Fixation technique of biodegradable magnesium alloy suture anchor in the rotator cuff repair of the shoulder in a goat model: a technical note.

BACKGROUND: Shoulder disorders, particularly rotator cuff tears, are prevalent musculoskeletal conditions related to aging. Although the widely used suture anchor technique provides strong mechanical support to the tendon, it is associated with a risk of postoperative tendon retearing. The conventionally used titanium alloys can affect the interpretation of magnetic resonance imaging. Degradable magnesium alloys possess excellent biocompatibility, similar mechanical property to the bone, and stimulating bone formation ability from Mg2+. The purpose of this experiment was to develop innovative magnesium-based suture anchors to enhance rotator cuff repair by improving fixation materials, and to evaluate their feasibility in a goat model. METHODS: We developed fluoridized ZK60 suture anchors as the implantation material for two goats, who underwent rotator cuff repair surgery on both shoulders. Computed tomography (CT) and histological analysis were performed at 12 weeks postoperatively, and the results were compared between the magnesium and titanium alloy groups. Additionally, a hematological examination was conducted, which included assessments of red blood cells, white blood cells, platelets, coagulation function, liver function, kidney function, and magnesium ion concentration. RESULTS: The 12-week postoperative CT images showed intact MgF2 ZK60 suture anchors, effectively reconnecting the infraspinatus tendon to the humeral head. The anchors became less visible on CT scans, indicating absorption by surrounding tissues. New bone formation in the MgF2 group surpassed that in the Ti group, demonstrating superior osseointegration. The similarity between cortical bone and magnesium reduced stress-shielding and promoted bone regeneration. Histological analysis revealed successful tendon healing with MgF2 anchors, while the Ti group showed discontinuous interfaces and reduced collagen secretion. Hematological examination showed stable liver, renal function, and magnesium ion levels. CONCLUSIONS: The findings indicate that MgF2-coated suture anchors are feasible for rotator cuff repair and potentially other orthopedic applications. We hope that magnesium alloy anchors can become the solution for rotator cuff tendon repair surgery.

Characterizing the Impact of Compression Duration and Deformation-Related Loss of Closure Force on Clip-Induced Spinal Cord Injury in Rats.

The clip-induced spinal cord injury (SCI) rat model is pivotal in preclinical SCI research. However, the literature exhibits variability in compression duration and limited attention to clip deformation-related loss of closure force. We aimed to investigate the impact of compression duration on SCI severity and the influence of clip deformation on closure force. Rats received T10-level clip-induced SCI with durations of 1, 5, 10, 20, and 30 s, and a separate group underwent T10 transection. Outcomes included functional, histological, electrophysiological assessments, and inflammatory cytokine analysis. A tactile pressure mapping system quantified clip closure force after open-close cycles. Our results showed a positive correlation between compression duration and the severity of functional, histological, and electrophysiological deficits. Remarkably, even a brief 1-s compression caused significant deficits comparable to moderate-to-severe SCI. SSEP waveforms were abolished with durations over 20 s. Decreased clip closure force appeared after five open-close cycles. This study offers critical insights into regulating SCI severity in rat models, aiding researchers. Understanding compression duration and clip fatigue is essential for experiment design and interpretation using the clip-induced SCI model.

Full Endoscopic Spine Surgery for Cervical Spondylotic Myelopathy: A Systematic Review.

BACKGROUND: Cervical spondylotic myelopathy (CSM) may seriously affect quality of life. In the literature, there is scarce evidence of the pros and cons of full endoscopic spine surgery in the treatment of CSM. The main purpose of this study was to conduct a systematic review to elucidate the efficacy of full endoscopic spine surgery in the management of patients with CSM. METHODS: This systematic review was conducted in accordance with the PRISMA guidelines. A systematic search of Web of Science, PubMed MEDLINE, Embase, and Cochrane Library was conducted from the database inception to February 1, 2023. RESULTS: The study included 183 patients and their age was 56.78 ± 7.87 years. The average surgical time calculated was 96.34 ± 33.58 minutes. Intraoperative blood loss ranged from a minimal amount to 51 mL. The average duration of hospital stay was 3.56 ± 1.6 days. The average span for follow-up was on an interval of 18.7 ± 6.76 months. Significant improvements were noted in all aspects of functional outcomes and image results after full endoscopic cervical spine surgery, with no major complications. CONCLUSIONS: The current study found that both anterior transcorporeal and posterior surgical approaches could be used for the treatment of CSM with a full endoscopic technique. Indications of full endoscopic cervical spine surgery for CSM included cervical disc herniation, central canal stenosis, calcified ligamentum flavum, and ossification of the posterior longitudinal ligament. Improved postoperative outcomes with acceptable surgical complications were noted in this systematic review.

Influence of Spin Coating and Dip Coating with Gelatin/Hydroxyapatite for Bioresorbable Mg Alloy Orthopedic Implants: In Vitro and In Vivo Studies.

