Revision total hip arthroplasty in hip joints with metallosis: a single-center experience with 31 cases

The impact of femoral head size on the wear evolution at contacting surfaces of total hip prostheses: A finite element analysis

Total Hip Arthroplasty has been a revolutionary technique in restoring mobility to patients with damaged hip joints. The introduction of modular components of the hip prosthesis allowed for bespoke solutions based on the requirements of the patient. The femoral stem is designed with a conical trunnion to allow for assembly of different femoral head sizes based on surgical requirements. The femoral head diameters for a metal-on-polyethylene hip prosthesis have typically ranged between 22 mm and 36 mm and are typically manufactured using Cobalt-Chromium alloy. A smaller femoral head diameter is associated with lower wear of the polyethylene, however, there is a higher risk of dislocation. In this study, a finite element model of a standard commercial hip arthroplasty prosthesis was modelled with femoral head diameters ranging from 22 mm to 36 mm to investigate the wear evolution and material loss at both contacting surfaces (acetabular cup and femoral stem trunnion). The finite element model, coupled with a validated in-house wear algorithm modelled a human walking for 10 million steps. The results have shown that as the femoral head size increased, the amount of wear on all contacting surfaces increased. As the femoral head diameter increased from 22 mm to 36 mm, the highly cross-linked polyethylene (XLPE) volumetric wear increased by 61% from 98.6 mm3 to 159.5 mm3 while the femoral head taper surface volumetric wear increased by 21% from 4.18 mm3 to 4.95 mm3. This study has provided an insight into the amount of increased wear as the femoral head size increased which can highlight the life span of these prostheses in the human body.

ACR Appropriateness Criteria® Imaging After Total Hip Arthroplasty

This article reviews evidence for performing various imaging studies in patients with total hip prostheses. Routine follow-up is generally performed with radiography. Radiographs are also usually the initial imaging modality for patients with symptoms related to the prosthesis. Following acute injury with pain, noncontrast CT may add information to radiographic examination regarding the presence and location of a fracture, component stability, and bone stock. Image-guided joint aspiration, noncontrast MRI, and white blood cell scan and sulfur colloid scan of the hip, are usually appropriate studies for patients suspected of having periprosthetic infection. For evaluation of component loosening, wear, and/or osteolysis, noncontrast CT or MRI are usually appropriate studies. Noncontrast MRI is usually appropriate for identifying adverse reaction to metal debris related to metal-on-metal articulations. For assessing patients after hip arthroplasty, who have trochanteric pain and nondiagnostic radiographs, ultrasound, or MRI are usually appropriate studies. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Metallosis in Total Hip Arthroplasty

» Metallosis is a rare but significant complication that can occur after total hip arthroplasty (THA) for a variety of reasons but most commonly in patients with metal-on-metal implants.» It is characterized by the visible staining, necrosis, and fibrosis of the periprosthetic soft tissues, along with the variable presence of aseptic cysts and solid soft tissue masses called pseudotumors secondary to the corrosion and deposition of metal debris.» Metallosis can present with a spectrum of complications ranging from pain and inflammation to more severe symptoms such as osteolysis, soft tissue damage, and pseudotumor formation.» Workup of metallosis includes a clinical evaluation of the patient's symptoms, imaging studies, serum metal-ion levels, and intraoperative visualization of the staining of tissues. Inflammatory markers such as erythrocyte sedimentation rate and C-reactive protein along with intraoperative frozen slice analysis may be useful in certain cases to rule out concurrent periprosthetic joint infection.» Management depends on the severity and extent of the condition; however, revision THA is often required to prevent rapid progression of bone loss and tissue necrosis.

Longitudinal surveillance of serum titanium ion levels in patients with indigenous 3D printed total temporomandibular joint replacement

The purpose of this longitudinal study was to surveil the serum titanium ion levels at various time intervals in patients with indigenous 3D-printed total temporomandibular joint replacement (TMJ TJR). The study was conducted on 11 patients (male: 8; female: 3) who had undergone unilateral or bilateral TMJ TJR. Blood samples were drawn preoperatively (T0), 3 months (T1), 6 months (T2), and 1 year (T3) postoperatively. Data were analyzed and a p value of < 0.05 was considered statistically significant. The mean serum titanium ion levels at T0, T1, T2, and T3 was 9.34 ± 8.70 µg/L (mcg/L), 35.97 ± 20.27 mcg/L, 31.68 ± 17.03 mcg/L, and 47.91 ± 15.47 mcg/L respectively. The mean serum titanium ion levels increased significantly at T1 (p = 0.009), T2 (p = 0.032), and T3 (p = 0.00) interval. There was no significant difference between unilateral and bilateral groups. Serum titanium ion continued to show increased levels till the last follow-up of 1 year. These initial serum titanium ion levels increase is due to the initial wear phase of the prosthesis which manifests over 1 year. Further studies with large sample sizes and long-term follow-ups are required to see the deleterious effect if any on the TMJ TJR.

[Allergic reactions to bioimplants]

BACKGROUND

Bioimplants are used in a variety of ways in otorhinolaryngology, most commonly in facial reconstructive surgery, cochlear implants (CI), bone-anchored hearing aids, and partial/total ossicular replacement prostheses (PORP/TORP), but also for tympanic drainage, laryngeal cannula, voice prostheses after laryngectomy, etc., and in otorhinolaryngology-related procedures as dental implants in dentistry.

METHODS

A literature search was performed to analyze the immunology of allergic reactions to bioimplants and to determine the available evidence by searching Medline, PubMed, and national and international study and guideline registries and the Cochrane Library. Human studies published in the period up to and including 12/2021 were considered.

RESULTS

Based on the international literature and previous experience, a review of allergies to bioimplants in otolaryngology is presented.

CONCLUSION

Otorhinolaryngologists should always consider the possibility of allergic reactions when inserting allogeneic materials, particularly, but not only, when using bioimplants.

