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INTRODUCTION
Distal femur fractures (DFF) (supra-condyle fracture, inter-condyle
fracture, medial condyle fracture, lateral condyle fracture) has a rate
from 6% - 7% among all types of femur fracture, of which supracondyle and inter-condyle fractures accounts for 70% of Distal femur
fractures cases. High-energy fracture (fracture caused by high-energy
force) is usually met on younger patients, fracture from traffic accidents
accounts for above 50%. Older patients usually have low-energy
fractures caused by falling. Conservative treatment for Distal femur
fractures has many disadvantages and complications, so surgeons prefer
open reduction and osteosynthesis through many methods:
intramedullary pin fixation (upstream or downstream from the knee);
osteosynthesis with plates and screws (normal plates and screws, two
plate/screw systems, DCS plate, femoral condyle plate and locking
plate). For complex cases, such as fractures occur near joints,
osteosynthesis with condyle plates, and recently, osteosynthesis with
locking plates has become the first choice, overcoming disadvantages of
other devices.
Although positive results were achieved in treatment of Distal
femur fractures, some studies show that: osteosynthesis with condyle
plates or locking plates still occurs fail (stiff knee, deflective healing,
delayed bone healing, pseudarthrosis…). For exact learning of fail
causes, we neeed to concern rigid fixation ability after surgery of these
plate types. Then, suitable exercise programmes after surgery are
established to avoid complications such as broken plate, screw flaking,
delayed bone healing, pseudarthrosis and sequelaes limiting movements
of knee joint. So, for comparison of rigid fixation ability between
condyle plate and locking plate on the same trial pattern in relation to
plate – bone connection, and eluvation of treatment effectiveness for
closed Distal femur fractures of locking plate, we did the thesis: “Study

and torsion forces of trial plate – bone model. It permits patients to
move early, reduces complications such as amyotrophy, delayed bone
healing, limited movement of knee joint.
Structure of the thesis: The thesis consists of 116 pages and
includes following parts: Introduction of 2 pages, Chapter 1 – literature
overview (32 pages); Chapter 2 – material and method (22 pages);
Chapter 3 – Result (27 pages); Chapter 4 – Discussion (30 pages),
Conclusion (2 pages) and Recommendation (1 page). There are 3
published studies related to the thesis.There are 125 references
including: 21 Vietnamese and 104 English documents.


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Chapter 1
LITURATURE OVERVIEW
1.1. Study of stiffness of locking plate on DFF fracture
osteosynthesis.
A study of Wilkens K.J et al (2008) showed that locking plate is
24,4% time more rigid than conventional plate, rigid rate of locking
plate/conventional plate is 168,2/127,1 N/mm; p
treated DFF fracture type C and compared 4 different osteosynthesis
measure types: Angel plate, DCS plate, condyle plate and locking plate.
Result: very good and good patient rates of locking plate, DCS plate,
angel plate and condyle plate were 86%, 78%, 66% and 50%
respectively. Vallier H.A et al (2012) compared Treatment outcome of
osteosynthesis between 950 angeled plate and LCP (Locking Condylar
Plate) during average follow up time of 26 months (9 - 77 months). For
some complications such as deep infection, non-healing and
displacement healing, complication rates of angeled plate and LCP were
10% and 35% respectively. Gupta SKV (2013) compared Treatment
outcome of osteosynthesis between intramedullary pin and LCP. After
6 months, his result showed that bone healing rates of both patient
group were above 75%, average bone healing time of intramedullary
pin and LCP groups were 6.8 and 7.5 months respectively. 2/46 (4%)
LCP patients had non-healing while there were 5/57 (9%)
intramedullary pin people with non-healing.
* In Vietnam: In recent years, Vietnamese surgeons have applied
locking plate to treat DFF fracture and achieve positive results:
Truong Tri Huu et al (2014) treated 34 patients with DFF fracture
by locking plate. Result: bone healing rate was 97.1%, while very
good, good, average and poor rates were 76.5%, 14.7%, 2.9% and 5.9%
respectively.


