Sunday, August 30, 2015

MRI imaging of cuff tears - is 3D imaging worth it?


These authors performed a retrospective review of 34 patients with arthroscopically proven full-thickness rotator cuff tears which were classified by the surgeons with respect to tear shape:  crescent, longitudinal, U- or L-shaped longitudinal, and massive type. 

Two musculoskeletal radiologists reviewed the corresponding MRI studies to characterize the shape on the basis of the tear's retraction and size using 2D MRI. 3D reconstructions of each cuff tear were reviewed by each radiologist to characterize the shape. 

The accuracy for differentiating between crescent-shaped, longitudinal, and massive tears using measurements on 2D MRI was 70.6% for reader 1 and 67.6% for reader 2. The accuracy for tear shape characterization into crescent and longitudinal U- or L-shaped using 3D MRI was 97.1% for reader 1 and 82.4% for reader 2. When further characterizing the longitudinal tears as massive or not using 3D MRI, both readers had an accuracy of 76.9% (10 of 13). The overall accuracy of 3D MRI was 82.4% (56 of 68), significantly different (P = .021) from 2D MRI accuracy (64.7%).

Comment: "The authors assert that the shape of a rotator cuff tear can play an important role in the surgeon’s approach and election to repair as well as in the likelihood of clinical success after the repair. Having this information before surgery is useful to the surgeon as it will permit more complete surgical planning and allow the surgeon to provide prognostic information to the patient based on the surgical success of certain shaped tears.The accurate determination of the shape of the tear could also help in deciding whether the tear is reparable as well as if it would be worthwhile to proceed with surgery. In addition, a correctly defined tear shape could help determine if there is enough tendon tissue remaining to allow marginal convergence during the repair."

In trying to determine the value of the 3D reconstructions we need to know (1) whether the 3D images were predictive of the reparability of the cuff defect in these 34 patients (in other words, was the rationale proposed in the quote above demonstrated in this group of patients)? and (2) what was the incremental cost in terms of time and money for the 3D reconstructions?

It is always tempting to apply high levels of technology, but higher tech is higher cost. However, unless the increased cost produces better results for the patient, we may want to spend our precious health care on something more valuable.

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Is there sufficient PROMIS to re-invent the wheel?

Psychometric evaluation of the PROMIS Physical Function Computerized Adaptive Test in comparison to the American Shoulder and Elbow Surgeons score and Simple Shoulder Test in patients with rotator cuff disease

The National Institutes of Health has recently developed the Patient-Reported Outcomes Measurement System (PROMIS) Computer Adaptive Test (CAT) that applies technology of computerized adaptive testing used in examinations like the Graduate Records Examinations.
With CAT, questions are sequentially administered from a large item ‘‘bank’’ until predetermined reliability criteria are met. Each question response produces a probability curve of the respondent’s estimated ability. For example, a patient who can throw a ball with ease has a high probability of having upper-end physical function. Subsequent questions can then be chosen by the CAT ‘‘engine’’ that will further discriminate the respondent’s estimated ability while uninformative and repetitive questions are omitted.

These authors studied 187 patients with clinical diagnosis of rotator cuff disease completed the American Shoulder and Elbow Surgeons (ASES) score, Simple Shoulder Test (SST), and PF CAT.

Responses from 187 patients were analyzed. The PF CAT required fewer questions than the ASES or SST (PF CAT, 4.3; ASES, 11; SST, 12). Correlation between all instruments was moderately high. Item reliability was excellent for all instruments, but person reliability of the PF CAT was superior (0.93, excellent) to the SST (0.71, moderate) and ASES (0.48, fair). Ceiling effects were similar among all instruments (PF CAT, 0.53%; SST, 6.1%; ASES, 2.3%). Floor effects were found in 21% of respondents to the SST but in only 3.2% of PF CAT and 2.3% of ASES respondents.

Comment: Unfortunately the CAT requires the patient to be at a computer or tablet that carries the program. It cannot be completed on paper and thus is not amenable to follow-up mailings. The authors did not measure the time to complete the PROMIS nor its relative convenience or user-friendliness. They did not study the ability of the PROMIS responses to be translated into terms that patients can easily grasp. It is 'the new kid on the block' so that its results cannot be compared to data collected in the past.

