Femoral tunnel enlargement after anatomic anterior cruciate ligament reconstruction: Bone-patellar tendon-bone /single rectangular tunnel versus hamstring tendon / double tunnels

Risk factors of failure results after double-bundle reconstruction with autogenous hamstring grafts for isolated posterior cruciate ligament rupture cases

Posterior tibial translation (PTT) after double-bundle posterior cruciate ligament (PCL) reconstruction has sometimes occurred. Purpose of this study is to identify the risk factors for postoperative PTT after double-bundle PCL reconstruction with a hamstring autograft. Comparing the results of bilateral gravity sag view (GSV) at 12 months after surgery, over 5-mm PTT was defined as 'failure' in this study. Of 26 isolated PCL reconstruction cases, over 5-mm PTT was seen in 7 cases (group F: 9.57 ± 1.28 mm), and 19 cases had less than 5 mm (group G: 2.84 ± 1.29 mm). Age, sex, body mass index (BMI), preoperative GSV, posterior slope angle of the tibia, anterolateral bundle (ALB) and posteromedial bundle (PMB) graft diameters, and tibial tunnel diameter were evaluated. The two groups were compared with the 2 × 2 chi-squared test, the Mann Whitney U-test, and Spearman's rank correlation coefficient. Multivariate logistic regression analysis was also performed to determine the risk factor. Statistical significance was indicated as p < 0.01 for correlation with postoperative PTT, and as p < 0.05 for all other comparisons. Mean age (group G 31.8 ± 12.5 vs group F 34.9 ± 15.9 years), sex (male/female: 15/4 vs 3/4), BMI (25.6 ± 4.6 vs 24.9 ± 3.9 kg/m2), preoperative GSV (11.3 ± 2.2 vs 11.6 ± 2.9 mm), PMB diameter (5.37 ± 0.33 vs 5.36 ± 0.48 mm), and tibial tunnel diameter (9.32 ± 0.58 vs 9.29 ± 0.49 mm) showed no significant differences. ALB diameter was significantly greater in group G (7.0 ± 0.5 mm) than in group F (6.5 ± 0.29 mm; p = 0.022). There was also a significant difference in posterior tibial slope angle (group G 9.19 ± 1.94 vs group F 6.54 ± 1.45, p = 0.004). On Spearman rank correlation coefficient analysis, ALB diameter GSV (correlation coefficient: - 0.561, p = 0.003) and posterior tibial slope angle (correlation coefficient: - 0.533, p = 0.005) showed a significant correlation with postoperative PTT. Multivariate logistic regression analysis showed that ALB diameter (OR 19.028; 95% CI 1.082-334.6; p = 0.044) and posterior slope angle of tibia (OR 3.081; 95% CI 1.109-8.556; p = 0.031) were independently associated with postoperative PTT, respectively. In double-bundle PCL reconstruction with hamstring, smaller ALB graft diameter and lower (flatted) tibial slope angle were considered risk factors for postoperative PTT.

Rectangular-Tunnel Anterior Cruciate Ligament Reconstruction Using Quadriceps Tendon-Patellar Bone Autograft Can Reduce Early Donor Site Morbidity While Maintaining Comparable Short-term Clinical Outcomes

Background

Rectangular tunnel and graft have been recently designed to closely resemble the native anatomy in anterior cruciate ligament reconstruction (ACLR). This study was performed to compare the short-term clinical outcomes between rectangular and round femoral tunnels in ACLR using quadriceps tendon-patellar bone (QTPB) autografts.

Methods

A total of 78 patients who underwent primary ACLR with QTPB autografts performed by three senior surgeons and had at least 1 year of postoperative follow-up were retrospectively reviewed. Patients who underwent rectangular tunnel ACLR (n = 40) were compared to those treated with the conventional round tunnel ACLR (n = 38). Outcomes including knee stability, clinical scores, quadriceps strength, associated complications, postoperative knee range of motion, and cross-sectional area of the graft were assessed.

