Partial Epiphyseal Preservation of the Distal Part of the Femur
Patients are managed with chemotherapy and, after the induction period,
definitive surgical treatment of the primary lesion is performed. Magnetic
resonance images are acquired with a 1.5-T Magnetom Vision unit (Siemens,
Erlangen, Germany) at the time of the diagnosis and after chemotherapy in
order to evaluate the tumor response (Fig.
1). All operations are performed in a clean-air enclosure with
vertical airflow and usually with spinal anesthesia. The patient is placed on
the operating table in the supine position. A sandbag is placed under the
ipsilateral buttock. A long midline incision is made, beginning in the middle
part of the thigh, and a medial parapatellar arthrotomy is performed to enable
a wide exposure of the distal part of the femur and the knee joint. The biopsy
track is left in continuity with the specimen. The distal part of the femur is
approached through the interval between the rectus femoris and the vastus
medialis. If there is an extraosseous tumor component, a cuff of normal muscle
must be excised. Proximal femoral osteotomy is performed at the appropriate
location as determined on the basis of the preoperative imaging studies. All
remaining soft tissues at the level of the transection are cleared. After the
posterior and medial structures have been protected and retracted
(Fig. 2), the osteotomy is
performed perpendicular to the long axis of the femur.
Following the osteotomy, the distal part of the femur is pulled forward in
order to expose the soft-tissue attachments of the popliteal space
(Fig. 3). The popliteal artery
is mobilized, and the geniculate vessels are ligated and transected. Both
heads of the gastrocnemius are released, and the posterior capsule is opened.
The cruciate and collateral ligaments are identified and are left intact and
attached to the epiphysis that is saved. The next step is to mark the
intraepiphyseal site (Fig. 4).
The osteotomy is planned 1 to 2 cm from the distal edge of tumor growth,
defined as the point at which the marrow signal intensity changes from
abnormal to normal. At the time of surgery, measurements on preoperative
magnetic resonance imaging are correlated with anatomical landmarks (the
epicondyles, the intercondylar notch roof, and the extent of the femoral
articular cartilage). Following the osteotomy, the distal part of the femur is
passed off the operative field. of both condyles and into the allograft. Then,
the osteotomy site is stabilized by means of internal fixation with cancellous
screws compressing the metaphyseal bone
(Fig. 6). Before the proximal
osteotomy site is stabilized, the posterior capsule is repaired by suturing
autologous capsular tissues to the capsular tissues provided by the allograft.
A condylar buttress plate is placed to fix the diaphyseal osteotomy site. In
order to minimize the risk of fracture, the plate should cover the entire
length of the allograft (Fig.
7).
CRITICAL CONCEPTSINDICATIONS:Tumors with no evidence of progression clinically or on magnetic resonance
imaging studies during chemotherapyA residual epiphysis of at least 1 cm in thickness should be available in
order to allow for the fixation of the osteotomy junction and the achievement
of safe oncologic marginsCONTRAINDICATIONS:Tumor progression during chemotherapyPatients in whom preoperative imaging studies demonstrate evidence of
epiphyseal compromiseVery young patients (patients less than eight years old) who are predicted
to have a substantial final limb-length discrepancyPITFALLS:It is important to have stringent preoperative criteria for selecting
patients who are suitable for this techniqueThe procedure is best performed by an orthopaedic oncologic surgeon with
experience in knee reconstructive surgery and sports-medicine surgeryAll previous biopsy sites and all potentially contaminated tissues,
including any needle biopsy tracks, should be removed en blocThe major neurovascular bundle must be free of tumorIntraoperative guidelines or parameters for epiphyseal osteotomies are
based on measurements made on preoperative magnetic resonance imaging
studiesIn order to avoid allograft fracture, the internal fixation device should
cover the entire length of the graftIn tibial reconstructions, it is important to stabilize the proximal
tibiofibular joint and to use a medial gastrocnemius rotation flap to cover
the allograftAUTHOR UPDATE:Since the original article was published, the surgical approach has
remained basically unchanged. However, in order to achieve the closest
possible anatomical match, the selection of the allograft is now performed on
the basis of a comparison of the allograft computerized tomographic scans that
are available at our bone bank with those of the patient and not on the basis
of radiographs, as was done previously. In the original article, the
diaphyseal osteotomy sites in some patients were fixed with intramedullary
rods; currently, these devices are not used because they were associated with
