Assessing activity in joint replacement patients.
TL;DR: This study indicates that both the UCLA activity rating and the investigator visual analog scale are valid for routine activity assessment in a clinical setting.
Abstract: Outcome evaluations of lower extremity joint reconstructions should include an assessment of patient activity. In vivo wear assessments of total joint prostheses should be based on a measure of use, not time in situ or a proxy such as age or gender; however, clinicians lack a simple method to reliably assess the activity of patients with joint replacement. The modern pedometer can be a satisfactory means of quantifying the use of lower extremity joints. The pedometer, however, requires special effort on the part of the physician or evaluator and the patient. Therefore, we compared the quantitative assessment of walking activity of 100 total joint replacement patients, as measured with a pedometer, to the UCLA activity score and a simple visual analog scale that can easily be employed during a routine office evaluation. Both the UCLA activity rating (P = .002) and the visual analog scale rating of the investigator (P = .00001) had a strong correlation with the average steps per day as recorded by the pedometer. There was, however, up to a 15-fold difference in the average steps per day for individual patients with the same UCLA score. The visual analog scale as rated by the patients of their own activity did not have as strong a correlation with the pedometer data (P = .08) as did patient age (P = .049). For practical reasons, the pedometer is probably best reserved for the evaluation of extreme cases of activity (or inactivity). This study indicates that both the UCLA activity rating and the investigator visual analog scale are valid for routine activity assessment in a clinical setting. Adjustments of the UCLA activity score for the frequency and intensity of activity, as can be done with the investigator visual analog scale, increase the accuracy of the activity rating.
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TL;DR: Surgeons must consider implant design, expected component size and acetabular component positioning in order to reduce early failures when performing large-bearing metal-on-metal hip resurfacing and replacement.
Abstract: Early failure associated with adverse reactions to metal debris is an emerging problem after hip resurfacing but the exact mechanism is unclear. We analysed our entire series of 660 metal-on-metal resurfacings (Articular Surface Replacement (ASR) and Birmingham Hip Resurfacing (BHR)) and large-bearing ASR total hip replacements, to establish associations with metal debris-related failures. Clinical and radiological outcomes, metal ion levels, explant studies and lymphocyte transformation tests were performed. A total of 17 patients (3.4%) were identified (all ASR bearings) with adverse reactions to metal debris, for which revision was required. This group had significantly smaller components, significantly higher acetabular component anteversion, and significantly higher whole concentrations of blood and joint chromium and cobalt ions than asymptomatic patients did (all p < 0.001). Post-revision lymphocyte transformation tests on this group showed no reactivity to chromium or cobalt ions. Explants from these revisions had greater surface wear than retrievals for uncomplicated fractures. The absence of adverse reactions to metal debris in patients with well-positioned implants usually implies high component wear. Surgeons must consider implant design, expected component size and acetabular component positioning in order to reduce early failures when performing large-bearing metal-on-metal hip resurfacing and replacement.
726 citations
TL;DR: The accumulated evidence herein provides ample support that the simple and inexpensive pedometer is a valid option for assessing physical activity in research and practice.
Abstract: Valid assessment of physical activity is important to researchers and practitioners interested in surveillance, screening, programme evaluation and intervention. The validity of an assessment instrument is commonly considered its most important attribute. Convergent validity is the extent to which an instrument’s output is associated with that of other instruments intended to measure the same exposure of interest. A systematic review of the literature produced 25 articles directly relevant to the question of convergent validity of pedometers against accelerometers, observation, and self-reported measures of physical activity. Reported correlations were pooled and a median r-value was computed. Pedometers correlate strongly (median r = 0.86) with different accelerometers (specifically uniaxial accelerometers) depending on the specific instruments used, monitoring frame and conditions implemented, and the manner in which the outputs are expressed. Pedometers also correlate strongly (median r = 0.82) with time in observed activity. Time in observed inactivity correlated negatively with pedometer outputs (median r = -0.44). The relationship with observed steps taken depended upon monitoring conditions and speed of walking. The highest agreement was apparent during ambulatory activity (running, walking) or during sitting (when both observation and pedometers would register few steps taken). There was consistent evidence of reduced accuracy during slow walking. Pedometers correlate moderately with different measures of energy expenditure (median r = 0.68). The relationship between pedometer outputs and energy expenditure is complicated by the use of many different direct and indirect measures of energy expenditure and population samples. Concordance with self-reported physical activity (median r = 0.33) varied depending upon the self-report instrument used, individuals assessed, and how pedometer outputs are expressed (e.g. steps, distance travelled, energy expenditure). Pedometer output has an inverse relationship with reported time spent sitting (r = -0.38). The accumulated evidence herein provides ample support that the simple and inexpensive pedometer is a valid option for assessing physical activity in research and practice.
