Tuesday, September 30, 2014

Conversion of an anatomic to a reverse total shoulder, when is a 'platform' prosthesis of benefit?

An anatomic arthroplasty can fail for many reasons, including malposition, instability, delayed cuff failure and pseudo paralysis. In these situations consideration can be given to conversion of the anatomic prosthesis to a reverse total shoulder as shown here. As demonstrated in that post out preferred method for managing a failed anatomic arthroplasty is to completely remove the existing implant, obtain cultures, and then implant the reverse prosthesis. This approach allows full access to the glenoid and optimal positioning of the humeral component of the reverse. Removal of the anatomic implant is almost always possible and is particularly straightforward if it was inserted using impaction grafting.

In certain cases, such as that shown here, a well fixed stem can be retained and the proximal end converted to a reverse total shoulder with insertion of a glenosphere. Here's another post regarding conversion with retention of the anatomic stem.

Recently, there has been the advent of 'platform' prostheses, in which a humeral stem is fixed in the humeral canal that can be attached to either an anatomic or a reverse proximal humeral prosthesis. Several examples are shown below.

It is important to recognize that in a reverse, (1) the glenosphere is placed inferiorly on the glenoid face, (2) the proximal humeral part of the reverse is bigger than that of an anatomic humeral arthroplasty and (3) the soft tissue tensioning considerations of a reverse are different from those of an anatomic arthroplasty. Therefore, the proximal-distal positioning of the humeral component needs to be fine tuned to achieve the ideal reverse arthroplasty. While some systems provide various adaptors to adjust the height, inclination and version of the proximal humeral prosthesis, the flexibility in positioning is limited by the use of the 'platform' fixed in the humeral canal.

Fortunately, we now have a clearer understanding of the indications for a reverse total shoulder, so that the needs for convertible prostheses is diminishing. For example, it is becoming evident that proximal humeral fractures in elderly individuals are often best managed by a primary reverse total shoulder - the idea of 'trying' an anatomic arthroplasty that is convertible to a reverse later is not so appealing. Similarly, individuals with arthritis, cuff deficiency, and instability are also best managed by a primary reverse.

Consultation for those who live a distance away from Seattle.

Click here to see the new Shoulder Arthritis Book

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To see the topics covered in this Blog, click here

Use the "Search" box to the right to find other topics of interest to you.

You may be interested in some of our most visited web pages including:shoulder arthritis, total shoulder, ream and runreverse total shoulderCTA arthroplasty, and rotator cuff surgery as well as the 'ream and run essentials'

Monday, September 29, 2014

Shoulder Arthritis: The Cliff Notes for Physical Therapists and Other People

Glenohumeral Arthritis

The Cliff Notes for Physical Therapists and Other People

For the complete Shoulder Arthritis Book, click here.

I. Anatomy and mechanics – the glenohumeral joint represents a wonderful balance of mobility and stability. The socket is very shallow so that the humeral head is stabilized by concavity compression in which the cuff muscles press the ball into the socket. In the normal shoulder about 2/3rds of the motion is at the glenohumeral joint and 1/3 at the scapulothoracic joint. We are humbled by the challenge of trying to ‘fix’ this complex joint when it goes awry.

II. Definition – glenohumeral arthritis is a condition in which the articular cartilage normally covering the humeral head and glenoid is compromised. There are different types of shoulder arthritis. Usually it is not an inflammatory condition – such as rheumatoid arthritis - as the ‘-itis’ implies, but rather a degenerative, post traumatic or post surgical condition. Other diagnoses often lumped in with glenohumeral arthritis include avascular necrosis, cuff tear arthropathy, post-septic arthritis and chondrolysis from the intra-articular infusion of local anesthetics. Glenohumeral arthritis needs to be distinguished from two other common diagnoses, frozen shoulder and rotator cuff tear.

III. Presentation - glenohumeral arthritis causes loss of comfort and function of the shoulder. A practical way to assess the functional loss of an arthritic glenohumeral joint is with the Simple Shoulder Test (SST) . The SST is a valuable tool and the patient’s responses should be recorded at each visit to the therapist.

Summarizing the SST responses for over three thousand patients presenting for shoulder arthroplasty, we find the following percentages of patients able to perform each of the functions.

IV. Diagnosis – the diagnosis of glenohumeral arthritis requires a good history, examination of the active and passive ranges of motion and proper standardized x-rays. The history should elicit past trauma, prior treatment, prior shoulder surgery, systemic disease, medications (such as steroids), and involvement of other joints. The range of active and passive abduction, flexion, cross body adduction, reach up the back, external rotation at the side, and internal rotation of the abducted arm are usually diminished in glenohumeral arthritis. In performing these examinations, it is important to determine how much of the motion is humeroscapular and how much of the motion is scapulothoracic. The technique for taking the key x-rays for documenting the presence of arthritis is shown here. Here are examples of an AP view and an axillary view showing a normal joint space and the absence of bone spurs.

