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Biomedical subjects

J J Callaghan

Publications and source records attributed to J J Callaghan.

At least 19 recordsLinked to original sources
PubMed1997

Long-term results of revision total hip arthroplasty with improved cementing technique.

We performed 83 consecutive cemented revision total hip arthroplasties in 77 patients between 1977 and 1983 using improved cementing techniques. One patient (two hips) was lost to follow-up. The remaining 76 patients (81 hips) had an average age at revision of 63.7 years (23 to 89). At the final follow-up 18 hips (22%) had had a reoperation, two (2.5%) for sepsis, three (4%) for dislocation and 13 (16%) for aseptic loosening. The incidence of rerevision for aseptic femoral loosening was 5.4% and for aseptic acetabular loosening 16%. These results confirm that cemented femoral revision is a durable option in revision hip surgery when improved cementing techniques are used, but that cemented acetabular revision is unsatisfactory.

Acetabulum↗
PubMed1997

Digital edge-detection measurement of polyethylene wear after total hip arthroplasty.

A novel digital edge-detection computer technique was developed to measure polyethylene wear after total hip arthroplasty. The new method objectively infers the margins of the component by evaluating gradients of gray-scale intensity on digitized images of the radiographs. Compared with previous methods for measurement of wear, digital edge detection substantially reduces observer subjectivity. The technique was validated directly by measuring wear artificially produced by spherical-front milling of polyethylene liners in a benchtop series. Under such conditions, digital edge detection proved 6.4 times more accurate and 7.1 times more reproducible than manual measurement with conventional circular templates. In addition, clinical application of the new digital imaging technique was illustrated in a series of forty-three patients in whom a metal-backed acetabular cup had been inserted with cement. A random-coefficients prediction algorithm was invoked to estimate long-term wear (mean late rate of wear for the cohort, 0.087 millimeter per year at a mean of 118 months after the operation) on the basis of measurements of short-term wear (mean early rate of wear for the cohort, 0.154 millimeter per year at a mean of twenty-four months).

Algorithms↗
PubMed1997

Charnley total hip arthroplasty with use of improved techniques of cementing. The results after a minimum of fifteen years of follow-up.

Three hundred and fifty-seven consecutive Charnley total hip arthroplasties were performed in 320 patients with use of a so-called second-generation technique of cementing between July 1976 and June 1978. This technique includes use of a distal femoral intramedullary cement plug, hand-mixing of the cement, and use of a cement gun to deliver the cement into the femoral canal in a retrograde fashion. At the time of the latest follow-up evaluation, a minimum of fifteen years after the arthroplasty, 130 patients (142 hips) were still alive, 189 patients (214 hips) had died, and one patient (one hip) had been lost to follow-up. A radiograph was made for 116 (82 per cent) of the 142 hips in the 130 surviving patients. Of the 356 hips that had not been lost to follow-up, thirty-three (9 per cent) had had a revision and two (1 per cent), a Girdlestone resection arthroplasty during the follow-up period. Nineteen hips (5 per cent) were revised because of aseptic loosening of the femoral or acetabular component, or both (two hips); seven (2 per cent), because of loosening with infection; and seven (2 per cent), because of dislocation. The two resection arthroplasties were performed because of loosening with infection; both were done in patients who died before the time of the latest follow-up evaluation. Of the 142 hips in the 130 patients who were alive at a minimum of fifteen years, twenty-two (15 per cent) had been revised: fifteen (11 per cent), because of aseptic loosening; three (2 per cent), because of loosening with infection; and four (3 per cent), because of dislocation. Revision of the femoral component because of aseptic loosening (excluding components that were revised because of dislocation or infection) was performed in four (1 per cent) of the entire series of 356 hips and in three (2 per cent) of the 142 hips in the 130 patients who survived for at least fifteen years. Two of the 356 hips and two of the 142 hips had aseptic loosening of the acetabular as well as the femoral component at the time of the revision. Loosening of the femoral component, defined as aseptic loosening leading to revision or as definite or probable radiographic loosening, occurred in ten (3 per cent) of the 356 hips and in six (5 per cent) of the 116 hips for which radiographs were made at a minimum of fifteen years. The acetabular component was revised because of aseptic loosening in seventeen (5 per cent) of the entire series of 356 hips and in fourteen (10 per cent) of the 142 hips in the 130 patients who survived for at least fifteen years. The acetabular component loosened without infection in forty-one (12 per cent) of the 356 hips and in twenty-six (22 per cent) of the 116 hips for which radiographs were made at a minimum of fifteen years. In two of these patients, the femoral component was also revised. Thus, of the entire series of 356 hips, two had a revision of the femoral component alone because of aseptic loosening; fifteen, a revision of the acetabular component alone; and two, a revision of both components. Of the 142 hips in the 130 patients who survived for at least fifteen years, one was revised for loosening of the femoral component alone; twelve, for loosening of the acetabular component alone; and two, for loosening of both components. These findings demonstrate long-term durability of fixation of the femoral component but less reliable fixation of the acetabular component, even when the surgeon is experienced and improved techniques of cementing are used.

