Manjula Bansal

Analysis of surface damage in retrieved carbon fiber-reinforced and plain polyethylene tibial components from posterior stabilized total knee replacements.

The performance of carbon fiber-reinforced ultra-high molecular weight polyethylene was compared with that of plain (non-reinforced) polyethylene on the basis of the damage that was observed on the articulating surfaces of retrieved tibial components of total knee prostheses. Established microscopy techniques for subjectively grading the presence and extent of surface damage and the histological structure of the surrounding tissues were used to evaluate twenty-six carbon fiber-reinforced and twenty plain polyethylene components that had been retrieved after an average of twenty-one months of implantation. All of the tibial components were from the same design of total knee replacement. The two groups of patients from whom the components were retrieved did not differ with regard to weight, the length of time that the component had been implanted, the radiographic position and angular alignment of the component, the original diagnosis, or the reason for removal of the component. The amounts and types of damage that were observed did not differ for the two materials. For both materials, the amount of damage was directly related to the length of time that the component had been implanted. The histological appearance of tissues from the area around the component did not differ for the two materials, except for the presence of fragments of carbon fiber in many of the samples from the areas around carbon fiber-reinforced components.

Effect of proteoglycan removal on solute mobility in articular cartilage

Transport of nutrients, cytokines, pharmacologic agents, and matrix components through articular cartilage is critical for the viability and structural integrity of the tissue. To understand the role of the extracellular matrix in regulating this process, we measured the diffusivity of three uncharged solutes of different molecular size (glucose, MW 180; inulin, MW 5000; dextran, MW 70,000) into intact cartilage and cartilage that had its proteoglycan (PG) component removed. Solute diffusivity was measured by performing transient (nonsteady state) one-dimensional diffusion tests using radiolabelled solutes. Compared to intact cartilage, the diffusivity of glucose was unchanged after PG removal, inulin was unchanged but dextran increased by 1.7 times after 71% PG removal, and both inulin and dextran increased by 1.6 and 2.0 times, respectively, after 93% PG removal. The diffusivities of inulin and dextran were inversely proportional to the PG content. While no change was found in the tissues bulk fluid content, PG depletion resulted in an increase in fluid content in the upper regions of the tissue and a decrease in the lower regions. These results indicate that in intact tissue small uncharged solutes have free mobility through the inter-molecular and intra-molecular PG volumes, larger molecules have limited intra-molecular mobility, and very large molecules are excluded from the intra-molecular space.

The purely epithelioid malignant peripheral nerve sheath tumor

The purely epithelioid malignant peripheral nerve sheath tumor (PNST) is a rare form of PNT possibly first described by McCormack et al. in 1954. This tumor type is distinguishable from the glandular PNT and PNT with differentiated neuroepithelium (medulloepithelioma and neuroepithelioma) and differs from the ordinary epithelioid PNT because of the absence of a spindle cell component typical of malignant PNSTs. The two examples of purely epithelioid malignant PNT we describe arose in the popliteal fossa from the sciatic and tibial nerves of men with no definite evidence of von Recklinghausens neurofibromatosis. Both tumors were partly mucinous, and so closely mimicked carcinoma and a few non-neurogenic myxoid sarcomas histologically that their final classification depended upon proof of a neural origin.

Changes seen in lymph nodes draining the sites of large joint prostheses.

We report the histological findings seen in the lymph nodes draining the sites of large joint prostheses. Two patients underwent multiple prosthetic joint replacements. In one patient, the regional lymph nodes were enlarged during the revision of a total hip prosthesis, and a representative lymph node was resected. The other patient had undergone a pelvic lymph node dissection as part of a staging procedure for prostatic carcinoma. By light microscopy, the lymph nodes from both patients showed markedly dilated nodal sinuses filled with macrophages containing abundant eosinophilic, PAS-positive, granular material. Polarization microscopy revealed needle-like particles within the cytoplasm of the macrophages. We believe that the histological appearance of the lymph nodes represents a florid foreign body reaction to fragments of polyester or polyethylene derived from the articulating surfaces of the joint prostheses and transported to the regional lymph nodes via the lymphatic circulation. Sinus histiocytosis seen in the lymph nodes draining the sites of joint prostheses may resemble, and must be distinguished from, other conditions invoking a sinus pattern of lymphadenopathy, as well from benign and malignant diseases that involve the lymph nodes in a pattern mimicking sinus histiocytosis.

