Anatomy and biomechanics of the elbow

An Observational Study of Clinico-radiological Co-relation of Carrying Angle in Children

Introduction

The purpose of this study is to establish the correlation of clinically measured carrying angle with four radiological angles, i.e., Humerus-Elbow-Wrist angle (HEWA), Humero-ulnar angle, Metaphyseal-Diaphyseal angle, and Baumann's angle, and to find out which of the above-mentioned angles co-relates best with the clinically measured carrying angle.

Methods

We studied 100 patients in the age group of 2-12 years after Ethics committee approval and informed consent from parents. Clinical angle was measured using goniometer and radiological angles marked on antero-posterior elbow X-ray using a standard method. Collected data were studied using statistical tests to find out correlation.

Results

Pearson correlation coefficient for humerus-elbow-wrist angle found to be 0.674 followed by Humero-Ulnar angle (r = 0.417). Regression coefficient for humerus-elbow-wrist angle is 0.635 (p value < 0.001).

Conclusion

Humerus-Elbow-Wrist angle correlates better compared to other radiological angles in assessment of varus-valgus angulations of elbow & will not only play a vital role in pre- operative planning of deformity corrections but also in the evaluation & comparison of the post-operative functional outcomes.

Proximal radioulnar joint, but not posterolateral, instability in patients with symptomatic minor instability of the lateral elbow

BACKGROUND

The elbow joint is stabilized laterally by a complex of bony and ligamentous structures, such as the lateral ulnar collateral ligament and radial lateral collateral ligament (RLCL). Pathogenesis of many elbow conditions like symptomatic minor instability of the lateral elbow (SMILE) is based on ligamentous incompetency. The aim of this study is to measure ligament elongation in SMILE patients and determine the correlation with the development of this pathologic condition.

MATERIALS AND METHODS

Twenty-eight patients were included in this study: half of them were operated for suspected SMILE whereas the others were affected by other elbow diseases. All the patients underwent elbow arthroscopy. During this procedure, 4 parameters were analyzed: annular drive through (ADT), ulnar-humeral stressed distance (UHSD) at 45° and 30° of flexion, and loose collar sign (LCS). A dedicated arthroscopic mini-spreader introduced through an arthroscopic portal was used to take measurements.

RESULTS

Statistically significant differences were found for LCS (P = .0003) and ADT (P = .000002). UHSD at 30° and 45° elbow flexion was slightly higher in SMILE patients, but not significantly.

DISCUSSION AND CONCLUSIONS

Progressive stretching of the RLCL and annular ligament may lead to their elongation, resulting in a pathologic anteroposterior shifting of the radial head and a lower congruence between the inner surface of the annular ligament and the radial head cartilage, resulting in proximal radioulnar instability. The study shows how RLCL and annular ligament are elongated in SMILE patients compared with controls, causing instability of the proximal radioulnar joint and confirming that ligament incompetency is involved in the SMILE condition.

What do we need to address when we treat neglected Monteggia fracture in children

Monteggia fracture is a relatively uncommon injury in pediatric patients, accounting for less than 2% of forearm fractures, characterized by a combination of ulna fracture and radial head dislocation. Neglected Monteggia fractures define as those that have not received treatment within 3 weeks. In children, ulna fractures are easily diagnosed while radial head dislocation may be overlooked, necessitating open reduction after neglecting the Monteggia fracture and potentially causing additional trauma to the child. This study aims to review the pathological characteristics of neglected Monteggia fractures based on the length ratio of the ulna and radius, relative positions between the proximal ends of the ulna and radius, the integrality of annular ligament and the pathological change of proximal radioulnar joint. The findings will provide valuable insights and guidance for managing neglected Monteggia fractures.

Microstructure of the radial head: Insights into anatomical variations and implications for advanced interventions

Appropriate management of radial head fractures is integral to prevent long-term consequences like chronic pain and loss of motion. Advanced imaging systems, like micro-computed tomography (μCT), are valuable for understanding radial head fracture patterns as they utilize micrometer scale resolution to define important parameters of bone health like cortical density and trabecular thickness. The purpose of this study was to identify and describe the structural morphology of the radial head utilizing μCT. Nine fresh-frozen cadaveric human radii were divided into four equal quadrants, based, and labeled as posteromedial, posterolateral, anteromedial, and anterolateral. Quadrants were scanned with a SCANCO MicroCT40 with both cortical and cancellous bone density measurements at a resolution of 36.0 μm. Bone density, direct trabecular number, and trabecular thickness were recorded as milligrams of hydroxyapatite/cm3. A one-way repeated measures ANOVA was performed to compare the bone densities, trabecular number, and trabecular thickness of each of the four quadrants (p < 0.05). The posteromedial quadrant contained substantially more bone than other quadrants. Significantly greater bone densities were found in the posteromedial quadrant (148.1 mg of HA/cm3) compared to the anteromedial quadrant (54.6 mg of HA/cm3), posterolateral quadrant (137.5 mg of HA/cm3) compared to the anteromedial quadrant (54.6 mg of HA/cm3), and posterolateral quadrant (137.5 mg of HA/cm3) compared to the anterolateral quadrant (58.1 mg of HA/cm3). The trabecular number was not significantly different between quadrants. Trabecular thickness was significantly lower in the anterolateral (0.1417 mg of HA/cm3) and anteromedial (0.1416 mg of HA/cm3) quadrants compared to the posteromedial (0.1809 mg of HA/cm3) quadrant. The posterior half of the radial head was found to have a higher density of columns and arches compared to the anterior half. The microstructure of trabecular bone in the distal radius forms columns, struts, and arches, which allow for efficient transmission of stress through the bone. The microstructure of the radial head has similar microarchitecture to the distal radius with the present study identifying the presence of columns and arches in the radial head. These structures, along with trabecular density, in the posterior radial head may explain the lower incidence of fractures involving the posterior half of the radial head. Furthermore, our study supports the idea that the high incidence of fractures involving the anterolateral quadrant is due to microarchitecture characteristics and the relative lack of supportive structures compared to other areas. The novel insight gained from this study will aid in the development of advanced interventions for preventative measures and better treatment of radial head fractures like more satisfactory purchase when screws are directed towards the denser posteromedial quadrant.

Coronoid fractures and complex elbow instability: current concepts

Fractures of the coronoid process typically occur as part of more complex injury patterns, such as terrible triads, trans-olecranon fracture-dislocations, posteromedial rotatory injuries or Monteggia-like lesions. Each pattern is associated with a specific type of coronoid fracture with regard to shape and size and specific soft-tissue lesions. O' Driscoll classification incorporates those associations identifying three major types of fractures: tip, anteromedial facet, and basal fractures. The objective of this study is to review the most common types of complex elbow instability, identify the indications for coronoid fixation and guide the appropriate management. Tip fractures as those seen in terrible triads can conditionally left untreated provided that elbow stability has been restored after radial head fixation and ligaments repair. Anteromedial facet fractures benefit from a buttress plate, while large basilar fractures can be effectively secured with posteroanterior screws. Coronoid reconstruction with a graft should be considered in post-traumatic cases of chronic coronoid deficiency.

