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Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_8 | Pages 2 - 2
1 Aug 2020
Matache B King GJ Watts AC Robinson P Mandaleson A
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Total elbow arthroplasty (TEA) usage is increasing owing to expanded surgical indications, better implant designs, and improved long-term survival. Correct humeral implant positioning has been shown to diminish stem loading in vitro, and radiographic loosening in in the long-term. Replication of the native elbow centre of rotation is thought to restore normal muscle moment arms and has been suggested to improve elbow strength and function. While much of the focus has been on humeral component positioning, little is known about the effect of positioning of the ulnar stem on post-operative range of motion and clinical outcomes. The purpose of this study is to determine the effect of the sagittal alignment and positioning of the humeral and ulnar components on the functional outcomes after TEA. Between 2003 and 2016, 173 semi-constrained TEAs (Wright-Tornier Latitude/Latitude EV, Memphis, TN, USA) were performed at our institution, and our preliminary analysis includes 46 elbows in 41 patients (39 female, 7 male). Patients were excluded if they had severe elbow deformity precluding reliable measurement, experienced a major complication related to an ipsilateral upper limb procedure, or underwent revision TEA. For each elbow, saggital alignment was compared pre- and post-operatively. A best fit circle of the trochlea and capitellum was drawn, with its centre representing the rotation axis. Ninety degree tangent lines from the intramedullary axes of the ulna and humerus, and from the olecranon tip to the centre of rotation were drawn and measured relative to the rotation axis, representing the ulna posterior offset, humerus offset, and ulna proximal offset, respectively. In addition, we measured the ulna stem angle (angle subtended by the implant and the intramedullary axis of the ulna), as well as radial neck offset (the length of a 90o tangent line from the intramedullary axis of the radial neck and the centre of rotation) in patients with retained or replaced radial heads. Our primary outcome measure was the quickDASH score recorded at the latest follow-up for each patient. Our secondary outcome measures were postoperative flexion, extension, pronation and supination measured at the same timepoints. Each variable was tested for linear correlation with the primary and secondary outcome measures using the Pearson two-tailed test. At an average follow-up of 6.8 years (range 2–14 years), there was a strong positive correlation between anterior radial neck offset and the quickDASH (r=0.60, p=0.001). There was also a weak negative correlation between the posterior offset of the ulnar component and the qDASH (r=0.39, p=0.031), and a moderate positive correlation between the change in humeral offset and elbow supination (r=0.41, p=0.044). The ulna proximal offset and ulna stem angle were not correlated with either the primary, or secondary outcome measures. When performing primary TEA with radial head retention, or replacement, care should be taken to ensure that the ulnar component is correctly positioned such that intramedullary axis of the radial neck lines up with the centre of elbow rotation, as this strongly correlates with better function and less pain after surgery


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_9 | Pages 55 - 55
1 May 2016
Mori T Kudo H Iwasawa M
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The aim of this study was to assess the long-term results of the Kudo type-5 total elbow prosthesis and compare the results of two types of cemented ulnar components. The Kudo type-5 unlinked total elbow prosthesis (Biomet UK Ltd, Bridgend Wales) was developed in 1993. The stem of humeral component is porous-coated with a plasma spray of titanium alloy for cementless use. The ulnar component may be metal-backed with a porous-coated stem or polyethylene alone; the latter designed mainly for cement use. A metal-backed type without a porous-coated stem designed for cement use also came into being after 2003. Between 1993 and 2010, the Kudo type-5 total elbow arthroplasty was performed on 364 elbows in 274 consecutive patients with rheumatoid arthritis. The mean age of the patients at the time of the operation was 60.7 (27–86) years. Twenty elbows had Larsen grade III, 224 had grade IV, and 120 had grade V changes pre-operatively. Before the operation, 