Joseph P. Iannotti

A standardized method for the assessment of shoulder function

The American Shoulder and Elbow Surgeons have adopted a standardized form for assessment of the shoulder. The form has a patient self-evaluation section and a physician assessment section. The patient self-evaluation section of the form contains visual analog scales for pain and instability and an activities of daily living questionnaire. The activities of daily living questionnaire is marked on a four-point ordinal scale that can be converted to a cumulative activities of daily living index. The patient can complete the self-evaluation portion of the questionnaire in the absence of a physician. The physician assessment section includes an area to collect demographic information and assesses range of motion, specific physical signs, strength, and stability. A shoulder score can be derived from the visual analogue scale score for pain (50%) and the cumulative activities of daily living score (50%). It is hoped that adoption of this instrument to measure shoulder function will facilitate communication between investigators, stimulate multicenter studies, and encourage validity testing of this and other available instruments to measure shoulder function and outcome.

The normal glenohumeral relationships. An anatomical study of one hundred and forty shoulders.

We measured the dimensions of the humeral and glenoid articular surfaces in 140 shoulders that were representative of a given population of patients, and also evaluated several glenohumeral relationships. Ninety-six measurements were made in the shoulders of cadavera and forty-four, on magnetic resonance-imaging studies of living patients. Eighty-five per cent of the humeral measurements fell within eight fixed combinations of the radius of curvature and the thickness of the humeral head, in two-millimeter increments. The average radius of curvature of the humeral head in the coronal plane was 24 +/- 2.1 millimeters (range, nineteen to twenty-eight millimeters). The average thickness of the humeral head was 19 +/- 2.4 millimeters (range, fifteen to twenty-four millimeters). There was a wide variability in the size of the humeral head and a direct correlation between the differences in size and the heights in both men and women. The humeral articular surface was spherical in the center; however, the peripheral radius was two millimeters less in the axial plane than in the coronal plane. Thus, the peripheral contour of the articular surface was elliptical (ratio, 0.92). The radius of curvature of the glenoid, measured in the coronal plane, was an average of 2.3 +/- 0.2 millimeters greater than that of the humeral head. The average dimensions of the glenoid in the superior-inferior and anterior-posterior (lower half) directions were 39 +/- 3.5 millimeters (range, thirty to forty-eight millimeters) and 29 +/- 3.2 millimeters (range, twenty-one to thirty-five millimeters). The anterior-posterior dimension of the glenoid was pear-shaped, the lower half being larger than the top half. The ratio of the lower half to the top half was 1:0.80 +/- 0.01. There was a strong linear correlation between the lateral humeral offset and the size of the humeral head (radius of curvature and thickness). The average lateral humeral offset was 56 +/- 5.7 millimeters (range, forty-three to sixty-seven millimeters). The superior most point on the humeral articular surface was an average of 8 +/- 3.2 millimeters (range, three to twenty millimeters) cephalad to the top of the greater tuberosity. Our data show that reconstruction of the lateral humeral offset is important in optimization of the moment arm of the deltoid and rotator cuff and of the normal tension of the soft tissue after prosthetic reconstruction.

Magnetic resonance imaging of the shoulder. Sensitivity, specificity, and predictive value.

The sensitivity, specificity, and predictive value of magnetic resonance imaging in the diagnosis of lesions of the rotator cuff, glenohumeral capsule, and glenoid labrum were evaluated in ninety-one patients and fifteen asymptomatic volunteers. Magnetic resonance imaging demonstrated 100 per cent sensitivity and 95 per cent specificity in the diagnosis of complete tears, and it consistently predicted the size of the tear of the rotator cuff. There was a definite correlation between atrophy of the supraspinatus muscle and the size of a complete, chronic tear of the rotator cuff. The sensitivity and specificity of magnetic resonance imaging in the differentiation of tendinitis from degeneration of the cuff were 82 and 85 per cent, and in the differentiation of a normal tendon from one affected by tendinitis with signs of impingement the sensitivity and specificity were 93 and 87 per cent. The formation of spurs around the acromion and acromiocalvicular joint correlated highly with increased age of the patient and with chronic disease of the rotator cuff. The sensitivity and specificity of magnetic resonance imaging in the diagnosis of labral tears associated with glenohumeral instability were 88 and 93 per cent. The study showed that high-resolution magnetic-resonance imaging is an excellent non-invasive tool in the diagnosis of lesions of the rotator cuff and glenohumeral instability.

Influence of preoperative factors on outcome of shoulder arthroplasty for glenohumeral osteoarthritis.

