Efficacy and safety of monopolar versus bipolar radial head arthroplasty: a systematic review and meta-analysis

BACKGROUND

Radial head replacement is the main line of treating complex unstable elbow injuries. Radial head prostheses are either monopolar or bipolar. The difference between both designs in patients' clinical outcomes and postoperative complications is not yet clear. So, a systematic review and meta-analysis was conducted to evaluate the efficacy and safety of monopolar vs. bipolar implants.

MATERIALS AND METHODS

PubMed, EMBASE, Cochrane, and Scopus were searched to identify studies comparing monopolar and bipolar implants. Data on clinical outcomes, postoperative complications, revision, and removal rates were extracted.

RESULTS

Nine studies met our inclusion criteria, with a total of 591 patients (365 monopolar and 226 bipolar). Both prostheses achieved similar ranges of motion; Mayo Elbow Performance Score; Disabilities of the Arm, Shoulder, and Hand score; and visual analog scale for pain. Incidence of postoperative complications was also similar between both designs. Revision and removal rates were 24%, 8% and 29%, 14% for monopolar and bipolar implants, respectively, but no statistically significant difference could be detected.

CONCLUSIONS

No significant difference was found between monopolar and bipolar radial head prostheses in terms of efficacy and safety. Therefore, high-quality randomized controlled trials are required to determine the superiority of one design over the other.

Traumatic Elbow Mediolateral Investigatory Screening: The value of the sitting axial mediolateral projection in the diagnosis of radial head fractures

BACKGROUND

Elbow injuries are frequently encountered in hospital practice, while radial head fractures are the commonest result of such trauma. Diagnosis of radial head fractures is based on clinical and radiographic evaluation with a number of X-ray projections being available. A combination of views is chosen, comprising of routine elbow series screenings and modified techniques, as well as the assistance of the fat-pat sign; never the less fractures can still be occult on X-rays.

PURPOSE

This article aims to demonstrate the diagnostic value of the sitting axial mediolateral projection, which in our hospital is referred to as the Traumatic Elbow Mediolateral Investigatory Screening (TEMIS). This projection has been successfully used in our hospital repeatedly for the identification of occult fractures that were missed by other projections.

MATERIALS AND METHODS

62 patients who presented to our Emergency Department due to trauma in the elbow over a six-month period were X-rayed for the identification of fractures. Projections included an anteroposterior, a lateral and TEMIS.

RESULTS

Radial head fractures (Mason type I) were identified in 14 out of 62 patients. 2 of these were only visible on the TEMIS projection, while they were missed by the other two views.

CONCLUSION

Trauma to the elbow is a common type of injury. Minor fractures can be expected to heal with good results; complications, however, should not be underestimated. Improper healing can result in a permanently malfunctioning joint with restricted movement and stiffness. To avoid such consequences the choice of a reliable screening projection is significant. In our case the diagnostic value of the TEMIS projection lies in the fact that it shows all fractures seen on routine screenings and reveals fractures missed by them, also being well tolerated by patients due to comfortable arm placement during the screening. All in all, when a fracture is suspected on the basis of clinical signs but no radiographic evidence is seen on conventional screenings, the TEMIS view is recommended for further investigation.

A biomechanical study of headless compression screws versus a locking plate in radial head fracture fixation

HYPOTHESIS

Fixation of a 3-part radial head fracture with cannulated compression screws will show equivalent stiffness to a locking plate under axial load. Debate exists regarding the management of Mason type III fractures, with many believing that open reduction and internal fixation provides advantages over other options. By virtue of their subarticular placement, screw fixation is less likely to cause impingement compared with plate fixation, which can result in loss of rotation and requirement for hardware removal. Insufficient fixation stability can lead to nonunions, necrosis of the radial head, pain, and instability. We tested the mechanical stability of fixation of simulated radial head fractures using headless compression screws compared with standard plate construct.

METHODS

Standardized test constructs were created with repeatable osteotomy cuts and hardware placement on each Synbone model (Synbone AG, Malans, Switzerland). We presectioned 22 proximal radius Synbone models to simulate a 3-part radial head fracture. The models were fixed using a radial head locking plate or headless compression screws in a tripod construct. The constructs were potted into a compression test jig using 2-part epoxy resin. Compression testing was performed using a 30-kN Instron Universal machine (Instron, Norwood, MA, USA). The compression tool was spherical, representing the surface of the capitellum.

RESULTS

There was no significant difference between the stiffness of the Synbone constructs under axial load.

CONCLUSION

There was no significant difference between fixation stiffness of a 3-part radial head fracture with headless compression screws in a tripod structure vs. a locking plate in Synbone. Further study is required to allow clinical application.

Prosthesis replacement in Mason III radial head fractures: A meta-analysis

INTRODUCTION

This present study was to evaluate the clinical efficacy of prosthesis replacement (PR) for patients with Mason III radial head fractures (RHF) compared with open reduction and internal fixation (ORIF).

METHODS

We retrieved the relevant trials up to September 2013 from several public databases, mainly including PubMed, Embase, Springer, Elsevier Science Direct, Cochrane Library, Google scholar, CNKI and Wanfang database. Weighted mean difference (WMD) or odds ratio (OR) and their 95% confidence intervals (CI) were calculated to compare the clinical outcomes between PR and ORIF.

RESULTS

A total of 9 studies including 365 patients with Mason III RHF (169 patients treated with PR and 196 patients treated with ORIF) were reanalyzed in the meta-analysis. The results showed that the patients with Mason III RHF receiving PR, compared with the ORIF ones, had a significantly higher percentage of postoperative excellent and good rate (OR=3.48, 95% CI=1.98 to 6.11, P<0.0001), better Broberg and Morrey elbow scores (WMD=9.79, 95% CI=4.22 to 15.36, P=0.0006) and significantly lower postoperative complications (OR=0.33, 95% CI=0.16 to 0.69, P=0.003).

CONCLUSIONS

Although the results of this study supported the use of PR in the treatment of Mason III RHF in Chinese population with short-term outcomes, the evidences are of low quality and further studies were required for confirming these results in the longer term on other populations.

LEVEL OF EVIDENCE

Level III. Low power meta-analysis.