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Biomedical subjects

W N Capello

Publications and source records attributed to W N Capello.

At least 37 records · Page 2Linked to original sources
PubMed1994

Hydroxyapatite in total hip arthroplasty: five-year clinical experience.

Excellent clinical and radiographic results are seen with HA-coated femoral components at 5-year follow up. These stems are well fixed proximally, and the transmission of stress is noted to occur at the transition from the coated to uncoated stem. Longer follow up is needed to determine if the currently stable HA-coated implants will become threatened by wear debris and subsequent osteolysis, as has been the case in many long-term studies of other hip implants.

Adolescent↗
PubMed1994

Omniflex modular femoral component. Two- to five-year results.

A prospective study was completed on 106 consecutive cementless arthroplasties (94 patients) to determine the clinical and radiographic outcome. Ninety-two hips (81 patients) had complete follow-up data. The average age was 46 years, and the average follow-up period was 41 months (24-63 months). Clinically 94% had no or slight pain. Two patients had activity-limiting thigh pain. Most patients had no or slight limp and walked without support. Patients had similar outcomes regardless of their bone type. Ninety-three percent of hips were radiographically stable. Six were loose; three of those had major intraoperative fractures. Stable stems were characterized by middle and distal zone endosteal condensation and cortical hypertrophy; these occurred primarily in the distal zones for unstable implants. Calcar resorption was noted in 38% of hips with collars and in 68% without collars (p = 0.015). Endosteal erosions were seen in six hips (6.5%) and were related only to the patient's activity level (p = 0.021). Seven hips were revised, two for delayed sepsis, one for loosening after trauma, one for intraoperative fracture, and three for aseptic loosening. The Omniflex implant system provides acceptable but not outstanding results in a wide array of femoral geometries. The early difficulty with femoral fractures has been significantly reduced by using a prophylactic cerclage cable.

Activities of Daily Living↗
PubMed1994

Surgical treatment of the infected hip implant. Two-stage reimplantation with a one-month interval.

Successful treatment of the infected hip prosthesis demands careful planning for infection control and reimplantation. Inadequate surgical debridement dooms well-executed revision surgery to infection failure. Reimplantation is difficult after resection arthroplasty, and this difficulty is increased with longer intervals between resection and reimplantation. Older patients will rehabilitate better if the interval is shorter. The reported protocol successfully compromises between one-stage exchanges and reported two-stage exchanges.

Aged↗
PubMed1993

Prospective study of magnetic resonance imaging and SPECT bone scans in renal allograft recipients: evidence for a self-limited subclinical abnormality of the hip.

We recently reported that typical abnormalities of avascular necrosis (AVN) in magnetic resonance images (MRI) of the hips of asymptomatic renal transplant recipients whose plain radiographs are normal may improve spontaneously and even disappear completely. We present the results of serial bone scans, most of which were performed with single-photon emission computed tomography obtained over periods as long as 24 mo after transplantation in 72 of these patients. Three paired imaging studies (i.e., MR and bone scan performed within 30 days of each other) were available for each of these patients. In three patients, both the MR images and the bone scans showed changes consistent with bilateral AVN within 4 mo after transplantation. All three patients developed hip pain which was bilateral in two and unilateral in one. Two patients (three hips) required surgical intervention at which time AVN was found on pathologic examination of all three hips. None of the remaining 69 patients developed hip pain during the study. However, in nine patients whose MR studies were consistently normal, at least one bone scan was abnormal (13 hips). The presence of AVN was pathologically confirmed in each of the hips subjected to surgery. Where the imaging findings were identical to those in the asymptomatic patients as well as those in whom the imaging abnormality regressed, we suggest that the subclinical imaging abnormalities represent mild AVN, which is reversible in some cases. Since the process was identified in 10 hips by MRI and in 13 hips by bone scan, both studies are needed to detect subclinical AVN. This may be important if treatment of subclinical disease is clearly shown to prevent progression to symptomatic AVN.

Adolescent↗
PubMed1992

Timing of the revision total hip replacement.

The purpose of this article is to define guidelines in regard to timing of revision surgery for total hip replacement. One important variable, in addition to incapacitating pain, is the presence of progressive bone loss associated with loose implants. Indications for revision are presented based on the immediacy of the situation. Timing for revision is categorized as immediate, delayed up to 6 months, delayed beyond 6 months, and elective. Clinical examples of indications are included. Useful diagnostic studies for evaluating the need for revision surgery are discussed. These procedures include several types of arthrography to aid in differential diagnosis.

