Wear debris from total hip arthroplasty presenting as an intrapelvic mass

Retroperitoneal Approach for Excision of Wear-Debris Pseudotumor: A Case Report

CASE

Pelvic pseudotumors may occur as a reaction to wear-debris after hip arthroplasty and are rarely treated with surgery. We describe an instance in which a pelvic pseudotumor along the iliopsoas muscle tendon sheath was debulked using a retroperitoneal approach in a patient presenting for treatment of a prosthetic hip infection. The patient recovered uneventfully and was ambulatory with a new hip prosthesis at 3 months after procedure.

CONCLUSIONS

Retroperitoneal exposure provided safe, excellent exposure to a wear-debris pelvic pseudotumor in this case.

External iliac vein compression secondary to osteolysis-induced hematoma in total hip arthroplasty

A 62-year-old man with a history of right total hip arthroplasty, who was managed conservatively for moderate osteolysis, presented with acute-onset, painless, significant, and diffuse right lower extremity edema. Initial laboratory markers were negative for infection. Advanced imaging demonstrated a complex extrapelvic fluid mass along the psoas sheath causing compression of the external iliac vein. Intraoperatively, significant hematoma was removed from the iliopsoas sheath, followed by metal head and liner exchange as well as bone grafting of the osteolytic defects adjacent to the hip implant. Postoperative imaging showed adequate decompression, no deep vein thrombosis, and a patent external iliac vein. At 2 weeks, postoperative swelling completely resolved. At 3 months, the patient recovered to normal baseline level and underwent contralateral total hip arthroplasty for symptomatic osteoarthritis.

Intra-abdominal and intra-pelvic complications following operations around the hip: causes and management-a review of the literature

Although successful and well-established procedures, hip operations whether elective or trauma are coupled with a variety of complications. Among the most uncommon complications are injuries to intra-abdominal or intra-pelvic organs which could prove potentially life-threatening. While there are various reports of such injuries in the literature, we aimed to perform a systematic review in order to examine the causes and relationships between intra-abdominal and intra-pelvic complications and the mechanism of injury, the pattern of presentation, identification, the course of management and outcomes. We identified 69 reports describing a total of 84 complications in intra-pelvic and intra-abdominal contents in 75 patients. These involved six major categories, including the intestinal tract, the urinary tract, the genital tract, the vascular system, the viscera and peripheral nerves. The most commonly injured system was the urinary (33.33%), followed by the vascular (29.76%) and the intestinal (22.62%). Among these systems, the most prevalent complications involved injury to the urinary bladder (32.14%), the large intestine (68.42%) and the external iliac artery (44%). The majority of recorded complications were postoperative with 71 incidents in 63 cases (84.52%). In intra-operative complications the most prevalent injury was due to hardware penetration (53.85%), while in postoperative it was due to hardware migration (92.06%). The management of injuries varied widely, with the most common approach being open exploration and direct repair (77.33%). The reported management outcomes included death (8%) and Girdlestone resection (2.67%), while the majority of the patients healed uneventfully (82.67%) owing mostly to immediate intervention. Despite being rare, such complications may still occur in a variety of settings and may subsequently lead to potential life-threatening situations. Thus, in order to avoid catastrophic outcomes we emphasize the need for prompt identification, immediate intervention and a multidisciplinary approach when necessary.

Growth of an intrapelvic pseudotumor associated with a metal-on-metal total hip arthroplasty after revision arthroplasty causing a femoral nerve neuropathy

The development of pseudotumors is not uncommon with metal-on-metal total hip arthroplasty. Pseudotumors that dissect into the retroperitoneal space can cause symptoms of nerve compression. We describe a case of a 53-year-old male with a metal-on-metal total hip arthroplasty who developed mild symptoms of a femoral nerve neuropathy 6 years postoperatively. Revision arthroplasty to a ceramic-on-polyethylene articulation and debridement of the pseudotumor was performed. Postoperatively, the patient's femoral neuropathy progressed and a repeat magnetic resonance imaging showed an increase in size of the pseudotumor despite the removal of the offending metal-on-metal articulation. The patient subsequently underwent a laparoscopic excision of the retroperitoneal pseudotumor. By 17 months post laparoscopic excision of the pseudotumor, the patient's motor deficits resolved, however, sensory deficits persisted in the anteromedial thigh.

