Is Prophylactic Antibiotic Use Necessary Before Dental Procedures in Primary and Revision TKA? A Propensity Score-matched, Large-database Study.

BACKGROUND: The question of whether dental procedures increase the risk of periprosthetic joint infection (PJI) in patients who have undergone total joint arthroplasty (TJA) remains controversial. QUESTIONS/PURPOSES: (1) Are dental procedures associated with an increased incidence of PJI in the setting of either primary or revision TKA after controlling for relevant potentially confounding variables? (2) Is the administration of prophylactic antibiotics before dental procedures associated with any differences in this risk? (3) Which factors are associated with increased incidence of PJI after dental procedures? METHODS: This nationwide, retrospective, comparative, large-database study evaluated 591,602 patients who underwent unilateral primary or revision TKA between 2009 and 2019 using the Health Insurance Review and Assessment Service data in South Korea, in which all people in South Korea were registered and to which all medical institutions must charge any procedures they performed. The study population was divided into 530,156 patients with dental procedures and 61,446 patients without dental procedures based on whether the patients underwent a dental procedure at least 1 year after the index surgery. After propensity score matching, patients were classified into a dental (n = 182,052) and a nondental cohort (n = 61,422). The dental cohort was then divided into two groups: 66,303 patients with prophylactic antibiotics and 115,749 patients without prophylactic antibiotics based on prophylactic antibiotic use. After propensity score matching, patients were categorized into prophylactic (n = 66,277) and nonprophylactic (n = 66,277) cohorts. Propensity score matching was used to control for covariates including posttraumatic arthritis associated with PJI risk according to the dental procedure and prophylactic antibiotic use among the cohorts. After propensity score matching, the standardized mean difference was confirmed to be less than 0.1 for all variables. Kaplan-Meier survival analyses, log-rank tests, and Cox proportional hazards regression analysis was performed. RESULTS: Dental procedures were not associated with an increase in PJI risk after primary (adjusted HR 1.56 [95% CI 0.30 to 8.15]; p = 0.60) or revision TKA (adjusted HR 1.74 [95% CI 0.90 to 3.34]; p = 0.10). Additionally, use of prophylactic antibiotics was not associated with a reduced PJI risk after the index surgery, either for primary (adjusted HR 1.28 [95% CI 0.30 to 5.42]; p = 0.74) or revision TKA (adjusted HR 0.74 [95% CI 0.45 to 1.23]; p = 0.25). Although surgery type and prophylactic antibiotic use exhibited no influence on PJI occurrence after dental procedures, posttraumatic arthritis was associated with PJI. The adjusted HR for posttraumatic arthritis was 4.54 (p = 0.046). CONCLUSION: Our findings suggest that dental procedures were not associated with an increased risk of PJI for up to 2 years after the dental procedure in patients who underwent either primary or revision TKA. Based on these findings, there is insufficient rationale for the use of prophylactic antibiotics before dental procedures in patients who have undergone primary or revision TKA. LEVEL OF EVIDENCE: Level III, therapeutic study.

Therapeutic Nanodiamonds Containing Icariin Ameliorate the Progression of Osteoarthritis in Rats.

In present study, icariin (ICA)/tannic acid (TA)-nanodiamonds (NDs) were prepared as follows. ICA was anchored to ND surfaces with absorbed TA (ICA/TA-NDs) and we evaluated their in vitro anti-inflammatory effects on lipopolysaccharide (LPS)-activated macrophages and in vivo cartilage protective effects on a rat model of monosodium iodoacetate (MIA)-induced osteoarthritis (OA). The ICA/TA-NDs showed prolonged release of ICA from the NDs for up to 28 days in a sustained manner. ICA/TA-NDs inhibited the mRNA levels of pro-inflammatory elements, including matrix metalloproteinases-3 (MMP-3), cyclooxygenase-2 (COX-2), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α), and increased the mRNA levels of anti-inflammatory factors (i.e., IL-4 and IL-10) in LPS-activated RAW 264.7 macrophages. Animal studies exhibited that intra-articular injection of ICA/TA-NDs notably suppressed levels of IL-6, MMP-3, and TNF-α and induced level of IL-10 in serum of MIA-induced OA rat models in a dose-dependent manner. Furthermore, these noticeable anti-inflammatory effects of ICA/TA-NDs remarkably contributed to the protection of the progression of MIA-induced OA and cartilage degradation, as exhibited by micro-computed tomography (micro-CT), gross findings, and histological investigations. Accordingly, in vitro and in vivo findings suggest that the prolonged ICA delivery of ICA/TA-NDs possesses an excellent latent to improve inflammation as well as defend against cartilage disorder in OA.

