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OBJECTIVE: The nucleus pulposus (NP) of the intervertebral disc develops from the notochord. Humans and other species in which notochordal cells (NCs) disappear to be replaced by chondrocyte-like mature NP cells (MNPCs) frequently develop disc degeneration, unlike other species that retain NCs. The reasons for NC disappearance are unknown. In humans, the change in cell phenotype (to MNPCs) coincides with changes that decrease nutrient supply to the avascular disc. We undertook this study to test the hypothesis that the consequent nutrient stress could be associated with NC disappearance. METHODS: We measured cell densities and metabolic rates in 3-dimensional cultures of porcine NCs and bovine MNPCs, and we determined survival rates under conditions of nutrient deprivation. We used scanning electron microscopy to examine end plate porosity of discs with NCs and those with MNPCs. Nutrient-metabolite profiles and cell viability were calculated as a function of cell density and disc size in a consumption/diffusion mathematical model. RESULTS: NCs were more active metabolically and more susceptible to nutrient deprivation than were MNPCs. Hypoxia increased rates of glycolysis in NCs but not in MNPCs. Higher end plate porosity in discs with NCs suggested greater nutrient supply in keeping with higher nutritional demands. Mathematical simulations and experiments using an analog disc diffusion chamber indicated that a fall in nutrient concentrations resulting from increased diffusion distance during growth and/or a fall in blood supply through end plate changes could instigate NC disappearance. CONCLUSION: NCs demand more energy and are less resistant to nutritional stress than MNPCs, which may shed light on the fate of NCs in humans. This provides important information about prospective NC tissue engineering approaches. [ABSTRACT FROM AUTHOR]

Background: For degenerative shoulder disease, reverse shoulder arthroplasty (RSA) has proven successful; however, problems such as scapular notching and instability still exist. These difficulties are intended to be addressed by recently improved prosthesis designs with reduced neck-shaft angles (NSA). Still, there are issues with complications, particularly with the humerus. In an effort to avoid these problems and maintain bone stock, a recently designed straight-short-stem humeral component was used; however, yet its clinical and radiological outcomes in RSA remain largely unexplored., Material and Methods: Using a 55 mm straight short stem (Comprehensive Reverse Shoulder System; Zimmer Biomet), a retrospective analysis of 93 patients undergoing primary RSA was carried out. Clinical assessments, including scores and range of motion, were conducted both before and after surgery. Complications, bone adaptation, and stem alignment were all evaluated radiographically. Significant correlations between postoperative shoulder movements and function were linked with angles of prosthesis lateralization and distalization., Results: Patients demonstrated significant improvements in clinical scores at 35-month follow-up on average: Constant-Murley (76.4 ± 13.4), American Shoulder and Elbow Surgeons (84.8 ± 16.5), Disabilities of Arm, Shoulder, the Hand (17.1 ± 15.8), and University of California and Los Angeles (7.1 ± 1.5). Radiographic assessments showed no stem loosening and stable implant attachment. There was no scapular notching, and there were noticeable improvements in shoulder range of motion and function., Discussion and Conclusion: This study validates the efficacy of a straight short stem for acceptable clinical outcomes and implant stability in RSA. Notably, it demonstrates specific angle ranges crucial for optimal postsurgical shoulder function. The findings suggest this stem design presents potential benefits in RSA, highlighting its safety and effectiveness while providing insights for future clinical strategies. The study contributes valuable data toward understanding and enhancing patient outcomes in shoulder arthroplasty procedures., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Objectives: The purposes of this study were to assess clinical and radiographic outcomes following plate-assisted bone segment transport (PABST) in large bone defects of the lower extremities., Design: Retrospective study of prospectively collected data., Setting: Level-1 trauma center located in Germany., Patient Selection Criteria: Patients who underwent PABST and were at least 1 year postoperatively were included., Outcome Measures and Comparisons: Demographic data were collected. Radiographic apparent bone gap (RABG), time to consolidation, time to full weight-bearing, and consolidation index were calculated. Numeric rating scale, lower extremity functional scale (LEFS), and complications were assessed., Results: Fifteen patients [13 male; mean age 51 years (range, 20-75)] underwent PABST and had follow-up at a mean of 29.1 months. The tibia was affected in 8 and the femur in 7 patients. Preoperative RABG was 60 mm [interquartile range (IQR): 40-125], and bone defects were caused by septic nonunions in 73% of patients. Fourteen patients (93%) demonstrated consolidated transport callus at 7.3 months [95% confidence interval (95% CI), 6-8.5], and 9 patients (60%) demonstrated complete consolidation of both docking site and transport callus at 11.5 months (95% CI, 7.3-15.3). Postoperative RABG was 0.1 mm (IQR: 0-0.8), and consolidation index was 1.9 months/cm (95% CI, 1.3-2.5). All patients achieved full weight-bearing at 8.7 months (IQR: 6.5-10.3). LEFS was 42 (95% CI, 34-50), and numeric rating scale was 3 (95% CI, 2-4). Patients treated for tibial defects had a significantly higher consolidation rate compared with patients treated for femoral defects ( P = 0.040)., Conclusions: PABST demonstrated high consolidation of transport callus with few complications. Although full weight-bearing was achieved in all patients, complete consolidation of the docking site was only present in 60% of cases., Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence., Competing Interests: The authors report no conflict of interest., (Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc.)

