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Biomedical subjects

R C Johnston

Publications and source records attributed to R C Johnston.

At least 19 recordsLinked to original sources
PubMed2005

Total hip arthroplasty with cement and without acetabular bone graft for severe hip dysplasia. A concise follow-up, at a minimum of twenty years, of a previous report.

We previously evaluated a cohort of fifty-three patients with severe hip dysplasia (Crowe Type-II, III, or IV subluxation) who underwent a total of sixty-six Charnley total hip arthroplasties. The acetabular component was placed at the anatomic hip center, the superolateral defect was filled with cement, and no bone-grafting was used to supplement the acetabular wall. All but one patient, who was lost to follow-up, were followed until death or for a minimum of twenty years. Radiographic and functional follow-up data were collected prospectively. This retrospective review included twenty-four patients (thirty-four hips) who were alive at a minimum of twenty years following the surgery. Fourteen (22%) of the sixty-five hips underwent revision of a component, with eleven of the revisions performed because of aseptic loosening. Eight of those eleven hips underwent revision because of acetabular loosening alone; two, because of femoral loosening alone; and one, because of loosening of both components. The combined prevalence of revision because of aseptic loosening of the acetabular component and radiographic evidence of failure of the acetabular component was 28% (eighteen hips). With the numbers available, the need for acetabular revision was not associated with the percentage of cement coverage (p = 0.362) or the Crowe classification (p = 0.159). At a minimum of twenty years postoperatively, the survivorship of the acetabular component was 86% +/- 8% with revision because of aseptic loosening as the end point and 82% +/- 10% with revision because of aseptic loosening or radiographic evidence of loosening as the end point. The results that we evaluated at a minimum of twenty years after use of this technique can be compared with the results of other techniques in studies with similar long-term follow-up periods.

Adult↗
PubMed2001

Experimental and computational simulation of total hip arthroplasty dislocation.

Other than fatal pulmonary embolism and deep infection, dislocation following total hip replacement remains probably the most vexing complication to patient and surgeon. Subluxation and dislocation are complex, poorly understood phenomena. Many important questions in this area unfortunately do not lend themselves well to clinical or registry study. Appropriate realistic laboratory models have been lacking. This article synthesizes new work undertaken independently by two groups of biomechanical investigators using very different, but complimentary, methodologies to study the mechanisms of dislocation, and especially the influence of specific design and surgical variables.

Arthroplasty, Replacement, Hip↗
PubMed2001

Dislocation after total hip arthroplasty: a single surgeon's experience.

The purpose of this article is to evaluate the dislocations that occurred in a single surgeon practice over a 26 year period. After extensive research, the authors concluded that dislocation continues to occur long after the initial arthroplasty procedure. Patients should be aware that more than a quarter of dislocations occur 2 years following surgery. Use of modular 22 millimeter components were associated with the highest dislocation rate. These components should be used very cautiously. Constrained liners have helped decrease the dislocation rate following revision for dislocation.

Aged↗
PubMed2001

Comparison of femoral head penetration rates between cementless acetabular components with 22-mm and 28-mm heads.

Between April 1993 and July 1994, the senior author (R.C.J.) performed 151 consecutive primary total hip arthroplasties using a Harris-Galante II acetabular component and a polished Iowa femoral component. In 105 hips, 22-mm head components were used, and in 46 hips, 28-mm head components were used. Femoral head penetration into the acetabular shell was measured using digital edge detection techniques. The group average penetration for the initial 2-year bedding-in period was 0.35 mm/y for the 22-mm and 0.31 mm/y for the 28-mm head components. The long-term rate of penetration into the shell was 0.11 mm/y for the 22-mm heads and 0.17 mm/y for the 28-mm heads, a significant difference (P=.029). The dislocation rate was significantly higher, however, with the 22-mm heads (P=.001). The 22-mm components showed significantly less wear but at the expense of an increase in the prevalence of dislocation.

