![Outcome validation of the AO/OTA
classification system
Objectives:
• To determine whether a greater severity of injury as
documented by the AO/OTA code would correlate with
poor scores of:
- Impairment
- Functional performance
- Self-reported health status
• 200 patients, 3 Level I centers (Seattle, Nashville,
Baltimore): each patient with unilateral and isolated
lower extremity fracture [MF Swiontkowski et al 2000]](https://image.slidesharecdn.com/yigrsmwvrcimibbbeym9-signature-adb10c2637e590b7c6a491acd596fa5528ae126ffab840d71ae72dd1362a57b8-poli-160422234112/85/AO-Classification-29-320.jpg)
![Outcome validation of the AO/OTA
classification system
Conclusions:
C-type fractures had a significantly worse functional
performance and impairment compared with B-type
fractures, but B-type fractures were not statistically different
from A-type fractures [MF Swiontkowski et al 2000]
AO Classification
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
Impairment ROM Ambulation
A
B
C](https://image.slidesharecdn.com/yigrsmwvrcimibbbeym9-signature-adb10c2637e590b7c6a491acd596fa5528ae126ffab840d71ae72dd1362a57b8-poli-160422234112/85/AO-Classification-30-320.jpg)
![Outcome validation of the AO/OTA
classification system
Conclusions:
Further studies validating the AO/OTA fracture
classification system are required with adequate number of
cases for each region of injury to allow separate analysis of
the results [MF Swiontkowski et al 2000]
AO Classification
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
Impairment ROM Ambulation
A
B
C](https://image.slidesharecdn.com/yigrsmwvrcimibbbeym9-signature-adb10c2637e590b7c6a491acd596fa5528ae126ffab840d71ae72dd1362a57b8-poli-160422234112/85/AO-Classification-31-320.jpg)
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AO Classification
- 1. AOTrauma Principles Course Müller AO classification of fractures— long bones Joseph Borrelli, US
- 2. Learning outcomes • Explain the rationale and process of the comprehensive classification of fractures and how it can be used in clinical decision making • Not to provide a detailed guide to implementation • Discussion is limited to bones, segments, types, and groups, which is what is normally needed for every day clinical application and communication — . Bone Segment Type Group Subgroup
- 3. “The basis of all clinical activity, be it: • assessment and treatment, • investigation and evaluation, • learning and teaching, must be based upon sound data, properly assembled, clearly expressed, and readily accessible”. W M Murphy and D Leu
- 4. History • AO group saw need for “sound data” after ORIF became “acceptable” in order to assess the efficacy/risks • AO group started documentation of fracture treatment • Volume of data collected led to the development of a classification system • 1960s–70s almost every fracture had its own classification which led to the need for a universal system
- 5. “A classification is useful only if it considers the severity of the bone lesion and serves as a basis for treatment and for evaluation of the results.” Maurice E Müller, 1988
- 6. Comprehensive classification of fractures Müller AO Classification • Not only a way to document fractures • Helps to understand fractures in biomechanical and biological terms • Offers competence in: data acquisition, data storage, and data retrieval • Provides a framework a surgeon can recognize, identify, and describe the injury to the bone
- 7. Comprehensive classification of fractures Müller AO Classification The alpha-numeric notation serves: • Guide to assessment of fracture whatever depth the situation requires • Allows surgeon to record/store observations • Dependent upon accurate fracture description
- 8. Ground rules • Colors denote the progressive levels of severity • Describe fracture localization: - Bones and segments • Long bones divided into 1 diaphyseal, 2 epiphyseal and 2 metaphyseal segments • No distinction between epiphysis and metaphysis • Metaphysis is defined by a square length = widest part of epiphysis • “Center” of fracture needs to be determined
- 9. The principles of fracture classification 1 2 3 4 Each bone and bone region is numbered
- 10. The principles of fracture classification • Long bones are each divided into three segments • Labeled 1, 2, 3 from proximal to distal 1 2 3
- 11. The principles of fracture classification • Generally, proximal and distal segments are defined by a square whose sides = length of widest part of epiphysis • Exceptions: - Proximal femur - Proximal humerus - Malleolar segment
- 12. The principles of fracture classification • After documenting the location of the fracture (bone and segment), the “type” of fracture is determined (A, B, C): • Q. Is the fracture simple or multifragmentary? A. If simple = type A, if multifragmentary = type B or C • Q. If multifragmentary, is there a single wedge shaped fragment or a more complex fracture pattern? A. Wedge = type B, or more complex = type C
- 13. Which type of fracture? Types A, B, C: A = simple pattern B = multifragmentary, wedge C = multifragmentary, complex — . 12 22 32 42 A B C 12- 22- 32- 42-
