Biomechanical Design Optimization of Distal Humerus Fracture Plates: A Review.

The goal of this article was to review studies on distal humerus fracture plates (DHFPs) to understand the biomechanical influence of systematically changing the plate or screw variables. The problem is that DHFPs are commonly used surgically, although complications can still occur, and it is unclear if implant configurations are always optimized using biomechanical criteria. A systematic search of the PubMed database was conducted to identify English-language biomechanical optimization studies of DHFPs that parametrically altered plate and/or screw variables to analyze their influence on engineering performance. Intraarticular and extraarticular fracture (EAF) data were separated and organized under commonly used biomechanical outcome metrics. The results identified 52 eligible DHFP studies, which evaluated various plate and screw variables. The most common plate variables evaluated were geometry, hole type, number, and position. Fewer studies assessed screw variables, with number and angle being the most common. However, no studies examined nonmetallic materials for plates or screws, which may be of interest in future research. Also, articles used various combinations of biomechanical outcome metrics, such as interfragmentary fracture motion, bone, plate, or screw stress, number of loading cycles to failure, and overall stiffness (Os) or failure strength (Fs). However, no study evaluated the bone stress under the plate to examine bone "stress shielding," which may impact bone health clinically. Surgeons treating intraarticular and extraarticular distal humerus fractures should seriously consider two precontoured, long, thick, locked, and parallel plates that are secured by long, thick, and plate-to-plate screws that are located at staggered levels along the proximal parts of the plates, as well as an extra transfracture plate screw. Also, research engineers could improve new studies by perusing recommendations in future work (e.g., studying alternative nonmetallic materials or "stress shielding"), clinical ramifications (e.g., benefits of locked plates), and study quality (e.g., experimental validation of computational studies).

Neglected Bicondylar Fracture of the Distal Humerus Treated With Total Elbow Arthroplasty.

A 69-year-old woman suffered a distal humerus fracture including the medial and lateral condyles. She received conservative treatment with a posterior arm splint at a local healthcare center where she was evaluated by a non-specialist physician. Eight months later, she presented to our department complaining about severe instability. An upper limb specialist examined the patient at the time, and after thoroughly explaining the condition, he suggested a surgical approach with total elbow arthroplasty (TEA), which was then performed. At the one-year follow-up, the patient had a full range of motion without any complications or pain complaints. TEA in neglected fractures of the distal humerus is a poorly researched topic in the field of upper limb surgery with only scarce literature available. In this case report, we present the excellent outcomes of the procedure performed on an elderly patient after non-union regaining her quality of life and suggest that TEA can be a viable solution in elderly patients with complicated or non-united elbow fractures.

Does timing of total elbow arthroplasty after distal humerus fracture affect 2-year complication rates?

BACKGROUND: Open reduction internal fixation (ORIF) remains the gold standard for adult distal humerus fractures (DHF). However, indications for total elbow arthroplasty (TEA) continue to expand and the incidence of primary and salvage TEA for DHF has increased. The objective of this study was to compare complication and reoperation rate for acute versus delayed primary and salvage TEA performed for DHF. METHODS: Patients who underwent TEA for DHF were identified in the PearlDiver database. Patients were sorted into three cohorts: (1) acute TEA (within 2 weeks of diagnosis), (2) delayed TEA (between 2 weeks and 6 months after diagnosis), and (3) salvage TEA (after failed ORIF, malunion, nonunion, delayed treatment between 6 months-1 year or post-traumatic arthritis). Multivariate analysis was utilized to assess for confounding variables and covariates when identify differences in complications between cohorts. RESULTS: 788 patients underwent acute TEA, 213 patients underwent delayed TEA, and 422 patients underwent salvage TEA after DHF. The incidence of PJI (8.5% vs. 3.4%, odds ratio (OR) 2.60, P=0.002) and triceps injury (2.4% vs. 0.4%, OR 6.29, P=0.012) were higher in the delayed compared to acute cohort. The incidence of revision (8.5% vs. 2.1%, OR 3.76, P< 0.001), periprosthetic fracture (4.3% vs. 1.1%, OR 3.64, P=0.002), PJI (14.7% vs 3.4%, OR 4.36, P< 0.001), triceps injury (2.6% vs. 0.4%, OR 5.70, P=0.008), and wound complications (6.9% vs 2.9%, OR 2.33, P=0.002) were higher in the salvage compared to acute cohort. There was an increased rate of revision (8.5% vs. 1.9%, OR 6.08, P=0.002) in the salvage compared to delayed cohort. CONCLUSION: Patients undergoing salvage TEA after DHF have increased rates of at 2 years postoperatively including revision, periprosthetic fracture, PJI, triceps injury, and wound complications. The salvage cohort also had an increased risk of revision when compared to the delayed cohort. However, other than revision rates, patients in the salvage and delayed cohorts have similar postoperative complication rates.