Soft tissue chondromas: diagnosis and differential diagnosis

The authors evaluated three cases of soft tissue chondromas in patients aged 55, 57, and 78 years. Two of the lesions occurred in the foot and one in the hand. All three patients had long histories (over 1 year) of a palpable mass and all three had roentgenograms showing welldemarcated lobulated soft tissue lesions with both central and peripheral calcifications. Recognition of this rare benign chondroid lesion on imaging studies is significant since it may be misinterpreted as an aggressive lesion or a primary synovial abnormality.

Magnetic resonance imaging in diagnosis of transient osteoporosis of the hip.

The results of magnetic resonance (MR) imaging in six patients with transient osteoporosis of the hip were reviewed. Short TR/TE (repetition time/echo time) images demonstrated diffusely decreased signal intensity in the femoral head and intracapsular region of the femoral neck. Increased signal intensity was noted with progressive T2 weighting. Bone biopsies were performed in four patients. Histologic findings were nonspecific and included fat necrosis, marrow edema, increased bone resorption, and reactive bone formation. Repeat MR scans in two patients, performed six and eight months after the initial scans, showed an almost complete return to normal marrow signal. All patients became asymptomatic without bony deformity. In the appropriate clinical setting, MR scanning can aid in the diagnosis of transient osteoporosis as the cause of a painful hip.

Biomechanical Analysis of an Ovine Rotator Cuff Repair via Porous Patch Augmentation in a Chronic Rupture Model

Background Rotator cuff repair is a commonly performed procedure, but many of these repairs fail in the postoperative term. Despite advances in surgical methods to optimize the repair, failure rates still persist clinically, thereby suggesting the need for novel mechanical or biological augmentation strategies. Nonresorbable implants provide an appealing approach because patch materials may confer acute mechanical stability and act as a conductive scaffold for tissue ingrowth at the site of the tendon insertion. Hypothesis The polyurethane scaffold mesh will confer greater biomechanical function relative to a nonaugmented repair after 12 weeks in vivo using a chronic ovine model of rotator cuff repair. Study Design Controlled laboratory study. Methods After development of the chronic rupture model, the tensile failure properties of the nonresorbable mesh-augmented repair (n, 9) were compared with those of a surgical control in an ovine model (n, 8). Results Rotator cuff repair with the scaffold mesh in the chronic model resulted in a significant 74.2% increase in force at failure relative to the nonaugmented surgical control (P = .021). Apparent increases in stiffness (55.4%) and global displacement at failure (21.4%) in the mesh-augmented group relative to nonaugmented controls were not significant (P = .126 and P = .123, respectively). At the study endpoint, the augmented shoulders recovered 37.8% and 40.7% of the force at failure and stiffness, respectively, of intact, nonoperated controls. Conclusion Using the previously described chronic rupture model, this study demonstrated that repair of a chronic tendon tear with the polyurethane scaffold mesh provides greater mechanical strength in the critical healing period than that of traditional suture anchor repair. Clinical Relevance This device could be used to enhance the surgical repair of the rotator cuff and consequently improve long-term clinical outcome.

Osteogenic sarcoma arising in the area of a total hip replacement. A case report.