a higher nonunion rate. Plate fixation is now used for the majority of our
patients because we believe that it imparts greater mechanical stability to
the reconstruction. The postoperative care and rehabilitation have remained
unchanged. At the present time, twenty-three patients with high-grade
osteosarcoma around the knee have been managed with this technique involving
partial epiphyseal preservation, with no instances of recurrence in the
retained epiphysis.After the tumor has been resected, an allograft segment that has been
tailored to fit the bone defect is inserted. Fresh-frozen allografts are
obtained and stored according to a technique that has been described
previously4. The
allograft is selected on the basis of a comparison of the radiographs of the
patient with those of the donor. After the donor bone is thawed in a warm
solution, it is cut to the proper length
(Fig. 5). The intraepiphyseal
osteotomy site is temporarily secured with threaded Kirschner wires that are
inserted through the distal parts
CRITICAL CONCEPTS
INDICATIONS:
Tumors with no evidence of progression clinically or on magnetic resonance
imaging studies during chemotherapyA residual epiphysis of at least 1 cm in thickness should be available in
order to allow for the fixation of the osteotomy junction and the achievement
of safe oncologic margins
Tumors with no evidence of progression clinically or on magnetic resonance
imaging studies during chemotherapy
A residual epiphysis of at least 1 cm in thickness should be available in
order to allow for the fixation of the osteotomy junction and the achievement
of safe oncologic margins
CONTRAINDICATIONS:
Tumor progression during chemotherapyPatients in whom preoperative imaging studies demonstrate evidence of
epiphyseal compromiseVery young patients (patients less than eight years old) who are predicted
to have a substantial final limb-length discrepancy
Tumor progression during chemotherapy
Patients in whom preoperative imaging studies demonstrate evidence of
epiphyseal compromise
Very young patients (patients less than eight years old) who are predicted
to have a substantial final limb-length discrepancy
PITFALLS:
It is important to have stringent preoperative criteria for selecting
patients who are suitable for this techniqueThe procedure is best performed by an orthopaedic oncologic surgeon with
experience in knee reconstructive surgery and sports-medicine surgeryAll previous biopsy sites and all potentially contaminated tissues,
including any needle biopsy tracks, should be removed en blocThe major neurovascular bundle must be free of tumorIntraoperative guidelines or parameters for epiphyseal osteotomies are
based on measurements made on preoperative magnetic resonance imaging
studiesIn order to avoid allograft fracture, the internal fixation device should
cover the entire length of the graftIn tibial reconstructions, it is important to stabilize the proximal
tibiofibular joint and to use a medial gastrocnemius rotation flap to cover
the allograft
It is important to have stringent preoperative criteria for selecting
patients who are suitable for this technique
The procedure is best performed by an orthopaedic oncologic surgeon with
experience in knee reconstructive surgery and sports-medicine surgery
All previous biopsy sites and all potentially contaminated tissues,
including any needle biopsy tracks, should be removed en bloc
The major neurovascular bundle must be free of tumor
Intraoperative guidelines or parameters for epiphyseal osteotomies are
based on measurements made on preoperative magnetic resonance imaging
studies
In order to avoid allograft fracture, the internal fixation device should
cover the entire length of the graft
In tibial reconstructions, it is important to stabilize the proximal
tibiofibular joint and to use a medial gastrocnemius rotation flap to cover
the allograft
AUTHOR UPDATE:
Since the original article was published, the surgical approach has
remained basically unchanged. However, in order to achieve the closest
possible anatomical match, the selection of the allograft is now performed on
the basis of a comparison of the allograft computerized tomographic scans that
are available at our bone bank with those of the patient and not on the basis
of radiographs, as was done previously. In the original article, the
diaphyseal osteotomy sites in some patients were fixed with intramedullary
rods; currently, these devices are not used because they were associated with
a higher nonunion rate. Plate fixation is now used for the majority of our
patients because we believe that it imparts greater mechanical stability to
the reconstruction. The postoperative care and rehabilitation have remained
unchanged. At the present time, twenty-three patients with high-grade
osteosarcoma around the knee have been managed with this technique involving
partial epiphyseal preservation, with no instances of recurrence in the
retained epiphysis.
