A common location for radius fracture is the proximal radial head. With the arm in neutral position, the fracture usually happens in the anterolateral quadrant (Lacheta et al., 2019). If traditional surgeries are not enough to induce bone stabilization and vascularization, or the fracture can be defined grade III or grade IV (Mason classification), a radial head prosthesis can be the optimal compromise between bone saving and recovering the “terrible triad”. A commercially available design of radial head prosthesis such as Antea (Adler Ortho, Milan, Italy) is characterized by flexibility in selecting the best matching size for patients and induced osteointegration thanks to the Ti-Por. ®. radial stem realized by 3D printing with laser technique (Figure 1). As demonstrated, Ti-Por. ®. push-out resistance increased 45% between 8 −12 weeks after implantation, hence confirming the ideal bone-osteointegration. Additional features of Antea are: bipolarity, modularity, TiN coating, radiolucency, hypoallergenic, 10° self-aligning. The osteointegration is of paramount importance for radius, in fact the literature is unfortunately reporting several clinical cases for which the fracture of the prosthesis happened after bone-resorption. Even if related to an uncommon activity, the combination of mechanical resistance provided by the prosthesis and the stabilization due to the osteointegration should cover also accidental movements. Based upon Lacheta et al. (2019), after axial compression-load until radii failure, all native specimens survived a compression-load of 500N, while the failure happened for a mean compression force of 2560N. The aim of this research study was to test the mechanical resistance of a radial head prosthesis obtained by 3D printing. In detail, a finite element analysis (FEA) was used to understand the mechanical resistance of the core of the prosthesis and the potential bone fracture induced in the radius with simulated bone- resorption (Figure 2a). The critical level was estimated at the height for which the thickness of the core is the minimum (Figure 2b). Considered boundary conditions:. - Full-length prosthesis plus radius out of the cement block equal to 60mm (Figure 2a);. - Bone inside the cement equal to 60mm (Figure 2b);. - Load inclined 10° epiphysiary component (Figure 2c);. - Radius with physiological or osteoporotic bone conditions;. - Load (concentrated in the sphere simulating full transmission from the articulation) of 500N or 1300N or 2560N. Figure 3 shows the results in terms of maximum stress on the core of the prosthesis and the risk of fracture (Schileo et al., 2008). According to the obtained results, the radial head prosthesis shows promising mechanical resistance despite of the simulated bone-resorption for all applied loads except for 2560N. The estimated mechanical limit for the material in use is 200MPa. The risk of fracture is in agreement with the experimental findings (Lacheta et al. (2019)), in fact bone starts to fail for the minimum reported failure load, but only for osteoporotic conditions. The presented FEA aimed at investigating the behavior of a femoral head prostheses made by 3D printing with simulated bone-resorption. The prosthesis shows to be a skilled solution even during accidental loads. For any figures or tables, please contact the authors directly

Background. Comminuted radial head fractures are challenging to treat with open reduction and internal fixation. Complicating matters further, radial head fractures are often associated with other elbow fractures and soft tissue injuries. Radial head arthroplasty is a favorable technique for the treatment of radial head fractures. The purpose of this study was to evaluate the functional outcomes of radial head arthroplasty using Modular Pyrocarbon radial head prosthesis in patients with unreconstructible radial head fractures. Methods. This single surgeon, single centre study retrospectively reviewed the functional and radiological outcomes of 21 consecutive patients requiring radial head arthroplasty for unreconstructible radial head fractures between July 2003 and July 2009. Patients were at least one year post-op and completed a Short-Form 36 (SF-36) questionnaire, the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire, and the Mayo Elbow Performance Index (MEPI). These patients were independently physically examined and their post-operative radiographs were independently reviewed. Results. 21 patients (9 males and 12 females) were reviewed at a minimum of 12 months follow-up. The mean DASH score was 10.8 (0-34.1), the mean SF-36 physical score was 76.9 (35-96), the mean SF-36 mental score was 83.8 (60-94), and their MEPI score was 86.4 (70-100). Patients maintained 90% of their grip strength in their injured arm when compared to their un-injured arm and had 17. o. of fixed flexion in the affected arm. Radiologically, 14 cases had some degree of post-traumatic osteoarthritis, 12 cases had evidence of heterotrophic ossification, 5 had some evidence of periprosthetic lucency and 3 of our cases were radiologically but not functionally ‘overstuffed’. Conclusion. Radial Head Arthroplasty with Pyrocarbon Radial Head Prosthesis is a safe and effective option when treating unreconstructable comminuted radial head fractures yielding good functional and radiological outcomes and remains the treatment option of choice at our institution

