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Proximal humerus fractures anatomy and classification


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proximal humerus #s anatomy

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Proximal humerus fractures anatomy and classification

  3. 3. BONES  The bones that are involved in the formation of shoulder girdle include :  Humerus  Scapula with clavicle  Glenohumeral joint  Glenohumeral joint is a ball and socket type of synovial joint formed between the head of humerus and glenoid cavity of scapula.
  4. 4. SCAPULA • Flat bone on the postero lateral aspect of thorax between 2-7 ribs. • Spine of scapula divides the posterior surface into Supraspinous and infra - spinous fossa . • The scapula has three borders and three angles • The ant & post surfaces act as attachments for muscles acting on shoulder joint.
  5. 5. HUMERUS  The proximal end of humerus has a head, surgical and anatomical neck, greater and lesser tubercles.  The anatomical neck separates the head from the tubercles and is the attachment of shoulder capsule.  The surgical neck – Importance ?
  6. 6. FACTS ABOUT PROXIMAL HUMERUS  The humeral articular segment occupies approximately one third of a sphere, with a diameter of curvature averaging 46 mm.  The inclination of the humeral head relative to the shaft averages 130 degrees (with a range of 123 to 136 degrees).  The geometric center of the humeral head is offset an average of 2.6 mm posteriorly (range of -0.8 to 6.1 mm) and 7 mm (range of 3 to 11 mm) medially from the axis of the humeral shaft.  The humeral head is normally retroverted by an average of 20 degrees, with respect to the distal humeral interepicondylar axis.
  7. 7. MUSCLES  The muscles around the proximal humerus include :  Rotator cuff muscles : Supraspinatus, Infraspinatus, Teres minor and Subscapularis.  Deltoid  Pectoralis major  Teres major and Latissimus dorsi
  8. 8. Supraspinatus, infraspinatus and teres minor insert on the greater tubercle and cause lateral rotation . Subscapularis causes medial rotation along with pectoralis and T. major
  9. 9. GLENOHUMERAL JOINT AND THE LIGAMENTS  The shallow glenoid cavity is deepened by the glenoid labrum (fibrocartilagenous).  Only a third of the head articulates in the glenoid cavity at a given point.  Stabilized by the overlying muscles.  The ligaments include :  The joint capsule  Glenohumeral ligaments  Coracohumeral ligament  Coracoacromial arch  Transverse humeral ligament
  10. 10. NERVES & VESSELS  The nerves supplying the proximal humerus region include :  The axillary nerve  Suprascapular nerve  Lateral pectoral nerves  The vessels supplying the proximal humerus and the glenohumeral joint include :  Circumflex humeral arteries  Anterior circumflex  Posterior circumflex  Anastomosis around the shoulder joint.
  11. 11.  The main blood supply to the humeral head comes from the anterior circumflex humeral vessels through its anterolateral ascending artery.  The posterior circumflex vasculature becomes important after a fracture dislocation/ 3 or 4 part fracture.  The chances of osteonecrosis developing in a complex proximal humeral fracture is somewhat less as the soft tissue attachments of the fracture fragments maintain blood supply.  Only fractures with complete comminution with complete capsular disruption will go for osteonecrosis.  The axillary nerve lying at the surgical neck is prone for injury after a fracture.
  12. 12. BURSAE  Bursae are synovial fluid filled cavities present around the joint to reduce friction.  They directly communicate with the shoulder joint.  Subscapular bursa : protects the tendon of subscapularis  Subacromial bursa: between supraspinatus tendon and shoulder capsule inferiorly and acromion, coracoacromial arch and deltoid superiorly.
  13. 13. PATHOPHYSIOLOGY OF PROXIMAL HUMERUS FRACTURES  Proximal humerus fractures are mainly osteoporotic fractures  Can either be due to high energy trauma or low energy trauma.  The latter are mainly seen in elderly due to osteopenia & osteoporosis.  Occur either due to direct impact on the shoulder where the head gets fractured against the glenoid or indirect impact i.e fall on outstretched hand.
  14. 14.  Patients with direct injuries to shoulder tend to be more dilapidated as compared to the other group.  The maximum bone density is found in the subchondral bone right beneath the articular surface.  The posterosuperior quadrant of the humeral head is the most minerally dense area.
  15. 15. CLASSIFICATION OF PROXIMAL HUMERUS FRACTURES  Codman described that the proximal humerus tends to fracture along the lines of physeal fusion into four fragments: lesser tuberosity, greater tuberosity, head and the shaft.  Neers classification is the most commonly used classification presently.  Each of the four fragments are considered as unique parts only if they are separated by more than 1 cm or angulated by more than 45 degrees to one another
  16. 16.  Undisplaced or minimally displaced fractures are termed one-part fractures.  Displaced fractures are classified according to the number of displaced fragments, regardless of the number of secondary fracture lines, into two-, three-, or four-part configuration.  Fracture-dislocations are also classified according to the direction of displacement of the humeral head (anterior or posterior).
  17. 17. Normal anatomy
  18. 18. Undisplaced or Minimally Displaced One-Part Fractures (OTA Types A, B, or C)  Most common type of proximal humerus fracture (>50%)  Occurs in younger and fitter individuals with good bone stock.  Minimally displaced fracture lines can be present on the radiograph on any of the four parts.  Associated subluxation of shoulder joint may occur due to hemarthrosis, capsular atony.  Mostly treated by conservative management.
  19. 19. Undisplaced and stable one part fracture configurations
