Graft Laceration Research Articles

The experience of use of percutaneous transhepatic biliary drainages for early biliary complications after liver transplantation.

This study aimed to describe our experience and discuss the results, controversies, and the use of percutaneous transhepatic biliary drainage (PTBD) in patients with biliary complications after liver transplantation (LT). Between November 2009 and August 2020, 76 consecutive patients who underwent 77 LTs (44 deceased donor LTs and 33 living donor LTs [LDLT]) were enrolled retrospectively. Endoscopic therapy as initial approach and PTBD as rescue therapy were used for patients with biliary complications. There were 31 patients (31/76, 40.8%) with biliary complications, and two of them died (2/31, 6.5%). Clinical success rate of endoscopic therapy alone was 71.0% (22/31). The remaining nine patients received salvage PTBD and their clinical results were observed according to whether their intrahepatic bile ducts (IHBDs) was dilated (group A, n=5) or not (group B, n=4). In group A, the technical and long-term clinical success rates of PTBD were 100% and 20%, respectively. These five patients received PTBD ranging from 75 to 732 days after their LTs, and no procedure-related complications were encountered. In group B, the technical and long-term clinical success rates of PTBD were 50% and 25%, respectively. Three group B patients (75%) underwent PTBD within 30 days after LDLT and had lethal complications. One patient had graft laceration and survived after receiving timely re-transplantation. The other two patients died of sepsis due to PTBD-related bilioportal fistula or multiple liver abscesses. Our experience showed salvage PTBD played a limited role in biliary complications without dilated IHBDs within 1 month after LT.

Whether sutures reduce the graft laceration caused by interference screw in anterior cruciate ligament reconstruction? A biomechanical study in vitro

BackgroundInterference screw is commonly used for graft fixation in anterior cruciate ligament (ACL) reconstruction. However, previous studies had reported that the insertion of interference screws significantly caused graft laceration. The purposes of this study were to (1) quantitatively evaluate the graft laceration from one single insertion of PEEK interference screws; and (2) determine whether different types of sutures reduced the graft laceration after one single insertion of interference screws in ACL reconstruction.MethodsThe in-vitro ACL reconstruction model was created using porcine tibias and bovine extensor digitorum tendons of bovine hind limbs. The ends of grafts were sutured using three different sutures, including the bioabsorbable, Ethibond and ultra-high molecular weight polyethylene (UHMWPE) sutures. Poly-ether-ether-ketone (PEEK) interference screws were used for tibial fixation. This study was divided into five groups (n = 10 in each group): the non-fixed group, the non-sutured group, the absorbable suture group, the Ethibond suture group and the UHMWPE suture group. Biomechanical tests were performed using the mode of pull-to-failure loading tests at 10 mm/min. Tensile stiffness (newtons per millimeter), energy absorbed to failure (in joules) and ultimate load (newtons) were recorded for analysis.ResultsAll prepared tendons and bone specimens showed similar characteristics (length, weight, and pre-tension of the tendons, tibial bone mineral density) among all groups (P > 0.05). The biomechanical tests demonstrated that PEEK interference screws significantly caused the graft laceration (P < 0.05). However, all sutures (the bioabsorbable, Ethibond and UHMWPE sutures) did not reduce the graft laceration in ACL reconstruction (P > 0.05).ConclusionsOur biomechanical study suggested that the ultimate failure load of grafts was reduced of approximately 25 % after one single insertion of a PEEK interference screw in ACL reconstruction. Suturing the ends of the grafts using different sutures (absorbable, Ethibond and UHMWPE sutures) did not decrease the graft laceration caused by interference screws.

Clinical complications of biodegradable screws for ligament injuries.

