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Biomedical subjects

Javad Parvizi

Publications and source records attributed to Javad Parvizi.

At least 37 records · Page 2Linked to original sources
PubMed2006

Revision hip arthroplasty for late instability secondary to polyethylene wear.

We evaluated the outcome of revision arthroplasty for polyethylene wear presenting as late dislocation. The computerized databases at two institutions were reviewed to identify all patients presenting with first time dislocation five or more years after total hip arthroplasty. Records and radiographs were then evaluated, and patients whose late dislocation occurred in the presence of greater than two millimeters of polyethylene liner wear with no other etiology for dislocation were identified. There were 22 patients with a mean age of 57.8 years at primary procedure. The average time from initial arthroplasty to dislocation was 9.0 years. Revision surgery to address polyethylene wear and instability was performed at a mean of 11.1 years (range 5.8 to 23 years). Revision surgery restored stability to eighteen patients (eighty-two percent). Polyethylene wear can and is associated with late dislocation after hip arthroplasty. Exchange of polyethylene lining of a metal backed implant or revision of the all polyethylene acetabular component can successfully address late instability in the majority of patients.

Adult↗
PubMed2006

Revision total hip arthroplasty: the patient's perspective.

We evaluated a consecutive series of patients followed for at least 1 year after revision total hip arthroplasty. We surveyed 488 patients treated at three referral centers from 1998 to 2002. An experienced medical interviewer contacted patients and rated their degree of satisfaction with the original and revision arthroplasties, the reason of original arthroplasty failure, and their expectations for revision arthroplasty longevity. Surveys were completed on 320 of the 488 patients (66%). A member of the research team reviewed patients' operative reports, clinical records, and radiographs to determine the diagnosis at revision, procedure performed, and the most likely cause of failure. Patient satisfaction with the primary procedure was directly related to the time to revision. Most patients (214 of 320; 67%) expected their revision to last longer than their primary arthroplasty regardless of revision diagnosis or how long the primary procedure lasted before revision. The surgeons' failure assessments agreed with the patients' failure assessments only 36% of the time. Although the majority of patients (262 of 320; 82%) were satisfied with the results of the revision procedure, most did not agree with their surgeon as to why the original arthroplasty failed, and most had unrealistic expectations regarding revision longevity.

Arthroplasty, Replacement, Hip↗
PubMed2006

2006 Otto Aufranc Award Paper: significance of in vivo degradation for polyethylene in total hip arthroplasty.

Our research group developed an implant retrieval program to study in vivo degradation of polyethylene. We now have evidence to support our hypothesis that degradation of radiation-sterilized polyethylene occurs in the body for not only historical gamma air sterilized liners, but also for conventional gamma inert sterilized (ArCom) and annealed highly crosslinked polyethylene (Crossfire) liners as well. Our research has also led to the discovery that the most severe manifestations of in vivo oxidation typically occur in regions of the liner experiencing minimal wear, such as the rim of the component, where the body fluids (containing oxidizing species) have access to the polyethylene. Our data from historical, ArCom, and Crossfire retrievals all point to a similar scenario in which the femoral head limits the in vivo oxidation of polyethylene at the bearing surface. Consequently, provided rim impingement does not occur, and the polyethylene locking mechanisms remain relatively isolated from oxidizing fluid, in vivo oxidation does not seem to be clinically important in the first 10 years of implantation for conventional gamma sterilized polyethylene. We conclude that in vivo degradation should be included among the list of potential long-term failure modes for modular polyethylene components for total hip arthroplasty.

Arthroplasty, Replacement, Hip↗
PubMed2006

Surgical management of Paget's disease of bone.

Paget's disease is a chronic nonmetabolic bone disorder that is characterized by increased bone resorption, bone formation, and remodeling. This unbalanced process may lead to osseous deformities, structural weakness, and altered joint biomechanics, all of which can make surgical reconstruction difficult. Although few patients with Paget's disease ever need surgical treatment, successful surgical management of orthopedic manifestations of the disease has improved the quality of life for these patients. Surgical options include corrective osteotomy for long bone deformity, fracture fixation, joint arthroplasty, spinal decompression, and tumor resection. Patients are at increased risk for surgical complications such as blood loss and heterotopic bone formation. Issues relating to the surgical management of patients with Paget's disease such as appropriate preoperative diagnosis, technical challenges of surgery, and strategies to improve the long-term outcome of surgical intervention are discussed.

Biopsy↗
PubMed2006

Diagnosis of periprosthetic infection.

