Case Vignette

Knee Ligament Injuries

The knee joint is a most complex structure.  It is capable of hinging, gliding and rotation.  Attempts to reproduce this complex biomechanical event have been met with limited success.  Nature’s competence includes a special arrangement of ligaments both within and without the joint.


The ligaments on the inside include the anterior and posterior cruciates.  The anterior cruciate ligament is not uncommonly torn during rigorous sporting activities.    Footballers, netballers and snow skiers are all vulnerable.

So What?

The cruciate ligament itself has a rich blood supply.  When the ligament is ruptured, the knee joint rapidly fills with blood.  It is associated with considerable pain.


Over the subsequent weeks, the so-called haemarthrosis resolves and the patient gradually improves.  Unfortunately, some patients note ongoing rotary instability.  They can walk and even run in a straight line but attempting to pivot or suddenly change direction is met with pain and a sensation of instability.  The knee joint sometimes gives way.


Many of these patients require an operative reconstruction.  The hamstring tendons can be harvested from the thigh or the patellar tendon can be harvested from the front of the knee itself.  Artificial ligaments are sometimes used, although with limited success.


A patient who has an ongoing cruciate ligament instability that has not been repaired, and who remains seriously symptomatic, will exhibit a loss of up to 10% of whole person function.  You can quantify this loss using Table 17-33 on page 546 of the AMA 5 Guides.


Even after a successful reconstruction, some patients will continue to exhibit mild ongoing instability.  Most patients will thereby exhibit a loss of 3% of whole person function.  General damages may therefore be awarded as a result.  In addition, as a result of the ongoing instability, remunerative, recreational and domestic activities could be compromised.  Further financial losses may accrue.

But Wait, There’s More

The chronic instability that ensues may be a precursor to osteoarthritis.  Over decades, the disease may progress and a joint replacement is eventually required.  Very considerable costs can result.  Your orthopaedic expert will assist you in quantifying the true extent of the loss.