346 elbows had severe or moderate pain, 95 had gross valgus-varus instability. Clinical symptoms and revision rates were assessed 4 to 20 years (mean, 9 years) postoperatively. The mean Mayo elbow performance scores were all poor except for three initially (mean overall score, 39.5 points). The overall score had improved substantially both at the early follow-up (1 to 3 years after the operation) and the latest follow-up (4 to 20 years after the operation), with 89.5 and 84.7 points, respectively. At the latest follow-up the overall result was excellent for 185 elbows, good for 103, fair for 11 and poor for 30, with almost complete relief from pain for 298. The arc of movement had increased from a mean of 85.7 °pre-operatively to 95.1 ° post-operatively, and to 98.1 °at the latest follow-up. Spot welds around the humeral stem suggesting solid osseous integration were often seen in the elbows with cementless fixation of the porous humeral stem. At the latest follow-up, implants were removed due to infection in 3 elbows. Twenty-five elbows required ulnar component revision due to loosening of the all-polyethylene component. Two elbows required ulnar component revision due to loosening of the metal-backed component. Seven elbows required humeral component revision due to loosening of the humeral components. One elbow required revision due to dislocation. A survival analysis with revision or removal of one or both components as the end point was performed according to the Kaplan and Meier method. The overall survival rate of the prosthesis was 75.2% at 19 years. The survival of 87.0% in the metal-backed group was higher than the 74.3% in the all-polyethylene group. Loosening of the all-polyethylene ulnar component was the main reason for deterioration in the long-term outcome. We conclude that the long-term results of the Kudo type-5 total elbow arthroplasty is acceptable and cemented fixation of metal-backed ulnar component had better long-term survival than the all-polyethylene component


Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_2 | Pages 17 - 17
1 Feb 2020
Fattori A Negro ND Gunsallus K Lipman J Hotchkiss R Figgie M Wright T Pressacco M
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Introduction. Total Elbow Arthroplasty (TEA) is recognized as an effective treatment solution for patients with rheumatoid arthritis or for traumatic conditions. Current total elbow devices can be divided into linked or unlinked design. The first design usually presents a linking element (i.e. an axle) to link together the ulnar and humeral components to stabilize the joint; the second one does not present any linkage and the stability is provided by both intrinsic design constraints and the soft tissues. Convertible modular solutions allow for an intraoperative decision to link or unlink the prosthesis; the modular connections introduce however additional risks in terms of both mechanical strength and potential fatigue and fretting phenomena that may arise not only due to low demand activities loads, but also high demand (HD) ones that could be even more detrimental. The aim of this study was to assess the strength of the modular connection between the axle and the ulnar component in a novel convertible elbow prosthesis design under simulated HD and activities of daily living (ADLs) loading. Methods. A novel convertible total elbow prosthesis (LimaCorporate, IT) comprising both ulnar and humeral components that can be linked together by means of an axle, was used. Both typical ADLs and HD torques to be applied to the axle were determined based on finite element analysis (FEA); the boundary load conditions for the FEA were determined based on kinematics analysis on real patients in previous studies. The FEA resultant moment acting on the axle junction during typical ADLs (i.e. feeding with 7.2lbs weight in hand) was 3.2Nm while for HD loads (i.e. sit to stand) was 5.7 Nm. In the experimental setup, 5 axle specimens coupled with 5 ulnar bodies through a tapered connection (5 Nm assembly torque) were fixed to a torque actuator (MTS Bionix) and submerged in a saline solution (9g/l). A moment of 3.2 Nm was applied to the axle for 5M cycles through a fixture to test it under ADLs loading. After 5M cycles, the axles were analyzed with regards to fretting behavior and then re-assembled to test them against HD loading by applying 5.7 Nm for 200K cycles (corresponding to 20 years function). Results. All 5 samples withstood all 5.2M loading cycles without any mechanical failure. At the end of 5M cycles, each