ankle instability: what we know and where we are going

1. Ankle Instability: What we know and where we are going Thomas W. Kaminski, PhD, ATC, FACSM Director of Athletic Training Education Associate Professor Human Performance Laboratory University of Delaware

2. What does a horse have to do with ankle instability?

3. Background

4. Why study ankle instability? 23,000 ankle sprains per day in US One sprain per 10,000 people daily >90% of ankle sprains are to lateral ligaments

5. Cumberland Ankle Instability Tool (CAIT) Designed to measure functional ankle instability 9 questions related to subjects� perception of ankle stability during various activities Shown to be valid and reliable How do you score?

6. Ankle Instability: Soon to be the buzz word of the 2000�s? ACL injuries dominated the sports medicine literature during the last decade of the 20th century, will ankle instability takes it�s place in this current decade? Over the past 4 decades --- hundreds of articles dealing with lateral ankle sprains and ankle instability, yet epidemiological evidence shows no reduction in injury rates What are we doing wrong?

7. Epidemiology 55-72% report residual symptoms 6 months post-injury (Braun, 1999) Recurrence rates >70% in basketball (Yeung et al, 1994) 30-40% report longstanding instability

8. Epidemiology Most common predisposition to an ankle sprain is the history of a previous sprain 55% of ankle sprains are not treated by a health care professional (McKay et al, 2001)

9. A Public Health Issue? Cost of initial treatment and follow-up rehabilitation Strong link with an increased risk for osteoarthritis and articular degeneration

10. Three Major Contributors: to Ankle Stability Congruity of the articular surfaces of the joints when loaded

11. Three Major Contributors: to Ankle Stability Static ligamentous restraints

12. Three Major Contributors: to Ankle Stability Musculotendinous units that allow for dynamic stabilization of the joints

13. The Lateral Ankle Sprain Often involves sprains of the ATFL (�collateral ligament of the ankle�) & CFL Instability of the talocrural and subtalar joints Dynamic stabilization = peroneal muscles

14. Mechanism of Lateral Ankle Sprain Excessive supination of the rearfoot about an externally rotated lower leg Often after contact of the rearfoot during gait or while landing from a jump Increased plantar flexion at initial contact increases likelihood of suffering a LAS ATFL ruptures ? transverse plane motion (IROT) of the rearfoot increases ? stress on the remaining ligaments Likely to result in damage to the talocrural joint capsule and ligamentous stabilizers of the subtalar joint

15. Who Is At Risk? Structural Predispositions: Increased tibial varum Non-pathological talar tilt Functional Predispositions: Poor postural control Impaired proprioception High E:I or PF:DF strength ratios

16. Multifactorial Nature of Ankle Instability Hertel J. Functional instability after lateral ankle sprain. Sports Medicine. 2000; 29: 361-371. Hertel J. Functional anatomy, pathomechanics, & pathophysiology of lateral ankle instability. J Athletic Training; 2002; 37: 364-376. Hertel J. and Kaminski T.W. Position statement from the 2nd International Ankle Symposium. Journal of Orthopaedic and Sports Physical Therapy; Summer 2005.

17. Ankle Instability Mechanical instability is described as motion exceeding the physiologic limit Functional instability disability to which patients refer when they say the foot tends to �give way� (Freeman et al. - 1965) joint motion beyond voluntary control, but not necessarily exceeding physiologic ROM (Tropp - 1985)

19. Mechanical Instability Pathological Laxity: ? talar tilt upon inversion stress Physical exam Stress radiography Consider rotational instabilities

20. Mechanical Instability Impaired Arthrokinematics: Anteriorly/inferiorly displaced fibula (lateral malleolus) ATF slack Supination = talus > ROM before ATFL becomes taut Does this positional fault lead to repetitive sprains? Restricted posterior glide of the talus on the tibia during dorsiflexion Talus is placed in a more PF position Does this restriction lead to repetitive sprains?

21. Mechanical Instability Synovial and Degenerative Changes: Anterolateral Impingement Syndrome Synovial inflammation in the talocrural joint capsule Sinus Tarsi Syndrome Synovial inflammation in the posterior subtalar joint capsule Increase in reports of osteoarthritis

23. Pathophysiology of Ligament Injury on Proprioception and Neuromuscular Control

25. Functional Ankle Instability Assessment Tools: muscular strength isometric isokinetic stabilometry peroneal reaction times Star Excursion Balance Test (SEBT) time to stabilization landing patterns and ground reaction forces time to peak torque (power)

26. Functional Instability Impaired Proprioception: Altered muscle spindle activity in the peroneals Altered articular mechanoreceptor activity Can we improve proprioception through rehabilitation?

