Glenn B. Pfeffer

Charcot–Marie–Tooth (CMT) disease is the most prevalent inherited peripheral neuropathy, characterized by progressive motor and sensory dysfunction resulting from a wide spectrum of genetic abnormalities. More than 70% of affected individuals develop cavovarus foot deformities, which impair gait mechanics, reduce functional mobility, and frequently necessitate orthotic support. The diagnosis of CMT-related foot deformity requires a comprehensive clinical evaluation, with particular emphasis on identifying muscle imbalance and assessing the function of individual musculotendinous units contributing to the deformity. Conservative management, including customized footwear and orthotic bracing, remains the first-line treatment for flexible and less severe deformities. However, surgical intervention should be considered in patients with progressive deformity, persistent symptoms, or failure of nonoperative treatment. Patients requiring surgical correction commonly present with a combination of cavovarus malalignment, muscle imbalance, soft-tissue contracture, and secondary osseous deformities. Current surgical management favors joint-sparing surgery through a combination of soft-tissue procedures, corrective osteotomies, and tendon transfer whenever feasible. Arthrodesis is generally reserved for rigid deformities that cannot be adequately corrected with joint-sparing surgery for patients with painful degenerative arthritis. When appropriately indicated, surgical reconstruction can substantially improve functional outcomes, reduce dependence on bracing, and enhance overall quality of life. This narrative review summarizes current concepts in the diagnosis and management of CMT-related cavovarus foot deformity, with particular emphasis on individualized deformity assessment and contemporary joint-sparing reconstruction.

Jae Hwang Song, Glenn Pfeffer. JKFAS 2025;29:16-26. https://doi.org/10.14193/jkfas.2025.29.1.16

Background: Charcot-Marie-Tooth (CMT) disease is a progressive inherited neurologic disorder causing muscle weakness and lower extremity deformity. The goal of foot and ankle surgical treatment is to create a stable, plantigrade foot, with the potential elimination of brace-wear for ambulation. The aim of this study was to report baseline CMT patient function and subsequent outcome improvement from surgical treatment, as determined by PROMIS physical function (PF), pain interference (PI), and mental health/depression (D) scores. Methods: Retrospective data were collected on consecutive CMT patients older than 18 years receiving surgical treatment by the senior surgeon at Cedars-Sinai Medical Center from 2018 to 2022 with minimum 1-year follow-up. Each patient prospectively completed PROMIS preoperatively and postoperatively after all planned surgical treatment was completed. Prospective clinical and radiographic data were collected to describe complications and correlation to outcome. Results: Ninety-five feet in 64 patients older than 18 years were included for analysis. Mean follow-up was 21 months (range, 12-31) with 100% minimum 1-year follow-up. CMT patients had worse preoperative and baseline scores in all domains except PROMIS-D compared with population normal PROMIS scores. Significant improvements were identified in all PROMIS domains following surgical treatment. The mean PROMIS-PF score increased (40 to 45, delta = 4.9, P < .001), the mean PROMIS-PI score decreased (59 to 52, delta = 7.1, P < .001), and the mean PROMIS-D score decreased (50 to 47, delta = 3.0, P = .004). Subgroup analysis was performed for patients with severe radiographic deformity and those treated with arthrodesis in an attempt to demonstrate the impact of disease severity on outcome. Subgroup analysis demonstrated that arthrodesis led to worse overall PROMIS-PF outcome with the same change score. Conclusion: Surgical treatment for CMT patients provides significant clinical improvement in all measured outcome domains. CMT patients can be restored to normal population physical function and pain interference outcome scores. Patients with more severe deformity have similar improvement from surgical treatment, although their ultimate functional improvement is blunted due to a lower baseline.

Charcot-Marie-Tooth disease (CMT) is the most common inherited peripheral polyneuropathy, resulting in length-dependent motor and sensory deficiencies. Asymmetric nerve involvement in the lower extremities creates a muscle imbalance, which manifests as a characteristic cavovarus deformity of the foot and ankle. This deformity is widely considered to be the most debilitating symptom of the disease, causing the patient to feel unstable and limiting mobility. Foot and ankle imaging in patients with CMT is critical for evaluation and treatment, as there is a wide range of phenotypic variation. Both radiography and weight-bearing CT should be used for assessment of this complex rotational deformity. Multimodality imaging including MRI and US is also important to help identify changes in the peripheral nerves, diagnose complications of abnormal alignment, and evaluate patients in the perioperative setting. The cavovarus foot is susceptible to distinctive pathologic conditions including soft-tissue calluses and ulceration, fractures of the fifth metatarsal, peroneal tendinopathy, and accelerated arthrosis of the tibiotalar joint. An externally applied brace can assist with balance and distribution of weight but may be appropriate for only a subset of patients. Many patients will require surgical correction, which may include soft-tissue releases, tendon transfers, osteotomies, and arthrodesis when necessary, with the goal of creating a more stable plantigrade foot. The authors focus on the cavovarus deformity of CMT. However, much of the information discussed may also be applied to a similar deformity that may result from idiopathic causes or other neuromuscular conditions. ^©RSNA, 2023 Quiz questions for this article are available through the Online Learning Center.

