The study aimed to determine if THR deep infection rate correlated with the Nosocomial Infection National Surveillance Scheme (NINSS) data on the surgical site infection (SSI) rate in our institution.

Deep infection is a serious complication of hip replacement but presents late. It has recently been reported that 10% of superficial infections develop deep prosthetic infections. NINSS data could therefore be used to predict a unit’s infection risk. This District General Hospital has only recently entered NINSS. In the first quarter of 2001, NINSS reported an 11.9% surgical site infection rate in THRS performed in this unit.

A clinical audit of all the primary THRs done between 1/4/94 – 9/9/2001, using revision surgery as the end point, was conducted to determine the true deep infection rate. Patients were identified using the OPCS coding system database and a casenote review was performed on all revision hip operations done locally. A search for our primary THRs that underwent revision surgery at the regional tertiary referral centre was completed to avoid omissions secondary to migration.

Of 1258 primary THRS, there were 13 revisions (1%) of which 2 were done for infection (0.16%).

NINSS data placed our unit on the 90th centile for infection risk but our historical true deep infection rate of 0.16% compares favourably with the Swedish and Trent hip registry rates of 0.58% and 1.4% respectively. We therefore urge careful interpretation of NINSS data and argue against its use in the media. The quarterly reporting of SSIs may be too short to play a role in ranking hospitals but may be helpful in prophylactic antibiotic selection.

Purpose: To evaluate the use of a steroid and local anaesthetic subacromial injection as a prognostic tool for patient recovery following arthroscopic subacromial decompression (ASD).

Methods: A prospective study of all patients seen in our unit with a clinical diagnosis of subacromial impingement syndrome was carried out between 1/00 and 9/01. All patients were diagnosed clinically, followed by a local anaesthetic/steroid subacromial injection test. In the event of a negative result to the injection test, the diagnosis was confirmed by CT arthrography or MRI scanning. All patients underwent standard ASD, with clinical evaluation via the Constant score preoperatively, at 3 weeks, 3 months, and at discharge. The eventual functional outcome was correlated with the results of the impingement test and the operative findings.

Results: One hundred and one patients (53 male, 48 female), with a mean age of 52 years (range 21–77) were entered into the study. Patients were followed up for a mean of 14 months (range 3–24). All patients had an impingement lesion noted at arthroscopy. The mean preoperative Constant score for the entire group was 48 (20–67) with a postoperative mean of 81 (46–98). 16 patients had a negative preoperative injection test. The mean improvement in this group was 21 points (47 rising to 68) compared to 35 points (48 to 83) in the positive group (p< 0.05, Mann-Whitney U test). The groups were otherwise similar for age, sex and operative findings.

Conclusions: The subacromial injection test is a useful tool both diagnostically and prognostically in patients with subacromial impingement syndrome. In patients with a confirmed diagnosis but a negative test there is still a significant improvement in the post operative Constant score, but this is of a lesser degree than in those with a positive injection test. This does not appear to be related to age, impingement grade or cuff tears, and may represent a true difference in the underlying pathology.