Radial Head Replacement Research Articles

Radial head fractures.

The shape and size of the radial head is highly variable but correlates to the contralateral side. The radial head is a secondary stabilizer to valgus stress and provides lateral stability. The modified Mason-Hotchkiss classification is the most commonly used and describes three types, depending on the number of fragments and their displacement. Type 1 fractures are typically treated conservatively. Surgical reduction and fixation are recommended for type 2 fractures, if there is a mechanical block to motion. This can be done arthroscopically or open. Controversy exists for two-part fractures with >2 mm and <5 mm displacement, without a mechanical bloc as good results have been published with conservative treatment. Type 3 fractures are often treated with radial head replacement. Although radial head resection is also an option as long-term results have been shown to be favourable. Radial head arthroplasty is recommended in type 3 fractures with ligamentous injury or proximal ulna fractures. Failure of primary radial head replacement may be due to several factors. Identification of the cause of failure is essential. Failed radial head arthroplasty can be treated by implant removal alone, interposition arthroplasty, revision radial head replacement either as a single stage or two-stage procedure.

Correlation between radiographic findings and clinical failure in monopolar radial head replacement.

The purpose of this study is to analyze the mid-term outcomes of a modular monopolar type of radial head arthroplasty in the treatment of complex fractures associated with acute elbow joint instability. We postulated that radiographic changes are related to the development of clinical complications. We evaluated at last follow-up 26 radial head arthroplasties in 26 consecutive patients who were followed for at least one and a half year. All patients had suffered radial head fractures (Mason III) in the context of unstable elbow injuries. Definitive treatment of the radial fracture was performed with modular and monopolar prosthesis which was inserted as a press fit. All patients were evaluated preoperatively and postoperatively. The evaluation included a clinical examination and a protocolized imaging study (standard X-Rays and CT) of the elbow. We analyzed the incidence of: heterotopic ossifications, secondary radiocapitellar joint osteoarthritis, hardware loosening, hardware disengagement, and joint infection. Diagnosis of clinical failure of the implant was defined as the time to the second surgery due to major complications related to the prosthesis, such as persistent lateral side pain or elbow stiffness and any kind of implant instability or dislocation. Theimplant-specific reoperation rate was 15% (four reoperations). The need for the second surgery was statistically associated with heterotopic ossifications, radiocapitellar osteoarthritis and cortical resorption around radial neck (p = 0.054, p = 0.033, and p = 0.019, respectively), being periprosthetic osteolysis the most likely factor related to failure, and radial pain the main symptom leading to surgical revision. Our study shows a positive association between radiographic findings and patient symptoms for postoperative complications after radial head arthroplasty. Failed radial head replacements may lead to reoperation mainly due to pain, and this can be distinguished from other causes of pain in elbow region based on its radial location. Radiological loosening was prevalent in this group of failed replacement.

High Risk of Further Surgery After Radial Head Replacement for Unstable Fractures: Longer-term Outcomes at a Minimum Follow-up of 8 Years.

