We measured the tension in the interosseous membrane in six cadaveric forearms using an in vitro forearm testing system with the native radial head, after excision of the radial head and after metallic radial head replacement. The tension almost doubled after excision of the radial head during simulated rotation of the forearm (p = 0.007). There was no significant difference in tension in the interosseous membrane between the native and radial head replacement states (p = 0.09). Maximal tension occurred in neutral rotation with both the native and the replaced radial head, but in pronation if the radial head was excised. Under an increasing axial load and with the forearm in a fixed position, the rate of increase in tension in the interosseous membrane was greater when the radial head was excised than for the native radial head or replacement states (p = 0.02). As there was no difference in tension between the native and radial head replacement states, a radial head replacement should provide a normal healing environment for the interosseous membrane after injury or following its reconstruction. Load sharing between the radius and ulna becomes normal after radial head Replacement. As excision of the radial head significantly increased the tension in the interosseous membrane it may potentially lead to its attritional failure over time. Cite this article: Bone Joint J 2013;95-B:1383–7

Aims. In patients with a failed radial head arthroplasty (RHA), simple removal of the implant is an option. However, there is little information in the literature about the outcome of this procedure. The aim of this study was to review the mid-term clinical and radiological results, and the rate of complications and removal of the implant, in patients whose initial RHA was undertaken acutely for trauma involving the elbow. Methods. A total of 11 patients in whom removal of a RHA without reimplantation was undertaken as a revision procedure were reviewed at a mean follow-up of 8.4 years (6 to 11). The range of motion (ROM) and stability of the elbow were recorded. Pain was assessed using a visual analogue scale (VAS). The functional outcome was assessed using the Mayo Elbow Performance Score (MEPS), the Oxford Elbow Score (OES), and the Disabilities of the Arm, Shoulder and Hand questionnaire (DASH). Radiological examination included the assessment of heterotopic ossification (HO), implant loosening, capitellar erosion, overlengthening, and osteoarthritis. Complications and the rate of further surgery were also recorded. Results. The indications for removal of the implant were stiffness in five patients, aseptic loosening in five, and pain attributed to the RHA in three. The mean time interval between RHA for trauma to removal was ten months (7 to 21). Preoperatively, three patients had overlengthening of the implant, three had capitellar erosion, six had HO, and four had radiological evidence of loosening. At the final follow-up, the mean the flexion-extension arc improved significantly by 38.2° (95% CI 20 to 59; p = 0.002) and the mean arc of prono-supination improved significantly by 20° (95% CI 0 to 72.5; p = 0.035). The mean pain VAS score improved significantly by 3.5 (95% CI 2 to 5.5; p = 0.004). The mean MEPS improved significantly by 27.5 (95% CI 17.5 to 42.5; p = 0.002). The mean OES improved significantly by 9 (95% CI 2.5 to 14; p = 0.012), and the mean DASH score improved significantly by 23.5 (95% CI 7.5 to 31.6; p = 0.012). Ten patients (91%) had HO and osteoarthritis. Two patients underwent further surgery due to stiffness and pain, respectively. Conclusion. Simple removal of the implant at revision surgery following a failed RHA introduced following trauma provides satisfactory mid-term results with an acceptable risk of complications. Osteoarthritis, instability, and radioulnar impingement were not problems in this series. Cite this article: Bone Joint J 2024;106-B(11):1327–1332