Anterior cruciate ligament (ACL) plays a crucial role stabilizing the knee joint while connecting tibia to femur. Lack of proper treatment of injured ACL can lead to meniscus tear and osteoarthritis. Interference screws secure the graft tissue for superior integration of graft on host tissue during autograft fixation. Metal interference screws come with various disadvantages like mechanical load mismatch, graft laceration, secondary surgical removal and hindrance during MRI and CT post-operative scan. Though biodegradable polymeric screws provide various advantages their clinical outcomes reveal unprecedented complications for long term use of such screws. This review highlights polymer and composite screw currently available for surgical fixations and associated adverse reactions with the proposed mechanism for tunnel enlargement, effusion, osteolysis in ligament repairs. The need for suitable material engineering for development of orthopedic screws for successful rigid fixation has been highlighted in this review.

Clinical Outcomes After Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction: Comparison of Extreme Knee Hyperextension and Normal to Mild Knee Hyperextension

The aim of this study was to compare postoperative outcomes after anatomic double-bundle anterior cruciate ligament reconstruction (ACLR) in extreme knee hyperextension versus normal to mild knee hyperextension. For 100 patients who underwent anatomic double-bundle ACLR using semitendinosus tendon, we evaluated the side-to-side difference (SSD) in anterior tibial translation (measured on stress radiographs) and rotational stability (assessed by the pivot-shift test) 2 years after surgery. Loss of extension (LOE) was evaluated on lateral radiographs of both knees in full extension, and graft integrity was assessed during second-look arthroscopy 1 to 2 years after surgery. In accordance with the Beighton and Honan criteria, patients with an extension angle less than or equal to 10° in the contralateral uninjured knee composed the group with 10° or less hyperextension (N group), and those with an extension angle of greater than 10° composed the group with more than 10° hyperextension (H group). Postoperative results were compared between these groups. Mean extension angles in the N and H groups were 5.8° ± 2.9° and 14.7° ± 3.0°, respectively. The mean SSD in anterior translation was 2.2 ± 2.9 mm for the N group and 2.8 ± 2.9 mm for the H group, with no significant difference. The positive ratios on the pivot-shift test were not significantly different between the groups. Mean LOE in the N and H groups was-0.7° ± 3.7° and 1.3° ± 3.3°, respectively, with a significant difference (P= .007). During second-look arthroscopy, 6 of 58 knees in the N group and 13 of 42 knees in the H group had superficial graft laceration of the anteromedial bundle graft, with a significant difference (P= .01) seen between groups. Anatomic double-bundle ACLR for extreme knee hyperextension may attain the same postoperative anterior and rotational stability as seen in knees with normal to mild hyperextension. However, it increased superficial graft laceration. Level III, retrospective comparative study.

The Importance of Tibial Tunnel Placement in Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction

The purposes of this study were to measure the anterior edge of the tibial tunnel after anatomic anterior cruciate ligament (ACL) reconstruction on lateral radiographs and to determine whether the difference in tibial tunnel placement affects postoperative outcomes. For 60 patients who underwent anatomic double-bundle ACL reconstruction with semitendinosus tendon, we evaluated the side-to-side difference in anterior tibial translation on stress radiographs, as well as rotational stability by the pivot-shift test, 2 years after surgery. Loss of extension (LOE) was evaluated on lateral radiographs of both knees in full extension, and graft integrity was assessed during second-look arthroscopy 1 to 2 years after surgery. On true lateral radiographs, we measured the anterior placement percentage of the tibial tunnel using the method described by Amis and Jakob. The cutoff value was set at 25% of the mean value of the anterior edge of the ACL that Amis and Jakob reported, and patients were divided into 2 groups (27 in the anterior group and 33 in the posterior group). Postoperative clinical results were compared between the groups. The mean anterior placement percentage was 26.0% ± 4.1%. The postoperative mean side-to-side difference was 1.4 ± 2.7 mm for the anterior group and 3.0 ± 2.7 mm for the posterior group, a significant difference (P < .05). The positive ratio of the pivot-shift test was not significantly different between groups (P > .05). Mean LOE in the anterior and posterior groups was 0.9° ± 3.0° and -0.8° ± 4.0°, respectively; the difference was not significant (P > .05). Five of 27 knees in the anterior group and 5 of 33 knees in the posterior group had superficial graft laceration or elongation, which was not significantly different (P > .05). Anterior placement of the tibial tunnel in anatomic double-bundle ACL reconstruction leads to better anterior knee stability than posterior placement does. Anterior tibial tunnel placement inside the footprint did not increase the incidence of LOE and graft failure. Level IV, therapeutic case series.

