knee joint and knee joint replacement

1. KNEE JOINT REPLACEMENT
Presented by Dr.Nagy Youssef Mohammed

3. KNEE JOINT

4. Knee involved bones

5. KNEE ANATOMY
-THE KNEE JOINT IS THE LARGEST & MOST COMPLICATED JOINT
IN THE BODY .
- It consists of 3 Joints within a single
synovial cavity :

6. 1) Medial Condylar Joint :
Between the medial condyle
“of the femur” & the medial
condyle “of the tibia” .
2) Lateral Condylar Joint :
Between the lateral condyle
“of
the femur” & the lateral
condyle “of the tibia” .
3) Patellofemoral Joint :
Between the patella & the
patellar surface of the femur .
-The fibula is NOT directly
involved in the joint .
Types of articulation :
- 1 & 2 : Hinge .
- 3 : Planar gliding .
(Knee joint of right leg)

7. Anatomical Components of the Knee :
A) Capsule : is thin
Surrounds the sides & posterior
aspect of the joint.On the frontal
side , the capsule is absent .
On each side of the patella , the
capsule is strengthened by two
tendons.
Synovial membrane lines the
capsule & attaches to the margins
of the articular surfaces.

8. B)Ligaments :there is four extracapsular ligaments & two
intracapsular ligaments .
3)Tibial (medial)
collateral
ligament
2)Fibular (lateral)
collateral
ligament
1)Patellar ligament
1)Extracapsular ligament :

9. 3)Tibial (medial)
collateral
ligament
(weak and more
liable to injury)
4)Oblique
popliteral
ligament
(strengthens the
posterior side of the
capsule)
2)Fibular
(lateral)
collateral
ligament
(strong and less
liable to injury)

10. 2)intracapsular ligaments : Cruciate Ligaments : 2 strong ligaments that
cross each other within the joint cavity.
Anterior Cruciate
Ligament(ACL)
(it limits
hyperextension of
knee joint)
Tear : common
during severe
hyperextension.
(‫الصليبي‬ ‫الرباط‬
‫االمامي‬)
Posterior
Cruciate
Ligament (PCL)
(it limits
hyperflexion of
knee joint )
Tear : are rare.

11. The medial and lateral menisci : are
intracapsular structures , 2 C - shaped sheets of
fibrocartilage between the tibial & femoral condyles. They
are connected to each other by the transversa
ligament.

12. Medial meniscus:
firmly attached to capsule and
tibial (medial) collateral
ligament .more liable to injury
(fixed).
The lateral meniscus:
Separated from capsule and
fibular (lateral) collateral
ligament. Therefore it is more
likely to move rather than tear.
(mobile).
Function of two menisci:
1)Absorb shocks.
2)Adapt tibial condyles to femoral condyles.
3)Lubricate articular surface with synovial
fluid.

13. ESSENTIAL KNEE JOINT LIGAMENTS :
MCL (medial collateral ligament) :
-when stress applied ligament aids control transferring the joint
through normal range of movement.
-MCL prevents an anterior movement of tibia and
hyperextension.
-MCL resist vulgus forces applied to knee through all degree of
flexion.
-Partial or complete ruptures in MCL significantly increase load
on ACL (anterior cruciate ligament).
LCL (lateral collateral ligament ):
Resist varous stress .
PCL & ACL : they cross each other to form X . They have role in
knee stability.

14. Anatomy of patella (knee cap ):
Thick, circular-triangular bone which articulates with the femur
and covers and protects the anterior articular surface of the
knee joint. It is the largest sesamoid bone .

15. Knee Movements:
1)Flexion: limited by the
contact of the back of the
leg with the thigh. The
maximum hyperflexion
around 150°.
2) Extension : limited
by the tension of all the
ligaments of the joint .
The maximum
hyperextension is 0 °.

16. Abnormal case of hyperextension

17. 3) Medial Rotation :inward the body.
4) Lateral Rotation : outward of the body.
(Both are performed when knee is flexed).

18. KNEE JOINT REPLACEMENT

19. KNEE REPLACEMENT SURGERY:
Joint replacement surgery is a safe and effective procedure to
relieve pain, correct leg deformity, and help you resume
normal activities.
Knee replacement surgery was first performed in 1968. Since
then, improvements in surgical materials and techniques
have greatly increased its effectiveness. Total knee
replacements are one of the most successful procedures in
all of medicine. According to the Agency for Healthcare
Research and Quality, more than 600,000 knee
replacements are performed each year in the United States.

20. Knee joint replacement surgery :is considered
for patients whose knee joints have been damaged by either
progressive arthritis, trauma, or other rare destructive
diseases of the joint. The most common reason for knee
replacement is severe osteoarthritis of the knees.

21. Why do people have
knee replacement
surgery?
For the majority of people
who have knee
replacement surgery,
the procedure results in:
 a decrease in pain.
 increased mobility.
 improvements in
activities of daily living.
 improved quality of life.