Results

Significant improvements in knee stability and clinical scores were observed after surgery in both groups (all p < 0.001). The postoperative measurements of knee stability and clinical scores were not significantly different between the two groups. Knee extension strength deficit at 60°/sec was significantly less in the rectangular tunnel group than in the round tunnel group at postoperative 6 months (41.7% vs. 48.9%, p = 0.032). The cross-sectional area of the partial-thickness QTPB graft was approximately 60% of the full-thickness QTPB graft.

Conclusions

In the short-term, rectangular tunnel ACLR was comparable to round tunnel ACLR with QTPB autograft despite the smaller cross-sectional area. Additionally, the rectangular tunnel ACLR allowed partial-thickness grafting technique, which could subsequently reduce early donor site morbidity.

Low Femoral Tunnel Widening Incidence Rate After ACL Reconstruction Using Patellar Tendon Graft with Press-Fit Fixation

Background

Femoral tunnel widening after ACL reconstruction is a common phenomenon. We hypothesized that using a patellar tendon graft with a press-fit fixation technique without any fixation device reduces the incidence of femoral tunnel widening.

Methods

This study was conducted on 467 patients with ACL surgery between 2003 and 2015. Two hundred and nineteen of them had an ACL surgery with patellar tendon (PT) graft, and two hundred and forty-eight of them with hamstring tendon (HS). Exclusion criteria were history of previous ACL reconstruction of either knee, multiple ligament injury, or evidence of osteoarthritis on radiographs. The femoral tunnels were measured on the anteroposterior (ap) and lateral radiographs 6 months after the operation. Two independent orthopedic surgeons measured all radiographs twice and recorded the tunnel widenings. We hypothesized that using an implant-free press-fit technique with PT graft can reduce the femoral tunnel widening incidence rate.

Results

The mean incidence rate of the tunnel widening in the HS group was, on the AP and the lateral femoral views, 88% (n = 217) and 83% (n = 205), while in the PT group, 17% (n = 37) and 2% (n = 4), respectively. There was a significant difference both on AP and lateral radiographs (HS vs. PT: fem. AP: 89% vs. 17% p < 0.001; HS vs. PT: fem. lat: 84% vs. 2% p < 0.001).

Conclusion

The femoral tunnel widening incidence rate during an ACL reconstruction is significantly less when using PT tendon with femoral press-fit fixation than when using HT tendon with suspensory fixation method.

Strategies to promote tendon-bone healing after anterior cruciate ligament reconstruction: Present and future

At present, anterior cruciate ligament (ACL) reconstruction still has a high failure rate. Tendon graft and bone tunnel surface angiogenesis and bony ingrowth are the main physiological processes of tendon-bone healing, and also the main reasons for the postoperative efficacy of ACL reconstruction. Poor tendon-bone healing has been also identified as one of the main causes of unsatisfactory treatment outcomes. The physiological process of tendon-bone healing is complicated because the tendon-bone junction requires the organic fusion of the tendon graft with the bone tissue. The failure of the operation is often caused by tendon dislocation or scar healing. Therefore, it is important to study the possible risk factors for tendon-bone healing and strategies to promote it. This review comprehensively analyzed the risk factors contributing to tendon-bone healing failure after ACL reconstruction. Additionally, we discuss the current strategies used to promote tendon-bone healing following ACL reconstruction.

Anterior Screw Insertion Results in Greater Tibial Tunnel Enlargement Rates after Single-Bundle Anterior Cruciate Ligament Reconstruction than Posterior Insertion: A Retrospective Study

