Comparison of Poly-L-Lactic Acid and Poly-L-Lactic Acid/Hydroxyapatite Bioabsorbable Screws for Tibial Fixation in ACL Reconstruction: Clinical and Magnetic Resonance Imaging Results

BACKGROUND: The purpose of this study was to compare the clinical and radiological results of 2 different tibial fixations performed using bioabsorbable screws with added hydroxyapatite (HA) and pure poly-L-lactic acid (PLLA) screws in anterior cruciate ligament (ACL) reconstruction. METHODS: A total of 394 patients who underwent arthroscopic ACL reconstruction between March 2009 and June 2012 were retrospectively reviewed. Of those, 172 patients who took the radiological and clinical evaluations at more than 2 years after surgery were enrolled and divided into 2 groups: PLLA group (n = 86) and PLLA-HA group (n = 86). Both groups were assessed by means of the Lysholm score, International Knee Documentation Committee (IKDC) subjective knee score, and Tegner activity score. Stability was evaluated using the KT-2000 arthrometer. Magnetic resonance imaging was performed to evaluate tibial tunnel widening, screw resorption, osteoingeration, and foreign body reactions. RESULTS: The PLLA-HA group showed significant reduction in the extent of tibial tunnel widening and foreign body reactions and significant increase in screw resorption compared to the pure PLLA group (p < 0.001 for both). In contrast, postoperative Lysholm score, Tegner activity score, IKDC score, and side-to-side difference on the KT-2000 arthrometer showed no significant differences between groups (p = 0.478, p = 0.906, p = 0.362, and p = 0.078, respectively). The PLLA group showed more significant widening in the proximal tibial tunnel than the PLLA-HA group (p = 0.001). In the correlation analysis, proximal tibial tunnel widening revealed a positive correlation with knee laxity (r = 0.866) and a negative correlation with Lysholm score (r = −0.753) (p < 0.01 for both). CONCLUSIONS: The HA added PLLA screws would be advantageous for tibial graft fixation by reducing tibial tunnel widening, improving osteointegration, and lowering foreign body reactions. Even though no clinically significant differences were noted between the pure PLLA group and PLLA-HA group, widening of the proximal area of the tibial tunnel showed a tendency to increase knee laxity measured using the KT-2000 arthrometer.

The Correlation of Tunnel Position, Orientation and Tunnel Enlargement in Outside-in Single-Bundle Anterior Cruciate Ligament Reconstruction

PURPOSE: Tunnel widening after anterior cruciate ligament (ACL) reconstruction is a frequently described phenomenon. The possible etiology is multi-factorial with some mechanical and biological factors. Among those, we intended to determine the relation between the location and orientation of the femoral tunnel and the femoral tunnel enlargement after outside-in single-bundle ACL reconstruction. MATERIALS AND METHODS: A retrospective study including 42 patients who received single-bundle ACL reconstruction with the outside-in technique was conducted. Femoral and tibial tunnel locations were evaluated with the quadrant method and bird's-eye view using volume-rendering computed tomography. The angle and diameter of bone tunnel and the degree of tunnel enlargement were evaluated using standard radiographs. RESULTS: The degree of femoral tunnel enlargements were 42% and 36% on the anteroposterior (AP) and lateral radiographs, respectively, and the degree of tibial tunnel enlargements were 22% and 23%, respectively. Shallower location of the femoral tunnel was significantly correlated with greater femoral tunnel enlargement on the AP radiograph (r=0.998, p=0.004) and the lateral radiograph (r=0.72, p=0.005) as was the higher location of the femoral tunnel on the AP radiograph (r=-0.47, p=0.01) and the lateral radiograph (r=-0.36, p=0.009) at 12 months after surgery. CONCLUSIONS: This study revealed that more anterior and higher location and more horizontal orientation of the femoral tunnel in coronal plane could result in widening of the femoral tunnel in outside-in single-bundle ACL reconstruction.

Comparison of Tunnel Enlargement between Single and Double Bundle Anterior Cruciate Ligament Reconstruction / 대한정형외과학회잡지

PURPOSE: The aim of this study was to compare the tunnel enlargement in patients who had undergone a double-bundle (DB) or single-bundle (SB) anterior cruciate ligament (ACL) reconstruction, and to determine the correlation between the extent of bone tunnel enlargement and the clinical results. MATERIALS AND METHODS: Among 224 primary ACL reconstructions performed from January 2004 to May 2008 we examined in this study 38 patients who underwent a SB-ACL reconstruction and 30 patients underwent a DB-ACL reconstruction. They were followed up over 1 year. The evaluation methods were the Lachman test, pivot-shift test and KT-1000 measurement for knee stability and the Lysholm score and International Knee Documentation Committee (IKDC) ratings for the functional results. Tunnel enlargement was measured at the sclerotic ridge of the most widest area on the anteroposterior and lateral radiographs in longitudinal and vertical axis of the tunnel. RESULTS: The tunnel enlargement on the femoral side was similar in the DB-ACL group and the SB-ACL group. On the other hand, on the tibial side, the tunnel enlargement was less in the DB-ACL group than in the SB-ACL group (p=0.001, ICC: 0.94). The two groups showed different functional results and extent of stability recovery. The KT-1000 arthrometer revealed 1.1 mm and 93% of negative in the pivot-shift test for the DB-ACL group, which induced an improved tendency compared to the SB-ACL group. No correlation was found between the tunnel enlargement and clinical results. CONCLUSION: A DB-ACL reconstruction results in less tunnel enlargement on the tibial side than a SB-ACL reconstruction. There was no correlation between the tunnel enlargement and clinical results.