Automated Determination of Morphometric Parameters of the Human Radius Based on the Results of Its Computed Tomography

A fundamentally new software method for automated measurement of morphometric parameters of computed tomographic image of the human radius has been designed. The parameters obtained by manual morphometry of computed tomograms using the RadiAnt DICOM Viewer software were compared with the results of the software product developed by us. The relative error in the measurement of morphometric parameters was about 10%. In the future, the presented software method of automated determination of morphometric parameters of the bone will enable modeling of individual prosthesis of the head of the radius based on the results of computed tomograms with consideration of the structural features of the human radius.

Reconstruction of the proximal radius with 3D-printed personalized prosthesis after tumor resection: case series

BACKGROUND

Giant cell tumor of bone (GCTB) (Campanacci III) or malignant tumors extend to the epiphyseal region of the proximal radius, and intra-articular resection of the proximal radius is often needed. In the present study, we present the patients who underwent reconstruction of the proximal radius with 3D-printed personalized prosthesis after tumor resection, aiming to describe the prosthesis design and surgical technique and evaluate the clinical outcomes of this method.

METHODS

Between November 2018 and January 2021, 9 patients received radial hemiarthroplasty with 3D-printed personalized prostheses after tumor resection. The pathologic diagnosis was GCTB (Campanacci III) in 7 patients, osteosarcoma (IIB) in 1 patient, and synovial sarcoma (IIB) in 1 patient. The range of motion (ROM) and strength in terms of elbow flexion/extension and forearm supination/pronation were evaluated. Pain was assessed by the visual analog scale (VAS) preoperatively and at each follow-up visit. To evaluate the functional outcome, the Mayo Elbow Performance Score (MEPS) system and the Musculoskeletal Tumor Society (MSTS) scoring system were administered at each follow-up visit. Complications and oncological outcomes were recorded.

RESULTS

The patients were followed from 24 to 51 months, with a median follow-up of 35 months. No patients were lost to follow-up. During the follow-up, local recurrence and metastasis were not observed. The VAS score improved from a median of 5 points (range 4-7) preoperatively to 1 point (range 0-2) at the last follow-up visit. The mean MEPS score was 88.5% (83-93), and the mean MSTS score was 25.3 (24-27) at the last follow-up visit. No complications such as infection and aseptic loosening were detected.

CONCLUSIONS

The implantation of a 3D-printed personalized prosthesis after proximal radial resection showed excellent oncologic outcomes and postoperative function at short-term follow-up and is a viable alternative method for reconstruction of the proximal radius bone defect after tumor resection.

Treatment strategies for simple elbow dislocation - a systematic review

BACKGROUND

Current treatment concepts for simple elbow dislocation involve conservative and surgical approaches. The aim of this systematic review was to identify the superiority of one treatment strategy over the other by a qualitative analysis in adult patients who suffered simple elbow luxation.

STUDY DESIGN

A systematic review in accordance with the PRISMA guidelines and following the suggestions for reporting on qualitative summaries was performed. A literature search was conducted using PubMed and Scopus, including variations and combinations of the following keywords: elbow, radiohumeral, ulnohumeral, radioulnar, luxation, and therapy. Seventeen studies that performed a randomized controlled trial to compare treatment strategies as conservative or surgical procedures were included. Reviews are not selected for further qualitative analysis. The following outcome parameters were compared: range of motion (ROM), Mayo Elbow Performance Score (MEPS), Disabilities of the Arm, Shoulder and Hand outcome measure (Quick-DASH), recurrent instability, pain measured by visual analog scale (VAS) and time to return to work (RW).

RESULTS

Early mobilization after conservative treatment strategies showed improved ROM compared to immobilization for up to 3 weeks after surgery with less extension deficit in the early mobilization group (16° ± 13°. vs. 19.5° ± 3°, p < 0.05), as well as excellent clinical outcome scores. Surgical approaches showed similar results compared to conservative treatment, leading to improved ROM (115 vs. 118 ± 2.8) and MEPS: 95 ± 7 vs. 92 ± 4.

CONCLUSION

Conservative treatment with early functional training of the elbow remains the first-line therapy for simple elbow dislocation. The surgical procedure provides similar outcomes compared to conservative treatment regarding MEPS and ROM for patients with slight initial instability in physical examination and radiographs. People with red flags for persistent instability, such as severe bilateral ligament injuries and moderate to severe instability during initial physical examination, should be considered for a primary surgical approach to prevent recurrent posterolateral and valgus instability. Postoperative early mobilization and early mobilization for conservatively treated patients is beneficial to improve patient outcome and ROM.

[Radial Head Replacement: Management of Elbow and Forearm Instability after Comminuted Radial Head Fractures Associated with Elbow Dislocation]

PURPOSE OF THE STUDY

This manuscript aims to identify an indication algorithm for the surgical treatment of radial head fractures associated with elbow dislocation. The study compares the mid-term functional outcomes of patients with multifragment radial head fracture treated by resection with the outcomes of patients treated with radial head replacement.

MATERIAL AND METHODS

The cohort of 34 patients who sustained a radial head fracture at the mean age of 42.5 years (age range 20-81 years) was broken down into two groups by type of surgery. The EXT group consists of 20 patients with the radial head fracture treated by radial head resection. The END group includes 14 patients treated with the radial head replacement. In all patients, the radial head fracture was associated with elbow dislocation (type IV fracture according to the Mason-Johnston classification). The modified Kocher's surgical approach was used in all patients of both the groups. In the EXT group, resection of the fragmented radial head was performed. In the END group, the ExploR® Modular Radial Head System (Zimmer, Biomet, USA) was used, consisting of a CoCr (cobalt chromium) alloy head and a titanium stem. The pain and the range of motion of the elbow and forearm were evaluated after the completion of the outpatient rehabilitation (the mean follow-up period was 2.4 years). Simultaneously, the elbow joint stability was assessed. Radiographs were taken to detect heterotopic ossifications, proximalization of the radius, and any signs of prosthesis loosening. The frequency of reoperations was followed-up. The MEPS (Mayo Elbow Performance Score) was calculated.

RESULTS

In the EXT group, the mean elbow flexion was 117.5° and the mean pronation/supination was 166.9°. In 50% of patients, the MEPS obtained was greater than 90 points, which means an excellent functional outcome. In 1 patient (5%), recurrent elbow dislocation occurred which was the reason for revision surgery (elbow transfixation with the Kirschner wires and medial collateral ligament suture). Revision surgery was also performed in 2 patients (10%) in whom not all the radial head fragments were removed. Moreover, also observed was elbow joint instability (2 patients) and temporary radial nerve paralysis (1 patient). In 1 case discrete proximalization of the radius developed. The patients in the END group showed the mean elbow flexion of 112° and the mean pronation/supination of 135°. The MEPS obtained from 69% of patients was greater than 90 points, which means an excellent outcome. The pain under load was reported by 3 patients (21%). In 5 patients (35%), the X-rays showed radiolucent zone around the stem of the prosthesis. Neither revision surgery, nor prosthesis removal has been performed yet in any patient. No instability, neurological complications or infections have been reported. In both EXT and END group heterotopic ossifications have developed in 4 patients.

