ABSTRACT
Objective To evaluate correlation of radial head fracture with forearm interosseous membrane (IOM) injury.Methods Twenty-six patients with radial head fractures were studied prospectively between September 2007 and June 2010.There were 15 men and 11 women,with an average age of 37.6years (range,21-53).According to the Mason classification,there were 7 cases of type Ⅰ,9 cases of type Ⅱ,10 cases of type ⅢL All patients were subjected to forearm X-ray,CT scans and the MR within a week.Clinical and radiographic data of all the patients were collected.Spearman rank correlation statistical analysis was used to analyze the correlation between the radial head fracture and the IOM injury.Results The radial head fractures and IOM injury were directly related.The IOM injury was noted in all type of radial head fracture.The more severity radial head fracture had,the more IOM injury happened.In Mason Ⅰ-Ⅲ fractures,IOM injury was found in 2,4 and 7 cases respectively.The different degree of radial head fracture caused different effects on IOM injury.The severity of radial head fracture was correlated with damage degree of IOM.In Mason type Ⅰ and type Ⅱ fractures,the IOM injury were just partial disruption with distal part of the IOM and did not reach the biomechanically essential central band.In type Ⅲ fractures,central band disruption was found in 3 cases.Conclusion Mason Ⅰ-Ⅲ radial head fractures are associated with forearm IOM injury.There was a positive correlation between radial head fractures and IOM injury.If IOM lesions are suspected,magnetic resonance imaging should be performed,especially Mason Ⅲ fractures.
ABSTRACT
Objective To evaluate the effect of pronator teres tendon reconstructing the forearm interosseous membrane(IOM)central band on restoring the longitudinal stability of the forearm after Essex-Lopresti injury.Methods A total of ten fresh-frozen adult cadaveric forearms were loaded axially through the humeral and the distal radius.Each forearm was tested as following six steps:radial head excision,radial head plus excision of triangular fibrocartilage complex(TFCC),radial head plus TFCC plus excision of IOM central band,reconstructing central band with pronator teres tendon,metallic radial head prosthesis replacement,central band reconstruction plus radial head prosthesis replacement.The difference of the load exerted to displace the radius to the proximal for 5 mm was compared at different steps by using single-factor analysis of variance.Then,the effect of each step on restoring the forearm longitudinal stability of the forearmwas evaluated.Results There was statistical difference upon load for the radial displacement to the proximal for 5 mm in all six steps,ie,(74.51±15.17)N,(49.23±6.14)N,(17.83±4.73)N,(27.40±3.56)N,(140.25±25.39)Nand(164.21±28.26)N,respectively(P＜0.01).With migration of the radius to proximal for 5 mm,the load for pronator teres reconstruction was 55.66% of radial head plus TFCC,and the load for pronator teres reconstruction plus radial head prosthesis replacement was 559.31% of IOM reconstruction step and 333.56% of radial head excision.Conclusions Reconstruction of the central band with pronator teres tendon is insufficient to restore the longitudinal stability of the forearm after Essex-Lopresti injury.Reconstruction of the central band in combination with metallic radial head prosthesis replacement are beneficial to restoring the longitudinal stability of the forearm.