Minocycline-induced black bone disease encountered during total knee arthroplasty

Black discoloration of the knee articular cartilage in a patient with pigmented villonodular synovitis: A case report

In this case report, total knee arthroplasty was performed in a patient with pigmented villonodular synovitis. During surgery, severe black discoloration of the articular cartilage and menisci was observed in the patient. According to literatures, this is the first case report of severe articular cartilage pigmentation in a patient with pigmented villonodular synovitis.

Tetracyclines and bone: Unclear actions with potentially lasting effects

Tetracyclines are a broad-spectrum class of antibiotics that have unclear actions with potentially lasting effects on bone metabolism. Initially isolated from Streptomyces, tetracycline proved to be an effective treatment for Gram +/- infections. The emergence of resistant bacterial strains commanded the development of later generation agents, including minocycline, doxycycline, tigecycline, sarecycline, omadacycline, and eravacycline. In 1957, it was realized that tetracyclines act as bone fluorochrome labels due to their high affinity for the bone mineral matrix. Over the course of the next decade, researchers discerned that these compounds are retained in the bone matrix at high levels after the termination of antibiotic therapy. Studies during this period provided evidence that tetracyclines could disrupt prenatal and early postnatal skeletal development. Currently, tetracyclines are most commonly prescribed as a long-term systemic therapy for the treatment of acne in healthy adolescents and young adults. Surprisingly, the impact of tetracyclines on physiologic bone modeling/remodeling is largely unknown. This article provides an overview of the pharmacology of tetracycline drugs, summarizes current knowledge about the impact of these agents on skeletal development and homeostasis, and reviews prior work targeting tetracyclines' effects on bone cell physiology. The need for future research to elucidate unclear effects of tetracyclines on the skeleton is addressed, including drug retention/release mechanisms from the bone matrix, signaling mechanisms at bone cells, the impact of newer third generation tetracycline antibiotics, and the role of the gut-bone axis.

Minocycline black bone disease in arthroplasty: a systematic review

BACKGROUND

Minocycline black bone disease is a rare finding that can cause concern when unexpectedly encountered during routine arthroplasty. Prolonged minocycline use can cause selective staining of subchondral bone, whilst peri-articular soft tissue and cartilage appear uninvolved.

METHODS

A systematic review according to PRISMA guidelines was performed to identify all reported cases in the literature.

RESULTS

Including the patient we present, eleven cases of minocycline black bone disease encountered during arthroplasty have been reported in the literature. All cases have had an excellent outcome, with no complications reported to date.

CONCLUSIONS

Minocycline black bone disease can be a concerning intra-operative finding when unexpectedly encountered during routine arthroplasty, but should not affect the operative plan. Surgeons should exclude alternative causes of bone discolouration when the history is unclear.

Minocycline-induced black bone disease with synovial pigmentation in a patient undergoing revision anterior cruciate ligament surgery: A case report

INTRODUCTION

Long-term use of minocycline at high doses is associated with hyperpigmentation with multiple sites of involvement. While the cutaneous organs and the oral cavity are most commonly affected, bone discoloration is a rare entity.

CASE PRESENTATION

A 19-year-old male patient with a history of acne vulgaris and intermittent treatment with high dose minocycline for three years presented with recurrent anterior cruciate ligament (ACL) tear. During arthroscopic surgery, however, hyperpigmentation of the femur and synovium was observed. Abnormal tissue was biopsied and confirmed through histopathological examination to contain melanin-related minocycline pigmentation. Revision surgery was re-scheduled with no intraoperative complications and excellent long-term clinical outcomes.

CLINICAL DISCUSSION

There are several possible causes of hyperpigmentation, including hemosiderin deposition, infection, aseptic necrosis, demineralization, and metastatic disease. Black bone disease, caused by minocycline-induced hyperpigmentation, is rare. While the appearance is grossly abnormal in black bone disease, there has been no evidence suggesting that tissue integrity is compromised.

CONCLUSION

This case confirms that hyperpigmentation does not affect bone integrity and that surgical procedures can be performed safely. Knowing the adverse effects of minocycline administration could reduce inappropriate postponement of surgical procedures, thereby saving time and resources.

Long-term follow-up of bilateral hip and knee arthroplasty secondary to ochronotic arthropathy

Alkaptonuria is a rare metabolic disorder caused by the deficiency of homogentisic acid oxidase enzyme, which is responsible for eliminating homogentisic acid from the body through the renal system. Excessive accumulation of homogentisic acid leads to ochronosis and ochronotic arthritis. Owing to the rarity of the disease, long-term functional outcomes of joint replacements of the hips and knees in ochronosis arthropathy are unconfirmed, and only a limited number of case reports are available on this. We present a case of a 45-year-old man with ochronosis and advanced osteoarthritis of both the hips and knees. He underwent bilateral hip and knee replacements as staged procedures. At a follow-up of more than 12 years, the man had full mobility with no loosening of implants.

