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Background: Glenohumeral osteoarthritis may be associated with severe posterior glenoid bone loss and glenoid retroversion. Treatment with total shoulder arthroplasty and autologous bone graft obtained from the humeral head has been infrequently reported in the peer-reviewed literature. Methods: The clinical and radiographic results of primary total shoulder replacement with an all-polyethylene glenoid component and autologous humeral head graft augmentation performed by a single surgeon in thirteen consecutive patients were evaluated. Results: Twelve of the thirteen patients were followed for a minimum of two years (average, fifty-three months; range, twenty-six to 110 months). The average glenoid retroversion on preoperative computed tomography (CT) scans was 44° (range, 20° to 65°). Based on the Walch classification of pathologic glenoid morphology, nine glenoids were B2 and three were type C. All patients had an intact cuff at the time of surgery. At the time of the last follow up, ten of the twelve patients had graft incorporation without any resorbtion and two had minor bone graft resorption. Broken screws occurred in two of these ten cases. Two patients, both of whom required revision surgery, had failure of fixation and of graft incorporation; one of these failures was due to early postoperative trauma and the other, to Propionibacterium acnes infection. Conclusions: The early and midterm results of total shoulder arthroplasty with autogenous bone graft demonstrated substantial clinical and radiographic improvement in most cases. Level of Evidence: Therapeutic Leve IV. See Instructions for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

The article discusses the study in which eccentric loading and glenoid component retroversion shows as a significant mechanism that leads to glenoid component loosening. The study uses 66 shoulders as subjects that underwent total shoulder displacement with an all-polyethylene press-fit pegged glenoid component that was designed for osseous ingrowth for osteoarthritis treatment. Results shows that 30 percent of the 66 shoulders had osteolysis around the center peg.

The article reports a study which was conducted to measure the prevalence, timing, and magnitude of tendon retraction after rotator cuff repair. The results revealed that all rotator cuff tendon repairs retracted away from their position of initial fixation during the first year after surgery. All patients demonstrated some degree of medial tendon retraction after rotator cuff repair, whether or not they went on to form a recurrent tendon defect.

Background: Glenoid component malposition for anatomic shoulder replacement may result in complications. The purpose of this study was to define the efficacy of a new surgical method to place the glenoid component.Methods: Thirty-one patients were randomized for glenoid component placement with use of either novel three-dimensional computed tomographic scan planning software combined with patient-specific instrumentation (the glenoid positioning system group), or conventional computed tomographic scan, preoperative planning, and surgical technique, utilizing instruments provided by the implant manufacturer (the standard surgical group). The desired position of the component was determined preoperatively. Postoperatively, a computed tomographic scan was used to define and compare the actual implant location with the preoperative plan.Results: In the standard surgical group, the average preoperative glenoid retroversion was -11.3° (range, -39° to 17°). In the glenoid positioning system group, the average glenoid retroversion was -14.8° (range, -27° to 7°). When the standard surgical group was compared with the glenoid positioning system group, patient-specific instrumentation technology significantly decreased (p < 0.05) the average deviation of implant position for inclination and medial-lateral offset. Overall, the average deviation in version was 6.9° in the standard surgical group and 4.3° in the glenoid positioning system group. The average deviation in inclination was 11.6° in the standard surgical group and 2.9° in the glenoid positioning system group. The greatest benefit of patient-specific instrumentation was observed in patients with retroversion in excess of 16°; the average deviation was 10° in the standard surgical group and 1.2° in the glenoid positioning system group (p < 0.001). Preoperative planning and patient-specific instrumentation use resulted in a significant improvement in the selection and use of the optimal type of implant and a significant reduction in the frequency of malpositioned glenoid implants.Conclusions: Novel three-dimensional preoperative planning, coupled with patient and implant-specific instrumentation, allows the surgeon to better define the preoperative pathology, select the optimal implant design and location, and then accurately execute the plan at the time of surgery. [ABSTRACT FROM AUTHOR]

Background: Glenoid component malposition for anatomic shoulder replacement may result in complications. The purpose of this study was to define the efficacy of a new surgical method to place the glenoid component. Methods: Thirty-one patients were randomized for glenoid component placement with use of either novel three-dimensional computed tomographic scan planning software combined with patient-specific instrumentation (the glenoid positioning system group), or conventional computed tomographic scan, preoperative planning, and surgical technique, utilizing instruments provided by the implant manufacturer (the standard surgical group). The desired position of the component was determined preoperatively. Postoperatively, a computed tomographic scan was used to define and compare the actual implant location with the preoperative plan. Results: In the standard surgical group, the average preoperative glenoid retroversion was - 11.3° (range, -39° to 17°). In the glenoid positioning system group, the average glenoid retroversion was -14.8° (range, -27° to 7°). When the standard surgical group was compared with the glenoid positioning system group, patient-specific instrumentation technology significantly decreased (p < 0.05) the average deviation of implant position for inclination and medial-lateral offset. Overall, the average deviation in version was 6.9° in the standard surgical group and 4.3° in the glenoid positioning system group. The average deviation in inclination was 11.6° in the standard surgical group and 2.9° in the glenoid positioning system group. The greatest benefit of patient-specific instrumentation was observed in patients with retroversion in excess of 16°; the average deviation was 10° in the standard surgical group and 1.2° in the glenoid positioning system group (p < 0.001). Preoperative planning and patient-specific instrumentation use resulted in a significant improvement in the selection and use of the optimal type of implant and a significant reduction in the frequency of malpositioned glenoid implants. Conclusions: Novel three-dimensional preoperative planning, coupled with patient and implant-specific instrumentation, allows the surgeon to better define the preoperative pathology, select the optimal implant design and location, and then accurately execute the plan at the time of surgery. [ABSTRACT FROM AUTHOR]

