Management of Glenohumeral Arthritis.
Last updated Wednesday, January 09, 2008
Methods of assessing functional outcome
Ernest A. Codman will be remembered in the annals of orthopaedic
history as a pioneer in the study of shoulder disorders but few except
the most ardent of his followers are familiar with the role he played
as a visionary and champion of what is currently described as outcomes
research. (Codman, 1934)Evaluating success and failure Central to what Codman described in the early 1900's as an
"end-result" system was the admonition that every patient should be
followed to determine if the treatment was a success and if not to
determine the reasons for failure so that such occurrences could be
prevented in the future. Despite Codman's admonition nearly 100 years
ago, there continues to exist a lack of standardized methods for
measuring results and reporting complications associated with total
shoulder implants. Unfortunately, the lack of a universally accepted
outcome measurement system for shoulder arthroplasty increases
methodologic flaws in structured literature reviews and often precludes
meaningful retrospective or prospective comparisons between various
arthroplasty series. The desirability of research methodologies which
will improve the quality and comparability of multicenter studies is
underscored by our review of nearly fifty total shoulder replacement
series. (Boyd, Thomas, Scott, et al., 1990; Brenner, Ferlic, Clayton,
et al., 1989; Brostrom, Kronberg and Wallensten, 1992; Brumfield,
Schilz and Flinders, 1981; Clayton, Ferlic and Jeffers, 1982; Cofield
and Daly, 1992; Cofield and Stauffer, 1977; Coughlin, Morris and West,
1979; Cruess, 1980; Engelbrecht, Siegel, Rottger, et al., 1980; Faludi
and Weiland, 1983; Fenlin, 1975; Fig.gie, Inglis, Fig.gie, et al.,
1989; Frich, Moller and Sneppen, 1988; Gristina, Romano, Kammire, et
al., 1987; Gristina and Webb, 1982; Hawkins, Bell and Jallay, 1989;
Kelly, Foster and Fischer, 1987; Kolbel, Rohlmann and Bergmann, 1982;
Laurence, 1991; Lettin, Copeland and Scales, 1982; Linscheid and
Cofield, 1976; Martin, Sledge, Thomas, et al., 1995; Mazas and de la
Caffiniere, 1981; McCoy, Warren, Bade, et al., 1989; McElwain and
English, 1987; McKeeand Watson-Farrar, 1966; Neer and Morrison, 1988;
Neer and Kirby, 1982; Pahle and Kvarnes, 1985a; Pollock, Deliz,
McIlveen, et al., 1992; Post, 1987; Post, Haskell and Jablon, 1980;
Post and Jablon, 1983; Post, Jablon, Miller, et al., 1979; Roper,
Paterson and Day, 1990; Torchia, Cofield and Settergren, 1994-1995;
Warren, Ranawat and Inglis, 1982; Wilde, Borden and Brems, 1984) The
results of this review revealed that only thirty-three of these reports
assessed the outcome of treatment by applying a specific grading
system. Moreover there was a great lack of unanimity in regards to
these evaluation schemes as twenty-two different grading systems were
utilized. Also disconcerting was the variability in reported data,
variations in terminology, and ill-defined standards of assessing
complications which made it difficult to systematically analyze many of
these studies.
The necessity for improving study design, defining the important
constituents of outcome measurement, and increasing the validity of
orthopaedic clinical research has been emphasized by several authors.
(Cowell and Curtiss, 1985; Cutler and Ederer, 1958; Gartland, 1988;
Rudicel and Esdiale, 1985) It has been suggested that the current
emphasis of orthopaedic clinical studies should be directed toward
outcome research which documents the effect of treatment on the health
of those treated and the subsequent quality of their lives. (Gartland,
1988) Recently, the American Shoulder and Elbow Surgeons proposed a
standardized form for assessment of the shoulder which is applicable to
all patients regardless of diagnosis. (Richards, An, Bigliani, et al.,
1994) Such standardized forms represent assessment tools which will
facilitate the analysis of multi-center studies, permit validity
testing of measurement tools and provide documentation of patient
outcome in terms of economics and improved quality of life. Survivorship analysis The validity of survivorship analysis in the evaluation of long-term
clinical studies involving total hip replacements is well established.
