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Biomedical subjects

John J Callaghan

Publications and source records attributed to John J Callaghan.

At least 19 recordsLinked to original sources
PubMed2004

Cementless acetabular fixation at fifteen years. A comparison with the same surgeon's results following acetabular fixation with cement.

BACKGROUND: Loosening of the acetabular component is the major long-term problem associated with total hip arthroplasty with cement. The purpose of the present study was to evaluate the minimum thirteen-year results associated with cementless acetabular components that had been inserted by a single surgeon and to compare them with the results associated with cemented acetabular components that had been inserted by the same surgeon. METHODS: One hundred and twenty consecutive, nonselected primary total hip replacements were performed in 108 patients with use of a Harris-Galante-I cementless acetabular component and a cemented femoral component with a 28-mm head. The patients were evaluated clinically with use of a standard terminology questionnaire, and they were evaluated radiographically for loosening, component migration, wear, and osteolysis. The rates of revision for aseptic loosening and radiographic evidence of loosening for this cohort were compared with the rates for four previously reviewed consecutive series of hips in which the acetabular component had been inserted with cement. All patients were managed by the same surgeon, were followed for thirteen to fifteen years, and were evaluated with use of the same two criteria (revision and loosening) as the end points for Kaplan-Meier analysis. RESULTS: Sixty-six patients (seventy-two hips) were living and forty-two patients (forty-eight hips) had died after thirteen to fifteen years of follow-up. No acetabular component had been revised because of aseptic loosening, and no acetabular component had migrated. With revision of the acetabular component for any reason as the end point, the survival rate was 81% +/- 8% at fifteen years. With revision of the acetabular component for clinical failure (osteolysis, wear, loosening, or dislocation) as the end point, the survival rate was 94% +/- 8% at fifteen years. Among the seventy hips with at least thirteen years of radiographic follow-up, five had pelvic osteolysis and three had had revision of a well-fixed acetabular component because of pelvic osteolysis secondary to polyethylene wear. The mean linear wear rate was 0.15 mm/yr (0.12 mm/yr when one outlier was excluded). CONCLUSIONS: In terms of fixation, Harris-Galante-I cementless acetabular components performed better than did cemented 22-mm-inner-diameter Charnley acetabular components as well as 28-mm-inner-diameter all-polyethylene and metal-backed acetabular components that had been inserted by the same surgeon. However, the rate of wear was greater in association with the Harris-Galante-I cementless components than it was in association with the Charnley cemented all-polyethylene components.

Acetabulum↗
PubMed2003

Kinematics, kinetics, and finite element analysis of commonplace maneuvers at risk for total hip dislocation.

Dislocation remains a disturbingly frequent complication of total hip arthroplasty (THA). Over the past several years, increasingly rigorous biomechanical approaches have been developed for studying dislocation, both experimentally and computationally. Realism of the input motion challenge data has lagged behind most other aspects of this body of work, and anterior dislocation maneuvers remain unstudied. To enhance realism of biomechanical studies of dislocation, motion data are here reported for ten THA-aged subjects, each repeatedly performing seven maneuvers known to be dislocation-prone. An optoelectronic motion tracking system and a recessed force plate captured the kinematics and ground reaction forces of these maneuvers. Using an established inverse dynamics model to estimate hip joint loading, 354 motion trials were evaluated using an existing finite element model of THA dislocation. Worst-case-scenario THA constructs were simulated (22 mm femoral head, acetabular cup orientations at the limit of the accepted safe zone), in order to deliberately induce impingement and dislocation. The results showed a high incidence of computationally predicted dislocation for all movements studied, but also that risk was very maneuver-dependent, with patients being six times more likely to dislocate from a low-sit-to-stand maneuver than from stooping. These new motion data hopefully will help facilitate systematic efforts to reduce the incidence of dislocation.

Activities of Daily Living↗
PubMed2003

Use of constrained acetabular components for hip instability: an average 10-year follow-up study.

The short-term efficacy of using constrained acetabular components for hip instability in the total hip arthroplasty construct has been documented. However, long-term concerns including late dislocation, loosening of components, and osteolysis have not been addressed. The authors evaluated, at an average 10.3-year follow-up, 101 tripolar constrained components (Stryker Howmedica Osteonics) used in the total hip arthroplasty construct. At final follow-up, 6 hips had dislocated or had failure of the constrained component, 5 of which were revised. In addition, 4 hips were revised for aseptic loosening of the acetabular component, 4 hips were revised for aseptic femoral loosening, and 1 hip was revised for acetabular osteolysis. Considering the complexity of the cases, this component has provided durable fixation and hip stability at this intermediate-term follow-up.