Activities of Daily Living↗
PubMed1997

The Frank Stinchfield Award. Contribution of cable debris generation to accelerated polyethylene wear.

The decision of the senior author of a large total hip replacement practice to switch from wire to braided cable for reattachment of the greater trochanter provided the opportunity to evaluate the long term effects (on acetabular component wear, osteolysis, and component loosening) caused by the introduction of metallic debris (generated by cable fretting and breakage) into the total hip arthroplasty construct. Seven hundred and nine consecutive primary total hip arthroplasties were performed during a 5-year period and followed up for a minimum of 10 years. Wire and cable reattachment of the greater trochanter was used sequentially. At minimum 10-year followup the cable group had significantly more wear, osteolysis, and acetabular radiographic evidence of loosening. Those involved in the design and use of total hip arthroplasty devices must minimize potential sources of metallic debris and other potential sources for third body wear in the total hip arthroplasty construct to help ensure longevity of the arthroplasty.

Adolescent↗
PubMed1997

Finite element analysis of acetabular wear. Validation, and backing and fixation effects.

A two-phase investigation was undertaken to study computational performance aspects of a recently developed finite element formulation that has shown promise in the study of design related influences on total hip arthroplasty wear. In the first phase, computational model predictions were evaluated against directly corresponding physical wear measurements performed in a biaxial rocking hip simulator. The discrepancy between the predictions and the measurements was approximately 4.1%. In the second phase, a bony support bed was introduced to supersede the model's previous simplifying assumption of rigid support at the cup backing. Other factors being equal, computed wear rates differed negligibly for three very different cup backing and fixation modalities studied with the new bony bed support condition, and for two individual cups studied with bony bed support versus the rigid backing support simplification.

Acetabulum↗
PubMed1997

Total hip arthroplasty in the young adult.

The durability of cemented and hybrid total hip arthroplasty in the young adult was evaluated. A consecutive series of primary cemented total hip arthroplasties performed between 1970 and 1976, and a consecutive series of primary hybrid total hip arthroplasties performed between 1986 and 1991, were evaluated for revision and radiographic loosening of the components. All patients were younger than 50 years of age at the time of surgery and all surgery was performed by one surgeon. At minimum 20 years followup of the cemented group (93 hips in 69 patients) 22% of hips (21 hips) were revised for aseptic loosening (5% of femoral components, five hips, and 19% of acetabular components, 18 hips). At 5- to 10-year followup of the hybrid group (45 hips in 37 patients) 18% of hips (eight hips) were revised for aseptic loosening (18% of femoral components, eight hips, and 0% of acetabular components, 0 hips). Although the cemented femoral component used in the hybrid series showed a marked increase in revision and loosening compared with the cemented series, the excellent fixation obtained with uncemented acetabular components has encouraged the authors to continue the use of hybrid fixation in the young adult. However, the femoral component has been modified to incorporate a polished surface finish and a stem geometry similar to the Charnley flat back prosthesis used in the cemented series.

Adult↗
PubMed1996

Adaptive finite element modeling of long-term polyethylene wear in total hip arthroplasty.

Adaptive remeshing capability was added to an existing sliding-distance-coupled finite element model of polyethylene wear in total hip arthroplasty. This augmentation allowed earlier postoperative wear simulation to be extended to the clinically more significant long-term regimen (as long as 20 years). Loads and femoral head excursions were taken from a physically validated gait analysis model of a patient with an instrumented total hip replacement. For otherwise identical 22, 28, and 32 mm components, the least volumetric wear but the most linear wear occurred for the 22 mm head. When the polyethylene thickness in a 22 mm component was reduced to the same as that in a 32 mm component, the volumetric wear rate for the 22 mm component was still much less than that for the larger component, indicating that sliding distance (head size), rather than polyethylene liner thickness, was primarily responsible for the difference in rates. A "28 mm" series, for which head sizes were varied across the range of currently accepted industrial tolerances, showed that although initial wear rates were greatest for the least congruent articulations, the long-term volumetric wear was nearly the same, regardless of initial clearance.

