Background:
Clinical utility of remnant tissue preservation after single-bundle anterior cruciate ligament (ACL) reconstruction has not been established. In addition, no studies have evaluated the ...clinical utility of remnant preservation after anatomic double-bundle ACL reconstruction.
Hypothesis:
The study hypotheses were as follows: (1) Subjective and functional clinical results may be comparable between anatomic double-bundle reconstructions that preserve the remnant tissue and those that resect the remnant tissue, (2) postoperative knee stability and the second-look arthroscopic evaluation may be significantly more favorable with the remnant-preserving reconstruction, and (3) the degree of the initial graft coverage may significantly affect postoperative knee stability.
Study Design:
Cohort study; Level of evidence, 2.
Methods:
A total of 179 patients underwent anatomic double-bundle ACL reconstruction. Based on the Crain classification of ACL remnant tissue, 81 patients underwent the remnant-preserving procedure (group P) and the remaining 98 patients underwent the remnant-resecting procedure (group R). There were no differences between the 2 groups concerning all background factors, including preoperative knee instability and intraoperative tunnel positions. The patients were followed for 2 years or more.
Results:
The subjective and functional clinical results were comparable between the 2 reconstruction procedures. Side-to-side anterior laxity was significantly less (P = .0277) in group P (0.9 mm) than in group R (1.5 mm). The pivot-shift test was negative in 89% of group P and 78% of group R patients; the result for group R was significantly lower (P = .0460). In the arthroscopic observations, results for group P were significantly better than for group R concerning postoperative laceration and fibrous tissue coverage of the grafts (P = .0479).
Conclusion:
Remnant preservation in anatomic double-bundle ACL reconstruction did not significantly improve subjective and functional results in the short-term evaluation, but it significantly improved postoperative knee stability. The degree of initial graft coverage significantly affected postoperative knee stability.
Background: Several trials have been conducted to compare the clinical results between anatomic double-bundle and single-bundle anterior
cruciate ligament (ACL) reconstruction procedures. In these ...studies, however, the number of patients was insufficient to compare
the clinical results of the 2 procedures.
Hypothesis: The anatomic double-bundle procedure may be significantly better concerning the anterior laxity and the pivot-shift test
than the single-bundle procedure, while there may be no significant differences in the other clinical evaluations and the
intra-operative and postoperative complications between the 2 procedures.
Study Design: Cohort study; Level of evidence, 2.
Methods: Three hundred and twenty-eight patients with unilateral ACL reconstruction using hamstring autografts were divided into 2
groups. The first 157 consecutive patients underwent single-bundle reconstruction and the remaining 171 patients underwent
anatomic double-bundle reconstruction. Concerning all background factors, there were no statistical differences between the
2 groups. Each patient was examined 2 years after surgery.
Results: No serious complications were experienced in either group. The anterior laxity was significantly less in the double-bundle
reconstruction (mean, 1.2 mm) than in the single-bundle reconstruction (mean, 2.5 mm). In the pivot-shift test, the double
bundle (+ indication, 16%; ++, 3%) was significantly better than the single bundle (+ result, 37%; ++, 12%). The mean Lysholm
score averaged 96.5 points and 97.3 points in single-bundle and double-bundle reconstructions, respectively, while the International
Knee Documentation Committee evaluation showed that 90 and 110 patients, respectively, were evaluated as rank A (no significant
difference between groups). There were no significant differences in the other clinical evaluations and the complications
between the 2 procedures.
Conclusions: The postoperative anterior and rotational stability after the anatomic double-bundle ACL reconstruction was significantly
better than that after the single-bundle reconstruction, although there were no significant differences between the 2 procedures
concerning the complications and the clinical evaluations.
