Persistent inflammation with pedal osteolysis 1year after Charcot neuropathic osteoarthropathy

Effect of denosumab on inflammation and bone health in active Charcot foot: A phase II randomised controlled trial

AIMS

We aimed to investigate the effect of denosumab on pedal bone health and clinical resolution in active Charcot foot (CN).

METHODS

This multicentre open-label phase 2 randomised controlled trial recruited adults with diabetes mellitus and active CN within 3 months of onset. Participants were randomised to standard care alone, or with denosumab 60 mg subcutaneously. Denosumab was administered at baseline and again at 6 months, unless foot temperature had normalised (i.e. <2 °C compared to contralateral foot). Co-primary outcomes were change in calcaneal Stiffness Index and foot temperature normalisation over 18 months.

RESULTS

Twelve participants per group were analysed; mean age 58 ± 11 years, 83 % male and 92 % had type 2 diabetes. Active CN duration was median 8 (IQR 7-12) weeks. Ninety-two percent were Eichenholtz stage 1 and 96 % involved the midfoot. After 1-month, median decline in Stiffness Index was less in the denosumab verses standard care group (0.5 [IQR -1.0 to 3.9] vs -2.8 [-8.5 to -1.0], p = 0.008). At 18-months, 92 % of the denosumab group attained foot temperature normalisation versus 67 % of the standard care group (p = 0.13).

CONCLUSIONS

Denosumab ameliorated the early decline in calcaneal Stiffness Index associated with active CN. However, no difference in normalisation of foot temperature was observed.

Offloading of Diabetic Neuropathic Plantar Ulcers: Secondary Analysis of Step Activity and Ulcer Healing

OBJECTIVE

Although it is well-known that offloading devices facilitate healing in people with diabetes and neuropathic plantar ulcers, little is known about how step activity affects healing. The purposes of this study were to compare: (1) healing outcomes (time to healing, percentage of ulcers healed); (2) healing rates by ulcer location; and (3) step activity (daily step count, daily peak mean cadence) among patients using either total contact casts (TCCs) or removable cast walker boots (RCWs).

METHODS

The study included 55 participants (TCC, 29; RCW, 26) with diabetes mellitus, peripheral neuropathy, and a Wagner grade 1 or 2 neuropathic plantar ulcer. Each participant wore an activity monitor for 14 consecutive days. Step activity and healing variables were assessed using independent t tests, Kruskal-Wallis, Kaplan-Meier, and Mantel-Cox log-rank tests.

RESULTS

Mean participant age was 55 (SD, 11) years. The percentage of ulcers healed was lower in the RCW group versus the TCC group (65% vs 93%). If healed, average healing rate was 77 (SD, 48) days in the TCC group and 138 (SD, 143) days in the RCW group. Survival distribution by ulcer location was different for RCW forefoot than other locations (132 ± 13 days vs 91 ± 15, 75 ± 11, and 102 ± 36 days for TCC forefoot, TCC-midfoot/hindfoot, and RCW-midfoot/hindfoot, respectively; χ2 = 10.69, P = .014). Average step count was 2,597 in the RCW group versus 1,813 steps in the TCC group (P = .07). The daily peak mean cadence for 20-, 30-, or 60-minute periods was greater with RCW use.

CONCLUSIONS

Step activity in participants with RCWs was increased compared with those with TCCs. Because of their potential to be easily removable, RCWs may impair ulcer healing by allowing greater step activity.

Therapeutics of Charcot neuroarthropathy and pharmacological mechanisms: A bone metabolism perspective

Charcot neuroarthropathy (CN) is a chronic, destructive, and painless damage of the skeletal system that affects the life quality of patients. CN, with an unclear mechanism, is characterized with invasive destruction of bones and a serious abnormality of bone metabolism. Unfortunately, development of an effective prevention and treatment strategy for CN is still a great challenge. Of note, recent studies providing an insight into the molecular mechanisms of bone metabolism and homeostasis have propelled development of novel CN therapeutic strategies. Therefore, this review aims to shed light on the pathogenesis, diagnosis, and treatment of CN. In particular, we highlight the eminent role of the osteoprotegerin (OPG)-receptor activator of nuclear factor-κB (RANK)-RANK ligand (RANKL) system in the development of CN. Furthermore, we summarize and discuss the diagnostic biomarkers of CN as well as the potential pharmacological mechanisms of current treatment regimens from the perspective of bone metabolism. We believe that this review will enhance the current state of knowledge on the diagnosis, prevention, and therapeutic efficacy of CN.

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.

Novel Biomarkers Predictive of Diabetic Charcot Foot-An Overview of the Literature

Background: Although Charcot diabetic foot (CDF) is a frequent complication of diabetic neuropathy, less is known about the possibility of its early prevention. Methods: A review of the original articles published in English, using the "biomarkers AND Charcot's foot" criterion, resulted in 33 articles from the PubMed database and seven articles from the Web of Science database. The five duplicates were eliminated, and two independent reviewers selected the most relevant articles, leaving a total of 21 articles. Results: The biomarkers identified are exhaustively described, related to the system of advanced glycation end products (AGEs) and their soluble receptors (sRAGE), inflammatory cascade, osteoclastogenesis, and, respectively, osteoblastic activity. Conclusions: This article highlights the importance of potential early identifiable biomarkers that can lead to microstructural changes in the affected bones.

