The arthroscopic treatment of anterior shoulder instability with glenoid bone loss shows similar clinical results after Latarjet procedure and iliac crest autograft transfer.

PURPOSE: Recurrent anterior shoulder instability caused by critical bone loss of the glenoid is a challenging condition for shoulder surgeons. The purpose of this prospective multicenter trial was to compare the arthroscopic transfer of the coracoid process (Latarjet procedure) with the arthroscopic reconstruction of the glenoid using iliac crest autografts. METHODS: A prospective multi-center trial was performed in nine orthopaedic centres in Austria, Germany and Switzerland between July 2015 and August 2021. Patients were prospectively enrolled and received either an arthroscopic Latarjet procedure or an arthroscopic iliac crest graft transfer. Standardized follow-up after 6 months and mimimum 24 months included range of motion, Western Ontario stability index (WOSI), Rowe score and subjective shoulder value (SSV). All complications were recorded. RESULTS: 177 patients (group Latarjet procedure: n = 110, group iliac crest graft: n = 67) were included in the study. WOSI (n.s.), SSV (n.s.) and Rowe score (n.s.) showed no difference at final follow-up. 10 complications were seen in group Latarjet procedure and 5 in group iliac crest graft; the frequency of complications did not differ between the two groups (n.s.). CONCLUSION: The arthrosopic Latarjet procedure and arthroscopic iliac crest graft transfer lead to comparable results regarding clinical scores, frequency of recurrent dislocations and complication rates. LEVEL OF EVIDENCE: Level II.

Assessment of return to play after an acute shoulder injury: protocol for an explorative prospective observational German multicentre study.

INTRODUCTION: To date, there is no valid single test or battery of tests for informing return-to-play (RTP) decisions following an acute shoulder injury. The purpose of this exploratory study is to evaluate a diagnostic test battery based on a Delphi consensus at the time of unrestricted return to team training after acute shoulder injury. METHODS AND ANALYSIS: Data for this prospective multicentre cohort study are collected at two measurement time points: when the respective physician clears the patient for RTP (t1) and 12 months after RTP (t2). The study participants are 18-35 years old athletes participating at a professional level in the following team sports: handball, basketball, ice hockey, soccer, volleyball and American football. Maximum comparability will be ensured via uninjured matched pair teammates. To assess the subjective assessment of shoulder functioning and the athlete's readiness to RTP, patient-reported outcome measures (Western Ontario Shoulder Instability Index, Quick-Disabilities of the Arm, Shoulder and Hand, Psychological Readiness of Injured Athlete to Return to Sport and Shoulder Instability-Return to Sport after Injury) will be completed. After a medical check-up with a range of motion and anthropometric measurements as well as clinical tests, the participants will perform a structured warm-up protocol. The functional tests comprise handgrip strength, upper quarter Y-balance test, isometric strength, closed kinetic chain upper extremity stability test, wall hop test, functional throwing performance index and the unilateral seated shot put test and isokinetic tests. ETHICS AND DISSEMINATION: The results of this study will be disseminated through peer-reviewed publications and scientific presentations at national and international conferences. Ethical approval was obtained through the Institutional Review Board of Martin-Luther-University Halle-Wittenberg (reference number: 2022-016). TRIAL REGISTRATION NUMBER: DRKS00028265.

Lag screw osteosynthesis of simple olecranon fractures: A biomechanical comparative study.

Olecranon fractures are most frequently stabilized by tension band wiring (TBW), which unfortunately leads to relevant implant removal rates due to K-wire migration and soft tissue irritation. As lag screw osteosynthesis (LSO) might be a gentle and effective alternative in simple fracture patterns, the goal of the present study was to biomechanically compare LSO with TBW in simple olecranon fractures at a cadaver model. A simple olecranon fracture (Mayo type IIA) was created in eight pairs of human cadaver elbows, which were pairwise fixed by either TBW or two transcortical 4.0 mm lag screws. Biomechanical testing was conducted as a pulling force, applied to the triceps tendon in a 90° position. First, cyclic loading between 10 and 300 N was performed for 50,000 cycles. Afterward, maximum load was raised by 0.02 N/cycle until construct failure, what was defined as displacement >2 mm. Besides fracture displacement, failure cycle and failure load, the modes of failure were analyzed. Within the first five cycles, there was no significant difference in displacement (median TBW: 0.2 mm; LSO: 0.5 mm; p = 0.091). Both after 2000 (median TBW: 0.2 mm; LSO: 0.6 mm; p = 0.042) and after 20,000 cycles (median TBW: 0.4 mm; LSO: 0.9 mm; p = 0.027), the difference was significant. Failure cycle (median TBW: 72,639 cycles; LSO: 43,429 cycles; p = 0.017) and failure load (median TBW: 702 N; LSO: 303 N; p = 0.025) differed significantly as well. TBW mostly (6/8) failed at the lock of the cerclage wire, whereas most LSO constructs (5/8) failed as a pullout of the proximal fragment. In conclusion, to our biomechanical findings at human cadaver specimens, simple olecranon fractures treated by LSO show higher dislocation rates and lower failure loads compared to conventional TBW and mostly fail by pullout of the proximal fragment.