Total Elbow Arthroplasty Versus Open Reduction and Internal Fixation for Distal Humerus Fractures: A Propensity Score Matched Analysis of 30-Day Postoperative Complications.

Introduction: Open reduction and internal fixation (ORIF) is an established surgical procedure for distal humeral fractures; however, total elbow arthroplasty (TEA) has become an increasingly popular alternative for elderly patients with these injuries. Using a large sample of recent patient data, this study compares the rates of short-term complications between ORIF and TEA and evaluates complication risk factors. Methods: Patients who underwent primary TEA or ORIF from 2012 to 2021 were identified by Current Procedural Terminology codes in the American College of Surgeons National Surgical Quality Improvement Program database. Propensity score matching controlled for demographic and comorbid differences. The rates of 30-day postoperative complications were compared. Results: A total of 1539 patients were identified, with 1365 (88.7%) and 174 (11.3%) undergoing ORIF and TEA, respectively. Patients undergoing TEA were older on average (ORIF: 56.2 ± 19.8 years, TEA: 74.3 ± 11.0 years, P < .001). 348 patients were included in the matched analysis, with 174 patients in each group. TEA was associated with an increased risk for postoperative transfusion (OR = 6.808, 95% CI = 1.355 - 34.199, P = .020). There were no significant differences in any adverse event (AAE) between procedures (P = .259). A multivariate analysis indicated age was the only independent risk factor for the development of AAE across both groups (OR = 1.068, 95% CI = 1.011 - 1.128, P = .018). Conclusion: The risk of short-term complications within 30-days of ORIF or TEA procedures are similar when patient characteristics are controlled. TEA, however, was found to increase the risk of postoperative transfusions. Risks associated with increasing patient age should be considered prior to either procedure. These findings suggest that long-term functional outcomes can be prioritized in the management of distal humerus fractures.

The 3D-Printed Custom Elbow Prosthesis for Salvage Treatment of Complex Intra-Articular Distal Humerus Fracture Malunion.

Intra-articular fractures of the distal humerus are complex injuries that often require surgery with the goal of restoring elbow range-of-motion and function. Open reduction and internal fixation has been the preferred surgical modality; however, restoration of the medial and/or lateral columns can be complicated in fractures involving a major loss of the articular surface and bony structure. Over the past decade, 3-dimensional (3D) printing has made significant advances in the field of orthopedic surgery, specifically in guiding surgeon preoperative planning. Recently, the incorporation of 3D-printing has proven to provide a safe and reliable construct for the restoration of anatomy in complex trauma cases. We present a 47-year-old woman who sustained a complex, intra-articular distal humerus fracture with associated shearing of the capitellum that went onto malunion. Patient was treated with a patient-specific 3D-printed custom elbow prosthesis with excellent outcomes. Our goal was to shed light on the use of 3D-printing technology as a viable salvage option in treating complex, intra-articular distal humeral fractures associated with lateral condylar damage that subsequently went onto malunion.

Optimal Screw Orientation for Fixation of Coronal Shear Fractures: A Biomechanical Comparison.

