Subacromial Injections for Shoulder Subacromial Pain Syndrome - Comparing Anterolateral Versus Posterior Approach: A Randomised Controlled Trial

Patients who present with subacromial pain syndrome (disorders such as subacromial bursitis, rotator cuff tendinopathy, calcific tendinitis, subacromial inflammation with a partial thickness rotator cuff tear) to the orthopaedic outpatient clinic are treated initially with a subacromial steroid injection in addition to physiotherapy for a period of 3 months. This applies to patients who have had no other treatments previously as well as to patients who have had previous physiotherapy or steroid injections prior to presentation. Patients who do not want to undergo the treatment offered are either treated with simple analgesia, sole physiotherapy or surgery.

When a patient with one of the above conditions agrees to go ahead with a steroid injection followed by physiotherapy, the steroid injection is given at the earliest opportunity. The steroid injection is given into the subacromial space either using the anterolateral (front-side) approach (1 cm below and behind the anterior edge of the acromion with the needle aiming towards the under surface of the acromion) or using the posterior (back-side) approach ( 1cm inferior and medial to the posterlateral acromial edge with the needle pointing towards the anterolateral aspect of the acromion). The exact approach is determined according to the preference of the person carrying out the injection. As a routine we use a 10ml syringe containing 10mls of 0.25% Marcaine along with 40mg triamcinolone with an 18 gauge (green) needle. It is normal for patients to complain of some discomfort during the injection. If a patient experiences any significant discomfort or they cannot tolerate the injection for whatever reason, then the injection is discontinued and is not reattempted using a different approach.

Following the injection, patients are questioned on any discomfort experienced during the injection and on whether or not their pain has improved. They are then taken through a protocol of physiotherapy for their shoulder over the subsequent 3 months. A protocol is issued for guidance however therapists are allowed to use other modalities as per their discretion. The frequency of appointments with physiotherapy will depend on patient's symptoms as well as their progression. For study purposes a frequency record of these meetings will be kept and matched to the overall OSS. Patients are seen routinely in 3 months following an injection in order to assess any improvement in symptomatology using the OSS, visual analogue score, DASH and SF36 questionaires. If the symptoms have improved then no further intervention is taken. Further OSS, visual analogue pain score, DASH and SF36 questionaires will be posted out at 6 months and 1 year. On the other hand, if they are still troubled with symptoms then the possibility of further injections or surgery is discussed.

The aim of this study is to compare the two approaches that are currently used for subacromial steroid injections, namely the anterolateral and posterior approach, with regards to their effectiveness in improving shoulder symptoms. There will be no deviation from our routine protocol other than randomising patients who agree to participate in this study to either the anterolateral or posterior approach.

In summary, it is patients who are seen in clinic with a subacromial pathology and subsequently diagnosed with shoulder subacromial pain syndrome, who are offered an injection. Those who agree to have an injection will then be invited to participate in the study. An information leaflet will be given to all potential participants and they will be allowed sufficient time to read through it, digest all the information and ask any questions they may have before making a decision regarding their participation. Those who agree to participate will be randomly allocated, using sealed envelopes to one of the two approaches for the injection. The injection will then be administered via the selected approach by a clinician who is qualified in carrying out the procedure. Patients will be asked about any discomfort experienced during the injection, improvement in pain following the injection prior to leaving hospital and overall satisfaction with the injection. Following this patients will have physiotherapy as an outpatient as routine and will be seen at about 3 months post injection for a further assessment at the clinic. Again the shoulder assessment will be repeated on that occasion. Shoulder assessment questionaires will be posted out for completion at 6 months and 1 year (OSS, pain on visial analogue scale, DASH and SF36) There will be no change in patients care from routine practice other than the randomisation of the approach used for the injection. Patients who are invited to participate in the study and agree to participate will have their GP informed of their participation.