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A Retrospective Analysis of the Modified Intervastus Approach

December 17, 2018 | Surgery
Muthana Sartawi, MD ; Hafizur Rahman, PhD ; James Kohlmann, MD ; Ross Leighton, MD ; Mariana E. Kersh, PhD
Author and Disclosure Information

Dr. Sartawi is an orthopedic surgeon, Assistant Professor, University of Illinois College of Medicine, Champaign, Illinois. Dr. Rahman is a Postdoctoral Research Fellow, Department of Biomechanics, University of Nebraska at Omaha, Omaha, Nebraska. Dr. Kohlmann is an orthopedic surgeon, Department of Surgery, Sarah Bush Lincoln Health Center, Mattoon, Illinois. Dr. Leighton is orthopedic surgeon, Professor of Surgery at Dalhousie University in Halifax, Nova Scotia, Canada. Dr. Kersh is an Assistant Professor, Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois.

Authors’ Disclosure Statement:  The authors report no actual or potential conflict of interest in relation to this article.

Address correspondence to: Hafizur Rahman, Department of Biomechanics, 6160 University Drive South (tel, 402-554-3228; email, hrahman@unomaha.edu).

Muthana Sartawi, MD Hafizur Rahman, PhD James Kohlmann, MDRoss Leighton, MD Mariana E. Kersh, PhD . A Retrospective Analysis of the Modified Intervastus Approach. Am J Orthop.

December 17, 2018

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.

Total knee arthroplasty (TKA) is one of the most common orthopedic surgical procedures, with more than 600,000 TKAs performed annually in the United States, and by 2030 the number is expected to reach 3.48 million per year.1Several approaches have been described for total TKA, and the medial parapatellar (MP) approach to the knee is considered the workhorse of total knee replacements. It is an extensile approach that is easy to perform but may delay active knee extension and straight-leg raise after surgery.2  Alternative approaches such as the subvastus (SV) and midvastus approaches to the knee (Figure 1A) typically allow a more rapid straight-leg raise but may be more challenging to perform and time-consuming in morbidly obese patients, muscular patients, and patients with severe deformities.3

The intervastus approach (Figure 1A) described by Jojima4 and others utilizes the interval between the quadriceps tendon and vastus medialis. Although it is a simple approach to perform that is extensile, it is not considered tendon-sparing since the vastus medialis inserts onto the medial aspect of the quadriceps tendon (Figure 2).5  Therefore, dissecting through this interval, without elevation of the vastus medialis (Figure 3A), damages the quadriceps tendon, and strangulation of the muscle occurs with repair of the arthrotomy site (Figure 3B).  This situation is even more likely in patients with a low-lying vastus medialis.6

The modified intervastus (MIV) approach described previously,7 may be used in the majority of patients undergoing TKA. The advantages of this approach include its extensile nature, similarities to an MP approach, and preservation of both the extensor mechanism and the vastus medialis, leading to a more rapid return to active knee extension than is traditionally observed.2,7 The approach is simple to perform, easy to close, and is compatible with more extensile approaches such as a quadriceps snip if required in revision scenarios.7 However, functional outcomes of the MIV approach have not been quantified. It is unknown whether these outcomes will offer any advantages compared with the SV approach. Therefore, the objective of this study was to measure functional outcomes of the MIV approach and to compare the results with those previously published for the SV approach. We hypothesized that using the MIV approach for TKA surgery would lead to early straight-leg raise and increase in knee range of motion (ROM) postoperatively.

SURGICAL TECHNIQUE

The MIV approach preserves the quadriceps tendon and vastus medialis.7 After exposure of the vastus medialis muscle, the interval between the quadriceps tendon and vastus medialis is identified (Figure 4).  The fascia overlying the lateral edge of the vastus medialis is incised where it meets the quadriceps tendon (Figure 5).  The muscle is then bluntly elevated off the underlying capsule just enough to allow for a capsular repair later (Figure 6).  An arthrotomy is then performed from cephalad to caudal (Figure 7).  This interval may be extended proximally between the vastus intermedius and vastus medialis to expose the distal femur if needed. The closure is performed by repairing the capsule with absorbable suture (Figure 8A), and the vastus medialis fascia is repaired back to the medial edge of the quadriceps tendon, restoring the anatomy (Figure 8B).

Continue to: PATIENTS AND METHODS...

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