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1.  What Are Risk Factors for Intraoperative Humerus Fractures During Revision Reverse Shoulder Arthroplasty and Do They Influence Outcomes? 
With the increase in shoulder arthroplasty rates, the number of perioperative complications, such as periprosthetic fractures, continues to be a rise; however, the risk factors and incidence of intraoperative complications, such as fractures, during revision reverse shoulder arthroplasty are not well established.
We evaluated patients receiving a reverse shoulder arthroplasty to determine (1) the frequency and characteristics of intraoperative humerus fractures, (2) the risk factors for fracture, (3) the complications associated with treatment of fractures, and (4) clinical and functional outcomes after treatment.
Using one institution’s total joint registry, we performed a retrospective analysis of medical records of 224 patients (230 shoulders) who underwent revision surgery to reverse shoulder arthroplasty, from 2005 to 2012, for failed total shoulder arthroplasty. Reverse shoulder arthroplasty was used when there was a deficient rotator cuff, prior instability, or deficient glenoid bone stock. Intraoperative periprosthetic humerus fractures occurred in 36 shoulders (16%) (36 patients). The clinical outcome analysis included 29 patients with a minimum 2-year clinical followup (mean followup, 3.1 years; range, 2.0−6.3 years). The control group consisted of 188 patients (194 shoulders), and it was used for risk-factor calculation; whereas only 150 patients (154 shoulders) in the control group had a minimum 2-year followup, and thus only 150 patients (154 shoulders) made up the comparators (controls) for outcome-analysis comparisons. Risk factors were assessed using univariate analysis with odds ratios (OR), whereas implant survival and complications were assessed using the Kaplan-Meier method.
Three displaced and 33 nondisplaced fractures occurred during revision reverse total shoulder arthroplasties. Most of the fractures (81%) occurred during component removal of cemented (n = 11) and cementless (n = 25) components. Intraoperative fractures only were treated with stabilization of the prosthetic stem in 28 patients, while adjunctive internal fixation was used in eight patients. Risk of intraoperative periprosthetic fractures was increased by factors including female sex (n =18 women; OR, 2.41; range, 1.11−5.68; p = 0.03); history of instability (n = 27; OR, 2.65; range, 1.18−5.93; p = 0.02); and prior hemiarthroplasty (n = 22; OR, 2.34; range, 1.13−4.84; p = 0.03). There were two postoperative fractures in patients who had an intraoperative fracture and both were treated nonoperatively. Overall, three (8%) revision procedures were performed in patients with intraoperative fractures, with 2- and 5-year survivorship estimates of 94% and 85%, respectively, compared with 89% and 84%, respectively for patients without an intraoperative fracture (p = 0.45). At latest followup, patients experienced good postoperative pain relief, improved shoulder abduction, and good American Shoulder and Elbow Surgeon and Simple Shoulder Test scores.
Intraoperative humeral fractures occur in approximately 16% of shoulders undergoing revision surgery. Fractures during revision reverse TSA are not uncommon secondary to the risks of component removal in revision surgery and poor remaining bone stock. The risk seems to be greatest for female patients, patients with instability, and patients who have undergone previous hemiarthroplasties. Intraoperative humeral fractures should be approached in a systematic way to achieve anatomic reduction and stable fixation. When properly stabilized, these fractures appear not to substantially influence overall final outcome. This study provides a foundation for future investigation of methods to reduce the risk for intraoperative humeral fractures attributable to reverse revision TSA.
Level of Evidence
Level III, therapeutic study.
PMCID: PMC4562920  PMID: 26162412
2.  Revision of failed humeral head resurfacing arthroplasty 
The purpose of this study is to assess the outcomes of a consecutive series of patients who underwent revision surgery after humeral head resurfacing (HHR). Our joint registry was queried for all patients who underwent revision arthroplasty for failed HHR at our institution from 2005 to 2010. Eleven consecutive patients (average age 54 years; range 38-69 years) that underwent revision of 11 resurfacing arthroplasties were identified. The primary indication for resurfacing had been osteoarthritis in six, glenoid dysplasia in two, a chondral lesion in two, and postinstability arthropathy in one patient. The indication for revision was pain in 10 and infection in one patient. Seven patients had undergone an average of 1.9 surgeries prior to resurfacing (range 1-3).
