Novel Radiographic Indexes for Elbow Stability Assessment: Part A-Cadaveric Validation

Increasing Severity of Radial Longitudinal Deficiency Correlates With the Degree of Proximal Ulnar Hypoplasia

PURPOSE

Classification systems and treatment for children with radial longitudinal deficiency are classically focused on the hand and wrist. However, the elbow can affect the function of these patients secondary to stiffness or instability. The objective of this study was to determine if a correlation exists between severity of radial longitudinal deficiency (RLD) and degree of proximal ulnar hypoplasia.

METHODS

A single-institution retrospective review was performed at a pediatric hospital. One hundred elbows were identified in 72 patients who met the inclusion criteria. Measurements such as the coronoid height, olecranon coronoid angle (OCA), and the anterior coverage index were obtained from lateral radiographs of children with RLD. Ten elbows had posterior subluxation of the ulnohumeral joint radiographically. Eleven patients had thrombocytopenia absent radius (TAR) syndrome.

RESULTS

There was a significant mean difference for OCA between RLD types. Type 4 RLD (mean [M] = 17.9; standard deviation [SD] = 11.3) had a significantly lower OCA than type 0 (M = 26.4; SD = 5.9) and type 1 (M = 31.0; SD = 5.0). A subanalysis of the 58 elbows with type 4 RLD demonstrated that those with TAR (n = 11) had significantly higher anterior coverage index total scores (M = 1.7; SD = 0.3) than those with type 4 without TAR (M = 1.5; SD = 0.2).

CONCLUSIONS

The degree of proximal ulnar hypoplasia is correlated with increasing severity of RLD, with significantly lower OCA and coronoid height observed in the elbow radiographs of patients with type 4 RLD compared with type 0 and type 1. Children with TAR have less proximal ulnar dysplasia and higher anterior coverage index than children with type 4 RLD without associated TAR.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic IV.

Considerable variation in current coronoid height and fracture measurement techniques: a systematic review

BACKGROUND

Coronoid fractures usually occur in the presence of a significant osseoligamentous injury to the elbow. Fracture size and location correlate with degree of instability and many authors have attempted to analyze the effect of fracture variation on decision making and outcome. There remains no standardized technique for measuring coronoid height or fracture size. The aim of this study was to appraise the literature regarding techniques for coronoid height measurement in order to understand variation.

METHODS

Preferred Reporting Items of Systematic Reviews and Meta-Analyses guidelines were followed. A search was performed to identify studies with either a description of coronoid height, fracture size, or bone loss using the terms (Coronoid) AND (Measurement) OR (Size) OR (Height). Articles were shortlisted by screening for topic relevance based on title, abstract and, if required, full-text review. Exclusion criteria were non-English articles, those on nonhuman species or parts other than the ulna coronoid process, and studies that included patients with pre-existing elbow pathology. Shortlisted articles were grouped based on study type, imaging modality, measurement technique, and measurement parameter as well as its location along the coronoid.

RESULTS

Thirty out of the initially identified 494 articles met the inclusion criteria. Twenty-one articles were clinical studies, 8 were cadaveric studies, and 1 combined patients as well as cadavers. A variety of imaging modalities (plain radiographs, 2-dimensional computed tomography [CT], 3-dimensional CT, magnetic resonance imaging or a combination of these) were used with CT scan (either 2-dimensional images or 3-dimensional reconstructions or both) being the most common modality used by 21 studies. Measurement technique also varied from uniplanar linear measurements in 15 studies to multiplanar area and volumetric measurements in 6 studies to techniques describing various angles and indices as an indirect measure of coronoid height in 8 studies. Across the 30 shortlisted studies, 19 different measurement techniques were identified. Fifteen studies measured normal coronoid height while the other 15 measured intact coronoid and/or fracture fragment height. The location of this measurement was also variable between studies with measurements at the apex of the coronoid in 24/30 (80%) of studies. Measurement accuracy was assessed by only 1 study. A total of 12/30 (40%) studies reported on the interobserver and intraobserver reliability of their measurement technique.

CONCLUSION

The systemic review demonstrated considerable variability between studies that report coronoid height or fracture size measurements. This variability makes comparison of coronoid height or fracture measurements and recommendations based on these between studies unreliable. There is need for development of a consistent, easy to use, and reproducible technique for coronoid height and bone loss.

