Frank A. Cordasco

Propionibacterium acnes infection after shoulder arthroplasty: a diagnostic challenge.

HYPOTHESIS This study reviewed a series of patients diagnosed with Propionibacterium acnes infection after shoulder arthroplasty in order to describe its clinical presentation, the means of diagnosis, and provide options for treatment. MATERIALS AND METHODS From 2002 to 2006, 11 patients diagnosed with P acnes infection after shoulder arthroplasty were retrospectively reviewed and analyzed for (1) clinical diagnosis; (2) laboratory data, including white blood cell count, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP); (3) fever; (4) number of days for laboratory growth of P acnes; (5) organism sensitivities; (6) antibiotic regimen and length of treatment; and (7) surgical management. Infection was diagnosed by 2 positive cultures. RESULTS Five patients had an initial diagnosis of infection and underwent implant removal, placement of an antibiotic spacer, and staged reimplantation after a course of intravenous antibiotics. In the remaining 6 patients, surgical treatment varied according to the clinical diagnosis. When infection was recognized by intraoperative cultures, antibiotics were initiated. The average initial ESR and CRP values were 33 mm/h and 2 mg/dL, respectively. The average number of days from collection to a positive culture was 9. All cultures were sensitive to penicillin and clindamycin and universally resistant to metronidazole. DISCUSSION Prosthetic joint infection secondary to P acnes is relatively rare; yet, when present, is an important cause of clinical implant failure. Successful treatment is hampered because clinical findings may be subtle, many of the traditional signs of infection are not present, and cultures may not be positive for as long as 2 weeks.

Biomechanics of massive rotator cuff tears: implications for treatment.

BACKGROUND Some individuals with massive rotator cuff tears maintain active shoulder abduction, and some maintain good postoperative active range of motion despite high rates of repeat tears after repair. We devised a biomechanical rationale for these observations and measured the increases in residual muscle forces necessary to maintain active shoulder motion with rotator cuff tears of various sizes. METHODS A custom cadaver shoulder controller utilizing position and orientation closed-loop feedback control was used. Six cadaver glenohumeral joint specimens were tested in open-chain scapular plane abduction with equivalent upper extremity weight. The shoulder controller limited superior translation of the humeral head to 3.0 mm while maintaining neutral axial rotation by automatically controlling individual rotator cuff forces. Three-dimensional position and orientation and rotator cuff and deltoid force vectors were recorded. Specimens were tested with an intact rotator cuff and with 6, 7, and 8-cm tears. RESULTS All six specimens achieved full abduction with <or=3.0 mm of superior translation of the humeral head for all rotator cuff tear sizes. The effect of rotator cuff tear was significant for all tear sizes (p < 0.01). Compared with the intact condition, the subscapularis force requirements for the 6, 7, and 8-cm tears were increased by 30%, 44%, and 85%, respectively. For the combined infraspinatus and teres minor, the forces were increased by 32%, 45%, and 86%, respectively. The maximum deltoid force for the simulated tear condition never exceeded the deltoid force required at maximum abduction for the intact condition. However, between 10 degrees and 45 degrees of abduction, the average deltoid force requirement increased 22%, 28%, and 45% for the three tear sizes. CONCLUSIONS In the presence of a massive rotator cuff tear, stable glenohumeral abduction without excessive superior humeral head translation requires significantly higher forces in the remaining intact portion of the rotator cuff. These force increases are within the physiologic range of rotator cuff muscles for 6-cm tears and most 7-cm tears. Increases in deltoid force requirements occur in early abduction; however, greater relative increases are required of the rotator cuff, especially in the presence of larger rotator cuff tears.

Measurement of shoulder activity level.

There are many measurement tools for assessing patients’ shoulder symptoms (pain) and function (what patients can do), but they do not measure activity (how often a patient engages in activity). This is relevant because activity level can have an important impact on a patient’s outcome. Our goal was to develop a short, easy to administer measure of shoulder activity which could be used to predict outcome of shoulder disorders. The activity scale was developed using established principles: item generation, item reduction, pretesting, and reliability and validity testing. The activity rating is a numerical sum of scores for five activities rated on a five-point frequency scale from never performed (0 points) to daily (4 points). Patients were scored on the following criteria: carrying an object 8 lb or heavier by hand, handling objects overhead, weight training with arms, swinging motion (ie, hitting tennis or golf ball), and lifting objects 25 lb or heavier. Two additional multiple choice questions provide a score assessing participation in contact and overhead sports. The activity scale showed excellent reliability and construct validity. It can be completed quickly and used in conjunction with patient-based measures of shoulder outcome to define patient populations for cohort studies, and to assess activity level as a prognostic factor in patients with shoulder disorders. Level of Evidence: Prognostic study, Level I. See the Guidelines for Authors for a complete description of levels of evidence.