Aims. The aim of this study was to evaluate the kinematics of the elbow following increasing length of the radius with implantation of radial head arthroplasties (RHAs) using dynamic radiostereometry (dRSA). Methods. Eight human donor arms were examined by dRSA during motor-controlled flexion and extension of the elbow with the forearm in an unloaded neutral position, and in pronation and supination with and without a 10 N valgus or varus load, respectively. The elbows were examined before and after RHA with stem lengths of anatomical size, + 2 mm, and + 4 mm. The ligaments were maintained intact by using a step-cut lateral humeral epicondylar osteotomy, allowing the RHAs to be repeatedly exchanged. Bone models were obtained from CT scans, and specialized software was used to match these models with the dRSA recordings. The flexion kinematics of the elbow were described using anatomical coordinate systems to define translations and rotations with six degrees of freedom. Results. The greatest kinematic changes in the elbows were seen with the longest, + 4 mm, implant, which imposed a mean joint distraction of 2.8 mm in the radiohumeral joint and of 1.1 mm in the ulnohumeral joint, an increased mean varus angle of up to 2.4° for both the radius and the ulna, a mean shift of the radius of 2.0 mm in the ulnar direction, and a mean shift of the ulna of 1.0 mm posteriorly. Conclusion. The kinematics of the elbow deviated increasingly from those of the native joint with a 2 mm to a 4 mm lengthening of the radius. This confirms the importance of restoring the natural length of the radius when undertaking RHA. Cite this article: Bone Joint J 2024;106-B(10):1165–1175

Aims. The aim of this study was to analyze how proximal radial neck resorption (PRNR) starts and progresses radiologically in two types of press-fit radial head arthroplasties (RHAs), and to investigate its clinical relevance. Methods. A total of 97 patients with RHA were analyzed: 56 received a bipolar RHA (Group 1) while 41 received an anatomical implant (Group 2). Radiographs were performed postoperatively and after three, six, nine, and 12 weeks, six, nine, 12, 18, and 24 months, and annually thereafter. PRNR was measured in all radiographs in the four radial neck quadrants. The Mayo Elbow Performance Score (MEPS), the abbreviated version of the Disabilities of the Arm, Shoulder, and Hand questionnaire (QuickDASH), and the patient-assessed American Shoulder and Elbow Surgeons score - Elbow (pASES-E) were used for the clinical assessment. Radiological signs of implant loosening were investigated. Results. The mean follow-up was six years (2 to 14). PRNR started after a mean of 7.5 weeks (SD 2.1) and progressed significantly during the first two years, by the end of which the bone resorption stabilized. PRNR was detected in 81% (n = 45) of patients in Group 1 and 88% (n = 36) in Group 2. The final mean PRNR was 3.0 mm (SD 2.3) in Group 1 and 3.7 mm (SD 2.5) in Group 2. The mean MEPS, QuickDASH, and pASES-E were 95.9 (SD 11.5), 4.4 (SD 9.2), and 94.8 (SD 10.9) in Group 1 and 92.2 (SD 16.2), 9.9 (SD 21.5), and 90.8 (SD 15) in Group 2, respectively. No significant differences were observed between groups in the clinical and radiological outcomes. No correlations were found between PRNR and the clinical results. Conclusion. PRNR after press-fit RHA is a common radiological finding that develops in the first 24 months before stabilizing definitively. PRNR does not affect the clinical results or implant survival in the mid term. Cite this article: Bone Joint J 2023;105-B(8):905–911

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

Radial head fractures are among the most common fractures around the elbow. Radial head arthroplasty is one of the surgical treatment options after complex radial head fractures. This surgery is usually done under general anaesthesia. However, there is a recent anaesthetic technique - wide awake local anaesthesia no tourniquet (WALANT) - that has proven useful in different surgical settings, such as in distal radius or olecranon fractures. It allows a good haemostatic control without the use of a tourniquet and allows the patient to actively collaborate during the surgical procedure. Furthermore, there are no side effects or complications caused by the general anaesthesia and there's an earlier patient discharge. The authors present the case of a seventy-six-year-old woman who presented to the emergency department after a fall from standing height with direct trauma to the left elbow. The radiological examination revealed a complete intra-articular comminuted fracture of the radial head (Mason III). Clinical management: The patient was submitted to surgery with radial head arthroplasty, using WALANT. The surgery was successfully completed without pain. There were no intra or immediate post-operative complications and the patient was discharged on the same day. Six weeks after surgery, the patient had almost full range of motion and was very pleased with the functional outcome, with no limitations on her activities of daily living. The use of WALANT has been expanded beyond the hand and wrist surgery. It is a safe and simple option for patients at high risk of general anaesthesia, allowing similar surgical outcomes without the intraoperative and postoperative complications of general anaesthesia and permitting an earlier hospital discharge. Furthermore, it allows the patient to actively collaborate during the surgery, providing the surgeons the opportunity to evaluate active mobility and stability, permitting final corrections before closing the incision