Keywords:
anterior cruciate ligament
anatomic double-bundle reconstruction
hamstring tendon autograft
posterolateral bundle
clinical outcome
Abstract Soft supporting tissues in the human body, such as cartilages and ligaments, are tough materials firmly fixed to bones. These soft tissues, once injured, cannot regenerate spontaneously in ...vivo . Developing tough and biocompatible hydrogels as artificial soft supporting tissues would substantially improve outcomes after soft tissue injury. Collagen is the main rigid component in soft connective tissues which is organized in various hierarchical arrays. We have successfully developed a novel class of collagen fibril-based tough hydrogels based on the double network concept using swim bladder collagen (SBC) extracted from Bester sturgeon fish. The DN hydrogels, SBC/PDMAAm, are composed of physically/chemically crosslinked anisotropic SBC fibril as the first network and neutral biocompatible poly(N,N′-dimethylacrylamide) (PDMAAm) as the second network. The anisotropic structure of SBC fibril, which is well retained in the DN hydrogels, is formed by free injection method, taking advantage of the excellent fibrillogenesis capacity of SBC. The denaturation temperature of collagen is improved in the DN hydrogels. These DN gels possess anisotropic swelling behavior, exhibiting excellent mechanical properties comparable to natural cartilage. The 4 weeks implantation of the gels in the osteochondral defect of rabbit knee also shows excellent biomechanical performance in vivo . Furthermore, the hydroxyapatite (HAp) coated DN gels, HAp/SBC/PDMAAm gels, strongly bond to bone after 4 weeks. This new class of collagen-based hybrid DN gels, as soft and elastic ceramics, having good biomechanical performance and strong bonding ability with bone would expand the choice for designing next-generation orthopedic implants such as artificial cartilage, bone defect repair material in the load-bearing region in the body.
Purpose The purpose was to clarify the load-bearing functions of the fibers of the femoral anterior cruciate ligament (ACL) attachment in resisting tibial anterior drawer and rotation. Methods A ...sequential cutting study was performed on 8 fresh-frozen human knees. The femoral attachment of the ACL was divided into a central area that had dense fibers inserting directly into the femur and anterior and posterior fan-like extension areas. The ACL fibers were cut sequentially from the bone: the posterior fan-like area in 2 stages, the central dense area in 4 stages, and then the anterior fan-like area in 2 stages. Each knee was mounted in a robotic joint testing system that applied tibial anteroposterior 6-mm translations and 10° or 15° of internal rotation at 0° to 90° of flexion. The reduction of restraining force or moment was measured after each cut. Results The central area resisted 82% to 90% of the anterior drawer force; the anterior fan-like area, 2% to 3%; and the posterior fan-like area, 11% to 15%. Among the 4 central areas, most load was carried close to the roof of the intercondylar notch: the anteromedial bundle resisted 66% to 84% of the force and the posterolateral bundle resisted 16% to 9% from 0° to 90° of flexion. There was no clear pattern for tibial internal rotation, with the load shared among the posterodistal and central areas near extension and mostly the central areas in flexion. Conclusions Under the experimental conditions described, 66% to 84% of the resistance to tibial anterior drawer arose from the ACL fibers at the central-proximal area of the femoral attachment, corresponding to the anteromedial bundle; the fan-like extension fibers contributed very little. This work did not support moving a single-bundle ACL graft to the side wall of the notch or attempting to cover the whole attachment area if the intention was to mimic how the natural ACL resists tibial displacements. Clinical Relevance There is ongoing debate about how best to reconstruct the ACL to restore normal knee function, including where is the best place for ACL graft tunnels. This study found that the most important area on the femur, in terms of resisting displacement of the tibia, was in the central-anterior part of the femoral ACL attachment, near the roof of the intercondylar notch. The testing protocol did not lead to data that would support using a large ACL graft tunnel that attempts to cover the whole natural femoral attachment area.
Based on the molecular stent concept, a series of tough double‐network hydrogels (St‐DN gels) made from the components of proteoglycan aggregates – chondroitin sulfate proteoglycans (1), chondroitin ...sulfate (2), and sodium hyaluronate (3) – are successfully developed in combination with a neutral biocompatible polymer. This work demonstrates a promising method to create biopolymer‐based tough hydrogels for biomedical applications.
Background: Although both anatomic double-bundle and single-bundle anterior cruciate ligament reconstruction procedures are in use, it remains controversial whether the anatomic double-bundle ...procedure is biomechanically superior.
Hypothesis: The anatomic double-bundle procedure would be better than both laterally placed anatomic and nonanatomic transtibial single-bundle procedures at restoring to normal the tibial anterior translation, internal rotation, and pivot-shift instability. It was also hypothesized that tibial internal rotation would be closer to normal after laterally placed anatomic single-bundle reconstruction than after the nonanatomic reconstruction.
Study Design: Controlled laboratory study.
