Bionic Knee

For patients with disabling knee osteoarthritis, total knee arthroplasty (TKA), is widely considered a successful management option. Following TKA, most patients can expect long term reduction in pain and improvements in quality of life. Patients between 72% and 86% report that they are satisfied with their postoperative outcome.

In a recent study of more than 60.000 revision TKA in the USA, infection was identified as the leading cause of revision (25,2%), followed by mechanical loosening (16,1%) and implant failure/breakage (9,6%).A mete-analysis found that as 30 of deviation from mechanical alignment in the coronal plane significantly increased the risk of TKA failure.

Some of the most important recent improvements in Orthopaedic surgery  include manufacturing prosthetic implants covered by a biofilm and nano-detectors for quicker isolation of a prosthetic infection ( in phase of pre-clinical testing at the moment), manufacturing of prosthetic implants that can last almost for ever and surgical technique (M.I.S) with minimal invasive intervention.

We were one of the pioneers in Greece to produce the “M.I.S” TKA, the “Smart” TKA, the “Tailor-Made” and the “Robotic” Knee.

All the above are now part of the past in Orthopaedics, after the use of Bionic or Biomimetic TKA, which can be fully adapted to our knee joint and can act normally with full range of motion. It can mimic normal knee joint biomechanics and is actually bionic cause it is more powerful that our own bone.

The Bionic or Biomimetic knee is an evolutionary technology in prosthetic implants industry,that, through biomedical engineering, makes the new knee joint to act perfectly. It is fully supported by digital world.

Its “artificial intelligence” is well incorporated in recipient’s knee, improving biomechanics and range of motion in the affected knee.

The Bionic or Biomimetic Knee has it’s own characteristics such as:

  • Tailor-made prosthetic implants that mimic each patient’s bone morphology
  • Prosthetic implants that can last almost forever, produced with the aid of Vitamine E (very strong antioccidant)
  • Minimally Invasive Surgical Technique for minimal complications and
  • Computer-navigation or robotics for improvement of prosthetic implantation in the proper position for long-term follow-up.

The surgical procedure does not need an extended trauma. The surgeon does not need to sacrifice a lot of muscle bellies, or make a big trauma. Under this circumstances

  • The complication rates of infection is minimized
  • There is no blood loss
  • The patient is quickly mobilized post surgery
  • Can walk easily without external aid
  • There is actually no need for pain killer uptake.

The pain can be easily controlled with the use of simple pain killers and there is no need for NSAID’s uptake, with the use of specified Rapid Recovery Protocols. These protocols give the ability of patient’s discharge after the first day post operation.

The surgical procedure does not need an extended trauma. The surgeon does not need to sacrifice a lot of muscle bellies, or make a big trauma. Under this circumstances

  • The complication rates of infection is minimized
  • There is no blood loss
  • The patient is quickly mobilized post surgery
  • Can walk easily without external aid
  • There is actually no need for pain killer uptake.

The pain can be easily controlled with the use of simple pain killers and there is no need for NSAID’s uptake, with the use of specified Rapid Recovery Protocols. These protocols give the ability of patient’s discharge after the first day post operation.

Tailor-made prosthetic implants

One of the main characteristics of a Bionic or Biomimetic Knee is the custom-made prosthetic implants use. These implants are patient specific and can be produced in the laboratory under specific details through 3D-CT scan or MRI, so that they can match to patient’s bone anatomy.

Specific instrumentation and jigs can be also produced and bone osteotomies can be made easily.

In this way we can avoid extensive osteotomies and minimize the possible complication of a periprosthetic fracture, or having a bigger sized knee with subsequent less R.O.M and functionality in the other hand.

We need about 7-10 days in the lab in order to have the custom-made implants available.

In a very short time it is well-adapted and stops to be a foreign body.

Some of the main characteristics of the custom-made implants include:

  • They are composed of noble metals
  • They are very light
  • Match exactly to patient’s bone morphology
  • Can mimic a normal knee
  • It is compatible with human body

Prosthetic implants that can last almost forever 

The most important element in the Bionic or Biomimetic Knee is that the prosthetic part of implant (tibial insert) that replaces menisci and is actually the main cause for implant failure is now “biologic” as it contains  Vitamin E in his chemical bond that ensures maximum resistance in walking and long-term follow-up and minimizes the possibility of a revision procedure.

A specific technique is used in the lab in order to produce the new implant with the Vitamin inside and that can act as the most powerful antioxidant and protects the metallic parts of implants from acidosis.

