A review of the New Zealand National Joint Registry to evaluate the survivorship and revision rates of Nexel and Coonrad-Morrey total elbow arthroplasty.

BACKGROUND: Total elbow arthroplasty (TEA) is an appropriate surgical treatment option for a variety of conditions ranging from inflammatory arthritis to trauma. Due to a high complication profile, implant companies have attempted to improve patient outcomes with evolving design mechanics and philosophy. However, the Nexel TEA prosthesis has been criticized for its unacceptably high revision rate by other research groups in the literature. The purpose of this study was to evaluate the survivorship and revision rates of the Nexel and Coonrad-Morrey total elbow arthroplasty implant systems in New Zealand. METHODS: Prospectively collected national joint registry data was used to compare the survival rates of these prostheses. Underlying diagnoses, reasons for revision, and patient demographics were all recorded. Statistical analysis included survival analysis using Kaplan-Meier curves and comparison between groups using independent t-tests. RESULTS: Over the 23-year study interval, the Nexel and Coonrad-Morrey prostheses showed similar survivorship and revision rates. The revision rates at 5 years were 7.3% for ZN and 4.5% for the Coonrad-Morrey cohorts. The average time to revision for those who are revised was 3.13 ± 1.74 years in the Nexel group and 4.93 ± 4.13 years in the Coonrad-Morrey population. CONCLUSION: Our study confirms a lower revision rate of the Nexel TEA compared to other studies in the literature. Additionally, the Nexel TEA implant performs comparably to its predecessor, the Coonrad-Morrey prosthesis in New Zealand. While it is difficult to explain the discrepancy in results with the study by Morrey et. al, future studies should focus on investigating postoperative radiographs and a deep analysis of the specific surgical technique used for this implant.

Does the stemless reverse arthroplasty compare to a conventional stemmed implant? Clinical and radiographic evaluation at 2 years' minimum follow-up.

BACKGROUND: Reverse shoulder arthroplasty (RSA) is a well-recognized treatment for many shoulder conditions, including rotator cuff arthropathy, primary glenohumeral joint arthritis, and rheumatoid arthritis, and can be used in both trauma and revision settings. Over the past 10 years, its popularity in New Zealand has been increasing, with a 6%-7% annual growth rate during this period. Stemless RSA designs have the following proposed advantages: They can preserve humeral bone stock, they can limit periprosthetic fractures, and they can be indicated in patients with abnormal diaphyseal humeral anatomy. To date, only 1 study has evaluated the outcomes of the Lima SMR Stemless implant. We present our data with an aim to report how the stemless reverse arthroplasty compares to a conventional stemmed implant. METHODS: We performed a retrospective review of a consecutive series of patients treated at a single institution between 2015 and 2020. The endpoint was defined as final follow-up at a minimum of 2 years. Patients were excluded from the final analysis if they underwent revision. Thirty-three patients were identified as having undergone stemless RSA. Thirty patients had patient-reported outcome measures and radiographs at a minimum of 2 years' follow-up. Three patients had undergone revision within 2 years. The same sample size of stemmed RSAs (n = 33) was selected for comparison. RESULTS: A total of 60 patients were included in the final analysis, of whom 30 underwent stemless RSA and 30 underwent stemmed RSA. The demographic characteristics of the 2 groups were comparable except age at operation, which showed a statistically significant difference (P = .001): 77 years (stemmed) vs. 65 years (stemless). The mean Oxford Shoulder Score was 40.1 in the stemless group vs. 40 in the stemmed group. The mean American Shoulder and Elbow Surgeons score was 72.9 in the stemless group vs. 79 in the stemmed group. Patient-reported outcome measures, pain scores, and satisfaction ratings were not statistically significantly different between the 2 groups. In terms of radiographic data, subsidence was observed in 2 patients in the stemless RSA group but the patients had no clinical symptoms. Also in the stemless RSA group, 1 patient had an acromial stress fracture and 1 patient had a superficial wound infection successfully treated with oral antibiotics. In terms of revisions in the stemless RSA group, 1 patient underwent revision owing to chronic infection, 1 underwent revision as a result of a periprosthetic fracture after a fall, and 1 underwent revision for gross instability. CONCLUSIONS: The early results of sRSA are promising, and the stemless implant shows similar outcomes to a conventional stemmed implant.