Diagnosis, Differential↗
PubMed1992

Early clinical experience with hydroxyapatite-coated femoral implants.

As part of a multi-center study, 238 titanium stems that were proximally coated with hydroxyapatite were implanted in 220 patients between January 1988 and December 1989. Ninety-two of these stems in eighty-three patients had a minimum of two years of follow-up, including analysis of the clinical and radiographic data. Clinically, the patients were essentially pain-free before six months and had a low (4 per cent) prevalence of pain in the thigh and a very high composite Harris hip-score (mean, 95 points) at two years. Radiographically, subsidence was detected in 8 per cent of the implants; no implant had more than three millimeters of subsidence. Radiolucencies were characteristically seen around the uncoated distal part of the stem, in 70 per cent of the implants. Contrastingly, radiolucencies were rare in the hydroxyapatite-coated proximal zones and were most often found anteriorly, in only 5 per cent of the implants. Areas of increased formation of cancellous bone were seen beneath femoral cortical bone at the interface between the hydroxyapatite-coated and uncoated parts of the stem, in 67 per cent of the implants. Calcar resorption was found in 49 per cent of the implants. Cortical thickening was present in 17 per cent of the implants at the uncoated distal part of the stem. Two of the 238 femoral implants were revised: one because of infection and one because of aseptic loosening associated with non-union of a subtrochanteric osteotomy.

Adult↗
PubMed1992

Hydroxylapatite-coated hip implants. Multicenter three-year clinical and roentgenographic results.

The application of a thin coating of hydroxylapatite to total hip implants has provided the opportunity to realize stable fixation of a press-fit prosthesis without a porous coating or an intervening fibrous tissue layer. This series consists of 436 total hip arthroplasties, of which 320 cases have a minimum two-year follow-up period and 142 cases have a minimum three-year follow-up period. The femoral prosthesis used was a roughened titanium alloy with a 50-microns surface treatment of hydroxylapatite applied to the proximal one third. The acetabular components implanted included porous-coated implants (132), hydroxylapatite-coated acetabular shells of varying geometries (285), and bipolar implants (16). Analysis of the clinical results demonstrates a mean Harris Hip Score of 93 at six-months postarthroplasty, 95 at one and two years, and 96 at three years. At the three-year follow-up evaluation, 4.2% of patients complained of mild to moderate pain in the operative limb, whereas only 2.2% at two years and 1.4% at three years complained of activity-related thigh pain. The femoral mechanical loosening rate representing stems revised for aseptic loosening (two) plus roentgenographically unstable stems (zero) is 0.46%. Three hydroxylapatite-coated acetabular cups (1%) have shown measurable migration at two years, but none have been revised for aseptic loosening. The roentgenographic evaluation provides evidence for excellent proximal femoral fixation with distal stress transfer. Radiolucencies typically occur around the uncoated distal tip of the femoral stem (74%), but rarely in the proximal hydroxylapatite-coated anterior (3%) and lateral (2%) zones. Femoral cancellous condensation characteristically is seen at the transition zone of hydroxylapatite coated-to-uncoated stems (86%), whereas up to 32% of cases show cortical hypertrophy at the medial distal stem. These roentgenographic changes are progressive from one through three years postoperatively.

Adolescent↗
PubMed1991

Apparent avascular necrosis of the hip: appearance and spontaneous resolution of MR findings in renal allograft recipients.

The sensitivity of magnetic resonance (MR) imaging in the detection of avascular necrosis (AVN) of the hip and natural history of the MR findings were determined prospectively in renal allograft recipients, a group at risk for development of the disease. One hundred four patients were studied up to 24 months after transplantation. In 25 hips in 14 patients, MR findings were consistent with AVN. Pain developed in seven hips in four patients; in each hip, the MR images showed abnormality before the onset of symptoms. Plain radiographs showed abnormality in all hips that became painful; however, the plain radiographs of 17 of 18 asymptomatic hips in which MR imaging showed evidence of AVN showed no abnormality over a mean follow-up period of 16 months. All MR lesions in the symptomatic hips were larger than those in the asymptomatic cohort. MR lesions in seven hips (in five asymptomatic patients) regressed in size; in six hips, the MR images returned to normal. The findings suggest that some patients with MR evidence of AVN of the hip have spontaneous improvement.

