Massive metallosis due to metal-on-metal impingement in substitutive long-stemmed knee prosthesis

Metallosis and Nonunion: A Case Series and Literature Review

Metallosis, defined as the presence of free metal particles in the tissue, including bone and soft tissue, is a rare phenomenon seen in orthopedic practice. It is more commonly seen in arthroplasty surgeries, but its occurrence in the presence of other metal implants is also well recognized. Multiple hypotheses are suggested to explain the genesis of metallosis, but it is traditionally believed that abnormal contact between the metal surfaces leads to abrasive wear causing the release of metal particles into the surrounding tissue eliciting foreign body reactions from the body's immune system. The consequences can be local effects, which can be asymptomatic soft tissue lesions, or lead to significant osteolysis, tissue necrosis, joint effusion, and large soft tissue masses, causing secondary pathological effects. The systemic distribution of these metal particles can also contribute to the clinical picture. The literature contains multiple case reports of metallosis following arthroplasty surgeries, but there is limited information on metallosis resulting from osteosynthesis of fractures. In this review, we are presenting our experience with a few patients who developed nonunion following the index surgeries and on revision were found to have metallosis as well. It is difficult to postulate whether metallosis was contributory to the nonunion or the other way around or whether the occurrence of nonunion in face of metallosis was a pure coincidence. Additionally, one of our patients had a positive intraoperative culture, further complicating the picture. In addition to the case series, we present a succinct review of the literature on metallosis found in previous studies.

Metallosis after using distal fibular locking plate for lateral malleolar fractures: a retrospective study

INTRODUCTION

Studies regarding the development of metallosis following open reduction and internal fixation (ORIF) of fractures are rarely found in orthopedic literature. The aim of the current study was to assess metallosis following ORIF using distal fibular locking plates to treat distal fibular fractures.

MATERIALS AND METHODS

69 patients who underwent surgery using locking compression plates to treat lateral malleolar fractures, with a minimum 1-year follow-up period and subsequent hardware removal were enrolled in our study. We divided the patients into 2 groups, to compare the complications and demographics: 38 patients, treated with ZPLP plate; 31 patients, treated with other plates.

RESULTS

During 1 year of postoperative follow-up, 20 complications developed: 6 superficial infections at the operative site, 1 case of nonunion, 3 cases of osteitis, 4 cases of hypaesthesia, 2 cases of peripheral neuropathy, and 4 cases of metallosis. No statistical difference was found in the rate of complications when comparing the treatment groups (Mann-Whitney U test, p < .05) except for metallosis. All 4 patients who developed metallosis were treated using a ZPLP plate, and metallosis did not develop at all in patients who underwent surgery using other plates.

CONCLUSION

In our study, metallosis developed more than was previously known, particularly after using LCPs to treat lateral malleolar fractures. Our findings and those in recent publications support the possibility that metallosis can occur not only in patients with arthroplasties, but also in patients with open reduction and internal fixation with LCPs. Surgeons should be aware of such risk of metallosis and be careful to select proper plates for internal fixation.

Metallosis after knee replacement: a review

INTRODUCTION

Although metallosis is a well-known complication after total hip arthroplasty, little is known about this phenomenon after total (TKA) or unicompartmental knee arthroplasty (UKA). The aim of the present work was to review the current knowledge about the reasons and the diagnostic as well as therapeutic management of metallosis after knee arthroplasty.

MATERIALS AND METHODS

A literature search was performed through PubMed until April 2019. Search terms were "metallosis" in combination with "knee", "knee prosthesis", "knee arthroplasty" and "knee replacement", respectively. All publications were analyzed regarding publication year, level of evidence, number of knees/patients treated, type of prosthesis, metallosis cause, time period between primary implantation and metallosis emergence, laboratory examination, treatment, complications and follow up.

RESULTS

A total of 38 studies reporting on a total of 97 knees were identified. 29 studies reported on metallosis after TKA, 8 after UKA, and one study after both procedures. The time period between the primary implantation and metallosis emergence ranged between 6 weeks and 26 years. The most common reason was the failure of a metal-backed patellar component in 40%, followed by implant/structural- and PE failure (wear/dislocation) in 27% and 18% of the cases, respectively. Complete blood cell count, serum chemistry, erythrocyte sedimentation rate or C-reactive protein serum values were not indicative to diagnose metallosis. The diagnosis was confirmed by histopathological analyses and macroscopic evaluation during surgery. Depending on the particular cause various surgical procedures have been performed. Complete prosthesis exchange was the most common one showing no complications in 89.4% of the cases.

