Total knee replacement (TKR) involves replacing the weight-bearing surfaces of the knee joint to relieve pain and correct deformities. The document discusses the anatomy of the knee joint, common conditions requiring TKR such as osteoarthritis and rheumatoid arthritis, the evolution of TKR implant designs, surgical approaches, the procedure, goals of alignment and balancing, and potential complications. Computer-assisted technology can provide real-time feedback on bony cuts and alignment during surgery. While TKR successfully relieves pain in most patients, some may still experience complications such as stiffness, infection, or loosening of implants.
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Tkr by dr. saumya agarwal
1. TOTAL KNEE REPLACEMENT
Presenter : Dr. Saumya Agarwal
Junior resident Dept of Orthopaedics
J.N .Medical College and Dr. Prabhakar
Kore Hospital and MRC, Belgaum
2. INDEX
⢠Anatomy of the knee joint
⢠Common conditions leading to TKR
⢠Evolution of TKR
⢠Total knee replacement
8. ďOsteokinematics
Gross movements of bones at joints
Flexion / extension
Abduction / adduction
Internal rotation / external rotation
ďArthrokinematics
Small amplitude motions of bones at joint surface
Roll
Glide (or slide)
Spin
9. INTRODUCTION
Arthroplasty is the surgical reconstruction of a
joint which aims to relieve pain , correct
deformities and retain movements of a joint.
Total Knee Arthroplasty(TKA) is the surgical
procedure to replace the weight-bearing
surfaces of the knee joint.
10. Common Conditions That Lead To TKR
⢠OSTEOARTHRITIS
Primary (idiopathic)
Secondary
Post traumatic arthritis
⢠RHEUMATOID ARTHRITIS
11. Evolution of TKR
⢠Fergussen(1860) resection arthroplasty
⢠Verneuil performed first interposition arthroplasty
⢠1940s- first artificial implants were tried when molds
were fitted in the femoral condyle
⢠1950s- combined femoral and tibial articular surface
replacement appeared as simple hinges
12. Evolution âŚ.
⢠Frank Gunston(1971), developed a metal on
plastic knee replacement
⢠John Insall(1973), designed what has become
the prototype for current total knee
replacements. This was a prosthesis made of
three components which would resurface all 3
surfaces of knee - the femur, tibia and patella
13. Classification of Implants Design
⢠Unconstrained
â Cruciate retaining
â Cruciate substituting
â Mobile bearing knees
⢠Constrained (Hinged)
⢠Unicondylar Prosthesis
⢠Total Condylar Prosthesis
17. Cruciate stabilized
⢠Cam and post mechanism
⢠Insert more congruent / dished
Advantages
Easier to balance knee
More range of motion
Disadvantages
Cam jump
Post wear
Patellar clunk syndrome
Additional cut from distal femur
ABSOLUTE INDICATION
â˘Previous patellectomy
â˘Inflammatory arthritis
â˘Deficient PCL
18. Cruciate sacrifice / retain - Evidence
PS increased ROM â
No functional improvement
No difference in ROM
between PS and CR
PCL does not work in CR
knees
Increased wear Ps knee â
cam & post
Cochrane review â No difference in
function whether cruciate retained
or sacrificed
19. Mobile Bearing Design
⢠Poly Rotates over tibial
base plate
⢠Reduced poly wear
⢠Bearing spin out
20. Fixed Bearing or mobile bearing -
Evidence
⢠No advantage of mobile bearing over fixed
bearing
⢠Increased wear in undersurface of mobile
bearing
22. Constraint
â Ability of prosthesis to provide varus â valgus and
flexion âextension stability in presence of
ligamentous laxity / bone loss
23. Constrained Hinged design
⢠Linked femoral and
tibial components
⢠Tibial bearing rotates
around yoke
Aseptic loosening
Large amount bone
resection
INDICATION
Global ligamentous
deficiency
Hyperextension instability
24. Hi Flex Design
⢠Cultural / pt expectation
⢠Cut more posterior
condyle
Preop flexion - most significant - Gatha etal 2008
No difference in ROM - Mehin JBJS 2010
No difference in ROM Sumino Int Ortho 2010
26. Advantages of Unicondylar TKR
⢠Shorter rehabilitation time
⢠Greater average post-op range of movement
⢠Preservation of proprioception function of
cruciate ligaments
27. CONTRA-INDICATIONS
a) Inflammatory conditions
b) Damage to articular cartilage
c) Flexion contracture of 5° or more
d) Preoperative arc of motion less than 90°
e) Angular deformity of more than 15°
f) ACL deficiency
28. Total Knee Replacement Today
⢠Large variety is available
⢠Majority of TKR today are condylar
replacements which consist of the following
â Cobalt-chrome alloy femoral component