Acetabulum↗
PubMed2001

Impaction allografting with cement for extensive femoral bone loss in revision hip surgery: a 4- to 8-year follow-up study.

The current study evaluates the 4- to 8-year results of 26 cemented femoral revisions with impaction allografting using a collared femoral component in cases of extensive femoral bone loss. Patients were followed prospectively and were evaluated at an average of 6.0 years after the allograft revision procedure. The average age at the time of surgery was 69.3 years. At final follow-up, 20 patients (20 hips) were living, and 6 patients (6 hips) were deceased. No femoral component rerevisions were performed for any reason in any patient, and none were radiographically loose at final follow-up. There was 1 subsided femoral component of <5 mm, 3 postoperative periprosthetic femoral fractures, and a greater trochanter nonunion rate of 32%. At the current follow-up interval, these cemented femoral revisions with impaction allografting have performed well with excellent clinical and radiographic durability in this difficult patient population. The prevalence of periprosthetic fracture is a significant concern. This study shows durable results using the impaction allografting technique in cases of severe bone loss.

Aged↗
PubMed2001

Prevention of dislocation after hip arthroplasty: lessons from long-term followup.

Regarding dislocation after total hip arthroplasty, prevention is worth an ounce of cure. The current authors evaluated dislocation after total hip arthroplasty during the 26-year practice of one surgeon to identify potential variables that can contribute to the prevention of dislocation. Between 1970 and 1996, dislocation after total hip replacement occurred after 7.2% of primary hip arthroplasty procedures (298 of 4164 primary hip replacements) and 11.2% of revision hip arthroplasty procedures (90 of 803 revision hip replacements). Significant findings included an increase in dislocation when 22-mm modular femoral heads were used and a decrease in dislocation after revision for dislocation when constrained liners were used. An additional finding was that 26% of first time dislocations occurred more than 2 years after surgery. Concerning prevention of dislocation, small head modular femoral components should be used cautiously, and constrained liners should be considered in complex revision cases. Patients should be counseled concerning the potential for dislocation many years after their arthroplasty.

Aged↗
PubMed2001

Revision of a cemented acetabular component to a cementless acetabular component. A ten to fourteen-year follow-up study.

BACKGROUND: Although cementless acetabular components are routinely used in revision hip surgery, few investigators have evaluated the retention and efficacy of these components in the long term. In the current study, the clinical and radiographic outcomes of a series of arthroplasties performed by one surgeon with a cementless acetabular component were assessed at a minimum of ten years. METHODS: From 1986 through 1988, sixty-one consecutive revision total hip arthroplasties were performed in fifty-five patients because of aseptic failure of one or both components of a prosthesis in which both components had been cemented. Twenty-eight patients (thirty-two hips) were alive at a mean of 12.9 years (range, 11.5 to 14.3 years) after the operation. In all of the patients, the acetabular component was revised to a porous-coated Harris-Galante component inserted without cement, and the femoral component was revised to an Iowa component affixed with contemporary cementing techniques. The hips were evaluated clinically and radiographically at a minimum of ten years subsequent to the index revision. No hips were lost to follow-up. RESULTS: None of the acetabular components required revision because of aseptic loosening. Two hips (3%) demonstrated radiographic evidence of aseptic loosening of the acetabular component. The polyethylene liner was exchanged during the follow-up period in eight hips. CONCLUSION: After a minimum of ten years of follow-up, cementless acetabular fixation in revision hip arthroplasty had produced durable results that were markedly better than those reported for acetabular fixation with cement.

Acetabulum↗
PubMed2001

Charnley total hip arthroplasty with use of improved cementing techniques: a minimum twenty-year follow-up study.

