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Charles A Rockwood

Publications and source records attributed to Charles A Rockwood.

13 recordsLinked to original sources
PubMed2007

Compaction bone-grafting in prosthetic shoulder arthroplasty.

BACKGROUND: Compaction bone-grafting has been suggested as a means of improving the stability of the humeral component in shoulder arthroplasty, but the clinical and radiographic results of the procedure have not been reported in the literature, to our knowledge. To address this deficit, we report on a series of shoulder arthroplasties performed with compaction bone-grafting to secure humeral component fixation. These prostheses were implanted in shoulders demonstrating a suboptimal interference fit of the humeral component. METHODS: Fifty-eight shoulders in fifty-three patients were treated with prosthetic shoulder arthroplasty that included compaction bone-grafting. Clinical assessments were performed at regular intervals with use of visual analog scales for pain, shoulder comfort and function, and overall quality of life, and with use of patient self-assessments including the American Shoulder and Elbow Surgeons Score and the validated Simple Shoulder Test. A detailed radiographic analysis was performed by three raters to determine whether radiolucent lines were present immediately postoperatively and at a later follow-up interval. The humeral tilt angle was determined by measuring the angle between the humeral axis and the component. Subsidence was also evaluated. The mean of the raters' measurements was used in the analysis. RESULTS: The mean duration of follow-up was sixty-nine months (range, twenty-six to 148 months). No loose stems were observed, and no humeral component was revised. At the time of follow-up, there was significant improvement in the Simple Shoulder Test scores and all visual analog scores (p < 0.0001 in each instance). Thirty-four stems had no radiolucent line at the time of follow-up, and the mean maximum thickness of the lucent lines was 0.21 mm in the entire group of fifty-eight shoulders. Most lucent lines occurred near the distal stem tip. The mean tilt of the valgus and varus humeral components was 2.2 degrees and 2.6 degrees , respectively, on the immediate postoperative radiographs. No humeral component shifted from varus to valgus or vice versa. The duration of follow-up was not correlated with the maximum thickness of the humeral component lucency, and the presence or absence of a prosthetic glenoid was also unrelated to the maximum thickness of the lucency. CONCLUSIONS: Compaction bone-grafting in shoulder arthroplasty can yield stable and durable fixation of the humeral component, as seen clinically and radiographically, without use of cement. Our findings provide evidence that compaction bone-grafting in shoulder arthroplasty is an option to ensure intermediate-term fixation (at a mean of five years) of humeral components that have a suboptimal fit.

Adult↗
PubMed2006

Shoulder arthroplasty in cases with avascular necrosis of the humeral head.

Avascular necrosis (AVN) is a relatively uncommon cause of glenohumeral arthritis. Previous retrospective reviews of shoulder arthroplasty for AVN have shown very good results in small numbers of patients. This study prospectively evaluated a consecutive series of 21 shoulders in 19 patients treated with the same modular prosthesis at a single institution. Of the shoulders, 8 developed AVN after a proximal humeral fracture, 1 was associated with a massive rotator cuff tear, 10 developed after corticosteroid therapy, and 2 were idiopathic. The patients, 14 women and 5 men, with a mean age of 54 years, were followed up for a mean of 4.7 years (range, 2 to 8 years). Hemiarthroplasty was performed in 15 shoulders, whereas 6 required total shoulder arthroplasty. Assessment included visual analog scales, the Simple Shoulder Test, and the American Shoulder and Elbow Surgeons Shoulder Score Index (SSI). Physical examination was performed, and radiographs were obtained. The visual analog scale scores for pain and function improved significantly after surgery (P < .01). The mean SSI score rose from 36 to 81 (where 0 indicates the worst outcome and 100 indicates the best outcome). The mean number of positive responses on the Simple Shoulder Test increased from 3 to 10. Mean active elevation increased from 88 degrees to 123 degrees . External rotation improved from 7 degrees to 34 degrees , and internal rotation improved from L4 to T12. No difference in outcome was noted based on age or sex. Patients with steroid-related or idiopathic AVN had greater pain and functional impairment preoperatively (mean SSI score, 26) than those with prior fracture or rotator cuff tear (mean SSI score, 49) (P < .01). Postoperatively, however, these groups fared equally well (mean SSI score, 78 vs 82). Shoulder arthroplasty for AVN produces good pain relief and function, although a concurrent series with osteoarthritis yielded better results. Forward elevation did not approach normal as had been previously reported.

