Operative management of foot and ankle equinovarus associated with focal dystonia

Functional dystonia: A pitfall for the foot and ankle surgeon

Functional dystonia represents a condition where psychological distress is being expressed as involuntary muscle contractions. In the foot and ankle, it most commonly presents as a sudden onset of a painful fixed ankle/hindfoot deformity in a female patient with a history of trivial trauma or surgery. The "fixed deformity" found on clinical examination is usually correctable under general anesthesia. Less commonly, it can present in the toes or may present as paroxysmal muscle movements rather than a fixed deformity. CRPS may occur concurrently with the dystonia. Failure to consider the diagnosis leads to a long delay in appropriate diagnosis, patient distress and unnecessary or even harmful surgery. A better approach to this clinical syndrome is to define it as fixed abnormal posturing that is most commonly psychogenic. Early referral to a movement disorder clinic is recommended. The prognosis is generally poor as less than a quarter of patients report subjective long-term improvement even when managed in a movement disorder clinic. Foot and ankle surgeons should, whenever possible, avoid operating on patients with functional dystonia in order to avoid symptomatic deterioration.

Surgical outcome of a post-traumatic dystonic foot: Case report and literature review

Post-traumatic dystonia is an underrecognized condition that can present with bizarre symptoms after trauma, usually out of proportion to the trigger event. We describe the case of a 31-year-old man with a severe lower extremity deformity, gradually developed after minor trauma. An interdisciplinary treatment was tried without any improvement and surgery was performed as a rescue approach. Tibialis anterior tendon transfer and hindfoot triple arthrodesis were carried out, successfully achieving a plantigrade foot and a functional gait. Despite the scarce literature available about functional results of surgery in dystonic feet, we present a step-by-step comprehensive approach to this disorder. LEVEL OF CLINICAL EVIDENCE: 4.

Dystonia and Parkinson's disease: What is the relationship?

Dystonia and Parkinson's disease are closely linked disorders sharing many pathophysiological overlaps. Dystonia can be seen in 30% or more of the patients suffering with PD and sometimes can precede the overt parkinsonism. The response of early dystonia to the introduction of dopamine replacement therapy (levodopa, dopamine agonists) is variable; dystonia commonly occurs in PD patients following levodopa initiation. Similarly, parkinsonism is commonly seen in patients with mutations in various DYT genes including those involved in the dopamine synthesis pathway. Pharmacological blockade of dopamine receptors can cause both tardive dystonia and parkinsonism and these movement disorders syndromes can occur in many other neurodegenerative, genetic, toxic and metabolic diseases. Pallidotomy in the past and currently deep brain stimulation largely involving the GPi are effective treatment options for both dystonia and parkinsonism. However, the physiological mechanisms underlying the response of these two different movement disorder syndromes are poorly understood. Interestingly, DBS for PD can cause dystonia such as blepharospasm and bilateral pallidal DBS for dystonia can result in features of parkinsonism. Advances in our understanding of these responses may provide better explanations for the relationship between dystonia and Parkinson's disease.

Management of pain in Parkinson's disease

Pain is a common symptom in Parkinson's disease (PD) and accounts for substantial morbidity in up to 80 % of patients. Despite contributing to disease-related discomfort and disability, pain in PD frequently goes underacknowledged and undertreated in clinical practice. Although the exact underlying neurophysiology is unclear, there is increasing understanding of the role of the basal ganglia in somatosensory processing, as well as involvement of additional brainstem structures and non-dopaminergic pathways; appreciation of these mechanisms has implications for treatment strategies. Categorizing painful symptoms based on their clinical description into musculoskeletal, dystonic, radicular-peripheral neuropathic and central pain categories provides a useful framework for management. Importantly, these symptoms should be evaluated in relation to motor symptoms and dopaminergic therapy. A multi-disciplinary approach is recommended as follows: physical therapy, liaison with pain management and consultations to rheumatological, orthopaedic and neurosurgical services should be considered.

Lateral and medial plantar pressures after split versus whole anterior tibialis tendon transfer

BACKGROUND

If whole and split transfer of the anterior tibialis tendon (SPLATT) do not differ in balancing the forefoot, whole tendon transfer would provide a simpler alternative as part of treatment of an equinovarus deformity. We hypothesized that no significant differences in percent plantar lateral forefoot pressures would be observed between split and whole tendon transfer. We used a spastic model to test the hypothesis that overcorrection would not occur with whole tendon transfer.

