Predictors of functional outcomes after simple decompression for ulnar neuropathy at the elbow: a multicenter study by the SUN study group.

OBJECTIVE

To identify predictors of surgical outcome for ulnar neuropathy at the elbow (UNE).

DESIGN

Prospective cohort followed for 1 year.

SETTING

Clinics.

PARTICIPANTS

Patients diagnosed with UNE (N=55).

INTERVENTION: All subjects had simple decompression surgery.

MAIN OUTCOME MEASURES: The primary outcome measure was patient-reported outcomes, such as overall hand function through the Michigan Hand Outcomes Questionnaire (MHQ). Predictors included age, duration of symptoms, disease severity, and motor conduction velocity across the elbow.

RESULTS

Multiple regression models with change in the overall MHQ score as the dependent variable showed that at 3 months postoperative time, patients with <3 months duration of symptoms showed 12 points (95% confidence interval [CI], 0.9-23.5) greater improvement in MHQ scores than those with ≥3 months symptom duration. Less than 3 months of symptoms was again associated with 13 points (95% CI, 2.9-24) greater improvement in MHQ scores at 6 months postoperative, but it was no longer associated with better outcomes at 12 months. A worse baseline MHQ score was associated with significant improvement in MHQ scores at 3 months (coefficient, -0.38; 95% CI, -.67 to -.09), and baseline MHQ score was the only significant predictor of 12 month MHQ scores (coefficient, -.40; 95% CI, -.79 to -.01).

CONCLUSIONS

Subjects with <3 months of symptoms and worse baseline MHQ scores showed significantly greater improvement in functional outcomes as reported by the MHQ. However, duration of symptoms was only predictive at 3 or 6 months because most patients recovered within 3 to 6 months after surgery.