The new dorsal osteosynthesis (reconstruction) approach was developed to reduce the
risks of plate exposure, infection, and early removal in difficult cases such as Gustilo–Anderson
type IIIB or C open tibial fractures and Cierny–Mader type III and IV chronic osteomyelitis.
The advantages of this method are that the reconstruction with microvascular or pedicle
fibula flaps and plating can be done through healthy noncompromised posterior compartment—no
separate incision for osteosynthesis or flap insertion is needed.
Material
Retrospective cohort study was performed to evaluate the functional outcome, union
rate, and complications after tibia reconstruction. Eleven patients underwent dorsal
osteosynthesis for tibia defect reconstruction with free or pedicle fibula flaps in
the Microsurgery Centre of Latvia between 2010 and 2015. All patients had a history
of open tibia fractures. Patients were divided in three groups. In the first group,
three patients developed late complications after previously done bone and soft tissue
reconstructions. The second group included six patients with chronic osteomyelitis
after osteosynthesis with a plate, using classical anteromedial or anterolateral approaches
without any reconstruction. The third group included two patients with Gustilo–Anderson
type IIIB and IIIC tibia fractures treated with monolateral and Ilizarov apparatus,
also without any reconstruction. Group characteristic are shown in [Table 1].
Table 1
Group characteristics
|
Age
|
Gender
|
Problem
|
Bone defect
|
Reconstruction
|
|
First group
|
|
1.
|
26
|
M
|
Nonunion
|
Tibial shaft, 2 cm
|
Distal pedicle, 7.9 cm
|
|
2.
|
43
|
M
|
Nonunion
|
Tibial shaft, 14 cm
|
Proximal pedicle, 20.2 cm
|
|
3.
|
45
|
M
|
Osteomyelitis 3A
|
Tibial shaft, 14 cm
|
Contralateral single barrel, 18 cm
|
|
Second group
|
|
4.
|
54
|
M
|
Osteomyelitis 4A
|
Distal tibia, 13 cm
|
Contralateral single barrel, 19cm
|
|
5.
|
54
|
F
|
Osteomyelitis 3A
|
Distal tibia, 3.5 cm
|
Distal pedicle, 8.5 cm
|
|
6.
|
57
|
M
|
Osteomyelitis 4A
|
Distal tibia, 9.3 cm
|
Contralateral double barrel, 12/10 cm
|
|
7.
|
41
|
M
|
Osteomyelitis 3A
|
Distal tibia, 10.7 cm
|
Distal pedicle, 15,4 cm
|
|
8.
|
54
|
M
|
Osteomyelitis 4C
|
Tibial shaft, 4.6 cm
|
Proximal pedicle, 9,6 cm
|
|
9.
|
40
|
M
|
Osteomyelitis 3A
|
Distal tibia, 4.8 cm
|
Distal pedicle, 10.2 cm
|
|
Third group
|
|
10.
|
24
|
M
|
Gustilo–Anderson IIIB
|
Tibial shaft, 6.5 cm
|
Contralateral double barrel, 9.6/8 cm
|
|
11.
|
25
|
M
|
Gustilo–Anderson IIIC
|
Tibial shaft, 9.3 cm
|
Contralateral double barrel, 11.7/11.6 cm
|
Surgical Procedure
Patient is operated in the abdominal position. Posterior compartments of both legs
are on top, and feet are slightly flexed.
In cases of free flap incision going from medial side through posterior compartments,
gastrocnemius muscles are retracted laterally or medially. Soleus muscle has to be
dissected and sharply detached from tibia. Posterior tibial artery (PTA) and tibial
nerve (TN) can be observed till bifurcation. Tibialis posterior, flexor hallucis longus,
and flexor digitorum longus muscles are gently detached from medial side to avoid
damaging of motor nerve branches. After dividing last muscles, dorsal side of the
tibia can be fully observed. Posterior tibial vessels are dissected starting from
peroneal artery (PA) till medial ankle and can be used at any level for microvascular
end-to-side anastomosis. Contralateral fibula flap can be harvested from dorsal side
of the leg.
If pedicled fibula flap is used for reconstruction, skin incision can be done from
lateral side, closer to fibula, for better exposure of PA.[1]
[2]
[3] Flaps can be proximally (anterograde flow) or distally (retrograde flow) based depending
on defect localization.[4] Proximally based pedicle vascularized fibula graft can be used for tibial shaft
defects and retrograde flap is recommended for distal tibial defects. It is not necessary
to dissect PTA and TN ([Figs. 1] and [2]).
Fig. 1 The cross-section differences for the pedicle (left) and free flap (right).
Fig. 2 The differences for flap vascular pedicles (free flap on the left and pedicle flap
on the right).
After flap harvest, osteosynthesis is done through dorsal approach—plate is mounted
from dorsal side of the tibia. Some additional cortical screws can be used to fix
a single or double barrel. Some difficulties can be anticipated in inserting the upper
part of plate as bifurcation of PA and PTA lies there. Gentle distraction has to be
applied to pull away blood vessels and insert screws. The skin paddle has to be pushed
from the posterior side to the anterior side. After the dorsal side closure, the leg
is flexed in knee joint and skin paddle is fixed. Some defects can be left for secondary
healing.
We recommend leaving the external fixator on till skin heals, and remove it in outpatient
clinic after 4 to 8 weeks when circular cast can be safely applied.
Methods for Evaluation
Patient's functionality was observed by Lower Extremity Functional Scale (LEFS) score.[5] X-rays, sensation, range of motion, leg length, and Medical Research Council (MRC)
scale were evaluated.
