Abstract
To determine if the surface area of partial thickness (< 50%), Bursal side tears of the cuff influence outcome following Subacromial Decompression.
Shoulder function using Constant score (CS) was recorded before and a minimum of one year after Arthroscopic Subacromial Decompression (ASD) in patients undergoing surgery for primary impingement. In patients who had partial thickness, Bursal side tears (BT), the length of the tear in its largest dimension (surface area) was measured. These patients were divided into two groups according to the tear surface area (≤9 mm and ≥10mm) .To determine whether having a BT (< 50% thickness) or its surface area affect pre and postoperative CS, t-tests were performed.
110 patients underwent ASD over a one-year period for primary impingement. 22 patients with partial thickness BT and18 patients with intact rotator cuff were included in this study. In 10 patients, the BTwas ≤9 mm (mean7mm) and in 12 patients BTwas ≥10mm(mean13mm). Statistical analysis of Pre-& postoperative Constant scores showed that, in ≤9 mm group CS increased significantly by 21.5, p=0.02, 95% CI (4.9, 38.1). CS increased in ≥10mm group by 22.8, p< 0.01, 95%(11.5, 34.1). Comparing the change in CS between these two groups with different tears size, there was no significant difference (2-sample t-test, t=0.15, 20df, p=0.88).
To determine whether having BT tear affects pre- and post-operative Constant scores, all BTs were grouped together and compared with the group of patients with intact cuff.
In the group with BTs, average Constant scores increased significantly (paired t-test,t=5.24,21df,p< 0.01) by 22.2 with 95% CI (13.4, 31.0). In the group with no tears, average Constant scores increased significantly (paired t-test,t=5.17,17df,p< 0.01) by 26.6, 95% CI (15.8, 37.5).
Comparing the levels of absolute change in Constant scores from pre- to post-operation between the two groups there is no difference in outcome between patients with a tear and those without a tear (2-sample t-test, t=1.03, 38df, p=0.31).
We conclude that ASD yields satisfactory results in patients with BTs involving < 50% thickness, irrespective of the surface area of the tear.
These abstracts were prepared by Mr Cormac Kelly. Correspondence should be addressed to him c/o British Orthopaedic Association, Royal College of Surgeons, 35-43 Lincoln’s Inn Fields, London WC2A 3PN.
