Methods:
This single-center, retrospective study reviewed electronic medical records of patients aged 18-75 who underwent ulnar nerve decompression and/or transposition (CPT 64718) between January 2015 and December 2022. Exclusion criteria included trauma, revision surgery, or prior elbow procedures. Operative notes, EDS, ultrasound, clinic notes, and demographics were reviewed. Indications for transposition were extracted from documentation.
Results:
Among 1,327 included cases, 1,019 underwent in situ decompression, 282 had subcutaneous transpositions, and 26 had submuscular transpositions. Patients who received transposition were younger (mean 49.6 vs. 55.5 years, p < 0.001) and had lower BMI (30.5 vs. 32.3, p < 0.001). EDS severity, gender, and race were similar across groups (Figure 1).
Of 27 surgeons, 14 performed ?10 cases. Orthopedic surgeons performed 94.1% of cases, while neurosurgeons performed 4.7% of total cases but 14.2% of all transpositions. Nineteen surgeons performed at least one transposition; nine performed submuscular transpositions (Figure 2).
Of the 309 transpositions, 74.8% were due to ulnar nerve instability (subluxation, perching, dislocation, or hypermobility), identified preoperatively, intraoperatively, or both. Interestingly, instability was noted in 3.1% of patients who were left in situ and in 6.2% of cases intraoperatively without resulting in transposition. Additional transposition rationales included symptom severity, EMG findings, or muscle weakness (3.6%), and surgeon preference such as prior contralateral transposition (4.2%). In 17.5% of cases, rationale was unclear or undocumented, though some referenced findings similar to those that led to transposition in other cases (Figure 3).
Conclusion:
Most transpositions were performed for documented nerve instability, but a substantial proportion were based on other or unclear reasons. Not all unstable nerves were transposed, suggesting varied surgeon thresholds. Differences in rationale and documentation reflect variation in surgeon training and preference. These findings highlight the need for clearer guidelines and standardized documentation to support consistent surgical decision-making. 
