Change of the tunnel configuration in the non-anatomic trans-tibial double bundle ACL reconstruction

Editorial Commentary: Revision of Failed Double-Bundle Anterior Cruciate Ligament Reconstruction

Double-bundle (DB) reconstruction of the anterior cruciate ligament was favored for several years. However, recent studies increasingly show that this technique does not provide a clear advantage over the less-invasive single-bundle technique. Unfortunately, the graft fails relatively often after ACL reconstruction. Postoperative communication of the bone tunnels through bone tunnel widening is possible. Since 2 drill channels are created in the DB technique, femoral as well as tibial, it is assumed that this technique may cause problems during revision. So, in part, revision may require a 2-step procedure with bone graft filling of the tunnels as the first step. It is important that surgeons with experience using DB publish their revision strategies and experiences.

Comparison of the aperture and midportion femoral tunnel widening after anterior cruciate ligament reconstruction: A systematic review and meta-analyses

BACKGROUND

To identify whether the aperture or the midportion of the femoral tunnel had a larger tunnel widening in patients who undergo ACL reconstruction.

METHODS

PubMed, EMBASE and Cochrane Library were searched for relative studies that evaluated tunnel widening in patients underwent arthroscopic ACL reconstruction. Two reviewers independently recorded data from each study, including the sample size and magnitude of tunnel widening. Random-effects meta-analyses were performed to pool the outcomes of tunnel widening by estimating the standardized mean differences in tunnel widening and their 95% confidence intervals (CIs), Publication bias was assessed using funnel plots and Egger test when the number of included studies was >10.

RESULTS

Eleven included studies compared tunnel widening between the aperture and the midportion. In these studies, 372 and 92 patients underwent single- and double-bundle ACL reconstructions, respectively. Subgroup analyses in terms of evaluation imaging tool for tunnel widening showed no significant differences in tunnel widening between the aperture and the midportion of the femoral tunnel regardless of plain radiograph (mean difference, 0.02 mm; P = .97), computed tomography (mean difference 0.08 mm; P = .55), and magnetic resonance imaging (mean difference, 0.13 mm; P = .78). Likewise, no significant difference in femoral tunnel widening was found between the aperture and the midportion, irrespective of transtibial (mean difference, 0.18 mm; P = .57), anteromedial (mean difference, 0.02 mm; P = .90), and outside-in techniques (mean difference, 0.01 mm; P = .98).

CONCLUSION

No significant difference in femoral tunnel widening was found between the aperture and the midportion in the patients who underwent ACL reconstruction.

Evaluation of the Length and Isometric Pattern of the Anterolateral Ligament With Serial Computer Tomography

BACKGROUND

Recent anatomical studies have identified the anterolateral ligament (ALL). Injury to this structure may lead to the presence of residual pivot shift in some reconstructions of the anterior cruciate ligament. The behavior of the length of this structure and its tension during range of motion has not been established and is essential when planning reconstruction.

PURPOSE

To establish differences in the ALL length during range of knee motion.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Ten unpaired cadavers were dissected. The attachments of the ALL were isolated. Its origin and insertion were marked with a 2 mm-diameter metallic sphere. Computed tomography scans were performed on the dissected parts under extension and 30°, 60°, and 90° of flexion; measurements of the distance between the 2 markers were taken at all mentioned degrees of flexion. The distances between the points were compared.

RESULTS

The mean ALL length increased with knee flexion. Its mean length at full extension and at 30°, 60°, and 90° of flexion was 37.9 ± 5.3, 39.3 ± 5.4, 40.9 ± 5.4, and 44.1 ± 6.4 mm, respectively. The mean increase in length from 0° to 30° was 3.99% ± 4.7%, from 30° to 60° was 4.20% ± 3.2%, and from 60° to 90° was 7.45% ± 4.8%. From full extension to 90° of flexion, the ligament length increased on average 16.7% ± 12.1%. From 60° to 90° of flexion, there was a significantly higher increase in the mean distance between the points compared with the flexion from 0° to 30° and from 30° to 60°.

CONCLUSION

The ALL shows no isometric behavior during the range of motion of the knee. The ALL increases in length from full extension to 90° of flexion by 16.7%, on average. The increase in length was greater from 60° to 90° than from 0° to 30° and from 30° to 60°. The increase in length at higher degrees of flexion suggests greater tension with increasing flexion.

CLINICAL RELEVANCE

Knowledge of ALL behavior during the range of motion of the knee will allow for fixation (during its reconstruction) to be performed with a higher or lower tension, depending on the chosen degree of flexion.