The Charcot joint: a modern neurologic perspective

Charcot neuro-osteoarthropathy: a review of key concepts and an evidence-based surgical management algorithm

Charcot neuro-osteoarthropathy (CNO), mainly as a result of diabetic neuropathy, is a complex problem which carries significant morbidity, and is an increasing burden on healthcare as demographics change globally. A multi-disciplinary team (MDT) is necessary to treat the multiple facets of this disease. The multifactorial and non-homogenous nature of this condition and its management, has prevented the development of comprehensive guidelines based on level 1 evidence. Although there is a trend to surgically treat these patients in tertiary centres, the increasing prevalence of CNO necessitates the capability of all units to manage this condition to an extent locally. This article conducted a thorough literature search of Pubmed and Embase from 2003 to 2023 including the following search terms; "Charcot" "neuroarthropathy" "diabetic foot" "management" "surgery" "treatment" "reconstruction". The results of this review have been summarised and synthesised into an evidence-based algorithm to aid in the surgical decision-making process, and improve the understanding of surgical management by the whole MDT.

Cutaneous Wound Healing and the Effects of Cannabidiol

Cutaneous wounds, both acute and chronic, begin with loss of the integrity, and thus barrier function, of the skin. Surgery and trauma produce acute wounds. There are 22 million surgical procedures per year in the United States alone, based on data from the American College of Surgeons, resulting in a prevalence of 6.67%. Acute traumatic wounds requiring repair total 8 million per year, 2.42% or 24.2 per 1000. The cost of wound care is increasing; it approached USD 100 billion for just Medicare in 2018. This burden for wound care will continue to rise with population aging, the increase in metabolic syndrome, and more elective surgeries. To heal a wound, an orchestrated, evolutionarily conserved, and complex series of events involving cellular and molecular agents at the local and systemic levels are necessary. The principal factors of this important function include elements from the neurological, cardiovascular, immune, nutritional, and endocrine systems. The objectives of this review are to provide clinicians engaged in wound care and basic science researchers interested in wound healing with an updated synopsis from recent publications. We also present data from our primary investigations, testing the hypothesis that cannabidiol can alter cutaneous wound healing and documenting their effects in wild type (C57/BL6) and db/db mice (Type 2 Diabetes Mellitus, T2DM). The focus is on the potential roles of the endocannabinoid system, cannabidiol, and the important immune-regulatory wound cytokine IL-33, a member of the IL-1 family, and connective tissue growth factor, CTGF, due to their roles in both normal and abnormal wound healing. We found an initial delay in the rate of wound closure in B6 mice with CBD, but this difference disappeared with time. CBD decreased IL-33 + cells in B6 by 70% while nearly increasing CTGF + cells in db/db mice by two folds from 18.6% to 38.8% (p < 0.05) using a dorsal wound model. We review the current literature on normal and abnormal wound healing, and document effects of CBD in B6 and db/db dorsal cutaneous wounds. CBD may have some beneficial effects in diabetic wounds. We applied 6-mm circular punch to create standard size full-thickness dorsal wounds in B6 and db/db mice. The experimental group received CBD while the control group got only vehicle. The outcome measures were rate of wound closure, wound cells expressing IL-33 and CTGF, and ILC profiles. In B6, the initial rate of wound closure was slower but there was no delay in the time to final closure, and cells expressing IL-33 was significantly reduced. CTGF + cells were higher in db/bd wounds treated with CBD. These data support the potential use of CBD to improve diabetic cutaneous wound healing.

Rotating Hinge Knee Arthroplasty for Charcot Joints of the Knees in Patients With Charcot-Marie-Tooth Disease: A Report of Two Cases

We report two cases wherein rotating hinge knee (RHK) arthroplasty was performed for Charcot joints that developed secondary to Charcot-Marie-Tooth disease (CMT).  Case 1 was of a 74-year-old woman with CMT. She presented with muscle weakness and sensory disturbances of the distal lower limbs, deformity, and significant medial instability of the bilateral knees. She was then diagnosed with Charcot joints of the knees secondary to CMT, which were treated with RHK arthroplasty. Five years postoperatively, there was no instability, and she was able to stand unassisted without pain. Case 2 was a 90-year-old woman with CMT who presented with muscle weakness and sensory disturbances of the distal lower limbs, deformity, and significant medial instability of the bilateral knees. She was then diagnosed with Charcot joints of the knees secondary to CMT, which were also treated with RHK arthroplasty. One year postoperatively, there was no instability, and she was able to walk smoothly using a walker. These clinical cases indicate that RHK arthroplasty can be a good therapeutic option for Charcot joints of the knees in patients with CMT.

The Differentiation Between Infection and Acute Charcot

The differentiation between acute Charcot neuroarthropathy and infection in the foot and ankle should be supported by multiple criteria. A detailed history and physical examination should always be completed. Plain radiographs should be performed, though advanced imaging, currently MRI, is more helpful in diagnosis. Scintigraphy and PET may become the standard imaging modalities once they are more clinically available due to their reported increased accuracy. Laboratory analysis can also act as a helpful diagnostic tool. Histopathology with culturing should be performed if osteomyelitis is suspected. The prompt diagnosis and initiation of treatment is vital to reducing patient morbidity and mortality.

Establishment of a Neurodegenerative Charcot Mouse Model

BACKGROUND

This study aimed to mimic the changes from Charcot neuropathic arthropathy in humans by examining the effects of exposing diet-induced obese (DIO) mice to neurotrauma through a regimented running protocol.