By contrast, an osteoarthritic glenohumeral joint often shows osteophytes, loose bodies, glenoid retroversion, glenoid biconcavity, and posterior subluxation of the humeral head on the glenoid as shown here.

See also this post that shows the x-ray characteristics of the different types of glenohumeral arthritis. One of the most difficult diagnoses to manage is chondrolysis resulting from the intra-articular infusion of local anesthetics with a pain pump. This condition is devastating because it occurs in young individuals having instability surgery, because it can completely destroy the articular cartilage, and because it is usually accompanied by soft tissue disease that results in pain and stiffness, even after joint replacement. Other challenging diagnoses are post-traumatic or post-surgical arthritis – both of which can distort the local anatomy requiring special modifications of the standard procedure that would be used for straightforward osteoarthritis. Shoulder arthroplasty for rheumatoid arthritis may be complicated by the soft bone, the fragile rotator cuff, severe bone erosion, and shoulder tightness.

V. Progression – glenohumeral osteoarthritis (the most common form in the U.S.) usually starts subtly with only minor symptoms at night or during certain activities. It then progresses at a highly variable rate – sometimes not changing from year to year, sometimes with a sudden worsening and sometimes with an up and down course over the seasons or years. On occasion the x-rays may appear much worse than the symptoms. “End stage” arthritis can leave the glenohumeral joint without any range of motion.

VI. Evaluation – as William Osler said, ‘it is as important to know what patient the disease has than what disease the patient has’. We are on the lookout for the 3 “D”s, diseases, depression, and dependency on nicotine, narcotics or alcohol, which can compromise the patient’s ability to respond to non-operative or operative management. The best prognostic factors are a healthy patient with a positive attitude and good social support. Patient selection is the principal key to successful surgery.

VII. Non-operative management – because surgery for glenohumeral arthritis is elective, patients have plenty of time to try to optimize their comfort and function with non-operative management. We focus on three areas of patient self-management: (1) avoidance of impact and heavy compressive loading, (2) range of motion – (exercises A,B,C,E,F,G and L on this post). and (3) traction exercises. We do not use glucosamine, chondroitin, cortisone injections, hyaluronic acid injections, ultrasound, or muscle stimulation. Non-steroidal anti-inflammatory medications may be useful, but caution is exerted to avoid cardiac, renal, liver, gastric and hematological complications. See also this post on non surgical management..

VIII. Surgical options – the different surgical procedures for glenohumeral arthritis are discussed in detail here. The first consideration is whether it is appropriate to consider surgical treatment at this time. . Shoulders with bad looking x-rays are not taken to the operating room if the patient doesn’t have substantial functional deficits, if the patient is not a good candidate for surgery for health or social reasons, if the patient does not wish to accept the risks of surgery, or if the surgeon is not comfortable with what needs to be done. The common forms of arthroplasty and the common conditions for which they are performed are listed below and here.

a. Hemiarthroplasty – avascular necrosis when the glenoid is intact

b. Total shoulder arthroplasty – osteoarthritis, rheumatoid arthritis, capsulorrhaphy arthropathy, post traumatic arthritis

c. Ream and run - osteoarthritis, capsulorrhaphy arthropathy, posttraumatic arthritis in patients wishing to avoid the risks and limitations associated with a prosthetic polyethylene glenoid component.

d. Cuff tear arthropathy (CTA) arthroplasty – this procedure is used for the arthritic, cuff deficient shoulder that has an intact, stabilizing coracoacromial arch.

e. Reverse total shoulder – rotator cuff tear arthropathy, pseudoparalysis, failed total shoulder arthroplasty with rotator cuff insufficiency. Patients considering this procedure are cautioned about the limited range of motion and function usually achieved with this surgery and also about the increased risk of fracture or fixation failure with falls.

Each of these procedures modifies the arthritic anatomy by removing abutting bone, and inserting smooth prosthetic joint surfaces that enable motion, stability and load transfer. Each procedure involves careful balancing of the capsule and other surrounding soft tissues. The procedure may include a biceps tenotomy or tenodesis if the long head tendon of the biceps is frayed or unstable.

The use of these different surgical options varies widely among different surgeons. This variation in use confounds the development of appropriateness criteria and the evaluation of outcomes. For example, surgeons who use the reverse total shoulder for milder disease will have better results than those who use it primarily after a salvage procedure after more conservative procedures have failed or when there is no other option.