Materials and Methods:
All patients were revised to stemmed arthroplasties, including one hemiarthroplasty, two reverse, and eight anatomic total shoulder arthroplasties at a mean 33 months after primary resurfacing (range 10-131 months). A deltopectoral approach was used in seven patients; four patients required an anteromedial approach due to severe scarring. Subscapularis attenuation was found in four cases, two of which required reverse total shoulder arthroplasty. Bone grafting was required in one glenoid and three humeri.
At a mean follow-up of 3.5 years (range 1.6-6.9 years), modified Neer score was rated as satisfactory in five patients and unsatisfactory in six. Abduction and external rotation improved from 73° to 88° (P = 0.32) and from 23° to 32° (P = 0.28) respectively. Reoperation was required in two patients, including one hematoma and one revision for instability.
Outcomes of revision of HHR arthroplasty in this cohort did not improve upon those reported for revision of stemmed humeral implants. A comparative study would be required to allow for definitive conclusions to be made.
PMCID: PMC4772412  PMID: 26980986
Humeral head resurfacing; revision; shoulder arthroplasty
3.  Clinical and radiographic factors influencing the results of revision rotator cuff repair 
Historically, results of open revision of rotator cuff repair have been mixed and often poor. We reviewed the outcomes of revision rotator cuff repair with a detailed analysis of clinical and radiographic risk factors in order to improve patient selection for this type of surgery.
Materials and Methods:
Thirty-six patients (37 shoulders) underwent first-time, open revision rotator cuff repair between 1995 and 2005. Average follow-up was 7.0 years (range 1-14.9 years). The tear size was small in 1 shoulder, medium in 8, large in 22 and massive in 6. Associations of 29 clinical and radiographic factors with the outcomes of pain, motion, and function were assessed.
Satisfactory outcome occurred in 22 shoulders (59%): An excellent result in 2, a good result in 7, and a fair result in 13. Unsatisfactory, poor results occurred in 15. Pain was substantially reduced in 25 (68%). Median pain scores decreased to five from a pre-operative eight (P = 0.002). Median motion did not change from pre-operative to post-operative. The chance of a satisfactory outcome and improved post-operative motion were associated with males, greater pre-operative motion, increased acromial humeral distance, the absence of glenohumeral arthritis, or a degenerative re-tear.
Revision rotator cuff repair, although a safe operation, with a low re-operative rate, has very mixed overall results. By knowing the factors associated with success, surgeons can better counsel patients and with this increased knowledge, consider alternative treatment choices.
PMCID: PMC3743029  PMID: 23960361
Factor analysis; revision; rotator cuff; shoulder
4.  Arthroscopy and the Dramatic Increase in Frequency of Anterior Acromioplasty from 1980 to 2005: An Epidemiologic Study 
The purpose of this study is to better understand the utilization of anterior acromioplasty over time – in the absence of rotator cuff repair, to examine the relationship to patient characteristics (age, sex) and types of rotator cuff pathology (inflammation or fibrosis, partial thickness tearing, full thickness tearing undergoing debridement), and to assess the utilization of arthroscopy in this procedure.
Using the resources of the Rochester Epidemiology Project, cataloging medical records of residents in Olmsted County, Minnesota, we identified 246 patients who underwent anterior acromioplasty between 1980 and 2005. It has previously been shown that rarely does a resident of Olmsted County undergo an orthopedic procedure at a facility outside the county.
The incidence of anterior acromioplasty increased over time (p<0.001) with the crude rate of 3.3 per 100,000 in 1980 to 1985 to 19.0 per 100,000 in 2000 to 2005. Sex, age, and types of rotator cuff pathology did not significantly change over the twenty-six year period. There was a dramatic shift from use of the open to the arthroscopic approach over this time period (p<0.001) and a decrease in the concomitant performance of distal clavicle resection (p<0.001).
