Can Shoulder Arthroscopy Work
Condition: Shoulder Impingement Syndrome
MeSH terms: Shoulder Impingement Syndrome
Study type: Interventional

Summary: 
      Shoulder problems causing pain and decreased function are very common. Many of these problems
      are related to the rotator cuff tendons. Shoulder arthroscopy surgery (keyhole surgery) is a
      common treatment for this pain. This can involve an Arthroscopic Subacromial Decompression
      (ASAD) an operation used to remove bony spurs which may be the cause of the pain. This
      procedure is widely used despite limited evidence of any effectiveness. This is a randomised
      controlled trial that will compare ASAD against an investigational shoulder arthroscopy
      (without spur removal/decompression) to indicate whether spur removal is really necessary and
      in turn, assessing the effectiveness of the ASAD procedure. Both surgical interventions are
      routine and will mirror each other except for the spur removal element. Both treatments will
      be compared against a control (non operative management with specialist reassessment) group
      to indicate whether surgery in general is effective for patients with subacromial pain.
      Patients randomised to either of the surgical options will be blinded to the type of surgery
      they have. This is a multicentre trial taking place in 10 centres in England and Wales. Two
      satellite studies will also take place. One will involve a subset of patients undergoing MRI
      scans to examine the effects of their shoulder pain on their brain transmissions. The other
      will involve collecting tissue samples from patients undergoing surgery.
    

Detailed description: 
      The prevalence of shoulder complaints in the UK is estimated to be 14%, with 1-2% of adults
      consulting their general practitioner annually regarding new-onset shoulder pain. Rotator
      cuff pathology, including rotator cuff tears and sub-acromial pain, reportedly accounts for
      up to 70% of shoulder pain problems. Other common causes of shoulder pain include frozen
      shoulder, calcific tendonitis and osteoarthritis (OA).

      Painful shoulders pose a substantial socioeconomic burden. Disability of the shoulder can
      impair ability to work or perform household tasks and can result in time off work. Shoulder
      problems account for 2.4% of all general practitioner consultations in the UK and 4.5 million
      visits to physicians annually in the USA. With the exception of fractures and traumatic
      rotator cuff tears, most shoulder pain problems are treated initially with conservative care.
      In some patients with persistent symptoms, surgery might be required. More than 300,000
      surgical repairs for rotator cuff pathologies are performed annually in the USA, and the
      annual financial burden of shoulder pain management in the USA has been estimated to be US$3
      billion.

      Sub-acromial pain is the most frequent cause of shoulder problems in the general population.
      An anatomical etiology has been proposed, whereby mechanical contact occurs between the
      rotator cuff tendons and the overlying acromion and coracohumeral ligament. Sub-acromial pain
      and rotator cuff tears are associated with progressive change in the shape of the acromion,
      with 'spurs' forming at its antero-inferior margin. Evidence suggests spurs develop which
      narrow the sub-acromial space, thereby making physical contact more likely, particularly in
      certain positions of the arm (for example, painful arc), and resulting in inflammation. This
      is sometimes referred to as "impingement". However this term suggests a definitive mechanism
      of the pain and conflicting theories indicate such mechanisms are not definitive. For the
      purposes of this study we will continue to refer to this as "sub-acromial pain".

      A high proportion of patients with sub-acromial pain will respond to conservative treatment.
      The most frequent indications for surgery are persistent and severe pain combined with
      functional restrictions that are resistant to conservative measures. Despite surgery being
      considered at this point, some reports show that surgery can be no more effective than
      physiotherapy in the relief of pain when used in patients at this stage. Surgical
      intervention can, however, achieve good results and its judicious use seems valid. The most
      common surgical intervention for sub-acromial pain is a sub-acromial decompression (SAD),
      which can be performed through an arthroscopic (ASAD) approach. An assessment of the cost of
      treatment of impingement also suggested that the addition of surgery, in comparison to
      exercise treatment alone, is not cost-effective.

      Further research might identify whether the source of pain is the tendon, the acromion or the
      bursa, and hence help to rationalize surgical treatment.

      One possible sequela of sub-acromial pain is a rotator cuff tear. The term 'rotator cuff
      tear' refers to structural failure and tissue disruption in at least one of the four muscles
      and tendons that form the rotator cuff. Any tear that involves rotator cuff disruption that
      does not extend all the way through the tendon is termed a partial-thickness tear (PTT). PTTs
      are more prevalent than full-thickness tears. Information is lacking regarding the risk of
      progression of PTTs to full-thickness tears although it is thought that lesions involving
      less than 50% of the thickness of the cuff are at risk of progression in the long term as
      shown by Cordasco et al. The management of PTTs is controversial and patients with PTTs have
      commonly been treated conservatively. If the symptoms fail to resolve with conservative
      treatment then ASAD might be beneficial. Favourable results have been reported following
      debridement of PTT in association with ASAD.

      It is largely assumed that arthroscopic sub-acromial decompression (ASAD) has some
      therapeutic benefit. This is on the assumption that much of the pain and symptoms of
      sub-acromial pain is due to mechanical contact between the upper surface of the rotator cuff
      tendons and the under-surface of the acromion. This pain is also believed to be associated
      with inflammation of the intervening sub-acromial bursa.