CONCLUSIONS

Metallosis after knee arthroplasty is a rare and perhaps underestimated or under published complication. A systematic diagnostic approach is necessary for the timely and correct diagnosis. A thorough debridement as well as a (sub)total synovectomy should be always performed. In cases with a damaged component, a partial/complete prosthesis exchange leads to the best results. Should a malalignment be the cause of the metallosis, then it should be corrected within the revision surgery.

Rupture of the femoral component and severe metallosis of the knee 10 years after unicompartmental knee arthroplasty (UKA): a case report

A case of a 71-year-old man with femoral and tibial osteolysis and severe metallosis of the knee, resulting from abrasive wears of the metal components of a unicompartmental knee arthroplasty, that leaded to the rupture of the femoral component of the prosthesis is reported. An unicompartmental prosthesis, in a varus knee, was implanted in 2007. In March 2017, the patient felt that his knee was becoming increasingly unstable with pain and increasing disability. At clinical evaluation there was an effusion, 110° of flexion and – 10° of extension and a slight instability at the varus/valgus stress tests. BMI was 35. In a CT scan performed in June 2017 no signs of alteration were evident, but an X-Ray performed in January 2018 showed a rupture of the femoral component. A revision surgery was performed in February 2018. At the time of revision surgery, the synovitis and the metallosis were evident. A cemented total knee arthroplasty was performed. Samples of the fluid and surface did not show any bacterial growth. Histological examination confirmed the presence of a massive metallosis. The patient had a satisfactory rehabilitation. According to the literature, metallosis and rupture of the prosthetic components due to polyethylene wear after UKA is a common complication. In our case report the elevated BMI and varus knee accelerated the wear of the polyethylene. The aim of this case report is to enhance how an appropriate diagnosis (clinical and radiographic) and early treatment can lead to a successful result. (www.actabiomedica.it)

Metallosis in cemented titanium alloy total knee arthroplasty without apparent metal-on-metal articulation

BACKGROUND

Metallosis is an uncommon phenomenon observed in late failures of cemented total knee arthroplasty (TKA), and it is rarely seen in the absence of metal-on-metal articulation.

METHODS

We report the case of a TKA patient with cemented titanium-alloy components and a polyethylene patella that was revised for early loosening with intra-operative severe metallosis.

RESULTS

We found that loosening and severe metallosis were associated with methacrylate particle abrasion on titanium alloy surfaces.

CONCLUSION

Serum titanium ion level measurement may be helpful in the workup of a painful TKA with titanium-alloy components in order to establish a diagnosis.

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.

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.

Serum metal ion concentrations in paediatric patients following total knee arthroplasty using megaprostheses

The purpose of this study was to determine the concentrations of cobalt, chromium, and molybdenum in the serum of paediatric tumour patients after fixed hinge total knee arthroplasty. Further, these metal ion levels were compared with serum metal ion levels of patients with other orthopaedic devices such as hip and knee prostheses with metal-on-metal or metal-on-polyethylene articulation to find differences between anatomical locations, abrasion characteristics, and bearing surfaces. After an average follow-up of 108 months (range: 67 to 163) of 11 paediatric patients with fixed hinge total knee arthroplasty, the mean concentrations for Co and Cr were significantly increased while Mo was within the limits compared to the upper values from the reference laboratory. Furthermore, these serum concentrations were significantly higher compared to patients with a standard rotating hinge device (P = 0.002 and P < 0.001) and preoperative controls (P < 0.001). On the other hand, the serum levels of patients following MoM THA or rotating hinge arthroplasty using megaprostheses were higher. Therefore, periodic long-term follow-ups are recommended due to the rising concerns about systemic metal ion exposure in the literature. Upon the occurrence of adverse reactions to metal debris the revision of the fixed hinge implant should be considered.

Severe metallosis following total knee arthroplasty: a case report and review of radiographic signs

Metallosis is an uncommon complication following total knee arthroplasty that leads to osteolysis and implant loosening due to chronic inflammatory reaction. Abrasion between the metallic surfaces of the implant releases metallic debris that interacts with the periprosthetic soft tissues and causes chronic synovitis. Here we present a case of a 65-year-old man who had undergone total knee arthroplasty 10 years ago and developed implant loosening associated with severe metallosis and varus instability. Radiographs show the three typical signs of metallosis: metal-line sign, bubble sign, and cloud sign. This patient was subjected to revision surgery consisting of debridement and primary implant replacement by a hinged endoprosthesis. Knowledge of the typical radiographic and clinical findings of metallosis is important to rapidly diagnose this complication and avoid progressive joint destruction.

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.

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.