Background: Scaffold devices are used to augment rotator cuff repairs in humans. While the strength of a novel poly-L-lactic acid-reinforced (human) fascia patch has been documented, it is unclear whether such patches will enhance the strength or likelihood of healing of rotator cuff repairs. Questions/purposes: In a canine shoulder model, we asked: Do tendon repairs augmented with a reinforced fascia patch have (1) increased biomechanical properties at Time 0 and (2) less tendon retraction and increased cross-sectional area and biomechanical properties after 12 weeks of healing compared to repairs without augmentation? (3) Do the biomechanical properties of tendon repairs reach normal values by 12 weeks of healing? And (4) is the host response associated with use of the reinforced fascia patch biocompatible? Methods: Eleven dogs underwent bilateral shoulder surgery with partial release and acute repair of the infraspinatus tendon, one shoulder with augmentation and one without augmentation. Repair retraction, cross-sectional area, biomechanical properties, and biocompatibility were assessed at 12 weeks. Results: At Time 0, the mean ± SD ultimate load of augmented repairs was 296 ± 130 N (46% ± 25%) more than nonaugmented repairs, with no difference in stiffness between groups. At 12 weeks, the ultimate load of augmented repairs averaged 192 ± 213 N (15% ± 16%) less than nonaugmented repairs, with no difference in stiffness between groups. At the tendon repair site at 12 weeks, the fascia patch showed a biocompatible host tissue response. Conclusions: The biomechanical properties of repairs augmented with a reinforced fascia patch demonstrated greater ultimate load at Time 0 than nonaugmented repairs but remained essentially unchanged after 12 weeks of healing, despite improvements in the ultimate load of nonaugmented controls in the same time frame. Clinical Relevance: Together with our previous work, these findings support the possibility that reinforced fascia patches would incorporate and provide (at least early) mechanical augmentation to rotator cuff repair in human patients. [ABSTRACT FROM AUTHOR]

Background: Loosening of the glenoid component continues to be the foremost cause of medium and long-term failure of shoulder replacements. The purpose of this study was to evaluate the clinical and radiographic results of a minimally cemented all-polyethylene pegged glenoid component designed for biologic fixation.Methods: Forty-four shoulders in forty-one patients with a mean age of sixty-six years underwent total shoulder arthroplasty with a pegged bone-ingrowth glenoid component. Outcome data included the American Shoulder and Elbow Surgeons questionnaire, the Simple Shoulder Test, and visual analog scales. A detailed radiographic analysis was performed by two board-certified musculoskeletal radiologists who were blinded to clinical and patient-reported outcomes. The radiographs were evaluated with regard to the presence of radiolucent lines at the bone-cement interface, implant seating, and the radiodensity between the flanges of the central peg.Results: The mean duration of clinical follow-up was four years and the mean duration of radiographic follow-up was three years. Twenty shoulders had perfect seating and radiolucency grades, thirty had increased radiodensity between the flanges of the central peg, and three demonstrated osteolysis. Radiodensity about the uncemented central peg at the time of the latest follow-up was positively associated with perfect seating and radiolucency grades on the initial postoperative radiographs (p = 0.03, Fisher exact test). The Simple Shoulder Test score, the American Shoulder and Elbow Surgeons score, and all visual analog scale scores had improved significantly (p < 0.01) at the time of the latest follow-up.Conclusions: Total shoulder arthroplasty with a minimally cemented, all-polyethylene, pegged glenoid implant can yield stable and durable fixation at short to medium-term follow-up (mean, four years). [ABSTRACT FROM AUTHOR]

Background: Loosening of the glenoid component continues to be the foremost cause of medium and long-term failure of shoulder replacements. The purpose of this study was to evaluate the clinical and radiographic results of a minimally cemented all-polyethylene pegged glenoid component designed for biologic fixation. Methods: Forty-four shoulders in forty-one patients with a mean age of sixty-six years underwent total shoulder arthroplasty with a pegged bone-ingrowth glenoid component. Outcome data included the American Shoulder and Elbow Surgeons questionnaire, the Simple Shoulder Test, and visual analog scales. A detailed radiographic analysis was performed by two board-certified musculoskeletal radiologists who were blinded to clinical and patient-reported outcomes. The radiographs were evaluated with regard to the presence of radiolucent lines at the bone-cement interface, implant seating, and the radiodensity between the flanges of the central peg. Results: The mean duration of clinical follow-up was four years and the mean duration of radiographic follow-up was three years. Twenty shoulders had perfect seating and radiolucency grades, thirty had increased radiodensity between the flanges of the central peg, and three demonstrated osteolysis. Radiodensity about the uncemented central peg at the time of the latest follow-up was positively associated with perfect seating and radiolucency grades on the initial postoperative radiographs (p = 0.03, Fisher exact test). The Simple Shoulder Test score, the American Shoulder and Elbow Surgeons score, and all visual analog scale scores had improved significantly (p < 0.01) at the time of the latest follow-up. Conclusions: Total shoulder arthroplasty with a minimally cemented, all-polyethylene, pegged glenoid implant can yield stable and durable fixation at short to medium-term follow-up (mean, four years). [ABSTRACT FROM AUTHOR]

The article presents the American Academy of Orthopaedic Surgeons (AAOS) Clinical Practice Guideline on Optimizing the Management of Rotator Cuff Problems. Topics include perioperative interventions, confounding factors for treatment options, and surgery to repair rotator cuff tears. It also notes post-operative treatment and rehabilitation.