Short-term outcomes following 159 stemmed pyrolytic carbon shoulder hemiarthroplasties and how they compare with conventional hemiarthroplasties and total shoulder arthroplasties in patients younger than 60 years with osteoarthritis: results from the New Zealand National Joint Registry.

BACKGROUND: Despite the increasing use of pyrolytic carbon (pyrocarbon) hemiarthroplasty (PyCHA), clinical data reporting on its outcomes remain scarce. To date, no studies have compared the outcomes of stemmed PyCHA vs. conventional hemiarthroplasty (HA) and anatomic total shoulder arthroplasty (aTSA) in young patients. The primary aim of this study was to report on the outcomes of the first 159 stemmed PyCHAs performed in New Zealand. The secondary aim was to compare the outcomes of stemmed PyCHA vs. HA and aTSA in patients aged <60 years with osteoarthritis. We hypothesized that stemmed PyCHA would be associated with a low revision rate. We further hypothesized that in young patients, PyCHA would be associated with a lower revision rate and superior functional outcomes compared with HA and aTSA. METHODS: Data from the New Zealand National Joint Registry were used to identify patients who underwent PyCHA, HA, and aTSA between January 2000 and July 2022. The total number of revisions in the PyCHA group was determined, and the indications for surgery, reasons for revision, and types of revision were recorded. In patients aged <60 years, a matched-cohort analysis was performed comparing functional outcomes using the Oxford Shoulder Score (OSS). The revision rate of PyCHA was compared with that of HA and aTSA, calculated as revisions per 100 component-years. RESULTS: In total, 159 cases of stemmed PyCHA were performed and 5 cases underwent revision, resulting in an implant retention rate of 97%. Among patients aged <60 years with shoulder osteoarthritis, 48 underwent PyCHA compared with 150 who underwent HA and 550 who underwent aTSA. Patients treated with aTSA had a superior OSS compared with PyCHA and HA patients. The difference in the OSS between the aTSA and PyCHA groups exceeded the minimal clinically important difference of 4.3. There was no difference in revision rates between the groups. CONCLUSIONS: This study represents the largest cohort of patients treated with PyCHA and is the first to compare stemmed PyCHA with HA and aTSA in young patients. In the short term, PyCHA appear to be a promising implant with an excellent implant retention rate. In patients aged <60 years, the revision rate is comparable between PyCHA and aTSA. However, aTSA remains the implant of choice to optimize early postoperative function. Further studies are required to elucidate the long-term outcomes of PyCHA, particularly how they compare with those of HA and aTSA in young patients.

A review of the New Zealand National Joint Registry to compare the outcomes of Coonrad-Morrey and Latitude total elbow arthroplasty.

BACKGROUND: Total elbow arthroplasty has traditionally been used in the treatment of inflammatory arthropathy patients. More and more, however, its use is expanding to include acute trauma and sequelae of trauma. In New Zealand, the most commonly used prosthesis is the Coonrad-Morrey prosthesis, but the Latitude prosthesis has gained in popularity, with a 3-fold increase in implantation over the past 5 years. METHODS: Prospectively collected national joint registry data were used to compare the survival rates of these prostheses. Underlying diagnoses, reasons for revision, and patient-reported outcome measures, as well as patient age and exact implants used, were all recorded. Statistical analysis involved survival analysis using Kaplan-Meier curves and the paired Student t test. RESULTS: Over the 18-year study interval, the Coonrad-Morrey prosthesis has shown consistently lower revision rates than the Latitude prosthesis. This was true for both the linked and unlinked Latitude prostheses and was not affected by radial head replacement or underlying diagnosis. In all cases, the risk of revision for the Coonrad-Morrey prosthesis was reduced by at least 65% compared with the Latitude prosthesis. CONCLUSION: This study using New Zealand Joint Registry data shows a lower failure rate of the Coonrad-Morrey elbow prosthesis compared with the Latitude prosthesis. The hazard ratio for a revision procedure for the Coonrad-Morrey prosthesis compared with the Latitude prosthesis was 0.28 (95% confidence interval, 0.14-0.55). This lower rate was evident irrespective of linkage and radial head replacement. The reason for the lower rate of revision with the Coonrad-Morrey prosthesis is likely multifactorial, but perhaps when used by lower-volume surgeons, the Coonrad-Morrey prosthesis may confer better implant longevity.