Aims. It has been hypothesized that proximal radial neck resorption (PRNR) following press-fit radial head arthroplasty (RHA) is due to stress-shielding. We compared two different press-fit stems by means of radiographs to investigate whether the shape and size of the stems are correlated with the degree of PRNR. Methods. The radiographs of 52 RHAs were analyzed both at 14 days postoperatively and after two years. A cylindrical stem and a conical stem were implanted in 22 patients (group 1) and 30 patients (group 2), respectively. The PRNR was measured in the four quadrants of the radial neck and the degree of stem filling was calculated by analyzing the ratio between the prosthetic stem diameter (PSD) and the medullary canal diameter (MCD) at the proximal portion of the stem (level A), halfway along the stem length (level B), and distally at the stem tip (level C). Results. Overall, 50 of the 52 patients displayed PRNR. The mean PRNR observed was 3.9 mm (0 to 7.4). The degree of endomedullary stem filling at levels A, B, and C was 96%, 90%, and 68% in group 1, and 96%, 72%, and 57%, in group 2, with differences being significant at levels B (p < 0.001) and C (p < 0.001). No significant correlations emerged between the severity of PRNR and the three stem/canal ratios either within each group or between the groups. Conclusion. PRNR in press-fit RHA appears to be independent of the shape and size of the stems. Other causes besides stem design should be investigated to explain completely this phenomenon. Cite this article: Bone Joint J 2021;103-B(3):530–535

There is little information available at present regarding the mechanisms of failure of modern metallic radial head implants. Between 1998 and 2008, 44 consecutive patients (47 elbows) underwent removal of a failed metallic radial head replacement. In 13 patients (13 elbows) the initial operation had been undertaken within one week of a fracture of the radial head, at one to six weeks in seven patients (seven elbows) and more than six weeks (mean of 2.5 years (2 to 65 months)) in 22 patients (25 elbows). In the remaining two elbows the replacement was inserted for non-traumatic reasons. The most common indication for further surgery was painful loosening (31 elbows). Revision was undertaken for stiffness in 18 elbows, instability in nine, and deep infection in two. There were signs of over-lengthening of the radius in 11 elbows. Degenerative changes were found in all but one. Only three loose implants had been fixed with cement. Instability was not identified in any of the bipolar implants

The aim of this study was to report the outcome of radial head replacement for complex fractures of the radial head, and determine any risk factors for prosthesis removal or revision. We identified 119 patients who were managed acutely using primary radial head replacement for an unstable fracture of the radial head over a 15-year period. Demographic data, fracture classification, management, complications and subsequent surgeries were recorded following retrospective clinical record review. There were 105 (88%) patients with a mean age of 50 yrs (16–93) and 54% (n=57) were female. There were 95 (91%) radial head fractures and 96% were a Mason type 3 or 4 injury. There were 98 associated injuries in 70 patients (67%), with an associated coronoid fracture (n=29, 28%) most frequent. All implants were uncemented monopolar prostheses, with 86% metallic and 14% silastic. At a mean short-term follow-up of 1 year (range, 0.1–5.5; n=87) the mean Broberg and Morrey score was 80 (range, 40–99), with 49.5% achieving an excellent or good outcome. At a final mean review of 6.7 yrs (1.8–17.8), 29 (27%) patients had undergone revision (n=3) or removal (n=26) of the prosthesis. Independent risk factors of prosthesis removal or revision were silastic implant type (p=0.010) and younger age (p=0.015). This is the largest series in the literature documenting the outcome following radial head replacement for complex fractures of the radial head. We have demonstrated a high rate of removal or revision for all implants, with younger patients and silastic implants independent risk factors