      ASAD has been performed for the treatment of sub-acromial pain and rotator cuff disease for
      the last 35 years. The number of ASADs performed by orthopaedic surgeons has increased
      significantly over time. A fact made remarkable by the absence of any compelling or concrete
      evidence in support of the procedure. Recent figures from the USA report a 254% increase
      (from 29.9 to 102.2 per 100 000 people per year) in use of the procedure in New York State
      between 1996 and 2006 with only a 74% increase in orthopaedic surgery overall and a 475%
      increase (from 3.3 to 19.0 per 100 000 people per year) in use of the procedure in Olmsted
      County, Minnesota in the 25 years leading up to 2005. Although both studies show a
      significant increase in use of the procedure, the New York State surgeons perform over five
      times as many decompressions as their colleagues in Rochester Minnesota. The introduction of
      less invasive arthroscopic techniques accounts for some of the overall increased rate of
      surgery but does not explain the geographical variation. Patient and disease characteristics
      have not changed over time and there is a growing concern that this procedure is being
      overused. Observational studies of ASAD show positive results in terms of pain reduction and
      functional outcome with high patient satisfaction rates. However, equally good outcomes have
      been noted in two studies following patients who had arthroscopic rotator cuff debridement or
      open rotator cuff repair in the absence of a sub-acromial decompression. Furthermore,
      comparative studies of ASAD versus non-operative treatment options, such as physiotherapy,
      have not shown any significant difference in outcome between the two treatment modalities.

      There are a growing number of studies that have tried to assess the effectiveness of
      sub-acromial decompression against a control. Two studies randomised patients undergoing
      rotator cuff repair to groups including or excluding sub-acromial decompression in their
      operative treatment, neither demonstrated any difference in outcome between the groups. In an
      important recently reported randomised controlled trial, ASAD plus sub-acromial bursectomy
      was compared with bursectomy alone and reported no significant difference in clinical outcome
      between the two groups. This finding suggests that removing acromial spurs might not be
      necessary.

      These studies support the theory that undergoing a surgical intervention for sub-acromial
      pain carries a significant placebo effect and that removal of the sub-acromial spur of bone
      may not be necessary.

      Unfortunately no randomised trials have been performed on patients with sub-acromial pain to
      show that ASAD is more effective than simply inserting the arthroscope, as per investigative
      arthroscopy, or doing nothing at all (no treatment). The NHS Database of Uncertainties about
      the Effects of Treatment (DUETs) confirms the lack of evidence. They highlight the low level
      of evidence available and the high susceptibility of bias which exists in some of the
      publications on this topic. Therefore, we remain ignorant of the mode of action for any
      potential therapeutic effect. All three options are yet to be tested satisfactorily.

      To unequivocally state that surgery treatment is effective, the surgical procedure must be
      compared against a sham or placebo treatment. A sham surgery must be a mock up or imitation
      of the procedure. It is virtually impossible to imitate an operation without actually
      performing the surgery. In terms of placebo, there have been previous placebo controlled
      trials in surgery, particularly in the lower limb, with some interesting results. It is known
      that the very process of undergoing surgery (without necessarily affecting the structures
      involved in the pathology) can generate a beneficial outcome. This has been shown in the knee
      where a placebo controlled trial of arthroscopic surgery for osteoarthritis of the knee. This
      found that, despite early benefit, one year results after arthroscopic lavage or debridement
      were no better than after an entirely placebo operative procedure.

      Psychological mechanisms of treatments can have meaningful therapeutic effects. These may
      include expectations, memory, motivation, somatic focus, reward, anxiety reduction and
      meaning. Expectancy requires patients to have expectations of future responses to treatment.
      Arguably surgery, with all its attendant verbal and non-verbal clues, is a very powerful
      modulator of expectancy and could therefore have a profound placebo effect.

      Responses may also be conditioned and mediated through physiological changes in hormones and
      immune response. Most research into the neurobiology of placebo has investigated analgesia.
      Shoulder arthroscopy and sub-acromial decompression is principally (if not entirely) focused
      on relief of pain and patients undergoing this relatively low risk day case surgical
      procedure may well be affected by some form of placebo effect. Analgesic responses to placebo
      often involve endogenous opioid mechanisms. Other neuro-transmitters and neuromodulators may
      also be involved.

      To consider the effects of such placebo potential, the surgical procedure in question should
      have the key mechanical element(s) of the operation isolated and omitted. In this way the
      therapeutic mechanisms of the surgery can be evaluated and any perceived or non-specific
      effects of the surgery can be highlighted.
    

Intervention name(s): Arthroscopic Sub-acromial Decompression Surgery; Shoulder Arthroscopy; Active Monitoring with Specialist Reassessment
Intervention type(s): Procedure; Procedure; Other
Intervention description(s): The procedure involves insertion of the arthroscope into the glenohumeral joint where the joint surface is inspected along with the intra-articular portion of the long head of biceps and the joint surface of the rotator cuff tendons. The arthroscope is then inserted into the sub-acromial bursa which lies outside the rotator cuff tendons and beneath the acromion process of the scapula. In the bursa the acromion and superior surface of the rotator cuff are assessed to ensure the coracoacromial ligament and the AC joint remains intact. The projecting under surface of the distal part of the acromion is resected.; This is the surgical comparison group. The procedure is performed under general anaesthetic. Patients will undergo a routine investigational arthroscopy. The operation will be performed in exactly the same manner as Group ASAD. The exception is they will not undergo the decompression (bone spur removal). Tissues will be visualised and the joint will be washed out. The time spent in theatre will be similar to that for Group ASAD. These measures provide the AO group with the characteristics necessary to provide a reasonable comparison and account for the placebo effects of surgery.; Patients will be advised that they will undergo active monitoring in the short term. They will attend a reassessment appointment 3 months after entering the study. Here, they will be asked to complete questionnaires related to their shoulder pain and undergo a clinical assessment for their shoulder. From an ethical standpoint it is emphasised that it is quite within normal practice to have a period of active monitoring.
Other intervention name(s): ASAD; Arthroscopy alone; Non-operative group; Control group
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Outcomes Assessor)
Primary purpose: Treatment
Keywords: Shoulder; Sub-acromial; Rotator Cuff; Impingement