Functional, psychosocial and professional outcomes in long-term survivors of lower-extremity osteosarcomas: amputation versus limb salvage

As the number of osteosarcoma survivors increases, the impact of quality of life and function needs to be addressed. Limb salvage is the preferred treatment when patients have treatment options; yet, the questionable long-term durability and complications of prostheses, combined with ambiguous function, leave some doubt regarding the best clinical and surgical options. Comparisons between limb salvage patients, amputees and controls also require further investigation. Amputation would leave the patients with a lifelong requirement for an external prosthetic leg associated with an overall limited walking distance. While artificial limbs are much more sophisticated than those used in the past, phantom limb sensations remain a substantial and unpredictable problem in the amputee. Complications such as stump overgrowth, bleeding, and infection, also require further elucidation. Limb salvage surgery using endoprosthesis, allografts or reconstruction is performed in approximately 85% of patients affected by osteosarcoma located in the middle and/or distal femur. One drawback in limb-salvage surgery in the long-term survivor is that endoprostheses have a limited life span with long-term prosthetic failure. The inherent high rate of reoperation remains a serious problem. Replacing a damaged, infected or severely worn-out arthroplastic joint or its intramedullary stem is difficult, especially in the long-stem cemented endoprostheses used in the 1980s. Limb lengthening procedures in patients who have not reached maturity must also be addressed. Periprosthetic infections, compared to other indications for joint reconstruction, were found to be more frequent in patients treated for neoplastic conditions and their outcome can be devastating, resulting in total loss of joint function, amputation, and systemic complications. Quality of life in terms of function, psychological outcome and endpoint achievements such as marriage and employment apparently do not differ significantly between amputee and nonamputee osteosarcoma survivors. Amputee patients nonetheless appear to have made satisfactory adjustments to their deficits with or without a functional external prosthesis. It also appeared that amputee patients had a similar psychological and quality of life outcome as limb salvage patients. There was no evidence of excessive anxiety or depression or deficits in self-esteem compared with the normal population or matched controls. A number of long-term survivors also achieved high ranking in the professional and commercial work place. These positive aspects should be recognized and emphasized to patients and their parents when discussing the outcome.

Ilizarov method to correct limb length discrepancy after limb-sparing hemipelvectomy

Pelvic resection for a sarcoma in young patients is challenging, with significant functional, psychological, and social implications. We report the case of a 26-year-old former Ewing's sarcoma patient in whom the Ilizarov technique was applied to address 6 cm of leg length discrepancy secondary to internal hemipelvectomy with superomedial dislocation of the right femoral head. Fifteen years after the internal hemipelvectomy, the patient underwent distal femoral and bifocal tibial lengthening using circular frames. The results obtained in this patient underline the usefulness of the Ilizarov treatment to increase the quality of life in long-term survivors of pelvic bone cancer.

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.

Severe metallosis after unicompartmental knee arthroplasty

We report on a case of a patient who had femoral osteolysis and severe metallosis of the knee joint resulting from the secondary abrasive wear of the metal-backed tibial component of a unicompartmental knee arthroplasty due to massive wear of tibial polyethylene. The failure was diagnosed 11 years after implantation. This metallosis affected the intra-articular tissues and the subchondral bone.

Segmental cement extraction system (SEG-CES) and the Ilizarov method in limb salvage procedure after total knee cemented prosthesis removal in a former osteosarcoma patient

Survival of osteosarcoma has greatly improved in the past few decades. Knee prosthesis is a well-recognized limb salvage procedure for osteosarcoma of the distal end of the femur. One drawback is that prostheses have a limited life and prosthetic failure with the inherent high rate of reoperations remains a serious long-term problem for former osteosarcoma patients. The segmental cement extraction system (SEG-CES) is a technique to remove cement in arthroplasty revision, based on a cement-bone interface with a lower strength compared to the old cement-new cement interface. We report the case of a 32-year-old former osteosarcoma patient in whom the SEG-CES was applied to remove a long-stemmed total knee cemented prosthesis. The prosthesis was placed 17 years before for a recurrent telangiectatic osteosarcoma of the left femur. Thirteen years after the prosthesis implantation, the patient complained of knee instability, pain, and complete failure of the extensor apparatus. The extraction of the prosthesis was performed using cylindrical batters of diameter corresponding to the diameter of the axle, two hammer extractors clamping the prosthesis components between two jaws. Extraction of the periprosthetic cement in the femoral and tibial components was done using the SEG-CES technique. The successful prosthesis removal performed in this patient allowed us to perform an external fixation with bone lengthening and reconstruction by the Ilizarov method.