In Vitro Anti-Inflammatory and Antioxidant Activities of pH-Responsive Resveratrol-Urocanic Acid Nano-Assemblies.

Inflammatory environments provide vital biochemical stimuli (i.e., oxidative stress, pH, and enzymes) for triggered drug delivery in a controlled manner. Inflammation alters the local pH within the affected tissues. As a result, pH-sensitive nanomaterials can be used to effectively target drugs to the site of inflammation. Herein, we designed pH-sensitive nanoparticles in which resveratrol (an anti-inflammatory and antioxidant compound (RES)) and urocanic acid (UA) were complexed with a pH-sensitive moiety using an emulsion method. These RES-UA NPs were characterized by transmission electron microscopy, dynamic light scattering, zeta potential, and FT-IR spectroscopy. The anti-inflammatory and antioxidant activities of the RES-UA NPs were assessed in RAW 264.7 macrophages. The NPs were circular in shape and ranged in size from 106 to 180 nm. The RES-UA NPs suppressed the mRNA expression of the pro-inflammatory molecules inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), interleukin-1ß (IL-1ß), and tumor necrosis factor-α (TNF-α) in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages in a concentration-dependent manner. Incubation of LPS-stimulated macrophages with RES-UA NPs reduced the generation of reactive oxygen species (ROS) in a concentration-dependent manner. These results suggest that pH-responsive RES-UA NPs can be used to decrease ROS generation and inflammation.

Hip-to-calcaneus alignment differs from hip-to-talus alignment in patients with genu varum deformity.

PURPOSE: To (1) compare the weight-bearing line (WBL) ratios of the knee joints measured using the conventional (hip-to-talus radiographs, HTRs) and novel (hip-to-calcaneus radiographs, HCRs) orthoradiograms, (2) compare the hip-knee-ankle (HKA) angle between cases with < 5% and > 5% differences in WBL ratios between two orthoradiograms, and (3) investigate the optimal cutoff value (COV) of the HKA angle causing inconsistency in the orthoradiograms. METHODS: Sixty limbs of 31 patients with HTR and HCR records were retrospectively reviewed. After drawing the mechanical axis on each radiograph, the WBL ratios of the knees were calculated and compared between the conventional and novel orthoradiograms. In subgroup analysis, cases with < 5% and > 5% differences in WBL ratios between two orthoradiograms were classified as consistent and inconsistent groups, respectively. Receiver operating characteristic curve based on the HKA angles of the lower limbs was used to identify the COV causing the inconsistency between the orthoradiograms. RESULTS: Inter- and intra-rater reliabilities of all radiologic measurements were > 0.75. The WBL ratios showed no significant difference between the two orthoradiograms. However, the HKA angle was significantly larger in the inconsistent group than in the consistent group (7.0° ± 1.8° vs. 4.4° ± 2.5°; P < 0.001). The COV of the HKA angle that caused inconsistency in the two orthoradiograms was 4.0° (area under the curve, 0.774). CONCLUSION: The hip-to-calcaneus alignment differed significantly from the hip-to-talus alignment in patients with genu varum deformity. HCR measurement can be a complementary method for planning corrective osteotomy for patients with genu varum deformity. LEVEL OF EVIDENCE: IV.

Change in the weight-bearing line ratio of the ankle joint and ankle joint line orientation after knee arthroplasty and high tibial osteotomy in patients with genu varum deformity.

PURPOSE: Several studies reported that excessive correction of severe genu varum deformity with total knee arthroplasty or high tibial osteotomy (HTO) could result in ankle joint pain and osteoarthritis progression. However, few studies have evaluated the change in the weight-bearing-line (WBL) ratio of the ankle joint after knee arthroplasty or HTO in patients with genu varum deformities. This study aimed to investigate the change in the WBL ratio of the ankle joint and ankle joint line orientation after knee arthroplasty or HTO in patients with genu varum deformities. METHODS: We retrospectively evaluated 40 patients (mean age, 69.9 ± 8.0 years) with genu varum deformities of > 5° and underwent knee arthroplasty or HTO. Three radiologic parameters, including (1) the hip-knee-ankle (HKA) angle, (2) WBL ratio of the ankle joint, and (3) ankle joint line orientation relative to the ground (AJLO-G), were assessed using pre-operative and post-operative orthoradiographs. A paired t test was used to evaluate post-operative changes in the three parameters. Correlations between the change in HKA angle and that in the WBL ratio of the ankle joint and AJLO-G were analyzed. RESULTS: The mean HKA angle significantly decreased post-operatively (10.6° ± 5.3° to 1.1° ± 3.4°; P < 0.001). The WBL ratio of the ankle joint increased from 35.8% ± 15.2% to 53.0% ± 17.4% (P < 0.001), with a lateral shift of the mechanical axis. The AJLO-G decreased with valgization of ankle orientation (7.8° ± 4.8° to 0.4° ± 3.8°; P < 0.001). The change in the HKA angle was significantly correlated with that in the AJLO-G (correlation coefficient = 0.716; P < 0.001) but not with the change in the WBL ratio of the ankle joint. CONCLUSION: Knee arthroplasty and HTO corrected the genu varum deformity, which influenced the lateral shift of the WBL of the ankle joint and valgization of the ankle joint line orientation.