Propionibacterium acnes in primary shoulder arthroplasty: rates of colonization, patient risk factors, and efficacy of perioperative prophylaxis.

BACKGROUND: Recent literature has shown that Propionibacterium acnes can be cultured from superficial and deep layers of the shoulder. Our aims were to assess the rate of P. acnes colonization in patients undergoing primary shoulder arthroplasty, to identify patient-related risk factors, and to evaluate the efficacy of our perioperative antisepsis protocol. METHODS: Thirty consecutive patients undergoing primary shoulder arthroplasty were included in our study. Swabs were taken perioperatively (4 superficial and 2 deep wound swabs) and analyzed quantitatively for P. acnes. Cefazolin minimum inhibitory concentration was determined for P. acnes isolates from positive deep cultures. RESULTS: Twenty-two patients (73%) had positive cultures for P. acnes. Male gender (P = .024) and presence of hair (P = .005) had significantly higher rates of P. acnes superficial cultures. Subjects with positive superficial P. acnes cultures (P = .076) and presence of hair with a history of steroid injection (P = .092) were more likely to have deep P. acnes-positive cultures, but this was not statistically significant. Local topical antisepsis measures did not eradicate P. acnes (P = .12). Mean cefazolin minimum inhibitory concentration for P. acnes was 0.32 µg/mL. CONCLUSION: P. acnes is commonly isolated from the skin and deep surgical wounds of patients undergoing primary total shoulder arthroplasty who have not had previous shoulder surgery. Male gender and presence of hair were significant risk factors for P. acnes colonization. Perioperative local topical antisepsis and cefazolin administration were not effective in eliminating P. acnes colonization.

Functional and radiologic outcomes of uncemented reverse shoulder arthroplasty in proximal humeral fractures: cementing the humeral component is not necessary.

BACKGROUND: Our aim was to determine the radiologic and functional outcomes of patients who underwent reverse shoulder arthroplasty (RSA) for proximal humeral fractures and to assess whether the uncemented humeral components put them at risk for early loosening and failure. METHODS: Thirty-three patients were identified in our hospital database (January 2004-December 2012). Twenty patients were assessed using American Shoulder Elbow Surgeons (ASES) score, Constant Shoulder Score (CSS), and the Oxford Shoulder Score (OSS). Up-to-date shoulder radiographs were evaluated for evidence of radiologic loosening. RESULTS: The mean follow-up period was 3.0 years (range, 2.5-7.8 years), and the mean age at the time of surgery was 76.5 years (range, 62-87 years). The mean ASES was 75.9 of 100 (range, 55-98.3), with a mean visual analog scale pain score of 2 of 10. The mean OSS was 42.5 of 48 (range, 35-48), and the mean CSS was 54.1 of 100 (range, 32-72). Upon radiographic assessment of the humeral component, 6 patients (30%) had 3 or more lucent zones, and 12 patients (60%) had a lucent zone measuring more than 2 mm in width; however, only 2 patients (10%) had 3 or more lucent zones measuring 2 mm or more in width and were identified as "at risk of loosening." No patients had tilt or subsidence of the humeral prosthesis. CONCLUSIONS: Our study demonstrated satisfactory functional and radiologic outcomes of patients compared with other studies, suggesting that RSA is a good management option for elderly patients with these fractures. The uncemented nature of the humeral component did not result in early loosening or failure.

Endobutton versus transosseous suture repair of distal biceps rupture using the two-incision technique: a comparison series.