Total Knee Arthroplasty in Ochronosis Arthropathy: A Case Report and Systematic Review

INTRODUCTION

Ochronosis arthropathy (OcA) is a rare condition which may be treated with total knee arthroplasty (TKA) at the end stage. The condition is often discovered only intraoperatively and the ideal choice of TKA is unknown.

CASE PRESENTATION

A 54-year-old male with worsening chronic bilateral mechanical knee pain had failed conservative therapy. Posterior stabilised (PS), cemented TKA and patella resurfacing was performed. Intraoperatively, collagenous structures such as the menisci and cartilage were noted to be black. Histological examination showed deposition of large amorphous brown material suggestive of ochronosis. He recovered well and underwent TKA of the contralateral knee the following year. At 2 years postindex TKA, his outcome scores improved and he was satisfied.

DISCUSSION AND CONCLUSION

With increasing TKA performed worldwide, a surgeon may eventually be surprised by the above findings once in their lifetime. However, OcA may be considered a likely diagnosis and it is safe to proceed with TKA. There is no particular TKA design that proved to be superior in our systematic review of 19 publications regarding TKA as all reported good outcomes. However, as the pathogenesis of OcA appears to be inflammatory in nature, we suggest using cemented PS TKA with resurfacing of the patella.

Inhibition of the cluster of differentiation 14 innate immunity pathway with IAXO-101 improves chronic microelectrode performance

OBJECTIVE

Neuroinflammatory mechanisms are hypothesized to contribute to intracortical microelectrode failures. The cluster of differentiation 14 (CD14) molecule is an innate immunity receptor involved in the recognition of pathogens and tissue damage to promote inflammation. The goal of the study was to investigate the effect of CD14 inhibition on intracortical microelectrode recording performance and tissue integration.

APPROACH

Mice implanted with intracortical microelectrodes in the motor cortex underwent electrophysiological characterization for 16 weeks, followed by endpoint histology. Three conditions were examined: (1) wildtype control mice, (2) knockout mice lacking CD14, and (3) wildtype control mice administered a small molecule inhibitor to CD14 called IAXO-101.

MAIN RESULTS

The CD14 knockout mice exhibited acute but not chronic improvements in intracortical microelectrode performance without significant differences in endpoint histology. Mice receiving IAXO-101 exhibited significant improvements in recording performance over the entire 16 week duration without significant differences in endpoint histology.

SIGNIFICANCE

Full removal of CD14 is beneficial at acute time ranges, but limited CD14 signaling is beneficial at chronic time ranges. Innate immunity receptor inhibition strategies have the potential to improve long-term intracortical microelectrode performance.

Understanding the Role of Innate Immunity in the Response to Intracortical Microelectrodes

Intracortical microelectrodes exhibit enormous potential for researching the nervous system, steering assistive devices and functional electrode stimulation systems for severely paralyzed individuals, and augmenting the brain with computing power. Unfortunately, intracortical microelectrodes often fail to consistently record signals over clinically useful periods. Biological mechanisms, such as the foreign body response to intracortical microelectrodes and self-perpetuating neuroinflammatory cascades, contribute to the inconsistencies and decline in recording performance. Unfortunately, few studies have directly correlated microelectrode performance with the neuroinflammatory response to the implanted devices. However, of those select studies that have, the role of the innate immune system remains among the most likely links capable of corroborating the results of different studies, across laboratories. Therefore, the overall goal of this review is to highlight the role of innate immunity signaling in the foreign body response to intracortical microelectrodes and hypothesize as to appropriate strategies that may become the most relevant in enabling brain-dwelling electrodes of any geometry, or location, for a range of clinical applications.

Black Bone Disease of the Foot: A Two-Year Follow-Up Case Study

"Black bone disease" is a term commonly used to describe a condition characterized by a blue/green/brown discoloration to the bone that often resembles infracted or necrotic bone. The chronic use of minocycline or tetracycline has been reported in previous data as a cause of this discoloration to the skin, bone, and teeth. However, the occurrence in bone is rare, with few studies reported regarding the discoloration. We previously presented a case of this condition encountered during cheilectomy of the first metatarsophalangeal joint in a patient who had had long-term usage of minocycline for adult acne. Two years after the initial case, the patient returned for correction of a hammertoe deformity on the second left proximal phalanx of the same foot. We present the findings and photographs from the second surgery. In addition, we have provided the relevant case data and figures from the first case for ease of comparison.

