Fracture-associated infection with Mycobacterium smegmatis in a 16-year old patient.

We present a patient who suffered an agricultural rollover trauma and developed a fracture-associated tissue infection caused by Mycobacterium smegmatis. Since cases are rare, treatment of infections with M. smegmatis requires an interprofessional approach and the combination of surgery and adjunctive antimicrobial treatment.

Conservative Versus Operative Treatment of Proximal Humerus Fractures in Older Individuals­an Analysis of Insurance Data.

BACKGROUND: Little is known about the frequency and results of conservative treatment of proximal humerus fractures in older individuals. METHODS: Billing data of the BARMER health insurance carrier for all patients of age 65 and above with proximal humerus fractures in the years 2005-2021 were retrospectively analyzed with multivariable Cox regression models, taking account of the patients' age, sex, and comorbidity profiles. The defined primary endpoints were overall survival (OS), major adverse events (MAE), thromboembolic events (TE), and complications of surgery or of trauma. Multivariable p values for the effect of treatment on all primary endpoints were jointly adjusted with the Bonferroni-Holm method. RESULTS: 54% of 81 909 patients were treated conservatively. Conservative treatment was more common in those who received their diagnosis as outpatients (79.5%, vs. 37.2% for inpatients). Operative treatment was associated with significantly longer overall survival (long-term HR 0.89, 95% confidence interval [0,86; 0,91]) and fewer MAE (0.90; [0.88; 0.92]) and TE (0.89; [0.87; 0.92]), but more complications due to surgery or trauma (1.66; [1,.4; 1.78]; all p < 0.001). 3.1% of the patients who had been initially treated conservatively underwent surgery within 6 months of their diagnosis. Risk factors for the failure of conservative treatment included alcohol abuse, obesity, cancer, diabetes mellitus, Parkinson disease, and osteoporosis. CONCLUSION: The conservative treatment of proximal humerus fracture is associated with a lower overall rate of complications due to surgery or trauma, but also with more MAE and TE and higher overall mortality. These findings underline the need for individualized and risk-adjusted treatment recommendations.

[Severe injury type procedures-Influence of the cipher 11 "complications" and the COVID-19 pandemic on a center for maximum care of severe injuries]. / Schwerstverletzungsartenverfahren ­ Einfluss der Ziffer 11 "Komplikationen" sowie der COVID-19-Pandemie auf ein Haus der traumatologischen Maximalversorgung.

INTRODUCTION: Ensuring the best treatment options for injured patients (healing process, Heilverfahren, HV) is the main goal and responsibility of the German statutory accident insurance (DGUV). The injury type catalogue is the tool to guide the HV. The development of the number of cases treated in a center for severe injury type procedures, the effects of the cipher 11 "complications" of the catalogue and the effects of the COVID-19 pandemic are presented. METHODS: A retrospective study of all patients treated in the context of the DGUV from January 2019 to December 2021 was carried out. The number of cases before and during the legal lockdown actions were compared. The case mix index, the mean number of operations, the mean time in the operating room and the hospital stay were analyzed. Additionally, the cases under the cipher 11 were classified according to the specific anatomical regions. RESULTS: Out of 2007 cases 67% were classified as severe injury type procedures (SAV). Of these cases 51% were categorized to the cipher 11 of the injury type catalogue. Complications were observed particularly in the anatomical regions of the shoulder girdle, elbow, hand, knee, ankle joint and foot. These complex cases are economically not sufficiently represented. During the governmental COVID-19 lockdown actions, the number of patients treated in the context of the DGUV significantly decreased. CONCLUSION: The injury type catalogue is used effectively in the catchment area of the present trauma center. Most of the cases treated in the present trauma center are severe injury type procedures; however, more than half of these cases are classified as complications. This development might show the need for a structural change or an adjustment of the HV. The current comments on the injury type catalogue offer important definitions and specifications; however, the conciseness of the entire catalogue should be maintained.

Acromioclavicular and coracoclavicular ligamentous insertion distances depend on the scapular tilt and decrease with anterior direction of the inferior scapula angle.

PURPOSE: A variety of reconstruction techniques exist for the operative treatment of a ruptured acromioclavicular and coracoclavicular ligamentous complex. However, the complication rate remains high; between 5 and 89%. The intraoperative distance between the clavicle, acromion and coracoid is important for the refixation quality. In this study, the influence of scapular deflection on coracoclavicular and acromioclavicular distances was analysed. METHODS: The ligamentous insertions of 24 fresh-frozen human scapulae were exposed. The coracoclavicular and acromioclavicular ligaments were referenced and captured in a rigid body system using a three-dimensional (3D) measurement arm. The inferior angle of the scapula was manually pulled into maximum anterior and posterior deflection, simulating a patient positioning with or without dorsal scapular support, respectively. Based on the rigid body system, the distances between the ligamentous insertions were calculated. Statistical evaluation was performed by setting the distances in anterior deflection to 100% and considering the other distances relative to this position. RESULTS: The scapular deflection had a considerable impact on the distance between the ligamentous insertions. Concerning the conoid ligament, the mean distance was almost doubled when the inferior angle pointed posteriorly compared to anterior deflection (195.3 vs 100.0%; p = 0.028). The insertion of the acromioclavicular capsule also showed a significant association with the direction of deflection (posterior = 116.1% vs. anterior = 100%; p = 0.008). CONCLUSION: Dorsal support shifting the inferior angle of the scapula anteriorly reduces the distance between the ligamentous insertions. Therefore, a patient position on a shoulder table with posterior support of the scapula is recommended to reliability reduce the acromioclavicular joint.