Acetabulum↗
PubMed2003

A prospective randomized trial of cemented femoral components with polished versus grit-blasted surface finish and identical stem geometry.

This randomized, prospective study compared 2 cemented hip stems that differed only in the surface finish, which was polished or grit blasted. A total of 226 hybrid total hips were evaluated at an average of 4.8 years postoperatively. No stem in either group was loose or revised for aseptic loosening. There was one case of significant distal lysis in the grit-blasted group. There was no statistical difference between polished and grit-blasted stems in incidence of lysis or bone-cement radiolucency. Harris Hip score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and SF-36 analysis showed no difference between groups. In conclusion, when adequate cement mantles are achieved around the femoral component, little difference in construct durability between polished and grit-blasted surface finish components can be detected at 4.8-year follow-up for this stem design.

Adult↗
PubMed2003

Orthopaedic crossfire--Larger femoral heads: a triumph of hope over reason! In the affirmative.

The authors' wear studies of total hip arthroplasty cohorts have shown that less polyethylene wear and less deleterious effects of third body debris were found when smaller femoral head sizes were used. The authors' sliding-distance-coupled finite element model findings were corroborated by these clinical wear studies. Thus, with polyethylene on metal bearing surfaces, less wear should occur when smaller head sizes are used. Careful, precise component positioning is important to prevent dislocation.

Finite Element Analysis↗
PubMed2003

Gait cycle finite element comparison of rotating-platform total knee designs.

Functional load transmission and kinematic performance were compared for standard versus posterior-stabilized versions of a rotating-platform total knee implant, over a standardized loading cycle, using three-dimensional contact finite element analysis. These two design variants differ primarily in terms of the latter's polyethylene insert having a cam that engages with the femoral component during appreciable flexion, thereby inducing femoral component rollback. The finite element model, previously validated experimentally, afforded direct comparisons of anterior lift-off of the insert from the tibial tray, of bearing mobility (insert rotation about the pivot post), of femoral rollback, and of metal-on-polyethylene contact stresses at the bearing and backside surfaces of the insert. Both design variants generally performed comparably, exhibiting an internal and external rotation range of approximately 5 degrees, approximately 1.5 mm peak lift-off at the anterior aspect of the insert, and approximately 15 mm of posterior rollback, the respective maxima for both designs occurring at approximately the same instants in the gait cycle. However, the posterior-stabilized design had slightly more rollback, and slightly less anterior lift-off and rotation, than did the standard rotating-platform design. Peak polyethylene stresses occurred on the backside of the insert near the posterior edge of the medial compartment, the magnitude being approximately 18% higher for the posterior-stabilized design (21 MPa) than for the standard design.

Finite Element Analysis↗
PubMed2003

Functional outcome after revision hip arthroplasty: a metaanalysis.

The current study systematically reviews the literature describing patient outcomes after revision total hip arthroplasties using conventional global hip score ratings. Two thousand one hundred thirty-seven English-language articles published from 1966 through 2000 were identified through a computerized literature search and bibliography review. A three-step filter process was used to identify articles to be included in the metaanalysis. Forty-two articles with 2578 patients had data abstracted for the analysis. Metaanalysis of global hip scores was done using a fixed effects model with the assumption that the variances of each measurement were identical across studies. Thirty-nine articles reporting on 46 cohorts progressed through three filters and went to data extraction and analysis. Revision total hip arthroplasty is a reasonably safe and effective procedure for failed hip replacement Based on this exploratory analysis revision hip procedures seem to have comparable longevity, to primary hip replacement but appear to have slightly lower functional outcome (as measured by global hip scores), and slightly higher morbidity and mortality rates than primary procedures. Inconsistent reporting in the original studies limited exploration of other factors that may have affected outcomes.

Arthroplasty, Replacement, Hip↗
PubMed2003

Long-term function after Charnley total hip arthroplasty.

The purpose of this study was to report the functional results and mortality rates of a consecutive series of patients younger than 50 years after Charnley total hip arthroplasty. The original group of 69 patients (93 hips) was followed up until death or a minimum of 25 years after surgery. Of the original 93 hips, 29 had been revised at some point. Functional outcomes included the Short Form-36, Western Ontario and McMaster University University Osteoarthritis Index (WOMAC), 6-minute walk distance, Noyes activity scale, and Harris hip scores and included followup in 42 of 43 living patients. The functional outcome of patients was good, with comparable Short Form-36 scores compared with normative values of healthy age-matched subjects. The 6-minute walk distances and WOMAC scores were slightly lower than healthy normatives but were thought to be influenced by medical comorbidities. Although comorbid medical and musculoskeletal conditions significantly hindered most measures of function, revision surgery or radiographic loosening of components had no significant influence on function. The mortality rates of this cohort of patients were similar to normative values at both 10 and 25 years after surgery.