The evidence for treating acute, unreconstructable radial head fractures in unstable elbows with radial head replacement predominantly consists of short- to mid-term follow-up studies with a heterogenous mix of implants and operative techniques. Data on longer-term patient-reported outcomes after radial head replacement is lacking. (1) What proportion of patients undergo revision or implant removal after radial head replacement? (2) At a minimum of 8 years follow-up, what are the patient-reported outcomes (QuickDASH, Oxford Elbow Score, and EuroQol-5D)? (3) What factors are associated with a superior long-term patient-reported outcome, according to the QuickDASH? Between September 1994 and September 2010, we surgically treated 157 patients for acute radial head fractures. We excluded patients where the radial head was excised (n = 21), internally fixed (n = 15), or replaced as a secondary procedure after failed internal fixation (n = 2). A total of 119 patients who underwent radial head replacement surgery for an acute unreconstructable fracture were included, with a mean age of 50 years (range 15 to 93 ± 19 years), and 53% of patients (63) were women. All but two implants were uncemented, loose-fitting, monopolar prostheses, of which 86% (102) were metallic and 14% (17) were silastic. Implants were only cemented if they appeared unstable within the proximal radius. Silastic implants were used in the earlier series and replaced by metallic implants starting in 2000. We reviewed electronic records to document postoperative complications and prosthesis revision and removal. A member of the local research team (THC, CDC) who was not previously involved in patient care contacted patients to confirm complications, reoperations and to obtain long-term patient-reported outcomes scores. Nineteen patients had died at the point of outcome score collection. Of the remaining 100 patients, 80 were contacted (67% of total cohort), at a median of 11 years (range 8 to 24 years) after injury. The primary outcome measure was the QuickDASH score. Of 119 patients, 25% (30) underwent reoperation, with three patients undergoing revision and 27 patients undergoing prosthesis removal at a median of 7 months (range 0 to 125 months). Twenty-one of 30 procedures (70%) occurred within 1 year after implantation. Kaplan-Meier survivorship analysis demonstrated a cumulative implant survival rate of 71%. In the 80 patients contacted, the mean QuickDASH score was 13 ± 14, the mean Oxford Elbow Score was 43 ± 6, and the median EuroQol-5D score was 0.8 (-0.3 to 1.0). After controlling for covariates, we found that prothesis revision or removal (p = 0.466) and prosthesis type (p = 0.553) were not associated with patient-reported outcome, according to the QuickDASH. The management of acute unreconstructable fractures of the radial head in unstable elbow injuries with radial head replacement has a high risk of reoperation. Patients must be counselled regarding this risk of secondary intervention, of which the peak risk appears to be within 1 year after implantation. Despite this, patients report low disability according to the QuickDASH at a minimum follow-up of 8 years. Level IV, therapeutic study.

CORR Insights®: High Risk of Further Surgery After Radial Head Replacement for Unstable Fractures: Longer-term Outcomes at a Minimum Follow-up of 8 Years.

CORR Insights®: High Risk of Further Surgery After Radial Head Replacement for Unstable Fractures: Longer-term Outcomes at a Minimum Follow-up of 8 Years.

Posterolateral instability of elbow following radial head excision: A retrospective cross sectional study

Purpose: To study the occurrence of posterolateral instability of elbow joint following radial head excision in patients with radial head fracture and to determine the coexisting condition which contributes to instability.Methods: A retrospective cross sectional study designed to assess the occurrence of posterolateral instability of elbow following radial head excision. 30 patients who had undergone radial head excision for Masons type 2, 3, and 4 fracture between March 2010 to July 2018 were included in the study. On their follow up visit persistent symptom of elbow pain, signs of elbow instability (pivot shift test and chair push up test), mayo elbow score and radiological features were assessed for diagnosing the posterolateral instability of the elbow.Results: Of the 30 patients evaluated 2 of them had associated ulnar fracture and 1 had elbow dislocation. All 3 complained of pain and discomfort at the elbow joint. Pivot Lateral shift test and chair push up test were positive in these 3 cases, with an average Mayo elbow score of 70 in these 3 patients. The average arc of motion among these 3 patients ranged from 5° to 120° with pronation being 88° and supination of 86° as compared to the ones without instability. Two of the three patients showed radiological features of instability.Conclusion: Most radial head fractures treated with radial head excision have good outcome clinically, provided it is not associated with any concomitant injury of the elbow and if immobilized properly for minimum of 3 weeks post-surgery to allow for soft tissue healing. A small proportion of patients who have concomitant elbow dislocation or ulna fracture with persistent elbow pain, should undergo further clinical and radiological evaluation in the form of MRI and decision should be taken regarding need for ligament reconstruction or radial head replacement. Hence c existence of elbow dislocation or proximal ulna fracture should be a red flag sign for increased chances of posterolateral instability of the elbow.