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Chapter 2
MATERIAL AND METHOD
2.1. A study on rigid fracture fixation ability of locking plate on a
bone combination model trial.

we could calculate force-bearing level of the models.
* Study content : Axial compressive force, Horizontal bending forc
Torsional bending force
* Method of evaluating the result: A graph was drawn and
average values of forces acting on the two study sample were calculated
by statistical algorithms of Hanoi University of Science and
Technology. Average values (Independent Sample T test) and medians
of forces acting on two samples were compared.
2.2. Study on treatment outcomes of DFF closed fracture using
locking plate osteosynthesis.
* Material: 54 patients (26 men, 28 women), with age ranging
from 18 - 90 years old and having DFF closed fracture caused by
trauma, received locking plate osteosynthesis at Duc Giang hospital,
Xanh Pon hospital, Military hospital 103 from June 2011 - 9/2015.
* Inclusion criteria: Patients with DFF closed fracture type A and
C caused by trauma.
* Clinical study method
- Method: longitudinal, non-controlled, descriptive study.
- Process: Collecting study records. Examinating patients.
Preparing patient before surgery. Do surgerical interventions and
surgical records. Doing post-operative care and X-ray examination.
Assessing near outcomes: outcomes of reduction and osteosynthesis
after surgery and process of incision. Patients was guided to do
rehabilitation. Follow-up sheet was made for each patient. Patients was
appointed to re-examine at following times: 1, 2, 3, 4, 5, 6 and 12
months after surgery and far outcomes (> 12 months) was aslo assessed.
- Content: Epidemiological characteristics. Cause and mechanism of
trauma. Taking X-rays before and after surgery, until bone healing
occured. Classification of DFF fracture based on X-ray images according
to AO classification. Surgical techniques, Locking plate osteosynthesis

Assessment of outcomes by 4 levels: Very good, good, average and poor.
* Methods of data processing: According to the medical statistics
program SPSS 20.0. Comparison between average values of study
groups (Independent Sample T test).
Chapter 3. RESULT
3.1.Results of trial study on mechanical strength and rigid
fracture fixation for DFF fracture of locking plate.


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3.1.1. Compressive strength trial on 2 samples: DFF locking plate bone (KA - N) and condyle plate - bone (LA - N).
Table 3.1: Compressive forces bearing ability on 2 samples of femoral
supra-condyle fracture (KA - N) and (LA - N) (n = 12)
Compres
Plate – bone sample with femoral supra-condyle fracture
sive
force
KA – N
LA – N
KA – N
LA – A
P
(X ± SD)
(Median
(X ± SD)
(Median
Fracture
- N)
(Newton - N)

Compres Plate – bone sample with femoral inter-condyle fracture
sive
KC – N
LC – N
force
KC – N
LC – N
P
(X ± SD)
(Median
(X ± SD)
(Median
Fracture
- N)
- N)
( Newton - N)
(Newton - N)
displace
(n=6)
(n=6)
ment
0.5 mm
1194.51 ± 210.07 1184.63
953.97 ± 287.56
995.22 > 0.05
1.0 mm 2030.63 ± 241.84 2028.99 1597.88 ± 527.67 1686.33 > 0.05
1.5 mm 3140.14 ± 288.16 3228.73 2738.34 ± 703.88 2919.65 > 0.05
2.0 mm
3915.8 ± 295.43 3968.29 3498.13 ± 787.61 3524.11 > 0.05
2.5 mm 4620.27 ± 315.85 4728.87 4139.28 ± 766.53 4322.23 > 0.05

KA – U
LA – U
KA – U
LA – U
(X ± SD)
(Media
(X ± SD)
(Median Fracture
n
N)
N)
(Newton - N)
(Newton - N)
displacement
(n=6)
(n=6)
1 mm
204.94 ± 70.34
178.04 155.86 ± 48.13
136.84
> 0,05
2 mm
396.37 ± 117.52 365.62 314.52 ± 88.88
340.30
> 0,05
3 mm
537.79 ± 121.16 508.07 499.78 ± 85.32
484.7
> 0,05
4 mm

