Evaluating effectiveness of cadaveric arthroscopic training for orthopaedic residents: A comparison of joints and training levels.

Purpose: This study aimed to evaluate the effects and interactions of training level and different joints on the outcomes of cadaveric arthroscopic training courses for orthopaedic residents. Methods: This prospective study enrolled 16 orthopaedic residents who voluntarily participated in a cadaveric training programme involving the shoulder, elbow, wrist, knee and ankle joints. Outcomes were quantitatively assessed using task-specific checklists and the Arthroscopic Surgery Skill Evaluation Tool. Two-way analysis of variance (ANOVA) was conducted to determine the significance of the interactions between joint and years of training. Results: Resident scores significantly increased after the dedicated lectures in all five joints (p = 0.003 for the shoulder module, p < 0.001 for the other joints). Two-way ANOVA revealed that the progress made after the dedicated lectures was significantly impacted by the joint (p = 0.006) and training level × joint interaction (p = 0.005) but not by the training level (p = 0.47). The simple effect of the joint was examined using Sidak's multiple comparison test. Among junior residents, the dedicated lectures resulted in more substantial progress in elbow and wrist arthroscopy when compared to shoulder arthroscopy (p = 0.020 and p = 0.043, respectively). Conclusions: The results suggest that, in cadaveric arthroscopic training courses for orthopaedic residents, training outcomes are primarily impacted by the specific joint being trained rather than the training level. Specifically, junior residents demonstrated greater improvement with training in procedures that are less commonly encountered during on-the-job training, such as elbow and wrist arthroscopy. Clinical Relevance: These findings suggest the need to prioritise wrist and elbow arthroscopic training for junior residents to optimise educational outcomes. Level of Evidence: Level III.

Biomechanical Comparisons of All-Suture Suspensory Button versus Interference Screw for Inlay Subpectoral Bicep tenodesis.

BACKGROUND: All-suture buttons (ASB) and interference screw (IS) are commonly utilized in the inlay subpectoral biceps tendon tenodesis. However, the biomechanical characteristics of these two methods have not been compared directly. The aim of present study was to compare the biomechanical properties of ASB versus IS for inlay subpectoral biceps tendon tenodesis in a human cadaveric model. METHODS: Sixteen fresh-frozen human cadaveric shoulders were randomly divided into two experimental inlay biceps tenodesis groups: ASB or IS. After tenodesis, every specimen was preloaded at 5 N for 2 minutes, followed with a cyclic loading test from 5 to 70 N for 500 load cycles. Then the load-to-failure test was performed. Afterwards, the humerus was placed in a cylinder tube and secured with anchoring cement. Lastly, a two-point bending test was performed to determine the strength of the humerus. Destructive axial force was applied, and the failure strength and displacement were recorded. RESULTS: No difference in stiffness was observed between the two groups (ASB=27.4 ± 3.5 N/mm vs IS= 29.7 ± 3.0 N/mm; P=.270). Cyclic displacement was significantly greater in the ASB group (6.8 ± 2.6 mm) than the IS group (3.8 ± 1.1 mm; P=.021). In terms of failure load, there were no statistical differences among the two groups (P=.234). The ASB group was able to withstand significantly greater displacement (11.9 ± 1.6 mm) before failure than the IS group (7.8 ± 1.5mm; P=.001). During the humeral bending test, the ASB group exhibited significantly greater maximal load (2354.8 ± 285.1 N vs 2086.4 ± 296.1 N; P=.046) and larger displacement (17.8 ± 2.8mm vs 14.1± 2.8 mm; P=.027) before fracture. CONCLUSIONS: In inlay subpectoral bicep tenodesis, ASB fixation appears to offer comparable stiffness and failure load to that of IS fixation. Additionally, the ASB group exhibited greater resistance to load and displacement before humeral fracture. However, the ASB group did demonstrate increased cyclic displacement compared to IS group.

Factors associated with reparability of rotator cuff tears: a systematic review and meta-analysis.

