Anterior Cruciate Ligament Reconstruction With Bone-Patellar Tendon-Bone Graft Through a Rectangular Bone Tunnel Made With a Rectangular Retro-dilator: An Operative Technique

Flat-Tunnel Technique With Independently Tensioned Bundles Better Restores Rotational Stability Than Round-Tunnel Technique in Anatomic Anterior Cruciate Ligament Reconstruction Using Hamstring Graft: A Cadaveric Biomechanical Study

PURPOSE

To investigate the kinematics differences between round-tunnel (ROT) and flat-tunnel (FLT) techniques in anterior cruciate ligament (ACL) reconstruction when using hamstring graft.

METHODS

Nine matched pairs of fresh-frozen cadaveric knees were evaluated for the kinematics of intact, ACL-sectioned, and either ROT or FLT reconstructed knees. The graft bundles for FLT technique were separately tensioned. A 6 degrees of freedom robotic system was used to assess knee laxity: (1) 134-N anterior tibial load at 0°, 15°, 30°, 60°, and 90°of knee flexion; (2) 10 Nm of valgus torque followed by 5 Nm of internal rotation torque simulates a pivot-shift test at 15° and 30°; (3) 5-Nm internal and external rotation torques at 0°, 15°, 30°, 60°, and 90°; (4) 10-Nm varus and valgus torques at 15° and 30°.

RESULTS

Significant differences were found for ROT versus FLT techniques in terms of the simulated pivot-shift test at 15° (2.5 mm vs 1.4 mm, respectively, difference from intact; P =.039) and the internal rotation test at 15° (2.5° vs 0.5°, respectively, difference from intact; P =.034) and 30° (2.0° vs 0.4°, respectively, difference from intact; P =.014). No significant differences were found between groups during 134-N anterior tibial load, external rotation and valgus/varus rotation. Neither technique was able to reproduce the intact state during an anterior tibial load and simulated pivot-shift test.

CONCLUSIONS

The FLT technique with independently tensioned bundles shows the same anterior control as the ROT technique but better restores rotational stability in terms of the simulated pivot-shift test and the internal rotation test in anatomic ACL reconstruction at time zero.

CLINICAL RELEVANCE

The FLT technique with independently tensioned bundles of ACL reconstruction appears to be a viable, more anatomic technique than the ROT technique in mimicking flat anatomy and rotational stability of native ACL.

Technical note: rectangular femoral tunnel for anterior cruciate ligament reconstruction using a new ultrasonic device: a feasibility study

PURPOSE

The goal of this preliminary report was to show the use of novel Ultrasound (US) technology for anterior cruciate ligament (ACL) reconstruction surgery and evaluate its feasibility for the creation of a rectangular femoral bone tunnel during an arthroscopic procedure in a human cadaver model.

METHODS

Two fresh frozen human cadaver knees were prepared for arthroscopic rectangular femoral tunnel completion using a prototype US device (OLYMPUS EUROPA SE & CO. KG). The desired rectangular femoral tunnel was intended to be located in the femoral anatomical ACL footprint. Its tunnel aperture was planned at 10 × 5 mm and a depth of 20 mm should be achieved. For one knee, the rectangular femoral tunnel was realized without a specific cutting guide and for the other with a 10 × 5 mm guide. One experienced orthopedic surgeon performed the two procedures consecutively. The time for femoral tunnel completion was evaluated. CT scans with subsequent three-dimensional image reconstructions were performed in order to evaluate tunnel placement and configuration.

RESULTS

In the two human cadaver models the two 10 × 5x20mm rectangular femoral tunnels were successfully completed and located in the femoral anatomical ACL footprint without adverse events. The time for femoral tunnel completion was 14 min 35 s for the procedure without the guide and 4 min 20 s with the guide.

CONCLUSION

US technology can be used for the creation of a rectangular femoral bone tunnel during an arthroscopic ACL reconstruction procedure. The use of a specific cutting guide can reduce the time for femoral tunnel completion. Additional experience will further reduce the time of the procedure.

Differences in the Development of Fibrocartilage Layers in the Quadriceps Tendon and Patellar Tendon Insertions in Rabbits: A Quantitative Study

Background

Differences in the development of fibrocartilage layers in quadriceps tendon (QT) and patellar tendon (PT) insertion sites are unclear. Because the mechanical environments for the QT and PT are different, the development of the QT and PT insertions may differ.

Purpose

To investigate differences in the development of fibrocartilage layers in the QT and PT insertion sites in rabbits through use of quantitative morphometric evaluations.

Study Design

Descriptive laboratory study.

Methods

This study included 54 male Japanese White rabbits. Animals were euthanized at ages 1 day and 1, 2, 3, 4, 6, 8, 12, and 24 weeks (n = 6 for each age). Chondrocyte number, proliferation, apoptosis, sex-determining region Y box 9 (Sox9)-positive rates, safranin O-stained glycosaminoglycan (GAG) areas, tidemark length, insertion width, and patellar length were evaluated and compared with the same parameters at age 24 weeks and between QT and PT insertion sites.

