proximal row carpectomy ( prc ) is a well - established technique for the management of wrist arthritis . poorer long - term outcomes are likely to result in patients engaged in heavy manual labor , whereas better outcomes may be obtained in patients undergoing prc for trauma or earlier - stage kienbck disease . further , singh et al . reported that in the patients with scaphoid nonunion advanced collapse and scapholunate advanced collapse wrist , prc provides better range of motion of the wrist and activities of daily living than before surgery . therefore , prc has become a popular surgical procedure for kienbck disease , especially for stage iiia or iiib of lichtman s classification [ 36 ] . distal radius fracture ( drf ) after this procedure has not been reported in the english literature . here the patient was a 73-year - old female who visited the outpatient emergency clinic of our hospital for chief complaints of pain and deformity of the right wrist joint caused by a fall . the range of motion of the wrist joint before injury was 40 on flexion , 30 on dorsiflexion , 90 on pronation , and 90 on supination , and she had no inconvenience in daily living activities ( referring to the medical records of the previous hospital ) . drf ( ao classification ; type a2 ) accompanied by volar displacement was noted on plain radiography ( fig . 1a and b ) . since the fracture was volar displacement and the dominant hand was affected , surgical treatment was performed aiming at the early recovery of movement for daily living activities . the radius was exposed through henry s approach , and osteosynthesis was performed using a volar locking plate ( acu - loc 2 , japan medical next , osaka , japan ) ( fig . 2a and b ) . no immobilization was applied after surgery , and movement of the fingers and wrist joint was permitted as early as possible . at 6 months after surgery , the range of motion of the wrist joint was 35 on flexion , 60 on dorsiflexion , 90 on pronation , and 90 on supination ; visual analog scale , 2/10 ; quick disabilities of the arm shoulder , and hand score , 27.27/100 ; and modified mayo score , 84 ( excellent ) . no volar locking plate - associated complication developed , and daily living activities recovered to the pre - injury condition . the patient was informed that data concerning the case would be submitted for publication , and she consented . caused drf by positioning the wrist joint at 70 on dorsiflexion and 10 on radial deviation in cadavers . colles fracture occurred in all cadavers , and the grade of crushing was closely associated with the bone mineral density . investigated the developmental mechanism of drf using a 3-dimensional bone model based on an experiment reported by lill et al . . the positions of the lunate and scaphoid with maximum contact areas with the radial joint surface change with movement of the wrist joint . they shift to the volar joint surface on volar flexion and dorsal joint surface on dorsiflexion . thus , stress was concentrated on the dorsal cortical bone and caused dorsal fracture in the 70 dorsiflexion wrist joint model , and volar fracture occurred in the 70 volar flexion model . based on these studies , generally , dorsiflexion of the wrist joint is necessary to cause colles fracture , and flexion of the wrist joint is necessary for causing smith s fracture . in the normal wrist joint , the radiocarpal joint has the largest range of motion on wrist joint flexion , and the angle is about 50. the flexion angle of the midcarpal joint is about 35. on wrist joint dorsiflexion , the angles of the radiocarpal and midcarpal joints are about 35 and 50 , respectively . the region between the lunate and capitate has the greatest range of motion through the midcarpal joint . about 90 flexion and about 70 dorsiflexion of the wrist joint are acquired through the total range of motion of these 2 joints in the normal wrist joint . after prc , the radiocarpal joint is formed by the capitate and lunate fossa of the radius . blankenhorm et al . investigated carpal movement after prc using cadavers , in which the range of motion of the midcarpal joint was larger than that of the radiocarpal joint on flexion and dorsiflexion of the wrist joint . the range of motion of the wrist joint is the total range of motion of the radiocarpal and midcarpal joints in the normal wrist joint , but it decreases after prc , and the flexion angle of the wrist joint decreases to about 50. ulnar deviation is retained , but the range of radial deviation is limited because the triquetrum hits the styloid process of the radius . because of these , the range of motion of the wrist joint is limited after prc . although the wrist joint position at the time of injury was unclear , extracapsular volar displacement fracture was caused , suggesting that the injury was due to wrist joint dorsiflexion or flexion . , 70 wrist joint dorsiflexion or flexion is necessary to cause drf , but this may be difficult for the wrist joint after prc . after prc , the radiocarpal joint is formed by the capitate and lunate fossa of the radius , and the capitate fits into the lunate fossa . reported that the curvature of the head of the capitate accounted for 64 and 60% of the lunate fossa in anterior and posterior views , respectively . since the contact area of the radius with the lunate fossa is small , axial pressure from the hand may concentrate and cause fracture of the joint surface . however , the range of motion of the wrist joint had decreased and the lunate fitted into the joint surface , which may have joined the forearm with the hand like a single structure . actually , the range of motion of the wrist joint before injury was 40 on flexion and 30 on dorsiflexion in our case . regarding the carpals over the forearm as one bone , it was assumed that volar fracture was caused by a pressure loaded on the weak distal end of the radius and slight volar flexion of the wrist joint , loading a force from the dorsal side . treatment methods for drf with volar displacement include conservative treatment , pining with kirschner wire , and plate fixation . compared pinning with kirschner wire and open reduction / fixation using a volar locking plate , and observed no marked difference in the long - term postoperative outcome . similarly , gradl et al . compared non - bridging external fixation and fixation with a locking plate , and observed no difference in the long - term outcome , although a better short - term outcome was noted in the plate - treated patients . higashi et al . investigated the pressure distribution on the radiocarpal joint after drf with volar displacement using cadavers . they observed that the contact region in the radiocarpal joint was concentrated on the volar side , and the contact pressure also rose in this region , which may have been a cause of displacement toward the volar side . based on these , the patient was treated using a volar buttress plate , and a favorable postoperative course was achieved . we encountered a patient with drf after prc . the pressure distribution on the radial joint surface after prc is different from that in the normal radiocarpal joint . moreover , the range of motion of the wrist joint is limited , suggesting that the developmental mechanism of distal radius fracture is also different from that in the normal radial joint . however , it is possible to treat drf occurring after prc by selecting an appropriate treatment method for the fracture type , similarly to the treatment of drf in typical cases . written informed consent was obtained from patient for publication of this case report and accompanying images . a copy of the written consents are available for review by editor - in - chief of this journal on request . all authors have contributed significantly , and that all authors are in agreement with the content of the manuscript . yuka igeta , kiyohito naito , yoichi sugiyama , hiroyuki obata and osamu obayashi performed operation and ward management ; kiyohito naito , kentaro aritomi , kazuo kaneko and osamu obayashi diagnosed ; and yuka igeta and kiyohito naito wrote the paper .
highlightswe encountered a patient with distal radius fracture ( drf ) after proximal row carpectomy ( prc ) . 
 the mechanism of the drf after prc is discussed in this report.the drf is needed wrist range of motion . since the wrist range of motion decreased and the lunate fitted into the joint surface after prc , making the forearm join with the hand like a single structure , pressure may have been loaded on the weak distal end of the radius from the dorsal side , causing volar displacement and fracture.the pressure distribution and range of motion of the radiocarpal joint after prc are different from those of a normal joint , and the mechanism of fracture also changes with it .