By contrast the user-friendly Simple Shoulder Test can be completed on paper anywhere in the world in under two minutes and requires nothing other than a pencil. The SST has been utilized in over 650 publications according to a recent PubMed search. As early as ten years ago, it was recognized that this simple 12 item questionnaire had the ability to characterize (1) the function of normal shoulders, (2)  the functional deficits for many different diagnoses, and (3) the different responses of male and female patients. Here are some figures from that article that was based on 2674 patients.




Self-assessed outcome at two to four years after shoulder hemiarthroplasty with concentric glenoid reaming.

Shoulder scoring scales for the evaluation of rotator cuff repair.

It can be easily used to track patients' recovery over time.




As well as its use in multiple languages, for example


Validation and reliability of a Spanish version of Simple Shoulder Test (SST-Sp)

Finally, and perhaps most importantly, while the PROMIS score is a number without particular meaning to a patient, the results of the SST can be easily communicated:



We are not sure that the PROMIS is progress.

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Friday, August 28, 2015

Total shoulder arthroplasty - is there a reason to go 'stemless'?

Geometrical analysis of stemless shoulder arthroplasty: a radiological study of seventy TESS total shoulder prostheses.

The authors assert that stem-related complications, such as intra-operative humeral fracture, loosening, stress shielding and periprosthetic fracture can be avoided by stemless humeral implants.

They examined their ability to restore arthritic shoulder anatomy to resemble premorbid anatomy in 69 patients (70 shoulders). The mean difference between premorbid center of rotation (COR) and post-operative COR was 1 ± 2 mm (range -3 to 5.8 mm). The mean difference between premorbid humeral head height (HH) and post-operative HH was -1 ± 3 mm (range -9.7 to 8.5 mm). The mean difference between premorbid neck-shaft angle (NSA) and post-operative NSA was -3 ± 12° (range -26 to 20°).

Comment: For reasons unclear to us, there is a fascination in some parts for 'restoring premorbid anatomy' in shoulder arthroplasty. Instead our view is that the focus of shoulder arthroplasty, like that of hip and knee arthroplasty, is to durably improve mobility and stability of the articulation. This not infrequently requires making adjustments in the diameter of curvature, thickness and offset of the humeral component, rather than trying to match some vision of 'normal'. An illustration is shown in this post.

While the goal of the stemless technique is to 'prevent stem related complications', the authors do not present the complications related to their use of a stemless implant.

In comparison to a humeral component inserted with impaction autografting after conservative reaming and broaching, the use of a 'stemless' humeral component has the following disadvantages: (1) it is more technically difficult, (2) it cannot be used in cases of substantial humeral deformity and (3) it does not provide comparable access to the glenoid for glenoid arthroplasty,  

Impaction grafting of a stemmed implant minimizes the risks of stress shielding, periprosthetic fracture (on insertion or after) and loosening. The head resection with a stemmed implant provides excellent access to the glenoid. 


And finally, the modularity allows adjustment of the head size, thickness and offset to optimize the mobility and stability of the reconstruction as shown in the case below where an anteriorly eccentric head prosthesis was used to manage a tendency for posterior instability.


Reverse total shoulder after shoulder infection

Reverse Shoulder Arthroplasty for Management of Postinfectious Arthropathy With Rotator Cuff Deficiency.

These authors present a series of 8 patients having reverse total shoulders after prior shoulder infections with cuff deficiency.

Patients with a clinical presentation of an acute infection (eg, fluctuance, open draining wound) or positive cultures from joint aspiration were initially treated with open irrigation and debridement procedures. Two to 3 open irrigation and debridement procedures were completed with antibiotic spacer placement, typically 2 to 3 days apart during the same hospitalization. The number of debridement procedures performed was dictated by clinical assessment at the time of surgery as determined by the surgeon, but the minimum number of irrigation and debridement procedures for actively infected patients was 2.