Purpose: To review the clinical outcome of patients who have had complex radial head fractures managed with titanium radial head replacement. Methods: There were 17 patients who had insertion of the radial head replacement. The indications for the prosthesis included acute Mason type III fracture which could not be stabilised satisfactorily with internal fixation. Other indications included delayed presentation including previously failed treatment. Patients were managed with radial head excision and insertion of the Wright Medical titanium radial head replacement. The lateral ligamentous complex was stabilised. A back slab was applied for a period of one week and then the elbow mobilised. The patients were followed up for a minimum of one year. The Mayo elbow performance index was used. Results: There were 7 patients with acute injuries of which 6 had associated injuries such as dislocation or coronoid process fracture. 6 of these patients had an excellent result and 1 had a good result. There were 9 patients with a delayed insertion of the radial head replacement. There were 3 patients who had an isolated radial head fracture and 6 patients with associated injuries, there were 2 excellent, 3 fair and 4 poor. Three of the 4 poor results had associated capitellar chondral injury. Two patients with fair results had other significant pathology in the upper limb. In the delayed presentation group the average flexion arc improved from 78 degrees to 102 degrees and the pro-supination improved from 117 degrees to 142 degrees. The average level of satisfaction on a visual analog score was 92 per cent. Conclusion: Patients who present with acute complex radial head fractures (including associated injuries), the results of radial head replacement are generally excellent. If there are significant associated injuries and a delay in presentation, then the outcome is often only fair. However, this group of patients have improvement in their pain, level of satisfaction and range of motion. Associated capitellar damage is a poor prognostic indicator

Introduction: Radial Head Arthroplasty is considered the treatment of choice for unreconstructable radial head fractures. Short-term results in the current literatue are promising. Due to the lack of long-term results, radial head arthroplasty is looked at critically by many surgeons. In our the study we provide the 8.4 years results after treatment with the floating radial head prosthesis by Judet (Tornier, France). Methods: In our department 19 patients were treated with bipolar radial head arthroplasty between 1997 and 2001. 11 prostheses were implantated primary and 6 secondary. The other two were implanted because of a loosening of a prior implanted prosthesis and one after resection of a vast chondrosarcoma. 12 of these patients − 10 men and 2 women – were now examined retrospectively after 101 months (78–132). Results: 6 Patients were treated primary, 5 secondary and one was treated because of a vast chondrosarcoma. There were 5 proximal ulna fractures and 8 processus coronoideus fractures as concomitant injuries of the elbow. Following complications were seen: 2 dislocations, 2 capitellar erosions and 4 cases of heterotopic ossifications. According to the Mayo Elbow Performance Score 4 patients achieved an excellent result, 7 a good, and one a satisfactory result. The mean DASH was 13.7 (0–44). No differences were seen between primary and secondary implantation. The flexion arc was 123° (110–140°), the extension deficit was 20° (0–40°), pronation 61° (30–90°) and supination 62° (40–90°). Conclusion: Our 8.4 years results show that radial head arthroplasty with Judet’s bipolar prosthesis leads to mostly excellent and good – subjective as well as objective – results

Purpose: Unrepairable fractures of the radial head are often treated with radial head arthroplasty. Insertion of a radial head prosthesis that is too thick, or overstuffed, is believed to be a common complication that may result in pain, arthrosis, capitellar wear and decreased elbow range of motion. The purpose of this study was to develop guidelines for determining the appropriate thickness of radial head implants. We hypothesized that. radiographic incongruity of the medial facet of the ulnohumeral joint and that. the macroscopic presence of a gap in the lateral facet of the ulnohumeral joint correlate with radial head overstuffing. Method: Six human cadaveric upper extremities were used to evaluate the clinical and radiographic effects of overstuffing of a radial head arthroplasty. Each specimen received an anatomic radial head replacement and then underwent overstuffing with +2 mm, +4 mm, +6 mm and +8 mm lengths. Gross lateral ulnohumeral joint spaces were measured, and anteroposterior radiographs were taken of the elbow from which radiographic medial and lateral ulnohumeral joint spaces were measured. Results: Intraoperative gapping of the lateral ulnohumeral facet was shown to be highly reliable for detecting radial head overstuffing, increasing from a mean of 0.0 mm at standard length to 1.0 mm with 2 mm overstuffing (p < 0.05). Radiographically, the congruity of the lateral ulnohumeral facet was significantly different with 2 mm of overstuffing as compared to the anatomic length (p < 0.05). The congruity of the medial ulnohumeral facet only became significantly different with +6 mm of overstuffing as compared to the anatomic length (p < 0.05). Conclusion: Radiographic incongruity of the medial facet of the ulnohumeral joint was an unreliable indicator of radial head overstuffing. Radiographic gapping of the lateral ulnohumeral facet demonstrated sufficient sensitivity to diagnose radial head overstuffing when compare to the standard length implant radiographs. Visual gapping of the lateral ulnohumeral facet on the cadaver specimens reliably indicated radial head overstuffing and should be a useful anatomic feature to assess intraoperatively