SD)
SD)
(Media
(Media
( Newton - N)
( Newton - N)
Fracture
n - N)
n - N)
(n=6)
(n=6)
displacemen
t
1 mm
139.43 ± 39.09 137.38
105.3 ± 35.22
99.65
> 0,05
2 mm
271.34 ± 124.77 343.84
216.28 ± 97.57
226.3
> 0,05
3 mm
447.57 ± 107.14 499.22 416.75 ± 134.66 376.7
> 0,05
4 mm
699.26 ± 125.60 715.89
476.05 ± 59.18 492.44 < 0,05
Comment: From displacement of 4 mm, when broken connection

LA – X
Fracture
(Median (Media
(X ± SD)
(X ± SD)
displacemen
N)
n - N)
(Newton - N)
(Newton - N)
t
(n=6)
(n=6)
1 mm
421.64 ± 54.73
429.33
390.70 ± 81.15 419.76
> 0,05
2 mm
589.57 ± 88.51
608.27
533.90 ± 95.10 559.96
> 0,05
3 mm
777.02 ± 134.66
809.40
686.91 ± 80.48 699.84
> 0,05
4 mm
990.79 ± 166.54

( Newton - N)
(n=6)

KC – X
(Media
n - N)

LC – X (X ±
SD)
( Newton - N)
(n=6)

LC – X
(Media
n - N)

Fracture
displacemen
t
1 mm
514.21 ± 135.30
538.79
489.13 ± 81.64
464.88
> 0.05
2 mm
707.42 ± 213.60
691.70
664.43 ± 98.04
622.82

3.2. Treatment outcomes of DFF closed fracture using locking plate
osteosynthesis
3.2.1. Characteristics of studied patient group
Age and gender: Average age: 51.04 ± 22.30 years old (18 - 90
years old), male to female ratio: Male 26 patients (48.15%); Female 28
patients (51.85%). Elderly group ≥ 60 years old: 26 patients (48.15%),
group with age from 18 - 44 years old: 20 patients (37.04%), group of
45 - 59 years old: 8 patients (14.81%).
3.2.2. Accident’s causet: Daily activities accidents accounted for the
highest rate with 27 patients (50%), 24 patients with traffic accident was
(44.44%) and 3 people had labor accident (5.56%).


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3.2.3. Trauma mechanism: Direct and indirect mechanism had same
rate (50%).
3.2.4. Location, morphology and nature of injury
* Affected-side of thigh
Left DFF fracture of 30 patients (55.56%) was more than the right
fractur of 24 patients (44.44%).
* Nature of the fracture: Simple fracture: 31 patients (57.41%),
complex fracture: 23 patients (42.59%).
3.2.5. Classification of fracture according to AO
Table 3.10. Classification of fracture according to AO (n = 54)
Fracture
Type A
Total
Type C
Total


Labor
accident

18
6
24
44.44

2
1
3
5.56

Daily
activities
accident
22
5
27
50.0

3.2.6. Soft tissue injury
100% of patients had DFF closed fracture. No patient had open
fracture.
3.2.7. Accompanied injuries
Brain injury: 5 patients, chest injury: 2 patients, other fractures: 11
patients.

Total

3.2.10. Treatment outcome
3.2.10.1. Near outcome: * Incision: first phase incision healing: 53
patients (98.15%), superficial infection: 1 patient (1.85%). There was
no patient with deep infection or bleeding after surgery.
* Reduction outcome: Non-displacement: 50 patients (92.59%), less
displacement: 4 patients (3.70%).
* Bone healing outcome
Table 3.18. Duration of bone healing (n = 54)
Duration of bone healing
Min - Max
Group age
P
(week)


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18 – 30
14.39 ± 1.98
(12 – 18)
31 – 40
16.50 ± 4.95
(13 – 20)
41 – 50
17.00 ± 1.16
(16 – 18)
< 0,05
51 – 60
19.50 ± 1.76
(18 – 22)

