Pathomechanics of Common Shoulder Injuries

Transcription

1 Pathomechanics of Common Shoulder Injuries Kevin E. Wilk,, DPT Birmingham, Alabama, USA kevinwilk.. com

2 Shoulder Injuries in Sports Introduction Shoulder injuries are common in sports» Collision sports football, wrestling, skiing College football 4 th most common injured joint Kaplan et al: AJSM 05 Professional Football NFL Combine 5 th AC joint sprains 9 th GH joint instability Brophy et al:med Sci Sports 07» Contact sports soccer, basketball, Shoulder injuries occur in various sports Shoulder Injuries in Sports Contact Sports Collision Sports Contact Sports Shoulder Injuries in Sports Contact Sports Bankart Lesion Detachment of capsulolabral complex increases translation by nearly 200% Lazarus: JBJS 96 The Overhead Thrower Introduction Shoulder & elbow injuries are common in baseball In professional baseball 28 % of all injuries occur to the shoulder joint 22 % of all injuries occur to elbow joint Length of injury time is increasing days on the disabled list days Conte et al: Am J Spts Med 01 In youth baseball 50 % of players (9-14) complained of elbow or shldr pain Lyman et al: Am J Spts Med 02 Number of injuries increasing & age decreasing UCL injuries Petty, Andrews, Fleisig: : AJSM 04

3 The Overhead Thrower Introduction Biomechanics of the Shoulder Joint Complex During Throwing The Thrower s s Shoulder Excessive Motion especially External Rotation Requires stability Inherent hyper-laxity Allows tremendous mobility Fine line: Too loose & just right!!! Paradox of the Thrower s s Shoulder Biomechanics Laboratory Set-Up 85 x 30 x 15 ft. Indoor Laboratory Loose enough to throw, but stable enough to prevent symptoms Wilk: AJSM 02

4 Biomechanics Laboratory Equipment Motion Analysis System (Motion Analysis Corp.) 8 high-speed cameras (240 Hz) Automatic 3D digitizing Reflective markers Pitching Biomechanics : Process Marker Placement 21 total (4 on hat) Acromion Lateral Epicondyle Greater Trochanter Distal Radius (only on pitching hand) Distal Ulna Distal 3 rd Metacarpal (only on pitching hand) 2 in. Superior to Proximal Fibula Lateral Malleolus Distal 3 rd Metatarsal Biomechanics Laboratory Equipment High-Speed Video (Vision Research Inc.)» 450 frames/second Pitching Biomechanics : Process Scientific Feedback Written Report High-Speed Video Unlimited Support Pitching Biomechanics : Introduction Kinetic Chain» Coordinated activation of body segments Pitching Biomechanics : Phases of Pitching 1. Wind-Up 2. Stride 3. Arm Cocking Six Phases 4. Arm Acceleration 5. Arm Deceleration 6. Follow-Through

5 Pitching Biomechanics : Phases of Pitching Windup Low force/torque on shoulder & elbow Stride Pitching Biomechanics : Stride Foot Contact Lead Leg Stride Foot Contact Stride Direction Stride Length & Knee Angle Foot Contact 0 in Shoulder: Abduction = 90 Ext. Rotation = 60 % Height 12 in 5 in Pitching Biomechanics : Stride Foot Contact Upper Arm Stride Foot Contact Shoulder External Rotation Shoulder Abduction Pitching Biomechanics : Stride Foot Contact Upper Arm Stride Foot Contact Shoulder Horizontal Abduction Elbow Flexion

6 Pitching Biomechanics : Phases of Pitching Arm Cocking Pitching Biomechanics : Arm Cocking Trunk Rotation: Stride Foot Contact to MER Pelvis Max. Velocity = /sec 19-39% after FC Upper Trunk Max. Velocity = 1,077 1,229 /sec 40-56% after FC From Stride Foot Contact to Maximum Shoulder External Rotation Pitching Biomechanics : MER Upper Arm MER Maximum Elbow Flexion 9 1 Maximum External Rotation Body rotates forward as the arm rotates backwards Arm Cocking Maximum External Rotation = 145> Arm Acceleration Arm Acceleration How fast is 7500 /s? Internal Rotation Velocity = 7500 /s Fastest measured human joint motion If the arm maintained that peak speed for 1 second, it would make about 20 full revolutions!