Methods: Eight cadaveric knees were mounted in a 6 degrees of freedom rig and tested using the following loading conditions: 90-N anterior and posterior tibial forces, 5-N·m internal and external tibial rotation torques, and a simulated pivot-shift test. Tibiofemoral kinematics during the flexion-extension cycle were recorded with an optical tracking system for (1) intact, (2) anterior cruciate ligament–deficient knee, (3) anatomic double-bundle reconstruction, (4) nonanatomic single-bundle reconstruction, and (5) laterally placed single-bundle reconstruction.
Results: Rotational laxity with internal tibial torque and anterior laxity in the simulated pivot shift were significantly less in the double-bundle reconstruction and laterally placed single-bundle reconstruction compared with the nonanatomic single-bundle reconstruction. There were no significant differences between the 3 procedures when anterior and posterior tibial translation forces and external rotation torques were applied. In addition, there were no significant differences between the double-bundle reconstruction and laterally placed single-bundle reconstruction.
Conclusion: The postoperative rotational and pivot-shift laxity after anatomic double-bundle anterior cruciate ligament reconstruction was significantly better than that after nonanatomic single-bundle reconstruction. However, there were no significant differences between the double-bundle reconstruction and laterally placed single-bundle reconstruction.
Clinical Relevance: This work suggests that a single-bundle reconstruction may be better able to control both knee laxity and pivot-shift instability if the femoral tunnel is moved to a more lateral position and that then the double-bundle reconstruction may not offer significant further advantages.
Background:Fractional flow reserve (FFR) is widely used for the assessment of myocardial ischemia. Intravascular ultrasound (IVUS) is an intracoronary imaging method that provides information about ...lumen and vessel morphology. Previous studies on the expanded use of IVUS to identify functional ischemia have noted an association between anatomy and physiology, but IVUS-derived minimum lumen area (MLA) has a weak-moderate correlation with myocardial ischemia compared with FFR. We developed a method to calculate FFR using IVUS-derived anatomical information for the assessment of myocardial ischemia. The aims of this study were to investigate the relationship between wire-based FFR and IVUS-derived FFR (IVUS-FFR) and to compare the usefulness of IVUS-FFR and IVUS-derived MLA for functional assessment.Methods and Results:We retrospectively analyzed 50 lesions in 48 patients with coronary stenosis who underwent IVUS and FFR simultaneously. IVUS-FFR was calculated using our original algorithm and fluid dynamics. Mean percent diameter stenosis determined on quantitative coronary angiography and on FFR was 56.4±10.7 and 0.69±0.08, respectively. IVUS-FFR had a stronger linear correlation with FFR (R=0.78, P<0.001; root mean square error, 0.057 FFR units) than with IVUS-derived MLA (R=0.43, P=0.002).Conclusions:IVUS-FFR may be a more valuable method to identify myocardial ischemia, compared with IVUS-derived MLA.
Background:
Outcomes and complications at mid- or long-term follow-up after medial open-wedge high tibial osteotomy (MOWHTO) with the TomoFix locking plate have not been fully evaluated.
Purpose:
To ...evaluate the complications and midterm clinical outcomes after MOWHTO using a TomoFix.
Study Design:
Case series; Level of evidence, 4.
Methods:
Enrolled in this study were 80 patients (85 knees) who underwent MOWHTO with the TomoFix locking plate between 2009 and 2013. There were 66 women and 14 men, with a mean age of 61.5 years at the time of surgery. The diagnosis was medial osteoarthritis in 76 knees and spontaneous osteonecrosis of the knee in 9 knees. Metal removal and second-look arthroscopy were performed in all cases. Clinical and radiological examinations were performed at final follow-up after surgery (mean, 4.5 years).
Results:
The mean Japanese Orthopaedic Association score and Knee injury and Osteoarthritis Outcome Score improved significantly from pre- to postoperatively (P < .0001). The weightbearing line percentage shifted to pass through a point 67.7% lateral from the medial edge of the tibial plateau. The Caton-Deschamps index changed significantly from 0.88 to 0.66 at final follow-up (P < .0001). The mean posterior tibial slope changed significantly from 8.9° to 11.9° at final follow-up (P < .0001). Limb length was significantly increased after MOWHTO (10.3 mm; P < .0001). During plate removal, 14 locking screws were found to be broken in 9 knees (10.6%). The articular cartilage grade of the patellofemoral joint was significantly higher in the second arthroscopy than in the first arthroscopy (P < .0001). The cumulative rate of all complications was 41.2%, with major complications (ie, those requiring additional or extended treatment) in 24.7%.