BACKGROUND: The purpose of this study was to report the outcome of a large cohort of patients undergoing distal biceps tendon repair. We compared the endobutton and transosseous suture repair techniques, both performed through a 2-incision approach. METHOD: At an average of 2.1 years after a distal biceps repair, 46 male patients (19 endobutton and 27 transosseous suture) were reviewed. The mean age of our patients was 50 years. RESULTS: Forty-three patients (93%) were satisfied with the results of their distal biceps tendon repair. The average pain score was 1.3 of 10 at a mean 2.1 years after repair. More than 80% of patients had regained their premorbid function in both recreational and occupational activities. The mean Mayo Elbow Performance Score was 93 of 100. Biodex strength testing demonstrated restoration of 92% of low-velocity supination power, 102% of high-velocity supination power, and 104% endurance compared with the contralateral limb. There was no statistically significant difference in postoperative strength between the transosseous suture and endobutton groups. There were 3 complications in this series, 1 case of heterotopic ossification and 2 cases of injury to the lateral cutaneous nerve of the forearm. CONCLUSION: In this large cohort of 2-incision distal biceps repairs, we found a high degree of patient satisfaction and a low complication rate. We did not find any difference in clinical outcome with regard to subjective patient rating, pain, range of motion, or supination strength when comparing the 2-incision endobutton and transosseous suture fixation techniques.

Functional outcome and the structural integrity of arthroscopic Bankart repair: a prospective trial.

BACKGROUND: Recurrent anterior shoulder dislocations are common in young patients with Bankart lesions. Arthroscopic repair is an established treatment; however, recurrent instability occurs in up to 35% of patients. It is unclear whether recurrence is the result of a failure of the surgical repair to heal or a repeat injury. The aim of the present pilot study was to assess radiographic healing of Bankart lesions 6 months post surgical repair and identify any correlations between radiographic findings and subsequent recurrent dislocations. METHODS: Eighteen patients underwent arthroscopic Bankart repair for recurrent instability. Magnetic resonance (MR) arthrograms were obtained both pre-operatively and 6 months postoperatively. Standard T1 and T2 views were obtained along with an abduction and external rotation (ABER) view. Patients were followed for a minimum of 4 years for the risk of recurrence, and functional outcomes were obtained, including the American Shoulder and Elbow Surgeons Subjective Shoulder Scale, Ontario Shoulder Instability Index, Oxford Shoulder Instability Score and 12-Item Short Form Health Survey. Scores were correlated with pre-operative and postoperative MR findings. RESULTS: Six of 18 patients developed recurrent instability. We could not identify correlations between reconstructed labrum (labral bumper) position, failure at suture sites and ABER findings with recurrent instability or functional outcome. Paradoxically, there was a nonstatistically significant trend for patients with no clefts between the labrum and the glenoid at any points along the repair to have worse outcomes than patients with partial or complete clefts. CONCLUSIONS: In our pilot study, MR arthrogram was used to evaluate the labrum in detail 6 months postoperatively. Despite its proven ability to detect labral lesions, we were unable to demonstrate any features on postoperative MR arthrogram that predicted either functional outcome or recurrent instability. At 6 months post operation, functional recovery and the risk of recurrence may not depend on the anatomical appearance of the labrum alone.

A comparison of concentric and eccentric glenospheres in reverse shoulder arthroplasty: a randomized controlled trial.

BACKGROUND: Inferior scapular notching following reverse shoulder arthroplasty is due to mechanical impingement and, in some studies, has been associated with poorer functional scores, lower patient satisfaction, and more limited shoulder motion. We aimed to test the hypothesis that inferior positioning of the center of rotation with eccentric glenosphere designs decreases the adduction deficit before impingement occurs and improves clinical outcome. METHODS: A randomized, controlled, double-blinded trial was performed. According to the results of a power analysis, fifty patients undergoing reverse shoulder arthroplasty for the diagnosis of cuff tear arthropathy were randomized intraoperatively to receive either a concentric or eccentric glenosphere. The glenoid baseplate was positioned flush to the inferior border of the glenoid before the glenosphere was then attached. Notching was assessed using an anteroposterior radiograph, and clinical outcome was assessed using the visual analog pain scale score, shoulder function rating, American Shoulder and Elbow Surgeons score, and Oxford shoulder score. Active forward elevation and external rotation were assessed. The outcome assessor was blinded to the treatment group. The mean follow-up period for the groups was forty-three and forty-seven months. RESULTS: Patient demographics and preoperative scores were similar between the groups. At the time of the final follow-up, four patients (14.8%) in the concentric group had developed inferior scapular notching (two with Nerot grade I and two with Nerot grade II), ranging in size from 1.1 to 7.4 mm, compared with one patient (4.3%; Nerot grade I) in the eccentric group (p = 0.36). No notching occurred in any patient with glenoid overhang of >3.5 mm. No significant difference between the groups was seen with respect to functional outcome scores, patient satisfaction, or shoulder motion. CONCLUSIONS: There were no differences in notching rates or clinical outcomes between concentric and eccentric glenospheres following reverse shoulder arthroplasty. Inferior glenosphere overhang of >3.5 mm, however, prevented notching. This may be achieved with a modified surgical technique, but eccentric glenospheres provide an additional option. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