Background: Two-stage reimplantation for prosthetic joint infection reportedly has the lowest risk for recurrent infection. Most studies to date have evaluated revision surgery for infection using an anatomic prosthetic. As compared with anatomic prostheses, reverse total shoulder arthroplasty is reported to have a higher rate of infection. Questions/purposes: We determined reinfection rates, functional improvement, types and rates of complications, and influence of rotator cuff tissue on function for two-stage reimplantation for prosthetic joint infection treated with reverse shoulder arthroplasty. Patients and Methods: We retrospectively reviewed 27 patients treated with a two-stage reimplantation for prosthetic shoulder infection using a uniform protocol for management of infection; of these, 17 had reverse shoulder arthroplasty at second-stage surgery. Types of organisms cultured, recurrence rates, complications, function, and radiographic followup were reviewed for all patients. Results: One of the 17 patients had recurrence of infection. The mean (± SD) Penn shoulder scores for patients treated with reverse shoulder arthroplasty improved from 24.9 ± 22.3 to 66.4 ± 20.8. The average motion at last followup was 123° ± 33° of forward flexion and 26° ± 8° of external rotation in patients treated with a reverse shoulder arthroplasty. The major complication rate was 35% in reverse shoulder arthroplasty, with five dislocations and one reinfection. There was no difference in final Penn score between patients with and without external rotation weakness. Conclusions: Shoulder function and pain improved in patients treated with a second-stage reimplantation of a reverse prosthesis and the reinfection rate was low. Level of Evidence: Level IV, case series. See Guidelines for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Summary: Mechanical forces influence homeostasis in virtually every tissue []. Tendon, constantly exposed to variable mechanical force, is an excellent model in which to study the conversion of mechanical stimuli into a biochemical response []. Here we show in a mouse model of acute tendon injury and in vitro that physical forces regulate the release of active transforming growth factor (TGF)-β from the extracellular matrix (ECM). The quantity of active TGF-β detected in tissue exposed to various levels of tensile loading correlates directly with the extent of physical forces. At physiological levels, mechanical forces maintain, through TGF-β/Smad2/3-mediated signaling, the expression of Scleraxis (Scx), a transcription factor specific for tenocytes and their progenitors. The gradual and temporary loss of tensile loading causes reversible loss of Scx expression, whereas sudden interruption, such as in transection tendon injury, destabilizes the structural organization of the ECM and leads to excessive release of active TGF-β and massive tenocyte death, which can be prevented by the TGF-β type I receptor inhibitor SD208. Our findings demonstrate a critical role for mechanical force in adult tendon homeostasis. Furthermore, this mechanism could translate physical force into biochemical signals in a much broader variety of tissues or systems in the body. [Copyright &y& Elsevier]

Outcomes after rotator cuff surgery are typically assessed with measures of strength, joint motion, or pain, but these measures do not provide a direct assessment of tissue function as healing progresses. To address this limitation, this manuscript describes biplane X-ray analysis as a technique for quantifying in vivo soft-tissue deformation. Tantalum beads were implanted in the humerus and infraspinatus tendon in a canine model of tendon injury and repair. Biplane X-ray images were acquired during treadmill trotting and tissue deformation was estimated from the three-dimensional bead positions. Changes over time were characterized by the mean, range, and normalized range (i.e., range/mean) of interbead distance. Intact tendon repair tissue demonstrated significant decreases over time in the mean ( p = 0.003), range ( p = 0.001), and normalized range ( p = 0.001) of interbead distance. Failed tendon repair tissue demonstrated significant decreases over time in the range ( p = 0.05) and normalized range ( p = 0.04) of interbead distance. In an uninjured control, differences over time in the interbead distance parameters were not detected. This approach is a promising technique for estimating changes over time in soft-tissue deformation. These preliminary data indicate appreciable differences between normal tendons, intact repairs, and failed repairs. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29:822-827 [ABSTRACT FROM AUTHOR]