A Rare Case of Metallosis Co-occurring With Chronic Prosthetic Joint Infection in Total Hip Arthroplasty

Prosthetic joint infection (PJI) and metallosis are known complications of total hip arthroplasty (THA) and are causes for revision surgeries. Articulating metal surfaces in total hip arthroplasty with corrosion at modular junctions can lead to the release of metal ions that can cause an immune-mediated biological reaction. There are few cases in the literature of both coinciding together. We describe a case of chronic Cutibacertium acnes PJI and metallosis co-occurring in a 64-year-old female after THA with a dual mobility construct. After undergoing uncomplicated left THA through a modified Hardinge approach, the patient dislocated anteriorly after four weeks and required revision of her acetabular component to a less anteverted position. Nine months later, she presented with hip pain and was found to have medial wall fragmentation and cystic changes around the greater trochanter on radiographs, elevated serum cobalt and chromium levels, and a benign noninfected hip aspiration. During her revision procedure, intraoperative histopathology showed over 20 neutrophils per high power field in multiple samples and fluid aspirates demonstrating Gram-positive rods. She was also found to have pseudotumor formation with the erosion of the anterior and posterior capsules with black debris on the femoral stem trunnion and the backside of the modular dual mobility liner. An antibiotic spacer was placed and her cultures grew into C. acnes. She completed six weeks of intravenous ceftriaxone and, during her "drug holiday," she dislocated her spacer and was found to have a lateral femoral diaphyseal stress fracture at the distal end of her spacer. She underwent stage II of her revision, and while the plan was to continue her antibiotics, she had an adverse reaction and was transitioned to oral antibiotics for six months. Due to delayed healing, she underwent additional irrigation and debridement with head and liner exchange. Her wound then healed, and at her one-year final follow-up, she was able to ambulate without pain, and her serum inflammatory and metal ion levels were within normal limits. Concurrent PJI and metallosis from articulating metal interfaces can occur, and a high index of suspicion is necessary to properly manage both conditions.

Catastrophic failure and metallosis of the acetabular component in total hip arthroplasty

Background

To evaluate the clinical features and results of the revision total hip arthroplasties (THA) in patients with catastrophic failures and metallosis.

Methods

Fifteen hips of 14 patients with catastrophic failure and metallosis in hip arthroplasties were evaluated. They were followed for at least 4.2 years after the revision THA. Clinical evaluation was performed using Harris hip score. Osteolysis, loosening or presence of metallosis was evaluated with standard radiographs. Metallosis was evaluated intraoperatively according to the metallosis severity classification.

Results

The mean time from failure until revision surgery was 9.4 years. It was observed that in the primary THA, metal-on-ceramic (MoC), ceramic-on-ceramic (CoC) and metal-on-conventional polyethylene (MoCPE) bearings were used in 1, 3 and 11 hips, respectively. Grade III metallosis was observed in all patients during revision surgeries. The mean Harris hip score increased from 55 points before revision THA to 75 points at the final follow-up. In revision arthroplasty, MoCPE and CoC bearings were used in 13 and 2 hips, respectively. The femoral stem was replaced in 5 hips. All acetabular cups, except that of one hip, were revised.

Conclusions

Revisions of THAs with catastrophic failures and metallosis are quite challenging. Routine follow-up of arthroplasty patients is beneficial to examine for osteolysis, loosening, and asymmetric wear.

Oxidized Zirconium Total Knee Arthroplasty Implant Failure in a Patient With Knee Instability

Oxidized zirconium was introduced as an alternative bearing surface to decrease polyethylene wear and reduce aseptic mechanical failure of hip and knee arthroplasties. Oxidized zirconium combines the strength of a metal with wear properties of ceramic, proposing increased survivorship of implant components, and possible decreased rate of revision. Despite a harder surface than cobalt-chromium, the substrate of zirconium is a softer metal. Although uncommon, prior reports have described accelerated wear and severe metallosis after femoral head dislocation in oxidized zirconium total hip arthroplasty; however, this has not been described in total knee arthroplasty. We report a case of an oxidized zirconium total knee arthroplasty failure in a patient with knee instability. This is the first report of catastrophic failure of an oxidized zirconium total knee arthroplasty implant.

Removal of bent intramedullary nail: Two case reports

INTRODUCTION

The removal of bent intramedullary (IM) nail can become a challenge. Therefore, various methods have been reported for the extraction of nails after femoral refracture. We want to share our successful treatment.

PATIENT CONCERNS

Case 1. A 44-year-old man was admitted to our clinic after falling while playing soccer. He complained severe right thigh pain with a visible deformity of the femur. His medical history revealed a right femoral shaft fracture caused in a traffic accident which had been treated with intramedullary nailing. Case 2. A 27-year-old man, who had suffered a right femur fracture after a motorcycle accident and been treated with an IM nail, presented after falling down the stairs. He had severe right thigh pain without any open wound or neurologic deficit.

DIAGNOSIS

Case 1. Plain radiographs revealed a refracture of the right femoral shaft and a bent IM nail. The initial varus deformity of the nail was 60.1° in the coronal plane. Case 2. The valgus deformity of the nail was 16.1° with an apex-posterior angulation of 34.8° in the sagittal image of plain radiographs.

INTERVENTIONS

Case 1. Initial manual reduction was tried in emergency room. Then, under general anesthesia closed reduction of the fracture and bent IM nail was done. After closed reduction, the nail was straightened and extracted smoothly. Case 2. Closed manipulation was attempted initially. But no difference in the deformity was achieved. Therefore, via skin incision, the bent nail was progressively sectioned with high-speed cutting burr until the nail could be straightened.

OUTCOMES

Case 1. The patient was mobilized with partial-weight bearing assisted with a crutch on postoperative day two. One year after surgery, the fracture union was complete and the patient was pain-free. Case 2. Six months after surgery, the fracture union was complete with sufficient callus formation around the fracture site.

CONCLUSION

There is no gold standard method to remove a bent IM nail. However, since manual reduction to straighten the bent nail causes minimal soft tissue damage, it should be considered first. If it fails, other methods should be attempted, progressing from the minimally invasive technique to more invasive methods.