Epidemiology of Bearing Dislocations After Mobile-Bearing Unicompartmental Knee Arthroplasty: Multicenter Analysis of 67 Bearing Dislocations.

BACKGROUND: This study investigated the epidemiology and causes of bearing dislocations following mobile-bearing unicompartmental knee arthroplasty (MUKA) and determined whether the incidence of primary bearing dislocations decreases as surgeon experience increases. METHODS: We retrospectively reviewed the bearing dislocations following MUKAs performed by 14 surgeons with variable experience levels. Causes of bearing dislocations were determined based on the surgical records, radiographs, and operator's suggestion. Using a chi-squared test, the incidence of bearing dislocation was compared between the first 50, the second 50, and the next 100 unicompartmental knee arthroplasties (UKAs) of each surgeon's cohort. RESULTS: There were 67 (3.6%) bearing dislocations from 1853 MUKAs. The mean time to bearing dislocations after index MUKAs was 33 months (range, 1-144 months); 55% of the bearing dislocations occurred within 2 years after the index MUKAs. Primary bearing dislocations (n = 58) were the most common, followed by secondary (n = 6) and traumatic dislocations (n = 3). There was no significant difference in the incidence of bearing dislocation between the first 50 and second 50 UKAs for each surgeon. Two surgeons showed a significant decrease in bearing dislocations in their second 100 UKAs, while the other surgeons did not show a difference between their first 100 and second 100 UKAs. CONCLUSION: Most bearing dislocations after MUKAs were related to technical errors such as component malposition or gap imbalance. This study did not confirm that the incidence of bearing dislocations decreases as the number of cases increases. LEVEL OF EVIDENCE: IV, Case series.

Editorial Commentary: Lateral Hinge Fracture After Opening Wedge High Tibial Osteotomy With Long Locking Plate Use.

Lateral hinge fracture (LHF) is a common complication after opening wedge high tibial osteotomy. Such a fracture can be caused by many factors such as osteotomy level, amount of opening, hinge position, and kind of plate. In particular, long locking plates have superior biomechanical stability in cases of LHF compared with short plates. Therefore, these long locking plates should be used in cases of LHF after opening wedge high tibial osteotomy.

A Retrospective Comparison of Union Rates After Open Wedge High Tibial Osteotomies With and Without Synthetic Bone Grafts (Hydroxyapatite and ß-tricalciumphosphate) at 2 Years.

PURPOSE: To evaluate the clinical and radiological results of no bone graft (NBG) after opening wedge high tibial osteotomy (OWHTO) with a locking plate and to compare the bone union rate between the synthetic bone graft (SBG) group and the NBG group after OWHTO using serial radiographs. METHODS: From 2012 to 2015, OWHTOs were performed with SBG or without bone graft using long locking plates. Inclusion criteria were: (1) OWHTO for disease of the medial compartment with varus deformity, and (2) minimum 2-year follow-up and radiographs taken serially to 2 years. Exclusion criteria were: (1) follow-up period <2 years (n = 8) or (2) absence of at least 1 radiograph taken at each follow-up point (n = 14). We retrospectively reviewed radiographs taken preoperatively and at 6 weeks, 3 months, 6 months, 1 year, and 2 years postoperatively. Groups comprised those filled with a synthetic bone [hydroxyapatite (HA) and ß-tricalciumphosphate (TCP), n=33, SBG group] or without a bone graft (n = 38, NBG group). We compared bone union rate between the 2 groups by measuring the union zone from zone 1 to zone 5 in serial radiographs using Fisher's exact test. RESULTS: OWHTO was performed in a total of 93 knees and 71 knees were included in this study. Both groups showed good clinical and radiological results without correction loss at 2 years. The entire NBG group and 93.9% of the SBG group showed union over zone 3 at 2 years. However, the NBG group showed significantly more incorporation than the SBG group at 6 months (P = .006), 1 year (P = .0003), and 2 years (P = .0003). CONCLUSIONS: Union without correction loss was obtained after OWHTO without bone graft. The NBG group showed significantly more incorporation than the SBG group (HA and ß-TCP) within 2 years. LEVEL OF EVIDENCE: Level IV, case series.

