The use of patient-reported outcome measures and patient satisfaction ratings to assess outcome in hemiarthroplasty of the shoulder

J. L. Rees,
J. Dawson,
G. C. R. Hand,
C. Cooper,
A. Judge,
A. J. Price,
D. J. Beard,
A. J. Carr

From the University of Oxford, Oxford, United Kingdom

J Bone Joint Surg Br. 2010 Aug;92(8):1107-11.

We have compared the outcome of hemiarthroplasty of the shoulder in three distinct diagnostic groups, using survival analysis as used by the United Kingdom national joint registers, patient-reported outcome measures (PROMs) as recommended by Darzi in the 2008 NHS review, and transition and satisfaction questions.

A total of 72 hemiarthroplasties, 19 for primary osteoarthritis (OA) with an intact rotator cuff, 22 for OA with a torn rotator cuff, and 31 for rheumatoid arthritis (RA), were followed up for between three and eight years. All the patients survived, with no revisions or dislocations and no significant radiological evidence of loosening. The mean new Oxford shoulder score (minimum/worst 0, maximum/best 48) improved significantly for all groups (p < 0.001), in the OA group with an intact rotator cuff from 21.4 to 38.8 (effect size 2.9), in the OA group with a torn rotator cuff from 13.3 to 27.2 (effect size 2.1) and in the RA group from 13.7 to 28.0 (effect size 3.1). By this assessment, and for the survival analysis, there was no significant difference between the groups. However, when ratings using the patient satisfaction questions were analysed, eight (29.6%) of the RA group were ‘disappointed’, compared with one (9.1%) of the OA group with cuff intact and one (7.7%) of the OA group with cuff torn. All patients in the OA group with cuff torn indicated that they would undergo the operation again, compared to ten (90.9%) in the OA group with cuff intact and 20 (76.9%) in the RA group.

The use of revision rates alone does not fully represent outcome after hemiarthroplasty of the shoulder. Data from PROMs provides more information about change in pain and the ability to undertake activities and perform tasks. The additional use of satisfaction ratings shows that both the rates of revision surgery and PROMs need careful interpretation in the context of patient expectations.

Degenerative changes in joints represent a significant health burden worldwide, and their prevalence is expected to rise.1-4 This will increase the demand for arthroplasty.5-8 Most developed countries have national joint registers monitoring the outcome of joint replacements. The results, generally presented as revision rates or formal survival analyses, represent outcomes and performance based on the use of revision as the endpoint. Although pain may be an indication for revision, Murray and Frost,9 in 1998 showed that when pain, instead of revision, was used as an endpoint in survival analysis, the success of total knee replacement dropped from 97.5% to 72%. This demonstrates that lack of revision alone does not necessarily mean the continued ‘success’ of an operation or an implant.

Besides using revision as an assessment of outcome, clinician-based scores have remained the most popular adjunct to survival analysis. However, these are prone to observer bias.10 Orthopaedic surgery has started to follow the non-surgical specialties by developing and using outcome assessments that are completed by patients. The use of these validated patientreported outcome measures (PROMs) has, however, remained limited, despite the availability of a number of suitable scores with satisfactory measurement properties.11-14 PROMs are intended to assess outcome from the patient’s perspective and can vary in their specificity. Some are generic (such as the Short- Form 36 (SF-36)15), whereas others are disease-specific, such as the Arthritis Impact Measurement Scales,16 and limb-specific, such as the Disabilities of the Arm, Shoulder and Hand (DASH).12 The Oxford scores (hip, knee, shoulder and elbow) were devised with the help of patients who were about to undergo surgery. They were designed as joint-specific PROMs and validated in the context of surgery. They represent the perspective of the patient rather than of the clinician. Their importance in elective orthopaedics has recently been highlighted by a review from the United Kingdom Department of Health.17 The Oxford scores have been used since April 2009 to assess the outcome of hip and knee replacements in the United Kingdom,18-20 and assessment of other joint replacements, such as the shoulder, using PROMs will shortly be introduced. PROMs have also been chosen for this role because they are postal questionnaire scores with high return rates and are therefore more costeffective than calling patients back for assessment.