John Antoniou

• MD PhD FRCSC
• McGill University

Objectives Total hip arthroplasty (THA) and resurfacing hip arthroplasty (RHA) offer promising therapeutic solutions to physically active patients with hip osteoarthritis (OA). The impact of physical activity on long-term implant integrity in this population remains unknown. This systematic review compares the impact of physical activity and sports...

Background: Robotic technology has been used in total hip arthroplasty (THA) for several years. Despite the advances in this field, perspectives surrounding robotic THA are not fully understood. This study aimed to characterize the landscape of robotic THA on social media. Methods: The Twitter application programming interface was queried from i...

Emerging evidence indicates periostin (POSTN) is upregulated in patients with OA, and studies have shown that it can induce the activation of inflammatory cytokines and catabolic enzymes, making it a potential therapeutic target. Link N (LN) is a peptide fragment derived from the link protein and has been demonstrated as an anabolic-like factor and...

Intervertebral disc degeneration and pain are associated with the nucleotide-binding domain, leucine-rich repeat, and pyrin domain-containing 3 (NLRP3) inflammasome activation and the processing of interleukin-1 beta (IL-1β). Activation of thehm inflammasome is triggered by Toll-like receptor stimulation and requires the cofactor receptor cluster o...

Short stems have been developed to conserve bone stock, especially in younger populations undergoing a total hip arthroplasty (THA), and showed similar functional outcomes compared to conventional stems. Recent literature suggested that stem length might be an independent risk factor for acute periprosthetic femoral fracture in direct anterior THA...

Immunoglobulin A (IgA) nephropathy in the presence of a metal-on-metal (MoM) hip arthroplasty is a rare condition that requires close monitoring. A 61-year-old male with bilateral hip osteoarthritis underwent resurfacing hip arthroplasty with MoM articulating surfaces. Prior to his four-year postoperative visit, the patient was diagnosed with IgA n...

Objective Recommendations discouraging high levels of physical activity and sports following unicompartmental (UKA) and total knee arthroplasty (TKA) have been questioned in recent years. This scoping review aimed to summarize the literature examining the impact of physical activity level and sports participation on implant integrity and failure in...

Objectives Total hip arthroplasty is a successful procedure for treating advanced osteoarthritis (OA). Metal bearing surfaces remain one of the most widely implanted prosthesis, however approximately 10% of patients develop adverse local tissue reactions (ALTRs), namely lymphocytic predominant soft tissue reaction with or without necrosis and osteo...

Background: The number of total knee arthroplasty (TKA) procedures performed annually is increasing for reasons not fully explained by population growth and increasing rates of obesity. The purpose of this study was to determine the role of patient functional status as an indication for surgery and to determine if patients are undergoing surgery w...

To compare short-term complications and readmission rates, in patients treated with simultaneous versus staged bilateral total hip arthroplasty (THA) within a year from the index procedure. We reviewed the charts of patients that underwent simultaneous and staged—within a year—bilateral THA, between 2016 and 2020. Preoperative baseline characterist...

This is a reply to the Letter to the Editor by Ozden & Dikmen regarding our article titled "Outcomes of Ceramic-On-Ceramic Bearing Total Hip Arthroplasty: A Minimum 10-Year Follow-Up Study"

Background: Although the fourth generation of ceramics has demonstrated excellent clinical results 5 to 6 years postoperatively, concerns over ceramic fracture and squeaking persist and longer-term follow-up (minimum 10 years) studies are warranted. Our study aimed to evaluate the minimum 10-year clinical outcomes and bearing-specific complication...

Distal tibiofibular syndesmosis injuries can be stabilized with syndesmotic screws or suture-buttons. The objective was to compare ankle motion during gait and a step-down task between patients that had syndesmotic screw or suture-button fixation and healthy adults. This case series included two participants who received a syndesmotic screw and two...

Sarcoma arising at the site of a total hip arthroplasty (THA) is uncommon. We present a case report of a patient diagnosed with an osteosarcoma around a ceramic-on-ceramic THA and a narrative literature review of sarcomas around THA. A search of PubMed MEDLINE was performed from inception. Our case report was included in the analysis. A total of 13...