- 14. The principles of the fracture classification Q. Which type of fracture? A. Metaphyseal/epiphyseal types (1 or 3) Q. Is the fracture extraarticular or intraarticular? A. If extraarticular = type A Q. If intraarticular, does it involve a portion of the articular surface or the entire articular surface? A. If partial-articular =type B, if complete-articular = type C
- 15. The principles of fracture classification Review of metaphyseal/epiphyseal types 21 13 33 41 23 43 A B C Which types of fracture? metaphyseal or epiphyseal Metaphyseal/epiphyseal types A B C Extra-articular fracture Partial articular fracture – part of joint remains in continuity with diaphysis Complete articular fracture – no part of joint remains in continuity with diaphysis
- 16. Fracture types for 11- and 31- Proximal humerus 11- A = extraarticular, unifocal B = extraarticular, bifocal C = intraarticular fracture 1 1- A C 3 1- B Proximal femur 31- A = trochanteric area B = neck fracture C = head fracture
- 17. Malleolar segment 44- • A = infrasyndesmotic lateral lesion • B = transsyndesmotic fibular fracture • C = suprasyndesmotic fibular fracture A B C
- 18. The principles of the fracture classification • Fractures are coded to the level of the type • Groups and subgroups are: - Ascending order of severity - According to the morphological complexities and difficulties inherent in their treatment and their prognosis — . Bone Segment Type Group Subgroup
- 19. Diaphyseal fractures To classify the fracture beyond the type continue with the “binary” concept of reasoning: • Q. Is the fracture simple or multifragmentary? A. If simple then type A fracture • Q. Was the fracture the result of twisting or bending? A. Twisting mechanisms typically results in a spiral type fracture = group 1, if bending, then = group 2 or 3 • Q. Bending? A. Then, is the inclination of the fracture greater or less than 30º ? group 2 if > 30º (A2) group 3 if < 30º (A3)
- 20. 12- 32-32- 42-42- C1 C2 C3A1 A2 A3 >30°>30° <30°<30° Diaphyseal groups — . B1 B2 B3
- 21. Diaphyseal fractures Type B fractures are multifragmentary wedge type fractures Groups for B type fractures: B1 = spiral wedge, B2 = bending wedge B3 = fragmented wedge 12- 32-32- 42-42- C1 C2 C3A1 A2 A3 >30°>30° <30°<30° Diaphyseal groups — . B1 B2 B3
- 22. Diaphyseal fractures Type C fractures are multifragmented complex fractures Groups for C type fractures: C1 = complex, spiral C2 = complex, segmental C3 = complex, irregular 12- 32-32- 42-42- C1 C2 C3A1 A2 A3 >30°>30° <30°<30° Diaphyseal groups — . B1 B2 B3
- 23. Metaphyseal/epiphyseal fractures These are segment 1 and 3 fractures Remember: A = extraarticular B = partial articular C = complete articular
- 24. Metaphyseal/epiphyseal fractures A1 = metaphyseal simple A2 =metaphyseal wedge A3 = metaphyseal complex A1 A2 A3
- 25. Metaphyseal/epiphyseal fractures B1 = lateral condyle, sagittal B2 = medial condyle, sagittal B3 = frontal plane fracture
- 26. Metaphyseal/epiphyseal fractures • C1 = articular and metaphyseal simple • C2 = articular simple,metaphyseal multifragmentary • C3 = articular and metaphyseal multifragmentary C1 C2 C3
- 27. Malleolar segment fractures 44- 44-A = infrasyndesmotic fibular fracture 44-B = transsyndesmotic fibular fracture 44-C = suprasyndesmotic fibular fracture A B C 44
- 28. Proximal humeral and femoral fractures Humerus proximal 11- 11-A extraarticular unifocal fracture 11-B extraarticular bifocal fracture 11-C articular fracture • Femur proximal 31- • 31-A trochanteric area fracture • 31-B neck fracture • 31-C head fracture 11 31 A B C
- 29. Outcome validation of the AO/OTA classification system Objectives: • To determine whether a greater severity of injury as documented by the AO/OTA code would correlate with poor scores of: - Impairment - Functional performance - Self-reported health status • 200 patients, 3 Level I centers (Seattle, Nashville, Baltimore): each patient with unilateral and isolated lower extremity fracture [MF Swiontkowski et al 2000]
- 30. Outcome validation of the AO/OTA classification system Conclusions: C-type fractures had a significantly worse functional performance and impairment compared with B-type fractures, but B-type fractures were not statistically different from A-type fractures [MF Swiontkowski et al 2000] AO Classification 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 Impairment ROM Ambulation A B C
- 31. Outcome validation of the AO/OTA classification system Conclusions: Further studies validating the AO/OTA fracture classification system are required with adequate number of cases for each region of injury to allow separate analysis of the results [MF Swiontkowski et al 2000] AO Classification 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 Impairment ROM Ambulation A B C
- 32. Classification • Bone = 3 • Segment = 3 • Type = C • Group = 3 • 33-C3 • Bone = • Segment = • Type = • Group =
- 33. Classification • Bone = 3 • Segment = 2 • Type = A • Group = 3 (bending, < 30°) • 32-A3 • Bone = • Segment = • Type = • Group =
- 34. Summary • AO comprehensive classification of fractures is: - Comprehensive - Adaptable - Consistent - Dynamic • Depends on the surgeon’s ability to accurately assess the fracture pattern