Traditionally, patients who had knee replacements stayed in the hospital for a week
or more. However, majority of the patients probably feel better and recover well
in their home environment rather than staying in a hospital bed unnecessarily. Health
economics has also focused the attention of hospitals, surgeons and rehabilitation
teams to develop strategies to safely discharge the patients early.
Proactive management of various aspects of the “patient’s journey” has been shown
to make safe early discharge achievable in majority of patients and some studies
have also shown that leads to faster recovery of function. Some of the factors include
patient education, accelerated rehabilitation techniques and minimally invasive surgery.
Mr.Ganapathi firmly believes in facilitating early functional recovery and adopts
the various techniques.
Accelerated rehabilitation (rapid recovery): The two major factors with this technique
is early physiotherapy and adequate pain management with a combination of analgesics
as well as local infiltration techniques. It has been shown that adopting multi-modal
analgesic techniques decreases the amount of narcotic pain killers needed by the
patients (opioid analgesics which can lead to drowsiness and hence delay rehabilitation).
Minimally invasive surgery (MIS TKR): This essentially involves modification of the
surgical techniques to minimise the incision through the quadriceps tendon (muscle
sparing approach). Traditional incision (medial para-patellar approach) for the knee
replacements are done with a cut almost through the middle of the quadriceps tendon
(the thigh muscle which attaches to the knee cap). Although all the incisions through
the tendon eventually heal, there is to certain extent some delay in the recovery
till the tendon heals. Hence modifications of the techniques have been developed
which spares the quadriceps tendon completely (subvastus approach) or spares majority
of the quadriceps tendon (midvastus approach).
Recent studies have shown that these techniques allow early functional recovery following
total knee replacements. However, these techniques are technically more difficult
and not all patients may be suitable for these techniques. In addition, some studies
have suggested that there may be higher incidence of variations in the placement
of the implants. But other studies have shown that using computer guidance, minimally
invasive surgery could be performed accurately.
Mr. Ganapathi routinely uses computer guidance for knee replacements and in addition
adopts minimally invasive technique (mid-vastus approach) in suitable patients along
with accelerated rehabilitation (rapid recovery).
The following are some relevant selected scientific references:
1. A comparison of early clinical outcome in computer assisted surgery and conventional
technique in minimally invasive total knee arthroplasty.
J Med Assoc Thai. 2009 Dec;92 Suppl 6:S91-6.
Chaiyakit P, Hongku N, Meknavin S.
Abstract- OBJECTIVE: To compare the clinical outcomes of minimally invasive total
knee arthroplasty (MIS TKA) with and without computer assisted surgery (CAS). MATERIAL
AND METHOD: From September 2007 to February 2008, 64 patients (70 knees) underwent
MIS TKA were included. Clinical data such as operative time, pain score, total blood
loss and Radiographic data were recorded and compared. RESULTS: There were no significant
different in clinical outcome of both groups but range of motion of MIS group was
better than CAS group. However, the percentage of outlier of bone cut in CAS group
was 6.5% on both femur and tibia while percentage of outlier in MIS group was 16.6%
on femur and 25% on tibia. DISCUSSION: Combining CAS with MIS TKA showed improvement
of accuracy in coronal bone cut without increase of operative time or complications.
The difference of ROM may be due to different prosthesis design in each group.
2. Minimally invasive subvastus approach: improving the results of total knee arthroplasty:
a prospective, randomized trial.
Clin Orthop Relat Res. 2010 May;468(5):1200-8.
Varela-Egocheaga JR, Suárez-Suárez MA, Fernández-Villán M, González-Sastre V, Varela-Gómez
JR, Rodríguez-Merchán C.
Abstract - BACKGROUND: Minimally invasive knee arthroplasty seeks to diminish the
problems of traditional extensile exposures aiming for more rapid rehabilitation
of patients after surgery. QUESTIONS/PURPOSES: To determine if the subvastus approach
results in less perioperative pain and blood loss, shorter hospital stay, and improved
function at both early and long-term followup. METHODS: One hundred patients were
enrolled in a prospective, randomized trial. Fifty were operated on using a minimally
invasive subvastus approach and the other 50 by a conventional, peripatellar approach.
