Accuracy of the newly developed Zimmer Biomet Root Aiming guide in tibial tunnel creation compared with that of conventional guides

Abstract

Background/objective: Accurate tibial tunnel creation is crucial for successful transtibial pullout repair of medial meniscus (MM) posterior root tears (MMPRTs). This study aimed to evaluate the accuracy of the newly developed Zimmer Biomet Root Aiming (ZeBRA) guide for transtibial pullout repair of MMPRTs.

Methods: This study included 50 patients who underwent transtibial pullout repair using the Unicorn Meniscal Root (UMR) (n = 25) and ZeBRA (n = 25) guides. The expected anatomic centre (AC) and tibial tunnel centre (TC) were assessed using three-dimensional postoperative computed tomography (CT) images. The expected AC was defined as the centre of the circle tangent to the triangular footprint of the MM posterior root. The expected AC and TC on the tibial surface were assessed using the percentage-based posterolateral location on the tibial surface. The absolute distance between the AC and TC (mm) was evaluated.

Results: The mean AC location was 76.1% ± 3.1% posterior and 40.8% ± 2.1% lateral, whereas the mean TC location was 76.7% ± 5.3% posterior and 37.2% ± 3.6% lateral using the UMR guide and 75.8% ± 3.1% posterior and 36.5% ± 2.4% lateral using the ZeBRA guide. No significant difference was observed in the absolute distance between the UMR and ZeBRA guides (3.9 ± 1.4 and 3.8 ± 1.3 mm, respectively; p = 0.617).

Conclusions: The newly developed ZeBRA guide allows accurate tibial tunnel creation, and its accuracy is comparable to that of the conventional UMR guide. Tibial tunnels were created at optimal positions using both guides, and the choice of the guide would depend on the surgeon's preference.

Keywords: Meniscus; Musculoskeletal diseases; Orthopaedic procedures; Tibial tunnel; Zimmer biomet root aiming guide.

Fig. 1

Aiming guides (A) UMR (left) and ZeBRA (right) guides. The scale bars are marked at 5- and 10-mm points from the tip. (B) The underside of the UMR (left) and ZeBRA (right) guides. As can be seen, the ZeBRA guide is narrower than the UMR guide. (C) The ZeBRA guide with the handle and guide wire attached. The guide wire is pointing slightly anterior to the tip of the guide to prevent guide wire penetration. (D) The ZeBRA guide is compatible with the MTE aiming at the root attachment. (E) The distance between the drill sleeve and guide tip (black double-headed arrow) represents the tibial tunnel length and can be recognised by the scale bars marked in the drill sleeve (single-headed arrow). UMR: unicorn meniscal root; ZeBRA: Zimmer Biomet Root Aiming.

Fig. 2

Flow chart detailing the study protocol. Overall, 50 patients using the UMR (n = 25) and ZeBRA (n = 25) guides were included and retrospectively investigated. UMR: unicorn meniscal root; ZeBRA: Zimmer Biomet Root Aiming; MMPRTs: medial meniscus (MM) posterior root tears; K‒L: Kellgren‒Lawrence.

Fig. 3

Arthroscopic view during surgery (A) The scale is marked on the side of the guide. The marked value represents the distance from the guide tip. (B) A 10-mm line is set beside the posterior peak of the medial tibial eminence to create the tibial tunnel within the root attachment. (C) Suture relay technique for suture pullout. (D) Arthroscopic view after tibial fixation.

Fig. 4

The location of the AC and the TC (A) The small yellow and red circles indicate the expected AC and TC, respectively. (B) The large yellow circle is shown making contact with three anatomical bony landmarks. The difference in the mediolateral percentage between AC and TC was defined as the Δ M-L distance (%) and the anteroposterior percentage between AC and TC as the Δ A-P distance (%). AC: anatomic centre; TC: tibial tunnel centre. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)

Fig. 5

The locations of ACs. The mean position of the medial meniscus posterior root AC location was 76.1% ± 3.1% posterior and 40.8% ± 2.1% lateral (yellow square) on three-dimensional computed tomography images of the tibial surface. The white squares indicate the location in each case. AC: anatomic centre.

Fig. 6

Respective locations of the ACs and TCs. The yellow square denotes the mean AC, and the large black triangle and blue circle denote the mean TC using the UMR and ZeBRA guides, respectively. The small black triangle and small blue circle denote each TC using the UMR and ZeBRA guide, respectively. AC: anatomic centre; TC: tibial tunnel centre; UMR: unicorn meniscal root; ZeBRA: Zimmer Biomet Root Aiming