Mechanical Diagnosis and Therapy and Morton’s Neuroma: A Case Report

Abstract

Purpose: Morton’s neuroma (MN) is a neuralgia involving the common plantar digital nerves of the metatarsal region. Evidence-based treatment options for this condition are sparse, and physiotherapy’s usefulness is limited. Client Description: A woman aged 44 years was referred to physiotherapy for left forefoot pain lasting 3 months. The podiatrist diagnosed MN using ultrasonography. Examination found positive squeeze test, painful interphalangeals and metatarsal heads, and painful metatarsophalangeal joint (MPJ) extension. Intervention: Repeated flexion of MPJ digit II relieved the patient’s pain. She was treated six times over 3 months to progress treatment, achieve longer lasting pain relief, and recover function to full pain-free status, including running. Measures and Outcome: The patient’s pain reduced after treatment from a variable 2–7 out of 10 on the Numeric Pain Rating Scale to 0 out of 10. After two sessions, the patient’s Lower Extremity Functional Scale score improved, from 56 out of 80 to 70 out of 80, and by discharge, it was 73 out of 80. At 6-month follow-up, the patient was still running pain-free. Implications: This article describes the rapid and lasting improvement in chronic forefoot pain associated with MN after mechanical diagnosis and therapy assessment and treatment. Finding new, effective, conservative interventions is important for this condition because so few evidence-supported treatments exist. The findings from this case report demonstrate the benefit derived from exercise-based treatment and may indicate a role for physiotherapy in managing MN.

Symptomatic Morton’s neuroma (MN) is a common and painful condition of the foot.¹,² It is the most common neuropathy after carpal tunnel syndrome.³ A recent systematic review concluded that support for non-operative and operative management consisted of low-quality research and sample sizes or of poorly controlled case series.¹ The current podiatrist clinical practice guidelines do not include manual therapy or physiotherapy as a treatment option before surgical intervention to manage MN.⁴

Mechanical diagnosis and therapy (MDT) is a method of evaluation and treatment that uses end-range, repeated movements to evaluate the nature of pain and mechanical presentation.⁵.⁶ A clinician then makes a provisional classification (derangement, dysfunction, posture, or other) that guides the treatment approach.⁵,⁶ Using this method, patient-generated force exercises are an integral part of treatment, and they promote patient independence. There is no published application of an active self-treatment approach for MN. The patient consented to this case study being submitted to a medical journal with de-identified details.

CLIENT DESCRIPTION

History

A woman aged 44 years presented with a 3-month history of non-traumatic, left plantar forefoot pain. Ultrasonography identified that she had neuromas measuring 8 × 7 mm and 4 × 4 mm in the first and second web spaces, respectively. Walking and climbing stairs worsened her symptoms, and rest, not putting her weight on her foot, and applying ice improved them. Previous non-operative interventions – soft tissue massage, metatarsal and talocrural mobilizations, intrinsic and extrinsic foot and ankle strengthening, and metatarsal pad orthosis – had failed. Her functional limitation was an inability to run and limited tolerance for walking; previously, she had been a recreational runner. She had no pertinent surgical or medical history except for asthma.

Traditional physical examination results and outcomes

General observation found a slight metatarsophalangeal joint (MPJ) extension resting posture, and tenderness to palpation was most significant at MPJ II. Clinical tests – squeeze test and digital nerve stretch test – were positive.¹ Her baseline Lower Extremity Functional Scale (LEFS) score was 56 out of 80, and average resting pain was 2–4 out of 10 on the Numeric Pain Rating Scale (NPRS) but could increase to 7 out of 10 at worst. The LEFS is a valid and reliable, subjective outcome measure, with a minimal clinically important difference (MCID) of 9 points.⁷ The NPRS is a standard instrument for assessing level of pain, with an MCID of 2 points.⁸ The global rating of change (GROC) is a reliable and valid, 15-point Likert scale used to measure degree of perceived improvement during an episode of care; meaningful improvement is measured by a 5-point or higher change.⁹

MDT examination and assessment

Movement testing found painful extension of MPJ II and III at end range, with no movement loss, and painful flexion of MPJ II and III, with moderate movement loss. Single-leg heel raise and walking barefoot were painful. Three sets of 20 repetitions, unloaded MPJ flexion with clinician overpressure of MPJ II and III relieved the patient’s pain with walking, and she was able to complete five pain-free repetitions of single-leg heel raises. A provisional classification of derangement was made.