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.

Cystic lesion around the hip joint

This article presents a narrative review of cystic lesions around the hip and primarily consists of 5 sections: Radiological examination, prevalence, pathogenesis, symptoms, and treatment. Cystic lesions around the hip are usually asymptomatic but may be observed incidentally on imaging examinations, such as computed tomography and magnetic resonance imaging. Some cysts may enlarge because of various pathological factors, such as trauma, osteoarthritis, rheumatoid arthritis, or total hip arthroplasty (THA), and may become symptomatic because of compression of surrounding structures, including the femoral, obturator, or sciatic nerves, external iliac or common femoral artery, femoral or external iliac vein, sigmoid colon, cecum, small bowel, ureters, and bladder. Treatment for symptomatic cystic lesions around the hip joint includes rest, nonsteroidal anti-inflammatory drug administration, needle aspiration, and surgical excision. Furthermore, when these cysts are associated with osteoarthritis, rheumatoid arthritis, and THA, primary or revision THA surgery will be necessary concurrent with cyst excision. Knowledge of the characteristic clinical appearance of cystic masses around the hip will be useful for determining specific diagnoses and treatments.

Pseudotumor associated with cemented bipolar hemiarthroplasty: an unusual presentation as a granulomatous thigh mass

Although polyethylene wear-induced osteolysis is a common complication of hip arthroplasty, extensile osteolysis developing into a large granulomatous thigh mass at a site distant from the joint is rare. We report a case of a thigh pseudotumor 25 years after cemented bipolar hemiarthroplasty, in which x-rays revealed a radiolucent line around the stem at the proximal site only, not at the diaphysis of the femur. We initially suspected a real tumor because it had a unique appearance, as if the mass resorbed the posterior cortex of the femur, and it was located at a site distant from the proximal osteolytic lesions. We clearly showed the existence of a connection between the thigh mass and the joint space by performing intra-articular injection of contrast medium with continuous pressure. It seemed that polyethylene wear particles were transported distally along the stem-cement interface by fluid pressure, and an osteolytic reaction against polyethylene wear particles had occurred at the posterior middle third of the stem where the cement mantle was nonuniform and polyethylene particles first came into contact with the bone. Our findings suggest that nonuniform cemented prosthesis with osteolysis, even if it is low grade in a limited area, carries the risk of extensile osteolysis with asymptomatic development of an extra-articular granulomatous mass.

Pelvic pseudotumor following total hip arthroplasty - case report

Loosening is a well-known complication of total hip arthroplasty. The accumulation of detritus resulting from mechanical wear forms inflammatory cells that have the function of phagocytizing this debris. Over the long term, these cells may give rise to a local granulomatous reaction. Here, we present a report on a case of pelvic pseudotumor subsequent to total hip arthroplasty, which is considered rare in the literature. The patient was a 48-year-old black man who started to be followed up medically eight months earlier because of uncharacteristic abdominal pains, dysuria and pollakiuria. He had undergone left total hip arthroplasty 17 years previously. Through clinical investigation and complementary examinations, an extra-articular granulomatous mass was diagnosed, constituting a pelvic pseudotumor.

Metal artifact reduction sequence MRI abnormalities occur in metal-on-polyethylene hips

BACKGROUND

To determine the importance of MRI abnormalities in metal-on-metal (MoM) bearings, it is important to understand the baseline features of this diagnostic tool in conventional metal-on-polyethylene (MoP) bearings.

QUESTIONS/PURPOSES

What are the frequency, size, and types of MRI-documented adverse local tissue reactions in asymptomatic patients with MoP bearings?

METHODS

We recruited 50 patients 5 years after a MoP total hip arthroplasty from a pool of patients in our joint registry who had a Harris hip score of >90. To be included, patients had to be without pain and have adequate radiographs. Our data set included 50 asymptomatic patients with MoP bearings who underwent a metal artifact reduction sequence MRI.

