10 Femur
10.1 Anterior Approach
R. Bauer, F. Kerschbaumer, S. Poisel
10.1.1 Principal Indications
Tumors
Extensor release procedures for a knee flexion deficit
Quadriceps necrosis
10.1.2 Positioning and Incision
The patient is placed in the supine position, with the leg draped so as to allow free movement. The incision is straight, following an imaginary line running from the anterior superior iliac spine to the lateral border of the patella. The length of the skin incision depends on individual requirements ( Fig. 10.1 ). After the subcutaneous tissue and fascia have been split, the layer between the rectus femoris and vastus lateralis is dissected. The dissection should be made from distal to proximal to avoid injury to the more proximally coursing vessels and nerves ( Fig. 10.2 ).
10.1.3 Exposure of the Femoral Shaft
Following mobilization of the rectus femoris, this is retracted medially with wound retractors. In the distal region of the wound, the rectus femoris tendon is detached sharply with a scalpel from the vastus lateralis and the subjacent vastus intermedius.
Now the branches of the lateral circumflex femoral artery and vein and the branches of the femoral nerve supplying the vastus lateralis in the middle and upper wound regions are identified and raised ( Fig. 10.3 ). More distally, some transversely running vessels need to be transected.
Exposure of the neurovascular bundles, particularly the proximal one, requires transection of the thick fascia covering vastus intermedius. A straight incision is now made in vastus intermedius, extending to the bone. This incision may be made with a diathermy scalpel to minimize bleeding. After medial and lateral retraction of the muscle, Hohmann elevators may be inserted ( Fig. 10.4 ). If opening of the knee joint is not intended, vastus intermedius should be incised to at most a handbreadth proximal to the superior border of the patella so that injury to the superior recess of the knee joint capsule (suprapatellar bursa) may be avoided.
10.1.4 Extension of the Approach
The anterior approach to the femur can be extended proximally by lengthening the incision along the iliac crest, as in the anterior, iliofemoral approach to the hip joint. Distal extension of the approach, corresponding to the lateral parapatellar approach to the knee joint, is likewise possible.
10.1.5 Wound Closure
Wound closure is effected by suturing vastus intermedius with interrupted sutures and loose suture of the femoral fascia.
10.1.6 Note
The anterior approach to the femur is employed only in exceptional cases. After using this approach, flexion deficits of the knee joint, probably attributable to iatrogenic damage to the gliding mechanism of the quadriceps, have been observed.
10.2 Lateral Proximal Approach to the Medullary Cavity of the Femur
K. Weise, D. Höntzsch
10.2.1 Principal Indications
Medullary nailing of the femur
Fractures
Pseudarthrosis
Bone marrow aspiration with a reamer–irrigator–aspirator
10.2.2 Positioning and Incision
Different positions may be used:
Supine
Lateral decubitus
Supine on an extension table
Lateral decubitus on an extension table
The approach is identical in each case.
It must be ensured that the table is radiolucent as far as the hip. The incision is an extension of the slightly curved long axis of the femur 3–5 cm cranial to the tip of the trochanter ( Fig. 10.5 ).
10.2.3 Exposure of the Proximal Femoral Entry Site
The superficial gluteal fascia is split, followed by the muscle fascia of gluteus medius ( Fig. 10.6 ).
The fibers of gluteus medius are divided bluntly and sharply in the line of the fibers. The greater trochanter is palpated deep in the distally directed approach funnel. The desired entry site is found (lateral to the trochanter tip, on the trochanter tip, or in the trochanteric fossa).
After establishing the entry site, the guidewire or opening instrument for nailing is applied and advanced longitudinally in the central axis of the femur ( Fig. 10.7 ), here shown with a guidewire.
10.2.4 Wound Closure
The wound is closed in layers.
10.3 Lateral Approach to the Femur
R. Bauer, F. Kerschbaumer, S. Poisel
10.3a Lateral Approach—General Points
10.3a.1 Principal Indications
Osteotomy
Pseudarthrosis
Lengthening of the femur
Fractures
10.3a.2 Positioning and Incision
The patient is placed in the supine position with a pad under the buttocks. The skin incision follows an imaginary line from the greater trochanter to the lateral epicondyle of the femur ( Fig. 10.8 ). The length of the incision depends on requirements. After transection of the skin and subcutaneous tissue, the fascia lata is split in line with the skin incision.