22. PREOPERATIVE PLANNING :
- Determine angle between
anatomical axis and mechanical
axis to determine valgus angle.
- Angle determine for both knees.
The valgus angle of a healthy
knee joint is 5°–7°.
- this angle must be determined
before carrying out the distal
femoral resection.
- The appropriate implant size can
be selected preoperatively with
X-ray templates.
Anatomic axis: (center of knee
joint & intramedullary canal)
Mechanical axis: center of femoral
head, center of knee joint &
center of ankle to second toe.

23. A)INCISION AND EXPOSURE :
1)Prior to incision, the superior pole of
the patella is marked with the knee
flexed at 30°.The tibial tubercle is
identified and marked.
2) An anterior midline longitudinal incision
is made.
Be cautious :
- not to transect the quadriceps in
thinner patients with a small
quadriceps tendon, as this could
compromise postoperative
rehabilitation protocols.
-

24. A)INCISION AND EXPOSURE CONT. :
3) Extend the leg and excise the fat
pad under the patella tendon .
4)Retract the patella laterally with the
knee in extension and release the
patellofemoral ligaments.

25. A)INCISION AND EXPOSURE CONT. :
4)Retract the patella
laterally with the knee in
extension and release
the patellofemoral
ligaments.

26. A)INCISION AND EXPOSURE CONT. :
5) Release the anterior cruciate
ligament and remove the
medial and lateral
meniscus.
- This will allow further edge
exposure of the proximal tibia.

27. B)TIBIAL PREPARATION:
There are two options for tibial preparation:
- extramedullary (EM) referencing alignment .
- intramedullary (IM) referencing alignment.

28. B)TIBIAL PREPARATION CONT.:
Rotation definition and
axial alignment: to
determine the correct
alignment rotation we use
Alignment instrument,
centrally along tibial shaft axis
and in extension line onto the
second toe.

29. B)TIBIAL PREPARATION CONT.:
Resection adjustment :
Tibial saw guide , pushed against
ventral tibial cortical bone.
Dorsal slope: recommended dorsal
slope 5°(a).
Varus valgus adjustment : the fine
adjustment(b) allows precise
correction of varus or valgus
alignment.
Tibial resection height: determine
the required resection height with
stylus (c).

30. B)TIBIAL PREPARATION CONT.:
Tibial resection :
Cutting template , used to check
alignment of the tibial resection
(fig.1).
Any corrections can be at this
point.
- Then cutting block is fixed with
pins and resection is performed
- ( fig.2&3).

31. B)TIBIAL PREPARATION CONT.:
Determining the tibial size :
anterior fixation pins remain in
position.(fig.1).
- Determine tibial implant size by
applying the appropriate tibial
sizer, the instrument must cover
cortical bone optimally (fig.2&3).
- The tibial implant size can also
serve as an indicator for the
femoral implant size if the femoral
measurement is between two
sizes.

32. B)TIBIAL PREPARATION CONT.:

33. B) FEMORAL PREPARATION :
Distal resection:
- opening the femoral medullary space:
knee is flexed to 90 ° to reset femur.
- Using the femoral step drill, make an
entry hole into the medullary canal of
the femur (Fig A.). Entry point located
approx.3-5 mm medially above the
intercondylar fossa.
Predetermining the femoral size :
The intramedullary guide rod is inserted
and the T-handle is removed (figs.B).
(A
)

34. B) FEMORAL PREPARATION CONT.:
Distal resection cont. :
The femur measuring
instrument is attached,
aligning the stylus laterally on
the ventral cortical bone (fig.1).
first predetermination of the
femoral size is carried out in
order to select the appropriate
distal femoral resection
guide.

35. B) FEMORAL PREPARATION CONT.:
Distal resection cont. :
the distal cutting block is connected to
the alignment instrument for valgus
angle. Then, the preoperatively
determined valgus angle is set, and the
instrument is attached to the
intramedullary guide rod .
-Before fixing the distal cutting block with
two fixation pins, it must be ensured
that.
1)At least one condyle is in contact with
alignment.
2)The valgus angle of the correct side has
been set.

36. B) FEMORAL PREPARATION CONT.:
3)Distal femoral valgus
angle preparation cont.:
- Use the oscillating saw to
make the distal femoral face
cut.

37. B) FEMORAL PREPARATION CONT.:
-The parallel fixation pins remain
in position (fig.1).

38. CHECKING THE EXTENSION GAP AND AXES:
the spacer is inserted, according to
the femoral size, and both the axial
alignment and the stability of the
joint in extension are checked.

39. B) FEMORAL PREPARATION CONT.:
Final Femoral Resection :
Determining the femoral size For final
femoral resection, The femur
measuring instrument is applied
to the distal femoral resection
surface.
-Two fixation pins are used to fix the
size and, at the same time, to fix
the frame of the measuring
instrument to the distal resection
surface.