Background: The results of shoulder arthroplasty for osteoarthritis have been reported to be excellent or good for the majority of patients, but the value of using a glenoid component and the anatomic factors that affect outcome are still debated. The purpose of this study was to evaluate the influence of an operatively confirmed full-thickness tear of the rotator cuff, the severity of preoperative erosion of glenoid bone, preoperative radiographic evidence of subluxation of the humeral head, and the severity of preoperative loss of the passive range of motion on the outcome of total shoulder arthroplasty and hemiarthroplasty.Methods: In a multicenter clinical outcome study, we evaluated 128 shoulders in 118 patients with primary osteoarthritis who had been followed for a mean of forty-six months (range, twenty-four to eighty-seven months).Results: Patients with <10° of passive external rotation preoperatively had significantly less improvement in external rotation after hemiarthroplasty (p = 0.006). Thirteen (10%) of the 128 shoulders had a repairable full-thickness tear of the supraspinatus tendon, but these tears did not affect the overall American Shoulder and Elbow Surgeons score, the decrease in pain, or patient satisfaction. Severe or moderate eccentric glenoid erosion was seen in twenty-nine (23%) of the 128 shoulders, and total shoulder arthroplasty resulted in significantly better passive total elevation and active external rotation as well as a trend toward significantly better active forward flexion than did hemiarthroplasty in these shoulders. The humeral head was subluxated posteriorly in twenty-three shoulders (18%), and when they were compared with the other shoulders in the study, these shoulders were found to have lower final American Shoulder and Elbow Surgeons scores, more pain, and decreased active external rotation following either total shoulder arthroplasty or hemiarthroplasty.Conclusions: On the basis of our data, we recommend the use of a glenoid component in shoulders with glenoid erosion. Humeral head subluxation was associated with a less favorable result regardless of the type of shoulder arthroplasty and must be considered in preoperative planning and counseling. Severe loss of the passive range of motion preoperatively was associated with a decreased passive range of motion postoperatively. A repairable tear of the supraspinatus tendon is not a contraindication to the use of a glenoid component.Level of Evidence: Prognostic study, Level I-1 (prospective study). See Instructions to Authors for a complete description of levels of evidence.

Commercial extracellular matrix scaffolds for rotator cuff tendon repair : Biomechanical, biochemical, and cellular properties

BACKGROUND We are not aware of any in vitro study comparing the biomechanical, biochemical, and cellular properties of commercial extracellular matrix materials marketed for rotator cuff tendon repair. In this study, the properties of GraftJacket, TissueMend, Restore, and CuffPatch were quantified and compared with each other. The elastic moduli were also compared with that of normal canine infraspinatus tendon. METHODS Samples were tested from different manufacturing lots of four materials: GraftJacket (ten lots), TissueMend (six), Restore (ten), and CuffPatch (six). The Kruskal-Wallis test was used to compare thickness, stiffness, and modulus as well as hydroxyproline, chondroitin/dermatan sulfate glycosaminoglycan, hyaluronan, and DNA contents among these matrices. The moduli of the extracellular matrices were also compared with those of normal canine infraspinatus tendon. RESULTS All four extracellular matrices required 10% to 30% stretch before they began to carry substantial load. Their maximum moduli were realized in their linear region at 30% to 80% strain. The elastic moduli of all four commercial matrices were an order of magnitude lower than that of canine infraspinatus tendon. TissueMend had significantly higher DNA content than the other three matrices (p<0.0001), although both Restore and GraftJacket also had measurable amounts of DNA. CONCLUSIONS Our data demonstrate chemical and mechanical differences among the four commercial extracellular matrices that we evaluated. Probably, the source (dermis or small intestine submucosa), species (human, porcine, or bovine), age of the donor (fetal or adult), and processing of these matrices all contribute to the unique biophysical properties of the delivered product. The biochemical composition of commercial extracellular matrices is similar to that of tendon. However, the elastic moduli of these materials are an order of magnitude lower than that of tendon, suggesting a limited mechanical role in augmentation of tendon repair.

A standardized method for assessment of elbow function

The American Shoulder and Elbow Surgeons have adopted a standardized form for assessment of the elbow. This form was developed by the Research Committee of the American Shoulder and Elbow Surgeons and subsequently adopted by the membership. The patient self-evaluation section contains visual analog scales for pain and a series of questions relating to function of the extremity. The responses to the questions are scored on a 4-point ordinal scale. The physician assessment section has 4 parts: motion, stability, strength, and physical findings. It is hoped that adoption of this method of data collection will stimulate multicenter studies and improve communication between professionals who assess and treat patients with elbow disorders.

