Transtibial Pullout Repair of Lateral Meniscus Posterior Root Tear with Tissue Loss: A Case with Anterior Cruciate Ligament Injury and Medial Meniscus Tear

Abstract

Lateral meniscus (LM) posterior root tear (LMPRT) is mainly caused by trauma, especially trauma associated with anterior cruciate ligament (ACL) injuries. Although a transtibial pullout repair or a side-to-side repair is commonly performed for LMPRT, to the best of our knowledge, there is no clinical report of LMPRT with tissue loss using the pullout technique. Thus, the purpose of this report was to describe a clinical, radiographic, and arthroscopic outcome after pullout repair for a case of LMPRT with a large defect with a chronic ACL tear and complex medial meniscus (MM) tears. A 31-year-old man complained of knee pain and restricted range of motion after twisting his knee when he stepped on an iron pipe. The patient had a football-related injury to his right knee 14 years before presentation, and since then, the patient's knee has given out more than 10 times but was left unassessed. Magnetic resonance imaging showed LMPRT with tissue loss, ACL tears, and complex MM tears. Transtibial pullout repair of the LMPRT with ACL reconstruction and MM repairs were performed. Following the pullout repair of the LMPRT, an approximately 6 mm gap remained between the LM posterior root and root insertion. However, magnetic resonance imaging and second-look arthroscopy at 1 year postoperatively revealed meniscal healing, gap filling with some regeneration tissue, of the LM posterior root. Furthermore, the lateral meniscus extrusion in the coronal plane improved from 3.1 mm (preoperative) to 1.6 mm (1 year postoperatively). Transtibial pullout repair with the remaining gap could be a viable treatment option for LMPRT with tissue loss, combined with ACL reconstruction.

Figure 1

(a–d) Arthroscopic findings. (a) Chronic ACL tear. (b) The torn edge of the LMPR was defected. (c) Reduced MM bucket handle tear (white arrows) extending from the body to the posterior horn. (d) Complete radial tear of the posterior horn of the MM (black arrowhead). Abbreviations: LTP: lateral tibial plateau; LFC: lateral femoral condyle; p-MFL: posterior meniscofemoral ligament (Wrisberg ligament); MTP: medial tibial plateau; MFC: medial femoral condyle; MMPH: medial meniscus posterior horn.

Figure 2

(a–d) Arthroscopic findings and illustrations of the tunnel positions and postoperative three-dimensional computed tomography. (a) Repaired bucket handle tear of the MM. (b) Repaired radial tear of the posterior horn of the MM. (c) A 6 mm gap between the edge of the repaired LMPR and the bone aperture site remained. (d) Reconstructed ACL. (e) Illustration of the tunnel locations for the pullout repair of the LMPRT and the reconstruction of the AM bundle and the PL bundle. (f) The tibial tunnel for the LMPRT (arrowhead) was placed separately with a tunnel for the PL bundle (black arrow) and the AM bundle (white arrow).

Figure 3

Comparison of the (a–d) preoperative and (e–h) postoperative MRI findings. (a) Preoperative MRI showed a linear defect in the coronal plane (dotted area). (b) The length of the lateral meniscus extrusion (LME) was 3.1 mm (length between dashed lines). (c, d) The reference lines of the sagittal plane are shown as dotted lines in (a) (C and D, respectively). Ghost sign in two consecutive sagittal planes with a 10 mm interval (dashed area). (e) One year after the operation, the preoperative gap was filled with tissue continuous to the tibial attachment of the LMPR in the coronal plane. (f) The length of LME was 1.6 mm (1 year postoperatively). (g, h) The reference lines of the sagittal plane are shown as dotted lines in (e) (G and H, respectively). The disappearing ghost sign in two consecutive sagittal planes with a 10 mm interval (arrowhead).

Figure 4

Arthroscopic findings during the second-look arthroscopy. (a) Reconstructed ACL. (b) The repaired LMPR healed with continuity to its insertion site (arrow). (c) The repair sutures were cut out (arrowhead). (d) The synovial coverage around the root attachment. (e) The repaired MM bucket handle tear completely healed. (f) An approximately 1 cm defect remained at the central margin of the repaired radial tear (swallow-tail arrow).