Background: Glenoid defects can be addressed traditionally by asymmetric reaming or by bone-preserving correction to a more lateral joint line by bone or metal augmented baseplates in reverse shoulder arthroplasties. While there is more evidence in literature regarding the outcome and complications of Bony Increased Offset Reversed Shoulder Arthroplasty (BIO-RSA), there is minimal reported experience with the outcome after metal glenoid augments. The aim of this study was to determine whether a metal augment can correct the glenoid deformity in an anatomic manner., Methods: Glenoid morphology and deformity were determined in 50 patients with Walch type B1, B2, D and Favard type E0-E3 glenoid defects using preoperative radiographic and computed tomography (CT) analysis. All patients received a preoperative planning CT with 3D planning, and measurements of glenoid inclination (in 3 planes proximal, middle, distal), reversed shoulder arthroplasty angle (RSA) and glenoid version were obtained. All patients had a pathologic inclination in the coronal or frontal planes of > 10°. Above the threshold of 10° pathological glenoid version or inclination metal hemi-augments of 10°, 20°, or 30° were used which allow an individual 360° augment positioning according to the patient glenoid deformity., Results: The mean preoperative numbers of the glenoid version demonstrate that most glenoids were in retroversion and superior inclination. In total 2410° wedges, 1820° wedges and 8 30° wedges were used. In the majority of cases, the wedge was positioned posteriorly and/or cranially between 10:00 and 12:00 o'clock, which allows a correction in a 3D manner of the glenoid inclination and version. The mean RSA angle could be corrected from 22.76 ± 6.06 to 0.19° ± 2.7 (p < 0.0001). The highest retroversion of the glenoid is evidenced in the proximal section and it could be corrected from - 23.32° ± 4.56 to - 6.74° ± 7.75 (p < 0.0001) and in the middle section from - 18.93° ± 3.35 to - 7.66° ± 5.28 (p < 0.0001). A mean sphere bone overhang distance (SBOD) of 5.70 ± 2.04 mm was found in order to avoid or minimize relevant scapular notching., Conclusion: By using a new 360° metal-augmented baseplate, the preoperative pathological inclination and retroversion can be corrected without medialization of the joint line. Future clinical results will show whether this bone-preserving procedure improves also the clinical outcomes as compared to asymmetric medialized reaming or wedged BIO-RSA., Level of Evidence: Level IV, Case series., (© 2023. The Author(s).)

Introduction: The interval slide procedure (IS) has been introduced to improve mobility in massive, retracted rotator cuff tears. As clinical studies showed controversial results, the benefit of the IS is still widely discussed., Aim: Aim of this study was to analyze the effect of IS procedure on tendon mobility in a fresh porcine cadaver model., Materials and Methods: In 30 fresh porcine cadaver shoulders with artificial supraspinatus defect tendon mobility was tested by measuring the load (in N) during tendon reduction to the footprint at the greater tubercle using a sensor enhanced arthroscopic grasper (t1). In intervention group (N = 15) anterior IS (t2), posterior IS (t3) and intraarticular capsule release (t4) were successively performed, each followed by tendon mobility assessment. Tendon mobility of the control group (N = 15) was measured in same time schedule without intervention., Results: Mobility did not differ between groups for native tendons (CG 28.0 ± 11.2 N vs. IG 26.6 ± 11.6 N; P = 0.75). IS procedure significantly improves mobility at about 25.2% (t1 26.6 ± 11.6 N vs. t4 19.9 ± 12.3 N; P < 0.001) compared to the native tendon and 34.1% compared to CG (CG 30.2 ± 13.7 N vs. 19.9 ± 12.3 N; P = 0.026). In posthoc analyzes, anterior IS (P < 0.001) and capsule release (P = 0.005) significantly increased mobility, whereas the posterior IS did not (P = 0.778)., Conclusion: The IS procedure results in increased supraspinatus tendon mobility in fresh porcine cadaver shoulders. However, performing the posterior IS subsequent to the anterior IS no significant improvement of mobility has been observed., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The treatment of non-unions is often complicated by segmental bone defects and bacterial colonization. Because of the limited availability of autologous bone grafts, tissue engineering focuses on antibiotic-loaded bone graft substitutes. HACaS+G is a resorbable calcium sulphate-hydroxyapatite loaded with gentamicin. The osteoinductive, osteoconductive, and anti-infective effect of HACaS+G has already been demonstrated in clinical studies on patients with chronic osteomyelitis. However, especially for the treatment of infected non-unions with segmental bone defects by HACaS+G, reliable clinical testing is difficult and sufficient experimental data are lacking. We used an already established sequential animal model in infected and non-infected rat femora to investigate the osteoinductive, osteoconductive, and anti-infective efficacy of HACaS+G for the treatment of infected non-unions. In biomechanical testing, bone consolidation could not be observed under infected and non-infected conditions. Only a prophylactic effect against infections, but no eradication, could be verified in the microbiological analysis. Using µ-CT scans and histology, osteoinduction was detected in both the infected and non-infected bone, whereas osteoconduction occurred only in the non-infected setting. Our data showed that HACaS+G is osteoinductive, but does not have added benefits in infected non-unions in terms of osteoconduction and mechanical bone stability, especially in those with segmental bone defects.