IX. Postoperative care – the rehabilitation program after surgery depends on the details of the surgery performed, the specific findings at surgery, and the patient. In our practice we try to standardize and simplify the postoperative program for almost all arthroplasties. We use continuous passive motion while the patient is in the hospital and start assisted elevation the evening of surgery. Our goal is to have the patient be able to perform assisted elevation to at least 150 degrees by the time of discharge on the second postoperative day. Forward elevation stretches are done 5 times a day with a 2 minute hold. We do not work on external rotation range until after six weeks, allowing for solid healing of the subscapularis repair and then we only have the patient do very gentle stretching At six weeks we often add all of the exercises shown here. Gentle progressive strengthening is progressed from there, make sure that any exercise can be repeated at least 20 times. This program is modified if there are concerns about instability or the quality of the repairs. If the shoulder is stiff at six weeks, we consider a closed manipulation. After a reverse total shoulder we immobilize the arm in a sling for six weeks and then allow the patient to progress with gentle activities of daily living.

X. Complications – surgery for glenohumeral arthritis may yield unsatisfactory results or be associated with complications as shown here. These complications may include persistent pain, nerve injury, cuff or subscapularis failure, stiffness, instability, fracture, component loosening and infection.

XI. Expected outcomes – the results of glenohumeral arthroplasty are determined by the characteristics of (1) the shoulder problem, (2) the patient, (3) the procedure and (4) the team providing the care. We refer to these as the 4P s. We let patients know we cannot guarantee a specified result, but we do assure them of our best efforts to improve their shoulder’s comfort and function.

XII. The future – much hope has been placed on ‘biological resurfacing’ with interpositional grafts of cadaver meniscus or artificial materials. These however have get to yield durable results, probably because of the mortar and pestle action of the humeral head and glenoid on the interposed material. While ‘tissue-engineering’ sounds attractive, attempts to grow cartilage and implant it in a human joint have been frustrated. The most promising regenerative procedure in our view is the ream and run procedure in which the healing response of concentrically reamed glenoid bone is molded by a smooth, round humeral head prosthesis. This procedure appears to enable the glenoid to cover itself with fibrocartilage bonded to the underlying bone.

XIII. Role of the therapist – in a word, essential. Ideally the patient and therapist get to know each other before surgery, sharing the program and the plan for ongoing communication. In the hospital the therapist starts the rehab program and assures the patient is ‘on top of it’ before discharge. After discharge the therapist is available on an ongoing basis for answering questions, measuring progress, and alerting the surgeon to any deviations from the expected recovery.

Friday, September 26, 2014

Intra-articular antibiotics as prophylaxis in total shoulder arthroplasty

Intraoperative intra-articular injection of gentamicin: will it decrease the risk of infection in total shoulder arthroplasty?

These authors conducted a retrospective study of 507 shoulder arthroplasties (433 primary and 71 revisions) performed between 2005 and 2011. All patients received Cefazolin (or Clindamycin or Vancomycin) intravenous prophylaxis. In 343 patients operated after June 2007, 160 mg of gentamicin in 20 mL of saline was injected into the joint just before closure.

These cases were reviewed for evidence of deep postoperative infection within 6 month of surgery as evidenced by increasing pain, elevated erythrocyte sedimentation rate and Creactive protein level, clinical appearance of infection at the time of surgery, possible positive culture, and more than 10 white blood cells per high-power field.

Six shoulders were thought to have developed infection, one with Staph aureus, one with Methacillin resistant Staph aureus and one with Staph epidermidis.  In three cases the cultures were negative. Five of these cases were operated before June 2007 and one after.

Comment: The use of topical antibiotics to reduce the risk of infection in shoulder arthroplasty is receiving increased attention as shown here. This approach makes sense in that high local concentrations can be achieved without the risk of systemic complications, at least initially (we don't know how long injected or sprinkled antibiotics will hang around in the wound before reabsorption). In this study half of the cases showing signs of infection were culture negative, so we can't be sure that bugs were really there. It is also of note that although the demographics of the patients operated before and after June of 2007 were similar, the surgeon and the team caring for the patients later in the series were more experienced than for the patients earlier in the series. For example, it is possible that open wound times became shorter over the duration of the study, a factor that could also lower the risk of infecton. Finally, the culture protocols for this study were not specified. We know that many apparently 'aseptic' revisions are actually culture positive. The organism accounting for the preponderance of positive cultures at revision arthroplasty is Propionibacterium - this organism requires special means for detecting its presence.  Surprisingly, none of these cases were culture positive for this most common arthroplasty infector.

