A Retrospective Analysis of the Modified Intervastus Approach
TAKE-HOME POINTS
- The modified intervastus approach to the knee spares the quadriceps tendon and the vastus medialis muscle.
- The modified intervastus approach is an extensile approach.
- The modified intersvastus approach is a safe approach to the knee that can be used in total knee arthroplasty and leads to early straight-leg raise and a rapid recovery.
- The modified intervastus approach can be used on the majority of patients requiring a total knee replacement.
- The modified intervastus approach utilizes a unique closure that avoids soft tissue strangulation.
DISCUSSION
TKA is a successful procedure that restores knee function with pain relief in osteoarthritis patients. The SV approach for TKA has better outcomes in terms of the VAS, ROM, straight-leg raise with faster rehabilitation compared with the standard MP approach;8–12 however, it can be challenging and time-consuming when used in morbidly obese and muscular patients.3 The SV approach can also increase the risk of complications such as patellar tendon avulsion or medial collateral injury because of the difficulty in exposure specifically for knees with limited ROM.13 Here we introduce the MIV approach as an alternative to the SV approach, overcoming most of these difficulties.
With the prevalence of morbid obesity and the market demand for minimally invasive techniques, we believe the MIV approach represents a good approach for surgeons since it is easy to perform, does not require specialized instrumentation, and is a reproducible approach even on the most complex deformities. The minimal time added to ensure blunt elevation of the vastus medialis muscle and an anatomic repair of the underlying knee capsule and vastus medialis fascia to the medial edge of the quadriceps tendon allows restoration of the anatomy and a robust double-layered watertight seal closure with no strangulation of soft tissues. We believe this reproducible muscle- and tendon-sparing approach that allows gentle, soft tissue handling even in the most complex primary total knee cases may lead to less soft tissue swelling, and therefore, less postoperative pain resulting in an accelerated recovery.
The pain level in this group of patients was reduced after the MIV approach as indicated by the VAS. The VAS was significantly decreased on postoperative day 1 compared with the VAS recorded preoperatively (P < .05), indicating patients felt less pain on the day after surgery. The average VAS on postoperative day 1 from other studies for SV approach ranged from 2.1 to 5,9,12,14–19 whereas our MIV approach value was 3.17. Periarticular blocks were available for this study group, and no peripheral nerve blocks were used. Some studies of the SV approach mention the use of peripheral nerve blocks, while others did not describe the method used for treatment or control of postoperative pain. The decreased reported pain levels and the observed increased knee ROM seen in the MIV and SV approach study groups might be attributable to the treatment of postoperative pain.
Patient ambulation also increased from the day of surgery to the day of discharge for the MIV approach. Only 10% of patients were able to walk with assistance >200 feet on the day of surgery; however, this percentage increased to 65% on the discharge day showing an excellent recovery of walking ability within 2 days of surgery. Mehta and colleagues20reported that 95% of patients undergoing subvastus/midvastus approaches could walk >10 blocks at 6 months follow-up. For the MIV approach, 78% of patients were able to walk independently within 8 weeks of surgery.
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