CONCLUSIONS

Radial head replacement compared to the radial head resection in the management of multifragment fractures associated with elbow dislocations increase the elbow and forearm stability. The group of patients with an implanted radial head prosthesis shows a higher percentage of patients achieving excellent functional outcome than the group of patients with radial head resection.

KEY WORDS

radial head, elbow, fracture, dislocation, resection, prosthesis.

Demographic heterogeneity in valgus angulation of the proximal ulnar canal in relation to the flexion-extension axis

BACKGROUND

The long-term outcome of total elbow arthroplasty remains unsatisfactory because of loosening and polyethylene wear, which could be caused by malpositioning of the ulnar component. When introducing an ulnar component, 2 different angles should be considered in the coronal plane: the valgus angulation of the proximal ulna in relation to the flexion-extension axis (FE-axis) and the intramedullary varus angulation in relation to the FE-axis. Currently, available TEA designs may not always be able to reconstruct the FE-axis because of the morphologic variability of the ulna.

HYPOTHESIS

This study aimed to determine the demographic variability of the ulna and the relation between the 2 angulations in the frontal plane based on 3-dimentional computed tomography (CT) reconstructions of the elbow joint of healthy volunteers.

METHODS

Computed tomography scans of 36 left elbows of healthy volunteers were obtained (20 men and 16 women). The scans were segmented and analyzed using the Mimics Research 20.0 software. A local coordinate system was created based on the FE-axis of the elbow and the ulna's longitudinal axis. The measurements were conducted using the 3-Matic Research 12.0 software.

RESULTS

The valgus angulation of the proximal medullary canal was on average 16° in men but 12° in women and ranged between 5° and 21°. The varus angulation of the medullary cavity could be determined at 57 mm in men and 64 mm in women from the FE-axis. This angulation was on average 10° in men and 7° in women. There was no significant correlation between this angle and the length of the ulna or the point of varus angulation.

CONCLUSION

This study found a wide range of valgus angulation of the proximal ulnar canal in relation to the FE-axis. The available elbow implant designs are discordant with the mean valgus angulation of the proximal ulna found in this study, and the valgus laxity of the implants does not cover the variability in the population.

Simple lateral elbow dislocation: A case report

BACKGROUND

Simple lateral elbow dislocation (SLED) is a rare type of elbow dislocation; however, its treatment may be complicated by accompanying soft tissue or neurovascular damage. Herein, we report a rare case of SLED managed secon-darily with open reduction and soft tissue repair following failure of closed reduction.

CASE SUMMARY

A 67-year-old woman suffered SLED after falling on her outstretched left hand with her elbow extended. She developed pain, swelling, and movement restriction in the elbow; there were no neurovascular symptoms, except for numbness in the 4^th and 5^th digits. Radiologic investigation confirmed the SLED, and a closed reduction under anesthesia was performed. The follow-up radiographs at 1-wk revealed failure of reduction; accordingly, open reduction with lateral collateral ligament and common extensor origin repair were carried out. The patient regained full elbow range of motion by six weeks.

CONCLUSION

Adequate concentric reduction for SLED, conservatively or surgically, reduces complications and provides a more functional joint.

A combined experimental and finite element analysis of the human elbow under loads of daily living

Elbow trauma is often accompanied by a loss of independence in daily self-care activities, negatively affecting patients' quality of life. Finite element models can help gaining profound knowledge about native human joint mechanics, which is crucial to adequately restore joint functionality after severe injuries. Therefore, a finite element model of the elbow is required that includes both the radio-capitellar and ulno-trochlear joint and is subjected to loads realistic for activities of daily living. Since no such model has been published, we aim to fill this gap. For comparison, 8 intact cadaveric elbows were subjected to loads of up to 1000 N, after they were placed in an extended position. At each load step, the displacement of the proximal humerus relative to the distal base plate was measured with optical tracking markers and the joint pressure was measured with a pressure mapping sensor. Analogously, eight finite element models were created based on subject-specific CT scans of the corresponding elbow specimens. The CT scans were registered to the positions of tantalum beads in the experiment. The optically measured displacements were applied as boundary conditions. We demonstrated that the workflow can predict the experimental contact pressure distribution with a moderate correlation, the experimental peak pressures in the correct joints and the experimental stiffness with moderate to excellent correlation. The predictions of peak pressure magnitude, contact area and load share on the radius require improvement by precise representation of the cartilage geometry and soft tissues in the model, and proper initial contact in the experiment.

Current concepts in the management of "Terrible Triad" injuries of the elbow

Terrible triad injuries of the elbow are complex injuries which can result in long term complications and significant disability. They must be identified correctly, and managed appropriately in order to maximise functional outcomes. A clear understanding of the bony and ligamentous anatomy is essential to plan appropriate surgical reconstruction to provide elbow stability. Urgent reduction of the elbow, followed by 3-dimensional imaging and surgical repair or replacement of the injured structures is the mainstay of treatment in the majority of cases. This review presents a summary of the relevant anatomy and the evidence for the management of these complex injuries.

Lateral Humeral Condyle Fractures in Pediatric Patients

Lateral humeral condyle fractures are frequently seen in pediatric patients and have a high risk of unfavorable outcomes. A fall on the outstretched arm with supination of the forearm is the most common trauma mechanism. A physical examination combined with additional imaging will confirm the diagnosis. Several classifications have been described to categorize these fractures based on location and comminution. Treatment options depend on the severity of the fracture and consist of immobilization in a cast, closed reduction with percutaneous fixation, and open reduction with fixation. These fractures can lead to notable complications such as lateral condyle overgrowth, surgical site infection, pin tract infections, stiffness resulting in decreased range of motion, cubitus valgus deformities, 'fishtail' deformities, malunion, non-union, avascular necrosis, and premature epiphyseal fusion. Adequate follow-up is therefore warranted.

Dual Bracing for Ulnar Collateral Ligament Injuries Restores Native Valgus Laxity and Native Medial Joint Gapping of the Elbow

Background

Despite growing evidence on the role of the posterior ulnar collateral ligament (pUCL) in elbow stability, current ligament bracing techniques are mainly focused on the anterior ulnar collateral ligament (aUCL). A dual-bracing technique combines the repair of the pUCL and aUCL with a suture augmentation of both bundles.

Purpose

To biomechanically assess a dual-bracing approach addressing aUCL and pUCL for humeral-sided complete UCL lesions to restore medial elbow laxity without overconstraining.

Study Design

Controlled laboratory study.

Methods

A total of 21 unpaired human elbows (11 right, 10 left; 57.19 ± 11.7 years) were randomized into 3 groups to compare dual bracing with aUCL suture augmentation and aUCL graft reconstruction. Laxity testing was performed with 25 N applied 12 cm distal to the elbow joint for 30 seconds at randomized flexion angles (0°, 30°, 60°, 90°, and 120°) for the native condition and then for each surgical technique. A calibrated motion capture system was used for assessment, allowing the 3-dimensional displacement during the complete valgus stress cycle between the optical trackers to be quantified as joint gap and laxity. The repaired constructs were then cyclically tested through a materials testing machine starting with 20 N for 200 cycles at a rate of 0.5 Hz. The load was increased stepwise by 10 N for 200 cycles until displacement reached 5.0 mm or complete failure occurred.