BACKGROUND: To identify and quantify the factors associated with the reparability of rotator cuff tears (RCTs). METHODS: PubMed, Scopus, and Web of Science databases were searched for clinical studies published in English focusing on RCT reparability by using the keywords "rotator cuff tear" and "reparability". A meta-analysis was conducted if ≥3 studies examined the same factor and provided enough data to assess RCT reparability. Quality assessment was completed using the quality assessment of diagnostic accuracy studies tool. RESULTS: Eighteen studies (2700 patients) were enrolled and 26 factors were included in the meta-analysis. The dichotomous variables associated with irreparability were Patte stage 3 (odds ratio (OR): 8.0, 95% confidence interval [CI]: 4.3-14.9), massive tear vs. large tear (OR: 3.1, 95% CI: 1.3-7.2), Goutallier stage for each tendon, and tangent sign (OR: 11.1, 95% CI: 4.3-28.4). The continuous variables associated with irreparability were age (mean difference (MD): 3.25, 95% CI: 1.4-5.1), mediolateral tear size (MD: 12.3, 95% CI: 5.8-18.9), anteroposterior tear size (MD: 10.4, 95% CI: 5.2-15.6), acromiohumeral distance on X-ray (MD: -2.3, 95% CI: -3.0 to -1.6) and magnetic resonance imaging (MD: -1.8, 95% CI: -2.8 to -0.9), and inferior glenohumeral distance on magnetic resonance imaging (MD: 2.2, 95% CI: 1.4-3.0). CONCLUSION: This study revealed that older age, larger tear size, severe fatty infiltration, muscle atrophy, and advanced superior migration of the humeral head were strongly associated with irreparable RCTs. Conversely, clinical symptoms provided limited information for predicting reparability. Additionally, the tangent sign emerged as a powerful and simple tool for individual prediction, and several quantitative scoring systems also proved useful.

Suture Contamination During Arthroscopic Rotator Cuff Repair Is Associated With Significantly Higher Retear Rates in Magnetic Resonance Imaging: A Matched-Pair Analysis.

PURPOSE: To evaluate the correlation between suture contamination and rotator cuff tendon retear after arthroscopic rotator cuff repair. METHODS: Patients undergoing primary arthroscopic rotator cuff repair from April 1, 2020, to September 30, 2022, were enrolled. Those younger than 18 years, with a history of shoulder surgeries or shoulder infection episodes, or who declined participation were excluded. A 5-cm section of the first-cut suture, originating from the anchor eyelet ends, in each rotator cuff repair surgery was subjected to bacteria culture and polymerase chain reaction analysis. Patients with positive culture findings were matched 1:1 to those with negative culture reports based on age, sex, tear size as well as involved tendons, preoperative fatty infiltration grade (Goutallier grade), and preoperative muscle atrophy grade (Warner score). Postoperative rotator cuff tendon retear assessments were conducted at the 6-month mark using the Sugaya classification via magnetic resonance imaging. The Wilcoxon signed-rank test was used for matched-pair comparisons between the groups. RESULTS: A total of 141 patients (60 men and 81 women) with a mean age of 61.0 ± 8 years were finally enrolled. Twenty-six patients (18 men and 8 women) had a positive culture, while 115 patients (42 men and 73 women) had a negative culture. After the propensity score matching process, 24 culture-negative patients (16 men and 8 women) were selected as the culture-negative group. Age, fatty infiltration grade, and muscle atrophy grade were not significantly different between matched groups. The retear grade in the culture-positive group was significantly higher than that in the culture-negative group (P = .020) under the matched-pair comparison. Cutibacterium acnes was the most prevalent bacterial species responsible for suture contamination. CONCLUSIONS: The matched-pair analysis revealed that the presence of bacterial contamination on sutures was associated with a higher risk of retear on magnetic resonance imaging following arthroscopic rotator cuff repair. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Predictors of in-hospital mortality in older patients undergoing distal femur fracture surgery: A case-control study.

