Impact of Charcot neuroarthropathy on metatarsal bone mineral density and geometric strength indices

Trabecular and cortical bone microarchitecture using high-resolution peripheral quantitative computed tomographic imaging in diabetic peripheral neuropathy

CONTEXT

Type 2 Diabetes Mellitus (T2D) is associated with an increased risk of fragility fracture despite normal areal bone mineral density (BMD). The contribution of diabetic peripheral neuropathy (PN) to volumetric BMD (vBMD) and bone microarchitecture in T2D is not explored.

OBJECTIVE

To assess vBMD and microarchitectural properties of bone using high-resolution peripheral quantitative computed tomography (HR-pQCT) in patients of T2D with or without PN.

DESIGN

This is a cross-sectional study of patients of T2D divided into two groups [patients with T2D without PN (Group A) and T2D with PN (Group B)]. All patients underwent clinical examination, biochemical evaluation, dual-energy X-ray absorptiometry (DXA), and HR-pQCT of the radius and tibia.

RESULTS

A total of 296 patients were included in the study [Group A (n = 98), Group B (n = 198)]. HR-pQCT demonstrated a significant difference in total vBMD[mg/cm3] at tibia (291.6 ± 61.8 vs. 268.2 ± 63.0; p-0.003); cortical vBMD[mg/cm3] at tibia [912.5 (863.3, 962.4) vs. 853.8 (795.3, 913.2) p-0.000], among groups A and B respectively. Among the microarchitecture parameters, there was a significant difference in cortical porosity at the tibia (2.5% ±1.7% vs. 3%±1.7%; p-0.004), trabecular number[mm-1] at the tibia [1.080 (0.896, 1.237) vs. 1.140 (0.983, 1.286), p-0.045] and trabecular thickness[mm] at the radius [0.228 (0.217, 0.247) Vs. 0.238 (0.224, 0.253); p-0.006], among groups A and B respectively.

CONCLUSION

Despite comparable areal BMD, T2D patients with PN have diminished vBMD and deteriorated skeletal microarchitecture, compared to those without PN.

Guidelines on the diagnosis and treatment of active Charcot neuro-osteoarthropathy in persons with diabetes mellitus (IWGDF 2023)

The International Working Group on the Diabetic Foot (IWGDF) has published evidence-based guidelines on the prevention and management of diabetic foot disease since 1999. This is the first guideline on the diagnosis and treatment of active Charcot neuro-osteoarthropathy in persons with diabetes published by the IWGDF. We followed the GRADE Methodology to devise clinical questions in the PACO (Population, Assessment, Comparison, Outcome) and PICO (Population, Intervention, Comparison, Outcome) format, conducted a systematic review of the medical literature, and developed recommendations with the rationale. The recommendations are based on the evidence from our systematic review, expert opinion when evidence was not available, and also taking into account weighing of the benefits and harms, patient preferences, feasibility and applicability, and costs related to an intervention. We here present the 2023 Guidelines on the diagnosis and treatment of active Charcot neuro-osteoarthropathy in persons with diabetes mellitus and also suggest key future topics of research.

Prevalence of Ankle Charcot Neuroarthropathy Presenting in a Tertiary Care Center

Charcot neuroarthropathy's (CN) anatomic classification was originally formulated by the Brodsky article and the Trepman et al modification, including midfoot (type 1), rearfoot (type 2), ankle (type 3a), calcaneus (type 3b), multiarticular (type 4), and forefoot (type 5). In these classic studies, ankle joint and multijoint CN are reported as 9% and 6% to 9%, respectively, but we believe ankle CN to be more common than that in a tertiary setting. We retrospectively reviewed patients presenting initially or as referral between 2004 and 2020. Initial presentation radiographs were reviewed and classified by 3 authors based on Brodsky's model with Trepman and colleagues' modification, and any discrepancies were reviewed by the fourth author. A total of 175 patients (205 feet) were assessed. This revealed 80 cases classified as type 1 (39.0%), 23 cases type 2 (11.2%), 17 cases type 3a (8.3%), 2 cases type 3b (1.0%), and 83 cases type 4 (40.5%). After subdividing type 4, total prevalence included 150 with type 1 anatomic location (73.2%), 103 type 2 (50.2%), 44 type 3a (21.5%), and still 2 type 3b (1.0%). This study revealed a similar prevalence of isolated ankle CN (8.5%) compared to the Trepman et al article (9%), however, in total, ankle CN (21.5%) occurred 2.4-times more than the original 9%. Our study also found there to be a higher prevalence of ankle CN in the setting of multiarticular CN, which has not been evaluated in past studies. The prevalence of multiarticular CN was found to be 4.5-fold greater than the Trepman article (6%-9%).