Fractures and Osteoporosis in Patients With Diabetes With Charcot Foot

OBJECTIVE

Charcot foot is a serious complication of diabetes, with degeneration of the bones and joints in the foot and ankle. It is unknown whether patients with diabetes with a Charcot foot have an increased risk of osteoporosis and fractures. The aim of this study was to investigate whether patients with diabetes with a Charcot foot have an increased risk of fracture and/or osteoporosis compared with patients with diabetes without Charcot foot.

RESEARCH DESIGN AND METHODS

A Danish register-based, nationwide population-based matched cohort study was conducted. During 1995-2018, we identified 1,602 patients with diabetes with Charcot foot and matched them on sex and date of diagnosis of diabetes with 16,296 patients with diabetes without Charcot foot. We used logistic regression to estimate odds ratios (ORs) with 95% CIs for fracture and osteoporosis. Information about exposure, outcome, and comorbidities was retrieved from the Danish National Patient Register.

RESULTS

Diabetes patients with Charcot foot had higher risk of fractures compared with those without Charcot foot (i.e., ORs for any fracture, lower-leg fracture, foot fracture, and osteoporotic fracture were 1.8 [95% CI 1.6-2.0], 2.4 [2.0-2.8], 2.9 [2.6-3.3], and 1.3 [1.1-1.4], respectively). Furthermore, patients with diabetes with Charcot foot had higher risk of osteoporosis compared with the patients without Charcot foot, with an OR of 1.3 (95% CI 1.1-1.5).

CONCLUSIONS

Patients with diabetes with a Charcot foot have an increased risk of fractures and osteoporosis compared with patients with diabetes without a Charcot foot.

Multi-System Factors Associated with Metatarsophalangeal Joint Deformity in Individuals with Type 2 Diabetes

The underlying factors contributing to metatarsophalangeal joint deformity, a known precursor to skin breakdown in individuals with diabetes mellitus (DM), is likely to involve multiple body systems. The purpose of this cross-sectional study was to identify multi-system factors associated with metatarsophalangeal joint deformity in individuals with type 2 DM and peripheral neuropathy (n = 60). Metatarsophalangeal joint deformity was quantified with a computed tomography (CT) scan. System biomarkers included the musculoskeletal system (foot intrinsic muscle deterioration, tarsal/metatarsal bone mineral density, ankle dorsiflexion, metatarsophalangeal extension movement during a sit to stand task); the vascular system (ankle-brachial index); and the endocrine/immune systems (high sensitivity C-reactive protein, skin intrinsic fluorescence, and hemoglobin A1C). Muscle deterioration (r = 0.27), bone density (r = -0.35), metatarsophalangeal extension movement (r = 0.50), maximum dorsiflexion (r = -0.31), and ankle-brachial index (r = 0.33) were related to metatarsophalangeal joint deformity (p < 0.05). Bone mineral density and metatarsophalangeal extension movement were retained in a regression model relating to deformity (R2 = 0.34). All musculoskeletal system biomarkers and the ankle-brachial index demonstrated weak to moderate relationships to metatarsophalangeal joint deformity. Bone mineral density of the tarsal/metatarsal bones and extending the toes during a sit to stand task were the two strongest factors associated with metatarsophalangeal joint deformity. Evaluation and management of foot bone mineral density and toe extension movement pattern could reduce metatarsophalangeal joint deformity and the risk of skin breakdown and subsequent amputation.

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.

Charcot Neuroarthropathy Advances: Understanding Pathogenesis and Medical and Surgical Management

Understanding new theories of the epidemiology of Charcot neuroarthropathy is practice changing. Treatment of Charcot neuroarthropathy is evolving from a passive approach to one that sees the urgency of proactive, early recognition, thereby avoiding the cascading events that lead to the complex, limb-threatening deformities. Preventive medicine is the most efficient at avoiding severe deformity, with prolonged offloading and immobilization as the current mainstay of treatment. However, with recent advancements in medical and surgical modalities, this may become the treatment of the past as clinicians begin to favor medical management and early surgical intervention.

Clinical Outcomes and Complications of Midfoot Charcot Reconstruction With Intramedullary Beaming

BACKGROUND:

The purpose of this study was to examine the clinical outcomes and complications of patients with midfoot Charcot managed with midfoot osteotomy, realignment arthrodesis, and stabilization using intramedullary beams.