RESULTS

MRI abnormalities were seen in 14 of 50 (28%) asymptomatic patients who were studied. Thirteen of the 14 abnormalities were cystic thin-walled lesions with a mean of 18 cm3 (range, 1-79 cm3).

CONCLUSIONS

MRI abnormalities were noted in nearly one-third of asymptomatic patients with MoP bearings. Decisions concerning revision of MoM bearings should not be based on isolated MRI findings because MRI abnormalities are commonly seen regardless of bearing type. A number of factors should determine the need for intervention including pain, mechanical symptoms, abductor weakness, component type, component position, and ion levels as well as MRI findings.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Inflammatory pseudotumor complicated by recurrent dislocations after revision total hip arthroplasty

A 71-year-old female with a history of right total hip arthroplasty presented with an enlarging pseudotumor. Pseudotumor is a known complication following metal-on-metal and metal-on-conventional polyethylene and metal-on-highly cross-linked polyethylene implants. Revision total hip arthroplasty following resection of pseudotumor has resulted in an increase in incidence of postoperative complications. Despite stable implants, these complications arise from the amount of soft tissue damage combined with the loss of tissue support around the resected hip. Our case is a clear example of a major complication, recurrent dislocation, following resection and revision surgery.

[MRI investigations in patients with problems due to metal-on-metal implants]

Until recently, metal-on-metal (MoM) hip implants were commonly used for joint replacement and resurfacings. Their use has rapidly declined following reports of Frühversagen and soft tissue disease caused by the release of metal debris from the prosthesis. Detection of these soft tissue lesions has proven difficult using conventional imaging techniques and blood metal ion tests. Current guidelines recommend the use of imaging modalities including metal artefact reduction sequence (MARS) magnetic resonance imaging (MRI), computed tomography and ultrasound but provide little indication which is best. MARS significantly reduces the susceptibility artefact induced by the presence of metal objects, thereby producing diagnostic quality images that can be shared with other physicians and compared over time. The clinical interpretation of MRI findings of solid pseudotumours and severe muscle atrophy is straightforward: revision is usually recommended. However, the most common MRI findings are of a cystic pseudotumour and minor muscle wasting. In these cases decision-making is difficult and we currently use multi-disciplinary and multi-colleague based meetings to make decisions regarding patient management. This article presents a comparison of imaging modalities and an update on the interpretation of MARS MRI for the investigation of patients with MoM hip implants.The English full-text version of this article is available at Springer Link (under "Supplemental").

Pelvic mass 21 years after total hip arthroplasty

Background. Long-term urologic complications after total hip arthroplasty are rare, and reports in the urologic literature are scant. We present a recent case and review the relevant literature. Case. A 77-year-old man was referred to the urology clinic for a single episode of gross painless hematuria, abnormal urine cytology, and pelvic mass. He had a significant smoking history. Surgical history included right total hip arthroplasty 21 years prior. Results. Pelvic ultrasound revealed a large mass abutting the right bladder wall. Subsequent computed tomography indicated that the mass was extrinsic to the bladder. Results of computed tomography-guided biopsy of the mass were consistent with foreign body granuloma. Surveillance imaging confirmed no growth or progression, and intervention was deferred. Conclusion. Long-term complications of total hip arthroplasty may present with signs and symptoms of urologic disease. Reports in the urologic literature are rare.

Vascular tumor in metal-on-polyethylene THA requiring hemipelvectomy

Total hip arthroplasty with metal-on-polyethylene implants and metal-on-metal articulations have been an area of recent interest. This article describes a patient with a persistent small soft tissue mass on the anterior groin following total hip arthroplasty with negative findings on infection workup, including blood work and aspiration. Subsequent biopsy findings were consistent with organizing thrombus and necrosis. It then developed into an expansile soft tissue groin mass with significant femoral and pelvic bony destruction and soft tissue infiltration. Metallosis, the formation of a pseudocapsule, and aseptic lymphocyte vasculitis-associated lesions have also been an area of interest following adult hip reconstruction. Occasionally, the formation of subsequent lesions make revision surgery impossible to perform due to bony destruction and soft tissue limitations. Although few in number, most studies or cases that have linked metal-on-metal implants to pseudotumors have been treated with revision surgery and replacement of articulating surfaces. This case highlights a metal-on-polyethylene total hip arthroplasty with a mass presenting with pseudotumor-like characteristics. However, final histology demonstrated fibroadipose tissue with fat necrosis and fibrosis, thickened vascular vessels, and diffuse chronic inflammation with lymphocytic infiltrates, which are more consistent with an atypical inflammatory vascular tumor. The current case illustrates treatment difficulties and provides surgical options for when this event occurs. Although aseptic lymphocyte vasculitis-associated lesions have been observed with metal-on-polyethylene articulations, the multiorgan involvement in this case is unique. In this case, radical excision with hemipelvectomy and complex flap closure was a last resort treatment solution that staved off the prospect of patient mortality.