> 70
6.83 ± 1.01
(5,00 – 8,00)
Comment: Average time to remove crutches: 5.20 ± 1.19 weeks
(from 4 to 8 weeks). The group of young people removed crutches
earlier than the elderly, the difference was statistically significant with p
70
5.58 ± 0.79

(89.47%), 4 patients had folding deformation 100
+ Short limbs: In our study, there were no case of short limbs.
+ Ability to walk after surgery:Walking as normal: 31 patients
(81.58%), walking from 30 – 60 minutes: 7 patients (18.42%).
+ Ability to go up stairs:Ability to go upstairs as normal: 28
patients (73.68%), using handrail 10 patients (26.32%).
+ Ability of working and doing daily activities:27 patients (young
people worked and elderly did daily activities normally - 71.05%); 7
patients (young people worked hard and elderly people needed to be
supported partly – 18.42%). There were 4 patients (young people had
to change previous jobs and elderly people had be supported with living
activities - 10.53%).
3.2.10.3. Far outcome after surgery


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* Assessment of far outcome according to AO fracture
classification
Table 3.30. Assessment of far outcome according to AO fracture
classification (n = 38)
Rate
Group A
Group C
Result
Total
%
A1 A2 A3
+ C1 C2 C3

13
4
26
3
7
2
12
38
100
Comment: Type A: Very good: 18 patients (47.36%), good: 8
patients (21.05%),
Type C: Very good 4 patients (10.53%), good: 4 patients (10.53%),
average: 4 patients (10.53%)
* Assessment of common outcome:
Comment: Very good 57.89%, good: 31.58%, average: 10.53%,
poor: 0 patient.
Chapter 4
DISCUSSION
4.1. Rigid fracture fixation ability rigid DFF fracture of locking
plate
* Compressive strength of DFF locking plate – bone sample:
From displacement of 2.5mm on femoral supra-condyle fracture model,
the forces acting on the DFF locking plate – bone and femoral condyle
plate – bone samples were 4010.37 ± 509.50N (medium 4179.34N) and
3200.04 ± 243.62N (Median 3118.63N) respectively. The difference
was statistically significant with p < 0.05. From displacement of
2.5mm on femoral inter- condyle fracture model, the forces acting on the
DFF locking plate – bone and femoral condyle plate – bone samples
were 4620.27 ± 315.85N (median: 4728.87N) and 4139.28 ± 766.53N
(median: 4322.23N) respectively. The difference wasn’t statistically

wasn’t statistically significant with p > 0.05. .
4.2. Treatment outcome of DFF closed fracture using locking plate
osteosynthesis
4.2.1. Common characteristics of studied group
* Age, gender: There were 54 patients with DFF closed fracture,
average age: 51.04 ± 22.30 years old (18 - 90 years old), male: 26
patients (48.15%); female: 28 patients (51.85%), male to female ratio
was nearly equal. Elderly group ≥ 60 years old: 26 patients (48.15%),
group with age from 18 - 44 years old: 20 patients (37.04%), group of
45 - 59 years old: 8 patients (14.81%).


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* Cause and mechanism of trauma: Daily activities accident: 27
patients (50%), elderly group ≥ 60 years old: 18/27 people, group of 18
- 44 years old: 4/27 people and group of 45 - 59 years old: 5/27 people.
Traffic accident: 24 patients (44.44%), group of 18 - 44 years old: 15/24
people, group ≥ 60 years old: 6/24 people and group of 45 - 59 years
old: 3/24 people. Labor accident: 3 patients (5.56%), all of them were
young people. Number of patients with left and right DFF fracture were
30 (55.56%) and 24 (44.44%) respectively.
* Characteristics, natures and classification of fracture: Simple
fracture: 31 patients (57.41%), complex fracture: 23 patients (42.59%).
Non-articular fracture: 42 patients (77.78%), articular fracture: 12
patients (22.22%).
4.2.2. Indications of locking plate osteosynthesis: DFF closed fracture
of type A and C (according to AO classification), articular and complex
fractures. Same-side proximal tibia fracture. DFF fracture in elderly
patients, people with osteoporosis.