BACKGROUND: In total hip arthroplasty, techniques for cementing the femoral component have changed over time. The purpose of the present study was to determine whether a cementing technique that includes use of a distal cement plug and retrograde filling of the femoral canal affects the fixation of the femoral component at a minimum of twenty years after the operation. METHODS: Between 1976 and 1978, the senior one of us (R.C.J.) performed 357 total hip arthroplasties with use of a Charnley flatback polished femoral stem and a contemporary cementing technique (insertion of a distal cement plug and retrograde filling of the femoral canal with cement) in 320 patients. The results after a minimum follow-up of twenty years were compared with those after 330 total hip arthroplasties performed, between 1970 and 1972, with the same femoral stem by the same surgeon with use of a hand-packing technique of cementing in 262 patients. The clinical and radiographic evaluation as well as the duration of follow-up were identical in the two groups. RESULTS: In the group managed with the contemporary cementing technique, six (1.8%) of the 336 hips that had not been lost to follow-up or revised because of infection or dislocation were revised because of aseptic loosening of the femoral component. Of the ninety-one hips in the eighty-two patients who were alive at a minimum of twenty years, five (5%) had a revision because of aseptic loosening of the femoral component. Only one hip was revised during the fifteen-to-twenty-year follow-up interval. (The revision was performed because of a fracture of the femoral component.) The rate of failure when radiographic signs of loosening were included was 4.8% (sixteen of 336 femoral components that had not been revised because of infection or dislocation) for the group managed with the contemporary cementing technique compared with 6.3% (twenty of 319 hips) in the group managed with the hand-packing technique; the difference was not significant (p = 0.40). Adequate filling of the femoral canal with cement was found to be associated with improved survival of the femoral component (p = 0.03). CONCLUSIONS: While no significant difference between the two cementing techniques could be identified, the ability to deliver adequate cement around the femoral component was more predictable with the contemporary cementing technique. In addition, the prevalence of loosening of the femoral component was low with use of either technique, a tribute to the Charnley flatback polished femoral component design.

Adult↗
PubMed2000

MAD3 encodes a novel component of the spindle checkpoint which interacts with Bub3p, Cdc20p, and Mad2p.

We show that MAD3 encodes a novel 58-kD nuclear protein which is not essential for viability, but is an integral component of the spindle checkpoint in budding yeast. Sequence analysis reveals two regions of Mad3p that are 46 and 47% identical to sequences in the NH(2)-terminal region of the budding yeast Bub1 protein kinase. Bub1p is known to bind Bub3p (Roberts et al. 1994) and we use two-hybrid assays and coimmunoprecipitation experiments to show that Mad3p can also bind to Bub3p. In addition, we find that Mad3p interacts with Mad2p and the cell cycle regulator Cdc20p. We show that the two regions of homology between Mad3p and Bub1p are crucial for these interactions and identify loss of function mutations within each domain of Mad3p. We discuss roles for Mad3p and its interactions with other spindle checkpoint proteins and with Cdc20p, the target of the checkpoint.

Calcium-Binding Proteins↗
PubMed2000

Charnley total hip arthroplasty with cement. Minimum twenty-five-year follow-up.