Background and Objectives: Tunnel enlargement (TE) is a widely reported phenomenon after anterior cruciate ligament reconstruction (ACLR). Given the paucity of knowledge in the literature, it remains unclear whether screw position in the tunnel affects TE. This retrospective cohort study evaluated differences in postoperative tunnel enlargement rates (TER) and clinical results between anterior and posterior tibial interference screw insertion during single-bundle ACLR using autologous hamstring grafts. Materials and Methods: A group of consecutive patients that underwent primary arthroscopic single-bundle ACLR in our hospital were screened and divided into two groups based on the position of the tibial interference screw (determined by Computer Tomography within 3 days after surgery): anterior screw position group (A) and posterior screw position group (B). The bone tunnel size was measured using magnetic resonance imaging (MRI) performed 1 year after surgery. International Knee Documentation Committee (IKDC) score and the Knee Injury and Osteoarthritis Outcome Score (KOOS) were used for clinical results 1 year postoperatively. Results: 87 patients were included. The TER of Group A is higher than that of Group B (43.17% vs. 33.80%, p = 0.024). Group A showed a significant increase (12.1%) in enlargement rates at the joint line level than group B (43.77% vs. 31.67%, p = 0.004). Moreover, KOOS and IKDC scores improved in both groups. There were no significant differences in clinical outcomes between the two groups. Conclusions: One year after ACLR, patients with posterior screw showed significantly lower TE than patients with anterior screw. However, the position of screw did not lead to differences in clinical results over our follow-up period. Posterior screw position in the tibial tunnel maybe a better choice in terms of reducing TE. Whether the different screw positions affect the long-term TE and long-term clinical outcomes needs to be confirmed by further studies.

The promotive effect of grafts with the double-stranded peroneus longus tendon and with the four-stranded hamstring tendon on reconstruction of the posterior cruciate ligament injury

INTRODUCTION

Posterior cruciate ligament (PCL) injury hampers the rotational stability and stability front to back of the knee joint, seriously affecting the quality of life of patients. Some studies have reported that the peroneus longus tendon (PLT) has sufficient length and strength.

HYPOTHESIS

We hypothesized that the PLT can be used as a novel appropriate material for PCL reconstruction therapy.

MATERIALS AND METHODS

Herein, we systematically analysed the clinical effect of the double-stranded PLT and the four-stranded hamstring tendon in the reconstruction of the PCL and compared the effectiveness and safety of these two surgical approaches in the reconstruction of PCL injury. A total of 48 patients with complete rupture of the PCL were divided into Group A (reconstructed with the double-stranded PLT, 25 cases) and Group B (reconstructed with the four-stranded hamstring tendon, 23 cases).

RESULTS

The patients were followed up for more than 1 year. The intraoperative time for tendon extraction was significantly shorter in Group A than Group B. Twenty-four months after operation, patients in the two groups showed the alleviated tibial posterior displacement and the increased IKDC score, Lysholm score and Tegner score. Nevertheless, these scores showed no significant differences between the two groups. Additionally, compared with the therapy using the four-stranded hamstring tendon, therapy using the double-stranded PLT is simpler and safer.

DISCUSSION

Both surgical methods are effective in the treatment of PCL injury. The PLT could be a good choice for PCL injury reconstruction material, especially when the four-stranded hamstring tendon is accidentally damaged or ineffective. Our study may provide guidance for the clinical treatment of PCL injury.

LEVEL OF EVIDENCE

III, retrospective study.

No Differences In Clinical Outcomes Between Rectangular and Round Tunnel Techniques For Anterior Crucial Ligament Reconstruction

PURPOSE

To compare the clinical outcomes between conventional round tunnel and rectangular tunnel in anatomic anterior cruciate ligament (ACL) reconstruction.

METHODS

This was a retrospective comparative cohort study between March 2015 and September 2018. The primary ACL reconstructions using anteromedial portal technique with minimum of 2 years follow-up were enrolled for this study. The exclusion criteria were patients with revision ACL reconstruction, high tibial osteotomy, multiligament injuries, and associated fractures around the knee. Outcome measures included the subjective International Knee Documentation Committee score, Tegner activity score, knee laxity testing, and measurement of the centers of the femoral and tibial tunnels on postoperative computed tomography (CT) images.

RESULTS

Forty-seven patients with ACL reconstruction with rectangular tunnel (group 1) and 108 patients with ACL reconstructions with conventional rounded tunnel (group 2) were included consecutively. There were no significant differences between groups in terms of clinical scores or knee laxity, as well as femoral and tibial tunnel positions on CT. One patient in group 2 had ACL failure because of trauma and was treated with revision surgery. Two patients had incomplete tibial fracture, but they healed spontaneously and showed no residual laxity at final follow-up. The intraobserver and interobserver reliability for the radiological measurements ranged from 0.78 to 0.86.