â Cobalt-chrome alloy or titanium tibial tray
â UHMWPE tibial bearing component
â UHMWPE patella component
29. Who Is A Candidate For TKR
⢠Quality of life severely affected
⢠Daily pain
⢠Restriction of ordinary activities
⢠Evidence of significant radiographic changes of
the knee
30. INDICATIONS
⢠Severe arthritis
⢠Young pts with systemic arthritis with multiple joint
involvement
⢠Osteonecrosis with subchondral collapse of a
femoral condyle
⢠Severe pain from chondrocalcinosis and pseudogout
in elderly
⢠Severe patello femoral arthritis rarely
31. CONTRA-INDICATIONS
⢠Recent/current knee sepsis
⢠Remote source of ongoing infection
⢠Extensor mechanism discontinuity
⢠Recurvatum deformity secondary to muscle weakness
⢠Presence of painless, well functioning knee arthrodesis
32. What Is The Time For Replacement
⢠Old age with more sedentary life style
⢠Young patients who have limited function
⢠Progressive deformity
⢠Other treatment modalities have failed
33. TKR should be done before things get out of
hand and the patient experiences a severe
decrease in ROM, deformity, contracture,
joint instability or muscle atrophy
34. Evaluation Of Patient Before Surgery
⢠A Complete Medical History
⢠Thorough Physical Examination
⢠Laboratory Work-up
⢠Anesthesia Assessment
34
35. Recommended Preoperative Radiographs in
Knee Replacement Surgery
1. Standing full-length anteroposterior radiograph
from hip to ankle
2. Lateral knee x ray
3. Merchantâs view
36. Radiographs
⢠Standing Ap & Lateral
⢠Sunrise â Merchant view
⢠Hip to ankle x- rays
â Bony deformity
â Short stature ( < 150 cm)
â Very tall ( > 190 cm)
37. Radiographs
⢠Femoral and tibial cut
⢠Position of femoral canal entry
⢠Bone defects
⢠Joint subluxation
⢠Ligament stretch out â Varus Thrust
⢠Ligament release
⢠Constraint needed
38. Goal of TKR
⢠Pain relief
⢠Restoration of normal limb alignment
⢠Restoration of a functional range of motion
40. Technical Goals Of Knee Replacement
Surgery
1. The restoration of mechanical
alignment
2. Preservation (or restoration) of the joint
line
3. Balanced Ligaments
4. Maintaining or restoring a normal Q angle
41. Mechanical Alignment
TKA aims at restoring
the mechanical axis of
the lower limb by:
ďSequential soft
tissue releases
ďCorrection of bone
defects by grafts or
prosthetic augments
42. Ligament Balancing
a. Coronal Plane
â For varus deformities
â For valgus deformities
b. Sagittal Plane
â Flexion contractures
â Extension contractures
56. Subvastus approach
⢠Vastus medialis lifted off
Lateral intermuscular
septum
Advantages
Intact quad
Preserved vascularity of
patella
Disadvantage
Least extensile
Denervation of VMO
possible
57. Femoral Cut
⢠Valgus cut angle
⢠AAF â MAF
⢠Between 5 â 7 deg
⢠Intramedullary guide
58. Tibial Cut
⢠Angle between AAT â
MAT
⢠Tibial cut angle- Zero
⢠Tibial deformity â cut
perpendicular to MAT
⢠Intra or extramedullary
guide
59. Joint line preservation
⢠Inserting prosthesis same size as removed bone
and cartilage
Elevate joint line -
mid flexion instability
Abnormal patellofemoral tracking
Equivalent to Patella Baja
Lowering joint line -
Lack of full extension
60. Knee Balancing
⢠Balance in Coronal and
saggital plane
⢠Concave side â
ligaments contracted â
release
⢠Convex side â ligaments
stretched â Fill gap
71. Saggital plane balancing
⢠Mc Phersonâs rule
Symmetric gap â address tibia
Asymmetric gap â address femur
72. Tight in Extension
Tight in flexion
Symmetric gap Cut more tibia
Loose in Extension
Loose in Flexion Symmetric gap
â˘Thicker poly
â˘Tibial Metal
augmentation
73. Extension good
Loose in flexion
Asymmetric gap
1. Increase size
femoral
component
2. Translate
femoral
component
posterior
3. Use thicker
poly and
readdress as
tight extension
gap
81. Patellar component
⢠Centre or medialized
⢠Avoid lateralizing
⢠Increases Q angle and
cause patella
maltracking
82. Patella Baja
⢠Patellar component
superior
⢠Lower joint line
⢠Transfer tibial tubercle
cephalad
⢠Patellectomy
83. Patella resurfacing vs non resurfacing
⢠Resurfacing
â Component loosening
â Clunk
â Fracture
â AVN
⢠Non resurfacing
â Anterior knee pain
â May require second
resurfacing
84. Patellar resurfacing Vs non resurfacing
- Evidence
⢠Metal backed patella higher complications
⢠Patellar replacement does not gurantee
painless Patellofemoral joint
⢠No significant benefit of patellar replacement
86. Complication
Peroneal Nerve palsy ( .3 to 2 %)
Pre op Flexion and Valgus
Tourniquete time > 120 min.