7 Pitching Biomechanics : Arm Acceleration Pitching Biomechanics : Ball Release Upper & Lower Body Ball Release Shoulder Abduction & Lateral Trunk Tilt Hip Flexion & Knee Angle Elbow Max. Extension Velocity 2,224 2,684 /sec Shoulder Max. Internal Rotation Velocity 6,688 8,352 /sec Large deceleration forces on shoulder Maximum Internal Rotation = 0 Arm Deceleration Shoulder resists and controls horizontal adduction Large body parts dissipate energy from arm Follow-Through Balance is necessary for fielding position Pathomechanics Max. ER Two critical instants Ball Release 40 Max. ER Pathomechanics Shoulder» Abduction = 90 º» Ext Rotation = 180 º» Anterior Force = 400 N» Int Rot Torque = 67 Nm (equivalent to 40 lbs. pulling down on the hand)

8 Biomechanical Evaluations: Examples Faults Internal Impingement What is it?! Occurs during abduction & excessive external rotation! Late cocking during pitching Foot Contact Foot Contact Pelvis Rotation Ball Release! Supraspinatus / Infraspinatus rubs on the posterosuperior glenoid rim & labrum! Results in fraying of cuff and glenoid labrum inflammation Andrews: Tech Orthop 88 Walch: : JSES 91 Andrews, Wilk,, Reed et al: Sprg Trn asymptomatic professional baseball pitchers in spring training MRI of glenohumeral joint 28/31 (90 %) abnormal glenoid labrum 27/31 (87 %) abnormal rotator cuff appearance 12/31 (39%) humeral head changes All pitchers were pain-free at time of study Jost, Zumstein,, Gerber: CORR competitive Swiss handball players MRI performed both shoulders 93% throwing abnormal MRI - but only 37% were symptomatic Partial rotator cuff tears most common Superolateral osteochondral of humeral head defects present Evaluation critical to diagnosis not just MRI External Rotation " Performance The Shoulder Joint in Tennis External Rotation Forward Trunk Time Elbow Vel Time Shoulder Vel Low Velocity 166 ± 9 29 ± ± 2 % 104 ± 2 % High Velocity 179 ± 8 37 ± 7 91 ± 2 % 102 ± 2 %

9 Shoulder Injuries in Tennis Goals of Presentations Physical characteristics of tennis players Discuss some research in tennis Discuss specific injuries & Rx» Impingement» Scapular dysfunction» Biceps pain The Serve KINEMATIC VARIABLES GH ABD: MAX GH ER: GH IR 7550 /s 4950 /s 1514 /s ELB FLXN ELBOW EXT: 2340 /s 1760 /s 1700 /s FLEISIG ET AL, 96, SHAPIRO & STINE, 92

10 Comparison Baseball Throwing to Tennis Serve Kinematics Joint Kinematics Tennis Serve:! 83 deg abduction! 1,074-2,300 deg/sec! ER to 154 degrees Shapiro: Unpub 92 Dillman: USTA 91 Baseball Throwing:! deg abduction! 7250 deg/sec accel.! 0.5 x BW late cocking! ER to 175 deg.! % BW decel phase! Late cocking ball 0.03sec Fleisig:AJSM 95 Wilk: Spts Med Arthro 00 The Forehand The Backhand

11 Injuries in Tennis Introduction Repetitive overuse UE injuries:» Tendinitis» Muscle strains» SLAP lesions» Tendonosis» Epicondylitis» Stress fractures Overuse Trauma Shoulder injuries:» Impingements Injuries in Tennis Upper Extremity Injuries Impingements Internal impingement Subacromial impingement» Glenoid labrum SLAP lesions» Tendinitis» Tendonosis» Partial thickness tears PASTA lesions PAINT lesions The Biomechanics of the Golf Swing

12 Maximum Velocity During Swing (Degrees Per Second) PGA LPGA Hip turn Shoulder turn Arm velocity Club velocity THE GOLF SWING Set-up position Backswing phase Downswing phase» Forward swing» Acceleration Follow-through phase SET-UP POSITION Important phase of golf swing Align golfer with target Establish postural balance» Knee flexion » Wt distribution 50-60% back foot» Primary spinal angle (trunk flexion)» Secondary spinal angle (lateral R bend) IMPROPER SET-UP POSITION Very common among amateurs Most common not using hip- hinge positions» primary spinal angle formed by spine Improper grip pressure» excessive grip pressure Poor postural balance