Pseudotumor associated with metal-on-polyethylene total hip arthroplasty

This case report details the presentation, imaging results, and operative findings of a pseudotumor associated with a press-fit metal-on-polyethylene total hip arthroplasty (THA). An 80-year-old man presented approximately 7 years after undergoing THA with worsening right groin and lateral hip pain with an associated proximal thigh mass. Physical examination demonstrated a tender, large anterolateral thigh mass that was also evident on metal artifact reduction sequence magnetic resonance imaging.An exploratory operative procedure revealed extensive tissue necrosis involving nearly the entire hip capsule, short external rotators, and tendinous portion of the gluteus medius muscle. In addition, marked surface corrosion was discovered about the taper at the head-neck junction of the prosthetic femoral component and the trunnion within the femoral head. The press-fit THA components were solidly fixed. The metallic head was replaced with a ceramic component, and the polyethylene liner was exchanged. The patient had complete resolution of his preoperative symptoms but had persistent problems with dislocations.Although reports of pseudotumor and local soft tissue reactions associated with metal-on-metal THAs have become increasingly ubiquitous in the literature, similar reports involving metal-on-polyethylene THA implants are less common.

Pseudotumor presenting as a pelvic mass: a complication of eccentric wear of a metal on polyethylene hip arthroplasty

The term pseudotumor was coined by Pandit et al (J Bone Joint Surg Br. 2008; 90:847) to describe the features of a soft tissue mass, which is neither infective nor malignant, that is found in association with hip arthroplasty. Most previously reported cases have been associated with a metal-on-metal articulation, with the largest series occurring after hip resurfacing. The author describes a patient who developed a pseudotumor secondary to particulate disease arising after polyethylene liner wear that led to a metal-on-metal articulation in conventional hip arthroplasty.

Inflammatory pseudotumor complicating metal-on-highly cross-linked polyethylene total hip arthroplasty

Inflammatory masses or cysts occurring in the pelvis, thigh, and gluteal regions, often mimicking infection, occasionally arise after total hip arthroplasty procedures. Inflammatory pseudotumors comprise a subgroup of these lesions. Pseudotumors have been associated with pain, rashes, instability, neuropathy, and premature loosening of prosthetic components, often leading to early and difficult revision surgery. The association between such pseudotumors and metal-on-metal bearings has led to questions regarding the performance of these bearings in hip arthroplasty. We present a case of pseudotumor requiring revision surgery, which occurred uniquely around a metal-on-highly cross-linked polyethylene bearing.

Management of a pelvic mass following a worn uncemented total hip arthroplasty

Intrapelvic granulomatous masses from polyethylene wear debris can easily be misdiagnosed if orthopaedic etiology is not considered. This article presents the case of a 50 year old woman with history of hip joint trauma and total hip arthroplasty (THA) revisions who presented to her gynecologist with a large intrapelvic cyst. Prolonged use of an indwelling drain and failure to recognize the orthopaedic origin of the mass resulted in articular infection that required an antibiotic spacer and subsequent THA revision. This patient did not have pain or evidence of medial wall defects, but did have a history of trauma, revision arthroplasty and acetabular allograft. In the presence of these findings, wear-induced polyethylene debris should be considered in the differential diagnosis of the pelvic mass.

Wear debris pseudotumor following total knee arthroplasty: a case report

INTRODUCTION

In patients who have undergone a total joint replacement, any mass occurring in or adjacent to the joint needs thorough investigation and a wear debris-induced cyst should be suspected.

