Under-reporting by surgical pathologists in tissue removed during revision surgery for metal-on-metal arthroplasties.

Although adverse local tissue reactions (ALTR) have been reported for metal-on-metal implants (MoM) requiring early revision surgery, no study has looked at the accuracy of surgical pathologists in diagnosing ALTR. This study aims to investigate the accuracy of reporting adverse local tissue reactions in tissue samples following revision surgery from metal-on-metal implants. The authors reviewed histology glass slides as well as the original pathology reports of tissue processed in revision arthroplasties in 23 cases. These samples were microscopically analyzed for tissue necrosis and cystic degeneration, the presence of metal particles, corrosion byproducts, membrane formation, histiocytic cells, lymphocytic cells, and vascular pathology. The authors' findings were then compared to their corresponding original pathology reports. The authors found consistent under-reporting of the tissue findings. Most importantly, 18 samples showed evidence of metal present compared to 2 samples on original pathology reporting. The authors found that 15 samples showed evidence of pathological membranous tissue compared to just 6 on original pathology reporting. While just 3 of the original pathology reports indicated the presence of areas of predominantly lymphocytic inflammatory cells, the authors found 13 examples of such areas. Although ALTR reactions have been described as a sequala of failed MoM, the authors' data suggest that ALTR may occur more frequently than previously described. Under-reported findings of ALTR deprive both the patient and orthopaedic surgeon of important information that can help guide further follow-up.

Macrodystrophia Lipomatosa of the Foot: A Case Report of MRI and Histologic Findings Including Pacinian Corpuscle Abnormalities.

CASE: A 37-year-old man presented with pain and macrodactyly of a toe. Imaging and histology demonstrated findings consistent with macrodystrophia lipomatosa (MDL). We compared our findings with control tissue obtained from an identical site of a fresh-frozen cadaveric foot from the same anatomical site. Pacinian corpuscles (PCs) in the MDL tissue were increased in number, size, and shape compared with the control tissue and demonstrated edematous interstitial lamellae and vacuolar degenerative change. We also document the magnetic resonance imaging findings of the PCs. CONCLUSION: Peculiar abnormalities of PCs in MDL underline nerve damage and may be a contributing factor in the pain associated with this unusual condition.

Fracture of the Neck of a Lateral Flare Femoral Implant in Total Hip Arthroplasty.

We present the case of a 38-year-old man who presented 7 years after primary total hip replacement with a fracture of the neck of a lateral flare femoral stem and catastrophic polyethylene wear. The unique design of the lateral flare hip stem has been shown previously to be associated with accelerated polyethylene wear, whereas the stem remains well fixed. The resultant polyethylene wear results in the harder cobalt chrome head abrading the titanium shell generating metallic debris. This may have resulted in proximal migration of the implant neck into the cup with subsequent neck-cup impingement and implant fracture.

Histological Findings in Six Failed Metal-on-Metal Implants.

Although joint replacement surgery to relieve pain due to osteoarthritis is generally a successful operation, adverse local tissue reactions can occur in hip arthroplasty in patients who receive metal-on-metal (MoM) implants and lead to early failure. This has led to revisions, lawsuits, and manufacturing recalls. An understanding of the pathological process initiated by metal wear debris is essential in clinical surveillance of cases. We retrospectively reviewed six cases of patients who underwent MoM hip arthroplasties and required early revision. Tissue removed at revision surgery was analyzed histologically by two independent reviewers. All six patients (four males, two females) underwent revision hip arthroplasty after early failure. Revision occurred between 18 and 56 months after the index procedure. Four patients received MoM implants from Depuy, one from Stryker, and one from Wright Medical. A consistent array of pathological findings was associated with these failed MoM implants. Beginning with the development of metal debris, a histiocytic response and proliferation occurred with subsequent corrosion product formation. Membranes were formed, many with cellular infiltrates and pseudosynovial linings and often with ulceration and bleeding. The tissue also demonstrated lymphocytosis and perivascular infiltrates with atypical changes of the endothelial lining cells. Our findings document a predictable cascade of harmful local tissue changes initiated by metal debris in failed MoM hip arthroplasties.

Collagen scaffold meniscus implant integration in a canine model: a histological analysis.