13 BACKSWING PHASE Purpose of backswing is to position & align the golfer s s hub of rotation to execute a powerful swing Linear smooth movement Trunk rotation Backswing complete when club is parallel (near) to ground BACKSWING PHASE Right shoulder abducts & ER Left shoulder adducts & IR Scapula (L) protracts, elevates & upward rotates» Right shoulder ER » Left shoulder IR Proper shoulder turn Pelvic rotation of at least 45 0 Critical, but unnatural movement IMPROPER BACKSWING PHASE Most common flaw lateral movements of hips & legs Move laterally instead of rotating within base of support Lack of trunk rotation, (poor flexibility) shoulder mobility» Lead shoulder: limited adduction & IR» Back shoulder: limited ER (flying elbow!!!!) THE DOWNSWING PHASE Forward swing and acceleration Initiated by hip turn & wt. transfer Centrifugal force & angular momentum to generate clubhead speed Clubhead speed: /sec (100 mph) Pelvic rotation speed: /sec Arm speed: /sec Move laterally instead of rotating within base of support Lack of trunk rotation, (inflexibility): greater shoulder mobility

14 THE DOWNSWING PHASE Impact occurs for sec.» Highest incidence of injuries(50%) Highest muscle activity:» Right side: pectoralis major, subscapularis, latissimus dorsi» Left side: latissimus dorsi & subscapularis,, posterior muscles IMPROPER DOWNSWING PHASE Loss of swing path due to weight shifting» Lost swing in backswing Amateurs generate 50-80% greater spine forces & 50% greater EMG Yet professionals generate 34% greater clubhead speed THE FOLLOW-THROUGH PHASE Body gradually decelerates rotary movement through eccentric contractions Shoulder function as backswing (reverse)» Left shldr: abd, horiz abd, ER» Right shldr: horiz add, IR Arms reach shoulder level elbows flex Subscapularis, pect major, & lats Second highest incidence of injuries (30%) PHYSICAL FACTORS THAT CAN LIMIT SWING Shoulders - tightness which limits shoulder turn, inability to maintain swing plane» Lead shoulder: limited Horz add, IR then 55 deg abd» Back shoulder: limited ER at 45 deg abduction then horiz add with IR Low back - tightness which limits proper set-up, limits rotation Hip/pelvis - weakness & tightness limits rotation, posture swing plane PHYSICAL FACTORS THAT CAN LIMIT SWING Evaluation ROM & flexibility Strength test Golf functional test Will your body allow you to swing properly & effectively

15 Treat Kinetic Chain The Females Throwing Shoulder Windmill Softball Pitch 4 Phases of Pitch #Windup #Stride #Delivery #Follow through Barrentine, et al JOSPT

16 Windmill Softball Pitch Biomechanical Analysis Wind-up phase» Arm in hyperextension» Foot push-offs» Initiate forward translation of body Windmill Softball Pitch Stride phase» Emphasis on forward translation of body» Excessive shoulder flexion (180 0 )» Linear velocity of hips Biomechanical Analysis Windmill Softball Pitch Biomechanical Analysis Delivery phase» Trunk rotation 430 deg/sec» Torso rotation 650 deg/sec» Arm flexion & IR 5,000 deg/sec #*Shoulder flex 3x BW #*Superior forces 98% BW Windmill Softball Pitch Follow through phase» Gradually dissipate forces» Max shoulder post force 59% BW» Elbow compression force 56% BW Biomechanical Analysis Windmill Softball Pitch EMG Analysis Maffet: : AJSM 97 From 6 to 3 o clocko» Infraspinatus 93% MVIC» Supraspinatus 78% MVIC» Ant. Deltoid 38% MVIC Windmill Softball Pitch EMG Analysis Maffet: : AJSM 97 From 3 to 12 o clocko» Posterior deltoid 102%» Teres minor 87%» Infraspinatus 87%

17 Windmill Softball Pitch EMG Analysis Maffet: : AJSM 97 From 12 to 9 o clocko» Subscapularis 81%» Pectoralis major 575» Posterior deltoid 52% Windmill Softball Pitch EMG Analysis Maffet: : AJSM 97 From 9 o clock o to ball release» Pect major 76%» Subscapularis 75%» Serratus anterior 61% Shoulder Injuries in Sports Conclusions Shoulder injuries are common in sports Numerous types of lesions Understanding the pathomechanics assists in diagnosis & treatment Also may assist in prevention programs Recognition is key to proper treatment Danke