Low return-to-sports rate after elbow injury and treatment with radial head arthroplasty

The aim of this study was to analyze sports participation after radial head arthroplasty among recreational athletes. A total of 57 recreational athletes (mean age, 49 years; age range, 18-79 years) treated with radial head arthroplasty for non-reconstructible radial head fractures were included in this retrospective study. The return-to-sports rate and the time to return to sports were analyzed. The clinical and radiologicoutcomes were compared between patients who returned to sports (group 1) and those who did not (group 2). After a mean follow-up period of 8.4 years (range, 2.5-16.4 years), 30 of 57 patients (53%) had returned to sports. The mean sports frequency significantly decreased from 5.2 ± 5.0 h/week to 2.2 ± 2.9 h/week after surgery (P < .001). In group 1, 83% of patients returned to the same sports activity whereas 17% changed to a less demanding sports activity. The mean time to return to sports was 158 days (range, 21-588 days). Patients who returned to sports had a significantly better Mayo Elbow Performance Score (MEPS) (84 ± 19 points vs. 63 ± 20 points, P < .001); Disabilities of the Arm, Shoulder and Hand score (16 ± 17 vs. 46 ± 22, P < .001); and arc of flexion (114° ± 32° vs. 89° ± 36°, P = .007). A secondary radial head prosthesis (P = .046) and MEPS lower than 85 points (P = .001) were associated with a significantly lower return-to-sports rate. No differences regarding radiographic changes were found between the 2 groups (P ≥ .256). The return-to-sports rate after radial head replacement is low. A secondary radial head prosthesis and a worse clinical outcome (MEPS < 85 points) significantly increase the risk of not returning to sports after radial head arthroplasty.

Fragment volume and surgical methods in radial head fracture

Objective To investigate the relationship between volume of fracture fragment and surgical methods in patients with radial head fracture. Methods A retrospective study was conducted of the 60 patients with radial head fracture of Mason type Ⅲ who had been admitted to the Department of Hand Surgery, Wuhan Pu＇ai Hospital from January 2013 to December 2016. They were 28 males and 32 females, aged from 26 to 71 years (average, 54.5 years). Of them, 41 underwent open reduction and internal fixation (incision group) and 19 radial head replacement (replacement group). The volumes of radial head and fracture fragment were measured by CT scan and three-dimensional reconstruction of the elbow joint before operation. A volume-weighted ratio R corresponding to a specific radial head fragment was calculated. Correlation between the volume-weighted ratio R of the radial head fragment and the Broberg-Morrey elbow function score was calculated. At the last follow-up, the Broberg-Morrey elbow function score was used to assess the efficacy and complications were recorded in the 2 groups. Results All the 60 patients were followed up for 20 to 36 months (mean, 28.6 months). At the last follow-up, the Broberg-Morrey elbow function score was 86.5±1.3 points (from 72 to 91 points) for the incision group and 93.6±1.4 points (from 78 to 95 points) for the replacement group; the complication rate was 17.1% (7/41) for the former and 15.8% (3/19) for the latter. There was a linear relationship between the volume-weighted ratio R of the radial head fragment and the Broberg-Morrey elbow function score in the incision group. The linear regression equation between the two was: y=65.63+0.67x (R2=0.85, P=0.0006). There was no linear relationship between the volume-weighted ratio R of the radial head fragment and the Broberg-Morrey elbow function score in the replacement group (P=0.053). When the Broberg-Morrey elbow joint function score (93.6 points) for the replacement group was substituted into the linear regression equation y=65.63+0.67x (y=93.6), x=41.7. Conclusions In the patients with radial head fracture of Mason type Ⅲ, open reduction and internal fixation may lead to a better prognosis for those with a volume ratio ≥41.7 between the radial head and fracture fragment while radial head replacement may lead to a better prognosis for those with a volume ratio < 41.7 between the radial head and fracture fragment and for those elderly ones with osteoporosis. Key words: Elbow joint; Arthroplasty, replacement; Bone plates; Relationship; Radial head fracture

Functional Outcome of Elbow Kinematics in Radial Head Excision Versus Radial Head Replacement: A Comparative Study.