Results

Dual bracing and aUCL bracing resulted in significantly (P = .045) less joint gapping at 120° of flexion compared with aUCL reconstruction. No significant differences in valgus laxity were found among the surgical techniques. Within each technique, there were no significant differences between the native and the postoperative state in valgus laxity and joint gapping. No significant differences between the techniques were observed in cycles to failure and failure load.

Conclusion

Dual bracing restored native valgus joint laxity and medial joint gapping without overconstraining and provided similar primary stability regarding failure outcomes as established techniques. Furthermore, it was able to restore joint gapping in 120° of flexion significantly better than aUCL reconstruction.

Clinical Relevance

This study provides biomechanical data on the dual-bracing approach that may help surgeons to consider this new method of addressing acute humeral UCL lesions.

Development and validation of the paediatric elbow trauma (PET) rules as a decision rule for radiography in traumatic elbow injuries: a study protocol

BACKGROUND

Traumatic elbow injuries in children occur frequently and are among the most common traumatic injuries seen in the emergency department (ED) and in general practice. The use of a validated decision rule to enhance selective radiography in paediatric patients with possible elbow fractures may reduce unnecessary exposure to radiation in children.

METHOD AND ANALYSIS

This study is designed as a multicentre prospective cohort study. An expert panel of orthopaedic elbow surgeons, paediatric orthopaedic surgeons and trauma surgeons will initially determine clinical parameters that provide a possible predictive value for elbow fractures. Four hundred children between the ages of 2 and 17 years visiting the ED with pain following elbow trauma will then be included. The clinical parameters will be collected via patient history and physical examination. Elbow radiographs will be obtained in all patients to identify fractures. The data will be processed in a multivariable logistic regression analysis to determine which clinical parameters predict the presence of an elbow fracture. Only the clinical parameters that predict a fracture will be used to formulate the new decision rule: the paediatric elbow trauma (PET) rules. Internal validation of the prediction model will take place after inclusion is complete and by means of a bootstrap analysis on the acquired data. A calculation will be made to determine how many radiographs can potentially be reduced by applying the PET rules and a cost analysis will be performed.

ETHICS AND DISSEMINATION

The study will be conducted according to the principles of the Declaration of Helsinki and in accordance with the Medical Research Involving Human Subjects Act. The Medical Research Ethics Committees United stated on 16 May 2022 that The Medical Research Involving Human Act (WMO) does not apply to this study and an official approval by the committee is not required, reference number; project W22.086.

Radial head replacement - A comprehensive review

Background

Radial head fractures represent 1-4% of all adult fractures and 1/3rd of elbow fractures (Kaas et al., 2010). Radial head is an important secondary stabilier of the elbow. The aim of the treatment of radial head fractures is to achieve stability and good functional outcome. Radial head replacement (RHR) is indicated when robust reconstruction and fixation of the fracture fragments is not possible.

Methods

This article explores history and evolution, anatomical considerations, biomechanics, implant designs, indications, surgical outcomes and controversies in radial head replacement based on current evidence.

Results

There is a wide range of RHR designs available without conclusive evidence to support the superiority of one design over the other. Ranges of motion, functional outcomes and complication were comparable among different designs with a high incidence of complications reported in many studies.

Conclusion

RHR remains a good option in unreconstructible radial head fractures, with potential to regain excellent function. It is imperative to continue with the quest to innovate and improve on current designs, to reduce complications in the long term.

Radiocapitellar Arthroplasty: Systematic Review

Introduction

Primary elbow osteoarthritis affects approximately 2% of the population, and has been treated with arthroplasty. However, total elbow arthroplasty (TEA) implants currently have severe weight limitations and issues with longevity. In patients with unicompartmental arthritis, unicompartmental arthroplasty may be used instead of TEA. We describe the use of Uni-Elbow Radio-Capitellum and Lateral Resurfacing Elbow for radiocapitellar arthroplasty (RCA) in this article.

Methods

Reviewers independently searched databases for keywords, such as radiocapitellar arthroplasty, RCA, uni-elbow radiocapitellum, UNI-E, and lateral resurfacing elbow, LRE. The measured outcomes of interest were the change in motion arc and patient-reported outcome scores. Studies that were not of appropriate quality determined by the Cochrane risk of bias summary tool and review studies were excluded.

Results

RCA resulted in a postoperative 38.3° ± 28.5° increase in elbow flexion-extension (P < .001), and 35.2° ± 28.6° increase in elbow pronation-supination (P < .001). Mayo Elbow Performance Score was significantly increased by 44.8 ± 12.6. DASH Score saw a significant reduction by 45.0 ± 14.6 points (P < .001), while the American Shoulder and Elbow Surgeons Score increased by 47.0 ± 10.6 points (P < .001). Of the 105 adult patients 16.2% experienced complications such as minor stiffness, ulnar neuropathy, component loosening, or radial head UNI-E stem failure. Reported complications were higher in the UNI-E group than in the LRE group.

Conclusion

RCA has shown promise as an option to treat radiocapitellar arthritis, particularly when excising the radial head causes lateral column instability.

Change in humeral anchor position significantly affects isometry in ulnar collateral ligament repair: a 3-dimensional computer modeling study

BACKGROUND

Medial ulnar collateral ligament (UCL) repair utilization is increasing in recent years, bolstered by shorter rehabilitation and satisfactory clinical outcomes. Although previous literature has illustrated the importance of tunnel position on restoring graft isometry in reconstruction, there remains a paucity of literature guiding anchor placement in UCL repair. The purpose of this study is to design a 3-dimensional (3D) elbow model to understand the effect of anchor location on UCL repair isometry.

METHODS

A 3D computer model of an elbow joint was created using computed tomographic and magnetic resonance imaging MRI scans from a single patient. The humeral and ulnar attachments of the UCL were plotted using 3 methodologies: (1) geometric cloud mapping and (2) quantitative measurements from the anatomic studies by Camp et al and (3) Frangiamore et al. A 3.5-mm-diameter clockface was placed on each attachment site, which allowed for simulation of 12 distinct 1.75-mm deviations in anchor position. The 3 models were ranged through 0°-120° at 10° increments, and the 3D distances were measured between the ligament centroids. The humeral and ulnar anchors were sequentially repositioned around the clockfaces, and construct lengths were again measured to evaluate changes in isometry. A paired Student t test was performed to determine if there was a significant difference in isometry between the humeral and ulnar anchor deviations.

RESULTS

Using method 1, the UCL repair length at 90° of elbow flexion was 26.8 mm. This construct underwent 13.6 mm of total excursion for a 46.4% change in length throughout its arc of motion. Method 2 produced a 19.3-mm construct that underwent 0.8 mm of excursion for a 3.9% length change throughout the arc. Method 3 produced a 24.5-mm construct that underwent 2.3 mm of excursion for a 9.4% length change. Identifying ligament footprints using the quantitative anatomic measurements from Camp et al and Frangiamore et al improved construct isometry through 120° of flexion (length changes of 3.9% and 9.4%, respectively) when compared to using the geometric cloud technique alone (46.4% length change). Humeral anchor deviations produced a significant increase in repair construct excursion compared with ulnar anchor deviations (P < .001).