Periprosthetic infections are rare, but there is evidence to suggest that their frequency may be underestimated. No single laboratory test has perfect sensitivity and specificity for diagnosing infection. Most tests have better specificity when they are performed for patients in whom infection is suspected clinically rather than when they are used as screening tests. Screening test results that may suggest the possibility of infection include elevation of the erythrocyte sedimentation rate and/or serum C-reactive protein level more than three months after an arthroplasty. Most serologic tests are difficult to interpret when the patient has an underlying inflammatory arthropathy. Cultures of aspirated joint fluid can be especially helpful for patients who have symptoms suggestive of infection, but their results are best interpreted two weeks after administration of antibiotics has been discontinued. Joint fluid cell counts may also be helpful, but Gram stains of joint fluid have poor sensitivity and specificity. Criteria for diagnosing infection on the basis of frozen sections of implant membranes have not yet been standardized, but in many laboratories more than five neutrophils per high-power field in five or more fields (excluding surface fibrin) has been found to be suggestive of infection. Most polymerase chain reactions that detect the universal 16S rRNA bacterial gene have problems with false-positive results, but combining a universal polymerase chain reaction with subsequent bacterial sequencing can help improve specificity. Polymerase chain reactions can detect necrotic bacteria, so the clinical importance of positive results of this analysis in the absence of other features of infection remains to be determined.

Humans↗
PubMed2006

Uncemented total hip arthroplasty in young adults with osteonecrosis of the femoral head: a comparative study.

BACKGROUND: The outcome of uncemented total hip arthroplasty in patients with osteonecrosis of the femoral head in general, and in young adults in particular, remains largely unknown. This study evaluated the clinical and radiographic results of uncemented total hip arthroplasty in young adults with osteonecrosis of the femoral head and compared these results to those seen in young adults with osteoarthritis. METHODS: Forty-one consecutive patients with osteonecrosis of the femoral head (fifty-two hips) and forty patients with osteoarthritis (fifty-two hips) were treated with an uncemented total hip arthroplasty at our institution. The mean age for the osteonecrosis group was thirty-eight years, and, for the osteoarthritis group, forty-two years. Clinical and radiographic outcomes at a minimum of two years were assessed. RESULTS: At a mean duration of follow-up of three years, the functional improvement was significant in both groups (p < 0.05). The outcome was good to excellent for 94% (forty-nine hips) in the osteonecrosis group and 96% (fifty hips) in the osteoarthritis group. There were two revisions in the osteonecrosis group and one revision in the osteoarthritis group. Survivorship free of revision at the time of the latest follow-up was 96.1% for the osteonecrosis group and 98% for the osteoarthritis group. CONCLUSIONS: The short-term results of cementless total hip arthroplasty in patients with osteonecrosis of the femoral head were encouraging and comparable with the results of a matched group of patients with osteoarthritis. We await further follow-up to see if these promising results hold true. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions to Authors on jbjs.org for a complete description of levels of evidence.

Adolescent↗
PubMed2006

Surgical manifestations of Paget's disease.

Paget's disease is a chronic, nonmetabolic bone disorder characterized by increased bone resorption, bone formation, and remodeling. This unbalanced process may lead to osseous deformities, structural weakness, and altered joint biomechanics, all of which can make surgical reconstruction difficult. Although few patients with Paget's disease require surgical treatment, successful surgical management of severe orthopaedic complications has improved the quality of life for these patients. Surgical options include osteotomy to correct long-bone deformity and arthroplasty to restore altered joint mechanics. Patients are at increased risk for surgical complications, such as blood loss and heterotopic bone formation. Issues relating to the surgical management of patients with Paget's disease include appropriate preoperative diagnosis, technical challenges of surgery, and strategies to improve the long-term outcome of surgical intervention.

Arthroplasty, Replacement, Hip↗
PubMed2006

Nonarthroplasty surgical treatment of hip osteoarthritis.

The two conditions that give rise to osteoarthritis of the hip are dysplasia and nondysplasia. Dysplasia, commonly associated with anterolateral acetabular deficiency, may lead to osteoarthritis in 40% of patients in the United States with this condition. In a distinct category of patients with so-called idiopathic arthritis, there is no apparently identifiable cause for osteoarthritis. There is emerging evidence that subtle morphologic abnormalities around the hip, resulting in femoroacetabular impingement, may often be a contributing factor to osteoarthritis in young patients.

Humans↗
PubMed2006

Surgical treatment of osteonecrosis of the hip.

Various surgical procedures are used in patients with osteonecrosis of the hip. Patients with precollapse of the femoral head are generally treated with head-preserving procedures (core decompression, various bone grafting techniques, and osteotomies), whereas those with collapse of the femoral head and/or arthritis may require arthroplasty. The arthroplasty options available include limited femoral resurfacing arthroplasty, metal-on-metal resurfacing arthroplasty, or total hip replacement. The indications, techniques, and early outcomes of some of these procedures for treatment of osteonecrosis of the hip merit discussion.