(1) Many biomechanical studies are performed using fresh frozen cadavers or embalmed specimens, although the biomechanical characteristics do not match the characteristics of in vivo tendons. Therefore, a fresh in vivo-like cadaver model has been introduced recently. As a limitation for studies with fresh cadavers, rigor mortis must be considered. The aim of this study was to evaluate the impact of the biomechanical properties and time of occurrence of rigor mortis in a fresh cadaver model. (2) For this study, 15 fresh porcine cadaver shoulders were used in an established biomechanical in vitro model to evaluate the onset of rigor mortis . Measurements took place at ten points of time (t1-t10) beginning 103 min post mortem (pm). The mobility of the supraspinatus tendon was measured in Newton (N) with a modified sensor-enhanced arthroscopic grasper. (3) The mean load measured at the time point t1 was 28.0 ± 11.2 N. The first significant decrease of mobility occurred 151 min post mortem (t4) at a mean load of 30.2 ± 13.7 N. From 227 min pm to 317 min pm, there was no further significant increase. (4) Tendon mobility decreases significantly within the first three hours after the killing. Therefore, reliable results can be obtained within 150 min post mortem before the onset of rigor mortis alters the biomechanical properties.

Background: This study aimed to evaluate clinical, cosmetic, and strength midterm outcomes in arthroscopic biceps tenotomy and subpectoral biceps tenodesis using bicortical endobutton and interference screw., Methods: In this retrospective study, inclusion criteria were long head of the biceps (LHB) pathologies treated either with tenotomy or an additional tenodesis. Postoperative assessment included Long Head of Biceps Score (LHBS), age-adjusted Constant-Murley Score, and Subjective Shoulder Value. Elbow flexion and forearm supination strength were measured. The presence of Popeye sign, cramps, and tenderness over the bicipital grove was evaluated. Statistical analysis of continuous variables without normal distribution was performed using Mann-Whitney U test. Grouped analysis was performed using 2-way analysis of variance. Binominal data were analyzed using chi-square test., Results: A total of 73 patients with a mean age of 63.1 ± 9.6 years and a mean follow-up of 4.2 ± 0.5 years were included. Tenotomy was performed in 34 and tenodesis in 39 patients. Tenodesis group displayed a significantly higher LHB score ( P  = .0006), but no significant differences were detected for the age-adjusted Constant-Murley Score and Subjective Shoulder Value. Tenodesis group showed a significantly lower rate of Popeye deformities ( P  = .0007) and tenderness over the bicipital groove ( P  = .004). Patients from the tenotomy group with biceps deformity showed a significantly higher mean contralateral supination strength ( P  = .002) but no significant difference in contralateral elbow flexion compared with patients without biceps deformity. There was one (1.4%) complication in the tenotomy group (postoperative shoulder stiffness)., Conclusion: Both techniques resulted in comparable outcome scores on preselected patients, with tenodesis leading to better LHB function. Tenodesis did not improve elbow flexion and forearm supination strength beyond the tenotomy; however, it reduced the frequency of biceps deformities and tenderness over the bicipital groove. Patients with a strong contralateral forearm supination strength could be at risk of developing a biceps deformity after tenotomy., (© 2022 The Authors.)

The treatment of infected and non-infected non-unions remains a major challenge in trauma surgery. Due to the limited availability of autologous bone grafts and the need for local anti-infective treatment, bone substitutes have been the focus of tissue engineering for years. In this context, bioactive glasses are promising, especially regarding their anti-infective potential, which could reduce the need for local and systemic treatment with conventional antibiotics. The aim of this study was to investigate the osteoinductive and osteoconductive effects, as well as the anti-infectious potential, of S53P4 using a standardized non-union model, which had not been investigated previously. Using an already established sequential animal model in infected and non-infected rat femora, we were able to investigate bioactive glass S53P4 under realistic non-union conditions regarding its osteoinductive, osteoconductive and anti-infective potential with the use of µCT scans, biomechanical testing and histological, as well as microbiological, analysis. Although S53P4 did not lead to a stable union in the non-infected or the infected setting, µCT analysis revealed an osteoinductive effect of S53P4 under non-infected conditions, which was diminished under infected conditions. The osteoconductive effect of S53P4 remained almost negligible in histological analysis, even 8 weeks after treatment. Additionally, the expected anti-infective effect could not be demonstrated. Our data suggested that S53P4 should not be used in infected non-unions, especially in those with large bone defects.