The purpose of this symposium was to provide guidance to innovators as they progress from the idea stage to the product development stage,to the issuing of a patent, and to bringing a product or innovation to market. Finding strategic partnerships is a critical component in taking a good idea and turning it into a successful business. Protecting in...

Background Revision surgery is usually required for complications associated with total hip arthroplasty (THA). Significant morbidity can be associated with revision THA and thus some may only revise the liner of the original metal back component if it is found to be well fixed. We compare the long-term survivorship of cemented and uncemented head-...

Background After the COVID-19 pandemic declaration in March 2020, all the elective total joint replacement surgeries in Canada were abruptly canceled for an indefinite period of time. The principal objective of this study was to determine the prevalence of psychological morbidity experienced by arthroplasty surgeons during the peak of the first wav...

Background The aim of this study is to assess the independent effect of age on the risk of postsurgical complications and death in patients undergoing total hip arthroplasty (THA). Methods The National Surgical Quality Improvement Program was used to identify all patients aged 65 years and older who underwent primary THA from 2011 to 2017. Study o...

Objective: To examine if relationships between knee osteoarthritis (OA) progression with knee moments and muscle activation during gait vary between patients with non-traumatic and post-traumatic knee OA. Design: This longitudinal study included participants with non-traumatic (n=17) and post-traumatic (n=18) knee OA; the latter group had a prev...

Background The number of total hip arthroplasties (THAs) performed per year is increasing for reasons not fully explained by a growing and aging population. The purpose of this study was to determine the role of patient functional status as an indication for surgery and determine if patients are undergoing surgery at a better functional status than...

This chapter presents a case scenario of a 48‐year‐old healthy male who presents with right groin pain that has progressively limited his work and leisure activities over the last two years. Clinical examination of the affected hip reveals restricted motion and antalgia while radiographs demonstrate advanced degenerative joint disease. Hip resurfac...

This chapter presents a case scenario of a 41‐year‐old male who presented with a two‐year history of progressive left groin pain on weight bearing. He had a total hip arthroplasty (THA) performed 15 years ago for osteoarthritis of his left hip secondary to a displaced fracture of the acetabular dome. The goal of revising a loose acetabular componen...

Tungsten is incorporated in many industrial goods, military applications and medical devices due to its ability to impart flexibility, strength and conductance to materials. Emerging evidence has questioned the safety of tungsten exposure as studies have demonstrated it can promote tumour formation, induce pulmonary disease and alter immune functio...

Purpose of Review This review article presents the current knowledge on the use of telemedicine and summarizes the literature highlighting the advantages and limitations of this technology in the field of orthopedic surgery during the COVID-19 pandemic and beyond. Recent Findings Orthopedic surgery is the surgical specialty that has seen the highe...

Background The Metasul articular interface was a second-generation MoM THA that was introduced as a promising interface with improved manufacturing technology, better clearances and enhanced metal hardness. In December 2001, the manufacturer recalled these implants due to the failure of cup osseointegration. Methods Between 1997 and 2004, 168 cons...

Background: The primary objective of this study was to determine the incidence of symptomatic venous thromboembolism (VTE), including pulmonary embolism (PE) and deep vein thrombosis (DVT), in the hip fracture population. Secondary objectives included determining timing of VTE diagnosis, VTE thromboprophylaxis given, and identifying any factors ass...

Osteoporotic patients being treated with bisphosphonates present an interesting dilemma when removing hardware such as dynamic hip screws “DHS”. In this paper, we describe the case of a 66-year-old osteoporotic patient who was placed on long term bisphosphonate therapy after sustaining an intertrochanteric hip fracture which was stabilized with a D...

Background Lateral and posterior total hip arthroplasty (THA) approaches disrupt muscle function, which could impact gait. The objectives of this study were to compare muscle activation and joint mechanics during gait, and isometric strength between participants after lateral and posterior THA approaches and healthy adults. Methods Participants 1...

