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Biomedical subjects

Richard C Johnston

Publications and source records attributed to Richard C Johnston.

At least 19 recordsLinked to original sources
PubMed2007

Total hip arthroplasty with a cemented, polished, collared femoral stem and a cementless acetabular component. A follow-up study at a minimum of ten years.

BACKGROUND: Recent studies have suggested that cemented femoral components with a polished surface may provide superior long-term fixation when compared with femoral components with a roughened surface. The purpose of this study was to evaluate the results of total hip arthroplasty with a cemented femoral component with a polished surface finish and compare them with the results of total hip arthroplasty performed with a similar design of cemented femoral component with a rougher surface finish. METHODS: We retrospectively reviewed a consecutive group of 132 patients (149 hips) in whom primary total hip arthroplasty had been performed by one surgeon using a cemented collared femoral component with a polished (0.1-microm Ra) surface finish and a cementless acetabular component. Ninety-eight patients (115 hips) were followed for a minimum of ten years. We compared the survivorship of this prosthesis with that of a femoral component of similar design but with rougher surfaces (matte or grit-blasted). RESULTS: No polished stems were revised because of aseptic loosening or demonstrated radiographic evidence of loosening; however, eight hips (5.4%) with a polished stem demonstrated osteolysis distal to the greater or lesser tro-chanter. In contrast, six stems (2.0%) with a matte surface finish of 0.8-microm Ra were revised because of aseptic loosening, and an additional five stems were seen to be loose radiographically. Eleven stems (9.2%) with a grit-blasted surface finish of 2.1-microm Ra were revised because of aseptic loosening, and an additional four stems were seen to be loose radiographically. The difference in the prevalence of revision due to aseptic loosening between the group with the 0.1-microm Ra surface and the group with the 2.1-microm Ra surface was significant (p = 0.001), as was the difference between the prevalence of revision due to aseptic loosening between the group with the 0.8-microm Ra surface and the group with the 2.1-microm Ra surface (p = 0.001). No cups were revised because of aseptic loosening, and one hip had radiographic signs of acetabular loosening. CONCLUSIONS: This study demonstrated excellent durability of a prosthesis consisting of a cemented, collared, polished femoral component and a cementless acetabular component. While no hips were revised because of aseptic loosening, distal femoral osteolysis was observed in eight hips (5.4%), a higher prevalence than has been reported by others after similar durations of follow-up of tapered, collarless, polished femoral components.

Adult↗
PubMed2006

Results of Charnley total hip arthroplasty with use of improved femoral cementing techniques. a concise follow-up, at a minimum of twenty-five years, of a previous report.

UNLABELLED: The current study was performed to determine the status, at a minimum of twenty-five years, of a prospective, single-surgeon series of patients treated with primary Charnley total hip arthroplasty with a contemporary femoral cementing technique that included use of a distal cement plug and a retrograde cement-delivery system. Since our review at a minimum of twenty years postoperatively, two primary total hip prostheses were revised (one because of acetabular loosening, and one because of femoral loosening). Of the original cohort of 357 hips (320 patients), ten (2.8%) had revision of the femoral stem because of aseptic loosening. Forty-nine patients (fifty-two hips, 14.6%) who had been in the initial study group were still living at the time of the present review. Five hips (10%) in living patients had required a femoral revision because of aseptic loosening. Including those that were revised, eight femoral components (17%) in living patients were seen to be loose radiographically. Although this study demonstrates the remarkable durability of the femoral fixation obtained with the polished flatback Charnley prosthesis and the contemporary cementing technique, there was some deterioration of the results with time. These results provide a standard for comparison with cementless fixation after hips treated with that technique have been followed for a similar duration. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions to Authors for a complete description of levels of evidence.

Adult↗
PubMed2005

Acrylic bone cement: clinical development and current status in North America.

This article discusses issues surrounding acrylic bone cement and covers functional results, mechanism and definition of failure, design issues, wear and alternate bearing surfaces, revision, and evolution of concepts regarding infection, dislocation, thromboembolic issues, surgical approach, bone loss and bone grafts, and finally a couple of problems the author sees for the future.