Autologous Minced Cartilage Implantation for Arthroscopic One-Stage Treatment of Osteochondritis Dissecans of the Elbow.

This Technical Note describes the full arthroscopic one-stage treatment of high-grade osteochondritis dissecans of the humeral capitellum of the elbow joint by means of minced cartilage implantation.

Preliminary sampling of aflatoxin M1 contamination in raw milk from dairy farms using feed ingredients from Rwanda.

Milk is susceptible to aflatoxin M1 (AFM1) contamination when dairy cattle consume feed contaminated with aflatoxins and is considered as a public health concern. This pilot study assessed the prevalence and amount of total aflatoxin contamination in commercially available dairy feed and the corresponding AFM1 contamination in raw milk from samples collected at farms using local, commercially available dairy feed across Rwanda's five provinces. The inclusion criteria to select dairy farm participants were (1) to have at least two cows and (2) use of commercially prepared dairy feeds. Importantly, the majority of cattle rearing households in Rwanda rely principally on grazing or other freely available feedstock, rather than on commercially prepared feeds. In total, 170 raw milk samples were collected during one sampling period from dairy farms using commercially prepared dairy feeds. In addition, 154 dairy feed samples were collected simultaneously with the milk samples. These farms were previously targeted in a larger study measuring aflatoxin contamination of Rwandan feeds and feed ingredients. The mean AFM1 concentration in these samples was 0.89 ± 1.64 µg/l (median: 0.33 µg/l) with a maximum of 14.5 µg/l. Maize bran was the principal dairy feed ingredient used by farmers in the sampling, representing more than 65% of the total feed samples collected, with mean aflatoxin concentration of 90.5 µg/kg (median 32.3 µg/kg). The authors note that this preliminary sampling is not generalizable across Rwandan milk production and consumption; the limited pilot study presented here was not designed with the robustness necessary for broad-scale generalization. Thus, the data presented should not be broadly applied outside of the context of the study.

Conservative treatment of acute traumatic posterior shoulder dislocations (Type A) is a viable option especially in patients with centred joint, low gamma angle, and middle or old age.

PURPOSE: Purpose of this study was to evaluate the mid- to long-term outcome after conservatively treated first-time posterior shoulder dislocations and to determine structural defects associated with failure. METHODS: In this multi-centric retrospective study, 29 shoulders in 28 patients with first-time acute posterior shoulder dislocation (Type A1 or A2 according to the ABC classification) and available cross-sectional imaging were included. Outcome scores as well as radiological and magnetic resonance imaging were obtained at a mean follow-up of 8.3 ± 2.7 years (minimum: 5 years). The association of structural defects with redislocation, need for secondary surgery, and inferior clinical outcomes were analysed. RESULTS: Redislocation occurred in six (21%) shoulders and nine shoulders (31%) underwent secondary surgery due to persistent symptoms. The posttraumatic posterior glenohumeral subluxation was higher in the redislocation group compared to the no redislocation group; however, statistical significance was not reached (61.9 ± 12.5% vs. 50.6 ± 6.4%). Furthermore, a higher adapted gamma angle was observed in the failed conservative treatment group versus the conservative treatment group, similarly without statistically significant difference (97.8° ± 7.2°, vs. 93.3° ± 9.7°). The adapted gamma angle was higher than 90° in all patients of failed conservative therapy and the redislocation group. An older age at the time of dislocation showed a significant correlation with better clinical outcomes (SSV: r = 0.543, p = 0.02; ROWE: r = 0.418, p = 0.035 and WOSI: r = 0.478, p = 0.045). Posterior glenohumeral subluxation after trauma correlated with a worse WOSI (r = - 0.59, p = 0.02) and follow-up posterior glenohumeral decentring (r = 0.68, p = 0.007). The gamma angle (r = 0.396, p = 0.039) and depth of the reverse Hill-Sachs lesion (r = 0.437, p = 0.023) correlated significantly with the grade of osteoarthritis at follow-up. CONCLUSION: Conservative treatment is a viable option in patients with an acute traumatic posterior shoulder dislocation with good outcome after mid- and long-term follow-up especially in patients with centred joint, low gamma angle, and middle or old age. LEVEL OF EVIDENCE: IV.