The frequency of anterior acromioplasty has dramatically increased over time. Increasing knowledge about this syndrome, including better imaging, has facilitated patient treatment for a stable spectrum of rotator cuff pathology (inflammation or fibrosis, partial thickness tearing, full thickness tearing undergoing debridement), as has the application of endoscopic surgery.
PMCID: PMC3074176  PMID: 20691562
5.  Revision surgery following Total Shoulder Arthroplasty: Analysis of 2,588 shoulders over 3 decades (1976–2008) 
The Journal of bone and joint surgery. British volume  2011;93(11):10.1302/0301-620X.93B11.26938.
Our objective was to examine the revision rates and its predictors in patients undergoing Total Shoulder Arthroplasty (TSA). We used the prospectively collected data from the Mayo Clinic Total Joint Registry to examine the 5-, 10- and 20-year revision-free survival following TSA and its predictors. We examined patient characteristics (age, gender, BMI, comorbidity), implant fixation (cemented versus not), American Society of Anesthesiologists class, and underlying diagnosis. Univariate and multivariable adjusted hazard rates were calculated using Cox regression analyses. Two thousand two hundred seven patients underwent 2,588 TSAs. Mean age was 65 years with 53% women, and osteoarthritis was the underlying diagnosis in 63%. Two hundred twelve TSAs were revised during the follow-up. At 5-, 10- and 20- years, implant survival rates (95% confidence interval) were 94.2% (93.2%–95.3%), 90.2% (88.7%–91.7%) and 81.4% (78.4%–84.5%). In multivariable analyses, men had higher hazard ratio of revision, 1.72 (95% confidence interval, 1.28–2.31) (p<0.01), than women, and those with rotator cuff disease had hazard ratio of 3.99 (95% confidence interval, 1.91–8.36) (p<0.01), compared to patients with rheumatoid arthritis. We conclude that male gender and rotator cuff disease are independent risk factors for revision. Future studies are needed to understand the biological rationale for these differences.
PMCID: PMC3882033  PMID: 22058304
revision; total shoulder arthroplasty; gender; predictors
6.  Periprosthetic infections after total shoulder arthroplasty: a 33-year perspective 
To examine the rates and predictors of deep periprosthetic infections after primary total shoulder arthroplasty (TSA).
We used prospectively collected data on all primary TSA patients from 1976-2008 at Mayo Clinic Medical Center. We estimated survival free of deep periprosthetic infections after primary TSA using Kaplan-Meier survival. Univariate and multivariable Cox regression was used to assess the association of patient-related factors (age, gender, body mass index), comorbidity (Deyo-Charlson index), American Society of Anesthesiologists class, implant fixation, and underlying diagnosis with risk of infection.
A total of 2,207 patients, with a mean age of 65 years (SD, 12 years), 53% of whom were women, underwent 2,588 primary TSAs. Mean follow-up was 7 years (SD, 6 years), and the mean body mass index was 30 kg/m2 (SD, 6 kg/m2). The American Society of Anesthesiologists class was 1 or 2 in 61% of cases. Thirty-two confirmed deep periprosthetic infections occurred during follow-up. In earlier years, Staphylococcus predominated; in recent years, Propionibacterium acnes was almost as common. The 5-, 10-, and 20-year prosthetic infection–free rates were 99.3% (95% confidence interval [CI], 98.9-99.6), 98.5% (95% CI, 97.8-99.1), and 97.2% (95% CI, 96.0-98.4), respectively. On multivariable analysis, a male patient had a significantly higher risk of deep periprosthetic infection (hazard ratio, 2.67 [95% CI, 1.22-5.87]; P =.01) and older age was associated with lower risk (hazard ratio, 0.97 [95% CI, 0.95-1.00] per year; P =.05).
The periprosthetic infection rate was low at 20-year follow-up. Male gender and younger age were significant risk factors for deep periprosthetic infections after TSA. Future studies should investigate whether differences in bone morphology, medical comorbidity, or other factors are underlying these associations.