BACKGROUND: This report presents the results of the senior author's initial twenty-five-year experience with the use of Charnley total hip arthroplasty with cement. The purpose of this paper was to evaluate the long-term results of total hip arthroplasty. METHODS: Between July 1970 and April 1972, the senior author (R. C. J.) performed 330 Charnley total hip replacements with cement using a hand-packing cement technique in 262 patients. Fifty-one patients (sixty-two hips) who were alive at least twenty-five years post-operatively were evaluated from a clinical standpoint with use of a standard-terminology questionnaire. The average age of this group at the time of surgery was fifty-six years (range, thirty-five to seventy-one years) compared with sixty-five years (range, twenty-one to eighty-nine years) for the entire group. All patients were evaluated for radiographic changes at the time of their most recent follow-up. Of the fifty-one patients (sixty-two hips) who were alive at least twenty-five years postoperatively, thirty-one (thirty-six hips) had a follow-up radiograph made at a minimum of twenty-five years after the surgery. The average duration of radiographic follow-up for the fifty-one patients was 22.7 years (range, two to twenty-seven years). RESULTS: Of the sixty-two hips in the fifty-one patients who were alive at least twenty-five years postoperatively, fourteen (23 percent) had been revised. Three (5 percent) had the revision because of loosening with infection; eleven (18 percent), because of aseptic loosening; and none, because of dislocation. The prevalence of revision due to aseptic loosening of the acetabular component in all 316 hips (excluding those that were lost to follow-up or that were revised for infection or dislocation) was 6 percent (eighteen hips), whereas the prevalence in the fifty-nine hips (excluding the three revised for infection) in the patients who were alive at least twenty-five years after the arthroplasty was 15 percent (nine hips). The prevalence of revision because of aseptic loosening of the femoral component in all 316 hips was 3 percent (nine hips), and the prevalence in the fifty-nine hips in the living patients was 7 percent (four hips). In the group of living patients, osteolysis occurred in Gruen zone 1 or 7 in thirty-three hips and in Gruen zones 2 through 6 in two hips. Ballooning acetabular osteolysis occurred in five hips. Of the 327 hips for which the outcome was known after a minimum of twenty-five years, 295 (90 percent) had retained the original implants until the patient died or until the most recent follow-up examination. Of the sixty-two hips in patients who lived for at least twenty-five years after the surgery, forty-eight (77 percent) had retained the original prosthesis. CONCLUSIONS: Our follow-up study at twenty-five years following Charnley total hip arthroplasty with cement demonstrates the durability of the results of the procedure. These results should provide a means for comparison with the results of newer cementing techniques as well as those associated with newer cemented and cementless hip designs.

Aged↗
PubMed2000

Cemented rotating-platform total knee replacement. A nine to twelve-year follow-up study.

BACKGROUND: Although the LCS (low contact stress) rotating-platform mobile-bearing knee replacement has been used extensively, there have been few intermediate or long-term clinical and radiographic follow-up studies evaluating the device. The purpose of this study was to report the nine to twelve-year results of a consecutive series of patients who had a primary total knee replacement performed with this device. METHODS: Between November 1985 and November 1988, the senior author (R. C. J.) performed 119 consecutive total knee arthroplasties in eighty-six patients with LCS rotating-platform femoral and tibial components and a Townley all-polyethylene dome patellar component. All components were fixed with cement. The average age of the patients at the time of the operation was seventy years (range, thirty-seven to eighty-eight years). Fifty-two patients (seventy-six knees) were female, and thirty-four patients (forty-three knees) were male. The patients were evaluated with clinical knee ratings and radiographic analysis nine to twelve years following the knee replacement. RESULTS: At the time of the nine to twelve-year follow-up, sixty-four patients (eighty-six knees) were alive, eighteen patients (twenty-eight knees) had died, and four patients (five knees) had been lost to follow-up. Of the 114 knees in the eighty-two patients for whom the final outcome was known, none required a reoperation and none had a dislocation of the mobile-bearing prosthesis. For the forty-five patients (sixty-six knees) who returned for final clinical and radiographic follow-up examinations at nine to twelve years, the average clinical and functional Knee Society ratings were 30 points (range, 2 to 70 points) and 44 points (range, 0 to 80 points) preoperatively and 90 points (range, 63 to 102 points) and 75 points (range, 30 to 100 points) at the final follow-up evaluation. The average Hospital for Special Surgery knee rating was 57 points (range, 28 to 80 points) preoperatively and 84 points (range, 59 to 97 points) at the final follow-up evaluation. The average active range of knee flexion was from 0 degrees (range, 0 to 10 degrees) to 102 degrees (range, 15 to 120 degrees) at the final follow-up evaluation. Seven of the sixty-six knees were painful anteriorly. There was no periprosthetic osteolysis and no evidence of loosening on follow-up radiographs. CONCLUSIONS: After nine to twelve years of follow-up, the cemented LCS rotating-platform knee replacement was found to be performing well, with durable clinical and radiographic results.

