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Introduction The role of open cerclage wiring in comminuted femoral shaft fracture treatment with intramedullary nails remains unclear. Here, we analyzed the effect of open cerclage wiring and the risk factors for nonunion after interlocking nailing in comminuted femoral shaft fracture treatment. We hypothesized that open cerclage wiring can be applied in patients with severe comminuted femoral shaft fractures without affecting bone healing. Patients and methods This retrospective cohort study used data from consecutive patients who underwent interlocking nail fixation of a comminuted femoral shaft fracture between January 1, 2009, and December 31, 2016. First, eligible patients were divided into the wire and no wire groups according to the surgical technique used, and their union rate was recorded. The patients were then divided into the union and nonunion groups, and their perioperative data were analyzed. Results In total, 71 comminuted femoral shaft fractures treated with interlocking nail fixation were included: 38 fractures (53.5%) augmented with the open wiring technique and 33 reduced with closed or mini-open techniques without wiring. The wire group demonstrated significant improvements in fracture reduction compared with the no wire group, whereas no significant difference was observed in the union rate between the wire and no wire groups (p = 0.180). Moreover, 46 (65%) of 71 fractures achieved union smoothly, and no significant difference was observed in any perioperative data between the union and nonunion groups. Discussion Augmentation with open cerclage wiring is indicated for comminuted femoral shaft fractures treated with intramedullary nails, even when the fragments are large or greatly displaced. Thus, open cerclage wiring can be used for fracture treatment without decreasing the union rate.

BACKGROUND The brisement manipulation is an effective treatment for refractory shoulder stiffness. Rotator cuff tears can sometimes exist in combination with adhesive capsulitis. Arthroscopic capsular release combined with rotator cuff repair has achieved good outcomes in published reports. CASE SUMMARY We report the case of a patient with right shoulder pain for more than 1 year that was suspected to have adhesive capsulitis and a rotator cuff tear that was treated with brisement manipulation and arthroscopic management. An iatrogenic glenoid fracture with shoulder instability occurred during the manipulation. Arthroscopic treatment for fracture fixation, capsular release, and rotator cuff repair was performed, and the functional results are reported. CONCLUSION Arthroscopic fixation for iatrogenic glenoid fracture and repairing coexisting rotator cuff tear can provide the stability needed for early rehabilitation.

Purpose To compare the biomechanical properties of a high-tensile strength suture with the high-tensile strength tape for tendon graft fixation. Methods A total of 24 porcine tendons were used and were randomly divided into 2 groups. Two kinds of suture materials, a braided nonabsorbable high-strength suture (group S) and a high-tensile strength tape (group T), were used to complete 3 pairs of Krackow stitches on the tendons. Each specimen was pretensioned to 100 N for 3 cycles, cyclically loaded from 50 to 200 N for 200 cycles, and finally loaded to failure. Elongation after cyclic loading, ultimate failure load, and the mode of failure were recorded. Results The elongation after cyclic loading between group S (26% ± 5%) and group T (24% ± 5%) were not significantly different (P = .378). The ultimate failure loads in group T (400 ± 38 N) were significantly greater than those in group S (358 ± 21 N) (P = .010). All specimens failed because of suture material breakage. Conclusions Compared with the braided nonabsorbable high-strength suture, the high-tensile strength tape had similar elongation values after cyclic loading, but significantly greater ultimate failure load in this porcine in vitro biomechanical model. Clinical Relevance A secure suture-tendon construct is especially important when a post-tie fixation technique is used because the mitigating construct may potentially lead to graft loosening and affect graft healing.

To compare the biomechanical properties of the double simple suture (DSS) technique, Krackow suture (KS) technique, and double Krackow suture (DKS) technique in subpectoral biceps tenodesis using a double-loaded suture anchor in a porcine tendon model.A total of 30 artificial composite (polymer and glass fiber) humeri and porcine flexor profundus tendons with diameter of 4.5 mm were used. The sample size was determined based on the results of the pilot study. Metallic suture anchors with double-loaded No. 2 braided sutures were inserted at the subpectoral tenodesis site, 5 cm from the superomedial corner of the greater tuberosity. Three suture techniques were used to fix the tendons: a DSS used as the control, a KS, and a DKS, which is an alternative tendon graft fixation technique. A preload of 5 N was applied for 2 minutes, followed by cyclic loading for 500 cycles ranging from 5 to 70 N; next, a load-to-failure test at 1 mm/s was performed.The KS (283.5 ± 57 N) and DKS (270.4 ± 50 N) groups had significantly greater ultimate failure loads as compared with the DSS group (84.1 ± 6.4 N) (P.001). Meanwhile, the peak displacement at failure loads in the KS group (9.3 ± 2.2 mm) and DKS group (7.8 ± 1.7 mm) were significantly smaller than that of the DSS group (11.3 ± 2.9 mm) (P = .015). Stiffness in the DSS group (36.4 ± 3.0 N/mm), KS group (39.6 ± 2.5 N/mm), and DKS group (36.9 ± 4.6 N/mm) was not significantly different (P = .125). All DSS constructs and 6 KS constructs failed with tendons being cut through by the sutures, whereas the other 4 KS constructs and all DKS constructs failed resulting from suture breakage.In this subpectoral biceps tenodesis model, both the KS technique and the DKS technique had similar time 0 biomechanical properties that were better than those of the double simple suture technique.A sturdy suture-tendon structure could prevent clinical failure of a subpectoral biceps tenodesis using a suture anchor.

