Orthopaedic Emergencies 307

INJURIES TO THE LOWER FEMUR, KNEE AND UPPER TIBIA

(ii) A twisting injury will damage one of the menisci, usually the

medial.

(iii) Combinations may be seen. A severe, twisting lateral blow to the

knee, e.g. from a car bumper, will rupture the medial collateral

ligament, tear the medial meniscus, and rupture the anterior

cruciate ligament (O’Donoghue’s ‘unhappy triad’)

(a) this may result in a tense haemarthrosis, in the absence of a

fracture.

3 Always undress the patient and examine on a trolley. Include the hip and
spine, as the pain may be referred particularly in children. Perform the
following in every knee examination:
(i) Observe the size and extent of knee swelling and the location of
bruising.
(ii) Look at the position of the knee
(a) meniscal tears may result in ‘locking’ of the knee with
inability to fully extend the knee.
(iii) Palpate the knee to elicit the area of maximum pain.
(iv) Assess the medial and lateral collateral ligaments by stressing
each side, with the knee slightly flexed.
(v) Assess the cruciate ligaments
(a) with the knee flexed, attempt to move the tibia backwards
(posterior cruciate tear) or abnormally forwards (anterior
cruciate tear)
(b) a posterior cruciate tear allows the head of the tibia to slip
backwards on posterior stressing, which then moves forwards
into a correct anatomical position on anterior stressing
(c) this forwards movement does not equate to an anterior
cruciate tear, which is only indicated by an abnormally
forwards position.

4 X-ray all patients and look for an associated fracture, such as:
(i) Tibial condyle fracture.
(ii) Avulsion fracture of the tibial spine in cruciate ligament tears.
(iii) Flake fracture of the lateral or medial femoral condyle in
collateral ligament tears.
(iv) Vertical avulsion fracture off the lateral tibia from the lateral
capsular ligament attachment (Segond’s fracture).
(v) Avulsion of the tibial tubercle (Osgood–Schlatter’s disease) due
to traction apophysitis, more common in young male teenagers.

Warning: passive and active movements of the knee are restricted by the

pain and swelling in the setting of acute injury and are difficult to evaluate

accurately. Reassessment after a few days is essential.

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