CONCLUSIONS

There were no differences in radiological and clinical results between rectangular tunnel group and conventional round tunnel group for arthroscopic ACL reconstruction. ACL reconstruction with a rectangular tunnel could be considered as a reliable technique, but care should be taken during tunnel establishment because of risk of fractures and malposition of rectangular tunnel.

ACL graft with extra-cortical fixation rotates around the femoral tunnel aperture during knee flexion

PURPOSE

An understanding of the behavior of a new ACL graft in the femoral tunnel during knee motion and external loading can provide information pertinent to graft healing, tunnel enlargement, and graft failure. The purpose of the study was to measure the percentage of the tunnel filled by the graft and determine the amount and location of the graft-tunnel contact with knee motion and under external knee loads.

METHODS

Single bundle anatomical ACL reconstruction was performed on six cadaveric knees. Specimens were positioned with a robotic testing system under: (1) passive flexion-extension, (2) 89-N anterior and posterior tibial loads, (3) 5-N m internal and external torques, and (4) 7-N m valgus moment. The knees were then dissected, repositioned by the robot and the geometry of the femoral tunnel and graft were digitized by laser scanning. The percentage of tunnel filled and the contact region between graft and tunnel at the femoral tunnel aperture were calculated.

RESULTS

The graft occupies approximately 70% of the femoral tunnel aperture and anterior tibial loading tended to reduce this value. The graft contacted about 60% of the tunnel circumference and the location of the graft-tunnel contact changed significantly with knee flexion.

CONCLUSION

This study found that the graft tends to rotate around the tunnel circumference during knee flexion-extension and contract under knee loading. The "windshield-wiper" and "bungee cord" effect may contribute to femoral tunnel enlargement, affect graft healing, and lead to graft failure. There can be a considerable motion of the graft in the tunnel after surgery and appropriate rehabilitation time should be allowed for graft-tunnel healing to occur. To reduce graft motion, consideration should be given to interference screw fixation or a graft with bone blocks, which may allow an earlier return to activity.

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.

Tunnel Enlargement Correlates With Postoperative Posterior Laxity After Double-Bundle Posterior Cruciate Ligament Reconstruction

Background:

There exists little information in the relevant literature regarding tunnel enlargement after posterior cruciate ligament (PCL) reconstruction (PCLR).

Purpose:

To sequentially evaluate tunnel enlargement and radiographic posterior laxity through double-bundle PCLR using autologous hamstring tendon grafts.

Study Design:

Case series; Level of evidence, 4.

Methods:

We prospectively analyzed 13 patients who underwent double-bundle PCLR for an isolated PCL injury. Three-dimensional computed tomography images were obtained at 3 weeks, 6 months, and 1 year postoperatively, and the tunnel enlargement was calculated by sequentially comparing the cross-sectional areas of the bone tunnels. We also sequentially measured radiographic posterior laxity. The correlation between the tunnel enlargement ratio and the postoperative increase in posterior laxity was evaluated.

Results:

The cross-sectional area at the aperture in each tunnel significantly increased from 3 weeks to 6 months (P < .003), but it did not continue doing so thereafter. The 6-month tunnel enlargement ratios of the femoral anterolateral tunnel, the femoral posteromedial tunnel, the tibial anterolateral tunnel, and the tibial posteromedial tunnel were 31.6% ± 23.5%, 90.3% ± 54.7%, 30.5% ± 26.8%, and 49.6% ± 37.0%, respectively, while the corresponding ratios at 1 year were 28.1% ± 19.8%, 83.1% ± 56.9%, 26.8% ± 32.8%, and 47.6% ± 39.0%, respectively. The posterior laxity was 9.0 ± 4.0 mm, −1.5 ± 2.3 mm, 3.4 ± 2.0 mm, and 3.9 ± 1.9 mm, preoperatively, immediately after surgery, 6 months and 1 year postoperatively, respectively. From the immediate postoperative period, the posterior laxity significantly increased at 6 months postoperatively (P < .001), but it did not thereafter. The postoperative increase in posterior laxity had a significant positive correlation with the anterolateral tunnel enlargement ratio in both femoral and tibial tunnels at 6 months (ρ = 0.571-0.699; P = .011-.041) and 1 year (ρ = 0.582-0.615; P = .033-.037).