In the situation of an irreparable meniscus tear, an implant comparable to a normal meniscus is an attractive option. Using a canine model, we assessed the early and late histologic response to a tissue engineered meniscal collagen scaffold (CS). All animals received bilateral arthrotomies, and all joints receiving the CS had an 80% resection of the meniscus. Animals were sacrificed at 3 and 6 weeks, and 12, 13, and 17 months. The CS/tissue complex and host meniscal rim were sectioned for histologic examination with specific focus on the extracellular matrix, angiogenesis, cellular resorption of the scaffold, scaffold appearance, and CS/Host integration. Early histologic samples (3-6 weeks) revealed active angiogenesis and fibrin clots evolving into cellular granulation type tissue. At 12 months, a mature fibrochondrocytic matrix was depositing with gradations of dissolution and integration of the CS implant. Maturing CS/host integration was observed at 18 months. Active cellular resorption of the implant decreased over time. Four cases showed a mild non-specific chronic inflammation and one additional case showed inflammatory engulfment of the scaffold with giant cells at 3 weeks. No evidence of infection either clinically or histologically was observed at any time point. Overall, this histologic analysis demonstrated the active integration of a meniscal like cartilage into a tissue engineered biological scaffold in a canine model.

The human knee meniscus: a review with special focus on the collagen meniscal implant.

The human knee meniscus is important for the protection of the knee joint from degeneration. Because it is so commonly injured, several methods have been developed to replace damaged meniscal tissue with either transplanted menisci or other synthetic implants. Here we review these different approaches, with a clinical and histological focus on the collagen meniscal implant (CMI or Menaflex), a tissue-engineered bovine collagen product. Clinical trials in patients receiving the CMI have demonstrated good clinical outcomes in follow-ups as long as 10 years. We review the findings of second-look biopsies of implanted CMI constructs; they demonstrate the fibrochondrocytic ingrowth of tissue mimicking a native meniscus. Integration of the CMI to host meniscus is also confirmed. The histologic inflammation occasionally observed around the graft appears to be of little clinical significance. We conclude that tissue-engineered menisci from bovine collagen are safe in the time period examined and that they hold promise for future repair of the meniscus in appropriate individuals.

Giant medial parameniscal cyst in an osteoarthritic knee.

Medial parameniscal cysts of the knee are typically 0.3 to 9 mm in diameter. Few cases of unusually large medial parameniscal cysts have been reported. We describe the treatment of a patient with osteoarthritis of the knee who presented with an extraordinarily large, ipsilateral, medial parameniscal cyst, 10 cm in diameter. We believe this to be the largest medial parameniscal cyst reported in the English literature. Based on the patient's severe tricompartmental arthritis and associated symptoms, total knee arthroplasty (TKA) was indicated with simultaneous excision of the parameniscal cyst. Perioperativley, the cyst was found to have penetrated beyond the menisco-capsular attachments that were adjacent to a degenerative posterior horn horizontal medial meniscal tear. Following excision of the cyst, the mass was measured with surgical tape to be 10x10x5 cm. After complete excision of the parameniscal cyst, TKA was performed. Histological examination confirmed a benign parameniscal synovial cyst. At 2-year follow-up, the patient was ambulating unassisted without difficulty. The wound had completely healed with no evidence of recurrence of the cyst. The patient's range of motion was 0 degrees to 110 degrees with no signs of instability. Our patient's pathology was most significant for the heretofore unseen large size of the paramensical cyst. Open excision of this giant parameniscal cyst followed by TKA was effective in treating the patient's degenerative joint disease and extraordinarily large, painful soft tissue mass.

Neovascularity in chronic posterior tibial tendon insufficiency.

Insufficient posterior tibial tendons in 28 specimens from patients with clinical Stage II or III disease were examined to clarify the etiology of adult-acquired flatfoot deformity. Hematoxylin and eosin and Masson trichrome-stained sections of formalin-fixed tissue were viewed in plain and polarized light. We performed a qualitative analysis for abnormalities in collagen orientation, degree of vascularization, tenocyte cellularity, mucinous change, and chondroid metaplasia. Tendons were divided into three zones: tenosynovial lining cell layer, subtenosynovial lining cell layer, and tendon proper. All tendons showed neovascular infiltration causing collagen fibril disruption; 50% of specimens had diffuse involvement. Increased mucin content and chondroid metaplasia occurred in 28% and 36% of specimens, respectively. The tenosynovial lining cell layer showed hyperplasia in 28% of specimens. The subtenosynovial lining cell layer showed thickening and neovascularization in 79% of specimens, which appeared to be the source for the diffuse neovascular infiltrative process. There is little histopathologic evidence to support an inflammatory etiology to the posterior tibial tendons in acquired-adult flatfoot deformity. Neoangiogenesis, the prominent histologic finding, is consistent with an obscure insult. We postulate that overuse, tension, or stretching may activate the tenosynovial lining cells and incite angiogenesis.