A correlation study of the American Shoulder and Elbow Society Score and the Oxford Shoulder Score with the use of regression analysis to predict one score from the other in patients undergoing reverse shoulder joint arthroplasty for cuff tear arthropathy.

BACKGROUND: More than 30 different scoring systems are available for evaluating outcomes of shoulder surgery. Unfortunately, given the multitude of scoring systems, there is no objective method to compare results between studies when different scoring systems are utilized. METHODS: We compared the American Shoulder and Elbow Society score (ASES) and the Oxford Shoulder Score (OSS) in patients undergoing reverse shoulder arthroplasty for cuff tear arthropathy. Twenty-nine patients had the ASES and OSS recorded pre-operatively, and at 6 and 12 months follow-up. The paired scores were assessed for their degree of correlation and sensitivity to change over time. Linear regression analysis was used to formulate a regression equation to predict one score from the other. RESULTS: The ASES and OSS correlated well with a Pearson's correlation coefficient of 0.91 (p < 0.0001, n = 87). Both scores were sensitive to change. Regression analysis yielded a formula to predict the ASES from the OSS and vice versa with good accuracy (r (2 )= 0.83, F 1,85 = 422.6, p < 0.0001). CONCLUSIONS: Where good correlation exists, regression formulae can be used to accurately predict one score from the other in a specific population that it has been validated for. This can be of benefit when objectively comparing outcomes between studies using these two scoring systems.

Comparison of functional outcomes of reverse shoulder arthroplasty with those of hemiarthroplasty in the treatment of cuff-tear arthropathy: a matched-pair analysis.

BACKGROUND: Rotator cuff-tear arthropathy has traditionally represented a challenge to the shoulder arthroplasty surgeon. The poor results of conventional total shoulder arthroplasty in rotator-cuff-deficient shoulders due to glenoid component loosening have led to hemiarthroplasty being the traditional preferred surgical option. Recently, reverse total shoulder arthroplasty has gained increasing popularity because of a clinical perception of an improved functional outcome, despite the lack of comparative data. The aim of this study was to compare the early functional results of hemiarthroplasty with those of reverse shoulder arthroplasty in the management of cuff-tear arthropathy. METHODS: The results of 102 primary hemiarthroplasties for rotator cuff-tear arthropathy were compared with those of 102 reverse shoulder arthroplasties performed for the same diagnosis. Patients were identified from the New Zealand Joint Registry and matched for age, sex, and American Society of Anesthesiologists (ASA) scores. Oxford Shoulder Scores (OSS) collected at six months postoperatively as well as mortality and revision rates were compared between the two groups. RESULTS: There were fifty-one men and fifty-one women in each group, with a mean age of 71.6 years in the hemiarthroplasty group and 72.6 years in the reverse shoulder arthroplasty group. The mean OSS at six months was 31.1 in the hemiarthroplasty group and 37.5 in the reverse shoulder arthroplasty group. At the time of follow-up, there were nine revisions in the hemiarthroplasty group and five in the reverse shoulder arthroplasty group. No difference in mortality rate was seen between the two groups. CONCLUSIONS: In this unselected population with rotator cuff-tear arthropathy, controlled for age, sex, and ASA score, reverse shoulder arthroplasty resulted in a functional outcome that was superior to that of hemiarthroplasty. Longer-term follow-up is needed to confirm these findings.

Triceps Split and Snip approach to the elbow: surgical technique and biomechanical evaluation.

