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Biomekanik cubiti mjd

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The document summarizes the biomechanics of the elbow joint. It discusses the static and dynamic stabilizers of the elbow, including the primary static constraints of the ulnohumeral articulation, anterior bundle of the MCL, and lateral collateral ligament complex. It also describes the osteology and articular surfaces of the elbow joint and how flexion and extension enhance osseous stability. Key soft tissues like the medial and lateral collateral ligament complexes are explained. The roles of the coronoid process, radial head, and muscles in dynamic stabilization are highlighted. Joint forces at the elbow are distributed between the ulnohumeral and radiocapitellar joints.

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Oleh: Misbahuddin Pembimbing: Dr. Mujaddid IdulHaq Sp. OT (K) Biomechanics of the Elbow
Stability of the elbow - static and dynamic constraints  3 primary static constraints Ulnohumeral articulation, the anterior bundle of the MCL the lateral collateral ligament (LCL) complex  4 Secondary constraints Radiocapitellar articulation, the common flexor tendon, the common extensor tendon, the capsule.  Dynamic stabilizers - Muscles that cross the elbow joint
Osteoarticular anatomy  The articular surfaces of the elbow joint distal humerus, the proximal ulna, proximal radius are The elbow -trochleogingylomoid joint hinged (ginglymoid) motion in flexion and extension at the ulnohumeral and radiocapitellar articulations radial (trochoid) motion in pronation and supination at the proximal radioulnar joint
Osseous stability - enhanced in flexion coronoid process locks into the coronoid fossa of the distal humerus radial head is contained in the radial fossa of the distal humerus Osseous stability - enhanced in extension the tip of the olecranon rotates into the olecranon fossa. The sublime tubercle is the attachment site for the anterior bundle of the MCL.
Capsuloligamentous anatomy  The static soft tissue stabilizers the anterior and posterior joint capsule the medial and LCL complexes. The collateral ligament complexes are medial and lateral capsular thickenings
The MCL complex  3 components: the anterior bundle or anterior MCL,  the posterior bundle,  the transverse ligament The origin of the MCL is at the anteroinferior surface of the medial epicondyle.
AMCL inserts on the anteromedial aspect of the coronoid process, the sublime tubercle. Provide significant stability against valgus force one of the primary static constraints of the elbow The anterior bundle - divided into anterior band posterior band
The transverse ligament Runs between the coronoid and the tip of the olecranon consists of horizontally oriented fibers that often cannot be separated from the capsule
The LCL complex  four components radial collateral ligament, the lateral ulnar collateral ligament, the annular ligament, the accessory collateral ligament The LCL complex originates along the inferior surface of the lateral epicondyle.
dynamic stabilization Muscles that cross the elbow joint  Four groups Elbow flexors, Elbow extensors, Forearm flexor-pronators, Forearm extensors.
 Flexors - biceps, brachialis, brachioradialis.  Extensor - The triceps, Anconeus (minor role)
ELBOW BIOMECHANIC Pronation-supination The radiocapitellar and proximal radioulnar joints The normal range of forearm rotation is 180 with pronation of 80 to 90 and supination of ~ 90 Most ADL can be accomplished with 100 of forearm rotation (50 of pronation and 50 of supination)
The normal axis of forearm rotation - the center of the radial head to the center of the distal ulna axis of rotation shifts slightly ulnar and volar during supination shifts radial and dorsal during pronation The radius moves proximally with pronation distally with supination
Forearm rotation - important role in stabilizing the elbow, especially when the elbow is moved passively. With passive flexion, the MCL deficient elbow is more stable in supination, whereas the LCL-deficient elbow is more stable in pronation in coronoid fractures that involve more than 50% of the coronoid with or without an intact MCL
Coronoid The coronoid process -key role in stabilization of the elbow.  ‘‘terrible triad,’’ elbow dislocation radial head and coronoid fractures. Fractures involving > 50% of the coronoid shows significantly increased varus-valgus laxity, even in the setting of repaired collateral ligaments The coronoid plays a significant role in posterolateral stability in combination with the radial head.