Results

Chondrocyte proliferation was low up to age 2 weeks for QT insertion and low up to 1 week for PT insertion. Chondrocyte apoptosis was high at 1 day and Sox9 expression was low up to 1 week for PT insertion. Sox9 expression was higher in QT than in PT insertion at age 12 weeks. The high chondrocyte count continued to age 1 day in PT insertion and up to 6 weeks in QT insertion. The chondrocyte number was higher in QT than in PT insertion at age 2 weeks. The period of thicker GAG lasted from 2 to 8 weeks in PT insertion and from 1 to 12 weeks in QT insertion. GAG thickness in QT insertion was higher than in PT insertion at age 4 and 12 weeks.

Conclusion

Development of fibrocartilage layers in QT and PT insertion sites was completed at age 24 weeks in rabbits. However, the period of high chondrocyte count and period of thicker GAG were longer in QT than in PT insertion up to 12 weeks.

Clinical Relevance

Development of fibrocartilage layers in QT and PT insertions differed in rabbits. Our results may contribute to the development of appropriate treatments based on age and the development of methods for regeneration of the insertion.

Positioning the femoral bone socket and the tibial bone tunnel using a rectangular retro-dilator in anterior cruciate ligament reconstruction

Purpose

The purpose of this study was to evaluate the positions of femoral bone sockets and tibial bone tunnels made with the rectangular retro-dilator (RRD), which we manufactured for anterior cruciate ligament reconstruction (ACLR) with a bone-patella tendon-bone (BPTB) graft which is fixed into the rectangular bone socket and tunnel made at anatomical ACL insertion sites.

Methods

42 patients who had undergone ACLR with BPTB using the RRD were evaluated to assess bone socket and tunnel positions by the quadrant method and Magnussen classification using three-dimensional (3-D) CT. Intra-operative complications were also investigated in all patients.

Results

3-D CT of the operated knee joints using the RRD showed that the bone socket and tunnel were placed in anatomical positions. In the quadrant method, the mean position of the femoral bone socket aperture was located at 22.0 ± 4.2% along the Blumensaat’s line, and 37.4 ± 7.2% across the posterior condylar rim. The mean positions of the tibial bone tunnel aperture were 37.7 ± 5.2% and 46.1 ± 2.2% antero-posteriorly and medio-laterally, respectively. In addition, according to the Magnussen classification, 39 cases were evaluated as type 1, and almost all were located behind the lateral intercondylar ridge (also known as the resident’s ridge). 3 cases were classified as type 2, which overlapped with the resident’s ridge. A partial fracture of BPTB bone fragment was observed in 2 patients, but no serious complications including neurovascular injury were observed.

Conclusion

The study indicates that the use of RRD achieves a safe anatomical reconstruction of the ACL.

Morphology of the patellar tendon and its insertion sites using three-dimensional computed tomography: A cadaveric study

BACKGROUND

To clarify, with three-dimensional (3D) images, the morphological properties of the patellar tendon and both of its insertion sites.

METHODS

Thirty-two human cadaveric left knees were evaluated, and 3D computed tomography images were created. These images were used to analyse the morphology of both insertion sites of the patellar tendon, and the width, length and thickness of each region of the patellar tendon.

RESULTS

The insertion sites of the patellar tendon on the patellar and tibial sides were V-shaped and crescent-shaped, respectively, with the respective bony apexes located at 44.5 ± 2.2% (standard deviation) and 35.5 ± 2.8% of the tendon width from its medial edge. The proximal, central and distal widths of the patellar tendon were 29.9 ± 2.7 mm, 27.3 ± 2.5 mm and 25.0 ± 2.4 mm, respectively. The length of the patellar tendon was shortest at 40.6% ± 6.7% of the central width and gradually became longer toward both edges. The patellar tendon was thickest in the central portion of 40-75% and gradually became thinner toward both edges.

CONCLUSIONS

The morphological properties of the patellar tendon and its insertion sites on both the patellar and tibial sides were consistent. These findings indicate that the characteristics of the bone-patellar tendon-bone graft markedly depend on the location from which it is harvested, and that these characteristics contribute to predicting the length, width and shapes of the bone plugs of the graft when performing bone-patellar tendon-bone surgery.

No Difference between Extraction Drilling and Serial Dilation for Tibial Tunnel Preparation in Anterior Cruciate Ligament Reconstruction: A Systematic Review

Importance

This review highlights a lack of consensus and need for further study regarding optimal tibial tunnel preparation method in anterior cruciate ligament reconstruction (ACLR).

Objective

This review examines existing clinical and biomechanical outcomes of both extraction drilling (ED) and serial dilation (SD) as a technique for tibial tunnel preparation in ACLR.

Evidence Review

In accordance with PRISMA guidelines, three electronic databases (MEDLINE, EMBASE, and PubMed) were searched and systematically screened in duplicate from database inception to September 6, 2017 for English-language, human studies, of all levels of evidence that examined ED and/or SD for tibial tunnel preparation in ACLR. Data including patient demographics, tibial tunnel preparation techniques, biomechanical and clinical outcomes and complications were retrieved from eligible studies.