Simple traumatic elbow dislocations; benefit from early functional rehabilitation: A systematic review with meta-analysis including PRISMA criteria.

INTRODUCTION: Elbow dislocation is the second most frequent joint dislocation after shoulder dislocation. They have a high relevance because they can result in subsequent damage and limitations in range of motion. The treatment options are controversially discussed.The purpose of this systematic review and meta-analysis was to review the literature and analyze the evidence of early functional rehabilitation. METHODS: A systematic literature search was performed via Ovid Medline, whereby 1645 publications were identified and evaluated in a stepwise approach. Of these publications 29 met the inclusion criteria of the authors and described simple elbow dislocations in 5765 patients.Data from the studies and subgroups included were initially categorized descriptively in conservative and surgical primary therapies, in immobilizing (immobilization lasting 2 weeks or longer) and free-functional follow-up treatments, and those data were then extracted from each subgroup in absolutes. We then pooled these numbers into descriptive statistics to ensure their comparability. We determined the success rates from the numbers of excellent and good results of the specific used outcome scores. RESULTS: The effect estimate of the conservative therapy's success rate was 84% and for surgical treatment 80% (P < .0001). The difference between the immobilizing treatment (78% success rate) and early-function therapy (83% success rate) was significant (P = .002).In a subgroup analysis the success rate of conservative and immobilizing therapy was 79%, of conservative and early-functional therapy 91%, of surgical and immobilizing groups' was 77% and of the surgical and early-functional therapies was 93%. The difference among the 4 treatment options was significant (P < .0001), as were differences between the 2 conservative groups (P < .0001) and between the 2 surgical groups (P = .044). DISCUSSION: Conservative therapy is the dominant therapy. Regardless of the primary therapy chosen in simple elbow dislocations: early functional follow-up care seems to be superior to immobilizing therapy with a duration more than 2 weeks.

Influence of surgical stabilization of clavicle fractures in multiply-injured patients with thoracic trauma.

Thoracic trauma has decisive influence on the outcome of multiply-injured patients and is often associated with clavicle fractures. The affected patients are prone to lung dysfunction and multiple organ failure. A multi-center, retrospective analysis of patient records documented in the TraumaRegister DGU was performed to assess the influence of surgical stabilization of clavicle fractures in patients with thoracic trauma. A total of 3,209 patients were included in the analysis. In 1362 patients (42%) the clavicle fracture was treated operatively after 7.1 ± 5.3 days. Surgically treated patients had a significant reduction in lung failure (p = 0.013, OR = 0.74), multiple organ failure (p = 0.001, OR = 0.64), intubation time (p = 0.004; -1.81 days) and length of hospital stay (p = 0.014; -1.51 days) compared to non-operative treatment. Moreover, surgical fixation of the clavicle within five days following hospital admission significantly reduced the rates of lung failure (p = 0.01, OR = 0.62), multiple organ failure (p = 0.01, OR = 0.59) and length of hospital stay (p = 0.01; -2.1 days). Based on our results, multiply-injured patients with thoracic trauma and concomitant clavicle fracture may benefit significantly from surgical stabilization of a clavicle fracture, especially when surgery is performed within the first five days after hospital admission.

Toxigenic mycoflora, aflatoxin and fumonisin contamination of poultry feeds in Ghana.

