Total elbow arthroplasty (TEA) has been shown to be a treatment option for elderly patients with complex distal humeral fractures and osteoporotic bone. The published results have often included rheumatoid patients who traditionally would be expected to do well from elbow arthroplasty. Only short-term results have been published using this technique in non-rheumatoid patients.

The current study contains the largest number and longest follow-up of non-rheumatoid patients whose fractures have been treated with a non-custom TEA. In total there were 26 patients, mean age 72 years, 22 female and 4 male, 25% dominant arm. The mean follow-up was of 5 years. There was 1 case of loosening, 1 radial nerve palsy and 2 cases of heterotrophic ossification. At final review the mean range of flexion/extension was 97.5 degrees and the mean range of pronation/supination was 151.75 degrees. The mean Mayo Elbow Performance score was 92.

We would suggest that TEA provides a very satisfactory outcome in elderly patients with complex distal humeral fractures, the benefit of which can be observed at a mean of 5 years.

Background. The quest for the perfectly designed elbow prosthesis continues as instability and loosening remain the foremost reasons for the failure of total elbow replacement (TER). The Discovery® Elbow System (Biomet, UK) (Figure 1), which has been used in UK since 2003, is one of the latest generations of linked prosthesis. This system was designed to decrease polyethylene-bushing wear, improve anatomic stem design, restore elbow joint biomechanics, and produce a hinge that could be easily revised. This report describes the short term outcome of TER using the Discovery® Elbow System. Patients and Methods. A total of 60 TERs including 48 primary and 12 revisions were performed between 2003 and 2008. Patients included 21 males (37%) and 36 females (63%) with a mean age of 63 years. The indications for primary TER were advanced rheumatoid arthritis (n=19), osteoarthritis (n=16), post traumatic osteoarthritis (n=9), acute fractures (n=3), and haemophilic arthropathy (n=1). The outcome was assessed using pain score, Liverpool Elbow Score (LES), and range of movement during a mean follow-up of 26 months. Associated complications were documented. Radiological assessment included evaluation for loosening, instability and periprosthetic fractures. Results. The mean LES was significantly (p<0.001) improved from 3.8 (±1) pre-operatively to 6.9 (±2) at the final follow- up. Significant improvements were noted in elbow flexion from 100° (±22) to 120° (±15), supination from 41° (±28) to 65° (±20) and pronation from 52° (±22) to 72° (±18). There was no significant change in elbow extension. Mean improvement in flexion-extension and pronation-supination arc was 22° and 44°, respectively. 46 cases (77%) were completely pain-free at the final follow-up. The main complications included deep infection (4 cases – treated with staged revision TER), postoperative ulnar neuropathy (3 cases–treated with decompression), intra-operative fractures of medial condyle (3 cases – treated non-operatively with brace), and elbow haemarthrosis (1 case). Discussion. TER with Discovery® Elbow System resulted in either no pain or mild pain in 87% of cases. Patients undergoing Acclaim, Souter-Strathclyde, GSB III, and Coonrad-Morrey TER have been reported to have no/mild pain in 64%, 67%, 50–92% and 60–100% of cases, respectively. A 22° improvement in flexion-extension arc is comparable to that of Acclaim (23°), Souter-Strathclyde (15°), GSB III (19–33°), and Coonrad-Morrey (17–26°) TER. An improvement of 44° in pronation-supination arc in our series is also comparable to that of 31–67° reported for GSB III and higher than the Coonrad-Morrey prosthesis (21–28°). In terms of complications, an infection rate of 6.7% is consistent with those reported for GSB III TER (7–11%) and Coonrad-Morrey (6–8%). The incidence of persistent ulnar neuropathy was lower compared to GSB III TER (11–14%), Coonrad-Morrey (12–26%), and Acclaim (8%). While the survival of Discovery TER was 93%, the survival of GSB III (5–6 years) and Coonrad-Morrey (5 years) has been reported as 71–85% and 72–90%. The results indicate that Discovery® Elbow System is an effective device for total elbow arthroplasty in terms of functional improvement, pain relief and range of motion at short-term follow-up