Osteoarthritis (OA) is a disease of diarthrodial joints associated with extracellular matrix proteolytic degradation under inflammatory conditions, pain and disability. Currently, there is no therapy to prevent, reverse or modulate the disease course. The present study aimed at evaluating the regenerative potential of Link N (LN) in human OA cartil...

Osteoarthritis (OA) is a degenerative joint disease characterised by a progressive degradation of articular cartilage and underlaying bone and is associated with pain and disability. Currently, there is no medical treatment to reverse or even retard OA. Based on our previous reports, where we establish the repair potential of short Link N (sLN) in...

Objective: The objective was to compare muscle activation and knee mechanics during gait between participants with non-traumatic knee osteoarthritis (OA), post-traumatic knee OA, and healthy adults. Design: Participants with non-traumatic knee OA (n = 22), post-traumatic knee OA (n = 19), and healthy adults (n = 22) completed gait trials for thi...

Impact statement: A thermosensitive chitosan-based hydrogel was developed, which mimics the mechanical properties of the human nucleus pulposus (NP) tissue and provides a suitable environment for seeded NP cells to live and produce glycosaminoglycans. This scaffold is injectable through 25G needle and rapidly gels in vivo at body temperature. It h...

Background: The degeneration of the intervertebral disc (IVD) is characterized by proteolytic degradation of the extracellular matrix, and its repair requires the production of an extracellular matrix with a high proteoglycan-to-collagen ratio characteristic of a nucleus pulposus (NP)-like phenotype in vivo. At the moment, there is no medical trea...

Neurotrophins (NTs) are the major contributors of sensory axonal sprouting, neural survival, regulation of nociceptive sensory neurons, inflammatory hyperalgesia, and neuropathic pain. Intervertebral disc (IVD) cells constitutively express NTs. Their expression is upregulated by proinflammatory cytokines present in the IVD during degeneration, whic...

Background: Simultaneous bilateral total hip arthroplasty (THA) is an attractive option for patients with osteoarthritis as it requires a single anesthetic and hospitalization. Nonetheless, serious concerns remain over the perioperative safety and rate of hospital readmission. The purpose of the present study was to compare the rate of 30-day majo...

This study reports the effects of the iron chelator deferoxamine (DFO) on collagen cleavage, inflammation, and chondrocyte hypertrophy in relation to energy metabolism-related gene expression in osteoarthritic (OA) articular cartilage. Full-depth explants of human OA knee articular cartilage from arthroplasty were cultured with exogenous DFO (1–50...

Link N (DHLSDNYTLDHDRAIH), is a naturally occurring peptide that can stimulate matrix production in vitro, in vivo and in intact ex vivo human intervertebral discs (IVDs). We have recently discovered that annulus fibrosus cells (AF) cells have the ability to proteolytically process Link N resulting in a fragment spanning amino acid residues 1-8 sho...

Background: The rising costs of total knee arthroplasty (TKA) and total hip arthroplasty (THA) have resulted in a substantial economic burden on the U.S. health-care system. Recent efforts to contain these costs have targeted hospital length of stay. However, shorter hospital admissions have raised concerns over possible increases in complications...

The cartilaginous endplates (CEPs) are thin layers of hyaline cartilage found adjacent to intervertebral discs (IVDs). In addition to providing structural support, CEPs regulate nutrient and metabolic exchange in the disc. In IVD pathogenesis, CEP undergoes degeneration and calcification, compromising nutrient availability and disc cell metabolism....

Intervertebral disc (IVD) degeneration is a common cause of low back pain. Testing potential therapeutics in the regeneration of the disc requires the use of model systems. Although several animal models have been developed to investigate IVD degeneration, they are technically challenging to prepare, expensive, present with limitations when perform...

Prostaglandin E2 (PGE2 )-stimulated G-protein coupled receptor (GPCR) activation inhibits pro-fibrotic TGFβ-dependent stimulation of human fibroblast to myofibroblast transition (FMT), though the precise molecular mechanisms are not fully understood. In the present study, we describe the PGE2 -dependent suppression and reversal of TGFβ-induced even...

