Wednesday, May 17, 2017

Is acromioplasty of value?

Does acromioplasty result in favorable clinical and  radiologic outcomes in the management of chronic  subacromial pain syndrome? A double-blinded randomized clinical trial with 9 to 14 years’ follow-up. 

These authors sought to determine the long-term clinical and radiologic treatment effect of arthroscopic acromioplasty in patients  with chronic "subacromial pain syndrome (SAPS)"  (pain located in the deltoid region for at least 3 months; inability to lie down on the affected shoulder; pain during abduction, backward flexion, or internal rotation; positive Neer or Hawkins impingement test; and positive lidocaine impingement test. In addition, conservative treatment for at least 6 weeks (ie, subacromial infiltration, nonsteroidal anti-inflammatory drugs, and supervised exercises) had to be unsuccessful. The exclusion criteria were calcifying tendinitis, biceps tendinitis, partial- or fullthickness cuff tear, labral tear, signs of glenohumeral instability, passive restriction of glenohumeral motion, osteoarthritis of the acromioclavicular or glenohumeral joint, rheumatic diseases, cervical radiculopathy, history of shoulder trauma, synovitis, and prior surgery on the affected shoulder.)

In this double-blind, randomized clinical trial, 56 patients with chronic SAPS (median age, 47 years; age range, 31-60 years) were randomly allocated to arthroscopic bursectomy alone or to bursectomy combined with acromioplasty and were followed up for a median of 12 years. 

A total of 43 patients (77%) were examined at a median of 12 years’ follow-up. Intention-to treat analysis at 12 years’ follow-up did not show a significant additional treatment effect of acromioplasty
on bursectomy alone in improvement in Constant score, Simple Shoulder Test score, VAS score for pain, or VAS score for shoulder function. 

The chart below shows the SST scores for shoulders with bursectomy alone (hollow bars) and bursectomy along with acromioplasty (solid bars).
The prevalence of rotator cuff tears was not significantly different between the bursectomy group (17%) and acromioplasty group (10%).

The authors concluded that there were no relevant additional effects of arthroscopic acromioplasty on bursectomy alone with respect to clinical outcomes and rotator cuff integrity at 12 years’ follow-up. 

Comment: While it is not clear exactly what entities are included in SAPS, this article again calls in to question the value of acromioplasty using a well-done randomized clinical trial with long term followup. 

This article should be placed in context of three other recent articles on acromioplasty discussed below.

Published Evidence Relevant to the Diagnosis of Impingement Syndrome of the Shoulder

Acromioplasty for impingement syndrome of the shoulder is one of the most common orthopaedic surgical procedures. The rate with which this procedure is performed has increased dramatically. This investigation sought high levels of evidence in the published literature related to five hypotheses pertinent to the concept of the impingement syndrome and the rationale supporting acromioplasty in its treatment.

The authors conducted a systematic review of articles relevant to the following hypotheses: (1) clinical signs and tests can reliably differentiate the so-called impingement syndrome from other conditions, (2) clinically common forms of rotator cuff abnormality are caused by contact with the coracoacromial arch, (3) contact between the coracoacromial arch and the rotator cuff does not occur in normal shoulders, (4) spurs seen on the anterior aspect of the acromion extend beyond the coracoacromial ligament and encroach on the underlying rotator cuff, and (5) successful treatment of the impingement syndrome requires surgical alteration of the acromion and/or coracoacromial arch. Three of the authors independently reviewed each article and determined the type of study, the level of evidence, and whether it supported the concept of the impingement syndrome. Articles with level-III or IV evidence were excluded from the final analysis.

These five hypotheses were not supported by high levels of evidence.

The authors concluded that the concept of impingement syndrome was originally introduced to cover the full range of rotator cuff disorders, as it was recognized that rotator cuff tendinosis, partial tears, and complete tears could not be reliably differentiated by clinical signs alone. The current availability of sonography, magnetic resonance imaging, and arthroscopy now enable these conditions to be accurately differentiated. Nonoperative and operative treatments are currently being used for the different rotator cuff abnormalities. Future clinical investigations can now focus on the indications for and the outcome of treatments for the specific rotator cuff diagnoses. It may be time to replace the nonspecific diagnosis of socalled impingement syndrome by using modern methods to differentiate tendinosis, partial tears, and complete tears of the rotator cuff.

Treatment of irreparable cuff tears with smoothing of the humeroscapular motion interface without acromioplasty

These authors sought to determine whether shoulders with irreparable rotator cuff tears and retained active elevation (>100 degrees) can be durably improved using a conservative surgical procedure that smoothes the interface between the proximal humeral convexity and the concave undersurface of the coracoacromial arch followed by immediate range of motion exercises.

The typical pathology in these cases is shown in the figure below.

The surgical approach is through a deltoid splitting incision that preserves the deltoid origin, the acromion and the coracoacromial ligament.

The coracoacromial arch is preserved to avoid the complication of anterosuperior escape that is commonly encountered when acromioplasty is performed in the presence of a large cuff tear.

The surgery includes smoothing of the prominence of the greater tuberosity that is exposed in cuff tears along with resection of adhesions in the humeroscapular motion interface and a gentle manipulation under anesthesia to resolve the stiffness that is commonly associated with chronic cuff tears. Immediate active assisted and active motion are encouraged immediately after surgery. Because no repair or reconstruction has been performed, activities, including deltoid strengthening can be resumed as soon as they are comfortable. 

