The Influence of Bone Bruises on Bone Tunnel Enlargement Regarding ACL Rupture

Purpose: The purpose was to determine the impact of the size of bone bruises (BBs) on bone tunnel enlargement (BTE) occurrence. Materials and methods: Twenty-four (24) patients who underwent anterior cruciate ligament reconstruction (ACLR) were included in this retrospective study. The measurements of BBs based on the initial MRI scan, bone tunnel size based on the control MRI scan, and the spatial determination of BB in relation to the bone tunnel location were evaluated. To analyze the relationship between BBs and BTE in homogeneous groups regarding the time from injury to ACLR (t(I-S)), the largest subgroup B (n = 15), in which t(I-S) was 31 to 60 days, was isolated for further investigation. Results: Based on subgroup B, a weak correlation (r = 0.33) existed between the BB volume and BTE size in the femur and tibia. Considering the relationship between the distance from the BB to the bone tunnel in the femur (f-l) and its enlargement (Δfd), there was a moderate and statistically significant (p < 0.05) negative correlation (r = −0.64). The correlation between those parameters was even stronger (r = −0.77) in subgroup B (time interval between injury and surgery ranged from 31 to 60 days). Conclusions: A retrospective analysis of MRI data in patients after ACL reconstruction surgery showed a relevant association between the distance from the BB to the bone tunnel and BTE in the femur. The relationship was not confirmed in the tibia.

Clinical study of anatomical ACL reconstruction using a rounded rectangular dilator

Background The aim of this study was that to compare clinical results between the rounded rectangular femoral tunnel ACL reconstruction (RFTR) and the conventional round femoral tunnel ACL reconstruction using a hamstring tendon. The hypothesis was that ACL reconstruction performed using the rounded rectangular dilator technique was better than that performed using the conventional round femoral tunnel technique in terms of clinical results and bone tunnel enlargement. Methods We conducted retrospective study. After exclusions, 40 patients were included in the conventional anatomical single-bundle ACL reconstruction (ASBR) group and 40 patients were included in the RFTR group. The evaluation items were knee stability, Lysholm knee score, IKDC subjective score at 2 years after surgery and bone tunnel enlargement. Results The RFTR group had a larger femoral tunnel area (average area, 53.1 ± 4.0 mm2 vs. 46.1 ± 7.0 mm2; P < 0.01), better anteroposterior stability, and higher Lysholm scores than the ASBR group (average side-to-side difference for anterior tibial translation, 0.6 ± 0.8 mm vs. 1.6 ± 1.4 mm; P < 0.01; average Lysholm score, 98.5 ± 2.1 vs. 97.5 ± 3.5; P < 0.01). Further, bone tunnel enlargement ratio was significantly lower in the RFTR group (73 ± 38% vs. 107 ± 41%; P < 0.01). Conclusions We designed and developed an original rounded rectangular dilator to perform a novel ACL surgery. This technique can create a larger bone tunnel and improve clinical results than the conventional round anatomical single-bundle ACL reconstruction.

Biomechanical Modeling of a Bone Tunnel Enlargement Post ACL Reconstruction

BackgroundBone tunnel enlargement is considered as a potential problem following ACL reconstruction and can cause a fixation failure and complicate its revision surgery. This study evaluates post tibial tunnel expansion in ACL reconstruction using an interference screw.MethodsA series of in-vitro experimental tests on animal bone and tissues were used to simulate post ACL reconstruction. The study believes an unbalanced lateral force can cause a local enlargement on the contact zone inside the tunnel. Grayscale X-ray images were used to assess the screw alignment inside the tunnel.ResultsThey showed a slight misalignment between the screw and the tunnel axis as the tendon strands moved along the side of the tunnel, and the screw had partial contact with the tendon and bone along the tunnel. According to the results, increased stress in the tunnel wall causes tunnel enlargement. Although the tunnel created away from the tibial central axis produced a higher strength, it results in higher stress on the wall of the tunnel which can increase the risk of tunnel expansion.ConclusionsThe current study believes the use of an unguided interference screw insertion potentially increases risks of the misaligned fixation and cause a tunnel enlargement. This risk may be controlled by restricting the post-operative rehabilitation.

