What is the difference between posterolateral elbow instability, radial nerve compression, inflammatory osteoarthritis, osteochondritis dissecans, posterolateral plica, and primary osteoarthritis?

From the Guidelines

The key differences between these elbow conditions lie in their causes, symptoms, and affected structures, with posterolateral elbow instability, radial nerve compression, inflammatory osteoarthritis, osteochondritis dissecans, posterolateral plica, and primary osteoarthritis each having distinct characteristics and treatment approaches. The differences between these conditions can be understood by examining their underlying causes and symptoms. Posterolateral elbow instability results from ligament damage, causing the elbow to feel loose or unstable during certain movements, particularly when the forearm rotates 1. Radial nerve compression occurs when the radial nerve is pinched near the elbow, leading to weakness in wrist and finger extension, pain along the outer elbow and forearm, and sometimes numbness. Inflammatory osteoarthritis involves joint inflammation with more pronounced swelling, redness, and systemic symptoms compared to primary osteoarthritis, which is a degenerative condition characterized by gradual cartilage loss, pain with activity, stiffness, and crepitus without significant inflammation 1. Osteochondritis dissecans is a condition where a fragment of bone and cartilage separates from the joint surface, typically affecting younger patients with activity-related pain, catching, and locking. Posterolateral plica is an irritated fold of synovial tissue that causes pain specifically at the outer elbow during extension and flexion, often with a snapping sensation. Treatment approaches differ significantly:

• instability may require ligament reconstruction
• nerve compression needs decompression
• arthritis conditions respond to anti-inflammatories and activity modification
• osteochondritis may need surgical fixation
• and plica syndrome often requires excision of the irritated tissue 1. Imaging modalities such as CT and US can aid in the diagnosis of these conditions, with CT providing detailed images of fracture morphology and US offering a non-invasive means of evaluating tendinous and ligamentous structures 1.

Key characteristics of each condition include:

• Posterolateral elbow instability: ligament damage, instability during forearm rotation
• Radial nerve compression: weakness in wrist and finger extension, pain along the outer elbow and forearm
• Inflammatory osteoarthritis: joint inflammation, swelling, redness, and systemic symptoms
• Primary osteoarthritis: gradual cartilage loss, pain with activity, stiffness, and crepitus
• Osteochondritis dissecans: fragment of bone and cartilage separates from the joint surface, activity-related pain, catching, and locking
• Posterolateral plica: irritated fold of synovial tissue, pain during extension and flexion, snapping sensation. These differences are crucial for accurate diagnosis and effective treatment, as highlighted in recent studies 1.

From the Research

Differences in Diagnoses

The differences between diagnoses of posterolateral elbow instability, radial nerve compression, and inflammatory osteoarthritis, osteochondritis dissecans, posterolateral plica, and primary osteoarthritis can be identified through various clinical and imaging techniques.

• Posterolateral Elbow Instability: This condition is characterized by recurrent elbow instability caused by injury to the radial ulnohumeral ligament or lateral ulnar collateral ligament 2, 3, 4, 5. The diagnosis can be difficult due to challenging provocative tests, but diagnostic arthroscopy is an excellent tool to demonstrate this instability 2.
• Radial Nerve Compression: Although not directly mentioned in the provided studies, radial nerve compression can be distinguished from posterolateral elbow instability through clinical examination and imaging studies.
• Inflammatory Osteoarthritis: This condition is not directly discussed in the provided studies, but it can be differentiated from posterolateral elbow instability through clinical presentation, laboratory tests, and imaging studies.
• Osteochondritis Dissecans: This condition is not mentioned in the provided studies, but it can be identified through imaging studies such as radiographs, MRI, or CT scans.
• Posterolateral Plica: This condition is not discussed in the provided studies, but it can be diagnosed through arthroscopy or imaging studies.
• Primary Osteoarthritis: This condition is not directly mentioned in the provided studies, but it can be distinguished from posterolateral elbow instability through clinical presentation, laboratory tests, and imaging studies.

Diagnostic Techniques

Various diagnostic techniques can be used to differentiate between these conditions, including:

• Imaging Studies: Radiographs, MRI, and CT scans can be used to evaluate the elbow joint and surrounding structures 6.
• Arthroscopy: Diagnostic arthroscopy is an excellent tool to demonstrate posterolateral elbow instability and can also be used to evaluate other conditions such as osteochondritis dissecans and posterolateral plica 2, 4.
• Clinical Examination: A thorough history and physical examination are essential to establish the diagnosis of posterolateral elbow instability and other conditions 3, 5.