Femur Head Necrosis↗
PubMed2006

Criteria used by medical students to rank orthopedic surgery residency programs.

Residency positions orthopedic surgery continue to be highly sought after. There is no published report of the criteria that candidates use to evaluate prospective orthopedic surgery programs. A survey, created to evaluate what these candidates value in a residency program, was sent to all current orthopedic surgery postgraduate year 1 and year 2 residents through their prospective program directors. Responses were analyzed to determine which factors were most and least important in ranking orthopedic surgery residency programs. Early surgical/clinical experience was the most important factor; geography, second most important; program reputation, third most important. Research opportunities were least important; program size, second least important; regional cost of living, third least important. Data from this survey will enable program directors to emphasize their "more desirable" aspects and minimize the "less desirable" in their attempts to attract top candidates. In addition, directors may incorporate these data into their residents' rotation schedule to provide more early surgical experience and a more directed educational program.

Humans↗
PubMed2005

Perioperative morbidity and 30-day mortality after intertrochanteric hip fractures treated by internal fixation or arthroplasty.

The conventional treatment for intertrochanteric hip fracture is open reduction and internal fixation. However, hip arthroplasty is occasionally performed. The objective of this study was to determine the 30-day mortality for patients with intertrochanteric hip fracture treated with open reduction, internal fixation, or hip arthroplasty. The mortality rate for patients treated with arthroplasty at 4.8% (23/478) was slightly, but not significantly, higher than that for patients treated with open reduction and internal fixation at 4.5% (62/1395). However, more of the patients in the arthroplasty group exhibited serious intraoperative cardiorespiratory disturbances (62% vs 22%) and died in the hospital (77% vs 35%) when compared with the patients in the open reduction and internal fixation group. Although the incidence of 30-day mortality in these groups was not significantly different, the patients in the arthroplasty group were more likely to have a complicated intraoperative course and die in the hospital.

Adult↗
PubMed2005

Mechanical properties of retrieved highly cross-linked crossfire liners after short-term implantation.

This study reports on detailed analyses of retrieved, annealed cross-linked liners. Twelve cross-linked liners (Crossfire, Stryker Orthopaedics, Mahwah, NJ) of the same Omnifit design were retrieved at revision surgery by one institution after an average 1.9 years (0.02-4.8 years) in vivo. In each case, the revision surgery was performed for reasons unrelated to wear. The mechanical properties and extent of oxidation of all inserts were characterized using a standard small punch test and measurement of the oxidation index. Results indicated that there was no association between implantation time and either mechanical properties or extent of oxidation for the inserts near the worn bearing surface. Slight variation in properties was observed as a function of sampling location, with the properties near the unworn surface displaying the greatest relative variability. We conclude that the variability in polyethylene properties observed in this small study was not clinically significant for these short-term-implanted, annealed cross-linked liners.

Adult↗
PubMed2005

Pulsed low-intensity ultrasound for fracture healing.

A large body of evidence confirms the stimulatory effect of pulsed low-intensity ultrasound on fresh fractures, nonunions, and other osseous defects such as osteotomies. This article presents the findings of some of these studies and briefly discusses our current understanding of its molecular mechanisms.

Animals↗
PubMed2005

Failure to resurface the patella during total knee arthroplasty may result in more knee pain and secondary surgery.

UNLABELLED: Resurfacing the patella during primary total knee arthroplasty is controversial. The objective of this meta-analysis was to evaluate the outcome of total knee arthroplasty with or without resurfacing of the patella with particular attention to patient satisfaction, incidence of anterior knee pain, patellar complications, and the need for secondary operations. Computerized databases were searched for citations and published randomized clinical trials relevant to patellar resurfacing from 1966-2003. Of 158 citations identified as related to patellar resurfacing during total knee arthroplasty, 14 articles met all inclusion criteria for this study. The incidence of anterior knee pain was greater in knees with nonresurfaced patellas. Secondary resurfacings for anterior knee pain was needed in 8.7% of nonresurfaced knees. No difference in reported complications existed. Total knee arthroplasty resulted in improvement of functional outcome regardless of whether the patella was resurfaced. Based on the results of this meta-analysis, nonresurfacing of the patella during primary total knee arthroplasty is likely to result in a greater incidence of anterior knee pain, the need for secondary resurfacing in almost one in 10 patients, and possibly less patient satisfaction. LEVEL OF EVIDENCE: Therapeutic study, Level IV (case series). See the Guidelines for Authors for a complete description of levels of evidence.

Aged↗