Radiodensity Analysis of Lateral Column Superconstruct Fixation Sites in Midfoot Charcot Neuroarthropathy

Lateral column deterioration and subsequent loss of function poses a challenge for limb preservation in patients with Charcot neuroarthropathy (CN). Application of "superconstructs" provides stability and clinical improvement to an often-ulcerated lateral foot. This study examines radiodensity in Hounsfield units (HU) to compare bone quality of lateral column fixation targets using computed tomography (CT) scans between patients with and without midfoot CN. A retrospective chart review identified control (nondiabetic, non-CN; n = 29) and midfoot CN (n = 21) groups. Patient demographics and medical history were collected. Two reviewers measured the mean HU of circular regions of interest centered on the fourth and fifth metatarsal heads as well as the anterior, middle, and posterior thirds of the calcaneus. Radiodensity was compared between groups, among calcaneal locations, Eichenholtz stages and Brodsky types. A p value ≤.05 was considered statistically significant. Age and body mass index were not significantly different between groups. The CN group exhibited greater HU than the control group at the metatarsal head and calcaneus (p < .001). The anterior calcaneus exhibited greater HU than the posterior calcaneus in the CN group (p = .02). The difference in HU was not statistically significant between Stages 0-1 and Stages 2-3 or midfoot Brodsky Types. Indirect bone density analysis revealed an increased density in CN compared to control patients with no significant difference between midfoot CN stages or types. The anterior calcaneus was the densest rearfoot bone among the CN patients, a result that may have implications in surgical fixation.

Functional outcomes of tibiotalocalcaneal arthrodesis using a hindfoot arthrodesis nail in treating Charcot's arthropathy deformity

Background

Tibiotalocalcaneal arthrodesis or hindfoot fusion is a salvage surgical option used to treat symptomatic or severe deformity as a result of Charcot's arthropathy. It is an internal fixation that utilizes nails to stabilize the hindfoot after surgical correction of the deformity. This study intends to measure the change in functional outcomes of patients with Charcot's arthropathy using this technique and the time taken to achieve fusion.

Method

This study presents a series of 40 cases of Charcot's arthropathy where hindfoot fusion was done using a hindfoot arthrodesis nail. A retrospective analysis was done where these patients' functional scores had been evaluated preoperatively and postoperatively (serially) with the Short-Form Health Survey 36 (SF-36), American Orthopedic Foot and Ankle Society (AOFAS), Foot and Ankle Outcome Score (FAOS), and Foot Function Index (FFI). Along with its complication, the length of time required for the fusion is also reported.

Results

This study consists of 40 patients (13 men, 27 women; mean age 60.5 years; age range 52-68 years) with a mean follow-up of 64 months (range 24-108 months). The mean time taken for fusion was 5.1 months. All patients showed improvement in functional scoring (SF-36, AOFAS, FFI, and FAOS) postoperatively. We establish that the improvements were gradual over 2 years. Approximately 37.5% of patients had a minor complication and 2.5% had a major complication.

Conclusion

Hindfoot fusion using a hindfoot arthrodesis nail results in improved functional outcome with an acceptable fusion time and acceptable complication rate.

Level of evidence

Level III.

Biomarkers of chronic kidney disease-mineral bone disorder (CKD-MBD) in the diabetic foot: A medical record review

AIMS

Determine the prevalence and relative risk of having single and combinations of biomarkers of chronic kidney disease-mineral bone disorder (CKD-MBD) syndrome in the diabetic foot from an electronic medical record (EMR) review.

METHODS

Review of 152 patients with one foot radiograph and diagnoses of both diabetes mellitus (DM) and chronic kidney disease (CKD) stages 1-5. Presence/absence of peripheral neuropathy (PN), targeted serum markers, and both pedal vessel calcification (PVC) and buckling ratio (BR) of 2nd and 5th metatarsals from radiographs were recorded. Prevalence of single and combinations of foot biomarkers are reported as count and percentage. Risk ratios (RR) with 95% confidence intervals (95% CI) were calculated to assess risk of foot biomarkers in each stage of CKD-MBD.

RESULTS

Prevalence and RR of PVC, PN, and BR ≥ 3.5 biomarkers, both single and in combination, all increase with progression of CKD. The RR increases to 9.6 (95 % CI: 3, 26; p < 0.001) when all 3 biomarkers present in stage 5.

CONCLUSIONS

PVC, PN, and BR ≥ 3.5 are prognostic biomarkers of CKD-MBD syndrome in the diabetic foot. Recognition of these foot biomarkers may allow earlier interventions to help reduce nontraumatic lower extremity amputation in individuals with diabetic CKD-MBD.