Background: The benefits of the interval slide (IS) procedure in retracted rotator cuff tears remain controversial., Purpose: The purpose was to evaluate the effect of the IS procedure on repair tension (RT). It was hypothesized that the IS procedure (anterior IS [AIS], posterior IS [PIS], and intra-articular capsular release [CR]) would reduce the RT of a supraspinatus tendon., Study Design: Controlled laboratory study., Methods: A total of 31 Thiel-embalmed human cadaveric shoulders (mean age, 74 years; range, 68-84 years) were tested. Full-thickness supraspinatus tendon tears were created, and 1 cm of tendon was resected to simulate a retracted defect. Shoulders were randomized into intervention (n = 16) and control (n = 15) groups. In all shoulders, the load during tendon reduction to footprint was measured, an endpoint was defined as maximum tendon lateralization before 50 N was reached, and the RT (load during lateralization to endpoint) of the native tendon (t 1 ) was evaluated. In the intervention group, AIS (t 2 ), PIS (t 3 ), and CR (t 4 ) were performed in order, with RT measurement after each step. In the control group, RT was assessed at the same time points without the intervention., Results: A complete reduction of the tendon was not achieved in any of the shoulders. Mean maximum lateralization was 6.7 ± 1.30 mm, with no significant differences between groups. In the intervention group, the overall IS procedure reduced RT about 47.0% (t 1 vs t 4 : 38.7 ± 3.9 vs 20.5 ± 12.3 N; P < .001). AIS reduced RT significantly (t 1 vs t 2 : 38.7 ± 3.9 vs 27.4 ± 10.5 N; P < .001), whereas subsequent PIS (t 2 vs t 3 : 27.4 ± 10.5 vs 23.2 ± 12.4 N; P = .27) and CR (t 3 vs t 4 : 23.2 ± 12.4 vs 20.5 ± 12.3 N; P = .655) did not additionally reduce tension. Comparison between groups at t 4 revealed a reduction of RT of about 47.8% (control vs intervention: 39.3 ± 4.0 vs 20.5 ± 12.3 N; P < .001)., Conclusion: The IS procedure reduces RT of the supraspinatus tendon in human cadaveric shoulders. However, performing PIS and CR subsequent to AIS does not reduce tension additionally., Clinical Relevance: These findings provide surgeons with a biomechanical rationale regarding the efficacy of the IS procedure., Competing Interests: The authors declared that they have no conflicts of interest in the authorship and publication of this contribution. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto., (© The Author(s) 2022.)

To compare outcomes, complications, revisions, and rates of implant removal of superior compared to anteroinferior plating in displaced midshaft clavicle fractures at mid-term follow-up. We retrospectively reviewed 79 patients who underwent operative treatment for displaced midshaft clavicle fractures (Group A: 28 patients with superior plating; Group B: 51 patients with anteroinferior plating) that were at least 2 years postoperatively. Adjusted Constant Score (aCS), Visual Analog Scale (VAS), and Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH) score were compared. Bone union, implant removal, complications and revision surgeries were assessed. Group A had a significantly higher aCS compared to group B (90, IQR: 85.0-91.0 vs. 91, IQR: 90.0-93.0; P = 0.037). No significant differences between groups were seen in VAS (P = 0.283) and QuickDASH (P = 0.384). Bone union was achieved in 76 patients (96.2%) with no significant differences between groups (Group A: 96.4% vs. Group B: 96.1%; P > 0.999). There were no significant differences in implant removal rates (Group A: 60.7% vs. Group B: 66.7%; P = 0.630), complications (Group A: 46.4% vs. Group B: 31.4%; P = 0.226) and revisions (Group A: 25% vs. Group B: 9.8%; P = 0.102). Superior and anteroinferior plating result in high bone union rates and good clinical outcomes with similar rates of plate removal., (© 2021. The Author(s).)

Introduction: The aim of the present study was to analyze the injury pattern and thus the dislocation mechanism after simple elbow dislocation using radiographs and magnetic resonance imaging (MRI) data sets., Materials and Methods: The MRI data sets of 64 patients with a mean age of 44 years (18-77 years) were analyzed retrospectively. The inclusion criteria for the study were (1) radiograph with confirmed simple elbow dislocation, (2) low-energy trauma, (3) MRI of the affected elbow ≤ 3 weeks after trauma. The dislocation direction was determined using radiographs. The integrity of the lateral collateral ligament complex (LCLC), common extensor origin (CEO), anterior capsule (AC), medial collateral ligament (MCL), and common flexor origin (CFO) as well as the joint congruity were assessed based on MRI., Results: 34 patients (53%) had a posterolateral, 26 patients (41%) a posterior, and 4 patients (6%) a posteromedial dislocation. LCLC and AC were affected in 64 out of 64 patients (100%). MCL was affected in 58 patients (91%). CEO were affected in 25 patients (39%) and the CFO in 20 patients (31%). In 11 patients (17%) the injury pattern was more pronounced medially than laterally (MCL, CFO, LCLC), with 2 of these patients exhibiting only a partial LCLC tear. All cases with joint incongruency (n = 12, 19%) showed CEO and/or CFO involvement., Conclusions: Simple elbow dislocation leads to a very heterogeneous spectrum of soft tissue injury pattern. A small proportion of patients showed medially pronounced injury patterns. These findings strongly indicate existence of a "reversed Horii circle" with an underlying valgus mechanism (medial force induction) originating and continuing from medial to anterior., (© 2020. The Author(s).)