Conclusion:
Postoperative outcome scores indicated significant improvement after MOWHTO, although the cumulative rate of all complications was 41.2% and the rate of major complications was 24.7%. These results indicate that MOWHTO with the TomoFix is a technically demanding procedure. Careful preoperative planning and meticulous surgical technique are needed to decrease the incidence of complications associated with MOWHTO.
Purpose: To compare the clinical outcome of anatomic double-bundle anterior cruciate ligament (ACL) reconstruction with that of nonanatomic single- and double-bundle reconstructions.
Type of Study: ...Prospective comparative cohort study.
Methods: Seventy-two patients with unilateral ACL-deficient knees were randomly divided into 3 groups. Concerning all background factors, there were no statistical differences among the 3 groups. In group S (n = 24), single-bundle ACL reconstruction was performed. In group N-AD (n = 24), nonanatomic double-bundle reconstruction was carried out. In group AD (n = 24), anatomic double-bundle reconstruction was performed. One surgeon performed all operations using hamstring tendon autografts. Each patient underwent clinical examinations, before surgery and at 2 years.
Results: No intraoperative and postoperative complications were experienced in each group. There were no significant differences concerning the time for operation among the 3 groups. The statistical analysis showed a significant difference in the postoperative side-to-side anterior laxity among the 3 groups (
P = .006). The laxity was significantly less (
P = .002) in group AD (1.1 mm) than in group S (2.8 mm), while there was no significant difference (
P = .072) between groups AD and N-AD. Concerning the pivot-shift test, group AD was significantly superior to group S (
P = .025). There were no significant differences in the range of knee motion, the muscle torque, and the International Knee Documentation Committee evaluation.
Conclusions: On the basis of the KT-2000 measurement, the side-to-side anterior laxity of our anatomic double-bundle ACL reconstruction was significantly better than that of the single-bundle reconstruction with the hamstring tendon graft, although there were no significant differences in the other clinical measures among any of the 3 procedures.
Level of Evidence: Level II.
Abstract Background An ideal synthetic spacer for medial opening wedge high tibial osteotomy (MOWHTO) has not yet been developed. The authors have developed a new β-tricalcium phosphate (β-TCP) ...spacer with 60% porosity (N-CP60) by modifying the micro- and macro-pore structures of a conventional β-TCP spacer (CP60) that is widely used in clinical practice. The purpose of this study was to compare the absorbability, osteoconductivity, and in vivo strength of the N-CP60 spacer with those of the CP60 spacer, when used in MOWHTO. Methods First, the porosity, diameter distribution of macro- and micropores, and compressive strength of each β-TCP block were examined using methodology of biomaterial science. Secondly, a clinical study was performed using a total of 106 patients (106 knees) with MOWHTO, who were followed up for 18 months after surgery. In these knees, the N-CP60 and CP-60 spacers were implanted into 49 tibias and 57 tibias, respectively. The absorbability and osteoconductivity were radiologically evaluated by measuring the area of the implanted spacer remaining unabsorbed and assessing with the Hemert’s score, respectively. The incidence of cracking in the implanted spacers was determined using computed radiography. Statistical comparisons were made with non-parametric tests. The significance level was set at p = 0.05. Results The N-CP60 and CP60 blocks had almost the same porosity (mean, 61.0% and 58.7%, respectively). The diameter of macropores was significantly larger ( p < 0.0001) in the N-CP60 block than in the CP60 block, while the diameter of micropores was significantly smaller ( p = 0.019) in the N-CP60 block. The ultimate strength of the N-CP60 block (median, 36.8 MPa) was significantly greater ( p < 0.01) than that of the CP60 block (31.6 MPa). As for the clinical evaluations, the absorption rate of the N-CP60 spacer at 18 months after implantation (mean, 48.0%) was significantly greater ( p < 0.001) than that of the CP60 spacer (29.0%). The osteoconductivity of the N-CP60 spacer was slightly but significantly higher ( p = 0.0408) than that of the CP60 spacer only in zone 1. The incidence of in vivo cracking of the posteriorly located N-CP60 spacer at one month (mean, 75.5%) was significantly lower ( p = 0.0035) than that of the CP60 spacer (91.2%). Conclusions The absorbability, osteoconductivity, and compressive strength of the new N-CP60 spacer were significantly improved by modifying the macro- and micro-pore structures, compared with the conventional CP60 spacer. The N-CP60 spacer is more clinically useful than the CP60 spacer. Trial registration number H29-0002.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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