Page 106 - ASOP ROT Study Guide

The cruciate ligaments are not capable of spontaneous healing because if torn, the blood supply is lost. In rare
circumstances the cruciate ligament may be pulled off with a fragment of bone at one end. If the fragment and
associated ligament are put back within a few hours then the whole ligament may survive with its blood
supply relatively undamaged.

8 . 4 . 2 Clinical presentation
In an acute injury the knee swells quickly, indicating a hemarthrosis brought on by active bleeding from the artery
in the cruciate ligament. Sometimes the patient reports feeling a "pop" which is the ligament tearing. The
swelling eventually resolves and it is only after a few weeks that the chronic problems that are described
below arise.
Loss of a cruciate leads to loss of antero-posterior stability, particularly in flexion, and loss of rotatory stability
when twisting and turning. This injury, therefore, is particularly disabling for sportsmen and women. Some
patients, however, have no symptoms and there is no explanation for this at the moment. Many patients only
experience symptoms when descending stairs or when twisting or turning.
Rotatory instability and pivot shift which follow some cruciate ligament injuries are described in Unit 2a of the
Skeletal Anatomy & Physiology module.

8 . 4 . 3 Management
In general the ligament should be left untreated for a while and the knee muscles rehabilitated. Treatment
should be offered only if symptoms interfere with daily life or if the patient wishes to return to sport. Treatment
consists of replacing the torn ligament with a synthetic one. These replacement ligaments are new and they
have an unknown life span. If patients persist in vigorous activity the prosthetic ligament is more likely to fail
because, unlike a natural ligament, it has no sensory receptors in it to let the brain know if the ligament is being
overstretched. The brain is therefore unable to initiate muscle action to protect the joint.

8 . 5 Dislocation of the Patella
8 . 5 . 1 Etiology
This condition is usually associated with a malformation of either the patella or the lateral femoral condyle. This
leads to the patella moving abrasively on the femur (mal-tracking) which is painful because of the associated
muscle spasm.

http://kneeandshoulderclinic.com.au/knees/surgical-conditions/patella-instability/