Arthroplasty↗
PubMed1996

Imaging of muscle injuries.

Although skeletal muscle is the single largest tissue in the body, there is little written about it in the radiologic literature. Indirect muscle injuries, also called strains or tears, are common in athletics, and knowing the morphology and physiology of the muscle-tendon unit is the key to the understanding of these injuries. Eccentric muscle activation produces more tension within the muscle than when it is activated concentrically, making it more susceptible to tearing. Injuries involving the muscle belly tend to occur near the myotendinous junction. In adolescents, the weakest link in the muscle-tendon-bone complex is the apophysis. Traditionally, plain radiography has been the main diagnostic modality for evaluation of these injuries; however, with the advent of MRI it has become much easier to diagnose injuries primarily affecting the soft tissues. This article reviews the anatomy and physiology of the muscle-tendon unit as they relate to indirect muscle injuries. Examples of common muscle injuries are illustrated.

Adolescent↗
PubMed1996

A sliding-distance-coupled finite element formulation for polyethylene wear in total hip arthroplasty.

A three-dimensional, nonlinear contact finite element (FE) model of total hip replacement, linked to a sliding-distance-coupled wear algorithm, was used to study polyethylene wear rates for three different femoral head sizes. Hip resultant loads from a validated gait analysis model were used in the FE model to determine contact stress distributions on the polyethylene bearing surface, for 16 discrete instants of stance phase. Sliding distances of points on the femoral head surface were obtained from the corresponding flexion/extension kinematics. Wear rates were determined by a custom-written computer program that used a relationship that coupled contact stress, sliding distance, and a pin-on-disk determined wear coefficient. The wear rates computed by this formulation were well within clinically observed ranges for each component size.

Algorithms↗
PubMed1996

Revision total hip arthroplasty with cement after cup arthroplasty. Long-term follow-up.

Ninety-six cup arthroplasties (eighty-three patients) were converted to total hip arthroplasties with cement between July 1970 and August 1982. Fifty-eight hips (fifty patients) were followed for at least ten years, or to failure after a shorter interval, and eight other hips (eight patients) had a subsequent operation because of a deep infection. Of the fifty-eight hips that were followed for at least ten years or to failure, nine (16 per cent) were revised because of aseptic loosening of the acetabular component, one (2 per cent) was revised because of a traumatic fracture of the femur, and none were revised because of loosening of the femoral component. Kaplan-Meier survivorship analysis with revision for any reason (including infection) as the end point showed a rate of survival of 92 +/- 6 per cent (average and 95 per cent confidence interval) at ten years and of 74 +/- 12 per cent at twenty years. When the hips in which an infection had occurred were excluded, and with revision because of aseptic loosening of the acetabular component as the end point, the rate of survival was 84 +/- 10 per cent at twenty years; no acetabular component was revised because of aseptic loosening in the first ten years. When the hips in which an infection had occurred were excluded, and with radiographic evidence of definite or probable loosening of the acetabular component, or aseptic loosening of the acetabular component necessitating revision, as the end point, the rate of survival was 91 +/- 6 per cent at ten years and 53 +/- 22 per cent at twenty years. The present study demonstrates the durability of total hip replacement with cement after the failure of a cup arthroplasty and further substantiates the excellent long-term clinical and radiographic results that can be obtained with insertion of a femoral component with cement.

Adolescent↗
PubMed1996

Revision of a failed cemented total hip prosthesis with insertion of an acetabular component without cement and a femoral component with cement. A five to eight-year follow-up study.