INTERVENTION

The patient was instructed to perform one set of 20 repetitions every 3 hours of unloaded MPJ flexion with self-overpressure (see Figure 1), with additional repetitions as needed when symptomatic.

Figure 1.

Unloaded flexion with self-overpressure.

Second visit

After 5 days, the patient reported a 75% perceived improvement relative to her overall condition and had returned to a walk–jog routine at the gym; NPRS was 2 out of 10 at worst. Because of persistent pain with toe walking, the exercise was progressed to partial-loaded MPJ flexion with self-overpressure (see Figure 2). The frequency recommendations remained the same, and the previous exercise was discontinued.

Figure 2.

Partial-loaded flexion with self-overpressure.

MEASURES AND OUTCOME

Third through sixth visit (discharge)

Three days later, the patient rated her pain as 0 out of 10 at worst on the NPRS and reported that she had increased her running to 3 miles. LEFS score was reassessed at 70 out of 80. The patient was instructed to continue with her current home exercise. The patient returned 48 days later after extended travel. Her baseline NPRS was 0 out of 10 at the start of each visit. She was able to perform 20 single-leg heel raises and toe walk without pain. Visits 4–6 were over a period of 36 days and were designed to return the patient to gym activities and to improve her cardiovascular endurance. By discharge, the digital nerve stretch test was negative, and the patient reported a LEFS score of 73 out of 80, a GROC score of +5 (quite a bit better), and an NPRS score of 0 out of 10. She had discontinued her use of metatarsal pad orthotics.

Six-month follow-up

At 6-month phone follow-up, the patient reported continuing her running activities with limitations secondary to asthma. She reported that she was able to self-manage without seeking further health care.

IMPLICATIONS

In this case, successful treatment was based on classifying the patient’s syndrome (symptomatic and mechanical response consistent with derangement) instead of targeted at the patho-anatomical or medical diagnosis of MN. Physiotherapy is not currently considered in the podiatric clinical practice guidelines for patients with suspected symptomatic MN,⁴ although Cashley and Cochrane supported exploration of manual therapy intervention in the presence of this diagnosis.² Instead, diagnosis and management are currently driven by imaging and clinical testing without including symptomatic response to mechanical and repetitive movement testing.

Manual therapy and manipulations have been shown to improve symptoms in the treatment of MN in podiatric or chiropractic medicine when using clinical tests such as the digital nerve stretch test for diagnosis.²,¹⁰,¹¹ Waldecker found success with implementing mobilization and manipulation in treating non-specific metatarsalgia, but there was no suggestion of potential self-treatment options.¹² Govender and colleagues contended that a component of unresolved pain in MN was explained by untreated, mechanically induced metatarsalgia, which may be more amenable to exercise intervention.¹¹ A proposed theoretical framework (shown in Figure 3), modified from the current podiatrist clinical practice guidelines,⁴ demonstrates the potential usefulness of physiotherapy in the examination, treatment, and triage process for those with MN.

Figure 3.

Proposed theoretical framework for managing Morton’s neuroma, modified from the current podiatrist clinical practice guidelines.

*Denotes new addition to current podiatrist clinical practice guidelines.⁴

CONCLUSION

A thorough mechanical assessment using repeated movements should be considered in the presence of an MN diagnosis. The current case shows that the patient responded favourably and her functional symptoms were resolved after MDT principles were applied with a treatment classification of derangement to guide her active self-management. Clinically, a derangement typically responds rapidly to intervention, given the appropriate loading strategies.⁵,⁶ Repeated movement testing can be used in early patient management, and in the differential diagnosis process, to facilitate patient care. Additional research is warranted to investigate the treatment effects of using MDT to examine and treat symptomatic patients with identified MN present.

KEY MESSAGES

What is already known on this topic

Morton’s neuroma (MN) is a neuralgia involving the common plantar digital nerves of the metatarsal region. Evidence-based treatment options for this condition are sparse, and the usefulness of physiotherapy is limited. There is no published application of an active self-treatment approach for MN.

What this study adds

This is the first published report on a patient with medically diagnosed MN who was treated with exercise-based, self-treatment therapy using principles of mechanical diagnosis and therapy. It is also the first case in physiotherapy that reports long-term outcomes for this diagnosis.