Soft tissues that attach to the base of the coronoid include Anteriorly- Insertion of the anterior capsule and brachialis Medial- insertion of the MCL.
Proximal radius The radial head is an important secondary valgus stabilizer of the elbow (30%) more important for valgus stability in the presence of MCL deficiency Radial head excision also increases varus-valgus Laxity and posterolateral rotatory instability, regardless of whether the collateral ligaments are intact
Soft tissue stabilization Medial collateral ligament complex AMCL is the primary constraint for valgus and posteromedial stability The anterior band of the AMCL - more vulnerable to valgus stress when the elbow is extended, The posterior band - more vulnerable when the elbow is flexed. Complete division causes valgus and internal rotatory instability throughout the complete arch of flexion with maximal valgus instability at 70 maximal rotational instability at 60
LCL complex The LCL is the primary constraint of external rotation and varus stress at the elbow. complete sectioning causes varus and posterolateral rotatory instability and posterior radial head subluxation The flexion axis of the elbow passes through the origin of theLCL so that there is uniform tension in the ligament throughout the arc of flexion.
damage to the LCLcomplex is the initial injury seen along the continuum of injuries resulting from elbow dislocation In Lateral surgical approaches to the elbow for radial head fixation or replacement. As long as the annular ligament is intact, the radial collateral ligament or the lateral ulnar collateral ligament can be cut and repaired without causing instability
Muscles Muscles that cross the elbow joint act as dynamic stabilizers as they compress the joint. Compression of the elbow joint by the muscles protects the soft tissue constraints. throwing an object can cause a valgus stress that is greater than the failure strength of the MCL. The flexor-pronator muscle group contracts during the throwing motion and provides dynamic stabilization to the medial aspect of the elbow, which protects the MCL from injury
Joint forces  significant compressive and shear forces at the elbow Loads across the elbow - distributed 43% across the ulnohumeral joint and 57% across the radiocapitellar joint Joint reaction forces vary with elbow position. Force transmission at the radiocapitellar joint is Greatest between 0 and 30 of flexion and is greater in pronation than in supination. elbow - extended, the overall force on the ulnohumeral joint is concentrated at the coronoid elbow - flexed, the force moves toward the olecranon
TERIMA KASIH

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Biomekanik cubiti mjd

  • 1. Oleh: Misbahuddin Pembimbing: Dr. Mujaddid IdulHaq Sp. OT (K) Biomechanics of the Elbow
  • 2. Stability of the elbow - static and dynamic constraints  3 primary static constraints Ulnohumeral articulation, the anterior bundle of the MCL the lateral collateral ligament (LCL) complex  4 Secondary constraints Radiocapitellar articulation, the common flexor tendon, the common extensor tendon, the capsule.  Dynamic stabilizers - Muscles that cross the elbow joint
  • 3. Osteoarticular anatomy  The articular surfaces of the elbow joint distal humerus, the proximal ulna, proximal radius are The elbow -trochleogingylomoid joint hinged (ginglymoid) motion in flexion and extension at the ulnohumeral and radiocapitellar articulations radial (trochoid) motion in pronation and supination at the proximal radioulnar joint
  • 4. Osseous stability - enhanced in flexion coronoid process locks into the coronoid fossa of the distal humerus radial head is contained in the radial fossa of the distal humerus Osseous stability - enhanced in extension the tip of the olecranon rotates into the olecranon fossa. The sublime tubercle is the attachment site for the anterior bundle of the MCL.
  • 5. Capsuloligamentous anatomy  The static soft tissue stabilizers the anterior and posterior joint capsule the medial and LCL complexes. The collateral ligament complexes are medial and lateral capsular thickenings
  • 6. The MCL complex  3 components: the anterior bundle or anterior MCL,  the posterior bundle,  the transverse ligament The origin of the MCL is at the anteroinferior surface of the medial epicondyle.