METHODS:

Consecutive patients with midfoot Charcot treated at a tertiary-care foot and ankle center from January 2013 to July 2016 who underwent corrective osteotomy with internal beam fixation were identified; 25 patients were included in the final analysis. Patients with a minimum 1-year follow-up were evaluated with physical examination, weightbearing radiographs, and patient-reported outcome measures. The primary outcome measure was defined as restoration of a stable, plantigrade, ulcer-free foot. Median age was 58 years, median BMI was 32, and 80% were diabetic (75% insulin-dependent).

RESULTS:

An ulcer-free, stable, plantigrade foot was obtained in 84% of patients. The radiographic lateral and anteroposterior Meary angle medians improved 9° and 15°, respectively, from preoperative to final postoperative weightbearing measurements ( P < .001 and P = .02). Overall, 46% of midfoot osteotomies were united on final radiographs at a median 18-month radiographic follow-up. Deep infection developed in 6 (24%) patients. The presence of a preoperative ulcer was found to be predictive of postoperative infection (P = .04); all 6 deep infections occurred in patients with preoperative ulceration. Four (16%) patients progressed to amputation at a mean 15 postoperative months, all for deep infection.

CONCLUSION:

Midfoot Charcot reconstruction with intramedullary beaming allowed for restoration of an ulcer-free, plantigrade foot in most patients, but the complication rates were high, especially in patients with preoperative ulceration.

LEVEL OF EVIDENCE:

Level IV, retrospective case series.

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.

A review of bone metabolism and developments in medical treatment of the diabetic Charcot foot

Charcot foot is a rare but severe, and possibly limb-threatening, complication to neuropathy and diabetes mellitus. The current treatment consists of long-term off-loading, and has a large negative impact on the patient's life. Much research has gone into understanding the condition and its biochemical mechanisms, however, the underlying pathogenesis of a Charcot foot is not yet fully understood. In the recent decades several key advances in our understanding of the Charcot foot have been made, both in regards to the changes in bone metabolism and structure an acute Charcot foot can cause, and to the molecular pathways involved in this. This review summerizes the available research into the bone metabolism around a Charcot foot, with an emphasis on the biochemical profile. The existing data regarding attempts at medical treatment is also reviewed, including novel trials targetting specific inflammatory pathways upregulated in the acute diabetic Charcot foot.

Immobilization-induced osteolysis and recovery in neuropathic foot impairments

BACKGROUND

Neuropathic foot impairments treated with immobilization and off-loading result in osteolysis. In order to prescribe and optimize rehabilitation programs after immobilization we need to understand the magnitude of pedal osteolysis after immobilization and the time course for recovery.

OBJECTIVE

To determine differences in a) foot skin temperature; b) calcaneal bone mineral density (BMD) after immobilization; c) calcaneal BMD after 33-53weeks of recovery; and d) percent of feet classified as osteopenic or osteoporotic after recovery in participants with neuropathic plantar ulcers (NPU) compared to Charcot neuroarthropathy (CNA).

METHODS

Fifty-five participants with peripheral neuropathy were studied. Twenty-eight participants had NPU and 27 participants had CNA. Bilateral foot skin temperature was assessed before immobilization and bilateral calcaneal BMD was assessed before immobilization, after immobilization and after recovery using quantitative ultrasonometry.

RESULTS

Before immobilization, skin temperature differences in CNA between their index and contralateral foot were markedly higher than NPU feet (3.0 degree C versus 0.7 degree C, respectively, p<0.01); BMD in NPU immobilized feet averaged 486±136mg/cm², and CNA immobilized feet averaged 456±138mg/cm², p>0.05). After immobilization, index NPU feet lost 27mg/cm²; CNA feet lost 47mg/cm² of BMD, p<0.05. After recovery, 61% of NPU index feet and 84% of CNA index feet were classified as osteopenic or osteoporotic.

CONCLUSIONS

There was a greater osteolysis after immobilization with an attenuated recovery in CNA feet compared to NPU feet. The attenuated recovery of pedal BMD in CNA feet resulted in a greater percentage of feet classified as osteoporotic and osteopenic.

Pathogenesis and potential relative risk factors of diabetic neuropathic osteoarthropathy

Diabetic neuropathic osteoarthropathy (DNOAP) is an uncommon, but with considerable morbidity and mortality rates, complication of diabetes. The real pathogenesis is still unclear. The two popular theories are the neuro-vascular theory and neuro-traumatic theory. Most theories and pathways focused on the uncontrolled inflammations that resulted in the final common pathway, receptor activator of nuclear factor κβ ligand (RANKL)/osteoprotegerin (OPG) axis, for the decreased bone density in DNOAP with an osteoclast and osteoblast imbalance. However, the RANKL/OPG pathway does not explain all the changes, other pathways and factors also play roles. A lot of DNOAP potential relative risk factors were evaluated and reported in the literature, including age, gender, weight, duration and type of diabetes, bone mineral density, peripheral neuropathy and arterial disease, trauma history, and some others. However, most of them are still in debates. Future studies focus on the pathogenesis of DNOAP are still needed, especially for the genetic factors. And, the relationship between DNOAP and those potential relative risk factors are still need to further clarify.