The Latarjet procedure is a reliable treatment for the management of anterior glenohumeral instability with glenoid bone loss. However, the biomechanical properties of different fixation angles between screw and glenoid surface (α angle) have rarely been studied. The aim of the study was to investigate and compare the fixation stability, failure load, and failure mechanism between different α angles for Latarjet procedures, which were performed on cadaver specimens.Twenty-four shoulder specimens (8 in each of 3 groups) were dissected free of all soft tissue, and a 25% glenoid defect was created. The coracoid process was osteomized and fixed with 2 screws at 3 different α angles: 0° (group A), 15° (group B), and 30° (group C). Specimens were mounted to a testing apparatus, and cyclic loading (100 cycles at 1 Hz) was applied with a staircase protocol (50, 100, 150, and 200 N). Gross graft displacement and interface displacement were measured. The ultimate failure loads and failure mechanisms were recorded.There was no significant difference in gross displacement under any cyclic load between 3 groups. However, a significant larger interface displacement was noted in group C than in group A in 150-N cyclic loading (P = .017). Under failure strength testing, all 24 specimens failed because of screw cutout from the glenoid, and the ultimate failure load was similar among the three groups.Compared with the 0° α angle, the displacement after cyclic loading did not significantly increase when the α angle was increased to 15° but significantly increased at 30° for Latarjet procedures, which were performed on cadaver specimens. The results suggest that surgeons should apply the screws as parallel as possible to the glenoid surface when performing the Latarjet procedure. Although mild deviation may not reduce fixation stability, α angles greater than 30° should be avoided.

Introduction Controversy exists regarding the use of reamed interlocking nailing in femoral shafts with extremely narrow medullary canals (diameter ≤ 9 mm). The aims of this study were to (1) investigate the association of age and sex on femoral canal diameter in patients with a simple femoral shaft fracture and (2) compare the outcomes and complications of interlocking nailing between wide and extremely narrow intramedullary canals. Patients and methods For the purposes of this retrospective cohort study, consecutive patients with simple femoral shaft fractures were recruited between January 2009 and December 2016. The patient demographic data were analyzed. Then, fractures treated with interlocking nailing were divided into the wide group (canal diameter > 9 mm) and narrow group. The primary outcome was union rate, and the secondary outcomes were complications such as thermal necrosis, fat embolism syndrome, iatrogenic fracture, and implant failure. Results This study included 340 femoral shaft fractures. The average canal diameter was 9.97 ± 1.79 mm, with significantly wider canals in men than in women. Overall, 289 of the patients had undergone interlocking nail fixation, and a similar union rate and complications were noted between the wide canal and narrow canal groups, with the exception of the incidence of iatrogenic fracture. Conclusions Femoral shaft fractures associated with extremely narrow medullary canals are more common in women than in men. There was a similar union rate found when using interlocking nailing in a femoral shaft fracture in cases with extremely narrow and wider canals. Iatrogenic fracture is the only significant risk when using interlocking nailing in femoral shafts with extremely narrow canals.