Non-unions continue to present a challenge to trauma surgeons, as current treatment options are limited, duration of treatment is long, and the outcome often unsatisfactory. Additionally, standard treatment with autologous bone grafts is associated with comorbidity at the donor site. Therefore, alternatives to autologous bone grafts and further therapeutic strategies to improve on the outcome and reduce cost for care providers are desirable. In this study in Sprague-Dawley rats we employed a recently established sequential defect model, which provides a platform to test new potential therapeutic strategies on non-unions while gaining mechanistic insight into their actions. The effects of a combinatorial treatment of a bone graft substitute (HACaS+G) implantation and systemic PTH administration was assessed by µ-CT, histological analysis, and bio-mechanical testing and compared to monotreatment and controls. Although neither PTH alone nor the combination of a bone graft substitute and PTH led to the formation of a stable union, our data demonstrate a clear osteoinductive and osteoconductive effect of the bone graft substitute. Additionally, PTH administration was shown to induce vascularization, both as a single adjuvant treatment and in combination with the bone graft substitute. Thus, systemic PTH administration is a potential synergistic co-treatment to bone graft substitutes.

Background: The purposes of this study were (1) to report functional outcomes; (2) to assess complications, revisions, and survival rate; and (3) to assess differences in functional outcomes between removed and retained radial head arthroplasties (RHAs), early and delayed treatment, and type of RHA used at long-term follow-up after monopolar RHA for unreconstructible radial head fractures or their sequelae., Methods: Seventy-eight patients (mean age, 59.2 years) who were at least 6 years postoperatively after monopolar RHA for unreconstructible RHFs or their sequelae were included. The Mayo Elbow Performance Score (MEPS); Quick Disability of the Arm, Shoulder, and Hand (QuickDASH) score; visual analog scale; postoperative satisfaction (1-6, 6 = highly unsatisfied); range of motion; complications; and revisions were assessed. Radiographic findings were reported. Kaplan-Meier survival analysis was performed. Subgroups (RHA type, early vs. delayed surgery, RHA removed vs. retained) were compared., Results: At a median clinical follow-up of 9.5 years (range: 6.0-28.4 years), median MEPS was 80.0 (interquartile range [IQR]: 60.0-97.5), median QuickDASH was 22.0 (IQR: 4.6-42.6), median visual analog scale was 1 (IQR: 0-4), median postoperative satisfaction was 2 (IQR: 1-3), and median arc of extension/flexion was 110° (IQR: 80°-130°). Radiographic follow-up was available for 48 patients at a median of 7.0 years (range: 2.0-15.0 years). Heterotopic ossifications were seen in 14 (29.2%), moderate-to-severe capitellar osteopenia/abrasion in 3 (6.1%), moderate-to-severe ulnohumeral degeneration in 3 (6.1%), and periprosthetic radiolucencies in 17 (35.4%) patients. Twenty-nine patients (37.2%) had complications and 20 patients (25.6%) underwent RHA exchange or removal. Kaplan-Meier analysis with failure defined as RHA exchange or removal demonstrated survival of 75.1% (95% confidence interval: 63.7-83.3) at 18 years. The highest annual failure rate was observed in the first year in which the RHAs of 7 patients (9%) were exchanged or removed. No significant differences were detected between type of RHA in MEPS (Mathys: 82.5 [75.0-100] vs. Evolve: 80.0 [60.0-95.0]; P = .341) and QuickDASH (Mathys: 12.5 [0-34.4] vs. Evolve: 26.7 [6.9-46.2]; P = .112). Early surgery (≤3 weeks) yielded significantly superior MEPS (80.0 [70.0-100.0] vs. 52.5 [30.0-83.8]; P = .014) and QuickDASH (18.6 [1.5-32.6] vs. 46.2 [31.5-75.6]; P = .002) compared with delayed surgery (>3 weeks). Patients with retained RHAs had significantly better MEPS (80.0 [67.5-100] vs. 70.0 [32.5-82.5]; P = .016) and QuickDASH (18.1 [1.7-31.9] vs. 49.1 [22.1-73.8]; P = .007) compared with patients with removed RHAs., Conclusions: Long-term outcomes for RHA are satisfactory; however, there is a high complication and revision rate, resulting in implant survival of 75.1% at 18 years with the highest annual failure rate observed in the first postoperative year., (Copyright © 2021 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Revision rates following radial head arthroplasty (RHA) for unreconstructible radial head fractures (RHFs) differ vastly in the literature, and little is known about the risk factors that are associated with revision surgery. The purposes of this study were to assess the revision rate following RHA and to determine the associated risk factors., Methods: A total of 122 patients (mean age, 50.7 years; range, 18 to 79 years) with 123 RHAs who underwent RHA for unreconstructible RHFs between 1994 and 2014 and were ≥3 years out from surgery were included. Demographic variables, injury and procedure-related characteristics, radiographic findings, complications, and revision procedures were assessed. Cox regression analysis was performed to identify the risk factors that were associated with revision surgery following RHA., Results: The median follow-up for the study cohort was 7.3 years (interquartile range [IQR], 5.1 to 10.1 years). All of the patients had unreconstructible RHFs: Mason-Johnston type-IV injuries were the most prevalent (80 [65%]). One or more associated osseous or ligamentous injuries were seen in 89 elbows (72.4%). The median time to surgery was 7 days (IQR, 3 to 11 days). Implanted prostheses were categorized as rigidly fixed (65 [52.8%]) or loosely fixed (58 [47.2%]). A total of 28 elbows (22.8%) underwent revision surgery at a median of 1.1 years (IQR, 0.3 to 3.8 years), with the majority of elbows (17 [60.7%]) undergoing revision surgery within the first 2 years. The most common reason for revision surgery was painful implant loosening (14 [29.2% of 48 complications]). Univariate Cox regression suggested that Workers' Compensation claims (hazard ratio [HR], 5.48; p < 0.001) and the use of an external fixator (HR, 4.67; p = 0.007) were significantly associated with revision surgery., Conclusions: Revision rates following RHA for unreconstructible RHFs are high; the most common cause for revision surgery is painful implant loosening. Revision surgeries are predominantly performed within the first 2 years after implantation, and surgeons should be aware that Workers' Compensation claims and the use of an external fixator in management of the elbow injury are associated with revision surgery., Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence., Competing Interests: Disclosure: The authors indicated that no external funding was received for any aspect of this work. The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article (http://links.lww.com/JBJS/G347)., (Copyright © 2021 by The Journal of Bone and Joint Surgery, Incorporated.)