Case Reports: osteosarcoma of the hand: one case and a literature review.

Osteosarcoma of the hand is rare. We present a case report and a literature review that indicates an older median age of onset than conventional osteosarcoma. The predilection for these lesions to manifest in the metacarpophalangeal joints, particularly in the second and third digits, is in contrast to the more symmetrical distribution of metastatic cancer and correlates with the sites of most active growth during development of conventional osteosarcoma.

Bone biopsy as a screening technique for bone bank allograft donation.

The objective of the study was to investigate occult abnormalities in bone bank allograft with the use of histomorphometry that may otherwise go unidentified with current screening techniques. This was a prospective pathology review in which 40 transcortical trephine bone biopsies were taken from the iliac crest of bone donors and examined by light microscopy and semiautomated histomorphometry. Current routine screening techniques for allograft bone donors include history, serology, and culture. Additional screening for unsuspected pathology and for parameters related to metabolic bone disease may predict the effectiveness of the donor bone. Light-microscopic findings showed 1 case suspicious for chronic myeloproliferative disorder, which had otherwise not been detected by standard screening techniques. On histomorphometric analysis, 3 specimens showed severe osteoporosis. In conclusion, iliac crest bone biopsy may need to be considered as an adjunct in screening for both unsuspected hematological disease and metabolic bone disease.

Osteonecrosis of the femoral head in patients infected with HIV: a report of 4 cases and literature review.

It is important for clinicians treating musculoskeletal complaints to be aware of the possibility of the diagnosis of osteonecrosis in HIV-infected patients. It has been suggested in the literature that when a patient is diagnosed as having osteonecrosis with no other apparent risk factors, the patient should be tested for HIV infection. Further work needs to be carried out to determine any association between HIV infection and osteonecrosis of the femoral head before any such guidelines can be suggested.

Ultrastructural features of giant cell tumors in Paget's disease.

Giant cell tumor is a rare complication of Paget's disease. This association is especially notable in patients originating from Avellino, Italy. Many types of evidence point to a viral etiology for Paget's disease and giant cell tumors arising in it. Three patients who had giant cell tumors and Paget's disease were studied. Two of the patients have a connection to Avellino (one was born in Avellino, and one descended from natives of Avellino). Distinctive light microscopic and ultrastructural features common in these three patients were identified. In all three patients, the giant cell tumors had peculiar irregular aggregates of microfilaments of uncertain genesis. The possibility that these reflect viral infection is discussed.

Osteoclast dysfunction in the osteosclerotic variant of renal osteodystrophy.

Six iliac crest bone biopsies were obtained from five patients with renal osteodystrophy and osteosclerotic lesions to investigate the mechanism of osteosclerosis in renal osteodystrophy. Each specimen was prepared in an undecalcified fashion and measured under light microscopy for routine analysis and histomorphometry. Osteoclast resorptive lacunae were estimated by measuring the lacunar length and depth. Histomorphometric studies revealed an increase in all parameters with a mean trabecular bone volume of 66% (normal: 19%-26%), mean trabecular osteoid surface of 71% (normal: 16%-22%), and a mean trabecular osteoid volume of 15% (normal: 1%-2%). In one patient, there was a ten-fold increase over the norm of osteoclasts/mm2 (0.3; normal: 0.02-0.04), whereas the mean width of trabecular bone was twice the norm. In all biopsies, the calculated lacunar area was markedly diminished compared to published controls. These results support the hypothesis that osteoclast function is impaired in patients with renal osteodystrophy.

Ischial bursal chondromatosis.

A right ischial ulcer recurred after 6 months in a 79-year-old man with a history of recent hip fracture and Girdlestone procedure. Soft-tissue calcification was detected radiographically. The mass, hyperplastic bursal tissue with chondroid metaplasia, was excised. Bursal osteochondromatosis is reviewed.