OBJECTIVE: Coronal shear fractures of the capitellum are rare injuries which can be challenging to treat. The aim of this study was to compare the biomechanical properties of different internal screw fixation techniques for Dubberley type IA fractures of the capitellum. METHODS: In this biomechanical study, Dubberley type IA fractures of the capitellum were created in 30 human fresh-frozen humeri. The specimens were then divided into three groups: fixation was either performed with 3 x 3.0 mm headless cannulated compression screws (HCCSs) in anteroposterior (AP) orientation (AP group), 3 x 3.0 mm HCCSs in posteroanterior (PA) orientation (PA group) or with 2 x 3.0 mm HCCSs in PA orientation and 1 x 3.0 mm HCCS in lateral orientation (LAT group). Displacement under cyclic loading and ultimate load-to-failure were evaluated in all specimens. RESULTS: There was no significant difference in fragment displacement after 2000 cycles between AP and PA groups (0.8 ± 0.5 mm vs. 0.8 ± 0.6 mm; p = 0.987) or PA and LAT groups (0.8 ± 0.6 mm vs. 0.8 ± 0.3 mm; p = 0.966). LAT group showed the highest load-to-failure (548 ± 250 N) without reaching statistically significant difference to AP group (388 ± 173 N; p = 0.101). There was also no significant difference between AP and PA groups (388 ± 173 N vs. 422 ± 114 N; p = 0.649). CONCLUSIONS: Variations in screw placement had no statistically significant influence on cyclic displacement or load-to-failure in Dubberley Type IA fractures. However, fracture fixation in two planes - both the coronal and the sagittal plane - by adding a screw in a lateral to medial direction may be beneficial to increase primary stability.

Supracondylar Ostectomy and Shortening (S.O.S) for Distal Humerus Nonunions.

INTRODUCTION: Many distal humerus nonunions are associated with bone loss and rigid internal fixation is difficult to obtain, especially for low transcondylar nonunions and those with severe intraarticular comminution. The purpose of this study was to analyze the results of a strategy to address this challenge utilizing internal fixation using the Supracondylar Ostectomy + Shortening (i.e. S.O.S.) procedure for distal humerus nonunions. The goals of this procedure are to (1) optimize bony contact and compression through re-shaping the nonunited fragments at the supracondylar level with selective humeral metaphyseal shortening, (2) maximize fixation using parallel-plating, and (3) provide biologic and structural augmentation with bone graft. MATERIALS AND METHODS: Between 1995 and 2019, 28 distal humerus nonunions underwent internal fixation using the S.O.S. procedure at a single Institution. There were 14 males and 14 females with mean age of 47 (range 14-78) years at the time of the S.O.S procedure and an average of 1.7 prior surgeries. Medical records and radiographs were reviewed to determine rates of union, reoperations, complications, and Mayo Elbow Performance Scores (MEPS). Patients were also prospectively contacted to update their MEPS and gather additional information on complications and reoperations. Mean clinical exam follow-up was 17 months, mean clinical contact follow-up was 19 months, and mean radiographic follow-up was 32 months. RESULTS: Four patients did not have adequate follow-up to determine union. Of the remaining 24 elbows, 22 achieved union. Two elbows developed collapse of the articular surface and were converted to a total elbow arthroplasty (TEA). There were complications in 10 elbows: contracture (5), superficial infection (2), ulnar neuropathy (1), deep infection (1), and hematoma (1). Twelve elbows underwent reoperation: 4 for contracture release, 3 for hardware removal, 2 for total elbow arthroplasty, 1 for bone grafting, 1 for hematoma evacuation, and 1 for ulnar nerve neurolysis. Compared to preoperative data, there was a significant improvement in postoperative flexion, extension and pronation (p<0.01). The mean range of motion was 21° of extension, 119° of flexion, 79° of pronation, and 77° of supination. The mean MEPS was 80 points (range, 25 to 100 points) and 19 elbows (76%) rated as excellent or good. DISCUSSION: Stable fixation and high union rates are possible in distal humerus nonunions with bone loss using a technique that combines supracondylar humeral shortening, parallel plating, and bone grafting. Secondary procedures are commonly needed to restore function in this challenging patient population.

Pseudoarthrosis of the Distal Humerus in Pediatric Osteogenesis Imperfecta Patients: A Case Series and Literature Review.