The study was undertaken to identify the major mycotoxigenic fungi, aflatoxin and fumonisin levels in prepared poultry feeds in Ghana. Three hundred and fifty (350) prepared feed samples were randomly collected from 133 commercial poultry farms, 76 feed processors and eight (8) feed vendors in three major poultry producing regions of Ghana over two seasons. Fungi were isolated using the serial dilution method on potato dextrose agar and identified using standard methods of identification. Total aflatoxin and fumonisin levels were quantified using AgraStrip® Total Aflatoxin and Fumonisin Quantitative test Watex® from RomerLab, USA. Eight (8) different fungi were isolated from the feed samples with isolation frequency as follows: Aspergillus flavus (47%), A. niger (24%), A. fumigatus (17%), A. oryzae (3%), A. tamarii (2%), Penicillium sp. (3%), Colletotrichum sp. (4%) and Rhizopus sp. (0.1%). Feed samples collected during the rainy season recorded higher mean colony counts (3.39 ± 0.29) than that of the dry season (1.10 ± 0.18). Total aflatoxin and fumonisin levels ranged from 0 to 118 ppb with a mean of 57.25 ± 2.55 ppb, and 0.28-15 ppm with a mean of 1.54 ± 0.12 ppm, respectively. The study revealed co-occurrence of aflatoxin and fumonisin in all the feed samples. Significant correlations (r = 0.298, r = 0.694) (p < 0.05) were observed among the aflatoxin and fumonisin levels and the fungi isolated. Seventy-four percent (74%) of all the feed samples exceeded the 15 ppb Ghana Standards Authority threshold, the EU regulatory limit of 20 ppb and the FAO/WHO recommended maximum permissible limit of 30 ppb for poultry feeds. Although fumonisin levels were less than the EU guidance values of 20 ppm for poultry feeds, 20% of the samples were higher than the FAO/WHO maximum tolerable daily intake limit of 2 ppm. Proper handling of prepared feeds and ingredients could prevent or minimize toxigenic fungi contamination and lower the likelihood of mycotoxin development in poultry feeds.

Cytotoxicity assessment of Aflatoxin B1 after high voltage atmospheric cold plasma treatment.

Aflatoxin B1 (AFB1) is a secondary metabolite produced by Aspergillus flavus and A. parasiticus, and is a known carcinogen in humans and animals. High voltage atmospheric cold plasma (HVACP) technology has already shown promise to decontaminate AFB1 in food and feed. This study aimed to investigate the cytotoxicity of AFB1 after HVACP treatment. AFB1 (100 µM) was treated at 85 kV with HVACP for 0, 2, 5, 10, and 20 min. HepG2 cells were exposed to HVACP-treated AFB1 for 72 h and assessed for cell viability, caspase-3 activity, DNA fragmentation, and protein carbonyls for each treatment time. Cell viability, caspase-3 activity, DNA fragmentation levels, and protein carbonyls contents of HepG2 cells exposed to HVACP-treated AFB1 after 20 min was not significantly different compared to non-exposed HepG2 cells (P > 0.05). However, their contents were significantly higher in non-exposed cells compared to the other HVACP treatment times (P < 0.01). Twenty minutes of HVACP treatment for AFB1 significantly reduced AFB1 cytotoxicity and oxidative damage and showed potential as a safe aflatoxin decontamination technology.

Immobilization in External Rotation and Abduction Versus Arthroscopic Stabilization After First-Time Anterior Shoulder Dislocation: A Multicenter Randomized Controlled Trial.

BACKGROUND: Treatment of first-time shoulder dislocation (FSD) is a topic of debate. After high rates of recurrent instability after nonoperative management were reported in the literature, primary repair of FSD significantly increased. At the same time, new concepts were proposed that had promising results for immobilization in external rotation (ER) and abduction (ABD). PURPOSE: The aim of this study was to evaluate the recurrence rates (primary outcome) and clinical outcomes (secondary outcome parameters) of immobilization in ER+ABD versus arthroscopic primary stabilization after FSD. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: In a multicenter randomized controlled trial, patients with FSD were randomized to either treatment with immobilization in 60° of ER plus 30° of ABD (group 1) or surgical treatment with arthroscopic Bankart repair (group 2). Clinical evaluation was performed 1, 3, and 6 weeks as well as 6, 12, and 24 months postoperatively or after reduction, including range of motion, instability testing, subjective shoulder value, Constant-Murley score, Rowe score, and Western Ontario Shoulder Instability Index. Recurrent instability events were prospectively recorded. RESULTS: Between 2011 and 2017, a total of 112 patients were included in this study. Of these, 60 patients were allocated to group 1 and 52 to group 2. At the 24-month follow-up, 91 patients (81.3%) were available for clinical examination. The recurrence rate was 19.1% in group 1 and 2.3% in group 2 (P = .016). No significant differences were found between groups regarding clinical shoulder scores (P > .05). Due to noncompliance with the immobilization treatment protocol, 4 patients (6.7%) were excluded. CONCLUSION: Immobilization in ER+ABD versus primary arthroscopic shoulder stabilization for the treatment of FSD showed no differences in clinical shoulder scores. However, recurrent instability was significantly higher after nonoperative treatment.