INTRODUCTION: Geriatric fractures including distal femur and hip fractures are associated with high mortality rates. Currently, prognostic factors for in-hospital postoperative mortality are not identified. We aimed to evaluate overall in-hospital mortality and related potential risk factors in elderly patients who underwent distal femur fracture surgery. MATERIALS AND METHODS: A retrospective cohort study of patients older than 60 years, who underwent distal femur fracture surgery between January 01, 2003, and December 31, 2021, was conducted. A case-control study was conducted to compare two age-matched groups of elderly patients of equivalent ages at a 1:4 ratio. The in-hospital mortality rate was calculated and potential confounders were compared between groups. RESULTS: A total of 170 patients were enrolled; five died during hospital stay after undergoing surgery, yielding a 2.94% in-hospital mortality rate. Twenty patients who did not die were included in the control group. Patients' demographics were similar. The case-control comparison showed that the time from injury to surgery, preoperative hemoglobin level, estimated glomerular filtration rate (eGFR), and white blood cell count were significant factors correlated with in-hospital mortality. DISCUSSION: The overall in-hospital mortality rate was 2.94%. Significant risk factors for in-hospital mortality included a longer time from injury to surgery, lower preoperative hemoglobin level and eGFR, and higher preoperative white blood cell count. In conclusion, preoperative comprehensive geriatric assessment, including cognitive, nutritional, and frailty status, should also be considered in the elderly fracture care model.

Definition of irreparable rotator cuff tear: a scoping review of prospective surgical therapeutic trials to evaluate current practice.

BACKGROUND: The definition of irreparable rotator cuff tear (IRCT) is controversial. This scoping review provides definitions used to describe IRCT in the literature. This scoping review (1) identified criteria used in the definition of IRCT and (2) investigated the current state of those criteria in prospective surgical therapeutic trials. METHODS: This scoping review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews. PubMed, Scopus, and Web of Science were searched in March 2023. Studies were screened against predetermined inclusion and exclusion criteria. Criteria regarding clinical symptoms, preoperative images, and intraoperative findings were captured respectively. RESULTS: A total of 41 prospective studies were eligible for inclusion, and 35 studies (85.4%) defined IRCT. IRCT was defined on the basis of the following main criteria: preoperative image findings (28/35), intraoperative findings (24/35), and symptoms (16/35). With regard to preoperative images, IRCT was mainly defined on the basis of retraction of the tendon in the coronal plane (22/28), the severity of fatty degeneration (19/28), and ruptured tendon number or width of the defect in the sagittal plane (17/28). CONCLUSION: This scoping review highlights the lack of a standardized definition for IRCT in clinical practice, with common predictive criteria including a duration of over 6 months, retraction beyond 5 cm, Goutallier grade 3 fatty infiltration, and the rupture of two or more tendons. However, surgeons should apply more than one criterion when examining preoperative images and confirm reparability during surgery. A more objective manner of evaluating intraoperative reparability is necessary.

Substantial influence of psychological factors on return to sports after anterior shoulder instability surgery: a systematic review and meta-analysis.

PURPOSE: This systematic review and meta-analysis aimed to (1) determine the proportion of patients who underwent anterior shoulder instability surgery and did not return to sports for psychological reasons and (2) estimate differences in psychological readiness scores between patients who did and did not return to sports. METHODS: The EBSCOhost/SPORTDiscus, PubMed/Medline, Scopus, EMBASE and Cochrane Library databases were searched for relevant studies. The data synthesis included the proportion of patients who did not return to sports for psychological reasons and the mean differences in the psychological readiness of athletes who returned and those who did not return to sports. Non-binomial data were analysed using the inverse-variance approach and expressed as the mean difference with 95% confidence intervals. RESULTS: The search yielded 700 records, of which 13 (1093 patients) were included. Fourteen psychological factors were identified as potential causes for not returning to sports. The rates of return to sports at any level or to the preinjury level were 79.3% and 61.9%, respectively. A total of 55.9% of the patients cited psychological factors as the primary reason for not returning to sports. The pooled estimate showed that patients who returned to sports had a significantly higher Shoulder Instability-Return to Sport After Injury score (P < 0.00001) than those who did not, with a mean difference of 30.24 (95% CI 24.95-35.53; I2 = 0%; n.s.). CONCLUSIONS: Psychological factors have a substantial impact on the rate of return to sports after anterior shoulder instability surgery. Patients who returned to sports had significantly higher psychological readiness than those who did not return to sports. Based on these results, healthcare professionals should include psychological and functional measurements when assessing athletes' readiness to return to sports. LEVEL OF EVIDENCE: Level IV.