Osteogenesis imperfecta (OI) is a rare skeletal disorder that increases a patient's susceptibility to bone fracture. One complication commonly associated with fractures in this population is the occurrence of non-union leading to pseudoarthrosis. In this case series, three cases of non-union of the distal humerus leading to pseudoarthrosis in the pediatric OI population are presented. One case presents a successful attempt at treatment, one case presents a failed attempt at treatment, and the third case presents a patient's refusal to get treated. Furthermore, a literature review highlighting other institutions' attempts, successes, and failures at treating this clinical entity is presented. Combining the data retrieved from our institution and others, this review demonstrates that there is currently no standard for treating these patients. Additionally, based on the small case series and literature review presented in this article, definitive guidelines for the treatment of pseudoarthrosis of the distal humerus in pediatric OI patients cannot be outlined. However, our findings suggest that both non-surgical and surgical treatments could be viable options for patients with asymptomatic pseudoarthrosis of the distal humerus.

Malunion of distal humeral fractures: Current concepts.

The incidence of complex articular fractures of the distal humeral in adults has increased and will be growing in the future due to the greater incidence of high-energy trauma and to the higher percentage of the elderly population. Successful treatment is challenging for the needed balance between the stability of often comminuted fractures and early motion. Malunion is a common complication after distal humerus fractures that is influenced by a variety of factors, such as biology, particularly the blood supply of the metaphysis, the nonanatomical reduction of the fracture, the methods of fixation, and mechanical failure. These can involve the intra-articular or extra-articular areas. The clinical presentation may be mainly with pain and instability as for the cubitus varus, or with disfunction and stiffness as for an intra-articular malunion. However, the symptoms will depend on the degree of articular surfaces damage and the degree of deformities in specific planes. The surgical treatment can be challenging, varying from supracondylar osteotomies and re-contouring arthroplasty for extra-articular deformities to interposition arthroplasty, and elbow replacement for intra-articular deformities.

Mid-term results of total elbow arthroplasties in the treatment of geriatric distal humerus fractures.

BACKGROUND: While double plate fixation is the gold standard treatment for distal humerus fractures in the general population, it is the source of many complications in the elderly. Total elbow arthroplasty (TEA) has been proposed as an alternative treatment, with satisfactory short-term functional outcomes. However, little is known about the longevity of the implant and the mid- and long-term complications of this procedure. MATERIALS AND METHODS: A total of 58 TEAs were performed in 57 patients with comminuted distal humerus fractures between September 2008 and September 2019. All patients were clinically (ranges of motion, Mayo Elbow Performance Score [MEPS] and Disabilities of the Arm, Shoulder and Hand [QuickDASH] functional scores) and radiographically assessed. The minimum follow-up was 2years, and the mean follow-up was 4.7years. RESULTS: The overall complication rate was 20.7%, with ulnar nerve damage, complex regional pain syndrome, and severe stiffness being the main complications. The mean MEPS was 85.3, and the mean QuickDASH was 28.1. The mean flexion was 122°, and the mean extension was -23.5°. There were no prosthetic revisions. Of these patients, 17% had radiolucent lines, and 13% had bushing wear at the last follow-up. DISCUSSION: TEA is an effective technique for treating comminuted distal humerus fractures in the geriatric population. The prosthesis's mid-term survivorship was highly satisfactory, with a complication rate that remained low and was generally lower than that of osteosynthesis, with identical functional outcomes. TEAs are indicated in elderly patients, for whom maintaining the fullest possible autonomy is paramount. Our findings suggest that TEAs have sufficient longevity to guarantee a functional, pain-free elbow with no need for reoperation. LEVEL OF EVIDENCE: IV; case series.

Surgical treatment of coronal shear fractures of the distal humerus with an intact lateral epicondyle by the lateral combined approach.