BACKGROUND:Radial head fractures are quite common with incidence 1.5-4% of all adult fractures. The treatment for these fractures depends upon age, type of injury and whether the physics is closed or not.AIM:Comparison between radial head excision versus radial head replacement based on mayo elbow scoring in comminuted radial head fractures.MATERIAL AND METHODS:We did a prospective comparative study comprising 32 patients between age 22-60 years with Mason type II/III radial head fractures at Sir J.J Group of Hospitals, Mumbai. The patients were randomised using the admission day of the week placing 17 patients in the arthroplasty group and 15 patients in the excision group. The patients were followed up for 18-24 months (average 20 months) postoperatively. Results were analysed by the Mayo’s elbow performance score at 6 months and 18 months and were statistically evaluated by unpaired t-test.RESULTS:At 6 months, radial head arthroplasty gave excellent results in 2 patients, good in 5 patients and fair in 8 patients. In excision, there were 5 patients with excellent results at 6 months, 7 with good results and 2 with fair results. At 18 months, of the 17 patients who had undergone head arthroplasty, 2 had excellent results, and the same number had poor results. 7 (46.7%) of the 15 cases who had undergone radial head excision had excellent results. Good results were obtained in 7 cases of each. There was 6 cases (35.3%) of radial head arthroplasty which fell into the fair group. As per Mayo’s score at 6 months follow up, mean and standard deviation (SD) of the scores in arthroplasty was 68.82 and 18.66 respectively & for excision, it was 85.66 and 10.66. At 18 months follow up, it was 75 and 14.89 for arthroplasty & 90.66 and 7.98 for excision. The difference between the results was statistically significant (p < 0.01).CONCLUSION:Our study shows that long and short-term results of radial head excision are better as compared to arthroplasty in comminuted radial head fractures based on mayo elbow scoring, particularly for dominant upper limbs.

Elbow Arthroplasty: From Normal to Failure

Total elbow arthroplasty is currently an established surgical treatment for several pathologies of the elbow. Although initially used primarily in the treatment of rheumatoid arthritis, indications for total elbow arthroplasty have expanded and now include trauma, primary and secondary osteoarthritis, fracture nonunion, and following neoplasm resection. Desired outcomes of elbow arthroplasty include decreasing patient pain, restoration of function and mobility, and prevention of or treatment for instability. In comparison with total elbow arthroplasty, radial head replacements are most commonly performed following trauma. An additional technique, capitellar resurfacing arthroplasty, was developed in an effort to prevent early-onset osteoarthritis secondary to altered elbow biomechanics following radial head replacement. Complications of these surgeries include loosening, fracture, instability and dissociation, bushing wear, and particle disease.

Long-term Outcomes after Primary Radial Head Resection Arthroplasty vs. Acute Radial Head Resection vs. Secondary Prosthetic Removal in Comminuted Radial Head Fractures.

Aim of this study was to compare the clinical and radiological long-term outcomes following operative treatment of comminuted radial head fractures using 1) primary radial head resection arthroplasty, 2) acute radial head resection, or 3) necessary secondary prosthetic removal. Additionally, we evaluated complex radial head fractures combined with elbow dislocation and verified the hypothesis of whether primary radial head resection arthroplasty could contribute to ligament healing. In a comparative retrospective cohort study between 2004 and 2014, 87 (33 female, 54 male) patients with comminuted radial head fractures with a median age of 45 (range 18-77) years were included and followed-up clinically and radiologically. Functional results were evaluated according to MEPS, DASH, Broberg and Morrey, and VAS scores. After a median range of 46 months postoperatively, 48 patients (group 1) obtained an acute radial head resection arthroplasty (MEPS: 70 points, Broberg and Morrey: 63 points, DASH: 34 points, VAS: 3.3 points). Twenty patients (group 2) were treated by radial head resection (MEPS: 63 points, Broberg and Morrey: 50 points, DASH: 49 points, VAS 4.2 points) and 19 patients (group 3) needed secondary prosthesis removal (MEPS: 73 points, Broberg and Morrey: 66 points, DASH: 38 points, VAS: 2.8 points). The overall outcome demonstrated a trend towards better results and the Kellgren-Lawrence grade of postoperative osteoarthritis was significantly better in groups 1 and 3 compared to group 2 (P=0.02). Clinical and radiological long-term results of this study demonstrate a trend towards a better outcome after acute radial head resection arthroplasty compared to primary radial head resection, especially in complex fractures associated with elbow dislocation. Furthermore, our results encourage the use of primary radial head replacement in cases of comminuted non-reconstructable radial head fractures.