Surgical treatment of inferior pole fractures of the patella: a systematic review.

PURPOSE: This study aimed to comprehensively review the existing evidence concerning surgical treatment of inferior pole fractures of the patella and to report the outcomes and complications of different fixation techniques. METHOD: This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Searches of PubMed, Scopus, and Web of Science were conducted in March 2023. Studies were screened against predecided inclusion and exclusion criteria. The extracted data included fracture characteristics, surgical techniques, and radiographic and functional outcomes. The Methodological Index for Non-Randomized Studies (MINORS) quality assessment tool was used to assess the eligible literature. The primary outcome was postoperative range of motion of different surgical methods, and the secondary outcomes were other clinical results and complications. RESULTS: A total of 42 studies satisfied all the inclusion criteria and were deemed suitable for review. Fourteen case-control studies and 28 case series were selected, for a total of 1382 patients with a mean age of 51.0 years (range = 11-90). The follow-up period ranged from 6 to 300 months. The surgical techniques were categorized based on the device used as follows: (1) rigid fixation device; (2) tensile fixation device; (3) mixed device; and (4) extra-patella device. CONCLUSION: Regarding the outcomes following surgical treatment of inferior pole fractures of the patella, the postoperative range of motion (ROM) of each technique ranged from 120° to 135°, with the exception of that involving the patellotibial wire which had poorer outcomes. The lowest functional score was also found in those using the patellotibial wire. Complications after surgery are rare, but approximately half of the patients required additional surgery for implant removal, particularly those whose initial surgery involved rigid fixation devices. It's worth noting that bony fragment excision is no longer recommended, and the combined use of multiple surgical devices is now more common.

Biomechanical comparison of different suture anchors used in rotator cuff repair surgery-all-suture anchors are equivalent to other suture anchors: a systematic review and network meta-analysis.

PURPOSE: Suture anchors are commonly used to repair rotator cuff tendons in arthroscopy surgery, and several anchor materials have been created to maximize pull-out strength and minimize iatrogenic damage. We hypothesized that all-suture anchors have biomechanical properties equivalent to those of conventional anchors. Our purpose is to compare the biomechanical properties of different anchors used for rotator cuff repair. METHODS: The Embase, PubMed, Cochrane, and Scopus databases were searched for biomechanical studies on various suture anchors. The search keywords included rotator cuff tears and suture anchors, and two authors conducted study a selection, risk of bias assessment, and data extraction. The failure load, stiffness, and displacement were calculated using the mean differences with 95% confidence intervals (CIs). Failure modes were estimated using summary odds ratios with 95% CIs. The surface under the cumulative ranking curve was used for the relative ranking probabilities. A sensitivity analysis was performed by excluding studies using synthetic bones. RESULTS: The polyetheretherketone (PEEK) (p < 0.001) and all-suture anchors (p < 0.001) had higher failure loads than the biocomposite anchors, whereas no significant difference was observed in stiffness among the anchors. The all-suture (p = 0.006) and biocomposite anchors (p < 0.001) had displacements higher than the metal anchors. The relative ranking of the included anchors in failure loads and displacement changed in sensitivity analysis. The meta-analysis did not find significant differences, but the relative ranking probabilities suggested that all-suture anchor had a higher rate of anchor pull-out and a lower rate of eyelet or suture breakage. In contrast, the metal anchors were associated with a higher number of eyelet breakage episodes. CONCLUSIONS: All-suture anchors showed significantly higher failure loads than the biocomposite anchors and similar cyclic displacements to the biocomposite and PEEK anchors. There were no significant differences in stiffness between all-suture and conventional suture anchors. The relative ranking of biomechanical properties changed in sensitivity analysis, suggesting the potential effect of bone marrow density. LEVEL OF EVIDENCE: Level IV.