Low-profile double plating of unstable osteoporotic olecranon fractures: a biomechanical comparative study.

BACKGROUND: In the treatment of unstable olecranon fractures, anatomically preshaped locking plates exhibit superior biomechanical results compared with tension band wiring. However, posterior plating (PP) still is accompanied by high rates of plate removal because of soft-tissue irritation and discomfort. Meanwhile, low-profile plates precontoured for collateral double plating (DP) are available and enable muscular soft-tissue coverage combined with angular-stable fixation. The goal of this study was to biomechanically compare PP with collateral DP for osteosynthesis of unstable osteoporotic fractures. METHODS: A comminuted displaced Mayo type IIB fracture was created in 8 osteoporotic pairs of fresh-frozen human cadaveric elbows. Pair-wise angular stable fixation was performed by either collateral DP or PP. Biomechanical testing was conducted as a pulling force to the triceps tendon in 90° of elbow flexion. Cyclical load changes between 10 and 300 N were applied at 4 Hz for 50,000 cycles. Afterward, the maximum load was raised by 0.02 N/cycle until construct failure, which was defined as displacement > 2 mm. Besides failure cycles and failure loads, modes of failure were analyzed. RESULTS: Following DP, a median endurance of 65,370 cycles (range, 2-83,121 cycles) was recorded, which showed no significant difference compared with PP, with 69,311 cycles (range, 150-81,938 cycles) (P = .263). Failure load showed comparable results as well, with 601 N (range, 300-949 N) after DP and 663 N (range, 300-933 N) after PP (P = .237). All PP constructs and 3 of 8 DP constructs failed by proximal fragment cutout, whereas 5 of 8 DP constructs failed by bony triceps avulsion. CONCLUSION: Angular-stable DP showed comparable biomechanical stability to PP in unstable osteoporotic olecranon fractures under high-cycle loading conditions. Failure due to bony triceps avulsion following DP requires further clinical and biomechanical investigation, for example, on suture augmentation or different screw configurations.

Injury patterns following simple elbow dislocation: radiological analysis implies existence of a pure valgus dislocation mechanism.

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.

Arthroscopic Bankart repair with an individualized capsular shift restores physiological capsular volume in patients with anterior shoulder instability.

PURPOSE: Capsular volume reduction in the context of anterior arthroscopic shoulder stabilization represents an important but uncontrolled parameter. The aim of this study was to analyse capsular volume reduction by arthroscopic Bankart repair with an individualized capsular shift in patients with and without ligamentous hyperlaxity compared to a control group. METHODS: In the context of a prospective controlled study, intraoperative capsular volume measurements were performed in 32 patients with anterior shoulder instability before and after arthroscopic Bankart repair with an individualized capsular shift. The results were compared to those of a control group of 50 patients without instability. Physiological shoulder joint volumes were calculated and correlated with biometric parameters (sex, age, height, weight and BMI). RESULTS: Patients with anterior shoulder instability showed a mean preinterventional capsular volume of 35.6 ± 10.6 mL, which was found to be significantly reduced to 19.3 ± 5.4 mL following arthroscopic Bankart repair with an individualized capsular shift (relative capsular volume reduction: 45.9 ± 21.9%; P < 0.01). Pre-interventional volumes were significantly greater in hyperlax than in non-hyperlax patients, while post-interventional volumes did not differ significantly. The average shoulder joint volume of the control group was 21.1 ± 7.0 mL, which was significantly correlated with sex, height and weight (P < 0.01). Postinterventional capsular volumes did not significantly differ from those of the controls (n.s.). CONCLUSION: Arthroscopic Bankart repair with an individualized capsular shift enabled the restoration of physiological capsular volume conditions in hyperlax and non-hyperlax patients with anterior shoulder instability. Current findings allow for individual adjustment and intraoperative control of capsular volume reduction to avoid over- or under correction of the shoulder joint volume. Future clinical studies should evaluate, whether individualized approaches to arthroscopic shoulder stabilization are associated with superior clinical outcome.