Background: Despite advances in surgical treatment options, failure rates of rotator cuff repair have continued to range from 20% to 90%. Hence, there is a need for new repair strategies that provide effective mechanical reinforcement of rotator cuff repair as well as stimulate and enhance the intrinsic healing potential of the patient. The purpose of this study was to evaluate the extent to which augmentation of acute repair of rotator cuff tendons with a newly designed poly-L-lactide repair device would improve functional and biomechanical outcomes in a canine model. Methods: Eight adult, male mongrel dogs (25 to 30 kg) underwent bilateral shoulder surgery. One shoulder underwent tendon release and repair only, and the other was subjected to release and repair followed by augmentation with the repair device. At twelve weeks, tendon retraction, cross-sectional area, stiffness, and ultimate load of the repair site were measured. Augmented repairs underwent histologic assessment of biocompatibility. In addition, eight pairs of canine cadaver shoulders underwent infraspinatus injury and repair with and without device augmentation with use of identical surgical procedures and served as time-zero biomechanical controls. Eight unpaired, canine cadaver shoulders were included as normal biomechanical controls. Results: At time zero, repair augmentation significantly increased the ultimate load (23%) (p = 0.034) but not the stiffness of the canine infraspinatus tendon repair. At twelve weeks, the poly-L-lactide scaffold was observed to be histologically biocompatible, and augmented repairs demonstrated significantly less tendon retraction (p = 0.008) and significantly greater cross-sectional area (137%), stiffness (26%), and ultimate load (35%) than did repairs that had not been augmented (p < 0.001, p = 0.002, and p = 0.009, respectively). Conclusions: While limiting but not eliminating tendon repair retraction, the augmentation device provided a tendon-bone bridge and scaffold for host tissue deposition and ingrowth, resulting in improved biomechanical function of the repair at twelve weeks. Clinical Relevance: The augmentation device, applied in a similar manner as described in the present study, might offer a functional benefit to patients undergoing rotator cuff repair. [ABSTRACT FROM AUTHOR]

Background: While there have been numerous reports concerning glenohumeral arthrodesis for many indications, there is little available information specific to glenohumeral arthrodesis performed after failed prosthetic shoulder arthroplasty. The purpose of this study was to report the outcomes of glenohumeral arthrodesis in the setting of severe glenohumeral bone loss and deltoid muscle and rotator cuff insufficiency following failed prosthetic shoulder arthroplasty.Methods: We retrospectively reviewed clinical and radiographic data on seven consecutive patients treated with glenohumeral arthrodesis following a failed prosthetic shoulder arthroplasty between 1997 and 2004. The average duration of clinical follow-up was four years (range, 1.5 to eight years).Results: Five of the seven patients demonstrated an intact fusion at the time of the latest follow-up. Four of the seven patients had undergone additional bone-grafting procedures in an effort to obtain union. Two of these patients ultimately had a persistent nonunion despite the additional procedures for bone-grafting and revision of the fixation hardware. Overall, the average subjective clinical outcome score (Penn Shoulder Score) improved significantly from 17 points (range, 8 to 33 points) to 58 points (range, 31 to 77 points) (p = 0.008). The most common complication was delayed union requiring additional procedures for bone-grafting and revision of the fixation hardware.Conclusions: Treatment of a failed prosthetic shoulder arthroplasty with concomitant extensive glenohumeral bone loss and soft-tissue deficiencies is extremely challenging. The results of this study suggest that glenohumeral arthrodesis can yield satisfactory clinical outcomes. However, both the patient and the surgeon should be aware of the complex nature of this surgery and the frequent need for additional surgical procedures to obtain fusion. [ABSTRACT FROM AUTHOR]

Background: Arthritic changes to glenoid morphology can be difficult to fully characterize on both plain radiographs and conventional two-dimensional computer tomography images. We tested the hypothesis that three-dimensional imaging of the shoulder would increase inter-rater agreement for assessing the extent and location of glenoid bone loss and also would improve surgical planning for total shoulder arthroplasty. Methods: Four shoulder surgeons independently and retrospectively reviewed the preoperative computed tomography scans of twenty-four arthritic shoulders. The blinded images were evaluated with conventional two-dimensional imaging software and then later with novel three-dimensional imaging software. Measurements and preoperative judgments were made for each shoulder with use of each imaging modality and then were compared. The glenoid measurements were glenoid version and bone loss. The judgments were the zone of maximum glenoid bone loss, glenoid implant fit within the glenoid vault, and how to surgically address abnormal glenoid version and bone loss. Agreement between observers was evaluated with use of intraclass correlation coefficients and the weighted kappa coefficient (K), and we determined if surgical decisions changed with use of the three-dimensional data. Results: The average glenoid version (and standard deviation) measured - 17° ± 2.2° on the two-dimensional images and -19° ± 2.4° on the three-dimensional images (p < 0.05). The average posterior glenoid bone loss measured 9 ± 2.3 mm on the two-dimensional images and 7 ± 2 mm on the three-dimensional images (p < 0.05). The average anterior bone loss measured 1 mm on both the two-dimensional and the three-dimensional images. However, the intraclass correlation coefficients for anterior bone loss increased significantly with use of the three-dimensional data (from 0.36 to 0.70; p < 0.05). Observers were more likely to locate mid-anterior glenoid bone loss on the basis of the three-dimensional data (p < 0.05). The use of three-dimensional data provided greater agreement among observers with regard to the zone of glenoid bone loss, glenoid prosthetic fit, and surgical decision-making. Also, when the judgment of implant fit changed, observers more often determined that it would violate the vault walls on the basis of the three-dimensional data (p < 0.05). Conclusions: The use of three-dimensional imaging can increase inter-rater agreement for the analysis of glenoid morphology and preoperative planning. Important considerations such as the extent and location of glenoid bone loss and the likelihood of implant fit were influenced by the three-dimensional data. Clinical Relevance: We believe that these data support the concept that three-dimensional imaging techniques applied to the shoulder provide further information that may be useful to the surgeon during the planning of total shoulder arthroplasty. [ABSTRACT FROM AUTHOR]

