Minimally Invasive Total Knee Replacement Surgery
By: Aya C. Chow
The
Minimally-Invasive Total Knee Replacement (MIS-TKA) and the Conventional Total
Knee Replacement Surgery are not two different surgeries, but rather two
different techniques with the same goal in mind. That goal is to provide
patients with a knee implant to replace the natural knee too damaged for
everyday activities.
Both techniques require an incision be made over the
kneecap to execute the procedure. The
MIS approach generally requires a 3-inch incision while the conventional
approach requires an incision generally ranging from 6 to 8-inches in
length. In the case of the conventional
incision, the length of it is proportionate to the patient’s size, which allows
the surgeon clear visibility and a sufficient surgical field to perform the
operation.
The MIS-TKA approach usually
requires the use of tiny tools and fluoro-optic technology to allow visibility
and proper placement of the implant, while the conventional TKA approach does
not make use of them since the larger incision does not require them.
Currently, proven prosthetic designs with published results are being
used for both techniques, but plans to adapt prosthetics and surgical tools
specifically for the MIS-TKA technique is under way to facilitate implantation
and aid in proper placement.
Similar to the surgeons’ experience
of this procedure, the patients’ experience can also vary greatly between the
conventional and MIS approach. With the
conventional method, the patient can experience an average of one to two pints
of blood loss, soft tissue trauma around the incision, a hospital stay of 4
days, a recovery period of about six weeks and a scar equal to the incision of
about 6 to 8 inches in length. In
comparison, because the MIS approaches require a smaller incision, surgeons in
the MIS-TKA early trials saw faster recovery times, less blood loss, shorter hospital stays, and increased range
of motion “than a comparable group of patients who underwent the standard
arthrotomy technique.”1
At the annual American Associate of
Orthopaedic Surgeons (AAOS) meeting held this past February, a group of
surgeons who just completed early trials for the MIS-TKA study indicated
promising results for patients who underwent the new procedure. Alfred J. Tria,
MD and Thomas Coon, MD, coauthors of the study entitled “Minimal Incision TKA:
The Future of Knee Arthroplasty.” are amongst a very limited number of surgeons
who are performing this new procedure.
It must be kept in mind the
difference in maturity in the two techniques however. The conventional
approach, with minor alterations to surgical technique, has been done for almost
forty years. There is ample evidence
supporting the safety and effectiveness of this method by studies conducted by
top orthopedists and published in respected orthopedic journals. This is not
the case with the MIS-TKA approach, as it has just started on its road to
establishing itself.
“In
terms of results, the follow-up of this [MIS-TKA] study is short term and can
only indicate trends at best. Long-term research on patient outcomes will need
to be conducted and compared to existing data on well-established”2
knee replacements.
The MIS-TKA
procedure is not widely available at this current time.