CONCLUSION

When performing UCL repair, small deviations in humeral anchor position may significantly influence ligament repair isometry. Using quantitative anatomic data may help identify anchor positions with improved repair isometry. Particularly when addressing detachments of the humeral footprint, surgeons should be critical of the humeral anchor position in order to restore native anatomy and optimal biomechanics.

Osseous variability around the elbow joint

There are many osseous variants that occur around the elbow joint such as supracondylar process, supratrochlear foramen, accessory ossicles, and others. Scientific databases were searched for variants around the elbow joint. Elbow radiographs from our center demonstrating some of these findings were included in the study. The aim of the present review was to provide comprehensive information on the terminology, prevalence, history, etiology, and clinical importance of these variants. These anatomical variants are important for radiologists while interpreting radiographs, computed tomography, and magnetic resonance imaging for trauma and orthopedic surgeons during osteosynthesis at the distal humerus, proximal ulna, and radius.

Immunofluorescence analysis of sensory nerve endings in the periarticular tissue of the human elbow joint

INTRODUCTION

To investigate the dynamic aspects of elbow stability, we aimed to analyze sensory nerve endings in the ligaments and the capsule of elbow joints.

MATERIALS AND METHODS

The capsule with its anterior (AJC) and posterior (PJC) parts, the radial collateral ligament (RCL), the annular ligament (AL), and the ulnar collateral ligament with its posterior (PUCL), transverse (TUCL) and anterior parts (AUCL) were dissected from eleven human cadaver elbow joints. Sensory nerve endings were analyzed in two levels per specimen as total cell amount/ cm² after immunofluorescence staining with low-affinity neurotrophin receptor p75, protein gene product 9.5, S-100 protein and 4',6-Diamidin-2-phenylindol, Carbonic anhydrase II and choline acetyltransferase on an Apotome microscope according to Freeman and Wyke's classification.

RESULTS

Free nerve endings were the predominant mechanoreceptor in all seven structures followed by Ruffini, unclassifiable, Golgi-like, and Pacini corpuscles (p ≤ 0.00001, respectively). Free nerve endings were observed significant more often in the AJC than in the RCL (p < 0.00002). A higher density of Ruffini endings than Golgi-like endings was observed in the PJC (p = 0.004). The RCL contained significant more Ruffini endings than Pacini corpuscles (p = 0.004). Carbonic anhydrase II was significantly more frequently positively immunoreactive than choline acetyltransferase in all sensory nerve endings (p < 0.05). Sensory nerve endings were significant more often epifascicular distributed in all structures (p < 0.006, respectively) except for the AJC, which had a pronounced equal distribution (p < 0.00005).

CONCLUSION

The high density of free nerve endings in the joint capsule indicates that it has pronounced nociceptive functions. Joint position sense is mainly detected by the RCL, AUCL, PUCL, and the PJC. Proprioceptive control of the elbow joint is mainly monitored by the joint capsule and the UCL, respectively. However, the extreme range of motion is primarily controlled by the RCL mediated by Golgi-like endings.

Regional differences in the three-dimensional bone microstructure of the radial head: implications for observed fracture patterns

INTRODUCTION

A characterization of the internal bone microstructure of the radial head could provide a better understanding of commonly occurring fracture patterns frequently involving the (antero)lateral quadrant, for which a clear explanation is still lacking. The aim of this study is to describe the radial head bone microstructure using micro-computed tomography (micro-CT) and to relate it to gross morphology, function and possible fracture patterns.

MATERIALS AND METHODS

Dry cadaveric human radii were scanned by micro-CT (17 μm/pixel, isotropic). The trabecular bone microstructure was quantified on axial image stacks in four quadrants: the anterolateral (AL), posterolateral (PL), posteromedial (PM) and anteromedial (AM) quadrant.

RESULTS

The AL and PL quadrants displayed the significantly lowest bone volume fraction and trabecular number (BV/TV range 12.3-25.1%, Tb.N range 0.73-1.16 mm^-1) and highest trabecular separation (Tb.Sp range 0.59-0.82 mm), compared to the PM and AM quadrants (BV/TV range 19.9-36.9%, Tb.N range 0.96-1.61 mm^-1, Tb.Sp range 0.45-0.74 mm) (p = 0.03).

CONCLUSIONS

Our microstructural results suggest that the lateral side is the "weaker side", exhibiting lower bone volume faction, less trabeculae and higher trabecular separation, compared to the medial side. As the forearm is pronated during most falls, the underlying bone microstructure could explain commonly observed fracture patterns of the radial head, particularly more often involving the AL quadrant. If screw fixation in radial head fractures is considered, surgeons should take advantage of the "stronger" bone microstructure of the medial side of the radial head, should the fracture line allow this.

Elbow Dislocations in the National Football League: Epidemiology and Management

Background Currently, it is not known how the combined osseous and ligamentous injury of a traumatic elbow dislocation in a National Football League (NFL) athlete affects management and return to play. In this study, we aimed to describe the epidemiology, management, and return to play for elbow dislocations in NFL athletes. Methodology This is a descriptive observational study. A retrospective review of all elbow dislocations between 2000 and 2014 (15 seasons) was performed using the NFL Injury Surveillance System (NFLISS). Results Over 15 NFL seasons, 82 elbow dislocations were recorded in the NFLISS. Among players who reported surgery (n = 5), players missed an average of 73.8 days of play. Among those who did not report surgery, players missed an average of 36.1 days. The overall incidence was 0.26 dislocation events per 10,000 athlete exposures. The majority of these injuries occurred during regular-season games, in defensive linebackers and linemen, during tackling contact with another player, and most commonly on a running play. Conclusions This study demonstrates that an elbow dislocation is not a career-ending or season-ending injury in an NFL cohort. Information regarding incidence, positions affected, whether surgical management is utilized, and return to play will help players who sustain and physicians who treat these injuries in elite football athletes understand the impact of their injuries.

Cemented radial head arthroplasty: Does radiographic loosening have an effect on clinical and functional outcomes? Average 10 years' results

PURPOSE

The aim of this study was to evaluate the possible effect of radiographic loosening on clinical and functional outcomes, while presenting the mid-term radiographic and functional outcomes of cemented, monopolar RHA applied to patients with comminuted radial head fractures.

METHODS

We performed a retrospective study by evaluating the records of patients who were diagnosed in a single center with radial head fractures between 2001 and 2013. Twenty-six patients with comminuted radial head fractures with a mean age of 48.9 and a mean follow-up time of 132.2 months were included. The radiographic evaluation was performed by assessing peri-prosthetic radiolucent lines around the stem to evaluate loosening, while the clinical evaluation was performed by utilizing elbow range of motion (ROM), Mayo elbow performance score (MEPS), Oxford elbow score (OES) and quick-DASH scores.

RESULTS

13 patients (Group 1) with peri-prosthetic stem lucency were defined as radiographic loosening (50%), while the remaining 13 patients (Group 2) were not detected to have stem lucency. One patient in group 1 also had concomitant pain and underwent removal of the prosthesis, while 12 patients (92.3%) remained pain-free. On the latest follow-up visit, there was no significant difference between the groups regarding ROM, MEPS, OES and quick-DASH scores.