Merged Lateral Row Modification of the Suture Bridge Technique for Simultaneous Supraspinatus and Subscapularis Repair.

Concomitate supraspinatus and subscapularis tear is not rare, and the suture bridge technique is one of the most effective methods for rotator cuff repair. However, some limitations exist in the use of such a technique for simultaneous supraspinatus and subscapularis repair. We introduce the technique of a merged lateral row for suture bridge rotator cuff repair, in which the lateral suture of the supraspinatus and subscapularis is placed in the greater tuberosity. We believe that this technique can reduce both the duration and cost of surgery and decrease soft-tissue damage. It can also allow the "comma tissue," to be simultaneously repaired.

Extended skin cleaning on the shoulder with chlorhexidine reduces the cutaneous bacterial load but fails to decrease suture contamination in patients undergoing arthroscopy rotator cuff repair.

BACKGROUND: It remains unclear whether preoperative skin cleaning of the chin, neck, and chest with chlorhexidine soap can reduce suture contamination by Cutibacterium acnes in patients undergoing arthroscopic rotator cuff repair. METHODS: This study included patients who underwent primary arthroscopic rotator cuff repair. Exclusion criteria included age <18 years, previous shoulder surgery, history of shoulder infection, and allergy to chlorhexidine. Patients were randomized into 3 groups. Patients in the control group cleaned their skin with soap and water, as usual. Patients in the shoulder group cleaned their shoulders with chlorhexidine soap 3 days before surgery, whereas patients in the extended shoulder group additionally cleaned their chest, back, neck, and face with chlorhexidine soap. On the day of surgery, skin swab samples were obtained from the shoulder after surgical draping. After rotator cuff repair, sutures were cut from the anchor ends. Both traditional culture methods and polymerase chain reaction (PCR) were used. RESULTS: Ninety patients were enrolled (32 in the control group, 29 in the shoulder group, and 29 in the extended shoulder group) in the present study. The culture-positive rate from the posterior shoulder skin samples in the extended shoulder group (17.2%) was significantly lower than that in the control (40.6%) and shoulder (48.3%) groups (P = .036), whereas the culture-positive rates were not different among the 3 groups in other skin samples as well as the suture samples. The detection rates of C acnes in suture samples were 12.5%, 13.8%, and 17.2% in the control, shoulder, and extended shoulder groups, respectively (P = .603). CONCLUSION: Extensive skin cleaning of the shoulder region with chlorhexidine helps reduce the shoulder cutaneous bacterial load, but the detection of C acnes suture contamination in patients undergoing arthroscopic rotator cuff repair remained untouched regardless of the use of chlorhexidine soap in skin cleaning on the preoperative days.

Morphometric and Biomechanical Comparison of the Scapular Spine and Coracoid Graft in Anterior Shoulder Instability.

BACKGROUND: The scapular spine has been described as a relatively new bone graft alternative used in glenoid augmentation. The classic Latarjet procedure, which transfers the coracoid as a graft, is regarded as the gold standard. The comparison of these 2 techniques has not been fully reported. PURPOSE: To compare the anatomic and biomechanical properties of glenoid augmentation using scapular spine graft or coracoid graft. STUDY DESIGN: Controlled laboratory study. METHODS: The study used 20 fresh-frozen human cadaveric shoulders. A 25% anterior glenoid defect was created, and the specimens were divided randomly to receive glenoid augmentation by scapular spine or coracoid grafts. For both procedures, the grafts were secured to the glenoid defect with 2 screws. Morphometric data, including the glenoid articular area, amount of restoration, and graft dimensions, were obtained. A biomechanical test was conducted in a direct-loading scenario. The construct stiffness, cyclic displacement, and ultimate failure of each specimen were collected. RESULTS: No significant difference was found in glenoid articular restoration between the scapular spine group and the coracoid group (31% vs 33%, respectively; P = .311). Morphometric analysis indicated that coracoid grafts exhibited significantly greater thickness and height than scapular spine grafts. In biomechanical results, the scapular spine group exhibited significantly greater construct stiffness than the coracoid group (206.3 ± 58.8 vs 148.3 ± 76.0 N/mm, respectively; P = .023). The average failure load in the scapular spine group was not significantly higher than that in the coracoid group. No significant differences in cyclic displacement were found between the 2 techniques. CONCLUSION: In a simulated 25% anterior glenoid bony defect, a scapular spine graft was comparable with the classic Latarjet procedure in restoring the glenoid articular dimension and exhibited superior construct stiffness in a cadaveric model. CLINICAL RELEVANCE: The scapular spine may serve as an alternative graft choice in glenoid augmentation surgery considering the amount of articular restoration and initial fixation stability.