Adult↗
PubMed1999

The John Charnley Award. Practice surveillance: a practical method to assess outcome and to perform clinical research.

The senior author systematically began collecting preoperative and postoperative data on all the total hip arthroplasties he performed starting in July 1970. The data collected represent a 26-year experience using practice surveillance (preoperative and regular interval postoperative collection and analysis of outcomes) as a method to document the outcome of the total hip arthroplasty procedure and as a method to evaluate the need for changes in the procedure. As the senior author made few selected changes in the operative procedure during the followup period, the primary author has been able to evaluate the change in outcome based on these changes. The six studies reported in the current study show the durability of the long-term results of cemented total hip arthroplasty, the improvement in radiographic reproducibility obtained on the femoral side of the construct with improved cementing techniques, the deleterious effects of using cable to reattach the greater trochanter, the deleterious effects of changing femoral component design that included a change in surface finish, the improvement in acetabular fixation using cementless fixation, and the optimization of bearing surface wear using smaller diameter femoral heads. All of these findings have been incorporated into the primary surgeon's practice based on this practice surveillance. As shown, practice surveillance also has provided a tool for performing clinical research. Although practice surveillance of controlled cohorts never will supplant prospective randomized clinical trials in evidence based medicine, it should help each surgeon with his or her own practice and can be used as an important research tool to study the optimization of outcomes of a surgical procedure.

Adult↗
PubMed1999

One-stage revision surgery of the infected hip. A minimum 10-year followup study.

Between 1977 and 1983, 24 one-stage revision surgeries were performed for septic failure of a total hip arthroplasty in 24 patients by one surgeon. Twelve patients died and none were lost to followup at a minimum of 10 years after the procedure. Infection reoccurred around two hips (8.3%). If the selected criteria (patients without draining sinuses, without immunocompromise, and with adequate bone quality after debridement) and the standard approach (meticulous debridement, use of antibiotic-impregnated cement, and use of 3 to 6 months postoperative oral antibiotic therapy) used in this study are implemented, direct exchange of an infected total hip arthroplasty construct is a reasonable and cost-effective alternative for some patients with infection after total hip arthroplasty.

Adult↗
PubMed1999

The effects of surface roughness and polymethylmethacrylate precoating on the radiographic and clinical results of the Iowa hip prosthesis. A study of patients less than fifty years old.

BACKGROUND: The purpose of the present study was to compare the results associated with two different surface finishes (bead-blasted and grit-blasted) for Iowa femoral components used in total hip arthroplasties performed between January 1979 and June 1991 in patients who were less than fifty years old. METHODS: Between January 1979 and December 1985, thirty-six primary total hip replacements were performed in twenty-five patients with insertion of a bead-blasted Iowa femoral component (average surface roughness, 0.8 micrometer) with cement and insertion of a titanium-backed acetabular component (thirty-five hips) or non-metal-backed acetabular component (one hip) with cement. Between January 1986 and June 1991, forty-five primary total hip replacements were performed in thirty-seven patients with use of a precoated grit-blasted Iowa femoral component (average surface roughness, 2.1 micrometers) and a Harris-Galante-I porous ingrowth acetabular component (forty-one hips) or an Osteonics component (four hips). The only change in the design of the femoral component (other than the surface finish) between the two consecutive series was the addition of polymethylmethacrylate precoating to the proximal third of all forty-five grit-blasted stems and modularity of the femoral head of the last eight grit-blasted stems. RESULTS: No hip was lost to follow-up. The duration of radiographic follow-up of the hips treated with the bead-blasted component averaged 11.3 years (range, ten to sixteen years) postoperatively, whereas that of the hips treated with the precoated grit-blasted component averaged 8.2 years (range, five to eleven years). Two (6 percent) of the bead-blasted femoral components were revised because of aseptic loosening compared with eight (18 percent) of the precoated grit-blasted components. Four bead-blasted components (11 percent) were either radiographically loose or were revised because of loosening compared with eleven precoated grit-blasted components (24 percent). Kaplan-Meier survivorship curves evaluated with log-rank analysis revealed that the bead-blasted Iowa femoral components were revised because of aseptic loosening (p = 0.0184) and were radiographically loose (p = 0.0068) less often than the precoated grit-blasted Iowa femoral components. CONCLUSIONS: The findings of the present study have led the senior ones of us to resume using femoral components with a polished surface and fixed with cement.