BACKGROUND: A number of posterior approaches to the elbow have been described, which vary in the quality of the exposure and morbidity to the triceps mechanism. We describe an adapted technique, the Triceps Split and Snip, which may offer improved surgical exposure during posterior approach to the elbow. We aimed to compare the strength of the triceps repair in this approach to a more traditional approach described by Bryan and Morrey. METHODS: Sixteen pairs of cadaveric elbows were randomized by surgical group and operative side. The Triceps Split and Snip and Bryan-Morrey approaches were each performed on eight specimens, followed by repair of the triceps; the contralateral elbow served as the control. The specimens were then mounted on a material testing system and a constant velocity elongation was applied. RESULTS: The mean load to failure for the Bryan-Morrey group was 421N (range 349-536N). While the Triceps Split and Snip group was 388N (range 267-550N). The percentage ultimate strength loss was 40% for both groups. No significant difference was found in comparing the mean load to failure between the Triceps Split and Snip approach and the Bryan-Morrey approach. CONCLUSIONS: The Triceps Split and Snip approach is a technically simple approach to perform and repair, and provides excellent exposure of the elbow and distal humerus. The tensile strength of the triceps repair following this approach is equivalent to that of the Bryan-Morrey approach.

Blood vessel hyperpermeability and pathophysiology in human tumour xenograft models of breast cancer: a comparison of ectopic and orthotopic tumours.

BACKGROUND: Human tumour xenografts in immune compromised mice are widely used as cancer models because they are easy to reproduce and simple to use in a variety of pre-clinical assessments. Developments in nanomedicine have led to the use of tumour xenografts in testing nanoscale delivery devices, such as nanoparticles and polymer-drug conjugates, for targeting and efficacy via the enhanced permeability and retention (EPR) effect. For these results to be meaningful, the hyperpermeable vasculature and reduced lymphatic drainage associated with tumour pathophysiology must be replicated in the model. In pre-clinical breast cancer xenograft models, cells are commonly introduced via injection either orthotopically (mammary fat pad, MFP) or ectopically (subcutaneous, SC), and the organ environment experienced by the tumour cells has been shown to influence their behaviour. METHODS: To evaluate xenograft models of breast cancer in the context of EPR, both orthotopic MFP and ectopic SC injections of MDA-MB-231-H2N cells were given to NOD scid gamma (NSG) mice. Animals with matched tumours in two size categories were tested by injection of a high molecular weight dextran as a model nanocarrier. Tumours were collected and sectioned to assess dextran accumulation compared to liver tissue as a positive control. To understand the cellular basis of these observations, tumour sections were also immunostained for endothelial cells, basement membranes, pericytes, and lymphatic vessels. RESULTS: SC tumours required longer development times to become size matched to MFP tumours, and also presented wide size variability and ulcerated skin lesions 6 weeks after cell injection. The 3 week MFP tumour model demonstrated greater dextran accumulation than the size matched 5 week SC tumour model (for P < 0.10). Immunostaining revealed greater vascular density and thinner basement membranes in the MFP tumour model 3 weeks after cell injection. Both the MFP and SC tumours showed evidence of insufficient lymphatic drainage, as many fluid-filled and collagen IV-lined spaces were observed, which likely contain excess interstitial fluid. CONCLUSIONS: Dextran accumulation and immunostaining results suggest that small MFP tumours best replicate the vascular permeability required to observe the EPR effect in vivo. A more predictable growth profile and the absence of ulcerated skin lesions further point to the MFP model as a strong choice for long term treatment studies that initiate after a target tumour size has been reached.

Radius morphology and its effects on rotation with contoured and noncontoured plating of the proximal radius.

BACKGROUND: The radius has a sagittal bow and a coronal bow. Fractures are often treated with volar anterior plating. However, the sagittal bow is often overlooked when plating. This study looks at radial morphology and the effect of plating the proximal radius with straight plates and then contoured plates bowed in the sagittal plane. We report our findings and their effect on forearm rotation. MATERIALS AND METHODS: Morphology was investigated in 14 radii. Attention was paid to the proximal shaft of the radius and its sagittal bow; from this, 6-, 7-, and 8-hole plates were contoured to fit this bow. A simple transverse fracture was then made at the apex of this bow in 23 cadaver arms. Supination and pronation were compared when plating with a straight plate and a contoured plate. Ten cadavers underwent ulna plating at the same level. The effect on rotation of fractures plated in the distal-third shaft was also measured. RESULTS: A significant reduction in rotation was found when a proximal radius fracture was plated with a straight plate compared with a contoured plate: 10.8°, 12.8°, and 21.7° for 6-, 7-, and 8-hole plates, respectively (P < .05). Forearm rotation was decreased further when a longer plate was used. Ulna or distal shaft plating did not reduce rotation. CONCLUSION: This study has shown a significant sagittal bow of the proximal shaft of the radius. Plating this with contoured plates in the sagittal plane improves rotation when compared with straight plates. Additional ulna plating is not a source of reduced forearm rotation.