Essex-Lopresti injuries are often unrecognized acutely with resulting debilitating adverse effects. Persistent axial forearm instability may affect load transmission at both the elbow and wrist, resulting in significant pain. In the setting of both acute and chronic injuries metallic radial head arthroplasty has been advocated, however there is little information regarding their outcome. The purpose of this study was to assess the efficacy of a radial head arthroplasty to address both acute and chronic Essex-Lopresti type injuries. A retrospective review from 2006 to 2016 identified 11 Essex-Lopresti type injuries at a mean follow-up of 18 months. Five were diagnosed and treated acutely at a mean of 11 days (range, 8 to 19 days) from injury, while 6 were treated in a delayed fashion at a mean of 1.9 years (range, 2.7 months to 6.2 years) from injury with a mean 1.5 (range, 0 to 4) prior procedures. The cohort included 10 males with a mean age was 44.5 years (range, 28 to 71 years). A smooth stem, modular radial head arthroplasty was used in all cases. Outcomes included range of motion and radiographic findings such as ulnar variance, capitellar erosion, implant positioning and implant lucency using a modification of the method described by Gruen. Reoperations, including the need for ulnar shortening osteotomy, were also recorded. Three patients in each group (55%) reported persistent wrist pain. The mean ulnar variance improved from +5 mm (range, 1.8 to 7 mm) to +3.7 mm (range, 1 to 6.3 mm) at the time of final follow-up or prior to reoperation. Three (50%) patients in the chronic group underwent a staged ulnar shortening osteotomy (USO) to correct residual ulnar positive variance and to manage residual wrist pain. There were no reoperations in the acute group. Following USO, the ulnar variance in those three cases improved further to +3.5, +2.1, and −1.1 mm. No radial head prostheses required removal. Capitellar erosion was noted in five (45%) elbows, and was rated severe in one, moderate in two, and mild in two. Lucency about the radial head prosthesis stem was noted in eight (73%) cases, and rated as severe in 2 (18%), based on Gruen zones. Treatment of acute and chronic Essex-Lopresti lesions with radial head arthroplasty often results in persistent wrist pain. In the chronic setting, a planned USO was often necessary to restore axial forearm stability after radial head arthroplasty. Essex-Lopresti lesions represent a rare clinical entity that are difficult treat, particularly in the chronic setting. Early recognition and management with a smooth stem modular radial head arthroplasty may provide improved outcomes compared to chronic reconstruction

INTRODUCTION:. Radial head arthroplasty is a reliable procedure with good functional outcomes when faced with irreparable radial head fractures. Since the first attempt at arthroplasty by Speed in 1941, there have been a variety of different designs created for radial head prostheses. There has been considerable recent interest in bipolar radial head components. However, to date, there have been few biomechanical studies comparing bipolar components to their monopolar counterparts. We examine the effects of alteration of axial length of the radial head prosthesis and force conveyed at the radiocapitellar joint in a head-to-head comparison of bipolar implants to monopolar implants. METHODS:. Sixteen fresh-frozen, sided cadaveric arms were utilized. Radial heads were resected and either a monopolar, rigid, metal radial head prosthesis (Solar, Stryker, Mahwah, NJ) was implanted or a bipolar metal prosthesis used (Katalyst, Integra, Plainsboro, NJ). Adjustments of radial head length were made in 2 mm increments using radiolucent washers to create an understuffed (−2), neutral (0), and overstuffed (+2, +4) effect, see Fig. 1. Forearms were cyclically loaded in compression from 13N to 130N with the forearm in neutral. Radiocapitellar forces were measured using Tekscan (Tekscan, Inc., Boston, MA) pressure sensors with radial head length set at −2 mm, 0, +2 mm and +4 mm and comparisons were made with the neutral (0) radial head, see Fig. 2. Multivariant ANOVA with Tukey's HSD correction was used for statistical analysis. RESULTS:. Radiocapitellar average peak pressures using monopolar and bipolar radial heads in arms that were understuffed (−2 mm), were 0.54 and 0.39 MPa, respectively; neutral (0 mm), 0.68 and 0.36 MPa; and overstuffed (+2 mm), 0.44 and 0.39 MPa; (+4 mm), 0.48 and 0.40 MPa, respectively. There was a noticeable stepwise increase in force transmitted with progressive radial head lengthening regardless of implant design. Radiocapitellar forces were almost 1.5 times greater with monopolar radial head overstuffing (+4) compared to neutral (0) while they essentially doubled with bipolar radial head overstuffing (+4) compared to neutral (0) (p < 0.01). The average change in measured values for the monopolar prostheses compared to the bipolar prostheses in the same arm are shown in Figure 2. DISCUSSION:. Progressive radial head lengthening regardless of implant design was associated with a stepwise increase in radiocapitellar joint force. Radiocapitellar forces where notably lower with the bipolar radial head when compared to their monopolar counterparts. This may in part be due to the bipolar design which allows for increased play at the radiocapitellar junction., see Fig. 3. Significance: Sizing and selection of the radial head implant plays a critical role in restoring native radiocapitellar loads and may prevent accelerated wear at the radiocapitellar joint after radial head arthroplasty. Figure 1 – Radial head length was controlled by applying 2 mm thick washers beneath the head, shown here with a monopolar prosthesis. Figure 2 – The bipolar radial head transmitted less force, greater contact area and lower peak pressures than with monopolar prostheses. Figure 3 – This radiographic image shows the potential for the bipolar radial head implant to realign to the joint under load