Replacement or repair of terrible triad of the elbow: A systematic review and meta-analysis.

Background:Surgical treatment for terrible triad injuries remains a challenging clinical problem, and controversy exists of whether it is better to repair or replace the radial head. The objective of this systematic review was to evaluate the clinical outcomes of repair and arthroplasty replacement of the radial head in patients with terrible triad injury.Methods:Medline, Cochrane Library, EMBASE, and Google Scholar were searched up to July 30, 2018 to identify the relevant studies, which included patients who had received treatments of the terrible triad of the elbow and also had reported with the quantitative outcomes. Outcomes of interest were functional outcomes.Results:Four studies with a total of 115 patients were included in the systematic review. Most patients were type II or III radial head fractures based on the Mason classification systems. Fifty-one patients received radial head repair surgery and 64 underwent replacement. Two studies had indicated that patients in the replacement group were significantly associated with better treatment outcome assessed by DASH (Disabilities of the Arm, Shoulder and Hand) and MEPS (Mayo Elbow Performance Score) scores. The meta-analysis indicated that patients with the arthroplasty replacement were associated with significantly better ROM outcomes in flexion, extension, pronation than those with radial head repaired. In addition, patients in the replacement group showed fewer post-surgery complications than those in the repair group.Conclusions:Our review had indicated that patients with terrible triad injuries undergo arthroplasty replacement have better clinical outcomes and fewer post-surgery complications than those received the repair surgery. Radial head replacement might be a more effective treatment approach with good clinical outcomes for patients with a terrible triad of the elbow.

Radial head replacement versus reconstruction for the treatment of the terrible triad injury of the elbow: a systematic review and meta-analysis

IntroductionThe terrible triad injury of the elbow (TTIE) remains challenging to manage and has been associated with high complication rates and poor outcomes. There is a trend towards performing radial head replacement (REP) in preference to radial head reconstruction (REC) as arthroplasty provides early stability and may allow mobilisation sooner, potentially resulting in a better functional outcome. This systematic review compares the outcome of patients with TTIE treated with either REC or REP.Materials and methodsMEDLINE, Embase, and CINAHL were searched for studies published in English involving at least ten patients exclusively with a TTIE managed operatively, including both patients with either REC or REP. Data collection was in accordance with the Preferred Reporting Items for Systematic Review and Meta-analysis protocol. The outcomes of interest were Mayo Elbow Performance Score (MEPS) and range of motion (ROM). Post-operative complications were also compared.Results9 studies involving 210 patients were included (98 REPs and 112 RECs). There was no statistically significant difference (p = 0.51) demonstrated between in the mean MEPS of the REP group (mean 88.6) and REC group (mean 88.5). Similarly, there was no statistically significant difference demonstrated between the REP and REC groups in terms of ROM. The risk of re-operation was high in both the REP (18.4%) and REC (17.9%) group. The overall complication rate of all patients included in the study was high (65%).ConclusionsComparable results with good outcomes in terms of functional scores and ROM can be achieved with both REP and REC when treating TTIE, although the re-operation rate for both remains relatively high. Given there is no apparent clear advantage between the two treatment groups, we would suggest that REC should be performed when a satisfactory fixation can be achieved as the longevity of REP in young patients with a TTIE is currently uncertain.