Introduction Testing potential therapeutics in the regeneration of the disc requires the use of model systems. Although several animal models have been developed to test intervertebral disc (IVD) regeneration, application becomes costly when used as a screening method. The bovine IVD organ culture system offers an inexpensive alternative, however,...

Purpose Although the disc has limited endogenous repair activity, induced repair of disc tissue may be possible by the intradiscal injection of growth factors to stimulate the production of disc matrix. We previously demonstrated that Link N (DHLSDNYTLDHDRAIH), a naturally occurring peptide generated by the N-terminal proteolytic fragmentation of l...

Background: Proponents of navigation in total knee arthroplasty (TKA) report lower rates of systemic embolization and perioperative bleeding compared to conventional TKA given that breeching the intramedullary canal is not required. Methods: We queried the National Surgical Quality Improvement Program to compare perioperative respiratory complic...

Background: Postoperative complications and perioperative transfusions are common after hemiarthroplasty or total hip arthroplasty (THA) and can lead to increased morbidity and mortality. Methods: The National Surgical Quality Improvement Program Database was queried to compare 30-day major complications and perioperative transfusions after femo...

Supplementary Figure. Diagrammatic representation of human femoral head. Black circles indicate the sites of articular cartilage withdrawal from normal knee of control patients.

Background: Reducing hospital stay and unplanned hospital readmission of arthroplasty patients has been a topic of recent interest. The aim of the present study was to query the National Surgical Quality Improvement Program database to compare the length of hospital stay (LOS) and the subsequent 30-day hospital readmission rates in patients underg...

Background: Shorter femoral stems have been increasingly used in total hip arthroplasty. However, there are few clinical studies evaluating the outcomes of these stems and comparing them to their regular-sized counterparts. Methods: Our study provides radiologic and functional outcomes at 5-year mean follow-up of 131 cementless Tri-Lock Bone Pre...

We queried the National Surgical Quality Improvement Program to compare the rate of 30-day readmissions and major complications between simultaneous bilateral and unilateral total knee arthroplasty (TKA). We identified 1771 patients who underwent simultaneous (same-day) bilateral TKA and matched them to a control group of 6790 patients who underwen...

Local inflammation plays a role in the pathophysiology of osteoarthritis (OA) and chemokines exert catabolic effects on articular cartilage either through paracrine and/or autocrine mechanisms. We sought to compare the expression levels of the chemokine (C-C motif) ligand 20 (CCL20) and its chemokine receptor 6 (CCR6) in donor and osteoarthritic (O...

Goals of this study were (1) to determine the 30-day complications after aseptic revision hip arthroplasty (RHA) and aseptic revision knee arthroplasty (RKA) and (2) to identify patient-related risk factors predicting major complications and prolonged hospital stay beyond 7days. The National Surgical Quality Improvement Program (NSQIP) database was...

Introduction Although the disc has limited endogenous repair activity, induced repair of disc tissue may be possible by the intradiscal injection of growth factors to stimulate the production of disc matrix. We previously demonstrated that Link N (DHLSDNYTLDHDRAIH), a naturally occurring peptide generated by the N-terminal proteolytic fragmentation...

Introduction The intervertebral discs (IVDs) are the largest avascular tissues in the body characterized by an abundant extracellular matrix and low cell density, with innervation limited at the most peripheral annular layers. During IVD degeneration, the neurotrophins, nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF), can sti...

Introduction Intervertebral disc (IVD) calcification frequently occurs with age as demonstrated by radiographic analysis of elderly spines and is enhanced in patients with scoliosis. In one study by Chanchairujira K. et al (Spine 2004;230:499–503), the degree of disc degeneration as measured by disc space height was significantly correlated with IV...

Degenerative disc disease (DDD) is a common cause of lower back pain. Calcification of the intervertebral disc (IVD) has been correlated with DDD. The role of IVD calcification in the development DDD is unknown. We noticed an increase in ionic calcium content and expression of the extracellular calcium-sensing receptor (CaSR) in the degenerate disc...

Currently, there are no established treatments to prevent, stop or even retard the degeneration of articular cartilage in osteoarthritis (OA). Biological repair of the degenerating articular cartilage would be preferable to surgery. There is no benign site where autologous chondrocytes can be harvested and used as a cell source for cartilage repair...

