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Biomedical subjects

Robert B Bourne

Publications and source records attributed to Robert B Bourne.

At least 19 recordsLinked to original sources
PubMed2006

Cost effectiveness of revision total knee arthroplasty.

UNLABELLED: Total knee arthroplasty now exceeds total hip arthroplasty as the most commonly performed joint replacement. Projections suggest the need for revision knee arthroplasty in the future will produce an immense economic burden. The excellent cost effectiveness of primary knee arthroplasty has been well established. This article explores the cost effectiveness of revision knee arthroplasty, and makes a comparison of costs between different international health care systems. While revision knee arthroplasty is more costly, technically difficult, and complicated than primary knee arthroplasty, it is still a cost effective means of improving function, pain relief, and quality of life. The role of national arthroplasty registries will be important in guiding decision making toward reducing the requirements for revision surgery. LEVEL OF EVIDENCE: Prognostic study, level II-1 (prospective study). See Guidelines for Authors for complete description of levels of evidence.

Arthroplasty, Replacement, Knee↗
PubMed2006

Preoperative evaluations in revision total knee arthroplasty.

UNLABELLED: There are many causes of total knee arthroplasty failure, and an accurate preoperative diagnosis is essential to optimize the results of revision surgery. We discuss our standard pre-operative evaluation routine and we retrospectively reviewed the last 295 patients who underwent revision total knee arthroplasty to establish the clinical value of the most commonly performed investigations used to diagnose sepsis. Routinely performed preoperative investigations include erythrocyte sedimentation rate, C-reactive protein, microbiology, bacteriology cultures of preoperative knee aspirations, and intraoperative tissue bacteriology cultures. Each investigation was compared with the reason for revision (eg, septic or aseptic) to establish the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of each. 79 cases (26.8%) were revised for infection. Of the investigations, the ESR had a sensitivity of 0.63, a specificity of 0.55, a positive predictive value of 0.39, a negative predictive value of 0.77, and an accuracy of 0.57. The respective values for C-reactive protein were 0.6, 0.63, 0.45, 0.76, and 0.62, and 0.53, 0.94, 0.75, 0.85, and 0.83 for intraoperative tissue culture. There was no preoperative investigation accurate enough to be solely relied on for diagnosing infection. We believe that clinical findings and the routine use of simple tests such as C-reactive protein, ESR, and knee aspiration yield predictable results. LEVEL OF EVIDENCE: Prognostic study, level II-1 (retrospective study). See the Guidelines for Authors for a complete description of levels of evidence.

Arthroplasty, Replacement, Knee↗
PubMed2006

Efficacy of periarticular multimodal drug injection in total knee arthroplasty. A randomized trial.

BACKGROUND: Postoperative analgesia with the use of parenteral opioids or epidural analgesia can be associated with troublesome side effects. Good perioperative analgesia facilitates rehabilitation, improves patient satisfaction, and may reduce the hospital stay. We investigated the analgesic effect of locally injected drugs around a total knee prosthesis. METHODS: Sixty-four patients undergoing total knee arthroplasty were randomized either to receive a periarticular intraoperative injection containing ropivacaine, ketorolac, epimorphine, and epinephrine or to receive no injection. The perioperative analgesic regimen was standardized. All patients in both groups received patient-controlled analgesia for twenty-four hours after the surgery, and this was followed by standard analgesia. Visual analog scores for pain, during activity and at rest, and for patient satisfaction were recorded preoperatively and postoperatively and at the six-week follow-up examination. The consumption of patient-controlled analgesia at specific postoperative time-points and the overall analgesic requirement were measured. RESULTS: The patients who had received the injection used significantly less patient-controlled analgesia at six hours, at twelve hours, and over the first twenty-four hours after the surgery. In addition, they had higher visual analog scores for patient satisfaction and lower visual analog scores for pain during activity in the post-anesthetic-care unit and four hours after the operation. No cardiac or central nervous system toxicity was observed. CONCLUSIONS: Intraoperative periarticular injection with multimodal drugs can significantly reduce the requirements for patient-controlled analgesia and improve patient satisfaction, with no apparent risks, following total knee arthroplasty.

Aged↗
PubMed2005

Factors influencing range of motion after contemporary total knee arthroplasty.

A detailed analysis of 219 total knee arthroplasties performed with a single implant design was performed. Factors significantly affecting the postoperative range of motion of total knee arthroplasties 2 years after surgery included preoperative diagnosis and preoperative range of motion. Sex, age, body mass index, femoral component size, posterior cruciate ligament status, or fixed vs mobile bearing design did not correlate with knee range of motion 2 years postoperatively.

Adult↗
PubMed2005

Computed tomographic analysis of bone support for three acetabular cup designs.