Background: There is currently a severe shortage of clinician-scientists, who fill a vital role in musculoskeletal care. One way to address this shortage is to recruit more MD-PhD students into orthopaedics. We analyzed data from a national survey of MD-PhD students to assess this potential.Methods: A total of 868 students from thirteen MD-PhD training programs were requested to fill out a multiple-choice online survey concerning their education and future goals.Results: We achieved a response rate of 56.7% (492 of 868). Seven (1.4%) of the 492 respondents listed orthopaedics as their primary clinical interest, and thirty (6.1%) listed it as one of their three strongest clinical interests. Among the thirty respondents, seven (23%) were senior students, five (17%) were women, and none were minorities. In comparison, 33% of the 462 respondents in the nonorthopaedic cohort were women and 12.1% were a member of a minority group (p < 0.05). Among twenty-three students who had a secondary orthopaedic interest, only one-third had a primary surgical interest. Both the thirty with a strong clinical interest in orthopaedics and the others without a strong interest in orthopaedics showed similar intent on becoming physician-scientists (a score of 2.73 and 3.30, respectively) and an interest in an academic career (90.0% and 90.3%, respectively) (p > 0.05 for both). The orthopaedic group showed significantly greater interest in clinical care as a primary activity than did the nonorthopaedic group (63.3% compared with 30.7%; p < 0.0005). Eighty-seven percent of those in the orthopaedic group reported research as their most likely primary or secondary activity.Conclusions: This study suggests that there is a relatively strong interest in orthopaedic surgery (patient care and research) among MD-PhD students nationally, creating the potential to recruit approximately 100 new orthopaedic clinician-scientists every eight years (the average MD-PhD training period). Extrapolation indicates that there is the ability to double the number of orthopaedic clinician-scientists in the United States over the next fifty years. Therefore, efforts should be made to attract these students (especially women and those in underrepresented minority groups) to orthopaedic surgery. The study further suggests recruiting broadly-we should not be biased toward students late in training and just those with surgical interests. [ABSTRACT FROM AUTHOR]

Background: There is currently a severe shortage of clinician-scientists, who fill a vital role in musculoskeletal care. One way to address this shortage is to recruit more MD-PhD students into orthopaedics. We analyzed data from a national survey of MD-PhD students to assess this potential. Methods: A total of 868 students from thirteen MD-PhD training programs were requested to fill out a multiple-choice online survey concerning their education and future goals. Results: We achieved a response rate of 56.7% (492 of 868). Seven (1.4%) of the 492 respondents listed orthopaedics as their primary clinical interest, and thirty (6.1%) listed it as one of their three strongest clinical interests. Among the thirty respondents, seven (23%) were senior students, five (17%) were women, and none were minorities. In comparison, 33% of the 462 respondents in the nonorthopaedic cohort were women and 12.1% were a member of a minority group (p < 0.05). Among twenty-three students who had a secondary orthopaedic interest, only one-third had a primary surgical interest. Both the thirty with a strong clinical interest in orthopaedics and the others without a strong interest in orthopaedics showed similar intent on becoming physician-scientists (a score of 2.73 and 3.30, respectively) and an interest in an academic career (90.0% and 90.3%, respectively) (p> 0.05 for both). The orthopaedic group showed significantly greater interest in clinical care as a primary activity than did the nonorthopaedic group (63.3% compared with 30.7%; p <0.0005). Eighty-seven percent of those in the orthopaedic group reported research as their most likely primary or secondary activity. Conclusions: This study suggests that there is a relatively strong interest in orthopaedic surgery (patient care and research) among MD-PhD students nationally, creating the potential to recruit approximately 100 new orthopaedic clinician- scientists every eight years (the average MD-PhD training period). Extrapolation indicates that there is the ability to double the number of orthopaedic clinician-scientists in the United States over the next fifty years. Therefore, efforts should be made to attract these students (especially women and those in underrepresented minority groups) to orthopaedic surgery. The study further suggests recruiting broadly—we should not be biased toward students late in training and just those with surgical interests. [ABSTRACT FROM AUTHOR]

We present the design and development of an organic package that is compatible with fully released RF microelectromechanical systems (MEMS). The multilayer organic package consists of a liquid-crystal polymer film to provide near hermetic cavities for MEMS. The stack is further built up using organic thin-film polyimide. To demonstrate the organic package, we have designed and implemented a 2-bit true-time delay X-band phase shifter using commercially available microelectromechanical switches. The packaged phase shifter has a measured insertion loss of 2.45 ± 0.12 dB/bit at 10 GHz. The worst case phase variation of the phase shifter at 10 GHz is measured to less than 5°. We have also conducted temperature cycling (-65°C to 150 °C) and 85/85 to qualify the packaging structures. [ABSTRACT FROM AUTHOR]

Unlabelled: During revision total shoulder arthroplasty, bone grafting severe glenoid defects without concomitant reinsertion of a glenoid prosthesis may be the only viable reconstructive option. However, the fate of these grafts is unknown. We questioned the durability and subsidence of the graft and the associated clinical outcomes in patients who have this procedure. We retrospectively reviewed 11 patients with severe glenoid deficiencies from aseptic loosening of a glenoid component who underwent conversion of a total shoulder arthroplasty to a humeral head replacement and glenoid bone grafting. Large cavitary defects were grafted with either allograft cancellous chips or bulk structural allograft, depending on the presence or absence of glenoid vault wall defects, without prosthetic glenoid resurfacing. Clinical outcomes (Penn Shoulder Score, maximum 100 points) improved from 23 to 57 at a minimum 2-year followup (mean, 38 months; range, 24-73 months). However, we observed substantial graft subsidence in all patients, with eight of 11 patients having subsidence greater than 5 mm; the magnitude of graft resorption did not correlate with clinical outcome scores. Greater subsidence was seen with structural than cancellous chip allografts. Bone grafting large glenoid defects during revision shoulder arthroplasty can improve clinical outcome scores, but the substantial resorption of the graft material remains a concern. Level Of Evidence: Level III Prognostic study. [ABSTRACT FROM AUTHOR]

