Total Knee Replacement

Total knee replacement (TKR) is one of the most successful medical innovations developed in the last century, can substantially improve patients’ quality of life, and has been well validated.

NICE guidance suggests “referral for joint replacement surgery should be considered for people with osteoarthritis  who experience joint symptoms (pain, stiffness and reduced function) that have a substantial impact on their quality of life and are refractory to non-surgical treatment. Referral should be made before there is prolonged and established functional limitation and severe pain”.

Younger age should not preclude joint replacement surgery.
The success of knee replacement surgery has now equalled, and perhaps even surpassed, that of hip replacement, with 90-95 per cent success rate at 10 to 15 years.

 

Implant type

Many factors determine surgeon preference for an individual implant. These include age, weight, level of activity, health, cost of prosthesis, their trainers, consultant colleagues, the desire to improve their own results and service delivery of the manufacturers.

The decision to use a particular type of knee implant will depend on a number of factors, which include – patient factors, surgeon decision etc.

There are, broadly speaking Three types of knee replacement:

1.      Unicondylar  knee replacement (UKR)

  • Occasionally, if only one part of the knee joint is severely worn, then uni-compartmental or patello femoral replacement surgery is recommended rather than TKR.
  • While unicompartmental knee arthroplasty offers both the possibility of a more rapid recovery as well as a conservative approach to the treatment of knee arthritis, UKR’s indications are very limited.
  • Patients that may not be eligible for a UKR include patients that have an inflammatory arthritis;have major deformities that can affect the knee mechanical axis;are obese;lost a severe amount of bone from the tibia; or have severe tibial deformities;have recurring subluxation of the knee joint; have untreated damage to the patellofemoral joint;have untreated damage to the opposite compartment or the same side of the knee not being replaced by a device; and/or have instability of the knee ligaments such that the postoperative stability the UKR would be compromised.

2.      Unconstrained bicompartmental knee replacement

  • This is the most common form of TKR. The lower part of the replacement knee joint is comprised of a flat metal plate and stem that implants in the tibial bone. This tibial tray can be either cobalt chrome alloy or titanium alloy.  It can be fixed by either cement or bone “ingrowth”.
  • Next, a polyethylene insert is clipped into the tibial tray to serve as the new knee bearing surface.  The upper part of the replacement knee joint consists of a contoured metal shield that fits around the lower end of the thigh bone (femur).
  • The inner surface can be fixed to the cut bone surfaces by the surgeon’s choice of bone ingrowth or bone cement.  The outer surface of the contoured metal shield is shaped to allow the patella to slide up and down in its groove. The surgeon may choose to retain the patella or re-surface it.  In this case a polyethylene button will be cemented in place.

 3.      Posterior cruciate ligament (PCL) – retaining or substituting

  • In total knee replacement surgery, the PCL can be kept or removed; and this choice depends on the condition of the PCL, the type of knee implant, or the type of surgery the surgeon likes to do.  Each of these designs has advantages and disadvantages.
  • Surgeon preference depends on his or her training and the clinical situation. PCL-substituting knees (also called posterior stabilised knees) have a raised sloping surface or a polyethylene post that compensates for the missing PCL to give the knee more stability. 

Knee replacements may be “cemented” or “cementless”, depending on the type of fixation used to hold the implant in place.

The majority of knee replacements are generally cemented into place.

Constrained bicompartmental knee replacement

These prostheses are used principally in revision cases, or when considerable bone loss (bone tumours) or collateral ligament damage is present. The joint works like a hinge and is much more prone to loosening.

Complications

  •          Ninety per cent of patients have excellent or good outcomes following TKR.
  •          Infection (one-two per cent)
  •          Venous thromboembolism
  •          Others include:
    • Neurovascular Injury (one per cent).
    • Fracture (< one per cent).
    • Persistent pain or stiffness  (five-10 per cent)
  • Prosthesis failure (90 per cent survivorship @ 10-15 years)

Recent advantages-

Minimally invasive surgery

  • Minimally invasive surgery was developed to reduce the size of the incision and limit damage to underlying structures. However, while these improvements have a real theoretical advantage, one must be cautious in its widespread use. At three months postoperatively there is no difference in the comfort and function of patients having conventional surgery and those having an MIS procedure.
  • Also, with limited access there is an increased risk of implant malposition that can affect the long term-success of the replacement. It is clear that the length of the skin incision has very little effect on postoperative recovery or blood loss after TKR. The use of smaller incisions may actually compromise wound-healing and can increase operative time, which may increase the probability of contamination. My personal belief is to do the surgery as safely and as effectively as possible through the smallest incision possible.

Navigation and robotics in TKR

Patient specific instrumentation in TKR – Customized or patient specific jigs are the latest that TKA technology has to offer. Herein, the patients’ preoperative CT scan is done. The CT scan is assessed by the computer which draws a pre-operative plan – MUCH BEFORE THE ACTUAL SURGERY. This helps the surgeon to assess the situation encountered during the surgery and helps significantly in preoperative planning.

This preoperative CT scan is used to manufacture jigs which are used intra-operatively and are specific for only that particular patient.