Evaluation of the Neer System of Classification of Proximal Humeral Fractures with Computerized Tomographic Scans and Plain Radiographs

The intraobserver reliability and interobserver reproducibility of the Neer classification system were assessed on the basis of the plain radiographs and computerized tomographic scans of twenty fractures of the proximal part of the humerus. To determine if the observers had difficulty agreeing only about the degree of displacement or angulation (but could determine which segments were fractured), a modified system (in which fracture lines were considered but displacement was not) also was assessed. Finally, the observers were asked to recommend a treatment for the fracture, and the reliability and reproducibility of that decision were measured. The radiographs and computerized tomographic scans were viewed on two occasions by four observers, including two residents in their fifth year of postgraduate study and two fellowship-trained shoulder surgeons. Kappa coefficients then were calculated. The mean kappa coefficient for intraobserver reliability was 0.64 when the fractures were assessed with radiographs alone, 0.72 when they were assessed with radiographs and computerized tomographic scans, 0.68 when they were classified according to the modified system in which displacement and angulation were not considered, and 0.84 for treatment recommendations; the mean kappa coefficients for interobserver reproducibility were 0.52, 0.50, 0.56, and 0.65, respectively. The interobserver reproducibility of the responses of the attending surgeons regarding diagnosis and treatment did not change when the fractures were classified with use of computerized tomographic scans in addition to radiographs or with use of the modified system in which displacement and angulation were not considered; the mean kappa coefficient was 0.64 for all such comparisons. Over-all, the addition of computerized tomographic scans was associated with a slight increase in intraobserver reliability but no increase in interobserver reproducibility. The classification of fractures of the shoulder remains difficult because even experts cannot uniformly agree about which fragments are fractured. Because of this underlying difficulty, optimum patient care might require the development of new imaging modalities and not necessarily new classification systems.

The acromioclavicular capsule as a restraint to posterior translation of the clavicle: a biomechanical analysis.

Excessive posterior translation of the residual clavicle after distal clavicle resection can be associated with significant postoperative pain. Although the acromioclavicular capsule has been identified as the primary restraint to translation of the clavicle along this axis, the individual contributions of the anterior, posterior, superior, and inferior components of the capsular ligament have not been established. The purpose of this study was to define the relative roles of the individual acromioclavicular capsular ligaments in preventing posterior translation of the distal clavicle in normal acromioclavicular joints in a human cadaver model. Six fresh-frozen human cadaveric acromioclavicular joints were mounted on a specially designed apparatus which, when attached to a standard servohydraulic materials testing device, allowed translation of the distal clavicle along the anteroposterior axis of the acromioclavicular joint (i.e., parallel to the articular surface). Resistance to posterior displacement was measured for standardized displacements in the normal specimens and after serial sectioning of each of the acromioclavicular ligaments was performed. Sectioning of the anterior and inferior capsular ligaments had no significant effect on posterior translation at the 5% significance level. However, sectioning of the superior and posterior ligaments had statistically significant effects (P < .05). These capsular structures contributed 56% +/- 23% (+/- SEM) and 25% +/- 16%, respectively, of the force required to achieve a given posterior displacement. To avoid excessive posterior translation of the clavicle after distal clavicle excision, surgical techniques that spare the posterior and superior acromioclavicular capsular ligaments should be used.

Rotator cuff tendinosis in an animal model: Role of extrinsic and overuse factors

AbstractThe rat shoulder animal model has been used previously to study the role of intrinsic injury (modeled as an acute insult to the tendon), extrinsic injury (modeled as external subacromial impingement), and overuse factors on rotator cuff tendinosis. These studies demonstrated that it is possible to produce rotator cuff tendinosis with any one of these factors in isolation. The current study uses the rat shoulder model to study the roles of extrinsic compression, overuse, and overuse in combination with extrinsic compression, on the development of rotator cuff tendinosis. The results of this study demonstrate that the injury created by overuse plus extrinsic compression is greater than the injuries created by overuse or extrinsic compression alone, particularly when important biomechanical variables are considered. While ineffective in causing a change in supraspinatus tendon properties in animals with normal cage activity, extrinsic compression had a significant and dramatic effect when it was combined with overuse activity. Without an additional factor, such as overhead activity, the extrinsic compression alone may be insufficient to cause tendinosis. The results of the present study support the role of multiple factors in the etiology of some rotator cuff injuries.

Postoperative assessment of shoulder function: a prospective study of full-thickness rotator cuff tears.

Forty patients underwent surgery by a single surgeon for chronic, symptomatic, full-thickness rotator cuff defects. The study evaluated preoperative and intraoperative factors that influence postoperative outcome. The study also correlated objective measures of shoulder function with postoperative symptoms, patient satisfaction, and disability. Follow-up history and physical examination and strength measurements were performed at 2 years after surgery by three independent observers. There were 88% good or excellent results. Postscores correlated most closely with preoperative tear size. Postoperative Constant scores also correlated significantly with the patients subjective rating of the end result. Preoperative cuff tear size also correlated with the presence of postoperative fatigue symptoms and objective measures of shoulder strength. Preoperative cuff tear size strongly correlated with other prognostic factors including the quality of the tendon tissue, the difficulty for tendon mobilization, and the presence of a rupture of the long head of the biceps. Together these factors adversely affect postoperative function, patient satisfaction, and overall shoulder score. Neither premorbid activity level nor the presence of a workers compensation claim adversely affected the postoperative Constant score. The premorbid activity level significantly influenced the postoperative disability rating and the ability to return to work. All patients who were gainfully employed before surgery returned to employment after surgery, although in some patients at a lesser activity level.