Conclusion:

Tunnel enlargement after PCLR mainly occurred within 6 months, with no progression thereafter. The anterolateral tunnel enlargement positively correlated with postoperative increase in posterior laxity.

Biological Augmentation of ACL Repair and Reconstruction: Current Status and Future Perspective

Historically, anterior cruciate ligament (ACL) suture repair mostly resulted in failure because of intra-articular hypovascularity and poor intrinsic healing capacity of ACL. ACL reconstruction was therefore deemed the gold standard with a high success rate because of more evolved surgical technique. There are, however, clinical and subclinical disadvantages of reconstruction; low rate in full recovery to sports, donor harvest morbidity, tunnel enlargement, and incomplete microscopic healing of the graft. Recent experimental and clinical studies on biological augmentation of mesenchymal stem cells, platelet-rich plasma, or the other biologic agents with scaffold suggested potential feasibility of positive effects by such bio-therapies for both ACL repair and reconstruction. Biological augmentation of ACL surgery is still in the exploratory stages and more evidence from preclinical and clinical studies is required for implementation in clinical practice.

Bioabsorbable interference screws can be used with less tunnel widening in anatomic rectangular tunnel anterior cruciate ligament reconstruction with a bone-patellar-tendon-bone graft

BACKGROUND

The purpose of this study was to investigate postoperative tunnel widening after rectangular tunnel bone-patellar-tendon-bone graft anterior cruciate ligament reconstruction using newer-generation bioabsorbable interference screws.

METHODS

Forty-six patients who had undergone primary rectangular tunnel bone-patellar-tendon-bone graft anterior cruciate ligament reconstruction using MILAGRO bioabsorbable interference screws (DePuy Synthes, Warsaw, IN, USA) for femoral fixation and for whom computed tomography was performed at two weeks and one year postoperatively were included in this prospective study. To assess the tunnel widening, the cross-sectional area of the femoral tunnel aperture (compared between two weeks and one year postoperatively) was assessed using computed tomography. Cyst formation, postoperative screw breakage, screw migration, and graft migration were also evaluated using computed tomography one year postoperatively.

RESULTS

Mean tunnel widening was 1.9%, and the cross-sectional area of the femoral tunnel aperture was not significantly different between two weeks and one year postoperatively. Postoperative cyst formation, screw breakage, screw migration, and graft migration were not observed in any patient.

CONCLUSIONS

After rectangular tunnel bone-patellar-tendon-bone graft anterior cruciate ligament reconstruction using bioabsorbable interference screws for femoral fixation, tunnel widening was not observed via computed tomography analysis at two weeks and one year postoperatively.

A more flattened bone tunnel has a positive effect on tendon-bone healing in the early period after ACL reconstruction

PURPOSE

The purpose of this study was to evaluate whether a flattened bone tunnel has a positive effect on the tendon-bone healing (TBH) process in the early period after anterior cruciate ligament (ACL) reconstruction.

METHODS

Seventy-two New Zealand White rabbits were randomly allocated into two groups, the flattened tunnel (FT) group and the conventional round tunnel (RT) group. We compared the cross-sectional areas and diameters of the bone tunnels between the two groups through computed tomography (CT) scanning. TBH results between the two groups were assessed by histological analysis, micro-CT scanning and biomechanical tests at 4 weeks, 8 weeks and 12 weeks after operation.

RESULTS

The cross-sectional areas of the bone tunnels between the two groups were almost the same. However, the shape of bone tunnels in the FT group was more flattened. A faster cellular and collagen remoulding process were found in the FT group. Semiquantitative histological analysis of Safranin O staining showed that there was more fibrocartilage formation in the interface region in the FT group (P < 0.05). Sirius Red staining showed that the tissues in the interface areas were more intense in the FT group. Micro-CT scanning showed that more new bone formation could be found in the interface region in the FT group. The biomechanical tests also showed that FT ACL reconstruction will result in a stronger regenerated tendon-bone interface.

CONCLUSIONS

Our study found that a flattened bone tunnel accelerated TBH in the early period after ACL reconstruction surgery in a rabbit model, which lays the groundwork for further clinical practice of this ACL reconstruction method.