BACKGROUND: Coronal shear fractures of the distal humerus are not only rare and prone to misdiagnosis, but their surgical treatment can be challenging. We aimed to investigate the feasibility of exposing distal humeral coronal shear fractures with a combined lateral approach that preserves the extensors and lateral ulnar collateral ligament (LUCL) and to analyze the clinical efficacy of open reduction and internal fixation (ORIF) in the treatment of these injuries. METHODS: We included 45 patients who sustained coronal shear fractures of the distal humerus with the lateral epicondyle intact and were treated with ORIF from January 2013 to August 2020. The fractures were exposed by the lateral combined approach in which the tendons involving the common extensor, the extensor carpi ulnaris (ECU), and the LUCL were preserved. Two observation windows were formed anterior to and posterior to these tendons and the LUCL was used to achieve fracture reduction. Countersunk screws, with or without a plate placed on the posterior lateral condyle, were used to fix the fragments. The functional outcomes of these patients were reviewed and assessed with physical and radiographic examinations, range of motion (ROM) measurements, and self-evaluation Mayo Elbow Performance Index (MEPI) and Disabilities of the Arm, Shoulder, and Hand (DASH) scores. RESULTS: In total, 40 patients were followed up with for over 1 year and were included in the final analysis. The mean follow-up duration was 42±30 months (range, 12-107 months). The patients' mean age was 42 years (range, 14-74 years). According to the Dubberley Classification, there were 15 type I, 17 type II, and 8 type III fractures. At the final follow-up, the mean flexion-extension arc was 131° (range, 65-150) and mean pronation and supination was 73° (range, 45-80) and 71° (range, 40-80), respectively. The mean MEPI score was 88 (range, 61-97) points; the results were excellent in 21, good in 13, fair in 4, and poor in 2 patients. The mean DASH score was 11 (range, 0-42) points. Neither functional score nor range of movement was associated with age, sex, fracture type, injury type, or surgical timing. CONCLUSION: Reduction and stable fixation with internal fixation for coronal shear fractures of the distal humerus can be achieved by the lateral combined approach. Early functional mobilization allows for satisfactory restoration of elbow function.

Integrated Physical Therapy in a Unique Case of Holstein-Lewis Fracture With Radial Palsy: A Case Report.

The term "Holstein-Lewis fracture" describes a spiral fracture that occurs in the shaft of the humerus at its distal third, which has been linked to radial nerve palsy in adults, and operative treatment is the preferred method of treating the trapped nerve at the fracture site. This paper describes a clinical case involving a 20-year-old male patient demonstrating a humeral fracture syndrome accompanied by complications associated with radial nerve palsy. After the necessary investigation, he was diagnosed with a Holstein-Lewis fracture with radial nerve paralysis; he underwent open reduction internal fixation (ORIF), after which he was referred to physical therapy. Developing a successful postoperative rehabilitation program that consists mostly of functional physical therapy interventions is essential for the treatment of this condition. Outcome measures like the Numerical Pain Rating Scale (NPRS), Disabilities of the Arm, Shoulder, and Hand (DASH) score, and Patient-Rated Wrist Evaluation (PRWE) score were recorded before and after rehabilitation, and pain reduction, improvement in strength, range of motion (ROM), grip strength, and activities of daily living (ADL) were found. The purpose of this case report is to present a comprehensive treatment plan that includes ROM exercises, cryotherapy, and strengthening of grip using a robotic glove for a patient who had a wrist drop and underwent ORIF surgery. This tailored intervention was effective in speeding up the return of functional abilities and improving function in ADLs.

A systematic review of the treatment of distal humerus fractures in older adults: A comparison of surgical and non-surgical options.

Background: Fractures of the distal humerus are a common fragility fracture in older adults. The purpose of this study was to systematically review the literature to produce pooled estimates of the outcomes of treatment using total elbow arthroplasty (TEA), open reduction and locking plate fixation (ORIF), hemiarthroplasty or with conservative management. Methods: A systematic review of PUBMED and EMBASE databases was conducted for studies reporting outcomes of intra-articular fractures in older adults. Data extracted included patient-reported outcome measures as well as clinical outcomes including ROM, adverse events and all-cause reoperation rates. Results: Forty-eight studies met the inclusion criteria and included 1838 acute, intra-articular distal humeral fractures. There was no clinically important difference in patient-reported pain and function measured on the Mayo Elbow Performance Score (TEA = 89.3 (SD 20.0), Hemi = 88.4 (SD 10.6), internal fixation = 85.0 (SD 14.7), non-operative = 85.1 (SD 11.0)). Discussion: Each of the treatment modalities studies resulted in a reasonable level of elbow function. The included studies were largely non-comparative and at considerable risk of bias. As elbow replacement surgery becomes centralised in the UK, there is a real need for high-quality comparative research studies to inform practice.