Hamstring autograft maturation is superior to tibialis allograft following anatomic single-bundle anterior cruciate ligament reconstruction.

PURPOSE: Using second-look arthroscopy, graft maturation was investigated and compared between hamstring (HA) autografts and tibialis anterior (TA) allografts after anatomic single-bundle anterior cruciate ligament reconstruction (ACLR). METHODS: Fifty-six patients who underwent second-look arthroscopy after anatomic single-bundle ACLR with either HA autografts (26, HA group) or TA allografts (30, TA group) from 2007 to 2016 were retrospectively reviewed. Graft maturation on second-look arthroscopy was evaluated in terms of four parameters: graft integrity (tear), synovial coverage, graft tension, and graft vascularization. Each parameter received a maximum of two points, depending on the status of the reconstructed graft. The total graft maturation score was calculated as the sum of the parameter scores. The total graft maturation and individual parameter scores were compared between the two groups. RESULTS: The mean time from ACLR to second-look arthroscopy was 22.5 ± 7.8 months. The maturation scores in the HA group were significantly better in terms of graft integrity (p = 0.041), graft tension (p = 0.010), and graft vascularization (p = 0.024), whereas the graft synovial coverage score was not significantly different. The total graft maturation score of the HA group was significantly higher than that of the TA group (6.3 ± 0.4 vs. 4.9 ± 0.3, p = 0.013). CONCLUSIONS: This study shows the superior graft maturation of HA autografts compared with that of TA allografts at a mean follow-up of 22.5 ± 7.8 months after anatomic single-bundle ACLR. When anatomic ACLR using soft tissue graft is planned, HA autograft is recommended rather than soft tissue allograft, especially in young and active patients. LEVEL OF EVIDENCE: Retrospective cohort review, Level III.

Sagittal osteotomy inclination in medial open-wedge high tibial osteotomy.

PURPOSE: Unlike postoperative changes in posterior tibial slope after medial open-wedge high tibial osteotomy, sagittal osteotomy inclination has not been examined. It has been recommended that the osteotomy line in the sagittal plane be parallel to the medial posterior tibial slope. The purpose of this study was to determine the frequency of parallel osteotomy in medial open-wedge high tibial osteotomy. METHODS: To determine the sagittal osteotomy inclination, the angle between the medial joint line and the osteotomy line was measured in the lateral radiograph. A positive angle value indicates that the osteotomy is anteriorly inclined relative to the medial posterior tibial slope. Correlation between the sagittal osteotomy inclination and posterior tibial slope was also evaluated. RESULTS: The mean sagittal osteotomy inclination was 15.1 ± 7.5°. The majority 87.1 % of knees showed an anterior-inclined osteotomy. There was a significantly positive correlation between the postoperative posterior tibial slope and the sagittal osteotomy inclination (r, 0.33; 95 % confidence interval (CI) 0.19-0.46; P < 0.001). The postoperative change in posterior tibial slope also showed a significantly positive correlation with the sagittal osteotomy inclination (r, 0.35; 95 % CI 0.21-0.47; P < 0.001). CONCLUSION: Although parallel osteotomy in the sagittal plane relative to the medial joint line was planned, only 12.9 % of cases achieved osteotomy parallel to the medial posterior tibial slope in the sagittal plane. Because of high rate of the anterior-inclined osteotomy and their correlations with posterior tibial slope, surgeons should make all efforts to perform parallel osteotomy relative to medial posterior tibial slope. LEVEL OF EVIDENCE: IV.

Diagnostic Value of Synovial White Blood Cell Count and Serum C-Reactive Protein for Acute Periprosthetic Joint Infection After Knee Arthroplasty.