CONCLUSIONS

Within ten years following surgery, half of the patients with radial head prostheses were noted to show radiographic signs of loosening which did not have any major negative effect in terms of clinical-functional outcomes and quality of life, except requiring the removal of the implant in one patient.

LEVEL OF EVIDENCE

Level III.

Imaging of Elbow Injuries

Familiarity with throwing mechanics during elbow range of motion allows accurate diagnosis of sports-related elbow injuries, which occur in predictable patterns. In addition, repetitive stress-related injuries are often clinically apparent; however, imaging plays an important role in determining severity as well as associated injuries that may affect clinical management. A detailed understanding of elbow imaging regarding anatomy and mechanism of injury results in prompt and precise treatment.

Increased volume and collagen crosslinks drive soft tissue contribution to post-traumatic elbow contracture in an animal model

Post-traumatic joint contracture (PTJC) in the elbow is a biological problem with functional consequences. Restoring elbow motion after injury is a complex challenge because contracture is a multi-tissue pathology. We previously developed an animal model of elbow PTJC using Long-Evans rats and showed that the capsule and ligaments/cartilage were the primary soft tissues that caused persistent joint motion loss. The objective of this study was to evaluate tissue-specific changes within the anterior capsule and lateral collateral ligament (LCL) that led to their contribution to elbow contracture. In our rat model of elbow PTJC, a unilateral surgery replicated damage that commonly occurs due to elbow dislocation. Following surgery, the injured limb was immobilized for 42 days. The capsule and LCL were evaluated after 42 days of immobilization or 42 days of immobilization followed by 42 days of free mobilization. We evaluated extracellular matrix protein biochemistry, non-enzymatic collagen crosslink content, tissue volume with contrast-enhanced micro-computed tomography, and tissue mechanical properties. Increased collagen content, but not collagen density, was observed in both injured limb capsules and LCLs, which was consistent with the increased tissue volume. Injured limb LCLs exhibited decreased normalized maximum force, and both tissues had increased immature collagen cross-links compared to control. Overall, increased tissue volume and immature collagen crosslinks in the capsule and LCL drive their contribution to elbow contracture in our rat model.

Is there a role for elbow arthrodesis in 21st Century - Current concepts and overview of surgical techniques

Elbow arthrodesis is uncommon and is usually performed as a salvage procedure to provide a stable elbow. There is a significant gap in the literature about the indications, contraindications, fusion angle, technical tips, and reversibility of the procedure. This review addresses these questions in a evidence based manner, based on the published literature.

Radiographic and MRI Assessment of the Thrower's Elbow

PURPOSE OF REVIEW

Throwing athletes are vulnerable to elbow injuries, especially in the medial elbow, related to high stress and valgus load in both acute and chronic settings as a result of this complex biomechanical action. This current review details the relevant anatomy and imaging features of common elbow pathology identified with radiographs and MRI in throwing athletes.

RECENT FINDINGS

Although elbow pathology in throwing athletes is well documented, advances in imaging technology and technique, particularly with MRI, have allowed for more detailed and accurate imaging description and diagnosis. Pathology of thrower's elbow occurs in predictable patterns and can be reliably identified radiologically. Clinical history and physical examination should guide radiologic evaluation initially with radiographs and followed by an MRI optimized to the clinical question. Constellation of clinical, physical, and radiologic assessments should be used to guide management.

Long-term outcomes after different types of Horne and Tanzer olecranon fractures

BACKGROUND

It is unclear whether the outcomes differ after different Horne and Tanzer types of olecranon fractures.

MATERIALS AND METHODS

We evaluated 40 men and 55 women with isolated olecranon fractures, journals and radiographs from fracture event. The fractures were classified according to Horne and Tanzer. After a mean 19 years after the fracture events, we evaluated subjective, clinical and radiographic outcomes, using the uninjured arms as controls.

RESULTS

95% of patients with type I fractures reported, at follow-up, no differences between the elbows, 80% with type II fractures and 95% with type III fractures (p = 0.43). The three types of fractures had no differences in elbow range of motion or hand grip strength (when comparing injured and uninjured arms) and the proportions of individuals with radiographic elbow degenerative changes or joint space reduction were no different (all p > 0.05). Individuals with elbow degenerative changes had no inferior subjective elbow function compared to individuals with normal radiographs (p = 0.66), in contrast to those with joint space reduction compared to individuals with normal radiographs (p < 0.001).

INTERPRETATION

All types of Horne and Tanzer olecranon fractures have favourable long-term outcome. Elbow joint space reduction is associated with inferior subjective elbow function while degenerative changes are not.

Finite Element Analysis of Insertion Angle of Absorbable Screws for the Fixation of Radial Head Fractures

Objective

To investigate the biomechanical effects of different insertion angles of absorbable screws for the fixation of radial head fractures.

Methods

The finite element models used to simulate the fractures were created based on CT scans. Two absorbable screws were used to fix and maintain the stability of the fracture, and the angles between the screws were set to 0°, 15°, 30°, 45°, 60°, 75°, and 90°. A downward force of 100 N was applied at the stress point, which was coupled with the surface, and the distal radius was limited to six degrees of freedom. The direction and location of the applied force were the same in each model. The values of the von Mises stress and peak displacements were calculated.

Results

Under the applied load and different screw angles, the maximum von Mises stress in the screws was concentrated on the surface contacting the fracture surfaces. The maximum von Mises equivalent stress in the screw decreased when the angle increased from 0° (19.54 MPa) to 45° (13.11 MPa) and increased when the angle further increased to 90° (24.63 MPa). The peak displacement decreased as the angle increased from 0° (0.19 mm) to 45° (0.15 mm) and increased when the angle further increased to 90° (0.25 mm).

Conclusion

The computational stress distribution showed that fixation with absorbable screws is safe for patients. Moreover, the minimum von Mises stress and displacements were generated when the angle between the screws was 45°; hence, this setting should be recommended for Mason type II radial fractures.

Effect of elbow MRI with axial traction on articular cartilage visibility-a feasibility study

OBJECTIVE

Accurate evaluation of the articular cartilage of the elbow using MRI is sometimes challenging because of its anatomical complexity and relatively small size. Moreover, the articular cartilage of the humerus is in close contact with the opposing cartilage surfaces. Magnetic resonance arthrography with traction was reported to resolve this issue; however, less invasive methods are desirable. This study aimed to assess the effect of MRI with axial traction (without arthrography) on joint space widening and cartilage outline visibility of the elbow.

MATERIALS AND METHODS

We enrolled 10 volunteers (female = 1; mean age, 36.7 ± 8.6; range 28-56) and performed MRI with and without axial traction on the elbow. Joint space widths were measured, and the humeral articular cartilage outline visibility was evaluated at the radiocapitellar joint and lateral one-third and medial one-third of the ulnohumeral joints. Measurements were compared using the Wilcoxon signed-rank test. Significance was set at p < 0.05. Volunteers scored pain and discomfort during MRI with traction using the visual analog scale in a questionnaire format.

RESULTS

Traction significantly increased joint space width at the radiocapitellar joint. Humeral articular cartilage outline visibility also significantly improved at the radiocapitellar joint. Pain and discomfort scores during traction MRI were low.