Results of Revision Anterior Cruciate Ligament Surgery

Background Revision anterior cruciate ligament surgery remains challenging. Purpose To analyze the authors’ experience with revision anterior cruciate ligament surgery and determine the association between stability and functional results. Study Design Case series; Level of evidence, 4. Methods Between 1991 and 2002, 95 of 102 patients who underwent revision anterior cruciate ligament reconstruction at the authors’ institution met the criteria for inclusion in the study. Of those, the 63 (66%) who returned for complete clinical and radiologic evaluation (mean follow-up, 72.7 months) formed the study group. Subjective evaluation focused on return to sports, arthritic symptoms, and subjective International Knee Documentation Committee criteria. Clinical evaluation included examination, KT-1000 arthrometer and functional testing, and radiographic analysis of alignment and arthritis. Results Based on International Knee Documentation Committee subjective scores and return to sports, results were rated as excellent/good in 45 patients (71%), fair in 6 (10%), and poor in 12 (19%). A grade IA or IIA Lachman and a KT-1000 arthrometer side-to-side difference of <3 mm (32/63 patients) was associated with a good/excellent result (P < .05). The mechanical axis was midline in 78% (49/63 patients). Radiographic arthritis (16 patients, 25%) was associated with duration of instability after primary failure (P < .03). Return to sports occurred in 59% (37/63 patients). Sixteen patients (25%) required a second revision surgery. Conclusion Revision anterior cruciate ligament surgery allowed approximately 60% of patients to go back to sports, most of them at lower levels than their prerevision function. Instrumented laxity of <3 mm was associated with a better result. Radiographic arthritis was associated with duration of instability symptoms after primary failure. Patients who undergo revision anterior cruciate ligament surgery should be counseled as to the expected outcome and cautioned that this procedure probably represents a salvage situation and may not allow them to return to their desired levels of function.

Anterior glenohumeral joint dislocations.

The glenohumeral joint is the most mobile articulation in the body and the most commonly dislocated diarthroidal joint. Anterior dislocation is by far the most common direction and can lead to instability of the glenohumeral joint, which ranges from subtle increased laxity to recurrent dislocation. Overtime, understanding of anterior shoulder dislocations and the resulting instability has improved. Likewise, significant advances in arthroscopic equipment have allowed use of the arthroscope to address anatomically the various lesions that cause instability. This article reviews the anatomy, pathophysiology, clinical evaluation, and treatment of anterior shoulder instability.

Deep vein thrombosis after reconstructive shoulder arthroplasty: a prospective observational study.

This clinical study was performed to document the prevalence of deep vein thrombosis (DVT) after prosthetic shoulder replacement surgery. We prospectively followed 100 consecutive shoulder arthroplasty procedures (total shoulder replacement in 73 and hemiarthroplasty in 27) in 44 male and 56 female patients for 12 weeks (mean age, 67 years; range, 17-88 years). Risk factors for venous thromboembolic disease were assessed preoperatively and postoperatively. A 4-limb surveillance color flow Doppler ultrasound was performed at 2 days (100 patients) and 12 weeks (50 patients randomly selected) after surgery, and the presence and location of DVT were recorded. Postoperative symptomatic or fatal pulmonary emboli (PE) were also recorded. The overall prevalence of DVT was 13.0%, consisting of 13 DVTs in 12 patients. These included 6 ipsilateral and no contralateral upper extremity DVTs and 5 ipsilateral and 2 contralateral lower extremity DVTs. The prevalence of DVT was 10.0% (10/100) at day 2 after surgery and 6.0% (3/50) at week 12 after surgery. The incidence of symptomatic nonfatal PE was 2.0% (2/100), and that of fatal PE was 1.0% (1/100). Risk factors associated with venous thromboembolic disease did not reach statistical significance because of the small study population sample size. At our institution, the prevalence of DVT after reconstructive shoulder arthroplasty was 13.0%, a rate comparable to that after hip arthroplasty (10.3%) but lower than that after knee arthroplasty (27.2%). Shoulder arthroplasty surgeons should be aware of the potential risk of perioperative thromboembolic complications in both the acute and subacute postoperative periods.