Effect of Interference Screw Fixation on ACL Graft Tensile Strength

Tibial-sided fixation of soft tissue grafts in anterior cruciate ligament (ACL) reconstruction has often been identified as the weak link in the fixation construct, with interference screws being a commonly used technique. A significant concern surrounding the use of interference screws for soft tissue fixation is graft laceration and the possibility of loss of pull-out strength and slippage. The act of interference screw insertion for soft tissue graft fixation in ACL reconstruction alters the biomechanical properties of the graft. Two groups of 12 porcine knees (24 total) were utilized for the tibial-sided fixation of porcine flexor digitorum tendons using single-insertion interference screws, in a model of soft tissue ACL reconstruction. Two different screw types were used for comparison. Following screw insertion, the grafts were dissected free and underwent biomechanical testing in tension to failure. Control flexor digitorum tendons underwent the same biomechanical testing for comparison. Control soft tissue grafts exhibited significantly higher yield load, ultimate load, and stiffness (p < 0.001) in comparison to both groups of treated grafts, without evidence of significant macroscopic damage. Single insertion of interference screws for soft tissue graft fixation in ACL reconstruction weakens the biomechanical properties of the graft itself.

Arthroscopic anterior cruciate ligament reconstruction with modified “wireless” cross-screw transfix femoral fixation

Among several graft fixation options in arthroscopic ACL reconstruction for hamstring tendons, transcondylar fixation has been suggested to offer mechanical advantages compared to other femoral fixation systems. Blind nature of the procedure may result in several complications including iliotibial band irritation syndrome, breakage of the bio absorbable cross-pin, stress fracture of the femoral cortex, and more commonly intraoperative wire loop twisting, resulting in fixation failure, wire breakage or graft laceration. We used "wireless" transfixation technique to avoid complications associated with wire loop.

The Biomechanical Performance of Bone Block and Soft-Tissue Posterior Cruciate Ligament Graft Fixation With Interference Screw and Cross-Pin Techniques

The purpose of this study was to evaluate the biomechanical properties of 4 different graft fixation constructs on the tibial side of the posterior cruciate ligament with reconstruction by use of an Achilles tendon graft. Biomechanical testing of 4 different fixation techniques was performed on 20 human cadaveric tibias and Achilles tendons. Cross-pin fixation with bone blocks (group A), interference screw fixation with bone blocks (group B), cross-pin fixation of soft tissue with backup fixation (group C), and interference screw fixation of soft tissue with backup fixation (group D) were tested. The tibia-graft fixation complex was cyclically loaded between 50 N and 250 N at 1 Hz for 1,000 cycles. After cycling, the amount of graft displacement was determined by measuring the change in grip-to-grip distance. The complex was then loaded to failure at 1 mm/s, and maximum failure load, stiffness, and mode of failure were determined. Group C had a higher maximum failure load and stiffness than groups A and B (P < .05 and P < .001, respectively) but poor results for displacement (P < .05 and P < .05, respectively). The failure modes were bone block fracture, graft laceration, or cross-pin fracture in the cross-pin groups and graft pullout in the interference screw groups. Our study suggests that maximum failure load and stiffness of hybrid fixation for Achilles tendon graft are comparable to those of both single calcaneal bone plug fixation methods that we studied. However, tendon graft displacement was significantly greater regardless of fixation method when compared with bone plug fixation. Hybrid fixation for soft-tissue graft on the tibial fixation site provides comparable biomechanical properties of bone-to-bone fixation.