Clinical and Radiographic Outcomes of Double-Bundle Anterior Cruciate Ligament Reconstruction for Asian Patients with Bone-Patellar Tendon-Bone and Gracilis Tendon Grafts: A Matched-Control Comparison

For anterior cruciate ligament (ACL)-deficient patients, using a single bone-patellar tendon-bone (BPTB) graft for the double-bundle concept is one of the suitable approaches for acquiring better stability and reducing bone tunnel enlargement compared with the use of hamstring grafts. At least 10-mm width of BPTB autograft is needed to achieve this concept; however, it is larger than one-third of the patellar tendon width for small or middle physique patients. This study aimed to assess the clinical and radiographic outcomes of BPTB and gracilis (G) composite autografts for primary double-bundle ACL reconstruction in Asian athletes. Thirty-two Asian patients undergoing double-bundle ACL reconstruction with 7.0 to 7.5 mm of BPTB and 5.0 to 5.5 mm of G composite grafts were compared with 43 double-bundle ACL reconstruction with hamstring graft cases. The BPTB graft was used for the anteromedial bundle (AMB), with the G graft for the posterolateral bundle (PLB). Percentage of femoral bone tunnel enlargement compared with the original size was determined by computed digital radiographs on the first postoperative day and at 12 months in the anteroposterior (AP) and lateral views. Standard clinical evaluations, including the limb symmetry index (LSI), were also performed. Less PLB tunnel enlargement was found in the BPTB + G group than in the hamstring group in the AP (101.9 ± 22.9 vs.113.7 ± 20.6%, p = 0.031) and lateral views (104.4 ± 18.1 vs. 120.6 ± 23.4%, p < 0.01).There was no significant difference between the groups in 12-month postoperative clinical outcomes (Lysholm's score, Tegner's activity level scale, and International Knee Documentation Committee subjective knee evaluation score).The side-to-side difference was significantly less in the BPTB + G group (0.2 ± 1.3 vs. 0.9 ± 1.1 mm, p = 0.026). Despite the small sizes of the BPTB and G grafts, there was no significant difference in the knee extensor LSI between the groups (92.9 ± 10.1 vs. 93.3 ± 12.2%, p = 0.707), whereas the knee flexor LSI was significantly higher in the BPTB + G group (97.7 ± 14.8 vs. 90.1 ± 13.3%, p = 0.033). Double-bundle ACL reconstruction with a small size BPTB and G composite graft procedure provided good clinical outcomes and significantly less femoral bone tunnel enlargement than the hamstring procedure 12 months after surgery. It is thus a useful surgical option for ACL-deficient Asian athletes. This study reflects level of evidence III.

BONE TUNNEL ENLARGEMENT WITH NON-METALLIC INTERFERENCE SCREWS IN ACL RECONSTRUCTION

ABSTRACT Objective: To compare the widening of bone tunnels between poly-etheretherketone (PEEK), absorbable polylactic acid DL (PLDL) and tricalcium phosphate (TCP) interference screws in anterior cruciate ligament (ACL) reconstruction. Methods: Three groups of patients undergoing ACL reconstruction with at least 1 year of follow-up using the out-in drilling technique and hamstring as a graft were assessed. The patients were divided according to the type of interference screw used (PEEK, PLDL and TCP). Computed tomography (CT) was performed to measure the greatest femoral and tibial tunnel widening regarding to the initial tunnel, and then it was compared between groups. Results: Mean widening in group 1 (PEEK) was 39.56% (SD 16%) in the femoral tunnel and 33.65% (SD 20%) in the tibia. In group 2 (PLDL) mean widening was 48.43% in the femoral tunnel (SD 18%) and 35.24% (SD 13%) in the tibial tunnel. In group 3 (TCP) mean widening was 44.51% in the femur (SD 14%) and 36.83% in the tibia (SD 14%). The comparison between groups (PLDL-PEEK, PLDL-TCP, PEEK-TCP) shows no statistically significant difference. Conclusion: Bone tunnel enlargement values after ACL reconstruction with the use of different types of materials (bioinert and biomaterials) of interference screws (PEEK, PLDL and TCP) were similar. Level of Evidence III, Comparative retrospective study.