Early Joint Use Following Elbow Dislocation Limits Range-of-Motion Loss and Tissue Pathology in Posttraumatic Joint Contracture

Interspecies Comparison of Multilayer Mechanical Properties of Synovium Using Atomic Force Microscopy

The synovium is a loose connective tissue that separates the intra-articular (IA) joint compartments of all diarthrodial joints from the systemic circulation. It can be divided into two layers: the intima, a thin and cell-dense layer atop a more heterogeneous subintima, composed of collagen and various cell types. The subintima contains penetrating capillaries and lymphatic vessels that rapidly clear injected drugs from the joint space which may vary not only with drug size and charge but also with the microstructure and composition of the intima and subintima of the synovium. Prior work has measured the mechanical properties and solute diffusivities in the synovium of porcine, bovine, and human joints. Here, we measured the Young's moduli of synovium from smaller joints of the rat knee, as well as pig and human, using atomic force microscopy (AFM). The format for AFM enabled testing of intima and subintimal regions of synovium in all three species. The Young's moduli of the subintimal regions were similar across all three species (1-1.5 kPa). Furthermore, there was little evidence of differences in Young's moduli between synovium from the intima and subintima in each species. A general similarity of data from AFM testing with moduli measured with bulk testing of pig and human synovium suggests that AFM can be useful to measure the mechanical properties of smaller joint synovium and spatial variations in stiffness with depth. Enzymatic digestion of synovium tissue from the pig was also performed with findings of lower moduli values following treatment with chondroitinase ABC but not collagenase. Although the molecular composition of the synovium is not yet fully characterized and may vary across species, these findings suggest that noncollagenous species contribute to AFM-measured properties in synovium. These are some of the first data to measure mechanical properties in small joint synovium and will be useful in models studying IA drug clearances in joints with pathology and following treatment.

Is anterior transposition of the ulnar nerve necessary for post-traumatic elbow stiffness? A retrospective study

OBJECTIVE

To explore whether anterior transposition of the ulnar nerve is necessary in patients with post-traumatic elbow stiffness.

METHOD

This was a retrospective study of 177 patients with post-traumatic elbow stiffness treated at Shandong Provincial Hospital from 1 January 2012 to 31 October 2022. Sixty-one patients presented with ulnar nerve symptoms, and 116 patients had no nerve symptoms. Outcomes between patients with and without symptoms were compared using a range of clinical measures, namely range of motion (ROM), ulnar nerve symptoms, and various standardized scoring systems, namely, the Mayo Elbow Performance Score (MEPS), visual analog scale (VAS), improved Broberg and Morrey Score (BMS), Quick disabilities of the Arm, Shoulder, and Hand (DASH) score, Oxford Elbow Score (OES), and Amadio score.

RESULTS

Open elbow release surgery significantly improved elbow joint function in patients with post-traumatic elbow stiffness, regardless of the presence of ulnar nerve symptoms. Patients with ulnar nerve symptoms showed significant improvement after anterior transposition compared with in situ release. For patients without ulnar nerve symptoms, there was no significant difference in outcomes between the two types of ulnar nerve surgery.

CONCLUSION

Anterior transposition of the ulnar nerve is preferable for patients with ulnar nerve symptoms, while the choice between anterior transposition and in situ release can be individualized for patients without symptoms, based on intraoperative findings.

Weightlessness damaged the ultrastructure of knee cartilage and quadriceps muscle, aggravated the degeneration of cartilage

Background

Long-term exposure to weightlessness can result in bone and muscle degradation, significantly impacting musculoskeletal function. Recent studies have also indicated damage to articular cartilage due to weightlessness. This study aims to observe the effects of simulated weightlessness on the cartilage microstructure of the quadriceps muscle and the muscular knee joint in rats.