The purpose of this study was to compare adverse events and clinical outcomes of geriatric proximal humerus fractures (PHF) involving the anatomical neck (type C according to AO classification) treated with open reduction and internal fixation (ORIF) using locking plate vs. arthroplasty. In this retrospective cohort study, geriatric patients (>64 years) who underwent operative treatment using ORIF or arthroplasty for type C PHFs were included. Complications, revisions and clinical outcomes using Constant Murley Score (CMS) and Disabilities of the Arm, Shoulder and Hand (DASH) Score were assessed and compared between groups. At a mean follow up of 2.7 ± 1.7 years, 59 patients (mean age 75.3 ± 5.5 years) were included. In 31 patients ORIF was performed and 29 patients underwent arthroplasty. Complications and revision surgeries were significantly more frequent after ORIF (32.6% vs. 7.1%, p = 0.023 and 29.0% vs. 7.1%, p = 0.045). In contrast, clinical outcomes showed no significant differences (DASH 39.9 ± 25.7 vs. 39.25 ± 24.5, p = 0.922; CMS 49.7 ± 29.2 vs. 49.4 ± 25.2, p = 0.731). ORIF of type C PHFs in geriatric patients results in significantly more complications and revision surgery when compared to arthroplasty. Therefore, osteosynthesis of geriatric intraarticular fractures of the proximal humerus must be critically evaluated.

Tendon mobility is highly relevant in rotator cuff surgery. Objective data about rotator cuff mobility is rare. Tendon mobility still needs to be evaluated subjectively by the surgeon. This study aims to establish a porcine animal model for mobility analysis of the supraspinatus. In this context, we introduce a sensor-enhanced, arthroscopic grasper (SEAG) suitable for objective intraoperative measurements of tendon mobility in clinical praxis. Tendon mobility of 15 fresh porcine cadaver shoulders with artificial rotator cuff tears was evaluated using the SEAG. Mobility characteristics (load-displacement curves, maximum load, stiffness) were studied and inter- and intraobserver agreement (intraclass correlation coefficient (ICC)) were tested. Factors with a potential adverse effect (plastic deformation and rigor mortis) were also evaluated. All shoulders showed characteristic reproducible load-displacement curves with a nonlinear part at the start, followed by a linear part. Mean maximum load was 28.6 N ± 12.5. Mean stiffness was 6.0 N/mm ± 2.6. We found substantial interobserver agreement (ICC 0.672) and nearly perfect intraobserver agreement (0.944) for maximum load measurement. Inter- (0.021) and intraobserver (0.774) agreement for stiffness was lower. Plastic deformation and rigor mortis were excluded. The animal model demonstrates reliable and in vivo-like measurements of tendon mobility. The SEAG is a reliable tool for tendon mobility assessment.