Comparative study of femoral tunnel enlargement after hamstring anterior cruciate ligament reconstruction with different graft fixations / 中国矫形外科杂志

[Objective]To compare the changes in femoral bone tunnel after arthroscopically assisted hamstring ACL reconstruction with different graft fixations and investigate the relation with clinical effect.[Method]Eighty-eight cases in three groups were included and underwent hamstring ACL reconstruction with different femoral graft fixations for average 16.5 months follow-up evaluation.Twenty-six cases in group A received Endobutton fixation,twenty-two cases(group B) received interference screw,and forty cases(group C)received Rigidfix system.Femoral bone tunnel diameters at the articular line level,the widest point,1 cm away from tunnel aperture on sagittal MRI were compared at one week postoperatively.Lysholm score was used to evaluate the clinical effect.[Result]Tunnel enlargement after ACL surgery was noted in the three groups.At the femoral widest point and 1 cm away from tunnel aperture,the tunnel enlargement was larger in group B and smaller in group C.At the femoral articular line level,the bone tunnel enlargement in group C was smallest.There was no difference between those of groups A and B.The shape of femoral tunnel was lineal in groups A and C,and conical in group B.No significant difference was found by Lysholm score.[Conclusion]The type of graft fixation is a major factor in the development of tunnel enlargement after ACL surgery.No correlation between graft fixation,bone tunnel enlargement and clinical effect has been found.

Bone Tunnel Enlargement after Endoscopic ACL Reconstruction by Autogenous Bone - Patellar Tendon - Bone Graft / 대한정형외과학회잡지

Radiographic increase in the size of tibial and femoral tunnels has been observed following the reconstruction of the ACL with a bone-patellar tendon-bone autograft. The purpose of this study is to determine if any differences exist in the amount of enlargement of the bone tunnel with the clinical results and to know the factors which affected to the enlargement of the bone tunnels. Total 27 patients were retrospectively reviewed for tunnel enlargement radiographically at one year after operation. Anteroposterior and lateral x-ray were obtained and the tunnel were measured by two independent observers. The measurements were made at the widest part of the tunnel. The distance between tibial interference screw and knee joint line also measured. Correction for magnification was performed by comparing the measured width of the interference screw used for fixation of the graft with its actual width. Statistical analysis was performed with Wilcoxon rank sum test. The radiographic tunnel enlargement was an average of 1.7+/-1.3mm for the femur and 1.9+/-0.8mm for the tibia. The proximal migration of the tibial interference screw was an average of 2.3++/-1.1 mm. There was no statistically significant correlation between the changes in tunnel diameter and either the modified Hughston knee score, Lysholm knee score, or the joint laxity measured by a KT-2000 arthrometer, Lachman test. There were no correlations between the mild proximal migration of the tibial interference screw and the clinical results. Conclusively, the tunnel enlargement and mild proximal migration of the interference screw did not appear to affect the functional outcome adversely. It needs longer follow up for the evaluation of etiology and natural history of this tunnel enlargement.

Enlargement of Tibial Bone Tunnel After Single: Incision Arthroscopically Assisted Reconstruction of Anterior Cruciate Ligaments

After reconstruction of anterior cruciate ligament, increased idameter of femoral or tibia1 bone tunnel has been obsened on plain radiogram. The etiology of radiographic tunnel enlargement is not well understood and the significance of this tunnel enlargement is unknown. This retrospective study reviewed tibial tunnel diameter in 34 cases of anterior cruciate ligament reconstructions. And we evaluated the correlation between the tibial tunnel enlargement and the position of screw fixation, instability, choice of graft, and clinical results at 1 year postoperatively. AII operation was per formed using a single incision technique. After 3 or 4 months and one year after operation, the diameter of tibial tunnel was measured with digital caliper on the plain radiogram. Tibial tunnel sclerotic margins were measured in the level Of medial tibial plateau on the lateral view of knee. Average tunnel enlargement of 3 allografts was 1.62mm and that of 15 autografts was 2.03mm. No significant difference was seen in KT-10000 arthrometer measurements between enlarged group (amount of enlage-ent >+1 S.D) and not-enlarged group (less than +1 S.D). No coelation was present between the increased tunnel diameter and Lysholm score. Cases with 10mm or more vertical distance between the most proximal point of tihial interference screw and the level of m4eial tibial plateau had average 1.15mm tibial tunnel enlargement and cases with less than 10mm vertical distance ha & I average 2.52mm tibial tunne] enlargement;the difference was not significant (P>0.05). The tibial tunnel enlargement was not correlated with position of screw, clinical results, stability of knee. The tibial tunnel enlargement was not caused hy only mechanical factor such as motion of intra-tunnel portion of graft-tendon.

Tibial Tunnel enlargement Following Arthroscopic ACL Reconstruction / 대한정형외과학회잡지

The roentgenograms following arthroscopic ACL reconstruction show the enlargement of bone tunnels. Many authors hypothesized the cause of the tunnel enlargement, either mechanical or biological causes. The purpose of this study was to find the factors which affected the enlargement of the tibial tunnel following arthroscopic ACL reconstruction with bone-patellar tendon-bone or hamstring tendon. Sixty patients were reviewed retrospectively for radiographic measurement of tibial tunnel at post-operative one year (27 patients received bone-patellar tendon-bone autograft, 12 patients received bone-patellar tendon-bone autograft and Kennedy LAD-ligament augmentation device, 21 patients received Semitendinosus and Gracilis tendons with Endobutton). Roentgenographic anteroposterior and lateral films were checked and the tunnel was measured by two independent observers using a digital caliper. Statistical analysis was performed using a one-way analysis of variance (ANOVA) and t-test. The tibial tunnel enlargement was only related to the position of the fixation of the tibial tunnel. We concluded that tibial tunnel enlargement following arthroscopic ACL reconstruction is attributed to the mechanical effect rather than the properties of grafts and the clinical results.