The key nursing intervention that prevents footdrop in a client with osteomyelitis is using a footboard, posterior splint, or high-top sneakers to keep the foot at a 90-degree angle to the lower leg. This position, called dorsiflexion, stops the foot from dropping into a downward position during prolonged bed rest or immobilization. Because osteomyelitis often requires weeks of limited mobility, maintaining this neutral ankle position is essential to protecting the nerve responsible for lifting the foot.
Why Osteomyelitis Creates Footdrop Risk
Osteomyelitis is a bone infection that typically requires long periods of immobilization, whether through bed rest, casting, or splinting. During this time, the common peroneal nerve, which wraps around the bony bump just below the outer knee, becomes vulnerable. This nerve controls your ability to pull your foot upward and is the most commonly injured nerve in the lower leg. When a patient lies in bed for extended periods, the weight of blankets pushing the foot downward, combined with pressure on the outer knee from the mattress, can compress or stretch this nerve.
Swelling from the infection itself can also contribute. If the osteomyelitis involves the lower leg, inflammation near the knee area may press on the nerve directly. A cast or splint that fits poorly around the outer knee creates additional compression risk. The result is weakness or complete inability to lift the foot, a condition called footdrop that can become permanent if the nerve is damaged long enough.
Supportive Positioning Devices
The primary intervention is placing a device that holds the ankle at 90 degrees, preventing the foot from pointing downward. Several options accomplish this:
- Footboard: A flat board placed at the end of the bed so the soles of the feet press against it, keeping the ankles in a neutral position. This also prevents heavy bedding from pushing the feet down.
- Posterior leg splint: A rigid or semi-rigid splint applied to the back of the lower leg and foot that locks the ankle at 90 degrees. This is especially useful when the patient is wearing a cast that doesn’t extend to the foot.
- High-top sneakers: Laced firmly, these hold the ankle in dorsiflexion and allow some protected movement. They’re practical for patients who are partially mobile.
- Ankle-foot orthosis (AFO): A lightweight brace worn inside or outside clothing that maintains foot position during both rest and early walking.
For exam purposes, the footboard is the most commonly tested answer. In clinical practice, the choice depends on the patient’s mobility level and whether a cast is already in place.
Repositioning and Pressure Relief
Positioning devices alone aren’t enough. The common peroneal nerve sits in a superficial position right at the outer side of the knee, where even moderate pressure from a mattress or bed rail can cause damage. Nursing interventions to address this include repositioning the patient every two hours and placing padding under the outer knee to lift it off the bed surface. When the patient is lying on their side, a pillow between the knees prevents the upper leg from compressing the nerve on the lower leg.
If the patient has a cast or plaster immobilizer, the skin around the edges needs daily inspection for redness or irritation. Cotton padding can be placed at pressure points to reduce friction. The weight of a cast itself can shift the leg into positions that compress the nerve, so adjusting body mechanics when moving the patient is important.
Neurovascular Checks
Regular assessment catches early nerve involvement before permanent damage sets in. The checks are straightforward: ask the patient to pull their foot upward toward their shin (dorsiflexion) and to turn the sole of the foot outward (eversion). Weakness in either movement signals possible peroneal nerve compression. You should also check for numbness or tingling along the top of the foot and the outer lower leg, particularly in the webspace between the first and second toes.
A quick bedside test involves tapping along the nerve’s path near the outer knee. If this produces tingling or a pins-and-needles sensation shooting down toward the foot, that’s a positive Tinel sign, indicating the nerve is irritated or compressed at that point. These checks should be part of routine neurovascular assessment, performed at least every shift and more frequently in the first days of immobilization.
Range-of-Motion Exercises
Unless the affected bone is in the ankle or foot and movement is restricted, gentle range-of-motion exercises help maintain nerve function and prevent the Achilles tendon from tightening. Ankle circles, alternating between pointing the toes up and down, and rotating the foot inward and outward all keep the muscles and tendons around the ankle flexible. These can be passive (performed by the nurse) if the patient can’t do them independently, or active if the patient is able.
Even a few minutes of ankle exercises several times a day makes a meaningful difference over weeks of immobilization. The goal is preventing the calf muscles and Achilles tendon from shortening into a fixed downward position, which would make footdrop harder to reverse even after the nerve recovers.
What Patients Should Watch For
Patients and families need to understand why foot positioning matters and what early warning signs look like. Difficulty lifting the front of the foot, tripping or catching toes on the ground when starting to walk again, and new numbness on the top of the foot all warrant immediate attention. For patients in a cast, any increasing tightness, new tingling, or skin color changes visible at the edges of the cast should be reported right away, as swelling inside the cast can worsen nerve compression quickly.
Teaching family members to check that the footboard or splint stays in proper position is practical and simple. Devices shift during sleep or when the patient moves in bed, and a footboard that’s slipped out of contact with the soles isn’t doing its job.