Adult↗
PubMed2006

Treatment of glenohumeral arthritis with a hemiarthroplasty: a minimum five-year follow-up outcome study.

BACKGROUND: Glenohumeral hemiarthroplasty is well established as a method to treat glenohumeral arthritis. This study was designed to report longer-term results and to provide a decision model to assist surgeons in achieving successful outcomes. Our selection strategy for hemiarthroplasty included shoulders with (1) a concentric glenoid with eburnated bone, (2) a nonconcentric glenoid that could be converted to a smooth concentric surface, and (3) a humeral head centered within the glenoid after soft-tissue balancing. METHODS: Fifty-seven consecutive patients (sixty-four shoulders) who had osteoarthritis of the glenohumeral joint, without advanced disease in the glenoid, were treated with hemiarthroplasty. In each instance, a modular prosthesis was implanted. Clinical assessment was performed preoperatively and at one-year intervals postoperatively for at least five years with use of patient self-assessment instruments, including the American Shoulder and Elbow Surgeons questionnaire, the Simple Shoulder Test, and a visual analog pain scale. A detailed radiographic analysis was performed to determine the presence of glenohumeral subluxation, periprosthetic radiolucency, and glenoid bone loss. RESULTS: Forty-three patients (fifty shoulders) were followed for a minimum of five years (mean, 7.5 years). Of the remaining fourteen patients (fourteen shoulders), ten were lost to follow-up, three had died, and one was excluded. For the Simple Shoulder Test, and for every visual analog scale measure, the results at the final follow-up evaluation were significantly better than the preoperative results (p < 0.0001 for each). The mean Simple Shoulder Test score at the time of the final follow-up was 9.4 positive responses compared with 9.7 positive responses at the two-year evaluation (p = 0.32), and the mean visual analog scale score for pain was 18.6 points compared with 14.9 points at two years (p = 0.45). Radiographic analysis showed the majority of stems had either no lucency or lucencies only near the tip of the stem. Glenoid bone loss and subluxation improved postoperatively, and the results were maintained at the final follow-up evaluation. CONCLUSIONS: Shoulder hemiarthroplasty provides sustained good-to-excellent pain relief and functional improvement at five to ten years postoperatively in carefully selected patients with osteoarthritis.

Adult↗
PubMed2003

Humeral fixation by press-fitting of a tapered metaphyseal stem: a prospective radiographic study.

BACKGROUND: The technique of shoulder arthroplasty requires a method for securely and durably fixing the humeral component in the medullary canal of the proximal part of the humerus. As an alternative to fixation by cementing or tissue ingrowth, we explored the effectiveness of using a prosthesis with a metaphyseal taper from the anatomic neck to the diaphysis. This component is designed to obtain press-fit fixation in the cancellous bone of the metaphysis rather than in the cortical bone of the diaphysis. We tested the hypothesis that this press-fit humeral stem, designed to respect the taper of the proximal part of the humeral canal, would be associated with a low rate of loosening in patients managed with primary shoulder arthroplasty for osteoarthritis. METHODS: A prospective study was conducted to evaluate the prevalence of radiolucent lines around press-fit humeral prostheses. One hundred and thirty-one patients with glenohumeral osteoarthritis were followed for a minimum of two years. A zonal method of evaluating radiolucent lines was established. Shift in position and subsidence were judged qualitatively. RESULTS: No component showed subsidence or a shift in position. Fifty shoulders (39%) had no radiolucency. Two shoulders had radiolucency around the proximal part of the prosthesis, and seventy-five had radiolucency at the distal tip. Eleven radiolucencies were > or =1 mm in width. A neutral stem orientation was significantly less likely to be associated with radiolucency (p = 0.026). The prevalence of radiolucent lines did not differ between patients managed with hemiarthroplasty and those managed with total shoulder arthroplasty, and it did not increase with longer periods of follow-up. CONCLUSIONS: In patients managed with shoulder arthroplasty, the fixation of a press-fit humeral component that has a tapered metaphyseal segment is comparable with that reported for cemented components and superior to that reported for press-fit cylindrical components. CLINICAL RELEVANCE: This type of fixation may provide an alternative to cementing of the humeral stem in individuals with glenohumeral osteoarthritis.

Adult↗
PubMed2002

Standardized analysis of UHMWPE wear particles from failed total joint arthroplasties.

