Abstract
Hinges were used early in total knee replacement history. The stems were too short, the trochlear groove was absent or inadequate and the mechanism lacked strength. Hinges, therefore, acquired a very bad reputation.
As the only stems in early knees were on hinges, I used them when necessary, i.e. a completely missing medial collateral ligament, a flexion gap of more than three centimeters with a normal extension gap and missing bone. I used a Guepar II and my results were good up to 20 years when the plastic wore out and the spindle was damaged. By that time, new spindles were not available and the cases had to be revised. Revision of a cemented bowed stem is a nightmare. One would wish, therefore, to have a design, where the bearings could be detached from the stems and a new bearing inserted.
The main problem with hinges nowadays is that they all rotate, or at any rate, all the hinges which I can get, rotate.
The commonest indication for a hinge is the multiply revised knee due to missed tibial torsion. A rotating hinge used in a situation like this results in the patient externally rotating the tibia and subluxating or dislocating the patella. They, therefore, cannot use this knee as the leading leg on any activity and they may have instability or falls as a result of the patellar dislocation.
It is not difficult to block rotation but, so far as I know, no one has done it.
Is there a role for hinge? Very seldom and not with the existing designs.
