A prospective comparative study of the midvastus and medial parapatellar approaches for total knee arthroplasty in the early postoperative period
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The commonest surgical approach for total knee arthroplasty is medial parapatellar approach. This involves splitting the quadriceps tendon and disrupts the extensor mechanism and this may potentially weaken it. The midvastus approach involves splitting the vastus medialis muscle instead of entering the quadriceps tendon; therefore, minimising interruption of the extensor mechanism without compromising the exposure of the knee.
To compare the clinical parameters associated with medial parapatellar and midvastus approaches for total knee arthroplasty in the early postoperative period.
Methods and results
We present a prospective observational study of 77 patients undergoing primary total knee arthroplasty using medial parapatellar or midvastus approach (37 midvastus, 40 medial parapatellar). The prosthetic design and physical therapy intervention were standardized in all the patients. The Oxford Knee Score, pain scale, knee flexion, unassisted straight leg raise, standing and walking were compared at 3rd, 5th and 7th day postoperatively. These parameters were checked again at 6 weeks and at 3 months following the operation. The patients and physiotherapist were blinded to the type of approach used. The mean age was 71 years (range 48–88). There were 44 women and 33 men. The mean duration to achieve straight leg raise for the midvastus group was 3.5 days (SD ±1.2) and for the medial parapatellar approach group was 5 days (SD ±1.3) The mean hospital stay for the midvastus group was 5 days (SD ±2.5) and for the medial parapatellar group was 6.5 days (SD ±2.6). The difference between the two groups was statistically significant (P = 0.003) There was a statistically significant difference in duration of hospital stay, straight leg raise and rising from a chair unassisted, all in favour of midvastus approach. There was no statistically significant difference in Oxford Knee Scores, pain scale and range of motion.
The study shows that total knee arthroplasty performed through the midvastus approach resulted in earlier unassisted straight leg raise and ambulation; therefore, shorter hospital stay as compared to medial parapatellar approach. This is of benefit to the patients in the healthcare system due to faster rehabilitation and shorter hospital stay.
KeywordsTotal knee arthroplasty Midvastus approach Medial parapatellar approach
Conflict of interest statement
I confirm that no benefits or funds were received in support of this study.