Postmortem Retrieval Analysis of Metallosis and Periprosthetic Tissue Metal Concentrations in Total Knee Arthroplasty

BACKGROUND

The purpose of this study is to determine the preferred sampling location for tissue analysis in total knee arthroplasty (TKA) and to evaluate metal concentrations, inflammatory cytokines, component damage, and tissue metallosis.

METHODS

Twenty TKA systems were collected at necropsy along with tissue samples from 5 distinct locations. Inductively coupled plasma mass spectrometry (ICP-MS) analysis was performed to determine cobalt (Co), chromium (Cr), and titanium (Ti) concentrations. Synovial fluid cytokine analysis was preformed using a Magnetic Luminex Screening Assay. Femoral components were assesed for damage and tissues were visually scored for metallosis.

RESULTS

The median metal concentrations were 16 ppb for Co, 46 ppb for Cr, and 9.8 ppb for Ti. There was no association between the tissue collection site and the metal concentration for Co (P = .979), Cr (P = .712), or Ti (P = .854). Twelve of 20 of the necropsy-retrieved TKAs had metallosis, but there was no correlation between Co (P = .48), Cr (P = .89), or Ti (P = .60) concentration and metallosis. Increased Co was associated with decreased tumor necrosis factor alpha (ρ = -0.56, P = .01) and interleukin 1 beta (ρ = -0.48, P = .03). Increased Cr was associated with decreased tumor necrosis factor alpha (ρ= -0.47, P = .03), interleukin 6 (ρ= -0.43, P = .04), and macrophage inflammatory protein 3 alpha (ρ= -0.47, P = .03).

CONCLUSION

We observed elevated Co, Cr, and Ti concentrations in tissue from necropsy-retrieved TKA. Our findings did not support the hypothesis that tissue metal concentrations were associated with inflammatory cytokines. The results of this research will be useful for the design of future prospective studies.

Severe metallosis-related osteolysis as a cause of failure after total knee replacement

BACKGROUND

Metallosis is a syndrome of metal-induced synovitis caused by friction between two metal surfaces. In contrast to the hip joint after resurfacing arthroplasty or metal-on-metal (MoM) total hip replacement, metallosis of the knee is extremely rare.

MATERIALS

We describe 4 patients who underwent revision total knee replacement because of disabling pain and implant loosening after a mean time of 21 (range: 13-30) years of knee replacement surgery. They were all females with a mean age of 79 (range: 75-82) years. Septic loosening was excluded through microbiological examination and synovial fluid analysis.

RESULTS

Direct metal-on-metal contact at the tibiofemoral interface was confirmed intraoperatively in all cases. All knees showed severe metallosis with advanced osteolysis and pseudotumor formation. In one knee there was a complete fracture of the tibial tray. All patients had a one-stage revision surgery with implant removal, profound synovectomy and implantation of a constrained modular revision knee system. Long modular stems with offset adapters, wedges and/or blocks were used in all cases.

CONCLUSION

Metallosis-associated osteolysis should be suspected in cases with radiologically evident polyethylene wear after knee replacement. Recognizing that revision arthroplasty is very technically demanding in such cases, surgeons should have a back-up with modular revision components and a ready access to reconstructive options at this revision setting.

Revision Total Wrist Arthroplasty Due to Polyethylene Wear, Metallosis-Induced Carpal Tunnel Syndrome, Distal Ulnar Impingement, and Fourth Carpometacarpal Joint Pain: Case Report and Pitfalls to Avoid

Background: Total wrist arthroplasty (TWA) is indicated to alleviate pain secondary to arthritis while preserving wrist motion. Despite vigilant measures, TWAs are susceptible to complications. The current case illustrates an array of preventable complications which are addressed through operative technique in a revision setting. Case presentation: The patient was a 72-year-old man who presented with chronic pain at the fourth carpometacarpal joint (CMCJ) and distal radioulnar joint with paresthesias in the median nerve distribution. Surgery was undertaken to address the following complications secondary to a previous TWA: impingement of the native distal ulna on the prosthesis, carpal tunnel due to metallosis and polyethylene synovitis, loose carpal component, and prominent screw at the fourth CMCJ. Surgical correction included open carpal tunnel release with extensive flexor tenosynovectomy, distal ulna resection and implant arthroplasty with shortening, revision of carpal component with bone grafting, and shortening of the ulnar screw to avoid crossing the fourth CMCJ. Within 6 months of the procedure, the patient reported resolution of neuropathic symptoms and pain-free motion of the wrist. Discussion: Preventable complications associated with TWA are individually highlighted. In addition, we compare and contrast our approach and surgical technique to current reported literature. Overall, we provide education and guidance to avoid possible TWA pitfalls. Conclusion: With this case report, we hope to increase TWA knowledge with emphasis on the requirements of judicious patient selection, preoperative planning, meticulous surgical technique, and complication awareness for subsequent optimization of wrist function, stability, and durability.

Evidence for Gender-Specific Bone Loss Mechanisms in Periprosthetic Osteolysis

Osteolysis adjacent to total hip replacement (THR) prostheses is a major cause of their eventual failure. Periprosthetic osteolysis is associated with the production of bioactive particles, produced by the wear of articulating prosthesis surfaces. Wear particles invade the periprosthetic tissue, inducing inflammation and bone resorption. Previous studies have shown that osteocytes, the most numerous cell type in mineralised bone, can respond to wear particles of multiple orthopaedic material types. Osteocytes play important roles in bone resorption, regulating bone resorption by osteoclasts and directly through osteocytic osteolysis, also known as perilacunar remodelling. In this study, we perform a histological analysis of bone biopsies obtained from cohorts of male and female patients undergoing either primary THR surgery or revision THR surgery for aseptic loosening. The osteocyte lacunae area (Ot.Lac.Ar) and percentage lacunar area/bone area (%Ot.Lac.Ar/B.Ar) were significantly larger overall in revision THR bone than bone from similar sites in primary THR. Analysis by patient gender showed that increased Ot.Lac.Ar, indicative of increased perilacunar remodelling, was restricted to female revision samples. No significant differences in osteoclast parameters were detectable between the cohorts. These findings suggest previously unrecognised gender-specific mechanisms of bone loss in orthopaedic wear particle-induced osteolysis in humans.