Reverse vascularized bone graft of the lateral distal humerus for non-union of the radial neck fracture: anatomical study and case report

A few treatment options for radial neck non-union have been reported, including radial head excision, radial head replacement, and internal fixation with a bone graft. We describe a new treatment for radial neck non-union using a reverse vascularized bone graft of the lateral distal humerus. In the anatomical study, the posterior radial collateral artery (PRCA) was dissected in eight fresh-frozen cadaver arms. The number of branches from the PRCA to the humerus was determined, and the distances from these branches to the lateral epicondyle of the humerus were measured. We then used this information to create a reverse vascularizedhumeral bone graft, which was used to treat non-union of a radial neck fracture in a 73-year-old female. There were two to four PRCA branches (mean: 3.3) entering the bone. The distance from the branches to the lateral epicondyle of the humerus ranged from 2.5 to 10.8 cm. The mean distances from the most proximal and distal PRCA branches to the lateral epicondyle of the humerus were 7.6 cm and 3.4 cm, respectively. The case of non-union of a radial neck fracture was successfully treated with a reverse vascularized humeral bone graft. There were no major complications, and radiographs showed bony union at 8 weeks postoperatively. This procedure may become a new option for the treatment of non-union of fractures of the radial head and neck, as it enables preservation of the radial head, which is an important structure in the elbow and proximal radioulnar joints.

Matching precision of the reverse contralateral radial head in generating of the individualized prosthesis from the surface registration in tuberosity-neck and in tuberosity-diaphysis.

Following the radial head replacement, the surface mismatches between the implants and the morphological characteristics of the original proximal radius decreased contact areas and increased contact forces which is potential for the long-term articulating cartilage wear. Several studies demonstrated that the individualized prosthesis, created from computed tomographic (CT) images of the contralateral side with the reverse engineering technology, may reduce the mismatch. The aim of this study is to demonstrate the matching precision of the reverse contralateral head between the surface registration in tuberosity-neck (TN) area and in tuberosity-diaphysis (TD) area. High-resolution CT scan of 11 pairs of the cadaveric arms was performed. Utilizing advanced image processing techniques, three-dimensional (3-D) models of each specimen was generated. The model of the left side was reversed and matched with the model of the right side in the same cadaver by registering in the area of radial neck along with tuberosity (TN) and in the area of radial tuberosity combined with 2 cm of proximal diaphysis (TD). The alteration of the head diameter, dish diameter, articular depth, head thickness, end-plane angle, offset, and head volume were evaluated and analyzed by paired t-test. No statistically significant difference was found in all parameters from both TN and TD registrations ( p < 0.05). The surface registration in either TN or TD area can generate the statistically symmetrical 3-D model with the original head. The registration in these areas may possibly be used in creating the individualized radial head prosthesis.

Prospective comparative study of short term functional outcomes of radial head excision arthroplasty and radial head replacement arthroplasty in radial head fracture

The radial head is essential for the rotational stability of the forearm and resistance to valgus stress. Radial head fractures are the most common elbow fracture in adults, constituting approximately one third of all elbow fracture. Primary goal in surgical treatment is to restore elbow stability in order to preserve the complex physiologic elbow kinematics. Our study is to compare functional outcome between excision arthroplasty and replacement arthroplasty and we found no difference between functional outcomes in short term between the two modalities of treatment.

Surgical treatment of radial head fractures with elbow dislocation

Objective To explore the clinical efficacy of surgical treatment for radial head fractures with elbow dislocation. Methods From October 2013 to October 2016, 22 cases of Mason-Johnston typeIVradial head fractures were performed surgical treatment. There were 14 cases of Mason typeIIfracture and 8 cases of typeIIIfracture. The patients were followed up clinically and radiographically until the fracture healing and elbow function entering the plateau stage. The Mayo Elbow Performance Score (MEPS) was used for the functional assessment. Results Nineteen cases of radial head fractures underwent internal fixation, and 3 cases underwent radial head replacement. The postoperative follow-up period ranged from 13 to 36 months with an average of 20 months. The elbow flexion and extension arc averaged (106±17)°, and the forearm rotation arc averaged (140±18)°. The X-ray films of all the patients showed that the concentric reduction of the elbow was maintained. No instability of the joint was found, and the reduction and fixation of the radial head fracture were satisfactory. The healing time of radial head fracture was 11 to 17 weeks with an average of 12. 5 weeks. No complications such as prosthesis dislocation were found after operation in the 3 cases of prosthetic replacement. At the last follow-up, MEPS was 60 to 100 points with an average of (91±7) points. The function was rated as excellent in 8 cases, good in 13 cases and poor in 1 case. There were 5 cases of elbow heterotopic ossification, 4 cases without further surgical treatment. And 1 case underwent surgical release. Conclusion Open reduction and internal fixation or radial head replacement combined with collateral ligament repair for the treatment of radial head fractures with elbow dislocation can obtain satisfactory clinical efficacy. Key words: Fractures, bone; Treatment outcome; Radial head; Elbow dislocation