CASE PRESENTATION

An 81-year-old man presented with a painful and enlarging mass at the popliteal fossa and calf of his right knee. He had had a total right knee replacement seven years previously. Plain radiographs showed narrowing of the medial compartment. Magnetic resonance imaging showed a cystic lesion at the postero-medial aspect of the knee joint mimicking popliteal cyst or soft tissue sarcoma. Fine needle aspiration was non-diagnostic. A core-needle biopsy showed metallosis. Intraoperative findings revealed massive metallosis related to extensive polyethylene wear, delamination and deformation. Revision knee and patella arthroplasty was carried out after a thorough debridement of the knee joint.

CONCLUSION

Long-term follow-up is critical for patients with total joint replacement for early detection of occult polyethylene wear and prosthesis loosening. In these cases, revision arthroplasty may provide a satisfactory knee function.

Pre-surgical radiologic identification of peri-prosthetic osteolytic lesions around TKRs: a pre-clinical investigation of diagnostic accuracy

BACKGROUND

Emerging longitudinal data appear to demonstrate an alarming trend towards an increasing prevalence of osteolysis-induced mechanical failure, following total knee replacement (TKR). Even with high-quality multi-plane X-rays, accurate pre-surgical evaluation of osteolytic lesions is often difficult. This is likely to have an impact on surgical management and provides reasonable indication for the development of a model allowing more reliable lesion assessment. The aim of this study, using a simulated cadaver model, was to explore the accuracy of rapid spiral computed tomography (CT) examination in the non-invasive evaluation of peri-prosthetic osteolytic lesions, secondary to TKR, and to compare this to conventional X-ray standards.

METHODS

A series of nine volume-occupying defects, simulating osteolytic lesions, were introduced into three human cadaveric knees, adjacent to the TKR implant components. With implants in situ, each knee was imaged using a two-stage conventional plain X-ray series and rapid-acquisition spiral CT. A beam-hardening artefact removal algorithm was employed to improve CT image quality.After random image sorting, 12 radiologists were independently shown the series of plain X-ray images and asked to note the presence, anatomic location and 'size' of osteolytic lesions observed. The same process was repeated separately for review of the CT images. The corresponding X-ray and CT responses were directly compared to elicit any difference in the ability to demonstrate the presence and size of osteolytic lesions.

RESULTS

Access to CT images significantly improved the accuracy of recognition of peri-prosthetic osteolytic lesions when compared to AP and lateral projections alone (P = 0.008) and with the addition of bi-planar oblique X-rays (P = 0.03). No advantage was obtained in accuracy of identification of such lesions through the introduction of the oblique images when compared with the AP and lateral projections alone (P = 0.13)

CONCLUSION

The findings of this study suggest that peri-prosthetic osteolytic lesions can be reliably described non-invasively using a simple, rapid-acquisition CT-based imaging approach. The low sensitivity of conventional X-ray, even with provision of supplementary bi-planar 45 degrees oblique views, suggests a limited role for use in situ for TKR implant screening where peri-prosthetic osteolytic lesions are clinically suspected. In contrast, the accuracy of CT evaluation, linked to its procedural ease and widespread availability, may provide a more accurate way of evaluating osteolysis around TKRs, at routine orthopaedic follow up. These findings have direct clinical relevance, as accurate early recognition and classification of such lesions influences the timing and aggressiveness of surgical and non-operative management strategies, and also the nature and appropriateness of planned implant revision or joint-salvaging osteotomy procedures.

Pelvic pseudotumor: an unusual presentation of an extra-articular granuloma in a well-fixed total hip arthroplasty

A 76-year-old woman developed a pelvic mass and abdominal pain 12 years after cementless total hip arthroplasty. The mass was a cystic granuloma that communicated with the hip joint via a soft tissue herniation under the inguinal ligament. There was no acetabular lysis or defects. The shell and femoral component were well fixed, the polyethylene was worn, and a liner exchange was undertaken. The cyst was debrided, and follow-up computed tomography demonstrated resolution of the granuloma and no recurrence of the cyst. Removal of the source of the particle wear debris via liner exchange or revision surgery combined with cyst debridement via a single incision is recommended.

