Jump to content

Foot drop

Original Editor - Abbey Wright

Top Contributors - Abbey Wright, Lokiru Paul, Misha Ahir, Kim Jackson, Admin and Lucinda hampton

Introduction

Foot drop, also known as drop foot, is not a disease in itself but rather a clinical sign indicative of an underlying neurological, anatomical, or muscular disorder. It is characterized by the inability to dorsiflex the foot—i.e., lift the forefoot—due to weakness or paralysis of the dorsiflexor muscles of the ankle and foot.[1] Weakness in the ankle and foot dorsiflexors results in a varus deformity. Sometimes referred to as steppage gait, which is a tendency of a person walking with an exaggerated flexion of the hip and knee to prevent the toes from catching on the ground during the swing phase. Foot drop can therefore hinder walking and increase the risk of tripping and falling. [2]An ankle foot orthoses (AFO) is the brace used for foot drop.

Clinically Relevant Anatomy

The common peroneal nerve is the smaller and terminal branch of the sciatic nerve which is composed of the posterior divisions of L4,L 5, S1, S2. The nerve can be palpated behind the head of the fibula and as it winds around the neck of the fibula.[3]Deep branch of common peroneal nerve runs into the anterior compartment of the leg and then over the ankle to the dorsum of the foot. It supplies all of the muscles of the anterior compartment, i.e dorsiflexors, as well as providing a cutaneous supply to the area between the 1st and 2nd toes.

The primary dorsiflexors include the tibialis anterior, extensor digitorum longus, and extensor hallucis longus. These muscles play a crucial role in gait mechanics: they help elevate the foot during the swing phase of walking and control plantar flexion at heel strike.[4]

Mechanism of Injury

Lesion site localisation of foot drop can be challenging because it may be a presentation of a range of pathologic conditions that localise along the full course of upper and lower motor neurone pathways, which often overlap in clinical presentation.[5][6] The Mechanism of injury can be divided into three groups.

1. Compression disorders: Entrapment syndromes of the fibular nerve at various locations along its anatomical pathway can lead to compressive neuropathy. The common fibular neuropathy at the fibular head is the most common mononeuropathy affecting the leg.[7] The fibular nerve being so superficial near the head of the fibula makes it vulnerable to pressure palsies.  Weight loss, prolonged bedridden status, tight casts, space-occupying lesions, and bone metastasis involving the fibular head can be other contributing factors. Compression of the fibula head during surgery, e.g. tourniquet[8]

Sciatic nerve compression between the two heads of the piriformis muscle, leading to foot drop, has been reported.

Compression palsies in the ICUs have been known to occur because of protracted bed rest. It is that 10% of patients who stay in the ICU for a period longer than four weeks are expected to develop paresis of the fibular nerve. Critical illness polyneuropathy involving multiple motor and sensory nerves can also present with foot drop.[5] Depending on the extent of involvement, weakness can be bilateral. Patients with diabetes are more vulnerable to these compression neuropathies.

Another common cause of foot drop is Lumbar radiculopathy. L5 radiculopathy is the most common lumbar radiculopathy and results from lumbar disc herniation or spondylitis in the spine.[6]Compression of the L5 nerve from disc herniations and bony (osteophytes or sacral ala) or ligamentous (sacroiliac ligament and lumbosacral band) compression is known to occur.[7]

2. Traumatic Injuries: They often occur associated with orthopedic injuries such as TKA[8],Fracture to tibial plateau[9], Patellar dislocations (33% chance of nerve damage)[10], Ankle inversion injury.[11]Sciatic neuropathy commonly resulting from either a traumatic injury of the hip or secondary to surgery, is the second most common mononeuropathy of the lower extremity and typically presents with foot drop.[12]Lumbosacral plexopathies, resulting from traumatic injury, a complication of abdominal or pelvic surgery, or a complication of neoplasm or radiation therapy, is less common cause of foot drop.

3. Neurologic Disorders: Charcot–Marie Tooth (CMT) is one of the most commonly inherited congenital demyelinating peripheral neuropathy. It affects both motor and sensory nerves. The incidence is 1 in 25000. One of the main symptoms is foot drop and wasting of the lower leg muscles, giving a typical “stork leg” appearance.[13]

Stroke[14] can present as hemiplegia, of which foot drop is part of this presentation. Other signs of upper motor neuron involvement, such as increased muscle tone, hyperreflexia, and circumduction of the lower extremity during ambulation, are also seen. Depending on the location of ischemia, aphasia can be present.