Adolescent↗
PubMed1999

Unicompartmental knee replacement. A minimum 15 year followup study.

One hundred forty Marmor cemented unicompartmental knee replacements were inserted in 103 patients between 1975 and 1982. Fifty-two patients were women and 51 were men. One hundred twenty-five were medial compartment knee replacements and 15 were lateral knee replacements. At minimum 15 year followup 34 patients with 48 knee replacements were living; only four patients with four knee replacements were lost to followup. Average preoperative and final followup Hospital for Special Surgery knee scores were 57 and 82 points, respectively for the knees of living patients. Average preoperative and final followup Knee Society clinical and Knee Society functional scores were 31 and 42, and 85 and 71 points, respectively. For all knees, 10.2% (14 knees) were revised [4.4% (six knees) for tibial loosening, 5.1% (seven knees) for disease progression, and .7% (one knee) for pain]. For patients living 15 years, 12.5% (six knees) were revised [2.1% (one knee) for tibial loosening, and 10.4% (five knees) for disease progression]. Revision for failure of fixation of these unicompartmental replacements was comparable with that reported for fixed bearing total knee replacement. Disease progression (46%; 62 of 136 knees) and tibial subsidence with wear (10.4%; 15 of 136 knees, five of which required revision) were the major long term problems in this group of patients.

Activities of Daily Living↗
PubMed1998

Hybrid total hip arthroplasty in patients under the age of fifty: a five- to ten-year follow-up.

In 37 patients, 45 total hip replacements were performed using contemporary cementing techniques, an uncemented Harris-Galante I acetabular component and a cemented precoated Iowa femoral component in patients under the age of 50 at the time of their surgery; 36 patients with 43 hybrid hips were living, 1 patient with 2 hybrid hips was decreased. No patients were lost to follow-up. At 5- to 10-year follow-up, eight hips were revised for aseptic loosening. No acetabular components, and eight femoral components (18%) were revised for aseptic loosening. When looking at radiographic results, including revision as well as those components that were probably or definitely loose on radiographs, 0 acetabular components and 11 femoral components (24%) were radiographically loose. These results demonstrate the excellent durability of the uncemented Harris-Galante acetabular component in the younger patient. However, the Iowa grit-blasted methyl methacrylate precoated femoral component had a magnitude increase in the prevalence of revision for aseptic femoral loosening when compared to the senior author's long-term Charnley results in this age group. The authors attribute the failure to the rough surface finish applied to the femoral component. However, the polymethyl methacrylate proximal precoating and the femoral component design may also contribute to the femoral failures.

Adult↗
PubMed1998

Salvage of total hip instability with a constrained acetabular component.

Between April 1988 and February 1993, 101 constraining acetabular components were implanted into 98 patients. One patient was lost to followup at 8 months. Otherwise, all patients were observed until death or for at least 2 years minimum followup. The average clinical followup for the living patients was 61 months (range, 24-97 months). Indications for the use of the constrained acetabular components were recurrent dislocation (an average of six dislocations, range 2-20) in 56 cases, intraoperative instability in 38 cases, and neurologic impairment in seven cases. For the entire group there were four cases of recurrent dislocation or failure of the component (4%). For the cases where this component was used for recurrent dislocation, 96% (54 of 56 cases) had no additional dislocations. Radiographically, at this short term followup, there was no evidence of an increased incidence of femoral or acetabular component loosening. The authors recommend judicious use of this component as a salvage measure for desperate cases of hip instability during or after total hip arthroplasty.

Acetabulum↗