A sixty-year-old woman who had bilateral superolateral osteoarthroSiS secondary to dysplasia of the hip was seen at The Hospital for Special Surgery in 1979. In 1980, she had a total hip arthroplasty on the left, in which a stainless-steel Charnley femoral component and a high-density polyethylene Charnley cup were used. In 1983, a similar procedure was performed on the right. The patient was seen in July 1988 with a three-week history of increasing pain in the left thigh and buttock, and a mass was palpable medially and anteriorly around the adductor muscles. Radiographs of the left hip showed a femoral periosteal reaction and a sunburst appearance in the area around the stem of the femoral component of the prosthesis. An open biopsy through a lateral approach revealed areas of periosteal reaction with markedly atypical cells, consistent with an anaplastic high-grade osteogenic sarcoma. Two courses of preoperative chemotherapy, spaced two weeks apart, with high-dose methotrexate, cisplatin, and doxorubicin were given. Then, wide en bloc excision of the proximal part of the femur was performed; the femoral nerve was spared. The capsule of the hip was excised, the adductor muscles were detached from their origin, and the psoas muscle was cut intrapelvically. The acetabular cup, which was well fixed, was retained; it showed minimum wear on gross examination. A custom-made cemented replacement for the proximal part of the femur was implanted. Grossly, the specimen consisted of a large, irregular tumor mass, twelve by seven by five centimeters (Fig. 1). The entire tumor was mapped, and it was sectioned serially. Approximately 50 per cent of the tumor was necrotic. Histologically, it was found to consist of markedly pleomorphic cells with abundant osteoid matrix and chondroblastic differentiation; the diagnosis was high-grade anaplastic osteogenic sarcoma (Fig. 2). No cvidence of polymethylmethacrylate or polyethylene debris was noted in any of the sections that were examined. Three areas of tissue were analyzed: the pseudocapsule of the hip joint, in which no tumor was present; tumor tissue from the area adjacent to the femoral neck; and tumor tissue from the area adjacent to the lateral

Osteoporosis and familial idiopathic scoliosis: association with an abnormal alpha 2(I) collagen.

A positive family history is considered a risk factor for osteoporosis (OP) although the genetic or biochemical basis for this relationship remains undefined. Various mutations affecting normal synthesis of type I collagen have been reported in osteogenesis imperfecta (OI), a heritable disorder of connective tissue. Family A, in which the proband and a daughter are afflicted with OP and idiopathic scoliosis was examined for defects in collagen metabolism. Dermal fibroblast cultures were established to investigate de novo collagen synthesis. SDS-PAGE revealed an abnormally migrating alpha 2(I) chain and procollagen in two generations. Examination of the kinetics of type I collagen pC & N-propeptide processing demonstrated a rate 2x control in the proband. The phenotype family A is not OI. It shares features with families B & C, having familial clustering of OP. However, collagen synthesis was not abnormal in family B & C. These data suggest that in family A the alpha 2(I) structural defect may be related to defective skeletal matrix formation.

Cobalt-Alloy Metal Debris in Periarticular Tissues From Total Hip Revision Arthroplasties: Metal Contents and Associated Histologic Findings

To investigate the hypothesis that an association exists between the presence of metallic particulate or ionic debris released from the components of a total hip replacement and the histologic reaction in the surrounding tissues, cobalt, chromium, nickel, and molybdenum levels were measured in periarticular tissue from 22 individuals who had revision surgery. Total tissue content of the four elements (averaged per case) ranged from 2.7 to 250 micrograms of metal per gr of dried tissue (mean, 39 micrograms/gr); however, within each case, the tissue-metal content varied more widely. The highest total tissue-metal contents occurred in cases revised for infection. Fibrosis, histiocytic reaction, hemorrhage, and necrosis were the most frequent histologic findings. Polyethylene and cement particles each appeared in approximately half of all sections, while microscopic metal particles were seen only in tissues from the infected hips. Tissue-metal content did not correlate with the histologic findings, with any of the demographic variables, nor with duration of implantation. Ratios of the individual constituent elements generally reflected the cobalt-chromium alloy composition, suggesting that metal debris was present predominantly as wear particles. Only for tissues with very low metal contents did departures of these ratios indicate the presence of ionic corrosion products. The extremely low metal contents measured in many cement-bone interfacial tissues and the few metal particles found histologically suggest that metal particles may have been less important in inflammatory reaction and loosening than cement or polyethylene particles.(ABSTRACT TRUNCATED AT 250 WORDS)