Distal leg wear debris mass from a rotating hinged knee prosthesis

An 18-year-old woman presented with a gradually increasing distal leg mass 8 years after wide resection for an osteosarcoma and reconstruction of the proximal left tibia with a rotating hinged knee megaprosthesis. Open biopsy of the distal leg mass showed necrobiotic tissue, metallosis, fibroblasts, osteoblasts, histiocytes, and multinucleated giant cells. The patient underwent debridement of the distal leg mass, metallosis, and wear debris surrounding the tibial component, followed by revision of the destructed polyethylene-bearing components. At the latest follow-up, 4 years after the revision surgery, the patient is alive and tumor-free, asymptomatic, and has no clinical or imaging evidence of wear and metallosis.

Electron Microprobe Analysis and Tissue Reaction around Titanium Alloy Spinal Implants

Study Design

A retrospective study of tissue surrounding titanium alloy spinal implants was performed using histological and electron microprobe analysis.

Purpose

To identify the metal debris generated by spinal implants, and then to evaluate the electron microprobe analysis results and the histological response of soft tissue surrounding the spinal implants.

Overview of Literature

Microscopic metal particles from the soft tissue surrounding joint arthroplasty have been shown to activate a macrophage response that leads to bone resorption and increased inflammation. The effect of unintended wear particles in spinal instrumentation remains a clinical concern.

Methods

Ten patients (average age, 51.3 years), 6 men and 4 women, who had undergone previous lumbar fusions using pedicle screw instrumentation and who were now undergoing revision surgery were included in the study. The tissues obtained from the adjacent area of these implants were analyzed by light microscopy, immunohistochemistry and scanning electron microscope. After the removing the spinal implants, the changes of back pain and the spinal fusion were assessed.

Results

There were metal particles in the soft tissue in 7 cases. Histological finding observed mild chronic inflammation surrounding the deposition of the metal particles and the anti Cotrel-Dubousset 68 positive macrophages were observed at tissue adjacent to the metal particles in 5 patients. Scanning electron microscopy of the specimens showed metallic debris within the tissue and mapping of the metallic particles revealed the distribution of titanium in the tissue in 5 cases. Nine patients had successful relief of back pain after removing the spinal implants. Improvement of the back pain may be an association macrophage response rather than the metal particle.

Conclusions

The presence of metallic particles generated from spinal implants may serve as the impetus for a late-onset inflammatory response and late operative site pain.

Case report: a thigh mass resulting from polyethylene wear of a revision total hip arthroplasty

The case of a 60-year-old man who had an enlarging thigh mass seen during a routine 12-year examination of a cementless revision total hip arthroplasty is presented. Aspiration of the mass yielded more than 200 cc of thick yellow fluid. Cytopathologic examination disclosed material consistent with polyethylene wear debris. The porous titanium acetabular and femoral components were not loose. Reoperation was recommended despite minimal symptoms, because the fluid-filled mass recurred after aspiration. At the time of reoperation, the components appeared well fixed and a linerhead exchange was performed. One year after surgery, the mass had not recurred and the patient had minimal symptoms.

Acute sciatic nerve palsy caused by a polyethylene granuloma arising from a well-fixed total knee arthroplasty

We report the presentation of an acute sciatic nerve palsy, arising as a result of an inflammatory mass in the posterior thigh containing polyethylene debris from an adjacent, well-fixed total knee arthroplasty.

Huge pelvic mass secondary to wear debris causing ureteral obstruction

We report an unusual granulomatous reaction of wear debris that produced a huge pelvic mass causing ureteral obstruction. A 72-year-old woman, who received a cemented total hip arthroplasty 30 years ago, was referred to the department of gynecology for examination of a pelvic mass. A computed tomography scan revealed a huge homogenous mass, measuring approximately 20 x 16 x 12 cm, including extensive osteolysis of the left pelvis around the acetabular component. Intravenous pyelogram revealed complete obstruction of the left ureter resulting in hydronephrosis of the left kidney. Histological examination from the biopsy specimen detected polyethylene wear debris in the mass.

