Methylprednisolone Injections for the Treatment of Morton Neuroma: A Patient-Blinded Randomized Trial

SLR- January 2014- Anna Wojcik

Reference: Thomson CE, Beggs I, Martin DJ, McMillan D, Edwards RT, Russell D, Yeo ST, Russell IT, Gibson JN. Methylprednisolone Injections for the Treatment of Morton Neuroma: A Patient-Blinded Randomized Trial. JBone Joint Surg Am. 2013 May 1; 95(9):790-8.

Methods: A pragmatic, patient-blinded randomized trial was established and set within at three recruiting centers in Edinburgh, United Kingdom during a 24 month period. Following specific inclusion and exclusion criteria, 131 participants were identified with Morton neuroma. Eighty-five percent of the participants were female and their mean age was 53. The participants were randomized and blinded to receive either corticosteroid and anesthetic (1 mL methylprednisolone [40 mg] and 1 mL 2 percent lignocaine) oranesthetic alone (2 mL 1 percent lignocaine). A musculoskeletal radiologist performed an ultrasonographic image was obtained before treatment and diagnosed a Morton neuroma when a soft-tissue mass measuring ≥5 mmin diameter when compressed was identified between adjacent metatarsal heads.The same musculoskeletal radiologist performed injections with the needle placed under ultrasonographic guidance through a plantar approach. The primary outcome was the difference in patient global assessment of foot health between the two groups at three months after injection. This was measured with use of a 100-unit visual analog scale (VAS) anchored by "best imaginable health state" and "worst imaginable health state."

Results: The global assessment of foot health in thecorticosteroid group was significantly better at three months compared with the control group, (mean difference, 14.1 scale points [95 percent confidence interval, 5.5 to 22.8 points]; p = 0.002). The difference between the groups was also significant at one month. Significant and nonsignificant improvements associated with the corticosteroid injection were observed for measures of pain, function, and patient global assessment of general health at one and three months after injection. The size of the neuroma as noted by ultrasound did not significantly influence the treatment effect. No significant adverse effects were noted in either groups. Three patients (5 percent) in the corticosteroid group had developed hypopigmentation of the dorsal skin over the injection site at three months, and two (3 percent) showed atrophy of the plantar fat pad at three months.

Conclusions: Morton neuroma is a common cause of neuralgiain the forefoot affecting the interspaces. Many patients undergo surgery to excise the hypertrophied nerve, which is thought to the cause of the pain. This surgical procedure, however, is reported to have many associated complications and reoccurrences. According to this study, corticosteroid injections are reported to be of symptomatic benefit for at least three months for Morton neuroma. These results allow the practitioner to use corticosteroid injections as a first line therapy before performing any surgical intervention.