Arthroplasty, Replacement↗
PubMed2005

The John Insall Award: unicompartmental knee replacement: a minimum twenty-one-year followup, end-result study.

UNLABELLED: We report the results of a minimum 21-year followup of a consecutive series of 103 patients who had 136 Marmor cemented unicompartmental knee replacements done between 1975 and 1982. Patients were evaluated clinically and radiographically. At minimum 21-year followup 14 patients (19 knees) were alive, 87 patients (115 knees) had died, and only two patients (two knees) were lost to followup. The average age at surgery was 70.9 years. The average followup Hospital for Special Surgery knee score was 58. The average Knee Society final followup clinical and functional scores averaged 72 and 53 points, respectively. Nineteen knees (14%) were revised during the 21-year followup period: nine for progression of disease, eight for loosening, and two for pain, at an average of 10.6 years (range, 1-22 years). Of the 19 knees in the 14 patients who were still alive at final followup, seven (37%) were revised: two for tibial loosening, four for disease progression, and one for pain. Unicompartmental knee replacements in this relatively older age group of patients performed well at minimum 21-year followup. Although we are encouraged by these results, only 22% were done in patients who were younger than 65 years at the time of surgery and the results in this group were significantly less durable. LEVEL OF EVIDENCE: Therapeutic study, Level IV-1 (case series). See the Guidelines for Authors for a complete description of levels of evidence.

Aged↗
PubMed2005

Cemented rotating-platform total knee replacement. a concise follow-up, at a minimum of fifteen years, of a previous report.

We previously evaluated 119 consecutive total knee arthroplasties that were performed in eighty-six patients with use of the cemented LCS (low contact stress) rotating-platform system with an all-polyethylene patellar component. The average age of the patients at the time of surgery was seventy years (range, thirty-seven to eighty-eight years). The purpose of this study was to report the updated results at a minimum follow-up of fifteen years. Thirty-seven patients (fifty-three knees) were living, and no patient was lost to follow-up. No knee was revised because of loosening, osteolysis, or wear. Three knees required a reoperation (two for periprosthetic fractures and one for infection). No component was revised as a part of the reoperations. Osteolysis was present in three knees. No knee had radiographic signs of component loosening, and there were no dislocated bearings. The average range of motion was from 1 degrees of extension to 105 degrees of flexion. The average clinical and functional Knee Society scores were 43 and 49, respectively, at the preoperative evaluation and 85 and 58 at the time of the final follow-up. We concluded that the cemented LCS rotating-platform knee performed well, with durable clinical and radiographic results at a minimum follow-up of fifteen years.

Activities of Daily Living↗
PubMed2004

Are all cementless acetabular components created equal?

The cementless acetabular components used over the past 2 decades have varied in type of ingrowth fixation, supplemental fixation, locking mechanisms, and bearing surface. We evaluated 15-year follow-up results from 2 cementless acetabular components: the Harris-Galante I (HG; Zimmer, Warsaw, IN) and the PCA (Howmedica, Rutherford, NJ), in terms of revision and radiographic loosening. Three of the 120 HG I acetabular components were revised for wear and osteolysis without loosening. Seventeen of the 100 PCA components were revised for aseptic loosening (with or without osteolysis). Including those cases revised, 21 PCA acetabular components were loose radiographically, and no HG I component was loose. At least with these 2 first-generation designs, differences were seen in performance of the acetabular component in terms of revision and loosening at 15 years.

Adult↗
PubMed2004

Use of a constrained tripolar acetabular liner to treat intraoperative instability and postoperative dislocation after total hip arthroplasty: a review of our experience.

Constrained acetabular components have been used to treat certain cases of intraoperative instability and postoperative dislocation after total hip arthroplasty. We report our experience with a tripolar constrained component used in these situations since 1988. The outcomes of the cases where this component was used were analyzed for component failure, component loosening, and osteolysis. At average 10-year followup, for cases treated for intraoperative instability (2 cases) or postoperative dislocation (4 cases), the component failure rate was 6% (6 of 101 hips in 5 patients). For cases where the constrained liner was cemented into a fixed cementless acetabular shell, the failure rate was 7% (2 of 31 hips in 2 patients) at 3.9-year average followup. Use of a constrained liner was not associated with an increased osteolysis or aseptic loosening rate. This tripolar constrained acetabular liner provided total hip arthroplasty construct stability in most cases in which it was used for intraoperative instability or postoperative dislocation.