The purpose of this study is to determine the biomechanical properties of the bicortical off-axis screw fixation for stabilizing of Pauwels III femoral neck fractures compared with other fixation methods.Eighteen synthetic femurs (Sawbones Pacific Research Laboratories, Vashon, WA) were divided into three groups. The osteotomy was made vertically to mimic the Pauwels type III femoral neck fracture. Group A (n = 6) was fixed with traditional inverted triangle cannulated screws. Group B (n = 6) was fixed with a unicortical off-axis screw and two parallel cannulated screws. Group C (n = 6) was fixed with a bicortical off-axis screw and two parallel cannulated screws. Each group was tested with a nondestructive axial compression test at a 7° of valgus followed with 1000 cycles of cyclic loading test from 100 N to 1000 N. Finally, a destructive axial compression test was applied until catastrophic failure.The average axial stiffness from group A to group C was 856.5, 934, and 1340 N/mm, respectively. The average ultimate failure load from group A to group C was 2612.7, 2508.8, and 3706 N, respectively. Group C exhibited significantly greater axial stiffness and a higher ultimate failure load than the other two groups (P 0.05). Regarding the interfragmental displacement, the values from group A to group C were 0.41, 0.83, 0.36, respectively, and group B exhibited significantly larger fracture gap formation after the cyclic loading test.The results of this biomechanical study show statistically significant increases in axial stiffness and ultimate failure load for the off-axis screw placed in bicortical fashion. Once the off-axis screw was positioned unicortically, the largest fracture diastasis was observed as compared to the other two methods.

In large or massive rotator cuff tears, successful repairs are difficult and complication rates are high, because the torn tendon is contracted and the superior capsule is disrupted. Recent studies have shown that superior capsule reconstruction (SCR) in massive irreparable rotator cuff tears results in better clinical scores and preserves stable glenohumeral stability without significant complications. In this article, we propose a simple, efficient SCR technique to reinforce the repair of large or massive rotator cuff tears. For this technique, the long head of the biceps tendon is used as a local autograft for the SCR, therefore eliminating comorbidities related to graft harvesting. The proximal part of the long head of the biceps tendon is transposed posteriorly and fixed onto the footprint as the SCR, which not only can maintain the stability of the glenohumeral joint, but also can preserve the vascular supply to help healing.

Case A 45-year-old woman sustained a unique lateral tibia plateau fracture pattern with a vertically rotated fragment composed of an intact articular surface and subchondral bone. During open reduction and internal fixation (ORIF), a full thickness radial tear of the lateral meniscus was found, which was repaired under direct visualization through arthrotomy. At final follow-up, the patient regained pain-free activity with good meniscus healing, as confirmed with a second-look arthroscopic examination. Conclusion This case represents an undescribed fracture pattern that indicates an associated meniscus injury. A thorough evaluation, including Magnetic Resonance Imaging should be considered. One-stage ORIF followed with meniscus repair represents a good treatment option.

Background The posterior plating technique could be used as a clinical alternative to parallel plating for treating comminuted distal humerus fractures (DHFs) successfully with good clinical results. However, the biomechanical characteristics for posterior fixation are still unclear. The purpose of this study is to evaluate the biomechanical properties of the posterior fixation and to make comparisons between the parallel and the posterior fixation systems. Materials and methods We performed a cadaveric biomechanical testing with two posterior plating systems (a posterior two plating and a single posterior pre-contoured Y plating system) and one parallel two plating system to treat AO/OTA type-C2.3 DHFs. Among three groups, we compared construct stiffness, failure strength, and intercondylar width changes after 5000-cycle fatigue loading and failure loads and failure modes after destructive tests in both the axial compression and (sagittal) posterior bending directions. The correlations between construct failure loads and bone marrow density (BMD) were also compared. Results In axial direction, there were no significant differences in the stiffness and failure load between the posterior and the parallel constructs. However, in sagittal direction, the two-plate groups (posterior two plating and parallel plating group) had significant higher stiffness and failure loads than the one-plate group (single posterior Y plating). There was no fixation failure after 5000-cyclic loading in both directions for all groups. Positive correlation was noted between BMD and failure loads on parallel fixation. Conclusions We found that when using two plates for treating comminuted DHFs, there were no significant differences in terms of most biomechanical measurements between posterior and parallel fixation. However, the single pre-contoured posterior Y plate construct was biomechanically weaker in the sagittal plane than the parallel and the posterior two-plate constructs, although there was no fixation failure after the fatigue test for all groups regardless of the fixation methods. Level of evidence Biomechanical study