Midterm outcome of fourth-generation ceramic-on-ceramic bearing surfaces in revision total hip arthroplasty

PURPOSE

The purpose of this study is to evaluate the clinical and radiologic outcomes after revision total hip arthroplasty (THA) using fourth-generation ceramic-on-ceramic (CoC) bearing surfaces.

METHODS

A total of 52 revision THAs (28 men and 19 women) using the fourth-generation CoC bearing surfaces were retrospectively evaluated. Both acetabular cup and femoral stem were revised in all cases. The mean follow-up period was 7.3 years (range, 4.0-9.9 years). The clinical results with Harris hip score (HHS), Western Ontario McMaster Osteoarthritis Index (WOMAC), and radiologic outcomes were evaluated.

RESULTS

At the final follow-up examination, the average HHS was 90.4 (range, 67-100). The average WOMAC pain and physical function score were 2.8 (range, 0-12) and 16.4 (range, 0-42), respectively. Complications were observed in 10 hips (19.2%). However, there were no bearing surface-related complications, and no cases of dislocation and squeaking. Retroacetabular pelvic osteolysis without cup loosening was observed in one hip at the final follow-up. However, no hip showed radiographic signs of cup loosening, vertical or horizontal acetabular cup migrations, and changes of inclinations during the follow-up period.

CONCLUSION

Our data showed that clinical and radiologic outcomes after revision THA using fourth-generation CoC bearing were favorable. Hence, revision THA with the use of CoC bearing surfaces can be preferentially considered. Further studies with long-term follow-up data are warranted.

A single centre study of 41 cases on the use of porous tantalum metal implants in acetabular revision surgery

Background

This study aims at investigating cup survival of porous tantalum revision cups and identifies risk factors for failure.

Methods

We retrospectively reviewed 41 patients treated between 2010 and 2012. Main indications were aseptic loosening in 83% and two-stage exchange after periprosthetic joint infection in 17% of cases. Mean follow-up period was 72 months. Femoral megaprostheses were used in 13% of cases. Most defects were classified as Paprosky 3b (29%). Function was assessed using the Harris Hip score.

Results

Aseptic cup survivorship was 80% at 104 months (95% Confidence Interval 67.4–92.4). Overall implant survival was 73%. Major bone loss defects (Paprosky types 2c to 3b) were associated with a significantly higher rate of failure than minor defects (P = 0.002). There were eight cases of aseptic loosening (19.5%) and two of infection (4.9%). Previous surgeries, indication for acetabular revision, patient-related risk factors and use of megaprostheses did not significantly influence implant survival. The Harris Hip Score improved from a median of 40 (Interquartile range 31–45) to 82 (interquartile range 65–88) postoperative (P < 0.0001).

Conclusions

In summary, the use of porous tantalum metal implants in acetabular revision surgery achieves good to excellent short- term and mid-term functional results and an acceptable complication rate relative to the extent of defect and previous surgery. However, one should be aware of potential limitations of the implants in addressing large defects and discontinuity.

Corrosion of Harrington rod in idiopathic scoliosis: long-term effects

PURPOSE

Metal implants have been used to treat adolescent idiopathic scoliosis since the 1960s. Only recently, however, it has the issue of metal-bone breakdown secondary to metal corrosion in situ come to light, raising concerns of possible long-term complications from the resulting metallosis and inflammation of spinal tissues. We present a case of a patient with neurological deficit, pain, and disability with Harrington rod in place for over 30 years, to bring attention to the issue of bio-corrosion of metal implants and its effect on human tissue. We call attention to the need for protocols to better diagnose and treat these patients.

METHODS

We provide a complete review of the history and clinical manifestations as well as serum metal, X-ray, and CT/myelogram test results.

RESULTS

A 52-year-old female with spinal fusion and Harrington rod presents with pain, lymphedema, disability, and neurological deficits including thoracic outlet syndrome, hyperreflexia, peripheral muscle weakness and atrophy, hypertonicity, Raynaud's phenomenon, and balance and gait abnormalities. Serum chromium levels were elevated (26.73 nmol). X-rays showed no evidence of rod breakdown. Serial X-rays can demonstrate subtle corrosive changes but were not available. Adhesive arachnoiditis was diagnosed via CT/myelogram.

CONCLUSION

We hypothesize that bio-corrosion is present in this case and that it is associated with intraspinal metallosis. Trauma secondary to a motor vehicle accident, as well as arachnoiditis, and their possible effects on this case are outlined. Challenges in proper diagnosis and management are discussed.

Metallosis in shoulder arthroplasty: an integrative review of literature

Shoulder arthroplasty has gained popularity as an efficient means of achieving pain relief and improved function in a variety of complex shoulder disorders. Despite promising reports, given the increasing number of shoulder arthroplasty procedures, various causes that may contribute to failure of a well-functioning arthroplasty are being increasingly recognized. One such disastrous condition is metallosis, a subject which has not been much talked off with reference to shoulder arthroplasty. This article besides reviewing the existing literature intends to discuss the possible causes that contribute to metallosis and devise a protocol for its timely diagnosis and management.