axle was still stable as the measured disassembly torque was 3.96 +/−0.18 Nm. Slight signs of fretting were detected on the tapered connection after 5M cycles, however they did not compromise the mechanical connection nor the stability. Discussion and Conclusions. Currently there are no reference standards that properly define protocols for biomechanical testing of elbow prostheses. In the present study, a test to mechanically assess the strength of an axle connection under both typical ADLs and HD loads was set. The connection was able to withstand the imposed conditions. In general, testing of TEA devices should include not only standard ADLs loads but also HD loads, which could be more detrimental for the long-term survivorship. For any figures or tables, please contact authors directly


Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_1 | Pages 120 - 120
1 Feb 2020
Gonzalez FQ Fattori A Lipman J Negro ND Brial C Figgie M Hotchkiss R Pressacco M Wright T
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Introduction. The interaction between the mobile components of total elbow replacements (TER) provides additional constraint to the elbow motion. Semi-constrained TER depend on a mechanical linkage to avoid dislocation and have greater constraint than unconstrained TER that rely primarily in soft tissue for joint stability. Greater constraint increases the load transfer to the implant interfaces and the stresses in the polyethylene components. Both of these phenomena are detrimental to the longevity of TER, as they may result in implant loosening and increased damage to the polyethylene components, respectively[1]. The objective of this work was to compare the constraint profile in varus-valgus and internal-external rotation and the polyethylene stresses under loads from a common daily activity between two semi-constrained TER, Coonrad/Morrey (Zimmer-Biomet) and Discovery® (DJO), and an unconstrained TER, TEMA (LimaCorporate). Methods. We developed finite element (FE) models of the three TER mechanisms. To reduce computational cost, we did not include the humeral and ulnar stems. Materials were linear-elastic for the metallic components (E. Ti6Al4V. =114.3 GPa, E. CoCr. =210 GPa, v=0.33) and linear elastic-plastic for the polyethylene components (E=618 MPa, v=0.46; S. Y. =22 MPa; S. U. =230.6 MPa; ε. U. =1.5 mm/mm). The models were meshed with linear tetrahedral elements of sizes 0.4–0.6 mm. We assumed a friction coefficient of 0.02 between metal and polyethylene. In all simulations, the ulnar component was fixed and the humeral component loaded. We computed the constraint profiles in full extension by simulating each mechanism from 8° varus to 8° valgus and from 8° internal to 8° external rotation. All other degrees-of-freedom except for flexion extension were unconstrained. Then, we identified the instant during feeding that generated the highest moments at the elbow[2], and we applied the joint forces and moments to each TER to evaluate the stresses in the polyethylene. To validate the FE results, we experimentally evaluated the constraint of the design with highest polyethylene stresses in pure internal-external rotation and compared the results against those from a FE model that reproduced the experimental setup (Fig.1-a). Results. For each design, the constraint profiles in varus-valgus (Fig.2-a) were similar to internal-external rotation (Fig.2-b). All designs showed a lax zone in which the mechanisms rotated freely and an engagement zone in which the mobile components contacted, resulting in load transfer. The laxity of the Coonrad/Morrey and the Discovery® was similar and lower than that of the TEMA. After engagement, the stiffness of the TEMA was less than that of the Discovery® and the Coonrad/Morrey. The TEMA showed the lowest polyethylene stresses of all three designs under demanding loads during feeding. Only Discovery® and Coonrad/Morrey had zones reaching permanent deformation (Fig.3). For the Coonrad/Morrey, with the highest polyethylene stresses, the experimental and computational constraint profiles were similar (Fig.1-b). Discussion. The TEMA unconstrained design transferred less moment than semi-constrained designs, reducing the burden on the implant interfaces. Moreover, the TEMA design had lower stresses in the polyethylene components due to the combination of less constraint and a lack of sharp edges on the articular surfaces. For any figures or tables, please contact the authors directly


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_29 | Pages 76 - 76