Implant designs for hip and knee arthroplasty have undergone a continual improvement process, but development of implants for total elbow arthroplasty (TEA) have lagged behind despite the marked mechanical burden placed on these implants. TEA is not as durable with failure rates approaching thirty percent at five years. The Coonrad-Morrey (Zimmer, Warsaw, IN), a linked design, remains the standard-bearer, employing polyethylene bushings through which a metal axle passes. A common failure mode is bushing wear and deformation, causing decreased joint function as the bushing-axle constraint decreases and osteolysis secondary to release of large volumes of wear debris. Improving upon this poor performance requires determining which factors most influence failure, so that failure can be avoided through design improvements. The approach integrates clinical observations of failed TEAs with implant retrieval analysis, followed by measurements of loads across the elbow for use in stress analyses to assess the performance of previous designs, and, finally, new design approaches to improve performance. Examination of the clinical failures of more than seventy Coonrad-Morrey TEAs revealed patterns of decreased constraint and stem loosening. Implant retrieval analysis from more than thirty of these cases showed excessive bushing deformation and wear and burnishing of the fixation stems consistent with varus moments across the joint. To determine loads across the elbow, motion analysis data were collected from eight TEA patients performing various activities of daily living. The kinematic data were input into a computational model to calculate contact forces on the total elbow replacement. The motion that produced the maximum contact force was a feeding motion with the humerus in 90° of abduction. For this motion, the joint reaction forces and moments at the point of maximum contact were determined from a computational model. We applied these loads to numerical models of the articulating bushings and axle of the Coonrad-Morrey to examine polyethylene strains as measures of damage and wear. Strain patterns in response to the large varus moment applied to the elbow during feeding activities showed extensive plastic deformation in the locations at which deformation and wear damage were observed in our retrieved implants (Fig. 1). Finally, we examined a new semi-constrained design concept intended to meet two goals: transfer contact loads away from the center of the joint, thus allowing contact to provide a larger internal moment to resist the large external varus moment; and reduce polyethylene strains by utilizing curved contacting surfaces on both the axle and the bushings (Fig. 2). After a sensitivity analysis to determine optimal dimensional choices (e.g., bushing and axle radii), we compared the resulting polyethylene strains between the Coonrad-Morrey and new design at locations that experienced the largest strains (Fig. 3). Substantial decreases were achieved, suggesting far less deformation and wear, which should relate to marked improvements in performance. Currently, we are incorporating this new design concept, along with alterations in stem design achieved from examination of load transfer at the fixation interfaces based on the same loading conditions, to achieve an implant system intended to improve the performance of TEA

Background. Previously, the Coonrad-Morrey elbow system has typically been performed using linked-type total elbow arthroplasty (TEA) implants. However, this implant have been reported to be associated with some problems, such as wearing down, loosening, the complexity of the necessary surgical techniques and inappropriate implant size for Asian people. The Discovery elbow system (Biomet Inc., Warsaw, US) has recently been developed and it has many advantages when compared to Coonrad-Morrey implant, but the treatment outcome for this system is unclear in patients with rheumatoid arthritis (RA). Objectives. The aim of this study was to clarify the outcome of TEA using the Discovery elbow system. Methods. Eleven RA patients (13 elbows) who underwent TEA using the Discovery elbow system were investigated in this study. Two patients (3 elbows) were males, and 9 patients (10 elbows) were females. Ten were right elbows, and 3 were left elbows. Two elbows has Larsen grade “disease, 7 had grade” disease and 4 elbows underwent revision surgery. The surgical approach used for all cases was Campbell's posterior approach. The Discovery elbow system was installed using cemented fixation. Two weeks after the operation, ROM exercise was started. The elbow ROM, Mayo elbow performance score (MEPS), and any complications observed at baseline, 6 months and 24 months after surgery were assessed. Results. The preoperative elbow ROM (mean±SD) was −33.4±4.4° in extension, 133.5±3.4° in flexion, 48.5±8.4° pronation and 67.7±5.7° in supination. The postoperative elbow ROM (mean±SD) was −18.5±6.2° in extension, 112.7±6.1° in flexion, 70.0±3.4° in pronation and 73.7±1.6° in supination. As a result, a significant improvement was observed in extension, flexion and pronation. The MEPS improved significantly at 6 months and 24 months after surgery. In addition, no implant loosening was found or revision surgery was required at 24 months after surgery. Conclusions. In this study, the elbow function was observed to significantly improve by TEA using the Discovery elbow system based on the short-time outcome. However, further study is still needed to clarify the long-term outcome of this implant in RA patients