Timely recognition of total elbow and radial head arthroplasty adverse events: an analysis of reports to the US Food and Drug Administration

Recent recalls of several commonly used elbow arthroplasty implants have prompted interest in the modes by which elbow implants fail and the timing of reports of these failures. We reviewed the adverse event reports to the US Food and Drug Administration's Manufacturer and User Facility Device Experience (MAUDE) database from 2012 to 2015 regarding elbow arthroplasty to determine the event date and the type of each adverse event. Among 179 total elbow adverse event reports, the most common modes of failure were implant dissociation (23%), loosening (22%), and infection (16%). The most common modes of failure among 58 radial head replacement reports were component dissociation (19%) and linkage screw failure (19%). The percentage distribution of adverse event types differed among different arthroplasty systems and from that reported in published reviews of elbow arthroplasty. Three implant recalls were implemented 2, 5, and 9 years after the first adverse event report in the MAUDE database. For 2 of the recalls, the first reports of the device failures were published 2 and 5 years after the first MAUDE reports. The MAUDE database is a publicly funded and publicly available means by which surgeons can identify adverse events for the prostheses they use before such information becomes available through journal publication or recall notification. In this study, MAUDE data revealed a higher relative frequency of mechanical dissociation of elbow implants than what has been represented in the literature. Early identification of these adverse events may help surgeons by informing their implant selection and surgical technique.

Diagnosis and treatment of bipolar fracture-dislocation of the forearm

Objective To investigate diagnosis and surgical treatment of bipolar fracture-dislocation of the forearm. Methods A retrospective study was conducted of 16 patients with forearm bipolar fracture-dislocation who had been treated and completely followed up at Department of Orthopaedic Trauma, Beijing Jishuitan Hospital from March 2011 to September 2017. They were 14 males and 2 females, aged from 17 to 48 years (average, 35.8 years). Their injury involved 7 left and 9 right sides, and 10 dominant and 6 non-dominant sides as well. Their proximal injury was divergent elbow dislocation in 4 cases, convergent elbow dislocation in one case, Monteggia fracture-dislocation in 9 cases (2 ones of type I, 2 ones of type ⅡB, 4 ones of type ⅡC and one of type Ⅳ), and upper radioulnar dislocation in 2 cases. Their distal injury was distal radial fracture (intra-articular)+lower radioulnar dislocation in 7 cases, distal radioulnar fracture+lower radioulnar dislocation in 2 cases, Galeazzi fracture (1/3 distal humeral shaft) in 3 cases, and middle and upper middle radial fracture+lower radioulnar dislocation in 4 cases. Open reduction and internal fixation was performed for all the shaft fractures and most of the distal radial fractures. One distal radius fracture was treated with closed reduction and external fixation, one case with external fixation, one case with needle insertion and external fixation, 3 radial head fractures with internal fixation, 3 cases with radial head replacement, 2 cases untreated, 5 cases with open ligament repair because their primary closed reduction failed, and 2 cases with hinged external fixation of the elbow. Their functional exercise started according to judgment of joint stability after surgery. At the last follow-up, the overall function of the forearm was evaluated according to the Anderson＇s scoring. Results The 16 patients were followed up for an average of 26.0 months (from 6 to 60 months). All fractures healed at the internal fixation sites after operation with no abnormality affecting the function. No infection occurred. All the elbow joints and upper and lower radioulnar joints were stable. All the radial head replacements were in good position. The range of elbow flexion and extension averaged 123.2° (from 60° to 140°), the range of wrist flexion and extension 150.3° (from 120° to 160°), and the rotational mobility of the forearm 144.4° (from 70° to 170°). At the last follow-up, according to the Anderson's scores, 11 cases were rated as excellent, 3 cases as satisfactory, one case as unsatisfactory and one case as failure. Conclusions Most of the forearm bipolar fractures and dislocations are high-energy injury. The key to treatment is to achieve good reduction of distal and proximal dislocations and to start rehabilitative exercise as early as possible. Intraoperative fixation of fractures should be based on stable reduction of the dislocation. Fine reduction of bipolar dislocations and early rehabilitation can lead to good functional recovery. Key words: Forearm injuries; Dislocations; Fractures, bone; Diagnosis; High energy injury

