Do we really need to repair the pronator quadratus after distal radius plating?

Purpose:Fractures of distal radius are one of the common orthopaedic injuries.Placing the plate on volar surface requires release of underlying pronator quadratus(PQ)muscle.No consensus is present in the literature about the repair or not of the PQ.The purpose of this study was to evaluate the influence of PQ repair on functional outcome and complications.Methods:Retrospectively 83 patients of distal radius fractures managed with volar plating between 2014 and 2016 were evaluated.Demographic data,operative notes and physical therapy records were retrieved.Patients were divided into group A where PQ repair was done and group B where no repair was done.Functional data such as range of motion(ROM),grip strength,visual analogue scale(VAS)score and disabilities of arm,shoulder and hand(DASH)score at 4 weeks,3 months,6 months and finial follow-up were retrieved.Results:Totally 63 patients(n=29 in group A and n=34 in group B)with the mean age of 51.64 years were examined.Patients were followed up for a mean of 35.2 months(range 27.2-47.1 months)in group A and 38.6 months(range 28.6-51.0 months)in group B.Though functional outcome of the affected limb was not significantly different between two groups after 3 months,PQ repair did affect the recovery at an early stage.Repair group had significantly better ROM(p=0.0383)and VAS score at 4 weeks(p=0.017)while grip strength(p=0.014)was significantly better at 3 months.Conclusions:Repair of PQ may provide pain relief and increased ROM in early postoperative period and hence every attempt should be made to achieve the repair.

Friction and wear behavior of Cu-4 wt.％Ni-TiC composites under dry sliding conditions

The present study synthesized Cu-4 wt％ Ni matrix composites reinforced with different percentages of TiC (0,2,4,6,and 8 wt％) through high-energy ball milling,followed by compaction and sintering.The friction and wear behavior was examined at four different normal loads of 5,10,15,and 20 N.A constant sliding speed of 1.25 m/s was maintained while sliding against a hardened counterface made of EN31 steel (HRC 60) under ambient conditions using a pin-on-disk test rig.The composite hardness increased until the addition of 4 wt％ of TiC,beyond which it was observed to decrease.Such a trend may be attributed to the TiC agglomeration in the composites containing relatively larger amounts of TiC (i.e.,6 and 8 wt％).The wear rate linearly increased with the load.However,the composites exhibited a lower rate of wear than the matrix alloy,which may have resulted from the relatively higher hardness of composites.The observed friction and wear behavior has been explained on the basis of hardness and presence of the transfer layer on the worn surface and its nature,i.e.,loose or well compacted.Addition of 4 wt％ TiC showed the optimum performance in terms of friction and wear caused by its higher hardness and ability to hold a transfer layer of a relatively larger thickness compared to the other materials.The wear mechanism for the Cu4Ni matrix alloy was a mix of adhesive and oxidative wear and primarily abrasive for the composites containing hard TiC particles.