METHODS

Forty-eight male wild-type C57BL/6J mice were obtained at age 6 weeks and separated into 2 groups for diet assignment. After a 1-week acclimation period, half of the mice consumed a high-fat diet (60% fat by kcal) ad libitum to facilitate neuropathic diet-induced obesity whereas the other half were control mice and consumed an age-matched standard low-fat control diet (10% fat by kcal). At age 12 weeks, half of the animals from each group were subjected to a high-intensity inclined treadmill running protocol, which has been previously demonstrated to induce neurotrauma. Sensory testing and radiographic analyses were periodically performed. Histopathologic analyses were performed post killing.

RESULTS

DIO mice had significantly higher bodyweights, higher body fat percentages, and lower bone mineral density than wildtype control mice that were fed a normal diet throughout the experiment (P < .001 for each). DIO mice displayed significantly reduced sensory function in week 1 (P = .005) and this worsened over time, requiring 20.6% more force for paw withdrawal by week 10 (P < .001). DIO mice that ran demonstrated greater midfoot subluxation and tarsal instability over all time points compared with normal-diet mice that ran (P < .001). Histopathologic analyses revealed that DIO mice that ran demonstrated significant changes compared with controls that ran (P < .001 for each parameter).

CONCLUSION

Changes akin to the earliest changes observed in or before joint destruction identified in diabetic Charcot neuropathic arthropathy in humans were observed.

CLINICAL RELEVANCE

There is currently no standard of treatment for patients with Charcot neuropathic arthropathy. This study establishes a protocol for an animal model that can be used to study and compare interventions to treat this disease.

Anti-NGF treatment worsens subchondral bone and cartilage measures while improving symptoms in floor-housed rabbits with osteoarthritis

Objective: Osteoarthritis (OA) is a common joint disorder often affecting the knee. It is characterized by alterations of various joint tissues including subchondral bone and by chronic pain. Anti-nerve growth factor (NGF) antibodies have demonstrated improvement in pain associated with OA in phase 3 clinical trials but have not been approved due to an increased risk of developing rapidly progressive OA. The aim of this study was to investigate effects of systemic anti-NGF-treatment on structure and symptoms in rabbits with surgically induced joint instability. Methods: This was elicited by anterior cruciate ligament transection and partial resection of the medial meniscus in right knee of 63 female rabbits, housed altogether in a 56 m² floor husbandry. Rabbits received either 0.1, 1 or 3 mg/kg anti-NGF antibody intra-venously at weeks 1, 5 and 14 after surgery or vehicle. During in-life phase, static incapacitance tests were performed and joint diameter was measured. Following necropsy, gross morphological scoring and micro-computed tomography analysis of subchondral bone and cartilage were performed. Results: After surgery, rabbits unloaded operated joints, which was improved with 0.3 and 3 mg/kg anti-NGF compared to vehicle injection during the first half of the study. The diameter of operated knee joints increased over contralateral measures. This increase was bigger in anti-NGF treated rabbits beginning 2 weeks after the first IV injection and became dose-dependent and more pronounced with time. In the 3 mg/kg anti-NGF group, the bone volume fraction and trabecular thickness increased in the medio-femoral region of operated joints compared to contralateral and to vehicle-treated animals, while cartilage volume and to a lesser extent thickness decreased. Enlarged bony areas were found in right medio-femoral cartilage surfaces of animals receiving 1 and 3 mg/kg anti-NGF. Alterations of all structural parameters were particularly distinct in a subgroup of three rabbits, which also exhibited more prominent symptomatic improvement. Conclusion: This study showed that anti-NGF administration exerted negative impact on structure in destabilized joints of rabbits, while pain-induced unloading of joints was improved. Our findings open up the possibility to better understand the effects of systemic anti-NGF, particularly on subchondral bone, and thus the occurrence of rapidly progressive OA in patients.

Role of imaging for eligibility and safety of a-NGF clinical trials

Nerve growth factor (a-NGF) inhibitors have been developed for pain treatment including symptomatic osteoarthritis (OA) and have proven analgesic efficacy and improvement in functional outcomes in patients with OA. However, despite initial promising data, a-NGF clinical trials focusing on OA treatment had been suspended in 2010. Reasons were based on concerns regarding accelerated OA progression but were resumed in 2015 including detailed safety mitigation based on imaging. In 2021, an FDA advisory committee voted against approving tanezumab (one of the a-NGF compounds being evaluated) and declared that the risk evaluation and mitigation strategy was not sufficient to mitigate potential safety risks. Future clinical trials evaluating the efficacy of a-NGF or comparable molecules will need to define strict eligibility criteria and will have to include strategies to monitor safety closely. While disease-modifying effects are not the focus of a-NGF treatments, imaging plays an important role to evaluate eligibility of potential participants and to monitor safety during the course of these studies. Aim is to identify subjects with on-going safety findings at the time of inclusion, define those potential participants that are at increased risk for accelerated OA progression and to withdraw subjects from on-going studies in a timely fashion that exhibit imaging-confirmed structural safety events such as rapid progressive OA. OA efficacy- and a-NGF studies apply imaging for different purposes. In OA efficacy trials image acquisition and evaluation aims at maximizing sensitivity in order to capture structural effects between treated and non-treated participants in longitudinal fashion. In contrast, the aim of imaging in a-NGF trials is to enable detection of structural tissue alterations that either increase the risk of a negative outcome (eligibility) or may result in termination of treatment (safety).

Cartilage Damage Pathological Characteristics of Diabetic Neuropathic Osteoarthropathy

Background

Diabetic neuropathic osteoarthropathy (DNOAP) is a rare and easily missed complication for diabetes that leads to increased morbidity and mortality. DNOAP is characterized by progressive destruction of bone and joint, but its pathogenesis remains elusive. We herein aimed to investigate the pathological features and pathogenesis of the cartilages damage in DNOAP patients.