Humeral component retroversion in reverse total shoulder arthroplasty: a biomechanical study

BACKGROUND Reverse total shoulder arthroplasty offers pain relief and functional improvement for patients with rotator cuff-deficient shoulders. The purpose of this study was to determine the optimal amount of humeral retroversion for this prosthesis. MATERIALS AND METHODS Six cadaveric shoulders underwent computed tomography (CT) imaging and were then dissected of soft tissues, except for their tendinous attachments. A reverse total shoulder arthroplasty was implanted in 0°, 20°, 30°, and 40° of retroversion, and the shoulders were mounted on a simulator to determine the muscle forces required to achieve 30° and 60° of scaption. CT images were converted into 3-dimensional models, and the amount of internal and external rotation was determined with computer modeling at various scaption angles. RESULTS No differences were found in the forces required for 30° or 60° of scaption for any muscle, at any retroversion. With increasing retroversion, more impingement-free external rotation was obtained, with a concomitant decrease in the amount of internal rotation. Above 60°, the humerus was allowed to rotate around the glenosphere unencumbered. CONCLUSIONS Increasing retroversion did not affect the muscle force requirements for scaption across the shoulder. Placing the humeral component in 0° to 20° of retroversion allows maximum internal rotation with the arm at the side, a movement that is required for daily activities. This limits external rotation with the arm at the side, but has no effect on external rotation with the arm elevated.

Magnetic Resonance Imaging of Adhesive Capsulitis: Correlation with Clinical Staging

The purpose of this study was to evaluate non-contrast magnetic resonance imaging (MRI) findings of adhesive capsulitis and correlate them with clinical stages of adhesive capsulitis. This will hopefully define a role for shoulder MR imaging in the diagnosis of adhesive capsulitis as well as in potentially directing appropriate treatment. Forty-seven consecutive non-contrast magnetic resonance imaging examinations of 46 patients with a clinical diagnosis of adhesive capsulitis were retrospectively reviewed and correlated with clinical staging. Specific MRI criteria correlated with the clinical stage of adhesive capsulitis, including the thickness and signal intensity of the joint capsule and synovium as well as the presence and severity of scarring in the rotator interval. Routine MRI of the shoulder without intraarticular administration of gadolinium can be used to diagnose all stages of adhesive capsulitis, including stage 1, where findings may be subtle on clinical examination. We believe that future studies assessing the role of MRI in guiding the initiation of appropriate treatment should be undertaken.

Arthroscopic Rotator Cuff Repair Prospective Evaluation With Sequential Ultrasonography

Background Recent studies have demonstrated predictable healing after arthroscopic rotator cuff repair at a single time point, but few studies have evaluated tendon healing over time. Hypothesis Rotator cuff tears that are intact on ultrasound at 1 time point will remain intact, and clinical results will improve regardless of healing status. Study Design Cohort study; Level of evidence, 3. Methods The Arthroscopic Rotator Cuff Registry was established to determine the effectiveness of arthroscopic rotator cuff repair with clinical outcomes using the American Shoulder and Elbow Surgeons score and ultrasound at 1 and 2 years, postoperatively. Patients were assigned to 1 of 3 groups based on ultrasound appearance: group 1, rotator cuff tendon intact at 1 and 2 years (n = 63); group 2, rotator cuff tendon defect at 1 and 2 years (n = 23); group 3, rotator cuff tendon defect at 1 year but no defect at 2 years (n = 7). Results The ultrasound appearance was consistent at 1 and 2 years for 86 of the 93 patients (92.5%). The patients in group 1 had a significantly lower mean age (57.8 ± 9.8 years) than the patients of group 2 (63.6 ± 8.6 years; P = .04). Group 2 had a significantly greater rotator cuff tear size (4.36 ± 1.6 cm) than group 1 (2.84 ± 1.1 cm; P = .00025). Each group had a significant improvement in American Shoulder and Elbow Surgeons scores from baseline to 2-year follow-up. Conclusion All intact rotator cuff tendons at 1 year remained intact at 2 years. A small group of patients with postoperative imaging did not appear healed by ultrasound at 1 year but did so at 2 years. Patients demonstrated improvement in American Shoulder and Elbow Surgeons shoulder scores, range of motion, and strength, regardless of tendon healing status on ultrasound.

Ultrasound diagnosis of chondrocalcinosis in the knee.

The radiographic diagnosis of calcium pyrophosphate dihydrate (CPPD) deposition disease is usually made by observing calcifications in the articular cartilage of large joints or, in the knee, noting calcification in the menisci. Sonography is useful in evaluating the patellofemoral joint, including the trochlear cartilage, which is often difficult to image adequately on conventional radiographs, as true tangential views of the patellofemoral joint may be difficult to obtain. We describe a case of sonographic detection of cartilage calcification in the trochlea of the knee which was radiographically occult.