Clinical Presentation

Typical presentation of foot drop can be noted when testing the foot and ankle in isolation, however, in a clinical setting, it may be identified initially through gait assessment.

Foot and Ankle Assessment: When testing the foot and ankle, a positive test for foot drop is no active dorsiflexion in a non-weight-bearing position. It is important to test passive ROM to ensure the ankle is not stiff. See the foot and ankle examination page for a full assessment of the foot and ankle.

GAIT Assessment: Foot drop gait can manifest in different ways, varying from patient to patient. Some patients may increase the amount of hip flexion they produce on the affected side therefore, clearing the floor more effectively:

EmbedVideo is missing a required parameter.

[15] Other patients may circumduct the hip and drag the forefoot along the floor:

EmbedVideo is missing a required parameter.

[16]

Pain

Neurogenic pain can be experienced from damage to the common peroneal nerve. This pain can be present over the lateral aspect of the knee as well as the dorsal part of the foot.Sensory changes can also be experienced, indicating nerve damage to the therapist.[17]

Diagnostic Procedures

  • Subjective History: emphasis on any knee trauma, recent spinal/peripheral limb surgery or family history of neurological disease
  • Assessment of ankle dorsiflexion
  • Neurological exam[17]
  • Gait assessment
  • Electromyography (EMG) / Nerve conduction studies[18][11]

Outcome Measures

Most commonly used are:

Management / Interventions

Following palsy of the common peroneal nerve, the main residual symptom can be foot drop due to the disruption to L4/5 muscle groups, which perform dorsiflexion. This has been shown to resolve in two-thirds of patients by one year post-injury. [8]Pain should also be addressed if the patient is experiencing neuropathic pain by use of appropriate analgesia. [17]

  1. Splintage: One way to improve function while the foot drop resolves is the use of splinting. A solid ankle-foot orthoses (AFO) or foot-up splint can be used to keep the foot in plantar-grade. These work to increase the amount of dorsiflexion the foot is held in during gait and can prevent falls as the toes do not get caught on the floor.
Ankle-Foot orthoses used for foot drop
Ankle-Foot orthoses used for foot drop

2. Exercise: Physiotherapy interventions normally are focused on graded exercises to encourage active dorsiflexion and muscle recruitment. These exercises have been shown to prevent atrophy and speed up recovery but more research is needed.[8]

In neurologically impaired patients such as Charcot‐Marie‐Tooth disease improved with strengthening exercises to tibialis anterior; however, in other neurological diseases, like muscular dystrophy, strength training was not found to be effective at reducing the foot drop. [20]

Preventing contractures and stiffness is also an important maintenance goal of physiotherapy. Electro-stimulation of the affected muscle groups has also been shown to improve recovery times.[8]

3. Surgery: Surgery for foot drop is considered for patients with chronic foot drop that hasn't responded to conservative treatments. Direct repair of the common peroneal nerve is immediate surgical intervention; however, this has been shown to have poor outcomes with residual foot drop leading to further surgery.[21]Tendon transfer is the most common surgical procedure. The tibialis posterior is transposed from the posterior compartment to the anterior compartment to regain active dorsiflexion. since , this tendon not innervated by the common peroneal nerve, this surgery has been shown to be more successful than nerve repair.[9][21][19]After tendon transfer foot is immobilized in 20 degrees of dorsiflexion in below-knee posterior splint for 4 weeks followed by rehabilitation exercises. In cases of compression, neurolysis and nerve decompression at fibular tunnel is a surgical option. Surgery is successful at improving active dorsiflexion strength and reduced use of AFOs.[22]

