Wednesday, August 10, 2016

Hemiarthroplasty vs total shoulder - an example of factors to consider.

A recent post (see this link) discussed an economic decision model for comparing hemiarthroplasty to total shoulder. While this article presented an interesting approach, our post surfaced some concerns about the methodology and generalizabilty of the results.

We concluded, "We might wonder why a surgeon would choose a HA over a TSA for patients such as those included in the recently published model, especially since the surgeon's reimbursement is greater for the TSA. Possible reasons would include surgeon inexperience with TSA, a diagnosis of avascular necrosis, complex anatomy or shoulder tightness that precluded the use of a TSA, patient's desire to avoid the activity limitations typically imposed on individuals with TSAs, or concern about cuff deficiency. Interestingly, each of these reasons could contribute to inferior outcomes, higher revision rates, and greater costs for patients having HA in contrast to other patients having TSA. "

We saw an illustrative case today of an active person who had done farm work for 20 years. She presented a year ago with an unusually advanced shoulder arthritis. She answered "no' to 11 out of 12 questions on the Simple Shoulder Test. Her x-rays at the time of presentation to us are shown below.

This shoulder was so tight and medially eroded, we elected a hemiarthroplasty rather than a total shoulder.

One year after surgery she answers "yes' to 10 of the 12 questions of the Simple Shoulder Test and is most pleased with the result.

We show this as an example of the ever present need to customize the treatment to the patient.


Tuesday, August 9, 2016

The 'critical' shoulder angle- cause or effect of shoulder pathology?

Predominance of the critical shoulder angle in the pathogenesis of degenerative diseases of the shoulder.

In 200 patients these authors measured the angle between a line connecting the inferior margin to the superior margin of the glenoid fossa and a second line connecting the inferior margin of the glenoid fossa to the lateral margin of the acromion.

The average angle was 34° ± 3° in the control group, 36° ± 3° with supraspinatus tears, 40° ± 3.5° with supraspinatus and infraspinatus tears, and 28° ± 2° with concentric osteoarthritis. Patients with large cuff tears had significantly greater angles compared with those with isolated supraspinatus tears (P = .03). The angle was associated with cuff tears (odds, 1.7; confidence interval [CI], 1.4-2.0). The Spearman coefficient between the angle and grade of eccentric osteoarthritis was 0.4 (P = .01). 

Larger angles were associated with increased rate of symptomatic cuff tears, larger cuff tears, and the severity of eccentric osteoarthritis. Smaller angles increased the risk and severity of concentric symptomatic osteoarthritis. These associations remained significant even after removal of some of the potentially confounding variables.

Comment: While it has been suggested that this angle is "responsible" for the occurrence of cuff tears and concentric osteoarthritis when the angle is significantly different from the corresponding angle in normal shoulders, we observe that this study demonstrates association but not causation. It seems more likely that changes in the angle are the result of the shoulder pathology rather than its cause. In that regard, it would be of interest to compare the shoulder angles between the pathological shoulder and the contralateral shoulder in the same subject to see if the angle was developmental or acquired.

For those readers interested in proving causation, this link will be of interest.

Arthroscopic rotator cuff repair - types of complications

Complications associated with arthroscopic rotator cuff tear repair: definition of a core event set by Delphi consensus process

These authors conducted a Delphi consensus process with an international panel of experienced shoulder surgeons to develop an organized list of complications of arthroscopic rotator cuff repair (ARCR) occurring within two years after surgery.

The events were categorized as follow: 

  fixation device - malposition, displacement

  osteochondral - arthritis, cuff tear arthropathy, osteonecrosis, chondrolysis, acromioclavicular arthritis, fracture, loose body, bone cyst, osteolysis, chondromalacia

  persistent or worsening pain

  rotator cuff - recurrent or new tear

  peripheral nerve problem - nerve injury, complex regional pain syndrome

  vascular - hematoma, thrombosis

  infection - superficial, deep

  skin - wound healing issues, keloid

  deep soft tissue - subacromial adhesions, biceps, stiffness, deltoid

Comment: Our understanding of the complications of shoulder surgery has been compromised by the lack of a standardized system for identifying and recording these events. This is a well thought out list relating to arthroscopic cuff repair. General application of this schema will show us the most important and most common complications, the factors associated with them and how they can best be avoided and treated.

It would be most useful to have a similarly developed list of the complications following other shoulder procedures, such as arthroplasty, instability repairs, and fracture surgery. 

Thursday, August 4, 2016

Non-operative treatment of shoulder arthritis with posterior decentering (subluxation)

Today this email came in:

"We met several months ago. Dr. X had recently completed a cortisone procedure on my left and arthritic shoulder. As I recall when you analyzed my x-ray you noted that my humerus bone was posterior in the socket and as a consequence mobility was restricted and plenty of crepitus based on the the bone moving in the unintended part of the socket. Irrespective of the type of initial dislocation you explained that the bone is mis-placed and remains there (due If guess to the composite if all existing forced from damaged/weak muscles, tendons, etc). You offered to try to respond by email to follow-up questions that I might have.

I'd like to learn exactly which physical exercises might rebuild or retrain my physiology in such a way that the bone would find a new and better equilibrium in its socket (that enables improved mobility and less bone-on-bone wear that is undoubtedly taking place). I would like your advice or referral of a therapist with solid experience relating to shoulder anatomy and damage. For the most part I've only encountered PTs who described standard exercises that offered negligible value. They had no regard to exact status of my condition and had no ability to develop a treatment trajectory that would be optimal.

I look forward to your thoughts."