MATERIALS AND METHODS

In ten specimens from five lower extremity matched pairs, a SPLATT was anchored to the cuboid. After loading, simulated whole tendon transfer to the lateral cuneiform was done. Normal loading was Achilles, 250 N, tibialis anterior, 200 N, peroneals/tibialis posterior, 142 N; and spastic loading was Achilles, 500 N, tibialis anterior, 400 N, peroneals/tibialis posterior, 142 N. Pressure data were collected for both normal and spastic conditions. Percent of forefoot pressure was calculated for the lateral and medial sector.

RESULTS

Percent lateral pressure was slightly lower after whole tendon transfer (normal, p < 0.01; spastic, p < 0.01). This difference was not clinically important. Medial pressure did not differ in the spastic versus the normal model after split or whole tendon transfer.

CONCLUSION

Whole and split anterior tibialis tendon transfer both resulted in a balanced forefoot. Neither whole tendon nor split tendon transfer resulted in overcorrection in a simulated spastic model.

CLINICAL RELEVANCE

Whole tendon transfer may be an effective and simpler alternative to SPLATT for unloading the lateral forefoot in both a normal and a spastic foot.

Striatal deformities of the hand and foot in Parkinson's disease

Striatal deformities of the hand and foot are abnormal postures that are common in patients with advanced Parkinson's disease (PD); they can present in the early stages of PD and in other parkinsonian disorders. Over a century ago, Charcot and Purves-Stewart recognised these deformities, which cause substantial functional disability and discomfort. The term striatal is used because pathology in the neostriatum (putamen and caudate) has been suggested to cause the deformities, but the pathogenesis is unknown. Misdiagnosis of the deformities is common-particularly when they occur early and in the absence of cardinal parkinsonian signs, such as tremor, bradykinesia, and rigidity-because the hand deformities are similar to those in rheumatoid arthritis, equinovarus foot deformity typically suggests an orthopaedic problem, and toe extension may be thought to be the Babinski sign of upper-motor-neuron syndromes. Here we review the background and clinical features of these deformities to highlight these commonly unrecognised and poorly understood parkinsonian signs.

[Restoration of the ability to walk through bilateral triple arthrodesis in marked spastic pes equinovarus]

A tendon transfer is the method of choice in easily reducible pes equinovarus. However, in long-time persisting deformities with spasms, a plantigrade position can not be maintained with these procedures. Therefore, we perform an additional bilateral triple arthrodesis in a patients with such bilateral deformities. A 55-year-old woman developed, within the scope of several surgical procedures on the cervical spine, marked bilateral pes equinovarus and flexion contractures of the knees. The patient's ambulation was limited to a wheelchair for 3 years. Then, in an interval of 1 year, we performed an unilateral soft tissue release, z-tenotomy of the Achilles tendon, triple arthrodesis with correction of the deformity, and posterior tibial tenden transfer. At follow-up 5 years after the second procedure, the 61-year-old patient was able to walk alone with two walking sticks. In the case described, the correction of a marked pes equinovarus with spasms, which was achieved by an extensive soft tissue release, could be stabilized through a triple arthrodesis in such way that the plantigrade position of the foot could be controlled through a posterior tibial tendon transfer.

Dystonia and parkinsonism

Parkinsonism and dystonia may coexist in a number of neurodegenerative, genetic, toxic, and metabolic disorders and as a result of structural lesions in the basal ganglia. Parkinson's disease (PD) and the 'Parkinson-plus' syndromes (PPS) account for the majority of patients with the parkinsonism-dystonia combination. Dystonia, particularly when it involves the foot, may be the presenting sign of PD or PPS and these disorders should be suspected when adults present with isolated foot dystonia. Young age, female gender, and long disease duration are risk factors for PD-related dystonia, but dystonia in patients with PD is usually related to levodopa therapy. The mechanism of dystonia in PD is not well understood and the management is often challenging because levodopa and other dopaminergic agents may either improve or worsen dystonia. Other therapeutic strategies include oral medications (baclofen, anticholinergics and benzodiazepines), local injections of botulinum toxin, intrathecal baclofen, and surgical lesions or high frequency stimulation of the thalamus, globus pallidus, or subthalamus.