Outcome following Bankart repair for shoulder instability 1998-2002 using a subjective patient based shoulder questionnaire (Oxford)

Evaluation of Oxford instability shoulder score, Western Ontario shoulder instability index and Euroqol in patients with SLAP (superior labral anterior posterior) lesions or recurrent anterior dislocations of the shoulder

Background

Having an estimate of the measurement error of self-report questionnaires is important both for assessing follow-up results after treatment and when planning intervention studies. Specific questionnaires have been evaluated for patients with shoulder instability, but not in particular for patients with SLAP (superior labral anterior posterior) lesions or recurrent dislocations. The aim of this study was to evaluate the agreement, reliability, and validity of two commonly questionnaires developed for patients with shoulder instability and a generic questionnaire in patients with SLAP lesions or recurrent anterior shoulder dislocations.

Methods

Seventy-one patients were included, 33 had recurrent anterior dislocations and 38 had a SLAP lesion. The patients filled in the questionnaires twice at the same time of the day (± 2 hours) with a one week interval between administrations. We tested the Oxford Instability Shoulder Score (OISS) (range 12 to 60), the Western Ontario Shoulder Instability Index (WOSI) (0 to 2100), and the EuroQol: EQ-5D (−0.5 to 1.0) and EQ-VAS (0 to 100). Hypotheses were defined to test validity.

Results

ICC ranged from 0.89 (95% CI 0.83 to 0.93) to 0.92 (0.87 to 0.95) for OISS, WOSI, and EQ-VAS and was 0.66 (0.50 to 0.77) for EQ-5D. The limits of agreement for the scores were: -7.8 to 8.4 for OISS; -339.9 to 344.8 for WOSI; -0.4 to 0.4 for EQ-5D; and −17.2 and 16.2 for EQ-VAS. All questionnaires reflect the construct that was measured. The correlation between WOSI and OISS was 0.73 and ranged from 0.49 to 0.54 between the shoulder questionnaires and the generic questionnaires. The divergent validity was acceptable, convergent validity failed, and known group validity was acceptable only for OISS.

Conclusion

Measurement errors and limitations in validity should be considered when change scores of OISS and WOSI are interpreted in patients with SLAP lesions or recurrent shoulder dislocations. EQ-5D is not recommended as a single outcome.

Long-term results after arthroscopic shoulder stabilization using suture anchors: an 8- to 10-year follow-up

BACKGROUND

Arthroscopic stabilization using suture anchors is widely used to restore stability after anterior shoulder dislocations and is associated with low recurrence rates in short-term follow-up studies.

PURPOSE

To evaluate the long-term follow-up after arthroscopic stabilization for traumatic recurrent anterior instability using suture anchors with emphasis on both redislocations and subjective shoulder function.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

We included 67 consecutive patients with 70 affected shoulders. After 8 to 10 years, patients were asked to report the presence and course of their redislocations. Subjective shoulder function was addressed using the Oxford Instability Score (OIS), the Western Ontario Shoulder Instability Index (WOSI), and the Simple Shoulder Test (SST). Patients rated their health status using the Short Form-36 (SF-36).

RESULTS

Sixty-five patients with 68 affected shoulders (97%) were evaluated for follow-up; 35% reported a redislocation. Median shoulder function scores were 16 of 12 to 60, 22 of 0 to 210, and 12 of 0 to 12 for the OIS, WOSI, and SST, respectively. There was a significant difference in subjective function between patients with and without recurrent instability, respectively, 16 versus 24 for the OIS (P = .004), and 16 versus 47 for the WOSI (P = .05). We found a trend for an inverse relationship between the number of suture anchors and recurrent instability, with 2 having a higher recurrence rate than 3 or more (P = .06). Another trend was found with the presence of a Hill-Sachs defect slightly increasing the risk of a redislocation (P = .07).

CONCLUSION

With a follow-up of 97%, about one third of the stabilized shoulders experienced at least one redislocation after 8 to 10 years. The presence of a Hill-Sachs defect and the use of less than 3 suture anchors might increase the chance of a redislocation. Patients without a redislocation have a significantly better shoulder function compared with patients with a redislocation.

Comparison of two patient-based outcome measures for shoulder instability after nonoperative treatment

This study compared the responsiveness and minimal clinically important differences of the Oxford Instability Shoulder Score (OISS) and Shoulder Rating Questionnaire (SRQ). Ninety-three patients referred to physiotherapy with shoulder instability (100 shoulders) completed the questionnaires at the initial appointment and at 1 and 9 months later. A subjective rating of change was also obtained. Both questionnaires were able to detect change (effect sizes 1.16 OISS and 0.99 SRQ). The OISS change scores correlated more consistently with patients' subjective responses. The minimal detectable change (MDC90) scores were 16% (7 points) for the OISS and 17% (8 unweighted points) for the SRQ. The minimal clinically important difference (MCID) was between 9%, 4.5 points ("slightly better" and "much better") and 13.5%, 6.5 points ("much better") for the OISS, dependent on the subjective descriptors used, and 11% (4 unweighted points) for SRQ. The MCID change scores varied in relation to the baseline level of function.