Investigation of cryotherapy for pain relief after arthroscopic shoulder surgery

BACKGROUND: Recently, cryotherapy has become a common practice for postoperative pain management. The current accepted practice in Japan is the use of cryotherapy at 5 °C after arthroscopic shoulder surgery. However, this therapy has been reported to be highly intense because the sustained low temperature causes discomfort for patients. The optimum temperature and duration of cooling required for comfortable and effective cryotherapy after arthroscopic shoulder surgery were investigated. METHODS: Because pain levels might differ depending on the condition, we selected 52 patients with rotator cuff injuries, which were the most common disorders indicated for arthroscopic shoulder surgery. Patients were treated with cryotherapy at 5 °C or 10 °C for 16 h or 24 h. The pain level was determined using the visual analogue scale, and deep shoulder joint temperatures were recorded at different time points for analysis. RESULTS: Pain after arthroscopic shoulder surgery was found to be related to the presence of a brachial plexus block using the interscalene approach during surgical anesthesia. To obtain effective analgesia with cryotherapy, the cooling temperature and duration of cryotherapy had to be changed based on the presence or absence of the brachial plexus block. Patients who received brachial plexus blocks had the lowest recorded pain scores after receiving cryotherapy at 5 °C for 24 h after surgery. Patients who did not receive the block had the lowest recorded pain scores when receiving cryotherapy at either 5 °C for 16 h or 10 °C for 24 h. CONCLUSIONS: Using universal cryotherapy intensity and duration settings regardless of the use of other interventions is likely to unintentionally increase postoperative pain levels. This study revealed that cryotherapy at 5 °C for 24 h was optimal for patients who received an anesthesia block and at 5 °C for 16 h or at 10 °C for 24 h for those who did not receive the anesthesia block. These results can be used as a reference for setting the temperature and duration of cryotherapy after arthroscopic shoulder surgery.