The clinical case refers to a male patient, 34 years old, admitted at the Emergency Department after a fall of 2 meters. Of that trauma, resulted an exposed Monteggia fracture type III – Gustillo & Anderson IIA – on his left arm. With this work, the authors intend to describe the evolution of the patient's clinical condition, as well as the surgical procedures he was submitted to. The authors used the patient's records from Hospital's archives, namely from the Emergency Department, Operating Room, Infirmary and Consultation, and also the diagnostic exams performed throughout the patient's clinical evolution. The clinical case began in December 2011, when the patient suffered a fall of 2 meters in his workplace. From the evaluation in the Emergency Department, it was concluded that the patient presented, at the left forearm, an exposed Monteggia type III fracture – Gustillo & Anderson IIA – combined with a comminuted fracture of the radial head. At the admission day, the wound site was thoroughly rinsed, the fracture was reduced and immobilized with an above-the-elbow cast, and antibiotics were initiated. Six days after admission, the patient was submitted to open reduction with internal fixation with plate and screws of the fracture of the ulna and radial head arthroplasty. The postoperative period was uneventful. Two months after the surgical procedure, inflammatory signals appeared with purulent secretion in the ulnar suture. Accordingly, the patient was submitted to fistulectomy, rinsing of the surgical site and a cycle of antibiotics with Vancomycin, directed to the S. aureus isolated from the purulent secretion. The clinical evolution was unfavorable, leading to the appearance of a metaphyseal pseudarthrosis or the ulna and dislocation of the radial head prosthesis. The previously implanted material was therefore removed, 4 months after the traumatic event; at the same time an external fixation device was applied and the first part of a Masquelet Technique was conducted. The second part of the aforementioned procedure was carried out in December 2012. The patient was discharged from the consultation after a 2 years follow-up, with a range of motion of the left elbow acceptable for his daily living activities. In spite of the multiple surgical rinsing procedures and directed antibiotics, the development of a metaphyseal pseudarthrosis of the ulna was inevitable. This clinical case illustrates how the Masquelet Technique presents itself as a good solution for the cases of non-union of fractures in the context of infection