After the tumor has been resected, an allograft segment that has been
tailored to fit the bone defect is inserted. Fresh-frozen allografts are
obtained and stored according to a technique that has been described
previously4. The
allograft is selected on the basis of a comparison of the radiographs of the
patient with those of the donor. After the donor bone is thawed in a warm
solution, it is cut to the proper length
(Fig. 5). The intraepiphyseal
osteotomy site is temporarily secured with threaded Kirschner wires that are
inserted through the distal parts
Two suction drains are inserted and, after lavage of the wound with saline
solution, a meticulous suture repair of the quadriceps is required. A layered
closure of the subcutaneous tissues and skin is then performed. Antibiotics
are given intravenously according to the usual prophylactic protocol, and
routine anticoagulation therapy is not used. External splinting with a brace
with the knee in full extension is used until the wound has healed.
After two days, the drains are removed and the wound is inspected. Passive
range-of-motion exercises are begun at two weeks after the operation. The
patient is allowed partial weight-bearing at eight to twelve weeks
(Fig. 8).
Partial Epiphyseal Preservation of the Proximal Part of the
Tibia
The same basic principles are applied when an intraepiphyseal resection of
the proximal part of the tibia is performed
(Fig. 9). A long midline
incision is made, beginning at the proximal part of the patella and extending
over the tibia. A medial parapatellar arthrotomy is performed to enable a wide
exposure of the proximal part of the tibia and the knee joint. The biopsy
track is left in continuity with the specimen. The proximal part of the tibia
is exposed extraperiosteally and, if there is an extraosseous tumor component,
a cuff of normal muscle must be excised. The proximal tibiofibular joint is
opened completely. A distal tibial osteotomy is planned at the appropriate
location as determined on the basis of the preoperative imaging studies. All
remaining soft tissues at the level of the transection are cleared. After the
posterior and lateral structures have been protected and retracted, the
osteotomy is performed perpendicular to the long axis of the tibia.
Following the osteotomy, the proximal part of the tibia is pulled forward
in order to expose the soft-tissue attachments of the popliteal space
(Fig. 10). Both menisci, the
medial collateral ligament, and both cruciate ligaments are identified and are
left intact around the epiphysis that is saved. The next step is to mark the
intraepiphyseal osteotomy site. The osteotomy is planned 1 to 2 cm from the
proximal edge of tumor growth, defined as the point at which the marrow signal
intensity changes from abnormal to normal
(Fig. 11). At the time of
surgery, measurements on preoperative magnetic resonance images are correlated
with anatomical landmarks (the tibial plateau surface, the proximal end of the
fibula, and the patellar tendon insertion on the tibia). Following the
osteotomy, the proximal part of the tibia is passed off the operative
field.
After the tumor has been resected (Fig.
12), an allograft segment that has been tailored to fit the bone
defect is inserted. After the donor bone is thawed in a warm solution, it is
cut to the proper length. The intraepiphyseal osteotomy site is temporarily
secured with threaded Kirschner wires that are inserted through the proximal
part of the tibial plateau and into the allograft. Then, the osteotomy site is
stabilized by means of internal fixation with cancellous screws compressing
the metaphyseal bone. The proximal part of the fibula at the tibiofibular
joint is fixed to the proximal part of the tibia with a cancellous screw. A
plate is applied to fix the diaphyseal osteotomy site. In order to minimize
the risk of fracture, the plate should cover the entire length of the
allograft (Fig. 13).
The extensor mechanism is then reconstructed by attachment of the allograft
patellar tendon to the corresponding host patellar tendon
(Fig. 14). The donor patellar
tendon is transected 2 cm from its insertion on the patella and is sectioned
longitudinally. The two flaps created by the longitudinal sectioning of the
donor tendon are applied over the host patellar tendon and are sutured to it
to restore the extensor mechanism. Finally, a medial gastrocnemius
transposition flap is created to provide soft-tissue coverage of the proximal
tibial allograft.
Two suction drains are inserted, and, after lavage of the wound with saline
solution, layered closure of the subcutaneous tissues and skin is performed.
Antibiotics are given intravenously according to the usual prophylactic
protocol, and routine anticoagulation therapy is not used. External splinting
with a brace with the knee in full extension is used until the wound has
healed.
After two days, the drains are removed and the wound is inspected. Passive
range-of-motion exercises are begun at two weeks after the operation. The
patient is allowed partial weight-bearing at eight to twelve weeks
(Fig. 15).