A Study on the Structure and Biomedical Application Characteristics of Phosphate Coatings on ZKX500 Magnesium Alloys.

Magnesium-matrix implants can be detected by X-ray, making post-operative monitoring easier. Since the density and mechanical properties of Mg alloys are similar to those of human bones, the stress-shielding effect can be avoided, accelerating the recovery and regeneration of bone tissues. Additionally, Mg biodegradability shields patients from the infection risk and medical financial burden of needing another surgery. However, the major challenge for magnesium-matrix implants is the rapid degradation rate, which necessitates surface treatment. In this study, the ZKX500 Mg alloy was used, and a non-toxic and eco-friendly anodic oxidation method was adopted to improve corrosion resistance. The results indicate that the anodic coating mainly consisted of magnesium phosphate. After anodic oxidation, the specimen surface developed a coating and an ion-exchanged layer that could slow down the degradation and help maintain the mechanical properties. The results of the tensile and impact tests reveal that after being immersed in SBF for 28 days, the anodic oxidation-treated specimens maintained good strength, ductility, and toughness. Anodic coating provides an excellent surface for cell attachment and growth. In the animal experiment, the anodic oxidation-treated magnesium bone screw used had no adverse effect and could support the injured part for at least 3 months.

The characteristics and influence of iatrogenic fracture comminution following antegrade interlocking nailing for simple femoral shaft fractures, a retrospective cohort study.

AIM: The incidence and characteristics of iatrogenic comminution (IC) are unknown, and the influence of IC on fracture union is unclear. This study was aimed to investigate the (1) incidence and characteristics of IC and (2) the outcomes of IC following antegrade interlocking nailing of simple femoral shaft fractures. METHODS: We retrospectively collected data on patients who experienced simple femoral shaft fractures and underwent antegrade interlocking nailing between February 2009 and December 2016. The incidence and characteristics of IC were examined. According to the presence of IC, patients were divided into two groups: an IC group and a non-IC (NIC) group. Demographic information and nonunion rates were compared between the two groups. Potential risk factors for IC (age, gender, body mass index (BMI), nail fit ratio, reduction technique, and greater trochanter nail entry) were analyzed using univariate and multivariate logistic regression. The aforementioned variables, along with IC occurrence, were also assessed as potential risk factors for nonunion at 12 and 24 months after operation using multivariate logistic regression. RESULTS: Of the 211 total patients, IC occurred in 20.9% (n = 44) of patients. Most ICs were found at the level of the isthmus, and involved the medial cortex. Compared with the NIC group, higher nonunion rates were observed in the IC group at 12 months (31.8% vs. 12.5%, p = 0.002) and 24 months (18% vs. 6.5%, p = 0.017) after surgery. Age older than 35 years old was related with the occurrence of IC in univariate analysis. Multivariate analysis found no risk factor associated with IC. Open reduction technique, IC occurrence and higher BMI were identified as the risk factors of nonunion at 12 months and 24 months after surgery in multivariate analysis. CONCLUSION: IC is a non-rare complication in antegrade interlocking nailing of simple femoral shaft fractures and was associated with higher nonunion rate. Age older than 35 years old showed a trend toward increasing risk of iatrogenic fracture comminution. In multivariate analysis, open reduction technique, IC occurrence and higher BMI significantly correlated with fracture nonunion. LEVEL OF EVIDENCE: Level IV.

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.