Surgery duration from 60 - 90 minutes (87.04%), type A: 39 patients,
type C: 8 patients. Surgery duration from 90 - 120 minutes: 5 patients
(9.26%), both surgery durations of 120 - 150 minutes and 150 - 180
minutes had 1 patient (1.85%). There was no patient with surgery
duration > 180 minutes.There were 36/54 patients receiving transfusion
with total blood volume of 18200 ml.
4.2.5. Assessment of treatment outcome of DFF fracture
* Bone healing: long outcomes of 38 patients were followed up
more than 12 months, average follow-up time: 34.58 ± 8.38 months
(from 12 to 48 months), average healing time: 18.33 ± 3.78 weeks
(from 12 - 26 weeks). No patient had pseudarthrosis, delayed healing
and non-healing.
* Result of rehabilitation: Thanks to rigid locking plate
osteosynthesis and rehabilitation, in our study group, the patient could
walk early without crutch, the earliest as 4 weeks, and the latest as 8
weeks, the average time to remove crutch was 5.20 ± 1.19 weeks.
Young people could walk without crutch earlier than the elderly, even in
case young patients with complex fractures, the difference was
statistically significant with p < 0.05.
* Result of osteosynthesis to anatomy recovery: non-displacement:
50 patients (92.59%), less displacement: 4 patients (7.41%, seen in
patients with type C fracture), no folding deformation: 34 patients
(89.47%), folding deformation with angle 10 0 and
no case with short legs.


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* Result of knee-joint rehabilitation. In the study, knee movement

- Degenerative joint: 0 case.
CONCLUSION
By studying rigid fracture fixation ability of compressive locking
plate on experimental model at Hanoi University of Science and


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Technology and evaluating treatment outcomes of 54 patients with DFF
closed fracture of type A and C (according to AO) with locking plate,
we had some conclusions:
1. Determination of rigid fracture fixation ability rigid of
compressive locking plate on experimental model.
- Femoral supra-condyle fracture model: There is broken plate –
bone connection with: Compressive force: 4010.37 ± 509.50N (median:
4179.34N), converted stiffness: 1269.74N / mm (displacement of
2.5mm); Horizontal bending force: 704.33 ± 110.45N (median:
704.08N), converted horizontal bending stiffness 332.92N / mm
(displacement of 4mm); Torsional bending force: 990.79 ± 166.54N
(median: 991.69N), converted torsional bending stiffness: 379.42N /
mm (displacement of 4mm).
- Femoral inter-condyle fracture model: There was broken plate –
bone connection with: Compressive force: 4620.27 ± 315.85N (median:
4728.87N), converted compressive stiffness: 1814.19N / mm
(displacement of 2.5mm); Horizontal bending force: 699.26 ± 125.60N
(median: 715.89N), converted horizontal bending stiffness 373.22N /
mm (displacement of 4mm); Torsional bending force: 1071.00 ±
222.38N (median: 1091.79N), converted torsional bending stiffness:
379.42N / mm (displacement of 4mm).
On the same experiment model, DFF locking plate had a more rigid

- Technique: Lateral incision: 22 patients (40.26%): Simple
femoral supra-condyle fracture, the incision through inter-muscular
septum, ensuring whole injure was observed, less invasive, avoiding
important nerve and vascular bundles. The incision was wide
enough to not hinder operation of surgeons.
- Anterolateral incision: 32 patients (59.74%): Complex femoral
supra-condyle fracture, femoral inter-condyle fracture with medial
condyle injury needing rehabilitation.
- For complex DFF fracture, butterfly fracture, oblique fracture,
torsional fracture, articular fracture, reduction was used with steel
suture and screw to fix fracture. Then, locking plate was placed and
locking screws were inserted.