A review of the literature took stock of the evidence of efficacy currently available for therapeutic cannabis treatment of acute and chronic pain associated with conditions involving the upper limbs.
Although it is used to treat pain associated with various conditions and diseases, such as chronic neuropathic and oncological pain, the analgesic efficacy of medical cannabis in the management of acute and chronic musculoskeletal pain needs to be further investigated.
In this regard, a group of US surgeons presented and discussed in a recently published article the state of the art of knowledge on the efficacy, safety and potential applications of medical cannabis in hand surgery and in the treatment of conditions involving upper limb pain in general.
Cannabis and hand pain: what is known
According to the results of a survey of more than 600 patients followed in hand surgery centres, about 10 per cent used medical cannabis, while 8 out of 10 of those who did not use it said they were willing, if prescribed by a doctor, to consider this option to treat an orthopaedic condition.
Clinical studies conducted so far have provided conflicting results on the efficacy of medical cannabis in the treatment of acute postoperative and traumatic pain: high-quality evidence is limited and mainly concerns monotherapy and comparison with placebo, while with respect to other active comparators, the indications from the studies do not allow firm conclusions to be drawn.
One field of application that seems to have good prospects is the treatment of chronic non-oncological pain, for which the positive results of some clinical studies conducted in the musculoskeletal field could be extended to the hand. Indeed, among the mechanisms generating chronic pain in the upper limbs is degenerative or inflammatory arthritis, and preclinical studies and research in animal models have demonstrated the interaction between the endocannabinoid system and inflammation, arthrosis-related pain and disease progression.
Clinical evidence is limited, but promising: a systematic review of 36 trials comparing therapeutic cannabis with placebo in the treatment of chronic non-oncological pain indicated significantly greater efficacy of cannabis in reducing pain scale scores, regardless of the route of administration, although the difference was not clinically relevant.
Furthermore, due to its anti-inflammatory and nociceptive effects, cannabidiol (CBD) could be useful in the treatment of arthritis of inflammatory origin, such as rheumatoid or psoriatic arthritis, although more solid evidence is needed. A Cochrane review on the use of cannabinoids to combat rheumatoid arthritis-related pain concluded that cannabis can improve pain levels and sleep quality, although there was no solid evidence of its superiority over placebo.
The use of medical cannabis could then play an important role in counteracting neuropathic pain, a condition that in the case of the hand and upper limbs is a challenge. In fact, cannabinoids have been shown to be effective in alleviating neuropathic pain associated with multiple sclerosis and HIV. In particular, one study analysed the effects of medical cannabis on post-traumatic and post-operative neuropathic pain, finding a significant reduction in symptom intensity and an improvement in sleep quality in the group of patients treated with high-dose THC.
In view of the good prospects suggested by these results, studies aimed at specifically assessing the efficacy of therapeutic cannabis in neuropathic pain of the hand and upper limbs are needed to see whether they can actually be extrapolated to the specific field.
The most promising applications
“Currently, the evidence supporting the use of medical cannabis in the musculoskeletal setting is limited, but very promising, for chronic non-oncological and neuropathic pain, while it is insufficient to support its use in acute post-traumatic or post-operative pain” comment the authors. “Treatment with medical cannabis should be considered for patients with chronic or neuropathic pain of the hand and upper limbs due to conditions that cannot be treated surgically or following failure of non-surgical treatments, in individuals with long-term or increasing dependence on opioid analgesia. However, further targeted studies in this area are needed”, the researchers conclude.
Reference
Yang A, Townsend CB, Ilyas AM. Medical cannabis in hand surgery: a review of the current evidence. J Hand Surg Am. 2023;48(3):292-300.