Category: Hindfoot; Midfoot/Forefoot Introduction/Purpose: The cavovarus deformity of Charcot-Marie-Tooth (CMT) disease typically presents with hindfoot varus and forefoot valgus. This seemingly paradoxical relationship is poorly understood. Better insight into this complex three- dimensional alignment under physiologic load-bearing conditions is possible using weight-bearing computed tomography (WBCT). This is the first study to examine the extreme rotational deformity in the midfoot of CMT patients, and thereby provides a key to the successful operative correction of the CMT cavovarus foot. Methods: We retrospectively reviewed the WBCTs of patients with CMT who presented to a single surgeon. Those with history of bony surgical correction, severe degenerative joint disease, or open physes in the foot, were excluded. Scans were analyzed using three-dimensional analysis software (Disior Bonelogic) to generate axes of select bones and their relationship relative to the tibial plafond anterior-posterior axis in the axial plane. The coronal alignment of the foot involved angular measurements of the calcaneus, talar dome, midfoot and forefoot relative to the ground. We reported quantitative alignment parameters and compared the measurements to WBCT of 20 controls. Results: 17 WBCT scans from 15 CMT patients (average age 24 years) met criteria for inclusion. In the axial plane, external rotation of the distal tibia accounted for the varus heel position rather than subtalar malalignment. The greatest change in axial alignment occurred between the talar neck and navicular (26 degrees). The average talonavicular (TN) medial uncoverage angle was -15 degrees for CMT patients, indicating medial overcoverage, compared to +11 degrees for controls, (p<0.01). Coronal plane analysis revealed varus rotational deformity at the calcaneus (23 degrees), a peak of 61 degrees varus across the navicular and cuboid, then compensatory rotation of the cuneiforms and metatarsals to achieve a plantigrade forefoot (11 degrees varus). In comparison, controls averaged 9 degrees coronal valgus at the calcaneus and 34 degrees varus at the naviculo-cuboid level, (p<0.01). Figure 1 shows the WBCT scans of a representative CMT patient and control case. Conclusion: This three-dimensional WBCT analysis is the first to characterize and quantify the axial and coronal rotational deformity in CMT. Axial plane deformity had a center of rotational angulation at the talonavicular joint, associated with medial ’overcoverage’ of the talar head, likely from chronic tibialis posterior over-pull. The peak coronal deformity was localized at the navicular and cuboid, which measured nearly twice as much as controls. These observations suggest dorsiflexion osteotomy of the 1st metatarsal would fail to address the coronal rotation; releases through the talonavicular joint may be necessary to abduct and de-rotate the midfoot to achieve a plantigrade foot.

Background: The cavovarus deformity of Charcot-Marie-Tooth (CMT) disease is often characterized by a paradoxical relationship of hindfoot varus and forefoot valgus. The configuration of the midfoot, which links these deformities, is poorly understood. Accurate assessment of 3-dimensional alignment under physiologic loadbearing conditions is possible using weightbearing computed tomography (WBCT). This is the first study to examine the rotational deformity in the midfoot of CMT patients and, thus, provide key insights to successful correction of CMT cavovarus foot. Methods: A total of 27 WBCT scans from 21 CMT patients were compared to control WBCTs from 20 healthy unmatched adults. CMT patients with a history of bony surgery, severe degenerative joint disease, or open physes in the foot were excluded. Scans were analyzed using 3-dimensional software. Anatomic alignment of the tarsal bones was calculated relative to the anterior-posterior axis of the tibial plafond in the axial plane, and weightbearing surface in the coronal plane. Results: Maximal rotational deformity in CMT patients occurred at the transverse tarsal joints, averaging 61 degrees of external rotation (supination), compared to 34 degrees among controls ( P < .01). The talonavicular joint was also the site of peak adduction deformity in the midfoot, with an average talonavicular coverage angle measuring 12 degrees compared with −11 degrees in controls ( P < .01). Conclusion: This 3-dimensional WBCT analysis is the first to isolate and quantify the multiplanar rotational deformity in the midfoot of CMT patients. Compared with healthy unmatched control cases, CMT patients demonstrated increased axial plane adduction and coronal plane rotation at the talonavicular (TN) joint. These findings support performing soft tissue release at the TN joint to abduct and derotate the midfoot as a first step for targeted deformity correction. Level of Evidence: Level III, retrospective case-control study.