634 citations
TL;DR: Steeply-inclined acetabular components, with abduction angles greater than 55 degrees, combined with a small size of component are likely to give rise to higher serum levels of cobalt and chromium ions, probably due to a greater risk of edge-loading.
Abstract: We examined the relationships between the serum levels of chromium and cobalt ions and the inclination angle of the acetabular component and the level of activity in 214 patients implanted with a metal-on-metal resurfacing hip replacement. Each patient had a single resurfacing and no other metal in their body. All serum measurements were performed at a minimum of one year after operation. The inclination of the acetabular component was considered to be steep if the abduction angle was greater than 55°.
There were significantly higher levels of metal ions in patients with steeply-inclined components (p = 0.002 for chromium, p = 0.003 for cobalt), but no correlation was found between the level of activity and the concentration of metal ions. A highly significant (p < 0.001) correlation with the arc of cover was found. Arcs of cover of less than 10 mm were correlated with a greater risk of high concentrations of serum metal ions. The arc of coverage was also related to the design of the component and to size as well as to the abduction angle of the acetabular component. Steeply-inclined acetabular components, with abduction angles greater than 55°, combined with a small size of component are likely to give rise to higher serum levels of cobalt and chromium ions. This is probably due to a greater risk of edge-loading.
536 citations
TL;DR: In this paper, the average volumetric wear rate per million cycles with a 70 kg patient weight was 30 mm 3, which can be considered a target wear rate for standard polyethylene in hip simulator studies.
Abstract: Polyethylene wear (linear penetration) in 37 hip replacements was assessed from digital images using a validated two-dimensional, edge detection-based computer algorithm. Patient activity was assessed with a pedometer, a step activity monitor and a simple visual analog scale. Joint use was related to wear at the 90% confidence level. Without three recognized outliers, wear was highly correlated to use. The visual analog scale activity rating was significantly related to wear for the 24 hip replacements with standard polyethylene. Univariate regression analysis indicated that male gender, height, weight (which were both highly correlated to male gender) and hip center of rotation were significantly correlated to wear. Multivariate regression analysis indicated that male gender, femoral off-set, and Hylamer® were significantly correlated to wear. Based on the wear and activity data from the 24 hip replacements with standard polyethylene, the average volumetric wear rate per million cycles with a 70 kg patient weight was 30 mm 3 . This unique in vivo result can be considered a target wear rate for standard polyethylene in hip simulator studies.
455 citations
TL;DR: The clinical history, functional status, activity status, and physical examination findings that characterize femoroacetabular impingement were determined and these data may facilitate diagnosis of this disorder.
Abstract: Femoroacetabular impingement (FAI) is considered a cause of labrochondral disease and secondary osteoarthritis. Nevertheless, the clinical syndrome associated with FAI is not fully characterized. We determined the clinical history, functional status, activity status, and physical examination findings that characterize FAI. We prospectively evaluated 51 patients (52 hips) with symptomatic FAI. Evaluation of the clinical history, physical exam, and previous treatments was performed. Patients completed demographic and validated hip questionnaires (Baecke et al., SF-12, Modified Harris hip, and UCLA activity score). The average patient age was 35 years and 57% were male. Symptom onset was commonly insidious (65%) and activity-related. Pain occurred predominantly in the groin (83%). The mean time from symptom onset to definitive diagnosis was 3.1 years. Patients were evaluated by an average 4.2 healthcare providers prior to diagnosis and inaccurate diagnoses were common. Thirteen percent had unsuccessful surgery at another anatomic site. On exam, 88% of the hips were painful with the anterior impingement test. Hip flexion and internal rotation in flexion were limited to an average 97° and 9°, respectively. The patients were relatively active, yet demonstrated restrictions of function and overall health. These data may facilitate diagnosis of this disorder.
414 citations
Additional excerpts
...Twenty-nine percent of patients characterized their activity level as high as assessed by UCLA activity score....
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...Patients completed demographic and validated hip questionnaires (Baecke et al., SF-12, Modified Harris hip, and UCLA activity score)....