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

Introduction and Aims: To evaluate the results of radial head replacement in the primary management of radial head fractures. The recommended indications for prosthetic radial head replacement include unreconstructable Mason 3 fractures associated with ligament disruption or axial forearm instability. Method: We retrospectively reviewed all radial head fractures that were treated with a radial head replacement, over a four-year period, in two district general hospitals. All seven patients were finally assessed specifically for this study, either in person or by telephone/ postal questionnaire, with final radiographs obtained for this study. Results: Routine clinical follow-up was three months, following which the patient was discharged. No patient achieved full functional range of motion. The average range of flexion was 110 degrees (range 80 to 120 degrees), average extension deficit of 35 degrees (range 30 to 45 degrees), average pronation was 35 degrees (range 0 to 65 degrees), and average supination was 50 degrees (range 30 to 85 degrees). Three patients required implant removal due to loosening (1/3), elbow stiffness (2/3), and instability (1/3), the latter case requiring a revision of the radial head prosthesis. Persistent discomfort was noticed in all cases. Four patients were tolerant of the final functional outcome, although the average Mayo elbow score was 78/100 (range 55 to 80). Conclusion: 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

Purpose: Radial head replacement with a prosthesis that is too thick has been reported to be associated with stiffness, pain and capitellar wear. Radiographic widening of the lateral ulnohumeral joint following radial head replacement has been used as a criterion to diagnose overstuffing of the radiocapitellar joint. The purpose of this study was to show that widening of the lateral ulnohumeral joint is a normal anatomic variant and therefore cannot be used conclusively to diagnose radiocapitellar joint overstuffing. Methods: Fifty normal standardized anteroposterior elbow radiographs from 50 patients with a mean age of 48 years were reviewed to evaluate variations in the joint space between the medial and lateral facets of the ulnohumeral joint. Using computer software at 4x magnification (GE, Fairfield, CT), two lines were drawn perpendicular to the lateral ulnohumeral joint and two lines perpendicular to the medial ulnohumeral joint. The difference in length of these two lines was used to assess how parallel the lateral and medial joint spaces are. The lengths of the two lines were averaged to compare lateral joint space thickness to medial joint space thickness. Results: The width of the lateral ulnohumeral joint space (3.6mm & #61617; 0.8mm) was greater than the medial ulnohumeral joint space (2.8mm & #61617; 0.5mm) (p< 0.001). The lengths of the two medial joint space perpendicular lines were similar (p> 0.05), indicating the medial joint space is normally parallel. The lengths of the lateral joint space perpendicular lines were greater laterally (p= 0.02), indicating the lateral joint is not normally parallel. Conclusions: The lateral ulnohumeral joint space is often wider than the medial ulnohumeral joint space on an anteroposteror radiograph of the normal elbow. While the medial ulnohumeral joint space is usually parallel, the lateral ulnohumeral joint space may be non-parallel and wider laterally, therefore, lateral joint space widening is not a reliable indicator of radiocapitellar joint overstuffing. A non-parallel medial ulnohumeral joint space may be suggestive of possible overstuffing of a radial head arthroplasty, however, comparison radiographs of the uninjured elbow is likely the best investigation to consider when overstuffing is suspected