PMCID: PMC3586318  PMID: 22516570
Total shoulder arthroplasty; periprosthetic infections
7.  Peri-prosthetic Infections after Shoulder Hemiarthroplasty 
To examine the rates and predictors of deep peri-prosthetic infections following shoulder hemi-arthroplasty.
We used prospectively collected Institutional Registry data on all primary shoulder hemi-arthroplasty patients from 1976–2008. We estimated survival-free of deep peri-prosthetic infections using the Kaplan-Meier survival curves. Using univariate Cox regression analyses, we examined the association of patient-related factors (age, gender, body mass index (BMI)), comorbidity (Charlson index), ASA grade, underlying diagnosis and implant fixation with the risk of infection.
1,349 patients, with mean age 63 years (standard deviation, 16) with 63% women, underwent 1,431 primary shoulder hemi-arthroplasties. Mean follow-up was 8 years (standard deviation, 7 years). Fourteen deep peri-prosthetic infections occurred during the follow-up, confirmed by medical record review. Most common organisms were staphylococcus aureus, staphylococcus coagulase negative and Propionobacterium acnes, each accounting for 3 cases (21% each). The 5-, 10- and 20-year prosthetic infection-free rates (95% confidence interval) were 98.9% (98.3%, 99.5%), 98.7% (98.1%, 99.4%) and 98.7% (98.1%, 99.4%) respectively. None of the factors evaluated were significantly associated with risk of prosthetic infection after primary shoulder hemi-arthroplasty, except that an underlying diagnosis of trauma was associated with significantly higher hazard ratio of 3.18 (95% confidence interval, 1.06–9.56) of infection compared to all other diagnoses (p=0.04). A higher body mass index showed a non-statistical trend towards association with higher hazard (p=0.13).
The periprosthetic infection rate after shoulder hemi-arthroplasty was low, estimated at 1.3% at 20-year follow-up. An underlying diagnosis of trauma was associated with a higher risk of periprosthetic infection. These patients should be observed closely for development of infection.
PMCID: PMC3310339  PMID: 22154310
Shoulder hemiarthroplasty; humeral head replacement; infection; age
8.  Strontium-85 extraction during transcapillary passage in tibial bone 
Journal of applied physiology  1975;39(4):596-602.
Indicator dilution experiments were done to determine the extraction of 85Sr during a single passage through capillaries of the tibial diaphysis. Extraction was estimated by injection of 85SrCl2 and a nonpermeant, reference tracer, T-1824-labeled albumin, into the nutrient artery and recording of the effluent venous dilution curves (femoral vein). The mean (± SD) maximal instantaneous extraction was 0.53 ± 0.08 (N = 12). Net retention after 10 min, estimated from venous curves, was 0.41 ± 0.06 (N = 12), which appeared not substantially different from the retention estimated by direct isotope counting of the tibias for 85Sr, 0.35 ± 0.06 (N = 12). In a second set of experiments in intact animals, tibial 85Sr extraction after intravenous injection was apparently higher, 0.53 ± 0.28 (N = 15). Values of tibial diaphyseal blood flow, estimated from washout curves for iodoantipyrine after tibial nutrient artery injection, were 1.47 ± 0.63 ml/min per 100 g (N = 27). The extraction was not much diminished by higher flows. The estimates of permeability-surface area product (PS) for bone capillaries did increase with flow, suggesting recruitment of more capillaries at higher flows. PS values averaged 0.63 ± 0.29 (N = 12); we conclude that the capillary membrane is a primary barrier to the passage of 85Sr and presumably other small hydrophilic solutes.
