Use of anchor sutures to repair labral avulsions of the hip: a brief report.
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Acetabulum↗
Biomedical subjects
J J Callaghan
Publications and source records attributed to J J Callaghan.
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↗
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↗
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↗
A 76- year-old woman considering total hip replacement.
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Aged↗
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↗
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↗
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↗
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↗
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↗
Pelvic osteolysis associated with an uncemented acetabular component in total hip arthroplasty.
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Acetabulum↗
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↗
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↗
Richard C. Johnston, M.D. evaluator and practitioner of hip surgery.
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Hip Prosthesis↗
Prospective serial technetium diphosphonate and indium-111 white blood cell labeled imaging in primary uncemented total hip arthroplasty.
Although technetium diphosphonate (TcMP) and Indium-111 white blood cell labeled (Ind-WBC) imaging are reported useful in identifying aseptic and septic loosening in cemented hip arthroplasty, their usefulness has not been identified in uncemented porous coated hip arthroplasty. We attempted to define the natural history of TcMP and Ind-WBC imaging in primary P.C.A. uncemented total hip arthroplasty. Twenty-five hips in 21 patients were scanned immediately postoperatively, at 3 months, 6 months, 12 months, 18 months, and 24 months after surgery with both TcMP and Ind-WBC tracers. Clinical and radiographic follow-up were also obtained at each interval. Intensity and distribution of tracer activity were recorded as well as the time when stabilization occurred around the acetabulum, femoral porous surface areas, and femoral stem tip. Acetabular cup and femoral porous surface areas stabilized in the first year on both TcMP and Ind-WBC imaging. Focal femoral hip activity continued at 24 months in 72% of TcMP and 24% of Ind-WBC images. TcMP and Ind-WBC images used to assess uncemented total hip arthroplasty should not be over interpreted. Although persistent intense activity after one year around the acetabulum and porous surface femoral areas should be considered abnormal for both TcMP and Ind-WBC scans, femoral tip activity is present in the majority of patients, with or without thigh pain, at 24 months on TcMP scans. Tip activity can also persist at 24 months on Ind-WBC images and should be interpreted in conjunction with TcMP images.
Acetabulum↗
Optimal fixation for femoral components: cemented or cementless.
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Bone Cements↗
Reamed surface topography and component seating in press-fit cementless acetabular fixation.
Thirty-eight paired, size-matched, fresh-frozen cadaver acetabulae were used to study reamed surface topography and the seating of on-line versus oversized noncemented components. Four commonly used constructs were considered: on-line reamed and 2-mm oversized hemispherical cups, and on-line reamed and 1-mm oversized dual-radius cups. Reamed surface topography was indexed by three-dimensional surfaces mathematically fitted to digitized castings. Component seating was indexed by the distribution of bone-cup contact and the thickness of the gap between the component backing and the bone. The reamed surfaces were better approximated by slightly blunt ellipsoids than by spheres, especially for the smaller acetabulae. Seating of the on-line hemispherical cups was best near the pole and poorest near the equator, whereas the converse was true for the 1-mm oversized dual-radius cups. The on-line dual-radius cups offered better overall compromise between polar and equatorial contact than did the 2-mm oversized hemispherical components.
Acetabulum↗
Hamstring injuries: radiographic, conventional tomographic, CT, and MR imaging characteristics.
PURPOSE: To review experience with the imaging features of hamstring injuries. MATERIALS AND METHODS: Imaging findings in 18 male and four female patients with clinically proved hamstring injuries were reviewed. The patients' ages ranged from 13 to 61 years (mean, 26 years). Radiography, conventional tomography, computed tomography (CT), and magnetic resonance (MR) imaging were performed. RESULTS: Plain radiographs obtained less than 1 week after injury were normal or showed avulsion of an ischial apophysis. Plain radiographs and conventional tomograms obtained more than 1 week but less than 3 months after injury were confusing, because callus and osteolysis were present. CT helped identify a healing avulsion of an ischial apophysis. MR imaging was helpful no matter how long after the injury it was performed. It provided a means to evaluate muscle, tendon, and bone. CONCLUSION: Familiarity with the variable appearance of hamstring injuries over time and with different modalities facilitates accurate characterization.
Adolescent↗