The evidence for treatment of acute complex radial head fractures with radial head replacement (RHR) predominantly comprises short to mid-term follow-up. This study describes the complications and long-term patient reported outcomes following RHR. From a single-centre trauma database we retrospectively identified 119 patients over a 16-year period who underwent primary RHR for an acute complex radial head fracture. We reviewed electronic records to document post-operative complications, including prosthesis revision and removal. Patients were contacted to confirm complications and long-term patient reported outcomes. The primary outcome measure was the QuickDash (QD). The mean age at injury was 50 years (16–94) and 63 (53%) were female. Most implants were uncemented ‘loose-fit’ monopolar prostheses; 86% (n=102) were metallic and 14% (n=17) silastic. Thirty patients (25%) required revision surgery (n=3) or prosthesis removal (n=27). Five patients underwent arthrolysis and there were four cases of infection. In the long-term, 80% (80/100; 19 deceased) were contacted at a mean of 12 years (7.5–23.5). The median QD was 6.8 (IQR, 16.8), the median EQ-5D was 0.8 (IQR, 0.6) and the median Oxford Elbow Score was 46 (IQR, 7). Overall satisfaction was high with a mean of 9.4/10 (2–10). There was no significant difference in any outcome measure for those patients requiring revision or removal surgery (all p>0.05). This is the largest series in the literature documenting the long-term patient reported outcome after RHR. Despite a quarter of patients requiring further surgery, RHR is supported by positive long-term results for the treatment of complex radial head fractures

Aims: The purpose of our study was to determine the radiographic anatomy of the proximal radius in three different views in order to identify that position, which has the smallest value for the angle between the axis of forearm rotation (AFR) and the radial neck axis (RNA). It is our hypothesis that such a position should offer the optimal situation for the radial neck cut in radial head replacement, as it will approximate the normal biomechanical axis of forearm rotation. Methods: Anteroposterior (AP) and lateral radiographs of 20 healthy volunteersñ forearms were taken in three views (full supination, neutral, full pronation). Radial head maximum diameter and angular measurements between the axis of forearm rotation (AFR) and the radial neck axis (RNA) were made utilizing digital calipers. Results: Repeated-measures analysis of variance (ANOVA) revealed a statistically signiþcant difference between the three AP groups, with supination having the smallest values (p< 0.0001), but not for the lateral groups (p=0.128). Comparison of the AFR-RNA angle between the AP supinated position and the three lateral views revealed a statistically signiþcant difference among all the pairs with the AP supinated position having the smallest values. Conclusions: The RNA most closely approximates the AFR with the forearm in the supinated position. To best approximate the native AFR during radial head replacement, the cut should be made perpendicular to the neck axis with the elbow extended and the forearm in the supinated position

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

Background. Radial head arthroplasty (RHA) is a popular method of treatment for complex fractures of the radial head. The purpose of this study was to investigate patient outcomes and radiographic findings associated with a single anatomical monopolar press-fit radial head system commonly used for the treatment of radial head fractures. Methods. A retrospective review of prospectively collected data was performed for a consecutive series of patients treated with RHA between November 2007 and April 2014. Patients with a minimum of 12-month follow-up were included. Most recent radiographs were evaluated for loosening, stress shielding, and instability. Post-operative motion and outcomes were reported at most-recent follow-up. Results. At an average follow-up of 30 months, 7 of the 17 patients (41%) demonstrated radiographic loosening. Six of the 10 patients (60%) without loosening demonstrated stress shielding (average 6mm). Functional outcome scores included a mean ASES of 74, MEPS of 87, VAS Pain of 1, VAS Function of 8 and SANE of 79. Average flexion-extension arc was 13°–138°, and average pronation-supination was 77°–76° (Figure 1). Of the patients with radiographic loosening, 86% had undergone RHA with an associated ligamentous injury of the elbow. Satisfaction among patients was high, as no patient reported an unsatisfactory outcome. Conclusions. The use of an anatomic, press-fit monopolar RHA in the management of acute complex radial head fractures has yielded excellent clinical outcomes despite high rates of radiographic loosening and stress shielding. Press-fit RHA in the setting of ligamentous injury warrants further investigation due to a high rate of implant loosening observed