Results
Seven patients responded for the study. Mean follow-up time for five patients was
2 years and 8 months; for two patients, it was less than 1 year. Mean LEFS score was
56.3 points (43–69) or 70.35% (53–86.2%) from maximal ability which is 100% according
to the scale. Most of the difficulties were associated with high-intensity workouts
such as running or jumping. Normal daily activities such as walking and going up or
down the stairs can be done without any difficulties. No one had abnormal sensations
at the TN innervations zone. The MRC scale score was M5 for all patients. M5 was evaluated
if patient were able to stand in the toe position against the gravity of full resistance.
Limb length differences were corrected with orthopedic foot wear ([Figs. 3] and [4]; [Table 2]).
Fig. 3 A 26-year-old patient with open tibial fracture (Gustilo–Anderson type IIIB) treated
with Ilizarov external fixator. (A, B) Infected open tibial fracture. (C, D). Follow-up 2 years after free double-barrel fibula.
Fig. 4 A 27-years-old patient with left tibial injury (Gustilo–Anderson type IIIC). Free
latissimus dorsi, fibula flaps used for early reconstruction. Nonvascularized iliac
crest bone used for reosteosynthesis. (A, B) Septic un-union. (C, D) Follow-up 1 year after distal pedicled fibula flap.
Table 2
Study outcome data
|
Patient
|
Follow-up
|
LEFS score
|
ROM knee
|
ROM ankle
|
MRC
|
Limb, cm
|
Late complications
|
|
1
|
2 y 11 mo
|
43, 53.75%
|
10-0-130
|
15-0-50
|
M5
|
82/83
|
None
|
|
2
|
3 y 1 mo
|
55, 68.75%
|
0-0-75
|
20-0-40
|
M5
|
84/85
|
None
|
|
3
|
3 y 0 mo
|
65, 81.25%
|
10-0-125
|
15-0-40
|
M5
|
89/92
|
Broken plate
|
|
4
|
2 y 9 mo
|
44, 55%
|
5-0-115
|
15-0-50
|
M5
|
105/–
|
None
|
|
5
|
8 mo
|
63, 78.75%
|
0-0-120
|
15-0-45
|
M5
|
95/96
|
None
|
|
6
|
10 mo
|
69, 86.2%
|
5-0-120
|
10-0-30
|
M5
|
100/105
|
None
|
|
7
|
8 mo
|
55, 68.75%
|
0-0-90
|
10-0-30
|
M5
|
84/85
|
None
|
Abbreviations: LEFS, Lower Extremity Functional Scale; MRC, Medical Research Council
scale; ROM, range of motion.
Discussion
Many surgical approaches are available for tibia osteosynthesis. The main approaches
for tibial reconstruction are anteromedial, anterolateral, posteromedial, and posterolateral.
Every approach has its anatomical limitations, advantages, and disadvantages.[6] The anteromedial approach is the most commonly used for distal tibial shaft reconstruction.
The main disadvantage is low blood supply to the skin and subcutaneous tissue which
can lead to exposed hardware. The anterolateral approach is used when the medial soft
tissues are compromised. The exposure is more difficult because of a risk of damaging
anterior tibial artery and deep peroneal nerve.[7] Classical osteosynthesis methods are developed to avoid exploration and to reduce
the risk of damaging lower limb blood vessels or nerves. To reconstruct the tibia
with a free or pedicle flaps, blood vessels have to be explored. Using dorsal osteosynthesis
approach, a good vascular exploration for microvascular anastomosis or pedicle flaps
is achieved.
The osteosynthesis hardware placed under microvascular free flap can be exposed if
total or even marginal skin necrosis occurs and reoperations with new flaps might
be necessary to close the defect and prevent infection. The dorsal osteosynthesis
approach was developed to secure metal plates and reduce a risk of failure. Skin flap's
paddle side can be healed by secondary intention without plate exposure. Of 11 patients
in our study, 5 were healed by secondary intention. No plate infections were observed.
Delayed postoperative complications include nonunion, recurrence or development of
osteomyelitis, failure of fixation, fibular fracture, sensory disturbances, contractures,
and deformities.[8]
[9] Graft fractures are the most common late postoperative complication. Previous authors
have found the incidence of fractures between 20 and 40%.[10] One patient in our study had a broken plate with bone fracture. Patient specified
that too early walking and exercises were applied on the reconstructed leg. The broken
plate was removed and reosteosynthesis done.
The dorsal osteosynthesis approach is developed for the tibia reconstruction with
pedicle or free bone (contralateral fibula, iliac crest). Treatment with contralateral
fibula is selected for the uncomplicated patients. In these cases double-barrel fibula
graft is preferred as fast recovery can be expected and patients can start physical
activities after cast is removed.
Pedicled fibulas are selected for complicated patients as there is higher risk for
below-knee amputation. Proximally or distally based pedicle fibula flap can be selected
depending on defect localization and vascularity. Fibula fractures are not contraindications
for flap selection. The same region operations are preferred for the high failure
risk patients as last chance operation before amputation. Salvage of the potential
donor side is a huge benefit for these patients as there is not any iatrogenic damage
in healthy side.
Conclusion
The dorsal osteosynthesis approach can be primary choice in cases when large soft
tissue defect is expected, which increases the risk of skin paddle necrosis, or as
a last reconstruction option if conventional reconstructions fail. Advantages of this
method are the following: incision can be made throughout healthy noncompromised tissue;
free access for anastomosis; contralateral fibula flap can be harvested from dorsal
side; pedicle vascularized fibula flap can be harvested through the same incision;
operation time does not increase; and in cases of partial tissue necrosis it can be
left for secondary healing.
In spite of small number of patients in our study, we need to continue our work to
evaluate the effectiveness of this approach with other methods.