Suitable biomechanical properties, good biocompatibility, and osteoconductivity of a degradable magnesium (Mg) alloy make it a potential material for orthopedic implants. The main limitation of Mg is its high corrosion rate in the human body. Surface modification is necessary to improve the Mg corrosion resistance. In this work, a polymeric layer of gelatin/nanohydroxyapatite (Gel/nHA) was coated on a ZK60 Mg alloy by dip coating and spin coating to test the corrosion resistance and biocompatibility in vitro and in vivo. The results from the in vitro test revealed that the coated groups reduced the corrosion rate with the corrosion current density by 59 and 81%, from 31.22 to 12.83 µA/cm2 and 5.83 µA/cm2 in the spin coating and dip coating groups, respectively. The dip coating group showed better corrosion resistance than the spin coating group with the lowest released hydrogen content (17.5 mL) and lowest pH value (8.23) and reducing the current density by 45%. In vitro, the relative growth rate was over 75% in all groups tested with MG63, demonstrating that the Mg substrate and coating materials were within the safety range. The dip coating and spin coating groups enhanced the cell proliferation with significantly higher OD values (3.3, 3.0, and 2.5, respectively) and had better antihemolysis and antiplatelet adhesion abilities than the uncoated group. The two coating methods showed no difference in the cellular response, cell migration, hemolysis, and platelet adhesion test. In in vivo tests in rats, the dip coating group also showed a higher corrosion resistance with a lower corrosion rate and mass loss than the spin coating group. In addition, the blood biochemistry and histopathology results indicated that all materials used in this study were biocompatible with living subjects. The present research confirmed that the two methods have no noticeable difference in cell and organ response but the corrosion resistance of dip coating was higher than that of spin coating either in vitro or in vivo.

Association Between Medial Displacement of the Middle Glenohumeral Ligament and Subscapularis Tear Severity.

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.

Biomechanical comparison between various screw fixation angles for Latarjet procedure: a cadaveric biomechanical study.

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Acellular Porcine Cornea Produced by Supercritical Carbon Dioxide Extraction: A Potential Substitute for Human Corneal Regeneration.

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.

Restoring Osteochondral Defects through the Differentiation Potential of Cartilage Stem/Progenitor Cells Cultivated on Porous Scaffolds.

Cartilage stem/progenitor cells (CSPCs) are cartilage-specific, multipotent progenitor cells residing in articular cartilage. In this study, we investigated the characteristics and potential of human CSPCs combined with poly(lactic-co-glycolic acid) (PLGA) scaffolds to induce osteochondral regeneration in rabbit knees. We isolated CSPCs from human adult articular cartilage undergoing total knee replacement (TKR) surgery. We characterized CSPCs and compared them with infrapatellar fat pad-derived stem cells (IFPs) in a colony formation assay and by multilineage differentiation analysis in vitro. We further evaluated the osteochondral regeneration of the CSPC-loaded PLGA scaffold during osteochondral defect repair in rabbits. The characteristics of CSPCs were similar to those of mesenchymal stem cells (MSCs) and exhibited chondrogenic and osteogenic phenotypes without chemical induction. For in vivo analysis, CSPC-loaded PLGA scaffolds produced a hyaline-like cartilaginous tissue, which showed good integration with the host tissue and subchondral bone. Furthermore, CSPCs migrated in response to injury to promote subchondral bone regeneration. Overall, we demonstrated that CSPCs can promote osteochondral regeneration. A monophasic approach of using diseased CSPCs combined with a PLGA scaffold may be beneficial for repairing complex tissues, such as osteochondral tissue.

Knots Tied With High-Tensile Strength Tape Biomechanically Outperform Knots Tied With Round Suture.

BACKGROUND: Tape-type suture material is well-accepted in arthroscopy surgery. PURPOSE: To compare the knot security of a high-tensile strength round suture and high-tensile strength tape with commonly used arthroscopic knots. STUDY DESIGN: Controlled laboratory study. METHODS: We compared the performance of No. 2 braided nonabsorbable high-strength suture with that of 1.3-mm braided nonabsorbable high-strength tape. Five commonly used arthroscopic knots were investigated: the Roeder knot; the Western knot; the Samsung Medical Center (SMC) knot; the Tennessee knot; and a static surgeon's knot. Seven knots were tied for each combination of knots and suture types. Knots were tied on a 30-mm circumferential metal post, and the suture loops were transferred to a materials testing machine. After preloading to 5 N, all specimens were loaded to failure. The clinical failure load, defined as the maximal force to failure at 3 mm of crosshead displacement, yield load, and stiffness, were recorded. A 2-way analysis of variance was used to determine differences between the groups. RESULTS: Both suture type and knot type significantly affected the clinical failure load, yield load, and stiffness (P = .002). The high-strength tape resulted in a significantly greater clinical failure load than the high-strength suture in the case of the Roeder knot, Western knot, and SMC knot (P = .027, .005, and .016, respectively). When the high-strength round suture was used, the Roeder knot, Western knot, and SMC knot resulted in significantly smaller clinical failure loads compared with the Tennessee knot (P = .011, .003, and .035, respectively) and the static surgeon's knot (P < .001 for all). When the high-strength tape was used, the Roeder knot, Western knot, and SMC knot resulted in significantly smaller clinical failure loads compared with the static surgeon's knot (P = .001, .001, and .003, respectively). CONCLUSION: The results of this study indicated that arthroscopic knots tied using 1.3-mm high-strength tape biomechanically outperformed knots tied using a No. 2 high-strength suture. While the static surgeon's knot exhibited the best biomechanical properties, the Tennessee knot resulted in generally better biomechanical properties among the arthroscopic sliding knots. CLINICAL RELEVANCE: Elongation and loosening of tied knots possibly affects the clinical results of repaired constructs.