Purpose. Clinical outocome of revision total elbow arthroplasty(TEA) in rheumatoid arthritis(RA) patients were evaluated. Methods. Clinical outocome of revision TEA that underwent between 2005 and 2013 were evaluated. Causes of revision, implanted revised prosthesis, a clinical score (the Japanese Orthopaedic Association (JOA) elbow assessment score), the arc of motion and complications were investigated. Totally, 6 patients underwent revision TEA. The patients were females with a mean age of 60.4 years (range, 32 to 72). Results. Seventy-two primary TEAs were done in corresponding period. Six out of 72 (8.3%) TEAs were revised. Causes of revision were loosening, instability (dislocation) and breakage of a component in 3, 2 and 1 cases, respectively. A mean duration from initial TEA to revision surgery was 10.3 years (range, 1 to 13). Semi-constrained arthroplasties (5 Coonrad-Morrey, 1 Discovery) were used for revision surgery. A mean JOA elbow assessment score improved from 59 to 81 point at the time of follow up. The mean ROM, flexion was improved 125 degrees, to 131 degrees. Extension, supination and pronation was not changed. A fracture at the time of implant withdrawal occurred as an intraoperative complication. The fractures were recovered by wiring with autologous bone graft from the ilium and a good bone union was achieved in 2 out of 3 cases. However, a re-revision surgery with plate was required in the remaining case. Conclusions. Revision TEA provided a satisfactory functional outcome. An intraoperative fracture was a critical complication in this procedure

Background. Total elbow arthroplasty (TEA) has become an established procedure in the treatment of patients with rheumatoid arthritis (RA). However, there is little information on whether limited extension of the elbow affects clinical outcome scores after TEA and what causes the limited extension. Methods. We retrospectively analyzed fifty-four cases of primary TEA in patients with RA. There were seven men and thirty-nine women with a mean age of 63.6 years (range, thirty to eighty years). Thirty-seven of Coonrad-Morrey and seventeen of Discovery prostheses were used. The mean length of follow-up was 7.1 ± 4.0 years (range 2.0–14.6 years). Mayo Elbow Performing Score (MEPS) and radiological measurements were recorded. Anteroposterior and lateral radiographs were assessed before and after the operation and at the latest follow-up. Widening of the joint space was calculated by subtracting the length measured on the postoperative radiograph from that on the preoperative radiograph. Results. MEPS was significantly improved after surgery (51.2 to 91.1), especially in the domains of pain (18.6 to 43.1), stability (5.9 to 10) and daily function (10.7 to 21.0). Range of motion was significantly improved, in flexion (111.3° to 140.6°), pronation (62.1° to 72.3°), and supination (60.2° to 72.3°), but not in extension (30.0° to 28.8°). Simple and multivariate analyses showed that longer disease duration (p = 0.004), higher Larsen grade (p = 0.013), worse pronation/supination arc (p = 0.004) and worse postoperative extension (p = 0.033), but not postoperative flexion (p = 0.532), were significantly correlated with lower MEPS daily function. Conversely, simple and multivariate analyses showed that worse postoperative extension was correlated with lower MEPS daily function (p = 0.005) and worse preoperative extension (p < 0.001). Radiological analyses showed that, in the limited extension group (≧40°), the degree of extension was correlated with radiological widening of the joint. Conclusions. In linked TEA, perioperative widening of the elbow joint caused limited extension and worse daily function in patients with RA