Utility of three-dimensional printing in the surgical management of intra-articular distal humerus fractures: a systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: Clinical outcomes after fixation of distal humerus intraarticular fractures are directly related to the quality of reduction. The use of three-dimensional (3D)-printed fracture models can benefit preoperative planning to ensure good reduction. This review aims to determine if surgery performed with 3D printing assistance are faster and result in fewer complications and improved clinical outcomes than conventional methods. We also outline the benefits and drawbacks of this novel technique in surgical management of distal humerus fractures. METHODS: A systematic literature search was carried out in various electronic databases. Search results were screened based on title and abstract. Data from eligible studies were extracted into spreadsheets. Meta-analysis was performed using appropriate computer software. RESULTS: Three randomized controlled trials with 144 cases were included in the final analysis. The 3D-printed group had significantly shorter mean operating time (mean difference, 16.25 minutes; 95% confidence interval [CI], 12.74-19.76 minutes; P<0.001) and mean intraoperative blood loss (30.40 mL; 95% CI, 10.45-60.36 mL; P=0.005) compared with the conventional group. The 3D-printed group also tended to have fewer complications and a better likelihood of good or excellent outcomes as per the Mayo elbow performance score, but this did not reach statistical significance. CONCLUSIONS: Three-dimensional-printing-assisted surgery in distal humerus fractures has several benefits in reduced operating time and lower blood loss, indirectly decreasing other complications such as infection and anemia-related issues. Future good-quality studies are required to conclusively demonstrate the benefits of 3D printing in improving clinical outcomes. Level of evidence: I.

The importance of interdigitating screw fixation of the trochlea in double plate osteosynthesis of low transcondylar distal humerus fractures: A biomechanical study.

OBJECTIVE: The trochlea is of great importance for the stability of the elbow and its fixation in low transcondylar fractures of the distal humerus is especially challenging. The aim of this study was to determine the optimal trochlea fixation in double plate osteosynthesis of intraarticular distal humerus fractures. METHODS: A low transcondylar, C3-type distal humerus fracture was created in 20 fresh-frozen human cadaveric humeri. The samples were then randomly divided into two groups of 10 specimens each. Double plate osteosynthesis was performed in both groups. In group A, the two most distal screws of the lateral plate were inserted into the trochlea fragment. In group B, these screws did not extend into the trochlea. Displacement under cyclic loading and ultimate failure loads were determined for all specimens. RESULTS: Group A showed significantly less displacement under cyclic loading in each measurement interval (0.92 mm vs. 1.53 mm after 100 cycles, p = 0 0.006; 1.10 mm vs. 1.84 mm after 1000 cycles, p = 0.007; 1.18 mm vs. 1.98 mm after 2000 cycles, p = 0.008). The ultimate failure load was significantly higher in group A than in group B (345.61 ± 120.389 N vs. 238.42 ± 131.61 N, p = 0.037). CONCLUSIONS: Fixation of the trochlea with interdigitating screws in double plate osteosynthesis of low-condylar type C distal humerus fractures results in superior construct stability. LEVEL OF EVIDENCE: not applicable (biomechanical).

Development of a diagnostic support system for distal humerus fracture using artificial intelligence.

