Does Positive Ulnar Variance Require Surgery? A Comprehensive Guide

Introduction

Positive ulnar variance, a condition where the ulna is longer than the radius at the wrist joint, can be a source of significant discomfort and functional limitation for many individuals. But does this anatomical variation always require surgical intervention? Let's dive into the intricacies of this condition and explore the various treatment options available.

Understanding Positive Ulnar Variance

Ulnar variance refers to the relative lengths of the ulna and radius at the wrist joint. In positive ulnar variance, the ulna extends further distally than the radius, which can lead to increased pressure on the ulnar side of the wrist. This condition can be congenital or acquired, often resulting from distal radius fractures or growth plate injuries.

Symptoms and Diagnosis

Common symptoms of positive ulnar variance include:

• Ulnar-sided wrist pain
• Reduced grip strength
• Limited range of motion, especially in ulnar deviation
• Clicking or grinding sensations in the wrist

Diagnosis typically involves a combination of clinical examination and imaging studies. Colantoni et al. (2014) note that posteroanterior radiographs of the wrist are commonly used to assess ulnar variance. However, more advanced imaging techniques like CT or MRI may be necessary to evaluate associated soft tissue injuries.

Conservative Management

Not all cases of positive ulnar variance require surgery. Many patients can find relief through conservative measures, including:

1. Activity modification
2. Wrist splinting or bracing
3. Non-steroidal anti-inflammatory drugs (NSAIDs)
4. Physical therapy to improve wrist strength and flexibility
5. Corticosteroid injections for pain relief

When Is Surgery Necessary?

Surgery may be considered when conservative measures fail to provide adequate relief. According to Verhiel et al. (2022), factors that may indicate the need for surgical intervention include:

• Persistent pain despite conservative treatment
• Significant functional impairment
• Evidence of progressive ulnar-sided wrist degeneration
• Positive ulnar variance greater than 2-3 mm

Surgical Options

Several surgical procedures can address positive ulnar variance:

1. Ulnar Shortening Osteotomy (USO)

This is the gold standard for correcting positive ulnar variance. Lauder et al. (2007) describe USO as a procedure that involves removing a small section of the ulna and fixing it with a plate and screws. This effectively reduces the length of the ulna, alleviating pressure on the ulnar side of the wrist.

2. Wafer Procedure

For less severe cases, a wafer procedure may be performed. This involves removing a thin slice of bone from the distal ulna, either through an open approach or arthroscopically. Colantoni et al. (2014) note that this method is typically used for ulnar positive variance of less than 3 mm.

3. Arthroscopic Procedures

Advances in wrist arthroscopy have allowed for less invasive options. Yin et al. (2013) describe an arthroscopic technique for distal metaphyseal ulnar shortening, which offers the advantage of minimizing surgical injury to the dorsal capsule of the distal radioulnar joint.

Post-Surgical Considerations

Recovery from ulnar variance surgery typically involves:

• Immobilization in a cast or splint for 4-6 weeks
• Gradual return to activities over 3-6 months
• Physical therapy to regain strength and range of motion

It's important to note that while surgery can be effective, it's not without risks. Verhiel et al. (2022) reported a complication rate of 14% and a reoperation rate of 19% following arthroscopic procedures for ulnar-sided wrist pain.

Conclusion

Positive ulnar variance doesn't always require surgery, but it remains an important option for those who don't respond to conservative measures. The decision to undergo surgery should be made carefully, considering the severity of symptoms, degree of variance, and potential impact on quality of life. As with any medical condition, consultation with a hand specialist is crucial to determine the most appropriate treatment plan for each individual case.