Radiodensity Analysis of Medial Column Superconstruct Fixation Sites in Midfoot Charcot Neuroarthropathy

Charcot neuroarthropathy (CN) is a highly destructive, pathologic process with devastating consequences to foot structure and viability. The use of intramedullary fixation "superconstructs" allows for "re-bar" support of compromised bone and allows for some dynamic fixation. This study examines radiodensity in Hounsfield units (HU) to compare bone quality of medial column fixation targets using computed tomography scans between patients with and without midfoot CN. A retrospective chart review identified control (nondiabetic, non-CN; n = 29) and midfoot CN (n = 21) groups. Patient demographics and medical history were collected. Two reviewers measured the mean HU of a circular region of interest centered on the first metatarsal head and the anterior, middle, and posterior thirds of the talar body. Radiodensity was compared between groups, and among talar locations, Eichenholtz stages and Brodsky types, with statistical significance set at p ≤ .05. Age and body mass index were not significantly different between groups. The CN group maintained greater mean HU than the control group at the metatarsal head (p < .001), and talar body locations (p < .019). The difference in mean HU of these bones was not statistically significant between Stages 0 to 1 and Stages 2 to 3 or Brodsky Types 1 and 2. Mean HU differences among talus positions were not statistically significant. Indirect bone density analysis using HU showed an increased density in CN patients with no significant difference among talar body locations or midfoot Charcot stages and types. These results may assist in optimizing fixation length. Future studies may examine these densities in ankle CN.

Accelerated Cortical Osteolysis of Metatarsals in Charcot Neuroarthropathy: A Cross-Sectional Observational Study

Metatarsals are frequent sites of stress and fragility fractures in younger athletic populations and aging older adults. Metatarsal fractures are particularly common in Charcot neuroarthropathy (CN), a complication of diabetes mellitus (DM) and peripheral neuropathy (PN). Neuropathic metatarsal fractures may be caused by an accelerated cortical bone osteolysis and may be reflected as geometric-derived strength estimates from standard foot radiographs. The purpose of this cross-sectional study was to determine geometry and strength-derived estimates of the metatarsals in individuals with DM, PN, and CN compared with younger and older adult controls who were nondiabetic and nonneuropathic. We studied 62 participants: 20 young adult controls (YACs), 22 older adult controls (OACs), and 20 diagnosed with DMPN&CN. From weight-bearing radiographs, we measured the outer diaphysis diameter and inner marrow diameter at the distal, middle, and proximal diaphysis sites of the second and fifth metatarsal. From these diameters, we derived strength estimates of combined cortical width (CCt.Wi), percent cortical area (%Ct.rA), buckling ratio (BR), moment of inertia (MOI), and section modulus (SM) at each site in both metatarsals. DMPN&CN participants had an accelerated cortical thinning, decreased %Ct.Ar, increased BR, and lower MOI and SM compared with OACs and YACs. The OACs showed age-related decreases in CCt.Wi and % Ct.Ar, and increased BR. The BR demonstrated significant group × bone × site interaction with the distal fifth metatarsal in the DMPN&CN group having the lowest bone strength. The BR in the distal fifth metatarsal of DMPN&CN participants was 36% and 49% greater than in the OAC and YAC groups, respectively. DMPN&CN participants have lower metatarsal bone strength estimates compared with younger and older adult controls. Standard foot radiographs demonstrate an accelerated cortical osteolysis in DMPN&CN individuals, particularly in the distal fifth metatarsal diaphysis. © 2019 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research © 2019 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

A Candidate Imaging Marker for Early Detection of Charcot Neuroarthropathy

Inflammation-mediated foot osteopenia may play a pivotal role in the etiogenesis, pathogenesis, and therapeutic outcomes in individuals with diabetes mellitus (DM), peripheral neuropathy (PN), and Charcot neuroarthropathy (CN). Our objective was to establish a volumetric quantitative computed tomography-derived foot bone measurement as a candidate prognostic imaging marker to identify individuals with DMPN who were at risk of developing CN. We studied 3 groups: 16 young controls (27 ± 5 years), 20 with DMPN (57 ± 11 years), and 20 with DMPN and CN (55 ± 9 years). Computed tomography image analysis was used to measure metatarsal and tarsal bone mineral density in both feet. The mean of 12 right (7 tarsals and 5 metatarsals) and 12 left foot bone mineral densities, maximum percent difference in bone mineral density between paired bones of the right and the left feet, and the mean difference of the 12 right and the 12 left bone mineral density measurements were used as input variables in different classification analysis methods to determine the best classifier. Classification tree analysis produced no misclassification of the young controls and individuals with DMPN and CN. The tree classifier found 7 of 20 (35%) individuals with DMPN to be classified as CN (1 participant developed CN during follow-up) and 13 (65%) to be classified as healthy. These results indicate that a decision tree employing 3 measurements derived from volumetric quantitative computed tomography foot bone mineral density defines a candidate prognostic imaging marker to identify individuals with diabetes and PN who are at risk of developing CN.