Role of open cerclage wiring in patients with comminuted fractures of the femoral shaft treated with intramedullary nails.

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.

"Flip lid" type of lateral tibia plateau fracture with a meniscus radial tear: A case report.

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.

Does posterior configuration have similar strength as parallel configuration for treating comminuted distal humerus fractures? A cadaveric biomechanical study.

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.

Modified Superior Capsule Reconstruction Using the Long Head of the Biceps Tendon as Reinforcement to Rotator Cuff Repair Lowers Retear Rate in Large to Massive Reparable Rotator Cuff Tears.

PURPOSE: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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 OF EVIDENCE: Level III, retrospective therapeutic comparative trial.

Characterization of a Sandwich PLGA-Gallic Acid-PLGA Coating on Mg Alloy ZK60 for Bioresorbable Coronary Artery Stents.

Absorbable magnesium stents have become alternatives for treating restenosis owing to their better mechanical properties than those of bioabsorbable polymer stents. However, without modification, magnesium alloys cannot provide the proper degradation rate required to match the vascular reform speed. Gallic acid is a phenolic acid with attractive biological functions, including anti-inflammation, promotion of endothelial cell proliferation, and inhibition of smooth muscle cell growth. Thus, in the present work, a small-molecule eluting coating is designed using a sandwich-like configuration with a gallic acid layer enclosed between poly (d,l-lactide-co-glycolide) layers. This coating was deposited on ZK60 substrate, a magnesium alloy that is used to fabricate bioresorbable coronary artery stents. Electrochemical analysis showed that the corrosion rate of the specimen was ~2000 times lower than that of the bare counterpart. The released gallic acid molecules from sandwich coating inhibit oxidation by capturing free radicals, selectively promote the proliferation of endothelial cells, and inhibit smooth muscle cell growth. In a cell migration assay, sandwich coating delayed wound closure in smooth muscle cells. The sandwich coating not only improved the corrosion resistance but also promoted endothelialization, and it thus has great potential for the development of functional vascular stents that prevent late-stent restenosis.

Treatment of a rotator cuff tear combined with iatrogenic glenoid fracture and shoulder instability: A rare case report.

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.

The Biomechanical Properties of a High-Tensile Strength Tape for Tendon Graft Fixation Using the Krackow Configuration.

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.

Using Interconnected Knotless Anchor for Suprapectoral Biceps Tenodesis Could Offer Improved Biomechanical Properties in a Cadaveric Model.

PURPOSE: To compare the biomechanical characteristics of the interconnected knotless anchor (IKA) fixation with the double knotless anchor (DKA) and interference screw (IS) fixation in the suprapectoral biceps tenodesis. METHODS: In total, 24 fresh-frozen human cadaveric shoulders (mean age, 67.3 ± 6 years) were used for the study. All the specimens were randomly divided into 3 experimental biceps tenodesis groups (n = 8): IKA, DKA, and IS. After tenodesis, each specimen was preloaded at 5 N for 2 minutes, followed by a cyclic loading test from 5 to 70 N for 500 load cycles. Finally, a destructive axial load to failure test (1 mm/s) was performed. All the values, including ultimate failure load, stiffness, cyclic displacement, and mode of failure were evaluated. RESULTS: The IKA provided the highest construct stiffness (38.9 ± 7.7 N/mm) and ultimate failure load (288.3 ± 47.6 N), the results for which were statistically better than the corresponding results in the IS and DKA groups. In terms of cyclic displacement, there were no statistical differences among the 3 fixation constructs. The most common failure mode was biceps tendon tearing in IS group (7/8) and IKA group (8/8). In the contrast, suture slippage accounted for the most common failure mode in DKA. CONCLUSIONS: In suprapectoral bicep tenodesis, IKA fixation appears to offer improved construct stiffness and ultimate failure load while maintaining comparable suture slippage as compared with IS fixation or DKA fixation in the current biomechanical study. CLINICAL RELEVANCE: The IKA fixation compares favorably with other techniques and could be an alternative clinical option for suprapectoral biceps tenodesis.

Treating AO/OTA 44B lateral malleolar fracture in patients over 50 years of age: periarticular locking plate versus non-locking plate.

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.

The Double Krackow Suture Technique Does Not Offer a Significant Benefit Compared to the Krackow Suture Technique in Subpectoral Biceps Tenodesis Using a Double-Loaded Suture Anchor.

PURPOSE: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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. CLINICAL RELEVANCE: A sturdy suture-tendon structure could prevent clinical failure of a subpectoral biceps tenodesis using a suture anchor.