Adult↗
PubMed2003

Twenty-five-year results after Charnley total hip arthroplasty in patients less than fifty years old: a concise follow-up of a previous report.

We report the updated results for a previously evaluated cohort of patients who were less than fifty years old when they underwent Charnley total hip arthroplasty with cement. The original cohort consisted of ninety-three total hip arthroplasties performed in sixty-nine patients. The patients were followed for a minimum of twenty-five years after surgery or until death. The present report describes the findings of the radiographic and functional follow-up, which was performed for forty-two of the forty-three living patients. At the time of the latest follow-up, twenty-nine (31%) of the ninety-three total hip replacements had been revised or removed. Eighteen acetabular and five femoral components were revised secondary to aseptic loosening. The combined prevalence of radiographic failure or revision because of aseptic loosening was 13% for the femoral components and 34% for the acetabular components. Comorbid medical conditions significantly hindered results on each functional subscale (p < 0.05). This study demonstrates the durability of cemented total hip replacements in a young patient population. Sixty-nine percent of the original hip replacements were functioning well at the latest follow-up examination or at the time of death, and only 5% required more than one revision arthroplasty.

Adolescent↗
PubMed2003

Results of porous-coated anatomic total hip arthroplasty without cement at fifteen years: a concise follow-up of a previous report.

The purpose of this study was to update the results of a prospective series of primary cementless total hip arthroplasties after a minimum of fifteen years of follow-up. It is one of the first studies of cementless total hip arthroplasties followed for a minimum of fifteen years. One hundred consecutive Porous Coated Anatomic (PCA) total hip replacements were implanted between October 1983 and January 1986. Fifty-five patients (sixty-four hips) that were alive at a minimum of fifteen years postoperatively are the focus of the present study. At this time of follow-up, at an average of 15.6 years (range, fifteen to seventeen years) after the total hip arthroplasty, 17% (seventeen hips) of the entire cohort and 23% (fifteen hips) of the living cohort had undergone revision because of loosening of the acetabular component or osteolysis. Seven percent (seven hips) of the entire cohort and 6% (four hips) of the living cohort had undergone revision for loosening of the femoral component or osteolysis. Only four femoral stems had been revised for isolated loosening (without osteolysis). The PCA femoral component proved to be durable at a minimum of fifteen years postoperatively, while the acetabular component was less durable.

Adult↗
PubMed2003

A biomechanical analysis of polyethylene liner cementation into a fixed metal acetabular shell.

BACKGROUND: A common clinical scenario encountered by an orthopaedic surgeon is a patient with a secure cementless acetabular shell and a failed polyethylene liner. One treatment option is to cement a new liner into the fixed shell. The purpose of this study was to evaluate technical variables to improve the mechanical strength of such cemented liner constructs. METHODS: The contributions of shell texturing, liner texturing, and cement mantle thickness (between the liner and the shell) were evaluated by comparing torsional strength (among nine groups of constructs) and lever-out strength (among eight groups of constructs). RESULTS: Failure almost always occurred at the cement-liner interface. The two exceptions (failure at the shell-cement interface) occurred with a polished, untextured shell with no screw-holes. This finding indicates that if a shell has existing texturing (such as holes), further intraoperative scoring of the shell is unnecessary, but some sort of texturing is necessary to avoid construct failure at the shell-cement interface. Textured liners had significantly (a = 0.05) greater torsional and lever-out strength than untextured liners. The greatest construct strength occurred when liner grooves were oriented so as to oppose the applied loading. A 4-mm-thick cement mantle resulted in slightly greater torsional strength than a 2-mm-thick cement mantle, and a 2-mm-thick cement mantle resulted in considerably greater lever-out strength than a 4-mm-thick cement mantle, but these differences were not significant. CONCLUSIONS: When cementing a liner into a well-fixed shell, a surgeon should ensure that both the shell and the liner are textured, as interdigitation of the cement with the shell and the liner is crucial to the mechanical strength of this construct.

Arthroplasty, Replacement, Hip↗
PubMed2003

Osteonecrosis of the hip: management in the 21st century.

Osteonecrosis of the femoral head is a progressive condition that often leads to collapse of the femoral head. The ultimate goal in the treatment for osteonecrosis of the hip is preservation of the femoral head. However, the condition is difficult to treat because it is associated with a number of different diseases, and the etiology and natural history of the condition have not been definitively determined. The delineation of new information regarding the etiology, pathogenesis, and natural history of osteonecrosis is ongoing. Core decompression, vascularized and nonvascularized bone grafting procedures, and arthroplasty procedures play an important role in treatment.