BACKGROUND: The purpose of this study was to evaluate the clinical results of latissimus dorsi tendon transfer in patients with an irreparable posterosuperior rotator cuff tear to help determine which patient and anatomic factors affect clinical outcome. METHODS: Fourteen patients with a latissimus dorsi tendon transfer were clinically evaluated with use of the PENN (University of Pennsylvania) shoulder score as well as with quantitative measurement of isometric muscle strength and the range of motion of both shoulders at a minimum of twenty-four months postoperatively. The anatomic results were evaluated with postoperative magnetic resonance imaging and electromyography. RESULTS: Nine patients were satisfied with the outcome, had significant clinical improvement, and reported that they would have the operation again under similar circumstances. The other five patients were dissatisfied with the result and had significantly worse PENN scores, active elevation, and objective measures of strength. Eight of the nine patients with a good clinical result were male, and four of the five with a poor result were female. Patients with a good clinical result had had significantly better preoperative function in active forward flexion and active external rotation compared with the patients with a poor result. The magnetic resonance imaging demonstrated healing of the tendon to the greater tuberosity in twelve patients and equivocal healing in two. There was no significant atrophy of any of the transferred muscles. Electromyography demonstrated clear activity in the transferred latissimus muscle during humeral adduction in all fourteen patients, some electrical activity with active forward elevation in only one patient, and some electrical activity with active external rotation in six of the nine patients with a good clinical result. None of the patients with a poor clinical result demonstrated electrical activity of the transferred muscle with active forward flexion or external rotation. CONCLUSIONS: Synchronous in-phase contraction of the transferred latissimus dorsi is a variable finding following the surgical treatment of irreparable posterosuperior rotator cuff tears, but when it is present it is associated with a better clinical result. Preoperative shoulder function and general strength influence the clinical result. Female patients with poor shoulder function and generalized muscle weakness prior to surgery have a greater likelihood of having a poor clinical result. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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), Tissue-Mend (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. Clinical Relevance: These data will help inform and guide the clinical community with regard to the appropriate use of commercially available extracellular matrix products for augmentation of rotator cuff tendon repair. Knowledge of the biophysical properties of these materials is fundamental to making an educated decision about whether a given matrix might provide mechanical augmentation and/or enhance the biology of tendon-to-bone healing. [ABSTRACT FROM AUTHOR]

Background: Evidence to justify the use of porcine small intestine submucosa to augment repairs of large and massive rotator cuff tears is based on favorable results found in studies of Achilles tendon and infraspinatus tendon repairs in canines. The purpose of this study was to determine the effectiveness of a small intestine submucosal patch to augment the repair of chronic two-tendon rotator cuff tears in humans.Methods: Thirty shoulders with a chronic two-tendon rotator cuff tear that was completely repairable with open surgery were randomized to be treated with either augmentation with porcine small intestine mucosa or no augmentation. All patients completed a PENN shoulder-score questionnaire preoperatively and at the time of the latest follow-up (at an average of fourteen months). Magnetic resonance imaging showed that nine shoulders had a large tear and twenty-one had a massive tear. All patients underwent a magnetic resonance imaging scan with intra-articular gadolinium one year after the repair to assess the status of the rotator cuff.Results: The rotator cuff healed in four of the fifteen shoulders in the augmentation group compared with nine of the fifteen in the control group (p = 0.11). The median postoperative PENN total score was 83 points in the augmentation group compared with 91 points in the control group (p = 0.07). Healing of the defects in both groups demonstrated a strong correlation with the patients' clinical scores. The median postoperative PENN total score was 96 points in the group with a healed repair and 81 points in the group with a failed repair (p = 0.007). The percentage change between the preoperative and postoperative patient satisfaction scores was 400% in the group with a healed repair, and 50% in the group with a failed repair (p = 0.04).Conclusions: Augmentation of the surgical repair of large and massive chronic rotator cuff tears with porcine small intestine submucosa did not improve the rate of tendon-healing or the clinical outcome scores. On the basis of these data, we do not recommend using porcine small intestine submucosa to augment repairs of massive chronic rotator cuff tears done with the surgical and postoperative procedures described in this study. [ABSTRACT FROM AUTHOR]

