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Isometric quadriceps exercises are continued.
Full weight bearing, with the support of one or
two crutches, as necessary, is allowed). In our
follow up of 22 patients at average 29 months
(8-65) the difference in the side to side upper
leg circumference, 15cm above the knee, was
only 0.19cm (0-1.5cm) [9].
Should loss of motion persist for longer than 9
months, after an MPFL reconstruction, we
would recommend a percutaneus sequential
fish scale typeof tenotomy, neartheimplantation
of the ligament on the patella, till full range of
motion is restored [31].
Fractures
In our series we only had had three
redislocations, all associated with fractures of
the medial rim of the patella [30]. In all these
patients the fracture occurred with a definitive
injury; in two this happened in contact sport,
one in soccer and the other in rugby football.
The third patient sustained a redislocation
when she fell off a chair trying to replace a
fused light bulb. The fractures occurred
respectively 2, 5 and 10 years after the initial
surgery. In our reconstructing technique two 3
-3.5mm drill holes, 10mm apart, are made on
the medial edge of the patella exiting the
anterior cortex approximately 10mm from the
medial edge. These fractures were similar to
that seen in acute primary patelladislocations
[32]. A gracilis outograft was used for
reconstructing the ligament.
This reconstructed ligament is stronger than
the original MPFL and as the underlying
predisposing factors have not been addressed
there will, at times, be high strain on the
ligament. This can result in a patella fracture
through the drill holes which acts as stress
raisers. In all three cases the fracture involved
not more than the 1cm of the medial patella
(fig. 4).
The fractures were reduced and fixed with
screws all resulting in a stable patella with no
longstanding sequel from the fractures.
Mikashima [17] reported two fractures in
12 knees. A single transverse drill hole, of
4.5mm was done from medial to lateral through
the patella.
These fractures all occurred within 6 weeks
from the surgery resulting in a nearly 16%
incidence of fractures. Both Christiansen [5]
using two 4.5mm and Gomes using a single
7mm [14] transverse drill holes, reported non
traumatic patella fractures. It is possible that
too large drill holes increase the possibility of a
fracture especially when they transverse the
patella. Fractures of the medial rim of the
patella usually do not involve the articular
surface of the patella and is relatively easy to
treat in contrast transverse fractures which
always involve the articular surface of the
patella and in most cases there is a disruption of
the cortex which makes it more serious and an
anatomical reduction difficult (fig. 5).
Fig. 4 : Redislocation after MPFL reconstruction
with a fracture of the medial rim reattached with a
screw and washer.