BACKGROUND: The diagnosis of periprosthetic joint infection (PJI) remains difficult, particularly in acute postoperative stage. The purpose of this study was to investigate the optimal cutoff value of synovial white blood cell (WBC) count, percentage of polymorphonuclear cells, erythrocyte sedimentation rate, and C-reactive protein (CRP) for diagnosing early postoperative infection after knee joint arthroplasty. METHODS: We retrospectively reviewed primary total knee arthroplasties and unicompartmental knee arthroplasties, with a knee aspiration within 3 weeks of surgery, from January 2006 to November 2016. Twelve infected cases and 185 uninfected cases met the inclusion criteria of our study. We compared the laboratory parameters (synovial WBC count, percentage of polymorphonuclear cells, erythrocyte sedimentation rate, and CRP levels) between the 2 groups. Receiver operating characteristic curves were constructed to determine the optimal cutoff values for each parameter. Each parameter was studied to determine its sensitivity, specificity, and positive and negative predictive values (PPV and NPV) in diagnosing acute PJI. RESULTS: There were 2 optimal cutoff values for synovial WBC count and CRP levels. With the cutoff value of synovial WBC set at 11,200 cells/µL, acute PJI could be diagnosed with the highest sensitivity (100%) and specificity (98.9%); with the cutoff value set at 16,000 cells/µL, the best PPV and NPV were found (100% and 99.5%, respectively). Similarly, the CRP level >34.9 mg/L had the best sensitivity (100%) and specificity (90.3%), whereas the CRP level >74.5 mg/L had the best PPV (100%) and NPV (99.2%). CONCLUSION: Synovial WBC count and CRP levels are useful in diagnosing acute PJI between 1 and 3 weeks after primary knee arthroplasty.

Comparison of femoral tunnel geometry, using in vivo 3-dimensional computed tomography, during transportal and outside-in single-bundle anterior cruciate ligament reconstruction techniques.

PURPOSE: To compare the transportal (TP) and outside-in (OI) techniques regarding femoral tunnel position and geometry after anatomic single-bundle (SB) anterior cruciate ligament (ACL) reconstruction. METHODS: This study included 51 patients who underwent anatomic SB ACL reconstruction with the TP (n = 21) or OI (n = 30) technique. All patients underwent 3-dimensional computed tomography 3 days after the operation. The femoral tunnel position (quadrant method), femoral graft bending angle, femoral tunnel length, and posterior wall breakage were assessed by immediate postoperative 3-dimensional computed tomography with OsiriX imaging software. RESULTS: The OI technique had a shallower femoral tunnel position (arthroscopic position) than did the TP technique (P = .005). The mean femoral graft bending angle was significantly more acute with the OI technique (101.3° ± 8.2°) than with the TP technique (107.9° ± 10.0°) (P = .02). The mean femoral tunnel length was significantly greater with the OI technique (33.0 ± 3.5 mm) than with the TP technique (29.6 ± 3.9 mm) (P = .003). Posterior wall breakage occurred in 7 cases (33.3%) with the TP technique and 1 case (3.3%) with the OI technique (P = .02). CONCLUSIONS: The mean femoral tunnel position was significantly shallower (arthroscopic position) with the OI technique than with the TP technique. The OI technique resulted in a more acute femoral graft bending angle, longer femoral tunnel length, and lower incidence of posterior wall breakage than did the TP technique. These results might be helpful for anatomic SB ACL reconstruction using TP and OI techniques. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

An in Vivo 3D Computed Tomographic Analysis of Femoral Tunnel Geometry and Aperture Morphology Between Rigid and Flexible Systems in Double-Bundle Anterior Cruciate Ligament Reconstruction Using the Transportal Technique.

PURPOSE: The aim of this study was to compare femoral tunnel length, femoral graft-bending angle, posterior wall breakage, and femoral aperture morphologic characteristics between rigid and flexible systems after double-bundle (DB) anterior cruciate ligament (ACL) reconstruction using the transportal (TP) technique. METHODS: We evaluated 3-dimensional computed tomography (3D-CT) results for 54 patients who underwent DB ACL reconstruction using the TP technique with either a flexible system (n = 27) or a rigid system (n = 27). The femoral tunnel length, femoral graft-bending angle, posterior wall breakage, femoral tunnel aperture height to width (H:W) ratio, aperture axis angle, and femoral tunnel position were assessed using OsiriX Imaging Software and Geomagic Qualify 2012 (Geomagic, Cary, NC). RESULTS: The mean anteromedial (AM) femoral tunnel length of the flexible group was significantly longer than that of the rigid group (P = .009). The mean femoral graft-bending angles in the flexible group were significantly less acute than those in the rigid group (AM, P < .001; posterolateral [PL], P = .003]. Posterior wall breakage was observed in both groups (P = 1.00). The mean H:W ratios in the rigid group were significantly larger (more elliptical) than those of the flexible group (AM, P < .001; PL, P = .006). The mean aperture axis angle of the PL femoral tunnel in the rigid group was more parallel to the femoral shaft axis than that in the flexible group (P < .001). There were no significant differences in femoral tunnel position between the 2 groups. CONCLUSIONS: The AM femoral tunnel length and the AM/PL femoral graft-bending angle of the flexible system were significantly longer and less acute than those of the rigid system. However, the aperture morphologic characteristics of the AM/PL femoral tunnel and the aperture axis angle of the PL femoral tunnel in the rigid system were significantly more elliptical and closer to parallel to the femoral shaft axis than those of the flexible system. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

High Axial Loads While Walking Increase Anterior Tibial Translation in Intact and Anterior Cruciate Ligament-Deficient Knees.