Background: Long-standing tears of the rotator cuff can lead to substantial and perhaps irreversible changes in the affected rotator cuff muscles. We developed a chronic rotator cuff tear in a canine model to investigate and quantify the time-related changes in passive mechanics, volume, and fat of the infraspinatus muscle. We hypothesized that infraspinatus muscle stiffness would increase, volume would decrease, and fat content would increase at twelve weeks following tendon detachment. Methods: The right infraspinatus tendon of eight adult mongrel dogs were surgically detached from the proximal part of the humerus. The uninvolved left shoulder served as a control. Muscle volume changes were quantified with use of magnetic resonance imaging. At twelve weeks, the passive mechanical properties of the chronically detached and control muscles were determined intraoperatively with use of a custom-designed device. Intramuscular fat was evaluated histologically at the time that the animals were killed. Results: After twelve weeks of detachment, the stiffness was significantly increased in the detached infraspinatus muscles relative to that in the controls (p < 0.0001). Magnetic resonance image analysis demonstrated that the detached muscle volumes decreased by an average of 32% in the first six weeks and remained constant thereafter. Intramuscular fat increased significantly in the detached muscles and to a greater extent in the lateral regions (p < 0.05). Conclusions: The chronically detached muscle is not merely a smaller version of the original muscle but, rather, a different muscle. The detached muscle becomes stiffer, and the passive loads required to repair it can become excessive. A significant reduction in muscle volume occurs within days to weeks following tendon detachment (p < 0.0001). The nonuniformity of changes in muscle fat suggests that fat content should be used cautiously as an indicator of muscle quality. Clinical Relevance: Clinically, chronic large rotator cuff tears are observed to have a qualitatively shorter and stiffer muscle-tendon unit than normal. We developed a chronic rotator cuff model to quantitatively investigate changes in the detached infraspinatus muscle. The passive mechanical properties of a chronically torn rotator cuff muscle-tendon unit may be a useful predictor of repairability and clinical outcome. [ABSTRACT FROM AUTHOR]

Background: This prospective multi-institutional study was designed to define the accuracy of ultrasonography, when performed in an orthopaedic surgeon's office, for the diagnosis of rotator cuff tears.Methods: An anatomic diagnosis and a treatment plan were made on the basis of office-based shoulder ultrasonography, physical examination, and radiographs for ninety-eight patients (ninety-nine shoulders) with a clinical diagnosis of a rotator-cuff-related problem. The results of the ultrasonographic studies were then compared with the results of magnetic resonance imaging and the operative findings.Results: Office-based ultrasonography led to the correct diagnosis for thirty-seven (88%) of forty-two shoulders with a full-thickness rotator cuff tear or both full and partial-thickness tears, twenty-six (70%) of thirty-seven shoulders with a partial-thickness rotator cuff tear only, and sixteen (80%) of twenty shoulders with normal tendons. In no case was the surgical approach (open or arthroscopic) that had been planned on the basis of the ultrasonography altered by the operative findings, but the operative finding of a full-thickness tear resulted in an arthroscopic cuff repair in four shoulders. Magnetic resonance imaging led to the correct diagnosis for forty (95%) of forty-two shoulders with a full-thickness rotator cuff tear or both full and partial-thickness rotator cuff tears, twenty-seven (73%) of thirty-seven shoulders with only a partial-thickness tear, and fifteen (75%) of twenty shoulders with normal tendons. There were no significant differences between magnetic resonance imaging and ultrasonography with regard to the correct identification of a full-thickness tear or its size. The sensitivity of ultrasonography for detecting tear size in the anterior-posterior dimension was 86% (95% confidence interval, 71% to 95%), and that of magnetic resonance imaging was 93% (95% confidence interval, 81% to 99%) (p = 0.26). The sensitivity of ultrasonography for detecting tear size in the medial-lateral dimension was 83% (95% confidence interval, 69% to 93%), and that of magnetic resonance imaging was 88% (95% confidence interval, 74% to 96%) (p = 0.41).Conclusions: A well-trained office staff and an experienced orthopaedic surgeon can effectively utilize ultrasonography, in conjunction with clinical examination and a review of shoulder radiographs, to accurately diagnose the extent of rotator cuff tears in patients suspected of having such tears. Errors in diagnosis made on the basis of ultrasonography most often consist of an inability to distinguish between partial and full-thickness tears that are approximately 1 cm in size. In this study, such errors did not significantly affect the planned surgical approach. [ABSTRACT FROM AUTHOR]

Background: Posterior glenoid bone loss is often seen in association with glenohumeral osteoarthritis. This posterior asymmetric wear can lead to retroversion of the glenoid component and posterior instability after total shoulder arthroplasty. Options for the treatment of this asymmetric wear include eccentric reaming of the so-called high side, bone-grafting, and/or anteverting the humeral component. Although anteverting the humeral component has been advocated by many, it has not been substantiated on the basis of biomechanical data. The purpose of the present study was to determine whether anteverting the humeral component increases the stability of a total shoulder replacement with a retroverted glenoid component.Methods: A total shoulder arthroplasty was performed in eight human cadaveric shoulders. The glenoid component was placed in 15 degrees of retroversion. Two humeral versions were tested for each specimen: anatomic version and 15 degrees of anteversion relative to anatomic version. The specimens were mounted supine in a custom fixture on a servohydraulic testing system. The humerus was translated posteriorly by one-half of the width of the glenoid. Three positions of humeral rotation were tested for each position of humeral version. Both the energy and the peak load were analyzed as measures of joint stability.Results: There was no significant difference in either energy or peak load between the tests performed with the humeral component in 15 degrees of anteversion and those performed with the component in anatomic version in any of the three rotational positions (p > 0.05).Conclusions: Although anteverting the humeral component during total shoulder arthroplasty to compensate for glenoid retroversion has been advocated, these data suggest that compensatory anteversion of the humeral component does not increase the stability of a shoulder replacement with a retroverted glenoid component. [ABSTRACT FROM AUTHOR]