Biodegradable magnesium vs. polylactide pins for radial head fracture stabilization: a biomechanical study.

BACKGROUND: Biodegradable implants have gained increasing importance for the fixation of simple displaced radial head fractures to supersede implant removal and to minimize cartilage destruction. Commonly used polylactide pins still lead to higher rates of secondary loss of reduction compared with metal implants. Alternatively, implants made from a magnesium alloy meanwhile are available in a pin design that hypothetically could perform better than polylactide pins. Because biomechanical data of clinical applications are lacking, the goal of the present study was to biomechanically compare magnesium pins to polylactide pins using a Mason type II radial head fracture model. METHODS: Fourteen pairs of fresh-frozen human cadaver radii with a standardized Mason type II radial head fracture were stabilized either by two 2.0-mm polylactide pins (PPs) or two 2.0-mm magnesium pins (MPs). Biomechanical in vitro testing was conducted as 10 cycles of static loading at 0.1 Hz axially and transversally between 10 and 50 N. Afterward, loosening was tested by dynamic load changes at 4 Hz up to 100,000 cycles. Early fracture displacement was measured after 10,000 cycles. Afterward, maximum loads were raised every 10,000 cycles by 15 N until construct failure, which was defined as fracture displacement ≥2 mm. RESULTS: MP osteosynthesis showed a tendency toward higher primary stability on both axial (MP: 0.19 kN/mm, PP: 0.11 kN/mm; P = .068) and transversal loading (MP: 0.11 kN/mm, PP: 0.10 kN/mm; P = .068). Early fracture displacement was significantly higher following PP osteosynthesis (MP: 0.3 mm, PP: 0.7 mm; P = .030). The superiority of MP was also significant during cyclic loading, represented in a higher failure cycle (MP: 30,684, PP: 5113; P = .009) and in higher failure loads (MP: 95 N, PP: 50 N; P = .024). CONCLUSION: According to our findings, in simple radial head fractures, osteosynthesis with magnesium pins show superior biomechanical properties compared with fractures treated by polylactide pins. Prospective investigations should follow to evaluate clinical outcomes and resorption behavior.

The acromioclavicular ligament shows an early and dynamic healing response following acute traumatic rupture.

PURPOSE: Symptomatic horizontal instability is clinically relevant following acute acromioclavicular joint dislocations. However, the intrinsic healing response is poorly understood. The present study sought to investigate time-dependent healing responses of the human acromioclavicular ligament following acute traumatic rupture. METHODS: Biopsies of the acromioclavicular ligament were obtained from patients undergoing surgical treatment for acute acromioclavicular joint dislocations. Specimens were stratified by time between trauma and surgery: group 1, 0-7 days (n = 5); group 2, 8-14 days (n = 6); and group 3, 15-21 days (n = 4). Time-dependent changes in cellularity, collagen (type 1 and 3) concentration, and histomorphological appearance were evaluated for the rupture and intact zone of the acromioclavicular ligament. RESULTS: Group 1 was characterized by cellular activation and early inflammatory response. The rupture zone exhibited a significantly higher count of CD68-positive cells than the intact zone (15.2 vs 7.4; P ≤ 0.05). Consistently, synovialization of the rupture end was observed. Within the second week, the rupture zone was subject to proliferation showing more fibroblast-like cells than the intact zone (66.8 vs 43.8; P ≤ 0.05) and a peak of collagen type 3 expression (group 1: 2.2 ± 0.38, group 2: 3.2 ± 0.18, group 3: 2.8 ± 0.57; P ≤ 0.05). Signs of consolidation and early remodeling were seen in the third week. CONCLUSIONS: The acromioclavicular ligament exhibits early and dynamic healing responses following acute traumatic rupture. Our histological findings suggest that surgical treatment of acute ACJ dislocations should be performed as early as possible within a timeframe of 1 week after trauma to exploit the utmost biological healing potential. Prospective clinical studies are warranted to investigate whether early surgical treatment of ACJ dislocations translates into clinical benefits.

Biomechanical comparison of biodegradable magnesium screws and titanium screws for operative stabilization of displaced capitellar fractures.