Allergy to Surgical Implants

Surgical implants have a wide array of therapeutic uses, most commonly in joint replacements, but also in repair of pes excavatum and spinal disorders, in cardiac devices (stents, patches, pacers, valves), in gynecological implants, and in dentistry. Many of the metals used are immunologically active, as are the methacrylates and epoxies used in conjunction with several of these devices. Allergic responses to surgical components can present atypically as failure of the device, with nonspecific symptoms of localized pain, swelling, warmth, loosening, instability, itching, or burning; localized rash is infrequent. Identification of the specific metal and cement components used in a particular implant can be difficult, but is crucial to guide testing and interpretation of results. Nickel, cobalt, and chromium remain the most common metals implicated in implant failure due to metal sensitization; methacrylate-based cements are also important contributors. This review will provide a guide on how to assess and interpret the clinical history, identify the components used in surgery, test for sensitization, and provide advice on possible solutions. Data on the pathways of metal-induced immune stimulation are included. In this setting, the allergist, the dermatologist, or both have the potential to significantly improve surgical outcomes and patient care.

Metallosis with pseudotumour formation: Long-term complication following cementless total hip replacement in a dog

CASE DESCRIPTION

A 10-year-old female Belgian Teruven dog was presented to our clinic for total hip revision following a diagnosis of implant (cup) failure with metallosis and abdominal pseudotumour formation. The patient had a cementless metal-on-polyethylene total hip replacement performed nine years prior to presentation.

CLINICAL FINDINGS

The clinical findings, including pseudotumour formation locally and at sites distant from the implant and pain associated with the joint replacement, were similar to those described in human patients with this condition. Histopathological, surgical, and radiographic findings additionally supported the diagnosis of metallosis and pseudotumour formation.

TREATMENT AND OUTCOME

Distant site pseudotumours were surgically removed and the total hip replacement was explanted due to poor bone quality. The patient recovered uneventfully and has since resumed normal activity.

CONCLUSION

In veterinary patients with metal-on-polyethylene total hip implants, cup failure leading to metallosis and pseudotumour formation should be considered as a potential cause of ipsilateral hindlimb lameness, intra-pelvic abdominal tumours, or a combination of both. These clinical findings may occur years after total hip replacement surgery.

Bilateral total hip replacement: periprosthetic pseudotumor collections are more prevalent in metal-on-metal implants compared to non-metal-on-metal ones

BACKGROUND

Metal-on-metal (MoM) hip prostheses were shown to have high failure rates including the formation of periprosthetic cystic masses called periprosthetic pseudotumor collections (PPCs).

PURPOSE

To compare MRI prevalence and size of PPCs in patients after bilateral total-hip-replacement (THR) in which at least one hip was replaced by a MoM prosthesis.

MATERIAL AND METHODS

All sequential MRI examinations of patients with bilateral THR in which at least one is MoM (2010-2013) were retrospectively evaluated. MRIs were analyzed separately by two readers for the presence and size of PPCs. These were compared between MoM and non-MoM implants and between patients with unilateral or bilateral-MoM prostheses. Blood metal ion levels were also compared.

RESULTS

Seventy hips of 35 patients (male:female ratio, 9:26; mean age, 64 years; age range, 35-82 years) were assessed. Sixteen patients (45%) underwent bilateral MoM-THRs and 19 (55%) had one MoM and the other non-MoM, yielding 51 MoM THRs and 19 non-MoM THRs. Twenty-eight PPCs were detected in 19 patients (54%): 26 in MoM THRs (51%) and two in non-MoM THRs (10.5%, P = 0.00009). The mean PPC volume in the MoM implants (107 mm(3)) was higher than that of the non-MoM implants (18 mm(3), P = 0.49). Cobalt/chromium blood levels were 78 µg/L/25 µg/L for bilateral MoM THRs and 21 µg/L/10 µg/L for unilateral MoM implants (P = 0.1 and 0.16, respectively).

CONCLUSION

PPCs are more prevalent in MoM THRs compared to non-MoM THRs. Larger PPC volumes and higher blood metal ion levels were detected in patients with bilateral MoM THRs compared to unilateral MoM THRs (P > 0.05).

Severe Periprosthetic Metallosis and Polyethylene Liner Failure Complicating Total Hip Replacement: The Cloud Sign

We present a case of an 85-year-old woman with extensive metallosis of the left hip joint secondary to prosthetic polyethelene liner dislocation and wear. Radiographs demonstrated amorphous cloudy radiodensities surrounding the prosthesis, a feature we have called the “cloud sign.” The presence of amorphous cloudy radiodensities as a radiographic sign of metallosis has not been previously described to our knowledge.

Metallosis: CT findings in a total hip arthroplasty

We report a case of a 50-year-old man with extensive metallosis 20 years after right total hip arthroplasty. CT demonstrated osteolysis and radiodense debris surrounding the right hip joint. Although the radiographic appearance of metallosis has been well documented in the literature, the CT appearance of metallosis after total hip arthroplasty has been only sparsely described.

Metallosis following full thickness wear in total hip arthroplasty

Extreme wear through the metal-backed acetabular cup following total hip arthroplasty is rare, as symptoms such as pain and disability will usually manifest earlier. We present the second reported case of extreme wear in a 78-year-old male patient, who presented 20 years following an uncemented total hip replacement with a 3-year history of hip pain, clicking on ambulation and worsening mobility. Radiographs demonstrated that the femoral head had migrated superolaterally through the polyethylene liner and the acetabular cup, and was articulating with the superior wall of the acetabulum causing bony destruction. Metallic fragments were also evident. A review of the current literature on metallosis suggests that should there be any clinical suspicion, blood metal ion levels are monitored and an MARS-MRI scan performed if indicated. If metallosis is detected, then revision surgery can be attempted at an earlier date, where the procedure is not as technically difficult.

