1. Total Knee Replacement
Dr. Twinkle Dabholkar (PT)
MPTh. (Musculoskeletal Conditions)

2. Indications for Surgery
Severe joint pain with WB or movements that comprises function
Extensive destruction of the articular cartilage of the knee following OA, RA, Post traumatic arthritis etc.
Gross instability or limitation of ROM
Marked deformity i.e. genu varum or valgum
Avascular Necrosis
Failure of conservative Rx or previous surgery.

3. Joint destruction

4. Indications for TKR - Malalignment

5. Operative Incision

7. Components of prosthetic replacement

8. How Is The Knee Replaced?
An incision approximately eight inches in length is made on the front of the knee.
The surgery involves exposure of the front of the knee, with detachment of part of the quadriceps muscle (vastus medialis) from the patella. The patella is displaced to one side of the joint allowing exposure of the distal end of the femur and the proximal end of the tibia.
The ends of these bones are then accurately cut to shape using cutting guides oriented to the long axis of the bones.
The cartilages and the anterior cruciate ligament are removed; the posterior cruciate ligament may also be removed but the tibial and fibular collateral ligaments are preserved.

9. Technique
Metal components are then impacted onto the bone or fixed using polymethylmethacrylate (PMMA) cement.
A round ended implant is used for the femur, mimicking the natural shape of the bone.
On the tibia the component is flat, although it often has a stem which goes down inside the bone for further stability. A flattened or slightly dished high density polyethylene surface is then inserted onto the tibial component so that the weight is transferred metal to plastic not metal to metal.
During the operation any deformities must be corrected, and the ligaments balanced so that the knee has a good range of movement and is stable. In some cases the articular surface of the patella is also removed and replaced by a polyethylene button cemented to the posterior surface of the patella. In other cases, the patella is replaced unaltered.

10. Technique
The upper end of the leg bone (tibia) is replaced with a plastic and metal implant with cement and or screws.
The back of the kneecap (patella) is also resurfaced with an all-plastic implant.

12. How Is The Artificial Implant Fixed To Bone?
Options available that hold the knee replacement into position:
Cemented procedure
Non – cemented procedure
Hybrid Fixation procedure
With a cemented procedure the components of the implant are fixed to the bone with a grout-like cement known as polymethyl-methacrylate. This cement allows the implants to perfectly fit to the irregularities of the bone.
Advantage - immediately stable and one can walk fully bearing weight immediately following surgery. Very reliable procedure with approximately 90 to 95 percent expected to enjoy pain-free activities for at least ten years beyond surgery.
Disadvantages - are that if it should become loose, some bone may be ground away by the loosened cement potentially making revision more difficult.

13. Non-Cemented
In a non-cemented procedure, components of the implant have a roughened porous surface designed to allow bone to grow into it, eliminating the need for cement.
The implants are "press fit" against the bony surfaces that are precisely cut through the use of multiple cutting jigs. Faultless positioning is necessary for bony attachment to occur with initial fixation by metal pegs and screws of the implant to bone. Since this implant relies on the bone to hold it in place, this procedure requires good bone to be successful
One potentially positive aspect is that if this implant should become loose, less bone loss may occur due to the lack of the irritant cement.
After surgery the individual with this type of implant is usually instructed to be toe-touch only until a follow-up x-ray usually done by the fifth or sixth week after surgery. The weight-bearing status following non-cemented knee replacement will be determined by the surgeon.

14. Hybrid fixation
Occasionally a hybrid fixation is used which consists of a combination of the cemented and non-cemented technique. In this method the femoral component is non-cemented and the tibia component is cemented.
At present, cemented knee replacements are most commonly used, representing 90% of knee replacement surgery. Non-cemented replacements are much less common, as are hybrid replacements.