Algorithms↗
PubMed2003

Clinical biomechanics of wear in total hip arthroplasty.

Complementary clinical and laboratory studies were performed to identify variables associated with polyethylene wear following total hip replacement, and to elucidate the mechanisms responsible for accelerated wear in the total hip arthroplasty construct. Observational cohort studies were performed using a prospective clinical database of more than 4000 consecutive primary total hip arthroplasties performed by a single surgeon, to identify wear-related variables. These variables included head size, acetabular/femoral component impingement, and third body debris. Novel digital edge detection techniques were developed and employed to accurately measure wear, and to determine the relationships of head size and third body debris to acceleration of wear. A novel sliding-distance-coupled finite element model was formulated and employed to examine the mechanisms responsible for wear. The long-term cohort studies demonstrated smaller head sizes to be associated with less wear. Third body debris generated from cable fretting was associated with an increase in wear, osteolysis, and acetabular loosening, especially with larger head sizes. The sliding-distance-coupled finite element model replicated the wear rates occurring in vitro and in vivo, demonstrating the importance of sliding distance on polyethylene wear following total hip arthroplasty. It also demonstrated substantial increases in wear associated with femoral head scratching from third body debris. Further extension of the finite element formulation demonstrated the potential for acetabular component rim damage from impingement wear, and the enhanced potential for third body ingress to the bearing surface with larger head sizes. Edge detection wear measurement techniques demonstrated that early wear rates were predictive of long-term wear rates. These complementary clinical and laboratory investigations have provided insight into 1) the significance of sliding distance and physiologic loci of motion as contributing factors in minimizing wear, 2) the deleterious effects of third body particulates in accelerating wear, 3) the potential for, and factors related to, impingement wear, and 4) the potential advantages and compromises related to the use of larger head sizes in the bearing surface construct.

Arthroplasty, Replacement, Hip↗
PubMed2003

Early postoperative mortality following total hip arthroplasty in a community setting: a single surgeon experience.

The senior author performed 4967 total hip arthroplasties, 4164 primary and 803 revision, between 1970 and 1996 in a community setting. All charts were evaluated for postoperative death including in-house, 30, 60, and 90 days following the procedure. 1.0 per cent of patients (42) died following a primary procedure and 0.87 per cent (7) died following a revision procedure within 3 months of surgery. The number of in-house deaths were 26 (0.52 per cent), including 21 in the primary group (0.5 per cent) and 5 in the revision group (0.62 per cent). In both the primary and revision situation and independent of co-morbidities, age greater than 70 years was significantly associated with increased risk for post-operative mortality (p<0.0001), with 0.44% mortality in patients aged 70 years or younger (0.51 per cent primary and 0.00 per cent revision), and 1.45 per cent mortality in patients greater than 70 years of age (1.38 per cent primary and 1.86 per cent revision). This experience of a single surgeon with a high volume community practice performing both primary and revision total hip arthroplasty, documents a low but significant incidence of postoperative death in the first 3 months following total hip arthroplasty (0.98 per cent).

Aged↗
PubMed2002

Effects of acetabular component orientation on dislocation propensity for small-head-size total hip arthroplasty.

OBJECTIVE: Examine the role of surgical orientation of the acetabular cup on posterior dislocation propensity for small-head-size total hip arthroplasty. DESIGN: A finite element model of a widely used total hip arthroplasty system was examined for peak resisting moment and range-of-motion prior to impingement, as well as prior to onset of posterior dislocation. Acetabular component surgical orientation was varied. BACKGROUND: Dislocation is a leading cause of total hip replacement failure, with an incidence between 2% and 11%. Clinical registries imply acetabular component orientation to be a leading predictor of dislocation. The finite element method permits this complex kinetic behavior to be addressed systematically. METHODS: Twenty-five combinations of cup abduction (five angles) and anteversion (five angles) were studied, with the resultant resisting moment about the cup center being tracked in each case. Key events were benchmarked, and a novel dislocation resistance index was developed for multi-factor comparison. RESULTS: Increasing tilt and/or anteversion resulted in a monotonically increasing range-of-motion prior to impingement, as well as increased peak resisting moment. Range of motion was more sensitive to tilt, while peak resisting moment was more sensitive to anteversion. Peak resisting moment for 22-mm head size was nearly 25% less than that for a 26-mm head. CONCLUSIONS: Increased cup tilt and anteversion discourage posterior dislocations of small-head-size components. RELEVANCE: Pre-existing soft tissue compromise and untoward patient motions/postures are largely beyond surgeon control. However, other factors being equal, especially for small-head-size components, many posterior dislocations that would otherwise occur might be prevented by suitable tilt and anteversion of the acetabular component.

Acetabulum↗