Methods

A total of 30 rats were used in this study, of which 20 rats were subjected to simulated weightlessness by tail suspension, which may be suitable for clinical long-term bedridden patients. At 14 and 28 days, the microscopic morphology of knee cartilage and quadriceps femoris muscle was observed by transmission electron microscopy, and the collagen and water content of cartilage was evaluated by magnetic resonance imaging. The mitochondrial activity of knee muscle and the levels of inflammatory factors in synovial fluid were detected by enzyme-linked immunosorbent assay (ELISA). Biomechanical and histological evaluation of cartilage was performed.

Results

On day 14, T2 mapping revealed no significant loading effect. However, transmission electron microscopy revealed altered mitochondrial inner membrane structure in cartilage, with vacuolization, disrupted endoplasmic reticulum, alongside mitochondrial ultrastructural damage in muscle. ELISA results showed that a large number of mitochondria in muscle were inactivated, and the levels of inflammatory factors in synovial fluid were increased. The staining results showed slight fracture of the cartilage surface and the type II collagen-positive cells were reduced. Nanoindentation showed that the cartilage microsurface was uneven, and the elastic modulus and hardness were decreased. On day 28, T2 mapping analysis indicated increased cartilage T2 values. Transmission electron microscopy showed alterations in the structure of the mitochondrial inner membrane in cartilage, severe vacuolization, disrupted endoplasmic reticulum, and substantial mitochondrial damage in muscle tissue. Muscle mitochondrial activity was markedly decreased, inflammatory factors levels were elevated, and the cartilage surface exhibited severe damage. The type II collagen positive cells were further reduced, the micro-surface of cartilage was uneven, and the elastic modulus and hardness were significantly decreased.

Conclusions

The weightless environment resulted in the damage of endoplasmic reticulum and mitochondria of cartilage, mitochondrial damage of quadriceps muscle, inactivation of muscle mitochondria (P=0.01), increased intra-articular inflammation (P=0.01), decreased elastic modulus and hardness (P=0.03), and damaged cartilage surface, which aggravated cartilage degeneration.

Simple acute postero-lateral elbow dislocation: A historical perspective

PURPOSE

The aims of this study were to summarize (1) the historical knowledge of the posterolateral elbow dislocation (PLED) pattern and the biomechanical, radiographic, and clinical data that engendered its evolution; and (2) to help clinicians better understand the management of PLED.

METHODS

A literature search was performed using Ovid, Scopus and Cochrane Library, and the Medical Subject Headings vocabulary. Results are discussed as a chronologic review of the relevant literature between 1920-2022.

RESULTS

In 1966 Osborn and Cotterill were the first to describe posterolateral rotatory instability (PLRI) causing the PLED. Several theories on PLED were then published by others surgeons as our understanding of elbow biomechanics continued to improve. Multiple treatment protocols have been designed based on the aforementioned theories. Conservative and surgical treatment for PLED provides excellent functional outcomes. However, high rates of persistent pain stiffness and instability have been reported long-term, and no single approach to treatment has been widely accepted.

CONCLUSION

Despite a growing body of biomechanical evidence, there is no consensus surgical indication for the treatment of PLED. Both conservative and surgical management result in satisfactory functional outcomes after PLED. However, elevated rates of residual pain, and instability have also been described and may limit heavy labor and sports participation. The next challenge for elbow surgeons will be to identify those patients who would benefit from surgical stabilization following PLED.

Neglected Elbow Dislocation leading to Ankylosis of Elbow: A Case Report

Introduction

Neglected elbow dislocation is defined as a dislocation that is present for 3 weeks or longer. There is no available literature on neglected elbow dislocations, leading to ankylosis of the elbow joint.

Case Report

A 17-year-old female sustained a road traffic accident. Anteroposterior and lateral view radiographs of the forearm were done and deemed to be normal at another hospital. Six months after the injury, she presented to us with complaints of absent elbow movements. Examination revealed the elbow to be fixed in 30° of flexion. Radiographs of the elbow revealed an ankylosis of the ulnohumeral articulation in an abnormal position.

Conclusion

This case demonstrates that neglected elbow dislocations can lead to ankylosis of the joint. It also shows how radiographs of the forearm are inadequate to assess for elbow dislocations even if the elbow region is covered in the radiograph.