By Jon Swenson, MD, FAAOS
What are the differences between the medial subvastus approach, the quad-sparing approach, the Southern approach, the Lightning Knee, and the Jiffy Knee for knee replacement?
Based on my research, I believe all five are essentially the same thing. Contrary to some claims, the subvastus approach is not new, but has more recently garnered new attention. The subvastus approach to the knee joint offers an alternative to traditional methods that require a large arthrotomy and partial division of the quadriceps mechanism. This approach was first described by Erkes in 1929 (2 Erkes, Bruns’ Beitr Klin Chir 1929) and popularized by Hoffman for use with total knee arthroplasties in 1991 (3 Hofmann et al. CORR Aug 1991).
The commonly accepted medical term in the orthopaedic literature for this technique is the subvastus approach to the knee. This technique and the others mentioned above describe approaching the knee by mobilizing the vastus medialis oblique (VMO) and moving it laterally in conjunction with the other quadriceps muscles. This preserves the integrity and function of the muscle by not having to cut through the inner border of the quadriceps tendon, which in turn separates the muscles and requires the surgeon to sew them back together at the end of the procedure.
The main advantage of the subvastus approach is that it does not cut the muscles or tendons around the knee and, therefore, is associated with a significant decrease in pain and swelling post-op. Because the muscle is not cut, less tissue trauma and inflammation allow the quadriceps muscle to recover faster. As a result, patients often experience less pain postoperatively and are able to begin physical therapy sooner, achieving their full range of motion in no time and a faster, more comfortable recovery.
Another advantage of the subvastus approach is that it better preserves the vascularity of the patella, as the superior and inferior medial genicular arteries are generally undisturbed during this technique. In addition, this approach does less to disrupt the tracking of the patella, diminishing the need for a lateral release. As a result, it can lead to improved knee function and reduced risk of complications, such as patellar dislocation or maltracking.
I performed my first subvastus total knee in the late 1990s, and it is currently my preferred method to replace most knees. Though a surgeon’s use of this approach will initially take a little longer to get the implants in place, it ultimately tends to be faster than the more traditional medial parapatellar approach in that the closure is quicker as there is less to repair at the end of the case (4 Endres, Minas, Brigham and Women’s Hospital).
Once a surgeon is accustomed to the procedure, I genuinely feel that this approach is associated with higher patient satisfaction. Since it can result in less scarring and a more aesthetically-pleasing incision site without directly incising the muscle, I have noticed less postoperative pain and swelling in patients and a faster return to their normal activities.
Jon Swenson, MD, FAAOS, is an orthopaedic surgeon at Hampton Roads Orthopaedics Spine and Sports Medicine specializing in sports medicine, arthroscopic surgery, and minimally invasive joint replacement surgery of the shoulder, knee and hip. hrosm.com
