The Central Quadriceps Free Tendon for Anterior Cruciate Ligament Reconstruction

Published on 11/04/2015 by admin

Filed under Orthopaedics

Last modified 22/04/2025

Print this page

This article have been viewed 1473 times

Chapter 15 The Central Quadriceps Free Tendon for Anterior Cruciate Ligament Reconstruction

John P. Fulkerson

Introduction

The central quadriceps has been used for anterior cruciate ligament reconstruction (ACLR) for more than 25 years.^1,² Stability results are similar to those with other autograft alternatives, but patients experience less pain and reach rehabilitation landmarks sooner.³ Staubli et al^4,⁵ have studied the anatomy and biomechanical properties of the quadriceps tendon. We became interested in this ACL graft in the early 1990s, first using it with bone⁶ but later discovering that it is a desirable free tendon graft option⁷ for ACLR. We wanted to avoid the risk of postoperative problems noted with bone–tendon–bone–patella tendon graft harvest,^8,⁹ were concerned about subtle weakness after taking out the medial hamstring tendons for ACLR in young athletes,¹⁰ and continue to worry about the possibility of prions in allograft tissue. We wanted to avoid these risks by using the central quadriceps free tendon (CQFT) for our ACLR. We confirmed and later reported the strength of the quadriceps tendon after harvesting the graft.¹¹ Our experience has remained very positive as we begin our 10th year with the CQFT graft. Also, patients frequently come into our office impressed with how little postoperative pain and difficulty they have compared with bone–tendon–bone and hamstring ACLR patients they encounter in physical therapy, as noted by Joseph et al³ in their short-term recovery study of ACLR patients.

Technique

We use the CQFT graft in all patients except those who specifically request another graft type, usually an allograft.

To harvest the CQFT, make a short 1.5- to 2-inch incision from the mid proximal patella upward (Fig. 15-1), and retract to view the quadriceps tendon. Retract slightly medially and note the vastus medialis obliquus (VMO). The graft should be taken preferentially from the thicker medial part of the quadriceps tendon but started proximally by retracting upward to the proximal VMO where the first incision is placed. Use a #10 scalpel blade and draw it distally at a 6- to 7-mm depth (just slightly less than the breadth of a #10 blade). The medial border of the graft then will usually be about 5 to 8 mm from the VMO at the level of the proximal patella.

Fig. 15-1 Exposure for quadriceps tendon graft harvest.

Place the second incision 9 to 11 mm lateral to the first at the level of the proximal patella and extend it proximally, keeping the blade at 90 degrees to the quadriceps tendon and at a 6- to 7-mm depth (the quadriceps tendon is about 9 mm thick).

After placing these incisions, place the tip of a hemostat at the desired depth beneath the CQFT, and spread the hemostat to separate the CQFT posterior fibers within the substance of the quadriceps tendon. This leaves a thin 1 mm of posterior quadriceps tendon attached to the synovium of the suprapatellar pouch. If the joint has been entered, the defect is then easily closed with this remaining tissue and synovium.

Properly done, you now have a piece of tendon that is about 6 to 7 mm thick and includes portions of the rectus and intermedius tendons. Note that there is a cleavage plane between these two components of the quadriceps tendon.

Keep spreading at the desired depth, and then dissect the tip of the graft at its insertion into the patella and release it without cutting any of the surrounding quadriceps tendon.

Grasp the released end of the quadriceps tendon with a uterine T clamp, and further dissect it proximally using a combination of blunt stripping and careful sharp dissection. We usually place two whipstitches ¹² with at least one Fiberwire (Arthrex, Naples, FL) in the released end and use this for traction during the dissection.

Release the CQFT graft proximally at 7 to 8 cm from the distal end. May scissors work best in our hands (Fig. 15-2).

Fig. 15-2 Release of the proximal end of the quadriceps tendon graft.

Troubleshooting Central Quadriceps Free Tendon Harvest

At first, harvesting the CQFT graft can seem a bit daunting until the surgeon becomes familiar with the anatomy, depth, and extent of the tendon. It is a very large, thick, and forgiving graft source. The quadriceps tendon is thickest near the VMO, so the harvest should be as close to the VMO as possible while avoiding all but the proximal muscle fibers of the VMO. Thus, think of the harvest as midline, starting at the proximal central aspect of the quadriceps tendon but 1 or 2 mm medially.

When first harvesting the graft, be sure to make an adequate incision. The incision gets smaller with experience. Define the graft borders carefully and try to avoid entering the pouch—you have a good 7 mm of tendon thickness to work with in almost every patient, but do not cut any deeper. If you do, cut all water flow, finish the harvest leaving the posterior fibers of quadriceps tendon, and run a continuous Vicryl suture along the synovium to close the defect before resuming arthroscopy.

Releasing the graft distally is easiest with a #15 scalpel blade. While retracting with the hemostat, you can define the insertion point of the graft on the patella nicely and release only the graft portion of the quadriceps tendon from the top of the patella.

A hemostat works well for defining the posterior border of the graft spread generously. If you do not obtain a thick-enough graft depth initially, place the hemostat a little deeper and define a larger, thicker graft as needed. The author prefers to use almost entirely blunt dissection after defining the borders, but a few careful clips with Metzenbaum scissors to aid the graft removal is usually helpful. Visualize all sides of the graft while stripping it out.

Keep the knee flexed to 90 degrees, with tension on the quadriceps tendon, during the entire harvest.

Use a uterine T clamp to grasp the end of the graft and then put #5 whipstitches in the free end, before stripping the graft proximally, to apply tension for the stripping. Use Mayo scissors to release the graft proximally under direct vision while retracting skin proximally and pulling the graft distally. As you release it, be careful not to flip the graft back into your face mask with the tension.

Take the graft to the back table and keep it under tension for whipstitching the other end, sizing it, and preparing it for placement in the knee.

Fixation of the Central Quadriceps Free Tendon Graft

We take the CQFT graft to the back table and place two sets of #5 whipstitches in each end using a combination of Ethibond or Ticron and Fiberwire. McKeon et al have shown that it is not necessary to place more than two whipstitch throws in each side of the tendon.¹² Use sizing cannulas (Fig. 15-3) to determine the size of the graft and the tunnels you will drill in the tibia and femur. In most cases, the graft will fit snugly into 8- or 9-mm tunnels.

Fig. 15-3 Sizing of the quadriceps tendon graft.

Next, place a circumferential mark on the graft at the point where it will exit the femoral socket (we like 2 cm of CQFT in the femoral socket). We prefer an Endobutton on the femoral end (Fig. 15-4), tying the #5 sutures (four strands off the end of the graft) after measuring the depth of the femoral tunnel such that the distance from the Endobutton to the marked femoral socket exit point on the graft is the same as the tunnel length, measured with the Endobutton depth gauge. Tie the sutures together (we use a Graftmaster to hold the graft and Endobutton during this process) with the knot just adjacent to the tendon graft (tying it elsewhere may cause problems in full deployment of the Endobutton).