40. B) FEMORAL PREPARATION CONT.:
Rotation setting :

41. B) FEMORAL PREPARATION CONT.:
The flexion gap can be checked
before finally defining the rotation
setting and the femoral resection.

42. B) FEMORAL PREPARATION CONT.:
Once the correct rotation has been set,
the instrument is fixed with two
fixation pins through the medial and
lateral holes . These fixation pins
are the guide reference for the
position of the femoral cutting
block.
- The alignment instrument is
removed, but the two fixation pins
remain fixed in the bone.

43. B) FEMORAL PREPARATION CONT.:
A/P femoral resection and
facet surfaces :
-The ventral cut is carried out first,
followed by the dorsal, then the
anterior and posterior facet cuts

44. B) FEMORAL PREPARATION CONT.:
Completing the femoral
preparation cont.:

45. B) FEMORAL PREPARATION CONT.:
Final Femoral
Resection

46. B) FEMORAL PREPARATION CONT.:
Be careful not to transect the attachment of the medial (tibial)
collateral ligament or the lateral (fibular) collateral ligament during
resection of the posterior condyles.

47. B) FEMORAL PREPARATION CONT.:
Be careful not to transect the attachment of the medial (tibial)
collateral ligament or the lateral (fibular) collateral ligament during
resection of the posterior condyles.

48. PATELLA PREPARATION :
- The preparation of the
patella should be done with
the patella everted and the
knee flexed to 30°. The
minimum thickness of the
resected patella should be
8mm.(fig.1).
- After the patellar surface is
resected , use the patellar
drill guide (fig.2) to assess
the size of the patella .
- By peg drill ,drill three
holes in the remaining
patellar bone. Place the
patella trial (fig.3).

49. TRIAL REDUCTION AND GAP BALANCING
Perform a trial reduction of the
components (Fig. ). Check
stability, extension,
patellofemoral tracking,
anteroposterior stability and
flexion degrees. Use a gap
balancing chart to adjust and
modify any imbalance in the
knee.

50. IMPLANTATION :
- It's recommend the following order of
implantation.
1. Tibial component
2. Femoral component
3. Patellar component
4. Tibial articulating surface
- Mixing bone cement under vacuum
and add tobramycin for decrease
incidence of infection.

51. IMPLANTATION CONT.:
Tibial component:
-Place cement on the
undersurface of the tibial
component and on the
bottom of tibial component
and firmly impact the tibial
component (Fig. ) into
place using the tibial
impactor. Remove excess
cement.

52. IMPLANTATION CONT.:
Femoral component :
- Hyperflex the knee and dry
the distal femoral bone
cuts.(fig.1).
- Apply bone cement (fig.2) .
Firmly impact the femoral
component into place using
the femoral impactor(fig.3).
Remove excess cement.

53. IMPLANTATION CONT.:
Tibial articulating surface:
Firmly impact the selected articular
surface liner into place (Fig.)
and check to see that the
locking mechanism is engaged
.

54. IMPLANTATION CONT.:
Patellar component :
Reduce the knee and place
into extension. Evert the
patella. Dry the bony
surface of the patella.
Apply bone cement(fig.1) .
Place the patella implant in
the resected bone. Use the
patella clamp to secure the
patella implant (Fig. 2).
Trim excess osteophytes
and remove excess
cement.

55. Closure is performed in the usual manner

56. POSTOPERATIVE:
knee replacement patients are able to leave the hospital
within 1 to 5 days (often 2 or 3), and they can take care of
themselves and resume most activities 6 weeks after
surgery. The majority of patients are 90% recovered after 3
months, though it can take 6 months or longer before they
are 100% recovered.
- -Patients will start walking using a walker and crutches.
- - A number of home exercises are given to strengthen thigh
and calf muscles.

57. Physical therapy is an extremely important part of
rehabilitation and requires full participation by the patient for
optimal outcome. Patients can begin physical therapy 48
hours after surgery.

58. REFERENCES:
 https://orthoinfo.aaos.org/en/diseases--conditions/patellar-tendon-tear/
 http://www.innerbody.com/image/skel16.html
 https://www.medicinenet.com/image-
collection/knee_joint_picture/picture.htm
 http://www.innerbody.com/anatomy/skeletal/leg-foot/knee-joint-posterior
 https://www.slideshare.net
 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3167403/
 http://www.maxxmed.com/us/freedom-total-knee-system-landing-maxx-
medical.php
 https://www.medicinenet.com/total_knee_replacement/article.htm#how_
does_the_patient_continue_to_improve_as_an_outpatient_after_dischar
ge_from_the_hospital_what_are_recommended_exercises
 https://orthoinfo.aaos.org/en/recovery/total-knee-replacement-exercise-
guide/
 http://www.innerbody.com/image/skel16.html