IntroductionThe role of open cerclage wiring in comminuted femoral shaft fracture treatment with intramedullary nails remains unclear. Here, we analyzed the effect of open cerclage wiring and the risk factors for nonunion after interlocking nailing in comminuted femoral shaft fracture treatment. We hypothesize that open cerclage wiring is applicable to patients with severe comminuted femoral shaft fractures without affecting bone healing.Patients and MethodsThis retrospective cohort study used data of consecutive patients who underwent interlocking nail fixation of a comminuted femoral shaft fracture between January 1, 2009, and December 31, 2016. First, eligible patients were divided into wire and no wire groups according to the surgical technique used and their union rate was recorded. The patients were then divided into union and nonunion groups and their perioperative data were analyzed.ResultsIn total, 71 comminuted femoral shaft fractures treated with interlocking nail fixation were included: 38 fractures (53.5%) augmented with the open wiring technique and 33 reduced with closed or mini–open wound without wiring. The wire group demonstrated significant improvements in fracture reduction compared with the no wire group, whereas no significant difference was observed in the union rate between the wire and no wire groups (p = 0.180). Moreover, 46 (65%) of 71 fractures united smoothly, and no significant difference was observed in any perioperative data between union and nonunion groups.DiscussionAugmented open cerclage wiring is indicated for comminuted femoral shaft fractures treated with intramedullary nails, even when the fragments are large or far displaced. Thus, open cerclage wiring can be used for fracture treatment, without decreasing the union rate.

PURPOSE The aim of this study was to develop a non-cytotoxic, biocompatible innovative acellular porcine cornea (APC) for corneal wound healing and corneal blindness treatment. METHODS APC was produced by using supercritical carbon dioxide (SCCO2) to decellularize the porcine cornea. Decellularization of the porcine cornea was examined by hematoxylin and eosin staining and 4,6-diamidino-2-phenylindole, dihydrochloride staining. The residual DNA content of APC was analyzed in comparison with the native porcine cornea. Virus inactivation up to at least 6 log10 was confirmed for the stepwise process of APC for 4 different model viruses. In addition, a series of in vitro and in vivo tests in accordance with ISO-10993 biocompatibility assay and animal performance tests were performed. RESULTS APC produced by the SCCO2 process revealed complete decellularization, without any residual non-collagenous proteins. The scanning electron microscopy structural features of the decellularized cornea were similar to those of human. APC was found to be nontoxic and exhibited excellent biocompatibility in both in vitro and in vivo studies. The animal performance test proved that APC exerted excellent adaptability on the cornea and no sign of irritation and good compatibility in lamellar corneal transplantation. CONCLUSIONS APC manufactured by SCCO2 technology revealed complete cells and non-collagenous protein removal compared with the Triton-sodium dodecyl sulfate decellularization process. APC showed excellent biocompatibility in rabbit lamellar corneal transplantation with a follow-up to 1 year. APC can be a potential substitute for human-donated cornea for corneal transplantation in the near future.

To retrospectively assess the clinical outcomes of the patients with large to massive reparable RCTs treated by arthroscopic rotator cuff repair (ARCR) combined with modified superior capsule reconstruction (mSCR) using the long head of biceps tendon (LHBT) as reinforcement with a minimum of 2 years of follow-up.We retrospectively evaluated 40 patients with large to massive reparable RCTs who underwent ARCR and mSCR (group I) between February 2017 and June 2018 (18 patients) or underwent ARCR and tenotomy of LHBT performed at the insertion site (group II) between January 2015 and January 2017 (22 patients). The pain visual analog score (VAS) was assessed preoperatively and 1, 3, 6, 12, 24 months postoperatively. American Shoulder and Elbow Surgeons (ASES) scores, the University of California, Los Angeles (UCLA) shoulder rating scale, and active range of motion (AROM) were assessed before surgery and 6, 12, and 24 months after surgery. The integrity of the rotator cuff and mSCR was evaluated using magnetic resonance images at 12 months postoperatively.After surgery, both groups had significantly improved in VAS, ASES, UCLA and AROM scores in the final follow-up. There were no significant between-group differences in the characteristics of the patients before surgery. Group I had improved pain relief at 1 month (P.001) and at 3 months (P.01) after surgery. For the AROM, group I (flexion, external rotation, internal rotation) demonstrated better improvement than group II 6 months after surgery (all P.05) and better internal rotation 12 and 24 months after surgery (all P.05). The mSCR survival rate was 94.4% (17/18). The retear rate of repaired rotator cuffs for groups I and II was 16.7% (3/18) and 40.9% (9/22), respectively, and the differences were significant (P.046).ARCR combined with mSCR using LHBT as reinforcement may lead to a lower retear rate and earlier functional recovery than conventional ARCR with tenotomy of LHBT for large to massive reparable RCTs.Level III, retrospective therapeutic comparative trial.