Sixty-one consecutive so-called hybrid revision total hip arthroplasties were performed in fifty-five patients by one surgeon, from 1986 through 1988, for mechanical failure of a cemented total hip prosthesis. In all of the patients, the acetabular and femoral components were revised to a porous-coated Harris-Galante acetabular component inserted without cement and an Iowa femoral component inserted with cement. Contemporary cementing techniques were used, but structural bone graft was not. The over-all prevalence of repeat revision for aseptic loosening was 0 per cent for the acetabular components and 3 per cent (two hips) for the femoral components. In addition, 2 per cent (one) of the acetabular components and 5 per cent (three) of the femoral components demonstrated radiographic evidence of loosening. In the forty-three patients (forty-nine hips) who were alive at an average of seventy-four months (range, sixty to ninety-five months) after the revision, none of the acetabular components and 2 per cent (one) of the femoral components were revised again for aseptic loosening. An additional 2 per cent (one) of the acetabular components and 6 per cent (three) of the femoral components were radiographically loose. Ninety-eight per cent (forty-one) of the forty-two living patients (98 per cent [forty-seven] of the forty-eight hips) who had a clinical examination at least five years after the revision had increased function; 90 per cent (thirty-eight) of these patients (forty-four [92 per cent] of the hips) were satisfied with the result. The group that had a hybrid revision was compared with a group of seventy patients (seventy-four hips) who had had a revision total hip arthroplasty with use of contemporary cementing techniques for both components. These revisions had been performed by the same surgeon, before he performed the hybrid revisions, and the prevalence of repeat revision of the acetabular component was 7 per cent (five hips) and that of the femoral component was 4 per cent (three hips). In addition, 16 per cent (twelve) of the acetabular components and 3 per cent (two) of the femoral components were radiographically loose. The comparison group was not a consecutive series, as only the patients who had had radiographs made five to eight years after the revision were evaluated. In the fifty-two such patients (fifty-six hips) who were alive at five years after the revision with cement (average duration of radiographic follow-up, seventy-seven months; range, sixty to ninety-nine months), 9 per cent (five) of the acetabular components and 5 per cent (three) of the femoral components were revised again for aseptic loosening. An additional 21 per cent (twelve) of the acetabular components and 4 per cent (two) of the femoral components were radiographically loose. The results of the present study demonstrated a significant improvement (p = 0.0001) in the survival of the acetabular component of so-called hybrid revision total hip arthroplasties compared with that of revision total hip arthroplasties with cement performed by the same surgeon and followed for a comparable period.

Acetabulum↗
PubMed1996

The Frank Stinchfield Award. 3-Dimensional sliding/contact computational simulation of total hip wear.

Polyethylene wear in total hip replacements is a complex, multifactorial process. A tribologically grounded finite element formulation was developed to make quantitative estimates of polyethylene wear in total hip arthroplasty, incorporating the combined influences of contact stress, sliding distance, and a surface specific wear coefficient. For loading and sliding distance inputs taken directly from human gait data, the computational model showed a strong direct proportionality between femoral head size and volumetric wear rate. Other factors being equal, reducing the thickness of the polyethylene liner led to increases in the computed wear rates, but the effect was far less pronounced than the strong increases in wear rate that accompanied head size increases. Compared with human gait inputs, the load and sliding distance inputs for a 23 degrees biaxial rocking hip simulator led to computed wear rates that were 1.7 times as large, and in which the direction of wear was near the cup apex rather than within the posterosuperolateral quadrant. In general, the finite element model's results emphasize the importance of articulation kinematics, especially sliding distance, in the complex process of polyethylene wear in total hip arthroplasty.

Computer Simulation↗
PubMed1996

Primary hybrid total hip arthroplasty: an interim followup.

The senior authors' initial experience with primary hybrid hip replacement in patients with osteoarthritis was studied to evaluate the efficacy of the procedure. Hybrid total hip arthroplasty (uncemented Harris-Galante acetabular component and cemented Iowa precoated femoral component) was performed in 131 consecutive, nonselected hips in 118 patients with the diagnosis of primary osteoarthritis. Followup was performed at 8 to 9 years after the procedure. The average age at the time of the procedure was 68 years (range, 45-87 years). There were 50 men (55 hips) and 68 women (76 hips). At final followup 19 patients (22 hips) had died. The femoral component had been revised for aseptic loosening in 8 hips (6.1%). One additional hip showed definite radiographic loosening. Hence, the prevalence of radiographic femoral failure was 6.9% (9 hips). No acetabular component had been revised for aseptic loosening and no acetabular component had migrated. The senior author continues to perform hybrid total hip arthroplasty in all patients with primary osteoarthritis. However, design modifications have been made in the femoral component that is used.

Aged↗