BACKGROUND: Displaced fractures of the humeral capitellum are commonly treated operatively and fixed by titanium screws (TSs) either directly or indirectly. In the case of direct transcartilaginous fixation, biodegradable screws with the ability to be countersunk can be favorable regarding implant impingement and cartilage destruction. Hence, the goal of this study was to biomechanically compare headless compression screws made from titanium with a biodegradable equivalent made from a magnesium alloy. METHODS: This biomechanical in vitro study was conducted on 13 pairs of fresh-frozen human cadaveric humeri, in which a standardized Bryan-Morrey type I fracture was fixed using 2 magnesium screws (MSs) or 2 TSs. First, construct stiffness was measured during 10 cycles of static loading between 10 and 50 N. Second, continuous loading was applied at 4 Hz between 10 and 50 N, increasing the maximum load every 10,000 cycles by 25 N until construct failure occurred. This was defined by fragment displacement >3 mm. RESULTS: Comparison of the 2 screw types showed no differences related to construct stiffness (0.50 ± 0.25 kN/mm in MS group and 0.47 ± 0.13 kN/mm in TS group, P = .701), failure cycle (43,944 ± 21,625 and 41,202 ± 16,457, respectively; P = .701), and load to failure (152 ± 53 N and 150 ± 42 N, respectively; P = .915). CONCLUSION: Biomechanical comparison showed that simple capitellar fractures are equally stabilized by headless compression screws made from titanium or a biodegradable magnesium alloy. Therefore, in view of the advantages of biodegradable implants for transcartilaginous fracture stabilization, their clinical application should be considered and evaluated.

Fluoroscopic guided tunnel placement during medial patellofemoral ligament reconstruction is not accurate in patients with severe trochlear dysplasia.

PURPOSE: Accurate femoral tunnel placement is of great importance during medial patellofemoral ligament (MPFL) reconstruction. Purpose of the present study was to investigate the influence of trochlear dysplasia on the accuracy of fluoroscopic guided femoral tunnel placement. METHODS: CT-Scans of 30 knees (five with regular shaped trochlea, 10 with a Type A and five each with a Type B, C, or D trochlear dysplasia) were imported into the image analysis platform MeVisLab. A 3D Bone Volume Rendering (VR) and a virtual lateral radiograph was created. The anatomic femoral MPFL insertion was identified on the 3D VR. On virtual lateral radiographs, the MPFL insertion was identified based on landmarks described by Schöttle et al. using three different perspectives: Best possible overlap of the femoral condyles (BC) and a tangent along posterior border of the posterior femoral cortex (pBC); a tangent along the anterior border of the posterior cortex (aBC); and best possible overlap of the distal part of the posterior femoral cortex (BF). Distances between the anatomic attachment and radiographically obtained insertions were measured on the 3D VR and compared according to the type of trochlear dysplasia. RESULTS: Significantly lower accuracy of fluoroscopy guided tunnel placement in MPFL reconstruction was found in knees with Type C and D dysplasia. This effect was observed irrespectively from the radiologic perspective (pBC, aBC, and FC). In the pBC view (highest accuracy), the mean distance from the centre of the anatomic MPFL attachment to the radiographically defined location was 4.3 mm in knees without trochlear dysplasia and increased to 4.8 mm in knees with Type A dysplasia, 3.8 mm in knees with Type B dysplasia, 6.7 mm (p < 0.001) in knees with Type C dysplasia, and 7.3 mm (p < 0.001) in knees with Type D dysplasia. CONCLUSION: Radiographic landmark-based femoral tunnel placement in the pBC view provides highest accuracy in knees with a normal shaped trochlea or low grade trochlear dysplasia. In patients with severe dysplasia, fluoroscopy guided tunnel placement has a low accuracy, exceeding a critical threshold of 5 mm distance to the anatomic MPFL insertion irrespective of the radiographic perspective. In these patients, utilization of anatomic landmarks may be beneficial. LEVEL OF EVIDENCE: IV.

Anatomical Reconstruction of the Acromion Using an Autologous Iliac Crest Graft for Treatment of Recurrent Chondroblastoma: A Case Report.

CASE: A 38-year-old man presented with recurrent chondroblastoma of the acromion after primary curettage and bone grafting. The patient underwent revision surgery with resection of the acromion and reconstruction using an autologous iliac crest graft. He had regained normal shoulder function without recurrence at a follow-up of 17 months. CONCLUSIONS: This case demonstrates a rare location of chondroblastoma and successful anatomical and functional reconstruction. The described surgical procedure could be considered for large tumorous lesions of the acromion, for which curettage would be insufficient, and to preserve and reconstruct a functionally intact shoulder girdle.