Epidural anaesthesia post op
Aberrant retractor placement
EMG & NCV at 3 months
Nerve decompression at 3 months
91. Summary
⢠Choose correct pt
⢠Plan properly
⢠Adequate exposure
⢠Follow principles to align and balance knee
⢠Meticulous closure
Hope for the best
because 20 % of pt.
with well performed
TKR are not happy !!
92. Post Operative Rehabilitation
â Rapid post-operative mobilization
⢠Range of motion exercises started
⢠CPM
⢠Passive extension by placing pillow under foot
⢠Flexion- by dangling the legs over the side of
bed
⢠Muscle strengthening exercises
⢠Weight bearing is allowed on first post op day
93. Prosthesis Survival
Different studies shows different results
⢠Ranawat et al (Clin Orthop Relat Res )
95% at 15 years
91% at 21 years
⢠Gill and Joshi (Am J Knee Surg)
96% at 15 years
82% at 23 years
⢠Font-Rodriguez (Clin Orthop Relat Res )
98% at 14 years
94. COMPUTER-ASSISTED ALIGNMENT
TECHNIQUE
⢠The technique involves the attachment of active or
passive trackers on femur and tibia, which are then
tracked by a computer-assisted camera.
⢠Computer gives real-time feedback about alignment
of bony cuts in all three anatomic planes, which
allows surgeon to make changes and to measure
the accuracy of the bony cuts.
95. ⢠Computer navigation systems also can aid in
determining the proper implant size as well as
alignment. Soft tissue balancing and measurement
of flexion and extension gaps during the procedure
are other significant advantages to computer-
assisted TKA.
⢠Objective measurement of the gaps ensures proper
soft tissue balancing and gaps that will provide a
stable joint throughout a range of motion.
⢠Another advantage of computer navigation is
avoidance of violation of the femoral intramedullary
canal, which may reduce blood loss and cardiac-
related complications because fewer emboli are
placed into the venous system than with placement
of an intramedullary alignment rod.
96. Questions in exams ??
Long Question?
1) Describe in detail about the kinematics of knee and
enumerate the indications, procedure and complications
of TKR
Short Questions?
1) Approaches for TKR
2) Hi flexion type implant in TKR
3) Computer assisted technology for TKR
4) Complications post TKR
Hinweis der Redaktion
In todayâs talk we will discuss brief anatomy of the knee joint, and then about the common knee problems that may lead to tka surgery. I will talk about brief history of TKR. then we will discuss how tkr is performed. At the end I will show u few cases of TKR done in our unit during the last one year.
But first, lets review the anatomy of the knee joint
The bony anatomy of the knee joint includes the distal femur, the proximal tibia and the patella. The knee joint is a tricompartmental joint and consists of a patellofemoral articulation and medial and lateral femorotibial articulations.
The knee joint has no inherent stability rather it is provided by the surrounding ligaments and muscles.The ligaments about the knee include the collateral ligaments and the cruciate ligaments.the medial and lateral cpllateral ligaments prevent valgus and varus stresses, respectively. The anterior and posterior cruciate ligaments prevent anterior and posterior tibial traslation on the femur and secondary restraint to rotation. Fibrocartilagenous medial and lateral meniscus provides stability and shock absorption , especially with axial loading.
