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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).

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

Green shaded area represents the extent of muscle sparing compared to traditional approach

Knee joint is exposed through the mid-vastus approach

1. Example of a patient who had a computer guided MIS TKR through mid-vastus approach, multimodal analgesia and accelerated rehabilitation (video showing active knee movement at 2 hours post surgery)
2. Example of a patient (age – almost 80 years) who had a Computer Guided Total Knee Replacement, multi-modal analgesia and  accelerated rehabilitation (video showing  patient mobilising with a walker frame at 7 hours post surgery)

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 study.

3. A comparison of subvastus and midvastus approaches in minimally invasive total knee arthroplasty.

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 and experience.

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.

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