Methods

The articular cartilages of eight patients with DNOAP and eight normal controls were included. Masson staining and safranine O/fixed green staining (S-O) were used to observe the histopathological characteristics of cartilage. The ultrastructure and morphology of chondrocytes were detected by electron microscopy and toluidine blue staining. Chondrocytes were isolated from DNOAP group and control group. The expression of receptor activator of nuclear factor kappaB ligand (RANKL), osteoprotegerin (OPG), interleukin-1 beta (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and Aggrecan protein was evaluated by western blot. Reactive oxygen species (ROS) levels were measured using a 2',7'-dichlorofluorescin diacetate (DCFH-DA) probe. The percentage of apoptotic cells was determined by flow cytometry (FCM). The chondrocytes were cultured with different glucose concentrations to observe the expression of RANKL and OPG.

Results

Compared with the control group, the DNOAP group showed fewer chondrocytes, subchondral bone hyperplasia, and structural disorder, and a large number of osteoclasts formed in the subchondral bone area. Moreover, mitochondrial and endoplasmic reticulum swellings were observed in the DNOAP chondrocytes. The chromatin was partially broken and concentrated at the edge of nuclear membrane. The ROS fluorescence intensity of chondrocyte in DNOAP group was higher than that in normal control group (28.1 ± 2.3 vs. 11.9 ± 0.7; P < 0.05). The expression of RANKL, TNF-α, IL-1β, and IL-6 protein in DNOAP group was higher than that in normal control group, whereas OPG and Aggrecan protein were lower than that in normal control group (both P < 0.05). FCM showed that the apoptotic rate of chondrocyte in DNOAP group was higher than that in normal control group (P < 0.05). The RANKL/OPG ratio showed significant upward trend when the concentration of glucose was over than 15 mM.

Conclusions

DNOAP patients tend to have severe destruction of articular cartilage and collapse of organelle structure including mitochondrion and endoplasm reticulum. Indicators of bone metabolism (RANKL and OPG) and inflammatory cytokines (IL-1β, IL-6, and TNF-α) play an important role in promoting the pathogenesis of DNOAP. The glucose concentration higher than 15 mM made the RANKL/OPG ratio change rapidly.

High rate of complications after corrective midfoot/subtalar arthrodesis and Achilles tendon lengthening in Charcot arthropathy type Sanders 2 and 3

PURPOSE

Corrective midfoot resection arthrodesis is the standard treatment of Charcot arthropathy type Sanders 2 and 3 with severe dislocation. In order to critically evaluate the effect of surgical correction, a retrospective analysis of our patient cohort was performed. Hereby, special emphasis was set on the analysis of the pre- and post-operative equinus position of the hindfoot.

METHODS

Retrospectively, all patients (n = 82) after midfoot resection arthrodesis in Charcot type Sanders 2 or 3 were included. Complications were recorded, and the mean complication-free interval was calculated. Additionally, the calcaneal pitch as well as Meary's angle were measured pre- and post-operatively and in case of complications.

RESULTS

Overall complication rate was 89%. Revision surgery was necessary in 46% of all patients. The mean complication-free interval was 285 days (0-1560 days). Calcaneal pitch and Meary's angle significantly improved after operation but returned to pre-operative values after onset of complications. Achilles tendon lengthening showed no significant effects on the mean complication-free interval.

CONCLUSION

Operative treatment of Charcot arthropathy remains a surgical challenge with high complication rates. Surgical correction of equinus position has been highlighted for successful treatment but was not able to prevent complications in this study, which is demonstrated by the recurrent decrease of the calcaneal pitch in cases of reoperation. Therefore, as a conclusion of our results, our treatment algorithm changed towards primarily addressing the equinus malpositioning of the hindfoot by corrective arthrodesis of the hindfoot.

Etiology, Epidemiology, and Outcomes of Managing Charcot Arthropathy

Surgical intervention for Charcot arthropathy is becoming more common; this is driven by an increased prevalence, better understanding of the cause, identifying patient risk factors that influence outcomes, and how to best optimize these. This article aims to summarize the cause of Charcot, look at the factors that influence the outcomes, and the financial cost of managing what is a very challenging condition.

Cervical spondylotic myelopathy with syringomyelia presenting as hip Charcot neuroarthropathy: A case report and review of literature

BACKGROUND

Charcot neuroarthropathy (CN) is a systemic disease characterized by progressive bone loss and destruction, which is usually closely related to diabetes, HIV, etc. However, CN caused by syringomyelia accounts for only 5% of CN cases; the shoulder and elbow are most often involved, and the hip joint is rarely affected. As a rare factor, cervical spondylotic myelopathy (CSM) can be associated with syringomyelia, which is scarcely reported in the literature. Here, we present the first case report to date of CN of the hip caused by syringomyelia secondary to CSM.

CASE SUMMARY

We describe a 76-year-old male patient who was diagnosed with CSM due to neck pain and weakness of limbs 16 years ago. Four years ago, he noticed recurrent swelling of the right hip with pain and was diagnosed with degenerative arthritis. Recently, however, his symptoms gradually worsened, and because of progressive pain, destabilization and weakness of the right hip, he was admitted to our hospital. Through systematic physical, radiographic and laboratory examinations, we finally reached a diagnosis: CN of the right hip associated with syringomyelia secondary to CSM. After comprehensive evaluation of the patient's condition, we performed right total hip arthroplasty. During the follow-up, the patient felt well clinically and could walk independently with a knee brace.