An in vivo kinematic study of the reverse shoulder joint replacement.

As of now few studies have investigated the kinematics of the reverse shoulder arthroplasty (RSA) in patients and none on how this may be affected by glenosphere shape or size. There have been a few biomechanical studies evaluating the RSA. These studies have modelled and estimated that a large amount of movement is available at the glenohumeral articulation, when using a standard glenosphere, with even more movement using an eccentric or large glenosphere. However, the in vivo kinematics of the RSA has not been determined. Therefore, we conducted a study to assess the in vivo kinematics of the RSA and to observe what affect the glenosphere type would have. Areas of specific interest were the maximal abduction, the ratio of glenohumeral to scapulothoracic motion, and an observation of what occurs during notching. We obtained 18 patients who had high functioning reverse shoulder replacements, with surgery greater than a year ago. We assessed the kinematics, first with fluoroscopy, where we obtained 5 images at various levels of abduction. Then, at the same sitting, electromagnetic sensors were placed on the lateral epicondyle, acromion and base of the scapular spine. These sensors were attached to the Polhemus 3space tracking system that allowed us to measure the movement of the humerus and the movement of scapula during cycles of abduction. Our results demonstrated that the RSA is able to reproduce kinematics similar to the quoted physiological kinematics. Eccentric glenospheres had higher abduction and are less likely to experience superior impingement of the humerus on the under surface of the acromion or develop the more severe stages of notching. The range of movement in our study was highest in the 36-mm eccentric glenospheres and lowest in the 44-mm concentric glenospheres. Notching, although not associated with a poor outcome score or a lower range of movement was more prevalent in patients whose first phase of movement, consisted mainly of scapulothoracic motion.

Comparison of functional outcomes of reverse shoulder arthroplasty versus hemiarthroplasty in the primary treatment of acute proximal humerus fracture.

BACKGROUND: Treatment of complex proximal humeral fractures remains controversial. In cases where adequate open reduction and internal fixation cannot be achieved, hemiarthroplasty has been the traditional treatment; however, clinical results have been mixed. Reverse shoulder arthroplasty (RSA) has been suggested as an alternative, and this study aimed to compare the functional results of RSA versus hemiarthroplasty in patients with acute proximal humeral fracture. METHODS: Ten patients with acute proximal humerus fractures unsuitable for internal fixation (mean age 77) who underwent RSA for acute proximal humerus fracture unsuitable for internal fixation against the outcomes of 10 patients (mean age 75) who had previously undergone hemiarthroplasty for the same indication. Functional scores and radiographic outcomes were assessed at 22-44 months follow up. RESULTS: At follow up the mean American Shoulder and Elbow Scorev score was 65 (range 40-88) in the RSA group and 67 (26-100) in the hemiarthroplasty group. Mean Oxford Shoulder scores were 29 (15-56) and 22 (12-34), respectively. Mean forward elevation was 115 degrees (range 45-140 degrees) and active external rotation was 49 degrees (5-105 degrees) in the RSA group, versus 108 degrees (50-180 degrees) and 48 degrees (10-90 degrees) in the hemiarthroplasty group. No statistically significant differences in outcome scores or range of motion were seen. CONCLUSION: In these early results, the anticipated functional gains of RSA over hemiarthroplasty were not realized, suggesting the use of RSA for treatment of proximal humeral fractures should remain guarded. Larger prospective trials are necessary to identify the optimal management of patients in this situation.

Carbon dioxide sensing modulates lifespan and physiology in Drosophila.