A 70° Arthroscope Provides Better Visualization of the Medial Side of the Elbow Than a 30° Arthroscope

Purpose

To assess and quantify the improvement in visualization of humeral insertion of the medial collateral ligament (MCL) using a 70° scope compared with a 30° scope during elbow arthroscopy.

Methods

Twenty patients undergoing elbow arthroscopy for different pathologic conditions were enrolled in this single-center study. Visualization of the medial gutter of the elbow was evaluated by using both the 70° and the 30°scope. During the procedure, a needle was inserted at 45° with respect to the axis of the forearm, directed toward the intra-articular humeral emergence of the MCL. Four areas were established: the body (Z1), the lanceolate part (Z2), the tip of the needle (Z3), and the medial portion of the trochlea (Z4). The visible areas during arthroscopy using 2 different scopes were collected.

Results

The 70° scope allowed the detection of the first 3 areas in all patients (Z1, Z2, and Z3) and the visualization of the last area (Z4) in 19 patients (95%). On the other hand, the 30° scope allowed the detection of Z1 in 85% of patients, Z2 in 60% of patients, and Z3 in only 5% of patients. The medial portion of the trochlea was never visualized with the 30° scope. These findings were statistically significant.

Conclusions

The 70° scope improves visualization of the medial elbow compartment during elbow arthroscopy compared to the 30° scope, enhancing the extent of joint visualization and potentially permitting the detection of otherwise missed injuries in the difficult-to-reach areas of the joint.

Level of Evidence

Level II, diagnostic, prospective, cohort study.

Humeral trochlear morphology does not influence coronoid fractures in elbow dislocation

PURPOSE

Traumatic elbow dislocation is the second most frequent joint dislocation, even though the elbow is a congruent and stable joint. Individual variability in anatomical congruence of the elbow and how it relates to simple or complex instability has rarely been studied in the literature; we hypothesized that a greater articular coverage by the humeral trochlea would be more likely to result in complex dislocation. The aim of this study is to analyze trochlear morphology in simple (SED) and complex elbow dislocation (CED), to assess whether the degree of humeroulnar joint congruence influences the incidence of coronoid fractures in elbow dislocation. The secondary goal is to evaluate the association between trochlear morphology and coronoid fracture pattern.

METHODS

All the elbow CT scans of the hospital server were retrospectively analyzed. 62 patients were enrolled and so divided in 2 groups: SED and CED with isolated coronoid fracture. Patients who were skeletally immature, presented with other concomitant elbow fractures, or who previously underwent elbow surgery were excluded. The CT scans were performed after closed reduction and prior to further treatment. Coronoid fracture pattern was classified on CT scan according to Regan-Morrey and O'Driscoll classifications; "grade 0" was assigned to SED. Trochlear coverage was measured and expressed as three angles (anterior, posterior, and distal) and their width/depth ratios. Measurements were taken by four different readers and the assessment was repeated after 15 days.

RESULTS

No statistically significant difference was found between humeral trochlear morphology of SED and CED patients. There was no association between morphometric measurements and coronoid fracture pattern. The results are strengthened by a good intra- and inter-reader reproducibility of the CT analysis protocol.

CONCLUSIONS

Our study is the first to evaluate the impact of trochlear morphology on elbow instability. Considering the results, other variables may have a greater impact on coronoid bone damage, such as trauma energy or ligamentous hyperlaxity: in particular, we believe that the capsuloligamentous structures of the elbow might contribute in a preponderant way to articular stability. The CT analysis protocol gave excellent results: reproducible, accurate and easy to perform.

LEVEL OF EVIDENCE

III.