Periprosthetic tissue obtained at revision surgery from eight total hip replacement cases was hydrolyzed, and polyethylene debris particles were isolated from each case. Individual particles were analyzed by scanning electron microscopy (SEM) and computerized image analysis in accordance with ASTM F1877-98, a standard for quantitative description of wear debris. For comparison, periprosthetic tissues from eight total knee revision and four total shoulder revision cases were processed and analyzed with identical methods. A total of 2599 hip, 4345 knee, and 1200 shoulder particles were analyzed. The morphologies of the isolated polyethylene particles from the total hip specimens were distinctly different from the total knee and total shoulder particles. The mean equivalent circle diameter (ECD) for hip particles was 0.694 microm +/- 0.005; knee particles measured 1.190 microm +/-0.009; and shoulder particles 1.183 microm +/- 0.017. The ECD was significantly different between hip particles and those from the shoulder and knee. The mean aspect ratio (AR) for the hip particles was 1.626 +/- 0.015, compared to the knee particles at 1.935 +/- 0.015 and shoulder particles at 2.082 +/- 0.033. The AR was statistically different among all three groups. Other descriptors from the ASTM standard, elongation (E), form factor (FF), and roundness (R) were all significantly different among the three groups of joints. This study demonstrates the utility of ASTM F1877-98 in differentiating wear debris particles from different sources.

Adult↗
PubMedDate not supplied

A prospective functional outcome study of shoulder arthroplasty for osteoarthritis with an intact rotator cuff.

Prospective pain relief and functional outcome data were obtained on 65 shoulder arthroplasties in 55 patients. Thirty-seven total shoulder arthroplasties (TSAs) and twenty-eight hemiarthroplasties were followed up for a mean of 4.3 years (range, 2-8 years). The mean age was 63 years. Pain scores on a visual analog scale improved from a preoperative mean of 64 to 12 postoperatively. TSA and hemiarthroplasty postoperative scores did not differ significantly, but TSA patients started with a worse preoperative score and improved more. Five other visual analog scale scores improved, including function and quality of life. There were similar relationships between TSAs and hemiarthroplasties in each instance (poorer preoperative scores and more improvement). The American Shoulder and Elbow Surgeons Shoulder Score Index improved from 39 to 88 with surgery. The hemiarthroplasty group improved from a mean of 42 to 84, and the TSA group improved from 37 to 91. Although the numerical differences were small, the superiority of TSAs with regard to final score and rate of improvement was statistically significant. Patients with the poorest preoperative scores improved the most, regardless of prosthesis type. Mean active forward elevation improved from 100 degrees to 147 degrees, external rotation improved from a mean of 7 degrees to 39 degrees, and internal rotation improved by a mean of 3 spinal segments. These measures did not differ between TSA and hemiarthroplasty patients. One implant failure was treated with revision from TSA to hemiarthroplasty. Radiographic parameters characterizing component position and offset were measured, but none was found to predict outcome. The results suggest a modest superiority of TSA over hemiarthroplasty in the medium term. Because both TSA and hemiarthroplasty provide considerable and nearly comparable improvement, the long-term risks of glenoid wear and loosening need to be clearly defined before a definitive conclusion can be reached regarding the differential indications for these two procedures.

Aged↗
PubMedDate not supplied

Observation on retrieved Hylamer glenoids in shoulder arthroplasty: problems associated with sterilization by gamma irradiation in air.

Hylamer is an ultra-high molecular weight polyethylene that was used in the glenoid prosthesis of the Global Shoulder. It was developed from a joint venture with DePuy Orthopaedics, Inc, and E.I. DuPont Company. In presterilization evaluations it was noted to have improved mechanical strength with superior creep and wear resistance. However, after sterilization was performed with gamma irradiation in an air environment from 1990 to 1993, the Hylamer glenoids were affected by oxidation, which altered the mechanical properties, and they became brittle and eroded. From 1993 to 1995 Hylamer glenoids were sterilized by gamma irradiation in a nitrogen environment. From 1995 to 1998 sterilization was by gas plasma processes, which do not create the oxidation problem. Since 1998 the glenoid prosthesis of the Global Shoulder has been made exclusively of Enduron and is gas sterilized. The primary purpose of this article is to provide orthopaedic surgeons the best information available about Hylamer glenoids. We make suggestions concerning the diagnosis and treatment of the patients who had a Hylamer glenoid inserted between 1990 and 1993.

Arthroplasty, Replacement↗