10.3a.3 Note
The lateral approach is considered to be the standard approach to the femur. This approach generally presents no technical problems and spares the innervation of vastus lateralis. In a broad lateral exposure of the femoral shaft, detachment of the periosteum in the area of the linea aspera should be avoided if possible. A drawback of this approach is transection of the perforating arteries, which adversely affects the blood supply in the region of vastus lateralis.
10.3b Lateral Approach—Exposure of the Proximal Femur
For exposure of the proximal portion of the femur, the posterior portion of the fascia lata is first of all detached as far posteriorly as possible from the vastus lateralis.
An L-shaped incision extending to the bone is then made in the vastus lateralis with the diathermy scalpel ( Fig. 10.9 ). If an intertrocanteric exposure is desired, proximal retraction of the gluteal muscles with a Langenbeck retractor is advisable. This also allows detachment of the vastus intermedius fibers as far as the neck of the femur. The muscle can now be retracted anteriorly from the lateral femoral intermuscular septum with a raspatory ( Fig. 10.10 ). Next Hohmann elevators are inserted for medial retraction of the muscle. In the distal wound area, the first perforating vessels have to be found and ligated ( Fig. 10.11 ). For exposure of the intertrochanteric region and distal portions of the hip joint capsule, the gluteal muscles are proximally retracted with a Langenbeck retractor, after which the remaining parts of the vastus intermedius are split. Using the raspatory, the femoral neck can now be exposed from the medial side, and a Hohmann elevator may be inserted at this site ( Fig. 10.12 ).
10.3b.1 Anatomical Site
The cross-sectional diagram ( Fig. 10.13 ) shows that the vastus lateralis projects posteriorly beyond the femoral shaft. Careful detachment of the vastus lateralis from the lateral femoral intermuscular septum as far as the linea aspera is therefore required.
Dissection behind the lateral femoral intermuscular septum may cause injury to the perforating vessels.
10.3b.2 Wound Closure
The vastus lateralis is reattached both proximally and laterally. The wound is further closed by suture of the fascia lata.
10.3b.3 Dangers
Inadvertent transection of a perforating vessel may lead to mediad retraction of the end of the artery. If this happens, detachment of the periosteum at the linea aspera should be attempted so that the bleeding vessel may be grasped and ligated. If exposure in this manner is not feasible, it may be necessary to identify the deep femoral artery and to ligate it as far distally as possible.
10.3c Lateral Approach—Exposure of the Distal Femur
If exposure of the distal femoral shaft is necessary, the skin incision is extended to a point just proximal to Gerdy′stubercle. The iliotibial band is split along a line paralleling the skin incision ( Fig. 10.14 ). If exposure of the lateral femoral condyle is required, the lateral superior genicular artery and vein have to be ligated and transected ( Fig. 10.15 ). Subsequently, the index finger is inserted between vastus lateralis and the femoral periosteum from the distal side, and the muscle is cautiously lifted up. Further dissection of the muscle is carried out in a proximal direction with a raspatory. Perforating vessels need to be ligated and transected ( Fig. 10.16 ). Vastus lateralis, thus mobilized, is retracted medially with Hohmann elevators. If necessary, a Hohmann elevator may also be inserted posteriorly. Any subperiosteal exposure of the posterior aspect of the femur or at the linea aspera has to be done very sparingly in order not to compromise the blood supply of the bone ( Fig. 10.17 ). The two nutrient arteries that supply the femoral shaft at the boundary between the proximal and the middle thirds and between the middle and distal thirds must be spared.
If possible, the synovial knee joint capsule should not be opened. Properly cautious dissection allows the infrapatellar synovial fold to be recognized both laterally and in the area of the superior recess, and to be lifted off the underlying bone.
10.3c.1 Anatomical Site
The diagrammatic cross-section through the distal third of the femur shows that, in this area, the muscle mass of vastus lateralis is distinctly smaller than it is proximally, and that it barely extends posteriorly beyond the femur ( Fig. 10.18 ).
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