27. Functional Instability Altered Neuromuscular Control: Impaired neuromuscular recruitment patterns Reflexive responses to inversion/supination perturbations Peroneal response is impaired: Impaired proprioception? Slowed nerve conduction velocity? Central impairments in NM recruitment strategies?

28. Functional Instability Impaired Postural Control: Impairments during single-leg stance Acute ankle sprains Ankle instability Peripheral or central changes in proprioception and neuromuscular control?

30. Functional Instability Strength Deficits: Decreases in inversion and eversion strength? Functional strength ratios: (involving both CONCENTRIC and ECCENTRIC muscle actions) E:I PF:DF Time to peak torque (power) Are the deficits due to: Muscle damage or atrophy? Impaired NM recruitment ? functional insufficiency in the dynamic defense mechanism?

31. Previous AI Strength Reports Kaminski et al. (JAT - 1999) no differences in eversion strength between the two groups Franklin et al. (JAT - 1999) CON E:I ratios were consistently higher in FAI group, yet not significantly different Kaminski et al. (MSSE - 2001) Examination of reciprocal muscle group E:I ratios in those with FAI No differences in strength between ankles in those with unilateral FAI Kaminski et al. (MSSE � 2003) There were no significant differences (P>.05) in AT strength ratios between the groups (FAI vs. control), ankles (affected vs. unaffected), or tests (pre vs. post fatigue).

32. CON E : ECC I Functional Strength Ratios

33. ECC E : CON I Functional Strength Ratios

34. Time to PT Measures Significant differences in PT, time to PT, and angle of PT were noted between the two groups for both ECC EV at 30�/sec and ECC INV at 120�/sec (ACSM 2005)

35. Time to PT and Fatigue Post-fatigue TPT (0.248 sec) was significantly different (P = 0.025) than the pre-fatigue TPT (0.302 sec) for eccentric INV torque produced at 120�/sec. (NATA 2005)

36. Teasing out the �Function� in Functional Ankle Instability

37. Teasing out the �Function� in Functional Ankle Instability Function � from Latin �functio� meaning to perform, the special action or physiologic property of an organ or other part of the body (Stedman�s) What constitutes ankle �function�? Speed Agility Hopping Jumping Landing Balance Proprioception Stability Strength Muscle Reaction Time Joint Laxity Kicking Subjective considerations

38. Recent Studies Utilizing Functional Performance Tests in those with FAI Hals, Sitler & Mattacola 2000 � JOSPT Utilized postural sway measures to classify subjects as FAI Munn et al. 2002 � JSR Triple-crossover hop for distance and 6-m shuttle run tests unable to detect differences between injured and uninjured ankles Demeritt et al. 2002 � JAT No differences between groups for cocontraction, shuttle run, or agility hop Docherty et al. 2004 � JAT Fig-8 hop, up-down hop, side hop, single hop Fig-8 hop & side hop deficits in those with CAI

40. Could this ankle injury been prevented?

41. Where Do We Go From Here? How prevalent is ankle instability? A problem that is not limited to athletes! How are instabilities of the ankle classified? Can ankle instability be prevented? Is there something we are doing in the initial treatment that we need to do differently?

42. How Big is the Problem? Lack of good prospective studies Incidence (rate) vs. Prevalence (extent)? Outcome studies (multicenter) are needed to examine the prevalence of FAI Many anecdotal accounts Residual lifestyle-limiting sx�s (pain, swelling, instability) Residual sx�s of crepitus, weakness, instability, and stiffness in athletes with multiple episodes of ankle sprains Any connection with syndesmotic sprains? Any connection with initial treatment?