Biomechanical Analysis of Coracoid Stability After Coracoplasty: How Low Can You Go?

Background: Arthroscopic coracoplasty is a procedure for patients affected by subcoracoid impingement. To date, there is no consensus on how much of the coracoid can be resected with an arthroscopic burr without compromising its stability. Purpose: To determine the maximum amount of the coracoid that can be resected during arthroscopic coracoplasty without leading to coracoid fracture or avulsion of the conjoint tendon during simulated activities of daily living (ADLs). Study Design: Controlled laboratory study. Methods: A biomechanical cadaveric study was performed with 24 shoulders (15 male, 9 female; mean age, 81 ± 7.9 years). Specimens were randomized into 3 treatment groups: group A (native coracoid), group B (3-mm coracoplasty), and group C (5-mm coracoplasty). Coracoid anatomic measurements were documented before and after coracoplasty. The scapula was potted, and a traction force was applied through the conjoint tendon. The stiffness and load to failure (LTF) were determined for each specimen. Results: The mean coracoid thicknesses in groups A through C were 7.2, 7.7, and 7.8 mm, respectively, and the mean LTFs were 428 ± 127, 284 ± 77, and 159 ± 87 N, respectively. Compared with specimens in group A, a significantly lower LTF was seen in specimens in group B (P = .022) and group C (P < .001). Postoperatively, coracoids with a thickness ≥4 mm were able to withstand ADLs. Conclusion: While even a 3-mm coracoplasty caused significant weakening of the coracoid, the individual failure loads were higher than those of the predicted ADLs. A critical value of 4 mm of coracoid thickness should be preserved to ensure the stability of the coracoid process. Clinical Relevance: In correspondence with the findings of this study, careful preoperative planning should be used to measure the maximum reasonable amount of coracoplasty to be performed. A postoperative coracoid thickness of 4 mm should remain.

Double plating is associated with higher fixation strength than single plating in osteoporotic fractures of the scapular spine: a biomechanical study.

INTRODUCTION: The number of atraumatic stress fractures of the scapular spine associated with reverse shoulder arthroplasty is increasing. At present, there is no consensus regarding the optimal treatment strategy. Due to the already weakened bone, fractures of the scapular spine require a high fixation stability. Higher fixation strength may be achieved by double plating. The aim of this study was to evaluate the biomechanical principles of double plating in comparison to single plating for scapular spine fractures. METHODS: In this study, eight pairs (n = 16) of human shoulders were randomised pairwise into two groups. After an osteotomy at the level of the spinoglenoid notch, one side of each pair received fracture fixation with a single 3.5 LCP (Locking Compression Plate) plate. The contralateral scapular spine was fixed with a 3.5 LCP and an additional 2.7 LCP plate in 90-90 configuration. The biomechanical test protocol consisted of 700 cycles of dynamic loading and a load-to-failure test with a servohydraulic testing machine. Failure was defined as macroscopic catastrophic failure (screw cut-out, plate breakage). The focus was set on the results of specimens with osteoporotic bone quality. RESULTS: In specimens with an osteoporotic bone mineral density (BMD; n = 12), the mean failure load was significantly higher for the double plate group compared to single plating (471 N vs. 328 N; p = 0.029). Analysis of all specimens (n = 16) including four specimens without osteoporotic BMD revealed no significant differences regarding stiffness and failure load (p > 0.05). CONCLUSION: Double plating may provide higher fixation strength in osteoporotic bone in comparison to a single plate alone. This finding is of particular relevance for fixation of scapular spine fractures following reverse shoulder arthroplasty. LEVEL OF EVIDENCE: Controlled laboratory study.

Treatment strategies for scapular spine fractures: a scoping review.