Introduction: Rotator cuff tears (rct) subsequent to glenohumeral dislocation are relevant concomitant injuries, can lead to impaired shoulder function and increase risk of recurrent dislocation., Aim: The aim of this study was to determine the functional outcome, recurrent dislocation rate and tendon integrity after rotator cuff repair after primary traumatic shoulder dislocation., Materials and Methods: In this retrospective case series, 23 patients (age 56.4 years ± 6.3) who underwent a rotator cuff reconstruction after primary traumatic shoulder dislocation with confirmed combination of full-thickness RCT and Bankart lesion were enrolled after a minimum follow-up of 2 years. Clinical outcome (age and gender adjusted Constant Murley Score (CMS), DASH, Rowe Score) (n = 23) and sonographic tendon integrity (n = 19) were studied., Results: After a mean follow-up of 58 ± 32 months, a CMS of 85.1% ± 14.7, DASH of 14.2 ± 20.5, and Rowe Score of 82.4 ± 15.2 indicated good functional outcome. In 4 of 19 patients (21.1%) a re-tear was found during sonographic evaluation. In 3 cases (13%), a revision was performed (2 × stiff shoulder, 1 × postoperative infection). One patient had a single traumatic re-dislocation (4.3%)., Conclusions: Patients undergone reconstruction of the rotator cuff following a primary traumatic shoulder dislocation can achieve good functional results and a low rate of recurrent dislocation. Postoperative tendon integrity is comparable with known data about non traumatic tears.

Background: The treatment of fracture-related infections (FRI) is still a challenge for orthopedic surgeons. The prevalence of FRI is particularly high in open fractures with extensive soft-tissue damage. This study aimed to develop a new two-step animal model for non-unions with segmental bone defects, which could be used to evaluate new innovative bone substitutes to improve the therapeutic options in humans with FRI and bone defects., Methods: After randomization to infected or non-infected groups, 30 Sprague-Dawley rats underwent a transverse osteotomy of the mid-shaft femur with a 5 mm defect. Additionally, the periosteum at the fracture zone was cauterized at both sides. After intramedullary inoculation with 10 3  CFU Staphylococcus aureus (infected group) or PBS (non-infected group), a fracture stabilization was done by intramedullary K-wires. After 5 weeks, the bone healing process was evaluated, and revision surgery was performed in order to obtain increased bone healing. The initial K-wires were removed, and debridement of the osteotomy-gap was done followed by a more stable re-osteosynthesis with an angle-stable plate. After further 8 weeks all rats were euthanized and the bone consolidation was tested biomechanically and the callus formation quantitatively by micro-CT analysis., Results: We developed and presented a new two-stage non-union animal model through a targeted S. aureus infection. After 5 weeks, all animals showed a non-union irrespective of assignment to the infected and non-infected group. Lane and Sandhu score showed a higher callus formation in the infected group. In all infected animals, the inoculated S. aureus strain was detected in the revision surgery. The second surgery did not improve bone healing, as shown by the Lane Sandhu score and in the μ-CT analysis. Similarly, biomechanical testing showed in both groups a significantly lower maximum torque as compared to the contralateral side (p < 0.0001)., Conclusions: We were able to successfully develop a new two-stage non-union animal model, which reflects a genuine clinical situation of an infection-related non-union model with segmental bone defects. This model could be used to evaluate various therapeutic anti-infectious and osteoinductive strategies in FRIs.

Background: Bone-graft substitutes are commonly used for the augmentation of traumatic bone defects in tibial plateau fractures. However, their clinical performance compared with that of autologous bone-grafting, the gold standard in bone defect reconstruction, still remains under debate. This study investigates the differences in quality of life, pain, and radiographic outcomes in the treatment of tibial plateau fracture-associated bone defects with either autologous bone grafts or a bioresorbable hydroxyapatite and calcium sulfate cement (CERAMENT BONE VOID FILLER [CBVF]; BONESUPPORT)., Methods: In this study, 135 patients with acute depression and split-depression fractures of the proximal part of the tibia (OTA/AO types 41-B2 and 41-B3) were enrolled in a prospective, controlled, randomized, multicenter trial including 20 hospitals in Germany. Patients were randomized to receive either autologous iliac bone graft or CBVF for reconstruction of the bone defect. The primary outcome measures were the Short Form (SF)-12 version 2 Physical Component Summary (PCS) score at week 26 (the study was designed to show noninferiority of the CBVF with regard to the PCS with a prespecified margin of -5 points) and the pain level at 26 weeks postoperatively measured by a visual analog scale (VAS). The secondary outcomes were the SF-12 version 2 Mental Component Summary (MCS) and SF-12 PCS scores at weeks 1, 6, and 12 and bone-healing on radiographs., Results: Age, sex, fixation methods, and fracture pattern were comparable in both groups. There were no significant differences (p > 0.05) in the SF-12 PCS or VAS scores at postoperative week 26. There was a significant reduction of blood loss (p = 0.007) and pain levels (p = 0.008) at postoperative day 1 in the CBVF group. The rates of fracture-healing, defect remodeling, and articular subsidence were not significantly different (p > 0.05) in both groups., Conclusions: Bioresorbable CBVF was noninferior to autologous bone graft with regard to both patient-reported and radiographic outcomes in tibial plateau fractures of OTA/AO types 41-B2 and 41-B3., Level of Evidence: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Background: The aim of the study was to analyze the functional and radiological outcome of Monteggia-like lesions in adults with unreconstructible fracture of the radial head and treatment with radial head arthroplasty., Methods: Twenty-seven patients (mean age 56 years; range 36 to 79 years) with a Monteggia-like lesion and treatment with radial head replacement were included in this retrospective study. Minimum follow-up was 2 years. Clinical assessment included the pain level with the visual analog scale in rest (VAS R ) and under pressure (VAS P ), range of motion, Mayo Elbow Performance Score (MEPS), and Disability of the Arm, Shoulder, and Hand score (DASH). A detailed radiological evaluation was performed. Complications and revisions were also analyzed., Results: After a mean follow-up period of 69 months (range, 24 to 170) the mean DASH score was 30 ± 24, the MEPS averaged 77 ± 20 points, the mean VAS R was 2.1 ± 2.4, and VAS P was 4.5 ± 3.5. Mean loss of extension was 24° ± 18 and flexion was 124° ± 20. Heterotopic ossifications were noted in 12 patients (44%). A total of 17 complications were noted in 11 patients (41%), leading to 15 revision surgeries in 9 patients (33%). Patients with a complicated postoperative course showed a worse clinical outcome compared with patients without complications measured by MEPS (68 ± 22 vs. 84 ± 16), DASH (49 ± 16 vs. 20 ± 22) and ulnohumeral motion (77° ± 31 vs. 117° ± 23)., Conclusions: Monteggia-like lesions with unreconstructible radial head fracture and treatment with radial head replacement are prone to complications and revisions.

