Chapter 40 Anatomical Retroscrew Anterior Cruciate Ligament Fixation

Single- and Double-Bundle Anterior Cruciate Ligament Reconstruction with Retroscrew Biointerference in a Single Femoral Socket

Steven Gorin, Craig D. Morgan, David Caborn

The concept of anatomic graft positioning for anterior cruciate ligament reconstruction (ACL) has been previously described by many authors.¹^–⁶ In the past, anatomical graft tunnels were believed to obtain an optimal ACL reconstruction; the position of the graft within bone tunnels had to avoid the intercondylar roof and wall impingement. Studies have documented the landmarks for the placement of endoscopic tunnels in anatomical reconstructions through a full knee range of motion that will avoid impingement.^7,⁸

Recently, issues regarding graft fixation position have become important. Experimental and clinical trials have shown that anatomical graft fixation and position at or near the origin and insertion of the native ACL in contrast to nonanatomical fixation position will (1) minimize graft tension, (2) minimize graft length change, (3) produce a more stable reconstruction through full knee range of motion, and (4) avoid anteroposterior, sagittal, windshield wiper–type graft motion.^1,^2,^4,⁷^–¹⁰ Five-year follow-up studies comparing anatomical and nonanatomical fixation for ACL reconstruction have shown absence of tunnel expansion up to 5 years with an anatomically fixed graft at the intraarticular tibial tunnel orifice (Fig. 40-1)^5,^6,^8,^11,¹²

Fig. 40-1 A, An all-inside anterior cruciate ligament (ACL) reconstruction with a quadriceps tendon autograft fixed anatomically at the intraarticular tibial and femoral socket orifices. Retrograde and antegrade headed titanium interference screws (Arthrex) were used in the tibial and femoral sockets, respectively. B, A lateral radiograph of the same case illustrating anatomical interference screw positioning.

The Retroscrew (Arthrex, Naples, FL) (Fig. 40-2) is inserted into the tibial tunnel in an inside-out position so that the head of the screw achieves aperture fixation at the intraarticular tunnel orifice. Standard interference screw fixation is used on the femoral side. The Retroscrew is beneficial during tensioning because unlike an antegrade screw, the Retroscrew will pull the graft tighter into the tunnel, especially during tensioning.

Fig. 40-2 The femoral and tibia Retroscrews are shown. The screws are tethered by a #2 Fiberwire suture.

Morgan et al ⁴ first described an “all-inside” technique for ACL reconstruction that addressed the issues of anatomical fixation. However, the procedure was not popular because of its technically demanding nature^3,^5,^6,¹³ (Fig. 40-3).