The advantages of using patient specific instruments is that it leads to faster recovery, decreased blood loss, improved alignment, decreased surgical time and improved rehabilitation.

   

Perioperative management

  • The evolution of perioperative pain management and physical therapy. The multimodal pain protocol includes preemptive analgesia and an injection at the time surgery which consists of a combination of ropivacaine, morphine, epinephrine and ketorolac.
  • The percentage of patients who are able to perform a straight leg raise on the first postoperative day is significantly higher in the multimodal pain protocol group than in the standard protocol group. Less narcotic consumption and fewer side effects as well as improved early functional recovery are commonplace.

TKR is successful in the majority of patients, but patients’ expectations need to be managed appropriately. Future developments, such as navigation-guided surgery, better oral anticoagulants, enhanced kinematics, and wear-resistant bearing surfaces with better fixation, promise a consistent evolution for the total knee replacement procedure.

OUR PROTOCOL AND ADVANCES WE USE –

  • Patient specific instruments – We have had excellent results with the use of this technology and we have had many international publications pertaining to this topic in journals of repute.
  1. VR, Vijay Vipul, VA. Patient-specific instrumentation does not shorten surgical time: a prospective, randomized trial. The Journal of Arthroplasty. Volume 29, Issue 7, July 2014, Page 1508.
  2. VR, Vijay Vipul. Patient-specific instruments in total knee arthroplasty.  International Orthopaedics (SICOT) 2014. 38:1123–1124.
  3. VR, Vijay Vipul, BV. Patient specific instruments for primary Total Knee Arthroplasty: a new concept. Apollo Medicine. (2014) DOI: http://dx.doi.org/10.1016/j.apme.2014.11.008
  4. Vaishya R, Vijay Vipul, AAK. Functional outcome and quality of life after Patient-Specific Instrumentation (PSI) in Total Knee Arthroplasty (TKA): our concerns. J Arthroplasty. April 2016; 31 (4), 924.
  5. BV, VR, Vijay Vipul. Comparative Study Of Outcomes Of Patient Specific Instruments And Conventional Jigs In Primary Total Knee Arthroplasty. J Medical Thesis. 2016; 4(1):43-47.16
  6. VR, Vijay Vipul, AAK. A Systematic Literature Review of Three Modalities in Technologically Assisted TKA: Concerns and comments. Advances in Orthopedics. 2016, Article ID 6539878, 2 pages; http://dx.doi.org/10.1155/2016/6539878.
  7. VR, Vijay Vipul, BV. CT based ‘Patient Specific Blocks’ improve postoperative mechanical alignment in primary Total Knee Arthroplasty. World J Orthop (in press).
  8. VR, Vijay Vipul, AAK. Total knee arthroplasty using patient-specific blocks after prior femoral fracture without hardware removal. Ind J Orthop (under review)
  • USE OF LOCAL INFILTRATIVE ANALGESIA – The use of this form of multimodal analgesia helps in better postoperative pain relief. This technique of multimodal analgesia has been accepted and published in journals of international reputation.
  1. Vijay Vipul, VR, WAM. Local infiltrative analgesia reduces post op pain and hospital stay in total knee replacement. J Clin Ortho Trauma 2015, 6:66.
  2. Vijay Vipul, VR. Local infiltration analgesia v/s standard analgesia in TKA: some concerns. J Orthop Surg (Hong Kong). Dec 2015, 23 (3); 406-407.
  3. VR, WA, Vijay Vipul. Local Infiltration Analgesia is effective in pain control and reduction in length of hospital stay in primary Total Knee Arthroplasty: A Randomized Double-Blinded Controlled Study.  Acta Orthop Belgica. 2015, 81(4);720-29.
  • AGE IS NO MORE A CRITERION FOR TOTAL KNEE REPLACEMENT – Age of the patient is no more a criterion for total knee replacement. In selected individuals who are even above the age of 70 years, both knee replacements can be carried out in the same sitting. Our experience has been shared at international stage and in renowned journals.
  1. VR, Vijay Vipul, KCMK, VA. How old is an old for a Simultaneous Bilateral Total Knee Arthroplasty? J Am Geriatr Soc. OCT 2014–VOL. 62,  2011-2012. doi: 10.1111/jgs.13032.
  2. VR, Vijay Vipul. Simultaneous Bilateral Total Knee Arthroplasty in Elderly Greater than 70 Years Old.  AAOS 2016, Orlando.
  3. Vijay Vipul, VR. Simultaneous Bilateral Knee Arthroplasty in Octogenarians: Can It Be Safe and Effective? J Arthroplasty. 2014. DOI: 10.1016/j.arth.2014.04.038
  4. VR, Vijay Vipul. Simultaneous bilateral knee arthroplasty in octogenarian: can it be safe and effective. J Arthroplasty. Volume 29, Issue 9, September 2014, Pages 1877-1878. doi: 10.1016/j.arth.2014.04.038.
  5. VR, Vijay Vipul. Can Total Knee Arthroplasty be safely performed among nonagenarians? An evaluation of morbidity and mortality within a Total Joint Replacement registry. J Arthroplasty. January 2015 Volume 30, Issue 1, Pages 156–157. doi: 10.1016/j.arth.2014.09.017.