Clinical Research Directory

Multiple studies have shown that vibration sources applied to muscles prior to exercise reduced soreness and lactate dehydrogenase production, and increased range of motion at 48 and 72 hours. Acute pain results from fast A nerves transmitting nociceptive information to the dorsal column, where the substantia gelatinosa's interneurons prioritize competing A mechanoreceptor and C-fibers to slow pain transmission. One study observed that stimulation of A mechanoreceptors "shut the gate" on pain transmission, an inhibitory mechanism known as "gate control". Multiple physical methodologies leverage gate control physiology for pain relief, such as vibratory massage therapy and electrical stimulation to varying degrees. However, the use of vibratory massage to improve pain control and reduce opioid use following ACLR has not been well studied, and to our knowledge there are no randomized control trials (RCTs) evaluating the use of this modality compared to standard ice or cryocompression.

Cryotherapy has also been used as an adjunctive post-operative therapy to reduce pain and inflammation following anterior cruciate ligament reconstruction (ACLR). It has been shown to decrease local metabolism, resulting in reduced pain and inflammation. Multiple studies have shown the benefits of using cryotherapy after ACLR, and more recently dynamic intermittent compression has been shown to improve circulation while reducing the risk of skin necrosis associated with static permanent compression. A recent meta-analysis including ten RCTs found significant reductions in post-operative VAS pain scores and breakthrough opioid consumption when using cryotherapy, such as Game Ready or Breggs ice therapy, following ACLR.

Cold also provides peripheral gate-control relief via small, slow C-Fibers that transmit low level pain. In addition to local pain relief, intense cold can raise the A pain threshold distant to the location. The mechanism has been called descending or diffuse noxious inhibitory relief, or more recently conditioned pain modulation (CPM). Injections, aches, and infiltration of local anesthesia and dermal fillers are relieved by applying cold. For acute injury, near freezing cold relieves pain by suppressing the local metabolic production of inflammation and concomitant tissue ischemia from hypoxia due to the increased metabolic rate.