Download Knee Injuries

Knee Injuries
General Principles
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If the patient has heard or felt a “pop” in the knee and there is a haemarthrosis,
there is a cruciate ligament tear until proven otherwise
If there is any swelling, ask how quickly it developed
o Haemarthroses develop quickly (less than 2 hours)
o Swelling that develops overnight is less significant
Some would advocate not aspirating knees (except in the case of septic arthritis)
in A&E for the following reasons:
o Infection risk [some orthopaedic surgeons prefer to do it themselves
under the more aseptic conditions in the operating theatre]
o A haemarthrosis aspirated to relieve pain may re-accumulate
Fat globules in blood coming from a knee usually indicate a fracture, although in
young people and children with pre-patella wounds this isn’t always the case
Unless there is a fracture or gross ligamentous instability, it is usually impossible
to make an accurate diagnosis in A&E
Following an injury, the knee is usually too painful and swollen to assess
accurately [if it is not, there is probably not a lot wrong!]
Physiotherapy referral allows reassessment of the knee as pain and swelling settles
Quadriceps exercises [knee advice sheet] should be encouraged in all patients with
mild to moderate knee injuries as wasting can occur very quickly leading to
instability
Indications for Knee X-rays - Ottawa Knee Rules
X-rays are required if any of the following apply:
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Aged 55 years or older
Tenderness at the head of the fibula
Isolated tenderness of the patella
Inability to flex to 90 degrees
Inability to weight bear both immediately and in A&E (4 steps)
Management Principles
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Immediate orthopaedic referral:
o Acutely locked knee
o Obviously unstable knee
o Tibial plateau fractures
o Patella fractures
Home with knee advice, tubigrip, crutches & no follow up:
o Able to walk
o Minimal swelling
o No instability
Home with knee advice, tubigrip, crutches & physiotherapy follow up:
o Remainder
Injuries to the Extensor Apparatus
Rupture of the Quadriceps Insertion
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Sudden pain above the patella
Occasionally a palpable gap in the tendon
SLR is still possible in partial rupture & can be treated in a POP cylinder
Complete rupture requires surgical repair
Stellate Fracture of the Patella
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Due to a direct blow e.g. fall on to the knee
Unable to SLR
Undisplaced fractures can be managed in a POP cylinder following aspiration of
the haemarthrosis
Displaced fractured require excision of the patella
Transverse Fracture of the Patella
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The patella is cracked across the femoral condyles by contraction of the
quadricpes
The quadriceps tendon is also torn
Unable to SLR
Repair with wires or excise if comminuted
Rupture of the Ligamentum Patellae
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Sudden pain below the patella
High riding patella
Occasionally a palpable gap in the tendon
Lower pole of the patella may be avulsed
Surgical repair is required
Avulsion of the Tibial Tuberosity
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Injury of childhood
Osgood Schlater’s Disease
Depending on severity consider immobilisation in a bandage or plaster
Dislocation of the Patella
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Lateral impact to the knee with twisting
The knee is held flexed with the patella displaced laterally
Reduces with knee extension & medial levering of the patella under entonox
X-ray prior to reduction is not usually required
Treat in a POP cylinder or a cricket pad splint
Injuries in the Lateral Plane
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Medial Collateral Ligament Injury
o Valgus strain
o Diffuse medial tenderness
o Complete tears with obvious laxity should be referred for repair
o Otherwise arrange physiotherapy
Lateral Collateral Ligament Injury
o Varus strain
o Diffuse lateral tenderness
o Complete tears with obvious laxity should be referred for repair
o Otherwise arrange physiotherapy
Tibial plateau fracture
o Fall onto the knee or from a great height
o The adjacent femoral condyle crushes the underlying tibial plateau
o Undisplaced tibial plateau fractures can be very subtle:
 Check the entire tibial cortex, not just the plateau
 Check for lipohaemarthrosis on the lateral view.
Injuries in the Anteroposterior Plane
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Cruciate Ligament Injury
o Often a skiing or football injury
o Most have a haemarthrosis, which may require aspiration
o Associated with medial collateral ligament & meniscal injury
(O’Donaghue’s Triad)
o Avulsion fractures of the tibial spine may require ORIF
o Stability is often difficult to assess in the acute situation
o Complete tears with obvious laxity should be referred for repair
o Otherwise arrange physiotherapy
Rotational Injuries
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Medial Meniscal Injury
o Fall with the knee semi-flexed & externally rotated
o Pain and medial joint line tenderness
o Mechanically locked knees should be referred immediately for
arthroscopy [some “locked” knees can be straightened after analgesia]
o Otherwise arrange physiotherapy
Lateral Meniscal Injury
o Much less common
o Fall with the knee semi-flexed & internally rotated
o Pain and lateral joint line tenderness
o Mechanically locked knees should be referred immediately for
arthroscopy [some “locked” knees can be straightened after analgesia]
o Otherwise arrange physiotherapy
Rotational Sprain
o Common
o Pain & tenderness over the joint line
o Sometimes there may even be an effusion but never locking
o Otherwise arrange physiotherapy