Extra-Articular Extraosseous Migration of a Bioabsorbable Femoral Interference Screw After ACL Reconstruction

Anterior cruciate ligament (ACL) reconstruction is quite commonly used to treat anterior knee instability. Surgeon preference and patient functional goals determine graft selection and graft fixation techniques. Interference screws are considered a safe and effective device for graft fixation in surgical ACL reconstruction. Poly-L-lactide acid (PLLA) bioabsorbable interference screws are becoming increasingly popular in ACL reconstruction surgery. There are several reasons why they may be more advantageous than metallic screws, including reduced graft laceration during insertion, ease of performance of revision procedures, avoidance of graft injury encountered with aperture fixation using metallic screws, and fewer artifacts on magnetic resonance images (MRI). Few studies describe complications associated with PLLA bioabsorbable screws, particularly extra-articular screw migration. This article presents a case of an extra-articular extraosseous migration of the femoral bioabsorbable interference screw. This case further demonstrates the problem of the femoral bioabsorbable interference screw.

Graft Laceration and Pullout Strength of Soft-Tissue Anterior Cruciate Ligament Reconstruction: In Vitro Study Comparing Titanium, Poly-D,L-Lactide, and Poly-D,L-Lactide–Tricalcium Phosphate Screws

The aim of part 1 of this study was to compare the structural properties of tibia-graft-interference screw constructs of soft-tissue graft fixation via the anterior cruciate ligament (ACL) by use of different interference screws. In part 2 the influence of graft laceration as a result of 1 single interference screw insertion on the mechanical properties of the graft was evaluated. In part 1 of the study, in a bovine knee model, soft-tissue graft fixation with titanium, biodegradable poly-D,L-lactide (PLDLA), and PLDLA-tricalcium phosphate (TCP) interference screws was performed, and the structural properties were determined by use of a materials testing machine at a rate of 12.5 mm/s. In part 2 the bone was cut after 1 single insertion of titanium, PLDLA, or PLDLA-TCP interference screws, and the mechanical properties of the graft were determined. Soft-tissue graft fixation with a biodegradable PLDLA interference screw showed a statistically significantly higher maximum load when compared with PLDLA-TCP and titanium interference screws. PLDLA-TCP screw fixation revealed a significantly higher ultimate load than titanium screw fixation. The mechanical properties of the grafts after 1 single insertion of PLDLA-TCP interference screws showed a statistically significantly higher stiffness, yield load, and maximum load when compared with the PLDLA and titanium interference screw groups. The results of this study suggest that the use of a titanium screw to fix a soft-tissue graft in cruciate ligament reconstruction surgery may cause damage to the graft. Soft-tissue ACL reconstruction fixed with a PLDLA interference screw resulted in a significantly higher pullout strength than ACL reconstructions fixed with a PLDLA-TCP or titanium interference screw. In contrast to fixation with a biodegradable interference screw, fixation with a titanium interference screw may damage the integrity of a soft-tissue graft in cruciate ligament reconstruction and should therefore be avoided.

Initial fixation strength of a new hybrid technique for femoral ACL graft fixation: the bone wedge technique

Aperture fixation with interference screws matching the diameter of the tunnel is associated with the risk of graft laceration and graft rotation. A hybrid fixation technique (extracortical and aperture fixation) with undersized interference screw placed behind a bone wedge provides a higher fixation strength as aperture fixation with a screw alone matching the size of the tunnel. Experimental laboratory study. We evaluated the initial fixation strength (single cycle and cyclic loading tests) of hybrid and interference screw aperture fixation using different sized interference screws in porcine knees. Analysis of yield load, maximum load and stiffness in the single cycle loading test showed no statistically significant differences for hybrid fixation with a 1 mm undersized screw and aperture fixation with a screw matching the size of the tunnel. The use of an undersized screw alone resulted in low fixation strength. The initial fixation strength of the hybrid technique with undersized screws is comparable to that of interference screw fixation matching the size. The new "bone wedge fixation" is an alternative for ACL graft fixation without the risk of graft laceration and graft rotation.