Protrusio acetabuli presenting as a complex pelvic mass after total hip arthroplasty

BACKGROUND

The differential diagnosis in an elderly woman with a complex pelvic mass includes benign and malignant diseases.

CASE

A woman in her ninth decade was discovered to have both a breast mass and a pelvic mass at examination. After diagnostic breast biopsy results that confirmed invasive breast carcinoma, pelvic examination and ultrasonography were performed. The ultrasonogram demonstrated a large complex pelvic mass. The patient underwent an exploratory laparotomy at the time of her mastectomy. The pelvic mass was a protrusio acetabuli resulting from a prior right total hip arthroplasty.

CONCLUSION

A complex pelvic mass secondary to protrusio acetabuli is a rare clinical finding.

Ultrastructural analysis of metallic debris and tissue reaction around spinal implants in patients with late operative site pain

STUDY DESIGN

Cross-sectional ultrastructural analysis of metallic debris as well as the tissue reaction surrounding spinal implants in patients with late operative site pain.

OBJECTIVE

To clarify the cause of late operative site pain by the ultrastructural analysis of the byproducts of metallic corrosion as well as the surrounding soft tissues.

SUMMARY OF THE BACKGROUND DATA

Late operative site pain has been identified as the most frequent cause of implant removal. Allergic reaction to metal as well as low-grade infection has been suggested as probable mechanisms.

METHODS

Fourteen spinal implants were removed because of late operative site pain. Tissues obtained from different zones surrounding these implants were analyzed by light microscopy, transmission electron microscopy, and scanning electron microscopy along with electron dispersion radiograph analysis.

RESULTS

No signs of infection were present. Either one of the 2 types of connective tissue (dense or loose) were found to surround the implants. Macrophage counts were most abundant in zone II (around pedicular screws) when compared to other zones (zone I: around the rods; zone III: around the transverse rod connectors). In contrast, particulate debris was more abundant and larger in size in specimens from zone III. Two types of metallic debris were identified. The rusty appearing particles contained mostly iron (Fe), whereas the black appearing particles were rich in chromium (Cr).

CONCLUSION

This study produced useful information regarding the production and distribution of particulate metallic debris around stainless steel spinal implants.

Intrapelvic granuloma formation six years after total hip arthroplasty in a dog

A 9-year-old Golden Retriever that had undergone left total hip arthroplasty 6 years previously was evaluated because of constipation and tenesmus. Abdominal radiography and ultrasonography revealed a large intrapelvic mass that was contiguous with a mass of polymethyl methacrylate that had been extruded through a defect in the medial wall of the acetabulum at the time of total hip arthroplasty. Clinical signs resolved following resection of the mass and associated polymethyl methacrylate from the pelvic canal. Results of histologic examination of the mass were consistent with a diagnosis of foreign body granuloma, most likely secondary to particulate debris. There was no clinical or radiographic evidence of aseptic loosening of the acetabular or femoral components, and the mass may have represented a response to wear debris.

Prosthetic implant associated sarcomas: a case report emphasizing surface evaluation and spectroscopic trace metal analysis

Advances with implantation of synthetic biomaterials in the setting of orthopedic surgery have clearly resulted in improvements in patient outcomes. However, all implants have been shown to have associated risks. For example, ionic and particulate debris from implants have been shown to engage in biological interactions with the native tissue, and have been associated with a wide range of metabolic, bacteriologic, immunologic, and oncogenic effects. The propensity of synthetic biomaterials to undergo degradation, producing an inflammatory reaction or other sequelae, has been well recognized. The use of porous implants, which allow for a greater interface area between native tissue and the prosthesis, may magnify the interaction between biologically active tissue and synthetic devices in some situations, giving rise to new and intriguing issues concerning biocorrosion and biocompatibility. In this article, we report the case of a high-grade conventional osteosarcoma occurring at the site of a modular porous-surfaced titanium and cobalt alloy total hip prosthesis 3 years after device implantation. Detailed spectroscopic trace metal analysis was performed and elevated levels of both vanadium and chromium, but not aluminum, nickel, or titanium were identified in the tumor.