In vivo evaluation of femoral and tibial graft tunnel placement following all-inside arthroscopic tibial inlay reconstruction of the posterior cruciate ligament

[Effectiveness analysis of arthroscopic reconstruction of posterior cruciate ligament with embedded "tibial tendon bolt" fixation]

OBJECTIVE

To evaluate the effectiveness of arthroscopic reconstruction of posterior cruciate ligament (PCL) with embedded "tibial tendon bolt" fixation.

METHODS

The clinical data of 32 patients who underwent arthroscopic reconstruction of PCL using embedded "tibial tendon bolt" fixation through the tibial "8"-shaped tunnel between February 2012 and April 2016 were analyzed retrospectively. There were 23 males and 9 females, aged 15-57 years (mean, 39.9 years). The causes included traffic accident injury in 12 cases and sports injury in 20 cases. The clinical manifestations were swelling of knee joint, tenderness of knee joint space, and (+) Ⅲ degree in posterior drawer test; McMurry test (+) in 13 cases, valgus stress test (+) in 8 cases, Lachman test (+) in 9 cases, and Dial test (+) in 2 cases. The preoperative Lysholm score was 18.8±10.9, the International Knee Documentation Committee (IKDC) score was 18.0±15.2, and the detection value of KT-1000 was (14.34±2.73) mm. The time from injury to operation was 8-225 days, with a median of 11 days.

RESULTS

All 32 patients were followed up 25-36 months, with an average of 26.4 months. The patients had no tenderness of joint space, and the McMurry tests were all (-). At last follow-up, the Lysholm score and IKDC score were 90.2±2.4 and 87.2±6.2, respectively, which were significantly improved when compared with preoperative ones (t=-38.400, P<0.001; t=-27.190, P<0.001). The results of posterior drawer test were (-) in 21 cases, (+) Ⅰ degree in 9 cases, and (+) Ⅱ degree in 2 cases. At 1 and 2 years after operation, the detection value of KT-1000 were (5.56±2.28) mm and (5.87±1.78) mm, respectively, which were significantly improved when compared with preoperative values (P<0.05).

CONCLUSION

The application of arthroscopic reconstruction of PCL using embedded "tibial tendon bolt" fixation through the tibial "8"-shaped tunnel is an effective, simple, and safe surgical procedure.

Dynamic Three-Dimensional Computed Tomography Mapping of Isometric Posterior Cruciate Ligament Attachment Sites on the Tibia and Femur: Single- Versus Double-Bundle Analysis

PURPOSE

(1) To determine the area of posterior cruciate ligament (PCL) insertion sites on the lateral wall of the medial femoral condyle (LWMFC) that demonstrates the least amount of length change through full range of motion (ROM) and (2) to identify a range of flexion that would be favorable for graft tensioning for single-bundle (SB) and double-bundle (DB) PCL reconstruction.

METHODS

Six fresh-frozen cadaveric knees were obtained. Three-dimensional computed tomography point-cloud models were obtained from 0° to 135°. A point grid was placed on the LWMFC and the tibial PCL facet. Intra-articular length was calculated for each point on the femur to the tibia at all flexion angles and grouped to represent areas for bone tunnels of SB and DB PCLR. Normalized length changes were evaluated.

RESULTS

Femoral tunnel location and angle of graft fixation were significant contributors to mean, minimum, and maximum normalized length of the PCL (all p < .001). Tibial tunnel location was not significant in any case (all p < .22). A femoral tunnel in the location of the posteromedial bundle of the PCL resulted in the least length change at all tibial positions (maximum change 13%). Fixation of the anterolateral bundle in extension or at 30° flexion resulted in significant overconstraint of the PCL graft. The femoral tunnel location for a SB PCLR resulted in significant laxity at lower ranges of flexion.

CONCLUSION

PCL length was significantly dependent on femoral tunnel position and angle of fixation, whereas tibial tunnel position did not significantly contribute to observed differences. All PCL grafts demonstrated anisometry, with the anterolateral bundle being more anisometric than the posteromedial bundle. For DB PCLR, the posteromedial bundle demonstrated the highest degree of isometry throughout ROM, although no area of the LWMFC was truly isometric. The anterolateral bundle should be fixed at 90° to avoid overconstraint, and SB PCLR demonstrated significant laxity at lower ranges of flexion.

CLINICAL RELEVANCE

Surgeons can apply the results of this investigation to surgical planning in PCLR to optimize isometry, which may ultimately reduce graft strain and the risk of graft failure. Additionally, DB PCLR demonstrated superiority compared with SB PCLR regarding graft isometry, as significant laxity was encountered at lower ranges of flexion in SB PCLRs. Fixation of the ALB at 90° flexion should be performed to avoid overconstraint in knee extension.

Lower Tibial Tunnel Placement in Isolated Posterior Cruciate Ligament Reconstruction: Clinical Outcomes and Quantitative Radiological Analysis of the Killer Turn

Background

The "killer turn" effect after posterior cruciate ligament (PCL) reconstruction is a problem that can lead to graft laxity or failure. Solutions for this situation are currently lacking.

