Elbow instability Flashcards
Medial UCL instability- valgus instability Posterolateral instability Valgus extension overhead instability
1
Q
What leads to valgus instability?
A
- Attenutation or rupture of the medial ulnar collateral ligament
- seen in
- overhead athletes who place significant stree on elbows
- uncommon in skletally immature
2
Q
What is the mechanism of valgus instability?
A
-
Acute trauma
- assoc with dislocation
-
Overuse injury
- micro trauma from repititive valgus stress -> ruputure of the anterior band of medial UCL
- baseball pitchers put hige valgus stress in elbow in late cocking, early acceleration phase of throwing
- elbow valgus load increases with poor trhwoing mechanics
- valgus load highest in accleration phase
-
Iatrogenic
- excessive oelcranon resection places the MCL at risk
3
Q
Name assoc conditions of valgus instability?
A
- traction related ulnar neuritis
- olecranon posteriomedial impingement
- elbow arthritis
4
Q
Describe the anatomy of the medial collateral ligament of the elbow?
A
- aka Ulnae Collateral Ligament
- 3 components
-
anterior oblique
- strongest, most sig stabiliser to valgus stress
- course medial epicondyle to sublime tubercle
- nearly isometric
- post band is tight in flexion, **ant band is tight in extension **
-
posterior oblique
- demonstrates the greatest change in tension form flexion to extension
- tighter in flexion
-
Transverse ligament
- no contribution to stability
5
Q
What is the presentation of a pt with valgus instability?
A
- Acute injury- pop then drop in velocity
-
Decrease in throwing preformance
- loss velocity, loss control
-
pain
- medial or posterior
- ulnar nerve symptoms
O/E
- Medial tenderness near MCL origin
-
valgus stres test
- elbow at 20-30o unlocks olecranon, ER rotae humerus, apply valgus stree= 50% sensitive
-
moving stress test
- foream supinated, elbow flexed at 90o apply valgus stress by pullingon thumb put elow thru full arc flexion/extension. positiev is pain at 70-120 o
- http://www.orthobullets.com/video/view?id=535
6
Q
What is seen on imaging of valgus instability?
A
- xary - ap and lateral often normal
-
gravity stress
- medial joint line opening > 3mm
-
gravity stress
- MRI
- thickened ligament. calcifications,tears
- MR-arthrogram diagnostic
- can dx full thickness tears/partial undersuface tears
- look for T sign with contrast extravasation- see pic
7
Q
What is the tx of valgus instability?
A
Non operative
-
Rest and physio
- 1st line of tx
- 6wks rest from throwing
- outcome 42% return to preinjury level of sporting activity at an av of 24 wks
Operative
-
MCL anterior band ligament reconstruction
- outcomes 90% return to preinjury level of throwing
- humeral docking technique asso iwth better pt outcomes and less complx cf fig ure of 8 fixation
- humeral docking biomechanically stronger than fig of 8 and interference screw fixation
8
Q
DEscribe the technique of mcl reconstruction in elbow
A
- medial approach
- approach muscle splitting approach to decrease morbidity to flexor -pronator mass
- insitu ulna neve decompression with transposition if preop symptoms
-
docking teachnique
- graft limbs gracilis/palmaris longus are tensioned thru a single humeral docking tunnel
- sutured limbs then passed through 2 bone puncture and sutures over bony bridge on medial epicondyle
- http://www.orthobullets.com/video/view?id=472
- Endo-button thru the ulna
-
post op
- early active wrist , elbow and shoulder rom
- strengthening exercises beginning 4-6 wks post op
- avoid valgus stress until 4 months post op
- progressive throwing regime at 4 months
- return competetive throw at 9-12 months
9
Q
What are the complications of valgus instability?
A
- Ulna n injury
-
Medial antebrachial cutaneous nerve injury
- nerve is present at distal apect of incision
- Fx of ulna or medial epicondyle
- elbow stiffness
- inability to reagin preinjury level of throwing ability
10
Q
What is posterolateral elbow rotatory instability?
A
- Traumatic varus stress may result in isolated injury but most injuries involve a spectrum of pathology following elbow dislocation
11
Q
Describe the mechanism of posterolateral elbow rotatory instability?
A
-
Traumatic
- most common
- combo of forearm supination, axial loading, valgus ( posterolat) stress and elbow extension-> post subluxation of radial head and rotation of semilunar notch away from trochlea
-
Iatrogenic
- from arthroscopic or open proceedures invovling lateral elbow
- arthroscopic should keep anterior to equator of radial head
-
chronic attenuation
- 2ary to chronic cubital varus malunion
12
Q
Describe the anatomy of lateral collateral ligament?
A
- 4 components
- Lateral ( radial ) collateral lig
- accessory lateral collateral lig
- annular ligament
-
lateral ulnar collateral lig (LUCL)
- primary stabiliser to varus & ER stress
- ulna portion of the lateral radial collateral lig
- originates lateral humerla condyle and inserts tubercle of supinator crest of ulna
13
Q
Describe the presentation of posterolateral elbow rotatory instability?
A
- Pain
- mechanical locking clicking/catching with elbow extended- pushing off from chair
O/E
- Varus instability
- tenderness over LUCL
-
Lateral pivot shift test
- supine. affected arm over head. forearm is supinated and valgus stress is applied whilr flexing elbow
- http://www.orthobullets.com/video/view?id=1040
- Chair rise test
14
Q
What is the tx of posteriolateral instability?
A
Non operative
- Acute reduction followed by immobilisation 5-7 days
- for acute dislocations
- 90o flexion then
- pronated if LCL disrupted but MCL intact
- supinate if MCL disrupted and LCL intact
Operative
-
ORIF and ligament repair for
- acute instability maybe tx with repair
- osteochondral fx/ soft tissue prevent reduction
- complex dislocation + fx
-
LUCL reconstruction
- for posterior lateral rotatoty instability
15
Q
What would be the technique for LUCL reconstruction?
A
- Autograft ( palmaris longus) vs allograft
- tendo graft tied to itself over lateral colum after placing thru tunnel in supinator creast then weaving thu Y tunnel configuration in humerus
- critical that graft covers 25% if radial head to create a sling
- graft secured with arm in neutral rotation and 45o flexion
- _post op _
- protected from varus stress and shoulder adduction by a locked hinge brace
- early rom encouraged
- keep forearm in pronation during rom until 6 wks