Morphological and radiological study of the shoulder and elbow joints of the giant anteater (Myrmecophaga tridactyla)

The giant anteater (Myrmecophaga tridactyla) has specialized thoracic limbs to forage by breaking the walls of anthills and termite mounds. They also play critical roles in defense posture and locomotion. This study aimed to provide a morphological and radiographic description of the shoulder joint and elbow joint of the giant anteater. Both joints of 13 tamanduas were assessed by morphological dissections and histological evaluation and radiographies without and with positive contrast. The radiographic projections selected to this study were the mediolateral and craniocaudal projections. The radiographic and anatomical findings were compared with the following results: the shoulder joint had a continuous joint capsule with the tendon sheaths of the short head and long head of the biceps brachii muscle, which could be visualized with an injection of 3 ml of intra-articular contrast. The shoulder joint arthrography was performed with the needle positioned cranially to the joint for contrast injection. The elbow joint presented three articular compartments, and the insertion of the joint capsule was proximal to the radial fossa and distal to the radial tuberosity in the radial notch of the ulna, which were possible to identify with 2 ml of intra-articular contrast. The elbow joint arthrography was performed with the needle positioned laterally to the joint for contrast injection. Moreover, the joint capsule presented a caudomedial distention and fat pads. The powerful muscles of the forelimb play a fundamental role in maintaining the shoulder joint and elbow joint stability due to bony adaptations and the absence of usual ligaments. The morphological and radiological study provided relevant information on the soft-tissue characteristics of shoulder and elbow joints, which may aid clinical-surgical and diagnostic imaging procedures.

Clinical Presentation and Characteristics of the Upper Extremity in Patients with Musculocontractural Ehlers–Danlos Syndrome

Musculocontractural Ehlers–Danlos syndrome (mcEDS) is a subtype of EDS caused by defective dermatan sulfate biosynthesis, characterized by multiple malformations (craniofacial features, ocular and visceral malformations) and progressive cutaneous, skeletal, vascular, and visceral fragility-related manifestations. Repeated dislocations and deformities of the joints due to joint relaxation are observed, causing serious damage to the musculoskeletal system of the whole body; however, the motor function of the upper limbs and the morphology of the bone joints have not been systematically investigated. In this study, we present a detailed and comprehensive report on upper limb lesions of 13 patients with a mean age at the first visit of 21 years. Twelve patients (92.3%) had a history of dislocation. Eleven patients (84.6%) had shoulder dislocations, and two patients (15.4%) had elbow dislocations. Four patients (30.8%) had elbow osteoarthritis, and three patients (23.1%) had distal radioulnar joint (DRUJ) osteoarthritis. The phalanges and metacarpals are thin, and the ratio of medullary cavity of the metacarpal bone decreases with age. As bone and joint deformity progresses, patients with mcEDS should be recommended to receive regular follow-up, including radiology. The present findings suggest an important role for dermatan sulfate in the maintenance of the skeletal system.

Novel Radiographic Indexes for Elbow Stability Assessment: Part B-Preliminary Clinical Study

INTRODUCTION

The coronoid process plays a key-role in preserving elbow stability. Currently, there are no radiographic indexes conceived to assess the intrinsic elbow stability and the joint congruency. The aim of this study is to present new radiological parameters, which will help assess the intrinsic stability of the ulnohumeral joint and to define normal values of these indexes in a normal, healthy population.

METHODS

Four independent observers (two orthopaedic surgeons and two radiologists) selected lateral view X-rays of subjects with no history of upper limb disease or surgery. The following radiographic indexes were defined: trochlear depth index (TDI); anterior coverage index (ACI); posterior coverage index (PCI); olecranon-coronoid angle (OCA); radiographic coverage angle (RCA). Inter-observer and intra-observer reproducibility were assessed for each index.

RESULTS

126 subjects were included. Standardized lateral elbow radiographs (62 left and 64 right elbows) were obtained and analysed. The mean TDI was 0.46 ± 0.06 (0.3-1.6), the mean ACI was 2.0 ± 0.2 (1.6-3.1) and the mean PCI was 1.3 ± 0.1 (1.0-1.9). The mean RCA was 179.6 ± 8.3° (normalized RCA: 49.9 ± 2.3%) and the mean OCA was 24.6 ± 3.7°. The indexes had a high-grade of inter-observer and intra-observer reliability for each of the four observers. Significantly higher values were found for males for TDI, ACI, PCI and RCA.

CONCLUSION

The novel radiological parameters described are simple, reliable and easily reproducible. These features make them a promising tool for radiographic evaluation both for orthopaedic surgeons and for radiologists in the emergency department setting or during outpatient services.

LEVEL OF EVIDENCE

Basic Science Study (Case Series).

CLINICAL RELEVANCE

The novel radiological parameters described are reliable, easily reproducible and become handy for orthopaedic surgeons as well as radiologists in daily clinical practice.