15. Different Types Of Knee Replacements
Broadly speaking, there are four basic categories of knee replacements depending on the degree of mechanical stability provided by the design of the artificial knee:
Non-constrained
Semi-constrained
Constrained or hinged
Unicondylar

17. Different Types Of Knee Replacements
The highly successful non-constrained implant is the most common type of artificial knee. It is termed non-constrained because the artificial components inserted into the knee are not linked to each other and have no stability built into the system. It relies on the person's own ligaments and muscles for stability.
The semi-constrained implant is a device that provides increasing stability for the knee. This type of artificial knee has some stability built into it. It is used if the surgeon needs to remove cruciate ligaments or if the surgeon feels the new knee will be more stable with this type of implant.

18. Different Types Of Knee Replacements
Constraint or hinged variety implants are rarely used as a first choice of surgical options. In this case, the two components of the knee joint are linked together with a hinged mechanism.
- Used when the knee is highly unstable and the person's ligaments will not be able to support the other type of knee replacements. It is useful in the treatment of severely damaged knees particularly in very elderly people undergoing a revision replacement procedure. The disadvantage of this type of knee joint is that it is not expected to last as long as the other types.
A Unicondylar knee replacement replaces only half of the knee joint. It is performed if the damage is limited to one side of the joint only with the remaining part of the knee joint being relatively spared.

19. Risks and Complications
The most serious complication is Infection of the joint, which occurs in <1% of patients.
Deep Vein Thrombosis occurs in up to 15% of patients, and is symptomatic in 2-3%.
Nerve injuries occur in 1-2% of patients.
Persistent pain or stiffness occurs in 8-23% of patients.
Prosthesis failure occurs in approximately 2% of patients at 5 years. (including Osteolysis & loosening)

20. Complications
A complication that can cause the artificial components to loosen or damage the bone is called osteolysis meaning "breakdown of bone".
This may result over the years from tiny particles of worn-out plastic or cement that may potentially migrate into the bone and cause localized damage to the bone.
This condition may also result in the need for a total knee revision. That is another reason to have a yearly x-ray evaluation

21. Prosthetic infections
Relatively rare
Most challenging complications.
A detailed clinical history and physical examination remain the most reliable tool to recognize infection.
In some cases the classic signs of fever, chills, painful joint, and a draining sinus may be present, and diagnostic studies are simply done to confirm the diagnosis.
In reality though, most patients do not present with those clinical signs, and in fact the clinical presentation may overlap with other complications such as aseptic loosening.
In those cases diagnostic tests can be useful in confirming or excluding infection.

22. Choice of Treatment Rx depends on the type of prosthetic infection.
Positive intraoperative cultures: Antibiotic therapy alone.
Early post-operative infections: debridement, antibiotics, and retention of prosthesis.
Late chronic: delayed exchange arthroplasty. Surgical débridement and parenteral antibiotics alone in this group has limited success, and standard of care involves exchange arthroplasty.
Acute hematogenous infections: debridement, antibiotic therapy, retention of prosthesis.

23. Exercises
Standard exercises that are used for early postoperative knee replacement include:
Quadriceps setting
Terminal knee extension
Heel slides
Straight leg raising
Pillow squeezes

24. Maximum Protection Phase 1 to 2 weeks
Pain control
Ankle pumps, Chest care
Compressive wraps
Gain ROM – 0 to 90 degrees in 1st 2 weeks, CPM, Active assisted & active ROM exs, Patellar glides, Heel slides in supine & Towel extensions
Flexibility program – Hams, TA & ITB.
Muscle setting quads, hams and hip adductors
NMES

25. Moderate & Minimum Protection Phase (weeks 3 to 6)
ROM – 0 to 115 degrees
Control swelling
CKC strengthening - Minisquats
Resisted SLRs, Multiple angle isometrics
LE flexibility program, Patellar glides
Stationary bicycle
Progression to FWB (except with non-cemented)
Proprioceptive exercises.
Swimming, cycling or walking

26. Return to activity Phase beyond week 6
Develop maintenance program
Educate patient on joint protection
Protected aerobics.
Exs specific to functional tasks

27. THANK YOU