CONCLUSION

MRI of the elbow with traction widens joint space and enables better articular cartilage visibility at the radiocapitellar joint. Anatomical features of the elbow might have affected these results. Therefore, it would be safe and useful for evaluating elbow injuries involving articular cartilage lesions.

Augmented intramedullary screw tension band construct for olecranon fracture reduction and fixation: a review of literature and surgical technique

Olecranon fractures, which make up 10% of upper extremity fractures in adults, often require anatomic reduction and stable internal fixation. Successful olecranon fracture osteosynthesis has classically been achieved via tension band wiring or plate fixation. This article reviews the indications, outcomes, and a surgical technique as an alternative construct for tension band wiring of olecranon fractures. The technique involves placement of an ulnar intramedullary partially threaded screw that is used as a proximal point of attachment for tension band wiring of the olecranon. Although infrequently used by orthopedic surgeons, this construct has been shown to be biomechanically and clinically superior to classic Kirschner wire tension banding techniques. This review is intended to familiarize surgeons with a surgical technique that can be applied to a variety of proximal ulna fractures.

Modified Lateral Approach of the Elbow for Surgical Release and Synovectomy

Elbow stiffness is a common reason for consultation. In recent years, arthroscopic techniques in elbow surgery have progressed, but there are still some contraindications to performance of arthroscopic synovectomy and release in this joint (elbows with anatomic deformity after multiple procedures, malunion, presence of osteosynthesis material, severe stiffness of >80 degrees, instability, or previous transposition of the ulnar nerve). Therefore, knowledge of a safe and reliable open approach to achieve elbow release and/or synovectomy is essential. We report the technical details of the modified lateral approach between extensor carpi radialis brevis and longus muscles, as well as the clinical results of 43 elbow release and/or synovectomy procedures, illustrating its feasibility. The modified lateral approach, providing visual control of the radial nerve and good anterior exposure of the elbow joint, is detailed. From 1994 to 2016, this approach was used in 43 release and/or synovectomy procedures of the elbow in 41 patients, 30 men and 11 women, with a mean age of 40.56 years (range, 17 to 84 y). Using this procedure, 38 elbows (93%) recovered full extension and 5 subtotal extension with an average deficit of 11 degrees (range, 5 to 20 degrees). All elbows were stable. No neurological complications were reported. The modified lateral approach preserves the insertion of the lateral epicondyle muscles that are major dynamic stabilizers and reduces the risk of instability. Initially described for the treatment of radial tunnel syndrome, it should also be recommended for elbow release and synovectomy.

State of the Union on Ulnar Collateral Ligament Reconstruction in 2020: Indications, Techniques, and Outcomes

PURPOSE OF REVIEW

There has been a marked increase in the number of ulnar collateral ligament reconstructions performed annually and an associated increase in the amount of recent literature published. It is paramount that surgeons remain up to date on the current literature, as modern indications and surgical techniques continue to improve clinical outcomes.

RECENT FINDINGS

Our understanding of ulnar collateral ligament (UCL) injuries, treatment indications, and surgical techniques for UCL reconstruction continues to evolve. Despite the rapidly increasing amount of published literature on the topic, a clear and concise surgical algorithm is lacking. Studies have suggested a trend towards improved clinical outcomes and decreased complications with various modifications in UCL reconstruction techniques. Current sport-specific outcome studies have reported conflicting results regarding the effect of UCL reconstruction on an athlete's performance upon returning to sport. With the rising incidence of UCL reconstruction and growing media attention, UCL injuries, reconstruction techniques, and return to sport following UCL surgery are timely topics of interest to clinicians and overhead throwing athletes. Several technique modifications have been reported, and these modifications may lead to improved outcomes and lower complication rates. Studies assessing sport-specific outcome measures will be necessary to provide a more critical and informative analysis of outcomes following UCL reconstruction.

Review of Anatomy of the Medial Ulnar Collateral Ligament Complex of the Elbow

PURPOSE OF REVIEW

The importance of both the static and dynamic stabilizers of the medial elbow for the throwing athlete has been demonstrated in recent studies. Furthermore, recent anatomic studies have demonstrated the insertion of the anterior bundle (UCL) to be more distal and elongated, which has implications for surgical reconstruction of the UCL. The purpose of this review is to highlight recent anatomic and biomechanical studies evaluating the anatomy and reconstructions of the medial elbow.

RECENT FINDINGS

Recent literature has highlighted the crucial role of the dynamic stabilizers in resisting valgus force, especially during the throwing motion. The dynamic stabilizers of the medial elbow include the flexor pronator mass, specifically the flexor carpi ulnaris (FCU) and flexor digitorum superficialis (FDS). The clinical importance of these findings cannot be under stated, as unrecognized dynamic stabilizer injury can lead to increased stress on a native or reconstructed UCL in the throwing athlete. The medial ulnar collateral ligament complex of the elbow has a crucial role in providing both static and dynamic elbow stability. Most notably, the anterior bundle (UCL) provides the primary resistance to valgus and rotational stresses, especially during throwing motion. An understanding of the humeral and ulnar footprints and their relationships with surrounding structures is necessary to restore the native isometry of the medial complex of the elbow during UCL reconstruction. The flexor pronator musculature plays an essential role in dynamic stability, and the intimate relationship of the FCU and FDS with the ulnar insertion of the UCL should be considered to optimize recovery and outcomes with repair or reconstruction.

Hysteresis and Synergy of the Central Commands to Muscles Participating in Parafrontal Upper Limb Movements

The averaged electromyograms (EMGs) were registered from the arm muscles of ten subjects in movements of the right hand performed under visual guidance on the horizontal plane along linear trajectories going parallel to the frontal plane at various distances from the trunk. The tests consisted of the steady movements (speed 4 cm/s) between two points symmetrical about the shoulder axis; the hand moved firstly from left to right, then in the opposite direction. The tests repeated ten times for each of two equal loads (10.2 N) applied to the hand along movement trajectory in the right- (F_r) or leftward (F_l) directions. The elbow and shoulder flexors reacted predominantly on F_r loads; the extensors were mostly activated by F_l loads. Positional changes of the averaged EMGs in both flexor and extensor muscles belonging to different joints demonstrated hysteresis properties; the respective hysteresis loops had counterclockwise direction in flexors and clockwise in extensors. The muscles predominantly opposing the loading forces of a given direction participate in a cocontraction mode as antagonists when the direction of load is changed; in this case, together with a decrease in the amplitude of the hysteresis loops, their direction is also reversed. The multiplication index of synergy (MIS), which is based on multiplication of the respective normalized averaged EMG records, has been proposed to evaluate quantitatively changes in the synergy effects between various muscle groups. For distal shifts of the movement traces, the synergy effects are shown to be changed in different directions, increasing in flexors and decreasing in extensors. The obtained results demonstrate that the muscle hysteresis leads to strong modification of the central commands during movements.

Long-Term Outcomes after Colton Type I and II Fractures of the Olecranon

Background:

It is unclear if the outcomes differ in different subtypes of olecranon fractures.

Objective:

Evaluate the outcomes of different Colton types of olecranon fractures, and if outcomes differ in dominant and non-dominant arms and in men and women.