CONCLUSION

We suggest a possible etiological association between CSM and syringomyelia, which may reflect a potential pathogenesis of CN. We encourage clinicians to actively carry out a detailed medical history and comprehensive physical and imaging examinations in patients with joint lesions, especially chronic shoulder neck pain, to rule out the possibility of this association, which plays a crucial role in the early diagnosis of CN. Arthroplasty may no longer be an absolute contraindication to surgical treatment of CN. Reasonable selection of the surgical strategy can markedly improve the clinical symptoms and quality of life of patients.

Neuropathic (Charcot) Arthropathy of the Knee

Neuropathic arthropathy of the knee (Charcot knee) is a rare pathology defined by progressive destruction of bone and soft tissue in a patient with underlying peripheral neuropathy. Historically, Charcot knee was associated with neurosyphilis, but it has been increasingly described as a late stage of diabetes. The pathophysiology of the disease is not completely understood, but theories include repetitive microtrauma and an abnormal neurovascular response. Patients present with a warm, swollen, and unstable joint and have rapid bone resorption and characteristic findings on pathology. Nonsurgical options for pain and dysfunction include total contact casting and bracing treatment. Pharmacologic management includes diphosphonates, although this use is considered off-label. Surgical management historically included knee fusion. However, recent case series have suggested that newer prostheses allow for successful arthroplasty in this cohort, although complications are higher when compared with joint arthroplasty in patients with normal neurologic function.

Nerve Growth Factor (NGF) Inhibitors and Related Agents for Chronic Musculoskeletal Pain: A Comprehensive Review

Musculoskeletal pain such as osteoarthritis (OA) and low back pain (LBP) are very common and contribute to enormous burden and societal costs, despite dramatic therapeutic advances over recent decades. Novel approaches and targeted therapies are required to satisfy the urgent unmet medical need of musculoskeletal pain relief in both conditions. Nerve growth factor (NGF) inhibitors have utilized novel mechanisms different from conventional drugs, which have a variety of gastrointestinal, cardiac, or renal adverse effects. Several phase 2/3 studies have been accomplished for these drugs, such as tanezumab, fasinumab, and tyrosine receptor kinase A (TrkA) inhibitors. We searched the literature using the PubMed database and clinical trials using ClinicalTrials.gov to identify original papers, meta-analyses as well as ongoing clinical trials assessing the efficacy and safety profile of these drugs. In this narrative review, we briefly overview the disease burden of musculoskeletal pain, the role of NGF signaling and its receptors in the genesis of pain, and the mechanisms of action of inhibitors of NGF signaling and downstream pathways, and then discuss the efficacy and safety of each investigational drug in OA and LBP. Finally, we briefly review two serious adverse effects of NGF inhibitors, namely rapidly progressive OA and sympathetic system effects, and conclude with possible barriers and potential research directions to overcome these.

Charcot Reconstruction: Outcomes in Patients With and Without Diabetes

The objective of this study is to compare risk adjusted matched cohorts of Charcot neuroarthropathy patients who underwent osseous reconstruction with and without diabetes. The 2 groups were matched based on age, body mass index, hypertension, history of end-stage renal disease, and peripheral arterial disease. Bivariate analysis was performed for preoperative infection, location of Charcot breakdown, and post reconstruction outcomes, in patients with a minimum of 1 year follow-up period. Through bivariate analysis, presence of preoperative ulceration (p = .0499) was found to be statistically more likely in the patients with diabetes; whereas, delayed osseous union (p = .0050) and return to ambulation (p ≤ .0001) was statistically more likely in patients without diabetes. The nondiabetic Charcot patients were 17.6 folds more likely to return to ambulation (odds ratio [OR] 17.6 [95% confidence interval {CI} {3.5-87.6}]), and 16.4 folds more likely to have delayed union (OR 16.4 [95% CI {1.9-139.6)]). Subanalysis compared well-controlled diabetic and nondiabetic Charcot neuroarthropathy patients for same factors. Multivariate analysis, in the subanalysis, found return to ambulation was 15.1 times likely to occur in the nondiabetic CN cohort (OR 15.1 [95% CI 1.3-175.8]) compared to the well-controlled diabetic CN cohort.

Foot ulcer recurrence, plantar pressure and footwear adherence in people with diabetes and Charcot midfoot deformity: A cohort analysis

AIMS

To investigate people with Charcot midfoot deformity with regard to plantar pressure, footwear adherence and plantar foot ulcer recurrence.

METHODS

Twenty people with diabetes, Charcot midfoot deformity, plantar foot ulcer history and custom-made footwear were assessed with regard to barefoot and in-shoe plantar pressures during walking, footwear adherence (% of daily steps over 7-day period) and plantar foot ulcer recurrence over 18 months. In a cohort design, they were compared to 118 people without Charcot foot (non-Charcot foot group) with custom-made footwear and similar ulcer risk factors.

RESULTS

Median (interquartile range) barefoot midfoot peak pressures were significantly higher in the Charcot foot group than in the non-Charcot foot group [756 (260-1267) vs 146 (100-208) kPa; P<0.001]. In-shoe midfoot peak pressures were not significantly higher in the Charcot foot group [median (interquartile range) 152 (104-201) vs 119 (94-160) kPa] and significantly lower for all other foot regions. Participants in the Charcot foot group were significantly more adherent, especially at home, than participants in the non-Charcot foot group [median (interquartile range) 94.4 (85.4-95.0)% vs. 64.3 (25.4-85.7)%; P=0.001]. Ulcers recurred in 40% of the Charcot foot group and in 47% of the non-Charcot foot group (P=0.63); midfoot ulcers recurred significantly more in the Charcot foot group (4/8) than in the non-Charcot foot group (1/55; P=0.001).

