Follow-up and Outcome of Operative Treatment With Decompressive Release Of The Peroneal Nerve

A Prospective, Multi-center, Randomized, Parallel-group Controlled Trial to Compare Conservative Versus Surgical Treatment of Foot Drop in Peroneal Nerve Entrapment.

The FOOT DROP trial is a prospective, multi-center, randomized controlled trial to assess if decompressive surgery for peroneal nerve entrapment is superior to maximal conservative treatment.

Patients with persisting foot drop due to peroneal nerve entrapment will be randomized to either surgery or conservative treatment if foot drop persists 10 +/- 4 weeks after onset of symptoms.

Patients will be evaluated through several questionnaires, evolution of muscle strength and several types of gait assessments. Primary endpoint is the difference in distance covered during the six minute walking test between baseline and 9 months after randomization.

The Foot Drop Trial is the first prospective, randomised controlled trial to investigate the treatment of foot drop in peroneal nerve entrapment. Currently, the literature consists mostly of biased retrospective case series with the exception of some small (biased) prospective case series. No comparative trials have been conducted. The goal of the trial is to assess whether foot drop due to peroneal nerve entrapment recovers better 9 months after decompressive surgery compared to maximal conservative treatment.

Patients with persisting foot drop (MRC score ankle dorsiflexion ≤ 3) after 10 +/- 4 weeks after onset of symptoms will be randomised to either decompressive surgery within 1 week after randomisation or maximal conservative treatment focussing on physiotherapy and gait rehabilitation. Blinded outcome assessors will evaluate participants at study visits 10 days (surgical group), 6 weeks, 3 months, 6 months, 9 months (primary outcome) and 18 months (extended follow-up) after randomization.

Outcome assessors will conduct several assessments to evaluate gait improvement (6-minute walk test, 10-meter walk test, Stanmore questionnaire, functional ambulation categories, ability to walk barefoot, need for foot-ankle orthosis), muscle strength (MRC score for ankle dorsiflexion, ankle eversion, hallux extension) , quality of life (EQ-5D 5L) and cost-effectiveness of both treatment strategies (work productivity and activity impairment questionnaire (WPAI), return to work, percentage of invalidity). Electrodiagnostic follow-up will be registered at 3 months and 9 months after randomization.

The primary endpoint of the foot drop trial is the difference in distance covered in meters during the six-minute walk test (6MWD) between baseline and 9 months after randomization. Time to recovery, defined as the time necessary to cover the minimal age- and sex-specific normal 6MWD AND the time necessary for foot drop recovery to an MRC-score ≥ 4 for ankle dorsiflexion is the key secondary endpoint. No cross-over to surgery is allowed before primary endpoint is reached.

The study first succesfully piloted in 6 centers in Belgium and the Netherlands and is currently starting on a large scale in 20 centers.

Inclusion Criteria:

• Written informed consent to participate in the study must be obtained from the subject or proxy / legal representative prior to initiation of any study-mandated procedure
• EDX-documented peroneal nerve entrapment with persisting (10 ± 4 weeks) foot drop (MRC-score ≤ 3)
• Imaging (ultrasound/MRI) performed to exclude a compressive mass
• Age ≥ 18 years

Exclusion Criteria:

• Subjects with posttraumatic or iatrogenic peroneal nerve injury
• Subjects with peroneal neuropathy due to a compressive mass (e.g. cyst, tumour)
• Peroneal nerve entrapment at other sites than the fibular head
• Patients with mental or physical problems that incapacitate them to participate in a physiotherapy program
• Psychiatric illness
• Pregnancy
• Planned (e)migration within 1 year after randomization to another country
• Subjects with previous foot drop
• Permanently bedridden subjects
• Subjects with neurological or musculoskeletal history which could impact foot drop assessment and/or gait analysis (e.g. polyneuropathy, hereditary neuropathy with pressure palsies, critical illness polyneuropathy, previous stroke, ankle surgery, …).