PMCID: PMC3779862  PMID: 1104562
bone blood flow; instantaneous extraction; permeability-surface area products; 85Sr clearance; diffusible and nondiffusible tracers; bone capillary permeability; calcium uptake mechanisms in bone
9.  Ninety day mortality and its predictors after primary shoulder arthroplasty: an analysis of 4,019 patients from 1976-2008 
Examine 90-day postoperative mortality and its predictors following shoulder arthroplasty
We identified vital status of all adults who underwent primary shoulder arthroplasty (Total shoulder arthroplasty (TSA) or humeral head replacement (HHR)) at the Mayo Clinic from 1976-2008, using the prospectively collected information from Total Joint Registry. We used univariate logistic regression models to assess the association of gender, age, body mass index, American Society of Anesthesiologist (ASA) class, Deyo-Charlson comorbidity index, an underlying diagnosis and implant fixation with odds of 90-day mortality after TSA or HHR. Multivariable models additionally adjusted for the type of surgery (TSA versus HHR). Adjusted Odds ratio (OR) with 95% confidence interval (CI) were calculated.
Twenty-eight of the 3, 480 patient operated died within 90-days of shoulder arthroplasty (0.8%). In multivariable-adjusted analyses, the following factors were associated with significantly higher odds of 90-day mortality: higher Deyo-Charlson index (OR, 1.54; 95% CI:1.39, 1.70; p < 0.001); a diagnosis of tumor (OR, 16.2; 95%CI:7.1, 36.7); and ASA class III (OR, 3.57; 95% CI:1.29, 9.91; p = 0.01) or class IV (OR, 13.4; 95% CI:2.44, 73.86; p = 0.003). BMI ≥ 30 was associated with lower risk of 90-day mortality (OR, 0.25; 95% CI:0.08, 0.78). In univariate analyses, patients undergoing TSA had significantly lower 90-day mortality of 0.4% (8/2, 580) compared to 1% in HHR (20/1, 411) (odds ratio, 0.22 (95% CI: 0.10, 0.50); p = 0.0003).
90-day mortality following shoulder arthroplasty was low. An underlying diagnosis of tumor, higher comorbidity and higher ASA class were risk factors for higher 90-day mortality, while higher BMI was protective. Pre-operative comorbidity management may impact 90-day mortality following shoulder arthroplasty. A higher unadjusted mortality in patients undergoing TSA versus HHR may indicate the underlying differences in patients undergoing these procedures.
PMCID: PMC3206490  PMID: 21992475
mortality; shoulder arthroplasty; humeral head replacement; shoulder hemiarthroplasty
10.  Radiographic Stability of Ingrowth Humeral Stems in Total Shoulder Arthroplasty 
Cemented and uncemented stem types are available for TSA. An early uncemented stem designed for bone ingrowth had radiographic loosening of approximately 10% at intermediate followup (mean 4.6 years). Subsequent stem modifications included circumferential metaphyseal porous coating to enhance ingrowth and reduce loosening rates.
We asked whether the radiographic loosening rates would be lower after this design modification and whether the pain score and ROM would be improved.
Patients and Methods
We reviewed the medical records and radiographs of 76 patients undergoing primary TSA with circumferential metaphyseal porous-coated stems for osteoarthritis between 1995 and 2005. All patients had a complete standardized series of radiographs preoperatively, postoperatively, and at final followup. Humeral stems were evaluated for any radiolucent lines by zone, progression of lucencies, and shift in component position. The minimum radiographic followup was 25 months (average, 52 months; range, 25–90 months).
There were no radiolucencies seen on the initial postoperative radiographs. Five stems had 1-mm radiolucent lines in one to four of eight zones at final followup. One had a glenoid component judged at risk. None of the humeral components were judged at risk or loose or to have shifted. The pain scores and ROM improved postoperatively.
Proximally coated humeral stems for TSA showed few radiolucencies and no loosening at short- to midterm followup, reflecting an improvement over previous series. We now use these stems for primary TSAs and reserve cemented stems only when uncemented fixation is not possible owing to bony deficiency.
Level of Evidence
Level IV, case series. See Guidelines for Authors for a complete description of levels of evidence.