  • 7. AMCL inserts on the anteromedial aspect of the coronoid process, the sublime tubercle. Provide significant stability against valgus force one of the primary static constraints of the elbow The anterior bundle - divided into anterior band posterior band
  • 8. The transverse ligament Runs between the coronoid and the tip of the olecranon consists of horizontally oriented fibers that often cannot be separated from the capsule
  • 9. The LCL complex  four components radial collateral ligament, the lateral ulnar collateral ligament, the annular ligament, the accessory collateral ligament The LCL complex originates along the inferior surface of the lateral epicondyle.
  • 10. dynamic stabilization Muscles that cross the elbow joint  Four groups Elbow flexors, Elbow extensors, Forearm flexor-pronators, Forearm extensors.
  • 11.  Flexors - biceps, brachialis, brachioradialis.  Extensor - The triceps, Anconeus (minor role)
  • 12. ELBOW BIOMECHANIC Pronation-supination The radiocapitellar and proximal radioulnar joints The normal range of forearm rotation is 180 with pronation of 80 to 90 and supination of ~ 90 Most ADL can be accomplished with 100 of forearm rotation (50 of pronation and 50 of supination)
  • 13. The normal axis of forearm rotation - the center of the radial head to the center of the distal ulna axis of rotation shifts slightly ulnar and volar during supination shifts radial and dorsal during pronation The radius moves proximally with pronation distally with supination
  • 14. Forearm rotation - important role in stabilizing the elbow, especially when the elbow is moved passively. With passive flexion, the MCL deficient elbow is more stable in supination, whereas the LCL-deficient elbow is more stable in pronation in coronoid fractures that involve more than 50% of the coronoid with or without an intact MCL
  • 15. Coronoid The coronoid process -key role in stabilization of the elbow.  ‘‘terrible triad,’’ elbow dislocation radial head and coronoid fractures. Fractures involving > 50% of the coronoid shows significantly increased varus-valgus laxity, even in the setting of repaired collateral ligaments The coronoid plays a significant role in posterolateral stability in combination with the radial head.
  • 16. Soft tissues that attach to the base of the coronoid include Anteriorly- Insertion of the anterior capsule and brachialis Medial- insertion of the MCL.
  • 17. Proximal radius The radial head is an important secondary valgus stabilizer of the elbow (30%) more important for valgus stability in the presence of MCL deficiency Radial head excision also increases varus-valgus Laxity and posterolateral rotatory instability, regardless of whether the collateral ligaments are intact
  • 18. Soft tissue stabilization Medial collateral ligament complex AMCL is the primary constraint for valgus and posteromedial stability The anterior band of the AMCL - more vulnerable to valgus stress when the elbow is extended, The posterior band - more vulnerable when the elbow is flexed. Complete division causes valgus and internal rotatory instability throughout the complete arch of flexion with maximal valgus instability at 70 maximal rotational instability at 60
  • 19. LCL complex The LCL is the primary constraint of external rotation and varus stress at the elbow. complete sectioning causes varus and posterolateral rotatory instability and posterior radial head subluxation The flexion axis of the elbow passes through the origin of theLCL so that there is uniform tension in the ligament throughout the arc of flexion.
  • 20. damage to the LCLcomplex is the initial injury seen along the continuum of injuries resulting from elbow dislocation In Lateral surgical approaches to the elbow for radial head fixation or replacement. As long as the annular ligament is intact, the radial collateral ligament or the lateral ulnar collateral ligament can be cut and repaired without causing instability
  • 21. Muscles Muscles that cross the elbow joint act as dynamic stabilizers as they compress the joint. Compression of the elbow joint by the muscles protects the soft tissue constraints. throwing an object can cause a valgus stress that is greater than the failure strength of the MCL. The flexor-pronator muscle group contracts during the throwing motion and provides dynamic stabilization to the medial aspect of the elbow, which protects the MCL from injury
  • 22. Joint forces  significant compressive and shear forces at the elbow Loads across the elbow - distributed 43% across the ulnohumeral joint and 57% across the radiocapitellar joint Joint reaction forces vary with elbow position. Force transmission at the radiocapitellar joint is Greatest between 0 and 30 of flexion and is greater in pronation than in supination. elbow - extended, the overall force on the ulnohumeral joint is concentrated at the coronoid elbow - flexed, the force moves toward the olecranon