From the Guidelines
Ulna positive variant is best evaluated using dynamic US to demonstrate nerve dislocation in ulnar nerve neuropathy and snapping triceps syndrome, as it provides high accuracy rates in assessing cross-sectional area and nerve thickness 1. When considering the evaluation of ulna positive variant, it is essential to prioritize diagnostic methods that provide accurate assessments of nerve thickness and cross-sectional area.
- The use of US elbow for evaluation offers several advantages, including high accuracy rates in assessing nerve thickness and cross-sectional area 1.
- Dynamic US is particularly helpful in demonstrating nerve dislocation in ulnar nerve neuropathy and snapping triceps syndrome, making it a valuable diagnostic tool for ulna positive variant 1.
- Shear-wave elastography is a newer method that has shown promising results, with reported values of 100% specificity, sensitivity, and both positive and negative predictive value for the diagnosis of ulnar neuropathy at the elbow 1. In terms of management, the focus should be on addressing any symptoms or functional limitations associated with the ulna positive variant, while also considering the potential for long-term degenerative changes.
- Conservative treatment options, such as activity modification, anti-inflammatory medications, and physical therapy, may be sufficient for asymptomatic or mildly symptomatic cases.
- For more severe cases, surgical interventions like ulnar shortening osteotomy may be necessary to restore proper wrist biomechanics and alleviate persistent pain or functional limitations.
From the Research
Ulna Positive Variant
- The ulna positive variant is a condition where the ulna bone is longer than the radius bone, leading to an overload on the ulnar carpus and potentially causing ulnar impaction syndrome (UIS) 2.
- Studies have shown that patients with ulnar positive variance may not respond well to arthroscopic debridement of degenerative triangular fibrocartilage complex (TFCC) lesions, and may require additional surgery such as ulnar shortening osteotomy (USO) 3.
- Ulnar shortening osteotomy has been shown to be an effective treatment for UIS, with significant reductions in pain and improvements in functional outcomes 2, 3.
- The goal of ulnar shortening osteotomy is to reduce the ulnar variance to zero or negative, in order to alleviate the overload on the ulnar carpus and improve symptoms 2, 4.
- However, some studies have suggested that the degree of radiological change in cystic lunate lesions and clinical improvement after ulnar shortening osteotomy may not differ significantly between patients with unintended residual positive and negative variance after shortening 4.
Treatment Options
- Arthroscopic debridement of degenerative TFCC lesions may be effective for patients with ulnar neutral or negative variance, but may not be sufficient for patients with ulnar positive variance 3.
- Ulnar shortening osteotomy is a common operative treatment option for UIS, and has been shown to be effective in reducing pain and improving functional outcomes 2, 3.
- Other treatment options, such as non-steroidal anti-inflammatory drugs (NSAIDs) and physical therapy, may also be used to manage symptoms of UIS, but may not address the underlying cause of the condition 5, 6.
Outcomes
- Studies have shown that patients with ulnar positive variance who undergo ulnar shortening osteotomy can expect significant reductions in pain and improvements in functional outcomes, with some studies reporting long-term follow-up of up to 10 years 2, 3.
- However, the degree of improvement may vary depending on the individual patient and the specific treatment used, and some patients may require additional surgery or interventions to achieve optimal outcomes 3, 4.