Findings

ED was used in 71 patients, who were mean age 29.9 years (range: 17-50), 68% male, and followed for mean 16.5 months (range: 3.8-46). SD was used in 70 patients (70 knees), who were mean age 29.3 years (range: 18-50), 69% male, and followed for mean 14.1 months (range: 3.8-46). There were no statistically significant differences (mean preoperative; mean postoperative) for either tibial preparation technique for Lysholm (50.1; 92.5), Tegner (3.5; 6.1), International Knee Documentation Committee (IKDC) (48.8; 92.7), and Lachman or laxity scores. However, ED demonstrated statistically significant increased postoperative tibial tunnel expansion (1.8 mm versus 1.4 mm) and (at 12 weeks) graft migration at the tibial fixation site (1.3 mm versus 0.8 mm). Across biomechanical studies, there were no statistically significant differences (ED; SD) with forces required to initiate graft slippage (156 N; 174 N), graft stiffness (187 N; 186.5 N), and screw torque (1.6 N/m; 1.8 N/m). ED demonstrated a lower mean load to failure for the graft construct (433 N versus 631 N; p<0.05).

Conclusions and Relevance

Though biomechanical data demonstrated lower mean load to failure for the graft using ED, clinical data suggest increased tibial tunnel expansion and post-operative graft migration at the tibial fixation site. Future studies with long-term follow-up data are required to ascertain the optimal technique for graft incorporation and postoperative success.

Level of Evidence

IV:Systematic Review of Level I-IV studies.

Bone-to-bone integrations were complete within 5 months after anatomical rectangular tunnel anterior cruciate ligament reconstruction using a bone-patellar tendon-bone graft

PURPOSE

Anterior cruciate ligament (ACL) reconstruction using a bone-patellar tendon-bone (BTB) graft is known to provide secure fixation due to the direct bone-to-bone integration of the bone plug and bone tunnel. It is important to know the time required for bone integration when designing the postoperative rehabilitation protocol or deciding when the patient can return to competition-level activity, especially if the patient is an athlete. However, because reports are scarce, the period necessary for bone-to-bone integration after ACL reconstruction using a BTB graft remains unclear. The purpose of this study was to clarify this issue. It was hypothesised that ACL reconstruction using a BTB graft via an anatomical rectangular tunnel would help in the integration between bone plugs and bone tunnels on both the femoral and tibial sides after at least 6 months, at which point basic exercises similar to pre-injury sporting activity levels can be resumed.

METHODS

This study included 40 knees treated with ACL reconstruction using a BTB graft via anatomical rectangular tunnel reconstruction between 2013 and 2014 in a single institute. The integration between bone plugs and bone tunnels was evaluated using multi-slice tomosynthesis, which is a technique for producing slice images using conventional radiographic systems, at 1, 3, and 5 months postoperatively. All procedures were performed by two experienced surgeons. Bone integration was evaluated by two orthopaedic doctors.

RESULTS

The rates of integration of the bone plug and femoral bone tunnel on tomosynthesis at 1, 3, and 5 months postoperatively were 0, 55, and 100%, respectively. On the tibial side, the corresponding rates were 0, 75, and 100%, respectively. The rate of integration on the tibial side was significantly higher than that on the femoral side at 3 months postoperatively (p = 0.031).

CONCLUSIONS

Bone-to-bone integration on the femoral and tibial sides was complete within 5 months after surgery in all cases. Since the time required for bone integration is important in designing the postoperative rehabilitation approach, these results will serve as a useful guideline for planning rehabilitation protocols.

LEVEL OF EVIDENCE

IV.

Minimally Invasive Quadriceps Tendon Single-Bundle, Arthroscopic, Anatomic Anterior Cruciate Ligament Reconstruction With Rectangular Bone Tunnels

Many surgeons use quadriceps tendon (QT) graft for anterior cruciate ligament (ACL) revision surgery; however, despite excellent clinical results, the QT has not achieved universal acceptance for primary ACL reconstruction. One of the reasons for this may be that the QT is technically demanding to harvest and the scar from open harvesting techniques is less cosmetically favorable than that from hamstring tendon techniques. Recent evidence has suggested that broad flat QT grafts may more closely mimic native ACL "ribbon-like" morphology than hamstring tendon grafts. Furthermore, rectangular bone tunnels may more accurately re-create native ACL attachments, allowing grafts to simulate native ACL rotation during knee flexion and potentially improving biomechanics. Rectangular tunnels have further advantages in revision cases, in which-in comparison with round tunnels-they have reduced overlap with pre-existing transtibial tunnels, increasing the chance of bypassing primary tunnels during revision surgery. Finally, instrumentation for minimally invasive QT harvesting has reduced technical difficulty and improved cosmetic results. Hence, technical and cosmetic concerns are no longer barriers to QT use. These anatomic and biomechanical advantages and technical developments make the QT an increasingly attractive option for both primary and revision ACL reconstruction.