PURPOSE: To evaluate the effect of high axial loading (AL) on anterior tibial translation (ATT) according to the increase in knee flexion and the effect of valgus stress (VS) and internal rotation (IR) combined with high AL in intact and anterior cruciate ligament (ACL)-deficient knees according to the increase in knee flexion. METHODS: We used 10 fresh-frozen, human cadaveric knees. Different loading conditions (134-N anterior drawer, 1,000-N AL, 10-Nm VS, and 5-Nm IR) were sequentially combined, and ATT was measured at 0°, 15°, 30°, 45°, and 60° of flexion in the intact and ACL-deficient knees. RESULTS: ATT increased significantly by adding high AL in intact knees (P = .001) and ACL-deficient knees (P < .0001) according to the change in flexion angle (P < .0001). Under high AL, ATT in the ACL-deficient knees was significantly larger than that in the intact knees for all loading conditions, and it also increased gradually according to the increase in knee flexion (P = .0001). ATT increased significantly after adding IR or VS with high AL in intact knees (VS, P = .002; VS/IR, P = .03) and ACL-deficient knees (VS, P = .0004) at some of the flexion angles. CONCLUSIONS: The added high AL increased ATT in intact and ACL-deficient knees from 0° to 60° of flexion. The effect of high AL on ATT became greater in ACL-deficient knees than in intact knees, and ATT also gradually increased according to the increase in knee flexion from 0° to 60°. In both the intact and ACL-deficient knees, ATT increased significantly after valgus stress or IR from 0° to 60°. CLINICAL RELEVANCE: ATT during weight bearing increases stress to the ACL, which worsens with valgus stress and/or IR forces. This finding should be considered when one is studying ACL injury mechanisms, as well as prescribing rehabilitation after ACL surgery.

Effect of axial loading during knee flexion on ACL end-to-end distance in healthy and ACL-deficient knees.

PURPOSE: The purpose of this study was to determine the effect of physiological axial loading during knee flexion on changes in anterior cruciate ligament (ACL) end-to-end distance for normal and ACL-deficient knees. METHODS: Biomechanical tests were conducted on ten cadaveric knees using an Instron machine. We gathered positional data of the tibia and femur at low to middle flexion angles (0°, 15°, 30°, 45° and 60°) with/without axial loading. First, no external load was applied to the specimens at each angle, and then, a 1000-N axial load was applied to the knees. The same test protocols were repeated after transection of the ACL. Using computer software (Geomagic Studio 10), we regenerated positional data and calculated the end-to-end distances of the anteromedial, posterolateral and the entire ACL bundle at each angle. RESULTS: Compared with ACL-intact knees without axial loading, knees under axial loading did not show significant increases in end-to-end distance. Under axial loading, we found no significant differences in end-to-end distances between bundles in ACL-intact knees according to the increase in knee flexion angle. After ACL transection, axial loading significantly increased end-to-end distances of all three bundles (P < 0.001), and the distances increased significantly with flexion angle (P < 0.05 at all angles in all bundles). CONCLUSION: The changing patterns of the ACL end-to-end distance in ACL-deficient knees were different from those in healthy knees after applying physiological axial loading, and the ACL end-to-end distances in ACL-deficient knees increased remarkably as knee flexion angles increased.

Enhancement of tendon-bone healing with the use of bone morphogenetic protein-2 inserted into the suture anchor hole in a rabbit patellar tendon model.