Adolescent↗
PubMed1991

Works in progress #6. Total hip arthroplasty using a hydroxyapatite-coated acetabular and femoral component.

The development of alternative methods of implant fixation in primary and revision total hip arthroplasty is ongoing. Porous-coated implants abound; however, concerns surrounding their use still exist. Hydroxyapatite is a calcium phosphate ceramic, which has demonstrated properties in animal studies that make it an attractive alternative for implant fixation. We describe the early clinical and roentgenographic results of a prospective study that utilized a hydroxyapatite-coated stem and cup in 52 patients (58 hips). The average follow-up was 10.4 months (minimum, six months). At one year, 96.2% of the hips had no or slight pain, 95.1% could ambulate with no external support, 82.9% could ambulate unlimited distances, and 87.8% could walk without a limp. The roentgenographic analysis of the hydroxyapatite-coated stems (58) and cups (17) at one year revealed no radiolucencies or radiodense lines adjacent to the hydroxyapatite-coated portion of the prosthesis. None of these stems or cups migrated. We believe that these hydroxyapatite-coated components will provide rapid and enhanced prosthetic fixation and are optimistic that they will help to achieve an excellent clinical result.

Gait↗
PubMed1990

Technical aspects of cementless total hip arthroplasty.

The technique of cementless total hip arthroplasty (THA) places many demands on the surgeon, who must understand the rationale of the prosthetic design to take full advantage of its features. In addition, the surgeon must be able to gauge the quality of the available bone either by preoperative roentgenographic examination or by intraoperative assessment or both. The surgeon must then choose the prosthesis that will predictably fit the individual conditions. Proper instrumentation, practice in a workshop environment, prophylactic wiring of the femur, and postimplantation testing of the prosthesis are important to achieve lasting results of cementless THA.

Bone Density↗
PubMed1989

Fit the patient to the prosthesis. An argument against the routine use of custom hip implants.

There are selected circumstances in which customizing an implant is a solution to a unique problem. However, there are significant reservations as to the need for the routine use of custom hip implants. In fact, it is possible for a customized implant not to function clinically up to the standards that have already been established by the modern, currently available, off-the-shelf implants.

Femur↗
PubMed1989

Classification and management of acetabular abnormalities in total hip arthroplasty.

Total hip arthroplasty, for both primary and revision operations, frequently involves bony abnormalities of the acetabulum. No standard nomenclature currently exists for the definition of acetabular deficiencies. A classification system is presented to assist in the preoperative evaluation and to provide a treatment protocol for these defects.

Acetabulum↗
PubMed1988

Evaluation of metallic osseous implants with nuclear medicine.

Nuclear medicine has proven to have a valuable role in the evaluation of osseous metallic implants, particularly with joint prostheses, but can assist with evaluation of other appliances as well. The nuclear arthrogram has become an invaluable adjunct to simultaneously performed radiographic contrast arthrography. This application has been best evaluated in what is one of the most common of orthopedic prosthesis problems, namely, loosening of total hip prostheses. Experience indicates that both sensitivity and specificity of loosening of the femoral component can be increased to over 90% through combined use of nuclear with radiographic contrast arthrography. Furthermore the combination of routine skeletal scintimaging with the nuclear arthrogram adds a significant dimension to precise localizing of the nuclear arthrographics agent In-111 chloride. Nuclear medicine also plays an important role in further evaluating the presence of infection associated with metallic implants with In-111 WBC preparations being superior to Ga-67 as the radiopharmaceutical tracer. Infection has been detected with a sensitivity of 73% and a specificity of 93% in our series using combined In-111 WBC and simultaneous skeletal imaging with conventional Tc-99m MDP. Acute infections are more readily identifiable than chronic in association with prostheses.

Hip Prosthesis↗
PubMed1986

Preoperative planning of total hip arthroplasty.

Preoperative planning of a total hip replacement is a necessary first step in arthroplasty. If properly done, it can shorten the learning curve for new prosthetic systems, minimize intraoperative guesswork, and decrease surgical time. It also will allow the surgeon to fulfill one of the universal goals of reconstructive surgery--precision with reproducibility.

Hip Joint↗