CONCLUSIONS

Effective offloading and very high footwear adherence were found in people with diabetes and Charcot midfoot deformity. While this may help protect against plantar foot ulcer recurrence, a large proportion of such people still experience ulcer recurrence. Further improvements in adherence and custom-made footwear design may be required to improve clinical outcome.

Free tensor fascia lata true-perforator flap transfer for reconstruction of the calcaneal soft tissue defect complicated with osteomyelitis in a patient with alcohol-induced Charcot foot: A case report and literature review

Charcot foot is can result in bone deformities and soft tissue defects. We report a case of alcohol-induced Charcot (AIC) foot with soft tissue defect including the weight-bearing zone of the heel and osteomyelitis, which was successfully reconstructed with free tensor fascia lata true-perforator flap (TFLtp). A 56-year-old male suffered from AIC foot with an 18 × 6 cm defect. Based on the preoperative ultrasound, we identified the overlying upper thigh area offering one of the thickest dermis. A TFLtp flap was raised sparing the TFL muscle based on one perforator without including the main trunk of the transverse/ascending branch of the lateral femoral circumflex vessel. The TFLtp flap was transferred to the heel and anastomosed to the posterior tibial artery in an end-to-side fashion. The patient complained no postoperative discomfort of the donor site and was able to walk on his foot after 5 weeks. This case report highlights that the TFLtp flap may offer thick dermis, faster surgery due to perforator level dissection and a concealed donor site.

A comprehensive review of the treatment and management of Charcot spine

Charcot spine arthropathy (CSA), a result of reduced afferent innervation, is an occurrence of Charcot joint, a progressive, degenerative disorder in vertebral joints, related mostly to spinal cord injury. The repeated microtrauma is a result of a lack of muscle protection and destroys cartilage, ligaments, and disc spaces, leading to vertebrae destruction, joint instability, subluxation, and dislocation. Joint destruction compresses nerve roots, resulting in pain, paresthesia, sensory loss, dysautonomia, and spasticity. CSA presents with back pain, spinal deformity and instability, and audible spine noises during movement. Autonomic dysfunction includes bowel and bladder dysfunction. It is slowly progressive and usually diagnosed at a late stage, usually, on average, 20 years after the first initial insult. Diagnosis is rarely clinical related to the nature of nonspecific symptoms and requires imaging with computed tomography (CT) and magnetic resonance imaging (MRI). Conservative management focuses on the prevention of fractures and the progression of deformities. This includes bed rest, orthoses, and braces. These could be useful in elderly or frail patients who are not candidates for surgical treatment, or in minimally symptomatic patients, such as patients with spontaneous fusion leading to a stable spine. Symptomatic treatment is offered for autonomic dysfunction, such as anticholinergics for bladder control. Most patients require surgical treatment. Spinal fusion is achieved with open, minimally-open (MOA) or minimally-invasive (MIS) approaches. The gold standard is open circumferential fusion; data is lacking to determine the superiority of open or MIS approaches. Patients usually improve after surgery; however, the rarity of the condition makes it difficult to estimate outcomes. This is a review of the latest and seminal literature about the treatment and chronic management of Charcot spine. The review includes the background of the syndrome, clinical presentation, and diagnosis, and compares the different treatment options that are currently available.

Characteristics of Patients with Charcot's Arthropathy and its Complications in the Saudi Diabetic Population: A Cross-Sectional Study

BACKGROUND

Charcot's arthropathy (CA) is a destructive rare complication of diabetes, and its diagnosis remains challenging for foot specialists and surgeons. We aimed to assess the clinical presentation and characteristics of CA and the frequencies of its various types.

METHODS

This cross-sectional study was conducted from January 1, 2007, to December 31, 2016, and included 149 adults with diabetes diagnosed as having CA. Cases of CA were classified based on the Brodsky anatomical classification into five types according to location and involved joints.

RESULTS

The mean ± SD age of the studied cohort was 56.7 ± 11 years, with a mean ± SD diabetes duration of 21.2 ± 7.0 years. The CA cohort had poorly controlled diabetes and a high rate of neuropathy and retinopathy. The most frequent type of CA was type 4, with multiple regions involved at a rate of 56.4%, followed by type 1, with midfoot involvement at 34.5%. A total of 47.7% of the patients had bilateral CA. Complications affected 220 limbs, of which 67.7% had foot ulceration. With respect to foot deformity, hammertoe affected all of the patients; hallux valgus, 59.5%; and flatfoot, 21.8%.

CONCLUSIONS

There is a high rate of bilateral CA, mainly type 4, which could be attributed to cultural habits in Saudi Arabia, including footwear. This finding warrants increasing awareness of the importance of maintaining proper footwear to avoid such complications. Implementation of preventive measures for CA is urgently needed.

NGF increases FGF2 expression and promotes endothelial cell migration and tube formation through PI3K/Akt and ERK/MAPK pathways in human chondrocytes

OBJECTIVE

Vascular invasion is observed at the osteochondral junction in osteoarthritis (OA). Nerve growth factor (NGF) as an angiogenic factor is expressed in OA. This study is to investigate the effects of NGF on angiogenesis in vitro in human chondrocytes.

DESIGN

Articular cartilages of knee joints were harvested from healthy and OA patients. Expressions of NGF and tropomyosin-related kinase A (TrkA) were detected by western blot, Safranin-O and fast green staining and immunohistochemistry in cartilage. Expression of fibroblast growth factor 2 (FGF2) was detected by western blot in cultured chondrocytes. Chondrocytes were transfected by lentiviral vectors to knock down TrkA. Migration and tube formation of human microvascular endothelial cell (HMVEC) were assessed by using transwell co-culture with chondrocyte after treatment of NGF.