  20. 20. Two-Part Greater Tuberosity Fractures and Fracture-Dislocations (OTA Types A1.1, A1.2, and A1.3)  The spectrum includes : Isolated fractures & fractures with glenohumeral dislocation and nerve injury.  Terrible triad of shoulder ?  Mechanism:  Axial loading causing anatomical neck # with greater tuberosity #( 10 % prevalence).  Traction injury during a glenohumeral dislocation which causes greater tuberosity fracture due to avulsion injury.  Multifragmentary vs single fragment greater tuberosity fractures  Due to the risk of redislocation due to the muscle pull even 5mm displacement must be operated upon.
  21. 21. Seemingly isolated GT # may also have Anatomical neck # Properly oriented AP view needed
  22. 22. Rotator cuff deficient High riding humerus Retraction Causing pull Large frgmnt Small frgmnt
  23. 23. Two-Part Lesser Tuberosity Fractures and Fracture- Dislocations (OTA Type A1.3, Subgroup 4)  Very rare fractures, middle aged males, due to a very high force.  Forced external rotation causing isolated fractures or associated with posterior dislocation of shoulder.  The attached subscapularis tendon pulls the fragment medially.
  24. 24. Two-Part Extra-Articular (Surgical Neck) Fractures (OTA Types A2 and A3)  25 %, older individuals, low risk of osteonecrosis.  Three types of surgical neck fractures:  angulated, translated/separated, and comminuted  Angulated fractures:  Neutral alignment or head tilted in varus or valgus.  The shaft is usually impacted into the head hence good healing potential.  Translation/separation & comminution:  Can be mild or complete translation. Severe comminution – cortical discontinuity.  The head usually adopts a varus position due to pull of the rotator cuff and shaft dispalces anteromedially due to the pull of P. major
  26. 26. Two-Part Anatomic Neck Fractures (OTA Type C1.3)  Extremely uncommon injury  Associated with a high risk of osteonecrosis  When present occurs with posterior dislocation of shoulder joint
  27. 27. Three- and Four-Part Fractures Without Dislocation (OTA Types B1, B2, C1, and C2)  10 %, multifragementary, the variation in these fractures depend on the nature of deforming forces.  Anatomical neck fracture is a constant feature - movement of shaft in relation to head – 2* tuberosity fracture.  The various factors that play a part in the outcome of these #’s:  Humeral head angulation and displacement :  Neutral angulation :  Head in neutral/internal rotated if three part greater tuberosity #  Impacted valgus fracture :  The head faces superiorly (increased neck shaft angle) with splaying of tuberosities.  Impacted varus fracture :  The fractured humeral head is tilted into varus.
  28. 28. Valgus angulation fractures The 1 & 2nd pictures show undisplaced and mild valgus displacement The 3 & 4th pictures show severe valgus angulation with lateral translation of head with increased chances of osteonecrosis
  29. 29. Varus angulation with Inferior subluxation of humeral head
  30. 30.  Tuberosity fracture configuration & Displacement :  The tuberosities # secondary to head displacement.  The deformity tends to progress due to the muscle pull.  The three part G T # >>>>>>>>> L T #  The avulsed G T fragement moves posterosuperiomedially whereas the avulsed L T fragment anteromedially.  Humeral head viability and risk of osteonecrosis:  The risk of osteonecrosis increases with loss of capsular attachment to the head fragment.  Long posteromedial metaphyseal spike of bone attached to the humeral head--- better perfusion.  Preservation of a medial hinge in a valgus fracture  No reliable method is present to predict the occurrence of osteonecrosis.  Articular surface involvement :  Humeral head impacted into the glenoid causing head split.  The tuberosity fragments carry parts of humeral articular surface.
  31. 31. Pic 1: “Double shadow “of humeral Head pathognomic of head split fractures
  32. 32. Complex Fractures with Glenohumeral Dislocation (OTA Types B3 and C3)  Complete dislocation of fractured humeral head from glenoid cavity  Anterior fracture dislocations are more common than posterior fracture dislocations.  Most severe and have higher chances of developing ON.  Three part and four part anterior fracture dislocation are divided into :  Type I injuries  Type II injuries
  33. 33.  Type I injuries:  Viable Humeral Head With Retained Capsular Attachments  Young adults, high velocity injury.  The dislocated humeral head retains the capsule attachments through periosteal sleeve around lesser tuberosity.  Type II injuries :  more common, occurs in older females.  low-energy trauma, non viable humeral head.  the fracture resembles a three or four part valgus fracture, but with the humeral head dislocated anteroinferiorly, and not engaged on the glenoid.  The humeral head fractures in a valgus position and the exposed sharp medial calcar tears the capsule.  The capsule is torn which leads to increased risk of developing ON.
  36. 36.  Current classification systems for these fractures are based on anatomical and pathological principles, and not on systematic image reading.  These fractures can appear in many different forms, with many characteristics that must be identified.  However, many current classification systems lack good reliability, both inter-observer and intra-observer for different image types.  21 fracture characteristics are identified & they are applied along with classical Codman approaches to classify fractures.
  37. 37.  The new classification system, based on fracture characterization and using Codman classification graphs, presents a new image reading protocol with 21 fracture characteristics divided into five groups.
  38. 38. Bibliography  Rockwood and Greens fractures in adults 7th edition  Keith L Moore Clinically applied anatomy 6th edition  Frank H Netter atlas of Human anatomy, 4th edition.  77/
  39. 39. THANK YOU