Joint Contact Changes With Undersized Prosthetic Radial Heads.

To evaluate the effect of intentional undersizing of prosthetic radial head implant diameters on joint contact pressures. Eight fresh-frozen cadaveric elbows were aligned in neutral extension and loaded with 100 N using a custom testing apparatus. Radiocapitellar contact pressures were recorded using a Tekscan thin-film pressure sensor. Prosthetic radial head replacement was performed with 2 prostheses: the Anatomic Radial Head and the Evolve Proline Radial Head prostheses. Each design was sized according to the manufacturer's recommendations and then again using 2-mm smaller radial heads. Average and peak pressures were significantly higher with the Evolve than the Anatomic prostheses (P < 0.03 and 0.02, respectively). Peak pressures decreased from 4.2 ± 0.5 MPa to 2.9 ± 0.3 MPa for the Anatomic Radial Heads and from 5.6 ± 0.5 MPa to 3.9 ± 0.6 MPa when the Evolve Radial Heads were undersized by 2 mm. The mean pressures of the Anatomic Radial Heads (1.4 ± 0.1 MPa) did not change significantly with undersizing (1.3 ± 0.1 MPa, P = 0.12), whereas the mean pressures of the Evolve Radial Heads (1.6 ± 0.1 MPa) were significantly reduced with undersizing (1.4 ± 0.1 MPa, P < 0.02). Both mean and peak pressures were initially high for the Evolve Radial Head sized based on the short axis diameter and were improved with further undersizing by 2 mm. Peak, but not mean, contact pressures were improved by undersizing the Anatomic prosthesis based on the long axis diameter. These findings support the clinical recommendation of some surgeons to undersize the Evolve prosthesis by 2-mm smaller diameter than the current manufacturer's suggestion and give reason to consider doing the same for the Anatomic prosthesis.

The effect of radial head prosthesis diameter on posterolateral rotatory instability of the elbow

BackgroundThe purpose of this study is to investigate how different diameters of radial head replacement affect posterolateral translation with a valgus and supination force. We hypothesized that there would be less posterolateral rotatory translation with larger implant diameter. MethodsEleven cadaveric arms were stressed at 30 and 60° of flexion with a consistent supination and valgus stress force under five conditions: native radial head, radial head excision, and with 3 sizes of radial head prosthesis. Displacement of the radial head posteriorly in relation to the capitellum on radiographs was measured. Displacement was expressed as a percentage relative to the average of the maximum and minimum native radial head diameters. FindingsThe native radial heads had average minimum and maximum diameters of 23.3 mm and 25.2 mm, respectively. The angle of testing did not significantly change translation of the radial head. There was increased posterior translation relative to native head as the radial head sizes decreased from 24 mm to 20 mm and with excision of the radial head. Compared to the native head, the differences in displacement were statistically significant for the 20 mm radial head, but not for the 22 mm or 24 mm replacements. Radial head translation significantly increased after radial head excision. InterpretationsThis cadaveric study illustrates that patients treated with radial head excision and radial head prosthesis with undersized diameters have increased posterior translation with a valgus and supination stress. The larger the radial head prosthesis (closer to native radial head), the more closely it approximated the amount of translation of the native radial head.