RESULTS

We confirmed expressions of NGF and TrkA were significantly up-regulated in OA. NGF induced expression of FGF2 in a time- and dose-dependent manner. Angiogenic activities of endothelial cells were greatly enhanced after co-cultured with NGF pre-treated chondrocytes, while knock-down of TrkA significantly abolished the above effects. We further found that NGF-induced expression of FGF2 promoted angiogenic activities of endothelial cells through PI3K/Akt and ERK/MAPK signaling pathways.

CONCLUSIONS

NGF promotes expression of FGF2 in vitro via PI3K/Akt and ERK/MAPK signaling pathways in human chondrocytes and it increases angiogenesis, which is mediated by TrkA. NGF could be responsible for vascular up-growth from subchondral bone in OA.

Role of bisphosphonates in the management of acute Charcot foot

Diabetes mellitus is the most common cause of Charcot neuropathy affecting foot and ankle. Acute Charcot foot (CF) presents with a red and swollen foot in contrast to the painless deformed one of chronic CF. Enhanced osteoclastogenesis plays a central role in the pathogenesis of acute CF. Many studies have shown elevated levels of bone turnover markers in patients with acute CF confirming it. These findings have led clinicians to use anti-resorptive agents [bisphosphonates (BP), calcitonin, and denosumab] along with immobilization and offloading in acute CF patients. The maximum evidence among all anti-resorptive agents is available for BPs, although its quality is low. Pamidronate has been shown to reduce the markers of activity of CF like raised skin temperature, pain, edema, and bone turnover markers in the majority of studies. Intravenous BPs are known to cause acute phase reactions leading to flu-like illness following their first infusion, which can be ameliorated by oral acetaminophen. Alendronate is the only oral BP used in these patients. It needs to be taken on an empty stomach with a full glass of water to avoid esophagitis. The side-effects and contraindications to BPs should be kept in mind while treating acute CF patients with them.

A Factor Increasing Venous Contamination on Bolus Chase Three-dimensional Magnetic Resonance Imaging: Charcot Neuroarthropathy

Background

The study aimed to evaluate the ratio of venous contamination in diabetic cases without foot lesion, with foot lesion and with Charcot neuroarthropathy (CN).

Materials and Methods

Bolus-chase three-dimensional magnetic resonance (MR) of 396 extremities of patients with diabetes mellitus was analyzed, retrospectively. Extremities were divided into three groups as follows: diabetic patients without foot ulcer or Charcot arthropathy (Group A), patients with diabetic foot ulcers (Group B) and patients with CN accompanying diabetic foot ulcers (Group C). Furthermore, amount of venous contamination classified as no venous contamination, mild venous contamination, and severe venous contamination. The relationship between venous contamination and extremity groups was investigated.

Results

Severe venous contamination was seen in Group A, Group B, and Group C, 5.6%, 15.2%, and 34.1%, respectively. Statistically significant difference was seen between groups with regard to venous contamination.

Conclusion

Venous contamination following bolus chase MR was higher in patients with CN.

Treatment of Charcot Neuroarthropathy and osteomyelitis of the same foot: a retrospective cohort study

BACKGROUND

We evaluated treatment of osteomyelitis in the foot in the presence of Charcot neuroarthropathy, a devastating condition with progressive degeneration and joint destruction. We hypothesized that there was a difference in (1) amputation rate, (2) amputation level, (3) duration of antibiotic therapy, and (4) duration of immobilization for treatment of osteomyelitis within versus outside the Charcot zone.

METHODS

Forty patients (43 ft) diagnosed with Charcot neuroarthropathy and osteomyelitis of the same foot were retrospectively analyzed. Some patients were successfully treated for osteomyelitis at different sites on the same foot at different times, thus 60 cases of osteomyelitis were identified in 40 treated patients. Cases were divided according to osteomyelitis localization: Group 1 had osteomyelitis outside the active Charcot region; Group 2 had osteomyelitis within the active Charcot region.

RESULTS

Male patients (n = 29; mean age 58.2, range 40.1 to 77.5 years) were younger than female patients (n = 11; mean age 70.4, range 51.4 to 87.5, p = 0.02 years). Amputation rate was 52% overall (26/40 patients; 26/43 ft): 63% of 30 Group 1 cases and 40% of 30 Group 2 cases (p = 0.09). Amputation level (p = 0.009), duration of antibiotic treatment (p = 0.045) and duration of immobilization (p = 0.01) differed significantly between the groups.

CONCLUSIONS

Osteomyelitis within the Charcot region is associated with a higher level of amputation and longer durations of antibiotic therapy and immobilization. Osteomyelitis outside and within the Charcot affected region should be considered separately. If osteomyelitis occurs outside the active Charcot region, primary amputation may be preferred to internal resection.

LEVEL OF EVIDENCE

Retrospective cohort chart review study.

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.

Charcot Arthropathy Versus Osteomyelitis: Evaluation and Management

Charcot arthropathy of the foot and ankle is a severe complication of peripheral neuropathy and is most commonly seen in the developed world in association with diabetes mellitus. Correct diagnosis and differentiation from osteomyelitis of the foot and ankle are critical to guide treatment. It can exist concomitantly with osteomyelitis, typically in the setting of an advanced midfoot ulcer. Simple plain radiographs and contrasted MRI studies often yield inconclusive or confusing data. Correct use of imaging studies and a clinical algorithm can be effective tools to help make accurate and early diagnoses and guide clinical interventions for these conditions.