New technology is a new class of prosthetic materials in surface total knee arthroplasty and it excels in all comparative studies with other prosthetic implants that we also use in the operating theatre, as combines real antioxidant stability, high mechanical strength and extremely low wear.

In fact it shows 86-87% less wear than the corresponding materials made by melting and compression.

MIMIMALLY INVASIVE TECHNIQUE (MIS)

Minimally invasive knee surgery is often presented as a technique limited to small incision in the skin. In reality, however, it concerns a technique designed to reduce the trauma, both in soft tissue and bone.

It is an evolution of the old 25-30 cm interstitial passageway used for classic knee replacement and usually does not exceed 5-7 cm long.

The goal of minimally invasive knee surgery is to reduce postoperative pain, minimize bleeding and blood transfusion, make hospital stay shorter, achieve immediate post-operative full range of motion, avoid high muscle atrophy, and return the patient’s daily activities in a shorter time.

The muscle that surrounds the anterior surface of the knee and encloses the patella is the quadriceps tendon.

Its main action on the knee is achieving extension of the knee joint. In the minimally invasive technique we try to avoid dividing the inner quadriceps from the rest of the muscle.

The maintenance of the medial broad muscle (VMO) in the midvastus or subvastus accesses, essentially maintains the extensive knee mechanism intact, resulting in immediate mobilization and painless restoration of walking ability of the patient.

Computer-navigation or robotics 

The implantation of materials is accomplished with the help of computers and Robotic Technology. Why do we use computers in Orthopedics?

IN ORDER TO INCREASE THE SURGERY’S PERCEPTION IN THE SURGICAL FIELD AND THE EXECUTION OF SURGICAL INTERVENTION.

Further goals:

  • Maximize accuracy of placement of prosthetic implants
  • Repeatability of surgery
  • Patient Personalized Surgery
  • Minimal invasiveness
  • Reduction of early failure of TKA

TYPES OF COMPUTER ASSISTED SURGERY (CAS) SYSTEMS

CAS systems are classified into three main categories :

  1. PASSIVE: the system assists the procedure under the direct control of the surgeon. For example CAS is used to position the cutting blocks in the exact desired position, but the surgeon uses conventional instruments to make the bone cuts. Navigation is part of this category.
  2. SEMIACTIVE: are controlled robotic tools where the system restricts a task within a predetermined frame. In other words it is an enforced controlled robot.
  3. ACTIVE : are robotic tools performing surgical tasks such as drilling or milling without the direct intervention of the surgeon.

DIFFERENT MODALITIES OF CAS SYSTEMS

  • Image-based modality: this modality consists of three-dimensional constructs created using images obtained from pre-operative Ct or MRI.
  • Image-free modality: this modality does not require any imaging. The patient’s anatomical landmarks are collected directly during surgery to create the patient specific model.

TYPES OF PASSIVE CAS

  • Tracker pins
  • Surface-mounded Navigation
  • Hand-held Navigation
  • Perseus
  • i-Assist
  • OrthAlign
  • Pressure Sensors

TYPES OF SEMIACTIVE & ACTIVE CAS (4 robotic platforms available)

  • ROBODOC
  • NAVIO
  • i-BLOCK
  • MAKO

ADVANTAGES OF CAS & ROBOTIC T.K.A

  • Patient specific surgical planning
  • Robotic assisted femoral and tibial osteotomies
  • Avoidance of thromboembolic complications, as we do not use intramedullary rods
  • Minimizing of peri-operative complications
  • Accuracy in prosthetic implantation- Improved leg alignment
  • Excellent leg functionality
  • Maintenance of proprioception
  • Minimally invasive surgical technique without extensive soft tissue damage
  • Quick mobilization (4-5 hours post surgery)
  • Minimal hospitalization ( 1-2 days)
  • Minimizing of pain killers
  • avoiding painful physiotherapy programs (only 1/10th patients need physiotherapy after surgery)
  • Quick return to day-to-day activities.
  1. 17% more complication rate compared to conventional TKA, due to
    • Pin tracker related problems (fractures, loosening)
    • Additional duration of the operation
    • Radiation associated with a pre-operative CT scan
  1. High start-up cost
  2. Long learning curve ( avoids most of surgeons or hospitals to use it)
  3. Lack of versatility intra-operatively, which can result in the abandonment of the robotic procedure and conversion to a conventional one.

Dr. Alevrogiannis can assess your condition and condition, either in his office or at the Metropolitan General.