Adult↗
PubMed2004

Results of Charnley total hip arthroplasty at a minimum of thirty years. A concise follow-up of a previous report.

The purpose of the current study was to update the results of a prospective, single-surgeon series of primary Charnley total hip arthroplasties performed with cement. This investigation is one of the first studies in which hips treated with total hip arthroplasty with cement were followed for a minimum of thirty years. Twenty-seven patients (thirty-four [10.3%] of the hips in the initial study group) were alive at a minimum of thirty years postoperatively. These patients served as the focus of the present study. Revision because of aseptic loosening of the acetabular component was performed in 7.3% (twenty-three) of the hips from the original study group (excluding those revised because of infection or dislocation) and 26% (eight) of the hips in the living cohort. Revision because of aseptic loosening of the femoral component was performed in 3.2% (ten) of the hips from the original study group (excluding those revised because of infection or dislocation) and 10% (three) of the hips in the living patients. Since the twenty-five-year review, three hips were revised (one because of acetabular loosening, one because of femoral loosening, and one because of instability). This end-result study demonstrated the remarkable durability of cemented Charnley total hip replacements over a span of three decades, with 88% of the original prostheses intact at the time of the final follow-up or at the patient's death.

Aged↗
PubMed2004

A constrained liner cemented into a secure cementless acetabular shell.

BACKGROUND: Constrained acetabular components have been used to treat hips with recurrent instability following total hip arthroplasty and hips that demonstrate instability during revision surgery. In such hips, when a secure cementless acetabular shell is present, the surgeon can cement a constrained liner into the existing shell. The purpose of this study was to evaluate the clinical and radiographic outcome of this technique with use of a tripolar constrained liner that was cemented into a well-fixed cementless acetabular shell. METHODS: Between 1988 and 2000, constrained liners were cemented into thirty-one well-fixed cementless acetabular shells at three centers. The average age of the patients at the time of the index surgery was 72.1 years, and the indications for the procedure were recurrent hip instability in sixteen hips and intraoperative instability in fifteen hips. The patients were evaluated with respect to the clinical outcome and radiographic evidence of shell loosening and osteolysis. RESULTS: At an average duration of follow-up of 3.9 years, twenty-nine liners (94%) were securely fixed in the cementless shells and two constrained liners had failed. One liner failed because it separated from the cement, and one failed because of fracture of the capturing mechanism. Both hips were successfully revised with another cemented tripolar constrained liner. No acetabular component demonstrated radiographic evidence of progressive loosening or osteolysis. CONCLUSIONS: A constrained tripolar liner cemented into a secure, well-positioned cementless acetabular shell provides stability and durability at short-term follow-up. Careful attention to the preparation of the liner, the sizing of the component, and the cementing technique are likely to reduce the failure of this construct, which can be used for difficult cases of total hip instability.

Acetabulum↗
PubMed2004

Salvage of a recurrently dislocating total hip prosthesis with use of a constrained acetabular component. A concise follow-up of a previous report.

We previously reported the results at a mean of five years following the use of a tripolar constrained acetabular component to treat recurrently dislocating total hip prostheses. In this study, we report the results after longer follow-up, with emphasis on the prevalence of implant loosening, osteolysis, and later recurrent instability. Fifty-five patients treated with a total of fifty-six constrained acetabular components because of recurrent dislocations of a total hip prosthesis (average, six dislocations; range, two to twenty dislocations) were followed for an average of 10.2 years (range, 7.0 to 13.2 years) or until death. Four (7%) of the fifty-six hips had a subsequent dislocation or failure of the device. Three femoral components (5%) and two acetabular components (4%) were revised because of aseptic loosening. One hip was revised because of osteolysis. We concluded that this constrained acetabular component provides durable protection against additional dislocations without substantial deleterious effects on component fixation. We use this device to treat recurrent dislocation when other modalities are unlikely to be effective.

Acetabulum↗
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

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

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

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

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↗