Surgical Equinus Correction for the Diabetic Charcot Foot: What the Evidence Reveals

Triceps surae contracture, or equinus, is a known deforming force in the foot and ankle. Biomechanical studies have shown that ankle equinus significantly alters gait and plantar pressures, and in the diabetic neuropathic patient population, this can propagate plantar ulceration and/or Charcot neuroarthropathy (CN). Surgical correction of equinus is globally and frequently used to aid in plantar wound healing in the neuropathic diabetic patient, with and without CN. Treatment guidelines for equinus correction in this medically complex population are undefined and lack evidence from high-quality published peer-reviewed studies.

The Effect of Charcot Neuroarthropathy on Limb Preservation in Diabetic Patients with Foot Wound and Critical Limb Ischemia after Balloon Angioplasty

OBJECTIVE

The aim of this article is to investigate one-year limb preservation rates after below-the-knee angioplasty in patients with diabetic foot wound who only have critical limb ischemia (CLI) and those who have Charchot neuroarthropathy (CN) accompanied by CLI.

METHODS

This single-center, retrospective study consists of 63 patients with diabetic foot wound who had undergone lower extremity balloon angioplasty of at least 1 below-the-knee (BTK) vessel. Only those patients with postprocedural technical success of 100% were selected from the database. All patients were classified into two groups as patients with CLI and CN and patients with CLI only without CN. The Kaplan-Meier method was used to compare the limb preservation rates for the two groups.

RESULTS

There was no statistically significant difference between patient age, gender, diabetic disease duration, and comorbid disease such as chronic renal insufficiency, hypertension, and coronary artery disease of the two groups (p > 0.05). Limb preservation in the 12 months was 59.1% in the CN group and 92.7% in the group without CN. Also, limb preservation rates between the two groups displayed statistically significant differences (p < 0.005).

CONCLUSION

This study showed that CLI can accompany CN in patients with diabetes. Limb preservation rates with endovascular treatment in diabetic patients with CLI only are better than in diabetic patients with CLI and CN.

When Is Osteonecrosis Not Osteonecrosis?: Adjudication of Reported Serious Adverse Joint Events in the Tanezumab Clinical Development Program

OBJECTIVE

Tanezumab, a monoclonal antibody against nerve growth factor, has demonstrated efficacy in clinical trials of chronic pain in osteoarthritis (OA) and chronic low back pain. Unexpected adverse events (AEs) described as osteonecrosis (ON) occurred during tanezumab development, leading the US Food and Drug Administration to impose a partial clinical hold for all indications except cancer pain. A blinded Adjudication Committee (AC) including orthopedic surgeons, rheumatologists, and an orthopedic pathologist reviewed and adjudicated joint-related AEs in the tanezumab clinical program.

METHODS

The AC adjudicated all reported cases of ON as well as cases of total joint replacements (TJRs) not reported as ON for which radiographs obtained within 9 months of the surgery were available. The AC prespecified categories for joint safety events including primary ON, worsening OA (rapid progression of OA [RPOA], normal progression of OA, insufficient information to distinguish between rapid and normal progression of OA), other, or insufficient information to distinguish between primary ON and worsening OA or another diagnosis.

RESULTS

The AC reviewed events in 249 of 386 patients with an investigator-reported AE of ON and/or a TJR. Two events were adjudicated as primary ON, 200 events were adjudicated as worsening OA (68 of which were classified as RPOA), 29 events had another diagnosis, 11 had insufficient information to distinguish primary ON from worsening OA, and 7 did not have committee member consensus.

CONCLUSION

Despite initial reports, tanezumab treatment was not associated with an increase in ON but was associated with an increase in RPOA. Higher doses of tanezumab, tanezumab administered with nonsteroidal antiinflammatory drugs, and preexisting subchondral insufficiency fractures were risk factors for RPOA in this cohort.

Pathological role of fibroblast-like synoviocytes in charcot neuroarthropathy

This study was designed to characterize the synovium in the joints of Charcot neuroarthropathy (CNA) and investigate the potential role of fibroblast-like synoviocytes (FLS) in the pathology of CNA. Synovial samples were collected from CNA patients (n = 7) and non-CNA patients (n = 7), for control, during orthopaedic procedures and used for histology and isolation of FLS. Histological characterization of synovium included innervation and FLS localization. The isolated FLS from the CNA and non-CNA synovium were cultured, with or without tumor necrosis factor-α (TNF-α), for evaluation of invasiveness, gene expression, and cartilage degradation. Vasoactive intestinal peptide (VIP), a neuropeptide, was supplemented into the co-cultures of FLS and cartilage explants. Compared with the non-CNA synovium, CNA synovium was highly inflammatory, with reduced innervation and intense expression of cadherin-11. The FLS isolated from CNA synovium, particularly when activated with TNF-α, were more invasive, increased the expression of ADAMTS4, IL-6, and RANKL, and depleted proteoglycans from cartilage explants when they were co-cultured. Addition of VIP into the culture medium neutralized the catabolic effect of the CNA FLS on cartilage explants. In conclusion, FLS plays an important role in the pathology of CNA. Therapies targeting synovium and FLS may prevent or treat the joint destruction in CNA.