For nearly all life forms, perceptual systems provide access to a host of environmental cues, including the availability of food and mates as well as the presence of disease and predators. Presumably, individuals use this information to assess the current and future states of the environment and to enact appropriate developmental, behavioral, and regulatory decisions. Recent work using the nematode worm, Caenorhabditis elegans, and the fruit fly, Drosophila melanogaster, has established that aging is subject to modulation through neurosensory systems and that this regulation is evolutionarily conserved. To date, sensory manipulations shown to impact Drosophila aging have involved general loss of function or manipulation of complex stimuli. We therefore know little about the specific inputs, sensors, or associated neural circuits that affect these life and death decisions. We find that a specialized population of olfactory neurons that express receptor Gr63a (a component of the olfactory receptor for gaseous phase CO(2)) affects fly lifespan and physiology. Gr63a loss of function leads to extended lifespan, increased fat deposition, and enhanced resistance to some (but not all) environmental stresses. Furthermore, we find that the reduced lifespan that accompanies exposure to odors from live yeast is dependent on Gr63a. Together these data implicate a specific sensory cue (CO(2)) and its associated receptor as having the ability to modulate fly lifespan and alter organism stress response and physiology. Because Gr63a is expressed in a well-defined population of neurons, future work may now be directed at dissecting more complex neurosensory and neuroendocrine circuits that modulate aging in Drosophila.

The SMR reverse shoulder prosthesis in the treatment of cuff-deficient shoulder conditions.

BACKGROUND: Reverse total shoulder arthroplasty (RSA) is a relatively recent concept that provides further options in the management of cuff-deficient shoulder disorders. While early results utilizing the Delta III prosthesis (DePuy, Warsaw, IN) have been promising, there is limited data in the literature on outcomes utilizing differing prosthetic designs. We report on the outcomes of Reverse total shoulder arthroplasty (RSA) utilizing a previously unreported prosthesis, the SMR Modular Shoulder System (Systema Multiplana Randelli, Lima-LTO, Italy). MATERIAL AND METHODS: 49 arthroplasties in 48 patients who underwent Reverse Shoulder Arthroplasty with the SMR prosthesis were available for follow up. There were 10 males and 38 females with a mean age of 78.9 years (55-94) at time of operation. The most common indications were cuff tear arthropathy and osteoarthritis with cuff deficiency (66%), followed by fracture and fracture sequelae (16%). RESULTS: At a mean 38 months follow up, 89% of patients rated their outcome as good or excellent. The mean American Shoulder and Elbow Surgeon Score was 70.1 (range 3-100), and the mean Oxford Shoulder Score 22.0 (12-47). The mean active anterior elevation was 122 degrees (range 45-180) and the mean external rotation 14.7 degrees (25-75). Inferior glenoid notching was seen in 24% of patients. There was no radiological evidence of component loosening and no reoperations. CONCLUSION: Modern RSA designs give encouraging results in the treatment of cuff deficient shoulder conditions. Our early experience with the SMR RSA shows favourable outcomes and a low rate of complications. LEVEL OF EVIDENCE: Level 4 Retrospective case series, no control group.

Biomechanical evaluation of different designs of glenospheres in the SMR reverse total shoulder prosthesis: range of motion and risk of scapular notching.

BACKGROUND: Reverse total shoulder arthroplasty is a treatment option for cuff tear arthropathy. Scapular notching remains a concern. This biomechanical study compared the range-of-motion in different designs of glenospheres and hence the relative risk of scapular notching. METHOD: A precision coordinate device was used to investigate four different designs of glenospheres (SMR prosthesis); 36 mm concentric (Standard), 36 mm eccentric, 44 mm concentric, and 44 mm eccentric glenospheres. The centre of rotation in each design was first established. The position of the humeral prosthesis was recorded in the plane of the scapula to compare the degree of adduction and the total range-of-motion. RESULTS: Eccentric glenospheres were found to improve range-of-motion by allowing a higher degree of adduction. Larger diameter glenospheres were found to improve range-of-motion by increasing adduction and abduction. Compared to the 36 mm concentric (standard) glenosphere, the 36 mm eccentric glenosphere improved adduction by 14.5 degrees, the 44 mm concentric glenosphere improved adduction by 11.6 degrees, the 44 mm eccentric glenosphere improved adduction by 17.7 degrees. CONCLUSION: Eccentric glenospheres with a center-of-rotation placed more inferiorly were shown to improve adduction. This design may reduce the clinical incidence of scapular notching.