They reviewed 151 patients with a mean age of 63.4 (range 40–90) years at a mean of 7.3 (range 2–19) years after this surgery. The patient data are shown below, contrasting the patients that did and did not improve by the MCID of 2 in the Simple Shoulder Test

In 77 shoulders with previously unrepaired irreparable tears, Simple Shoulder Test (SST) scores improved from an average of 4.6 (range 0–12) to 8.5 (range 1–12) (p < 0.001). Fifty-four patients (70%) improved by at least the minimally clinically important difference (MCID) of 2 SST points. 

For 74 shoulders with irreparable failed prior repairs, SST scores improved from 4.0 (range 0–11) to 7.5 (range 0–12) (p < 0.001). Fifty-four patients (73%) improved by the MCID of 2 SST points.

They provided this case example. A rancher in his mid 60s had a right rotator cuff reconstruction with freeze-dried acellular human dermal collagen tissue matrix that subsequently became infected. He presented to us with a painful stiff right shoulder. At surgery there was extensive scar throughout the humeral scapular motion interface. The subscapularis was detached but was reconstructible. The supraspinatus was absent. The upper 2/3 of the infraspinatus was absent as well. The tuberosities were prominent. He had a smooth and move procedure at which time the abundant scar in the humeral scapular motion interface was debrided. The previous sutures and Graft Jacket were excised. The bursa was removed. The prominent tuberosities were resected using a rongeur and a burr. A manipulation under anesthesia was performed to assure a full passive range of motion. Passive and active range of motion exercises were started immediately after surgery. Three years later he reported excellent shoulder comfort and function and sent us this photo of his return to one of his favorite activities

They concluded that smoothing of the humeroscapular interface can durably improve symptomatic shoulders with irreparable cuff tears and retained active elevation > 100 degrees. They point out that this conservative procedure offers an alternative to more complex procedures in the management of irreparable rotator cuff tears.

Comment: Currently surgeons are actively pursing a variety of methods for managing patients with symptomatic irreparable rotator cuff tears, including marginal convergence, patch grafts, superior capsular reconstructions, degrading subacromial 'balloons' tendon transfers and reverse shoulder arthroplasty. Each of these procedures is more complex than the smooth and move procedure described in this article and none offers the opportunity for immediate postoperative resumption of active use of the shoulder.

These results from 151 patients having the smooth and move procedure can be contrasted to those from 24 patients having a 'superior capsular reconstruction' using an 8 mm fascia lata graft harvested from the patients thigh have been reported by Mihata et al (see this link). After the superior capsular reconstruction it is recommended that an abduction pillow be used for 4 weeks after the reconstruction with active exercises not started until 8 weeks after surgery.

Of note is that standard dermal grafts that used instead of fascial lata are often <2mm depending on the company selling them.

While future clinical research will hopefully clarify the indications for the superior capsular reconstruction and other more complex procedures, the advantages of the smooth and move procedure lie in its simplicity, its avoidance of tissue autograft or commercially available decellularized dermal allograft, its lack of postoperative 'down time', its high rate of durable improvement, and the fact that it does not preclude other surgical options should it fail to yield the desired result.

The effect of coracoacromial ligament excision and acromioplasty on the amount of rotator cuff force production necessary to restore intact glenohumeral biomechanics.

These authors point out that coracoacromial ligament (CAL) excision and acromioplasty increase superior and anterosuperior glenohumeral translation. They used a cadaver model to estimate how much of an increase in rotator cuff force is required to re-establish intact glenohumeral biomechanics after acromioplasty.

Nine cadaveric shoulders were subjected to loading in the superior and anterosuperior directions in the intact state after CAL excision, acromioplasty, and recording of the translations. The rotator cuff force was then increased to normalize glenohumeral biomechanics.

At 150 and 200 N of superior and anterosuperior loading, an increase in the rotator cuff force of 25% was required to eliminate the increased translation resulting from CAL excision.

At 150 and 200 N of superior and anterosuperior loading, an increase in the rotator cuff force of 25% and 30%, respectively, was required to eliminate the increased translation resulting from acromioplasty and CAL excision.

The authors concluded that after subacromial decompression, the rotator cuff has to increase  its force production to maintain baseline glenohumeral mechanics. Under many circumstances, in vivo force requirements may be even greater after surgical attenuation of the coracoacromial arch.

Comment: As Codman pointed out in 1934 "The coracoacromial ligament has an important duty and should not be thoughtlessly divided at any operation." 

He recognized then, as we should today, that the coracoacromial arch provides an important stabilizing function resisting the superiorly directed force applied by the deltoid or when pushing up from a chair, bed, floor or bar. He pointed to the normal articulation between the superior aspect of the cuff and the undersurface of the coracoacromial arch. 

The center of curvature of the arch is the same as the center of curvature of the humeral head.

The stabilizing effect of the arch remains the same if there is ossification of part of the coracoacromial ligament.

We have previously demonstrated that the acromion is loaded when superiorly directed force is applied through the humeral head (whether or not the cuff is intact).
 When the superior cuff tissue is absent, superiorly directed loads applied to the humeral head produce superior translation of the head until it is stopped by the coracoacromial arch.
Sacrifice of the coracoacromial arch in the cuff deficient shoulder is a common cause of anterosuperior escape and pseudoparalysis.

Where does that leave the concept of 'impingement'? See this link.