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...[1] and UCLA [32] scores) were obtained....
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...Additionally, standard measures of hip function (modified Harris hip score) [5, 12], overall health (SF-12) [31], and activity (Baecke et al. [1] and UCLA [32] scores) were obtained....
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...The average UCLA activity score was 7.1 ± 2.8 (range, 2–10), consistent with patients participating in activities like fast walking, golfing, and bowling....
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References
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TL;DR: In this article, an end-result analysis is presented of thirty-nine mold arthroplasties performed at the Massachusetts General Hospital between 1945 and 1965 in thirty-eight consecutive private patients for arthritis of the hip following fractures of the acetabulum or dislocations.
Abstract: An end-result analysis is presented of thirty-nine mold arthroplasties performed at the Massachusetts General Hospital between 1945 and 1965 in thirty-eight consecutive private patients for arthritis of the hip following fractures of the acetabulum or dislocations of the hip.
Of the nineteen unilateral cases in the second half of the series, sixteen were rated good or excellent. Results in the second half of the series were significantly better statistically than those in the first half of the series. Possible reasons for this improvement are discussed.
No significant deterioration occurred with the passage of time. Among the thirty-nine hips, three revisions were required. One patient had postoperative sepsis after arthroplasty. Four patients who had had intra-articular sepsis prior to arthroplasty showed no evidence of sepsis postoperatively.
Factors influencing the choice between hip fusion and hip arthroplasty in these cases are presented.
A new system for rating hip function is proposed and is compared with the systems of Larson and Shepherd.
5,665 citations
TL;DR: A new total knee rating system has been developed by The Knee Society to provide an up-to-date more stringent evaluation form and eliminates the problem of declining knee scores associated with patient infirmity.
Abstract: A new total knee rating system has been developed by The Knee Society to provide an up-to-date more stringent evaluation form. The system is subdivided into a knee score that rates only the knee joint itself and a functional score that rates the patient's ability to walk and climb stairs. The dual rating system eliminates the problem of declining knee scores associated with patient infirmity.
4,505 citations
643 citations
TL;DR: Multivariate stepwise regression analysis showed that the factors that affected the final extent and width of the acetabular radiolucencies adversely after resurfacing were: any radiolucent lines that were visible at six months, a high level of physical activity after arthroplasty, and a thin superior cement mantle.
Abstract: Of 285 total hip arthroplasties (260 patients) performed for primary osteoarthritis during a six-year period, 135 were resurfaced using a Tharies prosthesis (total hip articular replacement with internal eccentric shells) and 150 were treated with the Trapezoidal-28 total hip replacement. From each of these two groups 100 hips (ninety-one patients in the Tharies group and eighty-six in the Trapezoidal-28 group) that had been followed for two to seven years were evaluated at the time of follow-up in accordance with a predetermined protocol. The patients were younger in the Tharies than in the Trapezoidal-28 group (average ages, fifty-eight and sixty-six years), included more men (sixty compared with thirty-five), and were more active postoperatively. The average follow-up was forty-seven months for the total joint-replacement group and thirty-eight months for the surface replacement group. At follow-up the ratings for pain, walking, and function according to the University of California at Los Angeles 10-point scale and the clinical results were identical in the two groups. Heterotopic ossification (Brooker grade III or IV) developed after thirteen Trapezoidal-28 and twenty-two Tharies arthroplasties. Radiographs made at six and twelve months and at final follow-up showed that the incidence of radiolucencies about the acetabular component was higher in the resurfacing group: fifty-seven with complete radiolucent lines after an average follow-up of thirty-eight months compared with thirty-six with complete lines after an average follow-up of forty-seven months. There were three failures in the joint-replacement group: a hematogenous staphylococcal deep infection that required a Girdlestone procedure, a femoral stem fracture that required revision, and loosening of an acetabular component for which revision was performed. There was also one dislocation, successfully treated by closed reduction. Similarly, in the resurfacing group there were three failures: two loose acetabular components, revised successfully, and one loose femoral component that necessitated total joint arthroplasty. Multivariate stepwise regression analysis showed that the factors that affected the final extent and width of the acetabular radiolucencies adversely after resurfacing were: any radiolucent lines that were visible at six months, a high level of physical activity after arthroplasty, and a thin superior cement mantle.(ABSTRACT TRUNCATED AT 400 WORDS)
597 citations