Surgical Technique; Establish Femoral Alignment - Zimmer MIS Multi-Reference Surgical Technique

10
Zimmer MIS Multi-Reference 4-in-1 Femoral Instrumentation Surgical Technique
Step One
Establish Femoral
Alignment
Use the 8mm IM Drill w/Step to drill a
hole in the center of the patellar sulcus
of the distal femur (Fig. 1a), making
sure that the drill is parallel to the
shaft of the femur in both the
anteroposterior and lateral projections.
The hole should be approximately
one-half to one centimeter anterior
to the origin of the posterior
cruciate ligament. Medial or lateral
displacement of the hole may be
needed according to preoperative
templating of the A/P radiograph.
Fig. 1a
The step on the drill will enlarge the
entrance hole on the femur to 12mm.
This will reduce intramedullary pressure
during placement of subsequent IM
guides. Suction the canal to remove
medullary contents.
The Mini Adjustable IM Alignment
Guide is available with two
intramedullary rod lengths. The rod
on the standard instrument is 229mm
(9 inches) long and the rod on the
short instrument is 165mm (6.5
inches). Choose the length best suited
to the length of the patient's leg,
which will provide the most accurate
reproduction of the anatomic axis. If
the femoral anatomy has been altered,
as in a femur with a long-stemmed hip
prosthesis or with a femoral fracture
malunion, use the Adjustable IM
Alignment Guide, Short and use the
optional extramedullary alignment
technique.
NOTE: The Mini Adjustable IM
Alignment Guide, Short (Fig. 1b)
is a shortened version of the Mini
Adjustable IM Alignment Guide, Long.
When the Mini Standard Cut Plate is
attached to the Mini Adjustable IM
Alignment Guide, Short, the same
amount of bone is removed as when it
is attached to the Mini Adjustable IM
Alignment Guide, Long. This is different
than the original Multi-Reference 4-in-
1, Micro IM Alignment Guide 165mm
(6.5 inch) which was intended for
use with Micro implants. When the
Standard Cut Plate was attached, the
Micro IM Alignment Guide removed
one millimeter less distal bone than
the standard Adjustable IM Alignment
Guide with the Standard Cut Plate
attached. The new Mini IM Alignment
Guides accommodate the resection for
the Micro implants with the Mini Micro
Cut Plate.
Fig. 1b
NOTE: It is preferable to use the longest
intramedullary rod to help ensure
the most accurate replication of the
anatomic axis.
Set the Mini Adjustable IM Alignment
Guide to the proper valgus angle
as determined by preoperative
radiographs. Check to ensure that the
proper "Right" or "Left" indication
(Fig. 1c) is used and engage the lock
mechanism (Fig. 1d).
Fig. 1c
Fig. 1d