PURPOSE: AI has shown promise in automating and improving various tasks, including medical image analysis. Distal humerus fractures are a critical clinical concern that requires early diagnosis and treatment to avoid complications. The standard diagnostic method involves X-ray imaging, but subtle fractures can be missed, leading to delayed or incorrect diagnoses. Deep learning, a subset of artificial intelligence, has demonstrated the ability to automate medical image analysis tasks, potentially improving fracture identification accuracy and reducing the need for additional and cost-intensive imaging modalities (Schwarz et al. 2023). This study aims to develop a deep learning-based diagnostic support system for distal humerus fractures using conventional X-ray images. The primary objective of this study is to determine whether deep learning can provide reliable image-based fracture detection recommendations for distal humerus fractures. METHODS: Between March 2017 and March 2022, our tertiary hospital's PACS data were evaluated for conventional radiography images of the anteroposterior (AP) and lateral elbow for suspected traumatic distal humerus fractures. The data set consisted of 4931 images of patients seven years and older, after excluding paediatric images below seven years due to the absence of ossification centres. Two senior orthopaedic surgeons with 12 + years of experience reviewed and labelled the images as fractured or normal. The data set was split into training sets (79.88%) and validation tests (20.1%). Image pre-processing was performed by cropping the images to 224 × 224 pixels around the capitellum, and the deep learning algorithm architecture used was ResNet18. RESULTS: The deep learning model demonstrated an accuracy of 69.14% in the validation test set, with a specificity of 95.89% and a positive predictive value (PPV) of 99.47%. However, the sensitivity was 61.49%, indicating that the model had a relatively high false negative rate. ROC analysis showed an AUC of 0.787 when deep learning AI was the reference and an AUC of 0.580 when the most senior orthopaedic surgeon was the reference. The performance of the model was compared with that of other orthopaedic surgeons of varying experience levels, showing varying levels of diagnostic precision. CONCLUSION: The developed deep learning-based diagnostic support system shows potential for accurately diagnosing distal humerus fractures using AP and lateral elbow radiographs. The model's specificity and PPV indicate its ability to mark out occult lesions and has a high false positive rate. Further research and validation are necessary to improve the sensitivity and diagnostic accuracy of the model for practical clinical implementation.

Dual plating in the metastatic distal humerus: Benefits may outweigh the risks.

Background: Impending and complete pathologic fractures of the distal humerus are rare complications of metastatic cancer. Surgical treatment aims to quickly restore function and minimize pain. Plate and screw fixation (PSF) is a common method for addressing these lesions, but unlike in orthopaedic trauma, there are no clear guidelines for best management. While dual PSF theoretically provides better support and reduces the chance of reoperation due to tumor progression, single PSF is currently the more common choice. Materials and methods: Between March 2008 and September 2021, 35 consecutive patients who underwent PSF for distal humerus metastasis or multiple myeloma were retrospectively reviewed. The proportion of patients who developed various postoperative complications, including infection, nonunion, deep vein thrombosis, tumor progression, and radial nerve palsy, as well as those requiring reoperation, was calculated. Mann-Whitney U test, Pearson's chi-squared, and Fisher's exact test were used to investigate differences between the single and dual PSF groups with statistical significance defined as p ≤ 0.05. Results: There was no significant difference (p = 0.259) in revision rate, although 3 of 21 (14.3 %) single PSF patients required reoperation compared to 0 of 14 (0.0 %) dual PSF patients. The revisions were performed in one patient due to refracture and in two patients due to tumor progression. Although not statistically significant, a larger percentage of single PSF patients developed a postoperative complication compared to dual PSF patients [odds ratio 0.42 (95 % confidence interval 0.071 to 2.5); p = 0.431]. Single PSF did lead to shorter operative time compared to dual PSF [p < 0.001]. Conclusion: Dual PSF is non-inferior to single PSF and potentially results in fewer reoperations and postoperative complications in distal humerus pathologic lesions, although it leads to longer operative time. The current study is limited by small sample size due to the rarity of distal humerus metastatic lesions.

Weak Points of Double-Plate Stabilization Used in the Treatment of Distal Humerus Fracture through Finite Element Analysis.

