KNEE REPLACEMENT SURGERY

When large areas of the knee lose their precious protective coat, the articular cartilage, the load bearing function of the knee is severely compromised. Bony surfaces rubbing against each other cause pain, occasional swelling and a progressive deformity. The shock absorbers (menisci) that separate the two surfaces gradually degenerate and develop tears. Occasionally such tears cause symptoms of instability (locking, giving away or recurrent swelling).

Early stages of arthritis can be dealt with medicines and exercises. Some patients benefit from injections in the knee – either steroids or viscosupplements. Subjective instability can be dealt with very effectively by means of a small telescopic procedure whereby the torn bit of shock absorber and all loose debris is removed – Arthroscopic Debridement. Early deformity with arthritis limited to one half of the knee can be very successfully dealt with by Joint Realignment Procedures. However, large areas of cartilage loss require replacement surgery.

Replacement Surgery has seen major advances through its evolution over the last four decades. These developments are broadly in two spheres:

  • Implant Design and Fixation
  • Surgical Techniques

IMPLANT DESIGNS

  • There are several different implant designs that cater to varied stages of arthritis, knee ligament integrity, cultural needs, and age groups.
  • If only one half of the knee is affected we replace just this portion of the knee – a Unicompartmental Knee Replacement. This replacement procedure preserves an important ligament at the front of the knee (the ACL, otherwise destroyed in a total knee replacement) and thus restores normal knee biomechanics much better – it feels more natural
  • Another recent variant of replacing a selected portion of the knee is the Patellofemoral Replacement which simply replaces the back of the knee cap and its adjoining area.
  • The natural knee besides bending backwards can also normally twist (rotate) in small degrees. This twist is important in certain postures of the knee. Recognition of this fact led to the development of knees with a Rotating Platform. Several knee designs now incorporate this feature.
  • A better understanding of the complex mechanics of motion of the knee has led to the inception of the High Flex/Gender Knee. Such knees by virtue of their design conform better during extreme ranges of knee motion and thus provide a "better bend". This feature is especially useful in the Asian, African and Middle East population where kneeling, squatting and cross legged sitting are a way of life
  • Retaining or substituting the function of an important ligament at the back of the knee (the posterior cruciate {PCL} depends on the functional integrity of this ligament prior to surgery. Thus knee replacements could be either PCL Retaining or PCL Substituting.
  • Knees with severe deformities or failed knee replacement patients require standard design modifications/additions or at times Custom Made Prostheses.
  • The Satya Trauma & Maternity Center Team is well versed at managing such patients with differing needs.

SURGICAL TECHNIQUE

  • Advances in Surgical Techniques have primarily led us to
  • Reduce the size of our incisions (Minimally Invasive Surgery, MIS) thereby ensuring less pain and faster recovery. Conduct the surgery with robotic precision using the computer which ensures longer lasting knees with a more natural feel (Computer Assisted Navigation Systems, CAS)
  • Well trained Specialist Knee Surgeons such as Dr Amit Nath Misra (as against General Orthopaedic Surgeons also performing replacement surgery) are trained in such techniques.

THE CUSTOM BUILT KNEE REPLACEMENT

  • It is now possible for us to implant a knee which exactly fits the patient's size. Until now, there were 5-6 standard sizes available. We used to fit the patient to one of these sizes.
  • The advent of this recent technology enables us to better replicate the patient's natural knee. Preoperative MRI scans are taken. Measurements are taken off this scan. A knee is built precisely replicating these dimensions.
  • The advantages of such knees are yet to be studied over a period of time. However, they might hold promise for the future by feeling more natural and/or lasting longer.