Persistent inflammation with pedal osteolysis 1year after Charcot neuropathic osteoarthropathy

AIMS

To determine local and systemic markers of inflammation and bone mineral density (BMD) in the foot and central sites in participants with diabetes mellitus and peripheral neuropathy (DMPN) with and without acute Charcot neuropathic osteoarthropathy (CN).

METHODS

Eighteen participants with DMPN and CN and 19 participants without CN had foot temperature assessments, serum markers of inflammation [C-reactive protein, (CRP) and erythrocyte sedimentation rate, (ESR)] and BMD of the foot, hip and lumbar spine at baseline and 1year follow-up.

RESULTS

CN foot temperature difference was higher compared to DMPN controls at baseline (4.2±1.9°F vs. 1.2±0.9°F, P<0.01) and after 1year (2.9±3.2°F vs. 0.9±1.1°F, P<0.01). Serum inflammatory markers in the CN group were greater at baseline and remained elevated 1year later compared to DMPN controls (CRP, P=0.02, ESR, P=0.03). All pedal bones' BMD decreased an average of 3% in the CN foot with no changes in hip or lumbar spine. DMPN controls' foot, hip and lumbar spine BMD remained unchanged.

CONCLUSIONS

Local and systemic inflammation persists 1 year after CN with an accompanying pedal osteolysis that may contribute to mid foot deformity which is the hallmark of the chronic Charcot foot.

A new insole measurement system to detect bending and torsional moments at the human foot during footwear condition: a technical report

Background

Stress occurring at the feet while wearing footwear is often determined using pressure measurement systems. However, other forms of stress, such as bending, torsional and shear loadings, cannot be detected in shoes during day-to-day activities. Nevertheless, the detection of these types of stresses would be helpful for understanding the mechanical aspects of various kinds of hard and soft tissue injuries. Therefore, we describe the development of a new measuring device that allows the reliable determination of bending and torsional load at the foot in shoes.

Methods

The system consists of a measuring insole and an analogue device with Bluetooth interface. The specific shape of the insole base layer, the positions of the strain gauges, and the interconnections between them have all been selected in such a way so as to isolate bending and torsional moment detections in the medial and lateral metatarsal region. The system was calibrated using a classical two-point test procedure. A single case study was executed to evaluate the new device for practical use. This application consisted of one subject wearing neutral shoes walking on a treadmill.

Results

The calibration results (coefficients of determination R² > 0.999) show that bending and torsional load can be reliably detected using the measurement system presented. In the single case study, alternating bending and torsional load can be detected during walking, and the shape of the detected bending moments can be confirmed by the measurements of Arndt et al. (J Biomech 35:621–8, 2002).

Conclusions

Despite some limitations, the presented device allows for the reliable determination of bending and torsional stresses at the foot in shoes.

Pedal bone density, strength, orientation, and plantar loads preceding incipient metatarsal fracture after charcot neuroarthropathy: 2 case reports

STUDY DESIGN

Case report.

BACKGROUND

Charcot neuroarthropathy is a progressive, noninfective, inflammatory destruction of bones and joints leading to foot deformities and plantar ulceration. Though individuals with Charcot neuroarthropathy typically have low areal bone mineral density, little is known regarding changes in volumetric bone mineral density (vBMD), bone geometry, joint malalignment, and biomechanical loads preceding fracture.

CASE DESCRIPTION

Two women, aged 45 and 54 years at the onset of an acute, nonfracture Charcot neuroarthropathy event, received regular physical therapy with wound care and total-contact casting. Both enrolled in a larger research study that included plantar pressure assessment and quantitative computed tomography at enrollment and 3, 6, and 12 months later. The women sustained mid-diaphyseal fifth metatarsal fracture 10 to 11 months after enrollment. Quantitative computed tomography image-analysis techniques were used to measure vBMD; bone geometric indices reflecting strength in compression, bending, and cortical buckling; and 3-D bone-to-bone orientation angles reflecting foot deformity.

OUTCOMES

Fifth metatarsal mid-diaphyseal vBMD decreased during offloading treatment from 0 to 3 months, then increased to above baseline levels by 6 months. All geometric strength indices improved from baseline through 6 months. Plantar loading in the lateral midfoot increased preceding fracture, concomitant with alterations in bone orientation angles, which suggest progressive development of metatarsus adductus and equinovarus foot deformity.

DISCUSSION

Fractures may occur when bone strength decreases or when biomechanical loading increases. Incipient fracture was preceded by increased loading in the lateral midfoot but not by reductions in vBMD or geometric strength indices, suggesting that loading played a greater role in fracture. Moreover, the progression of foot deformities may be causally linked to the increased plantar loading.

LEVEL OF EVIDENCE

Prognosis, level 4.