Patients with a remote history of infection in the operative shoulder and negative joint aspiration cultures underwent an arthroscopic biopsy. A minimum of 5 separate biopsy specimens were sent for aerobic, anaerobic, fungal, and AFB cultures. A positive culture following arthroscopic biopsy required at least 2 open irrigation and debridement procedures with antibiotic spacer placement and 6 weeks of antibiotics prior to RSA.

All patients had rotator cuff deficiency and end-stage arthritis.





At an average follow-up of 4.4 years, no patient had a clinically detectable recurrence of infection. Significant improvements were noted in clinical outcome scores.

Comment: It is of interest that most of the infections followed cuff repairs as shown in the table. We do not know the culture protocols for the 'outside hospitals' and data were unavailable on the organism causing the infection in five cases. What is notably absent from this series of cases is evidence of Propionibacterium, now recognized to be perhaps the most common organism recovered from cases of failed cuff surgery - perhaps due to insufficient culture protocols at the outside hospitals. This leads us to realize that while these patients had no clinically detectable evidence of infection at followup, sometimes this evidence presents many years after the arthroplasty.

We are cautious in surgical reconstruction for patients with post-infectious arthritis, recognizing that one can never be sure that the infection has been resolved. We reserve a reverse total shoulder for those patients with pseudoparalysis (inability to actively elevate more than 90 degrees) or instability. We often manage patients with postinfectious arthritis without instabilty or pseudoparalysis with either a more conservative anatomic hemiarthroplasty or a CTA arthroplasty inserted using impaction grafting with Vancomycin-soaked allograft, taking at least five cultures at the time of the procedure. In the event of recurrent infection, revision of these arthroplasties is more straightforward. This approach avoids the step of using a 'spacer' if the sterility of the shoulder is uncertain.

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Imaging - making sure that the time, money and radiation benefit the patient

A few thoughts regarding the use of imaging modalities for patients with shoulder disorders.

As shoulder surgeons, we use imaging to help establish the diagnosis, to plan surgery, and to evaluate the change in shoulder anatomy with time. A robust approach to imaging the shoulder needs to recognize that (1) it is a three-dimensional structure that cannot be represented by a single planar view, (2) critical relationships - such as the degree of centering of the humeral head - change with the position of the arm, and (3) overlying and superimposed structures as well as metallic implants may complicate imaging the structures of interest. 

It is possible to spend a lot of time, money and radiation dosage on imaging, so surgeons need to develop a judicious approach that yields the information necessary to treat the patient while avoiding the tendency to ‘over image’. A currently discussed question, for example, is whether three-dimensional reconstructions based on CT scans of the arthritic shoulder help surgeons achieve better outcomes for their patients in comparison to imaging consisting only of two standardized plain films?. Or, do complex MRI analyses of cuff muscle fat content lead to better results in the management of rotator cuff lesions? While more may seem better, we need to ask whether there is an incremental benefit to the patient of the increased cost and time and radiation exposure of more elaborate imaging methods.

In imaging the possibly unstable shoulder we need to recognize that the displacement of the humeral head in relation to the glenoid is dynamic – anterior translation may be more apparent on an axillary view when the arm is extended posteriorly, posterior translation may be more apparent when the arm is adducted across the chest, superior translation may be more apparent when the deltoid is contracted isometrically, and inferior instability may be more apparent when the arm is relaxed at the side. While CT arthrography, MRI and MR arthrography with the arm adducted may reveal changes in the appearance of the labrum, they cannot reveal dynamic instability. As a result we see patients having repairs of “SLAP”, “ALPSA”, “HAGL” or “Bankart” lesions even though their symptoms were not those of instability. Only yesterday we saw a patient who demonstrated the 'MRI trap'. She had shoulder pain without a recognized injury. Had an MRI which was interpreted as showing a 'SLAP lesion'. Had a 'SLAP repair'. And now has a painful shoulder that is also very stiff.