The initial stability and long-term survivorship of cementless acetabular components is partially dependent on bone-prosthesis contact patterns. This study addresses the question: What are the differences in contact patterns for hemispheric, dual geometry, and spiked designs? Quantitative and qualitative assessment of contact patterns was achieved using a novel, nondestructive computed tomography-based analysis. Eighteen cadaveric hemipelvis specimens were randomly assigned to receive one of three cup designs. The mean amount of cup contact was 48.6% in the hemisphere group, 31.9% in the dual geometry group, and 35.1 percent in the spiked group. The hemispheric design showed more contact and a more uniform contact pattern than the dual geometry design. The dual geometry design featured a tight fit at the rim of the implant. In the spiked group, the amount of bone-prosthesis contact was affected by the distance that the spikes advanced into the pelvic bone. This nondestructive imaging technique has potential future uses in in vitro and in vivo studies.

Acetabulum↗
PubMed2005

Arthroplasty options for the young patient: Oxinium on cross-linked polyethylene.

Our purpose was to determine whether metal femoral heads scratch with in vivo use, to characterize the scratching that occurs, and to determine whether this scratching affected polyethylene wear. Assessment of 133 consecutive retrieved femoral heads showed that metal femoral heads do scratch with in vivo use, that cobalt-chromium femoral heads are more scratch resistant than titanium alloy heads, and that scratching seems to be time dependent. Profilmetry studies showed that all roughness parameters (average roughness, maximum peak to lowest valley distance, mean peak height above the mean surface line, estimate of small peaks above the main plateau of the surface, and estimate of the depth of the valleys below the mean plateau of the surface with the exception of the symmetry of the profile about its mean line) showed increased roughness with time of use. Cobalt-chromium and Oxinium femoral heads were damaged in a dislocation model. Assessment of these femoral heads in a wear simulator revealed that against conventional polyethylene, a damaged Oxinium femoral head had no more wear than a new cobalt-chromium articulation on the same polyethylene (36.5/million cycles versus 38.4 mm/million). Against cross-linked polyethylene, a damaged Oxinium femoral head had minimal wear (1.5 mm cubed per Mc).

Adult↗
PubMed2005

Radiographic methods for the assessment of polyethylene wear after total hip arthroplasty.

All wear-measurement techniques assess femoral head penetration and therefore cannot distinguish between true polyethylene wear and bedding-in. Multiple wear measurements that are made at different time-intervals after bedding-in has occurred are required to determine the true wear rate. Computer-assisted edge-detection techniques offer improved accuracy and precision compared with manual techniques and appear to be ideally suited for the retrospective and prospective examination of large groups of patients with intermediate to long-term radiographic follow-up (more than five years). While radiostereometric analysis offers improved accuracy and precision compared with computer-assisted edge-detection techniques, widescale clinical application is limited because of its relative expense, the required expertise, and the fact that it can only be used in a prospective fashion.

Arthroplasty, Replacement, Hip↗
PubMed2005

Soft-tissue balancing of the hip: the role of femoral offset restoration.

Inadequate soft-tissue balancing is a major yet often underemphasized cause of failure for primary and revision total hip arthroplasty. Accordingly, contemporary cemented and cementless hip prostheses have been designed with consideration of this issue, and this has substantially increased the long-term survival of total hip replacements. Therefore, it is important for orthopaedic surgeons to be familiar with the rationale, biomechanical principles, and clinical implications associated with soft-tissue balancing of the hip as well as strategies to avoid inadequate soft-tissue balancing and systematic techniques to restore adequate soft-tissue tensioning during total hip arthroplasty.

Arthroplasty, Replacement, Hip↗
PubMed2004

A quantitative analysis of bone support comparing cementless tapered and distal fixation total hip replacements.

The purpose of this study was to develop a technique to accurately assess cementless femoral stem-bone contact. Using this technique, differences in contact patterns between tapered (Synergy) and cylindrical distal fixation (Prodigy) cementless stems were explored. Femurs were prepared and the 2 types of femoral stems were implanted. After implantation, the femurs were imaged in a spiral computed tomography scanner and analyzed using novel custom-developed imaging software. This analysis used a geometric deformable-model UNIX-based software that determined bone-prosthesis contact area. The tapered stem features proximal, cancellous bone contact and a 3-point fixation pattern. The cylindrical distal fixation stem demonstrates cortical support in the distal aspect of the stem.

Algorithms↗
PubMed2004

Isolated liner exchange in revision total hip arthroplasty: clinical results using the direct lateral surgical approach.

Twenty-four hips (23 patients) underwent isolated polyethylene liner exchange (modular and nonmodular liners) via the direct lateral surgical approach for a preoperative diagnosis of polyethylene wear and acetabular osteolysis. Accessible osteolytic lesions were bone grafted with cancellous allograft. Patients were followed up clinically and radiographically, with a mean follow-up time of 36 months (range, 12-100 months). A computer-assisted method measured lesional area from the radiographs of the 18 hips that presented with osteolysis. Seventeen of 18 lesions either regressed or resolved since the procedure. Two patients required repeat revisions, and no dislocations were noted. Clinically, both Harris Hip and Western Ontario and McMaster Universities Osteoarthritis Index scores improved postoperatively. In selected patients, isolated liner exchange with or without bone grafting is effective for treating polyethylene wear and associated osteolysis. Dislocation rates with revision may be reduced using a surgical approach that preserves an adequate capsular layer for closure in liner exchange surgery.