Objectives: Tenotomy and tenodesis of the long head of biceps tendon are effective pain-relieving treatments. However, there is no consensus on the functional outcome after these surgical procedures. We hypothesized that there would be no difference in ambulation parameters after recovery from the surgery between rats that underwent tenotomy versus tenodesis procedures. Methods: Twenty-four New Zealand rats were used and randomly divided into three groups. Each group received one of the following surgeries: tenotomy, tenodesis, and sham operation. A video-based walking track system was applied for gait analysis at day −1, 1, 3, 5, 7, 14 and 21 for each rat. Temporal and spatial parameters were obtained, and asymmetric index was calculated for each parameter. Results: Compared to the tenotomy and sham-operated groups, the rats in the tenodesis group had shorter stance phase, longer swing time, longer step length, smaller paw length, smaller intermediary toe-spread length, smaller toe-spread length, and larger foot angle right after the tenodesis procedure. After day 14, all parameters were equivalent to those of the sham-operated group. At the end of the study, there were no functional changes found in tenotomy and tenodesis groups compared with the sham-operated group and preoperative status. Conclusion: Transient functional alterations in temporal and spatial parameters are found after tenotomy and tenodesis in a rat model. The functional changes in the tenodesis group existed for a longer period than in tenotomy group; however, and all parameters showed no significant differences when compared with the sham group at the conclusion of the study. Keywords: Long head of biceps tendon, Tenotomy, Tenodesis, Gait analysis, Functional outcome, Asymmetric index

To prospectively compare the efficacy of intra-articular injections of platelet-rich plasma (PRP) and hyaluronic acid (HA) with a sham control group (normal saline solution [NS]) for knee osteoarthritis in a randomized, dose-controlled, placebo-controlled, double-blind, triple-parallel clinical trial.A total of 87 osteoarthritic knees (53 patients) were randomly assigned to 1 of 3 groups receiving 3 weekly injections of either leukocyte-poor PRP (31 knees), HA (29 knees), or NS (27 knees). The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score and International Knee Documentation Committee (IKDC) subjective score were collected at baseline and at 1, 2, 6, and 12 months after treatment. Data were analyzed using generalized estimating equations.All 3 groups showed statistically significant improvements in both outcome measures at 1 month; however, only the PRP group sustained the significant improvement in both the WOMAC score (63.71 ± 20.67, increased by 21%) and IKDC score (49.93 ± 17.74, increased by 40%) at 12 months. For the intergroup comparison, except for the first month, there was a statistically significant difference between the PRP and NS groups in both scores throughout the study duration (regression coefficients of 8.72 [P = .0015], 7.94 [P = .0155], and 11.92 [P = .0014] at 2, 6, and 12 months, respectively, for WOMAC score, and 9.1 [P = .0001], 10.28 [P = .0002], and 13.97 [P.0001], respectively, for IKDC score). There was no significant difference in both functional outcomes between the HA and NS groups at any time point. Only the PRP group reached the minimal clinically important difference in the WOMAC score at every evaluation (15%, 21%, 18%, and 21% at 1, 2, 6, and 12 months, respectively) and the minimal clinically important difference in the IKDC score at 6 months (improvement of 11.6).Intra-articular injections of leukocyte-poor PRP can provide clinically significant functional improvement for at least 1 year in patients with mild to moderate osteoarthritis of the knee.Level I, randomized controlled single-center trial.

Background The role of locking plate in lateral malleolar fracture fixation for the elderly remains unclear. The aim of our study is to compare radiological and functional outcomes in older patients (> 50 years) with AO/OTA 44B lateral malleolar fractures after locking plate (PLP) or one-third non-locking tubular plate (TP) lateral fixation. Methods We retrospectively reviewed the medical records of 72 patients (PLP group, 34 patients; TP group, 38 patients; mean age, 61.9 ± 7.6 years; range, 51–80 years; follow-up, 1 year). Patients with open fractures, syndesmosis injuries, and a previous ankle trauma or surgery were excluded. Demographic data, union rate, complications, radiographic outcomes, visual analog scale (VAS) scores, and foot and ankle outcome scores (FAOSs) between the groups were recorded and compared. We also investigated the association of clinical features with pain and function. Statistically, the Fisher’s exact test was used for categorical variables and the Mann-Whitney U test for the continuous variables. The final model for the multiple regression analysis was used to predict factors related to functional outcomes. Results There were no significant between-group differences in demographic data, complication rates, immediately postoperative distal fibula lengths, ankle osteoarthritis (OA) grades, talar tilt angles (TTAs) ≥ 2°, or reduction accuracy. All fractures achieved union. The PLP group had significantly lower rates of distal screw loosening, fibula shortening > 2 mm, OA grade progression, and TTAs ≥ 2°, and better FAOSs and VAS scores than was the case for the TP group after 1 year of follow-up (all p < 0.05). The severity of OA, TTA ≥ 2°, and distal screw loosening were positively associated with VAS scores, and negatively associated with FAOSs. Conclusions When treating AO/OTA 44B fractures in patients over 50 years of age, PLPs provided better VAS scores, FAOSs, and radiological outcomes, including less fibula shortening > 2 mm, less osteoarthritic (OA) ankle progression, less implant removal rate, and fewer TTAs ≥ 2° than was the case for TPs after a 1-year follow-up. Level of evidence Therapeutic level III

