22: 702-10 Garrett Jr WE. Muscle strain injuries: clinical and basic aspects. Med Sci Sports Exerc 1990 Aug; 22 (4):436-43 • Muscle injuries very common in active individuals • Up to 90% of sports injuries • Can be painful/inconvenient injuries • Huge socioeconomic impact • Loss productivity • Loss income

7. Musculotendinous Injury • Types of muscle injury • Laceration • Cramps • Delayed-onset soreness • Contusion • Muscle strains

8. Musculotendinous Injury Menetrey J, Kasemkijwattna C, Fu FF, Moreland MS, Huard J. Suturing versus immobilization of a muscle laceration. Am J Sports Med. 1999;27:222-229 • Lacerations • Sharp cutting/transection • Typically trauma-related • Heal via scar • Distal denervation • Significant loss of ability to produce tension

9. Musculotendinous Injury • Muscle Cramps • Common “injury” • Most commonly – gastrocs • Can occur ANYTIME • Cause unknown • Ca2+ • Mg2+ • Na2+ • Initiated in motor nerve • Treatment

10. Musculotendinous Injury • Delayed-Onset Muscle Soreness • Pain following unaccustomed vigorous activity • Delayed timing • Small ruptures in muscle • Connective tissue

11. Musculotendinous Injury • Muscle Contusion • Typically direct blow • Damage/partial disruption of muscle fibers • Intramuscular hematoma • Quadriceps • Gastrocnemius • Treatment

12. Musculotendinous Injury • Muscle Strain • Stretching injury • Combination of stretch and activation • 50% of athletic injuries • Affects athletes and non-athletes alike

13. Musculotendinous Injury • Etiology of Muscle Strains • Certain muscles injured more than others • “2-joint” muscles most susceptible • Can act to limit joint motion • Prone to stretch at multiple joints

15. Musculotendinous Injury • Common examples • Biceps brachaii • Rectus femoris • “Hamstrings” • Gastrocnemius • These are some of the more commonly strained muscles

16. Musculotendinous Injury • Etiology of Muscle Strains • Mode of muscle activation can predispose to injury • Eccentric contraction vs Concentric contraction

17. Musculotendinous Injury • Concentric Contraction • Muscle shortens as it contracts • The way most think of contraction

18. Musculotendinous Injury • Eccentric Contraction • Muscle lengthens as it contracts • Typically to “slow-down” extremity • High potential for injury • Lots of internal energy created

19. Musculotendinous Injury Classification

20. Musculotendinous Injury

21. Musculotendinous Injury This is your friend, what do you do?

22. Musculotendinous Injury • Muscle Healing • Predictable set of events • Inflammation (Destruction) • Muscle fiber Regeneration (Repair) • Collagen synthesis (Remodeling)

23. Musculotendinous Injury • Inflammatory phase • Dolor • Rubor • Calor • Tumor

24. Musculotendinous Injury • Inflammatory phase • Platelets • WBC’s • Injured myocytes release: • Cytokines • Growth factors

25. Musculotendinous Injury • Inflammatory phase • Following muscle injury: • Disruption of vasculature • “Damage control” • Platelets • Proinflammatory mediators • Vasodilation and increased permeability

26. Musculotendinous Injury IL-1 IL-8 TNF-α • Inflammatory phase • Neutrophils • Within 1st hour • Peak at 24 – 48 hours • Clear necrotic debris • Release cytokines • “Collateral damage”

27. Musculotendinous Injury

28. Musculotendinous Injury • Inflammatory Phase • Macrophages • Phagocytosize Cellular debris • Peak response at 7 days • Growth factors/cytokines • IGF-1 • PDGF • IL-6

29. Musculotendinous Injury • Muscle regeneration phase • Satellite Cells • Quiescent cells • Activated by growth factors • bFGF • TGF-β • IGF-1

30. Satellite Cells +

31. Musculotendinous Injury

32. Musculotendinous Injury Collagen synthesis phase “Dueling banjos” Collagen types I and III Key for tensile strength and architecture

33. Musculotendinous Injury • Treatment • RICE • Rest • Ice • Compression • Elevation • NSAID’s

34. Musculotendinous Injury • Tendon Injury • Mechanisms of injury • Similar to that of muscle • Less susceptible to contusion • Typically tensile

35. Musculotendinous Injury • Types of Tendon Injury • Avulsions • Best case scenario? • Intrasubstance tears • Partial versus complete? • Laceration • Not uncommon

36. Musculotendinous Healing • Tendon Healing • Three phases: • Inflammatory phase • Reparative phase • Remodeling phase

37. Musculotendinous Injury • Tendon Healing • Inflammatory phase • Injury until 8 – 10 days • Blood clot forms • Inflammatory cells • Fibroblasts and capillary buds

38. Musculotendinous Injury • Tendon Healing • Reparative phase • Begins week 1 • Maximum at 4 weeks • Perpendicular collagen • Re-aligns parallel

39. Musculotendinous Injury • Tendon Healing • Remodeling phase • Begins at 15th day • Lasts for up to 1 year

40. Musculotendinous Injury • Tendon Healing • Treatment • Excellent healing potential • When apposed • Bony avulsions • Immobilization is key! • Complete tears • Surgery

41. Musculotendinous Injury • Prevention • Cyclical stretching • Warm-up • Viscoelastic material • Also stretches myotendinous unit • Jury’s out

42. Case Presentation 32 y.o. Soccer player CC: “My knee feels funny” HPI: “I was trying to stop when my left leg slipped and my right leg bent behind me. I felt a ‘pop’ and I couldn’t go back to playing.”

43. Case Presentation • Examination (immediately post-injury) • Swelling • No deformity • Pain on palpation of medial knee

44. Ligament Injury

45. Ligament Injury • Epidemiology • Up to 45% of MSK injuries • Affect 5 – 10% of people • 30 – 40 million treated/year

46. Ligament Injury • Ligament • Band of tough, dense connective tissue • Connect bones to bones • Limit joint motion • Critical for joint stability • Stabilize joint through range of motion

47. Ligament Injury • Mechanism of injury • Typically fail in tension • When joint moves into non-physiologic positions • Translation and rotation • Variable extent of injury

48. Ligament Injury

49. Ligament Injury • Ligament Healing • Similar staging • Inflammation • Repair • Remodeling • Non-sequential

50. Ligament Injury • Ligament Healing • Inflammatory Phase • First 48 – 72 hours • Damaged cells • Release inflammatory mediators • Vasodilation • Increased permeability