PMCID: PMC2895835  PMID: 20232183
11.  Hemiarthroplasty for Proximal Humerus Fractures in Patients with Parkinson’s Disease 
Parkinson’s disease is a relatively common problem in geriatric patients with an annual incidence rate of 20.5 per 100,000. These patients are at increased risk for falls and resultant fractures. Several reports suggest total shoulder arthroplasty in patients with fractures has a relatively high rate of complications. Whether hemiarthroplasty reduces the rate of complications or improves pain or function is not known.
We therefore determined the ROM, pain, complications, and rate of failure of hemiarthroplasty for management of proximal humerus fractures in patients with Parkinson’s disease.
Patients and Methods
We retrospectively reviewed all eight hemiarthroplasties in patients with Parkinson’s disease for fracture of the proximal humerus between 1978 and 2005. Seven patients (seven shoulders) had a minimum of 2 years followup (mean, 9.9 years; range, 2–16 years).
Postoperatively, the mean active abduction was 97°, mean external rotation was 38°, and internal rotation was a mean of being able to reach the level of the sacrum. The mean postoperative pain score was 2.5 points (on a scale of 1–5). There was a greater tuberosity nonunion in one patient and a superior malunion of the greater tuberosity in three patients. No patient had revision surgery.
The benefit of hemiarthroplasty for proximal humerus fractures in patients with Parkinson’s disease was marginal with three shoulders in seven patients having moderate to severe persistent pain and limited function postoperatively.
Level of Evidence
Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.
PMCID: PMC2881987  PMID: 20387015
12.  C-Reactive Protein, Erythrocyte Sedimentation Rate and Orthopedic Implant Infection 
PLoS ONE  2010;5(2):e9358.
C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) have been shown to be useful for diagnosis of prosthetic hip and knee infection. Little information is available on CRP and ESR in patients undergoing revision or resection of shoulder arthroplasties or spine implants.
We analyzed preoperative CRP and ESR in 636 subjects who underwent knee (n = 297), hip (n = 221) or shoulder (n = 64) arthroplasty, or spine implant (n = 54) removal. A standardized definition of orthopedic implant-associated infection was applied. Receiver operating curve analysis was used to determine ideal cutoff values for differentiating infected from non-infected cases. ESR was significantly different in subjects with aseptic failure infection of knee (median 11 and 53.5 mm/h, respectively, p = <0.0001) and hip (median 11 and 30 mm/h, respectively, p = <0.0001) arthroplasties and spine implants (median 10 and 48.5 mm/h, respectively, p = 0.0033), but not shoulder arthroplasties (median 10 and 9 mm/h, respectively, p = 0.9883). Optimized ESR cutoffs for knee, hip and shoulder arthroplasties and spine implants were 19, 13, 26, and 45 mm/h, respectively. Using these cutoffs, sensitivity and specificity to detect infection were 89 and 74% for knee, 82 and 60% for hip, and 32 and 93% for shoulder arthroplasties, and 57 and 90% for spine implants. CRP was significantly different in subjects with aseptic failure and infection of knee (median 4 and 51 mg/l, respectively, p<0.0001), hip (median 3 and 18 mg/l, respectively, p<0.0001), and shoulder (median 3 and 10 mg/l, respectively, p = 0.01) arthroplasties, and spine implants (median 3 and 20 mg/l, respectively, p = 0.0011). Optimized CRP cutoffs for knee, hip, and shoulder arthroplasties, and spine implants were 14.5, 10.3, 7, and 4.6 mg/l, respectively. Using these cutoffs, sensitivity and specificity to detect infection were 79 and 88% for knee, 74 and 79% for hip, and 63 and 73% for shoulder arthroplasties, and 79 and 68% for spine implants.
CRP and ESR have poor sensitivity for the diagnosis of shoulder implant infection. A CRP of 4.6 mg/l had a sensitivity of 79 and a specificity of 68% to detect infection of spine implants.
PMCID: PMC2825262  PMID: 20179760
13.  Microbiologic Diagnosis of Prosthetic Shoulder Infection by Use of Implant Sonication▿  
Journal of Clinical Microbiology  2009;47(6):1878-1884.