Background: The intraoperative invisible middle glenohumeral ligament (MGHL) test has been shown to be associated with a subscapularis tendon retraction. However, the preoperative location of the MGHL and its association with subscapularis tear severity has not been evaluated. Purpose: To determine (1) the interrater reliability for identification and position of the MGHL, (2) any association between the MGHL position and subscapularis tears, and (3) the cutoff point at which MGHL position can predict subscapularis tear severity. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: The magnetic resonance imaging (MRI) scans and surgical records of 176 patients were retrospectively reviewed by 3 independent orthopaedists. MGHL's identification, level (its position on axial MRI), and medial retraction ratio (distance from the lesser tuberosity to the MGHL divided by the width of the glenoid) were documented, and the interobserver agreement of the 3 indices was assessed. We calculated the association between subscapularis tears and the MGHL level and medial retraction ratio. Receiver operating characteristic (ROC) curve analyses were conducted to establish the optimal threshold of the MGHL medial retraction ratio to predict subscapularis tear. Results: The MGHL was identified by at least 2 reviewers in 124 individuals (70.5%). The interobserver reliability was very good for MGHL identification (κ = 0.766), moderate for MGHL level (κ = 0.582), and excellent for MGHL medial retraction ratio (intraclass correlation coefficient = 0.848). A low, positive correlation between MGHL level and subscapularis tear severity was found (Somers d = 0.392, P < .001), as well as a significant association between the medial retraction ratio and Lafosse classification of subscapularis tear size ( P < .001). A medial retraction ratio of ≥1.25 had a sensitivity of 0.70, a specificity of 0.83, and a positive likelihood ratio of 4.20, with excellent accuracy (area under the ROC curve = 0.820) to predict severe subscapularis tear. Conclusion: The MGHL was identified in 70.5% of shoulder MRIs. The location of the MGHL on preoperative MRI, as described by its level and the medial retraction ratio, was significantly associated with subscapularis tear severity, and a medial retraction ratio of ≥1.25 was predictive of a severe subscapularis tear.

In the present study, we fabricated non-toxic, injectable, and thermo-sensitive NIPAAm-g-chitosan (NC) hydrogels with thiol modification for introduction of disulfide cross-linking strategy. Previously, NIPAAm and chitosan copolymer has been proven to have excellent biocompatibility, biodegradability and rapid phase transition after injection, suitable to serve as cell carriers or implanted scaffolds. However, weak mechanical properties significantly limit their potential for biomedical fields. In order to overcome this issue, we incorporated thiol side chains into chitosan by covalently conjugating N-acetyl-cysteine (NAC) with carbodiimide chemistry to strengthen mechanical properties. After oxidation of thiols into disulfide bonds, modified NC hydrogels did improve the compressive modulus over 9 folds (11.4 kPa). Oscillatory frequency sweep showed a positive correlation between storage modulus and cross-liking density as well. Additionally, there was no cytotoxicity observed to mesenchymal stem cells, fibroblasts and osteoblasts. We suggested that the thiol-modified thermo-sensitive polysaccharide hydrogels are promising to be a cell-laden biomaterial for tissue regeneration.