A Specialized Fibular Locking Plate for Lateral Malleolar Fractures

We evaluated the outcomes and complications of a specialized fibular locking plate in the treatment of lateral malleolar fractures. The study included 27 patients (13 males and 14 females; mean age 46, range 16 to 73 years) with a minimum 1-year follow-up period. The study included 9 (33%) isolated lateral malleolar, 6 (23%) bimalleolar, 10 (37%) trimalleolar fractures, and 2 (7%) pilon fractures, all of which were treated using a specialized fibular locking plate for internal fixation. Bony union was monitored, and the patients' objective satisfaction was evaluated using the EQ-5D questionnaire (EuroQol Group). The patients were followed up after 1 year, and bony union was confirmed using a simple radiograph. The EQ-5D median ± standard deviation was 70 ± 15 (range 40 to 90) points at discharge, 80 ± 13 (range 40 to 90) at 6 weeks, 85 ± 11 (range 50 to 90) at 3 months, 90 ± 8 (range 60 to 90) at 6 months, and 90 ± 9 (range 70 to 95) at 1 year. Therefore, the EQ-5D score increased with time. No significant difference was found when stratified by sex or age (Mann-Whitney U test, p < .05). Eight complications (29%) developed: 1 superficial infection at the operative site, 1 case (3%) of osteomyelitis, 2 cases (7%) of an osteochondral lesion of the talus, and 5 cases (19%) of metallosis. A specialized fibular locking plate has the advantages of being an easy procedure, providing good patient satisfaction, and achieving complete bony union in all patients. However, additional complications developed compared with other well-known methods for fibular fracture treatment.

[CT and MRI of hip arthroplasty]

Metal-induced artifacts impair image quality of computed tomography (CT) and magnetic resonance imaging (MRI) in patients with hip prostheses. Due to new developments in metal artifact reduction both methods can now be used for evaluation of a painful hip prosthesis. Iterative reconstruction algorithms and dual-energy scans are among the newer CT techniques for artifact reduction, while slice-encoding for metal artifact correction (SEMAC) and multi-acquisition variable-resonance image combination (MAVRIC) have introduced substantial improvements for MRI. Loosening of the hip prosthesis, osteolysis from small wear particles and pseudotumors in metal-on-metal prostheses are specific pathologies in patients with total hip arthroplasty. Other causes of painful hip prostheses are infections, fractures, tendinopathies, tendon ruptures, muscle and nerve alterations and heterotopic ossifications.

Metallosis following a dual coat porous hydroxyapatite shoulder hemiarthroplasty

We report a case of metallosis following a shoulder hemiarthroplasty with a humeral component resurfacing shoulder replacement.

The result of revision total hip arthroplasty in patients with metallosis following a catastrophic failure of a polyethylene liner

BACKGROUND

Wear cannot be completely prevented after total hip arthroplasty. If severe polyethylene (PE) liner wear develops, the so-called catastrophic failure occurs and metallosis develops. We postulated that longevity of the new implant may be affected after revision surgery for metallosis following a catastrophic failure of a PE liner due to the substantial amount of PE wear particles and infiltration of the metal particles in this catastrophic condition.

METHODS

Twenty-three hips of 23 patients were identified because they showed metallosis during revision total hip arthroplasties performed in Seoul National University Hospital between January 1996 and August 2004. They were followed for at least 6.5 years after the index revision total hip arthroplasty. The clinical and radiological results of revision total hip arthroplasties in these patients were evaluated.

RESULTS

The median Harris hip score increased from 60 points before revision total hip arthroplasties to 90 points at the final follow-up. Osteolysis was detected at an average of 9.3 years after revision total hip arthroplasties in 13 hips and acetabular cup loosening at average 9.8 years after revision total hip arthroplasties in 9 hips. With radiographic evidence of osteolysis and loosening as the end points, the 15-year survival rates were 28.2% and 56.0%, respectively.

CONCLUSIONS

The survival rate of revision total hip arthroplasty in patients with metallosis following a catastrophic failure of a PE liner was low.

Predictivity and fate of metal ion release from metal-on-metal total hip prostheses

Blood metal ion levels in 72 patients with large head metal-on-metal hip arthroplasty were studied to determine the correlation between the values measured in whole blood and urine. Urinary cobalt and chromium levels of 30μg and 21μg, respectively, adjusted to creatinine were found to correspond to the 7μg/l cut-off value that has been accepted in whole blood. Cobalt and chromium levels in whole blood and urine both significantly correlated with increased acetabular component inclination angle over 50 degrees and pain scores. There was no correlation with socket anteversion angle or femoral head diameter. The data support the use of urinary measurement of metal ions adjusted to creatinine to monitor patients with large head metal-on-metal total hip arthroplasty.

Radiographically undetectable periprosthetic osteolysis with ASR implants: the implication of blood metal ions

Patients with ASR implants (resurfacing and large-diameter (XL) metal-on-metal (MoM) total hip arthroplasty), even if asymptomatic and with a stable prosthesis, may present extremely high blood metal ion levels. We report on a consecutive series of fourteen ASR revisions, focusing on osteolysis and their radiographic correspondence and their correlation with blood metal ion levels. At revision, seven hips revealed severe periacetabular osteolysis which was radiographically undetectable in six and asymptomatic in five. Seven hips with no acetabular osteolysis had significantly lower serum Cr and Co ion concentrations (respectively 25.2, 41.1 μg/l) compared to the seven hips with severe acetabular bone loss (respectively 70.1, 147.0 μg/l). Elevated blood metal ion levels should be considered as a warning of undetectable and ongoing periprosthetic osteolysis in asymptomatic patients with ASR prosthesis.

Neurotoxicology: Five new things

Neurotoxic disease can mimic many common neurologic disease states, including parkinsonism, myelopathy, neuropathy, and encephalopathy. Accurate diagnosis and appropriate treatment may result in a favorable outcome. This review highlights 5 areas of neurotoxicology for which there is an emerging understanding of disease processes or patterns of exposure, including 3 specific metal toxicities (manganism, zinc-induced copper deficiency, and cobalt-chromium neuropathy). Toxin-induced posterior reversible encephalopathy syndrome is more widely recognized and reported in association with an ever-growing list of drugs. Two new categories of street drugs, synthetic cathinones and cannabinoids, have been identified as public health threats due to their popularity, availability, and severity of toxicity.

Metal-on-metal total hip arthroplasty: do symptoms correlate with MR imaging findings?

PURPOSE

To determine the prevalence of magnetic resonance (MR) imaging abnormalities after metal-on-metal total hip arthroplasty and to determine whether presence of symptoms correlates with findings at MR imaging.