Does Weaver-Dunn procedure have a role in chronic acromioclavicular dislocations? A meta-analysis.

BACKGROUND: In treatment of chronic acromioclavicular (AC) joint dislocations, both the Weaver-Dunn procedure (WD) and CC ligament reconstruction (CCR) are recommended options due to the low possibility of healing of the coracoclavicular (CC) ligaments. The aim of this review was to determine whether CCR will yield favorable clinical and radiographic outcomes in the treatment of chronic AC dislocations. METHOD: The Cochrane Library, EMBASE, and PubMed databases were searched for literature on chronic AC dislocations from data inception to June 30, 2021. Patient data were pooled using standard meta-analytic approaches. The Cochrane-Mantel-Haenszel method and variance-weighted means were used to analyze the outcomes. The Review Manager version 5.3 software (The Nordic Cochrane Centre, The Cochrane Collaboration, Copenhagen, Denmark) was used to calculate the heterogenicity, mean difference, and relative risk (RR) for all outcomes in the meta-analysis. RESULTS: The current analysis included four trials on this topic, and all AC joint dislocations were classified as Rockwood types III to VI. The pooled data showed that the CCR group had significantly better post-operative American Shoulder and Elbow Surgeons Shoulder (ASES) scores, Oxford Shoulder Scores (OSSs), and Nottingham Clavicle Scores (NCSs) than the WD group, with a significant difference (p < 0.001, p = 0.020, and p < 0.001, respectively). In terms of the post-operative Constant-Murley Scores (CMSs), there were no significant differences between the CCR group and the WD group (p = 0.100). The CCR group had significantly better post-operative abduction and flexion of the index shoulder than the WD group (p < 0.001 and p < 0.001, respectively). In terms of radiological outcomes, the post-operative coracoclavicular distance (CCD) with a 10 kg load was smaller in the CCR group compared to that in the WD group (p < 0.001). The overall surgical wound infection rate was 11.6% in the WD group and 12.9% in the CCR, respectively (p = 0.82). CONCLUSION: The CCR group had better clinical outcome scores in the ASES, OOS, NCS, abduction, flexion, and external rotation than the WD group. In terms of radiological outcomes, the CCR group showed less displacement in weight-loaded post-CCD than the WD group, which indicated that the CCR provided more stability and resistance to deformation forces.

Biomechanical comparisons of hook plate and screw fixations in split-type greater tuberosity fractures of the humerus.

BACKGROUND: Screws and plate are commonly utilized for the fixation of split-type humeral greater tuberosity (GT) fractures. However, the mechanical properties of these 2 types of fixation methods have not been compared directly. The aim of the present study was to evaluate the classic 2 screws fixation with hook locking plate from a mechanical perspective. METHODS: Sixteen synthetic humerii (Sawbones Pacific Research Laboratories, Vashon, WA, USA) were divided into 2 groups. An osteotomy was performed to simulate a split-type GT fracture. Group A (n = 8) was fixed with 2 standard parallel screws. Group B (n = 8) was fixed with a hook plate. Each specimen was tested with traction force at 45° shoulder abduction. Following the 20-N preload, a 500-cycle loading test was applied with a force ranging from 20 to 200 N (valley/peak), and the interfragmental displacement was measured periodically at intervals of 100 cycles. Finally, all the specimens were pulled with destructive force at a rate of 5 mm/min until catastrophic failure. RESULTS: The hook plate exhibited greater construct stiffness than the screw fixation (63.2 ± 6.1 N/mm vs. 40.9 ± 3.4 N/mm, P < .001). All of the specimens completed the entire cyclic loading test without catastrophic failure, and the fragment displacement after 500 cycles was 0.4 ± 0.2 mm for the hook plate and 2.1 ± 0.3 mm for screw fixation, which was statistically lower in the plate group (P < .001). In terms of failure load, the hook plate group exhibited a significantly greater value than the screw group (770.6 ± 94.6 vs. 427.5 ± 45.1 N/mm, P < .001). The failure modes of both fixation methods were distinct. CONCLUSION: In humeral GT fracture fixation, hook plate fixation appears to offer greater construct stiffness and failure load while maintaining fragment stability to resist a physiological traction force. The current study provides support from a mechanical perspective for the clinical application of the hook plate.