Purpose To compare the biomechanical properties of an transtendinous all-suture anchor technique with the commonly-accepted interference screw technique in a cadaveric model. Methods Sixteen fresh-frozen human cadaveric shoulders (mean age, 67.6 ± 5.8 years) were used and were randomly divided into 2 experimental long head of the biceps brachii (LHB) tenodesis groups (n = 8), namely transtendinous all-suture anchor technique and interference screw technique. The location of tenodesis was in the bicipital groove, 1 cm distal to the proximal border of the bicipital groove. Tensile force parallel to the longitudinal axis of the humerus was applied to each specimen. A preload of 5 N was applied for 2 minutes, followed by cyclic loading for 500 cycles from 5 to 70 N at 1 Hz; then, a load-to-failure test at 1 mm/s was performed. The ultimate failure load, stiffness, cyclic displacement, failure displacement, and failure modes were recorded. Results The transtendinous all-suture anchor technique provided similar ultimate failure load and stiffness as the interference screw technique. However, the cyclic and failure displacements of the transtendinous all-suture anchor technique were significantly greater than the interference screw technique ( P = .009 and .021, respectively). Six specimens in the transtendinous all-suture anchor group failed because of suture anchor pullout, while failure of the other 2 was caused by tendon tear; by contrast, all specimens in the interference screw group failed because of tendon tear. Conclusions The transtendinous all-suture anchor technique for LHB tenodesis offered equivalent ultimate failure load and stiffness but had significantly larger cyclic and failure displacement values when compared with the interference screw technique in this cadaveric biomechanical study. Clinical Relevance The transtendinous all-suture anchor technique is an alternative technique for suprapectoral LHB tenodesis; however, care should be taken because only time zero biomechanical data are available.

Purpose The purpose of this study was to compare the biomechanical properties among the different double Krackow suture techniques for tendon graft fixation. Methods Thirty porcine flexor profundus tendons were randomly divided into 3 groups of 10 specimens each. Three different double Krackow suture techniques were evaluated, namely, the McKeon's double Krackow (MDK) suture, Wilson's double Krackow (WDK) suture, and Ostrander's modified Krackow (OMK) suture. All suture configurations were completed with a braided nonabsorbable suture. Each suture-tendon construct was pretensioned to 100 N for 3 cycles, cyclically loaded from 50 to 200 N for 200 cycles, and then finally loaded to failure. Elongation after cyclic loading, ultimate load to failure, and the mode of failure were recorded for each specimen. Results There were significant differences in elongation after cyclic loading among the MDK suture (7.9 ± 3.6 mm, 14% ± 6%), WDK suture (11.6 ± 2.2 mm, 22% ± 3%), and OMK suture (9.6 ± 3.3 mm, 17% ± 6%; P = .018). In addition, although the post hoc analysis showed that elongation after cyclic loading in the MDK suture was significantly less than the WDK suture ( P = .004), ultimate failure load and cross-sectional area were not significantly different across the 3 groups. Conclusions In this porcine in vitro biomechanical study, the MDK suture had significantly smaller elongation after cyclic loading than the WDK suture; however, high elongation values may have a potential for risk of clinical laxity. The ultimate failure load was not different across the MDK, WDK, and OMK sutures. Clinical Relevance Smaller elongation during cyclic loading in a suture-tendon construct represents a lower possibility of tendon graft loosening after ligament reconstruction surgery. The double Krackow suture techniques are attractive options for tendon graft fixation in ligament reconstruction, and the MDK suture could possibly be the optimal choice among the double Krackow suture techniques.

Outerbridge–Kashiwagi ulnohumeral arthroplasty is an effective method in treating elbow osteoarthritis; however, distal humerus fracture after surgery can become a critical issue. A previous biomechanical study has shown that the failure load of the distal humerus decreases after a fenestration, but the size of the fenestration hole has not yet been discussed. 32 fresh-frozen cadaveric distal humeri were obtained. Two drill sizes were chosen for fenestration: 12 and 15 mm in diameter. Two directions of force were applied with a materials testing machine for biomechanical testing: 5° flexion for axial loading and 75° flexion for anterior–posterior (AP) loading. Each specimen randomly received one of the two fenestration sizes, and force directions. All specimens were loaded to failure at a rate of 2 mm/min. The failure loads of the 12 and 15 mm groups were not significantly different in either axial loading(3886 ± 1271 N vs 4286 ± 901 N) or AP loading(2303 ± 803 N vs 1897 ± 357 N). All specimens loaded with axial force failed via the fenestration holes; however, during AP loading, some specimens failed through the fenestration holes, while others at diaphysis (p = 0.28). The failure load of distal humeri did not differ significantly after fenestration of 12 or 15 mm. The clinical relevance is that as the risk of distal humerus fracture is not exacerbated, a larger-size fenestration hole could be of help to improve the effectiveness of this surgical procedure.

The hydrothermal treatment followed by a self-assembled monolayer (SAM) of 1-butylphosphonic acid through the tethering by aggregation and growth (T-BAG) method was employed to produce protective surface coatings on the Mg-6Al-1Zn alloy (AZ61) for reducing the degradation rate in physiological environments. Potentiodynamic polarization measurements revealed that the organic self-assembled monolayer and Mg(OH)2 coating can further enhance the surface chemical stability and corrosion resistance of Mg alloys. SAM-treated Mg(OH)2 coatings can be served as a more passive surface layer as a result of their much higher charge transfer resistance and the presence of Warburg impedance in electrochemical impedance spectroscopy measurement.