Thursday, September 25, 2014

Celebrating the 1000th post on the shoulder blog with something special

We thought we'd celebrate with two of our favorite forms of trout.

One is shown here


Humeral head subluxation in osteoarthritis

Importance of a three-dimensional measure of humeral head subluxation in osteoarthritic shoulders.

As the authors point out, the management of posterior humeral subluxation can be a challenge in shoulder arthroplasty. Persistent posterior instability can contribute to cold-flow and wear of the posterior lip of the glenoid component as well as to rocking horse loosening of the glenoid component in total shoulder arthroplasty.

These authors analyzed 112 computed tomography scans of osteoarthritic shoulders. They compared the 2D and 3D assessments of humeral head subluxation and glenoid version. They defined the 3D glenohumeral subluxation as the relative distance between the humeral head center and the glenoid center projected onto a plane perpendicular to the glenoid centerline. They defined the 3D scapulohumeral subluxation with the same distance but projected onto a plane perpendicular to the scapular axis. They found that scapulohumeral subluxation correlated with glenoid version, but that glenohumeral subluxation was not correlated to glenoid version.

The authors concluded that the direction of humeral subluxation was rarely within the usual computed tomography plane and should therefore be measured in 3D to detect out-of-plane subluxation. 

Comment: Several points need to be made. (1) A CT scan looks at the shoulder with the arm at the side, yet this is not the position in which posterior humeral subluxation occurs. Rather posterior humeral subluxation occurs when the arm is elevated to a position of function, say 60 degrees of elevation in the scapular plane where the posteriorly directed deltoid force challenges the posterior stability. CT scan is not useful with the arm in this position, but a standardized axillary view works very well as shown here. (2) The relationship of the center of the humeral head to the glenoid surface or to the plane of the scapula is not the primary concern in posterior subluxation. Rather the factor that produces posterior wear and rocking horse loosening is the posterior point of contact of the humeral head on the glenoid as shown here.  Fortunately this point of contact is simple to measure on a standardized axillary view and does not require spending money or radiation on CT scans, 3D reconstructions, or debate on whether the scapula or the glenoid is the proper reference.

We routinely use the 'truth' view rather that CT scans to understand the glenohumeral pathoanatomy prior to shoulder arthroplasty.

Death and morbidity after total shoulder arthroplasty - risk factors

Thirty-day morbidity and mortality after elective total shoulder arthroplasty: patient-based and surgical risk factors.

These authors queried the National Surgical Quality Improvement Program database to identify all patients undergoing primary TSA between 2006 and 2011, extracting selected patient and surgical variables along with the 30-day clinical course.

2004 patients with total shoulders were identified with an average age of 69 years. 57% were women. 46% were obese and 48% had an American Society of Anesthesiologists (ASA) classification of ≥3. The 30-day mortality and total complication rates were 0.25% and 3.64%, respectively.

Comorbid cardiac disease and increasing age were independent predictors of mortality. Complications were increased 6 fold in the presence of peripheral vascular disease and 4 fold when operative time was 3 or more hours. The most common surgical complications were infection and peripheral nerve injury. 

Obesity was not a significant risk factor.

Comment: This study reveals that total shoulders are often performed on individuals who are not in good health. Almost half were classified as having an ASA class reflecting "severe or life-threatening disturbance" of their health. Over 2/3 rds had hypertension, 16% had diabetes, and 11% had major cardiac issues.
Patients with such factors deserve special counseling regarding the risk of complications and special surveillance for the occurrence of adverse events, such as pulmonary emboli, sepsis, strokes, cardiac events and renal failure

Use of a ream and run to manage the bad arthritic triad without changing glenoid version.

Here's a brief report of a case from this week's OR. A large, strong, man in his mid sixties presented to the office requesting a ream and run for his arthritic shoulder.

His preoperative films showed synovial chondromatosis
and a retroverted, biconcave glenoid with posterior humeral subluxation on the glenoid face (= the bad arthritic triad).

 His ream and run procedure included the use of a rotator interval plication and an anteriorly eccentric humeral head.

Note that his humeral head was centered even though his glenoid version was not changed.

He was discharged on his second postop day with a comfortable 150 degrees of assisted elevation.

Consultation for those who live a distance away from Seattle.

Click here to see the new Shoulder Arthritis Book

Click here to see the new Rotator Cuff Book

To see the topics covered in this Blog, click here

Use the "Search" box to the right to find other topics of interest to you.

You may be interested in some of our most visited web pages including:shoulder arthritis, total shoulder, ream and runreverse total shoulderCTA arthroplasty, and rotator cuff surgery as well as the 'ream and run essentials'