The present study aimed to evaluate the mid-term results of the fourth generation of ceramic on ceramic (CC) bearing. Demographics, surgical technique, complications, clinical and radiologic outcomes were analyzed in a series of 133 consecutive CC total hip arthroplasties (THAs) with a newest generation CC bearings to determine if these provide saf...

The aim of this study was to analyze NSQIP (National Surgical Quality Improvement Program) data to better understand the incidence, risk factors, and thirty-day complication rates associated with transfusions in primary total hip and knee arthroplasty. We identified 9362 total hip and 13,662 total knee arthroplasty procedures from the database and...

Corrosion of the head-neck junction of the femoral component in total hip arthroplasty has been associated with symptomatic adverse local tissue reactions, trunion fracture and elevated serum metal ions. An analysis of risk factors and treatment strategies for corrosion at this interface is lacking in the literature. We therefore performed a system...

Periprosthetic femoral nonunion associated with total hip arthroplasty is an infrequent complication1. However, the increasing worldwide incidence of periprosthetic fractures2 is expected to result in a higher number of complications, including fracture nonunion. A periprosthetic fracture around a well-fixed stem (e.g., Vancouver type B1)3 is a dif...

Background: Few studies have compared the effect of different computer navigation systems on postoperative alignment in patients who have had total knee arthroplasty (TKA). We examined 2 computed tomography (CT)-free computer navigation systems by comparing the accuracy of intraoperative measurements to postoperative alignment. Methods: Patients...

In October 2013, the International Combined Orthopaedic Research Societies (ICORS; http://i-cors.org) was founded with inaugural member organisations from the previous Combined Orthopaedic Research Society, which had sponsored combined meetings for more than 2 decades. The ICORS is dedicated to the stimulation of orthopaedic and musculoskeletal res...

The Prostaglandin E2 (PGE2) signaling mechanism within fibroblasts is of growing interest as it has been shown to prevent numerous fibrotic features of fibroblast activation with limited evidence of downstream pathways. In order to understand the mechanisms of fibroblasts producing tremendous amounts of PGE2 with autocrine effects, we apply a strat...

Prostaglandin E2 is a pleiotropic bioactive lipid that controls cytoskeletal alterations, although the precise, G-protein coupled EP receptor signalling mechanisms remain ill defined. We adopted a phosphoproteomic approach to characterize post-receptor downstream signalling substrates using antibodies that selectively recognize and immunoprecipitat...

Introduction Back pain affects a large portion of the population across all ages, and intervertebral disc (IVD) degeneration is its most common cause. Presently, there are no established treatments to prevent, stop, or even retard disc degeneration, and surgery is often the offered option. Previous studies have shown that Link-N can act as a growth...

Several studies have shown that type X collagen (COL X), a marker of late stage chondrocyte hypertrophy, is expressed in mesenchymal stem cells (MSCs) from osteoarthritis (OA) patients. We recently found that Naproxen, but not other nonsteroidal anti-inflammatory drugs (NSAIDs) (Ibuprofen, Celebrex, Diclofenac), can induce type X collagen gene (COL...

Introduction We previously showed that type X collagen, a marker of late stage chondrocyte hypertrophy (associated with endochondral ossification), is constitutively expressed by mesenchymal stem cells (MSCs) from osteoarthritis patients and this may be related to Naproxen (Npx), a nonsteroidal anti-inflammatory drug used for therapy. Hedgehog (HH)...

Consecutive patients that had primary metal-on-metal (MoM) or metal-on-polyethylene (MoP) hip arthroplasty were prospectively enrolled to this study. All operated hips were evaluated with MRI by one radiologist who was blinded to the radiographic findings and clinical symptoms. Three groups of patients were formed: (1) thirteen MoM THRs in 13 patie...

Introduction Link N peptide is the N-terminal region of link protein which stabilizes the interaction between aggrecan and hyaluronan in proteoglycan aggregates. In vivo, during tissue turnover, link protein is subject to proteolytic degradation by stromelysin and gelatinase A and B generating Link N peptide. It has been shown that human Link N (DH...