BACKGROUND: Multi-comminuted, intra-articular fractures of the distal humerus still pose a challenge to modern orthopedics due to unsatisfactory treatment results and a high percentage (over 50%) of postoperative complications. When surgical treatment is chosen, such fractures are fixed using two plates with locking screws, which can be used in three spatial configurations: either parallel or one of two perpendicular variants (posterolateral and posteromedial). The evaluation of the fracture healing conditions for these plate configurations is unambiguous. The contradictions between the conclusions of biomechanical studies and clinical observations were the motivation to undertake a more in-depth biomechanical analysis aiming to indicate the weak points of two-plate fracture stabilization. METHODS: Research was conducted using the finite element method based on an experimentally validated model. Three variants of distal humerus fracture (Y, λ, and H) were fixed using three different plate configurations (parallel, posterolateral, and posteromedial), and they were analyzed under six loading conditions, covering the whole range of flexion in the elbow joint (0-145°). A joint reaction force equal to 150 N was assumed, which corresponds with holding a weight of 1 kg in the hand. The biomechanical conditions of bone union were assessed based on the interfragmentary movement (IFM) and using criteria formulated by Steiner et al. Results: The IFMs were established for particular regions of all of the analyzed types of fracture, with distinction to the normal and tangential components. In general, the tangential component of IFM was greater than normal. A strong influence of the elbow joint's angular position on the IFM was observed, with excessive values occurring for flexion angles greater than 90°. In most cases, the smallest IFM values were obtained for the parallel plaiting, while the greatest values were obtained for the posteromedial plating. Based on IFM values, fracture healing conditions in particular cases (fracture type, plate configuration, loading condition, and fracture gap localization) were classified into one of four groups: optimal bone union (OPT), probable union (PU), probable non-union (PNU), and non-union (NU). CONCLUSIONS: No plating configuration is able to ensure distal humerus fracture union when the full elbow flexion is allowed while holding a weight of 1 kg in the hand. However, flexion in the range of 0-90° with such loadings is acceptable when using parallel plating, which is a positive finding in the context of the early rehabilitation process. In general, parallel plating ensures better conditions for fracture healing than perpendicular plate configurations, especially the posteromedial version.

Treatment of distal third humeral shaft fractures with posterior minimally invasive plate osteosynthesis (MIPO) with segmental isolation of the radial nerve: minimum one-year follow-up.

Background: Open reduction and internal fixation with plate is one of the most widely used treatments for distal third humeral shaft fractures. The purpose of this study was to report the outcomes of the treatment of distal third humeral shaft fractures with posterior minimally invasive plate osteosynthesis (MIPO) with segmental isolation of the radial nerve. Methods: We performed an observational, retrospective, consecutive, monocentric, continuous multioperator study. We reviewed 22 distal third humeral shaft fractures treated with posterior MIPO in our institution with an extra-articular distal humerus plate from 2018 to 2021. Inclusion was limited to functionally independent patients with displaced fractures involving the junction of the middle and distal thirds of the humerus and minimum 12-month follow-up for implant removal. We assessed clinical outcomes including range of motion; QuickDASH score; Mayo Elbow Performance Score; and Constant-Murley score. Results: The average follow-up period of the sample was 31.7 ± 11.6 months (range, 15.7-51.3 months). The average elbow flexion and extension were 146.4° ± 7.3° (range, 120°-150°) and -0.7° ± 3.3° (range, -15° to 0°), respectively. The average shoulder anterior flexion, elevation, and abduction were 178.6° ± 3.6° (range, 170°-180°), 179.1° ± 2.9° (range, 170°-180°), and 140.9° ± 14.8° (range, 110°-160°), respectively. The average external rotation was 88.6° ± 6.4 (range, 65°-90°). The mean visual analog scale score for pain was 1.0 ± 1.6 (range, 0-5) and the mean Mayo Elbow Performance Score was 90.5 ± 9.9 (range, 70-100). The mean QuickDASH and Constant-Murley scores were 4.7 ± 6.8 (range, 0-20.5) and 95.5 ± 5.1 (range, 81-100), respectively. Two patients presented with relevant compromise of radial nerve motor function postoperatively (M3 and M2; the more compromised was preoperative injury). All patients recovered radial nerve neuropraxia within six weeks postoperatively. All fractures achieved union. The average anteroposterior and lateral axis were 175.0 ± 3.6 (168.0°-180.0°) and 177.5 ± 2.0 (173.0°-180.0°), respectively. No superficial or deep infection was reported. No cases of re-displacement of fracture, implant failure, or any other implant-related complication in follow-up were reported. No patient required plate withdrawal. Conclusion: The results of this study demonstrate that the posterior MIPO technique is a reliable option for treating distal third shaft humeral fractures. The radial nerve must be identified and protected in all cases to prevent palsy.