Adult patients with ACL tears have greater tibial internal rotation in MRI compared to adolescent patients.

PURPOSE: To compare the anterior translation and internal rotation of tibia on magnetic resonance imaging (MRI) between adult and adolescent patients with anterior cruciate ligament (ACL) tears. METHODS: Patients who underwent isolated ACL reconstruction from January 2013 to May 2021 were retrospectively reviewed. The exclusion criteria included incomplete data, poor image quality, a prior ACL surgery, and concomitant fractures or other ligament injuries. The enrolled patients were divided into two groups based on their ages: an adult group (age > 19 years) and an adolescent group (15 to 19 years of age). Anterior tibial translation and femorotibial rotation were measured on MRI. A Student's t-test was used for the statistical analysis comparing the adult and adolescent groups. RESULTS: A total of 365 patients (279 adults and 86 adolescents) were enrolled in the present study. The anterior tibial translation in the adult group (4.8 ± 4.4 mm) and the adolescent group (5.0 ± 4.2 mm) was not significantly different (p = 0.740). On the other hand, the tibial internal rotation in the adult group (5.6 ± 5.0 degree) was significantly greater compared to the adolescent group (4.2 ± 5.6 degree) (p = 0.030). The intraclass correlation coefficients (ICC) of the measured data from two independent observers showed excellent reliability (0.964 and 0.961 for anterior tibial translation and tibial internal rotation, respectively). CONCLUSION: The adult patients with ACL tears exhibited significant greater tibial internal rotation compared to the adolescent patients, whereas the magnitude of the anterior tibial translation was similar in both groups. Care should be taken if clinicians plan to establish the cutoff point values for diagnosis of ACL tears using the femorotibial internal rotation angle.

Owen, Sugaya, and Hayashida Classifications Give Poor Intra- and Inter-Rater Agreement on a Magnetic Resonance Imaging Evaluation of Subscapularis Tendon Retears.

PURPOSE: To investigate the intra- and inter-rater agreements for magnetic resonance imaging (MRI) evaluations of subscapularis tendon integrity at 6 months after arthroscopic rotator cuff repairs. METHODS: Patients who had isolated or combined subscapularis tears and had undergone arthroscopic rotator cuff repairs were retrospectively included. The exclusion criteria included revision of arthroscopic surgery, minor subscapularis tears without repair, and inadequate postoperative images. MRI scans 6 months after surgery were used for the purpose of accessing the integrity of the subscapularis tendons. Three orthopaedic surgeons blindly evaluated the images twice at 2-week intervals. Three currently available classifications were used: the Owen classification, the Sugaya classification, and the Hayashida classification. Dichotomization and trichotomization methods were used for the Sugaya classification and Hayashida classifications. The aforementioned classification scores were combined for the agreement evaluation. Intra- and inter-rater agreement was assessed by calculating the Fleiss' kappa coefficients. RESULTS: A total of 35 patients were included. Both the Owen and Hayashida classifications had poor inter-rater agreements (κ = 0.10 and 0.04, respectively) and poor-to-weak intra-rater agreements (κ = 0.27-0.44 and 0.16-0.45, respectively). The Sugaya classification had poor inter-rater agreement (κ = 0.10) and poor intra-rater agreements (κ = 0.16-0.32). Dichotomization and trichotomization of Sugaya and Hayashida classifications did not lead to superior agreements. The classification combination resulted in poor inter- and intra-rater agreements (κ = 0.01-0.12 and 0.08-0.39, respectively). CONCLUSIONS: The Owen classification, Sugaya classification, and Hayashida classification had poor intra- and inter-rater agreement in terms of evaluating subscapularis tendon re-tears on 6 months' postoperative MRI. The dichotomized and trichotomized classifications as well as the combined classifications from currently available classifications did not lead to superior agreements. LEVEL OF EVIDENCE: Level IV, diagnostic: case series.