We recently described a sonication technique for the diagnosis of prosthetic knee and hip infections. We compared periprosthetic tissue culture to implant sonication followed by sonicate fluid culture for the diagnosis of prosthetic shoulder infection. One hundred thirty-six patients undergoing arthroplasty revision or resection were studied; 33 had definite prosthetic shoulder infections and 2 had probable prosthetic shoulder infections. Sonicate fluid culture was more sensitive than periprosthetic tissue culture for the detection of definite prosthetic shoulder infection (66.7 and 54.5%, respectively; P = 0.046). The specificities were similar (98.0% and 95.1%, respectively; P = 0.26). Propionibacterium acnes was the commonest species detected among culture-positive definite prosthetic shoulder infection cases by periprosthetic tissue culture (38.9%) and sonicate fluid culture (40.9%). All subjects from whom P. acnes was isolated from sonicate fluid were male. We conclude that sonicate fluid culture is useful for the diagnosis of prosthetic shoulder infection.
PMCID: PMC2691098  PMID: 19261785
14.  Infection Associated With Hematoma Formation After Shoulder Arthroplasty 
Hematoma formation requiring operative treatment after shoulder arthroplasty may be associated with higher patient morbidity. We therefore determined whether there was an association of hematoma formation requiring operative treatment with deep infection after shoulder arthroplasty. Between 1978 and 2006, we performed 4147 shoulder arthroplasties in 3643 patients. Of these, 12 shoulders (0.3%) underwent reoperation for hematoma formation. The mean time interval from arthroplasty to surgery for the hematoma was 7 days (range, 0.5–31 days). Among nine cases in which cultures were taken, six had positive cultures; the organisms included Propionibacterium acnes in three, Staphylococcus epidermidis in one, Streptococcus species in one, and Staphylococcus epidermidis with Peptostreptococcus in one. The minimum followup was 12 months (mean, 68 months; range, 12 to 294 months). Two of the 12 patients eventually underwent resection arthroplasty for deep infection. The Neer score was excellent in one, satisfactory in six, and unsatisfactory in five patients. The data suggest hematoma formation after shoulder arthroplasty is often accompanied by positive intraoperative cultures. The surgeon should be aware of the high rate of unsatisfactory results associated with this complication as well as the possibility of developing a deep infection requiring additional surgery.
Level of Evidence: Level IV, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.
PMCID: PMC2384030  PMID: 18421541
15.  Projection of the Glenoid Center Point Within the Glenoid Vault 
Correct identification of the center point of the glenoid surface guides glenoid component placement. It is unknown whether the center point on the glenoid surface corresponds to the center of the glenoid vault at the medial extent of the glenoid prosthesis. We reviewed 20 consecutive computed tomography scans obtained preoperatively in patients with primary osteoarthritis. A glenoid center point was chosen on the glenoid surface and then projected back into the glenoid vault along the scapular axis and perpendicular to glenoid inclination. The difference from the projection of the glenoid surface center point to the center point at a 1.5-cm depth into the glenoid vault was then measured. The mean deviation of the glenoid center point at a depth of 1.5 cm from the center point at the glenoid articular surface was 1.7 mm anterior and 3.9 mm inferior. The most common deviation of the center point of the glenoid vault at the projected medial limit of the glenoid prosthesis was slightly anterior and inferior to the center point on the glenoid surface. Identifying the center of the glenoid surface coupled with alignment of the glenoid prosthesis in neutral version and anatomic inclination provides a reliable means to guide placement of glenoid components.