Surgical Reconstruction of Charcot Foot Neuroarthropathy, a Case Based Review

Our case-based review focuses on limb salvage through operative management of Charcot neuroarthropathy of the diabetic foot. We describe a case, when a below-knee amputation was considered in a patient with chronic Charcot foot with a rocker-bottom deformity and chronic plantar ulceration. Conservative treatment failed. Targeted antibiotic therapy and operative management (Tendo-Achilles lengthening, resectional arthrodesis of Lisfranc and midtarsal joints, fixation with large-diameter axial screws, and plaster cast) were performed. On the basis of this case, we discuss options and drawbacks of surgical management. Our approach led to healing of the ulcer and correction of the deformity. Two years after surgery, we observed a significant improvement in patient’s quality of life. Advanced diagnostic and imaging techniques, a better understanding of the biomechanics and biology of Charcot neuroarthropathy, and suitable osteosynthetic material enables diabetic limb salvage.

Serious joint-related adverse events in randomized controlled trials of anti-nerve growth factor monoclonal antibodies

BACKGROUND

Reports of serious joint adverse events (AEs) due to osteonecrosis were noted during randomized placebo-controlled clinical trials of monoclonal antibodies to nerve growth factor (NGF), including tanezumab and fulranumab.

METHODS

All available medical records from subjects with reported cases of osteonecrosis, as well as records of subjects who underwent joint replacement during these studies, were reviewed by an independent adjudication committee that was established by each company; the committees were different for each company and included distinct individual experts. Cases were categorized as having definite osteonecrosis, normal or rapid progression of osteoarthritis (OA), another diagnosis or unable to determine the underlying diagnosis.

RESULTS

The vast majority of investigator reported cases of osteonecrosis were adjudicated as either normal or rapid progression of OA. Indeed, the syndrome of rapid progression of OA associated with chondrolysis and bone destruction appears to be a safety signal that is associated with not only increasing doses of anti-NGF antibodies but also concomitant therapy with nonsteroidal anti-inflammatory drugs.

CONCLUSIONS

These results have implications for future clinical trials of anti-NGF agents in OA and other painful conditions.

Diabetic charcot neuroarthropathy of the foot and ankle with osteomyelitis

One of the most devastating foot and/or ankle complications in the diabetic population with peripheral neuropathy is the presence of Charcot neuroarthropathy (CN). In recent years, diabetic limb salvage has been attempted more frequently as opposed to major lower extremity amputation for CN of the foot and ankle with ulceration and/or deep infection. Treatment strategies for osteomyelitis in the diabetic population have evolved. This article reviews some of the most common surgical strategies recommended for the diabetic patient with CN of the foot and/or ankle and concomitant osteomyelitis.

Charcot arthropathy of the lumbosacral spine mimicking a vertebral tumor after spinal cord injury

Charcot spinal arthropathy is a rare, progressive type of vertebral joint degeneration that occurs in the setting of any preexisting condition characterized by decreased afferent innervation to the extent that normal protective joint sensation in the vertebral column is impaired. The authors report on a case of Charcot arthropathy of the lower lumbar spine mimicking a spinal tumor following cervical cord injury.

Charcot neuroarthropathy of the foot and ankle: diagnosis and management strategies

This article reviews current literature discussing the etiology, pathophysiology, diagnosis and imaging, and conservative and surgical treatment of Charcot osteoarthropathy. The treatment of Charcot osteoarthropathy with concurrent osteomyelitis is also discussed.

Charcot foot in diabetes and an update on imaging

Charcot neuroarthropathy (CN) is a serious complication of diabetes mellitus that can cause major morbidity including limb amputation. Since it was first described in 1883, and attributed to diabetes mellitus in 1936, the diagnosis of CN has been very challenging even for the experienced practitioners. Imaging plays a central role in the early and accurate diagnosis of CN, and in distinction of CN from osteomyelitis. Conventional radiography, computed tomography, nuclear medicine scintigraphy, magnetic resonance imaging, and positron emission tomography are the imaging techniques currently in use for the evaluation of CN but modalities other than magnetic resonance imaging appeared to be complementary. This study focuses on imaging findings of acute and chronic neuropathic osteoarthropathy in diabetes and discrimination of infected vs. non-infected neuropathic osteoarthropathy.

Charcot foot and ankle with osteomyelitis

This paper presents a review of the current literature discussing topics of Charcot osteoarthropathy, osteomyelitis, diagnosing osteomyelitis, antibiotic management of osteomyelitis, and treatment strategies for management of Charcot osteoarthropathy with concurrent osteomyelitis.

An overview of the Charcot foot pathophysiology

Charcot arthropathy of the foot is a rare but devastating complication of diabetes that remains to be a challenging issue for the foot and ankle surgeons. Charcot foot fails to be an obvious diagnostic option that comes to mind, even in a pathognomonic clinical appearance. The rarity of the disorder, more common pathologies that mimic the condition, and the self-limiting prognosis deviate the clinician from the right diagnosis. The clinical challenges in the diagnosis of Charcot foot require in-depth investigations of its enigmatic nature to establish useful guidelines. Yet, this goal seems to be beyond reach, without a holistic view of the immense literature concerning the pathophysiology of the disorder. The primary objective of this article is to put together and review the recent advancements about the etiology and intrinsic mechanisms of diabetic Charcot foot.

Charcot arthropathy of the shoulder associated with typical and atypical findings

We present a patient with a relatively rare condition: Charcot joint of the shoulder, with a rare complication, the first known example of combined neurovascular compression in this location. A 49-year-old man presented with neuropathic arthropathy of the shoulder caused by syringomyelia from a Chiari I malformation, leading to compression of both the brachial plexus and the axillary vein by mass effect from the synovitis. The brachial plexopathy resolved with surgical decompression and synovectomy, and the syringomyelia stabilized after Chiari decompression. A large acromioclavicular joint synovial cyst developed as a late complication, which was treated nonoperatively. Understanding neuropathic arthropathy can explain the spectrum of interrelated typical and atypical features in this case over long-term follow-up.