Resources

Stanmore assessment

References

  1. ↑ Stewart JD. Foot drop: where, why and what to do?. Pract Neurol. 2008 Jun. 8 (3):158-69. [QxMD MEDLINE Link].
  2. ↑ Stevens F, Weerkamp NJ, Cals JW. Foot drop. BMJ 2015;350:h1736.
  3. ↑ Palastanga N & Soames R Anatomy and Human Movement, Structure and Function. 6th ed. China: Elsevier(Churchill Livingstone) Limited; 2012.
  4. ↑ Gage JR. An overview of normal walking. Instr Course Lect 1990;39:291–303.
  5. ↑ 5.0 5.1 Baima J, Krivickas L. Evaluation and treatment of peroneal neuropathy. Curr Rev Musculoskelet Med 2008;1(2):147–153.
  6. ↑ 6.0 6.1 Stewart JD. Foot drop: where, why and what to do? Pract Neurol 2008;8(3):158–169.
  7. ↑ 7.0 7.1 van Zantvoort A, Setz M, Hoogeveen A, van Eerten P, Scheltinga M. Chronic lower leg pain: entrapment of common peroneal nerve or tibial nerve. Unfallchirurg. 2020 Jan;123(Suppl 1):20-24. [PubMed] [Reference list]
  8. ↑ 8.0 8.1 8.2 8.3 8.4 Park JH, Restrepo C, Norton R, Mandel S, Sharkey PF, Parvizi J. Common peroneal nerve palsy following total knee arthroplasty: prognostic factors and course of recovery. The Journal of arthroplasty. 2013 Oct 1;28(9):1538-42
  9. ↑ 9.0 9.1 Baima J, Krivickas L. Evaluation and treatment of peroneal neuropathy. Current reviews in musculoskeletal medicine. 2008 Jun 1;1(2):147-53.
  10. ↑ Henrichs A. A review of knee dislocations. Journal of athletic training. 2004 Oct;39(4):365.
  11. ↑ 11.0 11.1 Brief J M, et al. Peroneal Nerve Injury with Foot Drop Complicating Ankle Sprain A Series of Four Cases with Review of the Literature. Bulletin of the NYU Hospital for Joint Diseases. 2009;67(4):374-7
  12. ↑ Distad BJ, Weiss MD. Clinical and electrodiagnostic features of sciatic neuropathies. Phys Med Rehabil Clin N Am. 2013 Feb;24(1):107-20. [PubMed] [Reference list]
  13. ↑ Pisciotta C, Shy ME. Neuropathy. Handb Clin Neurol. 2018;148:653-665. [PubMed] [Reference list]
  14. ↑ Everaert DG, Stein RB, Abrams GM, Dromerick AW, Francisco GE, Hafner BJ, Huskey TN, Munin MC, Nolan KJ, Kufta CV. Effect of a foot-drop stimulator and ankle–foot orthosis on walking performance after stroke: a multicenter randomized controlled trial. Neurorehabilitation and neural repair. 2013 Sep;27(7):579-91.
  15. ↑ Steppage Gait. Judy Mishriki Available from: https://www.youtube.com/watch?v=TijuPg8_JhY [last accessed 02/09/2013]
  16. ↑ Alaine Wambe MD. Right slap gait/steppage gait/foot drop in a post operative patient. Available from: https://www.youtube.com/watch?v=EjPUpKUbZSg [last accessed 11/03/2019]
  17. ↑ 17.0 17.1 17.2 Baima J, Krivickas L. Evaluation and treatment of peroneal neuropathy. Current reviews in musculoskeletal medicine. 2008 Jun 1;1(2):147-53.
  18. ↑ Masakado Y, Kawakami M, Suzuki K, Abe L, Ota T, Kimura A. Clinical neurophysiology in the diagnosis of peroneal nerve palsy. The Keio journal of medicine. 2008 Jun 25;57(2):84-9.
  19. ↑ 19.0 19.1 Lingaiah P, Jaykumar K, Sural S, Dhal A. Functional evaluation of early tendon transfer for foot drop. Journal of Orthopaedic Surgery. 2018 Sep 19;26(3):2309499018799766.
  20. ↑ Sackley C, Disler PB, Turner‐Stokes L, Wade DT, Brittle N, Hoppitt T. Rehabilitation interventions for foot drop in neuromuscular disease. Cochrane Database of Systematic Reviews. 2009(3).
  21. ↑ 21.0 21.1 Özkan T, Tuncer S, Ozturk K, Aydin A, Ozkan S. Tibialis posterior tendon transfer for persistent drop foot after peroneal nerve repair. Journal of reconstructive microsurgery. 2009 Apr;25(03):157-64.
  22. ↑ Hove LM, Nilsen PT. Posterior tibial tendon transfer for drop-foot: 20 cases followed for 1–5 years. Acta Orthopaedica Scandinavica. 1998 Jan 1;69(6):608-10.
Retrieved from "https://www.physio-pedia.com/w/index.php?title=Foot_drop&oldid=370455"