Fractures of the scapular spine are relatively rare and can occur without (1) or with (2) association to a reverse shoulder arthroplasty (RSA). To date there are only limited data on the topic. The aim of this scoping review was to identify all available literature and report current treatment concepts.A scoping review was conducted by searching PubMed for relevant studies between 2000 and October 2020. All studies were included which gave detailed descriptions of the treatment strategy.A total of 21 studies with 81 patients were included for the analysis. The mean age over all patients was 62 years (range: 24 to 89 years) and 77% of the patients were female. In 19.8% of cases, the fracture occurred after a traumatic fall from standing height. Eighty-six per cent of the patients had an RSA-associated scapular spine fracture (2). These patients were older compared to group (1) (47 ± 19.6 vs. 76 ± 5.6 years, p = 0.0001) and the majority were female (85%). The majority from group (1) underwent operative treatment with plate fixation. Most patients regained full function and range of motion. RSA-associated fractures (2) were mainly treated non-operatively, with moderate clinical outcome. A high rate of nonunions was reported.Scapular spine fractures without RSA are mainly treated operatively with good clinical results. In association with RSA, scapular spine fractures are mainly treated non-operatively and lead to inferior clinical and radiological results. This scenario seems to be problematic and further research is required to sharpen treatment concepts in this group. Cite this article: EFORT Open Rev 2021;6:788-796. DOI: 10.1302/2058-5241.6.200153.

The forgotten fragment: additional lesser tuberosity fixation of 4-part proximal humeral fractures-a biomechanical investigation.

BACKGROUND: Fractures of the proximal humerus are common. The most frequent surgical treatment option is open reduction and locking plate fixation. Multifragmentary fractures, including 3- and 4-part fractures, are especially challenging to treat because they correlate with an increased risk of fixation failure. In the past, several mechanisms of additional fixation were investigated, but none directly addressed the lesser tuberosity (LT). The goal of this study was to investigate the biomechanical impact of additional anterior fracture fixation in lateral locked plating (LLP) of 4-part proximal humeral fractures (PHFs). METHODS: Twenty-seven fresh frozen human shoulder specimens (mean age, 80 years) with intact rotator cuffs (RCs) were randomized into 4 groups: 3-part PHF with LLP and RC cerclage (n = 6); 4-part PHF with LLP and RC cerclage as standard of care (n = 7); 4-part PHF with LLP, RC cerclage, and 2 anterior 3.5-mm cortical screws (n = 7); and 4-part PHF with LLP, RC cerclage, and additional anterior one-third tubular plate (additional anterior plating [AAP], n = 7). Static load of the RC was simulated with weights. A force-controlled cyclic loading test was performed with a servo-hydraulic testing machine, followed by load-to-failure testing. An optical motion capture system recorded humeral head range of motion. RESULTS: LLP of a 4-part PHF showed more humeral head motion than LLP of a 3-part PHF without fracture of the LT (P < .001). Fixing the LT to the humeral head with two 3.5-mm screws significantly reduced humeral head motion compared with LLP with RC cerclage alone (P < .006). Using AAP significantly increased the construct stiffness compared with the standard of care (P = .03). CONCLUSION: LLP of a 4-part PHF is biomechanically less stable than LLP of a 3-part PHF without fracture of the LT. Additional screw fixation of the LT in 4-part PHFs improves stability compared with LLP alone. In case of metaphyseal comminution, AAP is favorable from a biomechanical perspective.

Glenoid concavity has a higher impact on shoulder stability than the size of a bony defect.

PURPOSE: Surgical treatment of shoulder instability caused by anterior glenoid bone loss is based on a critical threshold of the defect size. Recent studies indicate that the glenoid concavity is essential for glenohumeral stability. However, biomechanical proof of this principle is lacking. The aim of this study was to evaluate whether glenoid concavity allows a more precise assessment of glenohumeral stability than the defect size alone. METHODS: The stability ratio (SR) is a biomechanical estimate of glenohumeral stability. It is defined as the maximum dislocating force the joint can resist related to a medial compression force. This ratio was determined for 17 human cadaveric glenoids in a robotic test setup depending on osteochondral concavity and anterior defect size. Bony defects were created gradually, and a 3D measuring arm was used for morphometric measurements. The influence of defect size and concavity on the SR was examined using linear models. In addition, the morphometrical-based bony shoulder stability ratio (BSSR) was evaluated to prove its suitability for estimation of glenohumeral stability independent of defect size. RESULTS: Glenoid concavity is a significant predictor for the SR, while the defect size provides minor informative value. The linear model featured a high goodness of fit with a determination coefficient of R2 = 0.98, indicating that 98% of the SR is predictable by concavity and defect size. The low mean squared error (MSE) of 4.2% proved a precise estimation of the SR. Defect size as an exclusive predictor in the linear model reduced R2 to 0.9 and increased the MSE to 25.7%. Furthermore, the loss of SR with increasing defect size was shown to be significantly dependent on the initial concavity. The BSSR as a single predictor for glenohumeral stability led to highest precision with MSE = 3.4%. CONCLUSION: Glenoid concavity is a crucial factor for the SR. Independent of the defect size, the computable BSSR is a precise biomechanical estimate of the measured SR. The inclusion of glenoid concavity has the potential to influence clinical decision-making for an improved and personalised treatment of glenohumeral instability with anterior glenoid bone loss.