In imaging the arthritic shoulder, a standardized anteroposterior view in the plane of the scapula and a true axillary view are often all that is necessary for diagnosis and surgical planning. The true axillary view that shows the ‘eye’ or spinoglenoid notch taken with the arm elevated in the plane of the scapula is known as the ‘truth’ view, because it reveals pathology that would not be expected when imaging (plain film or CT) is performed with the arm at the side. Two important examples are (1) the degree of joint space narrowing seen when the bald central aspect of the humeral head is opposed to the eroded posterior glenoid and (2) the functional decentering seen when the humeral head drops posteriorly into a pathologic posterior concavity (see this post). While CT scans may provide a more reproducible measure of glenoid version than standardized axillary views, it is not clear that CT images lead to any better clinical outcomes in the usual case of shoulder reconstruction. A final advantage of standardized plain films for arthritic shoulders is that the same radiographic views can be compared preoperatively and sequentially postoperatively, whereas postoperative CT scans are costly and difficult to interpret because of the metal artifacts.

So, as we move forward, we have the opportunity to ask, 'will this additional imaging study help me take better care of my patient?'; 'will the additional cost, time and radiation dose translate into a better treatment outcome?'

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Wednesday, August 26, 2015

Resection arthroplasty - a salvage procedure - a study with 50% lost to followup

Functional outcomes after shoulder resection: the patient's perspective.

These authors present followup on 7 of 14 patients having resection arthroplasty for the treatment of failed arthroplasty.

Five of the 7 patients reported satisfaction with their resection arthroplasty, and 6 of the 7 patients would undergo the procedure again if given the choice.

Comment: From this study with 50% of the patients lost to followup, it is difficult to determine the effectiveness of this procedure. We have posted before on this procedure here and here. It is of note that most of the patients having this procedure had it to manage a periprosthetic infection. 

We very rarely use either resection or spacers in the management of Propionibacterium or coagulase negative Staph infections of the shoulder, relying instead on debridement and single stage conversion to a hemiarthroplasty fixed with impaction allografting and intravenous and topic antibiotic therapy. However, the management of the infected arthroplasty requires a high level of individualization of the treatment considering the bacteria, the quality of bone, the stability of the joint, and the desires of the patient.




Total shoulder - options if at surgery the shoulder is posteriorly unstable

Outcome and value of reverse shoulder arthroplasty for treatment of glenohumeral osteoarthritis: a matched cohort.

These authors evaluated 24 patients with glenohumeral osteoarthritis scheduled to have total shoulder (TSA) but who were changed to a reverse total shoulder (RSA) because of intraoperative difficulties with the glenoid component or instability; these were compared with a cohort of 96 in which the preoperative plan for a TSA was carried through. RSA was performed when persistent posterior subluxation occurred during TSA trialing or when the glenoid trial demonstrated rocking after glenoid reaming. If the glenoid could not be reamed to a symmetric surface or if the subchondral plate was significantly violated, an RSA was placed. During the study time frame, 112 patients were identified as having undergone RSA with an intact rotator cuff.

Preoperative retroversion was approximately 7 degrees greater in the RSA group compared with the TSA group (20.8  ±  13 and 13.7  ± 11.3; P .018). Sixteen percent of patients (4 of 24) in the RSA group and 10% of patients (10 of 96) in the TSA group had preoperative retroversion > 30 degrees. However, review of the preoperative CT scans of the RSA group did not provide any guidance for the need to intraoperatively change the strategy from TSA to RSA.

Five TSA patients had radiographic glenoid loosening, whereas no RSA patients did. Neither group required a revision. One RSA patient required surgery for treatment of a periprosthetic fracture. RSA was $7274 more costly than TSA, related mainly to implant cost.

Comment: These authors present a strategy for managing the cases where the preoperative plan was to perform a total shoulder, but intraoperative problems of instability or inability to properly seat the anatomic glenoid component led to their decision to convert to a reverse total shoulder. Those patients had somewhat more retroversion than those that were managed with TSA, but preoperative CT scans were not helpful in distinguishing the two groups preoperatively (the shoulder on the left received a reverse and the shoulder on the right an anatomic TSA.


The preoperative workup did not include a standardized axillary view to evaluate functional decentering. The operative technique for an anatomic total shoulder did not include the use of anteriorly eccentric humeral heads or rotator interval plication for managing intraoperative posterior instabillity. Using these techniques, we have not had to convert from a preoperative plan for a total shoulder to the more costly reverse total shoulder.

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