Purpose. Assess and report the functional and post-operative outcomes of complex acute radial head fractures with elbow instability treated by arthroplasty using an uncemented modular anatomic prosthesis. Methods. Over a 3-year period (2007–2010), 21 patients (mean age 51.9 years) were treated primarily with modular radial head arthroplasty (mean follow up of 27.1 months). Data was collected retrospectively using clinical notes, operation documentation and prospectively using validated scoring systems namely the Oxford Elbow Index, Quick DASH and the Mayo Elbow Performance Score. Associated elbow fractures, ligamentous injury and short to mid term post-operative outcomes including radiographic assessment were recorded. Results. The mean Oxford Elbow Score was 34.80 (range 20–48). The mean Quick Dash score was 26.01 (range 0–68.2). The Mayo Performance score showed 6 scored excellent, 5 scored good, 3 scored fair and 2 scored poor. Regarding post-operative outcomes, 1 patient had a radial head dislocation, 1 patient had prosthesis removal for ongoing pain and 1 patient had a total elbow replacement due to associated proximal ulna fracture non-union. 11 patients had an associated ligamentous injury of which 6 had an associated coronoid fracture. Of note, 7 patient's radiographs showed early signs of implant loosening; this was mainly asymptomatic. Conclusions. With regard to complex radial head fractures with elbow instability, patient outcome measures showed good functionality and overall patient satisfaction despite radiographic evidence of loosening. Post-operative complication rates were low. These findings support the use of this radial head prosthesis in arthoplasty surgery for the treatment of complex acute radial head fractures with elbow instability

To study the surgical outcome of multi-fragmentary, un-reconstructable radial head fractures managed acutely by a radial head prosthetic replacement, we retrospectively reviewed nineteen radial head fractures that were treated acutely with a radial head replacement, over a four-year period in three district general hospitals. Nineteen patients were clinically and radiologically assessed for this study. Functional assessment was performed with the Mayo elbow performance score (MEPS). No patient achieved full functional range of motion. The average range of flexion was 110° (range 80° to 120°), average extension deficit of 35° (range 30° to 45°), average pronation was 35° (range 0° to 65°), and average supination was 50° (range 30° to 85°). Complications included implant removal due to loosening (n=1), elbow stiffness (n=2), and instability (n=1), the latter case requiring a revision of the radial head prosthesis. Some degree of persistent discomfort was noticed in all cases. Five patients were tolerant of the final functional outcome. The average Mayo elbow score was 68/100 (range 55 to 80). One patient had an intra-operative fracture of the radial metaphysis during insertion of the implant. Conclusions. Radial head replacement in general orthopaedic, low volume practice failed to achieve satisfactory results. Contrary to popular belief, it is a technically demanding operation, for which surveillance should be continued for a minimum of one year. Strict indications for prosthetic replacement should be followed and implant selection has yet to be proven to make a significant positive contribution. Our review highlights the need for a stricter adherence to indications; surgery should not be under-estimated and devolved to trainees, and our understanding of the radial axis of the elbow and forearm remains relatively rudimentary

Purpose. Radial head implant over-lengthening, a common cause of capitellar wear and clinical failure, is difficult to diagnose using radiographs of the injured elbow. The purpose of this study was to determine if a novel measurement technique based on contralateral elbow radiographs, termed the RACER method, could be used to accurately estimate the magnitude of radial head implant over-lengthening. Part I of this study examined the side-to-side consistency of radiographic landmarks used in the measurement technique. Part II of this study validated the technique using simulated radial head implant over-lengthening in a cadaveric model. Method. Part I: A side-to-side comparison of elbow joint dimensions was performed in 50 patients (100 radiographs). Part II: Radial head prostheses of varying lengths (0,+2mm,+4mm,+6mm,+8mm) were implanted in 4 paired cadaveric specimens (8 elbows). Radiographs were obtained and measurements were performed by 2 examiners blinded to implant size to determine if contralateral radiographs could diagnose and provide a valid estimate of the magnitude of implant over-lengthening. Intra and inter-rater reliability was determined. Results. No significant side-to-side differences (p>0.2) in radiographic measurements were identified between paired elbows. The RACER measurement technique using contralateral radiographs was successful in predicting the implant size (1mm) in 104 of 120 (87%) of scenarios tested. The sensitivity of the technique, the ability of the test to correctly identify over-lengthening when it was present within 1mm, was 98%. The intra-rater agreement for a single orthopaedic surgeon measuring on 2 separate occasions was excellent (ICC>0.90). The inter-rater agreement between two separate surgeons was also excellent, with the 95% lower confidence interval exceeding 0.90 in all cases. Conclusion. A novel measurement technique based on contralateral elbow radiographs can be used to diagnose and calculate the magnitude of radial head implant over-lengthening. Clinical Significance: Implantation of an incorrectly sized radial head prosthesis is not uncommon. The described technique can be used to effectively diagnose and determine the magnitude of over-lengthening