Initial fixation strength of a hybrid technique for femoral ACL graft fixation

Aperture fixation with interference screws matching the diameter of the tunnel is associated with the risk of graft laceration and graft rotation. A hybrid fixation technique (extracortical and aperture fixation) with undersized interference screws provides a higher fixation strength when compared to an aperture fixation using only a screw matching the size of the tunnel and also reduces the risk of graft laceration. This research is an experimental laboratory study. We evaluated the initial fixation strength at time-zero of an extracortical-, a hybrid- and an aperture fixation in ACL reconstruction using extracortical buttons and different sized interference screws in porcine knees. The tests were performed using a single cycle and cyclic loading protocol. Analysis of yield load, maximum load and stiffness in the single cycle loading test showed no statistically significant differences for hybrid fixation with a 1 mm undersized screw and aperture fixation with a screw matching the size of the tunnel. Cyclic loading tests showed a statistically significant difference between hybrid and aperture fixation. The use of an undersized screw alone in aperture fixation resulted in insufficient fixation strength. The initial fixation strength of the hybrid technique with undersized screws is higher compared to an interference screw fixation alone. The hybrid fixation technique is an alternative for ACL graft fixation.

Soft-Tissue Interference Fixation: Bioabsorbable Screw Versus Metal Screw

To compare the biomechanical properties of eccentrically positioned bioabsorbable and titanium interference screws for quadrupled hamstring tendon graft (QHTG) fixation. In vitro, biomechanical study. In 10 paired cadaveric tibiae and femurs (mean age, 66.5 years; range, 53 to 81 years), QHTG fixation was performed in tunnels sized to within 0.5 mm of QHTG diameter using either a titanium (RCI; Smith & Nephew Donjoy, Carlsbad, CA) or a bioabsorbable (BioScrew; Linvatec, Largo, FL) screw of equal size. Constructs then underwent biomechanical load-to-failure testing on a servo-hydraulic device at 20 mm/min. Load at failure was greater for femoral-side QHTG fixation using the bioabsorbable screw than the titanium screw (486 +/- 223.7 N v 246 +/- 99.1 N, P = .006); however, displacement did not differ (P = .81). There were no statistically significant differences between groups for tibial side load at failure (P = .54), stiffness (P = .44), or displacement (P = .50). Screw thread-induced graft laceration was more frequently observed in the titanium screw group (9 of 10 grafts during femoral-side testing, 0 of 10 grafts during tibial-side testing) than in the bioabsorbable screw group (0 of 10 grafts during femoral-side testing, 1 of 10 grafts during tibial-side testing). BioScrew interference screw fixation was comparable or superior to RCI titanium interference screw fixation. BioScrew interference screw fixation also produced less screw thread-induced laceration of the QHTG during load-to-failure testing. Use of a biodegradable interference screw positioned directly against a soft-tissue graft provides fixation properties similar to those of a metal interference screw.

Protection of the bone-tendon-bone graft during anterior cruciate ligament reconstruction

Damage of graft fibers is a complication that can happen during arthroscopic reconstruction of the anterior cruciate ligament. It usually occurs while pulling the neoligament through the tibial tunnel, inserting the femoral screw, or doing additional notchplasty. Protection of the graft with a polyethylene tube can reduce the risk of graft laceration.

Endoscopic anterior cruciate ligament reconstruction: modified technique and radiographic review.

The original technique for endoscopic anterior cruciate ligament reconstruction has several potential complications because of constraints imposed by working through the tibial tunnel: improper femoral tunnel placement, violation of the femoral tunnel posterior wall, femoral interference screw divergence, graft laceration during screw insertion, and distal tibial bone block protrusion. We performed 100 consecutive endoscopic anterior cruciate ligament reconstructions with bone-tendon-bone autograft using a modified technique that minimizes each of these problems through the use of an accessory medial parapatellar portal. Postoperative radiographic review showed femoral screw divergence in only 9% of cases (average angle, 6.9 degrees), all in the anteroposterior plane. The tibial tunnel was drilled at an average of 66 degrees to the plateau and averaged 52 mm in length. There was no graft damage during screw insertion or protrusion of the bone blocks. We conclude that this modified technique allows simplified, reproducible tunnel and interference screw placement.