The Upper Limb. Elbow Rotation 4/25/18. Dr Peter Friis

Transcription

1 The Upper Limb Dr Peter Friis Elbow Rotation Depending upon the sport, the elbow moves through an arc of approximately 75⁰ to 100⁰ in about 20 to 35 msec. The resultant angular velocity is between 1185 and 2320 deg/sec. The estimated internal force in the medial ulnar collateral ligament (MUCL) is 290 N. 1

2 Cadaver studies evaluating the isolated load-bearing potential of the MUCL have calculated an ultimate failure load of 34 Nm and a tensile failure load of the bone-ligament complex of 261 N Because the measured forces in actual activities are higher than the calculated capabilities of the ligaments and bones, other factors besides the ligament constraints must be operative to regulate the loads in order to keep the elbow from being injured on every throw or serve. Optimize efficient proximal segment activation in order to minimize the need for high force generation in the distal segments. Arm in an extended position increases bony contribution to stability and decreases maximum load on the MUCL 2

3 Elbow Dislocation Magnetic Resonance Imaging Findings in Acute Elbow Dislocation: Insight Into Mechanism Joseph J. Schreiber, MD, Hollis G. Potter, MD, Russell F. Warren, MD, Robert N. Hotchkiss, MD, Aaron Daluiski, MD dislocations Demonstrated that most elbow dislocations are the result of a hyperphysiologic valgus moment occurring to an extended elbow. Elbow Dislocation Simple dislocations are described by the direction of the dislocated ulna relative to the humerus. 3

4 Why does the capsule not get stuck in the joint Small articular muscles radiate from the triceps brachii muscle and the brachial muscle. These muscles maintain sufficient tension on the capsule Joint Capsule and Ligaments 4

5 lateral side of the proximal ulna. Posterolateral Rotatory Instability 5

6 AMCL avulsion Safely permitting early range of motion after a destabilizing injury to the elbow is believed to optimize return of function. However, the range-of-motion exercises must be balanced against the risk of re-dislocation or subluxation. 6

7 Complications of Elbow Dislocation In one study, almost all patients (96 %) had a fracture after elbow dislocation, although only 62 % of those fractures were seen on plain X rays. The most common anatomical fracture location was the coronoid process of the ulna, with 60 % of the patients with dislocations having a fracture in this site. 7

8 The second most common anatomical location of the fracture was the radial head, which was fractured in 54 % of patients with dislocation. The Terrible Triad History of previous dislocation may result in potential loose bodies from osteochondral fractures episodes of locking? Recent Xrays and Scans? Preventative rehab? 8

9 Overuse Injuries of the Elbow Tennis Elbow Golfer s Elbow Cozen s Test and Modification for Tennis Elbow evaluation. 9

10 Modification for Tennis Elbow evaluation. Reverse Squeeze Olecranon Bursitis 10

11 Ulnar Nerve Ulnar Neuritis.. Anterior Elbow Pain Distal Biceps Acute= Male (40yrs+) sudden eccentric load Pain is worse with resisted supination 11

12 More soup please Think supination Assessment of Chronic Elbow Pain Postural Asymmetry ROM Increase Carry Angle Shoulder IR loss > 25⁰ Weak scapular stabilizers More Valgus = Increase Carry Angle 5-15⁰ considered normal 30⁰ can usually be tolerated 12

13 Supracondylar Fractures Gunstock Deformity Range of Motion 13

14 Dropped elbow term for the elbow position below the level of the shoulder Interactive moments are moments at joints that are created by motion and position of adjacent segments. Maximum shoulder internal rotation force to rotate the arm is developed by the interactive moment developed by trunk rotation. Accuracy of ball throwing is related to the interactive moment at the wrist produced by shoulder movement. Varus Acceleration is protective against valgus load at the elbow It is primarily developed by the interactive moment generated by shoulder internal rotation. 14

15 Morgan (2002) showed that 20 out of 20 consecutive professional baseball pitchers with elbow symptoms were found to have glenohumeral internal rotation deficit (GIRD) of greater than 25⁰, and that correction of this deficit correlated with relief of symptoms. Reduced internal rotation Medial Border Prominence Side to side difference of greater than 25⁰ THE KINETIC CHAIN Pre-programmed muscle activations that position the body to withstand the forces of activity and create the proximal stability for distal mobility. Anticipatory Postural Adjustments (APAs) 15

16 A result of the activations and interactive moments, is a proximal to distal development of force and motion that includes core activation. Between 63% and 74% of the kinetic energy and force delivered to the hand was developed by the hip/trunk or shoulder segments in tennis players Considerations for the athlete returning from elbow injury. Consider also for preparticipation screen for throwing athletes. Hip flexibility & strength Scapular dyskinesis GIRD Elbow ROM 16

17 Mechanism and History of Trauma Scaphoid fractures can often be missed.. 17

18 18

19 Stenar Lesion 19

20 50% of sports-related hand injuries involve the fingers Dorsal finger PIP joint dislocations are typically due to a sports-related high-speed force to the distal finger, which, in turn, causes axial stress and hyperextension. Volar finger PIP joint dislocations are extremely uncommon. They occur when a longitudinal blow to a moderately flexed middle phalanx causes disruption of a collateral ligament and partial avulsion of the volar plate. They are nearly always accompanied by an injury to the central slip of the extensor tendons 20