43. Lentell Classification Scheme Lentell et al. (1990) Past history of inversion injury that required protected weightbearing and/or immobilization No history of fractures to either extremity The involved ankle was reported to be Chronically weaker More painful Less functional Current subjective complaints were reported secondary to past history of sprain No significant trauma 3 months prior to testing Subject is full weightbearing, without limp, for at least 3 weeks prior to testing Subject is not currently undergoing any formal rehabilitation Functional use of the ankle has plateaued or peaked since original insult

44. Ankle Joint Functional Assessment Tool (AJFAT)

45. Ankle Performance Test Protocol

46. Scoring of Symptoms after Ankle Fracture

47. Self- Report Questionnaire for Ankle Function

48. Functional Ankle Instability Questionnaire 1. Concerning your purported ankle instability is this injury involving only one ankle? Y N If yes, did the initial episode involve your ankle �rolling inward�? Y N (If no, do not continue to fill out this questionnaire!) 2. What ankle suffers the instability? R L 3. Did the initial injury to your ankle require crutches and/or immobilization of any form (cast, braces, etc�)? Y N 4. Have you had any fractures (breaks) in either of your ankles? Y N 5. Is the injured/unstable ankle chronically weaker, more painful, �looser�, and less functional than your uninvolved ankle? Y N

49. Functional Ankle Instability Questionnaire 6. Do you ever have episodes of your ankle �giving way� or �rolling over� during daily activity (athletic or otherwise)? Y N 7. Do you attribute your current instability to past injuries to the affected ankle? Y N 8. Have you had an episode of injury (�your ankle was hurt�, �you were in great pain�) to the affected ankle within the last 3 months? Y N 9. Have you been walking around unassisted without a �limp�, for at least the past three months? Y N 10. Are you currently involved in a �formal� rehabilitation program for the affected ankle? Y N - If you answered yes, please describe here. 11. Can you describe a symptom(s) of your ankle �giving way�?

50. Clinical Examination of Ankle Stability Swelling Present? Y N Ecchymosis Present? Y N Anterior Drawer Test Right ankle + - Left ankle + - Talar Tilt Test Right ankle + - Left ankle + - To qualify as FAI, questions 3,5,6,7, and 9 should be answered �yes�. Questions 4, 8, and 10 should be answered �no�, in addition no clinical signs of mechanical instability can be present. Cleared for participation in the study? Y N

51. Short Form (SF) � 36 Health Survey Generic health status questionnaire 5-10 minutes to complete 10 items related to �physical functioning� Recommended by the AAOS

52. Fibular-Translation Test

53. Medial Subtalar-Glide Test

54. Issues Surrounding Current Classification Criteria Subjective nature of the criteria How many sprains does it take to be classified as unstable? Lack of �functional� assessment Most studies have not R/O the presence of �mechanical� instability

55. A Classification Proposal from the International Ankle Consortium All patients must have a history of a previous significant ankle sprain and symptoms of instability (frequent �giving way� and/or weakness) for at least 3 months. AI must be significantly impacting the patient�s ankle function as reflected by one or more of the following: Days of training or competing lost due to injury or fear of injury. Having to seek professional help for this problem. Needing bracing or taping to exercise or compete in sports. Requiring medication or rehabilitation interventions (modalities) as a result of �giving way� episodes.

56. International Ankle ConsortiumClassification Categories (proposed) IAC Functional category I Patient has no problems with activities of daily life (ADL). Patient is aware of weakness/instability, but ankle dysfunction is not severe enough that it prevents an active lifestyle. Brace or support not needed to compete, but may be worn occasionally. � IAC Functional category II Patient does not have significant problems with ADL. Patient�s unstable ankle is very likely to �roll� or �give way� if competing or exercising without support. Active lifestyle can be maintained with bracing. Patient occasionally avoids or discontinues sport or activity, for fear of sprain or pain.

57. International Ankle ConsortiumClassification Categories (proposed) IAC Functional category III Patient�s unstable ankle gives way regularly with ADL. Patient uses brace occasionally for activities of daily life. Patient has given up certain activities out of concern for re-injuring the unstable ankle.

58. Can We Prevent Ankle Instability? Should prevention programs be initiated much like those recently started for ACL injuries?

59. Can We Prevent Ankle Instability? What factors should we consider? ROM strength muscle endurance CV endurance appropriate proprioception agility & coordination Taping/bracing Immobilization time

60. As the world �ankle� turns �. Ankle injuries are here to stay. What can be done to prevent re-injury? How do we bridge the gap between research and reality?

61. Today�s lecture can be viewed at the following URL address:

62. Thank You