(Cornell and Ranawat, 1986; Dobbs, 1980; Dorey and Amstutz, 1986;
Jinnah, Amstutz, Tooke, et al., 1986; Pavlov, 1987) Although
non-parametric estimates of survivorship based upon life tables and the
Kaplan-Meier curve have proven useful in predicting the longevity of
hip arthroplasties, the application of these instruments to total
shoulder arthroplasty studies is limited to two series. (Brenner,
Ferlic, Clayton, et al., 1989; Cofield, 1993)
In 1983, Cofield performed a non-parametric estimation of
survivorship in 176 unconstrained total shoulder arthroplasties and
predicated a 9.6 percent cumulative probability of failure at five
years. (Cofield, 1993) The criteria for failure was defined as the need
for a major reoperation which occurred in eight (4.5 percent) cases.
The indication for reoperation included early dislocation in three
shoulders, glenoid component loosening in three shoulders, and muscle
transfer for axillary nerve paralysis and resectional arthroplasty for
sepsis in one shoulder each. In a more recent article by the same
author, this Fig.ure did not significantly change at an eleven year end
point. (Torchia, Cofield and Settergren, 1994-1995) In 1989, Brenner
and colleagues (Brenner, Ferlic, Clayton, et al., 1989) analyzed the
results of fifty-three unconstrained total shoulder arthroplasties
using the Kaplan-Meier survivorship curve. Employing a more rigid
definition that considered failure as not only the need for
reoperation, but also patient dissatisfaction with the degree of pain
relief, the authors reported an eleven year survival of only 73
percent.
In a large multi-center prospective study involving more than 470
unconstrained total shoulder arthroplasties, the five year survival was
estimated at 97 percent (95 percent confidence interval). (Rockwood,
1990) A more rigid definition of failure, similar to the criteria
proposed by Brenner et al, (Brenner, Ferlic, Clayton, et al., 1989) was
applied to a subset of these patients whose diagnosis was restricted to
osteoarthritis. For these patients, failure was defined by one of two
parameters. The first parameter, as with the two previous studies,
simply involved the need for reoperation following the index procedure.
The second parameter was based upon a patient self-assessment visual
analog scale for pain. For this analysis, failure was defined as the
point in time at which the patient reported shoulder pain which was
equal or worse than the preoperative condition. For the osteoarthritis
subgroup, the probability of five year survival was 92 percent using
the more stringent criteria. Patient self-assessment As a practical approach to effectiveness measurement which can easily
be applied in an active practice, one of us (FAM) has used patient
self-assessment methods. Since January 1992, all new shoulder patients
have been asked to complete the Simple Shoulder Test (SST) (Lippitt,
Harryman and Matsen, 1993; Matsen, Lippitt, Sidles, et al., 1994) to
define their pretreatment shoulder function and the SF 36 to
characterize there overall health status. The results from these pre
treatment questionnaires serve as the baseline on "INGO" for evaluating
treatment effectiveness from the perspective of the patient. Followup
questions questionnaires reveal the "outcome" of treatment from the
patients' perspective. The difference between the outcome and the ingo
is the effectiveness of the treatment. Table 16-25 indicates some of
these early data for the effectiveness of total or hemi arthroplasty
for each of the indicated diagnoses. The preoperative scores are shown
to the left of each arrow and the followup score to the right. The data
include the SF 36 parameters for total body physical role function and
comfort as well as the 12 SST parameters which are specific to the
shoulder. The SF 36 scores are the average of the scores of the
patients. The SST scores are the percent of the patients answering yes
to the indicated question. While some of these numbers are too small
for rigorous comparison, in the future, data such as these will
indicate the absolute and relative effectiveness of different
treatments for different types of glenohumeral arthritis. Dividing the
effectiveness by the cost of treatment will reveal the cost
effectiveness for different diagnoses by different programs.Disclaimer
This resource has been provided by the University of Washington Department of Orthopaedics and Sports Medicine as general information only. This information may not apply to a specific patient. Additional information may be found at http://www.orthop.washington.edu or by contacting the UW Department of Orthopaedics and Sports Medicine.
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