Biomedical subjects

Paul F Lachiewicz

Publications and source records attributed to Paul F Lachiewicz.

22 records · Page 2Linked to original sources

PubMed2003

Mortality after total hip and knee arthroplasty in a medium-volume university practice.

This study evaluated the mortality after total knee and hip arthroplasties by a single surgeon in a medium-volume university referral practice. For 610 knee arthroplasties, the in-hospital mortality rate was 0.16%, and overall, 2 patients (0.33%) died within the first 90 days. There was no significant difference in mortality at 1 year or 2 years (P =.55) between primary bilateral one-stage and primary unilateral total knee arthroplasties. For 1,108 total hip arthroplasties, the early in-hospital mortality rate was 0.18%, and overall 5 patients (0.45%) died within the first 90 days. For the entire group of arthroplasties, the overall mortality at 1 year and 2 years was significantly less (both P <.05) than the number of expected deaths in the general population.

Adult↗

PubMed2002

Stability of total hip arthroplasty in patients 75 years or older.

Increasing patient age (> 75 years) is a known risk factor for dislocation of total hip arthroplasty. This is a study of total hip arthroplasties by one surgeon in patients 75 years or older to determine the prevalence of dislocation and a review of the surgical options for prevention and treatment of instability in this population. Of 140 primary total hip arthroplasties done in patients 75 years or older who were followed up for at least 1 year, the preoperative diagnosis was osteoarthritis in 82% and the mean followup time was 4 years. The acetabular component was cementless: modular in 121 arthroplasties and cemented in 19 arthroplasties. There were five dislocations (3.5%), but only two were recurrent and the patients were treated successfully by modular component exchange. Bipolar arthroplasty has a lower rate of dislocation, but there are problems with residual pain and high rates of reoperation, wear, and osteolysis. Constrained components may be indicated in older patients with dementia, abductor insufficiency, or failure of modular exchange. Large femoral heads, to increase the range of motion before dislocation occurs, may be used with highly cross-linked acetabular liners. Modular cementless acetabular components are preferable in patients who are 75 years or older. A 28-mm or 32-mm femoral head is recommended, but larger femoral heads should be considered in patients with fractures and for the treatment of recurrent dislocation.

Aged↗

PubMed2002

Survival and polyethylene wear of porous-coated acetabular components in patients less than fifty years old: results at nine to fourteen years.

BACKGROUND: Younger patients (those who are less than fifty years old) have been shown to have a high rate of failure of cemented acetabular components following total hip arthroplasty. In this report, we present the results associated with the use of an uncemented acetabular component in young patients who were evaluated at a minimum of nine years postoperatively. METHODS: Between December 1984 and December 1989, the senior author performed 174 primary total hip arthroplasties with use of a single design of porous-coated acetabular component. Seventy-one of these procedures were performed in fifty-six patients who were younger than fifty years old. Fifty-six of the seventy-one hips were available for radiographic and clinical analysis after a mean duration of follow-up of eleven years. All hips had been treated with a Harris-Galante-I porous-coated acetabular component that had been placed with a line-to-line fit and fixed with a mean of four screws. Clinical analysis was performed with use of the Harris hip score. Standardized anteroposterior radiographs were analyzed with regard to migration, radiolucent lines, pelvic osteolysis, and two-dimensional linear wear of the polyethylene. RESULTS: No metal shell was revised because of aseptic loosening, and no shell was loose at the time of the latest follow-up. A nonprogressive radiolucent line was seen in one zone in ten hips (18%) and in two zones in six hips (11%). No hip had a radiolucent line in all three zones. Pelvic osteolysis was noted in thirteen hips (23%); the osteolysis was observed in the ischium in eleven hips and around the screws in two. Survivorship analysis revealed that the probability of survival of the metal shell was 98% (95% confidence interval, 96.9% to 99.9%) at ten years. The mean rate of linear polyethylene wear (and standard deviation) was 0.15 +/- 0.10 mm/yr (range, 0.02 to 0.59 mm/yr). The wear rate was significantly increased in patients with an excellent Harris hip score (p = 0.004) and a younger age (less than thirty-eight years) (p = 0.026). With the numbers available, no relationship could be detected between the wear rate and the gender or weight of the patient, the polyethylene thickness, the abduction angle, or the femoral neck length. CONCLUSIONS: The fixation and survival of porous-coated acetabular metal shells in patients less than fifty years old was excellent after a mean duration of follow-up of eleven years. The high rate of linear polyethylene wear and the high prevalence of pelvic osteolysis are of serious concern in this patient population. Continued follow-up will be necessary to evaluate the influence of these findings on the longevity of the fixation of this prosthesis.

Acetabulum↗

PubMedDate not supplied

The use of constrained components in total hip arthroplasty.

The use of a constrained component may be appropriate for the surgical treatment of recurrent dislocation due to soft-tissue insufficiency following a total hip arthroplasty. Constrained components usually include a locking mechanism incorporated into the polyethylene acetabular liner to keep the prosthetic femoral head in place. Two different prosthetic designs are available and have been approved by the U.S. Food and Drug Administration. The S-ROM constrained component uses additional polyethylene in the rim, which deforms to more fully capture the femoral head and then is held in place by a metal locking ring. The Howmedica Osteonics constrained component is a tripolar device; its bipolar component articulates with another polyethylene liner. These constrained components transfer hip forces that would otherwise lead to dislocation to the locking mechanism, the liner-shell interface, or the bone-prosthesis interface. These forces may eventually contribute to failure of the component due to loosening, dissociation, breakage, or recurrent dislocation. Studies of these components show a failure rate of 4% to 29% at relatively short-term follow-up.

Arthroplasty, Replacement, Hip↗