A 31-year-old male, currently working as a long-distance driver, injured his right knee by stepping on an iron pipe, resulting in his knee twisting. The patient had also injured his right knee while playing football 14 years before presentation, for which he received conservative management. Since then, the patient's knee gave out more than 10 times but was left unassessed.
The patient's chief complaint was right-knee pain, limited range of motion in the knee, and painful movement. The Lachman test and pivot shift test yielded positive results. Preoperative radiographs were normal, and the posterior tibial slope was 7 . Magnetic resonance imaging (MRI) revealed an ACL rupture, an LMPRT concomitant with LM extrusion, and MM tears.
An arthroscopic evaluation revealed that the ACL was torn, with only the scar tissue remaining (Figure 1(a)). The LM posterior root (LMPR) was detached and defected about more than 12 mm (Figure 1(b)). The posterior meniscofemoral ligament was intact. After reduction of the displaced MM, the bucket handle tear of the MM extended from the body to the posterior horn (Figure 1(c)). The complete radial tear at the posterior horn of the MM extended from the central to the peripheral lesion near the bucket handle tear (Figure 1(d), supple Fig. 1).
We first implemented the outside-in pie-crusting technique using a standard 18-gauge (1.2 x 40 mm) hypodermic needle (TERUMO, Tokyo, Japan) to increase the medial joint space. After reduction of the displaced MM into its appropriate anatomic position, 6 sutures were performed using 2-0 Wayolax (Matsuda Ika Kogyo, Tokyo, Japan) using the inside-out technique in the vertically stacked way for the bucket handle tear (Figure 2(a)). Following the repair of the bucket handle tear, a cross-stitch with two perpendicular sutures in an "X" configuration was performed using 2-0 Wayolax sutures using inside-out technique for the radial tear (Figure 2(b)).
We performed a transtibial pullout repair for LMPRT using two simple stitches. A Knee Scorpion suture passer (Arthrex, Naples, Florida, USA) was used to pass two No. 2 Ultrabraid  sutures (Smith & Nephew, Andover, Massachusetts, USA) vertically through the meniscal tissue. We made an additional bone tunnel in the center of the root attachment, which was about 4 mm medial and 1.5 mm posterior from the lateral tibial eminence, as previously reported by Johannsen et al. in a cadaveric anatomical study. A 2.4 mm guide pin was inserted using an Acufex Director Elite  ACL drill guide system (Smith & Nephew), aiming at the center of the root attachment. The sutures were retrieved through the additional tunnel and tied under the 5.0 mm cancellous screw inserted at the tibia with the knee flexed at 20  with an initial tension of 20 N after ACL reconstruction. Following the procedure, an approximately 6 mm gap between the edge of the LMPR and the root insertion site remained (Figure 2(c)).
We performed double-bundle reconstructions with semitendinosus autografts using the outside-in technique. The femoral tunnel was created using an anterolateral portal entry femoral aimer and an Acufex Director Elite  ACL drill guide system. Femoral tunnels were created with a 6 mm diameter reamer for the anteromedial (AM) bundle and a 5.5 mm diameter reamer for the posterolateral (PL) bundle. The tibial aiming guide was set at 45  for the AM bundle and 55  for the PL. Tibial tunnels were created with a 6.0 mm diameter reamer for the AM and PL bundles. The two bundles were passed from the tibial tunnel to the femoral tunnel through two leading sutures using the EndoButton CL device (Smith & Nephew) (Figure 2(d)). The tibial fixation was performed with the knee flexed at 20 , with an initial tension of 30 N for the AM bundle and in full extension with 20 N for the PL bundle. These bundles were fixed using the tenodesis screw (Arthrex), and the passing sutures were tied under the 5.0 mm cancellous screw, similar to the repair suture for LMPRT (Figure 2(e)). The aperture location of the tibia was confirmed by computed tomography examination after the surgery (Figure 2(f)).
The patient was initially nonweight-bearing with a limited-motion knee brace. At 3 weeks postoperatively, 1/3 partial weight-bearing was permitted, with progression to full weight at 5 weeks postoperatively. The patient was allowed 90  knee flexion at 2 weeks postoperatively, 120  at 3 weeks postoperatively, and deep flexion at 5 weeks postoperatively. Jogging was allowed following a muscle strength check at 4 months postoperatively. Sports activities were allowed at 9 months postoperatively.
Preoperative MRI of the coronal plane revealed the tissue loss of the LMPRT (Figure 3(a)), and the length of the LM extrusion (LME) was 3.1 mm (Figure 3(b)). The tissue loss of LMPRT was also found in sagittal planes with a 10 mm interval as a ghost sign (Figures 3(c) and 3(d)). MRI and the second-look arthroscopy were performed 1 year postoperatively. The one-year postoperative MRI of the coronal plane revealed continuous tissue regeneration, and the LME improved to 1.6 mm (Figures 3(e) and 3(f)). The regeneration tissue was also found in postoperative MRI of sagittal planes with a 10 mm interval as a disappearing ghost sign. The regeneration tissue might be small; the signal intensity was slightly high in T2 fat saturation serials (not similar in signal to the normal meniscus) but had a triangular shape in the sagittal plane (Figures 3(g) and 3(h)). Second-look arthroscopy at 12 months postoperatively revealed that the maturation of the reconstructed ACL graft was good, with good graft integrity, tension, and synovial coverage (Figure 4(a)). The repaired LMPR healed with continuity to the root attachment (Figures 4(b)-4(d)), although the repair sutures were cutout (Figure 4(c)), and synovial coverage around the root attachment was found (Figure 4(d)). The MM bucket handle tear was completely healed (Figure 4(e)); however, an approximately 1 cm defect remained at the central margin of the radial tear, needing marginal debridement (Figure 4(f)). The side-to-side difference of the anterior tibial translation measured by a KT-2000 arthrometer was not found in both knees. At the final follow-up performed 2 years after the first operation, the clinical outcome had improved compared to the preoperative status (Table 1).