1 Aug 2013
Vrettos B Vochteloo A Roche S
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Purpose of study:. Total elbow replacement (TER) is one of the surgical options for treatment of severe haemophilic arthropathy of the elbow. There are only a few small series described in the literature. The goal of our study was to evaluate our cases and add these data to the known literature. Methods:. A retrospective analysis of a series of 8 TER's (5 patients) was performed. Patients were seen in clinic and evaluated by physical examination, a VAS score for pain, the Mayo Elbow Performance Score (MEPS, 100 points=excellent) and X-rays of the affected elbow. Mean follow-up was 91 (4–236) months, and 103 months when we excluded a patient with only 4 months follow-up. Primary diagnosis was Hemophilia type A in 4 and von Willebrand disease in 1 patient. 2 patients were positive for Hepatitis C and 3 for HIV. Mean age at primary surgery was 46.7 (31.8–63.1) years. Results:. The mean VAS score for pain improved from 7.9 to 0.5 and the mean Mayo Elbow Performance Score from 36 to 93. The arc for flexion/extension improved from 68° to 91° and from to 75° to 153° for pro- and supination. Revision surgery was performed in 3 out of 8 TER's; 1 because of loosening of the humeral component (18.7 years postop), 1 for loosening of the ulnar component (9.9 years postoperatively) and 1 due to a late deep infection, 4 years postoperatively. The last case was treated with an excision arthroplasty, the others with a revision. No replacement currently shows signs of loosening. Conclusion:. This is a small retrospective study, as are the other studies on TER in haemophilic patients. It demonstrated excellent clinical outcome and an acceptable survival rate of a TER, with a mean follow-up of 7.6 years even in this young patient population


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_15 | Pages 342 - 342
1 Mar 2013
Suenaga N Oizumi N Miyoshi N Yoshioka C
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Purpose. In total elbow arthroplasty (TEA), especially for elbows with condyle defect due to rheumatoid arthritis or trauma, determination of rotation alignment of implants is often difficult. To develop a navigation system for TEA, selecting bony landmarks that can be identified intraoperatively is important. Therefore, we developed a new roentgen free navigation system such as special alignment jigs for TEA based on CT data of normal elbows. The aim of this study was to evaluate alignments of implants after MIS-TEA using the new systems. And also, we reported that 6 bony landmarks on the elbow showed small variability in normal elbows by CT examinations and were considered to be usable as intraoperative landmarks for determining rotational position of implants last year. Especially in RA elbow, posterior aspect of humerus and ulnar aspect of proximal part of ulna were able to be identified even if there is a large bone defect that extends to the lateral or/and medial epicondyle. We used a new roentgen free navigation system in TEA with using Solar elbow from 2009. The aim of this study was to evaluate alignments of implants after MIS-TEA using the new systems by CT examinations. MATERIALS AND METHODS. For determination of alignment and anatomical landmarks to develop the jigs, 3D-CT data of 11 normal elbows was investigated. The posterior aspect of humeral shaft and ulnar aspect of proximal ulna were selected as bony landmarks. Because these can be identified intraoperatively and remain in elbows with extensive bone loss. MIS-TEA with Solar Elbow (Stryker) using these new systems were investigated with postoperative 3D-CT in 14 elbows of 13 patients. Their average age was 68.8 years old. Basic diseases were 10 rheumatoid arthritis and 4 distal humerus injuries. The alignments of humeral and ulnar component were measured on postoperative 3D-CT. RESULTS. Rotational alignment (humerus / ulna) was pronation 6.8° ± 5.7° / pronation 4.6° ± 9.1°; frontal alignment was valgus 0.1° ± 2.7° / valgus 0.1° ± 3.7°; and sagittal alignment was extension 0.6° ± 3.0° / extension 8.9° ± 2.5°. In condyle-defect group (n=5), comparable alignment with condyle-preserved group was obtained. DISCUSSION. The new systems were effective in determining intraoperative alignment even in elbows with extensive bone defect. Extension alignment of the ulna component is because the short component of Solar Elbow was placed along the center axis of the proximal ulna, which inclines in the extension direction relative to the axis of distal ulna