Adult↗
PubMed2004

The dislocating hip: what to do, what to do.

Dislocation complicates between 1% and 3% of primary total hip arthroplasties (THAs) and 7% to 10% of revision procedures. Sixty percent of dislocations occur within the first 5 weeks. Closed reduction is successful in 67% of cases. If the hip keeps dislocating, revision surgery for instability is successful in only about 61% of patients. Many successful techniques have been described to deal with recurrent instability, including trochanteric advancement, modular component exchange, jumbo femoral heads, a bipolar or tripolar arthroplasty, or a constrained acetabular component. This article discusses the results of various surgical interventions and presents a treatment algorithm.

Algorithms↗
PubMed2004

Zirconia femoral head fractures: a clinical and retrieval analysis.

Zirconia femoral heads provide increased fracture strength, but 343 zirconia head failures have been documented since 2000. Retrieval analysis of 6 fractured heads, 4 suspect heads, 4 control zirconia heads, and 2 failed alumina heads was performed. Zirconia failures have been isolated to heads sintered in a "tunnel" furnace introduced in 1998. The monoclinic composition at the taper surface of fractured and nonfractured heads was significantly elevated (21% to 68%) compared to that of control zirconia heads (less than 5%). Electron microscopy identified circular fracture footprints unique to the zirconia heads produced in the tunnel furnace. Cobalt chrome heads were used in the urgent revision setting due to Morse taper damage. Partial capsulectomy was performed in an effort to reduce future third body wear. Monoclinic phase transformation following implantation remains a potential mechanism of ceramic head failure. We recommend that patients with recalled zirconia heads be advised of a potential fracture risk.

Adult↗
PubMed2004

Prophylactic use of antibiotic bone cement: an emerging standard--in the affirmative.

Deep infection is a devastating complication following total joint arthroplasty. Preclinical testing; randomized; clinical trials; national joint replacement data; and our experience indicate that the use of antibiotic-impregnated bone cement is a potentially effective strategy in reducing the risk of deep infection following both primary and revision total joint arthroplasty. Allergic reactions, bacterial resistance, and cost represent barriers to the widespread use of antibiotic bone cement.

Anti-Bacterial Agents↗
PubMed2004

Radiographic changes in the patella following quadriceps turndown for revision total knee arthroplasty.

Quadriceps turndown is a technique that may be used to enhance exposure of the tight total knee arthroplasty (TKA), particularly in the revision scenario. This technique does, however, compromise the vascularity of the patella, with avascular necrosis (AVN) being a possible sequela. A modified Coonse-Adams quadriceps turndown was performed in 29 revision TKAs in 27 patients. Immediate preoperative and sequential postoperative radiographs were analyzed for changes in the patella, including sclerosis, flattening, fracture, and fragmentation, as evidence of possible AVN, and clinical scores were collected prospectively. Eight patellae had such radiographic changes. Despite a lack of corresponding worsening in clinical outcome in these patients, quadriceps turndown is shown to have a high risk of subsequent changes consistent with patellar AVN, and should be avoided when other available techniques can achieve satisfactory exposure.

Aged↗
PubMed2004

Intraoperative complications of revision hip arthroplasty using a porous-coated, distally slotted, fluted femoral stem.

Intraoperative complications of 175 cementless revision total hip arthroplasties done at four institutions using a porous-coated, uncemented, distally slotted, fluted femoral stem were reviewed. Three types of complications were recorded: eccentric reaming, femoral perforation, and femoral fracture. Intraoperative complications occurred in 16 patients (9.1%). There was no statistically significant association between complication rate and type of surgical approach, stem length, stem diameter, or host bone quality. This complication rate is comparable to or lower than that reported with the use of similar uncemented long femoral revision stems.

Adult↗
PubMed2004

The consequences of not resurfacing the patella.

The decision of whether to resurface the patella during total knee arthroplasty remains controversial. In this study, a meta-analysis of national joint replacement registry data, bilateral total knee replacement studies, selective resurfacing reports, and randomized clinical trials was done Although the evidence seems to support patellar resurfacing, this issue remains inconclusive because of problems generalizing from one implant to another and the short-term nature of available studies. Based on existing data, patellar resurfacing seems reasonable in most total knee replacements. Not resurfacing the patella might be considered in selected younger patients (<60 years) with mild or no patellar arthritis, a well-tracking extensor mechanism, and particularly if a patella-friendly femoral component is used.

Arthroplasty, Replacement, Knee↗