mark clatworthy orthopaedic surgeon knee specialist middlemore hospital
TRANSCRIPT
KNEE INJURIES WORKSHOP
Mark ClatworthyOrthopaedic Surgeon
Knee SpecialistMiddlemore Hospital
Overview Anatomy Refresher
How to diagnose and treat a meniscal tear, a ligament rupture and a patella dislocation
When should I take x rays of the knee and what should I take?
Practical on examination of the knee
Meniscal Tear
Mechanism of Injury
Typically a twisting injury on a loaded knee Often sudden pain Knee swells – variable time frame Mechanical symptoms – catching, locking,
clunking Can give a feeling of instability
Examination Findings
Effusion Springy block to extension if bucket
handle Focal joint line tenderness Pain on meniscal grinding Pain on loading and twisting
the knee
EffusionTense effusion is easily seen,
Moderate effusion – patella tapMild effusion - patella sweep
Meniscal Grind Test
Locked knee
Physical block
In young patient needs urgent meniscal repair
Don’t send to physiotherapistUrgent referral to orthopaedic surgeonWe will see the patient that week
Differential Diagnosis
Articular cartilage injury – unstable flap
Loose body
Stir up Osteoarthritis
Collateral Ligament Injury
Treatment Locked knee refer
RICE
Symptoms will typically improve over a 6 week period then plateau
Refer if persistent pain or mechanical symptoms
ACL Injury
History taking key to diagnosis
Acutely injured knees are painful and swollen making the examination difficult
The diagnosis normally lies in the history
ACL Injury Mechanism of injury
Normally a side stepping or pivoting manoeuver or an awkward landing
Often a non contact injury
The posterolateral knee subluxes
Patient will feel a pop and the knee gave way
ACL Rupture Patient usually presents with a
haemarthrosis
Knee may fell unstable with any twisting activity
Difficulty weightbearing due to bone bruising
The knee subluxes posterolaterally thus this area is usually tender
ACL Rupture
Patients often present with a fixed flexion deformity. Initially this is due to bone bruising.
A bucket handle tear typically occurs only with multiple giving way episodes
Examination Findings
Must examine both knees. Large variation laxity
Fixed flexion deformity, reduced flexion
Quads Wasting
Occurs very early. Up to 5% loss of muscle bulk a dayVery sensitive for a knee injury but not specific for a diagnosis
Ligament Examination The grading is determined by the increase in
laxity compared to the normal contralateral knee
AOSSM ClassificationGrade 1 - 0 – 5 mm increase in laxity Grade 2 - 5 – 10 mm increase in laxityGrade 3 - >10mm
ACL Examination Lachmann - anterior translation tibia
ACL Examination Lachmann – Big leg, small hands
ACL ExaminationAnterior drawer decreased by posterior horn of the menisci – less positive than
Lachmann
ACL Examination Pivot shift test- reproduces the sensation of
giving way. Lateral compartment subluxes
Exclude PCL Injury
Drop back seen with knee at 90°
Compare withother side
PCL Examination Posterior drawer
Acute Treatment RICE
Do not immobilize. No knee brace required if no collateral ligament injury.
Need to start on quads and knee extension exercises immediately
Can weightbear as tolerated Refer orthopaedic surgeon
and physio
Collateral Ligament Injuries
Mechanism of injuryValgus force – rupture MCLVarus force – rupture LCL
Patient presents with pain and instability with coronal movement
Collateral Ligament Examination
Palpate the ligament first.
MCL – Arises - medial femoral epicondyle Inserts – 6 - 8cm distally on the tibia
LCL - Arises from the lateral epicondyleInserts into the fibula
The LCL thus has more laxity than the MCL
Can palpated as a cord like structure when the knee is placed in a figure 4 position
Collateral Ligament Examination
Acute Treatment RICE
Do not immobilize. Short ROM brace if Grade II or III
Need to start on quads and ROM exercises immediately
Can weightbear as tolerated if knee feels stable
Refer orthopaedic surgeon and physio
Patella Dislocation
Mechanism of InjuryTypically twisting injury on a flexed knee or a direct blow
Patella may dislocate and stay there or self reduce
Examination findings
Haemarthrosis
Medial retinacular tenderness
Patella apprehension sign
Patella apprehension test
Acute Treatment Reduce dislocation RICE Aspirate if tense effusion Ensure there is no osteochondral fragment Immobilise in Zimmer splint – NO CASTS Refer to orthopaedic surgeon Refer to physio for static quads and straight
leg raising exercises Can weightbear as tolerated
Who should I X Ray?
Patients with a knee effusion
Unable to weight bear
Ligamentous injury
Patella dislocation
What X Ray’s should I take
Weight bearing AP
45º weight bearing PA
Lateral
Skyline
AP Pelvis if unsure about hip
Weight bearing X Rays Weight bearing X rays are critical
45° Weight bearing PA
Skyline patella
Weight Bearing X Rays Mandatory for ACC knee injuries
Orthopaedic surgeon can not get an ACC funded MRI scan without them
So if patient able to weightbear always order weightbearing knee X rays
Who should I refer immediately ?
Multi ligament knees
ACL & PCL avulsions
Locked knees
Patella dislocations with osteochondral fragments
Who should be referred to an Orthopaedic Surgeon?
All patients with suspicion of a- ligament tear- meniscal injury- patella dislocation
Who should be referred to the physiotherapists?
Patella dislocations
Cruciate ligament injuries
Collateral ligament injuries
No meniscal tears
Who should I aspirate? Only those with painful tense haemarthrosis. I aspirate very few Aspirate superio-lateral with a large >= 16
gauge angiocath.Inject Xylocaine with adrenalineExamine the knee after 5 minutes
If unsure refer
KNEE EXAMINATION DEMONSTRATION
http://www.acc.co.nz/for-providers/clinical-best-practice/practical-workshops/WPC090892