Purpose

To evaluate the clinical outcomes of a modified procedure for PCL reconstruction and quantify the killer turn using 3-dimensional (3D) computed tomography (CT).

Study design

Case series; Level of evidence, 4.

Methods

A total of 15 patients underwent modified PCL reconstruction with the tibial aperture below the center of the PCL footprint. Next, 2 virtual tibial tunnels with anatomic and proximal tibial apertures were created on 3D CT. All patients were assessed according to the Lysholm score, International Knee Documentation Committee (IKDC) Subjective Knee Evaluation Form, Tegner score, side-to-side difference (SSD) in tibial posterior translation using stress radiography, and 3D gait analysis.

Results

The modified tibial tunnel showed 2 significantly gentler turns (superior, 109.87° ± 10.12°; inferior, 151.25° ± 9.07°) compared with those reconstructed with anatomic (91.33° ± 7.28°; P < .001 for both comparisons) and proximal (99° ± 7.92°; P = .023 and P < .001, respectively) tibial apertures. The distance from the footprint to the tibial aperture was 16.49 ± 3.73 mm. All patient-reported outcome scores (mean ± SD) improved from pre- to postoperatively: Lysholm score, from 46.4 ± 18.87 to 83.47 ± 10.54 (P < .001); Tegner score, from 2.47 ± 1.85 to 6.07 ± 1.58 (P < .001); IKDC sports activities score, from 19 ± 9.90 to 33.07 ± 5.35 (P < .001); and IKDC knee symptoms score, from 17.87 ± 6.31 to 25.67 ± 3.66 (P < .001). The mean SSD improved from 9.15 ± 2.27 mm preoperatively to 4.20 ± 2.31 mm postoperatively (P < .001). The reconstructed knee showed significantly more adduction (by 1.642°), less flexion (by 1.285°), and more lateral translation (by 0.279 mm) than that of the intact knee (P < .001 for all).

Conclusion

Lowering the tibial aperture during PCL reconstruction reduced the killer turn, and the clinical outcomes remained satisfactory. However, SSD and clinical outcomes were similar to those of previously described techniques using an anatomic tibial tunnel.

Variation in Graft Bending Angle During Range of Motion in Single-Bundle Posterior Cruciate Ligament Reconstruction: A 3-Dimensional Computed Tomography Analysis of 2 Techniques

PURPOSE

To compare variations in femoral graft bending angle during range of motion (ROM) of the knee between inside-out (IO) and retro-socket outside-in (OI) techniques in posterior cruciate ligament (PCL) reconstruction using in vivo 3-dimensional (3D) computed tomography analysis.

METHODS

Ten patients underwent PCL reconstruction by the IO technique (5 patients) or the retro-socket OI technique (5 patients) for suspensory femoral fixation. After PCL reconstruction, 3D computed tomography was performed in 0° extension and 90° flexion to reconstruct 3D femur and tibia bone models using Mimics software. Positions of femur and tibia at 30°, 45°, and 60° flexion were reproduced by determining the kinematic factors of anteroposterior translation, mediolateral translation, and internal-external rotation angle of each patient based on previously measured kinematic data. Variation in graft bending angle according to the flexion range of the knee was calculated by the difference in graft angulation measured at each flexion angle. The results were compared between the 2 techniques.

RESULTS

There was significant difference in variation of femoral graft bending angle between IO and retro-socket OI techniques from 0° to 90° flexion of the knee (P = .008). Significant difference was also noticed at 30° to 45° (P = .008), 45° to 60° (P = .008), and 60° to 90° (P = .016) ROM of the knee between the 2 groups.

CONCLUSIONS

The retro-socket OI technique resulted in less variation in femoral graft bending angle compared with the IO technique during knee ROM. We recommend the retro-socket OI technique for femoral tunnel placement to reduce the graft motion at the intra-articular femoral tunnel aperture.

CLINICAL RELEVANCE

The retro-socket OI technique produces significantly less variation in femoral graft bending angle when compared with the IO technique. Such reduction in variation of femoral graft bending angle might be related to lower stress at the femoral tunnel aperture.

Bony landmark between the attachment of the medial meniscus posterior root and the posterior cruciate ligament: CT and MR imaging assessment

OBJECTIVES

(1) To reveal the prevalence of the bony recess (posterior dimple) and (2) to determine the position of the posterior dimple on the tibial plateau using three-dimensional computed tomography (3DCT).

MATERIALS AND METHODS

In this study, a retrospective review of 112 patients was performed to identify the posterior dimple and to evaluate its position on 3DCT. Magnetic resonance images (MRIs) were also used to determine the positional relationship among the posterior cruciate ligament (PCL), medial meniscus posterior insertion (MMPI), and posterior dimple.

RESULTS

The posterior dimple was observed in 100 of 112 knees (89.3%) on 3DCT. The center of the posterior dimple was 13.6 ± 0.8 mm from the medial tibial eminence apex. MRI showed that the posterior dimple separated the tibial attachment of the PCL and MMPI.

CONCLUSION

This is the first study to discuss the prevalence and position of the bony recess in the posterior intercondylar fossa.