MATERIALS AND METHODS

This HIPAA-compliant study was approved by the institutional review board, and informed consent was waived. MR imaging was performed with conventional sequences and a 1.5-T clinical imager in 192 hips (174 patients) evaluated during a 15-month period. Two observers retrospectively reviewed the images for the presence and size of pseudotumor, communication with the pseudocapsule, wall thickness, synovial hypertrophy, compartmentalization, solid components, foci of wall susceptibility, osteolysis, bone marrow edema, abductor muscle or tendon abnormality, and Anderson MR grade (normal, infection, or varying severity of metal-on-metal disease). These findings were compared between asymptomatic and symptomatic patients by using the Fisher exact test or the Wilcoxon-Mann-Whitney test, as appropriate.

RESULTS

Prevalence of pseudotumors per patient and per hip was 69% (120 of 174 patients, 132 of 192 hips). Bone marrow edema (present in six asymptomatic patients and 19 patients with pain, P < .01) and tendon tearing (present in five asymptomatic patients and 13 patients with pain, P < .05) were predictors of pain. Presence of symptoms was not correlated with presence (P = .4151) or size of pseudotumors. Anderson MR grade binarized into normal versus abnormal showed moderate agreement between readers (κ = 0.439) but was also not correlated with symptoms (P = .6648).

CONCLUSION

The presence of bone marrow edema and abductor tendon tears but not the presence or size of pseudotumor was associated with patient pain.

Cutaneous manifestation of metallosis in a metal-on-metal total hip arthroplasty after acetabular liner dissociation

In this case report, we describe a cutaneous manifestation of extensive metallosis in a patient 4 months post-metal-on-metal total hip arthroplasty with a Pinnacle cup with dissociation of the liner from the shell and resultant stripe burnishing of the shell and notch wear of the femoral neck. Dissociation of a metal liner has not been previously reported with this implant. Cutaneous metallosis has only been reported once in the literature. Clinicians should heighten their suspicion for metallosis secondary to hardware failure when encountering patients with skin discoloration in the setting of a painful and poorly functioning hip arthroplasty. In patients with failure of a metal-on-metal prosthesis with a modular metal liner in the acetabular component, liner dissociation must be considered.

Catastrophic fracture of a stable metal acetabular component

Various modes of failure of primary and revision total hip arthroplasty have been well documented in the literature over the past 30 years. Concerns over polyethylene wear, osteolysis, and hypersensitivity reactions leading to component loosening and early revision have been evaluated and reported in the literature. Routine follow-up is important to monitor for postoperative issues that might lead to the subsequent need for revision.This article describes a case of a 64-year-old man who initially presented 11 years prior with an intertrochanteric fracture, which failed secondary to varus alignment and femoral head osteonecrosis. The fixation was converted to a total hip replacement using the S-ROM system (DePuy, Warsaw, Indiana). Subsequently, the patient was lost to follow-up after primary total hip arthroplasty and presented with a catastrophic fracture of the metal acetabular cup system. The failure was suggested by clinical presentation and confirmed by imaging studies showing a fractured acetabular shell with femoral head prosthesis resting in the superolateral ileum. The contributing factors that resulted in mechanical failure were polyethylene wear and component fracture. The acetabular component was revised with an in-growth cementless trabecular metal multihole cup (Zimmer, Warsaw, Indiana) with bone grafting of acetabular defects.Routine assessments help educate patients and allow careful monitoring by physicians while establishing a radiographic timeline for the identification, progression, or lack of postoperative complications.

Catastrophic failure of a metal-on-metal total hip arthroplasty secondary to metal inlay dissociation

Metal-on-metal bearing surfaces in total hip arthroplasty have been recently shown to have acceptable survivorship properties (J Bone Joint Surg Am. 2006;88:1183; J Bone Joint Surg Am. 2006;88:1173), and they have certain advantages and disadvantages when compared to conventional metal-on-polyethylene bearing surfaces. Like traditional metal-on-polyethylene bearings, these metal-on-metal implants may also suffer from catastrophic failure. This case report represents an unusual situation in a 57-year-old man in which dissociation of a metal inlay in a metal-on-metal total hip arthroplasty resulted in articulation of the inferior aspect of the inlay with the femoral neck, leading to femoral neck notching, extensive periprosthetic soft tissue metallosis, osteolysis, and subsequent prosthetic catastrophic failure.

Metallosis following Knee Arthroplasty: A Histological and Immunohistochemical Study

Metallosis represents a rare and severe complication of knee replacement surgery. It is caused by the infiltration and accumulation of metallic debris into the peri-prosthetic structures, deriving from friction between metallic prosthetic components. In knee arthroplasty, this event generally occurs as a result of polyethylene wear of the tibial or metal-back patellar component. The real incidence of metallosis is still unknown, although it seems to be more frequent in hip than in knee arthroplasty. The metallic debris induces a massive release of cytokines from inflammatory cells, making a revision necessary whenever osteolysis and loosening of the prosthesis occur. We report four patients who underwent revision of their knee arthroplasty because of severe metallosis. In one of these patients, polyethylene wear had determined friction between the metal-back patellar component and the anterior portion of the femoral component. In the remaining three cases, metallosis was caused by friction between the femoral and tibial prosthetic metal surfaces, resulting from full-thickness wear of the tibial polyethylene. T lymphocytes were activated by metal particles present in periprosthetic membranes. In all patients, one-stage revision was necessary, with rapid pain disappearance and a complete functional recovery of the knee joint.

Metallosis and Metal-Induced Synovitis Following Total Knee Arthroplasty: Review of Radiographic and CT Findings

Metallosis and metal-induced synovitis are well-recognized complications of metal-backed polyethylene joint prostheses and have been frequently described in the orthopedic surgery literature; however, relatively fewer articles discussing the radiologic aspects of this complication have been published. To illustrate the importance of radiologic findings in the diagnosis and management of these patients, we present a case of metallosis and metal-induced synovitis complicating two revisions of a total knee arthroplasty, caused by polyethylene liner wear and dissociation of the polyethylene liner from the metal-backed patellar prosthesis. Specific attention is given to reviewing signs that aid in diagnosis, such as the "bubble sign," "cloud sign," and "metal-line signs."