Comment: Posterior humeral decentering (subluxation) is a common feature of glenohumeral osteoarthritis

Once the glenoid develops a pathologic posterior concavity, the humeral head tends to fall into it when the arm is elevated to a functional position as shown in the three 'truth views' above. The deeper the posterior concavity, the less likely it is that exercises can help.

For early stages of arthritis, we recommend avoiding pushups, bench presses and other pushing exercises while focusing on external rotator strengthening so that the posterior rotator cuff muscles can help resist the tendency for the shoulder to slide out of the back of the joint. See below

as well as stretching exercises to minimize stiffness (see this link). We do not use steroid or other injections into the shoulder joint.

Wednesday, August 3, 2016

Shoulder joint replacement arthroplasty - avoid problems by slimming the stem

This x-ray shows arthritis of the left shoulder.

It was treated elsewhere with a total shoulder using a large stemmed humeral component. Post operative films show that use of this humeral prosthesis appears to (1) have caused a fracture of the tuberosity (arrow) and (2) have prevented full seating because of diaphyseal tightness.

The fractured tuberosity resorbed (arrow).

Leaving the shoulder with cuff deficiency, pseudoparalysis, and rocking horsing of the glenoid (arrow).

Our preference is to minimize the risk of these problems by using a slim stem fixed with impaction grafting in both total shoulder replacement

And in the ream and run procedure


Monday, August 1, 2016

Large/massive cuff tears: Reverse total shoulder or arthroscopic repair?

Cost-Effectiveness of Reverse Total Shoulder Arthroplasty Versus Arthroscopic Rotator Cuff Repair for Symptomatic Large and Massive Rotator Cuff Tears.

The authors compared the cost-effectiveness of attempted arthroscopic rotator cuff repair versus reverse total shoulder arthroplasty in patients with symptomatic large and massive rotator cuff tears without cuff-tear arthropathy.

The input variables to their model are shown in the figure below. Note the retear rate after attempted arthroscopic repair is estimated at 68.5%

It is very interesting to look at the clinical states modeled, for example, the ASES scores assigned to cuff repair with and without retear are essentially the same.

They concluded that both attempted arthroscopic rotator cuff repair and reverse total shoulder were superior to nonoperative care, with an incremental cost-effectiveness ratio (ICER) of $15,500/quality-adjusted life year (QALY) and $37,400/QALY, respectively. Attempted arthroscopic rotator cuff repair was dominant over primary reverse total shoulder arthroplasty, with lower costs and slightly improved clinical outcomes even though over two thirds of these repair attempts would fail to re-establish the rotator cuff attachment to bone.

In their analysis arthroscopic rotator cuff repair was the preferred strategy as long as the lifetime progression rate from retear to end-stage cuff-tear arthropathy was less than 89%. However, when the model was modified to account for worse outcomes when reverse shoulder arthroplasty was performed after a failed attempted rotator cuff repair, primary reverse total shoulder had superior outcomes with an ICER of $90,000/QALY.

The authors concluded that attempted arthroscopic rotator cuff repair may be a more cost-effective initial treatment strategy when compared with primary reverse total shoulder arthroplasty despite high rates of tendon retearing for patients with large and massive rotator cuff tears.

Comment: As the readers of this blog know, we have found a secure place in our practice for the 'smooth and move' procedure for large and massive cuff tears - avoiding the cost and the rehabilitation of a cuff repair. See this link. This approach seems particularly attractive in light of the observation that less than 1/3 of attempted repairs of these tears are successful, so the effort to 'repair' the tear may not be worth it.

Readers will be interested in a prior relevant post (see this link).


Propionibacterium - the most common bacterium recovered from failed shoulder arthroplasties. Treatment with a spacer.

Definitive Treatment of Infected Shoulder Arthroplasty With a Cement Spacer.

These authors present 9 patients from a single institution who had an infected shoulder arthroplasty. The culture results show that 6 out of the 9 cases were culture positive for Propionibacterium - interestingly one was P. Granulosum rather than P. Acnes. Of the 9 patients in this study, 6 were men. Mean age was 73±9 years. Of the study patients, 1 had diabetes, 2 presented with Parkinson's disease, and 5 had a history of tobacco use. Average body mass index was 27.9±7 kg/m2.

This report describes management with a cement spacer consisting of gentamicin-impregnated polymethyl methacrylate around an AISI 316L stainless steel core. 

All patients had a minimum of 2 years of follow-up.  After mean follow-up of 4 years, none of the patients had clinical or radiographic evidence of infection. Functional outcomes, as measured by American Shoulder and Elbow Surgeons scores, were good or fair in 89% of patients, and the average American Shoulder and Elbow Surgeons score was 57. A review of recent literature suggested that the current findings were similar to those in studies reporting 1- or 2-stage revision procedures. Although cement spacers are typically used as part of a 2-stage revision procedure, the authors suggest that cement spacers can be used effectively to eradicate infection and allow for acceptable functional recovery and range of motion in patients who have severe medical comorbidities and cannot tolerate additional surgery (see the example below of the use of a spacer to manage the infected hemiarthroplasty in an 87 year old man).

Comment: In spite of intense interest in determining the ideal management of failed shoulder arthroplasties with positive cultures for Propionibacterium, the role of single stage prosthesis exchange (see this link), exchange first with a spacer and then a prosthesis at a second stage (two-stage exchange), or, as presented here, a single stage exchange with a spacer. Because of the propensity of this organism to form a biofilm, it is likely that removal of all colonized implants is an important step. Whether it is better to then insert a spacer or a new implant remains unclear. One of the downsides of a 'permanent' space, as the authors of this article point out, is the possibility of glenoid erosion from articulation with the spacer.