Purpose: To compare and evaluate knee laxity and functional outcomes between autologous bone graft and silicate-substituted calcium phosphate (Si-CaP) in the treatment of tunnel defects in 2-stage revision anterior cruciate ligament reconstruction (ACLR)., Methods: This prospective, randomized controlled trial was conducted between 2012 and 2015 with a total of 40 patients who underwent 2-stage revision ACLR. The tunnels were filled with autologous iliac crest cancellous bone graft in 20 patients (control group) and with Si-CaP in the other 20 patients (intervention group). After a minimum follow-up period of 2 years, functional outcomes were assessed by KT-1000 arthrometry (side-to-side [STS] difference), the Tegner score, the Lysholm score, and the International Knee Documentation Committee score., Results: A total of 37 patients (follow-up rate, 92.5%) with an average age of 31 years were followed up for 3.4 years (range, 2.2-5.5 years). The KT-1000 measurement did not show any STS difference between the bone graft group (0.9 ± 1.5 mm) and the Si-CaP group (0.7 ± 2.0 mm) (P = .731). One patient in the intervention group (5%) had an STS difference greater than 5 mm. Both groups showed significant improvements in the Tegner score, Lysholm score, and International Knee Documentation Committee score from preoperative assessment to final follow-up (P ≤ .002), without any difference between the 2 groups (P ≥ .396). Complications requiring revision occurred in 4 control patients (22%) and in 2 patients in the intervention group (11%) (P = .660). No complications in relation to Si-CaP were observed., Conclusions: Equivalent knee laxity and clinical function outcomes were noted 3 years after surgery in both groups of patients. Si-CaP bone substitute is therefore a safe alternative to autologous bone graft for 2-stage ACLR., Level of Evidence: Level I, prospective, randomized controlled clinical trial., (Copyright © 2019 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: The aim of this study was to analyze sports participation after radial head arthroplasty among recreational athletes., Methods: A total of 57 recreational athletes (mean age, 49 years; age range, 18-79 years) treated with radial head arthroplasty for non-reconstructible radial head fractures were included in this retrospective study. The return-to-sports rate and the time to return to sports were analyzed. The clinical and radiologic outcomes were compared between patients who returned to sports (group 1) and those who did not (group 2)., Results: After a mean follow-up period of 8.4 years (range, 2.5-16.4 years), 30 of 57 patients (53%) had returned to sports. The mean sports frequency significantly decreased from 5.2 ± 5.0 h/week to 2.2 ± 2.9 h/week after surgery (P < .001). In group 1, 83% of patients returned to the same sports activity whereas 17% changed to a less demanding sports activity. The mean time to return to sports was 158 days (range, 21-588 days). Patients who returned to sports had a significantly better Mayo Elbow Performance Score (MEPS) (84 ± 19 points vs. 63 ± 20 points, P < .001); Disabilities of the Arm, Shoulder and Hand score (16 ± 17 vs. 46 ± 22, P < .001); and arc of flexion (114° ± 32° vs. 89° ± 36°, P = .007). A secondary radial head prosthesis (P = .046) and MEPS lower than 85 points (P = .001) were associated with a significantly lower return-to-sports rate. No differences regarding radiographic changes were found between the 2 groups (P ≥ .256)., Conclusion: The return-to-sports rate after radial head replacement is low. A secondary radial head prosthesis and a worse clinical outcome (MEPS < 85 points) significantly increase the risk of not returning to sports after radial head arthroplasty., (Copyright © 2019 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)