Introduction The purpose of this study was to delineate the anatomic relationship between the anterior articular capsule and the adjacent subscapularis by measuring the dimensions of the anterior articular capsule attachment and the subscapularis footprint on the humerus, as well as investigating the interface between the two structures. Materials and methods Three shoulder specimens underwent histological analysis; for histological analysis, cross-sections through the subscapularis-capsule complex were harvested at the tendinous and muscular insertion sites. The dimensions of the anterior articular capsule attachment and the subscapularis footprint (including the tendinous and muscular insertions) were measured in thirteen cadaveric shoulder specimens. Results Histologically, the articular capsule has thin and loosely arranged collagen fibers with many interspersing fibroblast nuclei, whereas the outer layer of the articular capsule blends into a layer of more loosely spaced and less organized collagen fibers. This interface between the subscapularis and the underlying articular capsule is filled with more loosely spaced and less organized collagen fibers. The macroscopic evaluation showed that the minimum articular capsule width (4.2 mm, SD 2.2 mm) was located at its initiation 4.9 mm (SD, 2.1 mm) inferior to the superior margin of the subscapularis; the corresponding subscapularis footprint width measured 10.1 mm (SD, 4.9 mm). The maximum articular capsule width was11.1 mm (SD, 3.7 mm) and was located 5 mm distal to the inferior margin of the tendinous footprint. The maximum subscapularis footprint width was 15.8 mm (SD, 2.9 mm); the corresponding articular capsule attachment measured 5.2 mm (SD, 1.8 mm). Conclusions Our results suggest that the anterior articular capsule attachment of the glenohumeral joint complements the footprint of the subscapularis and occupies a larger area of the lesser tubercle and metaphysis of the humerus than previously documented. The histological study confirms the presence of a demarcation between the subscapularis and articular capsule, specifically more significant at the region medial to the tendon insertion and at the muscular insertion of the subscapularis.

Introduction Modified tension band wiring has been widely used to treat transverse patellar fractures. However, few studies have evaluated the clinical outcomes using different methods of Kirschner wire bending, location of the tension band, and depths of Kirschner wires. Thus, we tried to clarify these factors according to our clinical outcomes. Patients and methods This retrospective cohort study recruited consecutive patients underwent surgical fixation for patellar fractures using modified tension band technique between January 2010 and December 2015. Different factors in this procedure, including the bending manner of the Kirschner wires, their depth, and location of the tension band with respect to the superior and inferior border of the patella were recorded and analysed. The primary outcome was early loss of fixation. The secondary outcomes were minor loss of reduction, implant breakage, deep infection, and the need for implant removal. Results This study included 170 patients with patellar fractures. Regarding the bending method, similar results were obtained with bilaterally or proximally bent Kirschner wires. Regarding length, the tension band was placed closely (within 25% of the patella length) in 124 patients and distantly in 46 patients. The rates of loss of reduction and implant breakage were significantly higher in the distantly placed tension bands. Regarding depth, 37 patellar fractures were fixed with the Kirschner wires at the superficial one third of the patellae while the K- wires at the middle layer of patella were used in the remaining 133 patellar fractures. A significantly higher rate of minor loss of reduction was obtained using the superficial Kirschner wires. Conclusion The modified tension band technique for transverse patella fractures provides favourable clinical outcomes, with low failure (5%) and infection (2%) rates. Implant irritation is the major complication, and almost half of cases require implant removal. The location of the tension band with respect to the superior and inferior border of the patella plays an important role in clinical outcomes. Placing the wire close to the patella may prevent major loss of reduction and implant breakage. Superficially placed Kirschner wires also affect clinical outcomes by increasing the rate of minor loss of reduction.

A duplex surface-modification technique that combines ultrasonic-assisted etching and the fluoride-conversion method was successively applied on the surface of a Mg alloy, and was called the MagNest surface. The results showed that the MagNest surface possessed bowl-like nest structures about 15–35 µm in diameter and 2–5 µm in depth. Electrochemical testing verified that the corrosion resistance was increased, indicating that corrosion was effectively inhibited by the surface modification. The MagNest surface also exhibited non-cytotoxicity for MG63 osteoblast-like cells, with most adhered MG63 cells rapidly extending their cell membrane and filopodia. This demonstrates the excellent cytocompatibility of this surface modification, and so constitutes a promising biodegradable material.