Background: Posterior glenoid bone loss is often seen in association with glenohumeral osteoarthritis. This posterior asymmetric wear can lead to retroversion of the glenoid component and posterior instability after total shoulder arthroplasty. Options for the treatment of this asymmetric wear include eccentric reaming of the so-called high side, bone-grafting, and/or anteverting the humeral component. Although anteverting the humeral component has been advocated by many, it has not been substantiated on the basis of biomechanical data. The purpose of the present study was to determine whether anteverting the humeral component increases the stability of a total shoulder replacement with a retroverted glenoid component. Methods: A total shoulder arthroplasty was performed in eight human cadaveric shoulders. The glenoid component was placed in 15° of retroversion. Two humeral versions were tested for each specimen: anatomic version and 15° of anteversion relative to anatomic version. The specimens wore mounted supine in a custom fixture on a servohydraulic testing system. The humerus WaS translated posteriorly by one-half of the width of the glenoid. Three positions of humeral relation were tested for each position of humeral version. Both the energy and the peak load were analyzed as measures of joint stability. Results: There was no significant difference in either energy or peak load between the tests performed with the humeral component in 15° of anteversion and those performed with the component in anatomic version in any of the three rotational positions (p > 0.05). Conclusions: Although anteverting the humeral component during total shoulder arthroplasty to compensate for glenoid retroversion has been advocated, these data suggest that compensatory anteversion of the humeral compo- nent does not increase the stability of a shoulder replacement with a retroverted glenoid component. Clinical Relevance: These data further suggest that restoring a more neutral glenoid surface might be preferred when the surgeon is presented with posterior glenoid bone loss. [ABSTRACT FROM AUTHOR]

Presents a case of a nineteen-year old man with a history of intermittent clicking and pain in the left shoulder. Role of the rotator interval capsule in passive motion and stability of the shoulder; Contribution of humeral avulsion of glenohumeral ligaments to the cause of anterior shoulder instability; Use of magnetic resonance imaging during the analysis of the case.

Background: The floating shoulder (ipsilateral fractures of the clavicular shaft and the scapular neck) is thought to be an unstable injury pattern requiring operative stabilization in most instances. This recommendation has been made with little biomechanical data to support it. The purpose of this study was to determine the osseous and ligamentous contributions to the stability of experimentally created scapular neck fractures in a cadaver model. Methods: Standardized scapular neck fractures were made in twelve fresh-frozen human cadaveric shoulders. Each specimen was mounted in a specially designed testing apparatus and secured to a standard materials testing device. In group 1 (six shoulders), resistance to medial displacement was determined following sequential creation of an ipsilateral clavicular fracture, coracoacromial ligament disruption, and acromioclavicular capsular disruption. In group 2 (six shoulders), resistance to medial displacement was determined following sequential sectioning of the coracoacromial and coracoclavicular ligaments. Results: The average measured force for all specimens (groups 1 and 2) after scapular neck fracture was 183 ± 3.3 N (range, 166 to 203 N). The addition of a clavicular fracture (group 1) resulted in an average measured force of 128 ± 10.5 N (range, 83 to 153 N), which corresponds to only a 30% loss of stability. Subsequent sectioning of the coracoacromial and acromioclavicular capsular ligaments yielded an average force of 126 ± 9.1 N (range, 114 to 144 N), a 31% loss of stability, and 0 N, a complete loss of stability, respectively. Sectioning of the coracoacromial and coracoclavicular ligaments after scapular neck fracture (group 2) resulted in an average force of 103 ± 8.4 N (range, 89 to 118 N), a 44% loss of stability, and 0 N, a complete loss of stability, respectively. Conclusions: Ipsilateral fractures of the scapular neck and the clavicular shaft do not produce a floating... [ABSTRACT FROM AUTHOR]

Background: Rotator cuff repair is associated with good short or mid-term results, but to date there have been no long-term functional outcome studies demonstrating durability of results over time. In most long-term studies, the results have been compared with those of historical controls or with those of other, short-term follow-up studies. The purpose of the present prospective study was to evaluate short and long-term shoulder function after surgical repair in a single population of patients in order to follow changes over time. Methods: Thirty-three patients underwent surgery, performed by one surgeon, for the treatment of a chronic, symptomatic, full-thickness rotator cuff defect. Data were obtained from questionnaires and physical examinations preoperatively, at two years, and at ten years. Identical standardized pain and function questionnaires were used and clinical evaluation was performed in a consistent fashion at all time-periods. The activity level, Constant score, level of disability, shoulder function score, and patient's subjective rating of the outcome were determined at the time of the final follow-up and compared with the same parameters at the two-year follow-up examination in order to determine if early results change with time. Results: At the ten-year follow-up examination, there was no change in the raw Constant score determined at the two-year examination. When the Constant score was normalized for expected age-related changes, the percentage of patients who had a satisfactory result at ten years was even greater than the percentage at two years. Activity level decreased significantly over the time-period (p = 0.005). At the final follow-up examination, twelve patients worked at the same occupation as they had when the two-year examination was performed, two worked at a less strenuous occupation, and the remaining patients were retired. Only two patients retired because of problems related to the shoulder. The level of disability... [ABSTRACT FROM AUTHOR]

The article presents the results of research which was conducted in an effort to determine whether manipulation while under anesthesia conferred benefits to patients with frozen shoulder who had a home exercise program. Researchers found that the manipulation did not confer benefits to frozen shoulder patients.