Methods:

We evaluated primary journals and radiographs in 40 men and 55 women with isolated olecranon fractures and classified fractures according to Colton. Mean 19 years after fracture event, we re-examined subjective, clinical and radiographic outcomes in the former patients, using the uninjured arms as controls.

Results:

89% of patients with Colton type I fractures reported at follow-up no subjective differences between the elbows, 84% with type II oblique/transverse fractures and 84% with type II comminuted fractures (p=0.91). The uninjured to former fractured arm differences in elbow range of motion and strength were no different in the 3 fracture types, the proportions of individuals with radiographic elbow degenerative changes were greater in type II than in type I factures (p<0.001), and there were no differences between the proportions of individuals with reduced joint space in the 3 groups (p=0.40). The outcomes were no different if the fractures had occurred in the dominant or non-dominant arms (p=0.43), or in men or women (p=0.43).

Conclusion:

There were no different outcomes after Colton type I, type II oblique/transverse or type II comminuted fractures, no different outcomes between fractures in dominant or non-dominant arms and no different outcomes in men and women.

Biomechanical Role and Motion Contribution of Ligaments and Bony Constraints in the Elbow Stability: A Preliminary Study

In flexion–extension motion, the interaction of several ligaments and bones characterizes the elbow joint stability. The aim of this preliminary study was to quantify the relative motion of the ulna with respect to the humerus in two human upper limbs specimens and to investigate the constraints role for maintaining the elbow joint stability in different section conditions. Two clusters of four markers were fixed respectively to the ulna and humerus, and their trajectory was recorded by a motion capture system during functional orthopedic maneuver. Considering the posterior bundle of medial collateral complex (pMUCL) and the coronoid, two section sequences were executed. The orthopedic maneuver of compression, pronation and varus force was repeated at 30°, 60° and 90° flexion for the functional investigation of constraints. Ulna deflection was compared to a baseline elbow flexion condition. With respect to the intact elbow, the coronoid osteotomy influences the elbow stability at 90° (deflection = 11.49 ± 17.39 mm), while small differences occur at 30° and 60°, due to ligaments constraint. The contemporary pMUCL section and coronoid osteotomy causes elbow instability, with large deflection at 30° (deflection = 34.40 ± 9.10 mm), 60° (deflection = 45.41 ± 18.47 mm) and 90° (deflection = 52.16 ± 21.92 mm). Surgeons may consider the pMUCL reconstruction in case of unfixable coronoid fracture.

Functional and Surgical Anatomy of the Upper Limb: What the Radiologist Needs to Know

The anatomy of the upper limb is complex and allows for exceptional functionality. The movements of the joints of the shoulder, elbow, and wrist represent a complex dynamic interaction of muscles, ligaments, and bony articulations. A solid understanding and of the characteristics and reciprocal actions of the anatomic elements of the joints of the upper limb helps explain the mechanisms and patterns of injury. This article focuses on the anatomy and functionality of the shoulder, elbow, and wrist, with emphasis on the stabilizing mechanisms, to set the foundation for understanding the occurrence of pathologic conditions.

Three-dimensional computed tomography modeling for kinematic analysis of double-strand lateral ulnar collateral ligament reconstruction

BACKGROUND

When treating posterolateral rotatory instability, the lateral ulnar collateral ligament (LUCL) is more commonly reconstructed than the other dynamic stabilizer structures. Although numerous surgical techniques have been described for LUCL reconstruction, studies have been limited to static analyses of single-strand reconstructions. The aim of this study was to dynamically analyze the kinematics of double-strand LUCL reconstructions with 3 different configurations of graft placement: horizontal, vertical, and triangular.

METHODS

Five healthy elbow joints with no signs of pre-existing pathology were scanned by computed tomography, and the images were converted into 3-dimensional models. The humeral origin and ulnar insertions of the 2 ligament strands were registered in 3-matic software for the 3 graft placement configurations. A dynamic elbow joint was simulated at 1° increments throughout the motion arc. The ligament strand lengths and the difference between them were measured.

RESULTS

The ligament lengths for each strand for the 3 graft configurations were as follows: horizontal, 31.0 ± 4.6 mm and 34.3 ± 5.0 mm; vertical, 32.5 ± 3.6 mm and 35.4 ± 4.2 mm; and triangular, 32.0 ± 4.0 mm and 33.7 ± 3.1 mm. The minimum length differences for the graft strands through the motion arc for the horizontal, vertical, and triangular graft configurations were 1.1, 0.0, and 1.0 mm, respectively.

CONCLUSIONS

Dynamic analyses using a 3-dimensional elbow model showed that none of the configurations for double-strand LUCL reconstruction were isometric. However, the vertical double-strand configuration was nearly isometric and may therefore serve as a coequal option.

Role of the anconeus in the stability of a lateral ligament and common extensor origin-deficient elbow: an in vitro biomechanical study

BACKGROUND

The role of the anconeus in elbow stability has been a long-standing debate. Anatomic and electromyographic studies have suggested a potential role as a stabilizer. However, to our knowledge, no clinical or biomechanical studies have investigated its role in improving the stability of a combined lateral collateral ligament and common extensor origin (LCL + CEO)-deficient elbow.

METHODS

Seven cadaveric upper extremities were mounted in an elbow motion simulator in the varus position. An injured model was created by sectioning of the CEO and the LCL. The anconeus tendon and its aponeurosis were sutured in a Krackow fashion and tensioned to 10 N and 20 N using a transosseous tunnel. Varus-valgus angles and ulnohumeral rotations were recorded using an electromagnetic tracking system during simulated active elbow flexion with the forearm pronated and supinated.

RESULTS

During active motion, the injured model resulted in a significant increase in varus angulation (P = .0001 for pronation; P = .001 for supination) and external rotation (P = .001 for pronation; P = .003 for supination) of the ulnohumeral articulation compared with the intact state. Tensioning of the anconeus significantly decreased the varus angulation (P = .006 for 10 N pronation; P = .0001 for 20 N pronation; P = .0001 for 10 N supination; P = .0001 for 20 N supination) and external rotation angle (P = .008 for 10 N pronation; P = .0001 for 20 N pronation; P = .0001 for 10 N supination; P = .0001 for 20 N supination) of the injured elbow.

CONCLUSIONS

In the highly unstable varus elbow orientation, anconeus tensioning restores the in vitro stability of a combined LCL + CEO-deficient elbow during simulated active motion with the forearm in both pronation and supination. These results may have several clinical implications in managing symptomatic lateral elbow instability.

Maximizing outcomes in the treatment of radial head fractures

The radial head plays a critical role in the stability of the elbow joint and its range of motion. Injuries may occur across a spectrum of severity, ranging from low energy non-displaced fractures to high energy comminuted fractures. Multiple classification systems exist to help characterize radial head fractures and their associated injuries, as well as to guide treatment strategies. Depending on the type of fracture, non-operative management may be possible if early range of motion is initiated. Other options include open reduction and internal fixation or excision followed by arthroplasty. A lateral approach is typically used for adequate surgical exposure. Controversy still remains regarding operative management of more severe fractures, but studies have shown good outcomes after radial head replacement for these fractures. We will review the current treatments available for radial head fractures, highlighting gaps in knowledge, as well as providing recommendations for the care of these injuries.

Level of evidence: Level V.