Black pigmentation of both forearm bones after chronic minocycline antibiotic therapy for septic nonunion. A case report and literature review

We report the case of a 28-year-old man with a septic forearm non-union treated with minocycline for 3 months. At the time of reconstructive surgery, the radius and ulna were entirely black. Surgical debridement until bleeding of both bone extremities resulted in a 5-cm defect that was filled with a cement spacer. Histology confirmed poorly vascularized bone with focal areas of acute inflammatory infiltrate at the non-union sites (highly suggestive of infection) and normal structure of the remaining diaphyseal bones, although black in color. Reconstruction with free vascularized fibula transfer was successful leading to complete bone healing. An incidental finding of minocycline-induced black bone discoloration should not change the surgeon's decision because there is no evidence of adverse effects on bone healing in the literature. Surgery can be performed safely at sites of minocycline-induced black bone pigmentation.

Anti-inflammatory Approaches to Mitigate the Neuroinflammatory Response to Brain-Dwelling Intracortical Microelectrodes

Intracortical microelectrodes are used both in basic research to increase our understanding of the nervous system and for rehabilitation purposes through brain-computer interfaces. Yet, challenges exist preventing the widespread clinical use of this technology. A prime challenge is with the neuroinflammatory response to intracortical microelectrodes. This mini-review details immunomodulatory strategies employed to decrease the inflammatory response to these devices. Over time, broad-spectrum anti-inflammatory approaches, such as dexamethasone and minocycline, evolved into more targeted treatments since the underlying biology of the neuroinflammation was elucidated. This review also presents studies which examine novel prospective targets for future immunomodulatory targeting.

Case Study: An intraoperative finding of black bone disease in a podiatric surgery patient

Black bone disease has been recognised as a potential consequence of long-term treatment with tetracycline antibiotics. Largely documented affecting structures in the head and skull, there are few reported cases of black bone disease in the foot and ankle. The case of a 55 years old patient, who as a teenager, had undergone treatment with minocycline hydrochloride for chronic acne, and was found to have bone discolouration consistent with minocycline induced black bone disease (MIBBD) during the course of hallux valgus corrective surgery some 40 years later, is presented. In spite of the intraoperative findings, the patient's post-operative recovery and bone healing was uneventful. The literature on minocycline induced black bone disease is reviewed.

Black Colouration of the Knee Articular Cartilage after Spontaneously Recurrent Haemarthrosis

Mild discolouration of the articular cartilage is known to gradually occur during aging. However, pathological tissue pigmentation is occasionally induced under several specific conditions. In the present case, we performed total knee replacement in a patient with recurrent haemarthrosis. However, during the operation, we observed severe black colouration of the knee articular cartilage, due to the deposition of hemosiderin and lipofuscin. To our knowledge, this is the first report of severe cartilage pigmentation, due to hemosiderin and lipofuscin deposition in articular cartilage.

Black bone disease in a healing fracture

Black bone disease refers to the hyperpigmentation of bone secondary to prolonged usage of minocycline. We present a report of a 34-year-old man who underwent femoral shaft fracture fixation complicated by deep infection requiring debridement. The implants were removed 10 months later after long-term treatment with minocycline and fracture union. A refracture of the femoral shaft occurred 2 days after implant removal and repeat fixation was required. Intraoperatively, abundant heavily pigmented and dark brown bone callus was noted over the old fracture site. There was no evidence of other bony pathology and the appearance was consistent with minocycline-associated pigmentation. As far as we are aware, this is the first case of black bone disease affecting callus within the interval period of bone healing. We also discuss the relevant literature on black bone disease to bring light on this rare entity that is an unwelcomed surprise to operating orthopaedic surgeons.

Rusty green stained temporal bone associated with exposure to tetracycline: an unusual presentation of black bone disease

OBJECTIVE

To review the phenomenon and implications of temporal bone and craniofacial bone staining in the context of prolonged exposure to tetracycline antibiotic.

METHODS

Case report and literature review.

RESULTS

A 52-year-old male with a 5-year history of tetracycline use presented to undergo tympanomastoidectomy and was found to have an unusual rusty green pigmentation of the entire aspect of the exposed temporal bone. A literature review revealed more than 20 cases of tetracycline-induced pigmentation of intraoral maxillary and mandibular bone, and 2 prior cases involving the cranial bones.