Back pain affects a large portion of the population across all ages and intervertebral disc (IVD) degeneration is its most implicated common cause. Presently, there are no established treatments to prevent, stop, or even retard disc degeneration, and surgery is often the offered option. Previous studies have shown that Link N can act as a growth fa...

Introduction Although there are different causes of low back pain, intervertebral disc (IVD) degeneration is one of them. In healthy discs, nociceptive nerve fibers and mechanoreceptors penetrate up to the outer annulus fibrosus (AF). In contrast, the endplates are heavily innervated. However, neither the inner AF nor the nucleus pulposus (NP) are...

Introduction Intervertebral disc (IVD) structure changes throughout life ultimately resulting in disc degeneration and back pain. Most of the IVD extracellular matrix alterations are related this degeneration. Fourier transform infrared (FTIR) spectroscopy has been shown to be a powerful tool in the study of molecular changes associated with matrix...

Introduction Back pain is a fairly common problem, which affects a large portion of the population and has an impact on quality of life. Intervertebral disc (IVD) degeneration is one of the most common causes of back pain. Link-N peptide represents the 16 amino acid sequence (DHLSDNYTLDHDRAIH) from the N-terminus of the link protein that stabilizes...

Introduction Link N is a naturally occurring peptide that can stimulate regeneration of the intervertebral disc (IVD). IVD repair can also potentially be enhanced by mesenchymal stem cell (MSC) supplementation to maximize extracellular matrix production. In a previous study, we have shown that Link N can inhibit osteogenesis and increase the chondr...

Introduction Intervertebral discs (IVDs) are virtually avascular tissue relying on the diffusion of nutrients and metabolites from blood vessels in the outer annulus fibrosus, and in the vertebral bodies that partially penetrate the subchondral plate, and terminate at the cartilaginous endplate (CEP). Degeneration of CEP is viewed as a catalyst to...

Introduction: Link N is a naturally occurring peptide that can stimulate proteoglycan synthesis in intervertebral disc (IVD) cells. IVD repair can also potentially be enhanced by mesenchymal stem cell (MSC) supplementation to maximize extracellular matrix production. In a previous study we have shown that Link N can inhibit osteogenesis and increas...

Introduction: Link N is a naturally occurring peptide that can stimulate proteoglycan synthesis in intervertebral disc (IVD) cells. IVD repair can also potentially be enhanced by mesenchymal stem cell (MSC) supplementation to maximize extracellular matrix production. In a previous study we have shown that Link N can inhibit osteogenesis and increas...

Ceramic-on-ceramic articulations have become an attractive option for total hip arthroplasty in young patients. In this study, we retrospectively evaluated the short- to midterm clinical and radiographic results in 51 consecutive patients (61 hips) using the newest generation of ceramic implants. Results obtained in our study showed positive clinic...

Purpose: To establish relationships between quantitative MRI (qMRI) and biomechanical parameters in order to help inform and interpret alterations of human intervertebral discs (IVD) with different grades of degeneration. Materials and methods: The properties of the nucleus pulposus (NP) and annulus fibrosus (AF) of each IVD of 10 lumbar spines...

Intervertebral disc (IVD) degeneration is the most common cause of back pain. Presently there is no medical treatment, leaving surgery as the only offered option. Here we evaluate the potential of Link-N to promote extracellular matrix regeneration in human IVDs. Human disc cells cultured in alginate and intact human discs were exposed to a combina...

The purpose of this study was twofold: first, to determine whether the five-year results of hip resurfacing arthroplasty (HRA) in Canada justified the continued use of HRA; and second, to identify whether greater refinement of patient selection was warranted. This was a retrospective cohort study that involved a review of 2773 HRAs performed betwee...

In degenerative intervertebral discs (IVD), type X collagen (COL X) expression (associated with hypertrophic differentiation) and calcification has been demonstrated. Suppression of COL X expression and calcification during disc degeneration can be therapeutic. In the present study we investigated the potential of human parathyroid hormone 1-34 (PT...