BACKGROUND AIMS: Suture anchor fixation failure has been reported as a result of anchor loosening and migration during the tendon-bone repair. The aim of this study was to evaluate the effects of bone morphogenetic protein-2 (BMP-2) inserted into the suture anchor hole on bone formation and the tendon-bone healing. METHODS: Both back legs of 24 New Zealand White rabbits (n = 48) were used in this study. A metal suture anchor was then placed 5 mm below the cortex. In the control group, the space over the eyelet of the anchor (suture anchor hole) was not filled. In the experimental group, the suture anchor hole was filled with 0.1 mL of fibrin glue (group 2) or collagen gel (group 3) with 1 µg BMP-2. Histologic analysis, real-time-polymerase chain reaction, bone density and failure load measurement were performed, and differences were analyzed at 4 and 8 weeks. RESULTS: Histologic analysis revealed more abundant new bone, mature bone and organized fibrocartilage at the tendon-bone interface at 4 and 8 weeks in groups in which BMP-2 was applied. At 8 weeks, the failure load of groups 1, 2 and 3 was significantly different among the three groups (P = 0.01). After post hoc Tukey test, the failure load of group 2 was significantly higher than that of group 1 (P = 0.01). CONCLUSIONS: BMP-2, administrated as described in this study, improved tendon-bone healing and bone formation, resulting in improved biomechanical strength of the tendon-bone junction.

Comparison of femoral tunnel length between transportal and retrograde reaming outside-in techniques in anterior cruciate ligament reconstruction.

PURPOSE: To evaluate the accuracy of intraoperative femoral tunnel length measurement and to compare this between the transportal (TP) and outside-in (OI) techniques for double-bundle (DB) anterior cruciate ligament (ACL) reconstruction. METHODS: Eighty patients underwent a DB ACL reconstruction using either the TP or the OI technique. The participants were randomized to either a TP group (I, 40 cases) or a OI group (II, 40 cases). The intraoperatively measured femoral tunnel length was recorded, and the postoperative femoral tunnel length was measured using computed tomography with OsiriX(®) imaging software. RESULTS: The mean femoral tunnel lengths measured intraoperatively in Group II (38.9 ± 3.0 mm for anteromedial [AM], 39.3 ± 3.4 mm for posterolateral [PL]) were significantly longer than those of Group I (34.8 ± 2.7 mm for AM, 36.0 ± 3.2 mm for PL) (P < 0.001). The mean AM femoral tunnel length measured postoperatively in Group II (33.3 ± 3.8 mm) was significantly longer than that in Group I (31.1 ± 2.9 mm) (P = 0.006). The mean intraoperatively measured femoral tunnel length was significantly longer than that measured postoperatively in Groups I and II (P < 0.001). CONCLUSION: After anatomic DB ACL reconstruction, the femoral tunnel length of the OI technique measured intraoperatively (AM/PL) and postoperatively (AM) was longer than those of the TP technique. The femoral tunnel length measured intraoperatively was longer than that measured postoperatively in both TP and OI technique. This study may help surgeons to measure femoral tunnel length accurately in anatomic DB ACL reconstruction with suspensory fixation device.

Analysis of radiographic factors affecting the significant differences in knee alignment between hip-to-talus and hip-to-calcaneus radiographs after opening-wedge high tibial osteotomy.

BACKGROUND: Optimal alignment after opening-wedge high tibial osteotomy (OWHTO) is crucial for obtaining good clinical results. A hip-to-calcaneus radiograph (HCR) appears to reflect the true mechanical axis. However, no study has been reported using the HCR in patients who underwent OWHTO. We aimed to analyze the radiographic factors affecting the significant difference in the weight-bearing line (WBL) ratio between two radiographs after opening-wedge high tibial osteotomy (OWHTO). METHODS: This retrospective study included 51 patients who underwent both hip-to-talus radiographs (HTR) and HCR after OWHTO. The patients were divided into two groups; a consistent group (WBL ratio difference between postoperative HTR and HCR < 5%; N = 35) and an inconsistent group (> 5%; N = 16). Radiographic variables for lower extremity alignment, knee and ankle joints, and clinical scores were evaluated. The receiver operating characteristic curve was used to determine the threshold of radiographic variables that induced inconsistencies between the two radiographs. RESULTS: The mean postoperative WBL ratio in the HCR of the inconsistent group was significantly higher than that of the consistent group (57.7 ± 13.2% and 49.1 ± 11.6%, respectively) (P = 0.02). The preoperative and postoperative ankle joint line obliquity (AJLO) and preoperative lateral distal tibia ground surface angle (LDTGA) were significantly different between the two groups (P < 0.05). The preoperative AJLO (odds ratio 0.784, confidence interval 0.655-0.939, P = 0.008) significantly affected WBL ratio inconsistency. The cutoff value of the preoperative AJLO was 3.16°. However, clinical scores did not differ significantly between the two groups. CONCLUSION: The pre-and postoperative AJLO and the preoperative LDTGA were significantly different between the two groups. Among these variables, only preoperative AJLO negatively affected the inconsistency in WBL ratios between the two radiographs (HTT and HTC). Therefore, it should be considered to prevent postoperative overcorrection of the true mechanical axis after OWHTO, even though we corrected it properly. Level of evidence Level IV.