Severe metallosis after total elbow arthroplasty-a case report

We present a case of severe metallosis after total elbow arthroplasty in a female patient presenting with manifestations resembling a septic loosening. We discuss the clinical and the operative findings as well as the outcome of this uncommon complication. A review of the literature regarding the pathogenesis, radiographic appearance, and management of metallosis in prosthetic joints is presented.

Third-generation ceramic-on-ceramic bearing surfaces in revision total hip arthroplasty

With an increase of revision total hip arthroplasty (THA), the choice of bearing surface becomes more important. Wear debris by conventional metal-on-polyethylene articulations may cause extensive osteolysis, especially in young patients. We analyzed the clinical and radiographic outcomes after revision THA using third-generation ceramic-on-ceramic bearing surfaces in 42 hips. The mean age of the patients was 48.8 years (32-59 years), and the mean duration of follow-up monitoring was 5.4 years (3.2-8.0 years). At final follow-up examination, the average Harris Hip Score was 91.3. Although minor complications were observed in 6 hips (14.3%), no hips required additional revision surgery. No hip showed radiolucent lines, acetabular cup migration, or osteolysis. Our data show that clinical and radiographic outcomes after revision THA using third-generation ceramic-on-ceramic bearing surfaces are favorable. Ceramic-on-ceramic bearing surfaces can be preferentially considered for revision THA, especially in young patients. Further studies with long-term follow-up data are warranted.

Peri-implant and systemic release of metallic elements following insertion of a mandibular modular endoprosthesis in Macaca fascicularis

The aim of this study was to assess the release of metal elements from a Ti6Al4V modular endoprosthesis for mandibular reconstruction. Ten monkeys were included, seven of the animals had an endoprosthesis inserted and three served as controls. Mucosa, regional lymph nodes and distant organs, were assessed after the implant had been in place for 12 months, using light (LM) and transmission electron microscopy (TEM) and inductively coupled plasma optical emission spectroscopy (ICP). Blood was also drawn from all animals for elemental analysis using ICP. LM and TEM evaluation showed no detectable metal particles in the mucosa surrounding the endoprosthesis, nor in the regional lymph nodes and distant organs. Blood analysis revealed that titanium and vanadium were detectable in comparable amounts in the test (Ti: 1.63+/-0.54, Va: 0.42+/-0.08) as well as in the control group (Ti: 2.07+/-0.55, Va: 0.37+/-0.07). The amount of aluminum appeared to be higher in the control group (31.77+/-11.67) compared with the test group (20.41+/-9.13), but this difference was not statistically significant. ICP showed that no titanium, vanadium or aluminum was detectable in the mucosa surrounding the endoprosthesis. In addition, no titanium and vanadium were found in the lymph nodes and distant organs using ICP. On the other hand, using ICP, the aluminum content was found to be higher in the right regional lymph nodes and all examined distant organs as compared to the control group (lymph nodes: 11.55+/-22.15 vs. 0.36+/-0.61, lung: 6.24+/-11.28 vs. 1.40+/-2.15, liver: 1.66+/-0.99 vs. 0, kidney: 15.69+/-24.88 vs 0, spleen: 2.75+/-3.09 vs. 0.49+/-0.43). However, only for the kidney and liver the higher amount of aluminum was statistically significant. In conclusion, this study quantified the release of only aluminum in lymph nodes and distant organs, when using a modular endoprosthesis made of Ti-6Al-4V for mandibular reconstruction.

The natural history of metallosis from catastrophic failure of a polyethylene liner in a total hip

We report on a case of metallosis initially presumed to be heterotopic ossification based on radiologic findings. A 68-year-old man with a total hip arthroplasty experienced failure of the polyethylene liner, resulting in articulation of the ceramic head with the titanium acetabular shell. During revision surgery, extensive metallic debris was evident macroscopically throughout the periprosthetic tissue and was confirmed histologically to be metallosis.

Chromium, cobalt and titanium metallosis involving a Nottingham shoulder replacement

Metallosis after shoulder replacement has not previously been described in the literature. We report a patient who developed extensive metallosis after implantation of an uncemented Nottingham shoulder replacement. He underwent a revision procedure. Examination of the retrieved prosthesis showed that the titanium porous coating was separating from the humeral stem and becoming embedded in the ultra-high-molecular-weight polyethylene glenoid component, resulting in abrasive wear of the humeral component. There was metallosis despite exchange of the modular humeral head. Both components had to be exchanged to resolve the problem.

The imaging appearances of metallosis

Metallosis is an uncommon condition in which there is infiltration of periprosthetic soft tissues and bone by metallic debris resulting from wear of joint arthroplasties. It is often associated with significant osteolysis; therefore the identification of metallosis is an indication for revision arthroplasty. The radiographic, CT and MRI features of metallosis in a 63-year-old man who presented 16 years post-arthroplasty are described in this case report.

Revision total hip arthroplasty for pelvic osteolysis with well-fixed cementless cup

Treatment of pelvic osteolysis after total hip arthroplasty (THA) remains controversial. Clinical and radiographic outcomes of revision THA were evaluated in 62 hips with pelvic osteolysis and well-fixed cementless cups. The patients' mean age was 50.9 years, and the mean interval from primary to revision THA was 9.7 years. For revision, cementless cups were used in 51 hips, and cemented cups in 11 with acetabular reinforcement rings in 9. The mean duration of follow-up after revision THA was 5.9 years (range, 3.0-9.7 years). At final follow-up, the average Harris Hip Score was 92.4, and there was no radiographic complication except for 1 with change of inclination. Revision THA for pelvic osteolysis with well-fixed cementless cups showed favorable outcomes, and it can be preferentially used in young patients.