- Discussion:
- Operative Technique:
-
position:
- supine with several folded sheets placed underneath the injured thigh and knee;
- the injuried thigh must be flexed and elevated higher than the uninjured thigh inorder to obtain a good lateral view;
-
incision:
- anterior longitudinal incision from inferior patella to the tibial tubercle;
- patellar paratenon is dissected out as a distinct layer;
- patella tendon is incised longitudinally and is retracted w/ Gelpi retractors;
- ligamentum mucosum is released to allow fat pad to drop inferiorly;
- palpate the PCL tendon;
-
percutaneous insertion stratedgy:
- requirements: an adequate closed reduction should be possible (or otherwise an open reduction strategy will be required);
- reduction:
- first reduce fracture w/ traction, w/ guide pins or K wires, w/ care to avoid screw
placement that would interfere w/ central nail placement;
- alternatively, a large tenaculum clamp can be applied percutaneously to hold the reduction;
- remember that reduction is often achieved with full extension, and temporary pin fixation is required so that the reduction is not lost
when the knee is flexed in preparation for nail insertion;
-
incision:
- make a 5 cm incision over the midline of the patellar tendon, and split the patella tendon and the underlying fat
pad longitudinally in line with the incision;
- entry point is 3-4 mm anterior to the PCL insertion using a sharp awl;
- ensure that the guide wire is centralized on two flourscopic views w/ respect to the distal fragment (and not the proximal shaft);
- once distal fragment has been properly reamed, the distal fragment can be reamed if necessary;
- if reaming has remained central in both fragments, reduction should occur as the the nail is driven across the fracture;
-
open reduction stratedgy:
- if fracture reduction cannot be achieved, then an open reduction is required, using a anterior
midline incision (similar to a TKR incision);
-
entry point:
- depends in part on the curvature of the nail;
- nails w/ a large distal bend will generally be inserted closer to the PCL insertion, where as
nails w/ a smaller bow will be inserted slightly more anteriorly;
- in general, if the starting hole is too anterior, the fracture site will fall into flexion (and the knee will lose extension);
- if the nail is inserted too posteriorly, then the frx will fall into extension (and the knee will lose flexion;
-
reaming technique:
- with retrograde reaming, it is important to keep a "rolled bump" under the thigh inorder to keep the hip and knee flexed;
- by keeping the hip and knee flexed muscle forces across the thigh are relaxed which facilitates reduction and reamer passage;
- if the hip and knee remain extended, there will be displacement of the fracture site in the lateral plane, which
may cause eccentric reaming and subsequent fracture malalignment;
-
nail passage:
- use of a longer length nail will help centralized the nail in the isthmus (and facilitates reduction);
- note that with distal femoral fractures, the nail must be inserted in a central position, and the fracture must be reduced
prior to nail passage across the frx site (a malreduction will not magically be corrected after the nail is fully seated);
-
proximal interlocking:
- generally the proximal interlocking screws need to be inserted in the AP plane using a free hand technique;
- sizing the screw may be difficult but one can estimate the proper screw length by noting the relative size of the nail in the femoral canal;
- if a 10 mm nail takes up about 1/3 of the shaft diameter (on the lateral view) then the proper screw length would be about 30 to 32 mm;
- apply an absorbable suture to the screw neck so that the screw is not lost in the soft tissues;
- note that the
femoral artery is located medial to the femur throughout its course;
- all branches of the femoral artery cross at a point 4 cm distal to the lesser trochanter;
- hence, keeping the drill bit above the level of the lesser trochanter and avoiding medial aspect of the bone will help prevent vascular injury;
- similarly, placement of interlocking screws above level of lesser trochanter reduces the risk of injury to branches of the femoral nerve;
- note that the deep branch of the
medial femoral circumflex artery invariably crosses the femur posteriorly at least 10 mm, and usually 16 to 20 mm,
proximal to the superior aspect of the lesser trochanter;
- references:
- Neurologic and vascular structures at risk during anterior-posterior locking of retrograde femoral nails.
J. Riina et al. J. Orthop Trauma. Vol 12. No 6. 1998. p 379-381.
-
Anatomy of the medial femoral circumflex artery and its surgical implications.
- Complications:
- secondary femoral fracture:
- has been documented in numerous case reports, and apparently occurs as a result of the stress riser created by an IM nail which ends in the diaphysis;
- ref: Femoral fracture at the proximal end of an intramedullary supracondylar nail: a case report.
ED Leibner MD et al. American Journal of Orthopedics. Jan 1999. p 53.
- 24 yr old male who was initially treated w/ Seligson Nail for extra-articular supra-condylar fracture. Apparrently, an attempt was made to insert
a second proximal locking screw (an empty drill hole is seen in the femur);
The fracture occurred 8 months later, at the level of this stress riser;
- the previously mentioned supra-condylar fracture which occurred 8 months following insertion of a Seligson Nail,
was treated successively with a retrograde
Synthes Femoral Nail;
Intramedullary supracondylar nailing of femoral fractures. A preliminary report of the GSH supracondylar nail.
Interlocking intramedullary nailing for supracondylar and intercondylar fractures of the distal part of the femur.
Effects of retrograde femoral intramedullary nailing on the patellofemoral articulation.
E. Morgan et al. Journal of Orthopaedic Trauma. Vol 13. No 1. 1999. p 13.