Minimum followup was 3 years. A repeated-measures analysis of variance was used to
compare the Knee Society score and range of motion during followup. RESULTS: The
minimally invasive approach resulted in greater perioperative bleeding but no increase
in transfusions. No differences were found in postoperative pain between groups nor
did hospital stay show any differences. The range of motion on the third day after
surgery was greater in the minimally invasive group. No differences were found in
surgical time, femoral or tibial component orientation or outliers, or complication
rates. Both Knee Society score and range of motion were superior using the minimally
invasive subvastus approach during followup out to 36 months. CONCLUSIONS: The minimally
invasive subvastus approach can result in improved long-term Knee Society scores
and range of motion of total knee arthroplasty without increased risk of component
malalignment, surgical time, or complication rate. LEVEL OF EVIDENCE: Level I, therapeutic
3. A comparison of subvastus and midvastus approaches in minimally invasive total
J Bone Joint Surg Am. 2010 Mar;92(3):575-82.
Bonutti PM, Zywiel MG, Ulrich SD, Stroh DA, Seyler TM, Mont MA.
Abstract- BACKGROUND: The mini-subvastus and the mini-midvastus approaches are among
the most common alternatives to the medial parapatellar approach for total knee arthroplasty.
The purpose of this study was to compare the early clinical outcomes of these two
approaches. METHODS: In this prospective, randomized study of fifty-one patients
who underwent bilateral total knee arthroplasty, the mini-subvastus approach was
used in one knee and the mini-midvastus approach, in the contralateral knee. There
were forty-two women and nine men who had a mean age of seventy years at the time
of the index arthroplasties, and they were followed for two years postoperatively.
Clinical outcome was assessed and compared with use of the Knee Society pain and
function scores, the straight-leg-raising test, range of motion, and isokinetic strength
testing. Operating time and blood loss for each approach were also compared. In addition,
patients were surveyed concerning which knee they preferred. RESULTS: Comparisons
of postoperative Knee Society scores between both approaches at the time of the two-year
follow-up did not yield a significant difference in outcome. Isokinetic strength
testing at twelve weeks postoperatively revealed no significant differences in muscle
strength, with a mean extensor peak torque-to-body weight ratio of 0.14 Nm/kg for
both groups. No significant difference was found with respect to total blood loss,
straight-leg-raising test, range of motion, or patient preference. There was no clinically
relevant difference in operative times between the two approaches. CONCLUSIONS: The
minimally invasive subvastus and midvastus approaches for total knee arthroplasty
were both associated with excellent short-term clinical results. Some surgeons believe
that the subvastus approach completely avoids damage to the quadriceps mechanism
and therefore would be associated with improved muscle function. This prospective
series did not identify a substantive difference between the two approaches. We believe
that the decision between these surgical approaches should be based on surgeon preference
4. Minimally invasive computer-navigated total knee arthroplasty.
Orthop Clin North Am. 2009 Oct;40(4):537-63, x.
Biasca N, Schneider TO, Bungartz M.
Abstract -Modern computerized knee navigation systems aid surgeons both in the conventional
and in the minimally invasive approach to optimize mechanical and rotational alignments
of the components in all three planes to avoid any malrotation and/or any errors
in coronal, sagittal, and axial alignments. The advantages of minimally invasive
total knee arthroplasty can be achieved without loss of accuracy. There is increasing
evidence of a positive correlation between accurate mechanical alignment after total
knee arthroplasty and functional as well as quality-of-life patient outcomes.
5. Minimally invasive total knee arthroplasty using the contralateral knee as a control
group: a case-control study.
Int Orthop. 2010 Apr;34(4):491-5.
Bonutti PM, Zywiel MG, Seyler TM, Lee SY, McGrath MS, Marker DR, Mont MA.
Abstract -The primary purpose of this study was to compare clinical and functional
results of bilateral total knee arthroplasties in which a conventional total knee
replacement was initially performed on one knee and a minimally invasive total knee
replacement was later performed on the contralateral side. Operative factors, clinical
and radiographic outcomes, and quadriceps muscle strength were evaluated in twenty-five
patients (50 total knee arthroplasties). Twenty-one of the 25 patients preferred
the minimally invasive approach. Knee society objective scores and range-of-motion
were significantly greater in the minimally invasive group. Isokinetic testing demonstrated
statistically improved quadriceps muscle strength in the minimally invasive technique
group compared to the standard approach at both 12 weeks and one year postoperatively.
Radiographic analysis did not reveal differences in alignment variables between the
two approaches. The results of this study suggest that minimally invasive total knee
arthroplasty offers superior short-term as well as possible long-term results.
Marking showing the traditional Medial para-patellar approach
Marking showing the comparison with mid-vastus approach
Green shaded area represents the extent of muscle sparing compared to traditional approach
Knee joint is exposed through the mid-vastus approach
After knee replacement - majority of the quadriceps muscle is still intact
After closure - majority of the extensor mechanism is intact