Safety and effectiveness of intra-articular injection of a highly cross-linked hyaluronic acid, LBSA0103 (Synovian): Results from a post-marketing surveillance study in South Korea.

This study aimed to assess the safety and effectiveness of the highly cross-linked hyaluronic acid-LBSA0103-in patients with knee osteoarthritis (OA) as per the prescribing information (PI) in South Korea. A total of 3,140 subjects aged ≥19 years were enrolled in this post-marketing surveillance (PMS) study from 2013 to 2019. The subjects received one or two injections of LBSA0103. The median duration of follow-up was 308 days. Adverse events (AEs), adverse drug reactions (ADRs), and serious AEs (SAEs) were monitored. Effectiveness was evaluated based on an index of effectiveness in accordance with the guidelines established by the Ministry of Food and Drug Safety and using a 100-mm visual analog scale (VAS) for weight-bearing pain. Overall, 250 subjects (7.96%) experienced 292 AEs and of these, unexpected AEs occurred in 114 subjects (3.63% [95% CI: 3.00-4.35]). Injection site pain was the most frequent AE reported by 81 subjects (2.58% [95% confidence intervals (CI): 2.05-3.20]). One hundred subjects experienced 108 ADRs (3.18% [95% CI: 2.60, 3.86]) and 15 unexpected ADRs were experienced by 13 subjects (0.41% [95% CI: 0.22-0.71]). Seventeen subjects experienced 22 SAEs (0.54% [95% CI: 0.32-0.87]) during the entire PMS period, and all were considered "unlikely" related to the study drug. Most AEs were mild in terms of severity and resolved during the study period. LBSA0103 was also effective in relieving symptomatic pain in knee OA patients. The condition in more than 80% of the subjects was considered to be improved when assessed by the investigators. LBSA0103 resulted in a significant reduction in the mean VAS score at 12 weeks after the first and second injections (24.79 (± 20.55) mm and 17.63 (±12.31) mm, respectively; p<0.0001). In conclusion, LBSA0103, used for the treatment of knee OA in a real-world setting, was well tolerated, with an acceptable safety profile and consistent therapeutic effect.

Long-term results of anterior cruciate ligament reconstruction using bone-patellar tendon-bone: an analysis of the factors affecting the development of osteoarthritis.

PURPOSE: To evaluate the clinical outcomes and incidence of knee osteoarthritis (OA) and the factors associated with the onset of OA in the 3 compartments of the knee joint separately after anterior cruciate ligament (ACL) reconstruction with bone-patellar tendon-bone autograft. METHODS: Clinical and radiologic assessments were obtained from 117 patients (80.1%). At follow-up, knee function was evaluated with the Lysholm score, Hospital for Special Surgery (HSS) score, Tegner score, and International Knee Documentation Committee (IKDC) 2000 forms. We also evaluated stability and donor-site morbidity. On the follow-up radiographs, OA was assessed by IKDC grading. The factors affecting the onset of OA in the 3 compartments of the knee joint were evaluated. RESULTS: The mean follow-up period was 10.3 ± 1.0 years. The mean Lysholm and HSS scores significantly increased at final follow-up (P < .001). The mean IKDC subjective score was 90.6, and 93.9% of patients had grade A or grade B knees on the objective evaluation. The mean side-to-side difference measured by KT-2000 arthrometer (MEDmetric, San Diego, CA) was 1.6 ± 1.7 mm, with 82.0% of patients showing a difference of less than 3 mm. Discomfort from knee walking on hard ground and skin numbness were reported by 38.4% and 37.6% of patients, respectively. OA developed in the medial, lateral, and patellofemoral compartments in 30.7%, 9.3%, and 7.6% of patients, respectively. The onset of OA was associated with partial meniscectomy (odds ratio [OR], 20.73; P = .005) or sagittal tibial tunnel position (OR, 1.18; P = .02) in the medial compartment and body mass index (BMI) (OR, 1.56; P = .02) in the lateral compartment. CONCLUSIONS: ACL reconstruction with bone-patellar tendon-bone autograft showed satisfactory clinical results after a mean of 10.3 years. However, pain when walking on hard ground (38.4%) and numbness of the skin (37.6%) were reported. Moreover, the onset of OA appeared in over 40% of the patients. The onset of OA in the medial compartment was correlated with partial meniscectomy and sagittal tibial tunnel position, and the onset of OA in the lateral compartment was correlated with higher BMI. LEVEL OF EVIDENCE: Level IV, therapeutic case series.