PMCID: PMC2505216  PMID: 18264846
16.  Augmented Glenoid Component for Bone Deficiency in Shoulder Arthroplasty 
Asymmetric posterior glenoid wear caused by degenerative glenohumeral arthritis can be addressed by several techniques during total shoulder arthroplasty. The purpose of this study was to evaluate the midterm outcome of a posterior augmented glenoid component to determine the clinical and radiographic outcome, including complications and the need for revision surgery. Between 1995 and 1999, 13 patients (14 shoulders) underwent a shoulder arthroplasty with an augmented glenoid component to treat posterior glenoid bone deficiency. All 14 shoulders had advanced osteoarthritis. The minimum followup for these 13 patients was 2 years (mean, 5 years; range, 2–8 years). The mean age of these patients was 66 years at the time of surgery (range, 52–78 years). The mean active elevation was 160° (range, 120°–180°) and external rotation was 56° (range, 30°–90°). According to a modified Neer result rating system, 36% of patients had an excellent result, 50% a satisfactory result, and 14% an unsatisfactory result. Our results suggest patients undergoing total shoulder arthroplasty with an asymmetric glenoid component for osteoarthritis achieve satisfactory mid-term pain relief and improvement in function; however, instability is not always corrected. The advantage of this component seems marginal, and its use has been discontinued.
Level of Evidence: Level IV, retrospective review. See Guidelines for Authors for a complete description of levels of evidence.
PMCID: PMC2505205  PMID: 18196365
17.  Pulmonary embolism following rotator cuff repair 
Previous studies have provided data on the incidence of pulmonary embolism following shoulder arthroplasty and repair of fractures of the proximal humerus. However, there is no information on the risk of pulmonary embolism following the surgical management of rotator cuff tears.
We performed a review of 1176 patients who underwent operative procedures for rotator cuff tears between January 1st, 2001 and December 31st, 2005 to identify all patients who developed a symptomatic pulmonary embolism postoperatively.
Three patients developed pulmonary embolisms that were diagnosed with computed tomography angiography. The overall incidence was calculated to be 0.26%. None of the patients died as a result of the pulmonary embolism.
The data from this review indicates that the risk of pulmonary embolism following surgery for rotator cuff repair is low, but not nonexistent. The most common presenting symptoms of pulmonary embolism were chest pain, shortness of breath, and hypoxia. This study should raise surgeons' awareness about this possible complication following rotator cuff repair surgery.
PMCID: PMC2840827  PMID: 20300313
Pulmonary embolism; rotator cuff repair; shoulder surgery
18.  A biomechanical analysis of strength and motion following total shoulder arthroplasty 
The primary goal of total shoulder arthroplasty (TSA) has traditionally been pain relief and motion improvement. The literature contains multiple studies that have documented the restoration of motion and consistent pain relief following the procedure. However, there has been little attention placed on strength following TSA. Therefore, the purpose of this study was to determine in an objective manner whether strength and motion improve with shoulder arthroplasty and over what time course this may occur.
Materials and Methods:
Between April 2002 and January 2004, 15 patients who underwent TSA for osteoarthritis had biomechanical strength testing preoperatively, at 6 and 12 months postoperatively. The mean age at the time of TSA was 66 years (range, 52-82). None of the patients had full thickness rotator cuff tears at the time of surgery. Peak forces for shoulder flexion, extension, abduction, internal rotation and external rotation strength were recorded. In addition, patients had shoulder range of motion measurements performed.
Range of motion improved significantly with TSA from preoperative to 6 months postoperative: flexion 104° to 147° (P = 0.0034), abduction 86° to 145° (P = 0.0001), internal rotation 43° to 54° (P = 0.0475) and external rotation 25° to 50° (P = 0.0008). There was minimal improvement in range of motion from 6 to 12 months. In contrast, there continued to be improvements in strength from the 6 month to the 12 month postoperative time frame: extension 18.3 kg to 22.4 kg (P = 0.006), abduction 11.3 kg to 12.8 kg (0.0474) and external rotation 8.8 kg to 10.1 kg (P = 0.016). Despite these improvements, compared to normative values, there continued to be relative weakness of the shoulder following TSA.
The data from this study suggest that recovery of strength and motion follow different time frames after TSA. The results of this study may allow the surgeon to more accurately discuss with the patient over what time course strength and motion may return. In addition, this study raises important questions in regard to the current rehabilitation program used after shoulder arthroplasty and whether development of new protocols may improve the functional outcome from surgery.
Level of Evidence:
Level 2
PMCID: PMC3022140  PMID: 21264147
Biomechanics; motion; strength; total shoulder arthroplasty

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