As a treatment for end-stage elbow joint arthritis, total elbow replacement (TER) results in joint motions similar to the intact joint; however, bearing wear, excessive deformations and/or early fracture may necessitate early revision of failed implant components. Compared to hips, knees and shoulders, very little research has been focused on the evaluation of the outcomes of TER, possible failure mechanisms and the development of optimal designs. The current study aims to develop computational models of TER implants in order to analyze implant behaviour; considering contact stresses, plastic deformations and damage progression. A geometrical model of a TER assembly was developed based on measurements from a Coonrad-Morrey TER implant (Zimmer, Inc., Warsaw, IN). Ultra high molecular weight polyethylene (UHMWPE) nonlinear elasto-plastic material properties were assigned to the humeral and ulnar bushings. A frictional penalty contact formulation with a coefficient of friction of 0.04 was defined between all of the surfaces of the model to take into account every possible interaction between different implant components in vivo. The loading scenario applied to the model includes a flexion-extension motion, a joint force reaction with variable magnitude and direction and a time varying varus-valgus (VV) moment with a maximum magnitude of 13 N.m, simulating a chair-rise scenario as an extreme loading condition. An explicit dynamic finite element solver was used (ABAQUS Explicit, Dassault Systèmes, Vélizy-Villacoublay, France), due to improved capabilities when performing large deformation analyses. Model results were compared directly with corresponding experimental data. Experimental wear tests were performed on the abovementioned implants using a VIVO (AMTI, Watertown, MA) six degree-of-freedom (6-DOF) joint motion simulator apparatus. The worn TER bushings were scanned after the test using micro computed tomography (µCT) imaging techniques, and reconstructed as 3D models. Comparisons were made based on the sites of damage and deformed geometries between the numerical results and experimental test data. In addition to that, parametric geometrical models were developed using worn geometry of the retrievals in order to account for primary wear and deformations while simulating long-term contact stress and secondary damage progression on the bushings (Fig. 1). Contact pressure distributions on the humeral and ulnar bushings correlate with the sites of damage as represented by the µCT data and gross observation of clinical retrievals. Furthermore, deformation patterns and kinematics of the components are in good agreement with the experimental results (Fig.2). Excessive plastic deformations are evident in both the numerical and the experimental results close to the regions with high contact pressures. Simulating parametric initially-worn geometries results in the formation of secondary damage zones, as well as redistribution of contact stresses and contact locations (Fig. 3). The results demonstrate UHMWPE bushing damage due to different loading protocols. Numerical results demonstrate strong agreement with experimental data based on the location of deformation and creep on bushings and exhibit promising capabilities for predicting the damage and failure mechanisms of TER implants. For figures/tables, please contact authors directly.

Introduction. The aim of this study is to analyse the effect of the degree of coverage of the Total Elbow implant with cement and the significance of cementation index as a predictor of failure. Material/methods. Fifty elbows in forty seven patients who had undergone the Coonrad-Morrey TER were included in the study. The post-operative radiographs were evaluated for the cementation index. Failures and revisions were documented. Statistical analysis was done to evaluate the cementation index as a predictor of failure. Results. The mean period of follow up was 4.67 ± 2.85 years. The mean cementation index of the humerus (CIH) was 1.22 ± 0.28 (range 0.7 to 2.1). The mean cementation index of the ulna (CIU) was 1.10 ± 0.18 (range 0.77 to 1.72). The Kolmogorov-Smirnov test, used to test the type of distribution, showed that both the indices had a normal distribution (p > 0.05). Both the humeral and ulnar cementation indices were not found to be statistically significant predictors of failure (p > 0.05). Conclusions. The cementation index is an objective method of assessment of the coverage of the implant with cement. In the present series, the cementation index of the humerus varied from 0.7 to 2.1 and that of the ulna varied from 0.77 to 1.72 but both were not found to be statistically significant. A larger study with adequate follow-up should be done to establish the minimum cement mantle that can be considered adequate for the long term survivorship of the prosthesis