CONCLUSION

Tissue and organ pigmentation is an unexpected and unfavourable consequence of the use of tetracyclines, particularly minocycline. Tetracycline is contraindicated in children because of the risk for dysosteogenesis and enamel hypoplasia. In adults, although the unusual staining may present as an unexpected dilemma upon surgical exposure, current research shows no significant clinical consequences for this type of pigmentation.

Antibiotic precautions in athletes

CONTEXT

Antibiotics are the mainstay of treatment for bacterial infections in patients of all ages. Athletes who maximally train are at risk for illness and various infections. Routinely used antibiotics have been linked to tendon injuries, cardiac arrhythmias, diarrhea, photosensitivity, cartilage issues, and decreased performance.

EVIDENCE ACQUISITION

Relevant articles published from 1989 to 2012 obtained through searching MEDLINE and OVID. Also, the Food and Drug Administration website was utilized.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 3.

RESULTS

The team physician should consider alternative medications in place of the "drug of choice" when adverse drug effects are a concern for an athlete's health or performance. If alternative medications cannot be selected, secondary preventative measures, including sunscreen or probiotics, may be needed.

CONCLUSION

Physicians choose medications based on a variety of factors to help ensure infection resolution while limiting potential side effects. Extra precautions are indicated when treating athletes with certain antibiotics.

On the ocular findings in ochronosis: a systematic review of literature

BACKGROUND

Ochronosis/Alkaptonuria is a tyrosine metabolism disorder where accumulation of homogentisic acid, in eye, skin, cartilage and several other connective tissues leads to a black pigmentation of the affected tissues. It is autosomal-recessive inherited in men with a frequency of 1-9/1,000,000. While it is clear that pigment deposits lead to joint destruction, renal stone formation and cardiac valvulopathy respectively, the significance of ocular findings is still unclear. We therefore aim to evaluate the frequency and clinical significance of ocular findings in ochronosis and discuss possible therapeutic options.

METHODS

Systematic review of literature via Medline and Web of Science. Only case reports in English, German, French, Spanish or Italian documenting detailed ophthalmologic examination were included.

RESULTS

Our search revealed 36 case reports including 40 patients. Average age at the onset of ocular signs was 40.6 years. The most frequent sign was symmetric brown sclera pigmentation present in 82.5 percent of the patients. "Oil-drops", brown pigment spots in the limbus are generally considered pathognomonic but were a little less frequent (75 percent). Vermiform pigment deposits at the level of the conjunctiva or increased conjunctival vessel diameter is also frequent. We found an increased incidence of central vein occlusion and elevated intraocular pressure going along with chamber angle hyperpigmentation. Another condition observed twice is rapid progressive astigmatism attributable to corneoscleral pigment accumulation.

CONCLUSION

Our observations suggest that ocular findings are of double relevance. First, characteristic ocular findings can anticipate the time of diagnosis and second, ocular findings may complicate to various conditions putting sight at risk. Opthalmologists and general physicians should be aware of both. Therapeutic options include protein restriction, administration of high dose vitamin C or nitisonone. Evidence for all of them is limited.

The Effect of Residual Endotoxin Contamination on the Neuroinflammatory Response to Sterilized Intracortical Microelectrodes

A major limitation to the use of microelectrode technologies in both research and clinical applications is our inability to consistently record high quality neural signals. There is increasing evidence that recording instability is linked, in part, to neuroinflammation. A number of factors including extravasated blood products and macrophage released soluble factors are believed to mediate neuroinflammation and the resulting recording instability. However, the roles of other inflammatory stimuli, such as residual endotoxin contamination, are poorly understood. Therefore, to determine the effect of endotoxin contamination we examined the brain tissue response of C57/BL6 mice to non-functional microelectrodes with a range of endotoxin levels. Endotoxin contamination on the sterilized microelectrodes was measured using a limulus amebocyte lysate test following FDA guidelines. Microelectrodes sterilized by autoclave, dry heat, or ethylene oxide gas, resulted in variable levels of residual endotoxins of 0.55 EU/mL, 0.22 EU/mL, and 0.11 EU/mL, respectively. Histological evaluation at two weeks showed a direct correlation between microglia/macrophage activation and endotoxin levels. Interestingly, astrogliosis, neuronal loss, and blood brain barrier dysfunction demonstrated a threshold-dependent response to bacterial endotoxins. However, at sixteen weeks, no histological differences were detected, regardless of initial endotoxin levels. Therefore, our results demonstrate that endotoxin contamination, within the range examined, contributes to initial but not chronic microelectrode associated neuroinflammation. Our results suggest that minimizing residual endotoxins may impact early recording quality. To this end, endotoxins should be considered as a potent stimulant to the neuroinflammatory response to implanted intracortical microelectrodes.