Knee motion during normal gait is more complex than simple flexion and extension. It occurs in abduction adduction, internal and external rotation and obviously the flexion and extension
The most common conditions that can lead to TKR are osteoarthritis which may be primary and secodary and the rheumatoid arthritis. Arthritic conditions can be classified as non inflammatory and inflammatory types. The classic type of non-inflammatory diseases are primary osteoarthritis and pot traumatic arthritis. The classic type of inflammatory arthritis is rheumatoid arthritis. The other types include gout, arthritis of psoriasis, ankylosing spondylitis etc.
1860- fergussen reported performing a resection arthroplasty of the knee for arthritis
Few years later- verneuil performed first interposition arthroplasty using join capsule. Other substances were subsequently tried including muscle, fascia an fat. 1940-but these designs had problems with loosening and persistent pain. 1950s-These implants failed to account for the complexities of knee motion and consequently had high failure rates from aseptic loosening. They were also associated with unacceptably high rates of postoperative infection.
In 1971, Gunston importantly recognized that the knee does not rotate on a single axis like a hinge, but rather the femoral condyles roll and glide on the tibia with multiple instant centers of rotation. His polycentric knee replacement had early success with its improved kinematics over hinged implants but was unsuccessful because of inadequate fixation of the prosthesis to bone. In 1973 total condylar prosthesis was designed by Insall at the hospital for special surgery and this desighn is basically the model used today
There are 2 broad categories of implants design used for TKR
Un-constrained> most common type, used for un complicated knee problems, artificial components inserted into the knee are not linked to each other, have no stability built into the system, relyes on the personâs own ligaments and muscles.
Constrained> rarely used as a first choice, knee joint linked with a hinge, used when knee is highly unstable, useful in severly damaged knees, it is not expected to last as long as other types.
Unicondylar> replaces only half of the knee joint when damage is limited to one side of the knee,
1-Cobalt-chrome alloy femoral component replacing femoral condyles and the patella trochlea. Cobalt-chrome alloy or titanium tibial tray affixed to the upper tibia. UHMWPE tibial bearing component fixed into the tibial tray. UHMWPE patella component
When the quality of life is such that they are willing to undertake the risks of major surgery. Any arthritic disorder of the knee that is nonresponsive to the usual nonoperative treatment, when the patientâs pain is such that he or she can no longer accomplish his or her required activities of daily living. Before surgery is considered, conservative treatment measures should be exhausted. Destruction of knee> Significant arthritis involving all three compartments of the knee but occasionally may be indicated with only unicompartmental or bicompartmental involvement
Old age> b/c tkr has a finite expected survival that is adversely affected by activity level, it generaly is indicated in olger patients with more sedentary life styles. It is preferable that pts undergoing TKA have a remaining life expectancy of b/w 20 and 30 years so that the need for repeat arthroplasty for a failed TKA will be minimal . Young pts> tka may be indicated in a young age group but the pt must understand the limitations of the procedure, be willing to modify his or her life style to prolong the life of the prosthesis and be willing to risk the loer success rate in a revision arthroplasty. Deformity> deformity can become the principle indication for arthroplasty in pts with moderate arthritis and variable levels of pain when the progression of deformity begins to threaten the expected outcome of an anticipated arthroplasty. Intervening before this degree of deformity is present allows the use of a prosthesis that has a more favorable expected survival.
Remember that TKR surgery is elective it is not an emergency so the patientâs condition should be optimized before embarking on surgery. A detailed medical history should be obtained to prevent potential complications that can be life threatening or limb threatening. b/c most pts undergoing TKR are elderly, comorbid diseases must be considered. Examination> end stage arthritis may be associated with flexion contractures, varus or valgus angulations. All of these mal alignments must be taken into consideration when planning for TKR. Rule out and evaluate for potential serious vascular disease in the lower extremity. assessment of the skin is also important in TKR
The mechanical axis of the lower limb is an imaginary line through which the weight of the body passes. It runs from the center of the hip to the center of the ankle through the middle of the knee. This is altered in the presence of deformity and must be reconstituted at surgery, which protects the prosthesis from eccentric loading and early failure
Post operative physical therapy and rehabilitation greatly influence the outcome of TKR. ROM exercises are performed post operatively with or with out the assistance of CPM. CPM assist in obtaining knee flexion more quickly and thus decreasing the hospital stay.
Various studies shows varying results but most of them have 95% survival rate at 15 years